Outcome after laminectomy for lumbar spinal stenosis. Part I: Clinical correlations

How does neuropathophysiology affect the signs and symptoms of spinal disease?

A complex relationship exists between back pain and the presence of spinal disease. Particularly in chronic situations, back pain and its behavioural and emotional consequences are as likely to reflect the influence of psychosocial factors as any underlying spinal pathology. Nevertheless, physical factors are clearly important and it is significant that whereas in normal discs only the outer third of the annulus fibrosus is innervated, a much more extensive innervation develops in the presence of degeneration. Inflammation, as evidenced by leukocyte infiltration and expression of inflammatory mediators, is associated with disc degeneration and serves to alter the neural responses resulting in local and referred pain. It is probable that similar inflammatory processes, as well as direct root compression, contribute to radicular symptoms following disc herniation. An appreciation of these mechanisms encourages the search for novel treatments and permits a more rational and effective use of existing strategies for relieving pain.

Decompression, fusion, and instrumentation surgery for complex lumbar spinal stenosis

Between 1990 and 1993, 54 consecutive patients were treated with decompression, fusion and instrumentation surgery for complex lumbar spinal stenosis. The mean age of the patients was 60 years. The average followup was 39 months. Clinically, there was one deep wound infection, and three mechanical failures. There were two staged operations. There were three revision surgeries performed for mechanical reasons. Of the 47 patients who completed the questionnaire, 96% of patients were very satisfied or somewhat satisfied with the operation, 98% were satisfied with relief of pain, 94% were satisfied with their ability to walk, 89% were satisfied with their strength, and 94% were satisfied with balance. Survivorship analysis (failure endpoint was revision surgery) revealed that at the end of 4 years, the patient had a 92% chance of not undergoing revision surgery for any reason (mechanical and infectious), and a 94% chance of not undergoing revision surgery for mechanical reasons. Lumbar decompression, fusion, and instrumentation surgery seems to be efficacious in patients with complex lumbar spinal stenosis (associated previous lumbar spine operations with evidence of radiographic instability, radiographic evidence of junctional stenosis after surgery, radiographic evidence of instability, degenerative spondylolisthesis greater than Grade I with instability, if present, and degenerative scoliosis with a curve greater than 20 degrees).

Current techniques of decompression of the lumbar spine

Lumbar spinal decompression is a commonly performed procedure. Although the conventional open techniques of decompression remain the gold standard of treatment, problems with paraspinal musculature denervation and resultant lumbar instability have focused attention on less invasive techniques. A multitude of spinal instrumentation systems have been developed to stabilize the spine and improve arthrodesis rates. A stronger emphasis on restoration of anterior column height and stability has increased the use of anterior interbody fusion devices. Developing technology is allowing for better visualization and possibly improved outcomes with minimally-invasive techniques. The results of all lumbar decompressive and stabilization procedures however, remain closely related to careful patient selection.

Decompressive surgery for typical lumbar spinal stenosis

Between 1991 and 1992, 103 consecutive patients (average age, 65 years) underwent decompressive surgery for treatment of typical lumbar spinal stenosis. Clinical results at 1-year followup revealed that four patients had revision surgery. At 2- to 5-years followup, there were no additional revision surgeries. Two patients underwent revision surgery for a deep infection, and two underwent revision surgery for a superficial infection. Outcome results showed that 77 patients completed the questionnaire, 15 were lost to followup and 11 died. Postoperative results showed that 64 of 77 patients had no or mild pain, 72 of 77 patients stated that they were satisfied or somewhat satisfied with their overall results of surgery, and 73 of 77 were satisfied with pain relief. Younger patients had greater improvement in function and a greater reduction in severity scores. However, satisfaction was similar in both groups. Survivorship results (failure was revision surgery) showed at the end of 4 years, a patient had a 95% chance of not having revision surgery. Statistically, there was no association between outcome and cofactors such as scoliosis, spondylolisthesis, number of levels decompressed, discectomy, or smoking. Satisfaction rates for older patients were similar to patients younger than 65 years although physical function scores and severity scores were less.

Lumbar spinal stenosis: conservative or surgical management?: A prospective 10-year study

STUDY DESIGN

A cohort of 100 patients with symptomatic lumbar spinal stenosis, characterized in a previous article, were given surgical or conservative treatment and followed for 10 years.

OBJECTIVES

To identify the short- and long-term results after surgical and conservative treatment, and to determine whether clinical or radiologic predictors for the treatment result can be defined.

SUMMARY OF BACKGROUND DATA

Surgical decompression has been considered the rational treatment. However, clinical experience indicates that many patients do well with conservative treatment.

METHODS

In this study, 19 patients with severe symptoms were selected for surgical treatment and 50 patients with moderate symptoms for conservative treatment, whereas 31 patients were randomized between the conservative (n = 18) and surgical (n = 13) treatment groups. Pain was decisive for the choice of treatment group. All patients were observed for 10 years by clinical evaluation and questionnaires. The results, evaluated by patient and physician, were rated as excellent, fair, unchanged, or worse.

RESULTS

After a period of 3 months, relief of pain had occurred in most patients. Some had relief earlier, whereas for others it took 1 year. After a period of 4 years, excellent or fair results were found in half of the patients selected for conservative treatment, and in four fifths of the patients selected for surgery. Patients with an unsatisfactory result from conservative treatment were offered delayed surgery after 3 to 27 months (median, 3.5 months). The treatment result of delayed surgery was essentially similar to that of the initial group. The treatment result for the patients randomized for surgical treatment was considerably better than for the patients randomized for conservative treatment. Clinically significant deterioration of symptoms during the final 6 years of the follow-up period was not observed. Patients with multilevel afflictions, surgically treated or not, did not have a poorer outcome than those with single-level afflictions. Clinical or radiologic predictors for the final outcome were not found. There were no dropouts, except for 14 deaths.

CONCLUSIONS

The outcome was most favorable for surgical treatment. However, an initial conservative approach seems advisable for many patients because those with an unsatisfactory result can be treated surgically later with a good outcome.

Surgical and nonsurgical management of lumbar spinal stenosis: four-year outcomes from the maine lumbar spine study

STUDY DESIGN

A prospective cohort study of patients with lumbar spinal stenosis recruited from the practices of orthopedic surgeons and neurosurgeons throughout Maine.

OBJECTIVE

To assess 4-year outcomes for patients with lumbar spinal stenosis treated surgically or nonsurgically.

SUMMARY OF BACKGROUND DATA

Surgery for lumbar spinal stenosis has increased dramatically despite the lack of randomized trials comparing surgical with nonsurgical treatments. Long-term evaluation of surgical series has documented deterioration in initial symptomatic improvement, but few studies have compared long-term outcomes of surgical and nonsurgical treatment.

METHODS

Eligible, consenting patients had baseline interviews with mailed follow-up questionnaires at 3, 6, and 12 months, then annually thereafter. Clinical data were obtained at baseline from a physician questionnaire. Outcomes included patient-reported symptoms of leg and back pain, functional status, and satisfaction.

RESULTS

Of 148 patients with lumbar spinal stenosis initially enrolled, 4-year outcomes were available on 119 patients (80.4%): 67 of 81 (83%) treated surgically and 52 of 67 (78%) treated nonsurgically. The surgically treated patients had more severe symptoms and worse functional status at baseline and better outcomes at 4-year evaluation than the nonsurgically treated patients. After 4 years, 70% of the surgically treated and 52% of the nonsurgically treated patients reported that their predominant symptom, either leg or back pain, was better (P = 0.05). Satisfaction of patients with their current state at 4 years was reported by 63% of the surgically treated and 42% of the nonsurgically treated patients (P = 0.04). Surgical treatment remained a significant determinant of 4-year satisfaction, even after adjustment for other independent predictors (P = 0.001). For the nonsurgically treated patients, there was no significant change in outcomes over 4 years, whereas the initial improvement seen in the surgically treated patients modestly decreased over the subsequent 4 years.

CONCLUSIONS

For the patients with severe lumbar spinal stenosis, surgical treatment was associated with greater improvement in patient-reported outcomes than nonsurgical treatment at 4-year evaluation, even after adjustment for differences in baseline characteristics among treatment groups. The relative benefit of surgery declined over time but remained superior to nonsurgical treatment. Outcomes for the nonsurgically treated patients improved modestly and remained stable over 4 years. Determining whether outcomes continue to converge will require longer-term evaluation.

Predictors of surgical outcome in degenerative lumbar spinal stenosis

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.

Long-term follow-up review of patients who underwent laminectomy for lumbar stenosis: a prospective study

OBJECT

Decompressive laminectomy for stenosis is the most common operation performed in the lumbar spine in older patients. This prospective study was designed to evaluate long-term results in patients with symptomatic lumbar stenosis.

METHODS

Between January 1984 and January 1995, 170 patients underwent surgery for lumbar stenosis (86 patients), lumbar stenosis and herniated disc (61 patients), or lateral recess stenosis (23 patients). The male/female ratio for each group was 43:43, 39:22, and 14:9, respectively. The average age for all groups was 61.4 years. For patients with lumbar stenosis, the success rate was 88.1 % at 6 weeks and 86.7% at 6 months. For patients with lumbar stenosis and herniated disc, the success rate was 80% at 6 weeks and 77.6% at 6 months, with no statistically significant difference between the two groups. For patients with lateral recess stenosis, the success rate was 58.7% at 6 weeks and 63.6% at 6 months; however, the sample was not large enough to be statistically significant. One year after surgery a questionnaire was sent to all patients; 163 (95.9%) responded. The success rate in patients with stenosis had declined to 69.6%, which was significant (p = 0.012); the rate for patients with stenosis and herniated disc was 77.2%; and that for lateral recess stenosis was 65.2%. Another follow-up questionnaire was sent to patients 1 to 11 years after surgery (average 5.1 years); 146 patients (85.9%) responded, 10 (5.9%) were deceased, and 14 (8.2%) were lost to follow-up review. At 1 to 11 years the success rate was 70.8% for patients with stenosis, 66.6% for those with stenosis and herniated disc, and 63.6% for those with lateral recess stenosis. Eleven patients who underwent reoperation were included in the group of patients whose surgeries proved unsuccessful, regardless of their ultimate outcome. There was no statistically significant difference in outcome between 1 year and 1 to 11 years with respect to stenosis, stenosis with herniated disc, and lateral recess stenosis.

CONCLUSIONS

In conclusion, long-term improvement after laminectomy was maintained in two-thirds of these patients.

Lumbar spinal stenosis: a review of current concepts in evaluation, management, and outcome measurements

The purpose of this review is to present current information from the literature regarding the pathoanatomy, clinical presentation, differential diagnosis, treatment, and outcome assessment methods for patients with lumbar spinal stenosis. Lumbar spinal stenosis is a frequently encountered condition, particularly in the elderly. Treatment requires an accurate diagnosis, but differential diagnosis of lumbar stenosis can be difficult. The literature to date has focused primarily on surgical treatment. The long-term efficacy of surgery has been questioned, and surgical procedures are associated with increased costs and risks of morbidity in an elderly population. A trial of conservative care is recommended in most cases, but there are presently no randomized controlled studies in the literature comparing surgical versus conservative management, or evaluating the effectiveness of any specific conservative treatment approach. The existing literature has further been criticized for having poorly defined outcome measures. The assessment of treatment outcomes should be multifactorial, including measures of pathoanatomy and impairments, as well as patient-centered measures such as level of disability, patient expectations, and satisfaction. The present level of understanding of lumbar spinal stenosis is deficient in many areas, including differential diagnosis, treatment, and outcome assessment. Future research should address these deficits to improve the management of patients with this condition.

Computer-assisted measurement of lumbar spine radiographs

RATIONALE AND OBJECTIVES

The authors evaluated a method for obtaining reproducible, reliable measurements from standard lumbar spine radiographs for determining the degree of spondylolisthesis, vertebral body height, intervertebral disk space height, disk space angle, and degree of vertebral body wedging.

MATERIALS AND METHODS

Four to six easily defined points were identified on each vertebral body on anteroposterior and lateral plain radiographs of the lumbosacral spine of patients. From these points, the degree of spondylolisthesis, the vertebral body height, the intervertebral disk space height, the disk space angle, and the degree of vertebral body wedging were easily calculated by using well-known geometric relationships. This method requires the use of a personal computer and a standard spreadsheet program but does not require the use of any other specialized radiographic equipment, computer hardware, or custom software.

RESULTS

Calculations of intra- and interobserver variability for the measurement of spondylolisthesis, disk space height, disk space angle, and vertebral body height measurement showed that the technique is extremely reproducible.

CONCLUSION

This technique may prove useful in the prospective evaluation of potential candidates for lumbar spinal stenosis surgery.

A population-based study of reoperations after back surgery

STUDY DESIGN

Longitudinal follow-up study of back surgery reoperations using an administrative database.

OBJECTIVES

To identify population-based rates and factors that determine the need for reoperation after back surgery.

SUMMARY OF BACKGROUND DATA

Reoperation after lumbar surgery has poorer results than the initial surgery, yet the population-based incidence and determinants of reoperation are not known. Reported rates of reoperation are derived from retrospective case series and range from 4% to 15%. There are conflicting data on the rate of reoperation after different types of initial surgery.

METHODS

All patients who had back surgery in the Province of Ontario (population 10,000,000) between April 1990 and March 1991 were identified using hospital discharge abstracts and an ICD-9 code algorithm. Patients who had undergone prior surgery were excluded. Patients were observed from the index operation to subsequent readmission and reoperation with a maximal time to follow-up examination of 4 years. Basic demographic information and information regarding diagnoses, surgery performed, complications, comorbid factors, reoperation diagnosis, and surgery type were obtained. Patients were divided into surgical treatment groups, and their subsequent reoperations were identified. Multivariate analysis using proportional hazards modeling was conducted.

RESULTS

The index surgery group consisted of 4,722 patients, of whom 449 (9.5%) underwent reoperations in the follow-up period. Complications from surgery were significantly higher in the fusion and fusion with decompression groups. The reoperation rate was not significantly different among individual surgery groups. Diagnosis, operation performed, complications after the index surgery, comorbid conditions, and sex did not predict the need for spine reoperation. Younger age was predictive of the likelihood of reoperation (P = 0.04)

CONCLUSION

The incidence of reoperation after back surgery is independent of diagnosis and type of surgery performed. Despite different anatomic reasons for surgical intervention, the success of different types of surgery are not influenced by the factors identified in this study. More extensive surgery does not prevent nor predispose a patient to the need for further surgery.

Quantitative outcome and radiographic comparisons between laminectomy and laminotomy in the treatment of acquired lumbar stenosis

OBJECTIVE

The objective of this study was to conduct a comparative quantitative analysis of outcomes, radiographic findings, and magnetic resonance imaging results after laminectomy or laminotomy was performed for patients with lumbar stenosis. Such as analysis had not previously been conducted.

METHODS

Twenty-six patients with no exclusion criteria who were treated surgically for acquired stenosis at the Division of Neurological Surgery at The Ohio State University from 1990 to 1993 were studied retrospectively. At follow-up examinations, each patient completed a detailed questionnaire that included visual analog scales, functional assessments, and the medical outcome study short form health survey, SF-36. Each patient underwent plain static and dynamic radiography that detailed vertebral body sagittal listhesis and rotation and magnetic resonance imaging that evaluated dural sac compression.

RESULTS

The mean follow-up duration was 36.7 months. Good outcome was defined by the presence of three criteria: no greater than mild leg pain (Grades 0-4), the ability to walk more than one block without developing lower extremity pain, and the ability to walk without assistance devices. Fifty-eight percent of the patients who had undergone laminectomies and 50% of the patients who had undergone laminotomies had good outcomes. All were judged to have had adequate decompression. The average maximum postoperative listhesis was 17.3 +/- 9.9% in the laminectomy group and 17.6 +/- 12.5% in the laminotomy group. In contrast to some previous studies, pre- or postoperative listhesis was not statistically related to outcome in either group. Patients in each poor outcome category seemed to have worse comorbid medical conditions than did patients in the good outcome category. The SF-36 measurements of poor functioning because of health factors and bodily pain correlated somewhat with poor outcomes in the patients who had undergone laminectomies. In patients who had undergone laminotomies, the only statistically significant finding among the outcome groups was the effect of poor emotional health on activity for the patients with poor outcomes.

CONCLUSION

This study indicates that laminotomy can adequately decompress lumbar canal stenosis, that laminectomy and laminotomy have the same degree of postoperative listhesis, and that the quantitative outcome of any treatment for lumbar stenosis is dependent not only on surgical factors but also on comorbid physical and psychological factors.

Clinical outcomes and radiological instability following decompressive lumbar laminectomy for degenerative spinal stenosis: a comparison of patients undergoing concomitant arthrodesis versus decompression alone

One hundred twenty-four patients with degenerative lumbar stenosis underwent decompression with fusion (32 patients) and without fusion (92 patients) during a 30-month period between 1986 and 1988. Patient-reported satisfaction at a mean follow-up period of 5.8 years (range 4.6-6.8 years) revealed a 79% good or fair outcome and a 21% poor outcome (26 patients). Seven patients (6%) developed lumbar instability, three patients (2%) developed new stenosis at an adjacent unoperated level, and three patients (2%) developed a new disc herniation between 2 and 5 years after surgery. Progressive postoperative spondylolisthesis occurred in 31% of patients with normal preoperative alignment (mean 7.8 mm, range 2-20 mm) and in 73% of patients with preoperative subluxation (mean 5.1 mm, range 2-13 mm) in whom fusion was not attained. Radiological progression did not correlate well with patient-reported outcome. The major conclusions from this study are the following: 1) the majority of patients respond well to this surgery, but complication (22%) and late deterioration (10%) rates are not insignificant; 2) radiological instability is common after decompression for degenerative lumbar spinal stenosis, but this correlates poorly with clinical outcome; 3) there are no definitive clinical or radiological factors that preoperatively predict patients at risk for a poor outcome; 4) post-operative radiological instability is more likely to occur when the following criteria are present: preoperative spondy-degenerated L-4 or a markedly degenerated L-3 disc; and when a radical and extensive decompression greater than one level is planned; and 5) the group at greatest risk for a poor outcome consists of those patients with normal preoperative alignment who do not suffer slippage following surgery.

Outcome after laminectomy for lumbar spinal stenosis. Part II: Radiographic changes and clinical correlations

The pre- and postoperative lumbar spine radiographs of 119 patients who underwent decompressive lumbar laminectomy were studied to evaluate radiographic changes and to correlate them with clinical outcome. An accurate and reproducible method was used for measuring pre- and postoperative radiographs that were separated by an average interval of 4.6 years. Levels of the spine that underwent laminectomy showed greater change in spondylolisthesis, disc space angle, and disc space height than unoperated levels. Outcome correlated with radiographic changes at operated and unoperated levels. This study demonstrates that radiographic changes are greater at operated than at unoperated levels and that some postoperative symptoms do correlate with these changes. Lumbar fusion should be considered in some patients who undergo decompressive laminectomy. The efficacy of and unequivocal indications for lumbar fusion can only be determined from randomized, prospective, controlled trials, however, and these studies have not yet been undertaken.