Biomedical subjects
J A McCulloch
Publications and source records attributed to J A McCulloch.
Effects of chymopapain on intervertebral disc and cartilage. (Ultrastructural study).
A direct ultrastructural study was carried out with a view to determining the changes brought about in vitro by chymopapain on the intervertebral disc and the vertebral growth plate. The tissues studied were: (A) fragments of protruded nucleus pulposus and extruded disc tissue; (B) portions of human and rabbit annulus fibrous; (C) fragments of rabbit vertebral growth plate. The fragments of tissue were incubated with chymopapain for three, six and twenty-four hours and were then fixed. In the protruded nucleus pulposus and extruded disc tissue, chymopapain produced disappearance of the electron-dense granules (which are presumably proteoglycans) and of the electron-dense granular material of the intercellular matrix. The enzyme probably also has an injurious action on the chondrocytes, but does not affect the fibrils and collagen fibres. Its action is also conditioned by the dimensions of the fragment of tissue incubated. If this is large, only the peripheral portion is completely digested. The action of the enzyme on the annulus fibrosus and the vertebral growth plate is similar to that on the nucleus pulposus. The present study indicates that the clinical effects of chymopapain are due to digestion of the proteoglycan granules and the electron-dense granular material of the herniated nucleus pulposus. These effects appear to be correlated with the collagen fibre content of the tissue, in the sense that the greater the collagen content, the more tissue mass remains unaffected.
Chemonucleolysis for relief of sciatica due to a herniated intervertebral disc.
Chemonucleolysis is the nonoperative chemical removal of displaced lumbar disc material. The enzyme chymopapain, which has a wide margin of safety between its effective therapeutic and toxic doses, is effective in the management of sciatica due to a herniated intervertebral disc. The patient will have leg pain as the dominant symptom and a 50% reduction in straight-leg raising with or without bowstring discomfort and crossover pain. Neurologic symptoms and signs are usual, as are abnormal results of contrast studies, which will verify the level of involvement. In 220 randomly selected patients who met criteria for the diagnosis of sciatica due to a herniated intervertebral disc and did not have psychogenic or nonorganic spinal pain, a spinal stenosis or a history of a previous, unsuccessful operation to relieve the sciatica, chemonucleolysis had a success rate of 80%. The only complications were a severe anaphylactic reaction in two patients and lesser, delayed reactions in five others. All of the reactions were successfully treated. Of the 45 patients in whom chemonucleolysis was unsuccessful, 38 underwent a laminectomy. In 3 of the 38 the results of chemonucleolysis were initially good, but later the disc herniation recurred; thus, the long-term treatment failure rate was 1.4%.
Variation of the lumbosacral myotomes with bony segmental anomalies.
Clinical localisation of a disc prolapse required dependable knowledge of the muscles supplied by the lumbosacral nerve roots. Localisation is most difficult in the 10 per cent of patients who have lumbosacral bony segmental anomalies. The lumbosacral plexus has been dissected in 11 cadavers with such anomalies and electrical stimulation studies carried out in 15 patients similarly afflicted. It is suggested that whatever the anomaly the "last fully mobile level" should be identified as the lowest level with a fully formed disc space, bilateral facet joints and two free transverse processes which do not articulate with the sacrum or pelvis. In three out of four patients with bony segmental anomalies the fifth lumbar root emerges at the last fully mobile level.
Failed lumbar disc surgery and repeat surgery following industrial injuries.
One hundred and seventy-nine of the compensation patients in this study who had one low-back operation had to have repeat back surgery. One hundred and three Workmen's Compensation Board patients who were reoperated on by a number of surgeons in the Toronto area were independently reviewed with one to two years of follow-up. Many had residual back pain, limited lumbar movement, presisting nerve-root deficits, and psychological disturbances. Forty per cent of the second operations were successful. Subsequent operations yielded progressively poorer results and made more patients worse than better. Operations were frequently undertaken without clear indications or evidence of correctable organic lesions. The results of repeat operations were better when the preceding operation had given more than six months' relief, when sciatica overshadowed back pain, and when a definite recurrent disc herniation was found. Scarring and neurolysis, previous infection, repair of a pseudarthrosis, and adverse psychological factors precluded a good result. Careful patient selection based on total evaluation of the disability including psychological assessment, accurate localization of the lesion by detailed investigation, and, most important, a logical sequence of decisions based on clear, objective criteria are prerequisites for this complex and demanding surgery. Caution and restraint are required when contemplating repeat back surgery.
Lateral lumbar discography.
The technique of lateral lumbar discography is described and compared with that of posterior lumbar discography. Its safety is demonstrated in a series of 1500 patients, only four of whom developed complications of note. Of these four, three developed discitis and one a retroperitoneal haemorrhage, all of which settled with conservative treatment.
Percutaneous radiofrequency lumbar rhizolysis (rhizotomy).
Low back pain may arise from degenerative changes in the posterior joints of the lumbar spine. These joints are innervated by a branch of the posterior primary ramus, which follows an anatomically constant course. Pain impulses from these joints can be interrupted by coagulating this nerve with a radiofrequency wave, the probe having been placed in the area of the nerve percutaneously. Percutaneous lumbar rhizolysis was carried out under local anesthesia on an outpatient basis in 82 patients, most of whom had multiple level rhizolysis. Rhizolysis was successful in 67% of patients with mechanical low back pain without evidence of disc herniation and nerve-root compression or psychogenic pain, who had not previously undergone an operation for relief of the pain.
Chemonucleolysis.
A prospective study of 480 patients who underwent enzymatic dissolution of the nucleus pulposus with chymopapain is reported. Seventy per cent of patients with the clincial criteria for a disc herniation had a favourable response to chemonucleolysis. The commonest cause of failure was persistent back pain. In patients with sequestered discs or lateral recess stenosis surgical intervention was not made more difficult by chemonucleolysis. Those with a previous operation, spinal stenosis or psychogenic components to the disability had very poor results. Complications were few and easily managed.
The effect of elantrine, a new anti-Parkinsonism agent, on drug-induced tremor in mice.
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Low-field-strength (open) MRI do not deliver the information needed to plan lumbar microdisectomy and/or microdecompression.
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Nonorganic physical signs in low-back pain.
Nonorganic physical signs in low-back pain are described and standardized in 350 North American and British patients. These nonorganic signs are distinguishable from the standard clinical signs of physical pathology and correlate with other psychological data. By helping to separate the physical from the nonorganic they clarify the assessment of purely physical pathologic conditions. It is suggested also that the nonorganic signs can be used as a simple clinical screen to help identify patients who require more detailed psychological assessment.
Outpatient chemonucleolysis.
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Percutaneous radiofrequency lumbar rhizolysis (rhizotomy).
Low-back pain may arise from degenerative changes in the posterior joints of the lumbar spine. These joints are innervated by a branch of the posterior primary ramus, which follows an antomically constant course. Pain impulses from these joints can be interrupted by coagulating the nerve with a radiofrequency wave, the probe having been placed in the area of the nerve percutaneously. Percutaneous lumbar rhizolysis was carried out under local anesthesia on an outpatient basis in 82 patients, most of whom had multiple level rhizolysis, Rhizolysis was successful in 67% of patients with mechanical low-back pain without evidence of disc herniation and nerve-root compression or psychogenic pain, who had not previously undergone an operation for relief of the pain.
Chemonucleolysis: experience with 2000 cases.
Chemonucleolysis is a safe, relatively minor procedure which can be done with the patient under local anesthesia. If the procedure is confined to patients with sciatica resulting from a herniated intervertebral disk, and patients with non-organic spinal pain, spinal stenosis and poor response to previous surgery are excluded, good results can be anticipated. It is important that the technique include proper placement of the needle and injection of adequate amounts of chymopapain into a disk space which is free of other materials. Chemonucleolysis is a good procedure to bridge the wide gulf between standard conservative treatment and surgery.