Biomedical subjects
Publications and source records attributed to D G Kline.
A ten-year-old male was hospitalized for a pellet-gun wound to the brain. He developed Clostridial meningitis within eighteen hours in spite of radical debridement and prophylactic antibiotics. However, successful recovery was obtained with high levels of penicillin and chloromycetin antibiotic therapy.
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Lumbar, thoracic, and cervical spinal cord responses evoked by sciatic nerve stimulation were measured in 20 cats at the skin level and directly from the dorsal surface of the cord. Computer averaging techniques were used for both skin level recordings and cord surface recordings at all levels. Recordings made directly from the cord surface at lumbar levels were large and were characterized by a large, initial, negative transient, followed by a more complicated and variable waveform. As recording electrodes were moved rostrally, the initial large spike decreased in amplitude and the duration and latency of the response increased. At cervical levels were large and were characterized by a large, initial, negative transient, followed by a more complicated and variable waveform. As recording electrodes were moved rostrally, the initial large spike decreased in amplitude and the duration and latency of the response increased. At cervical levels the responses were polyphasic, of long duration and small amplitude. Deafferentation by posterior rhizotomy of all lumbar and sacral roots ipsilateral to sciatic nerve stimulation abolished the response at all levels. Thoracic cord section also abolished the response over the cervical cord. Skin level recordings were of shorter latency than direct recordings, especially at cervical levels. Response configurations were similar for both recording techniques at lumbar levels, but had different waveforms at both thoracic and cervical levels. Clinical implications of the techniques and possible explanations of the waveforms recorded are discussed.
Isometric measurements of muscle contraction in response to single as well as tetanic volleys of supramaximal stimuli were recorded from the limbs of 32 monkeys with noninjured or partially lacerated tibial nerves. Nerve action potentials (NAP) and muscle action potentials (MAP) were also determined at intervals varying from 1 hour to 52 weeks after injury. Limbs with mobilized noninjured nerve sustained small but definite decreases in muscle contraction strength particularly if the interval between operations was brief. Partially lacerated nerves had immediate averaged decreases in single twitch and supramaximal contraction strengths of 32.8% and 30.4% despite maintenance of NAP velocity. One week following injury, muscle contraction had decreased by another 21.6% and 19.7% respectively while NAP velocity was decreased by 18.5%. Measurements were also reduced at 2, 4, and 8 weeks and to a lesser degree at 12 weeks; at 24 and 36 weeks, muscle contraction was less than pre-injury data but not when compared to recordings 15 minutes after injury. Values recorded at 52 weeks reflected partial reinnervation of Achilles musculature. Studies over a 24-hour period following partial laceration demonstrated significant further decreases in muscle power by 8 hours. The authors conclude that nerve activity following partial laceration fluctuates as function diminishes during the early hours to weeks following injury.
Biopsies from partially lacerated nerves were taken at the sites of proximal stimulus, laceration, and distal recording, and from stimuli and recording sites of control nerves. Electron microscopic examination of the partially lacerated major fasciculus revealed three zones of injury. The laceration zone showed neurotemetic changes, the adjacent or intermediate zone, partial degeneration, and the zone most peripheral to the laceration, changes in ground substance. Progression of the original injury is apparently due to ongoing changes in the intermediate and peripheral zones while much of the relative early recovery is due to reversal of changes in these zones. Regeneration through the laceration of neurotemetic zone is limited but does account for a small amount of late recovery of function.
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Operative as well as electrophysiologic experience with 213 major nerve injuries over the last 8 years and primate experiments form the basis of this reappraisal. Those lesions in continuity resected (58 of 172) usually had no response to stimulation or nerve action potential (NAP) at 8 weeks or longer after injury but were not necessarily complete lesions on clinical examination or electromyography. Axonal organization and maturity were of such poor quality that functional regeneration would not have resulted. Despite preoperative evidence of an incomplete lesion, operative studies confirmed a complete lesion in 21 instances. In 103 lesions NAP's could be recorded and, where neurolysis was done, recovery was acceptable in 91 percent. Many of these lesions had appeared complete on preoperative evaluation. Nerves transected by glass and repaired primarily had superior electrical and functional recovery to those repaired secondarily, although variations in clinical settings prevented statistical analysis. Experimental work in 20 primates with glass-wounded nerves favored primary repair, for NAP, evoked muscle action potential, and strain gauge studies of muscle power were superior in 14. Lesions in continuity should have exploration delayed until 8 weeks so that physiologic decisions regarding need for resection and repair can be made. Transecting injuries should be explored primarily, those without contusinve element repaired immediately, and those with contusion repaired 3 weeks after injury.
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