Duration of indwelling drain following instrumented posterolateral fusion of the lumbar spine does not predict surgical site infection requiring reoperation

The objective of this study was to determine the incidence and predictors of reoperation for surgical site infections (SSI) among patients whose lumbar, closed wound suction drains were removed in the inpatient setting prior to hospital discharge (pre-discharge cohort) versus after inpatient discharge during the first follow up visit (post-discharge cohort). All patients who were admitted for first-time, posterolateral decompression and fusion for degenerative lumbar spine disease were retrospectively reviewed at a single institution. In order to eliminate biases, neither the pre-discharge nor post-discharge cohorts experienced any intra-/postoperative sentinel events other than the primary outcome measure: reoperation for SSI. Of 209 patients in the pre-discharge (n=130) and post-discharge (n=79) cohorts, 15 patients required reoperation for SSI. Although time to drain discontinuation was significantly longer in the post-discharge (8.28days) than the pre-discharge (4.65days) cohorts (p\u3c0.001), the incidences of reoperation for SSI did not significantly differ (6.33 vs 7.69%, respectively, p=0.711). In a multivariable regression, only smoking (OR=5.75, p=0.007) and depression (OR=4.11, p=0.040) predicted reoperation for SSI. Neither time to drain removal nor setting of drain removal was a predictor of reoperation for SSI. Although time to drain discontinuation was expectedly longer in the post-discharge versus pre-discharge cohorts, the incidences of reoperation for SSI did not significantly differ. Neither time to drain removal nor setting of drain removal predicted reoperation for SSI. These results suggest that patients may be safely discharged from the hospital with the surgical drain in place

Preoperative motor strength and time to surgery are the most important predictors of improvement in foot drop due to degenerative lumbar disease

OBJECTIVE: Palsy of dorsiflexion, or foot drop, may be due to degenerative lumbar disease and amenable to posterior spinal decompression. The objective of this study is to measure prognostic factors of and time to foot drop improvement after posterior lumbar decompression. METHODS: We retrospectively reviewed 71 patients undergoing first-time, posterior lumbar decompression for foot drop due to degenerative spinal disease. Patient sex, age, comorbidities (Charlson Comorbidity Index), preoperative anterior tibialis strength (manual muscle testing, MMT), and duration of foot drop were ascertained from clinical notes. Prognostic factors affecting foot drop improvement were calculated with a discrete time proportional hazards model, in which follow-up times and outcome measures were binned into six time intervals: 1 week, 6 weeks, 3 months, 6 months, 1 year, and ≥ 1 year. RESULTS: Of the 71 patients, the mean age was 54.6 ± 16.0 years, and 66.2% (n=47) were males. The mean Charlson Comorbidity Index was 2.42. During a mean follow-up of 30.4 months, dorsiflexion function improved postoperatively in 73.2% (n=52) of patients. The median time to surgery from onset of foot drop was within 6 weeks, and the median preoperative MMT strength of patients with foot drop improvement was 3. Following a discrete-time proportional hazards model, duration of anterior tibialis palsy (HR=0.67, P=0.004) and preoperative muscle strength (HR=1.10, P=0.010) were significant predictors of foot drop improvement. Following an adjusted Kaplan-Meier analysis, the median time to foot drop improvement was within 6 weeks of surgical intervention. CONCLUSIONS: Preoperative muscle strength and palsy duration were statistically significant predictors of foot drop improvement. Furthermore, the median time to improvement was 6 weeks

rhBMP-2 protects against reoperation for pseudoarthrosis and/or instrumentation failure: A matched case-control study of 448 patients

The objective of this independent study is to determine the impact of recombinant human bone morphogenetic protein 2 (rhBMP-2) on reoperation for pseudarthrosis and/or instrumentation failure. A nested case-control study of first-time posterolateral, instrumented fusion of the lumbar spine for degenerative spinal disease was undertaken. Cases of reoperation for pseudoarthrosis and/or instrumentation failure were assigned to controls, who did not experience the primary outcome measure at the time of reoperation. Cases and controls were matched on number of interspaces fused and inclusion of interbody. Predictors of reoperation for pseudoarthrosis and/or instrumentation failure were assessed with a conditional logistical regression controlling for rhBMP-2, age, obesity, and smoking. Of the 448 patients, 155 cases of reoperation for pseudoarthrosis and/or instrumentation were matched with 293 controls. Twenty-six percent of first-time surgeries included rhBMP-2, which was statistically more commonly used in the control cohort (33.11%) versus the case cohort (12.90%) (Unadjusted odds ratio [ORunadj]=0.28) (95% confidence interval [CI]: 0.16-0.49). Following a multivariate analysis controlling for age, obesity, and smoking, the rhBMP-2 recipients incurred a 73% lower odds of reoperation for pseudoarthrosis and/or instrumentation failure (95% CI, 0.15-0.48). Neither sarcomatous nor osseous neoplasm was detected in the study population. Mean follow up did not differ between the cases (81.57±standard deviation [SD] 4.98months) versus controls (74.75±2.49month) (ORunadj=1.01) (95% CI: 1.00-1.01). rhBMP-2 in lumbar fusion constructs protects against reoperation for pseudoarthrosis and/or instrumentation failure. However, the decision to include fusion supplements should be weighted between surgical determinants and clinical outcomes

The incidence of adjacent segment disease after lumbar discectomy: A study of 751 patients

INTRODUCTION: The objective of this study is to determine the incidence and prognostic factors of adjacent segment disease (ASD) following first-time lumbar discectomy (LD). METHODS: We retrospectively reviewed all neurosurgical patients who underwent first-time LD for degenerative lumbar disease from 1990 to 2012. ASD was defined as a clinical and radiographic progression of degenerative spinal disease that required surgical decompression (with or without fusion) at the level above or below the index discectomy. Adjusted odds ratios were calculated from multivariable logistical regression controlling for sex and age, as well as postoperative sensory deficit, motor deficit, back pain, neurogenic claudication, and radiculopathy. RESULTS: Of the 751 patients who underwent single-level LD, the cumulative reoperation rate for degenerative spinal disease was 10.79%. The incidence of ASD requiring reoperation was 4% over 3.11years. More specifically, the incidence of adjacent level discectomy was 1.86% over 3.45years. The annualized reoperation rate for ASD was 1.35% (1.35 ASD reoperations per 100 person-years). The 63.33% incidence of cranial ASD requiring reoperation was statistically significantly higher than the 40.00% incidence of caudal ASD requiring reoperation. Following multivariable logistical regression, the strongest (and only) statistically significant predictor of ASD requiring reoperation was lower extremity radiculopathy after the index discectomy operation (OR=14.23, p\u3c0.001). CONCLUSIONS: In the first series on ASD following first-time LD without fusion, the rate of reoperation for ASD was 4% and the cumulative reoperation rate 10.79%. Rostral ASD is more common than caudal ASD and lower extremity radiculopathy is the strongest predictor of ASD

The Effect of Smoking Status on Successful Arthrodesis After Lumbar Instrumentation Supplemented with rhBMP-2.

OBJECTIVE: The primary objective of this study is to examine the effects smoking status on rhBMP-2 supplementation in spinal fusion constructs. METHODS: Patient records were reviewed retrospectively for a consecutive set of patients who underwent first-time posterolateral, instrumented fusion of the lumbar spine for degenerative spinal disease. All operations included arthrodesis supplementation with rhBMP-2. All patients were followed for at least 2 years. The primary endpoint of this study was reoperation for pseudarthrosis, instrumentation failure, or adjacent segment disease. After a rigorous sensitivity analysis, the measure of association was calculated with a multivariable logistic regression controlling for smoking, age, and number of spinal levels fused. RESULTS: Of the 110 patients in the study population, 82 (74.6%) were nonsmokers and 28 (25.5%) were smokers. Among perioperative predictors, smokers were younger in age (53.9 ± 9.6 vs. 61.1 ± 13.1 years; P = 0.008) and had shorter length of inpatient hospital stay (4.1 ± 1.8 vs. 5.3 ± 3.0; P = 0.039). After a mean follow-up of 59 months, the 32% incidence of reoperation for pseudarthrosis, instrumentation failure, or adjacent segment among smokers was statistically significantly higher than the 13.4% incidence in nonsmokers (P = 0.027). Following multivariable logistic regression, the odds of reoperation among smokers was 4.75-fold higher than for nonsmokers (P = 0.009; 95% confidence interval, 1.48-15.24). CONCLUSIONS: While rhBMP-2 supplements arthrodesis of instrumented lumbar fusion constructs, smoking status ascertains the strongest predictor of reoperation for pseudarthrosis, instrumentation failure, and adjacent segment

The Effect of Smoking Status on Successful Arthrodesis After Lumbar Instrumentation Supplemented with rhBMP-2

OBJECTIVE: The primary objective of this study is to examine the effects smoking status on rhBMP-2 supplementation in spinal fusion constructs. METHODS: Patient records were reviewed retrospectively for a consecutive set of patients who underwent first-time posterolateral, instrumented fusion of the lumbar spine for degenerative spinal disease. All operations included arthrodesis supplementation with rhBMP-2. All patients were followed for at least 2 years. The primary endpoint of this study was reoperation for pseudarthrosis, instrumentation failure, or adjacent segment disease. After a rigorous sensitivity analysis, the measure of association was calculated with a multivariable logistic regression controlling for smoking, age, and number of spinal levels fused. RESULTS: Of the 110 patients in the study population, 82 (74.6%) were nonsmokers and 28 (25.5%) were smokers. Among perioperative predictors, smokers were younger in age (53.9 ± 9.6 vs. 61.1 ± 13.1 years; P = 0.008) and had shorter length of inpatient hospital stay (4.1 ± 1.8 vs. 5.3 ± 3.0; P = 0.039). After a mean follow-up of 59 months, the 32% incidence of reoperation for pseudarthrosis, instrumentation failure, or adjacent segment among smokers was statistically significantly higher than the 13.4% incidence in nonsmokers (P = 0.027). Following multivariable logistic regression, the odds of reoperation among smokers was 4.75-fold higher than for nonsmokers (P = 0.009; 95% confidence interval, 1.48-15.24). CONCLUSIONS: While rhBMP-2 supplements arthrodesis of instrumented lumbar fusion constructs, smoking status ascertains the strongest predictor of reoperation for pseudarthrosis, instrumentation failure, and adjacent segment