The current criterion-standard treatment for schwannomas is intracapsular excision. This study was designed as a long-term follow-up to investigate postoperative symptoms, nervous impairment, and recurrence rate.
We performed a long-term follow-up of 18 subjects who underwent intracapsular schwannoma excision. We evaluated preoperative versus postoperative 2-point discrimination (2-PD) in the affected dermatome, pain (visual analog scale [VAS] from 0–10), Hoffmann-Tinel sign, and thermoreceptor response. For reasons of comparison, all examinations were done on both the healthy and affected extremity.
Last postoperative follow-up was done on average after approximately 50.4 months. Comparison between preoperative and postoperative sensibility testing (2-PD) in the affected dermatome showed a significant improvement of 22.7% after surgery (5-mm 2-PD; P = 0.02). Compared with the healthy nonoperated extremity preoperatively, subjects showed a significant sensory deficit of 40.9% (9-mm 2-PD; P < 0.000). Postoperatively, 12 of 18 subjects still showed a deficit in 2-PD. However, deficiency was decreased to 23.5% (mean, 4-mm 2-PD; P = 0.003). Through intracapsular schwannoma excision, subjects could drastically improve their pain (from VAS 6.7 to VAS 4.0).
During our examination, we clinically suspected recurrence in 3 subjects, which were sent to magnetic resonance imaging to rule out or confirm a recurrent tumor.
Many subjects reported ongoing pain and sensory deficits after intracapsular excision of schwannomas. Symptoms right after surgery may be due to iatrogenic nerve injury or residual deficits from compression damage of the tumor mass. As schwannomas are usually growing at a slow rate, early symptoms after a symptom-free period might possibly indicate scarring of soft tissue, which may cause signs of recurrent neurological deficits or pain. Patients with a late onset of symptoms are at the highest risk of having a true recurrence of schwannoma. None of the 3 suspected subjects showed radiological evidence for a recurrent schwannoma, but rather scarring and soft tissue adhesions to the nerve, which could explain the clinical findings.
Intracapsular removal of schwannomas is relatively easy to perform, does not cause any additional damage to the nerve in most cases, and is therefore an excellent method for treatment of symptomatic schwannoma patients.