North American Spine Society 2000 presidential address.
Explore the source record for details and available documents.
Humans↗
Biomedical subjects
N Kahanovitz
Publications and source records attributed to N Kahanovitz.
The effect of varied electrical current densities on lumbar spinal fusions in dogs.
BACKGROUND CONTEXT: The use of electrical stimulation has been shown to increase the rate of successful spinal fusions. It is possible that increasing the current density of these stimulators may increase the speed and success rate of these fusions. PURPOSE: This study evaluated the effects of varied current densities on the speed and success rate of spinal fusion in dogs. STUDY DESIGN/SETTING: Three different current densities (0.83 microA/cm, 4 microA/cm and 10 microA/cm) were used to stimulate spinal fusions in a canine model over a 12-week period. OUTCOME MEASURES: Radiographic and histologic assessments were used to determine the degree of facet fusions at each time period. METHODS: Fifteen dogs underwent spinal facet fusion bilaterally at the level of L1-2 and L4-5. Each fusion site was electrically stimulated using one of three current densities. At 6, 9 and 12 weeks, the specimens were evaluated using high-resolution radiography and routine histology. The fusion masses were graded and then statistically evaluated. RESULTS: The results demonstrate a dose response of fusion mass scores to increasing current density. The highest current density (10 microA/cm) demonstrated a statistically higher fusion scores than the lowest currently density (0.83 microA/cm) at 6 weeks and statistically greater than both the middle (4 microA/cm) and lowest (0.83 microA/cm) current densities at 9 weeks. No differences were noted at 12 weeks, because all groups showed complete fusion. CONCLUSIONS: This controlled study suggests that speed of fusion may be further improved by increasing the current density of the electrical stimulation.
Animals↗
The role of scoliosis and pelvic obliquity on functional disability in myelomeningocele.
A retrospective analysis of 39 patients with myelomeningocele over age 16 was done to determine the effects of scoliosis and pelvic obliquity on their ambulatory ability and function. Although primarily dependent on neurologic level, prevention of an unbalanced spine and maintenance of ambulatory status also appeared to correlate closely with a curvature less than 40 degrees and a pelvic obliquity less than 25 degrees. All ambulators, regardless of neurologic level, had a pelvic obliquity of 25 degrees or less. Of the 19 ambulators, all but two had curvatures of 40 degrees or less. Ten of the 11 unbalanced sitters had a curvature of 35 degrees or more and a pelvic obliquity greater than 25 degrees. The quality of life style also appeared to correlate well with the severity of scoliosis and pelvic obliquity. Sixteen untreated patients with progressive curvatures prior to age 16 appeared to have insignificant curve progression past age 16. Twelve patients underwent posterior fusion in situ. This procedure alone is not recommended for the treatment of scoliosis associated with myelomeningocele because of the high morbidity.
Adolescent↗
The clinical spectrum of lumbar spine disease in achondroplasia.
A retrospective study was done to determine the entire clinical spectrum of lumbar spine disease in 47 adult patients, averaging 27.6 years of age, with achondroplasia. Five distinct clinical categories were defined. Twenty-eight percent of the patients were asymptomatic; 28% had only mechanical or degenerative lumbar pain; 6% had symptoms of a disc herniation; 21% had spinal claudication; and 17% had spinal claudication and objective neurologic deficits. Over 50% of the achondroplastic patients in this series had minor or no lumbar-spine-related symptoms through the third decade. The number of symptomatic patients did not increase in the older age groups. Ninety-one percent of symptomatic patients were 30 years of age or younger at the onset of symptoms. The presence of a thoracolumbar kyphosis, regardless of its magnitude, an L1 interpediculate distance less than 20 mm, and L5 interpediculate distance less than 16 mm, and a large structural lumbar lordosis were found more frequently in patients with disabling symptoms.
Achondroplasia↗
Congenital absence of the thoracic pedicle. A case report.
Explore the source record for details and available documents.
Child↗
Temperature effects on feline cortical and spinal evoked potentials.
To evaluate the effects of hypothermia on the somatosensory evoked potentials, baseline cortical and spinal evoked responses were obtained following induction of anesthesia at normal body temperature in five cats. The body temperature was lowered between 5 degrees and 6 degrees C and repeat cortical and spinal evoked responses were obtained. The cats were warmed to their original normal temperatures and the cortical and spinal evoked responses were repeated. After cooling the spinal evoked responses showed an average 40% increase in the latency (range 29-51%). Three of the animals showed a change in the normal waveform with the development of two distinct peaks instead of a single waveform. This was thought to be due to the varied vulnerability of the different cortical tracts to the lower temperature. Upon rewarming, the average latency returned to within 2.7% of the initial value, and the double waveform reunited to form a single wave. With cooling, the cortical evoked responses showed a similar consistent increase in latency. However, there was a much larger variability in the appearance of the waveforms. There was a range from an almost nonexistent wave in two cats to various waveform changes in the other cats. After rewarming there was a much slower return to normal latency in waveform than was found with the spinal evoked potentials. These experimental findings revealed an apparent deleterious, although reversible, effect on the somatosensory evoked potentials. Until the physiologic effects of cooling on the spinal cord are better understood, it is recommended that the temperature of patients undergoing spinal instrumentation be kept as close to normal as possible.
Animals↗
The comparative results of psychologic testing in scoliosis patients treated with electrical stimulation or bracing.
Proponents of the surface stimulation treatment of idiopathic scoliosis have reported approximately 75-85% success rates in arresting progressive curvatures. Although encouraging, these results do not appear to be better than those of the more traditional brace programs. Now recognizing electrical stimulation as a viable alternative to bracing, supporters have advocated the psychologic and physical freedom with electrical stimulation as a major advantage over brace treatment. However, to date, there have been no objective psychologic studies to substantiate these claims. This prospective study was devised to detect any significant differences between a group of patients treated in a TLSO or Milwaukee brace and a group of patients treated with lateral electrical surface stimulation (LESS) (ScoliTron). The study consisted of 40 female private patients with idiopathic scoliosis treated for a minimum of 3 months. Each patient was given a set of seven standardized psychologic tests and an observer rating by the treating physician or physical therapist working with the patient. Results of the Psychological Epidemiology Research Interview (PERI) revealed that the LESS group had significantly higher self esteem than the brace group. The brace patients demonstrated a much greater perception of directed hostility than the LESS group. The coping response inventory showed the brace group to manifest a more primitive coping mechanism than the LESS group. The brace group attempted to avoid problems associated with their disease, rather than cope with them as the LESS group was better able to do. The brace group focused more on their emotions than the realistic problems of their disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Adaptation, Psychological↗
The effect of discography on the canine intervertebral disc.
With increasing use of chemonucleolysis, interest and use of discography is at an all-time high. Various reports in past years have disagreed on the safety and efficacy of intradiscal injections of contrast mediums. This experimental study was devised to determine the effects of discography on the gross and histologic appearance of the lumbar intervertebral disc. Through a laparotomy approach, five lumbar discs in ten dogs were exposed. In each dog, one disc served as a control, another punctured with a needle, and the others injected with metrizamide, hypaque, or saline, At 2, 4, 6, 8, and 10 weeks postoperative, two dogs were killed at each time interval. Examination of the discs revealed no gross differences between any of the groups. The normal gross architecture of the concentric annulus and gelatinous nucleus was maintained in all specimens. This study found no evidence that discography results in gross or histologic damage to the intervertebral disc. It does not appear that discography will predispose a normal intervertebral disc to herniate. Discography alone appears to be a safe diagnostic procedure with no experimental evidence of any untoward gross or histologic effects.
Animals↗