Use of ultrasound in detection and treatment of nerve compromise in a case of humeral lengthening.

The development of iatrogenic nerve lesions during and following limb lengthening procedures present a challenge to orthopedic surgeons. Early treatment of nerve damage is critical in salvaging full function of the nerve. Precise location of damage, however, must be determined in order to appropriately administer treatment. We report a patient with a short humerus caused by a growth arrest undergoing a 7-cm lengthening who developed a neurapraxic injury of the radial nerve. Nerve compromise was noted 1 month into the lengthening program. Nerve conduction studies and electromyography could not be used to determine the precise site of injury. Likewise, magnetic resonance imaging and computed tomography were contraindicated and inconclusive, respectively, due to the presence of a metallic external fixation device. High-resolution ultrasonography (US) findings, however, correlated with our clinical examination of the patient's radial nerve function and permitted identification of the precise site of nerve involvement. Treatment was administered by removing a causative half-pin. Several days following treatment, nerve function returned to normal. There are a limited number of articles in the literature regarding nerve injuries associated with limb lengthening and their corrective treatments. The outcome of this case underscores the usefulness of US over various other diagnostic techniques under certain circumstances.