Posterior Cervical Laminectomy and Fusion

The operation. Posterior cervical laminectomy and fusion decomposes the cervical spinal cord posteriorly across multiple stenotic levels and immediately stabilises the decompressed segments with lateral mass screws, rods and a posterolateral fusion mass. It is the workhorse posterior operation for multilevel cervical myelopathy. Primary indication. Multilevel cervical myelopathy (three or more levels) with progressive neurological deficit, where the stenosis spans too many levels for a practical anterior construct and cervical lordosis is preserved (a C2-C7 Cobb angle of 20-40 degrees). Lordosis is essential — it lets the spinal cord drift posteriorly, away from anterior pathology, after the laminae are removed. Absolute indications:

• Multilevel cervical myelopathy (three or more levels) with a progressive neurological deficit
• Cervical stenosis with preserved cervical lordosis (20-40 degree C2-C7 Cobb angle)
• OPLL (ossification of the posterior longitudinal ligament) causing cord compression
• Congenital cervical stenosis (canal diameter less than 13mm) with symptomatic myelopathy Relative indications:
• Multilevel stenosis that has failed conservative management (more than 3-6 months)
• Multilevel spondylotic myelopathy with posterior-predominant compression
• Multilevel cervical radiculopathy not amenable to an anterior approach
• Combined central and foraminal stenosis across multiple levels Absolute contraindications:
• Cervical kyphosis — the cord cannot drift back off a kyphotic vertebral body column, so anterior column support is needed first (or a combined approach)
• Primarily anterior pathology (large disc herniation, anterior osteophytes) — ACDF is better
• Active cervical spine infection (pyogenic discitis, osteomyelitis)
• Medical instability precluding prolonged anaesthesia Relative contraindications:
• Severe osteoporosis (T-score less than -3.0) — screw purchase is compromised
• Previous posterior cervical surgery with heavy scarring
• Obesity with poor posterior neck anatomy exposure
• Single or two-level disease — ACDF is preferred for limited disease
• Loss of cervical lordosis below 10 degrees — consider a combined approach Clinical assessment — confirm myelopathy before operating. Myelopathy signs (upper motor neuron): Hoffman's sign (flick the distal phalanx of the middle finger to elicit thumb flexion), the inverted radial reflex (brachioradialis tap produces finger flexion — a C5-6 lesion), hyperreflexia in the lower extremities with clonus, Lhermitte's sign (neck flexion sends an electric shock down the spine), and a spastic, broad-based, circumducting gait. Radiculopathy signs (lower motor neuron): C5 — deltoid/biceps weakness, reduced biceps reflex; C6 — wrist extension weakness, reduced brachioradialis reflex; C7 — triceps weakness, reduced triceps reflex; C8 — finger flexion weakness, reduced grip. Modified JOA score (17 points): motor function upper extremity (0-5), motor function lower extremity (0-7), sensory upper extremity (0-2), sensory trunk and lower extremity (0-2), bladder function (0-1). A score below 12 indicates moderate-to-severe myelopathy warranting surgery. Why posterior, not anterior. For multilevel disease with preserved lordosis and posterior-predominant compression, a single posterior approach decompresses everything in one field while preserving motion at C2-3 and C6-7. The AOSpine North America CSM study (Fehlings) showed anterior and posterior approaches are equivalent once patient and disease factors are controlled — so the choice rests on alignment, number of levels and where the compression sits, not on presumed superiority. Consent. Discuss a C5 palsy (5-10 percent, usually recovering 80-90 percent by a year), dural tear (5-8 percent), spinal cord injury (0.2-0.4 percent, devastating), vertebral artery injury (less than 0.5 percent, stroke risk), wound infection (1-3 percent) and an epidural haematoma (1-2 percent, a surgical emergency). Mean blood loss is 300-500mL.

The goal is to expose the posterior cervical spine through a single midline incision, confirm the levels, insert lateral mass screws for immediate stability, remove the laminae and ligamentum flavum to decompress the cord, restore the facet-bound foraminal width, contour rods to preserve lordosis, lay down a posterolateral fusion mass, achieve meticulous haemostasis and close in layers over a drain. The exposure is the foundation — it is laid out step by step in the timeline below.

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Key operative anatomy. The lateral mass is the bony block between the superior and inferior articular processes, unique to C3-C7 — roughly 10-15mm high, 8-12mm wide and 6-10mm deep (C3 is smallest and may need a 3.0mm screw; C7 is largest but carries an anterior vertebral artery course). Three structures surround it and dictate screw trajectory: the nerve root lies medial, the vertebral artery lies just 1.5-2mm lateral to the lateral mass edge in the foramen transversarium, and the carotid sheath and oesophagus lie anterior. Cervical roots exit ABOVE their pedicle (C5 exits at C4-5, the opposite of the lumbar spine), and the C5 root is shortest (25-30mm), most horizontal and least mobile — which is why it is the root most often palsied. The ligamentum flavum is normally 3-5mm of thick yellow elastic tissue (hypertrophying to 7-10mm in stenosis), with the dura immediately anterior to it (0-2mm gap).

Immediate post-operative (0-24h). Hourly neurological checks (motor and sensory, all extremities). Watch for the C5 palsy (delayed deltoid/biceps weakness at 24-48h) and an epidural haematoma (acute neurological deterioration = emergency MRI). Elevate the head of the bed 30-45 degrees to reduce swelling; monitor drain output (remove below 50mL/24h, typically 24-48h). Multimodal analgesia: paracetamol, NSAIDs, opioids as needed. Early mobilisation (1-7 days). Mobilise on day 1 with physiotherapy — no collar is needed with an instrumented fusion. Log-roll for comfort in the first 48h. Deep breathing and incentive spirometry prevent atelectasis. VTE prophylaxis: sequential compression devices, early mobilisation, and chemical prophylaxis (enoxaparin 40mg daily) if bleeding risk is low. Day-1 AP and lateral radiographs confirm alignment and hardware. Discharge and rehabilitation (2-5 days typical). Discharge when the patient mobilises independently, pain is controlled on oral medication, there is no neurological deterioration, the drain is out and the wound is dry. BLT precautions (bending, lifting more than 5kg, twisting) for 6 weeks. Keep the wound dry for 10 days; remove sutures/staples at 10-14 days. Red flags: fever above 38.5 degrees Celsius, wound drainage, neurological change, severe pain. Follow-up at 2 weeks (wound check), 6 weeks, 3 months, 6 months and 1 year. Rehabilitation protocol:

• Weeks 0-6: BLT precautions; gentle active range-of-motion exercises, no resistance
• Weeks 6-12: progressive strengthening, isometric cervical exercises
• Month 3 onward: full activity as tolerated if fusion is progressing on imaging
• Return to work: sedentary at 4-6 weeks, manual labour at 3-6 months (after fusion is confirmed)
• Driving: when comfortable turning the head, off opioids — typically 2-4 weeks Imaging follow-up and fusion assessment:
• Day 1: AP and lateral radiographs (baseline alignment, hardware)
• 6 weeks: cervical radiographs (alignment, hardware, early fusion)
• 3 months: CT cervical spine (bridging bone across the fusion mass)
• 6 months: flexion-extension radiographs (dynamic stability)
• Radiographic fusion = bridging bone across the levels on CT; dynamic fusion = less than 2mm translation or less than 5 degrees angulation on flexion-extension. Time to fusion is 3-6 months in the cervical spine (faster than lumbar); pseudarthrosis is defined as no bridging bone at 12 months on CT.

Complication rates at a glance. Neurological: C5 palsy 5-10 percent (usually recovers 80-90 percent); spinal cord injury 0.2-0.4 percent (devastating, permanent); nerve root injury 2-5 percent (from screw malposition). Haemorrhagic: epidural haematoma 1-2 percent (surgical emergency); vertebral artery injury less than 0.5 percent (stroke risk); mean blood loss 300-500mL. Mechanical: screw malposition 2-5 percent; post-laminectomy kyphosis 10-20 percent without fusion, less than 2 percent with fusion; pseudarthrosis 5-10 percent (higher in smokers); hardware failure 1-3 percent. Infectious: wound infection 1-3 percent; discitis/osteomyelitis less than 1 percent (delayed, weeks post-op); meningitis less than 0.5 percent (if dural tear). Other: dural tear 5-8 percent (higher in revision and OPLL); dysphagia rare with a posterior approach (less than 1 percent); adjacent segment disease 2-3 percent per year; axial neck pain 15-20 percent (myofascial).

Why lordosis matters. The cervical cord sits towards the posterior canal only when the spine is lordotic. Laminectomy removes the posterior tension band and therefore has a kyphotic tendency — in a kyphotic spine the cord drapes over the vertebral bodies and remains compressed, which is why a preserved lordosis (20-40 degree C2-C7 Cobb angle) is the single most important indication criterion, and why instrumented fusion to maintain that lordosis is mandatory. Canal dimensions. The normal cervical canal measures 14-18mm sagittally; stenosis is defined as an absolute diameter below 13mm or a Pavlov ratio below 0.8. The cord is approximately 10mm, so the "space available for the cord" is the canal diameter minus the cord diameter. The surgical target after decompression is a canal diameter greater than 13mm. Post-laminectomy kyphosis. Without fusion, kyphosis develops in 10-20 percent of adults (and up to 50 percent of children); with instrumented fusion it falls below 2 percent. Risk factors: a multilevel laminectomy (more than 3 levels), young age (less than 25 years) and pre-existing loss of lordosis. This is the biomechanical justification for routine fusion. Lateral mass screw biomechanics. Pullout strength is 400-800N depending on bone density and trajectory. Optimal screw length is 12-14mm unicortical (16-18mm if bicortical, though bicortical is not required and risks anterior breach). Bilateral triangulation gives coronal stability; the rod-screw construct provides immediate rigid fixation, and compression across the levels loads the posterolateral graft. Key evidence. The AOSpine North America CSM study (Fehlings, 2013) showed anterior and posterior approaches are equivalent for cervical spondylotic myelopathy once patient and disease factors are controlled — the approach is chosen on alignment, level count and compression location. Heller (2001) found laminoplasty and laminectomy-with-fusion gave comparable decompression, but the laminectomy-fusion group carried more mechanical complications, underlining the need for solid instrumentation. Sakaura (2003) pooled the literature on the postoperative C5 palsy (mean 4.6 percent across techniques), establishing it as multifactorial and usually recovering. Yoshihara (2013) confirmed lateral mass screws have a very low neurovascular complication rate, and Anderson (1991) defined the original lateral mass fixation series with solid fusion and no neurovascular complications.