What is the best course of treatment for an adult patient with a history of extensive spinal fusions, presenting with increased weakness and difficulty ambulating without assistance?

Evaluation and Management of Post-Fusion Weakness and Ambulatory Decline

Immediate Diagnostic Priorities

This patient requires urgent MRI of the entire spine to rule out acute spinal cord compression, adjacent segment disease, or hardware-related complications. Progressive weakness and ambulatory decline in a patient with extensive prior fusions represents a neurological emergency until proven otherwise 1, 2.

Critical Differential Diagnoses to Exclude

• Adjacent segment disease is the most common cause of new neurological symptoms after spinal fusion, characterized by degenerative changes at levels immediately above or below the fusion construct with new radiculopathy, myelopathy, or instability 2
• Spinal cord compression from epidural hematoma, infection, or mass lesion must be excluded urgently, as patients with progressive weakness require immediate imaging and potential surgical intervention 1, 3
• Proximal junctional failure (PJF) occurs when excessive biomechanical stress concentrates at the uppermost instrumented vertebra, particularly in patients with long fusion constructs, leading to fracture or kyphotic deformity 4
• Hardware failure or pseudarthrosis can cause instability and progressive neurological compromise, requiring revision surgery 2

Physical Examination Findings That Guide Management

• Document motor strength in all extremities using the 0-5 scale, with particular attention to lower extremity strength patterns that suggest specific nerve root or cord involvement 5
• Assess for myelopathic signs including hyperreflexia, clonus, Babinski sign, and gait instability, which indicate spinal cord compression requiring urgent decompression 1, 5
• Evaluate hip joint range of motion and function, as severe hip pathology can cause compensatory spine movement that becomes disrupted after fusion, leading to unexpected ambulatory decline 4
• Test for Lhermitte sign (electric shock sensation with neck flexion), which indicates spinal cord irritation and may suggest compression at the proximal junction 5
• Assess bladder and bowel function, as new urinary retention or incontinence represents cauda equina syndrome requiring emergency surgical decompression 6

Imaging Protocol

• Obtain MRI of the entire spine (cervical through lumbar) to evaluate for compression at any level, as symptoms may arise from segments distant from the original fusion 1, 5, 3
• Order standing flexion-extension radiographs of the spine to assess for instability at adjacent segments or within the fusion construct 2, 4
• Evaluate sagittal and coronal alignment on full-length standing spine radiographs, as malalignment contributes to adjacent segment degeneration and PJF 2, 4

Treatment Algorithm Based on Findings

If Acute Spinal Cord Compression is Identified

Urgent surgical decompression is mandatory within 24-48 hours to prevent permanent neurological injury. 1

• Patients with progressive myelopathy or cauda equina syndrome require emergency decompression regardless of other factors 1, 6
• The surgical approach depends on the location and etiology of compression, with consideration for extension of fusion if instability is present 1, 2

If Adjacent Segment Disease Without Cord Compression

Initial treatment should be nonoperative with physical therapy, NSAIDs, and activity modification for 6-12 weeks. 2

• Surgical intervention is indicated only if conservative management fails and there is documented nerve root compression correlating with symptoms 2
• Decompression with fusion extension is the mainstay of operative treatment when surgery becomes necessary 2
• Isolated decompression without fusion should only be considered in highly selected cases without radiographic instability 2

If Proximal Junctional Failure is Present

Revision surgery with extension of fusion is required when PJF causes progressive deformity or neurological compromise. 4

• The revision construct must extend to a more stable proximal anchor point, typically 2-3 levels above the original fusion 4
• Concurrent hip pathology must be addressed with muscle release or arthroplasty if severe contracture is present, as this prevents compensatory mechanisms needed for ambulation 4

Critical Pitfalls to Avoid

• Do not attribute symptoms to "normal post-fusion changes" without obtaining urgent imaging, as delayed diagnosis of cord compression leads to irreversible neurological damage 1, 3
• Do not perform isolated decompression at adjacent segments without assessing for instability, as this can worsen biomechanical stress and lead to progressive deformity 2
• Do not overlook hip joint pathology in patients with long fusion constructs, as severe hip contracture disrupts compensatory mechanisms and causes unexpected ambulatory decline after spinal fusion 4
• Do not delay surgical intervention when progressive myelopathy or cauda equina syndrome is present, as outcomes deteriorate rapidly with prolonged compression 1, 6

Prognosis and Counseling

• Adjacent segment disease develops in a substantial proportion of patients after spinal fusion, with etiology related to both natural disease progression and increased biomechanical stress 2
• Patients with extensive fusions who develop severe hip pathology face particularly high risk of ambulatory decline and PJF due to loss of compensatory spine movement 4
• Surgical outcomes for adjacent segment disease are generally favorable when appropriate indications are met, though revision surgery carries higher complication rates than primary procedures 2