Muscular Dystrophy Scoliosis - Posterior Spinal Fusion (T2-Pelvis)

Indication. Progressive neuromuscular scoliosis in Duchenne or Becker muscular dystrophy — a curve greater than 20–30 degrees that is documented to be progressing despite bracing — in a patient who still has adequate pulmonary function (FVC greater than 30–40 percent predicted) and adequate cardiac function (EF greater than 30 percent), and who retains a reasonable quality of life. Curves that have not progressed, and patients in whom cardiopulmonary reserve has already collapsed, are not served by surgery. Goals of surgery. Prevent curve progression, restore and maintain sitting balance, correct pelvic obliquity, ease nursing care and seating, and reduce back pain. Counsel families honestly that fusion does not halt the FVC decline — that tracks progressive muscle weakness, not the curve (Shapiro et al.). The indication is seating, comfort and deformity prevention, not respiratory preservation. Timing — the one decision that matters. Too early is unnecessary surgery; too late is prohibitive risk. The window balances four variables:

Pre-operative optimisation. Every DMD fusion is a multidisciplinary case. The cardiopulmonary work-up is the rate-limiting step and a perennial viva topic:

Consent specifically for the major risks: respiratory failure (20–30 percent), blood loss requiring transfusion (greater than 50 percent), infection (5–10 percent), neurologic deficit (1–3 percent), pseudarthrosis (10–20 percent), proximal junctional kyphosis (10–20 percent), dural tear (5–10 percent), and the honest statement that the operation will not preserve lung function. Setup. Prone on a Jackson table or chest rolls with the abdomen hanging free (reduces venous bleeding). Lines: arterial line for tight BP control and anticipated blood loss, Foley, core temperature, and neuromonitoring leads. Regional or neuraxial techniques are generally avoided; this is a general-anaesthetic, ICU-bound case.

The goal is a rigid, segmentally instrumented posterior fusion from T2/T3 to the pelvis that corrects the coronal curve and pelvic obliquity while protecting the spinal cord, nerve roots, great vessels and iliac vessels. The exposure is the long posterior midline subperiosteal dissection, laid out in full as the first steps below.

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ICU management (all DMD patients). Every DMD fusion goes to ICU for 1–3 days minimum, longer if respiratory support is needed. Most discharge by 5–10 days if uncomplicated; complications occur in 20–40 percent of cases. - Respiratory (highest priority): overnight ventilation is often needed; extubate when the patient is awake with a strong cough and good tidal volumes; use BiPAP if marginal; aggressive pulmonary toilet with incentive spirometry, chest PT and frequent suctioning; early mobilisation (sit day 1–2).

• Pain: multimodal — PCA opioids, gabapentin, acetaminophen; consider epidural or intrathecal morphine.
• Cardiac: continuous telemetry (cardiomyopathy risk) with arrhythmia surveillance.
• Neurologic: frequent exams every 2–4 hours initially; check motor and sensory in all extremities; watch for delayed deficit from epidural haematoma.
• Drains: remove when output is less than 30 mL per 8 hours (typically day 3–5).
• Mobilisation: sit day 1–2; transfer to wheelchair day 2–3 (most DMD patients are wheelchair-dependent); no brace is needed — the instrumented fusion is stable.
• Imaging: AP/lateral spine X-rays on day 1 to confirm instrumentation and alignment, then at discharge, 6 weeks, 3 months, 6 months, 1 year, then yearly until skeletal maturity and every 1–2 years after. Long-term monitoring. Watch for infection (fever, wound drainage, rising CRP/ESR), pseudarthrosis (pain, loss of correction, nonunion on X-ray/CT), instrumentation failure (screw pullout, rod fracture) and proximal junctional kyphosis. The functional goals are improved sitting balance and corrected pelvic obliquity, easier seating/transfers/nursing care, reduced back pain, and preserved quality of life — with the explicit caveat that FVC continues to decline with disease progression (Shapiro et al.). Complications

Epidemiology and natural history. Before glucocorticoid therapy, around 90 percent of boys with DMD developed a progressive scoliosis once wheelchair-dependent, with curves typically worsening by 1–2 degrees per month. Long-term glucocorticoids (prednisolone/deflazacort) have markedly reduced both the incidence and severity of scoliosis, shifting surgery to fewer, often older patients — this modern natural-history shift must be reflected in any contemporary discussion of timing (Connolly 2013; Birnkrant 2018 DMD Care Considerations). Why pelvic fixation, and how early? Sengupta et al. compared pelvic with lumbar-only (to L5) fixation in 50 DMD patients: lumbar fixation to L5 was adequate only when surgery was performed early, with small curves and pelvic obliquity under 10 degrees; pelvic fixation was required for larger curves and established obliquity, and carried higher blood loss (mean 4.1 L) and longer stay. The lesson: operate before pelvic obliquity is established, and use pelvic fixation once it is. The honest evidence base. The Cochrane systematic review (Cheuk 2015) found that of 49 relevant studies NONE were randomised or quasi-randomised — the entire evidence base for this operation is observational (case-series, Level IV). Families should therefore be counselled honestly: the benefits of fusion (seating, comfort, pelvic obliquity correction) are supported only by observational data, and there is no proof it prolongs life or preserves pulmonary function. Shapiro et al. (1992) showed the FVC decline continues post-operatively (mean 45.3 percent pre-op falling to 28.7 percent at around 3.3 years) — it tracks muscle weakness, not the curve. This nuance is highly examinable. Key evidence messages. (1) Operate in the window before pelvic obliquity and prohibitive cardiopulmonary risk. (2) Pelvic fixation is mandatory once obliquity is established. (3) The indication is seating and comfort, not respiratory preservation. (4) Glucocorticoids have changed who needs surgery.