Predictors of functional outcome in elderly patients undergoing posterior lumbar spine surgery

Effect of Lower Extremity Osteoarthritis on Outcomes of Lumbar Decompression

BACKGROUND

The purpose of this study is to evaluate how hip or knee osteoarthritis (OA) and total joint arthroplasty impact the outcomes of patients undergoing lumbar decompression.

METHODS

A retrospective review of 342 patients undergoing lumbar decompression without fusion from January 2019 and June 2021 at a single institution was performed. Univariate and multivariate analyses were used to compare outcomes between patients with and without concomitant hip or knee OA.

RESULTS

Forty-six percent of patients had a hip or knee OA diagnosis and were higher risk as they were older, had higher BMIs, were more likely to be former smokers, had higher ASA scores, and were more likely to undergo 3+ level surgery. Postoperatively, after adjusting for differences between groups, hip or knee OA patients were more likely to be readmitted (OR=12.45, p=0.026) or have a complication (OR=13.77, p=0.031). However, patient reported outcomes as measured by Patient Reported Outcomes Measurement Information System-physical function. were similar at 1-3 months and 3-6 months. Higher levels of physical function were observed at 3-6 months postoperatively in hip OA patients with a history of THA.

CONCLUSION

Patients with concomitant hip or knee OA are at higher risk for readmission and postoperative complications but may achieve similar levels of physical function as those without OA.

Developing a Prediction Model for Identification of Distinct Perioperative Clinical Stages in Spine Surgery With Smartphone-Based Mobility Data

BACKGROUND

Spine surgery outcomes assessment currently relies on patient-reported outcome measures, which satisfy established reliability and validity criteria, but are limited by the inherently subjective and discrete nature of data collection. Physical activity measured from smartphones offers a new data source to assess postoperative functional outcomes in a more objective and continuous manner.

OBJECTIVE

To present a methodology to characterize preoperative mobility and gauge the impact of surgical intervention using objective activity data garnered from smartphone-based accelerometers.

METHODS

Smartphone mobility data from 14 patients who underwent elective lumbar decompressive surgery were obtained. A time series analysis was conducted on the number of steps per day across a 2-year perioperative period. Five distinct clinical stages were identified using a data-driven approach and were validated with clinical documentation.

RESULTS

Preoperative presentation was correctly classified as either a chronic or acute mobility decline in 92% of patients, with a mean onset of acute decline of 11.8 ± 2.9 weeks before surgery. Postoperative recovery duration demonstrated wide variability, ranging from 5.6 to 29.4 weeks (mean: 20.6 ± 4.9 weeks). Seventy-nine percentage of patients ultimately achieved a full recovery, associated with an 80% ± 33% improvement in daily steps compared with each patient's preoperative baseline (P = .002). Two patients subsequently experienced a secondary decline in mobility, which was consistent with clinical history.

CONCLUSION

The perioperative clinical course of patients undergoing spine surgery was systematically classified using smartphone-based mobility data. Our findings highlight the potential utility of such data in a novel quantitative and longitudinal surgical outcome measure.

Which functional outcome parameters correlate better with elderly patients' satisfaction after non-fusion lumbar spine surgery?

BACKGROUND

Elderly patients are increasingly operated for spinal degenerative diseases. The treatment objective is quality of life, which, in this population, is difficult to assess. Hence, patient satisfaction, although less objective, is of high importance. In this study, we have examined the relation of various functional parameters after non-fusion spinal surgery, with patient satisfaction.

METHODS

A 5-year follow-up after non-fusion lumbar spine surgery on 185 elderly patients was performed. Demographics, co-morbidity factors, type of lesion and operation performed were recorded. The Oswestry Disability Index (ODI) was calculated. Also, walking distance, use of analgesics, daily activities, social life and patient mobility were assessed by means of study-specific stratified pain-independent questionnaires. Finally, patient satisfaction was assessed by the single-item satisfaction question.

RESULTS

Postoperative ODI, and the improvement regarding ODI, analgesic use and walking distance indices were independent factors influencing patient satisfaction. The insertion of pain analog scale score into this model altered the results, and along with this score, only the walking distance improvement remained an independent statistically significant factor. When the independent from pain scales were used, the improvement of the walking distance score were independently related to the satisfaction of the elderly.

CONCLUSIONS

ODI is applicable in elderly patients, even with the exception of some of the categories assessed. Walking capacity should be assessed separately from other pain-dependent activities; its improvement should be an independent goal of lumbar spine surgery in the elderly. The level of the elderly patient subjectivity in auto-assessing the outcome of lumbar spine surgery is high, and objective outcome measurements remain important.

Clinical and neuropsychiatric correlates of lumbar spinal surgery in older adults: results of a pilot study

AIM

To improve selection of older lumbar surgical candidates, we surveyed correlates of functioning and satisfaction with surgery.

MATERIALS & METHODS

Prospective sample at lumbar spine surgery clinic. Patients (n = 48) were evaluated before surgery and after 3 months. Dependent variables were functioning and surgical satisfaction.

RESULTS

Baseline variables associated with disability at 3 months included cognitive status and widespread pain. There was clinically significant improvement with moderate effects sizes for anxiety and depression at follow-up. Patients with at least a 30% improvement in disability had better physical health-related quality of life and were less likely to report widespread pain before surgery.

CONCLUSION

Although preliminary, two novel potential predictors of lumbar surgery outcome include diminished cognitive functioning and widespread pain. Further study of these variables on post-surgical functioning and satisfaction may improve patient selection.

The safety profile of lumbar spinal surgery in elderly patients 85 years and older

OBJECT

The aging of the population will require that surgeons increasingly consider operating on elderly patients. Performing surgery safely in the elderly will require an understanding of the factors that predict successful outcomes and avoid complications.

METHODS

Records of patients 85 years and older undergoing elective lumbar spinal surgery were retrospectively reviewed. Microdiscectomies were excluded. Preexisting medical illnesses measured using the Charlson Comorbidity Index (CCI), American Society of Anesthesiologists (ASA) Physical Status class, age, and surgical parameters were analyzed as factors potentially predictive of complications. Ambulatory function was rated on a 4-point scale.

RESULTS

During the study 26 consecutive patients (mean age 87 years) with a mean ASA class of 2.6 ± 0.65 and CCI of 1.1 ± 1.27 were enrolled. The average number of levels treated was 2.17 ± 1.23, and 73% underwent fusion. The mean follow-up was 41.9 months with a minimum of 24 months, and all patients were alive at last follow-up. Average blood loss was 142 ± 184 ml, and the operative time was 183.3 ± 80.6 minutes. The mean number of levels treated was 2.17 ± 1.13 (range 1–4). Ambulatory function improved significantly by 0.59 ± 1.0 points. Five complications (19.2%) occurred in 4 patients, 2 major and 3 minor. Four complications were temporary and 1 was permanent. Patient age, blood loss, CCI score, ASA class, the number of levels treated, and fusion surgery were not statistically associated with a complication. Operative time of longer than 180 minutes (p = 0.0134) was associated with complications.

CONCLUSIONS

Lumbar spine surgery in patients 85 years and older can be accomplished safely if careful attention is paid to preoperative selection. Prolonged operative times are associated with a higher risk of complications.

Clinical depression is a strong predictor of poor lumbar fusion outcomes among workers' compensation subjects

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Determine how psychosocial factors, particularly depression, impact lumbar fusion outcomes in a workers' compensation (WC) setting.

SUMMARY OF BACKGROUND DATA

WC patients are less likely to return to work (RTW) after fusion. Few studies evaluate risk factors within this clinically distinct population.

METHODS

A total of 2799 Ohio WC subjects were identified who underwent lumbar fusion between 1993 and 2013 using Current Procedural Terminology (CPT) procedural and International Classification of Diseases, Ninth Revision (ICD-9) diagnosis codes. A total of 123 subjects were diagnosed with depression before fusion. Subjects with a smoking history, prior lumbar surgery, permanent disability, and failed back syndrome were excluded. The primary outcome was whether subjects returned to work within 2 years of fusion and sustained this RTW for more than 6 months of the following year. To determine the impact depression had on RTW status, we performed a multivariate logistic regression analysis. We also compared time absent from work and other secondary outcomes using χ2 and t tests.

RESULTS

Subjects with preoperative depression had significantly higher rates of legal representation, degenerative lumbar disease, and higher medical costs, and used opioid analgesics for considerably longer before and after fusion (P<0.001).Depression group (10.6% [13/123]) and controls (33.0% [884/2676]) met our RTW criteria (P<0.001). Preoperative depression was a negative predictor of RTW status (P<0.001; odds ratio [OR]: 0.38). Additional predictors included working during same week as fusion (OR: 2.15), age more than 50 years (OR: 0.58), chronic preoperative opioid analgesia (OR: 0.58), and legal representation (OR: 0.64). After surgery, depression subjects were absent from work 184 more days compared with controls (P<0.001).

CONCLUSION

Overall, RTW rates after fusion were low, which was especially true for those with pre-existing depression. Depression was a strong negative predictor of postoperative RTW status. Psychological screening and treatment may be beneficial in these subjects. The poor outcomes in this study may highlight a more limited role for fusion among WC subjects with chronic low back pain where RTW is the treatment goal.

LEVEL OF EVIDENCE

3.

Revision lumbar surgery in elderly patients with symptomatic pseudarthrosis, adjacent-segment disease, or same-level recurrent stenosis. Part 2. A cost-effectiveness analysis: clinical article

OBJECT

Despite advances in technology and understanding in spinal physiology, reoperation for symptomatic adjacent-segment disease (ASD), same-level recurrent stenosis, and pseudarthrosis in elderly patients continues to occur. While revision lumbar surgery is effective, attention has turned to questions on the utility and value of the revision decompression and fusion procedure. To date, an analysis of the cost and health state gain associated with revision lumbar surgery in elderly patients with symptomatic pseudarthrosis, ASD, or same-level recurrent lumbar stenosis has yet to be performed. The aim of this study was to assess the long-term outcomes and cost-effectiveness of revision surgery in elderly patients with recurrent or persistent back and leg pain.

METHODS

After reviewing their institutional database, the authors found 69 patients 65 years of age and older who had undergone revision decompression and instrumented fusion for back and leg pain associated with pseudarthrosis (17 patients), same-level recurrent stenosis (24 patients), or ASD (28 patients) and included them in this study. Total 2-year back-related medical resource utilization and health state values (quality-adjusted life years [QALYs], calculated from the EQ-5D, the EuroQol-5D health survey, with US valuation) were assessed. Two-year resource use was multiplied by unit costs based on Medicare national allowable payment amounts. The mean total 2-year cost per QALY gained after revision surgery was assessed.

RESULTS

The mean (± standard deviation) time between the index surgery and revision surgery was 3.51 ± 3.63 years. A mean cumulative 2-year gain of 0.35 QALY was observed after revision surgery. The mean total 2-year cost of revision surgery was $28,256 ± $3000 (ASD: $28,829 ± $3812, pseudarthrosis: $28,069 ± $2508, same-level recurrent stenosis: $27,871 ± $2375). Revision decompression and extension of fusion was associated with a mean 2-year cost of $80,594 per QALY gained.

CONCLUSIONS

Revision decompression and fusion provided a significant gain in health state utility for elderly patients with symptomatic pseudarthrosis, same-level recurrent stenosis, or ASD, with a mean 2-year cost of $80,594 per QALY gained. When indicated, revision surgery for symptomatic ASD, same-level recurrent stenosis, and pseudarthrosis is a valuable treatment option for elderly patients experiencing persistent back and leg pain. Findings in this study provided a value measure of surgery that can be compared with future cost-per-QALY-gained studies of medical management or alternative surgical approaches.

Complications and outcomes after spinal deformity surgery in the elderly: review of the existing literature and future directions

Object

The elderly population (age > 60 years) is the fastest-growing age group in the US. Spinal deformity is a major problem affecting the elderly and, therefore, the demand for surgery for spinal deformity is becoming increasingly prevalent in elderly patients. Much of the literature on surgery for adult deformity focuses on patients who are younger than 60 years, and therefore there is limited information about the complications and outcomes of surgery in the elderly population.

In this study, the authors undertook a review of the literature on spinal deformity surgery in patients older than 60 years. The authors discuss their analysis with a focus on outcomes, complications, discrepancies between individual studies, and strategies for complication avoidance.

Methods

A systematic review of the MEDLINE and PubMed databases was performed to identify articles published from 1950 to the present using the following key words: “adult scoliosis surgery” and “adult spine deformity surgery.” Exclusion criteria included patient age younger than 60 years. Data on major Oswestry Disability Index (ODI) scores, visual analog scale (VAS) scores, patient-reported outcomes, and complications were recorded.

Results

Twenty-two articles were obtained and are included in this review. The mean age was 74.2 years, and the mean follow-up period was 3 years. The mean preoperative ODI was 48.6, and the mean postoperative reduction in ODI was 24.1. The mean preoperative VAS score was 7.7 with a mean postoperative decrease of 5.2. There were 311 reported complications for 815 patients (38%) and 5 deaths for 659 patients (< 1%).

Conclusions

Elderly patient outcomes were inconsistent in the published studies. Overall, most elderly patients obtained favorable outcomes with low operative mortality following surgery for adult spinal deformity.

Laminectomy in patients with achondroplasia: the impact of time to surgery on long-term function

STUDY DESIGN

Retrospective analysis, survey.

OBJECTIVE

To describe a cohort of individuals with achondroplasia undergoing thoracolumbar laminectomy and to examine if shorter time to surgery was related to improvement in long-term functional outcome.

SUMMARY OF BACKGROUND DATA

Data on the long-term benefits of laminectomy are mixed for such patients. Earlier intervention may be associated with greater likelihood of long-term benefit, but quantified data are lacking.

METHODS

We retrospectively studied 49 patients with achondroplasia who underwent primary laminectomy for spinal stenosis. Patients completed a questionnaire to assess symptoms, walking distance, and independence (per Modified Rankin Scale), before surgery and currently. Responses were analyzed for the likelihood of improved walking distance or Rankin level.

RESULTS

Our patients had the following mean values: age, 37.7 ± 10.6 years; body mass index, 31.8 ± 5.5; symptom duration, 74.0 ± 100.1 months; preoperative symptom severity score, 2.7 ± 1.0 points; mean changes in blocks walked, +0.39 ± 2.0; and Rankin level, +0.08 ± 1.47. Patients with a time-to-surgery interval of <6 months were 7.13 times (95% confidence interval [CI], 1.39-36.66) more likely to experience improvement in walking distance and 4.00 times (95% CI, 1.05-15.21) more likely to experience Rankin level improvement than patients whose interval was >6 months. Intervals of up to 12 and 24 months were associated with increased likelihoods of 4.95 (95% CI, 1.41-17.41) and 3.43 (95% CI, 1.05-11.22), respectively, of improved walking distance compared with those with longer time-to surgery intervals, but those Rankin level improvements were not statistically significant.

CONCLUSION

Time from symptom onset to surgery in patients with achondroplasia is an important predictor of long-term functional outcome. For sustained long-term postsurgical improvement, the window of opportunity might be relatively narrow. Patients with achondroplasia should seek medical advice for spinal stenotic symptoms as soon as possible.

Predictors of long-term outcome in an elderly group after laminectomy for lumbar stenosis

Object

This is a retrospective long-term outcome study of results after laminectomy for lumbar spinal stenosis in an elderly group of patients. The study was designed to evaluate possible demographic, comorbidity, and clinical prognosticators for pain reduction and functional improvement in this population. Because the assessment of functional outcome in the elderly is complicated by several specific factors, the use of outcome measurement parameters should be revised and refined. Moreover, despite numerous relevant studies, the results of various techniques remain equivocal, particularly among the elderly, which renders the implementation of focused studies necessary. New data could be used to refine patient selection and choice of technique to improve prognosis.

Methods

During a 5-year period, lumbar laminectomies were performed in 182 elderly patients. Of these 182, 125 patients (68.8%) were followed up for a mean period of 60.8 months. The outcome was assessed by means of pain visual analog scale (VAS) pain score, Oswestry Disability Index (ODI), and patient satisfaction questionnaire, and results were correlated to demographic (age, sex), comorbidity (Charlson Comorbidity Index, diabetes, depression, and history of lumbar spine surgery), and clinical (main preoperative complaint, preoperative VAS score, and ODI) factors.

Results

In terms of the VAS score, 106 patients (84.8%) exhibited improvement at follow-up. The corresponding ODI improvement rate was 69.6% (87 patients). The mean VAS and ODI differences were 5.1 and 29.1, respectively. One hundred two patients (81.6%) were satisfied with the results of the operation. Univariate analysis for possible prognostic factors revealed the significant influence of low-back pain on VAS score (p = 0.024) and ODI (p < 0.001) not improving, while the ODI was also affected by sex (females had a poorer outcome [p = 0.019]). In contrast, patient satisfaction was not related to any of the preoperative parameters recorded; nevertheless, it was strongly related to all functional measurements on follow-up.

Conclusions

Considering the methodological issues of such studies, particularly in elderly patients, the authors conclude that the ODI is more sensitive than the VAS score in assessing prognostic value and that patient satisfaction is difficult to prognosticate, underscoring the particularities that this population presents regarding functionality assessment. Considering the prognostic value of preoperative factors, a negative influence of low-back pain and female sex is reported.

National complication rates and disposition after posterior lumbar fusion for acquired spondylolisthesis

STUDY DESIGN

Database study using Nationwide Inpatient Sample (NIS) administrative data from 1993 to 2002.

OBJECTIVE

To determine rates of in-hospital complications and complex disposition for patients undergoing posterior lumbar fusion for degenerative spondylolisthesis, and the association of demographic factors.

SUMMARY OF BACKGROUND DATA

Spondylolisthesis affects primarily elderly populations. Recent data suggests a benefit of surgical treatment for acquired lumbar spondylolisthesis. However, the risks of these procedures, and the impact of patient demographics on risk, have not been nationally quantified.

METHODS

Data from 66,601 patients in the NIS (1993-2002) with diagnostic and procedure codes specifying posterior lumbar fusion for acquired spondylolisthesis were included. Patients were grouped by age, sex, race, number of comorbidities, hospital size, and time period of procedure. Multivariate analysis correlated patient and hospital characteristics with complex disposition and complications.

RESULTS

Mortality rate was 0.15%. Eleven percent of patients had one or more in-hospital complications; overall complication rate was 13 per 100 operations. Hematoma/seroma (5.4 per 100) was the most common complication, followed by pulmonary (2.6), renal (1.8), and cardiac (1.2) complications. Infection and neurologic injury occurred in <1% of patients. Older patients and those with a number of comorbidities had greater rates of in-hospital complication and complex disposition. Compared to those aged 45 to 64, patients aged 65 to 84 were almost 70% more likely to have complications (OR: 1.67) and 5 times as likely to have complex disposition (OR: 5.84). Having 3 or greater comorbidities, compared to no comorbidities, was also associated with increased risk of complication (OR: 1.6) and complex disposition (OR: 2.3).

CONCLUSION

Posterior lumbar fusion for acquired lumbar spondylolisthesis is safe. However, age and comorbidity independently increase in-hospital complications and complex disposition. These data may improve national estimates of surgical risk, patient selection, informed consent, and cost-efficacy analysis for posterior lumbar fusion operations for acquired spondylolisthesis.

Are preoperative health-related quality of life scores predictive of clinical outcomes after lumbar fusion?

STUDY DESIGN

Prospective longitudinal cohort.

OBJECTIVE

This study evaluated the effect of preoperative Mental Component Summary (MCS), preoperative Physical Component Summary (PCS), preoperative Oswestry Disability Index (ODI), back pain predominance, body mass index (BMI), age, smoking status, and workers' compensation on health-related quality of life after lumbar fusion. These factors were selected as they are readily available and may influence a surgeon's decision-making process.

SUMMARY OF BACKGROUND DATA

Measures of health-related quality of life are increasingly used to evaluate treatment effectiveness. However, their use as a predictive tool to determine which patients will improve has been limited.

METHODS

The Short Form 36 (SF-36) and ODI were collected before surgery and two years after surgery in 489 patients undergoing lumbar fusion for degenerative disorders. Linear regression modeling was used to determine the effect of preoperative MCS, preoperative PCS, preoperative ODI, back pain predominance, BMI, age, smoking status, and workers' compensation on the change in ODI and change in SF-36 PCS two years after lumbar fusion.

RESULTS

Patients with better preoperative MCS (P = 0.008) and worse preoperative ODI scores (P < 0.0001) achieved greater ODI improvement. Workers' compensation patients did significantly worse (P = 0.03). Patients with better preoperative MCS (P = 0.0004), better preoperative PCS (P = 0.0155), and worse preoperative ODI scores (P = 0.0210) achieved greater PCS improvement. Those on workers' compensation had lower changes in PCS, an effect that was nearly significant (P = 0.0644). There were no significant correlations between PCS and ODI improvement and back pain predominance, BMI, age, and smoking status. Attempts at determining threshold values for MCS, PCS, and ODI that are predictive of a patient achieving minimum clinically important difference for PCS and ODI were unsuccessful.

CONCLUSION

Patients with good preoperative MCS and poor preoperative ODI scores who are not on workers' compensation are more likely to improve after lumbar fusion. Threshold values for MCS, PCS, and ODI predictive of a patient achieving minimum clinically important difference for PCS and ODI could not be determined.

Union versus nonunion after posterolateral lumbar fusion: a comparison of long-term surgical outcomes in patients with degenerative lumbar spondylolisthesis

It has been reported that in patients undergoing posterolateral lumbar fusion (PLF), the fusion status is not related to the short-term operative results. To determine whether the fusion status influences the long-term operative results of PLF, we retrospectively examined the surgical outcomes of uninstrumented PLF for a minimum of 8 years (average, 9.5 years), by comparing cases exhibiting union with those exhibiting nonunion. Uninstrumented PLF was performed for the treatment of lumbar canal stenosis (LCS) with degenerative spondylolisthesis. Since nine patients were lost to final follow-up, the study included 42 patients, and the follow-up rate was 82.4%. The mean age of the patients was 64.1 years (range 46-77 years). Eight patients exhibited fusion at the L3-4 level and 34 patients, at the L4-5 level. The fusion status was assessed using plain radiographs. The clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scores. Nonunion was noted in 26% (11/42) of the patients. There were no statistically significant differences between the groups exhibiting union and nonunion with respect to age, sex, preoperative JOA score, or preoperative lumbar instability. The union group achieved better operative results than the nonunion group at the 5-year and final follow-up (P = 0.006 and 0.008, respectively) although there was no significant difference in the percent recovery at 1 and 3-year follow-up (P = 0.515 and 0.506, respectively). A stepwise regression analysis revealed that the best combination of predictors for percent recovery at the time of final follow-up included the fusion status and the presence of comorbid disease. The results indicate that the fusion status following PLF is a critical factor influencing the long-term but not short-term operative results in the treatment of LCS with degenerative spondylolisthesis.

Clinical outcomes in older patients after posterolateral lumbar fusion

BACKGROUND CONTEXT

Older patients are often advised that their age is a contraindication to lumbar fusion surgery. There is, however, limited available data to support or contradict this assertion. Although prior studies of surgical treatment for lumbar degenerative disease suggest that older patients obtain symptomatic pain relief, an evaluation of fusion outcomes based on modern Health-Related Quality of Life (HRQOL) measures is lacking.

PURPOSE

The purpose of this study was to document clinical outcomes based on standardized HRQOL measures in patients over 65 years of age treated by lumbar decompression and fusion surgery.

DESIGN/SETTING

This study was a retrospective review of prospectively collected patient reported outcomes data.

PATIENT SAMPLE

Ninety-seven consecutive patients over 65 years of age treated by lumbar decompression and fusion between 2000 and 2004 were enrolled in a prospective health status outcomes protocol. Eighty-five patients (88%) had complete data at a minimum 2-year follow-up.

OUTCOME MEASURES

Medical Outcomes Study Short Form 36v.2 (SF-36), Oswestry Disability Index (ODI), numeric rating scales (NRS) back and leg pain scores.

METHODS

Patients over 65 years of age treated by lumbar fusion were evaluated based on HRQOL measures at a minimum of 2 years postoperatively. Variables including history of prior surgery and occurrence of a perioperative complication were evaluated. A comparison group of patients 50 to 64 years of age was also analyzed.

RESULTS

In patients over 65 years old, mean improvement of 6.21 points in SF-36 Physical Composite Score and 5.75 points in SF-36 Mental Composite Score was observed. There was a mean 16.38-point improvement in ODI, 3.08-point improvement in back pain NRS, and 2.65-point improvement in leg pain NRS. SF-36 subscale scores showed improvement for all parameters except general health, where there was a small but statistically significant decline. There was no difference in outcomes at 2 years postoperatively based on the occurrence of a perioperative complication. Patients undergoing a primary lumbar surgical procedure had consistently better outcomes than patients undergoing a revision procedure.

CONCLUSIONS

The results of this study support the efficacy of lumbar decompression and fusion in selected patients over 65 years of age. Occurrence of a perioperative complication did not adversely affect clinical outcome. Patients undergoing a revision procedure should be counseled with regard to the more limited benefits seen with revision surgery.

Outpatient lumbar spine decompression in 233 patients 65 years of age or older

STUDY DESIGN

A retrospective review including patient follow-up on all lumbar decompression procedures by 1 of 2 surgeons.

OBJECTIVE

To evaluate the success of lumbar decompressions performed on an outpatient basis on patients 65 years of age or older.

SUMMARY OF BACKGROUND DATA

The efficacy of decompression procedures on the lumbar spine is documented and is often performed on an outpatient basis. Few studies have evaluated these procedures in older adults, and none in a greater population of patients on an outpatient basis.

METHODS

A total of 1377 lumbar decompression procedures were performed from 1992 to 2001 by 2 surgeons, 263 of these on patients 65 years of age or older. A chart review was done on all procedures. Follow-ups occurred from June 2001 to August 2003 by an unbiased observer not involved in the surgical procedures.

RESULTS

A total of 30 (11.4%) of the 263 procedures were done with a hospital stay: 10 patients of 243 planned inpatient procedures (4.1%) were converted due to a complication. Of the 233 done on an outpatient basis, 4 (1.7%) had a complication. A total of 152 patients (57.8%) completed a questionnaire by phone or mail by an unbiased observer at least 18 months after surgery. A total of 97 of 134 patients (72.4%) said they would repeat the outpatient procedure, and 94 of 136 patients (69.1%) stated that their surgery's outcome was good or better.

CONCLUSIONS

For the aged patient, surgical decompression of the lumbar spine can be performed on an outpatient basis safely and successfully.

The effect of duration of symptoms on standard outcome measures in the surgical treatment of spinal stenosis

The effect of the duration of symptoms on the outcome of lumbar decompression surgery is not known. The aim of our study was to determine the predictors of functional outcome of lumbar decompression surgery for degenerative spinal stenosis with particular emphasis on the duration of symptoms. In this prospective cohort study, we recruited 100 patients with a full data set available at 1-year and 85% at 2-year follow-ups: 49 females and 51 males with an average age of 62 (range 52-82). The pre- and post-operative outcome measures were Oswestry disability index (ODI), low back outcome score (LBOS), pain visual analogue score (VAS), modified somatic perception (MSP) and modified Zung depression (MZD) score. Dural tear occurred in 14%, and there was one post-operative extra-dural heamatoma. Overall, the ODI improved from a pre-operative of 56 (+/-13) to a 1-year ODI of 40 (+/-22) and at 2-year ODI of 40 (+/-21). The VAS improved from an average of 8 to 5.2 at 1 year and 4.9 at 2 years. There was a statistical significant association between symptom duration and the change in ODI (P=0.007 at 1-year follow-up, P=0.001 at 2-year follow-up), LBOS (P=0.001 at 1-year follow-up, P<0.001 at 2-year follow-up) and VAS (P=0.003 at 1-year follow-up, P=0.001 at 2-year follow-up). Subgroup analyses showed that patients with symptom duration of less than 33 months had a more favourable result. In addition, the patients who rated the operation as excellent had a statistically significantly shorter duration of symptoms. We have not found a predictive value for age at operation, MSP or MZD. The number of levels of decompression and the different types of decompression surgery did not influence the surgical results. Our study indicates that the symptom duration of more than 33 months has a less favourable functional outcome.

A novel method for the quantitative evaluation of lumbar spinal stenosis

STUDY DESIGN

A retrospective study of computed tomography (CT) myelographic images in patients with degenerative lumbar spinal stenosis (LSS).

OBJECTIVES

To introduce a new technique for the quantitative evaluation of LSS.

BACKGROUND

Advances in hardware and software technology now permit inexpensive digitalization of radiological images, and enable methodologies for quantifying space available for neural elements in spinal canal. However, a valid method with quantitative evaluation of spinal stenosis in living patients has not been developed yet.

METHODS AND MATERIALS

Preoperative CT myelographic scans of 50 patients with degenerative LSS were collected for retrospective investigation. The patients subsequently underwent lumbar decompressive surgery. They included scans from thoracic vertebra 12 (T12) to sacrum (S1), in which each segment was scanned through both the vertebral body and disk. All CT scan films were digitized using a high-resolution digital camera. ImageTool software was used to measure three parameters: cross-sectional area of dural sac at disk level (A), cross-sectional area of spinal canal at midpedicular level (B), and cross-sectional area of vertebral body (C). The dural sac canal ratio (DSCR) was calculated as A/B x 100%. Low DSCR implied severe dural sac compression with a high degree of stenosis. The spinal canal vertebral ratio (CVR) was also calculated as B/C x 100%. Low CVR implied a low baseline of canal capacity for neural elements. They were calculated from T12 to S1.

RESULTS

The study consisted of 26 male and 24 female patients, with an average age of 68.4 (35-97) years. A total of 295 segments were evaluated, of which 118 (40%) were surgically decompressed. There were wide ranges of canal cross-sectional areas (140-475 mm(2)) and dural sac cross-sectional area (54-435 mm(2)). Male patients had a slightly larger canal cross-sectional area than female patients at each level. The mean CVR was found decreased from T12 (26.1%) to L4 (18.3%). This was higher in female than in male patients, especially from T12 to L2 (P < 0.01). There were significant correlations between spinal canal and dural sac cross-sectional area (r = 0.55, P < 0.001), and also between CVR and DSCR (r = 0.31, P < 0.001). Of the levels decompressed, 82% was performed from the level L2 to L5, in which there was no significant difference in canal cross-sectional area and CVR between decompression and nondecompression (P > 0.05). There was a good correspondence between decreasing mean DSCR and increasing percentile of levels decompressed.

CONCLUSION

DSCR represents a useful method for the quantitative diagnosis of lumbar spinal canal stenosis. ImageTool software is a useful tool in measuring spinal morphometry.

Five-year outcomes of surgical treatment for degenerative lumbar spinal stenosis: a prospective observational study of symptom severity at standard intervals after surgery

STUDY DESIGN

A prospective observational study of patients undergoing surgery for degenerative lumbar spinal stenosis.

OBJECTIVE

To determine whether the long-term outcomes differ as a function of age and gender.

SUMMARY OF BACKGROUND DATA

The long-term results of surgery for lumbar spinal stenosis are not well understood, and the patient characteristics that predispose patients to worse outcomes are unknown.

METHODS

Seventy patients who underwent decompressive laminotomy with or without arthrodesis for degenerative lumbar spinal stenosis were prospectively studied at standard intervals after surgery with respect to symptom severity rated on a visual analog scale (VAS).

RESULTS

The VAS scores for younger patients improved steadily for 3 or 6 months, after which the improvement was maintained until 60 months. The VAS scores for older patients showed a similar time course until 36 months, after which the VAS scores were worse compared with those for younger patients. The VAS scores for females were worse than those for males, in three symptoms queried, at one or more of the evaluation time points.

CONCLUSION

In patients undergoing surgery for degenerative lumbar spinal stenosis, older age predicts a greater risk of late recurrence of symptoms, and women have higher VAS scores than men after surgery.

Predictors of outcomes of percutaneous vertebroplasty for osteoporotic vertebral fractures

STUDY DESIGN

Retrospective review of all percutaneous vertebroplasties performed in the authors' institution from November 1994 to June 2002. OBJECTIVE.: To determine the factors affecting the outcome of percutaneous vertebroplasty for the treatment of persistent painful osteoporotic fractures.

SUMMARY OF BACKGROUND DATA

Percutaneous vertebroplasty is an efficient procedure to treat pain due to osteoporotic vertebral fracture. However, the patient population that is most likely to benefit from this procedure is uncertain, and the inclusion and exclusion criteria for an ideal candidate have varied widely in the literature.

METHODS

A retrospective review of 278 percutaneous vertebroplasty procedures for osteoporotic fractures at 423 levels was performed. Sociodemographic, clinical, radiologic, and procedural data were analyzed as parameters for prognosis significance by univariate and multivariate analysis with logistic regression to estimate the strength of influence of each variable.

RESULTS

The presence of two or less symptomatic vertebrae (P < 0.03), the American Society of Anesthesiologists status I (P < 0.001), the presence of signal changes on magnetic resonance imaging (P < 0001), and the collapse of the vertebral body less than 70% (P < 0.001) were assessed as parameters for prognostic significance. Multivariate analysis also showed a significant correlation between the American Society of Anesthesiologists score and height loss of the vertebral body and the final outcome. The presence of signal changes on magnetic resonance imaging showed the highest odds ratio adjusted.

CONCLUSIONS

Appropriate patient selection is essential for achieving clinical success. Better results can be expected in patients with an American Society of Anesthesiologists score of I and when the level managed is confirmed by magnetic resonance imaging and the vertebral body height loss is less than 70%.

Assessing observational studies of spinal fusion and chemonucleolysis

STUDY DESIGN

Literature review and survey of spine surgeons.

OBJECTIVES

To identify reasons for variation in results among observational studies of spinal surgery.

SUMMARY AND BACKGROUND DATA

Orthopedic treatments are often evaluated by observational studies rather than randomized controlled trials. The value of observational studies is debated.

METHODS

A literature search was performed to find several observational studies that compared the same spinal surgeries. Possible confounders for these studies were identified by a survey of spinal surgeons. Study characteristics from these articles were tested for an association with study results.

RESULTS

Most observational studies were case series. Articles studied in depth included 20 evaluating chemonucleolysis and 14 evaluating spinal arthrodesis for patients who had herniated disc or spinal stenosis. For each treatment comparison, results varied from strongly favoring one treatment to strongly favoring the other. Apparent causes of the variation were patient selection criteria, the choice of outcome measure, and follow-up rate. Few studies reported on the potential confounders identified by physician surveys, and only one study used statistical methods to reduce the influence of confounding.

CONCLUSIONS

The results suggest that review of several comparable observational studies may help evaluate treatment, identify patient types most likely to benefit from a give treatment, and provide information about study features that can improve the design of subsequent observational or randomized controlled studies. The potential of comparative observational studies has not been realized because of current inadequacies in their design, analysis, and reporting.

Complications associated with lumbar stenosis surgery in patients older than 75 years of age

OBJECT

An aging population will require that surgeons increasingly consider operative intervention in elderly patients. To perform this surgery safely will require an understanding of the factors that predict successful outcomes as well as complications.

METHODS

Records of patients older than the age of 75 years who underwent lumbar spinal stenosis surgery were retrospectively reviewed. Preexisting medical illnesses were analyzed using the Charlson Weighted Comorbidity Index. Ambulatory function was rated on a four-point scale. Statistical analysis was performed using a one-tailed t-test with unpaired variance. Eighty-eight patients treated between 1994 and 2001 were identified. Forty-five percent were women and 52 patients underwent spinal fusion. The follow-up period averaged 21 months. Back pain was present preoperatively in 89%; after surgery 43% experienced complete relief and 33% partial improvement. Leg pain was present preoperatively in 98%; after surgery 43% experienced complete relief and 42% partial improvement. Of the 33 patients with preoperative gait disturbances, 61% improved at least one point on the ambulatory scale. Wound complications and systemic complications were demonstrated in 24 and 16 patients, respectively. There were no deaths. Age (p = 0.322), number of fused levels (p = 0.371), and the number of laminectomy levels (p = 0.254) were not predictive of complications. Length of operative time (p = 0.003) and the Charlson Weighted Comorbidity Index score (p = 0.088) were associated with both systemic and wound complications.

CONCLUSIONS

Surgery in patients older than age 75 years can be conducted safely and with similar outcome rates as in younger patients. The Charlson Weighted Comorbidity Index score and operative time were predictive of the risk of complications.