Relevance of nerve root sacrifice for spinal foraminal and/or dumbbell schwannomas

Abstract-Text deutsch

English

Abstract-Text englisch

Objective: To achieve total resection in surgical treatment of spinal schwannoma, avoiding thus the risk of recurrence, involved root resection is usually needed. In contrast to pure intradural lumbar schwannoma, root sacrifice for intra-foraminal and/or dumbbell schwannoma is controversy regarding the risk for motor function. The aim of the study is to confirm the safety and benefits of nerve root section in the treatment of intra-foraminal/dumbbell spinal schwannoma.

 

Methods: All spinal schwannomas with foraminal extension who underwent surgical resection from 2014 to 2021 in our institution were collected. Tumor size, scalloping of vertebral body and enlargement of the intervertebral foramen on MRI were measured. Preoperative and postoperative clinical findings (neurological status) were also collected. Operative complications and long-term outcome were analyzed. 

 

Results: A series of 23 patients were included in the study. Between these, 8 (34%) were dumbbell-shaped schwannomas. 6 cases (26 %) were located in the cervical spine, 4 (17 %) in the thoracic spine, and 13 (57 %) in the lumbosacral spine.

The most common preoperative symptom was the pain (16 pts, 69%). 7 patients (30%) presented sensory disturbance and 9 (39%) had motor weakness (MRC 4/5). 2 patients presented urinary bladder dysfunction. Pyramidal signs were observed in 1 patient.

 The involved nerve root was cut in all cases. Complete resection was achieved in 20/23 patients. No recurrence was observed in patients with complete resection.

Two patients, which presented dumbbell schwannomas with extensions into myofascial structures, complained of immediate new postoperative motor deficit. One of them recovered quickly within 3 months. The other patient had severe paresis of the dorsiflexion of the foot persistent at 3 months, and partial recovery at one year follow up (MRC 4-/5). 

Post-operative radicular sensory disturbances described were: hypoesthesia in 6 patients (26%) and dysesthesia and hyperesthesia in 2 patients (8%). In all these cases the sensory deficits were non disabling.

Neuropathic pain was reported in 3 cases (13%): 1 patient needed medical treatment; 1 patient showed refractory neuropathic pain with lack of response to medical treatment. In the latter case a spinal cord neurostimulator was implanted.

 

Conclusion:  In the patients examined in our study, sacrifice of the foraminal root (both ventral and dorsal components) permitted to achieve total tumor resection, complying the oncologic rules and reducing the risk of tumor recurrence. Also, based on collected data, the incidence of nerve dysfunction is very low and acceptable, and when it occurs, good recovery at follow up has been observed.