Abstract Details

Title Peroneal H-Reflex in Piriformis Syndrome

Topic Peripheral Nerve

Presentation(s) P07 - (-)

Poster/Presentation
Number 057

Objective

Background BACKGROUND: The electro-diagnostic studies defining piriformis syndrome was elaborated according to the peroneal H-reflex. The aim is to define electrical criteria with delay in latency and decreased amplitude during stress testing.

Design/Methods DESIGN/METHODS: 18 patients suspected to suffer from piriformis syndrome after ruling out other causes of spinal affection were tested with EMG exam on both sides in neutral and dynamic positions: the hip in adduction-internal rotation. The amplitude and latency of the H-reflex on the peroneal nerve were studied and compared with the opposite painless side.

Results RESULTS: The latency of the peroneal H-reflex at the normal side was delayed by 0.7msec(0 to 2msec) with the stress test. At the painfull side, the delay was 5.4msec(2 to 10msec), and when we excluded two patients with 2 msec delay confirmed not having piriformis syndrome, the average was 6msec(3 to 10 msec). The amplitude of the peroneal H-reflex at the normal side was decreased by 14% with the stress test, 70%(30% to 100%) at the painfull side and 74%(50% to 100%) after excluding patients confirmed not having piriformis syndrome.

Conclusions CONCLUSIONS: Our results confirm the importance of the peroneal H-reflex in diagnosing piriformis syndrome. The delay of latency at stress testing should be considered positif above 3msec. At the same time the amplitude of the reflex has decreased more than 50% compared with the reflex in neutral position of the limb. Combined to clinical exam, these values are considered highly suggestive of piriformis syndrome.

Authors/Disclosures
Chaker F. Khamis, MD (Sacre Coeur Hospital) PRESENTER	No disclosure on file
Olivier Simon	No disclosure on file

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