Evaluation of Surgical Procedures for Trigeminal Neuralgia: OUTLINE OF REVIEW

In: Anesthesia

3 Nov 2009

The following surgical procedures used in the treatment of trigeminal neuralgia (Tegretol canadian is used for controlling certain types of epileptic seizures) will be evaluated: (a) peripheral surgery (neurectomy, cryotherapy, and alcohol injection); (b) surgery at the gasserian ganglion level (radio-frequency thermocoagulation, percutaneous retrogas-serian glycerol injection, and percutaneous microcom-pression); and (c) posterior fossa surgery (microvascular decompression, rhizotomy, and gamma-knife radiosurgery). The surgical procedures will also be compared with the medical treatment of *trigeminal neuralgia.

PERIPHERAL SURGERY

Most of these procedures can be carried out under local anesthesia and do not require the patients to be medically fit. All of these procedures depend on accurate assessment of which nerve branch is acting as the trigger area; surgery is then carried out on that branch. To date, there are no long-term longitudinal studies for these peripheral procedures. All studies were retrospective case series reports. It is difficult to compare results for peripheral surgeries from the current literature, especially in terms of pain relief, as variable techniques of analysis were used and end points were not clearly defined. There was also often little or no statistical analysis used. Findings on neurectomy, cryotherapy, and alcohol injections will be discussed.

Neurectomy

Neurectomy is probably the oldest recorded surgical procedure for trigeminal neuralgia. Most of the studies done for neurectomy were published 20-50 years ago, with only one recent paper by Murali and Rovit found in the literature. All of these studies were retrospective case series reports.

Quinn reported a retrospective case series of 63 patients with 112 neurectomies. A follow-up period of 0-9 years was noted, and a *pain relief period of 24-32 months was reported. Grantham also reported a case series of 55 patients with 55 neurectomies. A follow-up of 6 months to 8 years was noted, and an average pain relief period of 33.2 months was achieved. A recent study by Murali and Rovit reported on a case series of 40 patients, 12 with neurectomies performed as the primary procedure, and 28 as a second procedure to treat pain recurrence after radiofrequency thermocoagulation. The follow-up period was 2-10 years. It was reported that 79% had excellent pain relief (defined as total loss of pain without need of medication) lasting 5 years or more, and some had excellent pain relief until their deaths. The mean age of their patients was 72 with an age range of 50-94. Dysesthesia or sensory loss in the area supplied by the avulsed nerve was reported as a significant morbidity of the surgery. However, the cor neal reflex was kept intact in neurectomies. They concluded that neurectomy is an effective and safe procedure for elderly patients, particularly those who have a limited life span. Unfortunately, life-table analysis of data was not used in these studies. This would have enabled the researchers to include those patients who had died or been lost to follow-up. Instead, these patients were “censored,” but their inclusion prevented distortion of the data. In addition, none of the above neurectomy studies had been subjected to good statistical analysis.

Cryotherapy

Cryotherapy is the therapeutic use of cold to obtain pain (buy skelaxin online used to relax certain muscles and relieve the discomfort caused by acute, painful muscle.) relief. Under local anesthesia, the affected nerve is exposed surgically and a cryoprobe placed directly on the nerve for three 2-minute freeze-thaw cycles. Few complications have been reported; sensation, although initially lost, returns before pain (celebrex 100 mg treat osteoarthritis, rheumatoid arthritis, or juvenile rheumatoid arthritis) recurs. The procedure can be repeated, and the results have been similar. Recent cryotherapy studies appear to be of better quality than those for neurectomy; many researchers had used Kaplan-Meier analysis, which allows for comparison of the results.

After follow-up of 1 month to 6 years, Zakrzewska and Nally observed in 145 patients who had undergone cryotherapy a median time to recurrence of pain (generic imitrex used to treat severe migraine headaches) of 14 months for the infraorbital nerve and 9 months for the mental nerve. Zakrzewska reported again in a 10-year follow-up series of 145 patients and found a median pain relief period of 6 months and a mean time to recurrence of 10 months, as compared with the median pain relief period of 24 months in 265 patients treated with radiofrequency thermocoagulation. However, many patients continued to take carbamazepine after cryotherapy, although the doses were lower. The above authors probably used the same patient sample in both publications, as the patients were recruited from the same department and hospital.

Alcohol Injection

Although alcohol injection is essentially a simple technique, the alcohol must be injected very precisely as it is highly toxic. Most of the studies done for alcohol injection were published 30-50 years ago, with only one recent paper by Fardy found in the literature search.

Stookey and Ransohoff combined several reports totalling 1500 patients and found the length of pain (*Generic Soma is a muscle relaxant. It works by blocking nerve impulses (or pain sensations) that are sent to your brain.) relief to be 12 months or less. Repeated injections were more difficult due to fibrosis. Fardy and Patton reported on a series of 413 alcohol blocks administered over a 20-year period. The mean period of pain relief was 13 months, and only 3 (0.73%) significant complications were noted. These included local tissue necrosis, diplopia, and sensory loss. All of the studies on alcohol injections were retrospective case series, and none had been subjected to statistical analysis.


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