Thalamic pain syndrome: anatomic and metabolic correlation.

We report a patient with thalamic pain induced by stereotactic biopsy; therefore, the location of the anatomical lesion causing the syndrome is precisely known. The location of the lesion was confirmed by postoperative magnetic resonance imaging and computed tomography. The metabolic consequences of the anatomic lesion were documented by positron emission tomography using as marker 18F-fluoro-2desoxy-glucose. The anatomic, metabolic, and clinical findings are discussed, as well as the neurophysiologic theories of the mechanisms of the thalamic pain syndrome.

Histologic characteristics of the lateral pterygoid muscle insertion to the temporomandibular joint.

This study used low-power light microscopy to examine the histologic organization of the lateral pterygoid muscle interface with the temporomandibular joint. The sample included parasagittal sections of 20 intact temporomandibular joints from young adults (mean age 26.2 years) at autopsy. The lateral pterygoid muscle showed no consistent divisions into separate anatomic muscle heads at the insertion. The muscle fibers attached to the pterygoid fovea of the condyle immediately inferior to the articular surface in all cases. Some additional fibers inserted superiorly into the more anterior part of the articular disc in a minority of cases (31%). Fibers inserting into the disc represented only 2.4% to 6% of the total superior-inferior length of the muscle insertion. It is hypothesized that the muscular force exerted by these few fibers inserting into the disc would not be sufficient to displace the disc anteriorly to the condyle. There were two histologic types of insertion of the lateral pterygoid muscle to the condyle. The superior part of the insertion was characterized by an identifiable tendon inserting through fibrocartilage. In the inferior part of the insertion, the muscle attached to periosteum without an obvious tendon. The presence of this tendon must be recognized in interpretation of soft tissue temporomandibular joint imaging.

The use of methylergonovine (Methergine) in the initial control of drug induced refractory headache.

This study investigated the efficacy of methylergonovine maleate (Methergine) in the treatment of drug induced refractory headache (DIRH). Sixty consecutive patients (51 female and 9 male) diagnosed with DIRH were treated with methylergonovine maleate for a maximum of six months, using a within subject design. All patients were withdrawn from the medications they were taking upon entering the study. Concurrently, they were given 0.2-0.4 mg of methylergonovine maleate three times a day. Patients were provided the means to control breakthrough episodes of headache. Treatment outcome was assessed using a patient self-report scale (much better, better, same, worse, and much worse), and also visual analogue pain intensity scales. The side effects of the drug were assessed with patient self-report. Methylergonovine was effective in 44 (73%) patients. Twelve (20%) patients reported unchanged pain and 4 (6%) patients got worse. Side effects were reported by 24 patients. These were predominantly abdominal cramping. It is concluded that methylergonovine maleate is effective in the initial control of drug induced refractory headache. However, because methylergonovine is a metabolic byproduct of methysergide, the possibility or fibrotic disorders needs to be considered if methylergonovine is to be used for long term therapy.

The effects of streptomycin/lidocaine block on trigeminal neuralgia: a double blind crossover placebo controlled study.

This study investigated the long term effect of a peripheral sensory block using streptomycin sulphate on trigeminal neuralgia. A total of twenty subjects, thirteen with idiopathic trigeminal neuralgia (ITN) and seven with traumatic trigeminal neuralgia (TTN) were studied. A double-blind placebo controlled randomized design was used. After the clinical assessment subjects were randomly assigned to receive either 1 g of streptomycin with 3 ml 2% lidocaine, or 3 ml lidocaine alone. The injections were performed adjacent to the branches that served the painful site. These were intraoral injections, more specifically infraorbital and inferior alveolar blocks. Patients received five blocks of either streptomycin/lidocaine or lidocaine alone for a period of five consecutive weeks. On the sixth week they were crossed over. Measures of pain intensity and pain frequency were used to assess treatment outcome. Patients also recorded their side-effects. Repeated measures analysis of variance was used to compare the treatment outcomes between the active and placebo groups. There was no statistically significant differences in the treatment outcomes regarding frequency and intensity of pain attacks. The sensory function of the treated nerves was also not affected. Side effects including facial swelling and pain were a common finding in the patients receiving streptomycin. This study demonstrated no beneficial effects of streptomycin blockade for idiopathic and traumatic trigeminal neuralgia.