Is routine intraoperative neuromonitoring necessary in growing rod lengthening procedures? A retrospective, observational study.

Abstract

To investigate whether intraoperative neuromonitoring (IONM) may be avoided in growing rod lengthening procedures in early onset scoliosis (EOS). A total of 636 primary growing rod surgeries and lengthening procedures were performed in 112 patients with EOS. Traditional growing rods (TGR) or magnetically controlled growing rods (MCGR) were implanted and subsequent lengthening procedures were done at stipulated intervals. Combined multi-modality IONM was used in all index surgeries-but was only used in lengthening procedures in patients with existing spinal cord abnormality or a history of neurosurgical procedure for the same, patients with prior history of a neuromonitoring alert in their index surgery and when lengthening was accompanied by an implant exchange/revision. All the remaining growing rod lengthening procedures were carried out without IONM. Hospital records and operation notes were retrospectively reviewed with focus on details of neurological events/complications. In 112 primary growing rod applications (TGR = 96, MCGR = 16) and 524 lengthening procedures (TGR = 444, MCGR = 80), intraoperative neuromonitoring 'alerts' were encountered in 6/112 index surgeries and temporary postoperative neurological deficits were seen in 2/112 index surgeries. No intraoperative neuromonitoring event or postoperative neurological complication was encountered in 524 lengthening procedures-irrespective of whether they were carried out along with implant exchange, or in patients with spinal cord abnormality or prior neuromonitoring event during index surgery. While IONM should be used in primary growing rod application surgeries, its use may be avoided in lengthening and implant exchange procedures in a resource-limited setting. Level 3.