Long-term efficacy and safety of internal neurolysis for trigeminal neuralgia without neurovascular compression

Abstract

T rigeminal neuralgia (TN) is a pain syndrome characterized by severe, paroxysmal, lancinating facial pain. While many patients experience relief with carbamazepine or other drugs, many patients require surgery when their symptoms become refractory to medical therapy, or when they can no longer tolerate the medications.1 Surgical treatments such as neurectomy have targeted peripheral branches of the nerve external to the skull, and percutaneous ablative therapies have been directed at the gasserian ganglion using techniques such as radiofreabbreviatioNs BAEP = brainstem auditory evoked potential; BNI = Barrow Neurological Institute; BPI = Brief Pain Inventory; GKS = Gamma Knife surgery; HR = hazard ratio; IN = internal neurolysis; MVD = microvascular decompression; NVC = neurovascular compression; PSR = partial sensory rhizotomy; QOL = quality of life; REZ = root entry zone; RFL = radiofrequency gangliolysis; TN = trigeminal neuralgia. . Chart reviews and telephone interviews were conducted to assess patient outcomes. Pain intensity was evaluated with the Barrow Neurological Institute (BNI) Pain Intensity scale, and the Brief Pain Inventory-Facial (BPIFacial) was used to assess general and face-specific activity. Pain-free survival and durability of successful pain relief (BNI pain scores of 1 or 2) were statistically evaluated with Kaplan-Meier analysis. Prognostic factors were identified and analyzed using Cox proportional hazards regression. results A total of 177 patients with Type 1 TN were identified. A subgroup of 27 was found to have no NVC on highresolution MRI/MR angiography or at surgery. These patients were significantly younger than patients with classic Type 1 TN. Long-term follow-up was available for 26 of 27 patients, and 23 responded to the telephone survey. The median follow-up duration was 43.4 months. Immediate postoperative results were comparable to MVD, with 85% of patients pain free and 96% of patients with successful pain relief. At 1 year and 5 years, the rate of pain-free survival was 58% and 47%, respectively. Successful pain relief at those intervals was maintained in 77% and 72% of patients. Almost all patients experienced some degree of numbness or hypesthesia (96%), but in patients with successful pain relief, this numbness did not significantly impact their quality of life. There was 1 patient with a CSF leak and 1 patient with anesthesia dolorosa. Previous treatment for TN was identified as a poor prognostic factor for successful outcome. coNclusioNs This is the first report of IN with meaningful outcomes data. This study demonstrated that IN is a safe, effective, and durable treatment for TN in the absence of NVC. Pain-free outcomes with IN appeared to be more durable than radiofrequency gangliolysis, and IN appears to be more effective than stereotactic radiosurgery, 2 alternatives to posterior fossa exploration in cases of TN without NVC. Given the younger age distribution of patients in this group, consideration should be given to performing IN as an initial treatment. Accru...

Outcome of Internal Neurolysis for Trigeminal Neuralgia without Neurovascular Compression and Its Relationship with Intraoperative Trigeminocardiac Reflex

“…Different from another ablative procedure, namely PSR, IN is performed longitudinally along nerve fibers without cutoff; thus, sensory dysfunction should be minor [2]. In our study, the results of follow-up indicate that IN is an effective treatment for TN without NVC, which is in accordance with previous publications [1, 3, 4]. However, there have been neither studies clearly illuminating the mechanism of IN, nor studies exploring prognostic factors for outcomes of IN.…”

“…As a result, the extent of nerve injury with IN is much less than with partial sensory rhizotomy (PSR) [2] but more than with MVD. In recent case reports of IN, the efficacy of IN was 72–93%, and the rate of numbness or hypesthesia was 60–96% [1, 3-6]. …”

Comparing Percutaneous Treatments of Trigeminal Neuralgia: 19 Years of Experience in a Single Centre

“…If no blood vessel is seen to be compressing the nerve, then ablative surgery (including percutaneous treatments) is an option. Patients who do not want MVD or an open alternative such as partial sensory rhizotomy or internal neurolysis [3], or have a high surgical/anaesthetic risk due to multiple comorbidities or age, are considered for percutaneous surgical treatment. Percutaneous procedures include rhizolysis procedures as well as less invasive procedures (including peripheral nerve avulsions, cryolesions, and alcohol ablations), but the latter are often temporary solutions giving only a few months' pain relief.…”

Trigeminal neuralgia without neurovascular compression presents earlier than trigeminal neuralgia with neurovascular compression

“…Long-term results for IN have recently been studied, and findings suggest that success with this treatment strategy for patients without NVC may be more durable than other ablative procedures. 18 This may be particularly relevant for younger patients, as ablative procedures are less durable than MVD and IN. For example, median time to pain recurrence for percutaneous radiofrequency trigeminal gangliolysis is on the order of 3 years, 5 while median time to treatment failure was not reached after 5 years for IN.…”

“…For example, median time to pain recurrence for percutaneous radiofrequency trigeminal gangliolysis is on the order of 3 years, 5 while median time to treatment failure was not reached after 5 years for IN. 18 A structured, well-designed comparison of the efficacy and durability of different techniques for treating TN without NVC is warranted, and acquiring a sufficient cohort for a prospective trial would require a concerted, collaborative effort. The findings of this study provide a rationale for pursuing such an effort: if patients without NVC tend to be younger and likelihood of recurrence is higher, then these patients have a greater chance of being subject to repeated ablative procedures, with concomitantly increased chances of the sequelae of deafferentation.…”