A series of cases of corrective surgery in children with severe scoliosis due to spinal muscular atrophy (SMA) type 1 showed a positive success rate, but with significant postoperative complications.
As the life expectancy of 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 present with longer-term SMA complications, such as severe scoliosis, which must are managed. A case series published in Anesthesia Reports shows 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 about 60% of known cases. Patients usually show symptoms before 6 months of age and usually cannot sit unaided. Before nusinersen, SMA1 patients had a life expectancy of less than 2 years.
A complication previously unseen in patients with this SMA subtype before improved survival rates, kyphoscoliosis, was the focus of the case series. Four SMA1 patients (3, 4, 5 and 7 years) underwent kyphoscoliosis correction surgery between July 2020 and June 2021. Researchers reported pre-, intra-, and postoperative patient characteristics in an effort to gain more insight into a procedure that is lacking published literature on this particular patient population.
In scoliosis correction surgery associated with neuromuscular disease in general, complications such as respiratory failure, surgical site 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 under fluoroscopy after the procedure. This is crucial, as nusinersen is always administered through a lumbar puncture.
Two of the 4 patients previously had difficulty with tracheal intubation via direct laryngoscopy, so a hyperangular videolaryngoscopy was used as a first-line approach and was successful. These patients allowed facemask ventilation and oxygenation.
Respiratory complications are typical of SMA, but all patients returned to their respective baselines within 24 hours of surgery. All 4 required hospitalization for respiratory distress at some point in the year prior to surgery, and all 4 required non-invasive ventilatory support at night. No postoperative respiratory complications were reported, but patient A presented intraoperative ventilation challenges that were mitigated by endobronchial aspiration of respiratory secretions.
All 4 patients had complications after surgery, which the authors say 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 requiring three additional surgeries; wound opening, infection and metal exposure requiring 6 additional surgeries over 5 months; and spine protrusion one month after surgery with skin breakdown.
While the surgeries were successful and nusinersen courses could be resumed, the potential for serious complications warrants an in-depth discussion between guardians and health care teams prior to making the decision to correct kyphoscoliosis, the study authors conclude.
“As more children with SMA1 receive treatment with nusinersen, more will be present for scoliosis correction surgery,” they wrote. “With the risk of prolonged recovery, surgical and anesthetic complications, a detailed discussion of the risks and benefits should be conducted with the guardian before performing such procedures.”
Kong Kam Wa T, Holmes C, O’Brien K. A case series of pediatric patients with spinal muscular atrophy type I undergoing scoliosis correction surgery. Anaesth Rep. Published online Nov 17, 2021. doi:10.1002/anr3.12138