Symptomatic small schwannoma is a risk factor for surgical complications and correlates with difficulty of enucleation

Postoperative neurological deficits of schwannomas are the complications that we want to avoid most. Predicting postoperative neurological deficits is crucial; however, the correlation between preoperative symptoms and neurological findings with postoperative neurological complications has not yet been completely clarified. Here we analyzed the risk factors for postoperative neurological complications. The study included 131 tumors from 107 patients histologically confirmed as schwannomas, which developed in the extremities and trunk without spinal cord involvement. The correlation between clinical findings and postoperative complications were statistically analyzed. One-hundred three tumors (78.6 %) had the preoperative neurological symptoms; these symptoms were detected in 93.3 % of small tumors (<4 cm(3)). We defined it as follows about the anatomical location of schwannomas. One is “central type” that normal nerve bundles widely splayed over the tumor’s capsule (tumor located in the central region of the nerve). Another is “peripheral type” that easy to enucleate without neurolysis (tumor located in the peripheral region of the nerve). Static analysis showed a significant difference in the Tinel sign, numbness, and postoperative neurological deficits (p = 0.04, 0.006, p < 0.001, respectively). Twenty-one cases (16.0 %) showed new postoperative neurological symptoms, including numbness in 12 cases, dysesthesia in three cases, pain in three cases, and slight motor palsy in two cases. In statistical analysis, small tumors (<4 cm(3)) significantly correlated with Tinel sign (p < 0.001), and was marginally significant with postoperative neurological deficits (p = 0.05). Moreover, small tumors (<4 cm(3)) accompanying numbness preoperatively significantly correlated with postoperative neurological deficits (p = 0.04). Small (<4 cm(3)) tumors significantly correlated with the preoperative neurological symptoms. Those tumors accompanying numbness also significantly correlated with the difficulty of the enucleation and postoperative neurological deficits. These findings will help to predict the neurological complication.