Assessment of conduction from C8 nerve root exit to supraclavicular fossa--its value in the diagnosis of thoracic outlet syndrome.

Conduction across the thoracic outlet in the components of the lower trunk of the brachial plexus was studied. With the recording electrode over the abductor digiti quinti latencies of stimulation in the supraclavicular fossa and of the C8 nerve root were ascertained. The difference between these 2 values reflected conduction time between C8 and the supraclavicular fossa. Four normal volunteers, 150 patients without Thoracic Outlet Syndrome and 50 patients with clinical thoracic outlet syndrome were studied. Using this method, conduction time from C8 to supraclavicular fossa ranged from 0.4 to 1.2 msec (mean = 0.6570, S.D. = 0.2097) in patients without thoracic outlet syndrome, and from 1.0 to 2.6 msec (mean = 1.7836, S.D. = 0.1984) in patients with thoracic outlet syndrome. These values show a significant difference between the 2 groups at the 0.05 level of confidence (T-Test). In thoracic outlet syndrome, conduction time has a tendency to be prolonged and the value above 1.3 msec is strongly suggestive of thoracic outlet syndrome. The values are consistent and reproducible. This method is easy to carry out and is a useful addition to the diagnostic assessment of thoracic outlet syndrome.

Selective sacral rootlet rhizotomy for hypertonic neurogenic bladder.

The authors describe a highly selective transsacral microsurgical procedure for sacral nerve rootlet interruption in five patients with hypertonic neurogenic bladder. Magnification and systematic stimulation of sacral roots provided accurate identification of motor fibers supplying bladder detrusor muscle and differentiation of efferent components to the legs and anal sphincter. Although the technique prevented incontinence and adverse effects of nerve section on rectal and lower extremity function improvement in voiding patterns and diminution of urinary sepsis was of brief duration in three of the five patients. Physiological data from these procedures reaffirms the importance of S-3 and S-4 motor roots in detrusor innervation, but clinical responses bring into question the possibility of sustained improvement from such a highly selective procedure at the sacral level. The authors suggest that alternative pathways, not apparent on initial stimulation, may develop after section of sacral root components, and that dissection and stimulation of fibers at the level of the conus medullaris should be investigated as an alternative procedure.