CR1-177
Anesthetic Considerations for Spinal Muscular Atrophy Patients Undergoing Spinraza Therapy
Henderson A, Elizabeth D, Obermeier L, Simpao A, Dubow S
Children's Hospital of Philadelphia, Philadelphia, PA, USA
Introduction: Nusinersen (Spinraza) gained FDA approval in December 2016 as the first pharmacological treatment for spinal muscular atrophy (SMA), a motor neuron disorder caused by a defect in the SMN1 gene that is necessary for muscle survival. SMA results in loss of motor neurons and muscle weakness; SMA subtypes 1-4 are based on age of onset and disease severity. Spinraza is given intrathecally and increases SMN protein levels by altering the splicing of SMN2 messenger RNA.
Case Series: Fifty-two patients ages 3 months to 36 years with SMA types 1-3 were selected for Spinraza therapy, and 44 underwent lumbar puncture (LP). The dosing schedule was 4 loading doses on days 1, 15, 29, and 58 followed by doses every 120 days. Starting dates were staggered to optimize use of hospital resources while adhering to the dosing regimen. Each patient had a pre-LP evaluation by anesthesiology, neurology, and pulmonology, and an anesthesia nurse practitioner (NP) assigned to provide continuity of care. LP was scheduled for the operating room, procedure room, or interventional radiology (IR) based on the patient’s respiratory status and the anticipated difficulty of LP. Patients were asked to bring any home non-invasive ventilation, and respiratory therapy was available at each location. Patients were encouraged to drink clears until 2 hours prior to arrival. Before the LP, an IV was placed, hydration was begun, a platelet level was checked, and topical lidocaine was applied.
Anesthetics varied from anesthesia standby to general anesthesia with a supraglottic airway in 3 patients. Fifteen patients were managed only with midazolam, propofol, or dexmedetomidine and a natural airway, while 11 received sevoflurane for at least 1 LP. Two patients had a tracheostomy, and 2 used their home BiPAP. By neurology protocol, patients had to lie flat for 1 hour and were observed for 4 hours after their first injection and 2 hours after later injections. No patients required escalation of care due to respiratory support. Complications included pain at injection site, vomiting, and mild headache requiring only supportive care. Three patients had unsuccessful LPs: 2 required IR, and 1 with a posterior spinal fusion needed a laminectomy that was complicated by a dural tear and CSF leak requiring an ICU stay.
Discussion: Reviewing our first 52 Spinraza cases has provided three main insights. First, a comprehensive perioperative program can successfully screen and prepare SMA patients for therapy and allocate resources efficiently. Dedicating an NP to each patient minimized follow-up time and provided a stable anesthesia resource for communication. Second, while SMA patients with thoracic insufficiency are particularly vulnerable to post-anesthesia respiratory issues, nearly all of our patients tolerated their brief anesthetic well and were discharged home after observation (which is now 2 hours after the first injection and 1 hour after later injections). Third, while scoliosis and spinal hardware in SMA patients can result in challenging LPs, 9 patients ages 10 years and older tolerated all LPs with only local anesthesia and midazolam, and 9 patients who initially needed anesthesia required only midazolam and a Child Life specialist on subsequent injections.
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