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Spondylolisthesis: Approach and Treatment by Meyerding Grade

The Meyerding Grading Scale

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Additional Measurements Used Alongside Meyerding Grading

• Slip angle (normally <0°, indicating lordosis at L5–S1): measures lumbosacral kyphosis; >10° is a risk factor for progression
• Sacral inclination (normally >30°)
• Pelvic incidence (PI) (normally ~50°; elevated to 70–80° in spondylolisthesis patients): does NOT predict progression but predicts sagittal alignment demands

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Wiltse-Newman Classification (Etiologic Types)

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General Surgical Indications (Any Grade)

• Progression of slip (especially in skeletally immature patients)
• Neurologic deficit or persistent severe radiculopathy/weakness despite conservative care
• Intractable pain unresponsive to ≥3–6 months of nonoperative treatment
• High-grade slip (≥Grade III) in a growing child → prophylactic fusion recommended

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Grade-by-Grade Approach

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Grades I & II (Low-Grade: 0–50%)

Nonoperative Treatment (First-Line)

• Activity modification: restriction from high-risk sports (gymnastics, football linemen, weightlifting)
• Grade I asymptomatic: may return to contact sports once symptom-free
• Grade II asymptomatic: restricted from extension-dominant activities (gymnastics, football)
• Exercise: flexion-based core strengthening, hamstring stretching
• NSAIDs for pain control
• Bracing: considered for acute pars stress reactions, especially in adolescents
• Serial radiographic surveillance in skeletally immature patients to detect progression

Operative Treatment (When Conservative Fails)

• Reserved for intractable pain, progressive slippage, or neurologic compromise
• Procedure of choice: L5–S1 posterolateral in situ fusion (for isthmic/pediatric)
• The Wiltse paraspinal muscle-splitting approach to the lumbar transverse processes and sacral alae is widely used
• L5 radiculopathy is uncommon in children with low-grade slips; decompression is rarely needed
• Pars repair (Buck lag screw or Bradford tension band wiring + bone graft) is an option in young patients with <10% slip and a pars defect at L4 or above (spares L5–S1 motion segment)
• For adult isthmic Grade I/II: foraminal decompression + in situ posterolateral L5–S1 fusion ± instrumentation

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Grades III, IV & V (High-Grade: >50% including Spondyloptosis)

Presentation

• More symptomatic with higher rate of progression
• L5 radiculopathy (exiting nerve root) — not S1 (distinguish from L5–S1 HNP)
• Cauda equina dysfunction (especially in dysplastic type where the neural arch is intact)
• Lumbosacral kyphosis, palpable step-off, hamstring tightness, altered gait ("pelvic waddle"), "heart-shaped" buttocks

Operative Treatment (Strongly Recommended)

• Prophylactic fusion is recommended in growing children with >50% slip (Grades III–V)
• Standard procedure: bilateral posterolateral fusion in situ, L4–S1 (with or without instrumentation)
  • L4 must be included because L5 is too far anterior to achieve solid L5–S1 fusion at high grades
• Nerve root exploration/decompression: controversial; reserved for patients with clear-cut radicular pain or significant weakness
• Other described procedures:
  • Posterior decompression + fibular interbody fusion + posterolateral fusion without reduction (Bohlman technique — excellent long-term results)
  • L5 vertebrectomy (Gaines resection): for spondyloptosis (Grade V), involves removing L5 and fusing L4 to the sacrum

Reduction of the Listhesis — Controversial

• Carries a 20–30% incidence of L5 nerve root injury (most transient)
• Indications:
  • Cosmetically unacceptable deformity
  • Severe lumbosacral kyphosis (slip angle so severe that posterior fusion would be under tension without correction)
  • In situ fusion at high-grade leaves such severe compensatory hyperlordosis above the fusion that long-term problems are common
• Close intraoperative and postoperative neurologic monitoring is mandatory

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Degenerative Spondylolisthesis (Type III — Typically Grade I)

• Neurogenic claudication (central stenosis): leg heaviness/cramping, improved with flexion ("shopping cart sign")
• Nerve root compression (lateral recess stenosis): traversing L5 root compression between subluxated inferior facet of L4 and the posterosuperior body of L5

• Nonoperative: same as lumbar stenosis — activity modification, NSAIDs, physical therapy, epidural steroid injections
• Operative: decompression of nerve roots + posterolateral fusion with or without instrumentation
• SPORT Trial evidence: At 4-year follow-up, surgical patients had significantly better SF-36 Bodily Pain, Physical Function, and Oswestry Disability Index scores compared to nonoperative patients (both groups improved from baseline)

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Summary Table

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• Miller's Review of Orthopaedics 9th Edition, pp. 775–778
• SPORT Trial (Weinstein et al., 2009) — cited in Miller's