Predictors of Oswestry Disability Index worsening after lumbar fusion

Effects of Preoperative Use of Povidone-Iodine-Impregnated Dressing on Postoperative Rate of Surgical Site Infection in Patients Undergoing Posterolateral Lumbar Spinal Fusion Surgery: A Randomized, Nonblinded, Active-Controlled Trial

BACKGROUND AND OBJECTIVES

No study has evaluated the efficacy of using preoperative antiseptic dressings in reducing the rate of surgical site infection (SSI) in spine surgery thus far. To investigate the efficacy of the use of preoperative povidone-iodine-impregnated antiseptic dressings in patients undergoing instrumented posterolateral lumbar spinal fusion.

METHODS

This was a randomized, nonblinded, active-controlled, parallel-group clinical trial. Patients were randomly assigned to the 2 study groups, including treatment and control. Patients in the treatment group received povidone-iodine-impregnated antiseptic dressing applied to the anticipated incision site 12 hours before the operation. The control group merely received the standard perioperative care with no additional intervention or placebo. Patients were followed up for 90 days, and SSIs were recorded.

RESULTS

A total of 200 patients were included in this study (100 in each arm). Three cases of SSI were observed in the treatment group compared with 12 in the control one. A significant reduction in the postoperative rate of SSI was observed in the treatment group compared with the control one (P = .029). In addition to study intervention (P = .029), body mass index (P = .005), smoking status (P = .005), duration of the procedure (P = .003), American Society of Anesthesiologists class (P = .002), and diabetes mellitus (P < .001) were significantly associated with the postoperative rate of SSI.

CONCLUSION

To the best of our knowledge, this study for the first time showed that preoperative use of antiseptic dressings is significantly effective in reducing the rate of SSI in instrumented posterior lumbar spinal fusion surgery. Future studies are warranted to evaluate the efficacy of different preparations or the effectiveness of the present one in patients undergoing spine procedures with other surgical characteristics.

Poor muscle health and low preoperative ODI are independent predictors for slower achievement of MCID after minimally invasive decompression

BACKGROUND CONTEXT

Although some previous studies have analyzed predictors of nonimprovement, most of these have focused on demographic and clinical variables and have not accounted for radiological predictors. In addition, while several studies have examined the degree of improvement after decompression, there is less data on the rate of improvement.

PURPOSE

To identify the risk factors and predictors (both radiological and nonradiological) for slower as well as nonachievement of minimal clinically important difference (MCID) after minimally invasive decompression.

DESIGN

Retrospective cohort.

PATIENT SAMPLE

Patients who underwent minimally invasive decompression for degenerative lumbar spine conditions and had a minimum of 1-year follow up were included. Patients with preoperative Oswestry Disability Index (ODI) <20 were excluded.

OUTCOME MEASURE

MCID achievement in ODI (cut off 12.8).

METHODS

Patients were stratified into two groups (achieved MCID, did not achieve MCID) at two timepoints (early ≤3 months, late ≥6 months). Nonradiological (age, gender, BMI, comorbidities, anxiety, depression, number of levels operated, preoperative ODI, preoperative back pain) and radiological (MRI - Schizas grading for stenosis, dural sac cross-sectional area, Pfirrmann grading for disc degeneration, psoas cross-sectional area and Goutallier grading, facet cyst/effusion; X-ray - spondylolisthesis, lumbar lordosis, spinopelvic parameters) variables were assessed with comparative analysis to identify risk factors and with multiple regression models to identify predictors for slower achievement of MCID (MCID not achieved by ≤3 months) and nonachievement of MCID (MCID not achieved at ≥6 months).

RESULTS

A total of 338 patients were included. At ≤3 months, patients who did not achieve MCID had significantly lower preoperative ODI (40.1 vs 48.1, p<0.001) and worse psoas Goutallier grading (p=.048). At ≥6 months, patients who did not achieve MCID had significantly lower preoperative ODI (38 vs 47.5, p<.001), higher age (68 vs 63 years, p=.007), worse average L1-S1 Pfirrmann grading (3.5 vs 3.2, p=.035), and higher rate of pre-existing spondylolisthesis at the operated level (p=.047). When these and other probable risk factors were put into a regression model, low preoperative ODI (p=.002) and poor Goutallier grading (p=.042) at the early timepoint and low preoperative ODI (p<.001) at the late timepoint came out as independent predictors for MCID nonachievement.

CONCLUSION

After minimally invasive decompression, low preoperative ODI and poor muscle health are risk factors and predictors for slower achievement of MCID. For nonachievement of MCID, low preoperative ODI, higher age, greater disc degeneration, and spondylolisthesis are risk factors and low preoperative ODI is the only independent predictor.

Does Preoperative Symptom Duration Impact Clinical Outcomes After Minimally Invasive Transforaminal Lumbar Interbody Fusion in the Ambulatory Setting?

BACKGROUND

The effect of prolonged symptom duration in patients undergoing ambulatory MIS-TLIF on postoperative clinical outcomes has not been well studied. We aim to compare symptom duration of pain and/or weakness on postoperative outcomes in patients undergoing outpatient MIS-TLIF.

METHODS

Patients undergoing outpatient MIS-TLIF were gathered in a single-surgeon database. Exclusion criteria were patients missing onset of symptoms, date of surgery, or diagnosis of malignancy, trauma, or infection. Patients were grouped by symptoms <1 year or symptoms ≥1 year. Propensity score matching for demographics was utilized. Minimal clinically important difference (MCID) achievement was calculated by comparing change in patient-reported outcome measures (PROMs) to previously established values. Inferential statistics for demographics, perioperative characteristics, PROMs, and MCID were utilized to compare between groups and/or postoperative improvement.

RESULTS

After matching, there were a total of 56 patients, with 30 patients with symptoms <1-year. The <1-year cohort reported significant improvement in all time points in VAS back/leg and 12-week/6-months in ODI. The ≥1-year cohort demonstrated significant improvement in 6-month Patient-Reported Outcomes Measurement-Information System Physical Function, 6-week to 1-year VAS back, 6-week VAS leg, and 6-month ODI. The <1-year cohort had higher MCID attainment rates in 1-year VAS back/leg.

CONCLUSIONS

Independent of symptom duration, patients reported significant improvement in back pain at all postoperative periods. Patients presenting with shorter symptom duration consistently reported significant improvement in leg pain postoperatively. Patients with shorter symptom duration demonstrated greater MCID achievement in back and leg pain. Patients indicated for outpatient MIS-TLIF may benefit more from earlier intervention following onset of symptoms.

Development and Internal Validation of Supervised Machine Learning Algorithms for Predicting the Risk of Surgical Site Infection Following Minimally Invasive Transforaminal Lumbar Interbody Fusion

Purpose: Machine Learning (ML) is rapidly growing in capability and is increasingly applied to model outcomes and complications in medicine. Surgical site infections (SSI) are a common post-operative complication in spinal surgery. This study aimed to develop and validate supervised ML algorithms for predicting the risk of SSI following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

Methods: This single-central retrospective study included a total of 705 cases between May 2012 and October 2019. Data of patients who underwent MIS-TLIF was extracted by the electronic medical record system. The patient's clinical characteristics, surgery-related parameters, and routine laboratory tests were collected. Stepwise logistic regression analyses were used to screen and identify potential predictors for SSI. Then, these factors were imported into six ML algorithms, including k-Nearest Neighbor (KNN), Decision Tree (DT), Support Vector Machine (SVM), Random Forest (RF), Multi-Layer Perceptron (MLP), and Naïve Bayes (NB), to develop a prediction model for predicting the risk of SSI following MIS-TLIF under Quadrant channel. During the training process, 10-fold cross-validation was used for validation. Indices like the area under the receiver operating characteristic (AUC), sensitivity, specificity, and accuracy (ACC) were reported to test the performance of ML models.

Results: Among the 705 patients, SSI occurred in 33 patients (4.68%). The stepwise logistic regression analyses showed that pre-operative glycated hemoglobin A1c (HbA1c), estimated blood loss (EBL), pre-operative albumin, body mass index (BMI), and age were potential predictors of SSI. In predicting SSI, six ML models posted an average AUC of 0.60–0.80 and an ACC of 0.80–0.95, with the NB model standing out, registering an average AUC and an ACC of 0.78 and 0.90. Then, the feature importance of the NB model was reported.

Conclusions: ML algorithms are impressive tools in clinical decision-making, which can achieve satisfactory prediction of SSI with the NB model performing the best. The NB model may help access the risk of SSI following MIS-TLIF and facilitate clinical decision-making. However, future external validation is needed.

Surgical Site Infection Following Primary Definitive Fusion for Pediatric Spinal Deformity: A Multicenter Study of Rates, Risk Factors, and Pathogens

STUDY DESIGN

A retrospective multicenter study.

OBJECTIVE

To determine the surgical site infection (SSI) rate, associated risk factors, and causative pathogens in pediatric patients with spinal deformity.

SUMMARY OF BACKGROUND DATA

There have been no extensive investigations of the risk factors for SSI in Japan.

METHODS

Demographic data, radiographic findings, and the incidence of SSI were retrospectively analyzed in 1449 pediatric patients who underwent primary definitive fusion surgery for spinal deformity at any of 15 institutions from 2015 to 2017. SSI was defined according to the US Centers for Disease Control and Prevention guideline.

RESULTS

The incidence of all SSIs was 1.4% and that of deep SSIs was 0.76%. The most common pathogenic microbes were methicillin-resistant staphylococci (n = 5) followed by gram-negative rods (n = 4), methicillin-sensitive staphylococci (n = 1), and others (n = 10). In univariate analysis, younger age, male sex, a diagnosis of kyphosis, type of scoliosis, American Society of Anesthesiologists (ASA) class ≥3, mental retardation urinary incontinence, combined anterior-posterior fusion, greater magnitude of kyphosis, three-column osteotomy, use of blood transfusion, and number of antibiotic administration were associated with the likelihood of SSI (all P < 0.05). Multivariate logistic regression analysis identified the following independent risk factors for SSI: syndromic scoliosis etiology (vs. idiopathic scoliosis; adjusted odds ratio [OR] 16.106; 95% confidence interval [CI] 2.225-116.602), neuromuscular scoliosis etiology (vs. idiopathic scoliosis; adjusted OR 11.814; 95% CI 1.109-125.805), ASA class 3 (vs. class 2; adjusted OR 15.231; 95% CI 1.201-193.178), and administration of antibiotic therapy twice daily (vs. three times daily; adjusted OR 6.121; 95% CI 1.261-29.718).

CONCLUSION

The overall infection rate was low. The most common causative bacteria were methicillin-resistant followed by gram-negative rods. Independent risk factors for SSI in pediatric patients undergoing spinal deformity surgery were scoliosis etiology, ASA class 3, and administration of antibiotic therapy twice daily.Level of Evidence: 3.

MIS-TLIF versus O-TLIF for single-level degenerative stenosis: study protocol for randomised controlled trial

INTRODUCTION

Patients with symptomatic single-level combination of degenerative stenosis and low-grade spondylolisthesis are often treated by nerve root decompression and spinal fusion. The gold standard is traditional open decompression and fusion, but minimally invasive method is more and more prevailing. However, there is lack of high-quality studies comparing these two techniques in order to obtain the advantages and certain indications to use one of these methods. The current study includes clinical, safety and radiological endpoints to determine the effectiveness of minimally invasive decompression and fusion (MIS-TLIF) over the traditional open one (O-TLIF).

METHODS AND ANALYSIS

All patients aged 40-75 years with neurogenic claudication or bilateral radiculopathy caused by single-level combination of degenerative stenosis and low-grade spondylolisthesis, confirmed by MRI with these symptoms persisting for at least 3 months prior to surgery, are eligible. Patients will be randomised into MIS-TLIF or traditional O-TLIF. The primary outcome measure is Oswestry Disability Index at 3-month follow-up term. The secondary outcomes are patient-reported outcome measures by the number of clinical scales, radiological parameters including sagittal balance parameters, safety endpoints and cost-effectiveness of each method. All patients will be analysed preoperatively, as well as on the 14th day of hospital stay (or on the day of hospital discharge), 3 months, 6 months, 12 months and 24 months postoperatively. The study has the design of a parallel group to demonstrate the non-inferior clinical results of MIS-TLIF compared with the traditional O-TLIF.

ETHICS AND DISSEMINATION

The study will be performed according to Helsinki Declaration. The study protocol was approved by the Local Ethical Committee of Priorov National Medical Research Center of Traumatology and Orthopedics in August 2020. Preliminary and final results will be presented in peer-reviewed journals, especially orthopaedic and spine surgery journals, at national and international congresses.

TRIAL REGISTRATION NUMBER

NCT04594980.

Development of Deployable Predictive Models for Minimal Clinically Important Difference Achievement Across the Commonly Used Health-related Quality of Life Instruments in Adult Spinal Deformity Surgery

STUDY DESIGN

Retrospective analysis of prospectively-collected, multicenter adult spinal deformity (ASD) databases.

OBJECTIVE

To predict the likelihood of reaching minimum clinically important differences in patient-reported outcomes after ASD surgery.

SUMMARY OF BACKGROUND DATA

ASD surgeries are costly procedures that do not always provide the desired benefit. In some series only 50% of patients achieve minimum clinically important differences in patient-reported outcomes (PROs). Predictive modeling may be useful in shared-decision making and surgical planning processes. The goal of this study was to model the probability of achieving minimum clinically important differences change in PROs at 1 and 2 years after surgery.

METHODS

Two prospective observational ASD cohorts were queried. Patients with Scoliosis Research Society-22, Oswestry Disability Index , and Short Form-36 data at preoperative baseline and at 1 and 2 years after surgery were included. Seventy-five variables were used in the training of the models including demographics, baseline PROs, and modifiable surgical parameters. Eight predictive algorithms were trained at four-time horizons: preoperative or postoperative baseline to 1 year and preoperative or postoperative baseline to 2 years. External validation was accomplished via an 80%/20% random split. Five-fold cross validation within the training sample was performed. Precision was measured as the mean average error (MAE) and R values.

RESULTS

Five hundred seventy patients were included in the analysis. Models with the lowest MAE were selected; R values ranged from 20% to 45% and MAE ranged from 8% to 15% depending upon the predicted outcome. Patients with worse preoperative baseline PROs achieved the greatest mean improvements. Surgeon and site were not important components of the models, explaining little variance in the predicted 1- and 2-year PROs.

CONCLUSION

We present an accurate and consistent way of predicting the probability for achieving clinically relevant improvement after ASD surgery in the largest-to-date prospective operative multicenter cohort with 2-year follow-up. This study has significant clinical implications for shared decision making, surgical planning, and postoperative counseling.

LEVEL OF EVIDENCE

4.

Effect of body mass index on patient outcomes of surgical intervention for the lumbar spine

BACKGROUND

Conflicting findings exist on the effect of obesity on outcomes of lumbar spine surgery; results depend on the diagnosis studied, procedure evaluated, definition of obesity, and specific outcomes measured. The purpose of this retrospective cohort study is to examine the effect of increasing body mass index (BMI) on surgical-related, health-related, and long-term outcomes of lumbar spine surgery in a single representative patient sample.

METHODS

Using a surgical registry from an integrated health care system, 8,049 instrumented lumbar spine cases were identified between 1/1/2009 and 09/30/2013. The sample was stratified into five BMI categories. Outcomes of interest included: (I) surgical-related factors and complications; (II) health-related complications; and (III) long-term complications. Mixed linear models, conditional logistic regressions, and survival analysis using a Cox regression model were conducted controlling for surgeon effects. Age, gender, diabetes status, smoking status, admitting diagnosis, and surgical approach were included as covariates.

RESULTS

Every 5 kg/m2 increase in BMI was associated with a significant increase in surgical time (7.8 minutes), estimated blood loss (EBL) (36.5 mL), risk of deep infection (OR =1.7 times), and deep vein thrombosis (DVT) (OR =1.5). BMI was not associated with increased incidence of other intraoperative or health-related complications. Rate of re-operation was 1.1 times higher with every 5 kg/m2 increase in BMI, but rate of re-operation due to adjacent segment disease (ASD) was not associated with BMI.

CONCLUSIONS

Obesity had an adverse effect on certain surgical-related, health-related and long-term surgical outcomes. The magnitude of this effect increased with increasing levels of obesity, which increases the medical burden associated with obesity.

Clinical Experiences of Non-fusion Dynamic Stabilization Surgery for Adjacent Segmental Pathology after Lumbar Fusion

BACKGROUND

As an alternative to spinal fusion, non-fusion dynamic stabilization surgery has been developed, showing good clinical outcomes. In the present study, we introduce our surgical series, which involves non-fusion dynamic stabilization surgery for adjacent segment pathology (ASP) after lumbar fusion surgery.

METHODS

Fifteen patients (13 female and 2 male, mean age of 62.1 years) who underwent dynamic stabilization surgery for symptomatic ASP were included and medical records, magnetic resonance images (MRI), and plain radiographs were retrospectively evaluated.

RESULTS

Twelve of the 15 patients had the fusion segment at L4-5, and the most common segment affected by ASP was L3-4. The time interval between prior fusion and later non-fusion surgery was mean 67.0 months. The Visual Analog Scale and Oswestry Disability Index showed values of 7.4 and 58.5% before the non-fusion surgery and these values respectively declined to 4.2 and 41.3% postoperatively at 36 months (p=0.027 and p=0.018, respectively). During the mean 44.8 months of follow-up, medication of analgesics was also significantly reduced. The MRI grade for disc and central stenosis identified significant degeneration at L3-4, and similar disc degeneration from lateral radiographs was determined at L3-4 between before the prior fusion surgery and the later non-fusion surgery. After the non-fusion surgery, the L3-4 segment and the proximal segment of L2-3 were preserved in the disc, stenosis and facet joint whereas L1-2 showed disc degeneration on the last MRI (p=0.032). Five instances of radiologic ASP were identified, showing characteristic disc-space narrowing at the proximal segments of L1-2 and L2-3. However, no patient underwent additional surgery for ASP after non-fusion dynamic stabilization surgery.

CONCLUSION

The proposed non-fusion dynamic stabilization system could be an effective surgical treatment for elderly patients with symptomatic ASP after lumbar fusion.