Anterior Cervical Corpectomy and Fusion

Surgical Indications

Absolute Indications

• Multilevel retrovertebral cord compression from large central disc-osteophyte complexes that cannot be addressed by discectomy alone
• Ossification of the posterior longitudinal ligament (OPLL) spanning one or more vertebral bodies with myelopathy
• Cervical burst fracture with retropulsed posterior wall fragment causing cord compression
• Primary or metastatic tumour involving the vertebral body with neurological deficit or instability
• Pyogenic or tuberculous spondylodiscitis with vertebral body destruction and abscess causing cord compression

Relative Indications

• Progressive cervical myelopathy with imaging evidence of retrovertebral pathology
• Failed anterior cervical discectomy and fusion at an adjacent level with new retrovertebral compression
• Kyphotic deformity secondary to vertebral body collapse requiring anterior column reconstruction

Contraindications

Absolute:

• Active systemic infection unrelated to the spine
• Severe untreated medical comorbidities precluding anterior cervical surgery
• Inability to tolerate prone positioning for supplemental posterior surgery when required

Relative:

• Previous anterior cervical surgery with extensive scarring (consider posterior approach or staged procedure)
• Isolated radiculopathy without myelopathy (ACDF usually sufficient)
• Poor bone quality precluding reliable screw fixation (consider posterior-only approach)

Evidence for Anterior Corpectomy

When Discectomy Is Insufficient

• Retrovertebral pathology (central osteophytes, OPLL, burst fragments) lies behind the vertebral body and cannot be reached through disc spaces alone
• Attempting to remove such pathology through a discectomy risks incomplete decompression and persistent myelopathy
• Corpectomy provides direct visualisation of the entire posterior longitudinal ligament across the affected levels

Reconstruction Options and Outcomes

• Structural autograft (fibula or iliac crest) remains the gold standard with fusion rates greater than 90 percent in single-level corpectomy
• Expandable cages with osteoinductive packing achieve comparable fusion rates with shorter operative time and no donor-site morbidity
• Anterior plating alone is sufficient for one- or two-level corpectomy; three or more levels have higher failure rates without posterior supplementation

Multilevel Constructs

• Two-level corpectomy with anterior plating alone has a 5-10 percent failure rate; adding posterior instrumentation reduces failure to less than 2 percent
• Three-level corpectomy without posterior support has failure rates exceeding 20 percent in some series; 360-degree stabilisation is strongly recommended

Relevant Cervical Anatomy for Corpectomy

The Smith-Robinson Plane

The approach utilises the natural plane between the carotid sheath laterally and the visceral structures (trachea, oesophagus, thyroid) medially. This plane is relatively avascular and allows safe access to the anterior cervical spine from C3 to T1.

Recurrent Laryngeal Nerve

• Right side: loops around the subclavian artery and ascends obliquely, crossing the field at approximately C5-C6
• Left side: loops around the aortic arch and ascends more vertically in the tracheoesophageal groove
• Below C6 the left-sided approach is often preferred because the nerve is more protected
• The nerve must be identified and protected during medial retraction of the trachea and oesophagus

Vertebral Artery

• Ascends through the transverse foramina from C6 to C1
• Lies 1.5-2 cm lateral to the uncovertebral joint line
• Vulnerable during lateral osteophyte resection or if the lateral border of the posterior longitudinal ligament is breached
• Never extend decompression beyond the lateral edge of the posterior longitudinal ligament

Posterior Longitudinal Ligament and Dura

• The posterior longitudinal ligament is the final soft-tissue layer before the dura
• In OPLL the ligament is ossified and may be densely adherent to dura
• In burst fractures the posterior wall fragments may have lacerated the dura
• Always confirm the plane between ligament and dura before division; have dural repair materials available

Endplate Anatomy

• The superior and inferior endplates are covered by a thin layer of hyaline cartilage that must be completely removed
• The bony endplate must be preserved to support the strut graft or cage
• Over-aggressive endplate removal weakens the vertebral body and increases subsidence risk

Positioning and Preparation

Patient position: Supine on a radiolucent table with the head in neutral or slight extension on a Mayfield headrest or foam pad. The shoulders are taped down to improve fluoroscopic visualisation of the lower cervical spine. Slight reverse Trendelenburg reduces venous bleeding.

Anaesthesia: General endotracheal anaesthesia with neuromonitoring (somatosensory and motor evoked potentials). The endotracheal tube is taped to the contralateral side. A nasogastric tube may be placed to help identify the oesophagus.

Approach side: Left-sided for levels below C6 because of the more protected recurrent laryngeal nerve course. Right-sided approach is acceptable for C3-C5 or when the surgeon is right-handed.

Equipment: High-speed burr, Kerrison rongeurs, pituitary rongeurs, curettes, vertebral body spreaders, structural graft or expandable cage, anterior cervical plate and screws, fluoroscopy or navigation.

Step-by-Step Operative Technique

Step 1: Incision and Exposure

A transverse skin incision is made at the level of the corpectomy, centred on the anterior border of the sternocleidomastoid. The platysma is divided transversely. The anterior border of the sternocleidomastoid is identified and the plane between it and the strap muscles is developed. The carotid sheath is retracted laterally and the trachea/oesophagus medially. The prevertebral fascia is divided in the midline and the longus colli muscles are elevated from the vertebral bodies.

Step 2: Disc Removal Above and Below

The discs above and below the corpectomy level are removed completely using pituitary rongeurs and curettes. This defines the cephalad and caudad limits of the corpectomy and creates working space. The posterior longitudinal ligament is exposed at the disc levels but not yet divided.

Step 3: Central Corpectomy

A high-speed burr is used to create a central trough through the vertebral body, removing cancellous bone until the posterior cortical wall is reached. The trough is kept midline and widened to the lateral extent of the posterior longitudinal ligament. The uncovertebral joints are used as the safe lateral landmark — they are never breached.

Step 4: Posterior Wall and Ligament Removal

Once the posterior cortical wall is thinned, it is removed with Kerrison rongeurs from the centre laterally. The posterior longitudinal ligament is then divided or resected under direct vision. In OPLL the ossified ligament may be adherent to dura; careful separation with a fine instrument is required. Any dural tear is repaired primarily or with a patch.

Step 5: Endplate Preparation

The superior and inferior endplates are prepared by removing all remaining cartilage with curettes until punctate bleeding is seen. The bony endplate is preserved. The endplates are made parallel and any osteophytes are removed to create a flat surface for the strut or cage.

Step 6: Reconstruction

The corpectomy defect is measured. A structural strut (fibula autograft, iliac crest autograft, or allograft) or expandable cage is selected. The graft or cage is sized 1-2 mm longer than the measured defect to achieve slight distraction. The graft is impacted into place or the cage is expanded under fluoroscopic control. An anterior cervical plate is applied, engaging the vertebrae above and below with bicortical screws where possible.

Step 7: Closure and Multilevel Considerations

The wound is closed in layers over a drain. For two-level corpectomy, anterior plating alone may suffice if bone quality is good. For three or more levels, or in patients with poor bone quality or kyphosis, supplemental posterior instrumentation is strongly recommended.

Post-operative Protocol

Immediate Post-operative (Day 0-2)

• Neurological monitoring in recovery and high-dependency unit for 24 hours
• Drain removed at 24-48 hours if output is low
• Cervical collar for comfort (soft collar for 2-4 weeks in most cases)
• Early mobilisation with physiotherapy supervision
• Swallow assessment before oral intake if extensive retraction was required

Early Phase (Week 2-6)

• Gradual weaning of collar as pain and swelling subside
• Active range-of-motion exercises for neck within comfort limits
• Progressive strengthening of upper limbs
• Smoking cessation support if applicable
• Serial radiographs at 2 and 6 weeks to assess graft position

Late Phase (Month 3-12)

• Dynamic radiographs or CT at 3 and 6 months to assess fusion
• Return to light work at 6-12 weeks; heavy manual work at 4-6 months
• Full fusion expected by 6-12 months
• Persistent dysphagia beyond 3 months warrants swallow study and ENT review

Special Considerations for Multilevel Constructs

• Two-level corpectomy: anterior plating alone is often sufficient if bone quality is good and patient is non-smoker
• Three or more levels: posterior instrumentation (lateral mass screws or pedicle screws) is strongly recommended to reduce failure rate from greater than 20 percent to less than 5 percent
• Poor bone quality (osteoporosis, rheumatoid): consider circumferential fusion regardless of number of levels
• Post-operative bracing: rigid collar or halo for 6-12 weeks in high-risk constructs