Technical Assessment of Microvascular Decompression for Trigeminal Neuralgia Using a 3-Dimensional Exoscope: A Case Series.

BACKGROUND: Detailed anatomic visualization of the root entry zone of the trigeminal nerve is crucial to successfully perform microvascular decompression surgery (MVD) in patients with trigeminal neuralgia. OBJECTIVE: To determine advantages and disadvantages using a 3-dimensional (3D) exoscope for MVD surgery. METHODS: A 4K 3D exoscope (ORBEYE) was used by a single surgical team for MVD in a retrospective case series of 8 patients with trigeminal neuralgia in a tertiary center. Clinical and surgical data were collected, and advantages/disadvantages of using the exoscope for MVD were recorded after each surgery. Descriptive statistics were used to summarize the data. RESULTS: Adequate MVD of the trigeminal nerve root was possible in all patients by exclusively using the exoscope. It offered bright visualization of the cerebellopontine angle and the root entry zone of the trigeminal nerve that was comparable with a binocular operating microscope. The greatest advantages of the exoscope included good optical quality, the pronounced depth of field of the image for all observers, and its superior surgeon ergonomics. Disadvantages were revealed with overexposure at deep surgical sites and the lack of endoscope integration. In 6 patients, facial pain improved significantly after surgery (Barrow Neurological Institute pain intensity score I in 5 and III in 1 patient), whereas it did not in 2 patients (Barrow Neurological Institute score IV and V). No complications occurred. CONCLUSION: Utilization of a 3D exoscope for MVD is a safe and feasible procedure. Surgeons benefit from better ergonomics, excellent image quality, and an improved experience for observers.

Diffusion tensor imaging for assessment of microstructural changes associate with treatment outcome at one-year after radiofrequency Rhizotomy in trigeminal neuralgia.

BACKGROUND: Trigeminal neuralgia (TN) is characterized by facial pain that may be sudden, intense, and recurrent. Neurosurgical interventions, such as radiofrequency rhizotomy, can relieve TN pain, but their mechanisms and effects are unknown. The aim of the present study was to investigate the microstructural tissue changes of the trigeminal nerve (TGN) in patients with TN after they underwent radiofrequency rhizotomy. METHODS: Thirty-seven patients with TN were recruited, and diffusion tensor imaging was obtained before and two weeks after radiofrequency rhizotomy. By manually selecting the cisternal segment of the TGN, we measured the volume of the TGN, fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD). The TGN volume and mean value of the DTI metrics of the post-rhizotomy lesion side were compared with those of the normal side and those of the pre-rhizotomy lesion side, and they were correlated to the post-rhizotomy visual analogue scale (VAS) pain scores after a one-year follow-up. RESULTS: The alterations before and after rhizotomy showed a significantly increased TGN volume and FA, and a decreased ADC, AD, and RD. The post-rhizotomy lesion side showed a significantly decreased TGN volume, FA, and AD compared with the normal side; however, no significant difference in the ADC and RD were found between the groups. The TGN volume was significantly higher in the non-responders than in the responders (P = 0.016). CONCLUSION: Our results may reflect that the effects of radiofrequency rhizotomy in TN patients include axonal damage with perineural edema and that prolonged swelling associated with recurrence might be predicted by MRI images. Further studies are necessary to understand how DTI metrics can quantitatively represent the pathophysiology of TN and to examine the application of DTI in the treatment of TN.

Nationwide Shift From Percutaneous Rhizotomy to Microvascular Decompression for Treatment of Trigeminal and Other Cranial Nerve Neuralgias.

OBJECTIVE: The aim of this study was to report the trends in the use of common surgical interventions over the past decade to treat cranial nerve neuralgias. METHODS: The Centers for Medicare and Medicaid Services Part B National Summary Data File from 2000 to 2016 were studied. RESULTS: A total of 57.1 million persons were enrolled in 2016, up from 39.6 million persons in 2000. Suboccipital craniectomy done for cranial nerve decompressions (including cranial nerves V, VII, and IX) increased by 33.9 cases per year so that in 2016 the number of cases was 167% of what it was 17 years earlier (ie, from 655 cases in 2000 to 1096 cases in 2016). The less commonly used subtemporal approach craniectomy to treat trigeminal neuralgia (TN) increased by 1.13 cases per year (ie, from 25 cases in 2000 to 46 cases in 2016). The less invasive percutaneous rhizotomy procedures, including glycerol and radiofrequency ablation, for treatment of TN decreased by 42.9 cases per year (64%; ie, from 2578 cases in 2000 to 1206 cases in 2016). CONCLUSIONS: Overall trends show increased use of open surgery and decreased use of percutaneous rhizotomy, including destruction of the trigeminal nerve using balloon compression, glycerol injection, or thermal injury. These trends may be related to differences in outcomes between treatment modalities.

Percutaneous trigeminal rhizotomy in a biplane angiosuite: technical assessment.

BACKGROUND: Percutaneous trigeminal rhizotomy (PTR) uses fluoroscopic guidance to cannulate the foramen ovale for the treatment of trigeminal neuralgia. OBJECTIVE: To describe the use of a high-resolution biplane neuroangiosuite for PTR and retrospectively to assess the performance of this technique. METHODS: From 1990 through 2010, 67 PTRs were performed in 51 patients at our institution; 47 used the c-arm in the operating room (OR) and 20 used the biplane angiosuite. Hospital charts were reviewed for demographics, symptomatology, operative time, number of cannulation attempts, fluoroscopy time and pain outcome. Two-tailed univariate analyses were performed to compare the OR and angiosuite groups. RESULTS: In 20 of 67 PTRs, biplane fluoroscopic guidance in the angiosuite was used. Variations in type of PTR, fluoroscopy technique and follow-up time barred meaningful comparison of these variables between OR and biplane groups. However, the biplane group had significantly fewer mean cannulation attempts (1 vs 2.2, p<0.001). CONCLUSIONS: High-resolution biplane neuroangiosuites offer a readily available alternative to ORs for PTR in the treatment of trigeminal neuralgia. Use of the biplane fluoroscopy machine was practical, safe and at least as effective as the use of the c-arm. It may also offer the advantages of a reduced number of cannulation attempts.

Caudal compression of the infraorbital nerve: a novel surgical technique for treatment of idiopathic headshaking and assessment of its efficacy in 24 horses.

UNLABELLED: REASONS FOR DESIGNING AND REPORTING TECHNIQUE: Idiopathic headshaking has remarkable similarities to human neuropathic facial pain syndromes associated with post herpetic and trigeminal neuralgia. These derive from abnormal sensory function within the peripheral or central pathways of the trigeminal nerve (TgN). Limiting input from the TgN can be helpful in controlling the perception of pain. Rhizotomy of the infraorbital branch of the TgN as it emerges from the infraorbital canal has been reported but has a poor efficacy. A novel technique involves compression of the nerve at a more caudal location within the infraorbital canal and the technique requires validation. HYPOTHESIS: Caudal compression of the infraorbital nerve with platinum coils, performed in horses diagnosed with idiopathic headshaking, results in a decrease in clinical signs. METHODS: Caudal compression of the infraorbital nerve, using platinum embolisation coils, was performed under fluoroscopic guidance. Clinical records of 24 idiopathic headshakers that had undergone this procedure were reviewed. Follow-up information was obtained by telephone questionnaire with the owner or referring veterinary surgeon. RESULTS: All 24 horses had at least one surgical procedure. Median follow-up time was 6 months. There were 2 horses which had surgery 2 weeks before follow-up and these were excluded from the analysis of outcome. Following one surgery, 13/22 horses (59.0%) had a successful outcome. Of the 9 horses that did not improve, surgery was repeated in 6 cases. Two of these horses had a successful outcome. Overall, a successful outcome was obtained in 16/19 horses (84.2%). CONCLUSIONS: This surgical technique is likely to prevent input from the TgN at a more caudal location then the previously described infraorbital neurectomy. The technique requires refinement.

Evolution in the assessment and management of trigeminal schwannoma.

EDUCATIONAL OBJECTIVE: At the conclusion of this presentation, the participants should be able to understand the contemporary assessment and management algorithm used in the evaluation and care of patients with trigeminal schwannomas. OBJECTIVES: 1) Describe the contemporary neuroradiographic studies for the assessment of trigeminal schwannoma; 2) review the complex skull base osteology involved with these lesions; and 3) describe a contemporary management algorithm. STUDY DESIGN: Retrospective review of 23 cases. METHODS: Chart review. RESULTS: From 1984 to 2006, of 23 patients with trigeminal schwannoma (10 males and 13 females, ages 14-77 years), 15 patients underwent combined transpetrosal extirpation, 5 patients underwent stereotactic radiation, and 3 were followed without intervention. Of the 15 who underwent surgery, total tumor removal was achieved in 9 patients. Cytoreductive surgery was performed in six patients; of these, four received postoperative radiation. One patient who underwent primary radiation therapy required subsequent surgery. There were no deaths in this series. Cranial neuropathies were present in 14 patients pretreatment and observed in 17 patients posttreatment. Major complications included meningitis (1), cerebrospinal fluid leakage (2), major venous occlusion (1), and temporal lobe infarction (1). CONCLUSIONS: Trigeminal schwannomas are uncommon lesions of the skull base that may occur in the middle fossa, posterior fossa, or both. Moreover, caudal extension results in their presentation in the infratemporal fossa. Contemporary diagnostic imaging, coupled with selective use of both surgery and radiation will limit morbidity and allow for the safe and prudent management of this uncommon lesion.

A comparison of patient satisfaction and objective assessment of neurosensory function after trigeminal nerve repair.

PURPOSE: The purpose of this study was to compare objective and subjective assessments of neurosensory function after trigeminal nerve repair. METHODS: This was a retrospective cohort study using a sample of patients who underwent surgical repair of trigeminal nerve injuries. The primary study variables were categorized as objective or subjective. The objective variable was the change in neurosensory examination between preoperative and 1-year postoperative visits. Neurosensory status was measured using an ordinal scale ranging from anesthetic (0) to normal (4). Subjective variables included patient satisfaction with the nerve repair and patient assessment of injury-related oral dysfunction. Demographic, anatomic, and operative variables were also collected. Appropriate univariate and bivariate statistics were computed. RESULTS: The sample was composed of 19 patients (14 female, 17 Caucasian) who had trigeminal nerve repair (17 lingual, 2 inferior alveolar). The mean duration between injury and repair was 4.5 +/- 2.3 months; between repair and postoperative assessment was 11.9 +/- 0.9 months. The mean change in neurosensory status was 1.3 +/- 1.0 levels. The majority of patients (63.1%) rated their satisfaction with the outcome of treatment as "good" to "excellent." There was a statistically significant correlation between change in neurosensory status and patient satisfaction (rho = 0.86; P < .01). CONCLUSION: There is evidence of a strong correlation between improvement in the neurosensory examination following trigeminal nerve repair and patient satisfaction with the surgical outcome 1-year postoperatively. Patients who experience greater neurosensory improvement also report lower frequencies of related oral dysfunction.

Subjective outcomes following sural nerve harvest.

PURPOSE: The goal of this study was to assess subjective patient recovery of donor site sensory deficit following sural nerve harvest for trigeminal nerve repair surgery. PATIENTS AND METHODS: A review of 42 consecutive sural nerve graft patient records yielded 26 patients, at least 20 months following sural nerve grafting for trigeminal nerve repair, who participated in a telephone questionnaire survey to assess subjective outcomes. The association between donor site outcome and other factors, including nerve graft recovery, age, gender, pain, cold sensitivity, scar cosmesis and tactile sensitivity, and legal involvement were analyzed, and presurgical and present levels of donor and nerve graft site sensibility were compared. RESULTS: The perceived area of donor site sensory deficit decreased significantly over time. Postoperative donor site pain and cold sensitivity at low levels were reported by few patients, and the majority have completely resolved. Most patients reported no problems with scar cosmesis or pain. There was a moderate agreement between donor site recovery and nerve graft recovery (kappa = 0.32). Few patients reported satisfaction with one site and not the other or complete dissatisfaction with both sites. Other factors such as age, gender, or legal involvement were not found to correlate with satisfaction level. CONCLUSIONS: The use of a questionnaire for subjective assessment of neurosensory recovery following nerve graft repair yields outcomes information that is generally not considered in the traditional clinical patient assessment. The majority of patients tolerate sural nerve harvest without significant donor site morbidity.