Loren M. Fishman, MD Craig Konnoth Bernard Rozner, PhD
From Columbia College of Physicians and Surgeons, New York, New York (LMF); Fordham University New York, New York (CK); and Deaconess and Brigham and Women’s Hospitals, Harvard Medical School, Boston, Massachusetts (BR).
CME Article ● 2004 Series ● Number 1
All correspondence andrequests for reprints should be addressed to Loren M. Fishman, MD, 3 East 83rd Street, New York, New York 10028. 0894-9115/04/8301-0042/0 American Journal of Physical Medicine & Rehabilitation Copyright © 2003 by Lippincott Williams & Wilkins
Botulinum Neurotoxin Type B and Physical Therapy in the Treatment of Piriformis Syndrome
A Dose-Finding Study
ABSTRACTFishman LM, Konnoth C, Rozner B: Botulinum neurotoxin type B and physical therapy in the treatment of piriformis syndrome: A dose-ﬁnding study. Am J Phys Med Rehabil 2004;83:42–50. Objective: To measure dosage effects of botulinum neurotoxin type B with physical therapy in piriformis syndrome. Design: Prospective study of consecutive patients complaining of buttock pain and sciatica, measuringserial H-reﬂex tests in ﬂexion, adduction, and internal rotation; visual analog scale; and adverse effects at 0, 2, 4, 8, and 12 wks. We used an electrophysiologic criterion for piriformis syndrome: a 1.86msec prolongation of the H-reﬂex with the ﬂexion, adduction, and internal rotation test. Four piriformis syndrome groups were identiﬁed. Serial groups were injected once with either 5000, 7500,10,000, or 12,500 units of botulinum neurotoxin type B in successive months under electromyographic guidance in four separate locations of the affected piriformis muscle, with a 1-mo safety observation period between groups. Patients received physical therapy twice weekly for 3 mos. Results: The ﬂexion, adduction, and internal rotation test and visual analog scale declined signiﬁcantly, correlating at72% sensitivity and 77% speciﬁcity. A total of 24 of 27 study patients had 50% pain relief. Mean visual analog scale score declined from 6.7 to 2.3. A volume of 12,500 units of botulinum neurotoxin type B was superior to 10,000 units at 2 wks postinjection. The most severe adverse effects were dry mouth and dysphagia, approaching 50% of patients at 2 and 4 wks. Conclusion: Physical therapy and12,500 units of botulinum neurotoxin type B seem to be safe and effective treatment for piriformis syndrome. In addition, the ﬂexion, adduction, and internal rotation test seems to be an effective means of diagnosing piriformis syndrome and assessing its clinical improvement. Injection may beneﬁt patients for 3 mos. Key Words: Piriformis, Electrodiagnosis, Chemodenervation, Rehabilitation
Am. J.Phys. Med. Rehabil.
Vol. 83, No. 1
Figure 1: The H-reﬂex elicits the Achilles tendon reﬂex through electrical stimulation of the sciatic nerve at the popliteal fossa. Standard EMG equipment measures the latency of this monosynaptic reﬂex in 10 5 secs and 10 6 volts. It is generally studied in the anatomical position (A). The FAIR test compares the H-reﬂex obtained in the anatomical positionwith H-reﬂexes obtained in ﬂexion adduction and internal rotation, in which the piriformis muscle is stretched tightly against the sciatic nerve (B). Prolongation of the H-reﬂex by 1.86 msecs (3 standard deviations beyond the mean), indicating signiﬁcant compression of the nerve by the muscle, is diagnostic of piriformis syndrome (C).
Objectives: On completion of this article, the reader shouldbe able to (1) state clinical and electrophysiologic criteria for piriformis syndrome, (2) give two clinical motives to utilize more than one botulinum neurotoxin, and (3) explain the technique for botulinum toxin injection of the piriformis muscle, with clinical and electrophysiologic follow-up. Level: Advanced. Accreditation: The Association of Academic Physiatrists is accredited by the...