RESUMEN

STUDY DESIGN: A prospective, observational study. OBJECTIVES: To identify outcome predictors of surgery for degenerative lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: Degenerative lumbar spinal stenosis is the most frequent indication for spine surgery in the elderly. More than 25% of surgical patients have a poor outcome, yet little is known about factors that predict the outcome of surgery. METHODS: Surgery was performed on 199 patients with degenerative lumbar spinal stenosis, and they were observed for 2 years after surgery in four referral centers. Surgery consisted of decompressive laminectomy with or without arthrodesis. Outcomes included validated measures of symptom severity, walking capacity, and satisfaction with the results of surgery. Potential predictors of outcome included sociodemographic factors and physical examination, as well as radiographic, psychological, social, and clinical history variables. RESULTS: The proportion of patients with severe pain decreased from 81% before surgery to 31% by 2 years afterward. The most powerful preoperation predictor of greater walking capacity, milder symptoms, and greater satisfaction was the patient's report of good or excellent health before surgery. Low cardiovascular comorbidity also predicted a favorable outcome. CONCLUSIONS: Patient's assessments of their own health and comorbidity are the most cogent outcome predictors of surgery for spinal stenosis.

Asunto(s)

RESUMEN

STUDY DESIGN: An animal model of posterolateral intertransverse process lumbar spinal fusion using autologous bone, coralline hydroxyapatite, and/or direct current electrical stimulation. OBJECTIVES: To evaluate the effect of an osteoconductive bone graft substitute and direct-current electrical stimulation on the rate of pseudarthrosis in a rabbit spinal fusion model. SUMMARY OF BACKGROUND DATA: Conventional techniques for the surgical treatment of degenerative conditions in the lumbar spine have a substantial failure rate and associated morbidity. Bone graft substitutes and electrical stimulation are alternative techniques to enhance fusion rates and limit the morbidity associated with posterolateral intertransverse process fusion using autologous iliac crest bone graft. METHODS: Fifty-three adult female New Zealand White rabbits underwent single-level lumbar posterolateral intertransverse process fusion. Animals were assigned to one of four groups using either autologous bone (Group I), coralline hydroxyapatite with autologous bone marrow aspirate (Group II), coralline hydroxyapatite with a 40-microA implantable direct current electrical stimulator and bone marrow aspirate (Group III), or coralline hydroxyapatite with a 100-microA implantable direct current electrical stimulator and bone marrow aspirate (Group IV). Animals were killed at 8 weeks, and fused motion segments were subjected to manual palpation, mechanical testing, and radiographic and histologic analysis to assess the fusion mass. RESULTS: Successful fusion was achieved in 57% (8/14) of animals in Group I, 25% (3/12) in Group II, 50% (6/12) in Group III, and 87% (13/15) in Group IV. Mean stiffness and ultimate load to failure were significantly higher in Group IV than in all other groups (P < 0.05). Histologic analysis demonstrated a qualitative increase in fusion mass in Group IV versus all other groups. CONCLUSIONS: Direct-current electrical stimulation increased fusion rates in a dose-dependent manner in a rabbit spinal fusion model. Coralline hydroxyapatite is an osteoconductive bone graft substitute, and thus requires an osteoinductive stimulus to ensure reliable fusion rates. Furthermore, coralline hydroxyapatite and direct current electrical stimulation can be used together to increase fusion rates in a rabbit spinal fusion model while avoiding the morbidity associated with harvesting iliac crest bone.

Asunto(s)

RESUMEN

CLINICAL RELEVANCE: Low back pain from lumbar spinal stenosis is a significant source of morbidity, especially among the elderly population. Accurate diagnosis is imperative for effective treatment to be initiated. This paper presents a quantitative method for the evaluation of spinal stenosis that, when used in conjunction with CT and MRI, may greatly aid the clinician in the diagnosis of this debilitating condition. OBJECTIVE: Precise clinical tools for the diagnosis of spinal stenosis are severely lacking. Low back pain and dysfunction derived from lumbar spinal stenosis is a significant source of morbidity, especially among the elderly. Despite its importance, there has been little progress made towards establishing valid, quantitative criteria for the diagnosis of spinal stenosis. We present a new quantitative tool for the diagnosis of lumbar stenosis, the Stenosis Ratio (SR). METHODS: CT scans and MRI scans of 43 patients presenting with clinico-radiographic evidence of lumbar stenosis were used. The patient group consisted of 13 males and 30 females between the ages 49 and 82 with average age of 67. CT and MRI/scans of 43 patients were digitized and computer analyzed. Measurements of SR, defined as the ratio of the cross-sectional dural area of the motion segment to that of the stable segment, were established for L3-L4, L4-L5 and L5-S1 stenotic levels and compared to SR values for a non-stenotic (internal control) level, L2-L3. RESULTS: The L4-L5 level had the lowest SR value of 0.71, followed by 0.74 at L3-L4, and 0.87 at L5-S1. Ninety-five percent confidence intervals of (0.66, 0.81), (0.62, 0.81), and (0.73, 1.00) were found for SR values at levels L3-L4, L4-L5 and L5-S1 respectively. The SR at L2-L3 had a mean value of 1.37 with a 95% confidence interval of (0.970, 1.78). At all levels, SRs were significantly lower for the spinal stenotic L3-S1 levels than for the L2-L3 control as confirmed by a student's t-test (p < 0.05). CONCLUSION: In a select population of patients with spinal stenosis confirmed by neuroradiological assessment, values of SRs were consistently and significantly lower than controls. We believe that measurements of SRs may provide reproducible quantitative measures for the diagnosis of spinal stenosis. SR values below the 95% confidence limit may be indicative of lumbar stenosis. Through the use of ratios, inherent differences in patient size are controlled for, thus allowing comparison of values between patients and treatment groups and effective clinical diagnosis of spinal stenosis.

Asunto(s)

RESUMEN

Indications for operative treatment in spinal metastatic disease depend on estimates of vertebral loadbearing capacity. There are no noninvasive diagnostic tools for estimating vertebral loadbearing capacity in the presence of a metastatic lesion. Thus, relationships between vertebral failure load and measurements from computed tomography data were investigated to determine if measurements that account for defect size and bone density can predict loadbearing capacity better than can defect size alone. Cylindrical defects were created in thoracic vertebrae of 20 anatomic specimen spinal segments, with 10 other segments serving as controls. Five vertebrae with actual metastatic defects also were tested. Vertebrae were scanned using quantitative computed tomography, and the defect size and the axial rigidity of the midvertebral cross section were calculated using an image analysis program. The spinal segments were tested to failure using a combination of axial compression and anterior flexion. Linear regressions between axial rigidity and absolute failure load showed a high positive correlation, but there was no correlation between defect size and failure load. Axial rigidity may prove useful as a noninvasive assessment of vertebral loadbearing capacity in patients with spinal metastatic disease.

Asunto(s)

RESUMEN

STUDY DESIGN: Prospective observational study. OBJECTIVES: To examine associations between radiographic parameters (scoliosis and olisthesis) and outcomes of surgery for degenerative spinal stenosis. SUMMARY OF BACKGROUND DATA: Preoperative degenerative scoliosis generally is thought to be associated with an unfavorable outcome of surgery for spinal stenosis. Data on the relationship between an increase in olisthesis after laminectomy for spinal stenosis and outcomes of surgery are sparse and conflicting. METHODS: Radiographs were obtained before surgery and at least 6 months after surgery and coded for preoperative scoliosis and change in olisthesis after surgery. The reviewers of radiographs were blind to outcome information. Patients completed questionnaires on demographic and clinical data as well as on back pain, lower extremity pain, walking capacity, and satisfaction with surgery. Associations between radiographic data and patient reported outcomes were examined with the Spearman rank correlation and confirmed with multiple linear regression models that adjusted for potential confounders. RESULTS: Ninety patients met eligibility criteria. Preoperative scoliosis was associated with less improvement in back pain at 6 months and at 24 months after surgery. An increase in olisthesis after surgery was associated with greater improvement in lower extremity pain at 6 months and at 24 months after surgery. An increase in olisthesis also was associated with greater improvement in walking capacity at 6 months and at 24 months after surgery. In multivariable analyses that adjusted for potential confounders, a change in olisthesis was not associated significantly with greater improvement in any of the outcomes. CONCLUSION: The data support the widely held view that preoperative scoliosis is associated with an unfavorable outcome after decompression for degenerative lumbar spinal stenosis. Increase in olisthesis was not associated with unfavorable results. In fact, there was a weak trend toward better outcomes with greater slip. These data indicate that minor increases in olisthesis after surgery for spinal stenosis generally are tolerated well.

Asunto(s)

RESUMEN

DESIGN: A prospective, multicenter observational study. OBJECTIVES: 1) Identify correlates of the decision to perform arthrodesis in patients undergoing laminectomy for lumbar spinal stenosis. 2) Compare symptoms, walking capacity, and satisfaction 6 and 24 months after laminectomy alone and laminectomy with noninstrumented and with instrumented arthrodesis. BACKGROUND DATA: Few prospective studies have compared outcomes of laminectomy alone or laminectomy with noninstrumented or with instrumented arthrodesis in patients with degenerative lumbar spinal stenosis. There is uncertainty regarding the optimal use of arthrodesis and instrumentation. METHODS: Two hundred seventy--two patients undergoing--surgery for degenerative lumbar stenosis by eight surgeons at four centers were included in the study cohort. Of these, 37 had noninstrumented and 41 had instrumented arthrodesis. Logistic regression identified factors associated with arthrodesis. The principal outcomes-health status, walking capacity, back and leg pain, and satisfaction with surgery-were assessed 6 and 24 months postoperatively with univariate and multivariate techniques. Outcomes also were assessed in a restricted cohort of patients with at least 5 mm spondylolisthesis and/or 15 degrees scoliosis. Hospital costs were obtained from a computerized hospital cost accounting system. RESULTS: The major predictor of the decision to perform arthrodesis was the individual surgeon (P = 0.0001). Noninstrumented arthrodesis was associated with superior relief of low back pain at 6 months (P = 0.004) and 24 months (P = 0.01). This difference persisted in multivariate analyses, with borderline statistical significance. There were no significant differences in the other outcomes across treatment groups. Mean hospital costs of laminectomy alone and noninstrumented and instrumented arthrodesis were $12,615, $18,495, and $25,914, respectively (P = 0.0001). CONCLUSION: Findings were limited by the small number of participating surgeons, modest sample size that produced P values of borderline significance, and nonrandomized design. With these caveats in mind, the authors conclude: (1) The individual surgeon was a more important correlate of the decision to perform arthrodesis than clinical variables such as spondylolisthesis. (2) Noninstrumented arthrodesis resulted in superior relief of back pain after 6 and 24 months. (3) Instrumented arthrodesis was the most costly option. These results highlight the need for randomized controlled trials and cost effectiveness analyses of lumbar arthrodesis and instrumentation in patients with degenerative lumbar spinal stenosis.

Asunto(s)

RESUMEN

STUDY DESIGN: The measurement properties and validity of a newly developed patient questionnaire for the assessment of patients with lumbar spinal stenosis was tested in an ongoing prospective multicenter observational study of patients undergoing decompressive surgery in three teaching hospitals. OBJECTIVE: The goal of the study was to develop a short, self-administered questionnaire on symptom severity, physical functional status, and patient satisfaction. SUMMARY OF BACKGROUND DATA: The measure is intended to complement existing generic measures of spinal-related disability and health status. The questionnaire includes three scales with seven questions on symptom severity, five on physical function, and six on satisfaction. METHODS: The internal consistency of the scales was assessed with Cronbach's coefficient alpha on cross-sectional data from 193 patients before surgery. The test-retest reliability was assessed on data from a random sample of 23 patients using Spearman's rank correlation coefficient. The responsiveness was assessed on 130 patients with 6-month follow-up data using the standardized response mean. RESULTS: The test-retest reliability of the scales ranged from 0.82 to 0.96, the internal consistency from 0.64 to 0.92, and the responsiveness from 0.96 to 1.07. The direction, statistical significance, and strength of hypothesized relationships with external criteria were as expected. CONCLUSIONS: This short self-administered spinal stenosis measure is reproducible, internally consistent, valid, and highly responsive. It can be used to complement generic instruments in outcome assessment of patients with lumbar spinal stenosis.

Asunto(s)

RESUMEN

STUDY DESIGN: Retrospective review and prospective follow-up of 88 patients who had decompressive laminectomy with or without fusion from 1983 to 1986. OBJECTIVE: To determine the 7- to 10-year outcome of surgery for degenerative lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: There is limited information on the impact of surgery for lumbar spinal stenosis on symptoms, walking ability, and satisfaction, as well as reoperation. METHODS: Patients completed standardized questionnaires in 1993 that included items about reoperations, back pain, leg pain, walking capacity, and satisfaction with surgery. Associations between preoperative demographic and clinical variables and outcomes 7 to 10 years after surgery were evaluated in univariate and multivariate analyses. RESULTS: Average preoperative age was 69 years and eight patients received fusion. Of 88 patients in the original cohort, 20 (23%) were deceased and 20 (23%) had undergone reoperation by 7- to 10-year follow-up. Fifty-five patients answered questionnaires. Average duration of follow-up was 8.1 years. Thirty-three percent of the respondents had severe back pain at follow-up, 53% were unable to walk two blocks, and 75% were satisfied with the results of surgery. The severity of current spine-related symptoms was a stronger correlate of physical functional status at the time of follow-up than age or nonspinal comorbid conditions. CONCLUSIONS: Seven to 10 years after decompressive surgery for spinal stenosis, 23% of patients had undergone reoperation and 33% of respondents had severe back pain. Despite a high prevalence of nonspinal problems in this elderly cohort, spinal symptoms were the most important correlate of reduced functional status.

Asunto(s)

RESUMEN

A multidisciplinary group of clinicians and administrators were convened to find innovative ways to contain costs and improve the quality of care on an inpatient orthopedic unit. This group was charged with examining all phases of care and recommending changes. The team proved to be a model of effective, successful collaboration and has enabled ambitious goals to be realized on this unit. The article outlines changes related to preoperative, intraoperative, and postoperative care and discusses the dynamics of effective interdisciplinary professional collaboration.

Asunto(s)

RESUMEN

OBJECTIVE: To assess the value of the history and physical examination findings in the diagnosis of symptomatic degenerative lumbar spinal stenosis (LSS). METHODS: The study was performed in 3 specialty clinics, and included patients with low back pain who were at least age 40. Findings from a standardized history and physical examination were compared with the diagnostic impression of expert attending clinicians. Imaging studies were available in 88% of those with LSS, and the findings further supported the diagnosis of LSS in each case. The sensitivity, specificity, and likelihood ratio associated with each history and physical examination finding were calculated in bivariate analyses, and independent correlates of LSS were identified with multivariate analyses. RESULTS: Ninety-three patients were evaluated. History findings most strongly associated with the diagnosis of LSS (likelihood ratio > or = 2) were greater age, severe lower-extremity pain, and absence of pain when seated. Physical examination findings most strongly associated with the diagnosis were wide-based gait, abnormal Romberg test result, thigh pain following 30 seconds of lumbar extension, and neuromuscular deficits. Independent correlates of LSS included advanced age (P = 0.0001), absence of pain when seated (P = 0.006), wide-based gait (P = 0.013), and thigh pain following 30 seconds of lumbar extension (P = 0.002). CONCLUSION: Specific history and physical examination findings are useful in the diagnosis of LSS and should be ascertained routinely in older patients with low back pain.

Asunto(s)

RESUMEN

STUDY DESIGN: Prospective multicenter observational study of the outcome of surgery for degenerative lumbar spinal stenosis. OBJECTIVES: To identify correlates of patient satisfaction with the results of surgery. SUMMARY OF BACKGROUND DATA: Little published information exists on correlates of patient satisfaction after surgery for spinal stenosis. METHODS: Preoperative and 6-month follow-up data for 194 patients were analyzed. Associations between preoperative variables and satisfaction with the results of surgery were examined in univariate and multivariate models. RESULTS: In multiple linear regression models that adjusted for the effects of age, gender, individual surgeon, number of interspaces decompressed, whether a fusion was performed, depression score, and overall level of pain, the predominance of back (as opposed to leg) pain, greater comorbidity, and worse preoperative functional status were associated with lower patient satisfaction. The regression model explained just 15% of the variance in patient satisfaction. CONCLUSIONS: Patients bothered predominantly by back pain preoperatively and those with greater medical comorbidity and functional disability are significantly less satisfied with the results of surgery for degenerative lumbar spinal stenosis.

Asunto(s)

RESUMEN

OBJECTIVE: To evaluate the relationship between neuromuscular impairment and physical functional status in patients with lumbar spinal stenosis. METHODS: Cross sectional analysis of 217 consecutive patients with lumbar spinal stenosis referred to 3 teaching hospitals. Physical functional status was measured with the physical dimension of the Sickness Impact Profile (P-SIP). Physical and radiological findings were abstracted from clinical records. The neuromuscular findings included pin sensation, strength, deep tendon reflexes and vibration. They were aggregated in a neuromuscular impairment index (NMI). Univariate relationships of the P-SIP and the NMI were analyzed with nonparametric methods. The determinants of physical functional status were evaluated using multiple linear regression models. RESULTS: In 148 patients with complete clinical data, objective weakness of the lower extremity as measured at rest was not related to physical functional status in univariate analyses. Decreased vibration was common and was associated with balance disturbance and reduced physical functional status, reflecting the importance of proprioception loss. In the multivariate regression analysis, neuromuscular deficit explained only 2.5% of the variance in physical functional status. The primary determinants of physical functional status were pain, depression, comorbid conditions and work status. CONCLUSION: While neuromuscular impairment is an indispensable feature of the diagnostic evaluation, its value in assessing outcome is limited. The decision whether to intervene surgically in patients without cauda equina syndrome or rapidly progressive neurological deficits should therefore be driven by pain and physical disability rather than the degree of neuromuscular impairment.

Asunto(s)

RESUMEN

Lumbar spinal stenosis is a clinical-anatomic syndrome. Radiographic evidence of cauda equina compression is necessary but not sufficient to establish the diagnosis. Patients must have a clinical syndrome consisting of back and lower extremity discomfort exacerbated by lumbar extension or relieved by flexion, or evidence of lower extremity neurologic deficits. Symptomatic lumbar spinal stenosis may arise from a variety of specific etiologies and frequently coexists with other pain syndromes.

Asunto(s)

RESUMEN

OBJECTIVE: To report a case of Stevens-Johnson syndrome caused by vancomycin. CASE SUMMARY: Stevens-Johnson syndrome is an acute mucocutaneous process characterized by epidermal and mucosal desquamation. Its pathogenesis is poorly understood. Mortality rates have ranged from 30 to 100 percent. We describe a case of Stevens-Johnson syndrome related to the use of vancomycin in a 71-year-old woman with rheumatoid arthritis receiving treatment for an infected cervical fusion site. Classic "target" lesions distributed throughout the trunk and extremities along with erosive lesions involving the oral and vaginal mucosae were observed in this patient. DISCUSSION: A number of agents have been implicated in the etiology of Stevens-Johnson syndrome. Serious cutaneous reactions to vancomycin, however, have been uncommon. Cessation of vancomycin treatment in our patient led to eventual resolution of her symptoms. CONCLUSIONS: Vancomycin is a potential causative agent of Stevens-Johnson syndrome.

Asunto(s)

Asunto(s)

RESUMEN

The outcome of laminectomy for the relief of symptoms resulting from degenerative lumbar stenosis is not well established. Eighty-eight consecutive patients who had had a laminectomy for degenerative lumbar stenosis between 1983 and 1986 were studied. Eight of the patients had had a concomitant arthrodesis. The follow-up evaluation included a review of charts and standardized questionnaires that were completed by the patients. One year postoperatively, five patients (6 per cent) had had a second operation and five still had severe pain. By the time of the latest follow-up, in 1989, fifteen (17 per cent) of the original eighty-eight patients had had a repeat operation because of instability or stenosis; twenty-one (30 per cent) of the seventy patients who were evaluated by questionnaire in 1989 had severe pain. The factors found to be associated with a poor long-term outcome, defined as severe pain or the need for a repeat operation, or both, included co-existing illnesses (such as osteoarthrosis, cardiac disease, rheumatoid arthritis, or chronic pulmonary disease) (p = 0.004), the duration of follow-up (p = 0.01), and an initial laminectomy involving a single interspace (p = 0.04). We concluded that the long-term outcome of decompressive laminectomy is less favorable than has been previously reported, and that co-morbidity and a single-interspace laminectomy are risk factors for a poor outcome.

Asunto(s)

RESUMEN

A case of spinal cord compression arising from ossification of the ligamentum flavum in an African-American is presented. Myelography and computed tomography were used to delineate the anatomy.

Asunto(s)

RESUMEN

Rheumatoid arthritis causes synovitis in the cervical spine and injures skeletal structures at any level. Subluxations occur with pain and spinal cord dysfunction. Subluxations are common; neurological problems are less so, but death from subluxations is not common. However, once myelopathy is established, the natural history is poor. Advances in radiologic imaging through computed tomography and magnetic resonance imaging greatly assist anatomic assessment. Neurologic deterioration and pain are indications for surgery. Preoperative skeletal traction is often required to align the spine, and fusion techniques are used for stabilization.

Asunto(s)

RESUMEN

Degenerative spinal stenosis is the most common type of stenosis encountered, often presenting with neurogenic claudication. History and physical examination indicate its presence and radiologic imaging is used to demonstrate the spatial reduction in the lumbar canals. Nonoperative therapy can be effective while surgical decompression offers the most reliable and definitive therapeutic intervention.

Asunto(s)

RESUMEN

It is hypothesized on the basis of experimental intervertebral disc degeneration that herniated disc is actually newly synthesized proliferative metaplastic fibrocartilage and not herniation of pre-existing disc tissue, particularly that of the nucleus pulposus. Human material in selected surgical tissues was examined to test this concept. Histology revealed evidence for proliferative fronts of fibroblastic cells in herniated discs with hypocellular interiors. Hydroxypyridinium cross-link assay was used to determine the maturity of the collagen. Results indicated, with statistical significance, that herniated disc is a younger tissue than in situ annulus fibrosis, and that herniated disc is not from the nucleus pulposus, thus supporting the hypothesis.

Asunto(s)