Posterior Intradural Petrous Apicectomy and Total Sensory Trigeminal Rhizotomy for Residual Trigeminal Schwannoma with Secondary Trigeminal Neuralgia

Introduction: Secondary trigeminal neuralgia (STN) is an uncommon disorder that could be associated with cerebellopontine angle tumors. Treatment is challenging; therefore, alternative surgical procedures should be considered. Posterior intradural petrous apicectomy (PIPA) allows resection of Meckel's cave tumors, exposes the trigeminal nerve, and allows total sensory trigeminal rhizotomy (TSTR), an uncommon technique that could be used in refractory TN.

Case: A 60-year-old female complained of 1-week high-intensity right hemifacial pain. She had history of STN and a right trigeminal schwannoma. Subtotal tumor resection through retrosigmoid and pterional approaches, radiosurgery and two percutaneous radiofrequency ablations were performed without pain improvement 16 and 3 years ago, respectively.

Initial Numeric Rating Scale (NRS) was 10, and Barrow Neurological Institute (BNI) Pain Score was V. Neurological exam showed right hemifacial hypoesthesia, corneal reflex abolition, and temporal muscle hypotrophy. MRI revealed residual right trigeminal schwannoma at Meckel's cave ([Fig. A]).

Because of residual tumor and refractory STN, surgical resection through a right PIPA approach with TSTR was indicated. After craniotomy, the superior neurovascular complex was exposed ([Fig. B]). Suprameatal tubercle was drilled, and PIPA was completed achieving exposure and resection of tumor remnant at Meckel's cave ([Fig. C]). Cisternal segment of trigeminal nerve was pale and thin. After identification of pars minor and pars major a TSTR was performed ([Fig. D]). Postoperative and one month follow-up showed pain improvement with NRS 3 and BNI score II. Postoperative CT showed petrous apex drilled and Meckel's Cave tumor resection ([Fig. A]).

Discussion: PIPA is performed through a retrosigmoid intradural suprameatal approach and exposes Meckel's cave. Tatagiba et al published a 29 patients’ cohort with petroclival meningioma who underwent PIPA approach, achieving total resection in 66% of patients. Surgical complications included facial palsy, CSF leak, bleeding in the surgical cavity, and pneumocephalus. The trigeminal nerve and Meckel's cave are exposed with this approach; therefore, a TSTR also could be done to treat refractory STN.

Partial sensory rhizotomy (PSR) is a surgical option to treat trigeminal neuralgia and provides 70% pain relief for a 10-year duration. Outcomes depend on location of the nerve section^. Ventrolateral two-thirds of section of the pars major is the most recommended. PSR is indicated in the absence of vascular compression, inoperable vascular anatomy, or after microvascular decompression without improvement. However, we decided to do a TSTR because of the severe clinical sequels of trigeminal damage that patient presented, risk of recurrence after PSR, and better outcomes that could be obtained if more of the trigeminal sensory root is divided.

Conclusion: PIPA achieve a good exposure of cisternal portion of trigeminal nerve and Meckel's Cave. This approach allows resection of cerebellopontine angle tumors with extension to fossa media. Moreover, advanced procedures to treat refractory STN like TSTR could be done through this approach with good results.

Fig. A. (1). Preoperative MRI and (2) postoperative CT.

Fig. B. Exposure of superior neurovascular complex.

Fig. C. Residual schwannoma in Meckel's cave after PIPA.

Fig. D. Sectioned trigeminal nerve.

Publication History

Article published online:
01 February 2023