Surgery of the Cervical Spine

Anterior approach to the cervical‌

spine (C3-T1) 25

Posterior approach to the cervical

spine (C2-C7) 31

Posterior approach to the upper

cervical spine (C1-C2) 35

Halo vest fixation of the cervical spine 36

Viva questions 41

 

Cervical spine	Clinical range of motion	Radiological upper spine (C1-C2) range of motion	Radiological lower spine (C3-C7) range of motion
Flexion	45°	15°	40°
Extension	55°	15°	25°
Lateral bending	40°	0°	50°
Axial rotation	70°	40°	45°

 

 

Position of arthrodesis

• Maintain the sagittal contour (lordosis) and avoid local kyphosis.

• During anterior interbody fusion surgery, the graft or artificial cage selected is wedge shaped with greater anterior vertebral height.

• The rods are contoured into lordotic shape during posterior fusion/stabilisation

procedures.

 

Anterior approach to the cervical spine (C3-T1)

Preoperative planning

Indications

• Anterior decompression for spinal canal or foraminal stenosis

  • Presenting symptoms – myelopathy, radiculopathy, neurological deficit

  • Herniated disc from degenerative or traumatic causes

     

  • Osteophytes

  • Bony element (traumatic causes)

  • Subluxation of the vertebra due to degenerative process

  • Tumour

  • Infection

  • Congenitally narrow canal

  • Ossification of posterior longitudinal ligament

• Anterior intervertebral fusion

  • Degenerative pathology

  • After anterior decompression for indications listed previously

• Anterior stabilisation

  • Trauma

  • Degenerative subluxation

  • After decompression/fusion

• Cervical disc replacement

  • Degenerative disc disorders

• Biopsy/excision/drainage of collection

  • Tumour

  • Infection

     

     

    Consent and risks

• Dysphagia: 50% in short term; 10% long term (more common in multilevel surgery, longer retraction time, older patients). This complication can be reduced by keeping retraction time to a minimum, using smooth contour retractors, lower profile plate, good tissue handling and haemostasis.

• Recurrent laryngeal nerve injury: 0.2%; it produces paralysis of one side of the vocal

  cord, and leads to hoarseness of the voice, airway problems and aspiration. This is more common in the right-sided approach. The reason for its vulnerability on the right side is because of its course, as it crosses from lateral towards the trachea in the midline, in the lower part of the neck. Some consider it to occur due to the dual compression of the nerve from the self-retaining deep retractor on the lateral aspect and medially by the cuff of the endotracheal tube within the trachea. This can be avoided by relaxing the retractor often and deflating and reinflating the cuff after application of the retractor.

• Other neurological injuries: Superior laryngeal nerve, hypoglossal nerve, sympathetic

  nerve and stellate ganglion causing Horner’s syndrome.

• Spinal cord injury.

• Vascular injury: Inferior thyroid artery, common carotid artery, vertebral artery, internal jugular vein.

• Haematoma.

• Visceral injury: Oesophagus, trachea.

• Infection: 0.5%.

• Cerebrospinal fluid (CSF) leak and fistula: 0.1%.

• Death: 0.1%.

   

  Risks for fusion/stabilisation

  • Bone graft donor site morbidity

  • Non-union/pseudarthrosis: 4%–20% in single-level fusion, 25%–50% in multilevel fusion

  • Implant pull out/failure

  • Anterior graft migration

   

   

  Operative planning

  An image intensifier should be available from the start of the procedure. If an operative microscope is to be used it should be pre-booked. Some prefer to use magnification loupes, along with headlights for improved illumination of the operative field.

  All radiological investigations should be available. Check/pre-order the specific implants and instrumentation.

  If iliac bone crest graft is required, then the side and draping need to be pre-planned; a tri-cortical graft is best. In high-risk cases, the spinal cord integrity is monitored intraoperatively using evoked potentials (somatosensory or motor), and this needs to be organized.

   

  Anaesthesia and positioning

  The operation is performed under general anaesthesia. The head end of the patient is positioned opposite to the anaesthetist; therefore, long tubing is needed which must be safely placed and well secured. The outer end of the endotracheal tube is positioned and fixed away from the side of the incision. Prophylactic antibiotics are given as per protocol.

  Place the patient in a supine position on the operating table with or without Mayfield skull clamp attachment. Head ring and adhesive tape are used to position the head securely if the Mayfield clamp is not used. The Mayfield skull clamp attachment provides a three-point rigid cranial fixation and allows greater flexibility in positioning of the cervical spine and better visualisation during imaging. It is particularly useful in surgery for cervical spine fracture. It enables better control of cervical spine position and allows change in position and manipulation during the surgical procedure.

  A rolled-up pad or saline bag or sandbag is placed between the scapulae to enable slight extension of the cervical spine as desired. The head end of the table is tilted up to minimise venous bleeding. The foot end of the bed may need levelling to prevent migration of the patient down the bed. To enable adequate visualisation of the lower cervical spine image intensifier and for improved access, broad strips (10 or 15 cm [4 or 6 inches]) of adhesive are used to pull the shoulders down and anchor them to the operation table.

  The accessibility of the image intensifier and the ability to visualise the required field must be checked. The positioning of the image intensifier and the microscope during the procedure needs to be planned.

   

  Surgical technique

  Choosing the side for the approach

  For the upper and middle cervical spine, the right- or left-sided approach can be used. The right-sided approach is usually preferred by the right-hand dominant surgeon and vice versa. The site of the pathology (e.g. in tumour) can sometimes influence the choice.

  For the lower cervical spine (C6 and below), some prefer the left-sided approach, because of the increased risk of injury to the recurrent laryngeal nerve injury with the right-sided approach.

  If previous surgery has been carried out on one side of the neck, the vocal cord function must be checked before considering operating on the opposite side.

   

  Choosing the incision

  Depending on the number of vertebral levels to be exposed, the incision can be transverse, oblique or longitudinal. The transverse approach is most commonly used and can give access to up to three vertebral body levels, although for more extensive oncological approaches an expansile longitudinal approach along the anterior border of sternocleidomastoid may be used.

  The cosmetic appearance is better with transverse and mild oblique incision along the neck’s skin creases/cleavage lines.

   

  Landmarks

  Few palpable structures in the anterior aspect of the neck give an approximate estimation of the vertebral level and incision (Figure 3.1). It is common practice to use an image intensifier to identify the level of the incision, and the incision site is marked.

  The following guidelines can be applied for the transverse incision for the approaches to the following vertebral levels:

   

• C3 and C4 level – level of the hyoid bone or two finger breaths below the mandible

• C4 and C5 level – level of the thyroid cartilage

• C5 and C6 level – level of the cricoid cartilage

• C6 and below – two finger breadths above the clavicle

 

The anterior border of the sternocleidomastoid muscle and the midline are identified and marked.

 

Incision

The skin incision extends from the anterior border of the sternocleidomastoid muscle to the midline, extending further if necessary.

 

C1/2 C3/4 C4/5

C5/6

C6/7

C7/T1

Lower border

of mandible Hyoid bone

Thyroid cartilage Cricoid ring

Sternocleidomastoid

 

 

 

Figure 3.1 Anatomical landmarks and levels in the anterior approach to the cervical spine.

 

Superficial dissection

 

Structures at risk

• Longitudinal and traversing veins in deep cervical fascia

• Inferior thyroid artery

• Carotid sheath (enveloping the common carotid artery, internal jugular vein and vagus nerve)

• Trachea and oesophagus

• Recurrent laryngeal nerve and superior laryngeal nerve

 

 

The platysma muscle is cut in the same direction as the skin incision or split longitudinally along its fibres. The platysma is supplied by the cervical branch of the facial nerve, and it receives its branches in the mandibular region, superior to the incision site. However, dividing the platysma does not cause any significant morbidity.

The anterior border of the sternocleidomastoid is identified, and the deep cervical fascia is incised medially. The longitudinal and traversing vein may need retraction or ligation. The sternocleidomastoid muscle is gently retracted laterally, and the strap muscles and thyroid gland are retracted medially. The superior belly of the omohyoid muscle can be divided if it traverses the operating field or if an extensive approach is required.

 

This dissection exposes the carotid sheath and the pretracheal fascia (Figure 3.2). The carotid pulse is palpated and the pretracheal fascia incised medial to the carotid sheath using blunt dissection (peanut surgical swab). The carotid sheath enveloping the common carotid artery, internal jugular vein and vagus nerve are retracted laterally and the trachea and the oesophagus are retracted medially. The prevertebral fascia and the longus colli muscle are visualised.

 

Pretracheal fascia

Trachea

Thyroid gland

Platysma

Carotid sheath

Deep cervical fascia

Sternocleidomastoid muscle

 

 

 

 

Deep dissection

Figure 3.2 Superficial dissection.

 

Structures at risk

• Vertebral artery

• Sympathetic nerve and stellate ganglion

• Spinal cord injury

 

 

The prevertebral fascia is incised with blunt dissection to expose the anterior surface of the cervical spine with the two longus colli muscles. The right and left longus colli muscles are stripped subperiosteally from the anterior vertebral bodies, using cautery good haemostasis (Figure 3.3). The smooth-ended retractor blades are placed underneath the

 

 

Larynx

 

Prevertebral fascia

 

Carotid sheath Longus colli

Intervertebral disc Vertebral artery

 

 

 

Figure 3.3 Deep dissection.

 

two longus colli muscles to improve the exposure; this helps to protect the oesophagus, recurrent laryngeal nerve, trachea and carotid sheath from injury by the retractors.

The appropriate level is identified using a bent needle as a marker (bent at about 1 cm to act as a stop) seen on a lateral radiograph using an image intensifier. After the level is identified, the further procedure of decompression, fusion or stabilisation is carried out.

 

Closure

After removal of the retractors, special attention is paid to haemostasis of all the layers, as a retractor could have acted as a temporary tamponade. Also, check for any injury to the visceral structures.

A deep drain is placed with care and kept for 24 hours. The platysma is approximated well by interrupted suture. The subcutaneous layer is closed by 2-0 Vicryl. Skin is closed by subcuticular stitches or skin clips. Check for bleeding at the Mayfield clamp pin site and apply Opsite spray or dressing as required.

 

Postoperative care and instructions

Prescription of neck collars varies according to the pathology, type of surgery/stabilisation and surgeon’s choice.

 

Posterior approach to the cervical spine (C2-C7)

Preoperative planning

Indications

• Posterior stabilisation/fusion

  • Trauma, degenerative subluxation, after decompression/fusion

     

• Posterior decompression of the spinal canal or foraminae stenosis

  • Presenting symptoms – myelopathy, radiculopathy, neurological deficits

  • Degenerative pathology – facet joint arthritis, osteophytes, ligamentum hypertrophy, instability

  • Trauma – instability, bony and disc encroachment

  • Others – congenital stenosis, ossification of posterior longitudinal ligament, tumour, etc.

  • Posterior decompression is preferred to anterior decompression in multilevel (more than two levels) degenerative stenosis if suitable

• Biopsy/excision/drainage of collection

  • Tumour

  • Infection

     

     

    Consent and risks

    • Haemorrhage: Usually caused by straying away from subperiosteal plane and entering intermuscular plane. Extension of the exposure lateral to facet risks bleeding from the segmental vessels and venous plexus. Cervical canal also has a rich epidural venous plexus which can bleed profusely.

    • Dural tear.

    • Cord or nerve root damage (rare): It is important to use bipolar cauterisation while controlling bleeding near the cord and nerve roots. Cord handling needs to be kept to a minimum and care taken not to plunge instruments into the interlaminar space. The laminae can be surprisingly thin and fragile.

    • Vertebral artery injury (rare): Vertebral artery is at risk when the exposure extends over

      the transverse process and in surgery involving C1 and C2. Injury bilaterally endangers the blood supply to the hindbrain.

    • General morbidity and mortality are shown to be increased in patients of older age and

    those with myelopathy.

     

     

    Operative planning

    An image intensifier should be available at the start of the procedure, for example to check for spine alignment during positioning in patients who have instability of the cervical spine. The image intensifier is also used perioperatively to identify level, check spinal alignment, and check implant, screw and graft position. For other considerations at this stage, see ‘Anterior approach to the cervical spine (C3-T1)’ earlier in this chapter.

     

    Anaesthesia and positioning

    The operation is performed under general anaesthesia. The patient is placed in the prone position on the operating table. The head end of the patient is positioned at the opposite side to the anaesthetist. The long anaesthetic tubing is secured safely.

     

    The head is positioned in a special head ring or brace, or held by a Mayfield skull clamp attachment, which provides three-point rigid cranial fixation, allows greater flexibility in positioning and better visualisation during imaging. The eyes should be protected appropriately during prone positioning. During exposure, the neck is positioned in slight flexion, to allow easier dissection and avoid skin creasing.

    The spinal stability needs to be taken into account and the spinal alignment checked with imaging if necessary. As with the anterior approach, broad strips (10 or 15 cm [4 or 6 inches]) of adhesive tape are used to pull the shoulders down, and the positions of the image intensifier and microscope are checked. The head end of the table is tilted upwards to minimise venous bleeding.

     

    Surgical technique

    Landmarks

    Identification of the level is important to avoid unnecessary dissection of the wrong levels. The external occipital protuberance and the longer spinous processes of C2, C7 and T1 vertebrae are easily palpable landmarks to guide the location of the incision. An image intensifier may be used to verify the level as needed.

     

    Incision

    A midline straight incision centring over the exposure is required. The skin in this area is vascular and thick and adrenaline can be injected to reduce bleeding.

     

    Superficial dissection

     

    Structures at risk

    Segmental vessels and venous plexi. (Bleeding is much worse if dissection strays from the midline or into muscle. Lateral extension of the dissection beyond the facet joint risks bleeding from the segmental vessels.)

     

     

    The fascia is incised at the midline. Retractors and palpation are used to keep dissection in the midline. The nuchal ligament is split in the midline, and the spinous process is reached. The spinous processes of C3, C4, C5 and C6 are normally bifid.

    Using Cobb elevators and diathermy, further dissection is carried out in the subperiosteal plane reflecting the paracervical muscles off the spinous process and the lamina, either bilaterally or unilaterally as required. The extent of lateral extension depends on the procedure planned, e.g. need to expose the facet joint or transverse process.

     

    Deep dissection

     

    Structures at risk

    • Dura

    • Cord and nerve root

    • Vertebral artery

    • Epidural venous plexus

     

     

    Care should be taken to avoid plunging instruments into the interlaminar space. If required, the ligamentum flavum is detached from the inferior lamina using a spatula, Kerrison punch or triple zero curette. Further laminotomy, laminectomy or laminoplasty are carried out as needed (Figure 3.4).

     

     

    Spinous process

    Fascia

    Trapezius

     

    Paracervical muscles

    Lamina

     

    Posterior tubercle

    Superior articular process

    Spinal nerve

    Vertebral artery

    Vertebral body

    Anterior tubercle

     

     

     

     

    Closure

    Figure 3.4 Deep dissection.

• Approximation of fascia with musculature and the nuchal ligament.

• Approximation of the subcutaneous tissue and the skin. The posterior neck skin is thick, and owing to skin creases, it is better to keep the neck in slight flexion if possible to attain better approximation, typically with subcutaneous sutures.

   

  Postoperative care and instructions

  Prescription of neck collars varies according to the pathology, type of surgery/stabilisation and surgeon’s choice.

   

  Posterior approach to the upper cervical spine (C1-C2)‌

  The approach is very similar to that of the lower cervical spine, and it is recommended that this section is read in conjunction with the previous one.

   

  Preoperative planning

  Indications

• Posterior stabilisation and fusion (C1-C2, occipitocervical):

  • Trauma

  • Degenerative subluxation

  • Following decompression from other causes

• Posterior decompression:

  • Spinal canal stenosis from various aetiologies, e.g. rheumatoid arthritis, trauma, degeneration, tumour

     

     

    Consent and risks

    • Similar to posterior approach of C2–C7.

    • Haemorrhage: The venous plexi are rich around the C2 nerve root and posterior to C1-C2 facet, and they tend to bleed profusely.

    • Vertebral artery injury: Vulnerable at C1 level, passing through the foramen transver-

      sarium of the C1 it turns medially and runs in the groove of C1 to pierce the posterior atlanto-occipital membrane and enter the foramen magnum.

    • Nerve injury: The greater occipital nerve (branch of posterior rami of C2), third occipital

    nerve (branch of posterior rami of C3) and suboccipital nerve are prone to injury if you stray away from the subperiosteal plane, while dissecting laterally.

     

     

    Operative planning

    This is similar to the posterior approach of C2-C7. Three-dimensional computed tomography (CT) reconstruction is needed to plan the appropriate angle for C1-C2 transarticular screw fixation.

     

    Anaesthesia and positioning

    See ‘Posterior approach to the cervical spine (C2-C7)’ earlier in this chapter.

     

    Surgical technique

    Landmarks

• External occipital protuberance in the posterior aspect of the skull in the midline (midpoint of the superior nuchal line)

• The spinous process of C2 vertebra (the longest in the upper cervical spine) An image intensifier can also be used to verify the level as needed.

  Superficial dissection

   

  Structures at risk

  • Suboccipital venous plexus

  • Vertebral artery

   

   

  See ‘Posterior approach to the cervical spine (C2-C7)’ earlier in this chapter. The Cobb elevator and diathermy are used to separate the musculature from the occiput (superior nuchal line to superior margin of foramen magnum). Subperiosteal dissection is carried out separating the muscles from the C1 and C2 spinous processes and lamina, taking care of the interlaminar spaces, venous plexus and vertebral artery.

   

  Deep dissection

  If required, the ligamentum flavum is detached between C1 and C2 and the posterior atlanto-occipital membrane between occiput and C1, using a triple zero curette, spatula or Kerrison punch.

   

  Postoperative care and instructions

  Prescription of neck collars varies according to the pathology, type of surgery/stabilisation and surgeon’s choice.

   

  Halo vest fixation of the cervical spine‌

  Preoperative planning

  Indications

• Cervical spine trauma (temporary or definite stabilisation), e.g. odontoid and upper cervical spine fracture, fracture of the occipital condyles

• External stabilisation following surgery as a primary stabiliser or as an adjuvant, e.g. after osteotomy for ankylosing spondylitis

• Instability due to infection or tumour

• Paediatric patients: Trauma, after fusion, scoliosis and other pathologies

• Halo traction (halo-gravity traction, halo-wheelchair traction, halo-pelvic traction): Trauma, scoliosis, after surgery, etc.

   

  Contraindications

• Active infection at the pin site area or in the area of the skin covered by the vest

• Patients with conditions where pin purchase in the skull bone is unlikely to provide adequate support for the required duration, e.g. rheumatoid arthritis

• Doubt about patient compliance, understanding and ability to cope,

  e.g. dementia

• Patients experiencing recurrent, significant falls

   

   

  Consent and risks

• Pin loosening: 36%–60% (The pin should be retightened regularly using 8 inch-pounds torque [2–5 inch-pounds torque for children].) It is retightened 48 hours after initial application and thereafter every week. If the resistance is not met after a few full turns, then a fresh pin is applied in a new adjacent location as appropriate. This complication can be minimised by selecting an appropriate pin insertion site on the skull, adopting a perpendicular pin insertion angle and using the correct pin insertion torque

• Pin site infection: 20%

• Pin migration and dural puncture

• Loss of reduction: More common in anterior column insufficiency/poor reduction/poorly fitted vest mainly in obese or very thin individuals

• Pressure sores and skin problems underlying the vest area

• Restricted ventilation and pneumonia

• Restricted arm elevation

• Scar

• Dysphagia: 2%. Can be prevented by avoiding immobilisation at extreme range of neck extension

• Palsy of the sixth cranial nerve with traction

   

  Operative planning

  Templating

  The patient’s head circumference and chest circumference are measured to determine the crown and vest size, respectively. The manufacturer of the halo vest provides a rough guidance with regard to selection of the sizes (paediatric, small, medium and large). The halo ring can be trialled to check that it provides a clearance all round the head circumference of 1–2 cm. Availability of the correct size of the crown and vest, and other equipment and materials, is confirmed.

  Three or more people are usually needed for the application of the vest and for logrolling the patient, if required. The nature and type of the neck instability should be taken into account by the surgeon. An image intensifier can be used, if needed, to assess cervical position. A crash trolley should be available for emergency resuscitation.

   

  Anaesthesia and positioning

  The operation is performed under local anaesthesia, enabling recognition of any changes in the neurological status during the procedure and manipulation. General anaesthesia is occasionally required if concomitant surgical procedures are carried out.

  A hard cervical spine collar is applied for provisional additional support, to improve stability and prevent neurological deterioration. The patient is positioned supine, with the head close to the edge or beyond the edge of the bed, so that the posterior portion of the ring can be positioned appropriately. Most modern systems have either the posterior position of the ring open or curved superiorly to enable easy positioning. If slight extension of the cervical spine is desired to improve alignment, then a saline bag is placed between the scapulae.

  The positioning of the image intensifier during the procedure needs to be planned. The accessibility of the image intensifier and the ability to visualise the required field must be checked.

   

  Surgical technique

  Selection of pin insertion sites

  Anterior pin sites

  Anterolateral aspect of the skull, about 1 cm superior to the supraorbital rim, above the lateral two-thirds of the eyebrows (Figure 3.5). This site is optimal (relatively safe zone) for the following reasons:

   

  Supratrochlear nerve

  Frontal sinus

  Supraorbital nerve

  Safe zone

   

   

   

  Figure 3.5 Safe zones for anterior and posterior pin placement.

   

• It is lateral to the frontal sinus, supratrochlear nerve and supraorbital nerve (structures at risk).

• It is medial to the temporalis muscle (pin penetration can lead to pain during mastication and speaking), temporalis fossa (thin bone) and zygomaticotemporal nerve.

   

• There is adequate skull thickness.

• It is below the equator (largest circumference) of the skull (prevent cephalad migration).

   

  Posterior pin sites

  Posterolateral aspect of the skull at the 4 o’clock and 8 o’clock positions, roughly diagonal to the contralateral anterior pins (Figure 3.5). These sites are

• Below the equator of the skull, but still 1 cm above the upper tip of the ear

• Where the skull is more uniformly thick

• Away from at-risk neurological and muscular structures

 

Halo application

Appropriate sterile precautions are undertaken during halo ring application using sterile pins and ring. Care is taken to avoid injury to the eye during the procedure.

The halo ring is positioned about 1 cm above the superior ear tip and eyebrows, but below the equator of the skull. It is temporarily stabilised using three positioning baseplates (Figure 3.6) at the 12 o’clock, 5 o’clock and 7 o’clock positions. The appropriate locations for the pin sites and the corresponding holes in the ring are identified. Hair is shaved or trimmed over the posterior pin sites, if required. The skin over the chosen pin site area is prepared with antiseptic solution and is infiltrated with local anaesthetic solution.

 

 

 

 

Figure 3.6 Pin sites and temporary positioning baseplates.

 

The pins are positioned in the corresponding holes and advanced through the skin as perpendicular as possible to the skull surface. (A perpendicular bone-pin interface enables increased contact area of the pin tip and so better purchase.) The patient should gently close the eyes and relax the forehead when the anterior pins are fixed. This avoids skin tethering and problems with eyelid closure. Direct insertion of pins into the skin

 

without a prior skin incision is preferred. A single-use torque-limiting device, which breaks off when a torque of 8 inch-pounds is reached, is available in some halo systems. These are used to advance the pins if available; if not a torque-limiting screwdriver is used.

The pins are tightened in diagonal fashion, by working on the contralateral pins concurrently (see Figure 3.6). Each pin is secured using a locknut to prevent loosening. The locknuts are tightened gently, as over-tightening can result in backing out of the pin. After the locknut comes in contact with the ring, it is tightened further by one-eighth turn with the spanner supplied. If skin tenting is noted around the pin, a skin release can be performed with a scalpel. Now the secured halo ring can be used to control and position the cervical spine for further procedures.

 

Vest application

The posterior and anterior halves of the vest are separated, but left connected to their respective two upright posts. The bolts, nuts and connectors are loosened but dismantling of various parts of the vest is best kept to a minimum, to avoid confusion and save time. After the neck is stabilised to the trunk manually, the trunk is lifted or logrolled for the placement of the posterior vest and the two upright posts.

The anterior vest is applied next. Both halves of the vest are connected and tightened to a level that will allow two fingers to slide between the vest and chest. The patient should be able to breathe comfortably. Both the shoulder straps are also fixed and tightened. The two right posts are connected loosely to the right connector and similarly the left two posts are connected to the left connector. Both the connectors are then slackly fixed to the halo ring. The head and neck are positioned and all the bolts and nuts are tightened after placing the posts and connectors in the appropriate position. Attach the spanner to the front of the anterior vest for quicker access, to deal with any emergency that requires vest removal.

An image intensifier may be used to check the cervical spine position and to enable correction under image guidance. All of the fixations are retightened when a satisfactory position is achieved.

 

Halo application in children

Multiple pins and low torque techniques are used. For older children, the torque used for pin application is 2–5 inch-pounds. Six pins or more can be used. For children under 3 years, 10–12 pins can be used. A CT scan of the skull helps to plan pin placements, by avoiding thin bone and suture lines. The pins are hand tightened only. Custom-made halo vest components may be required or a plaster jacket can be applied instead.

 

Postoperative care and instructions

If an image intensifier was not used, a radiograph is used to check the alignment.

Forty-eight hours after application the locking nuts are unlocked and all of the pins retightened to 8 inch-pounds. The locking nuts are retightened. The pins and other fixations must be rechecked regularly – at least every 2 weeks thereafter. Regular care is required

 

for the pin sites and the skin under the vest. Regularly check imaging as appropriate, as loss of reduction is common. One spanner should always be attached to the anterior vest and the rest of the application tools and spares to be kept by the patient.

 

Recommended references

Bauer R, Kerschbaumer F, Poisel S. Atlas of Spinal Operations. New York, NY: Thieme Medical, 1993. Clark CR. The Cervical Spine, 3rd ed. Philadelphia, PA: Lippincott Raven, 1998.

Fountas KN, Kapsalaki EZ, Nikolakakos LG et al. Anterior cervical discectomy and fusion associated complications. Spine (Phila Pa 1976). 2007;32(21):2310–2317.

Gokaslan ZL, Bydon M, De la Garza-Ramos R et al. Recurrent laryngeal nerve palsy after cervical spine surgery: A multicenter AO Spine Clinical Research Network Study. Global Spine J. 2017;7(1 Suppl): 53S–57S.

Nordin M, Frankel VH. Basic Biomechanics of the Musculoskeletal System, 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins, 2001.

 

Viva questions‌

1. How do you position a patient for anterior cervical spine surgery?

2. Describe the steps of the anterior cervical approach and the reasons behind them.

3. What are the structures at risk in anterior cervical surgery and how are they avoided?

4. Describe the radiological signs indicating cervical spine instability.

5. Describe how you will position a patient for the posterior approach to the cervical spine.

6. What are the structures at risk during a posterior approach to the lower cervical spine and how can they be avoided?

7. What are the structures at risk during a posterior approach to the upper cervical spine and how are they avoided?

8. How do you apply a halo to stabilise the cervical spine?

9. What complications occur in halo stabilisation of the cervical spine?

10. How is a halo vest looked after following application?