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Biomedical subjects

Charles G Fisher

Publications and source records attributed to Charles G Fisher.

At least 19 recordsLinked to original sources
PubMed2006

Cost-effectiveness of surgery plus radiotherapy versus radiotherapy alone for metastatic epidural spinal cord compression.

PURPOSE: A recent randomized clinical trial has demonstrated that direct decompressive surgery plus radiotherapy was superior to radiotherapy alone for the treatment of metastatic epidural spinal cord compression. The current study compared the cost-effectiveness of the two approaches. METHODS AND MATERIALS: In the original clinical trial, clinical effectiveness was measured by ambulation and survival time until death. In this study, an incremental cost-effectiveness analysis was performed from a societal perspective. Costs related to treatment and posttreatment care were estimated and extended to the lifetime of the cohort. Weibull regression was applied to extrapolate outcomes in the presence of censored clinical effectiveness data. RESULTS: From a societal perspective, the baseline incremental cost-effectiveness ratio (ICER) was found to be $60 per additional day of ambulation (all costs in 2003 Canadian dollars). Using probabilistic sensitivity analysis, 50% of all generated ICERs were lower than $57, and 95% were lower than $242 per additional day of ambulation. This analysis had a 95% CI of -$72.74 to 309.44, meaning that this intervention ranged from a financial savings of $72.74 to a cost of $309.44 per additional day of ambulation. Using survival as the measure of effectiveness resulted in an ICER of $30,940 per life-year gained. CONCLUSIONS: We found strong evidence that treatment of metastatic epidural spinal cord compression with surgery in addition to radiotherapy is cost-effective both in terms of cost per additional day of ambulation, and cost per life-year gained.

Canada↗
PubMed2006

Impact of surgical intervention on quality of life in patients with spinal metastases.

STUDY DESIGN: Prospective clinical study. OBJECTIVE: To assess Health-Related Quality of Life outcomes in patients undergoing surgery for spinal metastases. SUMMARY OF BACKGROUND DATA: Increasing life expectancy of patients with spinal metastases has resulted in greater interest in overall quality of life, including pain and neurologic impairment. To assess the overall risks and benefits of surgical intervention, the overall impact of each on the overall health status must be assessed. METHODS: All patients who presented to a single institution with bony spinal metastases requiring surgical intervention were eligible. EXCLUSION CRITERIA: previous surgery for spinal metastases, primary tumors of the spine, and inability to fill out the questionnaires. Patients completed an EORTC QLQ-C30, the HUI-3, the EQ-5D, visual analog pain, and an ECOG functional assessment. at five points: before surgery and at 6 weeks, 3 months, 6 months, and 1 year post surgery. RESULTS: Of 96 patients who presented to the hospital, 85 were enrolled in the study. Average age was 58.6 years (range, 20.3-80.7 years) with 47 male patients; 50% survival as 39.1 weeks. Maximal and average VAS pain levels showed a statistically significant (P < 0.00001) improvement from preoperative to all postoperative time points. Only the QLQ-C30 global health status showed a statistically significant improvement from preoperative to the 6-week (P = 0.017), 3-month (P = 0.039), and 6-month (P = 0.013) time points. There was a statistically significant correlation between baseline global health status and survival time (P = 0.041). Overall distribution of HUI-3 utility calculated Quality of Life Adjusted Years (QALY) during the 1-year postoperative period showed a bimodal distribution with peaks at 0.1 and 0.7 years. CONCLUSIONS: Surgery for patients with spinal metastases offers decreased pain and improved quality of life with low rates of surgical complications.

Adult↗
PubMed2006

Progressive junctional kyphosis at the caudal end of lumbar instrumented fusion: etiology, predictors, and treatment.

STUDY DESIGN: Clinical case series. OBJECTIVE: To describe a series of patients with progressive sagittal decompensation caused by failure at the caudal end of an instrumented lumbar fusion. SUMMARY OF BACKGROUND DATA: Lumbar kyphosis in association with global sagittal decompensation can be a disabling problem, particularly as a late complication of distraction instrumentation. Although kyphosis at the rostral end of instrumented fusions secondary to adjacent segment degeneration has been well described, substantially less has been documented about failure and kyphosis at the caudal end. METHODS: Patients who have a progressive lumbar kyphosis and sagittal decompensation requiring operative revision were retrospectively reviewed, and radiographic measurements of lumbar lordosis and sagittal balance were performed to study this problem. RESULTS: There were 13 patients identified. The most common mode of caudal junctional decompensation was related to failure of the most distal fixation. Sagittal decompensation occurred even in the presence of satisfactory lumbar lordosis. Revision surgery and improved sagittal balance were achieved typically using the technique of pedicle subtraction osteotomy and extension of the instrumentation to the sacrum. Osteoporosis, hip osteoarthritis, and substance abuse were commonly observed associations. CONCLUSIONS: Fixation failure at the caudal end of lumbar-instrumented fusion should be considered in patients with progressive sagittal decompensation. The high potential for failure of L5 pedicle screws after the index surgery warrants serious consideration of extending such fusions into the sacrum/ilium.

Aged↗
PubMed2006

Changing face of spine trauma care in North America.

STUDY DESIGN: An evidence-based review and summary of literature from multiple disciplines involved in spine trauma. OBJECTIVES: To outline epidemiologic, clinical, and research issues influencing spine trauma in a longitudinal perspective. In addition, to provide guidance to clinicians and researchers to ensure that philosophies pertaining to the betterment of spine trauma care are understood and supported. SUMMARY OF BACKGROUND DATA: Epidemiologic data have provided insight into future demands the elderly patient with spine injury will place on the health care system. Regional trauma programs have emerged with further specialization resulting in regionalized spine trauma care. Evidence-based guidelines have streamlined imaging, and biomaterial advancements have facilitated the stabilization of the spinal column and decompression of the spinal cord. Promising experimental therapies promoting axonal regeneration and neuroprotective agents are beginning clinical trials, generating cautious optimism that effective therapies for spinal cord injuries will emerge. The unsustainable economics of increasing technology and patient expectations will make economic evaluation critical. METHODS: Evidence-based review of current literature and expert opinion. CONCLUSIONS: Multicenter spine trauma registries with patient-reported outcomes will allow many questions around spine trauma to be answered using the highest levels of evidence. This process in synergy with technical and biologic developments should ensure progress toward optimal care of the spine trauma patient. Future challenges will be to treat the breadth and magnitude of the discoveries within the fiscal restraints of the health care system and ensure its affordability for society.

Aged↗
PubMed2006

Confidence in spine training among senior neurosurgical and orthopedic residents.

STUDY DESIGN: A cross-sectional survey of senior neurosurgical and orthopedic residents. OBJECTIVE: To evaluate the confidence of senior orthopedic and neurosurgery residents in performing spinal surgical procedures and their need for further training. The content and exposure to spine training as well as anticipated practice profile were characterized. SUMMARY OF BACKGROUND DATA: Spinal surgery is performed by specialists with backgrounds in orthopedic surgery and neurosurgery. As this subspecialty evolves, the need to modify training programs to keep up with technological and medical advances becomes increasingly clear. The primary objective of this study was to evaluate the self-assessed confidence and perceived need for further training of senior orthopedic and neurosurgical residents in performing a number of spinal surgical procedures. METHODS: An evaluation of self-assessed surgical competence of senior orthopedic and neurosurgery residents in Canada was undertaken by mail-out questionnaire. A follow-up questionnaire was mailed to nonresponders 3 months later. Survey results were summarized using SPSS statistical software, and descriptive and comparative analyses were performed. RESULTS: Significant differences in time and exposure to spine training differentiated the neurosurgical and orthopedic residencies (37% and 16% of total residency time devoted to spine, respectively). Neurosurgical residents reported significantly higher levels of confidence for all 25 surgical procedures. Of those residents anticipating incorporating spine into their practice, 29% of neurosurgery residents planned on entering a spine fellowship compared with 17% of their orthopedic colleagues. CONCLUSIONS: Training in spine surgery constitutes a considerably larger proportion of neurosurgery residency than orthopedic residency. Neurosurgery residents graduate with significantly higher levels of confidence to perform spine surgery, while orthopedic residents report significantly higher need for additional training in spine surgery. The majority of neurosurgery graduates report that they will include spine in their clinical practice, while most orthopedic graduates will exclude it.

Cross-Sectional Studies↗
PubMed2006

Radiographic measurement parameters in thoracolumbar fractures: a systematic review and consensus statement of the spine trauma study group.

STUDY DESIGN: Systematic review. OBJECTIVES: To review the various radiographic parameters currently used to assess traumatic thoracolumbar injuries, emphasizing the validity and technique behind each one, to formulate evidence-based guidelines for a standardized radiographic method of assessment of these fractures. SUMMARY OF BACKGROUND DATA: The treatment of thoracolumbar fractures is guided by various radiographic measurement parameters. Unfortunately, for each group of parameters, there has usually been more than 1 proposed measurement technique, thus creating confusion when gathering data and reporting outcomes. Ultimately, this effect results in clinical decisions being based on nonstandardized, nonvalidated outcome measures. METHODS: Computerized bibliographic databases were searched up to January 2004 using key words and Medical Subject Headings on thoracolumbar spine trauma, radiographic parameters, and methodologic terms. Using strict inclusion criteria, 2 independent reviewers conducted study selection, data abstraction, and methodologic quality assessment. RESULTS: There were 18 original articles that ultimately constituted the basis for the review. Of radiographic measurement parameters, 3 major groups were identified, depicting the properties of the injured spinal column: sagittal alignment, vertebral body compression, and spinal canal dimensions, with 14 radiographic parameters reported to assess these properties. CONCLUSIONS: Based on a systematic review of the literature and expert opinion from an experienced group of spine trauma surgeons, it is recommended that the following radiographic parameters should be used routinely to assess thoracolumbar fractures: the Cobb angle, to assess sagittal alignment; vertebral body translation percentage, to express traumatic anterolisthesis; anterior vertebral body compression percentage, to assess vertebral body compression, the sagittal-to-transverse canal diameter ratio, and canal total cross-sectional area (measured or calculated); and the percent canal occlusion, to assess canal dimensions.

Consensus↗
PubMed2006

Intrarater and interrater reliability and validity in the assessment of the mechanism of injury and integrity of the posterior ligamentous complex: a novel injury severity scoring system for thoracolumbar injuries. Invited submission from the Joint Section Meeting On Disorders of the Spine and Peripheral Nerves, March 2005.

OBJECT: A new classification and treatment algorithm for thoracolumbar injuries was recently introduced by Vaccaro and colleagues in 2005. A thoracolumbar injury severity scale (TLISS) was proposed for grading and guiding treatment for these injuries. The scale is based on the following: 1) the mechanism of injury; 2) the integrity of the posterior ligamentous complex (PLC); and 3) the patient's neurological status. The reliability and validity of assessing injury mechanism and the integrity of the PLC was assessed. METHODS: Forty-eight spine surgeons, consisting of neurosurgeons and orthopedic surgeons, reviewed 56 clinical thoracolumbar injury case histories. Each was classified and scored to determine treatment recommendations according to a novel classification system. After 3 months the case histories were reordered and the physicians repeated the exercise. Validity of this classification was good among reviewers; the vast majority (> 90%) agreed with the system's treatment recommendations. Surgeons were unclear as to a cogent description of PLC disruption and fracture mechanism. CONCLUSIONS: The TLISS demonstrated acceptable reliability in terms of intra- and interobserver agreement on the algorithm's treatment recommendations. Replacing injury mechanism with a description of injury morphology and better definition of PLC injury will improve inter- and intraobserver reliability of this injury classification system.

Algorithms↗
PubMed2006

En bloc marginal excision of a multilevel cervical chordoma. Case report.

The purpose of this case report is to demonstrate that an en bloc resection with negative surgical margins can be successfully achieved in a case of a seemingly unresectable C-2 chordoma if appropriate preoperative staging and planning are performed. The management of chordomas is controversial and challenging because of their location and often large size at presentation. Because chordomas are malignant and will aggressively recur locally if intralesional resection is conducted, wide or true en bloc resection is generally recommended. The literature indicates, however, that surgeons are reluctant to perform wide or even marginal resections because of the lesion's complex surrounding anatomy and the risk of significant neurological compromise when a tumor abuts the dura mater or neural tissues. In this report the authors outline the successful en bloc resection of a large C1-3 chordoma and discuss the importance of preoperative staging and planning.

Biopsy, Needle↗
PubMed2006

Accuracy and safety of pedicle screw fixation in thoracic spine trauma.

OBJECT: The authors evaluated the accuracy of placement and safety of pedicle screws in the treatment of unstable thoracic spine fractures. METHODS: Patients with unstable fractures between T-1 and T-10, which had been treated with pedicle screw (PS) placement by one of five spine surgeons at a referral center were included in a prospective cohort study. Postoperative computed tomography scans were obtained using 3-mm axial cuts with sagittal reconstructions. Three independent reviewers (C.B., V.S., and D.G.) assessed PS position using a validated grading scale. Comparison of failure rates among cases grouped by selected baseline variables were performed using Pearson chi-square tests. Independent peri- and postoperative surveillance for local and general complications was performed to assess safety. Twenty-three patients with unstable thoracic fractures treated with 201 thoracic PSs were analyzed. Only PSs located between T-1 and T-12 were studied, with the majority of screws placed between T-5 and T-10. Of the 201 thoracic PSs, 133 (66.2%) were fully contained within the pedicle wall. The remaining 68 screws (33.8%) violated the pedicle wall. Of these, 36 (52.9%) were lateral, 27 (39.7%) were medial, and five (7.4%) were anterior perforations. No superior, inferior, anteromedial, or anterolateral perforations were found. When local anatomy and the clinical safety of screws were considered, 98.5% (198 of 201) of the screws were probably in an acceptable position. No baseline variables influenced the incidence of perforations. There were no adverse neurological, vascular, or visceral injuries detected intraoperatively or postoperatively. CONCLUSIONS: In the vast majority of cases, PSs can be placed in an acceptable and safe position by fellowship-trained spine surgeons when treating unstable thoracic spine fractures. However, an unacceptable screw position can occur.

Adolescent↗
PubMed2006

Subaxial cervical spine trauma.

Subaxial cervical spine injuries are common, ranging in severity from minor ligamentous strain or spinous process fracture to complete fracture-dislocation with bone and ligament failure, resulting in severe spinal cord injury. Understanding the epidemiology, anatomy, biomechanics, and classification of subaxial cervical spine injuries is important. Emergent management of such injuries is based on obtaining an accurate clinical history, careful physical examination, and organized radiographic evaluation. Attaining a unified approach to the wide spectrum of subaxial cervical injuries is difficult. In addition, controversy exists regarding the safety of closed reduction in certain injury patterns and the administration of methylprednisolone for acute spinal cord injury. Definitive management (surgical or nonsurgical) is based on the assessment of the mechanical instability of the injury, the presence or absence of neurologic impairment, and various patient factors that may influence outcome. Several complications, including the deterioration of neurologic status, may occur with either surgical or nonsurgical management, but the most frequent mistake made is missing the injury on initial evaluation.

Biomechanical Phenomena↗
PubMed2005

Factors predicting motor recovery and functional outcome after traumatic central cord syndrome: a long-term follow-up.

STUDY DESIGN: A prospectively maintained database-generated retrospective review and cross-sectional outcome analysis was performed at a single academic center. OBJECTIVES: To assess the improvement in ASIA motor score (AMS) and secondarily to assess generic health related quality of life (HRQoL) and functional status; correlating these with variables that may predict outcome. SUMMARY OF BACKGROUND DATA: Many variables are potential contributors to motor recovery, patient function, and outcome following cervical trauma. Studies often suffer from low power, short follow-up, heterogeneous cohorts, and use of outcome instruments that are neither valid nor psychometrically sound. METHODS: AMS were collected within 72 hours of the time of injury and again at follow-up by trained examiners. The SF-36 and FIM were administered to all patients at follow-up. RESULTS: AMS improved from a mean of 58.7 at injury to a mean of 92.3 at follow-up. Bowel and bladder continence was reported by 81% while independent ambulation was reported by 86%. Final AMS was positively correlated with the AMS at injury, formal education, and presence of spasticity at follow-up. Functional status (FIM) was positively correlated with higher AMS at injury, formal education, absence of comorbidities, absence of spasticity, and younger age. Generic HRQoL outcomes (SF-36) were improved in individuals with more formal education, fewer comorbidities, absence of spasticity, and anterior column fractures. CONCLUSIONS: Although the majority of patients improve to an AMS between 90 and 100, many have significant disability and are less functional than the general population. Significant predictive variables include the initial motor score, formal education, comorbidities, age at injury, and development of spasticity. An assessment of more than just the motor score is required to obtain an appreciation of the function and outcomes in this population.

Adult↗
PubMed2005

The effect of interbody cage positioning on lumbosacral vertebral endplate failure in compression.

STUDY DESIGN: A biomechanical investigation using a human cadaver, multisegmental lumbosacral spine model. OBJECTIVES: To determine if 2 small, posterolaterally positioned titanium mesh interbody cages would provide superior construct strength and stiffness in compression compared to central cage placement. In addition, determine construct stiffness with interbody cages as opposed to an intact spine and assess the effect of bone mineral density (BMD). SUMMARY OF BACKGROUND DATA: Previous work has shown that the posterolateral corners of the lumbosacral endplates are stronger than the anterior and central regions. Information to suggest appropriate interbody cage positioning to avoid subsidence into adjacent vertebrae would be valuable for spine surgeons and implant designers. METHODS: A total of 27 functional spinal units from L3 to S1 were dual x-ray absorptiometry scanned for BMD, instrumented with pedicle screw systems, and tested to failure in compression with titanium mesh interbody cages placed in 1 of 3 positions: 2 small posterolateral, 2 small central, or 1 large central. Analysis of covariance was conducted to compare failure load and stiffness across the different cage configurations. Repeated measures analysis of variance was used to analyze stiffness between functional spinal units with intact disc, discectomy, or interbody cages. Failure load was correlated against BMD. RESULTS: Of the 3 placement patterns, 2 small titanium mesh cages in the posterolateral corners had 20% higher failure loads, although the difference was not significant (P = 0.20). Stiffness in compression for the 3 cage positions was not significantly different (P = 0.82). All intact discs with posterior instrumentation were significantly stiffer than any of the cage patterns (P = 0.0001). BMD of the vertebrae significantly correlated with failure loads (P = 0.007). CONCLUSIONS: The placement of 2 small interbody cages posterolaterally tended to result in higher failure loads than central cage placement, although the results were not statistically significant. It is noteworthy that cage placement in any position resulted in a less stiff construct in compression than with an intact disc.

Aged↗
PubMed2005

Motor recovery, functional status, and health-related quality of life in patients with complete spinal cord injuries.

STUDY DESIGN: A retrospective cohort with cross- sectional follow-up. OBJECTIVES: The primary objective was to determine motor recovery in patients with complete traumatic spinal cord injury (SCI). Secondary objectives included: 1) determining which factors predict local recovery, 2) assessing functional status using the Functional Independence Measure (FIM), and 3) assessing generic health-related quality of life using the Short Form-36 (SF-36). SUMMARY OF BACKGROUND DATA: Motor recovery following complete SCI has been documented in the literature; however, it has been difficult to interpret: 1) spinal shock is often not addressed; 2) the definition of complete SCI has changed over the last 10 years; and 3) few studies differentiate between local neurologic recovery in the zone of partial preservation and neurologic recovery caudal to the lesion. METHODS: All patients admitted to Vancouver Hospital with a complete SCI between 1994 and 2001 were identified and included in the study if they remained complete following the resolution of spinal shock. Minimum 2-year follow-up consisted of an ASIA motor score, an FIM, and the SF-36. RESULTS: Of 133 patients identified, 94 were eligible and 70 completed follow-up. For the tetraplegic patients, the average ASIA motor score was 11.9 +/- 10.7 on admission and 20.1 +/- 10.8 at follow-up, a change reflecting local recovery only. For the paraplegic patients, the average ASIA motor score was 49.3 +/- 2.4 on admission and 50.6 +/- 1.7 at follow-up. CONCLUSIONS: Motor recovery does not occur below the zone of injury for patients with complete SCI. Varying degrees of local recovery can be expected in tetraplegic individuals.

Adolescent↗
PubMed2005

Strategies to promote neural repair and regeneration after spinal cord injury.

STUDY DESIGN: Retrospective review of current literature regarding neuroprotection and axonal regeneration therapies for acute spinal cord injury. OBJECTIVES: To provide an update for spine clinicians of the emerging therapeutic strategies for promoting neural repair and regeneration after spinal cord injury. SUMMARY OF BACKGROUND DATA: The neuroscientific community has generated a number of novel potential treatments for spinal injuries, some of which have entered clinical trials. Clinicians who manage spinal cord trauma are likely to encounter patients and their families who have questions or wish to be involved in these emerging treatments. METHODS: Literature review, with particular focus on currently used medications that may have neuroprotective potential in spinal cord injury, and axonal regeneration strategies that are emerging in preliminary human clinical trials. RESULTS: A number of medications such as erythropoietin and minocycline have demonstrated neuroprotective properties in animal models of spinal cord injury, and their long-established safety in humans make them appealing candidates for clinical trials. Human experience with novel neuroprotective and axonal regeneration strategies is growing around the world, and the peer-reviewed reporting of this is anxiously awaited. CONCLUSIONS: The initiation of human clinical trials for spinal cord-injured patients heralds great hope that effective therapies will be forthcoming, although a great deal remains to be learned. Clinicians must provide leadership in the epidemiologic design and rigor of these initial forays into human evaluation.

Animals↗
PubMed2005

The surgical management of primary tumorsof the spine: initial results of an ongoing prospective cohort study.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To prospectively validate the application of appendicular surgical oncology principles to the treatment of primary bone tumors of the spine at a quaternary care spine center using local recurrence, survival, and health-related quality of life as outcome measures. SUMMARY OF BACKGROUND DATA: There is clear evidence that violating the margins of a sarcoma or other malignancy during surgical resection will risk local recurrence and diminish overall survival. Previous publications have retrospectively demonstrated this oncologically sound approach to spine tumor management to be internally valid. The external validity or limited generalizability has not been assessed. METHODS: Included were all patients who underwent en bloc surgical resection of a primary tumor of the spine between January 1994 and November 2003, at the authors' institution. Patients were uniformly staged before surgery and baseline demographic and surgical variables were recorded, as well as a cross-sectional evaluation of generic health-related quality of life. RESULTS: Twenty-six patients (12 males and 14 females) were eligible for the study. Average age was 42 (range 16 to 70). There were 19 malignant tumors and 7 benign. There are 20 surviving patients with an average follow-up of 41.5 months (range 6 to 111 months), 15 of whom had malignant tumors. None of these patients have evidence of local recurrence, and one has evidence of systemic disease. The health-related quality of life, using the SF-36, shows acceptable morbidity of these procedures (physical component summary = 37.73 +/- 11.52, MCS = 51.69 +/- 9.54). CONCLUSIONS: Principles of wide surgical resection, commonly applied in appendicular oncology, can and should be used for the treatment of primary bone tumors of the spine with anticipated acceptable morbidity and satisfactory survival.

Adolescent↗
PubMed2005

Interbody device shape and size are important to strengthen the vertebra-implant interface.

STUDY DESIGN: An in vitro cadaveric study to compare compressive failure load, strength, and stiffness of the implant-vertebra interface. OBJECTIVES: To determine the effect of cage shape (kidney, cloverleaf, or oval) and cage surface area on endplate failure strength and secondly to determine the extent and pattern of trabecular failure adjacent to an interbody device. SUMMARY OF BACKGROUND DATA: Recent studies indicate that the posterolateral and peripheral regions of the endplate are stronger than the central. Current implants are not designed to take advantage of these stronger regions of the endplate. The zone of trabecular failure that results from interbody device subsidence has not been reported extensively in the literature. METHODS: Uniaxial compression testing with unrestricted rotation was carried out on the superior endplates of 48 thoracolumbar (T9-L2) vertebrae with 1 of 3 shaped indentors covering 20% or 40% of the endplate area. Failure load, failure strength, and stiffness were compared. Quantitative computed tomography scans were carried out before and following indentation tests to identify areas of trabecular densification that indicate localized failure. RESULTS: The cloverleaf-shaped indentors resulted in significantly higher (P < 0.001) failure loads (by >45%), strength (>49%), and construct stiffness (>35%) for both the 20% and 40% cross-sectional area sizes. Trabecular bone failure occurred in a semielliptical zone underlying the interbody devices, leaving the endplate and underlying cancellous bone intact. CONCLUSIONS: The cloverleaf-shaped indentor displayed an improved strength and stiffness profile when compared to oval or kidney-shaped indentors of similar surface areas.

Aged↗