A case series of corrective surgeries in children with severe scoliosis due to spinal muscular atrophy (SMA) type 1 showed a positive success rate, but with significant postoperative complications.
As life expectancy for pediatric patients with severe spinal muscular atrophy type 1 (SMA1) increases in the wake of the development and approval of the antisense oligonucleotide nusinersen, more of these patients are presenting with longer-term SMA complications, such as severe scoliosis, that must be managed. A case series published in Anaesthesia Reports demonstrates the risk of complications after spinal surgery to correct severe scoliosis in patients with SMA1.
SMA phenotypes range from type 0 (most severe, prenatal onset) to type 5 (adult-onset with milder symptoms). SMA1 is the most common, accounting for approximately 60% of known cases. Patients typically show symptoms before 6 months of age and are typically unable to sit without assistance. Before nusinersen, SMA1 patients had a life expectancy of less than 2 years old.
One complication previously unseen in patients with this SMA subtype before improved survival rates, kyphoscoliosis, was the focus of the case series. Four SMA1 patients (ages 3, 4, 5, and 7) underwent kyphoscoliosis correction surgery between July 2020 and June 2021. Researchers reported pre-, intra-, and post-surgery patient characteristics in an effort to gain more insight into a procedure that lacks published literature concerning this particular patient population.
In scoliosis correction surgeries related to neuromuscular disease in general, complications such as respiratory failure, surgical wound infection, and urinary tract infection are higher than in otherwise healthy patients. All 4 procedures in the case series were successful, and all patients were able to resume intrathecal injections of nusinersen guided by fluoroscopy after the procedure. This is crucial, as nusinersen is always administered via lumbar puncture.
Two of 4 patients previously had difficulty with tracheal intubation via direct laryngoscopy, so a hyperangulated videolaryngoscopy was used as the first-line approach and was successful. Face mask ventilation and oxygenation were both possible in these patients.
Respiratory complications are typical of SMA, but all patients returned to their respective baselines within 24 hours after their surgeries. All 4 had required hospitalization at some point in the year prior to surgery for respiratory issues, and all 4 required non-invasive ventilatory support at night. No post-surgery respiratory complications were reported, but patient A presented intra-operative ventilation challenges that were mitigated by endobronchial suctioning of respiratory secretions.
All 4 patients had post-surgery complications, which the authors note is not uncommon. Complications included a lumbar cerebrospinal fluid (CSF) leak, which required surgical revision and 3 weeks of hospitalization; metal frame exposure, pain and instability that required three additional surgeries; wound opening, infection, and metal exposure that required 6 additional surgeries over 5 months; and spinal rod protrusion a month post-surgery with skin breakdown.
While the surgeries were successful and nusinersen courses could be resumed, the potential for serious complications warrants in-depth discussion between guardians and care teams ahead of making the decision to correct kyphoscoliosis, the study authors conclude.
“As more children with SMA1 receive nusinersen treatment, more will present for scoliosis correction surgery,” they wrote. “With the risk of a prolonged recovery, surgical and anesthetic complications, a detailed discussion regarding risks and benefits must be had with the guardian before undertaking such procedures.”
Kong Kam Wa T, Holmes C, O’Brien K. A case series of paediatric patients with spinal muscular atrophy type I undergoing scoliosis correction surgery. Anaesth Rep. Published online November 17, 2021. doi:10.1002/anr3.12138