No abstract

Purpose. To determine the prevalence of constipation-related symptoms in individuals with chronic spinal cord injury (SCI), to describe the bowel program as reported by patients and including use of bowel medications and evacuation techniques, and to examine the clinical, functional and pharmacological risks of di culty with evacuation. Patients and Methods. This is a cross-sectional study of all in-patients at least 3 months beyond acute injury, on the West Roxbury/Brockton VAMC SCI Service, during a 10 month period (n=197). Clinical, functional, and medication data were abstracted from medical and nursing records. Individual interviews were conducted with all available participants (n=161, 82%) regarding bowelrelated symptoms and treatment over the previous 1 month period. The study de®nition of di culty with evacuation was spending more than 1 h per episode of bowel evacuation. Results. Forty-one percent of the 161 interview responders spent more than 1 h on bowel evacuation, 50% reported abdominal distension and 38% reported abdominal pain, 27% reported headaches or sweats relieved by having a bowel movement, and 33% reported fecal incontinence at least once a month. The bisacodyl suppository was the most commonly used laxative agent, while docusate was the most popular oral agent. Subjects with di culty with evacuation (n=66) were compared with those who spent less than 1 h on evacuation (n=95). Factors associated with di culty with evacuation were tetraplegia, Frankel grade A/B, laxative use, polypharmacy, previous urinary outlet surgery, and symptoms of abdominal pain and distension. Conclusion. Constipation-related symptoms are highly prevalent in individuals with spinal cord injury, despite considerable laxative use. Our ®ndings suggest that di culty with evacuation can be predicted on the basis of a patient's clinical pro®le.

We measured lung and chest wall compliance as well as rib cage and abdominal dimensions in the supine position in five acute C4-7 quadriplegics. Studies were performed serially from 1 to 12 months after injury. Results were compared with those of control groups of chronic (greater than 1 yr after injury) quadriplegics and normal volunteers. We found that lung compliance was lower in acute and chronic quadriplegics (0.129 +/- 0.023 and 0.176 +/- 0.043 L/mm Hg, respectively) than in normal subjects (0.278 +/- 0.086 L/mm Hg) and that these changes apparently occurred within 1 month of injury. Specific lung compliance appeared to be reduced to a lesser degree, suggesting that the changes in lung compliance were partly due to reduced lung volumes and partly to altered mechanical properties of the lung. During respiratory maneuvers, abdomen and rib cage dimensional changes demonstrated rib cage distortion. This distortion was less severe in chronic than in acute quadriplegics. The improvement in chest wall stability was likely due to increased strength of cervical accessory muscles of respiration and improved coupling of the various rib cage elements in chronic quadriplegics.

Previous studies suggest that abdominal binding may affect the interaction of the rib cage and the diaphragm over the tidal range of breathing in quadriplegia. To determine whether abdominal binding influences rib cage motion over the entire range of inspiratory capacity, we used spirometry and the helium-dilution technique to measure functional residual capacity (FRC), inspiratory capacity, and total lung capacity (TLC) in eight quadriplegic and five normal subjects in supine, tilted (37 degrees), and seated positions. Combined data in all three positions indicated that, with abdominal binding, FRC and TLC decreased in normal subjects [delta FRC = -0.33 + 0.151 (SD) P less than 0.01); delta TLC = -0.16 + 0.121, P less than 0.05]. In quadriplegia there was also a reduction in FRC with binding (delta FRC = -0.32 + 0.101, P less than 0.001). However, TLC increased in quadriplegia (delta TLC = 0.07 + 0.061, P less than 0.025). In an additional six quadriplegic and five normal subjects, we used magnetometers to define the influences of abdominal binding on rib cage dimensions and TLC. In quadriplegia, rib cage dimensions were increased at TLC with abdominal binding, whereas there was no change in normals. Our data suggest that this inspiratory effect of abdominal binding on augmenting rib cage volume in quadriplegia is greater than the effect of impeding diaphragm descent, and thus abdominal binding produces a net increase in TLC in quadriplegia.

Mechanisms underlying the development of spasticity after spinal cord injury are not understood. One spinal interneuron likely to be affected is the Renshaw cell, which acts to produce recurrent inhibition in motor neurons as well as inhibiting Ia interneurons. Descending pathways exert both excitatory and inhibitory control over Renshaw cell activity. We studied Renshaw cell activity in normal subjects and in patients with varying levels of spasticity after spinal cord injury using the conditioned H-reflex technique of Pierrot-Deseilligny and Bussel. A submaximal stimulus to the tibial nerve is presented prior to a supramaximal stimulus so that action potential collision permits an H reflex (H') to be elicited in response to the supramaximal stimulus. The amplitude of this H' reflex is affected by activity in recurrent inhibitory pathways. Patients with both complete and partial spinal cord lesions were studied; date of injury ranged from 1 month to 216 months prior to evaluation. In the 18 patients in whom H reflexes could be recorded, H' reflexes were absent in 13, in contrast to their uniform presence in normal subjects. We conclude that recurrent inhibition via Renshaw cell activity is increased in spinal cord injury, and that measures of recurrent inhibition may correlate well with some clinical measures of spasticity.