Anatomical relationship between the foramen ovale and the lateral plate of the pterygoid process: application to percutaneous treatments of trigeminal neuralgia

Neurosurgical Review (2022) 45:2193–2199

Our aim was to clarify the variations in the positional relationship between the base of the lateral plate of the pterygoid process and the foramen ovale (FO), which block inserted needles during percutaneous procedures to the FO usually used for the treatment of trigeminal neuralgia.

Ninety skulls were examined. The horizontal relationship between the FO and the posterior border of the base of the lateral plate of the pterygoid process was observed in an inferior view of the skull base. Skulls that showed injury to either the FO or the lateral plate of the pterygoid process on either side were excluded.

One hundred and sixty sides of eighty skulls were eligible. The relationship between the FO and the posterior border of the base of the lateral plate was classified into four types. Among the 160 sides, type III (direct type) was the most common (35%), followed by type I (lateral type, 29%) and type IV (removed type, 21%); type II (medial type) was the least common (15%). Of the 80 specimens, 53 showed the same type bilaterally.

In type IV, the posterior border of the base of the lateral plate is disconnected from the FO, so percutaneous procedures for treating trigeminal neuralgia could fail in patients with this type.

Minimally Invasive Trigeminal Ablation: Novel Transoral Technique for Targeted Treatment of V3

World Neurosurg. (2018) 118:193-196

Trigeminal neuralgia (TN) is a chronic orofacial pain syndrome that presents with debilitating shooting pains in the V3 nerve distribution. The condition is traditionally responsive to anticonvulsant therapy; however, cases that become refractory to medications often require surgical intervention.

CASE DESCRIPTION: We present a case of TN that was treated with minimally invasive trigeminal ablation. The patient presented with a 6-year history of TN that had been resistant to medical management. The patient opted for minimally invasive management, refused stereotactic radiosurgery, and was treated using the minimally invasive trigeminal ablation approach. At 16 weeks postoperatively, the patient reported complete alleviation of pain with minimal sensorineural numbness.

CONCLUSIONS: The endoscopic approach allows for precise targeting through visual guidance, which is ideal in patients undergoing neuroablation for pain within specific nerve distributions. This is the first documented case of an endoscopic minimally invasive transoral approach toward ablative TN management.

Trigeminal neurinomas with extracranial extension: analysis of 28 surgically treated cases

J Neurosurg 113:1079–1084, 2010.DOI: 10.3171/2009.10.JNS091149

The object of this paper was to review the authors’ experience with 28 cases of trigeminal neurinomas having an extracranial extension.

Methods. The authors analyzed 28 cases of trigeminal neurinoma in which there was an extracranial extension of the tumor. All patients were treated in their department between the years 1989 and 2009.

Results. There was tumor extension along the ophthalmic division of the nerve in 4 cases, along the maxillary division in 5, and along the mandibular division in 13. In 6 tumors there was diffuse extracranial extension and the exact extracranial division of nerve involvement could not be ascertained. In 10 cases, the tumor had a multicompartmental location—in the posterior fossa, the middle fossa, and the extracranial compartment. Tingling paraesthesiae, numbness, and diffuse pain in the distribution of the trigeminal nerve were common symptoms and were present in 90% of patients. The extracranial component had a well-defined perineural/meningeal membrane cover that was continuous with the middle fossa dura mater and isolated the tumor tissue from the adjoining critical structures. In 7 out of 10 cases, even the posterior fossa component of the tumor was entirely “interdural” (within the confines of the dura). The maximum dimension of the tumor was > 4 cm in 22 cases. A limited “transcranial” approach with (12 cases) or without (16 cases) zygomatic osteotomy was found suitable for resection of these tumors. In 4 cases a lateral orbitotomy was performed. Total tumor resection was performed in 20 cases and partial resection in 8. The duration of follow-up ranged from 6 months to 19 years. Two patients required additional surgery for symptomatic recurrence.

Conclusions. Extracranial extensions of trigeminal neurinomas have a well-defined meningeal covering. In most cases resection was performed via a minimally invasive cranial avenue (a “reverse skull base approach”). Radical resection was associated with an excellent long-term outcome.