[Anatomical rationale for surgical treatment of trigeminal neuralgia combined with cerebellopontine angle tumors]

[Anterior transpetrosal (Kawase) approach for petroclival meningioma with trigeminal neuralgia: case report and literature review]

The authors present a patient with petroclival meningioma complicated by trigeminal neuralgia. Resection of tumor via anterior transpetrosal approach with microvascular decompression of the trigeminal nerve was performed. A 48-year-old female patient presented with left-sided (V1-V2) trigeminal neuralgia. Magnetic resonance imaging revealed a tumor 33´27´25 mm with a base adjacent to the top of petrous part of the left temporal bone, tentorium cerebelli and clivus. Intraoperative examination revealed true petroclival meningioma extending to trigeminal notch of petrous part of temporal bone. There was additional compression of trigeminal nerve by caudal branch of superior cerebellar artery. Total resection of tumor was followed by disappearance of vascular compression of trigeminal nerve and regression of trigeminal neuralgia. Anterior transpetrosal approach provides early devascularization and resection of true petroclival meningioma, as well as wide imaging of anterolateral surface of the brainstem, identification of neurovascular conflict and vascular decompression.

[Etiopathogenetic substantiation of surgical treatment of neurogenic pain syndromes]

The purpose of the study was to improve classification of neurogenic (neuropathic) pain syndromes. This will make it possible to define the indications for appropriate analgesic surgery for each type of drug-resistant neurogenic pain syndrome. Incorrect management of neurogenic pain syndromes is usually associated with underestimation of pathogenetic prerequisites for its occurrence. Differentiation of compression, deafferentation and mixed neurogenic pain syndromes makes it possible to determine appropriate surgery and avoid tactical errors. Moreover, this approach allows you to save patients from unreasonable long-standing suffering. Patients with chronic pain syndromes often become disabled, sometimes in the prime of life, and isolated from society and family. Therefore, treatment of chronic pain is currently an urgent problem.

Dysfunctions and anatomical relationships of cranial nerves in epidermoids of the cerebellopontine angle

OBJECTIVE

To evaluate the correlation of neurological symptoms with anatomical relationships of cranial nerves, lesions and vessels in patients with epidermoids of the cerebellopontine angle.

MATERIAL AND METHODS

We analyzed neurological symptoms, magnetic resonance data, intraoperative findings and postoperative functional outcomes in 25 patients (14 females and 11 males aged 22-77 years) with epidermoids of the cerebellopontine angle.

RESULTS

Cranial nerve dysfunctions were noted in 15 patients. Involvement of cochlear (n=9) and trigeminal (9 cases including 4 ones with sensory impairment and 5 patients with neuralgia) nerves was the most common. There were 10 patients with ataxia, hemiparesis and seizures without cranial nerve dysfunction. In 15 patients, epidermoids spread to supratentorial space and contralateral cerebellopontine angle. Lesion-induced brainstem compression was found in 22 cases. Cranial nerves and cerebellar arteries were partially or completely enclosed by lesion in all cases. Severe compression and dislocation of the nerve root entry/exit zone were found in all cases. One patient with trigeminal neuralgia had vascular compression of trigeminal nerve caused by superior cerebellar artery. Total resection was achieved in 16 patients. Small capsule remnants were left on vessels, nerves or brainstem in 9 patients. Postoperative complete or partial restoration of cranial nerve functions was noted in 11 cases. Deterioration of preoperative neurological deficit in 4 patients and postoperative neurological symptoms de novo in 3 patients were temporary.

CONCLUSION

Cranial nerve dysfunctions are caused by compression of the nerve root entry/exit zones by epidermoids of the cerebellopontine angle. Surgical intervention is effective in alleviating symptoms of cranial neuropathy and brainstem compression. Vascular decompression should be performed in patients with trigeminal neuralgia.

[Trigeminal radiculopathy in vestibular schwannomas]

OBJECTIVE

To evaluate the correlation of trigeminal radiculopathy with anatomical relationships of trigeminal nerve root, brainstem, tumors and vessels in patients with vestibular schwannomas.

MATERIAL AND METHODS

A retrospective analysis included 153 patients (106 females and 47 males aged 22-82 years) with vestibular schwannomas who underwent surgery via retromastoid approach. Preoperative trigeminal radiculopathy (facial pain and sensory disturbances) was examined after microsurgical resection. Brainstem compression was analyzed by comparison of transverse size of contralateral to vestibular schwannoma half of brainstem and ipsilateral side.

RESULTS

Tumor-induced brainstem and trigeminal nerve compression was found in 115 cases. Sixty-four of these patients had trigeminal radiculopathy symptoms. Degree of brainstem compression was significantly higher in trigeminal radiculopathy group. Facial hypoesthesia was found in 61patients, trigeminal neuralgia - in 5 cases, neuropathic pain - in 3 patients. Thirty-seven patients without brainstem compression had no trigeminal nerve involvement. One patient had trigeminal neuralgia following compression by superior cerebellar artery. Total resection with brainstem and trigeminal nerve decompression were performed in all cases. Isolated or combined compression of trigeminal nerve root was noted in 9 patients with trigeminal neuralgia and neuropathic pain, in 2 with facial numbness and in 2 patients without trigeminal symptoms. In case of trigeminal neuralgia following compression by superior cerebellar artery, vascular decompression was performed only in patients with facial pain and numbness. Facial pain completely resolved in all patients. Complete or partial sensory restoration was noted in 25 cases. No facial sensory disorders were noted in 26 cases, transient sensory deterioration - in 10 patients.

CONCLUSION

Trigeminal radiculopathy is caused by severe brainstem compression following vestibular schwannomas and usually results sensory disturbances and rarely facial pain. The impact of tumor on trigeminal nerve root and brainstem trigeminal pathways can be accompanied by vascular compression by superior cerebellar artery. Regression of trigeminal radiculopathy symptoms after resection of vestibular schwannoma is caused by decompression of trigeminal nerve root and brainstem. In case of concomitant neurovascular syndrome, vascular decompression is indicated.

[Trigeminal nerve lipoma presenting with trigeminal neuralgia: case report and literature review]

Cerebellopontine angle lipomas are benign mass lesions and rarely result trigeminal neuralgia. A 61-year-old male with right-sided trigeminal neuralgia in V2 and V3 divisions without sensory disturbances is reported in the article. MRI revealed mass lesion 11´11´4 mm on the lateral pontine surface spreading to the right trigeminal nerve root entry zone. No signs of neurovascular compression were found. Microsurgical exploration of the cerebellopontine angle showed a fatty mass adherent to the brainstem with incorporation of inferior part of trigeminal nerve root. Fatty tissue resection was followed by partial sensory trigeminal rhizotomy. Histological examination identified lipoma. Postoperative MRI showed small residual tissue with minimal ischemic area near trigeminal nerve root entry zone. Mild hypoesthesia within V2 and V3 trigeminal branches occurred after surgery. Trigeminal neuralgia completely resolved, and medications were discontinued. This clinical case and literature review clearly demonstrated successful elimination of trigeminal neuralgia in patients with cerebellopontine angle lipoma after resection of mass lesion and partial trigeminal rhizotomy.