Neurosurgical therapy of facial neuralgias

INTRODUCTION: Neuralgias of the face, especially trigeminal neuralgia and glossopharyngeal neuralgia are indications for surgical interventions after failed medical therapy. In contrast to other forms of headache or atypical facial pain, where surgical measures are considered to be contraindicated, percutaneous procedures or microvascular decompression are able to produce immediate and longstanding pain relief. Careful preoperative evaluation is essential to confirm the clinical diagnosis and to rule out other causes as multiple sclerosis or tumors afflicting the cranial nerves. The following study will summarize the common surgical techniques and their role considering a mechanism-based therapy as well as document long-term results of these measures. METHODS: Between 1977 and 1997 316 thermo-controlled radiofrequency trigeminal rhizotomies (TK) and 379 microvascular decompressions (MVD) were performed in our hospital to treat trigeminal neuralgia; additional 6 MVDs for glossopharyngeal neuralgia and one MVD of the intermediate facial nerve were carried out. Questionnaires were sent out to all patients still living in 1981, 1982, 1992 and 1998. For all other patients, interviews with relatives or the general practitioners were conducted. A retrospective analysis of postoperative pain relief was performed using Kaplan-Meier curves at the latest follow-up. Additionally 80 patients underwent careful quantitative sensory testing with Von-Frey-hairs. RESULTS: 225 patients who underwent microvascular decompression and 206 with radiofrequency trigeminal rhizotomies were further analyzed. There was a 50% risk for pain recurrence two years after radiofrequency rhizotomy. On the other hand 64% of patients who underwent microvascular decompression remained painfree 20 years postoperatively. Patients with microvascular decompression without sensory deficit were painfree significantly longer than patients with postoperative hypesthesia. DISCUSSION: Etiology and pathogenesis of facial neuralgias are far from understood despite several hypotheses. Based on current models there is no explanation for the immediate pain relief especially after microvascular decompression. Some authors even discuss surgical trauma as the only cause for postoperative pain relief.

The effectiveness of 100 and 200 mg etodolac (Ultradol), aspirin, and placebo in patients with pain following oral surgery.

The analgesic efficacy of etodolac (Ultradol) was evaluated in 168 patients experiencing moderate to severe pain following oral surgery. The patients were given either etodolac 100 mg, etodolac 200 mg, aspirin 650 mg, or placebo. There was a minimum of forty patients in each drug group. Patients recorded pain intensity and pain relief at 1/2 hour and then hourly for up to 12 hours after medication. The efficacy variables analyzed were the sum of pain-intensity differences, total pain relief, onset of analgesia, and the patient's opinion of the study drug. Time-effect curves were made from the pain-relief and pain-intensity difference scores. The analgesic potency of both 100 and 200 mg of etodolac was comparable to 650 mg of aspirin and superior to placebo. Like aspirin, both doses of etodolac showed significant analgesia within one hour and a significantly longer duration of action than placebo.

Gamma knife surgery with a dose of 75 to 76.8 Gray for trigeminal neuralgia.

OBJECT: The author presents a large series of patients with idiopathic trigeminal neuralgia (TN) who were treated with gamma knife surgery (GKS), at a maximum dose of 75 to 76.8 Gy, and followed up in a nearly uniform manner for up to 4.6 years. METHODS: Two hundred ninety-three patients were treated and followed up for at least 6 months (range 0.4-4.6 years, median 1.9 years). At the final follow-up review, there was complete (100%) pain relief without medicines in 64 patients (21.8%), 90% or greater relief with or without small doses of medicines in 86 (29.4%), between 75 and 89% relief in 31 (10.6%), between 50 and 74% relief in 19 (6.5%), and less than 50% relief in 23 patients (7.8%). Recurrent pain requiring a second procedure occurred in 70 patients (23.9%). Kaplan-Meier analysis showed that 100%, 90% or greater, and 50% or greater pain relief was obtained and maintained for 3.5 to 4.1 years in 5.6, 23.7, and 50.4% patients, respectively. Of 31 patients who described pain relief ranging from 75 to 89%, 80% of patients described it as good and 10% as excellent; of 17 patients who reported between 50 and 74% pain relief, 53% described it as good and none as excellent (p = 0.014). Dysesthesia scores greater than 5 (scale of 0-10, in which a score of 10 represents excruciating pain) occurred in four (3.2%) of 126 patients who had not undergone prior surgery; all these patients obtained either good or excellent relief from TN pain. There were 36 patients in whom the TN had atypical features; these patients were less likely to attain at least 50% or at least 90% pain relief compared with those without atypical TN features (p = 0.001). CONCLUSIONS: Gamma knife surgery is a safe and effective way to relieve TN. Patients who attain between 75 and 89% pain relief are much more likely to describe this outcome as good or excellent than those who attain between 50 and 74% pain relief.

Computerized tomography-guided percutaneous extralemniscal myelotomy.

Extralemniscal myelotomy (ELM) is a procedure performed at the cervicomedullary junction of the spinal cord in which the central cord is lesioned to treat intractable pain. The neurophysiological mechanism of pain relief after ELM remains unclear. The authors present a series of 14 patients with intractable cancer pain who were managed by CT-guided, percutaneous ELM. In six of the cases (42.8%), total pain relief was achieved; partial satisfactory pain relief was attained in four cases (28.5%), and no pain control was achieved in four cases (28.5%). No complications due to ELM were observed. The authors believe that ELM is a safe and effective procedure in the management of intractable cancer pain for selected cases; computerized tomography guidance is an essential part of the procedure to achieve morphological localization of the target in the cervicomedullary junction. More research is needed to understand the neurophysiological mechanism of pain relief after ELM and to standardize the lesion volume.

Variation in the placebo effect in randomised controlled trials of analgesics: all is as blind as it seems.

The objective was to investigate the relationship between pain relief scores produced by placebo and by active interventions in randomised controlled trials (RCTs). Individual patient categorical pain relief scores from 5 placebo-controlled single-dose parallel-group RCTs in acute postoperative pain were used to calculate the percentage of the maximum possible pain relief score (%maxTOTPAR) for the different treatments. One hundred and thirty of the 525 patients in the 5 trials had a placebo. Individual patients' scores with placebo varied from 0 to 100% of the maximum possible pain relief. The proportion who obtained more than 50% of the maximum possible pain relief with placebo varied from 7% to 37% across the trials; with the active drugs the variation was from 5 to 63%. Mean placebo scores were related to the mean score for the active treatments in each study; the higher the mean active score, the higher the mean placebo score. This relationship disappeared when median values were used. Medical folklore has it that the amount of relief obtained with placebo is one-third of the maximum possible (and does not vary), and that one-third of patients respond to placebo. The results show that the amount of relief obtained with placebo varies considerably between patients, that 38% of patients obtained more than 10% of the maximum possible relief, and 16% obtained greater than 50%. In double-blind, randomised parallel-group studies of high quality placebo scores should not vary. Despite these conditions being met the placebo scores did vary. The previous explanation, of a relationship between the mean placebo scores and the mean scores for the active treatments was not supported.

Impact of laparoscopic surgery in the treatment of chronic abdominal pain syndrome

Chronic abdominal pain syndrome is becoming increasingly important with regard to the quality of life of the patients and its social and economic impact, in terms of cost of hospitalization, income loss due to sick leave, and pharmaceutical costs for treatments which fail to offer either significant clinical improvement or resolution of the pain symptoms. The main symptom is chronic abdominal pain, which may vary in intensity and may be associated with constipation and episodes of vomiting, when the clinical picture evolves toward one of subocclusion or total occlusion of the bowel. We considered the following criteria in our selection of patients for this study: 1) quality of life, 2) constant use of antispastic and analgesic medications, 3) absence of any other diagnosticable pathology prior to the operation. From August 1992 to April 2000 we operated on 105 patients with this syndrome (16 males and 89 females). Among these 8 patients had never been subjected to a laparotomy, while 97 had previously undergone surgical procedures (126 laparotomies). In the first 85 patients in the series (81%) we used a 10 mm laparoscope (0-30 degrees) to evaluate the presence of abdominal-visceral adhesions based on the type of surgery the patient had undergone previously, as well as the location of the pain reported by the patient. In 41 cases (48.2%) the pneumoperitoneum was obtained with the Veress needle. In another 44 cases (51.8%) the Hasson technique was used. Since June 1999, we have carried out the exploration of the abdominal cavity in 20 patients (19%) using a trocar and 2.2 mm laparoscope in the left hypochondrium along with a mini-trocar placed either in the right or left flank. (The positioning of the trocars depended on the previous surgical procedures performed). The exploration included inspection of the abdominal cavity. In 8 of the patients the procedure was carried out under local anaesthesia We performed laparoscopic adhesiolysis in 93 cases; in 7 cases no signs of adhesions were seen, while in another 5 cases it was necessary to convert the original laparoscopic procedure to a laparotomy. The types of adhesions found were fine-filmy (46%), dense-vascularised (46%), and cohesive (16%). In 6 cases during lysis of the adhesions complications of serous-muscular lesions occurred, which required laparotomic repair. In 5 cases we diagnosed a pathological condition which was not suspected. The average postoperative hospital stay was 2 days (range: 1-7); no major postoperative complications were noted. In the course of the follow-up of 78 patients over an average of 37 months (range: 6-72) the results obtained were as follows; 47 patients (60.2%) had complete pain relief, 18 patients (23.1%) had partial pain relief, and the remaining 13 patients (16.7%) had no significant pain relief. Laparoscopic exploration in patients with chronic abdominal pain is technically feasible in a simple manner in most patients. By means of careful and accurate preoperative selection of the patients partial if not complete pain relief can be achieved in a high percentage of cases (83.3% in our series).

Intrathecal morphine (ITM) for postoperative pain control in children: a comparison with nalbuphine patient controlled analgesia (PCA).

This is a retrospective study covering the ten-year period 1984-1993. Single shot spinal morphine (ITM) is compared with PCA nalbuphine for postoperative pain relief in children having abdominal or thoracic procedures. The records of 52 patients meeting selection criteria were examined. Nursing and physician notations were reviewed for hourly pain assessments, evidence of associated complications, respiratory depression, nausea and or vomiting, pruritus, and urinary retention. ITM provided significantly better pain relief (2.2 h in pain) during the first 24 h postoperatively than PCA nalbuphine (9.2 h in pain). With the exception of urinary retention which was significantly more frequent following ITM (58.6%) compared to PCA nalbuphine (8.7%), narcotic related complications were not different between the two groups. No difference in duration of hospital stay or ICU stay could be demonstrated. We conclude that ITM provides better pain relief, without more serious complications, than PCA nalbuphine. We recommend it as a safe, effective technique to treat postoperative pain in children following thoracic or upper abdominal procedures.

Caudal epidural blocks for elderly patients with lumbar canal stenosis.

OBJECTIVE: To determine the efficacy of caudal epidural blocks (CEB) in relieving pain and the duration of pain relief with CEB in elderly patients suffering from degenerative lumbar canal stenosis (LCS). DESIGN: This study was a descriptive, prospective study with a 10-month follow-up. PARTICIPANTS AND SETTING: Thirty patients, 76 +/- 6.7 years of age, with leg discomfort with or without back pain and with LCS documented by magnetic resonance imaging (MRI) within 1 year of the study, were recruited from the outpatient clinic of the Cleveland Clinic Florida. None of the subjects had received CEB or surgery for their leg discomfort and none had relief of pain by analgesics alone. MEASUREMENTS AND INTERVENTIONS: Subjects received a total of three doses of 0.5% Xylocaine with 80 mg Depo-Medrol into the caudal epidural space through the sacral hiatus at weekly intervals. The Roland 5-point pain rating scale was utilized before and at 2-month intervals up to 10 months after the CEB was administered. MRI was used to identify the degree of LCS. RESULTS: The degree of LCS on admission was moderate in 66.7% (n = 20) of the patients, mild in 23.3% (n = 7), and severe in the remaining 10% (n = 3). Patients had LCS involving 2.4 +/- 0.49 lumbar vertebrae. The degree of LCS is directly correlated with the pain level before CEB. After CEB, the pain level changed from 3.43 +/- 0.82 to 1.5 +/- 0.86 (P < 0.0000), with a significant relief of pain up to 10 months (the end of observation). The duration of pain relief ranged from 4 to 10 months (P < 0.0001). CONCLUSION: CEB offers significant pain relief and appears to be a reasonable therapeutic option among elderly patients with LCS. This alternative seems particularly important among patients with poor response to drug therapy and who are either poor surgical risks or who have refused surgery.

Trigeminal neuralgia: what are the important factors for good operative outcomes with microvascular decompression.

BACKGROUND: Microvascular decompression has been widely used as the first choice in treating trigeminal neuralgia, but in a few patients, facial pain cannot be effectively controlled by microvascular decompression. We sought to clarify the important factors for good operative outcomes. METHODS: We reviewed 62 patients with trigeminal neuralgia treated by microvascular decompression during the period 2000 through 2002, including clinical presentation, operative findings, techniques, and outcomes. Neurovascular conflicts were divided into single contact, contact and indentation, single adhesion, adhesion and indentation, and trigeminal nerve atrophy. Operative outcomes were graded into immediate postoperative complete pain relief (excellent), delayed postoperative complete pain relief (better), significant pain relief (good), and no response to microvascular decompression (poor). RESULTS: All patients' presentations were typical at the time of pain onset, but the symptom in 17 patients changed to atypical before surgery. During operation, single contact and single adhesion was found in 14 patients and 15 patients, respectively; contact or adhesion in combination with indentation was found in 7 patients and 18 patients, respectively; atrophy occurred in 8 patients. Postoperatively, immediate and delayed complete pain relief was achieved in 32 (51.6%) patients and 17 (27.4%) patients, respectively; 11(17.7%) patients got significant pain relief; and 2 patients showed no response. The overall rate of complete pain relief in patients with shorter duration, typical presentation, artery compression and complete decompression was higher than that in patients with longer duration, atypical presentation, venous compression, and incomplete decompression. CONCLUSIONS: Shorter duration, typical presentation, single artery compression, and complete decompression are the positive factors for better operative outcomes with microvascular decompression. Worse outcomes are usually related to venous compression, longer duration, and atypical presentation.

Difference in pain relief after trigger point injections in myofascial pain patients with and without fibromyalgia.

OBJECTIVE: To compare responses to trigger point (TrP) injection between patients having both myofascial pain syndrome (MPS) caused by active TrPs and fibromyalgia syndrome (FMS) and patients with MPS due to TrPs but without FMS. DESIGN: Prospective design blinded measurement, before- after trial. SETTING: A pain control medical clinic. PATIENTS: Group 1: MPS + FMS; Group 2: MPS only. All patients (9 in each group) had active TrPs in the upper trapezius muscle. INTERVENTION: Myofascial TrP injection with 0.5% xylocaine. MAIN OUTCOME MEASURES: Subjective pain intensity (PI), pain threshold (PT), and range of motion (ROM) were assessed before, immediately after, and 2 weeks after TrP injection. RESULTS: In a comparison of preinjection measures to immediate postinjection measures, only ROM was significantly improved (p < .05) in Group 1 patients; all three parameters were significantly improved (p < .05) in the Group 2 patients who had only MPS. Two weeks after injection, both groups showed significant improvement (p < .05) in all three measured parameters as compared to preinjection measurements. In a comparison of the two groups, the immediate effectiveness of TrP injection was significantly less (p < .05) in Group 1 than in Group 2 for all three parameters. Two weeks after injection, the degree of improvement in PT or ROM (but not PI) was not significantly different between two groups. Postinjection soreness (different from myofascial pain) was more severe, developed sooner, and lasted longer in Group 1 than in Group 2. CONCLUSION: Trigger point injection is a valuable procedure for pain relief for patients in both group. Patients with FMS are likely to experience significant but delayed and attenuated pain relief following injection of their active TrPs compared to myofascial pain patients with similar TrPs but without FMS. Also, FMS patients are likely to experience significantly more postinjection soreness for a longer period of time.