Surgical treatment of lumbar stenosis: long-term results

Biomechanical comparison of facet-sparing laminectomy and Christmas tree laminectomy

OBJECT

The authors compared differences in biomechanical stability between two decompressive laminectomy techniques for treating lumbar stenosis. A Christmas tree laminectomy (CTL), in which bilateral facetectomies and foraminotomies are performed, was compared with facet-sparing laminectomy (FSL), in which the facets are undercut but not resected. Spinal instability was assessed immediately postoperatively and again after discectomy to model long-term degeneration.

METHODS

Sixteen motion segments obtained from five human cadaveric lumbar specimens were studied in vitro by conducting nondestructive flexibility tests. Specimens were tested intact, after FSL or CTL, and again after discectomy. Nonconstraining torques (< or = 5 Nm) were applied to induce flexion, extension, axial rotation, and lateral bending; strings and pulleys were used while vertebral angles were measured. Anteroposterior translation in response to shear loading (< or = 100 N) was also measured. Angular motion, shear motion, and sagittal-plane axes of rotation were compared to evaluate stability. Compared with the intact condition, CTL-treated specimens had significantly larger increases in angular motion during flexion, lateral bending, and axial rotation than their FSL-treated counterparts (p < 0.05, nonpaired Student t-tests). Subsequent discectomy caused greater increases in motion in the CTL group. Axes of rotation shifted less from their normal positions after FSL than after CTL.

CONCLUSIONS

This study provides objective evidence that the treatment of lumbar stenosis with FSL induces less biomechanical instability and alters kinematics less than FSL. These findings support the use of the FSL in treating lumbar stenosis.

Calcium pyrophosphate dihydrate crystal deposition disease as a cause of lumbar canal stenosis

STUDY DESIGN

This study measured the incidence of calcium pyrophosphate dihydrate crystal deposition in specimens of ligamenta flava in consecutive patients undergoing decompressive laminectomy between 1984 and 1991. The results were compared to determine the difference between calcium pyrophosphate dihydrate-negative patients with lumbar canal spinal stenosis.

OBJECTIVES

The results were compared with cadaver specimens and literature values to determine if calcium pyrophosphate dihydrate crystal deposition disease contributes to the thickening of the ligamentum flavum and thereby contributes to spinal stenosis.

SUMMARY OF BACKGROUND DATA

Calcium pyrophosphate dihydrate crystal deposition disease has been described in the axial skeleton. Hypertrophy of the ligamentum flavum has been suggested to contribute to stenosis. The association of calcium pyrophosphate dihydrate disease and hypertrophied ligamenta flava has not been fully defined nor linked to neurologic symptoms and signs.

METHODS

The incidence of calcium pyrophosphate dihydrate crystal deposition in specimens of ligamenta flava obtained from four groups was measured: specimens obtained during surgery from 102 consecutive patients undergoing decompression laminectomy between 1984 and 1991, 47 additional pathologic specimens of ligamentum flavum tested between 1984 and 1991, 222 calcium pyrophosphate dihydrate-positive Pathology Department specimens collected between 1980 and 1991, and, as control specimens from 20 cadavers. The associated patient histories were reviewed for the first two groups; no histories were available for the cadaver group.

RESULTS

The incidence of calcium pyrophosphate dihydrate crystal deposition was 24.5% in the ligamentum flavum among the surgical patients, 31% among the Pathology Department specimens, 33.8% among the calcium pyrophosphate dihydrate-positive Pathology Department specimens, and 5% among the cadavers. No associated medical conditions with calcium pyrophosphate dihydrate crystal deposition were found among the medical histories. Patients with the symptoms of spinal stenosis who were also calcium pyrophosphate dihydrate-negative patients with symptoms of less than 6 months' and less than 24 months' duration (P < 0.001). Except for time to presentation, calcium pyrophosphate dihydrate-negative patients had similar signs and symptoms of lumbar canal spinal stenosis. Having previous spine surgery did not produce a statistically significant risk of having calcium pyrophosphate dihydrate crystal deposition. No specific laboratory tests were found to be of predictive value.

CONCLUSIONS

These findings suggest that calcium pyrophosphate dihydrate crystal deposition may indeed be associated with the thickening of the ligamentum flavum, if so, patients may benefit from medical treatment before undergoing surgical treatment of lumbar canal spinal stenosis.

Factors influencing the outcome of operative treatment for lumbar spinal stenosis

96 patients with lumbar spinal stenosis were operated on after two to sixteen years of disabling symptoms. There were 50 women and 46 men with a mean age of 59 years. 33 of the patients had been previously operated on for spinal complaints. A laminectomy was performed in 61 patients; at one level in 31 patients, at two levels in 23 patients, and at three levels in seven patients. A hemilaminectomy was performed in 35 patients: at one level in 28 patients, at two levels in five patients, and at three levels in two patients. There were neither internal fixation devices used, nor spondylodesis performed in these operations. Special attention was focused on the effect of age, sex, body mass index and smoking, as well as previous surgery and extent of surgical intervention on the outcome of operative treatment. The follow-up time was 3-11 years (5.5 mean). Laminectomy at one level resulted in significantly most acceptable results of operative treatment methods. Younger patients and women were more prone to inferior results of operative treatment. Also the extent of surgical intervention, overweight and smoking seemed to have a tendency to worsen the result of operative treatment.

Surgical treatment of lumbar spinal stenosis: patients' postoperative disability and working capacity

A total of 439 patients operated on for lumbar spinal stenosis during the period 1974-1987 was re-examinated and evaluated for working and functional capacity approximately 4 years after the decompressive surgery. The assessment of subjective disability was based on the Oswestry low-back pain questionnaire. The proportion of excellent-to-good outcomes was 62% (women 57%, men 65%). The ability to work before or after the operation and a history of no prior back surgery were variables predictive of a good outcome. Before the operation 86 patients were working, 223 patients were on sick leave, and 130 patients were retired. After the operation 52 of the employed patients and 70 of the unemployed patients returned to work. None of the retired patients returned to work. In logistic regression analysis the ability to work preoperatively, age under 50 years at the time of operation and the absence of prior back surgery predicted a postoperative ability to work. Our results suggest that more attention should be focussed on the diagnosis of spinal stenosis and on the timing of the operative intervention.

Lumbar spine surgery and mortality among Medicare beneficiaries, 1986

OBJECTIVES

The purpose of this study was to compare lumbar spine surgical procedures by age, gender, and number of comorbidities with respect to mortality in patients 65 years of age and older in the United States.

METHODS

A 100% sample of the 1986 Medicare inpatient Health Care Financing Administration claims files databases involving lumbar spine surgical procedures was analyzed.

RESULTS

Lumbar spine surgery in 34,418 patients (median age = 71 years) was associated with a significant increase in in-hospital and 1-year cumulative mortality only beyond 80 years of age. When adjusted for age, in-hospital and 1-year cumulative mortality with both decompression and excision procedures were significantly higher in men than in women. When adjusted for both age and gender, mortality increased significantly as the number of comorbidities increased.

CONCLUSIONS

With lumbar spine surgery in elderly patients, mortality did not significantly increase until 80 years of age and was consistently associated with decompression and excision, with male gender, and with an increase in number of comorbidities.

Decompressive lumbar laminectomy for spinal stenosis

A total of 258 consecutive decompressive lumbar laminectomies performed on 244 individuals presenting with spinal stenosis were analyzed retrospectively. Spinal fusion was avoided in all but two patients. Outcome in terms of pain relief and return to normal activity was evaluated in two stages, one derived from patient charts and having a relatively short-term follow-up time (mean 8.4 months) and a second derived from patient responses to a questionnaire (which also scored for satisfaction with the results of surgery), which had a longer follow-up time (mean 4.7 years). More than 20 clinical and operative parameters were analyzed. Overall, a high degree of success (93% pain relief, 95% return to normal activity) was achieved in the short term, which was supported by the longer-term follow-up data (64% pain relief, 56% activity return, 75% satisfaction). The following factors were not significantly correlated with outcome: patient age; sex; worker's compensation or no-fault insurance status; employed versus not employed; a history of back surgery prior to the laminectomy studied; existence of degenerative spondylolisthesis or scoliosis; complete versus incomplete myelographic block; or the level of the lumbar spine undergoing surgery. The major conclusions arising from these data are: 1) for all age groups through at least the eighth decade of life, decompressive lumbar laminectomy is a relatively safe operation having a high medium-to-long-term success rate; 2) lumbar instability following laminectomy is rare, even in individuals presenting prior to surgery with degenerative instability conditions; and 3) lumbar fusion in addition to the decompressive laminectomy procedure is rarely required for degenerative spinal stenosis.

Surgical results and complications in elderly patients with benign lesions of the spinal canal

OBJECTIVE

To describe the long-term outcome and complications of spinal surgery in a population of elderly patients.

DESIGN

Retrospective chart review and clinical follow-up.

SETTING

A 700-bed tertiary care midwestern hospital.

PATIENTS

Patients 70 years of age or older who underwent elective surgical procedures for the treatment of benign lesions of the spinal canal.

MAIN OUTCOME MEASURES

Data obtained from chart review included age, sex, nature and duration of neurological symptoms, activities of daily living (ADL), associated illnesses, length of hospitalization, type of surgery, and complications attributable to surgery. Outcome measurements included changes in neurological symptoms and ADL and a standardized scale obtained from consecutive outpatient visits, telephone interviews, or written responses.

RESULTS

Seventy-eight patients with lumbar canal stenosis or soft disc herniations underwent laminectomies, foraminotomies or discectomies. Eleven patients underwent cervical laminectomies for multilevel spondylitic myelopathy. Limb and spine pain were the most common neurological symptoms in patients with lumbar lesions; diminished ADLs were present in eight patients with cervical myelopathies. Six patients died of unrelated causes, and 78 were followed for an average of 27.1 months. Twenty-three (85.2%) of 27 patients with lumbar disc herniations reported improvements or resolution of limb pain while 35 (81.4%) of 43 patients with lumbar canal stenosis reported fair or good results. Five of eight patients with multilevel cervical spondylosis reported improvements of myelopathic symptoms. Twenty-six (28.6%) complications were attributable to 91 surgical procedures including five severe complications and one fatality. Patients with three or more associated illnesses demonstrated a significantly higher incidence of postoperative complications.

CONCLUSIONS

Elderly patients with benign lesions of the spinal canal may achieve significant reduction in limb pain and increases in ADL following appropriate surgery, with a tolerable rate of severe complications. The preoperative physical condition of the elderly patient served as an indicator for operative morbidity.