Background: Microvascular decompression is considered to be a potential treatment for most trigeminal neuralgia cases with obvious neurovascular conflict. Partial sensory rhizotomy (PSR) is an alternate option in cases of negative investigation for neurovascular conflict, although its effectiveness and technical complexity are still being debated.

Objective: To evaluate the therapeutic efficacy of PSR following negative-exploration trigeminal neuralgia (NETN) in terms of pain control, adverse effects from sensory fiber destruction, and patient satisfaction in the short-term or after 1 month, and in the long-term or after 12 months. In addition, technical nuances were highlighted to mitigate the negative effects of PSR.

Materials and Methods: The present study enrolled 27 NETN patients, and all were operated by the same neurosurgeon. The patients underwent surgery via a keyhole retromastoid technique, with extensive exploration for any possible intraoperative neurovascular conflict. A modified PSR approach was used to operate on these negative exploration cases, and this entailed cutting fewer than 1/5 of the trigeminal sensory fibers. The short-term or within one month, and long-term or after one-year intervals were used to track all instances. The therapeutic efficacy of employing pain score and subjective sensation in terms of pain control, adverse consequences from sensory fiber destruction, and patient satisfaction were investigated.

Results: Eighty-five point two percent of patients reported excellent pain control following PSR, in terms of both pain score and total pain alleviation. Despite having their trigeminal nerve fibers severed, not all of the patients experienced numbness, and 45% of patients recovered to some extent on their own within a year. Only 13% of patients had Anesthesia Dolorosa in the present trial, which could be attributable because only 1/5 of the trigeminal nerve fibers were severed. There was no relationship between pain distribution and pain alleviation efficacy before and after PSR. When PSR was effective, most patients should notice an improvement within a month of the surgery.

Conclusion: For patients with negative exploration following keyhole suboccipital craniectomy, PSR proved to be therapeutic and effective in alleviating trigeminal neuralgic pain. The majority of the patients can tolerate the minor side effects from minute nerve destruction well, particularly numbness, which partially resolves on its own with time.

Keywords: Negative exploration; Trigeminal neuralgia; Microvascular decompression; Partial sensory rhizotomy; Efficacy

DOI: 10.35755/jmedassocthai.2022.09.13564

Received 13 June 2022 | Revised 30 June 2022 | Accepted 8 July 2022