We conducted a chart review of patients with genetically confirmed SMA types 2 or 3 seen in OHSU neuromuscular clinic between 2017-2018. 

Eighteen SMA patients were included, of those seven with type 2 and eleven with type 3, median age 36.6 (range 19-71). Seventeen were nonambulatory with a remarkable disability in strength worst in lower compared with upper limbs (%MRC of 28.1% and 54.7% respectively). Twelve had severe scoliosis, 10 required thoracolumbar fusion. Of those, six were referred for bone laminectomy for intrathecal access, three underwent procedure. Ten of 18 had significant respiratory impairment necessitating ventilation, one underwent tracheostomy. Eight were treated with Nusinersen for median of 7 months (range 1-15); seven exhibited stability in %MRC at 6 months, two demonstrated very modest improvement with %MRC change mean of 0.94% and 5% in upper and lower limbs respectively at 12 months.  A 19 year-old patient treated for 15 months demonstrated stability in %MRC at 12 and 15 months. One died shortly after treatment initiation from respiratory failure. In comparison, untreated patients’ %MRC remained stable. Seven patients declined treatment due to medical comorbidities, lack of data in adult SMA or advanced stage. Four patients are awaiting treatment. Side effects were as follows: 2 suffered from post lumbar puncture headache severe enough to require blood patch, 1 developed bacterial meningitis requiring admission for long term antibiotics.

The degree of impact on strength and function in adult SMA treated with Nusinersen remains unclear, and complications secondary to its intrathecal administration can be serious. More data is needed to better understand the role of Nusinersen in adult SMA patients.