PracticeUpdate: Neurology - Winter 2018

ICNMD 2018 21

Ultrasonography Valuable in Confirmation of Carpal Tunnel Syndrome Ultrasonography is an effective, sensitive, and less expensive alternative to MRI to confirm carpal tunnel syndrome U ltrasonography has been found to be valuable for confirming carpal tunnel syndrome, suggest outcomes from two prospective studies reported at ICNMD 2018. and scaphoid bones parallel to each other (carpal tunnel inlet). Distal-to-proximal ratio was calculated 4 cm from the distal crease in the forearm. Nerve conductions were performed as per standard procedure. Magnetic resonance neurography axial and sagittal images employed a temporo- mandibular surface coil, fat saturation, and flow suppression.

cross-sectional area was 0.79 ± 0.13 cm 2 (0.59 to 0.11 cm 2 ) and 0.77 ± 0.1 cm 2 (0.53 to 0.1 cm 2 ) in the right and left median nerves, respectively. Mean cross-sectional area of participants was significantly higher than in controls. Nerve conduction studies in 27 participants revealed absent evoked motor response in four individuals (n=3 right, n=1 left). In 24 cases, mean distal motor latency and com- pound muscle action potential of the right median nerve was 5.8 ± 1.4 (4.2 to 11.4) s and 8.65 ± 3.0 (3.3 to 10.3) mV, respectively. On the left (26 cases), it was 5.5 ± 1.8 (3.3 to 10.3) s and 8.3 ± 3.7 (0.6 to 15.8) mV, respectively. Median nerve sensory nerve action poten- tials were absent in 16 participants (n=10 bilateral, n=4 right, n=2 left). Mean sensory latencies were 4.5 ± 2.4 (2.5 to 12) s and 3.4 ± 0.7 (2 to 4) s in the right (n=13) and left (n=14) sides, respectively. Corresponding mean sensory amplitudes were: Dr. Nalini noted, “Ultrasound of the nerves is an emerging, painless, easily accessible, affordable, and sensitive modality to study peripheral as well as proximal nerves to understand their involvement in carpal tun- nel syndrome. Particularly in this disorder, if we need objective follow-up assessment of any specific therapy, ultrasonography may be used repeatedly. These features of ultrasonography and its great utility in entrapment neuropathies prompted us to take up this study, also to obtain data in nor- mal controls for comparison and correlation. We plan to utilize ultrasonography to assess all our cases of carpal tunnel syndrome.” Dr. Nalini emphasized the importance of ultrasonography as a sensitive, cheaper, and effective alternate to MRI to confirm carpal tunnel syndrome. Cross-sectional area of the proximal median nerve may be used to predict severity of carpal tunnel syndrome. Moreover, mean and inlet cross-sectional area may be valid and easy-to-acquire parameters for routine clinical use in con- firming carpal tunnel syndrome. www.practiceupdate.com/c/70789 • Right 7.2 ± 5.3 (1.5 to 23) mV • Left: 9.9 ± 5.9 (2.3 to 22.1) mV Conduction velocities were: • Right 35.6 ± 11 (11.7 to 58) m/s • Left 43.7 ± 13 (22.2 to 68.6) m/s MRI in 19 individuals showed mean distal cross-sectional area of the right median nerve of 1.55 ± 0.49 (range 1 to 2.7) cm 2 and left median nerve, 1.57 ± 0.4 (range 1 to 2.7) cm 2 .

Among the eleven who recovered fully, only the first pattern of transcranial mag- netic stimulation (the presence of both cortical and spinal motor-evoked poten- tials) was registered. Those who recovered with sequelae exhibited the first or second pattern. In three participants who did not recover, only the third pattern was seen. Receiver operator curve analysis revealed significant correlation between long-term (3 to 5 years) recovery of the ability to walk in participants with consequences of mye- litis and a central motor conduction time ≥28.7 ms. In transverse myelitis, progressive loss of the fatty myelin sheath that surrounds the nerves in the affected spinal cord occurs for unclear reasons following infection or due to multiple sclerosis. A major theory posits that immune-medi- ated inflammation is present as the result of exposure to a viral antigen. Lesions are inflammatory and involve the spinal cord, typically on both sides. In acute transverse myelitis, onset is Ultrasonography was performed using the Philips Epiq 7G, linear 5 to 18Hz transducer. Median nerve cross-sectional area was recorded transversely at level of pisiform Atchayaram Nalini, MD, of the National Insti- tute of Mental Health and Neurosciences in Bengaluru, India, explained that carpal tunnel syndrome is the most common entrapment neuropathy (prevalence 3.8%). Ultrasono- graphic measurements are sufficiently accurate in the diagnosis of carpal tunnel syndrome, allow differential diagnosis, and support the surgeon. Dr. Nalini and colleagues compared the sensitivity of electrodiagnosis and high resolution nerve ultrasound in carpal tun- nel syndrome. “Some patients fear electrical stimulation and may be good candidates for examina- tion using ultrasonography,” Dr. Nalini told Elsevier’s PracticeUpdate .

sudden and progresses rapidly in hours and days. Lesions can be present any- where in the spinal cord, though they are usually restricted to only a small portion. Dr. Voitenkov explained that diagno- sis, and especially, prognosis, in acute transverse myelitis in children may be challenging. Dr. Voitenkov concluded that diagnos- tic transcranial magnetic stimulation was shown to detect neurophysiologic changes of acute transverse myelitis in 96% of cases and may be used as a pre- dictive tool. The absence of cortical and spinal motor- evoked potentials may be considered a sign of a highly probable poor clinical out- come of acute transverse myelitis. “Future directions,” Dr. Voitenkov noted, “may be the fusion of MRI and transcra- nial magnetic stimulation in the diagnostic process. In our opinion, the results of our study may probably be extrapolated to spinal processes of different origin, such as traumatic/neoplastic spinal injury.” www.practiceupdate.com/c/70413 A total of 30 participants were studied. Female to male ratio was 4:1. Mean age at presentation was 41.6 ± 10.5 (27 to 61) years. Clinically, 28 (93.3%) suffered from bilateral carpal tunnel syndrome (n=4 symmetrical, n=24 asymmetrical) and 2 exhibited uni- lateral involvement. The duration of illness varied from 2 months to 8 years. All participants voiced sensory complaints. A total of nine patients (30%) also suffered from motor deficits. Sensitivity of Tinel sign/Phalen’s maneuver was 40% and 63.3%, respectively. Using ultrasonogra- phy, cross-sectional area at the pisiform bone level was >0.1 cm 2 . In sex-matched controls (37 cases; 75 hands, n=39 female, n=6 male), mean distal

VOL. 3 • NO. 3 • 2018