Anaesthetic considerations in posterior instrumentation of scoliosis due to spinal muscular atrophy: Case series of 56 operated patients

Background Spinal muscular atrophy (SMA) is a rare illness that often leads to severe kyphoscoliosis. This case series adds to the heretofore sparse information as regards the anaesthetic management of SMA scoliosis patients. Methods This retrospective study reviewed the charts of 79 SMA patients (type II n = 34 and type III n = 45) presenting for possible scoliosis surgery during the time period 2007-2019. Special attention focused on preoperative assessment and clearance requirements, anaesthesia protocol and postoperative handling. Results Out of 79 patients, 17 did not receive clearance for the procedure mostly due to grave respiratory insufficiency. Out of 62 patients with clearance for both surgery and anaesthesia, 56 patients [44 females, 12 males; age mean +/- SD (range) 22 +/- 7.3 (10-40) years] underwent the procedure. Their forced vital capacity and forced expiratory volume in 1 s were mean +/- SD (range) 1.41 +/- 0.53 (0.61-2.65) L and 1.26 +/- 0.47 (0.52-2.27) L, respectively. Intubation difficulties and their resolution, e.g. with the help of fibreoptic technique and video laryngoscopy, are described. All 56 patients were extubated in the operating room postoperativley. Patients stayed at the postanaesthesia care unit for one (n = 48) or two (n = 8) nights. A considerable amount of the patients (19/56) developed hypokalaemia postoperatively. Conclusion This analysis is one of the bigger series of its kind and adds insight into the preoperative clearance process, the anaesthetic protocol and some of the postoperative complications, e.g. the tendency for developing postoperative hypokalaemia which has not been reported previously.