Decision Framework

• Key principle: approach from the direction of the compressive pathology
• Anterior compression (disc herniation, osteophyte, vertebral body pathology) → anterior approach
• Posterior compression (ligamentum flavum hypertrophy, facet overgrowth, multilevel stenosis) → posterior approach
• Circumferential compression: may require combined or staged approach
• Other factors: number of levels, sagittal alignment (lordosis vs. kyphosis), prior surgery, medical comorbidities

Cervical Spine Approaches

Lumbar Spine Approaches

ACDF Complications

• Recurrent laryngeal nerve injury: hoarseness; historically taught to be more common with right-sided approach due to RLN course variability, but current evidence shows no significant difference between sides. Surgeon preference and prior neck surgery typically dictate side. Transient in most cases.
• Dysphagia: most common complication — early postoperative dysphagia up to 50% (most resolves over weeks to months); persistent dysphagia at 1 year ~5–15%
• Esophageal perforation: rare but serious
• Vertebral artery injury: rare; risk with far-lateral dissection
• Adjacent segment disease: long-term degeneration above/below the fusion

When to Fuse

When NOT to Fuse

• Simple lumbar disc herniation: discectomy/microdiscectomy alone is sufficient
• Single-level lumbar laminectomy: no evidence of benefit from adding fusion if spine is stable
• No instability on flexion/extension imaging
• Laminoplasty: inherently motion-preserving; does not require fusion

Instrumentation

• Pedicle screws: strongest posterior fixation point; placed through vertebral pedicle into body; used with rods for posterior stabilization
• Lateral mass screws: used in subaxial cervical spine (C3–C7) where pedicles are too small for pedicle screws; C7 lateral mass is thinner than C3–C6, so pedicle screws are sometimes preferred at C7 for stronger fixation
• Interbody cages: structural spacer placed in disc space; filled with bone graft; restores disc height and provides anterior column support
• Bone graft options: autograft (iliac crest — gold standard), allograft, BMP-2 (bone morphogenetic protein); BMP-2 has complications including heterotopic ossification and swelling

Adjacent Segment Disease (ASD)

• Accelerated degeneration of levels adjacent to a fusion due to increased biomechanical stress
• Radiographic changes in up to 25–30% at 10 years; symptomatic ASD in ~10%
• More common with longer fusion constructs and multilevel fusions
• Motion preservation (disc arthroplasty, laminoplasty) may reduce ASD risk — theoretical benefit, long-term data still accumulating

Clinical Presentation

• Classic triad: bilateral lower extremity weakness/pain, saddle anesthesia (S2–S5), bladder dysfunction
• Red flags requiring urgent imaging:
  • Bilateral sciatica (especially new onset)
  • Saddle anesthesia or perineal numbness
  • Urinary retention (most consistent finding) with overflow incontinence
  • Decreased rectal tone / fecal incontinence
  • Progressive bilateral leg weakness
  • Sexual dysfunction (new onset)
• Most common cause: large central lumbar disc herniation (most often L4–L5 or L5–S1)
• Other causes: spinal epidural abscess, epidural hematoma, tumor, spinal stenosis, post-surgical

Incomplete vs. Complete CES

Diagnosis

• MRI is the study of choice — demonstrates level and cause of compression
• CT myelogram if MRI contraindicated
• Post-void residual >200 mL supports diagnosis in equivocal cases
• Do NOT delay imaging for urodynamics or EMG

Surgical Timing

• Surgical emergency: decompression ideally within 24 hours of symptom onset
• Earlier surgery (<24 hours) associated with better neurological and bladder outcomes in most studies
• Surgery within 24–48 hours is still beneficial; outcomes decline significantly after 48 hours
• CES-I → CES-R conversion can occur rapidly — argue for earliest possible decompression to prevent progression
• Standard procedure: wide laminectomy with discectomy at the affected level

Definition & Pathophysiology

• Cervical spondylotic myelopathy (CSM): most common cause of spinal cord dysfunction in adults >55 years
• Chronic compression of the cervical spinal cord from degenerative changes: disc herniation, osteophyte formation, ligamentum flavum hypertrophy, OPLL
• Cord compression → demyelination → axonal loss → gliosis; often irreversible once established
• Cord signal change on T2 MRI indicates myelomalacia/gliosis; T1 hypointensity = worse prognosis

Clinical Features

• Gait dysfunction (broad-based, spastic); often the earliest motor finding
• Hand clumsiness / loss of fine motor dexterity (myelopathy hand — grip-and-release test; finger escape sign)
• Upper motor neuron signs: hyperreflexia, Hoffman sign, clonus, Babinski, spastic tone
• Lhermitte sign (electric shock sensation with neck flexion)
• Sensory changes: numbness, paresthesias in hands; posterior column dysfunction
• Bowel/bladder dysfunction: late finding indicating severe myelopathy

Modified Japanese Orthopaedic Association (mJOA) Score

Surgical Approach Selection

Key Considerations

• Natural history: CSM is generally progressive; stepwise deterioration is the most common pattern; rarely improves spontaneously
• Earlier surgery = better outcomes: patients with shorter symptom duration and less cord damage have better surgical results
• Collar immobilization does not treat myelopathy; used only for temporary stabilization in trauma or post-operatively

Epidemiology & Presentation

• Metastatic epidural spinal cord compression (MESCC) occurs in 5–10% of cancer patients
• Most common primary tumors: lung, breast, prostate, renal cell, multiple myeloma
• Thoracic spine is the most common location (~60%), followed by lumbar and cervical
• Back pain is the earliest and most common symptom (>90%); precedes neurologic deficits by weeks to months
• Progressive weakness, sensory level, bowel/bladder dysfunction indicate cord compression

NOMS Decision Framework

SINS (Spinal Instability Neoplastic Score)

• SINS 0–6: stable — no surgical stabilization needed
• SINS 7–12: potentially unstable — surgical consultation
• SINS 13–18: unstable — surgical stabilization indicated

The Patchell Trial (2005)

• Design: RCT comparing direct decompressive surgery + postoperative RT vs. RT alone for single-level MESCC
• Key finding: surgery + RT group had significantly more patients who regained/retained ability to walk (84% vs. 57%)
• Surgery group also had: longer ambulatory duration, longer survival, reduced need for opioids and corticosteroids
• Inclusion: single area of cord compression, at least one neurologic sign
• Exclusion: radiosensitive tumors (lymphoma, myeloma, leukemia, germ cell), multiple areas of cord compression; excluded patients who had been completely paraplegic for >48 hours prior to enrollment (these patients were not expected to recover function)
• Conclusion: surgery + RT is standard of care for single-level MESCC from radioresistant tumors in surgical candidates

Management Summary

Steroids in Metastatic Cord Compression

• Dexamethasone started immediately upon diagnosis — higher-dose regimens (96 mg load) have been used historically; current practice favors moderate dosing (10–16 mg load, 16 mg/day) due to side-effect profile
• Reduces vasogenic edema, provides temporary neurologic improvement
• Bridge to definitive treatment (surgery or radiation)

Lumbar Disc Herniation

• Natural history: most improve with conservative treatment over 6–12 weeks; disc resorption occurs in up to 60–70% over time
• Surgical indications:
  • Refractory radiculopathy after ≥6 weeks of conservative management
  • Progressive motor deficit (e.g., foot drop)
  • Cauda equina syndrome (emergency)
  • Intractable pain significantly impairing function
• SPORT trial (Spine Patient Outcomes Research Trial):
  • Surgery provides faster pain relief and functional improvement at 3 months and 1 year
  • By 4–8 years, outcomes tend to converge between surgical and non-operative groups (intent-to-treat analysis)
  • High crossover rate (~40% non-operative crossed to surgery) complicated interpretation
  • As-treated analysis favored surgery at all time points

Surgical Techniques for Disc Herniation

• Recurrence rate: 5–15% after microdiscectomy; recurrent herniation at same level may eventually require fusion

Lumbar Spinal Stenosis

• Neurogenic claudication: bilateral leg pain/heaviness/numbness worsened by walking and standing, relieved by sitting or leaning forward (flexion opens the canal)
• Differentiate from vascular claudication: neurogenic relieved by sitting/flexion; vascular relieved by standing still (no need to sit)
• Conservative treatment: PT, epidural steroid injections, activity modification; reasonable for mild-moderate symptoms
• Surgical indication: neurogenic claudication refractory to ≥3 months conservative treatment with significant functional limitation
• SPORT trial for stenosis: surgery (decompressive laminectomy) associated with greater improvement in pain and function compared to non-operative care at all time points up to 8 years
• Procedure: lumbar laminectomy (decompression) at affected levels; fusion added only if concurrent instability or spondylolisthesis

Spondylolisthesis

• Definition: anterior slippage of one vertebral body on another
• Wiltse classification (full list):
  • Type I — Dysplastic: congenital abnormality of the L5–S1 facets/pars; risk of high-grade slip
  • Type II — Isthmic: pars interarticularis defect (spondylolysis); most common at L5–S1; typical in young athletes (gymnasts, football linemen)
  • Type III — Degenerative: facet joint arthropathy; most common at L4–L5; more common in women >50
  • Type IV — Traumatic: acute fracture of a posterior element (other than pars) producing slip
  • Type V — Pathologic: tumor, infection, or metabolic bone disease weakening the posterior elements
  • Type VI — Iatrogenic: post-surgical (e.g., after wide decompression or facetectomy)
• Meyerding classification: Grade I (<25% slip), Grade II (25–50%), Grade III (50–75%), Grade IV (75–100%), Grade V (spondyloptosis = complete slip)

Surgical Management by Grade

Spine Surgery Urgency

Initial Management

• ATLS principles: airway (with in-line cervical stabilization), breathing, circulation; cervical collar + full spine precautions until cleared
• Assess level and completeness of injury; document baseline ASIA exam early and serially
• Avoid hypotension (MAP goal often 85–90 mmHg × 5–7 days in many protocols) to preserve cord perfusion

ASIA Impairment Scale (AIS)

Steroids in Acute Traumatic SCI

• Methylprednisolone is NOT recommended in acute traumatic SCI per AANS/CNS 2013 guidelines
• NASCIS I–III trials initially suggested benefit, but post-hoc subgroup analyses were methodologically flawed; subsequent reviews found no clear benefit and a harm signal (infection, GI bleeding, hyperglycemia, pneumonia)
• NASCIS controversy is considered resolved against routine steroid use

Timing of Decompression

• STASCIS trial (Fehlings 2012): prospective cohort of acute cervical SCI — decompression within 24 hours associated with significantly improved neurologic outcomes (≥2-grade AIS improvement at 6 months) compared to delayed surgery
• Earlier decompression is generally favored when patient is stable enough for surgery

Atlantoaxial Instability — High-Risk Populations

• Down syndrome: ligamentous laxity at C1–C2; screen with flexion/extension lateral C-spine films before contact sports or elective intubation. Symptomatic instability requires surgical fusion.
• Rheumatoid arthritis: chronic synovitis erodes the transverse ligament → C1–C2 subluxation, retro-odontoid inflammatory pannus (T1 iso, T2 bright, enhances), basilar invagination with cervicomedullary compression. Pre-operative cervical MRI mandatory before general anesthesia in long-standing RA.
• Klippel-Feil, Morquio syndrome (MPS IV), os odontoideum, achondroplasia — other congenital causes of upper cervical instability.

NEXUS Criteria

• The cervical spine can be clinically cleared without imaging if ALL of the following are present:
  1. No posterior midline cervical tenderness
  2. No focal neurologic deficit
  3. Normal level of alertness
  4. No evidence of intoxication
  5. No painful distracting injury
• High sensitivity for clinically significant cervical injury

Canadian C-Spine Rule

• Step 1 — High-risk factors requiring imaging: age ≥65, dangerous mechanism (e.g., fall from >3 ft / 5 stairs, axial load, high-speed MVC, motorized recreational vehicle, bicycle collision), or paresthesias in extremities
• Step 2 — Low-risk factors that allow safe assessment of range of motion: simple rear-end MVC, sitting in ED, ambulatory at any time, delayed onset of neck pain, no midline cervical tenderness
• Step 3 — Active rotation: if able to actively rotate the neck 45° bilaterally, no imaging required
• More specific than NEXUS in many studies; reduces imaging utilization in low-risk patients

Anatomic Classification

• Extradural: majority are metastatic (covered in MESCC section)
• Intradural-extramedullary (IDEM)
• Intramedullary (IM)

Intradural-Extramedullary (IDEM) Tumors

Intramedullary (IM) Tumors

Spinal Dural Arteriovenous Fistula (sDAVF)

• Most common spinal vascular malformation; abnormal connection between a radicular artery and a radicular vein within the dural sleeve of a nerve root
• Demographics: elderly men predominantly
• Location: low thoracic / thoracolumbar most common
• Clinical: progressive myelopathy (gait dysfunction, weakness, bowel/bladder), often misdiagnosed initially; Foix-Alajouanine syndrome = subacute necrotizing myelopathy from chronic venous congestion
• MRI: central T2 cord hyperintensity (cord edema from venous hypertension) + serpentine flow voids on cord surface
• Diagnosis: spinal angiography to identify the fistula site
• Treatment: endovascular embolization or surgical clipping of the fistula; both can be definitive

Spinal AVM (Intramedullary)

• True nidus within the cord parenchyma; congenital lesion; typically presents in younger patients
• Can present with hemorrhage (subarachnoid or intramedullary) or progressive myelopathy
• Treatment is multimodal: embolization, microsurgery, and/or radiosurgery depending on anatomy

• Definition: fluid-filled cavity (syrinx) within the spinal cord
• Causes:
  • Chiari I malformation (most common cause overall) — tonsillar descent obstructs CSF flow at the foramen magnum
  • Post-traumatic (often years after SCI)
  • Post-infectious (arachnoiditis)
  • Tumor-associated (intramedullary tumor with cyst)
  • Idiopathic
• Clinical: classic “cape” (suspended) distribution of pain/temperature loss over shoulders/upper arms with preservation of light touch (dissociated sensory loss); motor preservation early; later wasting of intrinsic hand muscles, scoliosis (especially in children)
• Diagnosis: MRI demonstrates the syrinx and the underlying cause
• Treatment: address the underlying cause — suboccipital decompression for Chiari-associated syrinx; syringo-subarachnoid or syringo-pleural shunt if syrinx persists or in selected refractory cases

• Tethered cord syndrome: abnormal caudal fixation of the spinal cord, producing traction-related neurologic dysfunction
• Anatomic causes:
  • Tight/thickened filum terminale
  • Conus below the L2 level in adults (normally ends ~L1–L2)
  • Intradural lipoma (lipomyelomeningocele)
  • Dermal sinus tract
  • Diastematomyelia (split cord)
  • Post-surgical scarring (re-tethering after myelomeningocele repair)
• Spina bifida spectrum:
  • Spina bifida occulta: bony defect only; often incidental; cutaneous markers (hair tuft, dimple, hemangioma) over the spine raise concern
  • Meningocele: herniation of meninges without neural tissue
  • Myelomeningocele: herniation of meninges + neural tissue; associated with Chiari II; closed within first 24–72 hours after birth (or prenatally per MOMS trial in selected cases)
• Clinical: progressive lower extremity weakness/sensory loss, bowel/bladder dysfunction, back/leg pain, foot deformity, scoliosis
• Treatment: surgical detethering — release of the filum and/or untethering of adherent structures

Background

• Most common in osteoporotic patients (postmenopausal women, chronic steroid use); also pathologic (metastasis, myeloma) and traumatic
• Acute fracture → midline back pain, often mechanical; can produce kyphotic deformity if multiple/severe
• Initial management: analgesia, bracing, treat underlying osteoporosis (bisphosphonates, denosumab, teriparatide); most heal conservatively over 6–8 weeks

Vertebral Augmentation Procedures

Evidence & Considerations

• Pain-relief evidence is mixed: early sham-controlled RCTs (Kallmes/Buchbinder 2009 NEJM) showed no benefit over sham; later trials (VAPOUR, VERTOS IV) suggest benefit in select patients with acute fractures and severe pain
• Most appropriate in patients with severe, refractory pain at a recent (<6–8 weeks) fracture and clear correlation between fracture level and symptoms
• Complications: cement extravasation (epidural, paravertebral, venous — pulmonary cement embolism), adjacent-level fractures (cement-stiffened segment increases load on adjacent vertebrae), infection, neurologic injury