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Biomedical subjects

C L Nash

Publications and source records attributed to C L Nash.

At least 19 recordsLinked to original sources
PubMed1991

Selection of lumbar fusion levels in adult idiopathic scoliosis patients.

Fifty-three adult idiopathic scoliosis patients whose fusions ended caudally between L2 and S1 were reviewed relative to criteria for selection of the lowest fused vertebra and their outcome. The Harrington stable zone, central sacral line, and the presence of rotary subluxation, arthritis, spondylolisthesis, vertebral body and disc space wedging were studied. Preoperative and postoperative pain, quality of life, and decisions for surgery were surveyed with a 94% response. Results showed the older the patient, the lower the fusion. The Harrington stable zone was useful, whereas the central sacral line frequently indicated longer fusions by as much as three segments. The presence of pathoanatomic features also dictated lower fusions. Patients in whom the lowest level of fusion was consistent with selection criteria had reduced frequency and intensity of low-back pain.

Adult↗
PubMed1989

Evaluation of the role of concave rib osteotomies in the correction of thoracic scoliosis.

The role of concave rib osteotomies was studied in a series of 25 patients with right thoracic idiopathic scoliosis who underwent Harrington distraction instrumentation and segmental sublaminar wiring of the thoracic curve. Group I had ten patients with rigid curves who had instrumentation, fusion, and segmental concave rib osteotomies. Group II had 15 patients with flexible curves who underwent instrumentation and fusion alone. Preoperative side bending curve reduction averaged 23% in Group I and 49% in Group II. Postoperative correction was similar in both groups with Group I achieving 60% (+/- 10%) overall correction and Group II, 57% (+/- 8%). Group I underwent 56% further reduction from side bending compared with Group II's 12% reduction. It was concluded that if preoperative side bending correction was below 35% of standing curve, curve correction comparable to flexible cases could be achieved through multiple concave rib osteotomies. Neurologic risk was not increased, but there was increased pulmonary morbidity of 30%.

Adolescent↗
PubMed1989

Decreasing homologous blood transfusion in spinal surgery by use of the cell saver and predeposited blood.

Blood loss and blood replacement are necessities in spinal surgery. They also have increasing risks. Three blood replacement options and combinations were investigated in patients undergoing major spinal deformity surgery. In Section 1, intraoperative replacement from harvested cell saver blood was investigated in 35 patients. This group averaged 40% (20-60%) return of the red cell mass lost intraoperatively. In Section 2, intraoperative replacement via predeposited autologous blood was investigated in 41 patients. The predeposited blood replaced 64% of the intraoperative red cell mass lost. In Section 3, ten single-stage and ten two-stage spinal surgery cases using both cell saver and autologous predeposited blood were investigated. With this program, 90% of the single-stage patients did not require additional homologous blood, while 80% of the two-stage patients did. In Section 4, 65 patients undergoing six general types of spinal surgery were examined to determine the number of predeposited autologous units needed to avoid homologous blood during hospitalization. Guidelines for determining optimal donation were developed assuming the use of intraoperative cell saver use.

Blood Banks↗
PubMed1989

The influence of contoured distraction rods on thoracic sagittal curves.

The influence of sagittally contoured rods on thoracic sagittal curves was studied in 19 patients who underwent fusion and instrumentation for right thoracic idiopathic scoliosis. Group I included 13 patients who underwent fusions with contoured rods and no releases. Group II included six patients who had anterior or posterior spinal release procedures in addition to contoured rods and fusion. Harrington distraction rods were contoured to either increase, decrease, or maintain preoperative thoracic kyphosis. The number of kyphotic curves that changed in the intended direction, the degree of change, the relationship of the rod contour to the patient's postoperative kyphosis, and the postoperative rod contour were compared. Thirty-eight percent of the curves in group I underwent change in the unintended direction while 62% of group I curves and 100% of group II curves changed in the intended direction. The curves that demonstrated intended change exhibited variability in the relationship of the postoperative kyphosis to the rod contour. In no case did the postoperative rod kyphosis exceed the measured intraoperative rod kyphosis.

Adolescent↗
PubMed1985

Segmental spinal instrumentation in idiopathic scoliosis. A preliminary report.

Eighty-six patients with idiopathic scoliosis who underwent a posterior spinal fusion using sublaminar segmental spinal instrumentation were analyzed retrospectively. There were two operative groups: group 1, 66 patients who had Harrington rod instrumentation and segmental wiring, and group 2, 20 patients who had Luque rod instrumentation. The clinical and radiographic data of the two groups were similar except for the passage of more sublaminar wires and increased intraoperative blood loss in group 2. Twenty intraoperative or postoperative complications occurred in 19 patients (22%) including 14 neurologic complications. Three patients (3%) had major spinal cord injuries, while 11 patients (13%) had transient sensory changes. There was no significant difference in the incidence of neurologic complications between group 1 or group 2. The remaining intraoperative complications were due either to anesthesia, positioning during surgery, or technique (dural tear). Late complications occurred in two patients in group 1 only: one each with rod breakage and hook displacement. Only one patient (1%) has required additional surgery. Our results indicate that although segmental instrumentation can be beneficial in idiopathic scoliosis, the incidence of complications, primarily neurologic, will be higher than expected. The major reason appears to be surgeon inexperience with passage of sublaminar wires. As experience increases, the incidence of complications declines and becomes comparable with conventional Harrington rod instrumentation alone.

Adolescent↗
PubMed1985

Idiopathic adolescent scoliosis--a prototype of degenerative joint disease. The relation of biomechanic factors to osteophyte formation.

A study was performed to evaluate the presence of degenerative joint disease (DJD) in idiopathic adolescent scoliosis (IAS) and correlate DJD with biomechanic factors. The average age of the subjects was 19 years (range, 12-30). Osteophytes reflecting the presence of degenerative joint disease occurred in apophyseal and/or intervertebral joints of 74% of 100 subjects. Osteophytes were correlated with curve angle and apical rotation. Compression forces are of pathogenic significance in the localization of osteophytes in IAS. IAS can serve as a naturally occurring prototype for the study of the influence of biomechanic factors on the pathogenesis of DJD.

Adolescent↗
PubMed1979

Risks of exposure to X-rays in patients undergoing long-term treatment for scoliosis.

Thirteen healthy teenage girls with idiopathic adolescent scoliosis were studied using multiple thermoluminescent dosimeters while undergoing standard diagnostic roentgenograms. Average organ doses for each anteroposterior and lateral examination were calculated for bone marrow, gastrointestinal tract, lungs, breast tissue, and gonads. Given an average of twenty-two roentgenograms over a three-year Milwaukee brace-treatment program, the increase in organ carcinogenic risk due to x-ray radiation ranged from 3.4 to fifteen per million (1.3 per cent to 7.5 per cent), except for breast tissue which increased from 140 to 290 per million (110 per cent). Using posteroanterior rather than anteroposterior exposures reduced the increased risk to 5.3 per million (3.8 per cent). The genetic risks of scoliosis roentgenographic studies were considered to be negligible, especially with gonadal shielding and infrequent roentgenograms made every three to four months. Good technique and judicious ordering of roentgenograms added significantly to the safety of the patient.

Bone Marrow↗
PubMed1977

Mutagenicity of the triazine herbicides atrazine, cyanazine, and simazine in Drosophila melanogaster.

Assays for dominant lethal mutations, sex-linked recessive lethal mutations, and chromosomal breakage, nondisjunction and loss were performed on Drosophila melanogaster males treated by injection or by larval feeding of the herbicides atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), cyanazine [2-chloro-4-(1-cyano-1-methylethylamino)-6-ethylamino-1,3,5-triazine], or simazine [2-chloro-4,6-bis-(ethylamino)-1,3,5-triazine]. The three herbicides significantly increased the rate of apparent dominant lethals, but this reduction in egg hatch was probably due to physiologic toxicity to sperm. Atrazine significantly increased X-linked recessive lethals and X or Y loss after treatment by larval feeding. Injection of simazine elevated X-linked lethals, whereas treatment by larval feeding did not. None of these herbicides significantly increased partial loss of the Y chromosome nor sex chromosome nondisjunction. Much larger experiments are needed to determine with confidence the mutagenic potential of these herbicides.

Animals↗