TRAUMA 2023, Jan, 06 | 12:00 am

Open Reduction Internal Fixation of the Sacroiliac Joint and Sacrum

^DEFINITION

^{Pelvic fractures are serious injuries associated with a diverse assortment of morbidities and mortality rates ranging from 0% to 50%.}

^{Fractures and dislocations of the pelvis involve, in broad terms, injuries to the anterior and posterior structures of the pelvic ring.}

^{Injuries to the anterior pelvic ring include symphyseal disruption and pubic body or rami fractures.}

^{Injuries to the posterior pelvic ring involve iliac wing fractures, sacroiliac (SI) joint dislocations and fracturedislocations, and sacral fractures.}

^{The implications and treatment options vary widely depending on the spectrum of fracture patterns, the degree of displacement and potential instability, and associated injury patterns.}

^{This chapter will focus specifically on the treatment of displaced sacral fractures and SI joint dislocations.}

^ANATOMY

^{The pelvis is a ring structure composed of the two hemipelves}

^{(innominate bones) and the sacrum. Each hemipelvis is the culmination and fusion of the three embryonic bony elements: the ilium, the pubis, and the ischium (FIG 1).}

^{The two hemipelves are joined anteriorly at the pubic symphysis}

^{(a symphyseal joint), whereas posteriorly, they articulate with the wings, or alae, of the sacrum via the SI joints to complete the pelvic ring (FIG 2A,B).}

^{The sacrum represents the terminal structural segment of the spinal column that connects the pelvis and extremities to the trunk and spine.}

^{The sacrum is the caudal segment of the axial skeleton. It is, therefore, a spinal element and subject to segmentation abnormalities and dysmorphism.}

^{Most commonly, segmentation anomalies such as a lumbarized S1 or a sacralized L5 will be present (FIG 2C,D). The only way to be sure which defect, if any, is present, is to count down from the first thoracic vertebrae, which is the first vertebra to have transverse processes that are inclined cephalad.}

^{As a general rule of thumb, however, the top of the iliac crest is usually at the same level as the L4 or L5 disc space. This rule can be used to judge the presence of dysmorphism (see FIG 2C).}

^{These issues are pertinent to interpretation of the radiographic landmarks required to safely place iliosacral screws (see discussion later).}

^{Being wedge-shaped, the sacrum forms a keystone articulation with the innominate bones.}

^{By virtue of this shape and their orientation, the SI joints are inherently unstable with respect to the bony constraints, and the maintenance of posterior pelvic ring integrity is wholly dependent on the support provided}

^{by the ligamentous structures (see FIG 2A).}

^{The pelvic ligaments are structured and positioned to resist these deformations as static stabilizers of the pelvis. There are no specific dynamic stabilizers of the pelvic ring.}

^{With axial loading, the natural tendency is for each hemipelvis to externally rotate and translate in a cephalad and posterior direction. During two-legged stance, the symphysis is under tension and the SI joints experience compression superiorly and tension inferiorly. During single-leg stance, the symphysis is under compression and shear, whereas the SI joints are under tension superiorly and compression inferiorly.}

^{The SI ligaments (anterior, posterior, and intra-articular ligaments) are the strongest ligaments in the body, with the posterior SI ligaments being the most important in resisting posterior and cephalad displacement (see FIG 2B).}

^{The symphyseal ligaments (themselves contributing no more than 15% to pelvic ring stability), the sacrotuberous ligaments, and the sacrospinous ligaments resist external rotation.13, 31}

^{FIG 1 • The three embryonic bones (pubis, ischium, ilium) fusing to form the innominate bone or hemipelvis.}

³³⁸

^{FIG 2 • A. The two innominate bones and sacrum forming the pelvic ring with supporting ligaments. 1, iliolumbar; 2, SI; 3, sacrospinous; 4, sacrotuberous; and 5, symphyseal ligaments. B. SI joint ligaments. 1, posterior; 2, intra-articular; 3, anterior SI ligaments. C. Intraoperative fluoroscopy showing unilateral segmentation anomaly with partial sacralization of L5 and the level of the crest still at L4-L5. D. Three-dimensional CT reconstruction showing segmentation anomaly.}

^{The bladder is immediately posterior to the pubic bodies and symphysis, separated only by a thin layer of fat and the potential space of Retzius.}

^{The relationship of the L5 nerve root to the superior aspect of the sacral ala as it courses to join the lumbosacral plexus is a key anatomic feature that must be kept in mind during reduction and stabilization of posterior pelvic ring injuries (FIG 3A,B).}

^{FIG 3 • A,B. Neurovascular structures around the posterior pelvic ring. Note intimate relationship of L5 nerve root to sacral ala.}

^{The sacral nerve roots course from posterior to anterior, medial to lateral, and proximal to distal as they traverse the upper sacral nerve root tunnels. As they exit the sacrum, the nerve roots lay on the inferior and lateral aspect of the foramina.}

³³⁹

^{The superior gluteal artery is immediately lateral to the inferior aspect of the SI joint as it arises from the internal iliac artery to exit the greater sciatic notch with the superior gluteal nerve.}

^PATHOGENESIS

^{The SI ligaments are the most resilient in the human body and therefore must be subject to substantial forces and energy transmission to result in disruption.}

^{Anteroposterior (AP) compression of the pelvic ring causing external rotation of the innominate (which may or may not be coupled with a vertical shearing force) is the most common cause of SI joint dislocation.}

^{Sacral fractures, however, can occur in three distinctly different situations.}

^{Insufficiency fractures of the sacrum arise secondary to failure through excessively osteoporotic or osteopenic bone.}

^{Stress fractures of the sacrum resulting from fatigue and cyclic failure of normal bone in high-level athletes or military recruits}

^{Traumatic disruptions resulting from high-energy lateral or anteroposterior compression (APC) and/or vertical shear injuries such as (in order of decreasing frequency) motorcycle crashes, auto-pedestrian collisions, falls from height, motor vehicle accidents, or crush injuries.13, 31}

^{NATURAL HISTORY}

^{Pelvic fractures occur in at least 20% of blunt trauma admissions, most frequently in young males.}

^{They can result in small insignificant fractures of the pubic rami with no compromise of pelvic ring stability, or major injuries and disruptions that can be associated with lifethreatening bleeding and/or visceral injury.}

^{The pelvic ring encloses the true pelvis (organs contained below the pelvic brim, extraperitoneal) and the false pelvis (organs contained above the pelvic brim, both peritoneal and retroperitoneal).}

^{The most commonly associated injuries to structures contained within the true pelvis are the internal iliac arterial and venous systems and branches, the bladder (20%) and urethra (14%), the lumbosacral plexus, and the rectum and vaginal vault (open pelvic fractures).}

^{Injuries to structures within the false pelvis as a direct result of the pelvic fracture are uncommon, but severe iliac wing fractures with abdominal wall disruption can result in intestinal injury and even entrapment.}

^{Morbidity and mortality from pelvic fractures can be quite high and is most commonly secondary to pelvic hemorrhage.}

^{The mortality rate associated with pelvic fracture with an associated bladder rupture approaches 35% in some series.}

^{The mortality rate of open pelvic fractures involving the perineum used to be as high as 50%, but this has decreased to approximately 2% to 10% with the liberal use of diverting colostomies and more advanced stabilization techniques.}

^{Neurologic injury to the lumbosacral plexus can lead to significant sensorimotor dysfunction involving the extremities, bowel, bladder, and sexual organs.}

^{Because of these associated neurovascular and visceral injuries, pelvic fractures often result in prolonged recovery periods, significant chronic pain, permanent disability, and loss of psychological and socioeconomic structure.5, 7, 9, 19, 20, 21}

^{PATIENT HISTORY AND PHYSICAL FINDINGS}

^{Any patient presenting with a history of trauma or satisfying criteria for a Trauma Alert in the emergency department should be suspected of having a pelvic fracture until otherwise ruled out by radiologic and physical examination.}

^{The physical examination should follow the primary and secondary survey of the advanced trauma life support protocol.1}

^{Examination of a patient suspected of having a pelvic fracture should be divided into the examination of the abdomen, pelvic ring, perineum, rectum, vagina, and lower extremities.}

^{The abdominal examination should elucidate the following:}

^{Tenderness, fullness, or rigidity}

^{Abdominal wall disruptions, defects, or open wounds Flank ecchymosis}

^{Presence of internal degloving or a Morel-Lavallée lesion (separation of the subcutaneous tissues from the underlying muscular fascia). This can be recognized by subcutaneous fluctuance or a fluid wave and, later, extensive ecchymosis.}

^{The rectal and vaginal examination should consider the following:}

^{The position of the prostate (a high-riding prostate may be a sign of urethral injury) Palpable bony fragments perforating the rectal or vaginal mucosa}

^{Defects or tears in the wall of the rectum or vagina indicating possible bony penetration Rectal or vaginal bleeding indicating possible tears or bony penetration}

^{Urethral bleeding at the meatus indicating possible urethral or bladder disruption Scrotal or labial swelling and ecchymosis indicating pelvic hemorrhage (FIG 4)}

^{Rectal tone, perianal sensation, voluntary sphincter control, and bulbocavernosus reflex to assess for the presence of cauda equina syndrome or lower sacral nerve root injury}

^{FIG 4 • Scrotal ecchymosis from internal pelvic hemorrhage.}

³⁴⁰

^{Examination of the pelvic ring and extremities should focus on the following key factors:}

^{Palpable internal or external rotation instability of the pelvic ring with manually applied AP and lateral compressive forces on the iliac wings/crests. However, in an awake patient or with hemodynamic instability, multiple forceful attempts at manipulating the pelvis is not recommended, as this will be very uncomfortable to the patient and may exacerbate ongoing pelvic hemorrhage (Table 1).}

^{Leg length discrepancy with asymmetric internal or external rotation Neurologic status in patients able to comply can be assessed as follows:}

^{L1-L2: iliopsoas (hip flexors) and upper anterior thigh sensation}

^{L3-L4: quadriceps (knee extensors) and lower anterior thigh/medial calf sensation}

^{L5: extensor hallucis longus, digitorum longus (toe dorsiflexion), peroneal eversion (although this can have a strong}

^{L4 component), and lateral calf/dorsum of foot sensation}

^{S1: gastrocsoleus complex (ankle plantar flexion) and posterior calf sensation}

^{S2-S3: flexor hallucis and digitorum longus (toe plantar flexion) and sole of foot sensation}

^{Table 1 Methods for Examining the Pelvis for Stability}

^{Examination Technique Illustration Grading Significance}

^{External rotation pelvic instability}

^{Legs are positioned flexed, abducted, and externally rotated. Hands are placed on the iliac crests and an AP force is applied.}

^{N/A Palpable widening of the pelvis or increased SI joint space or symphyseal widening is seen on simultaneous fluoroscopic images with the C-arm.}

^{Internal rotation pelvic instability}

^{Legs are positioned extended, adducted, and internally rotated. Hands are positioned over the greater trochanters and a lateral to medial compressive force is applied.}

^{N/A Palpable instability of the pelvis or a decrease in SI joint space or symphyseal diastasis is seen on simultaneous C-arm images.}

^{Vertical instability}

^{Legs are positioned extended. While one extremity is supported at the heel, traction is applied to the other.}

^{N/A A visual change in leg length discrepancy can be seen in some cases.}

^{Otherwise, simultaneous C-arm images may disclose one acetabulum or iliac crest at a different level than the other.}

^{AP, anteroposterior; SI, sacroiliac.}

^{IMAGING AND OTHER DIAGNOSTIC STUDIES}

^{Plain Radiographs}

^{The standard AP (pelvis) view should be part of the initial trauma series screening. With enough experience, many of the injuries to the posterior pelvic ring can be diagnosed with this single projection (FIG 5A).}

^{A good AP radiograph should have the pubic symphysis colinear with the sacral spinous processes.}

^{This allows side-to-side comparison of bony landmarks to aid in diagnosis of subtle displacements of the sacrum or SI joint.}

^{The cortical density of the pelvic brim and iliopectineal line should be traced back to its intersection with the lateral margin of the sacral ala.}

^{This intersection should be at the same level (usually the superior margin of the S2 foramen) bilaterally.}

^{Asymmetry in the SI joint space and the appearance of the sacral foramina should alert the surgeon to the possibility of an SI joint dislocation or sacral fracture.}

^{Fractures of the L5 transverse process may be a clue to a vertical shear or severe open book pelvic injury that has avulsed the transverse process via the iliolumbar ligament.}

³⁴¹

^{FIG 5 • A. AP pelvis radiograph. Ideal film should have symphysis aligned with sacral spinous processes.}

^{B. Inlet pelvic radiograph. Note sacral promontory and alar regions. C. Outlet pelvic radiograph. Note sacral foramina and SI joints. Ideal image should have top of symphysis-rami at the S2-S3 level. D. Axial CT scan of transforaminal (Denis zone 2) sacral fracture. E. Axial CT scan of SI joint dislocation. Note}

^{diastasis of anterior and posterior joint.}

^{Symphyseal diastasis or displaced rami fractures should alert the examiner to additional injuries in the posterior ring even though they may not be readily apparent on the initial radiographic evaluation.}

^{The inlet projection is taken with the x-ray beam directed caudally approximately 45 degrees to the radiographic film.}

^{A true inlet view of the pelvis, however, may require variations on this degree of angulation because of the variations pelvic obliquity, sacral inclination, and dysmorphism. A perfect inlet view will show the anterior cortices of the sacral bodies superimposed.}

^{This view simulates a direct view into the pelvis from above along its longitudinal axis (see FIG 5B). The inlet view is helpful in imaging the following:}

^{External or internal rotation of the hemipelvis}

^{Opening of the SI joint or an impaction fracture of the sacrum}

^{“AP” displacement or translation of the hemipelvis (see the following texts)}

^{The outlet projection of the pelvis is obtained by directing the x-ray beam approximately 45 degrees cephalad to the radiographic film.}

^{A true outlet view of the sacrum, however, may require variations in this degree of angulation because of the variations in pelvic obliquity, sacral inclination, and dysmorphism. A perfect outlet view will show the sacral foramina as full circles.}

^{This view simulates looking at the sacrum and SI joints directly en face (FIG 5C). The outlet view is helpful in imaging the following:}

^{Cephalad or “vertical” shift of the hemipelvis Sacral fractures relative to the foramina Flexion-extension deformity of the hemipelvis}

^{It is important to remember that these radiographs are taken at about 45 degrees to the long axis of the patient's body.}

^{Therefore, a given amount of translation or displacement seen on the inlet or outlet view is in fact the sum of displacement vectors in both the coronal and axial planes. For example, “posterior” shift seen on the inlet projection is in fact a combination of both posterior and cephalad translation relative to the long axis of the body.}

^{Computed Tomography}

^{Computed tomographic (CT) scanning is imperative in any suspected pelvic ring injury.}

^{As the pelvis is a ring structure, any disruption in one location (no matter how seemingly insignificant) must (by virtue of ring structure mechanics) be accompanied by disruption in another location (pathologic fractures excluded).}

^{Three-millimeter axial sections (or 3 mm of vertical travel per 360-degree rotation of the gantry in a spiral CT) are recommended to disclose the majority of significant injuries (FIG 5D,E).}

³⁴²

^{FIG 6 • A. AP radiograph of patient with a U-shaped sacral fracture. Note inlet view of proximal sacrum but outlet appearance of caudal sacrum. B. Axial and sagittal CT scan reconstructions of the same patient with a U-shaped sacral fracture.}

^{Another important point to bear in mind is the appearance of the sacrum on the AP projection.}

^{If one sees a paradoxical inlet view of the upper sacrum and outlet view of the distal sacrum, a lateral x-ray and}

^{CT scan with sagittal reconstructions must be performed to rule out an occult sacral fracture-dislocation (U-shaped sacral fracture otherwise known as spinal-pelvic dissociation) (FIG 6A,B).}

^{Bilateral sacral alar fractures noted on an axial CT image of the sacrum should alert the surgeon to a U-shaped sacral fracture dislocation or spinal-pelvic dissociation.}

^{Retrograde Urethrography and Cystography}

^{Retrograde urethrography and cystography are mandatory in pelvic fractures with ring disruption to rule out urethral/bladder injury.}

^{The Foley catheter is partially inserted into the urethra, and the balloon is inflated with 2 to 3 mL of sterile saline to occlude the urethra. Ten to 15 mL of water-soluble contrast is then injected into the urethra and the outlet view of the pelvis is repeated.}

^{If no extravasation is seen, the catheter is advanced into the bladder with injection of a further 300 mL of water-soluble contrast to rule out a bladder rupture. If no contrast extravasation is noted, the bladder is drained with the catheter, and any residual dye is noted.}

^{If passage of the catheter is not possible or there is a tear of the urethra or bladder neck, suprapubic catheterization should be performed well above the umbilicus if possible (to avoid contamination of potential future anterior pelvic operations).}

^{Pelvic Angiography}

^{Angiography is indicated in those patients exhibiting persistent hemodynamic instability despite10}

^{Adequate volume resuscitation}

^{Other sources of hemorrhage being ruled out (abdomen, thorax, and long bone fractures) Attempts to “close” the pelvic ring (see the following texts) have failed to stop pelvic hemorrhage}

^{Most cases of pelvic hemorrhage (85%) arise from venous bleeding and are not amenable to angiographic embolization.}

^{Arterial bleeding is usually from branches of the internal iliac system (median sacral, superior gluteal,}

^{pudendal, or obturator arteries) (FIG 7).}

^{Arterial hemorrhage is more common in patients older than 65 years.}

^{If diagnostic peritoneal lavage is being performed to rule out abdominal hemorrhage, then it must be performed above the umbilicus and arcuate line to avoid false-positive results from pelvic hemorrhage.}

^{NONOPERATIVE MANAGEMENT}

^{As a general rule, traumatic complete SI dislocations should not be managed nonoperatively.}

^{Progressive cephalad displacement of the hemipelvis will result in pelvic malunion. Leg length inequality, chronic mechanical low back and buttock pain, pelvic obliquity with sitting imbalance, and dyspareunia are common complaints when the hemipelvis and ischial tuberosities are malpositioned.}

^{For patients in extremis, sepsis, or critical medical comorbidity, nonoperative therapy may be required until the patient can tolerate pelvic reconstruction procedures. This helps to reduce the pelvic deformity, stabilize the}

^{pelvic hemorrhage and clot, and improve patient comfort in the acute resuscitative period.2 In such cases, the pattern of deformity dictates the maneuvers to be used to minimize deformity.}

^{Patients with vertical instability should be placed into balanced longitudinal skeletal traction in an attempt to reduce and/or prevent further cephalad displacement. Traction is also an effective adjunct for hemostasis during resuscitation. Distal femoral skeletal traction is preferable.}

^{Patients with external rotation deformity of the pelvic ring (ie, an open book pelvis) should be treated with circumferential wrapping with either a sheet or commercially available pelvic binder (ie, the T-POD pelvic binder, PYNG Medical Corporation, Richmond, BC, Canada) placed over the greater trochanters. Frequent skin checks are}

³⁴³

^{mandatory to prevent full-thickness pressure ulceration and as such, they are rarely, if ever, indicated for definitive treatment (FIG 8).}

^{FIG 7 • Angiogram showing extravasation and embolization of superior gluteal artery. (Courtesy of Prof. Johannes Reuger, with permission.)}

^{FIG 8 • T-POD pelvic binder. (Courtesy of MidMed, Queensland, Australia.)}

^{Anterior pelvic external fixators can be applied either in the trauma bay or the intensive care unit (ICU) for patients in extremis.}

^{Anterior pelvic external fixators are good for controlling external and internal rotation of the anterior pelvic ring.}

^{Thus, the surgeon may elect to use them definitively in situations where the SI joint is only disrupted through the anterior SI ligaments (a type 2 injury with no vertical or sagittal plane instability) or with certain lateral compression injuries where the sacral fracture is stable by virtue of its impaction.}

^{By themselves, however, anterior external fixators are not effective in controlling the posterior pelvic ring, and if applied incorrectly, can make some pelvic deformities worse.16, 29}

^{External fixation of the posterior pelvic ring with various commercially available pelvic clamps (Pelvic C-Clamp,}

^{Synthes, Paoli, PA) are used on occasion, but expertise is required to prevent serious complications from misplacement and contaminated pin sites from their use may mitigate options for posterior fixation.8, 18}

^{In contrast to SI joint dislocations, many traumatic sacral fractures can be treated successfully with nonoperative care.}

^{Although vertical shear sacral fractures represent the far end of the spectrum of unstable sacral fractures needing operative stabilization (FIG 9), impacted sacral fractures resulting from lateral compression mechanisms can be relatively stable injuries.}

^{FIG 9 • Nonoperative treatment of vertical shear sacral fracture (white arrows) with resultant malunion and leg length inequality.}

^{FIG 10 • Impacted sacral fracture from lateral compression mechanism with internal rotation.}

^{If the radiographic and CT scanning evaluation reveals an impacted sacral alar fracture without significant displacement in other planes, a trial of nonoperative therapy is warranted if it is thought that the patient will be compliant with mobilization restrictions and appropriate radiographic follow-up to prevent late displacement and healing with a malunion (FIG 10).}

^{Often, the presentation of the patient in bed can help to predict success with nonoperative treatment of impacted sacral fractures.}

^{Those patients that are able to roll in bed on their own and help with hygienic care with only minimal or moderate discomfort often have a relatively stable pelvis and will be able to mobilize with physical therapy.}

^{Some patients, however, will not be able to tolerate even logrolling in the bed with nursing care.}

^{They may be found on examination under anesthetic to have an unstable pelvis despite innocuous-appearing imaging studies.}

^{If a patient with an impacted sacral fracture is deemed to be a candidate for nonoperative treatment, they can be mobilized with physical therapy as soon as other injuries permit.}

^{The patient is instructed to be touchdown weight bearing (TDWB) on the affected extremity for 6 weeks.}

^{If they are able to successfully mobilize, then repeat clinical examination and AP, inlet, and outlet radiographs are performed within 1 to 2 weeks to assess for any further displacement and increasing leg length inequality.}

^{SURGICAL MANAGEMENT}

^{In general, all complete SI joint dislocations and unstable displaced nonimpacted sacral fractures should be treated with operative stabilization. The choice of fixation in most instances for both SI joint dislocations and sacral fractures will be with iliosacral screws (SI screws).}

^{Biomechanical studies have validated the strength of this technique in comparison to more traditional anterior SI plating and transsacral bars and plates.11, 26}

^{SI screws can be applied with the patient in either the prone or supine position and in either an open or closed percutaneous fashion.}

^{SI screw placement requires an exacting knowledge of the radiographic correlates to anatomic landmarks to prevent serious neurologic and vascular injury.3, 6, 15, 22, 30, 32}

^{Transforaminal sacral fractures with comminution and vertical instability treated with standard SI screw fixation alone may be suboptimal in some instances and have a higher failure rate.}

^{In these instances, the surgeon may elect to place alternate forms of fixation to augment the SI screw (transsacral}

^{screws, transiliac plates, or some form of spinal pelvic construct) and resist the tendency for vertical redisplacement. This will be discussed in further detail in the following text.12, 25, 27}

^{Preoperative Planning}

^{Proper preparation and preoperative planning for any major pelvic surgery is mandatory.}

³⁴⁴

^{Pelvic reconstructive procedures can be associated with prolonged anesthetics, lengthy prone positioning, extensive blood loss, and complex reduction maneuvers that can pose serious risk to a patient with other medical or traumatic comorbidities.}

^{Having a detailed understanding of the deformity and the reduction and fixation strategy can help to significantly decrease operative time and blood loss.}

^{All patients should have anticoagulation started within 24 hours of admission.}

^{If there are contraindications to anticoagulation, inferior vena caval (IVC) filter placement should be considered in consultation with the other consulting services such as neurosurgery and critical surgeons.28}

^{If an open pelvic reduction is anticipated, waiting for 3 to 5 days is prudent to allow the pelvic clot to stabilize and diminish intraoperative bleeding.}

^{Patients should have at least 3 units of typed and crossmatched blood on hold.}

^{The surgery should be booked semielectively, if possible, with a surgical team that is familiar with complex pelvic surgery.}

^Positioning

^{Patients should be positioned on a radiolucent table for intraoperative fluoroscopy and be compatible with the ability to apply traction in some fashion.}

^{Adequate caudal translation of an unstable hemipelvis is not possible if a perineal post is in place because the ischial tuberosity and pubis tend to abut the post, preventing any movement in a caudal direction.}

^{This problem can be overcome by stabilizing the contralateral extremity in a traction boot without applying traction to provide some vertical support for the contralateral side while traction is applied to the affected extremity.}

^{Another alternative in cases with severe vertical displacement is to rigidly fix the contralateral stable pelvis to the operating table with Schanz pins and an external fixator using a pelvic stabilization frame (eg, Mizuho OSI, Union City, CA).}

^{Patient positioning will be in either the prone or supine position, depending on the injury pattern and the surgeon's assessment of the ability to achieve reduction via closed or open means.}

^{In some cases, an initial provisional reduction of the anterior pelvic ring may facilitate a closed, indirect, or percutaneous reduction of the posterior ring.}

^{However, an imperfect definitive reduction of the anterior pelvic ring with rigid stabilization can impair reduction of the more important posterior pelvic injury.}

^{For the patient positioned in the prone position (FIG 11), ensure proper padding and support for the chest to allow for adequate ventilation.}

^{FIG 11 • Positioning and setup of patient for posterior approach and reduction of sacral fracture or SI joint dislocation. Note the pelvis hanging freely, traction setup, and rigid stabilization frame on contralateral stable hemipelvis.}

^{It is preferable to use longitudinal chest rolls that come short of the pelvis, allowing the lower trunk and pelvis to hang freely and not rest on the anterior superior iliac spine (ASIS).}

^{If the pelvis is permitted to rest on the ASIS, posterior translation of the unstable hemipelvis may result and/or impair reduction.}

^{The extremity ipsilateral to the unstable hemipelvis should be draped free to allow for longitudinal traction and internal-external rotation.}

^{It should be placed in either boot or skeletal (distal femoral or proximal tibial) traction that allows for rotation and abduction-adduction.}

^{The hip should be extended and the knee flexed to relax the sciatic nerve and lumbosacral plexus (see TECH FIG 4B).}

^{Extension of the hip and lumbosacral junction and longitudinal traction will help to indirectly reduce any flexion deformity that exists.}

^{Draping of the operative field should include the entire flank on the affected side.}

^{The field should continue to include the buttock and upper thigh, with free draping of the affected extremity. The natal cleft and contralateral buttock are excluded from the field.}

^{For the patient positioned in the supine position, have a small folded sheet or pad placed under the sacrum or buttock on the affected side to lift the pelvis away from the table. Again, the affected extremity should be placed into traction to aid in reduction, as detailed earlier.}

^{If there is posterior displacement of the hemipelvis, placing the bump under the buttock will help to anteriorly translate the pelvis when traction is applied.}

^{If there is anterior translation of the hemipelvis, then placing the bump directly midline will help to lift the pelvis away from the table and also let the affected hemipelvis hang freely to allow posterior translation during reduction maneuvers.}

^{Surgical Approach}

^{Exposure of the SI joint can be accomplished from either anterior or posterior.}

^{However, if significant displacement exists and a difficult open reduction is predicted, the posterior approach should be chosen, but this will vary based on individual surgeon experience.17}

³⁴⁵

^{FIG 12 • Skin incision for posterior approach to sacrum and SI joint.}

^{Posterior Approach to the Sacroiliac Joint}

^{For the posterior approach to the SI joint, the incision is vertical and paramedian, centered directly over the involved SI joint. Do not carry the incision directly over the bony prominence of the posterior superior iliac spine (PSIS); rather, place it just medial to the PSIS (FIG 12).}

^{The tissues that bridge the SI joint posteriorly in the intact state include the lumbodorsal fascia (LDF), the transverse fibers of the gluteus maximus (TGM), the erector spinae (ES) muscles, the iliolumbar ligament, and the posterior SI ligaments (FIG 13).}

^{FIG 13 • A. Diagram of fascial fibers and muscular layers for posterior approach to sacrum and SI joint. B.}

^{Intraoperative surgical exposure of SI joint from posterior approach demonstrating the TGM.}

^{With SI joint dislocations, some or all of these fascial, muscular, and ligamentous layers may be completely disrupted, and no further dissection is needed.}

^{Often, however, to visualize the inferior aspect of the SI joint posteriorly, the TGM needs to be mobilized. The TGM attachment to the sacral spinous processes and thoracolumbar fascia is released and the TGM is reflected laterally and inferiorly to expose the inferior aspect of the SI joint. In preventing wound complications, it is imperative to preserve the attachment and origin of the TGM.}

^{Occasionally, some of the LDF will need to be released from the posterior iliac crest.}

^{This allows dissection up over the superior aspect of the SI joint and sacral ala to permit digital palpation as an assessment of reduction of the anterior SI joint.}

^{Once exposure is complete, it is usually necessary to evacuate a significant amount of blood clot and hematoma from the joint.}

^{On occasion, loose fragments of denuded articular cartilage will require removal.}

^{Routine removal of articular surfaces for a primary SI joint fusion is not routinely performed.}

^{While removing blood clot and debris, specific attention must be paid to the superior gluteal vessels and the internal iliac vascular system.}

^{Removal of clot may restart arterial bleeding that was initially controlled by tamponade and spasm, or direct iatrogenic injury may occur with dissection through the fracture hematoma and clot.}

^{All sacral fractures that necessitate an open reduction require a posterior approach.}

^{Anterior approaches are not recommended because it is not possible to dissect onto the anterior aspect of the sacrum without posing excessive risk to the lumbosacral nerve roots and iliac vessels through a traditional anterior approach to the posterior pelvic ring.}

^{The posterior approach for sacral fracture reduction varies depending on the fracture location and the need for sacral nerve root decompression.}

^{In general, however, most sacral fractures and foraminal decompressions can be performed through the same paramedian approach as described earlier for SI joint dislocations. The only alterations in technique would be as follows:}

^{Subperiosteal elevation of the paraspinal muscles from the dorsal aspect of the sacrum to the spinous processes is required to expose the whole posterior surface of the sacrum (FIG 14). Keep in mind that with a sacral fracture,}

³⁴⁶

^{the posterior SI ligaments are (usually) intact, so careful elevation of the paraspinal muscles without disruption of the posterior SI ligaments must be undertaken.}

^{FIG 14 • Posterior exposure for sacral fracture reduction.}

^{Proximal extension along the intermuscular plane of the paraspinal muscles to expose the L4-L5 facet joint can be performed in the manner described by Wiltse if a spinal pelvic construct is to be applied.}

^{Anterior Approach to the Sacroiliac Joint}

^{The anterior approach provides good visualization of the superior aspect of the SI joint and is advocated in situations where}

^{The soft tissues do not permit the posterior approach.}

^{The patient will not tolerate prone positioning because of poor pulmonary status or associated spinal injuries.}

^{A close-to-anatomic closed reduction of the SI joint can be obtained with traction, manipulation, or provisional anterior ring reduction with only minor adjustments needing to be made.}

^{The anterior approach to the SI joint uses the proximal portion of the Smith-Petersen approach by releasing the external oblique fibres from the iliac crest and elevating the iliacus muscle subperiosteally from the inner table of the ilium.}

^{FIG 15 • A. Diagram of incision and view of SI joint from the anterior approach. Note position of sharp Hohmann retractor in ala to protect the L5 nerve root. B. Visualization prior to osteotomy of the ASIS to improve anterior exposure of the posterior pelvic ring and SI joint. C. Visualization after osteotomy of the ASIS to improve anterior exposure of the posterior pelvic ring and SI joint.}

^{Remember to use the intermuscular plane between the abductors and the external oblique muscles to access the crest. The external oblique muscle tends to hang over the crest, and direct dissection down to bone through the muscle results in a weaker repair and increased postoperative pain.}

^{When the SI joint is encountered, careful mobilization of the tissue on the sacral ala using a blunt periosteal elevator and finger dissection helps to move the L5 nerve root medially out of harm's way.}

^{Once this tissue is mobilized and the sacral ala is seen under direct vision, a sharp Hohmann retractor is driven into the alar cortex and used to protect the L5 nerve root, which lies medially (FIG 15A).}

^{To improve exposure and visualization of the sacrum and SI joint anteriorly, the surgeon may elect to perform an osteotomy of the ASIS, leaving the sartorius and external oblique attached to it (FIG 15B,C).}

^TECHNIQUES

^{Open Reduction of the Sacroiliac Joint via the Posterior Approach}

^{Reduction of the dislocated SI joint is complex and requires a good knowledge of the three-dimensional anatomy of the sacrum, ilium, and SI joint.}

^{Although some AP translation and lateral-medial translation may be necessary to reduce the SI joint, longitudinal traction is the single most important indirect maneuver to perform. Adequate longitudinal traction can be assessed intraoperatively with direct visualization, digital palpation, and the image intensifier.}

^{Reduction of the superior aspect of the SI joint can be assessed with digital palpation, ensuring that the superior-anterior aspect of the SI joint is flush.}

^{Final confirmation with inlet, outlet, and AP radiographs will help disclose subtle rotational deformities not appreciated by direct visualization or palpation.}

^{Only when adequate length has been restored can the need for additional AP or medial to lateral translation be assessed.}

^{Fine-tuning of the SI joint reduction will require the placement of one or two reduction clamps to medially translate and internally rotate the hemipelvis. Large pointed reduction clamps (such as the Weber clamp or angled jaw clamps) are used.}

^{Posteriorly, a clamp can be placed over the sacral spinous process or into the posterior cortex of the sacrum inferiorly and into the cortical bone of the medial aspect of the greater sciatic notch. This can help close the inferior aspect of the SI joint (TECH FIG 1A).}

³⁴⁷

^{TECH FIG 1 • A. Weber reduction clamp positioned to reduce inferior aspect of SI joint, from posterior}

^{approach. B. Angled jaw clamp reducing superior and anterior aspect of SI. Clamp is positioned from over the top between iliac crest and L5 transverse process. C. Angled jaw clamp reducing anterior aspect of SI joint. Clamp is positioned through the greater notch onto lateral aspect of the ala, lateral to the L5 C nerve root and sacral foramina.}

^{A second clamp can be used superiorly, with one tine placed carefully over the top of the joint onto the sacral ala anteriorly and the second tine placed just lateral to the PSIS (TECH FIG 1B).}

^{Alternatively, the second clamp can be placed through the greater notch, with one tine on the sacral ala lateral to the sacral nerve roots and foramina and the other tine on the posterior cortex of the ilium (TECH FIG 1C).}

^{While these clamps are being closed to reduce the superior SI joint, internal rotation of the extremity or pushing on the anterior iliac wing with a ball spike pusher (picador) can help to close down the anterior aspect of the SI joint.}
^{Open Reduction of the Sacrum via the Posterior Approach}

^{The patient setup and surgical exposure are the same as for SI dislocations.}

^{Indirect reduction maneuvers are also the same as for SI dislocations, but clamp placement for reduction of the sacral fractures differs because the surgeon no longer has the ability to place clamps on the anterior aspect of the sacral ala.}

^{TECH FIG 2 • A. Intraoperative photograph showing clamp placement for sacral fracture reduction. B.}

^{Intraoperative fluoroscopic image showing clamp placement for sacral fracture reduction.}

^{Instead, two sharp-pointed reduction clamps can be used.}

^{One clamp is placed posteriorly from the PSIS to the inferior aspect of the sacrum by the sacral cornu (to correct residual cephalad displacement), and the second clamp is placed from a sacral spinous process to the outer table of the ilium to correct lateral displacement (TECH FIG 2A,B).}

^{Residual anterior opening of the fracture can be corrected with the iliosacral or transsacral lag screw.}

³⁴⁸
^{Open Reduction of the Sacroiliac via the Anterior Approach}

^{Once the SI joint and sacral ala have been exposed for an anterior approach as outlined earlier, reduction can be carried out.}

^{Similar to the posterior approach, longitudinal traction is applied with internal rotation of the extremity.}

^{If there is wide diastasis of the SI joint and symphysis, the surgeon may elect at this stage to expose the symphysis and temporarily reduce it with a clamp to aid in internal rotation and reduction.}

^{It is important to keep in mind, however, that permanent fixation of the symphysis at this time is not indicated as it may impede anatomic reduction of the SI joint by limiting motion of the unstable hemipelvis.}

^{If open reduction of the symphysis is performed, hold it temporarily with a clamp so that it can be removed or adjusted if the SI joint does not reduce satisfactorily.}

^{TECH FIG 3 • A. Farabeuf pelvic reduction clamp reducing the SI joint from the anterior approach using the two-screw technique. B. Intraoperative fluoroscopic image demonstrating the Jungbluth reduction clamp on the anterior aspect of the SI joint with a Hohmann retractor medially protecting the L5 nerve root. C. Anterior SI plates place to aid with reduction of the anterior SI joint and augment the SI screw for an SI dislocation.}

^{Should persistent diastasis of the SI joint exist despite these indirect maneuvers, a Jungbluth or Farabeuf reduction clamp can be used to complete the reduction.}

^{A single cortical screw is placed on either side of the SI joint into the ilium and sacral ala, respectively.}

^{The heads of the screws are left proud off the cortex, allowing the reduction clamp to engage the screw heads.}

^{The clamps can be rotated and twisted in any direction while closing the gap to achieve reduction of the joint (TECH FIG 3A,B).}

^{The reduction is verified by direct visualization and intraoperative fluoroscopy with AP, inlet, and outlet projections.}

^{As a temporary measure until definitive SI screw fixation, an anterior SI plate can be placed to help with reduction of the SI joint by placing a two- or three-hole plates with one screw in the sacral ala and another into the ilium directed back toward the PIIS (TECH FIG 3C).}
^{Placement of Iliosacral Screws}

^{Large cannulated, partially threaded lag screws are used (6.5,}

^{7.3, or 8.0 mm) so that compression can be applied to achieve maximal stability.}

^{The entry point on the external surface of the ilium is typically 10 to 20 mm anterior to the crista glutea,}

^{two-thirds of the way from the iliac crest (PSIS) to the greater sciatic notch or 2 cm up and 2 cm posterior to the notch (TECH FIG 4A).}

^{Percutaneously, the external landmark for choosing the correct entry site is the point of intersection between a line extending proximally form the greater trochanter along the axis of the femoral shaft and a horizontal line extending laterally from the PSIS (TECH FIG 4B).}

^{Percutaneously applied SI screws (particularly into the S2 segment) must be wary of injury to the superior gluteal neurovascular bundle because the entry point is in close proximity to}

^{349 350}

^{the superior gluteal neurovascular bundle as it exits the greater sciatic notch.4, 23}

^{TECH FIG 4 • A. Entry point for SI screw on outer table of the ilium. Note proximity to the superior gluteal neurovascular bundle. B. Superficial landmarks for percutaneous SI screw placement. C. Lateral projection of pelvis showing the very narrow safe corridor in S1 as bordered by the iliac cortical density (L5 nerve root), the upper sacral nerve root tunnel, and the vestigial disc space at S1-S2. The iliosacral screw is in S2. D. Outlet projection showing path of iliosacral screw for SI joint dislocation. E. Inlet projection showing path of iliosacral screw for SI joint dislocation. F. Axial CT scan showing correct trajectory through safe corridor in S1 to perform lag technique in reducing the SI joint dislocation. G,H. Axial CT scan showing dysmorphic sacrum with compromised safe corridor. I. Lateral intraoperative fluoroscopic image demonstrating an S1 iliosacral screw below the two lilac cortical densities. J. Intraoperative inlet projection demonstrating the correct trajectory for an iliosacral screw for a sacral fracture now perpendicular to the fracture plane, not the SI joint. K. Intraoperative outlet projection demonstrating the correct trajectory for an iliosacral screw for a sacral fracture now perpendicular to the fracture plane not the SI joint. L. Intraoperative fluoroscopic AP projection demonstrating the use of a transiliac plate and transsacral screw for fixation of a sacral fracture.}

^{“Safe” placement is maximized by careful attention to radiographic bony landmarks.3, 6, 22, 32}

^{The three critical projections for placing an SI screw are as follows:}

^{The lateral projection to center the guidewire on the sacral body anterior to the canal and upper sacral nerve root tunnel and below the iliac cortical density (L5 nerve root) (TECH FIG 4C)}

^{The outlet projection to ensure that the guidewire passes above or between the sacral foramina (TECH FIG 4D)}

^{The inlet projection to ensure that the guidewire is at the proper trajectory and coming to rest in the anterior aspect of the sacral body-promontory for maximal purchase (TECH FIG 4E)}

^{Be attentive to sacral dysmorphism and segmentation defects that give rise to altered anatomy such as lumbarized S1 or sacralized L5 vertebral bodies (TECH FIG 4E,F) and result in atypical safe trajectories and corridors for SI screws.}

^{The case shown in FIG 2C,D demonstrates a unilateral sacralized L5 on the right. The left side is normal. Note that iliac crest is in line with the L4-L5 disc space.}

^{The safe corridor for the SI screw is between the valley of the ala anteriorly (L5 nerve root), the sacral canal posteriorly (cauda equina), and the sacral foramen inferiorly (S1 nerve root) (TECH FIG 4F).}

^{Note that in the normal situation (no segmentation abnormality), the corridor is well defined (TECH FIG 4F), but in the case of a sacralized L5, the safe corridor is either exceedingly narrow or nonexistent (TECH FIG 4G,H). If this abnormality is not recognized and an SI screw is placed into L5 assuming it is S1, the L5 nerve root is likely to be injured. If the surgeon is unsure, the lateral projection with the iliac cortical densities is key in determining the correct level to place the screw because they are constant with their relationship to S1 even in segmentation abnormalities (TECH FIG 4I).}

^{For SI joint dislocations, the screw trajectory should be from inferior to superior on the outlet view and from posterior to anterior on the inlet view (perpendicular to the plane of the SI joint). Placement of the screw outside of this trajectory may result in shear rather than compression of the SI joint and therefore displace or malreduce the SI joint (TECH FIG 4D,E).}

^{For sacral fractures, the screw trajectory should be straight across from lateral to medial on the inlet and outlet view (perpendicular to the fracture plane; see TECH FIG 4J,K).}

^{The tip of the SI screw should come to rest in the contralateral side of the S1 body and promontory. Carrying the screw into the contralateral ala provides weaker purchase secondary to poor bone quality and increased risk to the contralateral L5 nerve root.}

^{In situations of comminuted transforaminal sacral fractures, the theoretical risk of overcompression and iatrogenic L5 or sacral nerve root injury exists. To gain stability with the construct and avoid a nonunion, some compression is, however, necessary.}

^{If the sacral fracture is comminuted and fragments of bone are noted to be in the foramen, then sacral nerve root decompression can be readily performed through the fracture to mitigate the risk of iatrogenic nerve injury during the reduction and compression of the fracture.}

^{If inadequate compression secondary to heavy comminution exists, then supplemental forms of fixation such as transsacral screws, transiliac plates, or spinal pelvic fixation should be considered (TECH FIG 4L).}
^{Spinal Pelvic Fixation}

^{This technique is also known by the terms lumbopelvic fixation and triangular ostesynthesis.14, 24}

^{The purpose of this technique is to augment SI screw fixation for a very unstable posterior ring injury that has been reduced and temporarily stabilized but at risk for failure of fixation and subsequent redisplacement—usually in the case of extensively comminuted transforaminal sacral fractures.}

^{Through the posterior approach as described earlier, the L4-L5 facet joint is exposed, taking care not to disrupt the capsule.}

^{A Schanz screw (USS thoracolumbar fracture system, Synthes USA, Paoli, PA) or any other pedicle screw system is placed into the L5 pedicle, with the entry point being at the junction of the transverse process and the lateral border of the facet joint.}

^{A second Schanz screw or pedicle screw is placed into the ilium at the PSIS and then directed between the inner and outer tables of the ilium along the sciatic buttress toward the anterior inferior iliac spine (AIIS).}

^{The trajectory should be aiming for the ipsilateral greater trochanter as an external landmark. The screw should be directed to pass through the region of the sciatic buttress above the greater sciatic notch as seen on the iliac oblique view.}

^{Safe placement out of the SI joint and within the confines of the inner and outer tables can be confirmed on the obturator-outlet oblique view (TECH FIG 5A).}

^{The pedicle and iliac screws are then connected with fixed angle clamps and a 5.0-mm rod, thus supplementing the SI screw to resist vertical displacement and rotation around the SI screw (TECH FIG 5B).}

^{It is important to keep in mind that sacral fracture reduction and fixation with an SI screw as described earlier should be performed prior to placement of any spinal pelvic construct.}

^{This avoids rigid fixation with residual sacral gap and subsequent nonunion or delayed union.}

³⁵¹

^{TECH FIG 5 • A. Obturator outlet (left) and iliac (right) oblique views to show the path of the iliac screw for triangular osteosynthesis; note that path is between the inner and outer tables (outlined in red hashmarks) on the obturator oblique view and just above the sciatic buttress on the iliac oblique view. B. AP radiograph of the pelvis after spinal pelvic fixation (triangular osteosynthesis).}
^{Sacral Nerve Root Decompression}

^{This will be indicated in one of two situations:}

^{The patient has a peripheral neurologic deficit (radiculitis or radiculopathy) attributable to a sacral nerve root injury and preoperative imaging shows fracture fragments within the sacral foramen.}

^{The patient is neurologically intact, but preoperative imaging studies disclose a large bone fragment within the foramen that during reduction will further compress the nerve root and stenose the foramen, resulting in iatrogenic nerve root injury (TECH FIG 6A).}

^{In most cases of transforaminal fractures, the incriminating fragment of bone can be found and removed by working directly through the fracture in the sacrum (TECH FIG 6B).}

^{A laminar spreader can be placed into the fracture to spread the respective portions of the fracture.}

^{After the clot is removed, careful dissection along the exposed surface of the medial sacral fragment will disclose some portion of the foramen.}

^{Tracing the nerve root anteriorly will usually lead to the bone fragment.}

^{TECH FIG 6 • A. Axial CT scan of a sacral fracture showing large intraforaminal bony fragment. B. Intraoperative photograph demonstrating decompression the sacral nerve root directly through the sacral fracture.}

^{Occasionally, a Kerrison and pituitary rongeur will be needed to remove some portion of the sacral lamina to find the nerve root, so these instruments should always be readily available.}

^{Zone 3 Sacral Fractures}

^{Vertically oriented zone 3 sacral fractures are usually the result of wide APC forces and are associated with anterior ring disruption.}

^{Generally, they can be treated with internal rotation and anterior ring fixation alone.}

^{If residual sacral gapping persists, however, an SI screw with short threads can be placed into the contralateral S1 body to close the residual ga}

^{U-Shaped Sacral Fractures}

^{Otherwise known as spinal-pelvic dissociation, this fracture is essentially a sacral fracture-dislocation.}

^{It tends to occur through the vestigial disc space and result in kyphosis.}

^{These fractures can be easily missed on the standard AP pelvis radiograph and axial CT scans, making the sagittal CT}

³⁵²

^{reconstruction of paramount importance in diagnosing this injury (see FIG 6A,B).}

^{These injuries generally do not result in pelvic ring instability as the SI joints and distal surrounding sacrum are intact. They are more commonly associated with spinal instability.}

^{These injuries can be associated with cauda equina syndrome and significant spinal instability and should be treated by a surgeon experienced in treating injuries to the distal axial skeleton.}

^{TECH FIG 7 • A. AP radiograph showing a patient with a U-shaped sacral fracture with spinal-pelvic dissociation treated with a spinal pelvic construct to restore the posterior tension band and stabilize the fracture. B. Lateral radiograph showing a patient with a U-shaped sacral fracture with spinal-pelvic dissociation treated with a spinal pelvic construct to restore the posterior tension band and stabilize the fracture.}

^{Fractures with minimal kyphotic deformity, impaction, and no sacral canal compromise or neurologic deficit can be managed with percutaneous bilateral SI screw or transsacral screw fixation alone.}

^{Fractures with severe kyphosis and neurologic deficit require open reduction, decompression, and some form of bilateral posterior lumbopelvic fixation to restore the posterior tension band and control sagittal deformity (TECH FIG 7A,B).}

^{PEARLS AND PITFALLS}

^Pitfall

^{Salvage or Bailout}

^{Poor SI screw}

^purchase

^{Placement of a second SI screw into S2}
^{Ensure appropriate length into anterior aspect of sacral vertebral body and promontory. Alar purchase is poor secondary to low bone density here.}
^{Placement of a transsacral SI screw into contralateral SI joint}
^{Placement of transiliac plates}

^{Fixation of sacral}

^{fracture with residual gap}

^{Use clamps and SI screw to close the fracture gap under fluoroscopic}

^{control, without overcompressing.}
^{Do not use spinal pelvic fixation construct prior to manipulative reduction and placement of SI screw as it will lock down the fracture, preventing}

^{reduction and gap closure.}

^{SI screw malpositioning}	^{If any symptoms or signs of radiculitis or radiculopathy exist, then postoperative CT scan and screw removal is indicated. If patient is asymptomatic from a misplaced screw, then observation is warranted. However, if symptoms develop at a later date, then the nerve root may scar or become adherent to the screw, making removal more difficult.}
^{Sacral dysmorphism}	^{Close scrutiny of the preoperative CT scan is important to plan out the safest trajectories and measure the diameter of the potential corridors.} ^{Unilateral segmentation defects are also common.} ^{Three-dimensional reconstructions are often helpful in diagnosing sacral dysmorphism and assessing the region of the sacral ala relative to the first sacral foramen.}
^{Wound dehiscence/infection}	^{These should be treated early and aggressively to avoid deep-seated pelvic abscesses and infections.} ^{Prolonged drainage after 4-5 days (whether the patient is febrile or not and whether the white cell count is elevated or not) should be considered for a return to the operating room for open irrigation and débridement and drainage. Incisional negative pressure dressings may help to seal the wound, control drainage, and prevent wound dehiscence.}
^{Patient wakes up with new neurologic deficit (iatrogenic nerve injury, most commonly L5)}	^{First, preoperatively, the patient should be informed of the risk of neurologic injury that can occur with reduction.} ^{CT scan is ordered to assess for possible causes for nerve root injury:} ^{Malpositioned screw: remove} ^{Bone fragment (usually from sacral fracture): decompress, usually anteriorly on top of ala} ^{However, postoperative CT scan may not disclose any offending etiology, in which case, observation and prayer is indicated.}
^{Inability to reduce the SI joint or sacral fracture}	^{First, ensure that adequate longitudinal traction is applied, as that is the key to reduction.} ^{Do not use a standard fracture table with a perineal post as this will impede caudal translation of the hemipelvis.}

³⁵³

^{POSTOPERATIVE CARE}

^{Provided that all other injuries permit, the patient is mobilized the first postoperative day.}

^{The patient is instructed to be TDWB on the ipsilateral extremity for 10 to 12 weeks for SI dislocations and sacral alar fractures stabilized with SI screws.}

^{Patients with spinal pelvic fixation can be allowed to full weight bear within 4 to 6 weeks.}

^{All patients are given a regimen of pelvic, core trunk, hip, and knee range-of-motion exercises.}

^{Common early postoperative problems in patients with severe pelvic fractures include ileus and urinary retention and these need to be addressed early.}

^{The urinary catheter is usually not removed until the patient can mobilize well with physical therapy. Diet is not advanced until flatus and normal bowel sounds have returned.}

^{Anticoagulation is administered in all patients for 6 weeks with low-molecular-weight heparin or Coumadin for deep venous thrombosis and pulmonary embolism prophylaxis.}

^OUTCOMES

^{Outcome studies after fixation of pelvic fracture-dislocations are difficult to interpret because of poor followup, heterogeneity of the injury pattern, associated visceral and neurologic injury, and the lack of a reliable outcome measures for pelvic ring injuries.}

^{Improved short-term patient outcome with early stabilization and mobilization of the patient with a pelvic fracture as well as numerous reports citing improved outcome with anatomic reduction of the posterior ring continued to provide the impetus to develop more rigid and stable posterior fixation constructs.}

^{Earlier outcome studies support the position that the longterm functional results are improved if reduction with less than 1 cm of combined displacement of the posterior ring is obtained, especially with pure dislocations of the SI complex.}

^{Fractures of the posterior ring, as opposed to pure SI dislocations (ligamentous injuries), tend to display superior functional outcomes—presumably because of bony healing that restores preinjury strength and stability to the pelvic ring. Conversely, SI dislocations rely on ligamentous healing and scar formation—as a result, these patients tend to have worse functional outcomes in the short term and long term with pain and ambulation when compared to patients with other injury patterns.}

^{More recent detailed clinical outcome studies have shown that with current fixation techniques, a substantial proportion of patients continue to have poor outcomes with chronic posterior pelvic pain despite seemingly anatomic reductions and healing, with less than 50% returning to previous level of function and work status.}

^{This disparity in results is likely related to multiple confounding factors, such as Poor financial and psychosocial and emotional status of trauma patients}

^{The extensive soft tissue damage and associated long bone and extremity fractures}

^{Associated neurologic, visceral, and urogenital injuries resulting in dyspareunia, sexual dysfunction, and incontinence}

^{Prolonged recovery and rehabilitation time with loss of job, home, and family and dog.}

^{COMPLICATIONS}

^{Blood loss and the need for transfusion are common with any open procedure on the posterior pelvic ring, particularly with open reduction of the SI joint and sacral fracture, where injury to the superior gluteal artery is always a danger.}

^{Wound infection occurs surprisingly infrequently given the medical condition of these patients, prolonged ICU and hospital admission, and associated soft tissue injury.}

^{Infection and wound complications occur in approximately 3% of operative cases.}

^{Patients with internal degloving injuries (a Morel-Lavallée lesion), where the skin and subcutaneous fatty layer are sheared and separated from the underlying musculofascial layers, are particularly prone to severe wound complications with dehiscence, necrosis, and slough.}

^{Patients identified as having an internal degloving lesion in the area of operative approach should first have drainage and débridement of the lesion, and the reduction and placement of fixation should be performed through an alternate approach.}

^{Similarly, patients who have undergone angioembolization during resuscitation for pelvic hemorrhage may be at higher risk for wound complications during extensive open posterior reconstructions—particularly if nonselective bilateral embolization techniques were used.}

³⁵⁴

^{Neurologic injury from manipulation of fracture fragments or placement of SI screws is a possibility.}

^{Careful attention to the radiologic landmarks and clear appropriate imaging should allow the surgeon to avoid these iatrogenic complications, although even smooth gentle reductions of widely displaced fractures and dislocations can result in neurapraxic injury to the nerve roots and postoperative deficits.}

^{Patients need to be informed of this risk preoperatively.}

^{The risk of misplaced SI screws varies widely with surgeon and individual experience.}

^{Loss of reduction and failure of fixation can occur in very comminuted and unstable fracture-dislocations, particularly in patients with poor bone quality.}

^{These situations should be recognized intraoperatively and the appropriate supplemental fixation (additional SI screws transsacral screws, transiliac plates, or spinal pelvic fixation constructs) should be applied.}

^{Nonunion of sacral fractures and SI dislocations is a rare occurrence and not reported specifically in the literature.}

^{Rigidly stabilizing a sacral fracture with a residual gap predisposes to malunion and nonunion. Some patients with SI dislocations continue to have chronic SI joint pain, requiring SI joint fusion.}

^REFERENCES

^{American College of Surgeons Committee on Trauma. Advanced Trauma Life Support for Doctors, ed 7. Chicago: American College of Surgeons Committee on Trauma, 2004.}
^{Bottlang M. Noninvasive reduction of open-book pelvic fractures by circumferential compression. J Orthop Trauma 2002;16:367-373.}
^{Carlson DA, Scheid DK, Maar DC, et al. Safe placement of S1 and S2 iliosacral screws: the “vestibule” concept. J Orthop Trauma 2000;14(4):264-269.}
^{Collinge C, Coons D, Aschenbrenner J. Risks to the superior gluteal neurovascular bundle during percutaneous iliosacral screw insertion: an anatomical cadaver study. J Orthop Trauma 2005;19(2):96-101.}
^{Dalal SA, Burgess AR, Siegel JH, et al. Pelvic fracture in multiple trauma: classification by mechanism is the key to pattern of organ injury, resuscitative requirements, and outcome. J Trauma 1989;29(7):981-1002.}
^{Day CS, Prayson MJ, Shuler TE, et al. Trans-sacral versus modified pelvic landmarks for percutaneous iliosacral screw placement—a computed tomographic analysis and cadaveric study. Am J Orthop 2000;29(9 suppl):16-21.}
^{Demetriades D, Karaiskakis M, Toutouzas K, et al. Pelvic fractures: epidemiology and predictors of associated abdominal injuries and outcomes. J Am Coll Surg 2002;195:1-10.}
^{Ertel W, Keel M, Eid K, et al. Control of severe hemorrhage using C-clamp and pelvic packing in multiply injured patients with pelvic ring disruption. J Orthop Trauma 2001;15:468-474.}
^{Flancbaum L, Morgan AS, Fleisher M, et al. Blunt bladder trauma: manifestation of severe injury. Urology 1988;31:220-222.}
^{Gansslen A, Giannoudis P, Pape HC. Hemorrhage in pelvic fracture: who needs angiography? Curr Opin Crit Care 2003;9:515-523.}
^{Gorczyca JT, Varga E, Woodside T, et al. The strength of ilio-sacral lag screws and transiliac bars in the fixation of vertically unstable pelvic injuries with sacral fractures. Injury 1996;27(8):561-564.}
^{Griffin DR, Starr AJ, Reinert CM, et al. Vertically unstable pelvic fractures fixed with percutaneous iliosacral screws: does posterior injury pattern predict fixation failure? J Orthop Trauma 2003;17(6):399-405.}
^{Hearn TC, Tile M. The effects of ligament sectioning and internal fixation of bending stiffness of the pelvic ring. In Proceedings of the 13th International Conference on Biomechanics. Perth, Australia, December, 1991.}
^{Kach K, Trentz O. Distraction spondylodesis of the sacrum in “vertical shear lesions” of the pelvis. Unfallchirurg 1994;97(1):28-38.}
^{Keating JF, Werier J, Blachut P, et al. Early fixation of the vertically unstable pelvis: the role of iliosacral screw fixation of the posterior lesion. J Orthop Trauma 1999;13(2):107-113.}
^{Kellam J. The role of external fixation in pelvic disruptions. Clin Orthop 1989;241:66-82.}
^{Moed BR, Karges DE. Techniques for reduction and fixation of pelvic ring disruptions through the posterior approach. Clin Orthop Rel Res 1996;(329):102-114.}
^{Pohlemann T. Pelvic emergency clamps: anatomic landmarks for a safe primary application. J Orthop Trauma 2004;18:102-105.}
^{Raffa J, Christensen NM. Compound fractures of the pelvis. Am J Surg 1976;132:282-286.}
^{Richardson JD, Harty J, Amin M, et al. Open pelvic fractures. J Trauma 1982;22:533-538.}
^{Rothenberger DA, Velasco R, Strate F, et al. Open pelvic fracture: a lethal injury. J Trauma 1978;18:184-}

^187.
^{Routt ML, Simonian PT, Agnew SG, et al. Radiographic recognition of the sacral alar slope for optimal placement of iliosacral screws: a cadaveric and clinical study. J Orthop Trauma 1996;10(3):171-177.}
^{Routt ML, Simonian PT, Mills WJ. Iliosacral screw fixation: early complications of the percutaneous technique. J Orthop Trauma 1997;11(8):584-589.}
^{Schildhauer TA, Josten C, Muhr G. Triangular osteosynthesis of vertically unstable sacrum fractures: a new concept allowing early weightbearing. J Orthop Trauma 1998;12(5):307-314.}
^{Schildhauer TA, Ledoux WR, Chapman JR, et al. Triangular osteosynthesis and iliosacral screw fixation for unstable sacral fractures: a cadaveric and biomechanical evaluation under cyclic loads. J Orthop Trauma 2003;17(1):22-31.}
^{Simonian PT, Routt ML. Biomechanics of pelvic fixation. Orthop Clin North Am 1997;28(3):351-367.}
^{Simonian PT, Routt ML, Harrington RM, et al. Internal fixation of the transforaminal sacral fracture. Clin Orthop 1996;323:202-209.}
^{Steele N, Dodenhoff RM, Ward AJ, et al. Thrombo-prophylaxis in pelvic and acetabular trauma surgery. The role of early treatment with low-molecular weight heparin. J Bone Joint Surg 2005;87(2):209-212.}
^{Stocks GW, Gabel GT, Noble PC, et al. Anterior and posterior internal fixation of vertical shear fractures of the pelvis. J Orthop Res 1991;9:237-245.}
^{Templeman D, Schmidt A, Freese J, et al. Proximity of iliosacral screws to neurovascular structures after internal fixation. Clin Orthop 1996;(329):194-198.}
^{Vrahas M, Hearn TC, Diangelo D, et al. Ligamentous contributions to pelvic stability. Orthopedics 1995;18(3):271-274.}
^{Xu R, Ebraheim NA, Robke J, et al. Radiologic evaluation of iliosacral screw placement. Spine 1996;21(5):582-588.}

Open Reduction Internal Fixation of the Sacroiliac Joint and Sacrum

Search in this site

Open Reduction Internal Fixation of the Sacroiliac Joint and Sacrum

DEFINITION

ANATOMY

PATHOGENESIS

NATURAL HISTORY

PATIENT HISTORY AND PHYSICAL FINDINGS

Table 1 Methods for Examining the Pelvis for Stability

IMAGING AND OTHER DIAGNOSTIC STUDIES

Plain Radiographs

Computed Tomography

Retrograde Urethrography and Cystography

Pelvic Angiography

NONOPERATIVE MANAGEMENT

SURGICAL MANAGEMENT

Preoperative Planning

Positioning

Surgical Approach

TECHNIQUES

Open Reduction of the Sacroiliac Joint via the Posterior Approach

Open Reduction of the Sacrum via the Posterior Approach

Open Reduction of the Sacroiliac via the Anterior Approach

Placement of Iliosacral Screws

Spinal Pelvic Fixation

Sacral Nerve Root Decompression

PEARLS AND PITFALLS

POSTOPERATIVE CARE

OUTCOMES

COMPLICATIONS

REFERENCES

^DEFINITION

^ANATOMY

^PATHOGENESIS

^{NATURAL HISTORY}

^{PATIENT HISTORY AND PHYSICAL FINDINGS}

^{Table 1 Methods for Examining the Pelvis for Stability}

^{IMAGING AND OTHER DIAGNOSTIC STUDIES}

^{Plain Radiographs}

^{Computed Tomography}

^{Retrograde Urethrography and Cystography}

^{Pelvic Angiography}

^{NONOPERATIVE MANAGEMENT}

^{SURGICAL MANAGEMENT}

^{Preoperative Planning}

^Positioning

^{Surgical Approach}

^TECHNIQUES

^{Open Reduction of the Sacroiliac Joint via the Posterior Approach}

^{Open Reduction of the Sacrum via the Posterior Approach}

^{Open Reduction of the Sacroiliac via the Anterior Approach}

^{Placement of Iliosacral Screws}

^{Spinal Pelvic Fixation}

^{Sacral Nerve Root Decompression}

^{PEARLS AND PITFALLS}

^{POSTOPERATIVE CARE}

^OUTCOMES

^{COMPLICATIONS}

^REFERENCES