From the Guidelines
Stereotactic radiosurgery (SRS) is the recommended treatment for schwannoma in the posterior compartment, particularly for smaller tumors (<3cm), due to its high tumor control rates and better facial nerve preservation compared to microsurgical resection (MR) or conservative surveillance (CS) 1. A schwannoma in the posterior compartment is a benign tumor that develops from Schwann cells, which form the myelin sheath around peripheral nerves. These tumors typically occur in the posterior fossa of the skull, particularly involving the vestibular portion of the eighth cranial nerve (vestibular schwannoma or acoustic neuroma). Some key points to consider in the management of schwannoma in the posterior compartment include:
- Tumor size and symptoms: smaller, asymptomatic tumors may be monitored with regular MRI scans, while symptomatic or growing tumors require intervention 1.
- Treatment options: SRS, MR, and CS are available, with SRS offering high tumor control rates and better facial nerve preservation 1.
- Importance of early diagnosis: smaller tumors have better outcomes with treatment, and early detection can improve quality of life 1.
- Nerve preservation: these tumors grow from the nerve sheath rather than nerve tissue itself, which sometimes allows for preservation of nerve function during treatment 1. Key symptoms of schwannoma in the posterior compartment include:
- Progressive unilateral hearing loss
- Tinnitus
- Balance problems
- Facial numbness or weakness It is essential to weigh the benefits and risks of each treatment option, considering factors such as tumor size, patient health, and potential side effects, to determine the best course of treatment for each individual case 1.
From the Research
Schwannoma Posterior Compartment
- A schwannoma is a rare lesion that may develop in the spinal canal, in the area of the ganglion situated posterior to the articulation, in the extraspinal area or in a combination of these sectors 2.
- The surgical removal of these lesions is delicate because of the intimate relationships the schwannomas develop with the vertebral artery 2.
- A posterior midline approach can be used to remove C2 schwannomas, which takes advantage of the predominantly extradural development of these tumors 2.
- This approach involves the debulking of the posterior articular sector of the tumor, which is easily accessible through a midline posterior approach and necessitates minimal bone removal 2.
- In most cases, removal of the homolateral posterior arch of C1 is sufficient to create an adequate access for dissecting both the intradural and extraspinal sectors of the schwannoma 2.
Surgical Management
- The surgical management of schwannomas requires a spectrum of approaches, including endoscopic endonasal approaches 3.
- Endoscopic endonasal approaches appear to be well suited for trigeminal schwannomas restricted to Meckel's cave and/or extracranial segments of the nerve 3.
- Lateral transcranial skull base approaches should be considered for patients with posterior fossa disease 3.
- A new comprehensive classification for spinal schwannomas based on their presumed origin can help plan a surgical approach and predict its outcome 4.
Classification and Treatment
- Classification guides the surgical approach and predicts prognosis, and a new classification with 9 types was created by analyzing the anatomy of spinal nerves and the origin of significant tumor portions and cystic components in preoperative magnetic resonance images 4.
- Gross total removal rates reached 88.0% overall, with type 1 and type 2 tumors at 95.3% and 96.0% respectively 4.
- The approach varied with tumor type, with laminectomy predominantly used for types 1,2, and 9, and facetectomy with posterior fixation used for type 3 tumors 4.
- Radiation-induced benign peripheral nerve sheath tumors are uncommon late complications of irradiation, and complete surgical resection is the main stay for the treatment of these tumors 5.