Musculoskeletal dysfunction and drop foot: diagnosis and management using OMM.

To the Editor: I read with great interest the case report in the December 2009 issue of JAOA— The Journal of the American Osteopathic Association by John M. Lavelle, DO, and Mark E. McKeigue, DO,1 regarding osteopathic manipulative treatment (OMT) of a patient with drop foot. Lavelle and McKeigue1 reported that a single 15-minute OMT session resolved their patient’s symptoms. I have had extensive experience treating patients with OMT for nerve compression, particularly carpal tunnel syndrome, over 3 decades.2-5 Yet, I have never enjoyed the experience of seeing a patient get off the examination table with instantaneous recovery of three grades of muscle strength—from a grade of 1/5 to one of 4/5. I commend the authors’ recognition of the cause of nerve injury in the case they present (ie, a compressed common peroneal nerve caused by posterior fibular head dysfunction), as well as their knowledge and abilities to apply OMT at the fibular head to alleviate the nerve compression. However, although the authors properly describe the patho anatomic condition of the patient, they do not address the pathophysiologic change that explains the remarkable and rapid resolution of muscle weakness in this case.1 It was obviously a case of motor conduction block, also known as neurapraxia.6 Neurapraxic lesions most commonly result from acute nerve compression, and “recovery is complete within days or weeks,” according to Oh.6 Oh6 also notes that it is important to recognize those cases that involve neurapraxia “because of the good prognostic implication” in such cases. A determination of neurapraxia can be obtained only with electrodiagnostic (EDX) testing, which is vital to rule out other causes of drop foot.7 These other causes commonly include L5 radiculopathy, lumbosacral plexopathy, motor neuron disease, and sciatic mononeuropathy.7 Wilbourn,8 who has written extensively on peroneal neuropathy, states, “The EMG [electromyographic] examination is a superb diagnostic study for the evaluation of foot-drop [ie, drop foot] in general and peroneal mononeuropathies in particular.” Wilbourn8 classifies the conduction block type of lesion as “Type 2.” This type of lesion is common, though it is not seen as often in the clinical setting as the “Type 1” pattern of mixed axon loss and conduction block.8 Wilbourn8 also notes that conduction block lesions have an “excellent prognosis” and rarely require surgical intervention. Typically, conduction block lesions do not become apparent (via EDX testing) until 7 to 10 days after the nerve becomes compressed.8 Therefore, it appears that Lavelle and McKeigue1 made a reasonable decision to avoid EDX testing in the case of their patient, who first noticed symptoms the day before visiting the primary care office. Many osteopathic physicians may believe that an immediate and rapid recovery as described by Lavelle and McKeigue1 is unlikely, and that the patient’s “recovery” may instead sugAs the premier scholarly publication of the osteopathic medical profession, JAOA— The Journal of the American Osteopathic Association encourages osteopathic physicians, faculty members and students at colleges of osteopathic medicine, and others within the healthcare professions to submit comments related to articles published in the JAOA and the mission of the osteopathic medical profession. 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