Schwannomas are often intradural extramedullary benign lesions accounting to near 30% of spinal tumors and the intraspinal are rare, with diagnostic challenges, and are better managed under the intraoperative neurophysiological monitoring (IONM).1-8 We have read two novel articles on Spinal-Schwannoma Postoperative Neurological Deterioration Scoring System (SPNDSS), which predicts risks of neurological deficits.2,5 Aydin SO et al. commented on the role of SPNDSS classification utilized during the surgical planning of the spinal schwannomas, besides the reviewed data of 114 patients who underwent an operative management for these neoplasms between 2008 and 2021.2 The patients were 50% of each gender and the tumor sites were lumbar (56), cervical (24), thoracic (15), thoracolumbar (8), sacral (8), lumbosacral (2), and cervicothoracic (1). Operated schwannomas were categorized in seven groups; and the types 1 and 2 were treated by posterior midline approach; the type 3 by posterior midline and extraforaminal approaches; the type 4 by extraforaminal approach; the type 5 by extraforaminal approach and facetectomy; the type 6 by hemilaminectomy and extraforaminal approach; and the type 7 by posterior midline approach, besides the partial sacrectomy and/or corpectomy. The authors stressed microsurgery as the first option to treat spinal schwannomas, with preoperative planning based on the site, size and relation with surrounding structures.2 Liu Z et al. retrospectively evaluated the risk factors related to postoperative neurological deterioration rates, by the SPNDSS classification, in 203 patients with non-syndromic spinal schwannomas and underwent the surgery from January 2013 to December 2021.5 The study included 107 men and 96 women, the mean age was 52.6 (±14.2) years; preoperative symptoms were local pain (79.8%), paresthesia (37.9%), motor deficit (23.6%), and radiating pain (13.3%), with mean duration of 10.6 months for all patients.5 The registered preoperative neurologic deficits included back pain, radiating pain, motor weakness, sensory disturbance of the limbs, gait disturbance, and urinary disturbance, and the patients were randomly divided into a modeling (149) and a validation cohorts (54); after the spinal surgery procedures their clinical follow-up had the duration of 12 months.5 The modeling group had 79 men and 70 women, with mean age of 53 (22-68) years; 77.35% cases with neurological deterioration improved, and 24.53% totally recovered. The sites of schwannoma were lumbar (39.4%), thoracic (26.1%) and cervical (17.7%); 26.1% of patients had neurological deterioration, and 8.3% had recurrence in follow-up.5 Five data were used for scoring: duration of preoperative symptoms (1 point), radiating pain (2 points), tumor size (2 points), tumor site (1 point), and dumbbell tumor (1 point). Patients were grouped as low risk (0-2 points), intermediate risk (3-5 points), and high risk (6-7 points), with respective predicted neurological deteriorations of 8.7%, 36%, and 87.5%; and validation cohort confirmed the predicted risks of 8.6%, 46.4%, and 66.6%. The authors highlighted that the SPNDSS is a very useful tool to predict the risk of postoperative neurological deterioration in the operated spinal schwannoma patients, and favoring the stratification and management of both the higher-risk and lower-risk groups.5 In this setting, one should comment on articles about intramedullary schwannoma.
