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T S Whitecloud

Publications and source records attributed to T S Whitecloud.

54 records · Page 3Linked to original sources
PubMed1986

Evaluation of hydroxylapatite graft materials in canine cervical spine fusions.

The efficacy of ceramic hydroxylapatite implant materials as graft materials for cervical spine fusion was evaluated in canines. Bioresorbable and non-bioresorbable systems were evaluated at time periods ranging from 1 to 24 weeks. Implant interbody position and progression of fusion were evaluated radiographically and histologically. Implant fracture and extrusion into adjacent soft tissues occurred in nine of 23 cases. Implant fracture occurred in many of the remaining 14 cases, however, the implant materials remained within the interspace. Implant fracture occurred with both implant systems. Radiographically little evidence of fusion was observed at less than 6 weeks, however by 12 weeks evidence of fusion was noted and was confirmed histologically. No difference in fusion rate or degree of fusion was observed between the two implant systems.

Animals↗
PubMed1986

Vibratory response in idiopathic scoliosis.

Recent clinical studies have suggested that a neurological lesion may be a cause of adolescent idiopathic scoliosis and animal experiments have implicated the posterior column pathway. We have tried to determine if differences in neurological response could be detected and measured clinically, and have compared the threshold of detection of vibratory sensation in 20 girls with adolescent idiopathic scoliosis with that in 20 clinically normal age-matched controls. A highly significant reduction of the threshold of detection of vibration was seen in the scoliotic group compared to the controls (p less than 0.001). Curve magnitude did not correlate with this threshold for either the upper (r = 0.172) or lower extremity (r = 0.126). Significant asymmetry between right- and left-sided thresholds to vibration was demonstrated in the scoliotic group. Our study supports the concept that an aberration in the function of the posterior column pathway of the cord may be of primary importance in the aetiology of idiopathic scoliosis. A clinically practical test to measure this function is presented.

Adolescent↗
PubMed1986

Upper extremity proprioception in idiopathic scoliosis.

Twenty-three patients with idiopathic scoliosis were tested for upper extremity proprioceptive function. All subjects had documented progression of deformity, with an average curvature of 34 degrees. The average ages for scoliotics and 18 control subjects were 16.1 and 20.8 years, respectively. Controls had no spinal deformity and underwent identical test procedures. The test results showed that scoliotic subjects had significant asymmetry between right and left limbs in their threshold for detection of joint motion (p less than or equal to 0.005) and in their ability to reproduce angles to which their elbow joint had been previously positioned (p less than or equal to 0.025). Slight asymmetry also was observed in the reproduction tests of the control group (p less than or equal to 0.013); however, there was no significant asymmetry seen in this group for the threshold test. Performance of bilateral limbs was designated good and bad for both groups; the limb that performed better in proprioceptive function was designated good limb. Analysis of data showed that the scoliotics' good and bad limbs performed inferiorly in both threshold and angle reproduction tests when compared with normal controls. The results of this study imply, but do not localize, a neurologic deficit in scoliotic patients.

Adolescent↗
PubMed1985

An analysis of failed Harrington rods.

Eight mechanically failed Harrington rods have been retrieved and examined clinically, metallurgically, and biomechanically to characterize the mode of instrument failure and to determine how future failure rates might be minimized. The results of the study indicated fatigue to be the mode of mechanical failure in all cases, however, in only one case was any significant metallurgical defect observed. Failure occurred at the ratchet-shaft junction in seven of eight cases with the remaining failure occurring at the midshaft region. This occurred in the rod with the metallurgical defect. The possibility of fatigue failure can be lowered by implementing both clinical and design considerations. Clinically, stress on the rod can be lowered by placing the ratchet-shaft junction as close to the hook as possible and by using the shortest rod possible. Both of these will minimize the moment arm at the vulnerable ratchet-shaft junction. Design modifications, including increased rod diameter, polishing the ratchet-shaft interface and material changes, can also be used to lower the stress on the rods and thus reduce the risk of mechanical failure.

Equipment Failure↗
PubMed1985

Chronic atlanto-axial instability in Down syndrome.

We studied the radiographs of thirty-two patients with Down syndrome for evidence of atlanto-axial instability. One of the patients had instability in 1970 and seven had it in 1983. The interval between the atlas and the odontoid process in the patients who demonstrated motion at that interval radiographically averaged 2.78 millimeters in 1970 and 6.93 millimeters in 1983 (p less than 0.005). Four patients whose radiographs showed atlanto-axial motion in 1970 lost that motion by 1983, and in seven patients who did not show atlanto-axial instability in 1970 it developed by 1983. Atlanto-axial instability was more likely to develop in boys who were more than ten years old. Accessory upper-cervical ossicles became evident in three patients, none of whom had atlanto-axial motion. However, one of these three patients had an abnormally wide atlanto-axial interval.

Age Factors↗
PubMed1984

Proprioception in idiopathic scoliosis.

Proprioception testing and gait analysis was performed on a group of 17 patients with idiopathic scoliosis. All curves had documented progression. The average curve was 26.8 degrees, all primary curves being right thoracic. The average age was 14.8 years. Twelve, healthy, age-matched controls underwent identical testing. Results showed that scoliotic subjects had asymmetry in their ability to reproduce angles between their two knees, as well as an absolute deficit in their ability to reproduce angles as compared with controls (P less than 0.01). The threshold of detection of change in angle at the knee was also quantitatively higher than controls (P less than 0.05), although asymmetry was not statistically significant. No significant differences were measured in gait parameters between scoliotics and controls. These joint position tests have been applied previously to young and elderly adults, athletes, and total joint patients. In no group has any asymmetry of response been demonstrated, both extremities showing virtually identical performance in each case. The tests administered measure sensory modalities, which are conducted through the posterior columns. Although the site of damage in the neural pathway cannot be specifically localized by these tests, results of this study support the presence of a neurologic deficit in idiopathic scoliosis.

Adolescent↗
PubMed1983

Segmental spinal instrumentation in the management of fractures of the thoracic and lumbar spine.

Eleven cases of fracture of the thoracic and lumbar spine were treated with segmental spinal instrumentation (Luque rods). The majority of these injuries occurred in motor vehicular accidents or falls from a height and were usually associated with multisystem trauma. This method of instrumentation provided immediate rigid internal fixation, which obviated the need for postoperative orthoses, allowed easier nursing care and early ambulation, and facilitated rehabilitation of patients with spinal cord injury. At 13 months' average follow-up, there have been no instances of wire breakage, rod deformation, or deterioration of neurologic status. This favorable experience suggests that segmental spinal instrumentation should be considered as an alternative mode of spinal instrumentation in fractures of the thoracic and lumbar spine.

Accidents, Traffic↗
PubMedDate not supplied

Magnetic resonance imaging of post-surgical pseudomeningocele.

Three cases of post-surgical pseudomeningocele (PSPM) are presented. MR imaging proved useful in diagnosing PSPM because, in the orthogonal planes, it demonstrated precisely the leakage site and the extent of the PSPM. MR imaging was also useful in demonstrating the presence of communication between the PSPM and the subarachnoid space.

Adult↗
PubMedDate not supplied

Lumbosacral fixation using expandable pedicle screws. an alternative in reoperation and osteoporosis.

BACKGROUND CONTEXT: Pedicle screw fixation in osteoporotic bone and in revision of previous pedicle screw fixation cases presents a significant challenge to spine surgeons. Biomechanical tests have shown that a pedicle screw that expands within the vertebrae body can substantially improve fixation in the presence of compromised bone. PURPOSE: To review the clinical and radiographic results with the use of expandable pedicle screws. STUDY DESIGN: One hundred forty-five patients received one or more expandable pedicle screws from the Omega21 spinal fixation system (EBI, L.P., Parsippany, NJ) to obtain thorocolumbar or lumbosacral stabilization. PATIENT SAMPLE: The indications for use of the expandable screws were osteoporosis (21 cases), reoperation of previous pedicle instrumentation (27 cases), intraoperative screw relocation (17 cases), construct reinforcement (23 cases), and sacral anchoring to avoid the necessity of anterior penetration of the sacral cortex (57 cases). OUTCOME MEASURES: The presence of radiographic fusion and complications arising from the instrumentation were reviewed at a mean follow-up period of 35 months (range, 24-72 months). METHODS: A retrospective clinical and radiographic review was performed. Fusion was evaluated based on anterior-posterior and lateral radiographs as well as dynamic radiographs in flexion and extension. RESULTS: Radiographic evidence of fusion was obtained in 125 of the 145 cases (86%). Eighty-six percent of patients with osteoporosis and 89% of reoperations fused. There were no instances of screw loosening or pullout of the expandable screws. Screw breakage occurred in four patients (2.8%), including three patients where fusion was not obtained. In six patients the expandable screws were removed without difficulty after fusion because of local discomfort. CONCLUSION: The results of this study have shown that expandable pedicle screws can be efficacious in cases in which pedicle screw fixation is difficult and adds a valuable tool to the growing armamentarium of spinal instrumentation.

Adult↗
PubMedDate not supplied

SF-36 health status of workers compensation cases with spinal disorders.

BACKGROUND CONTEXT: Poorer outcomes of treatment are reported in patients with spinal disorders who receive workers compensation. The reason for their suboptimal outcomes is unclear. No study has examined the relationship between workers compensation and the Short Form Health Survey (SF-36) health status of patients with spinal disorders. PURPOSE: To compare the self-perceived health status of spinal disorder patients receiving workers compensation with those not receiving workers compensation. STUDY DESIGN/SETTING: A cross-sectional study on 18,389 patients who were evaluated in the 28 centers comprising the National Spine Network. PATIENT SAMPLE: The study data were derived from patients when first evaluated for back or neck pain between January 1998 and April 2000. OUTCOME MEASURES: The outcome measures used were the eight individual and two component scores of the SF-36. METHODS: All first-visit patients enrolled in the National Spine Network from January 1998 to April 2000 were reviewed. Eight individual scores and two component scores of the SF-36 were compared. RESULTS: Of the 18,389 patients, 1,535 (8%) were receiving workers compensation. Bivariate analyses showed all eight individual scores, and two summary scores of the SF-36 were significantly lower (p<.0001) in patients receiving workers compensation. After controlling for confounding covariates, workers compensation status was a significant predictor of lower SF-36 scores for General Health (p<.0001), Physical Functioning (p<.0001), Role Physical (p<.01), Social Functioning (p<.05), and Mental Health (p<.05). CONCLUSIONS: Workers compensation status is associated with poorer physical and mental health of patients with spinal disorders. Because the workers compensation group is younger, has a shorter duration of symptoms, and fewer comorbid medical problems, the lower SF-36 scores most likely reflect psychological factors and not ill health per se. The lower SF-36 scores may also reflect premorbid personality differences in the workers compensation patients, compared with those not receiving workers compensation. SF-36 is a validated tool that can be used to objectively identify the patient at risk for delayed recovery. Future treatment protocols should pay special attention to improve the health-related quality of life, especially general health and physical functioning of spinal patients receiving workers compensation.

Adult↗
PubMedDate not supplied

Low-intensity pulsed ultrasound improves spinal fusion.

BACKGROUND CONTEXT: Increasing the incidence of solid bony fusion is a primary goal in spine surgery. Daily low-intensity pulsed ultrasound therapy has been shown to improve and accelerate the bone healing process. PURPOSE: The purpose of this study was to evaluate the efficacy of daily low-intensity pulsed ultrasound therapy to improve the rate and quality of spinal fusion. STUDY DESIGN: Canine fusion model prospective study. PATIENT SAMPLE: Fourteen adult male dogs were used. OUTCOME MEASURES: Radiographic grading of plain films, computed tomography (CT) and magnetic resonance imaging (MRI), gross palpation, torsional stiffness and histologic grading were used to determine the presence or absence of fusion. METHODS: Posterior noninstrumented bilateral fusions were evaluated at the L2-L3 and L5-L6 levels. Treatment with low-intensity pulsed ultrasound for 20 minutes per day over the fusion site (stimulated) was compared with fusion sites that received no stimulation (nontreated controls) at 6 and 12 weeks after surgery. Plain film radiographs, CT and MRI, mechanical torsion testing and histologic examination were performed. RESULTS: At 6 weeks, ultrasound treated sites were more frequently fused compared with nontreated controls, although the difference in fusion rate was not statistically significant. At 12 weeks after surgery complete radiographic and histologic fusion occurred in 100% of ultrasound-treated sites. In the nontreated control sites 78% had achieved complete radiographic fusion and 44% had complete histologic fusion. Compared with control sites, the histological and mechanical fusion rate was significantly greater in ultrasound-treated sites (P<.05) at 12 weeks. A statistically significant increase in mechanical stiffness in ultrasound-treated sites was also found at 12 weeks after surgery. CONCLUSIONS: Low-intensity pulsed ultrasound therapy may be a useful means to ensure successful spine fusion.

Analysis of Variance↗
PubMedDate not supplied

Trabecular bone mineral density in idiopathic scoliosis.

The association of idiopathic scoliosis with an osteoporotic state has been indicated previously. The present study compared the trabecular bone mineral densities of 44 adolescent idiopathic scoliotic girls with 44 age-, weight-, sex-, and race-matched controls. Their lumbar spine and femoral neck bone mineral densities were evaluated using dual-photon absorptiometry. Radiographs and scoliotic curve data were also obtained for the experimental group. The scoliotic subjects exhibited significantly lower lumbar and femoral neck bone mineral densities than the control subjects. No effect was found with respect to treatment, degree, or progression of curvature. The results of this study indicate that there is a generalized state of osteoporosis in idiopathic scoliotic girls when compared with matched controls.

Adolescent↗
PubMedDate not supplied

Vibratory hypersensitivity in idiopathic scoliosis.

This study determined whether a significant difference in response to vibratory stimuli was consistently present in a large group of children with idiopathic scoliosis as compared with age-matched controls. Fifty-eight unselected adolescent females with documented progressive idiopathic scoliosis were studied along with age-matched controls. Threshold to detection of a vibratory stimulus was measured in both the right and left upper and lower extremities. Results indicated that highly significant differences existed between scoliotic children and controls at all sites tested (p less than 0.01), with scoliotic children being more sensitive than controls. The results support the presence of a central aberration in posterior column function that may be a primary etiology of idiopathic scoliosis.

Adolescent↗
PubMedDate not supplied

Femoral neck and lumbar spine bone mineral densities in a normal population 3-20 years of age.

Dual-photon absorptiometry (DPA) with a 153gadolinium radionuclide source was used to measure bone mineral in the lumbar spine of 109 subjects and the femoral neck of 100 subjects 3-20 years of age. From the scan data collected, multiple linear regression models were developed to predict the measured bone mineral density values as a function of age, height, and weight; male and female data were evaluated separately. From the table of predicted values, a particular subject's bone mineral measurements can be readily compared with that of normal subjects in the same way "growth charts" are commonly used to assess development.

Absorptiometry, Photon↗
PubMedDate not supplied

Lumbar spine and femoral neck bone mineral density in idiopathic scoliosis: a follow-up study.

A follow-up study of the bone mineral densities (BMD) of 22 female subjects with idiopathic scoliosis was performed using dual-photon absorptiometry at an average follow-up period of 30.8 months. Compared to the initial scans, statistically significant increases in lumbar spine and femoral neck BMD were observed. When compared to normal subjects, approximately half of the scoliotic subjects were markedly osteoporotic, having BMD measurements at least two standard deviations below the expected value. Scoliotic curvature data could not be correlated with the BMD data. The observed osteoporosis is not transient and appears characteristic of idiopathic scoliosis.

Absorptiometry, Photon↗
PubMedDate not supplied

Stingers, the Torg ratio, and the cervical spine.

We prospectively determined the risk of initial stinger experience in a group of college football players while considering the presence of cervical canal stenosis and each player's position, playing time, and body type. Prospective analysis revealed a 7.7% incidence of initial stinger experience. The average Torg ratio for all players was 0.924 +/- 0.122, with the seventh cervical level being the narrowest. Initial stinger experience depended on position played and body type. The Torg ratio did not influence initial stinger occurrence. Players who experienced multiple stingers, however, had significantly smaller Torg ratios than players experiencing only one stinger (0.75 versus 0.87). A Torg ratio of 0.70 may be a more statistically and clinically appropriate threshold for determining significant cervical stenosis and advising collegiate athletes of their risk of experiencing recurrent stingers.

Case-Control Studies↗
PubMedDate not supplied

Vibratory response in congenital scoliosis.

Vibratory studies were performed on 10 adolescent subjects being followed for congenital scoliosis. The average age was 12 years 4 months and the average curve was 32 degrees. Twenty-one age-matched controls underwent identical studies. Threshold to detection of vibratory stimuli in the upper and lower extremities was quantified. Results showed that the scoliotic subjects were consistently less sensitive than the controls in the lower but not the upper extremity. The occurrence of hyposensitivity in only the lower extremity of persons with congenital scoliosis implies that the sensory deficit is secondary to the spinal deformity itself rather than a primary etiologic factor.

Adolescent↗