Does superior-segment facet violation or laminectomy destabilize the adjacent level in lumbar transpedicular fixation? An in vitro human cadaveric assessment.

STUDY DESIGN: This is an in vitro biomechanical study. OBJECTIVE: The current investigation was performed to evaluate adjacent level kinematic change following unilateral and bilateral facet violation and laminectomy following 1-, 2-, and 3-level reconstruction. SUMMARY OF BACKGROUND DATA: The incidence of superior-segment facet violation with lumbar transpedicular fixation has been reported as high as 35%; however, its contribution to biomechanical instability at the supradjacent level is unknown. In addition, superior-segment laminectomy has been implicated as a risk factor for the development of adjacent level disease. The authors assess the acute biomechanical effects of proximal facet violation and subsequent laminectomy in an instrumented posterior fusion model in 10 cadaveric specimens. METHODS: Biomechanical testing was performed on 10 human cadaveric spines under axial rotation (AR), flexion-extension (FE), and lateral bending (LB) loading. After intact analysis, pedicle screws were inserted from L5-S1 and testing repeated with: (1) preserved L4-L5 facets, (2) unilateral facet breach, (3) bilateral breach, and (4) L5 laminectomy. Following biomechanical analysis, instrumentation was extended to L4, then L3 and biomechanical testing repeated. Full range of motion (ROM) at the proximal adjacent levels were recorded and normalized to intact (100%). RESULTS: Supradjacent level ROM was increased for all groups under all loading methods relative to intact (P < 0.05). However, AR testing revealed progressive instability at the adjacent level in groups 3 and 4, relative to group 1, following 1-, 2- and 3-level fixation (P < 0.05). During FE, supradjacent level ROM was significantly increased for group 4 specimens compared with group 1 after L5-S1 fixation (P < 0.05), and was greater than all other groups for L3-S1 constructs (P < 0.05). Interestingly, under lateral bending, facet joint destabilization did not change adjacent segment ROM. CONCLUSION: There were significant changes in proximal level ROM immediately after posterior stabilization. However, an additional increase in supradjacent segment ROM was recorded during AR after bilateral facet breach.Subsequent complete laminectomy at the uppermostfixation level further destabilized the supradjacent segment in FE and AR. Therefore, meticulous preservation of the cephalad-most segment facet joints-is paramount to ensure stability.

Outcomes of early surgical management versus late or no surgical intervention after acute spinal cord injury.

OBJECTIVE: To compare neurologic, medical, and functional outcomes of patients with acute spinal cord injury (SCI) undergoing early (<24 h and 24-72 h) and late (>72 h) surgical spine intervention versus those treated nonsurgically. DESIGN: Retrospective case series comparing outcomes by surgical and nonsurgical groups during acute care, rehabilitation, and at 1-year follow-up. SETTING: Multicenter National Spinal Cord Injury Database. PARTICIPANTS: Consecutive patients with acute, nonpenetrating, traumatic SCI from 1995 to 2000, admitted in the first 24 hours after injury. Surgical spinal intervention was likely secondary to nature of injury and the need for spinal stabilization. Interventions Not applicable. MAIN OUTCOME MEASURES: Changes in neurologic outcomes (motor and sensory levels, motor index score, American Spinal Injury Association [ASIA] Impairment Scale [AIS]), medical complications (pneumonia and atelectasis, deep vein thrombosis and pulmonary embolism, pressure ulcers, autonomic dysreflexia, rehospitalization), and functional outcomes (acute and rehabilitation length of stay [LOS], hospital charges, FIM instrument score, FIM motor efficiency scores). RESULTS: Subjects in the early surgery group were more likely ( P <.05) to be women, have paraplegia, and have SCI caused by motor vehicle collisions. The nonsurgical group was more likely ( P <.05) to have an older mean age and more incomplete injuries. ASIA motor index improvements (from admission to 1-y follow-up) were more likely ( P <.05) in the nonsurgical groups, as compared with the surgical groups. Those with late surgery had significantly ( P <.05) increased acute care and total LOS and hospital charges along with higher incidence of pneumonia and atelectasis. No differences between groups were found for changes in neurologic levels, AIS grade, or FIM motor efficiency. CONCLUSIONS: ASIA motor index improvements were noted in the nonsurgery group, though likely related to increased incompleteness of injuries within this group. Early versus late spinal surgery was associated with shorter LOS and reduced pulmonary complications, however, no differences in neurologic or functional improvements were noted between early or late surgical groups.

Innovative clinical path slashes back surgery LOS.

Cooperative in Seattle overcame professional resistance and a corporate reorganization on its way to implementing protocols that drastically cut LOS for lumbar laminectomy.

The assessment of appropriate indications for laminectomy.

We have developed criteria to determine the appropriate indications for lumbar laminectomy, using the standard procedure developed at the RAND corporation and the University of California at Los Angeles (RAND-UCLA). A panel of five surgeons and four physicians individually assessed 1000 hypothetical cases of sciatica, back pain only, symptoms of spinal stenosis, spondylolisthesis, miscellaneous indications or the need for repeat laminectomy. For the first round each member of the panel used a scale ranging from 1 (extremely inappropriate) to 9 (extremely appropriate). After discussion and condensation of the results into three categories laminectomy was considered appropriate in 11% of the 1000 theoretical scenarios, equivocal in 26% and inappropriate in 63%. There was some variation between the six categories of malalignment, but full agreement in 64% of the hypothetical cases. We applied these criteria retrospectively to the records of 196 patients who had had surgical treatment for herniated discs in one Swiss University hospital. We found that 48% of the operations were for appropriate indications, 29% for equivocal reasons and that 23% were inappropriate. The RAND-UCLA method is a feasible, useful and coherent approach to the study of the indications for laminectomy and related procedures, providing a number of important insights. Our conclusions now require validation by carefully designed prospective clinical trials, such as those which are used for new medical techniques.

Applying critical pathways to neurosurgery patients at the University of Michigan Medical Center.

UNLABELLED: Project Overview: In April 1990, The University of Michigan Hospitals began a major, multidisciplinary project to standardize care processes in order to increase efficiency and reduce costs while maintaining the quality of clinical care. A team of nurses began the project by developing critical pathways for two neurosurgery procedures--lumbar laminectomy and transphenoidal pituitary tumor resection. The pathways were reviewed by physicians and other staff from other disciplines and were implemented in January of 1991. KEY FINDINGS: Data from the first 14 months show a decrease in patients' average lengths of stay in both the intensive care unit (ICU) and routine care unit. Costs and variance data are being analyzed and further improvements to the pathways are being made. Eleven critical paths are now being used for neurosurgery patients. In retrospect, participants learned that physicians should be involved at the earliest stages of critical pathway development and in the process of implementation.