Advantages of intra-capsular micro-enucleation of schwannoma arising from extremities

Schwannoma is the most common tumor of the peripheral nerves, with surgical enucleation being the established treatment modality. However, some schwannomas cannot be easily enucleated and this sometimes results in iatrogenic nerve injury even with atraumatic procedures. Here we present a retrospective review of the management of schwannoma in the extremities and compare clinical outcomes from the two techniques of extra-capsular and intra-capsular enucleation.

We reviewed 36 schwannomas from 35 patients who underwent surgical excision of schwannomas arising from the extremities. Twenty had undergone extra-capsular resection and 16 had undergone enucleation using the intra-capsular technique. The post-operative neurological deficits were graded as minor, major, and transient. The duration of symptoms, maximum tumor diameter and site of occurrence were compared between patients with the three grades of deficit.

In total, 22 patients developed no sensory changes following enucleation of schwannoma or only temporary and minor changes that had fully resolved within 6 months. Ten patients developed new neurological deficits following surgery that took longer than 6 months to resolve. Four patients experienced new motor deficits or paresthesia following operation that had still not recovered at the final follow-up, all of whom underwent enucleation using the extra-capsular technique. Neurological deficit after enucleation was significantly lower using the intra-capsular compared with the extra-capsular technique. Patient age, duration of symptoms, maximum diameter of the tumor and site of occurrence did not influence the neurological deficit following enucleation of schwannoma.

These results support intra-capsular micro-enucleation as a safe and reliable treatment for every type of schwannoma. To minimize the risk of nerve injury, en bloc resection should not be used because the main purpose of schwannoma surgery is the relief of symptoms, not tumor resection. Thorough pre-operative counseling of patients to inform them of the potential occurrence of neurological deficit is important.