Surgery For Trigeminal Neuralgia Research Articles

Neuro-ophthalmic considerations in trigeminal neuralgia and its surgical treatment

In this review, we will briefly discuss the clinical manifestations and etiology of trigeminal neuralgia, outline the neuro-ophthalmic features of trigeminal neuralgia, and detail the neuro-ophthalmic side effects and complications of the surgical treatment of trigeminal neuralgia. There is a variety of surgical treatment modalities available for patients with trigeminal neuralgia intolerable or resistant to medical therapy. Significant ocular and visual morbidity can result from the surgical treatment of trigeminal neuralgia. Percutaneous or open surgical procedures for trigeminal neuralgia can result in corneal anesthesia, neurotrophic keratitis, exposure keratitis, herpetic keratitis, ocular motor cranial neuropathies, and optic neuropathy. Ophthalmologists should be aware of these potential problems because they may need to evaluate and provide care to patients with ocular or visual complaints following surgery for trigeminal neuralgia.

Patient satisfaction after surgery for trigeminal neuralgia – development of a questionnaire

This project aimed to prepare a self complete patient satisfaction survey for patients who have undergone surgery for trigeminal neuralgia and then assess its reproducibility, validity and acceptability in one centre. The questionnaire, for initial use in patients who had undergone posterior fossa surgery for trigeminal neuralgia, was designed after a systematic review of the surgical literature had been performed and discussions held at the US and UK Trigeminal Neuralgia Support group meetings. It underwent several changes after input from neurosurgeons, patients, copywriter and statistician and finally contained 44 questions, the SF12, Hospital Anxiety and Depression Scale (HAD), Brief Pain Inventory (BPI) and McGill Pain questionnaire (MPQ). From the total number of 413 patients in the database of one centre the questionnaire was sent with a covering letter to 305 patients, the rest had died (25), were lost to follow up (26) or did not meet the inclusion criteria (56). One patient had bilateral PSR. The completed questionnaires were evaluated by an independent physician, neurosurgeon and patient. A repeat questionnaire was sent to 10% of the patients to check reproducibility. The questionnaires were well completed with a final response rate of 92%. It appeared to be highly acceptable and reproducible but needed adjustment to improve its validity before being used in other centres and for all surgical procedures. A new questionnaire is proposed which could be used on an annual basis. A questionnaire has been developed for use in patients who have undergone surgical management for trigeminal neuralgia and which is acceptable to patients.

Patient Reports of Satisfaction after Microvascular Decompression and Partial Sensory Rhizotomy for Trigeminal Neuralgia

There are no reports of patient satisfaction surveys after either a microvascular decompression (MVD) or a partial sensory rhizotomy (PSR) for trigeminal neuralgia. This study compares patient satisfaction after these two types of posterior fossa surgery for trigeminal neuralgia, because it is postulated that recurrences, complications, and previous surgical experience reduce satisfaction. All patients who had undergone their first posterior fossa surgery at one center were sent a self-complete questionnaire by an independent physician. Among the 44 questions on four standardized questionnaires were 5 questions that related to patient satisfaction and experience of obtaining care. Patients were divided into those having their first surgical procedure (primary) and those who had had previous ablative surgery (nonprimary). Response rates were 90% (220 of 245) of MVD and 88% (53 of 60) of PSR patients. Groups were comparable with respect to age, sex, duration of symptoms, mean duration of follow-up, and recurrence rates. Overall satisfaction with their current situation was 89% in MVD and 72% in PSR patients. Unsatisfied with the outcome were 4% of MVD and 20% of PSR patients, and this is a significant difference (P < 0.01). Satisfaction with outcome was higher in those undergoing this as a primary procedure. In the primary group, satisfaction was dependent on recurrence and complication/side effects status (each P < 0.01), but this was not the case in the nonprimary group. Patients expressed a desire for earlier posterior fossa surgery in 73% of MVD and 58% of PSR patients, and this was highest in the primary group. The final outcome was considered to be better than expected in 80% of MVD and 54% of PSR patients, but 22% of the PSR group (P < 0.01) thought they were worse off. Patients undergoing posterior fossa surgery as a primary procedure are most satisfied and PSR patients are least satisfied, partly because of a higher rate of side effects.

Stereotactic gamma knife surgery for trigeminal neuralgia: detailed analysis of treatment response

The purpose of this study was to assess the durability and completeness of pain relief in patients treated using stereotactic gamma knife surgery (GKS) for trigeminal neuralgia (TN). Thirty-eight patients with refractory TN were treated with stereotactic GKS. All patients received a prescription radiation dose of 35, 40, or 45 Gy to the 50% isodose surface through a 4-mm collimator helmet. The group was assessed regularly based on physician-directed interviews for a median follow up of 24 months (range 6-27 months). Pain relief was classified as excellent (no pain without medication), good (well-controlled pain with continued medication), fair (decreased but residual pain with continued medication), or poor (unimproved or increased pain with the same or increased medication). Three months after treatment, pain relief was good or excellent in 71% of patients. By 24 months post-GKS, 50% of the original cohort had poor pain relief, 21% continued to have either excellent or good relief, 3% had fair relief, and 26% had not reached the 24-month follow up. Based on their status at the last follow up, 29% of patients had excellent and 16% had good pain relief. Thirty-seven percent experienced facial numbness, which was dose related. In addition, there was a significantly higher rate of complete pain relief in patients who had facial numbness following treatment (p = 0.003). Stereotactic GKS is an effective treatment in patients with TN; however, the durability of pain relief and the time to treatment response are limiting factors. As with other types of ablative treatment, facial numbness is strongly associated with better treatment response.

Gamma knife surgery for trigeminal neuralgia: outcomes and prognostic factors

Microvascular decompression (MVD) and percutaneous ablation surgery have historically been the treatments of choice for medically refractory trigeminal neuralgia (TN). Gamma knife surgery (GKS) has been used as an alternative, minimally invasive treatment in TN. In the present study, the authors evaluated the long-term results of GKS in the treatment of TN. From 1996 to 2003, 151 cases of TN were treated with GKS. In this group, radiosurgery was performed once in 136 patients, twice in 14 patients, and three times in one patient. The types of TN were as follows: 122 patients with typical TN, three with atypical TN, four with multiple sclerosis-associated TN, and seven with TN and a history of a cavernous sinus tumor. In each case, the chosen radiosurgical target was located 2 to 4 mm anterior to the entry of the trigeminal nerve into the pons. The maximal radiation doses ranged from 50 to 90 Gy. The median age of the patients was 68 years (range 22-90 years), and the median time from diagnosis to GKS was 72 months (range 1-276 months). The median follow up was 19 months (range 2-96 months). Clinical outcomes and postradiosurgical magnetic resonance (MR) imaging studies were analyzed. Univariate and multivariate analyses were performed to evaluate factors that correlated with a favorable, pain-free outcome. The mean time to relief of pain was 24 days (range 1-180 days). Forty-seven, 45, and 34% of patients were pain free without medication at the 1-, 2-, and 3-year follow ups, respectively. Ninety, 77, and 70% of patients experienced some improvement in pain at the 1-, 2-, and 3-year follow ups, respectively. Thirty-three (27%) of 122 patients with initial improvement subsequently experienced pain recurrence a median of 12 months (range 2-34 months) post-GKS. Among those whose symptoms recurred, 14 patients underwent additional GKS, six MVD, four glycerol injection, and one patient a percutaneous radiofrequency rhizotomy. Twelve patients (9%) suffered the onset of new facial numbness post-GKS. Changes on MR images post-GKS were noted in nine patients (7%). On univariate analysis, right-sided neuralgia (p = 0.0002) and a previous neurectomy (p = 0.04) correlated with a pain-free outcome; on multivariate analysis, both rightsided neuralgia (p = 0.032) and patient age (p = 0.05) were statistically significant. New onset of facial numbness following GKS correlated with undergoing more than one GKS (p = 0.002). At the last follow up, GKS effected pain relief in 44% of patients. Some degree of pain improvement at 3 years post-GKS was noted in 70% of patients with TN. Although less effective than MVD, GKS remains a reasonable treatment option for those unwilling or unable to undergo more invasive surgical approaches and offers a low risk of side effects.

Microvascular decompression after gamma knife surgery for trigeminal neuralgia: intraoperative findings and treatment outcomes

The authors sought to determine whether the results of trigeminal microvascular decompression (MVD) are influenced by prior gamma knife surgery (GKS). Gamma knife surgery is an established procedure for treating medically intractable trigeminal neuralgia but failures do occur. The authors assessed six patients (two men and four women; mean age 52 years) who experienced pain recurrence after GKS and elected to undergo trigeminal MVD via retrosigmoid craniotomy. Three patients underwent a single GKS to a maximal dose of 80 Gy, whereas three others underwent a second GKS to total of 120 to 135 Gy. At surgery, none of the six patients demonstrated excess arachnoid thickening, grossly apparent changes in the nerve itself, or any other tissue alterations that made successful mobilization of a blood vessel from the trigeminal root entry zone technically more difficult. A single individual had a small atherosclerotic plaque in the superior cerebellar artery near its contact point with the trigeminal nerve. Follow up at a mean of 25.4 months (range 7.5-42 months) indicated that five patients were pain free. One patient had improved but still relied on medications for pain control. In the authors' experience, trigeminal MVD can be performed without added difficulty in patients who have previously undergone GKS. The success rates seem similar to those normally associated with MVD. Patients who elect the less invasive option of GKS can be assured that trigeminal MVD remains a viable alternative at a later date if further surgery is required.

Gamma knife surgery for trigeminal neuralgia: improved initial response with two isocenters and increasing dose

Object. The authors sought to evaluate the initial response of trigeminal neuralgia (TN) to gamma knife surgery (GKS) based on the number of shots delivered and radiation dose. Methods. Between September 1998 and September 2003, some 63 patients with TN refractory to medical or surgical management underwent GKS at Upstate Medical University. Ten patients had multiple sclerosis and 25 patients had undergone prior invasive treatment. Gamma knife surgery was delivered to the trigeminal nerve root entry zone in one shot in 27 patients or two shots in 36 patients. The radiation dose was escalated to less than or equal to 80 Gy in 20 patients, 85 Gy in 21 patients, and greater than or equal to 90 Gy in 22 patients. Pain before and after GKS was assessed using the Barrow Neurological Institute Pain Scale and the improvement score was analyzed as a function of dose grouping and number of shots. Sixty patients were available for evaluation, with an initial overall and complete response rate of 90% and 27%, respectively. There was a greater improvement score for patients who were treated with two shots compared with one shot, mean 2.83 compared with 1.72 (p &lt; 0.001). There was an increased improvement in score at each dose escalation level: less than or equal to 80 Gy (p = 0.017), 85 Gy (p &lt; 0.001), and greater than or equal to 90 Gy (p &lt; 0.001). Linear regression analysis also indicated that there was a greater response with an increased dose (p = 0.021). Patients treated with two shots were more likely to receive a higher dose (p &lt; 0.001). There were no severe complications. Five patients developed mild facial numbness. Conclusions. Gamma knife surgery is an effective therapy for TN. Initial response rates appear to correlate with the number of shots and dose.

Microvascular decompression after gamma knife surgery for trigeminal neuralgia: intraoperative findings and treatment outcomes

Object. The authors sought to determine whether the results of trigeminal microvascular decompression (MVD) are influenced by prior gamma knife surgery (GKS). Methods. Gamma knife surgery is an established procedure for treating medically intractable trigeminal neuralgia but failures do occur. The authors assessed six patients (two men and four women; mean age 52 years) who experienced pain recurrence after GKS and elected to undergo trigeminal MVD via retrosigmoid craniotomy. Three patients underwent a single GKS to a maximal dose of 80 Gy, whereas three others underwent a second GKS to total of 120 to 135 Gy. At surgery, none of the six patients demonstrated excess arachnoid thickening, grossly apparent changes in the nerve itself, or any other tissue alterations that made successful mobilization of a blood vessel from the trigeminal root entry zone technically more difficult. A single individual had a small atherosclerotic plaque in the superior cerebellar artery near its contact point with the trigeminal nerve. Follow up at a mean of 25.4 months (range 7.5–42 months) indicated that five patients were pain free. One patient had improved but still relied on medications for pain control. Conclusions. In the authors' experience, trigeminal MVD can be performed without added difficulty in patients who have previously undergone GKS. The success rates seem similar to those normally associated with MVD. Patients who elect the less invasive option of GKS can be assured that trigeminal MVD remains a viable alternative at a later date if further surgery is required.

Gamma knife surgery for trigeminal neuralgia: improved initial response with two isocenters and increasing dose

The authors sought to evaluate the initial response of trigeminal neuralgia (TN) to gamma knife surgery (GKS) based on the number of shots delivered and radiation dose. Between September 1998 and September 2003, some 63 patients with TN refractory to medical or surgical management underwent GKS at Upstate Medical University. Ten patients had multiple sclerosis and 25 patients had undergone prior invasive treatment. Gamma knife surgery was delivered to the trigeminal nerve root entry zone in one shot in 27 patients or two shots in 36 patients. The radiation dose was escalated to less than or equal to 80 Gy in 20 patients, 85 Gy in 21 patients, and greater than or equal to 90 Gy in 22 patients. Pain before and after GKS was assessed using the Barrow Neurological Institute Pain Scale and the improvement score was analyzed as a function of dose grouping and number of shots. Sixty patients were available for evaluation, with an initial overall and complete response rate of 90% and 27%, respectively. There was a greater improvement score for patients who were treated with two shots compared with one shot, mean 2.83 compared with 1.72 (p < 0.001). There was an increased improvement in score at each dose escalation level: less than or equal to 80 Gy (p = 0.017), 85 Gy (p < 0.001), and greater than or equal to 90 Gy (p < 0.001). Linear regression analysis also indicated that there was a greater response with an increased dose (p = 0.021). Patients treated with two shots were more likely to receive a higher dose (p < 0.001). There were no severe complications. Five patients developed mild facial numbness. Gamma knife surgery is an effective therapy for TN. Initial response rates appear to correlate with the number of shots and dose.

Gamma knife surgery for trigeminal neuralgia: Outcome, imaging, and brainstem correlates

Purpose To review our results with gamma knife surgery (GKS) in the treatment of trigeminal neuralgia (TN), and to determine whether pain relief, medication usage, and the development of facial numbness are affected by trigeminal nerve compression, MRI imaging quality, or brainstem radiation dose. Methods and materials One hundred twelve patients with TN refractory to medical or surgical management were treated at the University of Maryland Gamma Knife Center between June 1996 and July 2001. Patients were treated using a 4-mm shot to the trigeminal nerve, at a point 2–4 mm anterior to the root entry zone of the nerve into the pons. The median dose prescribed was 75 Gy (range, 60–80 Gy). T1- and T2-weighted, axial, 1.5-mm-thick MRI images were obtained using three-dimensional gradient echo acquisition after contrast injection for treatment planning. MRI images were evaluated for imaging quality (i.e., the adequacy of visualization of the affected prepontine trigeminal nerve), the presence of trigeminal nerve compression, and the brainstem dose. Follow-up data were obtained via telephone interviews, and patients were asked to rate their pre-GKS and post-GKS pain using the Barrow Neurological Institute (BNI) Pain Intensity Scale. Patients were also asked about side effects from GKS and were asked to rate any facial numbness on the BNI Facial Numbness Scale. Medication use, time to pain response, and duration of relief were also evaluated. Results Ninety-six patients who had follow-up data were included in the analysis. Eighty-six patients (89.6%) responded to GKS with an improvement in BNI pain class. Ten patients (10.4%) were found to have an MRI of poor quality, 30 (31.3%) fair quality, and 56 (58.3%) good quality. Forty-two (43.8%) received 10% of the maximal dose to the brainstem edge, whereas 54 (56.2%) received 20%. Eleven (11.5%) patients were found to have obvious nerve compression by MRI. Imaging quality ( p = 0.1863), presence of compression ( p = 0.1147), and brainstem dose ( p = 0.3168) did not correlate with treatment response. There was also no correlation between these variables (MRI quality, compression, and brainstem dose) and medication use ( p = 0.5372, p = 0.0913, p = 0.6832, respectively). Facial numbness was the only side effect experienced. Thirteen patients reported varying degrees of facial numbness, but there was no correlation between imaging quality ( p = 0.0600), brainstem dose ( p = 0.6773), and presence of compression ( p = 0.5785) with the development of facial numbness. Conclusions Gamma knife surgery is effective in the treatment of TN and has a favorable side effect profile. Treatment response and the development of facial numbness do not correlate with MRI imaging quality, presence of nerve compression, or radiation dose to the brainstem.

Other: Patients with trigeminal neuralgia report poor satisfaction after a partial sensory rhizotomy compared to microvascular decompression

The aim was to patients satisfaction after two types of posterior fossa surgery for trigeminal neuralgia. A partial sensory rhizotomy (PSR) is performed if no convincing compression of the trigeminal nerve is found. This leads to pain relief however sensory loss occurs. A systematic review of the literature has shown no reports of patients satisfaction surveys after either a microvascular decompression (MVD) or PSR. All patients who had undergone posterior fossa surgery at one centre were sent a patient designed questionnaire by an independent physician. Among the 44 questions and 4 standardised questionnaires where 5 that related to patient satisfaction and experience of obtaining care. There was a response rate of 90% (220/245) from the MVD and 88% (53/60) from the PSR treated group. The two groups were comparable in respect of age, gender, duration of symptoms and mean duration of follow up–5 years. The MVD group had seen a mean of 5 health care professionals the PSR group has seen 4. Of those who underwent an MVD 73% felt the operation should have been done earlier whereas it was 58% for the PSR group. Satisfaction with their current situation was reported by 89% of the MVD and 72% of the PSR patients however 20% of the PSR as compared to 4% (p <0.01) of the MVD group reported being unsatisfied. The operation proved to be better than expected for 80% and 54% of patients who had an MVD or PSR respectively but 22% of the PSR group (p <0.01) thought they were worse off. If another operation was needed 76% of MVD and 56% of the PSR patients would undergo the same procedure. The PSR group are less satisfied with their outcomes probably due to increased complications. The aim was to patients satisfaction after two types of posterior fossa surgery for trigeminal neuralgia. A partial sensory rhizotomy (PSR) is performed if no convincing compression of the trigeminal nerve is found. This leads to pain relief however sensory loss occurs. A systematic review of the literature has shown no reports of patients satisfaction surveys after either a microvascular decompression (MVD) or PSR. All patients who had undergone posterior fossa surgery at one centre were sent a patient designed questionnaire by an independent physician. Among the 44 questions and 4 standardised questionnaires where 5 that related to patient satisfaction and experience of obtaining care. There was a response rate of 90% (220/245) from the MVD and 88% (53/60) from the PSR treated group. The two groups were comparable in respect of age, gender, duration of symptoms and mean duration of follow up–5 years. The MVD group had seen a mean of 5 health care professionals the PSR group has seen 4. Of those who underwent an MVD 73% felt the operation should have been done earlier whereas it was 58% for the PSR group. Satisfaction with their current situation was reported by 89% of the MVD and 72% of the PSR patients however 20% of the PSR as compared to 4% (p <0.01) of the MVD group reported being unsatisfied. The operation proved to be better than expected for 80% and 54% of patients who had an MVD or PSR respectively but 22% of the PSR group (p <0.01) thought they were worse off. If another operation was needed 76% of MVD and 56% of the PSR patients would undergo the same procedure. The PSR group are less satisfied with their outcomes probably due to increased complications.

Intraoperative mapping of the trigeminal nerve root during MVD

A method for intraoperative electrophysiological mapping of the intracranial root of the trigeminal nerve was studied in 10 patients with trigeminal neuralgia. During surgery, the trigeminal nerve root was stimulated centrally with a bipolar electrode, and antidromic responses were recorded peripherally from three branches of the trigeminal nerve in the face. In all patients, the fibers of the individual subdivisions of the trigeminal nerve root were successfully localized based on the peripheral sites of antidromic response. This neural mapping was used during microvascular decompression on nine patients and during a rhizotomy procedure on one patient. As a result of mapping, the fibers of the trigeminal division subserving the pain were clearly confirmed to be compressed by the artery in all nine patients who were undergoing microvascular decompression. Likewise, the antidromic responses precisely identified the first division of the trigeminal nerve, which should be preserved to avoid postoperative corneal ulcer in the patient undergoing rhizotomy. Based on this experience, it was concluded that this technique enables surgeons to precisely identify which fibers of the trigeminal nerve root should be decompressed or divided during surgery for trigeminal neuralgia.

Predictive model for pain recurrence after posterior fossa surgery for trigeminal neuralgia.

Surgical exploration of the posterior fossa is the definitive treatment for trigeminal neuralgia refractory to medication, but predictors of its success in effecting long-term pain relief have not been established. To develop a model that allows stratification of patients' risk of postoperative recurrence of pain based on pretreatment factors. We reviewed the records of 420 consecutive patients who underwent posterior fossa exploration by one of us (C.B.W.) for the treatment of idiopathic trigeminal neuralgia. The primary outcome measure was recurrence of trigeminal pain. The predictive value of preoperative and intraoperative factors was evaluated. Multivariate analysis revealed the statistically significant predictors of pain recurrence, permitting creation of a risk model for recurrence of pain. After surgery, trigeminal pain had lessened in 98% of patients and completely resolved in 87%. There were no perioperative deaths. After a mean follow-up of 56.3 months, 93% of patients reported significant pain improvement and 72% continued to have no pain. The estimated likelihood of pain recurrence at 8 years was 34%. Significant predictors of eventual recurrence of pain were age younger than 53 years at the time of surgery, symptoms lasting longer than 11(1/2) years, female sex, and pain on the left side in men. These factors were weighted and incorporated into a risk model that revealed 4-year pain-free survival of 89% +/- 4% for the low-risk group, 80% +/- 4% for the moderate-risk group, and 58% +/- 6% for the high-risk group (data are mean +/- SD). We developed a predictive model that stratifies the risk for eventual recurrence of pain after posterior fossa exploration for trigeminal neuralgia. This information may be useful in counseling patients regarding treatment.

Endoscopy as a tool in minimally invasive trigeminal neuralgia surgery.

The aim of this study was assessment of the use of endoscopy in minimally invasive surgery of the cerebellopontine angle in cases of trigeminal neuralgia. This study comprises 42 cases of trigeminal neuralgia that underwent operation with endoscopic-assisted microvascular decompression between October 1992 and October 1998. This study was performed in the Ear, Nose, and Throat Department, Nord Hospital, in Marseille, France. The decompression was performed by means of a minimally invasive retrosigmoid approach without a cerebellar retractor. The cerebellopontine angle was then explored by a 30-degree endoscope that gives a panoramic view of this space, with clear visualization of the trigeminal nerve from the pons to Meckel's cave, allowing for the identification of the precise location of the site of the conflict. Microvascular decompression was performed under the microscope by separating the offending vessel from the trigeminal nerve; separation was maintained by the insertion of a piece of Teflon. The site of conflict was detected at the root entry zone of the nerve in 35 patients (83.3%) and at Meckel's cave in 7 patients (16.7%). In 32 cases (76.2%), the type of contact between the vessel and the nerve was of the simple type (1 vessel coming in contact with the nerve in a single point); in 6 cases (14.3%), it was a multiple type (2 vessels touching the nerve in the same point); and in 4 cases (9.5%), it was a nutcracker type (2 vessels compressing the nerve between them). After at least 1-year follow-up and a single operation (cases that required a second operation for revision were considered failures), a successful result was obtained in 31 cases (73.8%), and an improvement was obtained in 4 cases (9.5%). The operation was a failure or early recurrence occurred in 7 cases (16.7%). Postoperative complications were rare. A cerebrospinal fluid leak occurred in only 1 case (2.4%) and was subsequently treated with lumbar puncture and a compressive bandage. The minimally invasive retrosigmoid endoscopic-assisted microvascular decompression is an acceptable treatment of primary trigeminal neuralgia. Endoscopy provides a unique way to explore the cerebellopontine angle and to identify the exact location of the neurovascular conflict.

Treatment of idiopathic trigeminal neuralgia: comparison of long-term outcome after radiofrequency rhizotomy and microvascular decompression. (Heidelberg College of Medicine, Heidelberg, Germany) Neurosurgery. 2001;48:1261-1267.

The purpose of this study was to evaluate the long-term outcome of patients after either percutaneous trigeminal rhizotomy or microvascular decompression (MVD) for idiopathic trigeminal neuralgia at a single institution. Overall, the results of the study showed that there was a 50% risk of recurrence of pain 2 years after percutaneous radiofrequency rhizotomy. Conversely, 64% of the patients who underwent MVD remained completely pain free 20 years postoperatively. Patients without sensory impairment after MVD were pain free significantly longer than patients who experienced postoperatively hypesthesia or partial rhizotomy. Conclude that because it is curative and nondestructive, MVD is considered the treatment of choice for trigeminal neuralgia in otherwise healthy people. In this study, it was proved to be a more effective and long-lasting procedure for patients with typical trigeminal neuralgia than radiofrequency rhizotomy. Patients without postoperative sensory deficit remained pain free significantly longer, which is a strong argument against the “trauma” hypothesis of this procedure. Comment by Ron Pawl, M.D. This paper is noteworthy in that comparing the follow-up on 225 of 378 patients who underwent microvascular decompression (MVD) with 206 of 316 who underwent radiofrequency thermocoagulation (RFT), the RFT group stood a 50% risk of recurrent pain by 2 years after the procedure, whereas 64% of those undergoing MVD were pain-free after 20 years. Furthermore, after MVD, those patients with no postoperative sensory deficit, measured with von Frey hairs, remained pain-free longer than those with a sensory deficit. This latter finding flies in the face of the concept that to be effective, surgery for trigeminal neuralgia must damage the nerve. The whole concept of RF lesioning of the nerve is to damage it enough to deaden the trigger zone of the affected nerve branch. However, in this study it is noted that postoperative hypesthesia was only temporary after RF lesioning, which might well explain the high rate of pain recurrence in this series. Although the long-term pain relief in the MVD group is excellent, it must be weighed against the complications. In the MVD group, there were 3 mortalities, diminished hearing in 5%, loss of hearing in 2.6%, facial paralysis in 4 patients, and tinnitus in 4 patients, none of which occurred in the RF group.

Imaging the trigeminal nerve and pons before and after surgical intervention for trigeminal neuralgia.

To study the various imaging changes occurring in the trigeminal nerve and brainstem in patients before or after trigeminal neuralgia surgery. During a 7-year period, 275 patients with trigeminal neuralgia underwent high-resolution, contrast-enhanced magnetic resonance imaging (MRI) of the pons during gamma knife radiosurgery. Ninety-seven patients had no previous surgical intervention for trigeminal neuralgia, and 178 patients had undergone one or more previous procedures. Two independent observers, one of whom was blinded to patients' clinical details, reviewed MRI scans retrospectively. The analysis of the independent observers was then correlated with all previous therapeutic interventions. One hundred one MRI scans demonstrated no radiological changes related to trigeminal neuralgia, and 174 MRI scans exhibited some radiological abnormality. The average axial plane diameter of the nerve for all patients was 4 mm (range, 2-6 mm). In the group that had not undergone previous surgery, 65 patients (67%) exhibited vascular compression. In the 88 patients who had undergone previous microvascular decompression, 21 (24%) had evidence of a pontine infarction. Twenty-six patients experienced facial sensory loss, 22 (88%) of whom had undergone previous surgery with evidence of a pontine infarction (n = 11) or perineural scarring (n = 6). The majority of patients who had undergone previous trigeminal neuralgia surgery demonstrated readily identifiable abnormalities of the trigeminal nerve or brainstem. The frequency of such changes correlated with the type and number of procedures. Evidence of vascular compression was detected in the majority of patients. Most patients with postoperative facial sensory loss demonstrate changes in the nerve or pons on MR images.

Gamma Knife Radiosurgery as the First Surgery for Trigeminal Neuralgia

To evaluate the role of Gamma Knife radiosurgery as the first surgical therapy in the management of medically refractory trigeminal neuralgia, we reviewed outcomes on our first 23 patients who had radiosurgery as primary surgical therapy. These patients represented 19% of our overall series. Mean patient age was 66 years, and mean follow-up after radiosurgery was 12 months (range 5–33 months). For most patients, radiosurgery was performed because the patient had medical contraindications to open surgery. 14 patients had 70-Gy radiosurgery, and 9 patients, 80 Gy. Radiosurgery was performed using a single 4 mm isocenter. Postoperative imaging 6 to 9 months following radiosurgery confirmed regions of enhancement at the radiosurgical target. Nine patients received 70 Gy, and 8 patients had 80 Gy. 17 patients (74%) had an excellent result (total pain relief). Five patients (22%) achieved a good result (50–90% improvement). One patient had a poor result (4%) after 70-Gy radiosurgery and subsequently underwent microvascular decompression. No patient developed facial numbness or any other complication after Gamma Knife radiosurgery. Gamma Knife radiosurgery using 70 or 80 Gy targeted to the proximal trigeminal nerve proved to be a safe and effective primary surgical therapy for medically refractory trigeminal neuralgia. The overall response rate (96%) was similar to that obtained with other surgical therapies performed as a first procedure.

Neurophysiologic assessment of trigeminal function after surgery for trigeminal neuralgia

To assess the function of the three trigeminal divisions, we studied corneal reflex, early and late blink reflexes, early and late masseter silent periods, and jaw jerk in normal subjects and in 35 patients submitted to surgery for trigeminal neuralgia. The corneal reflex was most sensitive to thermocoagulation and the jaw jerk to microcompression; the other reflexes showed an intermediate behavior, depending on afferent fiber size. Trigeminal function was less impaired after microcompression and recovered earlier than after thermocoagulation.

Evoked taste thresholds in a normal population and the application of electrogustometry to trigeminal nerve disease.

No standardised method for taste threshold measurement is available and therefore comparison between clinical studies is difficult. An electrogustometer was evaluated in normal subjects. No sex difference in taste threshold was noted; however, there was a significant elevation in detection threshold with age and smoking. Electrogustometric values both in patients before and after surgery for trigeminal neuralgia and in patients with trigeminal sensory neuropathy were determined. Many patients with trigeminal nerve disorders had abnormal electrogustometric detection thresholds suggesting that there is possibly an accessory taste pathway through the trigeminal nerve, although in some individuals the site of lesion may be in the brain stem. Electrogustometry is a convenient method for clinically assessing taste.

Giant Ulcer of the Face Following Surgery for Trigeminal Neuralgia

TRIGEMINAL neuralgia (tic douloureux) is one of the commoner forms of neuralgia and one which frequently necessitates surgical treatment. Many patients develop complications following surgery. The most common complication is herpes simplex, a significant number of patients develop neuroparalytic keratitis, and a rare patient develops neurotrophic ulceration of the face, a complication which is not well known and, therefore, is frequently misdiagnosed and consequently mismanaged. This paper is a report of a patient who developed a giant ulcer of the side of the face following surgical ablation of the homolateral trigeminal nerve. Report of Case An 83-year-old white woman was first admitted to the Barnard Free Skin and Cancer Hospital in July 1965 with a giant ulcer of the right cheek. The ulcer began eight months before on the right side of the upper lip immediately above the angle of the mouth. A clinical diagnosis of keratoses of the