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Biomedical subjects

R J Hurlbert

Publications and source records attributed to R J Hurlbert.

At least 19 recordsLinked to original sources

Validating a newly proposed classification system for thoracolumbar spine trauma: looking to the future of the thoracolumbar injury classification and severity score.

BACKGROUND: Although numerous systems have been proposed, there is no universally accepted classification or scoring system for thoracolumbar spine injuries. Some have gained popularity, but most systems have never been modified or advanced beyond their initial introductory state. To the authors' knowledge, no thoracolumbar classification system has ever been validated in a systematic and scientific manner. STUDY PURPOSE: To critically review previous thoracolumbar classification systems, to discuss the proposal of the new Thoracolumbar Injury Classification and Severity Score (TLICS), to review the steps taken thus far in assessing the reliability of this system, and to discuss plans for future clinical validation of TLICS. METHODS: The authors performed a comprehensive search and analysis of previously published systems for classifying or scoring thoracolumbar spine injuries. Based on the merits and faults of these systems, among other factors, they have developed TLICS. CONCLUSIONS: Of the three phases of validating a fracture classification system described by Audige et al, TLICS has successfully passed through phase 1 (development) and phase 2 (multicenter agreement studies). With modifications made in response to phase 2 studies, TLICS will be ready to enter into the clinical validation phase. Although TLICS will initially be assessed for its ability to predict type of treatment, it is the authors' hope that, with appropriate analysis, the system will also be predictive of injury severity and clinical outcomes. These qualities remain to be demonstrated through rigorous prospective clinical investigation.

Humans↗

Why do you prescribe methylprednisolone for acute spinal cord injury? A Canadian perspective and a position statement.

OBJECTIVE: To determine the practice patterns for methylprednisolone administration for patients with acute spinal cord injury (SCI) within the spinal surgery community across Canada, and the reasons behind these patterns. METHODS: Canadian neurological and orthopedic spine surgeons were surveyed at their respective annual meetings with a questionnaire asking seven questions with respect to their practice standards. RESULTS: Sixty surgeons completed the survey representing approximately two-thirds of surgeons treating acute SCI within Canada. The NASCIS III dosing regimen is the most commonly prescribed steroid protocol. However, one-quarter of surgeons do not administer steroids at all. Of those who administer methylprednisolone, most do so because of peer pressure or out of fear of litigation. CONCLUSIONS: The vast majority of spine surgeons in Canada either do not prescribe methylprednisolone for acute SCI, or do so for what might be considered the wrong reasons. These results demonstrate the need for an evidence-based practice guideline. The Canadian Spine Society and the Canadian Neurosurgical Society fully endorse the recommendations of the steroid task force (see preceding paper).

Acute Disease↗

The role of steroids in acute spinal cord injury: an evidence-based analysis.

STUDY DESIGN: Literature review. OBJECTIVES: The purpose of this article is to review the available literature and formulate evidence-based recommendations for the use of methylprednisone in the setting of acute spinal cord injury (SCI). SUMMARY OF BACKGROUND DATA: Since the early 1990s, methylprednisolone has become widely prescribed for the treatment of acute SCI. Arguably, it has become a standard of care. METHODS: Through an electronic database search strategy and by cross-reference with published literature, appropriate clinical studies were identified. They were reviewed in chronologic order with respect to study design, outcome measures, results, and conclusions. RESULTS: Nine studies were identified that attempted to evaluate the role of steroids in nonpenetrating (blunt) spinal cord injury. Five of these were Class I clinical trials, and four were Class II studies. All of the studies failed to demonstrate improvement because of steroid administration in any of the a priori hypotheses testing. Although post hoc analyses were interesting, they failed to demonstrate consistent significant treatment effects. CONCLUSIONS: From an evidence-based approach, methylprednisolone cannot be recommended for routine use in acute nonpenetrating SCI. Prolonged administration of high-dose steroids (48 hours) may be harmful to the patient. Until more evidence is forthcoming, methylprednisolone should be considered to have investigational (unproven) status only.

Acute Disease↗

Intraoperative magnetic resonance imaging-augmented transoral resection of axial disease.

OBJECT: Because transoral decompression of the cervicomedullary junction is compromised by a narrow surgical corridor, the adequacy of decompression/resection may be difficult to determine. This is problematic as spinal hardware may obscure postoperative radiological assessment, or the patient may require reoperation. The authors report three patients in whom high-field intraoperative magnetic resonance (MR) images were acquired at various stages during the transoral resection of C-2 lesions causing craniocervical junction compression. METHODS: In all three patients the lesions involved the cervicomedullary junction: one case each of plasmacytoma and metastatic breast carcinoma involving the odontoid process and C-2 vertebral body, and one case of basilar invagination with a Chiari type I malformation. All three patients presented with progressive myelopathy. Surgery-planning MR imaging studies, performed after the induction of anesthesia, demonstrated the lesion and its relationship to the planned surgical corridor. Transoral exposure was achieved through placement of a Crockard retractor system. In one case the soft palate was divided. Interdissection MR imaging revealed that adequate decompression had been achieved in all cases. In the two patients with carcinoma, posterior instrumentation was placed to achieve spinal stabilization. Planned suboccipital decompression and fixation was averted in the third case because MR imaging demonstrated that excellent decompression had been achieved. CONCLUSIONS: Intraoperatively acquired MR images were instrumental in determining the adequacy of surgical decompression. In one patient the MR images changed the planned surgical procedure. Importantly, the acquisition of intraoperative MR images did not adversely affect operative time or neurosurgical techniques, including the instrumentation procedure.

Aged↗

Modified Brooks posterior wiring technique for three-point C1-C2 arthrodesis.

BACKGROUND: The optimal surgical treatment of atlanto-axial instability remains controversial despite the variety of modifications and supplemental techniques currently available. METHODS: We describe a modification of the Brooks posterior wiring technique supplemented with transarticular screws for C1-C2 instability. RESULTS: This method has been implemented in 30 patients in our institution with no radiological failures. CONCLUSIONS: The modification provides several technical advantages and potentially stronger fixation compared to methods currently in use.

Axis, Cervical Vertebra↗

Transoral resection of axial lesions augmented by intraoperative magnetic resonance imaging. Report of three cases.

Transoral decompression of the cervicomedullary junction may be compromised by a narrow corridor in which surgery is performed, and thus the adequacy of surgical decompression/resection may be difficult to determine. This is problematic as the presence of spinal instrumentation may obscure the accuracy of postoperative radiological assessment, or the patient may require reoperation. The authors describe three patients in whom high-field intraoperative magnetic resonance (MR) images were acquired at various stages during the transoral resection of C-2 disease that had caused craniocervical junction compression. All three patients harbored different lesions involving the cervicomedullary junction: one each of plasmacytoma and metastatic breast carcinoma involving the odontoid process and C-2 vertebral body, and basilar invagination with a Chiari I malformation. All patients presented with progressive myelopathy. Surgical planning MR imaging studies performed after the induction of anesthesia demonstrated the lesion and its relationship to the planned surgical corridor. Transoral exposure was achieved through placement of a Crockard retractor system. In one case the soft palate was divided. Interdissection MR imaging revealed that adequate decompression had been achieved in all cases. The two patients with carcinoma required placement of posterior instrumentation for stabilization. Planned suboccipital decompression and placement of instrumentation were averted in the third case as the intraoperative MR images demonstrated that excellent decompression had been achieved. Intraoperatively acquired MR images were instrumental in determining the adequacy of the decompressive surgery. In one of the three cases, examination of the images led the authors to change the planned surgical procedure. Importantly, the acquisition of intraoperative MR images did not adversely affect operating time or neurosurgical techniques, including instrumentation requirements.

Aged↗

A six year review of odontoid fractures: the emerging role of surgical intervention.

BACKGROUND: Traditionally, odontoid fractures have been treated with different bracing techniques resulting in variable degrees of successful healing. Surgical intervention is becoming more widely practiced as a primary intervention. The purpose of this report was to survey our recent experience in southern Alberta to determine potential outcome differences in management strategies. METHODS: We retrospectively reviewed the charts of 520 patients diagnosed with cervical spine fractures over a six-year period from January 1990, through December 1996. Patients were identified through the medical records database of the two Level 1 trauma facilities, on the basis of ICD-9 diagnostic coding. RESULTS: Ninety-three fractures of the odontoid process were identified, of which 85 were acute and eight were chronic. There were 57 Type II (67%) and 27 Type III (32%) acute odontoid fractures. Of these, 64 were managed conservatively (bracing), whereas 20 were treated surgically. Thirteen patients underwent anterior screw fixation, seven patients had posterior cervical fusion. Eleven patients died in the acute phase, two as a result of their high cervical cord injury and nine from unrelated medical causes. Fifty-six of the remaining 82 patients (68%) were located with a minimum of three months follow-up (range three months to eight years). Satisfactory results were obtained in 76% of all acute patients treated by bracing, but only 50% in those over the age of 65. In the surgically managed group, all patients (100%) went on to develop stable fusions. CONCLUSIONS: Our results indicate that while conservative management of odontoid fractures with external bracing results in fracture healing in most cases, surgical fusion may provide superior rates of bony union with acceptable morbidity. This difference in outcome lends itself to formal investigation through a prospective randomized trial.

Adolescent↗

Methylprednisolone for acute spinal cord injury: an inappropriate standard of care.

OBJECT: Since publication in 1990, results from the National Acute Spinal Cord Injury Study II (NASCIS II) trial have changed the way patients suffering an acute spinal cord injury (SCI) are treated. More recently, recommendations from NASCIS III are being adopted by institutions around the world. The purpose of this paper is to reevaluate carefully the results and conclusions of these studies to determine the role they should play in influencing decisions about care of the acutely spinal cord-injured patient. METHODS: Published results from NASCIS II and III were reviewed in the context of the original study design, including primary outcomes compared with post-hoc comparisons. Data were retroconverted from tabular form back to raw form to allow direct inspection of changes in treatment groups. These findings were further analyzed with respect to justification of practice standards. Although well-designed and well-executed, both NASCIS II and III failed to demonstrate improvement in primary outcome measures as a result of the administration of methylprednisolone. Post-hoc comparisons, although interesting, did not provide compelling data to establish a new standard of care in the treatment of patients with acute SCI. CONCLUSIONS: The use of methylprednisolone administration in the treatment of acute SCI is not proven as a standard of care, nor can it be considered a recommended treatment. Evidence of the drug's efficacy and impact is weak and may only represent random events. In the strictest sense, 24-hour administration of methylprednisolone must still be considered experimental for use in clinical SCI. Forty-eight-hour therapy is not recommended. These conclusions are important to consider in the design of future trials and in the medicolegal arena.

Acute Disease↗

Differential biomechanical effects of injury and wiring at C1-C2.

STUDY DESIGN: An in vitro study compared the biomechanics of the upper cervical spine among three groups of cadaveric specimens, each with a different source of instability: transverse-alar-apical ligament disruptions, odontoid fractures, or odontoidectomies. The responses of the three groups were again compared after a uniform posterior cable and graft fixation was applied to the specimens. OBJECTIVES: To quantify and compare the effects of different injuries on atlantoaxial stability and to determine whether a single fixation technique effectively treats each injury. SUMMARY OF BACKGROUND DATA: Previous biomechanical studies of atlantoaxial instability have been focused on mechanisms of injury or on comparison among fixation types. METHODS: Cables and pulleys applied torques to human cadaveric C0-C6 specimens quasistatically while an optical system tracked three-dimensional angular and translational motion at C0-C1 and C1-C2. Specimens were tested immediately after injury, after posterior cable and graft fixation, and after 6000 cycles of fatigue. RESULTS: Odontoidectomies increased C1-C2 angular and translational range of motion significantly more than odontoid fractures or ligament disruptions, especially during flexion-extension. Odontoid fractures produced a slightly larger increase in C1-C2 angular range of motion than ligament disruptions but a smaller increase in C0-C1 range of motion. The different injuries affected the lax zone and the position of C1-C2 axis of rotation differently. Restabilization by posterior cable and graft reduced motion only moderately for each injury type. All three fixated injuries were susceptible to loosening from fatigue. CONCLUSION: The three different injuries produce different spinal biomechanical responses. To best promote fusion, posterior cable and graft fixation should be used with an adjunctive stabilizing technique to treat all three injuries.

Adult↗

A biomechanical evaluation of occipitocervical instrumentation: screw compared with wire fixation.

OBJECT: The purpose of this study was to compare cable techniques used in occipitocervical fixation with two types of screw fixation. The authors hypothesized that screw fixation would provide superior immobilization compared with cable methods. METHODS: Ten cadaveric specimens were prepared for biomechanical analyses by using standard techniques. Angular and linear displacement data were recorded from the occiput to C-6 with infrared optical sensors after conditioning runs. Specimens underwent retesting after fatiguing. Six methods of fixation were analyzed: Steinmann pin with and without C-1 incorporation; Cotrel-Dubousett horseshoe with and without C-1 incorporation; Mayfield loop with C1-2 transarticular screw fixation; and a custom-designed occipitocervical transarticular screw-plate system. Sublaminar techniques were extended to include C-3 in the fusion construct, whereas transarticular techniques incorporated the occiput, C-1, and C-2 only. All methods of fixation provided significant immobilization in all specimens compared with the nonconstrained destabilized state. Despite incorporation of an additional vertebral segment, sublaminar techniques performed worse as a function of applied load than screw fixation techniques. Following fatiguing, these differences were more pronounced. The sublaminar techniques failed most prominently in flexion-extension and in axial rotation. On gross inspection, increased angular displacement associated with loosening of the sublaminar cables was observed. CONCLUSION: Occipitocervical fixation can be performed using a variety of techniques; all bestow significant immobilization compared with the destabilized spine. All methods tested in this study were susceptible to fatigue and loss of reduction and were weakest in resisting vertical settling. Screw fixation of the occiput-C2 reduces the number of vertebral segments that are necessary to incorporate into the fusion construct while providing superior immobilization and resistance to fatigue and vertical settling compared with sublaminar methods.

Analysis of Variance↗

A prospective randomized double-blind controlled trial to evaluate the efficacy of an analgesic epidural paste following lumbar decompressive surgery.

OBJECT: Pain control can often be improved by local (as opposed to systemic) application of analgesic and/or anesthetic medication. The purpose of this study was to evaluate the efficacy of a single-dose epidural analgesic "paste" in the control of postoperative pain in patients who have undergone lumbar decompressive surgery. METHODS: Sixty patients undergoing routine elective lumbar decompressive surgery were randomized in a double-blind fashion to one of two groups: those receiving active paste or placebo paste. The paste was applied to the exposed dura at the time of surgery, just prior to wound closure. Patients received follow-up care in the hospital and at home for 3 months postsurgery. Several outcome measures were studied to ascertain differences in pain control and to ensure comparability between groups. Patients who received active paste demonstrated significantly lower pain scores compared with those who received placebo paste for up to 6 weeks postoperatively. General health perception indexed by the Short Form 36 was also significantly better in patients who received active paste for up to 6 weeks. In-hospital and outpatient oral narcotic consumption was significantly lower in the active paste-treated group. Inpatient straight leg raising scores were improved in those patients who received active compared with control paste. CONCLUSIONS: Application of an analgesic paste directly to the epidural space during lumbar decompressive surgery significantly improves postoperative pain control, reduces prescribed analgesic drug consumption, and improves overall health perception for up to 6 weeks following surgery. The authors conclude that this postoperative pain control strategy is both effective and safe and may provide a new standard of pain management in patients undergoing lumbar discectomy or laminectomy.

Analgesia, Epidural↗

A surgically placed epidural catheter in a patient with spinal trauma.

PURPOSE: To report the successful perioperative anaesthetic and analgesic management of a spinal trauma patient with a surgically placed epidural catheter. CLINICAL FEATURES: A 15-yr-old adolescent woman sustained an unstable spinal column injury with an incomplete neurological deficit following a high speed motor vehicle accident. She was scheduled for spinal decompression and stabilisation through a left thoracoabdominal approach. Balanced general anaesthesia was undertaken. Prior to closure, a multi-orifice epidural catheter was surgically placed under direct vision 5 cm into the anterior epidural space. The catheter was then tunnelled out through the psoas muscle and secured in place. Combined epidural-general anaesthesia was then initiated for the duration of the case using 5 ml bupivacaine 0.25% after an initial test dose of 3 ml lidocaine 1.5% with epinephrine. An infusion of bupivacaine 0.10% and fentanyl 5 micrograms.ml-1 at 8 ml.hr-1 using patient controlled epidural analgesia (PCEA) provided excellent postoperative pain control for four days. She had an uncomplicated postoperative course. CONCLUSION: A surgically placed epidural catheter provided excellent, safe, perioperative anaesthesia and analgesia in this patient with unstable spinal trauma.

Accidents, Traffic↗

Ninety-degree rotation of the thoracic spinal thecal sac. Case report.

This 44-year-old man presented with a 4-year history of progressive spastic weakness of his legs. He was found to have epidural lipomatosis behind the thoracic spinal cord, and the nerve roots exited from the posterior and anterior midline planes of the dura, indicating a 90 degree rotation of the thoracic cord. Magnetic resonance images clearly demonstrated the segmental thoracic nerve roots exiting from the dorsal midline of the dura, a finding confirmed at surgery. The authors found only one previously published case of rotation of the spinal cord. Directed mechanical stress caused by deformation of the rotated spinal cord, rather than compression from adipose tissue, is proposed as the mechanism of the myelopathy. The extent, location, and thickness of the associated extradural adipose tissue is suggestive of epidural lipomatosis. The lipomatous tissue might have been an epiphenomenon and cord rotation an isolated congenital anomaly. Alternatively, asymmetrical growth of epidural fat may have exerted torque, rotating the thecal sac.

Adipose Tissue↗