Monday, 2 December 2013

Trigeminal neuralgia - Treatments in conventional medicine perspective

Trigeminal neuralgia is defined as a condition of episodes of intense facial pain as a result of the affect of trigeminal nerve, containing 3 branches. The first (upper) branch includes the eye, eyebrow, and forehead. The second (middle) branch corresponds to the upper lip, upper teeth, upper gum, cheek, lower eyelid, and side of the nose. The third (lower) branch involves the lower lip, lower teeth, lower gum, and one side of the tongue. It also includes a narrow area that extends from the lower jaw in front of the ear to the side of the head(1). The pain is nearly always unilateral, and it may occur repeatedly throughout the day(2).
V.1. Treatment in conventional medicine perspective
A. Medication
1. Carbamazepine 
Carbamazepine is currently the drug of first choice in the treatment of trigeminal neuralgia. However, it is reported as efficacious in only 70-80% of patients, and can be associated with adverse effects such as drowsiness, confusion, nausea, ataxia, nystagmus and hypersensitivity, which may necessitate discontinuation of medication(19).

2. Topiramate
In the trials comparing topiramate with carbamazepine are all poor in methodological quality. A meta-analysis of these studies showed that the overall effectiveness and tolerability of topiramate did not seem to differ from carbamazepine in the treatment of classical trigeminal neuralgia. However, the meta-analysis yielded a favourable effect of topiramate compared with carbamazepine after a treatment duration of 2 months. Results were limited due to the poor methodological quality and the geographic localization of the randomized controlled trials identified. Therefore, large, international, well conducted, randomized controlled trials are needed to further assess the relative efficacy and tolerability of topiramate and carbamazepine in this indication(20)
Side effects include Loss of appetite, dizziness, and tingling sensations, etc.

3. Lamotrigine
In the study of 21e patients with TN administered with LTG in comparison to CBZ. in the clinical trials comprised two phases of 40 days each, with an intervening three-day washout period, showed that oth on VAS and VRS assessments, in terms of proportion of patients, CBZ benefitted 90.5% (19/21) of the patients with pain relief (p < 0.05), in contrast to 62% (13/21) from LTG. On VAS assessment, of the 13 patients who gained pain relief from LTG and 19 from CBZ, 77% (10/13) obtained a "complete" degree of pain relief from LTG, as compared with 21% (4/19) from CBZ. On VRS assessment, with LTG, 84% (11/13) of the patients accomplished "much better" degree of pain relief, as compared with 26% (5/19) with CBZ. On LTG, 67% (14/21) of patients endured general pharmacological side effects, as compared with 57% (12/21) of patients on CBZ (p > 0.05). Meanwhile, LTG inflicted 14% (3/21) of the patients with haematological, hepatic and renal derangements, as compared with 48% (10/21) on CBZ(21).
Side effects include nausea, dizziness, headaches, coordination problems, etc.

4. Etc.

B. Surgical treatments 
1. Peripheral neurectomies, a minimally invasive treatment for trigeminal neuralgia
In the study to investigate the efficacy of peripheral neurectomy as a surgical procedure in the treatment of trigeminal neuralgia and to evaluate the results obtained by this procedure and their recurrences in a period of three years followup, researchers at the Modern Dental Collage & Research Centre, showed that peripheral neurectomy is one of the oldest, minimal invasive forms of surgery, well tolerated by the patient and can be done under local anesthesia(22)
Others suggested that peripheral neurectomy is thus a safe and effective procedure for elderly patients, for those patients living in remote and rural places that cannot avail major neurosurgical facilities, and for those patients who are reluctant for major neurosurgical procedures(23).
According to the study by Dr. Freemont AJ, and DR. Millac P. Of 49 patients ultimately maintained pain-free by non-medical means, 26 underwent peripheral neurectomy. Twenty of these achieved excellent pain control in the longer term and 5 of the remaining 6 became more responsive to carbamazepine after operation. Seven patients required repeat neurectomies(24).

2. Trigeminal Root Compression of trigeminal nerve 
In the  study of the Efficacy and safety of root compression of trigeminal nerve for trigeminal neuralgia with out evidence of vascular compression, found that all patients were pain free after the procedure; there was a 27% relapse in a mean time of 10 months, but 83% of these patients were adequately controled by medical treatment, and only 17% needed a complementary procedure for pain relief. Also we found that 63% of the patients complained of a partial loss of facial sensitivity, but only one patient presented with a corneal ulcer. There were a 6.7% rate of significant complications. We concluded that Trigeminal Root Compression is a safe and effective option for patients with primary trigeminal neuralgia without vascular compression(25).
TN is frequently associated with nerve root entry zone demyelination in MS and patients with nerve root vascular compression. The characteristics of the TN and response to PSR are similar in both groups. Persistent vascular compression increases the risk of recurrent TN after PSR(26).

3. Microvascular decompression (MVD)  
In the study to evaluate the long-term efficacy of microvascular decompression (MVD) and to identify the factors affecting outcome in patients treated for primary trigeminal neuralgia (TN), researchers at the
Hôpital Neurologique Pierre Wertheimer, University of Lyon, found that Pure MVD can offer patients affected by a primary TN a 73.38% probability of long-term (15 years) cure of neuralgia. The presence of a clear-cut and marked vascular compression at surgery (and possibly-although not yet reliably--on preoperative magnetic resonance imaging) is the guarantee of a higher than 90% success rate(27).
In Microvascular decompression (MVD), the Complete pain relief (off medication) achieved in 71% of patients at 10 years. Overall 84% of responders to questionnaires expressed satisfaction with the operative outcome, the mean duration of TGN was 80 months and mean post-operative follow-up of 7 years. No mortality reported in this series(28).

4. Gamma Knife surgery
In the comparison of data across previous reports hampered by differences in treatment protocols, lengths of follow-up, and outcome criteria, researchers at the Sint Elisabeth Hospital, Tilburg found that
in the idiopathic TN group, rates of adequate pain relief, defined as BNI Pain Scores I-IIIB, were 75%, 60%, and 58% at 1, 3, and 5 years, respectively. In the multiple sclerosis (MS)-related TN group the rates of adequate pain relief were 56%, 30%, and 20% at 1, 3, and 5 years, respectively. Repeated GKS was as successful as the first. An analysis of our treatment strategy of repeated GKS showed rates of adequate pain relief of 75% at 5 years in the idiopathic TN and 46% in the MS-related TN group. Somewhat bothersome numbness was reported by 6% of patients after the first treatment and by 24% after repeated GKS. Very bothersome numbness was reported in 0.5% after the first GKS and in 2% after the second treatment(29).
During the radiosurgical procedure, 19 patients (2%) suffered anxiety or syncopal episodes, and 2 patients suffered acute coronary events. Treatments were incompletely administered in 12 patients (1.2%). Severe pain was a delayed complication: 8 patients suffered unexpected headaches, and 9 patients developed severe facial pain. New motor deficits developed in 11 patients, including edema-induced ataxia in 4 and one case of facial weakness after treatment of a vestibular schwannoma. Four patients required shunt placement for symptomatic hydrocephalus, and 16 patients suffered delayed seizures(30).

5. Radiofrequency

Only Patients with a  good to excellent pain relief with a diagnostic trigeminal ganglion block and if the pain relief is of a short duration may be suitable candidates for percutaneous RF rhizotomy.  It is performed by destruction of the trigeminal ganglion or roots using RF. RF is the most common percutaneous procedure used to treat TN, especially in elderly patients(31).
According to the study of an analysis of 16 346 treated nodules in 13 283 patients, between January 1999 and November 2010. Five patients (0.038%) died: two from intraperitoneal hemorrhage, and one each from hemothorax, severe acute pancreatitis and perforation of the colon. In 16 346 treated nodules, 579 complications (3.54%) were observed, including 78 hemorrhages (0.477%), 276 hepatic injuries (1.69%), 113 extrahepatic organ injuries (0.691%) and 27 tumor progressions (0.17%). The centers that treated a large number of nodules and performed RFA modifications, such as use of artificial ascites, artificial pleural effusion and bile duct cooling, had low complication rates(32).
6. Balloon compression
In the retrospective study of 121 patients treated with balloon compression of the rootlets behind the Gasser ganglion from 1995 to 2007 showed that balloon compression is considered in the literature to be a safer procedure than other percutaneous surgeries, especially for postoperative sensitive disorders. The best indications seem to be trigeminal neuralgia in older patients or pain due to multiple sclerosis and neuralgia involving the V1 territory(33).
According to researches at the University Clinical Centre Maribor, pain relief was reported in 25 (93%) patients. In two patients, the pain remained the same. The pain free period ranged from 2 to 74 months (median 15 months). A mean duration of analgesia was longer in patients with ideal pear shape of balloon at the time of the procedure compared to nonideal shape (P = 0.01). No major complications occurred in our group of patients(34). 
7. Glycerol rhizolysis
In the study to examine the pathophysiological mechanisms of trigeminal neuralgia and the mechanisms underlying pain relief after percutaneous retrogasserian glycerol rhizolysis (PRGR), indicated that relief of pain after PRGR depends on the normalization of abnormal temporal summation of pain, which is independent of general impairment of sensory perception. Assessment of the temporal summation of pain may serve as an important tool to record central neuronal hyperexcitability, which may play a key role in the pathophysiological changes in trigeminal neuralgia(35).
According to researchers at the All India Institute of Medical Sciences, seventy-nine patients underwent either PRGR (n = 40) or RF thermocoagulation (n = 39). A total of 23 patients (58.9%) in the PRGR group and 33 patients (84.6%) in the RF group experienced excellent pain relief. The mean duration of excellent pain relief in the PRGR and RF groups was comparable. By the end of the study period, 39.1% patients in the PRGR group and 51.5% patients in the RF group experienced recurrence of pain(36).
8. Radiofrequency rhizotomy
In the reevaluate the results of radiofrequency rhizotomy and review the effectiveness of other surgical procedures for the treatment of trigeminal neuralgia, Dr. Taha JM, and Dr. Tew JM Jr. at the University of Cincinnati College of Medicine, found that
1) percutaneous techniques and posterior fossa exploration offer advantages and disadvantages,
2) radiofrequency rhizotomy is the procedure of choice for most patients undergoing first surgical treatments, and
3) MVD is recommended for healthy patients who have isolated pain in the first ophthalmic trigeminal division or in all three trigeminal divisions and patients who desire no sensory deficit(37)
Fifty-four of the 89 patients underwent 146 RF-TR procedures for both sides and 35 underwent 40 RF-TR procedures for one side. Complete pain relief or partial satisfactory pain relief was achieved on the medically treated side in 35 patients. During follow-up, 36 patients required the second procedure and 7 required the third procedure. Acute pain relief was reported in 86 (96.6%) patients. Early (<6 months) pain recurrence was observed in 11 (12.3%) and late (>6 months) recurrence in 25 (28.0%) patients. Complications included diminished corneal reflex in four (2.1%) patients, keratitis in two (1.1%), masseter dysfunction in four (2.1%), dysesthesia in two (1.1%), and anesthesia dolorosa in one (0.5%), according to the study of Ankara University, Faculty of Medicine(38).

9. Etc.

Unfortunately, all neurosurgical interventions are helpful in relieving pain but with certain side effects. In the study to assess the efficacy of neurosurgical interventions for classical trigeminal neuralgia in terms of pain relief, quality of life and any harms and to determine if there are defined subgroups of patients more likely to benefit, showed that there is very low quality evidence for the efficacy of most neurosurgical procedures for trigeminal neuralgia because of the poor quality of the trials. All procedures produced variable pain relief, but many resulted in sensory side effects. There were no studies of microvascular decompression which observational data suggests gives the longest pain relief. There is little evidence to help comparative decision making about the best surgical procedure. Well designed studies are urgently needed(39) and various surgical procedures have been reported for the treatment of this condition, but there is no agreement on the best management of these patients. There are no differences in the short term results among different procedures for TN in MS patients. Each technique demonstrate advantages and limits in terms of long term pain, recurrence rate and complication rate(40).

No comments:

Post a comment