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.

Leprosy affects facial nerves at the main trunk: neurolysis can possibly avoid transfer procedures.

The predilective sites of lesions in leprous peripheral nerves are well established, and their surgical decompression is common practice when sensorimotor disorders persist after medication. By contrast, the precise localization of leprous facial neuropathy still remains unclear, and musculofascial transfers have been the only type of surgical treatment. The goal of this study was to clarify where leprosy affects facial nerves and to determine whether neurolysis might suffice to restore facial function. In five Indian and two Egyptian patients suffering from leprous facial neuritis, the nerves were stimulated transcranially at the brainstem to evoke efferent motor nerve action potentials, which were recorded from the exposed nerves. Lesions were detected at the main trunk proximally from the first bifurcation in all cases. Epineuriotomy revealed fibrosis of the interfascicular epineurium in all instances, as an indication for interfascicular neurolysis. One patient was able to close his eye and showed a better smile soon after surgery. After 16 and 21 months, respectively, one patient had improved distinctly, two patients slightly, two patients showing no progress, and two patients were lost to follow-up. It is concluded that (1) leprous facial neuropathy is located at the main trunk close to the first bifurcation and not exclusively at the peripheral zygomatic branches, (2) microsurgical neurolysis can be considered in leprous facial neuropathy before transfer procedures as long as voluntary or spontaneous activity is present in the affected muscles, and (3) intraoperative transcranial electrical stimulation is an effective means of localizing the site and proximal extent of leprous facial neuropathy.

Intraoperative electroneurodiagnostics to detect a second granuloma in the cubital area of median nerves affected by leprosy: a new approach to prevent incomplete surgery.

A recent work reports on the necessity to localize the most proximal site of leprous ulnar neuritis with intraoperative electroneurodiagnostics. In the present study we wanted to verify the applicability of this method on leprous median nerves. In six patients, seven median nerves were exposed at the wrist, all showing a typical leprous granuloma there. Spinal roots C5 to Th1 were then stimulated intraoperatively, evoking efferent mixed nerve compound action potentials (NCAPs) which were registered from the nerve's surface. No recordings could be obtained on the granuloma in all patients, neither distally nor shortly proximal from it, nor even further central at the forearm's proximal third where the median nerve exits the cubital area. Prior to dissecting the nerves in this precarious region, they were exposed at the arm's distal third, looking inconspicuous in all cases. Recordings could finally be obtained there, and subsequent exposure further proximal showed no increase in amplitude of the NCAPs, but there was a sharp decrease distally. In all cases, subsequent dissection of the cubital area revealed a second leprous granuloma extending variably from the distal third of the arm to the two heads of the pronator teres muscle, requiring microsurgical release. Intraoperative spinal root stimulation is an effective method to detect a second leprous granuloma and to avoid incomplete surgery in median nerves affected by leprosy.

The stapedial reflex in cephalic tetanus.

Three patients are presented with cephalic tetanus following injuries to the face. Two were adults and one a child. All three had bilateral VIIth cranial nerve involvement and one patient also presented with involvement of the IIIrd, IVth and VIth cranial nerves. The patients initially an ipsilateral VIIth cranial nerve weakness which later in the course of the illness developed into hyperactivity of the VIIth cranial nerve. The contralateral VIIth cranial nerve demonstrated a similar pattern. The stapedial reflex was tested serially. The stapedius muscle activity preceded that of the muscles of the face thus serving as an indicator of improvement or impending deterioration. Deflections measuring more than 1 cm, on stapedial reflex threshold testing, were indicative of stapedial reflex spasm. In the stapedial reflex decay test, both ill-sustained (intermittent) and sustained spasms of the stapedius muscle were seen.

Intraoperative spinal root stimulation to detect most proximal site of leprous ulnar neuritis.

In 10 patients with leprous ulnar neuritis, we investigated the most proximal site of lesion in the affected nerves. Spinal roots C8 and T1 were stimulated intraoperatively to evoke efferent mixed compound nerve action potentials which were recorded from the exposed ulnar nerves. The site at which amplitudes reached a maximum was considered the most proximal site of lesion. Nerve damage was found far proximally from the thickened segments in otherwise inconspicuous sections. Epineuriotomy within these apparently unaffected segments revealed fibrosis of the interfascicular epineurium in 9 patients, which is an indication for microsurgical interfascicular neurolysis.

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.

Simplified technique for recording human cortical & spinal evoked muscle potentials.

Muscle responses evoked on transcranial stimulation of the motor cortex (corticomotor) and motor roots (spinal) were studied in 20 healthy volunteers using a simplification of Rossini's technique and conventional EMG equipment. Cortical motor responses were consistently obtained from the contralateral upper limb with tolerable stimuli. Lower limb motor responses were inconsistent and sometimes required uncomfortably high stimulus strengths. In the upper limbs, peripheral conduction time (PCT) was estimated by the latency of the response to spinal stimulation. A comparable measure of PCT was obtained for the abductor pollicis brevis (APB) from the F-responses. The difference between the latency of the corticomotor response and the PCT was considered to represent central motor conduction time (CMCT). Corticomotor latencies were: APB 18.51 +/- 1.1 msec, biceps 9.77 +/- 0.46 msec and tibialis anterior 26.5 +/- 2.9 msec. CMCT from cortex to C8/T1 segments (APB) was 4.68 +/- 0.6 msec and between cortex and C5/C6 (biceps) 4.24 +/- 0.42 msec.