Correlation of Magnetic Resonance Imaging (Neurography) and Electrodiagnostic Study Findings with Intraoperative Findings in Post Traumatic Brachial Plexus Palsy.

Background The majority of brachial plexus injuries (BPIs) are caused by trauma; most commonly due to two-wheeler road accidents. It is important to determine whether the lesion in question is pre-ganglionic or post-ganglionic for purposes of surgical planning and prognosis. Diagnostic testing helps the surgeon to not only decide whether surgical intervention is required, but also in planning the procedure, thereby maximizing the patient's chances of early return to function. The aim of the study was to determine the diagnostic efficacy of electrodiagnostic studies (Edx) and magnetic resonance imaging (MRI) individually, and in unison, in detecting the type and site of BPI by comparison with intraoperative findings (which were used as the reference standard) in patients with posttraumatic BPI. Methods It is an observational cross-sectional prospective randomized study, wherein 48 patients with BPI underwent a detailed clinical and neurological examination of the upper limb, Edx, MRI neurography and were subsequently operated upon. We assessed a total of 240 roots. The diagnosis of all spinal roots was noted on Edx. MRI was performed to look for root avulsion, pseudomeningocoele, and/or rupture injury. The patients were subsequently operated upon. All roots were traced from infraclavicular level right up to the foramen to ensure continuity of root or note rupture/ avulsion. The findings were tabulated. Results MRI accurately diagnosed 138 of the 147 injured roots and MRI sensitivity for the detection of BPI was 93.88%, whereas Edx correctly identified 146 out of 147 injured roots and thus, had sensitivity of 99.32%; however, both lacked specificity (18.28 and 20.43%, respectively). With Edx and MRI in unison, sensitivity was 100% which meant that if a given patient with a BPI is subjected to both tests, not a single abnormal root will go unnoticed. Conclusion Edx and MRI are two highly sensitive investigation modalities whose combined sensitivity is 100% for the detection of a root injury. Therefore, we recommend both tests as they are excellent screening tests.

Electrodiagnosis in traumatic brachial plexus injury.

Electrodiagnosis (EDX) is a useful test to accurately localize the site, determine the extent, identify the predominant pathophysiology, and objectively quantify the severity of brachial plexopathies. It can also be used to examine muscles not easily assessed clinically and recognize minimal defects. Post-operatively and on follow up studies, it is important for early detection of re-innervation. It can be used intra-operatively to assess conduction across a neuroma, which would help the surgeon to decide further course of action. Localization of the site of the lesion can be very challenging as there may be multiple sites of involvement and hence the electroneuromyographic evaluation must be adequate. The unaffected limb also needs to be examined for comparison. The final impression must be co-related with the type and severity of injury.

Relief from episodic weakness with pyridostigmine in paramyotonia congenita: a family study.

Pyridostigmine relieved episodic weakness in a family with paramyotonia congenita resulting from the R1448C mutation in the sodium channel gene. The transmission was autosomal dominant and the patients had paradoxical myotonia and exercise-induced weakness. On electrophysiological studies there were myotonic potentials, and there was progressive reduction of compound muscle action potential (CMAP) amplitudes after short exercise associated with clinical weakness. Pyridostigmine in doses of 60 mg three times daily abolished the drop in the postexercise CMAP amplitude and reduced the amplitude decrement to slow rate repetitive stimulation, but there continued to be a drop in amplitude on exposure to cold. The decline of the CMAP amplitude on exposure to cold was controlled by treatment with phenytoin. The clinical and electrophysiological features are discussed in relation to therapy with pyridostigmine and phenytoin.

Ulnar neuropathy at the elbow in diamond assorters.

Unilateral ulnar neuropathy at the elbow was detected in 12 men employed as diamond assorters. Asymptomatic diamond assorters were studied as controls. In the symptomatics, the ulnar neuropathy was restricted to the hand which held the eye-glass used for inspecting the diamonds. Electrophysiological studies using several parameters revealed neurapraxia sometimes combined with axonal degeneration in the ulnar nerve at the elbow, compatible with compression at that site. The most sensitive parameters of abnormality in the symptomatic subjects were segmental slowing of motor nerve conduction velocity across the elbow (P less than 0.001) and the amplitude of the compound muscle action potential obtained on stimulating the nerve above the elbow (P less than 0.001). In the 18 asymptomatic diamond assorters, electrophysiological studies revealed an ulnar neuropathy in two (again in the hand used for holding the eye-glass). Ulnar mononeuropathy at the elbow thus seems to be an occupational hazard for diamond assorters and it is worthwhile to elicit occupational history from patients presenting with an ulnar mononeuropathy, especially in Bombay and Gujarat where diamond industry is concentrated.