Trigemino-cervical reflex abnormalities in patients with migraine and cluster headache.

BACKGROUND: Head pain arises within the trigeminal nociceptive system. Current theories propose that the trigeminal system is intimately involved in the pathogenesis of migraine. Short-latency responses can be recorded in sternocleidomastoid muscles after stimulation of the trigeminal nerve (trigemino-cervical reflex). This brainstem reflex could be a suitable method to evaluate the trigeminal system in migraine and CH. OBJECTIVE: The aim of the present study was to further elucidate the pathophysiology of migraine and cluster headache (CH) with special reference to the involvement of the central trigeminal system in the different forms of primary headache. METHODS: The trigemino-cervical reflex was investigated in 15 healthy subjects, in 15 patients having migraine with aura, in 15 patients with migraine without aura, and in 10 patients with CH. RESULTS: Significant abnormalities were observed in a great number of patients with both types of migraine and CH during the headache attacks, but only in migraine patients during the interictal period. The alterations are bilateral in migraine, unilateral in CH. CONCLUSIONS: Our results further support the relevance of brainstem mechanisms in the pathogenesis of migraine rather than of CH. These data, taken together with that from experimental head pain and functional imaging studies, demonstrate that primary headache syndromes may be distinguished on a functional basis by areas of activation specific to the clinical syndrome.

The ultrasonographic appearance of the femoral nerve and cases of iatrogenic impairment.

OBJECTIVE: To assess the feasibility of ultrasonography of femoral nerves in a cadaveric specimen, healthy volunteers, and patients. METHODS: In 1 unembalmed cadaveric specimen (female, 90 years) and 20 healthy volunteers (9 male and 11 female, 18-50 years; n = 40 scans), the topographic features, cross-sectional shapes (oval or triangular), and cross-sectional areas of the femoral nerves were evaluated by ultrasonography (5- to 12-MHz broadband linear array). In a subsequent study, 7 consecutive patients with postoperative findings assigned to the femoral nerve were evaluated and assessed by a neurologist. RESULTS: The mean +/- SD anteroposterior and mediolateral diameters of the femoral nerves in the volunteers were 3.1 +/- 0.8 and 9.8 +/- 2.1 mm, respectively, at an average cross-sectional area of 21.7 +/- 5.2 mm2. The cross-sectional shape was oval in 67.5% superior to the inguinal ligament and in 95% inferior to the ligament. The infrainguinal femoral nerve showed variable distances to the femoral artery. In the subsequent patient study, 5 patients had swelling of the femoral nerve in the affected side. In 1 patient, the nerve had a blurred echo structure due to a hematoma. In 1 patient, major damage of the femoral nerve was ruled out clearly. CONCLUSIONS: Ultrasonography allows the depiction and assessment of the femoral nerve from about 10 cm superior to 5 cm inferior to the inguinal ligament. In this region, ultrasonography is helpful in detection of impairments and, therefore, in decisions about planning and even acceleration of further treatment.