BACKGROUND

 

 

The pelvis is a relatively common anatomic location for metastatic and primary musculoskeletal tumors.

 

Surgical resection is more challenging in the pelvis than in other locations because of the complex anatomy and the proximity to vital abdominal viscera and major blood vessels and nerves. Making decisions about surgical resectability of a tumor involves the assessment of possible osseous or neurovascular involvement, in addition to the possible involvement of adjacent viscera (ie, bowel, ureter, and bladder). Therefore, preoperative evaluation and extensive imaging are critical. Osseous resection and reconstruction usually are carried out adjacent to major nerves, beneath the iliac vessels, or adjacent to the bladder or bowel.

 

Tumor surgery around the pelvis has the highest rate of complications, infections, and mechanical failure of all anatomic sites.

 

ANATOMY

Pelvic Nerves

Sciatic Nerve

 

The sciatic nerve arises from L4, L5, S1, S2, and S3. The nerve emerges from the pelvis through the greater sciatic notch inferior to the piriformis muscle and enters the thigh lateral to the ischial tuberosity. In 10% of patients, the sciatic nerve penetrates the substance of the piriformis muscle. The sciatic nerve is accompanied by the inferior gluteal artery.

 

It is essential to protect the sciatic nerve early in most procedures. Inside the pelvis, the nerve should be identified distally at the greater sciatic notch. Proximally, it should be picked up below the psoas muscle. The sciatic nerve is formed at the junction of the lumbar sacral plexus where these two trunks come together.

 

Great care must be taken, as the nerve exits the pelvis at the level of the greater sciatic notch, not to injure the accompanying inferior and superior gluteal nerves and arteries because these supply the abductors as well as the gluteus maximus muscle. The gluteus maximus muscle is essential for closure of most pelvic resections.

 

Femoral Nerve

 

The femoral nerve arises from posterior divisions of the ventral rami of L2 and L3 and passes inferolaterally between the psoas and iliacus muscles. It passes over the superficial iliacus muscle to enter the proximal thigh underneath the inguinal ligament, just lateral to the superficial femoral artery.

 

This nerve is almost always preserved during pelvic resections. It should be identified early during most procedures. The femoral nerve is identified in the space between the iliacus and psoas muscles as they exit the pelvis. The femoral nerve lies just below the fascia, bridging the interval between the two muscles, lateral to the femoral artery and vein.

 

Obturator Nerve

 

The obturator nerve, formed from the anterior branches of L2, L3, and L4, is the largest nerve formed from anterior divisions of the lumbar plexus. The nerve descends thru the iliopsoas muscle and courses distally over the sacral ala into the lesser pelvis, lying lateral to the ureter and under the internal iliac vessels. It then traverses the obturator foramen into the medial thigh, under the superior pubic ramus, dividing into anterior and posterior branches.

 

This nerve is routinely transected during pelvic floor resections (type III) due to its intimate proximity to the tumor.

 

Lumbar Plexus Sensory Nerves

 

The iliohypogastric (L1), ilioinguinal (L1), genitofemoral (L1, L2) and lateral femoral cutaneous nerves, which arises from L2 and L3, travel downward laterally along the iliopsoas muscle, pass underneath the lateral aspect of the inguinal ligament, and pass just distal and medial to the anterior superior iliac crest to innervate the anterolateral thigh.

 

This nerve is sacrificed during most pelvic surgical procedures.

 

Pelvic Vessels

Aortic Bifurcation

 

Descending the abdomen to the left of the vena cava, the aorta bifurcates at the level of L4 into common iliac vessels at the level of L4-L5. The common iliac bifurcates into internal and external iliacus vessels at the level of S1, the ala sacralis. The level of these bifurcations may vary, especially if the vessels are pushed by a large adjacent tumor mass (FIG 1A).

 

It is essential to identify two levels of bifurcations before any ligation: the aortic bifurcation and the common iliac bifurcation. Even the best surgeons have ligated the wrong vessels due to distorted anatomy. Such a misstep is especially possible with tumors that cross the midline. Preoperative evaluation with angiography is required for a comprehensive evaluation.

 

Common Iliac Artery

 

 

The common iliac artery must be identified early to correctly identify the aorta as well as the internal iliac (hypogastric)

 

 

artery (FIG 1B). To the surgeon, the major anatomic features of the common iliac artery are as follows:

 

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FIG 1 • A. The bony pelvis and its relation to the major blood vessels, nerves, and visceral organs. B. Surgical illustration demonstrating critical vascular anatomy of the pelvis. Specific attention must be paid regarding common iliac and internal/external iliac vessels and requires achieving vascular control during pelvic resection. (A: Courtesy of Martin M. Malawer.)

 

 

No arterial branches arise from the artery (although the common iliac vein does have a major branch joining in, the iliolumbar vein).

 

The bifurcation of the common iliac artery into the external and internal iliac arteries is at the exact level at which the ureter crosses on the adjacent peritoneal surface. The ureter is routinely identified at this location early in the retroperitoneal dissection.

 

Failure to achieve vascular control of the common external or internal iliac artery or vein can result in uncontrolled blood loss as a consequence.

 

External Iliac Artery

 

The external iliac artery contributes to the inferior epigastric artery and extends distally, as the superficial femoral artery, into the femoral triangle, where it is a useful landmark in identifying neighboring structures.

Internal Iliac Artery

 

The internal iliac (hypogastric) artery descends from the lumbosacral articulation to the greater sciatic notch and branches into several arteries. The internal iliac artery and vein often are difficult to identify or ligate. The internal iliac artery lies on top of its vein, which often is large and is easily injured. The hypogastric vessels are routinely ligated in performing modified hemipelvectomies as well as many pelvic resections.

 

Anterior branches

 

 

The obturator artery exits the pelvis via the obturator canal (beneath the superior pubic ramus).

 

The inferior gluteal artery curves posteriorly between the first and second or second and third sacral nerves, then runs between the piriformis and coccygeus muscles or through the greater sciatic foramen into the gluteal region below the piriformis muscle.

 

Posterior branches

 

 

The iliolumbar artery ascends posterior to the obturator nerve and external iliac vessels to the medial border of the psoas. It then divides into the lumbar branch, to the psoas and quadratus lumborum muscles and to the spinal cord, and an iliac branch, to the iliac, gluteal, and abdominal musculature. The iliac branch often is ligated during surgery.

 

The superior gluteal artery runs posteriorly between the lumbosacral trunk and first sacral nerve and leaves the pelvis through the greater sciatic foramen superior and posterior to the piriformis muscle. Great care must be taken to preserve the gluteal vessels and nerves when performing types I and II pelvic resections.

 

Ureter

 

The ureter originates from the renal pelvis at the level of L1 and courses in the retroperitoneum to the medial surface of the psoas major muscle, crossed by spermatic or ovarian vessels.

 

 

The ureter crosses from lateral to medial on the surface of the peritoneum at the level of the common iliac bifurcation. This is a good landmark to identify the ureter during the initial retroperitoneal dissection.

 

The ureter then courses medially at the level of the sciatic notch to insert into the trigone of the bladder.

 

Corona Mortis

 

The corona mortis is an anastomosis of the external iliac, inferior epigastric, and obturator vessels located in the retropubic region approximately 3 cm from the symphysis pubis. Laceration during an ilioinguinal approach can lead to extensive bleeding.

 

The retroperitoneal space between pubis and bladder is called the space of Retzius.

 

Inguinal Canal

 

The anatomic confines of the inguinal canal are described as 4 cm from the deep inguinal ring to the subcutaneous ring. This “deep ring” is the “direct” inguinal space originating lateral to the epigastric vessels. Hesselbach triangle is the “indirect” hernia space originating medial to the epigastric vessels.

 

The inguinal contents vary by gender:

 

 

In males, the spermatic cord contains the ductus deferens, testicular artery, pampiniform plexus, lymphatics, autonomic nerves, the ilioinguinal and genital branches of the genitofemoral nerve, the cremasteric artery and muscle, and the internal spermatic fascia.

 

In females, the inguinal contents include the round ligament and the ilioinguinal nerve.

 

The anterior inguinal wall is formed by the aponeurosis of the external oblique and internal oblique (lateral) muscles.

 

 

The posterior inguinal wall runs medial to lateral and is formed by the reflected inguinal ligament, the inguinal falx, and the transversalis fascia. The superior or cephalic inguinal wall is formed by arched fibers of the internal oblique muscle and the transverse muscle of the abdomen.

 

The inferior or caudal inguinal wall is formed by the inguinal and lacunar ligaments.

 

Boundaries

 

 

The sciatic notch should be identified early in surgery, both internally and externally, to protect the sciatic nerve and gluteal pedicles. The superior cephalad margin of the pelvis is defined by the ilium and the rim of the great sciatic notch.

 

The posterior margin of the pelvis is bounded by the piriformis muscle and the superior gluteal vessels and nerve. Posterior to the piriformis muscle, the internal pudendal vessels and nerve course medially off the sciatic nerve and the posterior femoral cutaneous nerve, anterior to the piriformis.

 

Inferior margin: The sacrospinous and sacrotuberous ligaments are released during types I and II pelvic resections.

 

INDICATIONS

Recurrent Benign Tumors

 

 

Major pelvic resections rarely are performed for benign bony tumors. Occasionally, following multiple recurrences or when tumors are limited to either the superior or inferior pubic rami, pelvic resection is indicated.

Such benign tumors include large solitary osteochondromas or any osteochondroma associated with multiple hereditary exostosis due to the high risk of secondary chondrosarcoma.

Osteoblastoma occurring in the ilium or periacetabulum

Giant cell tumors or aneurysmal bone cysts have a predilection for the superior pubic ramus and supra-acetabulum.

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Primary Malignant Osseous Tumors

Osteosarcoma

Five percent of all osteosarcomas occur in the pelvis. Partial pelvic resection or hemipelvectomy (amputation) is required, usually following induction chemotherapy.

Ewing sarcoma

About 25% of all Ewing sarcomas occur in the pelvis. Surgical resection is required.

Adjuvant radiation therapy is recommended in treating pelvic Ewing sarcoma with surgical resection. Resection should be performed only following induction chemotherapy.

Chondrosarcoma

Chondrosarcomas are the most common primary malignant bony tumors of the pelvis.

They often are much larger than plain radiographs indicate. Further imaging with magnetic resonance imaging (MRI) demonstrates the cartilaginous component of the tumor.

Metastatic Adenocarcinoma: Breast, Prostate, Renal, Lung, Colon

Metastatic adenocarcinoma most commonly involves iliac or periacetabular sites. Most metastatic tumors to the pelvis are treated adequately with radiation therapy.

Occasionally, there may be significant acetabular destruction with an impending pathologic fracture that requires surgical reconstruction.

Renal cell carcinoma (hypernephroma) metastases are an exception. These metastases often require surgical removal, either by resection or by curettage and cryosurgery. Preoperative embolization always is required for these vascular tumors to avoid severe bleeding during surgery.

Soft Tissue Sarcomas

Retroperitoneal soft tissue sarcomas are more common than intraperitoneal sarcomas and must be evaluated carefully; preoperatively for gastrointestinal, genitourinary, vascular, or peripheral nerve involvement.

 

IMAGING AND OTHER STAGING STUDIES

Plain Radiography

 

Plain radiography (FIG 2) is of limited value in the assessment of pelvic girdle lesions. Images often are obscure and confusing.

 

The pelvis, particularly the sacrum, is a difficult structure in which to recognize early bone lesions, and major bone lesions initially may be overlooked. For these reasons, there should be a low threshold for performing further imaging, especially for initial screening and the postoperative evaluation of reconstructions.

 

Computed Tomography and Magnetic Resonance Imaging

 

As a general rule, both computed tomography (CT) and MRI are well indicated for the initial evaluation of most pelvic tumors.

 

CT with intravenous contrast and three-dimensional reconstruction is the optimal technique for assessing the extent of bone involvement and destruction, the osseous anatomy, and the relation between the tumor and the major blood vessels of the pelvis (FIG 3). It is valuable for depicting any distortion of the pelvic anatomy and aiding in the evaluation of the tumor to decide whether it is resectable. Chest CT is essential for staging purposes in evaluation for pulmonary metastases.

 

MRI with contrast is critical for imaging soft tissue (ie, vessels, nerve, muscle) and osseous involvement. MRI is the optimal modality for imaging soft tissue and marrow involvement. It is attractive for assessment of osseous disease and sacral involvement and may be helpful with the serial assessment of neoadjuvant (induction) therapy.

 

Bone Scanning

 

Three-phase bone scan is used to rule out systemic metastasis and to assess the focal osseous involvement and tumor vascularity in the initial flow phase. A decrease in vascularity after induction chemotherapy may indicate response to treatment.

 

Angiography

 

Angiography is mandatory for determining the distal vascular anatomy that often is distorted by large pelvic tumors (FIG 4). It is essential to

determine the level of the various bifurcations preoperatively and to rule out vascular involvement by the tumor. Embolization of the tumor blood supply before surgery is helpful in minimizing blood loss, especially with vascular tumors and tumors with sacral involvement.

 

Venography

 

The pelvic veins always are much larger than their arterial counterparts. Preoperative venography is used to rule out tumor (mural) thrombi, a common finding in chondrosarcomas and osteosarcomas. Their presence may change the planned surgical approach. Postoperative venous Doppler is recommended routinely in all postoperative pelvic resection patients.

 

Fluorine-18 2-fluoro-2-deoxy-D-glucose-Positron Emission Tomography

 

Fluorine-18 2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) may be useful in assessing the “grade” of malignancy, evaluating response to neoadjuvant chemotherapy, and monitoring for local recurrence. Positron emission tomography (PET) combined with CT or MRI is useful for evaluating tumor response. PET-CT scans are useful in early detection of small recurrences. It plays only a minimal role in preoperative planning in determining the extent of surgical resection.

 

Biopsy

 

The purpose of biopsy is to yield a valid tumor diagnosis (benign vs. malignant), tumor grade (high vs. low grade), and tumor subtype (eg, leiomyosarcoma vs. malignant fibrous histiocytoma).

 

Biopsies may be performed by either open or needle technique.

 

Because open biopsy for pelvic tumors is an extensive procedure, needle biopsy—especially CT-guided needle biopsy—is recommended initially for both metastatic and primary pelvic tumors.

 

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FIG 2 • A. Plain radiograph revealing a large lytic lesion (arrowheads) of the right periacetabular region. On the basis of this radiograph, it appears that the cortices are intact. B. Anteroposterior (AP) plain radiograph of the pelvis, read as normal. C. Plain radiograph revealing a cartilage-forming lesion in the left ilium. On the basis of this study alone, it seems that this is an intraosseous lesion. Plain radiographs performed 24 hours after a CT-guided core needle biopsy of a sacral lesion (note the coil; D) and after 6 weeks (E).

 

 

 

 

FIG 3 • A. CT showed extensive bone destruction and extension of the tumor to the pelvis and the right gluteal region. B. CT of the pelvis revealed a large destructive lesion of the sacrum. C. CT shows an extensive tumor on the medial aspect of the ilium with destruction of the inner

table and extension of the pelvis. (A,B: Courtesy of Martin M. Malawer; C: From DeVita VT, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology, ed 5. Philadelphia: Lippincott Williams & Wilkins, 1997:1789-1852.)

 

 

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FIG 4 • Preoperative angiography and embolization of the metastatic lesion shown in FIG 3A. (Courtesy of Martin M. Malawer.)

 

 

Biopsy technique should follow established guidelines for incision placement within the line of eventual resection, minimize contamination of normal tissues (eg, achieve adequate hemostasis at biopsy closure), and retrieve an adequate specimen for frozen section diagnosis. The biopsy should avoid the gluteal and groin areas because they are potential sources for flaps for skin closure after anterior and posterior hemipelvectomy, if necessary.

 

The biopsy incision can also be placed transversely, in the line of the iliac or inguinal incision.

 

Anatomic Considerations

 

Evaluation of the full anatomic extent of a pelvic tumor cannot be based on a single imaging modality. Combined data, gained from two or more imaging modalities, allow a realistic appreciation of the exact anatomic extent. Even when that information is available, however, the full extent of a pelvic tumor often is underestimated preoperatively.

 

Review of any imaging study of the pelvis, because of the numerous anatomic details, must be performed very methodically. The authors review the structures from the back (midsacral region) and follow the pelvic girdle to the front (symphysis pubis), as described in the following paragraphs.

 

Sacrum, Sacral Alae, and Sacroiliac Joint

 

Most patients who undergo extended hemipelvectomy, which necessitates transection of the sacrum through the ipsilateral neural foramina, regain function of the gastrointestinal and genitourinary tracts. Adding a contralateral compromise of the sacral nerve root will create a severe dysfunction. Tumors that penetrate the sacrum and cross the midline are considered unresectable because of the involvement of bilateral sacral nerve roots (FIG 5). The tumor can be resected but the morbidity of bilateral sacral nerve root loss usually outweighs the questionable oncologic benefit from surgery.

 

The common iliac vessels are just anterior to the sacral ala, and any cortical breakthrough by a tumor in that site may be expected to extend directly to the blood vessels. The sacroiliac (SI) joint is a key anatomic landmark. The major nerves and blood vessels are medial to it; therefore, any tumor or pelvic resection lateral to the SI joint may be expected not to violate the major neurovascular bundle. Tumor transgression through the SI joint should be documented prior to surgery by using the combination of CT, MRI, and bone scan.

 

 

 

FIG 5 • High-grade chondrosarcoma of the right sacrum, ilium, and periacetabular region, encasing the ipsilateral sacral foramina. Wide excision would necessitate resection through the contralateral sacral foramina, resulting in an unacceptable functional impairment. (Courtesy of Martin M. Malawer.)

 

Major Pelvic Blood Vessels and Structures

 

The common iliac artery bifurcates along the sacral ala, and the ureter crosses the bifurcation on its ventral side. Large tumors around the sacral ala commonly displace and occasionally invade these structures. The mere presence of major blood vessel or pelvic viscus involvement by tumor is not an indicator of unresectability and demands preoperative planning. If necessary and curative resection is planned, both structures can be excised en bloc with the tumor and then can be repaired with a graft. However, when a complex resection (bony pelvis and viscus resection) is anticipated, the patient must be informed, and surgical assistance and necessary equipment must be prepared in advance.

 

Sacral Plexus

 

Current MRI imaging techniques cannot accurately identify nerve involvement by tumor.

 

Clinical evidence of femoral, sacral, or sciatic nerve dysfunction usually suggests direct tumor involvement. In most cases, the presence and extent of nerve involvement is established only at the time of surgery.

 

Sacral plexus invasion by tumor has the same significance in terms of resectability as tumor invasion of the sacrum; bilateral involvement is an indicator of probable unresectability.

 

Sciatic Notch and Nerve

 

The sciatic notch is the site of pelvic osteotomy in resections of the ilium or periacetabular region and in modified hemipelvectomy. CT establishes tumor extension to the sciatic notch, a tight space through which the sciatic nerve and superior gluteal vessels and nerve pass (FIG 6).

 

The piriformis muscle, which divides the sciatic notch, is a key structure because the sciatic nerve exits the pelvis underneath it and the superior gluteal artery exits the pelvis above it. The patency of the superior and inferior gluteal arteries, which supply the gluteal vasculature, is established by angiography.

 

Adequate blood supply of the gluteal region is a major preoperative consideration in flap design, and the artery must be

 

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preserved in any pelvic resection, if oncologically feasible. The artery is located only a few millimeters from the periosteum of the sciatic notch roof, and it should be dissected carefully.

 

 

 

FIG 6 • The sciatic notch is a tight space through which the sciatic nerve and superior and inferior gluteal vessels and nerves pass. The sciatic nerve exits the notch underneath the piriformis muscle, and the superior gluteal vessels exit the notch above it. (Courtesy of Martin M. Malawer.)

 

Ilium

 

The inner aspect of the bone is covered by the iliacus muscle, which originates from the iliac crest. The iliacus is “pushed” by a growing bone sarcoma and serves as a major barrier to direct extension of tumor to the anatomic structures of the pelvis. Therefore, the iliacus can be used as an oncologic margin for resection.

 

In contrast, metastatic carcinomas to the pelvis tend to invade the covering muscle layer early in their growth stage, and a surgical plane between the tumor and nearby structures cannot be easily defined (FIG 7).

 

Although any pelvic organ can be infiltrated by a tumor, structures that are anterior and posterior to the flare of the muscle (ie, sacral plexus, sciatic notch and nerve, femoral vessels and nerve, bladder, and prostate) are at greater risk for direct tumor extension.

 

Extension to Pelvic Viscera

 

Direct involvement of a pelvic viscus by a pelvic girdle tumor is rare. Left-sided tumors are more likely to involve a component of the gastrointestinal tract because of its close proximity to the pelvic girdle at that point.

 

A rectal tube is inserted preoperatively during any pelvic resection to facilitate identification of the rectum during dissection.

 

Acetabulum and Hip Joint

 

Wide resection of any bone tumor in the periacetabular region, unlike a resection of the ilium or the pubis, imposes a major impairment on the function of the hip joint. It usually necessitates en bloc resection of the proximal femur and a complex prosthetic reconstruction.

 

 

 

FIG 7 • A. The iliacus muscle (arrowheads) is “pushed” by a growing bone sarcoma and serves as a barrier to direct extension of the tumor to the pelvic viscera. High-grade sarcoma of the left ilium “pushing” the iliacus muscle toward the midline. B. Metastatic carcinomas (arrows) to the pelvis tend to invade the covering muscle layer. (Courtesy of Martin M. Malawer.)

 

Pubis

 

The neurovascular bundle passes within the femoral triangle just superficial to the superior pubic ramus. Tumors extending to or arising from the pubic ramus are in close proximity to the femoral artery, vein, and nerve. In addition, the urethra passes straight underneath the symphysis pubis.

 

Vulnerable structures such as a major blood vessel, nerve, or a viscus must be identified and mobilized before resection. By identifying and isolating crucial structures, the surgeon avoids iatrogenic injury during dissection. Establishing the relation of these vulnerable structures to the tumor allows the surgeon to decide whether to proceed with a limbsparing procedure or perform an amputation, make the necessary preparations for a vascular graft (if needed), and perform a safe resection.

 

SURGICAL MANAGEMENT

Preoperative Planning

Restaging Studies

 

Preoperative planning is crucial to obtain an optimal oncologic and functional surgical result.

 

Imaging studies are crucial in addressing the following questions: location and extent of the tumor, the type of pelvic resection that is necessary for adequate removal of the tumor, involvement of critical adjacent structures in the tumor mass (ie, ureter, aorta, inferior vena cava, bladder), and the type of reconstruction that can be achieved.

 

Plain radiographs, CT scans, MRI scans, bone scans, and three dimensional-computed tomography (3-D-CT)

 

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angiographs are obtained to access the extent of osseous and soft tissue involvement in all anatomic planes. The status of crucial adjacent structures—bladder, colon, ureter, inferior vena cava, sacral alar, and possible lumbar extent—is reviewed.

 

Using angiography and venography, preoperative embolization is considered, and anatomic distortion and vessel occlusion and venous thrombus are assessed.

 

Consider the possible need for prophylactic ureteral stents if there is evidence of preoperative ureteral obstruction or displacement.

 

Medical and anesthesia personnel are consulted to assess medical risk, preoperative laboratory studies, and transfusion needs (eg, prepare red blood cell count, cryo, platelets, and plasma). A risk of major blood loss during surgery is assumed, often equal to one total body transfusion (>7% body weight in kilogram).

 

 

Bowel preparation before surgery and intensive care unit (ICU) reservation also should be considered. Orthotic brace is fabricated preoperatively for postoperative use.

 

Colostomy planning and training must be considered if there is left colon involvement or large left-sided pelvic tumors, both of which can be detected preoperatively with contrastenhanced CT and colonoscopy.

 

Appropriate prosthetic implants (eg, total hip replacement vs. saddle prosthesis), bone allograft, or other implants must be ordered.

 

Positioning

 

At the time of surgery, all patients should have a Foley catheter and consider placement of a rectal tube. The rectum may be sutured around the rectal tube to avoid iatrogenic contamination during the operative procedure. During surgery, the surgeon may palpate the balloon of the Foley catheter in the bladder and the rectal tube through the wall of the rectum to assist in proper identification of these structures. This is especially helpful with large pelvic tumors, especially those on the left side.

 

Type I resection (iliac-posterior): The patient is positioned in the lateral decubitus position with an anterior tilt to allow posterior access (FIG 8A-D).

 

Type II resection (periacetabular): The patient is positioned in the lateral decubitus position for access to both the anterior and posterior pelvis (FIG 8E,F).

 

Type III resection (pelvic floor-anterior/obturator ring): The patient is positioned supine with the lower extremity flexed and abducted to provide exposure of the retroperitoneal space, the femoral triangle, the perineum, the symphysis pubis, and the ischiorectal space (FIG 8G-I).

 

 

 

FIG 8 • Type I pelvic (ilium) resection can be either partial (A), in which only part of the ilium is transected, or complete (B). Partial (C) and complete

(D) type I resections. E. Type II pelvic (periacetabular) resections. Reconstruction was performed with a saddle prosthesis. F. Type II pelvic resection. (continued)

 

 

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FIG 8 • (continued) G-I. Type III pelvic (pubic) resection. These resections may include the superior pubic ramus (G), inferior pubic ramus, or both

rami (H). I. Type III pelvic resection.

 

Approach

 

The most useful approach to pelvic biopsy or resection is the utilitarian pelvic incision (FIG 9). All or part of the incision can be used for adequate exploration and resection of the majority of pelvic girdle tumors.

 

The incision begins at the posterior inferior iliac spine and extends along the iliac crest to the anterior superior iliac spine.

 

 

It is separated into two arms: One is carried along the inguinal ligament up to the symphysis pubis; the other turns distally over the anterior thigh for one-third the length of the thigh and then curves laterally just posterior to the shaft of the femur below the greater trochanter and follows the insertion of the gluteus maximus muscle.

 

Reflection of the posterior gluteus maximus flap exposes the retrogluteal space, the proximal third of the femur, the sciatic notch, the sciatic nerve the sacrotuberous and sacrospinous ligaments, the origin of the hamstrings from the ischium, the lateral margin of the sacrum, and the entire buttock.

 

Significant concern exists regarding the possible extracompartmental implantation of tumor cells following biopsy or resection of a pelvic tumor— procedures that are difficult to perform under optimal hemostatic conditions. Unnecessary biopsies must be avoided.

 

If biopsy is indicated, the proper technique and a suitable approach must be chosen. The biopsy tract must be positioned along the line of the future utilitarian incision, remote from the major neurovascular bundle and the abductors.

 

CT-guided core needle biopsy is considered to be an accurate and safe diagnostic tool in the diagnosis of musculoskeletal tumors and is the modality preferred by the authors.

 

The utilitarian incision may be used for hemipelvectomy by continuing the distal portion of the primary incision posteriorly around and behind the thigh and bringing it anteriorly along the inferior pubic ramus to the symphysis, thus encircling the thigh but still allowing the large posterior flap to be used for primary wound closure.

 

Type I Resection: Iliac Resection

 

The incision for an iliac resection is ilioinguinal, following the iliac crest and curving posteriorly at the level of the SI joint.

 

It then follows the length of the SI joint combined with a lateral incision to expose the outer portion of the ilium, sciatic notch, and retrogluteal space.

 

Type II Resection: Periacetabular Resection

 

A combination of an anterior retroperitoneal approach and lateral anterior incision along the femur that curves posteriorly is used for a periacetabular resection.

 

A lateral, posterior-based fasciocutaneous flap, called a gluteal flap, is then raised. This permits easy access and visualization of the retrogluteal space: hip joint, sciatic notch, sciatic nerve, and ischium as well as the supra-acetabular area needed for the superior osteotomy.

 

 

 

FIG 9 • The utilitarian pelvic incision. (Courtesy of Martin M. Malawer.)

 

 

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Type III Resection: Pelvic Floor and Pubic Region

 

Three incisions are required for a resection of the pelvic floor and pubic region.

 

 

The main incision is the retroperitoneal (ilioinguinal) incision to permit retroperitoneal exploration and mobilization of the major vessels and nerves.

 

Two longitudinal incisions are required to develop a distal-based flap of the anterior thigh so as to expose the femoral triangle as well as the adductors attaching to the obturator foramen.

 

One incision follows the perineal crease; the second begins at the lateral portion of the ilioinguinal incision at the level of the anterior superior iliac spine.

 

TECHNIQUES

• Type I: Iliac Posterior Resection

The patient is placed in the lateral decubitus position with a posterior tilt.

The utilitarian pelvic incision is used. Its ilioinguinal component is advanced medially to the symphysis pubis, and its posterior arm is brought to the level of the SI joint (TECH FIG 1A,B).

All muscle attachments, with the exception of the iliacus and gluteus minimus and portions of the gluteus medius, which are resected en bloc with the tumor, are removed from the iliac crest. The abdominal wall musculature, the sartorius muscle, and the tensor fasciae latae muscles are transected from the iliac crest and reflected away from the ilium. The rectus femoris muscle remains intact. The iliotibial band is transected from its origin from the iliac crest and reflected posteriorly along with the gluteus maximus. Large fasciocutaneous flaps are raised and reflected medially and posteriorly.

The plane between the iliacus and the psoas muscle is developed cautiously because the femoral nerve lies in that space. The psoas muscle and the femoral nerve are reflected medially, and the iliacus muscle is transected through its substance (TECH FIG 1C).

The external iliac artery, which lies against the lower margin of the ilium, gives off no major branches along the inner table of the ilium; ligation of large blood vessels is not required, therefore, in type I pelvic resection. Most tumors of the ilium break through the outer table and

 

push the gluteus medius muscle laterally. The gluteus medius muscle is transected through its substance, 2 to 3 cm distal to the inferior border of the tumor (TECH FIG 1D,E). It is important to try to save as much muscle belly as possible because that will be the major component in soft tissue coverage of the pelvic content and will be necessary for reconstruction of the abductor mechanism.

 

Osteotomy of the ilium is performed using a malleable retractor, which is inserted through the greater sciatic notch, along the inferior border of the inner table, and out just underneath the anterior superior iliac spine, to protect the pelvic viscera (TECH FIG 1F). The ilium is transected as shown by the dotted line in the figure,

 

 

P.207 P.208

leaving the origin of the rectus femoris muscle and the roof of the acetabulum intact. Osteotomy of the posterior aspect of the ilium is then performed; a malleable retractor is positioned through the greater sciatic notch, along the posterior border of the ilium, and parallel to the ipsilateral sacral ala (TECH FIG 1F, inset).

 

 

 

TECH FIG 1 • A. Incision and surgical approach. The entire utilitarian incision is used for type I resection. The posterior fasciocutaneous flap exposes the entire retrogluteal area: the sciatic notch, the sciatic nerve, the abductor muscles, and the hip joint. This approach provides a good exposure of the retroperitoneal space as well as the posterior retrogluteal area and permits a safe resection of the ilium. B. The ilioinguinal component is advanced medially to the symphysis pubis and posteriorly to the sacrum. (continued)

 

 

TECH FIG 1 • (continued) C. Posterior exposure and muscle releases. The abdominal wall musculature is transected off of the iliac crest. The sartorius and tensor fasciae latae muscles are transected from their tendinous insertions and reflected distally. The rectus femoris muscle remains intact. Large fasciocutaneous flaps are raised and reflected medially and posteriorly. The iliotibial band is transected from its origin from the iliac crest and reflected posteriorly along with the gluteus maximus. D. Anterior (retroperitoneal) exposure. The retroperitoneal space is easily exposed and explored through the ilioinguinal component of the incision. The plane between the iliacus and the psoas muscle is developed with caution because the femoral nerve lies in that space. The psoas muscle and the femoral nerve are reflected medially, and the iliacus muscle is transected through its substance. The femoral nerve is preserved. E. Posterior exposure and release of gluteal muscles. The retrogluteal area is exposed. The gluteus maximus muscle is released from the iliotibial band and from the femur and reflected posteriorly. The sciatic nerve is identified and preserved. All of the remaining abdominal muscles are released from the wing of the ilium. The gluteus medius muscle is transected through its substance, 2 to 3 cm distal to the inferior border of the tumor. It is important to try to save as much muscle belly as possible. F. Supra-acetabular osteotomy and SI disarticulation. A malleable retractor is inserted through the greater sciatic notch, along the inferior border of the inner table, and out just underneath the anterior superior iliac spine to protect the pelvic viscera. The ilium is transected above the hip capsule, leaving the origin of the rectus femoris muscle and the roof of the acetabulum intact. Care is taken not to enter the hip joint. Inset: The SI joint is opened from within the pelvis. The iliac vessels must be mobilized and retracted before attempting to open the SI joint. (continued)

 

 

TECH FIG 1 • (continued) G. Soft tissue reconstruction. The gluteus medius muscle is sutured to the abdominal wall musculature with the ipsilateral lower extremity in abduction. Dacron tape must be used to reinforce this reconstruction. The suture line also is reinforced by oversewing the tensor fascia lata and sartorius muscles. (Courtesy of Martin M. Malawer.)

 

The most important component of soft tissue reconstruction is the attachment of the proximal rim of the gluteus medius muscle to the abdominal wall musculature. Even if the entire gluteus medius muscle was spared, the attachment of these two muscle groups, which are not anatomically connected, creates a significant tension, which can be reduced by placing the lower extremity in abduction. The suture line is reinforced with the tensor fasciae latae and sartorius muscles with 3-mm Dacron tape (TECH FIG 1G). Closure of the muscle layer must be meticulous because poor healing and wound dehiscence will expose the abdominal and pelvic contents and will be difficult to manage.

Optional Reconstruction

 

It is not necessary to reconstruct the resultant bony defect, although allograft reconstruction has been reported.

 

For iliac osseous reconstruction, allograft should be thawed with permanent/tissue culture. Gram stain has a high rate of false positives and should be avoided.

 

Cut the allograft after careful sizing and orientation and fix with a 4.5-mm reconstruction plate. Use intraoperative radiographs to confirm screw placement.

 

Two deep soft drains (anterior and posterior) are placed deep to the fascial closure.

• Type II: Periacetabular Resection

   

  The patient is in the lateral decubitus position with posterior tilt to maximize anterior dissection.

   

  The utilitarian incision is used to expose both the anterior (internal) and posterior (extrapelvic) aspects of the pelvis. The ilioinguinal incision is used to develop the retroperitoneal plane, and the posterior gluteus maximus fasciocutaneous flap is used to develop the retrogluteal space.

   

  The iliac vessels are mobilized first, and the hypogastric artery is identified and ligated. The sciatic and femoral nerves are identified and protected.

   

  The level of osteotomy through the ilium is identified from within the pelvis, as are the superior pubic rami. Identification of the superior pubic rami requires mobilization of the external iliac and femoral vessels as they cross the ramus (TECH FIG 2).

   

  A large posterior myocutaneous flap is developed with the gluteus maximus muscle. The gluteus maximus muscle is detached from the iliotibial band and femur to enable it to be retracted posteriorly. This exposes the retrogluteal space: the ilium, sciatic notch, sciatic nerve, and hip joint.

   

  The ischium is identified through the posterior incision and is osteotomized above the level of the biceps femoris tendon insertion.

   

  Complete removal of the periacetabulum requires release of the sacrospinous ligament and some of the pelvic floor musculature. An ilioinguinal incision is used with a separate posterolateral hip incision for hip exposure and replacement, posterior column osteotomy, and exposure of the sciatic nerve.

   

  Three types of osteotomies may be used for periacetabular resection: supra-acetabular osteotomy, superior pubic ramus osteotomy, or ischial osteotomy.

   

  A total hip exposure is used to identify the sciatic nerve and posterior column. The procedure is begun with dissection of the external rotators

  and osteotomy of the femoral neck per total hip procedure.

   

  Cut the femoral neck at the standard neck length (1.0 cm proximal to the lesser trochanter).

   

  Incise the hip capsule peripherally with dissection of the sciatic nerve proximally to the sciatic notch.

   

  The anterior and posterior columns are exposed to allow osteotomy of the acetabulum. Supra-acetabular and ischial osteotomy requires careful exposure and retraction of the sciatic nerve and gluteal vessels.

  Composite Allograft Acetabular Reconstruction after Type II Resection

   

  Several choices are available for reconstruction following a type II resection: composite allograft, saddle reconstruction (The Link Prosthesis, LINK® Endo-Model® Saddle Prosthesis Rockaway, NJ), partial pelvic prosthesis (Stryker Periacetabular Reconstruction Prosthesis [PAR], Mahwah, NJ), various reconstruction rings with large phalanges, and ischiofemoral arthrodesis. Each has unique techniques, complications, functional deficits, and results.

   

  P.209

   

   

   

  TECH FIG 2 • A. Plain radiograph showing an extremely high-grade malignant fibrous histiocytoma arising from the superior and inferior pubic ramus involving the entire obturator foramen, pelvic floor, and medial and supra-acetabular aspect of the acetabulum (solid arrows). B. Gross specimen following type II or type III pelvic resection. C. Gross specimen following a complete internal hemipelvectomy (type I/type II/type III pelvic resection). D. Radiograph of the resected specimen showing complete involvement of the hemipelvis. The defect superiorly was created by an open biopsy. E. Gross specimen of a combination type II or type III pelvic resection. F. Gross specimen following a type III pelvic resection. A large tumor mass is seen arising from the obturator internus muscle (solid arrows). IL, portion of the ilium; A, acetabulum; P, the entire pelvic floor, including the superior and inferior pubic ramus; SP, superior pubic ramus; IP, inferior pubic ramus and pubis; SY, symphysis pubis. (Courtesy of Martin M. Malawer.)

   

  Femoral component: Ream and place the uncemented femoral component through the posterior lateral approach before proceeding with iliac osteotomy resection.

   

  Acetabulum: Ream the allograft for the acetabular component and place the acetabular component (cement and screws) into the allograft to confirm graft and acetabular orientation in situ with radiography before screw or cement fixation.

   

  Check acetabulum positioning with radiographs before and after fixation or cementation. Orient the iliac graft before confirming the acetabular orientation, and fix the graft with a reconstruction plate and screws. Use an extended polyethylene acetabular rim, and consider a large femoral head (32 to 36 mm) to improve postoperative stability.

   

  Closure: Using the inguinal ligaments, reconstruct the abductors, especially if a trochanteric osteotomy was done. Perform pelvic closure at the iliac crest and inguinal canal with wound drainage catheters.

• Type II: Resection and Reconstruction with Saddle Prosthesis

  Notchplasty

   

  A notch is created in the remaining ilium using a high-speed burr.

   

  The notch should be placed in the thickest region of the remaining bone (usually medial) (TECH FIG 3A-C). Preparation of the Proximal Femur

   

  The proximal femur is prepared as for a standard femoral component.

   

  The intramedullary canal of the proximal femur is reamed to accept the largest diameter stem and allow for a 2-mm circumferential cement mantle.

   

  Once reaming is completed and the appropriately sized stem (diameter and length) is selected, a distal femoral cement plug is inserted to a depth of 2 cm below the tip of the selected femoral stem.

   

  The femoral canal then is irrigated with saline and packed with gauze. Once the cement (polymethylmethacrylate) is prepared, the gauze is

  removed, and the femoral prosthesis is cemented within the proximal femur.

  Trial Reduction

   

  A reduction using trial components is critical in assessing accurate length of the base component (intercalary segment) and determining optimum soft tissue tension (TECH FIG 3D-K). The base component length should be determined by the distance between the ilium and femoral neck cuts because the

   

  P.210

  length indicated on the base component is the total length from the notch of the saddle to the femoral collar. The base component should be selected so that reduction is barely possible and there is minimum “play” in the reduced joint. The surgeon should be able to reattach the abductor mechanism to its anatomic position on the osteotomized greater trochanter.

   

  A trial reduction also can determine areas where the saddle component may impinge on the existing notch during intraoperative range of motion. These areas can be further contoured with a high-speed burr to prevent impingement, which may result in limited motion or dislocation. Hip motion (flexion to at least 90 degrees, extension to 30 degrees, abduction to 45 degrees, adduction to neutral, and rotation) should be possible without evidence of impingement or dislocation.

  Abductor Mechanism Reconstruction

   

  The osteotomized greater trochanter and abductors are reattached to their original location using cables. If the greater trochanter was included in the resected specimen, the abductor mechanism is reattached to the prosthesis using 3-mm Dacron tapes or a cable system. Soft tissue tension and prosthetic stability are again tested once the abductor mechanism reconstruction is complete. The piriformis and short external rotator muscles are brought forward and reattached to the proximal femur (or prosthesis). The gluteus maximus muscle is then reattached to its insertion using nonabsorbable suture (TECH FIG 3L-N).

   

  Pelvic closure involves attachment of the inguinal canal and abdominal wall to the symphysis pubis and lateral iliac crest. Soft tissue tension and prosthetic stability are tested again once the abductor mechanism reconstruction is complete. The piriformis and short external rotator muscles are brought forward and reattached to the proximal femur (or prosthesis). The gluteus maximus is then reattached to its insertion using nonabsorbable suture.

   

  For high type II pelvic resections, reconstruction should be carried out with a partial pelvic prosthesis.

   

   

   

  TECH FIG 3 • A. Photograph following a periacetabular resection showing the remaining ilium (IL), the sciatic nerve (S), the greater trochanteric osteotomy (G), and the femoral head. B. Creation of the deep notch (large arrows). C. Reduction of the saddle prosthesis into the iliac notch (IL). The notch (solid arrows) must be as deep as the saddle and permit approximately 45 degrees of flexion and extension as well as abduction and adduction. D. Surgical exposure using the utilitarian pelvic incision. E. A large posterior fasciocutaneous flap based medially permits the release of the gluteus maximus. (continued)

   

   

  P.211

   

   

  TECH FIG 3 • (continued) F. Schematic diagram of the mobilization of the periacetabular structures and the three osteotomies that are necessary for a complete resection of the acetabulum. G. Schematic of the “close-up” view of the superior pubic ramus osteotomy. H. The infra-acetabular osteotomy. I. A notch is made in the supra-acetabular roof or remaining ilium for the saddle prosthesis to sit in. J. Saddle prosthesis reduced into the notch. K. Schematic diagram of the saddle prosthesis following a periacetabular resection for sarcoma and radical curettage for a large acetabular metastasis. Postoperative radiographs and CT scans demonstrating common postoperative radiographic findings. (continued)

   

   

  P.212

   

   

   

  TECH FIG 3 • (continued) L. Anteroposterior (AP) radiograph of the pelvis with a saddle prosthesis in place. M. A 45-degree oblique radiograph of the affected side of the pelvis. N. CT scan showing a typical saddle prosthesis in good position. G, gluteal muscles; S, sciatic nerve; IC, iliacus muscle; AB, abductor muscles. (A-C,L-N: Courtesy of Martin M. Malawer; D-K: From Malawer M. Reconstruction following resection of primary periacetabular tumors. Semin Arthroplasty 1999;10:171-179.)

• Type III Resection: Pelvic Floor/Anterior Obturator Ring

   

   

  A utilitarian pelvic incision with a perineal extension is used (three-incision approach). The patient is positioned with the ipsilateral hip slightly elevated.

   

  The ilioinguinal component of the utilitarian pelvic incision with a lateral and perineal (medial) extension is used (see TECH FIG 1G). This

  incision allows exposure and mobilization of the femoral vessels and nerve through a distal-based anterior flap.

   

  Perineal extension of the incision is used to expose the ischium, which is resected through the ischiorectal fossa when the resection is performed for a large pubic lesion.

   

  Large myocutaneous flaps are raised. The spermatic cord is reflected medially. The inguinal ligament is transected from its pubic insertion and reflected laterally.

   

  The neurovascular bundle (ie, the femoral artery, vein, and nerve) is retracted laterally, exposing the origin of the adductor magnus and pectineus muscles, which is transected off the pubis and reflected distally.

   

  Using the lateral component of the incision, the origins of the hamstrings, adductors, and gracilis are transected off the ischium and reflected distally (TECH FIG 4).

   

  The first malleable retractor is placed behind the symphysis pubis in front of the bladder. The second malleable retractor is placed behind the superior pubic ramus and in front of the inferior pubic ramus, medial or lateral to the ischium, depending on the required oncologic margins (TECH FIG 4C).

   

  Osteotomy through the symphysis pubis and pubic rami is performed. It is important to smooth the sharp bony edges, especially those that lie against the bladder.

   

  Surgical wounds around the groin are notoriously associated with a high incidence of dehiscence and infection. Meticulous wound closure with adequate drainage is, therefore, mandatory. Continuous suction is required for 3 to 5 days. Perioperative intravenous antibiotics are continued until the drainage tubes are removed.

   

  Postoperative mobilization with weight bearing as tolerated is allowed.

   

  Rarely, reconstruction of the pelvic floor with Marlex (CR Bard, Cranston, RI) mesh is required.

   

   

   

  TECH FIG 4 • A. The ilioinguinal component of the utilitarian pelvic incision with a modified perineal extension are used. (continued)

   

   

  P.213

   

   

  TECH FIG 4 • (continued) B. Schematic of the three osteotomies required to remove the pelvic floor. C. Transection of the symphysis pubis, superior pubic ramus, and ischial osteotomy. (Courtesy of Martin M. Malawer.)

• Type IV Resection: Hemipelvic

 

Table 1 describes hemipelvic resection along with other techniques.

 

Combined, extended full pelvic dissection from symphysis pubis to SI joint is required.

 

Complete dissection of the sciatic notch, the hip joint, the sciatic nerve, and the femoral vessels is required.

 

Pelvic reconstruction is more challenging because of the need for fixation at the sacrum and symphysis pubis and the difficulty in orienting a pelvic graft.

 

 

Some surgeons do not recommend reconstruction but accept 3 inches of shortening and the use of a pelvic long-leg brace. A large amount of intraoperative blood loss and hemipelvic graft fixations present significant surgical challenges.

 

P.214

 

Table 1 Summary of Pelvic Resection and Reconstruction Techniques
Surgical Technique	Position	Incision	Exposure	Vessels and Nerves	Resection	Reconstruction	Closure
Type II:	Lateral	Ilioinguinal	External oblique	Careful	Iliopsoas,	Allograft	Abdominal wall
posterior iliac	with	with or	and abdominal m.	dissection	osteotomy	fixation with	m. to pelvis
resection	anterior	without		of femoral	at iliac crest	4.5-mm plate	with
	tilt	sacral		n. and			nonabsorbable
		extension		vessels;			sutures and
				iliac,			two deep
				gluteal			drains
				vessels			(anterior and
							posterior)

 

Type II: lateral acetabular resection

Straight lateral

Ilioinguinal with separate posterior lateral hip incision

External oblique off superficial lateral crest m., expose hip

External iliac a. and v., obturator n., gluteal vessels, sciatic n.

Hip joint, sciatic notch, external rotators, femoral neck osteotomy

Ream allograft for acetabular placement; cement and screw with 4.5-mm plate

Attach inguinal canal and abdominal wall to symphysis pubis and lateral iliac crest

 

Type III: anterior obturator

Supine Ilioinguinal incision with anterolateral extension

Symphysis pubis to posterior lateral iliac crest

Femoral sheath, lateral femoral cutaneous n., obturator n., a., v.

Between inferior pubic ramus and ischium, depending on tumor location

Soft tissue with Martex/fascia allograft or Gore-Tex if acetabular anterior column intact. If not intact, then bony obturator allograft

Inguinal canal with nonabsorbable sutures and deep drains; prevent inguinal hernia

 

Hemipelvic Lateral Ilioinguinal Symphysis to

lateral crest and external iliac m.

External iliac

Iliac and hip, with or without obturator

Allograft verse saddle prosthesis

Lateral crest and ilioinguinal canal

 

Gluteal Prone Posterior gluteal

Gluteal m. Sciatic n., gluteal n., v., a.

Deep proximal posterior greater trochanter, if inferior to notch

 

 

Retroperitoneal (soft tissue)

 

Supine Symphysis to

posterolateral ilium

 

Midline if bowel is involved.

Abdominal/external oblique off iliac crest

 

Iliac and gluteal vessels, ureter, femoral vessels and nerve, sciatic n.

 

Usually respects iliopsoas musculature

 

External oblique abdominal wall reattached to pelvic brim

 

Reattach external oblique to pelvic brim

 

Inguinal groin Supine Pubic

tubercle to lateral iliac crest

Inguinal cord, umbilical

Femoral sheath, inferior epigastric vessels

Inguinal canal

Inguinal ligament

 

 

PEARLS AND PITFALLS

Vascular problems ▪ Always have vascular control of the major vessels proximally and distally, both arterial and venous, especially common, internal, and external iliac vessels.

Intraoperative

bleeding

• Severe bleeding usually occurs with venous, not arterial, injuries. Suture and ligate all serious bleeders.

Thrombosis

• All patients are at risk to develop an arterial venous thrombosis during or after surgery and should be evaluated (pulses) carefully during and for the first 72 hours. Always

confirm adequacy of hemostasis and distal flow and pulses before leaving the operating room. If there is any question, perform an intraoperative or postoperative angiogram.

Postoperative

bleeding and

• If bleeding continues, and coagulation factors rule out disseminated intravascular coagulation, strongly consider taking the patient back to the operating room.

Alternatively, perform an angiogram with attempt at embolization of the bleeding vessel. The degree and timing of the bleeding are important in determining the correct

 

coagulopathy

course of action.

• If massive (>4.0-5.0 L) bleeding occurs during the dissection, pack the wound with local pressure until the patient's blood pressure stabilizes.

• Check prothrombin time, partial thromboplastin time, and platelet counts intraoperatively and every 6 hours for 24-48 hours.

• Almost all patients need intensive monitoring following surgery.

Hypocalcemia and ▪ Calcium (Ca) always is required intraoperatively. Check the Ca level in the operating room and postoperatively.

hypomagnesemia ▪ Magnesium (Mg) loss is very common following a major bleed, especially in patients treated with induction chemotherapy. The agent that most commonly causes Mg loss is cisplatinum. Patients receiving this form of chemotherapy routinely require a large amount of Mg postoperatively. If left uncorrected, cardiac arrest may occur.

Nerve injuries

• Iatrogenic injury may occur to femoral, sciatic, or sacral nerve roots. Injury occurs during dissection (neurapraxia) or sacral screw fixation. Obturator nerve sacrifice is not

a significant functional loss.

Ureter and bladder ▪ Consider a preoperative ureteral stent for all large tumors. Foley catheter placement enables palpation of the bladder intraoperatively.

injuries ▪ Repair bladder wall injuries in two or three layers. Check carefully for bladder injury if hematuria or oliguria occurs intraoperatively.

Hip

• Check hip radiographically for stability prior to and after wound closure.

General

• Remember that the first step in avoiding injury to the critical structures mentioned is taking the time to identify and tag all of them initially during dissection.

 

 

 

 

POSTOPERATIVE CARE

P.215

 

The distal extremity pulses are checked immediately after surgery and every hour for the first 24 hours. Late arterial thrombosis often is due to intimal injuries.

 

Persistent wound drainage usually is due to a large retroperitoneal collection. If the wound continues to drain after 4 to 7 days postoperatively, wound irrigation and drainage in the operating room should be considered.

 

All postoperative patients should have a pelvic radiograph once a week for the first 2 weeks.

 

After initial postoperative stabilization, postoperative complete blood cell count and laboratory studies daily should be checked for the first week then twice per week.

 

Postoperative mobilization is highly individualized:

 

 

In type I resection, abdominal wall to abductors are maintained in abduction for 7 days in bed and then in a pelvic-thigh brace that avoids excessive adduction.

 

Type II resection and reconstruction is very variable. Patients with a saddle prosthesis and composite allograft are maintained on partial weight bearing for 3 to 6 months and need a pelvic and thigh brace for 2 to 3 months.

 

Patients with a type III resection with or without Marlex reconstruction are kept in bed with the lower extremity in neutral (it is necessary to avoid abduction) to avoid a perineal incision dehiscence. A pelvic and thigh orthosis is used for about 3 months. Full weight bearing can be initiated early if the medial wall of the acetabulum was not involved.

 

 

COMPLICATIONS

Early

Bleeding: Most problems with intraoperative bleeding occur with venous, not arterial, bleeding. Coagulopathy and the need for large blood transfusions are common complications. Coagulation factors, Ca, and Mg should be monitored. Patients should receive packed cells, fresh frozen plasma, platelets, Ca, and Mg as necessary during and after surgery. Patients with (>500 mL per hour per 3 hours) blood loss in the immediate postoperative interval should be considered for postoperative embolization to control blood loss.

Arterial thrombosis occurs due to intimal flap tear and should be monitored by distal pulse measurement with Doppler, every hour for the first 24 hours. If arterial thrombosis occurs, immediate thrombectomy is required.

Nerve: Postoperative femoral or sciatic neurapraxia are common and should be observed.

Ureter/bladder: Patients should be evaluated for intraoperative hematuria or oliguria, which may suggest bladder or ureter injury. Urine output is routinely measured hourly during surgery. The Foley urinary catheter is kept in place for 4 to 7 days. Urethral injuries are diagnosed postoperatively by retrograde cystogram and require surgical treatment.

Bowel injuries require repair or resection and possible colostomy.

Major ileus is a common problem following extensive pelvic surgery. The postoperative patient should have nothing by mouth until bowel injury recovers (with a nasogastric tube in place) until appropriate bowel sounds return (usually 3 to 4 days).

Late Complications

Infection: Deep infection develops in 20% to 30% of patients following pelvic surgery. If such an infection occurs, the patient must be taken back to the operating room, and removal of the prosthesis and allograft must be considered.

Dislocation: The dislocation rate for a saddle prosthesis is 5% to 10%. This rate may be even higher for “composite” reconstructions. Failure of the allograft may take the form of fracture through the allograft or failure of fixation.

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Prosthesis failure includes failure of the reconstruction ring, acetabular cap, screws, and plate.

Morbidity and mortality after pelvic resection remains high. Hemipelvectomy may be required due to local recurrence, infection, or uncontrolled bleeding.

 

 

SUGGESTED READINGS

1. Aboulafia AJ, Buch R, Mathews J, et al. Reconstruction using the saddle prosthesis following excision of primary and metastatic periacetabular tumors. Clin Orthop Relat Res 1995;(314):203-213.

    

    

2. Aljassir F, Beadel GP, Turcotte RE, et al. Outcome after pelvic sarcoma resection reconstructed with saddle prosthesis. Clin Orthop Relat Res 2005;438:36-41.

    

    

3. Cottias P, Jeanrot C, Vinh TS, et al. Complications and functional evaluation of 17 saddle prostheses for resection of periacetabular tumors. J Surg Oncol 2001;78:90-100.

    

    

4. Enneking WF, Dunham WK. Resection and reconstruction for primary neoplasms involving the innominate bone. J Bone Joint Surg Am 1978;60:731-746.

    

    

5. Hillmann A, Hoffmann C, Gosheger G, et al. Tumors of the pelvis: complications after reconstruction. Arch Orthop Trauma Surg 2003;123:340-344.

    

    

6. Ozaki T, Hoffmann C, Hillmann A, et al. Implantation of hemipelvic prosthesis after resection of sarcoma. Clin Orthop Relat Res 2002; (396):197-205.

    

    

7. Renard AJ, Veth RP, Schreuder HW, et al. The saddle prosthesis in pelvic primary and secondary musculoskeletal tumors: functional results at several postoperative intervals. Arch Orthop Trauma Surg 2000;120:188-194.

    

    

8. Shin KH, Rougraff BT, Simon MA. Oncologic outcomes of primary bone sarcomas of the pelvis. Clin Orthop Relat Res 1994;(304):207-217.

    

    

9. Wirbel RJ, Schulte M, Mutschler WE. Surgical treatment of pelvic sarcomas: oncologic and functional outcome. Clin Orthop Relat Res 2001; (390):190-205.