Analysis of risk factors and postoperative predictors for recurrent lumbar disc herniation

Biomechanical changes in lumbar intervertebral discs after percutaneous endoscopic transforaminal discectomy surgery at different Body Mass Index (BMI) categories

OBJECTIVE

Percutaneous Endoscopic Transforaminal Discectomy (PETD) is recognized as the leading surgical intervention for lumbar disc herniation (LDH). Moreover, Body Mass Index (BMI) has been established as an independent risk factor for disc reherniation post-PETD. Furthermore, there is a lack of studies investigating the biomechanical changes in the disc post-PETD in relation to diverse BMI levels.

METHODS

A three-dimensional nonlinear finite element model was developed to simulate the L3-S1 lumbar spine, and a surgical model of the lumbar 4/5 right PETD was also constructed. Forces of 392 N (BMI 20.76 kg/m2), 457 N (24.22 kg/m2), 523 N (27.68 kg/m2), 588 N (31.14 kg/m2) and 653 N (34.6 kg/m2) were applied from the superior edge of the L3 vertebrae. The equivalent von Mises stresses and maximum deformation of the L4/5 nucleus pulposus were observed in normal group and PETD surgery group.

RESULTS

We established normal and PETD surgery model with different BMIs, contributes to understand the equivalent von Mises stresses and maximum deformation of the L4/5 nucleus pulposus with different BMI. The results indicated that the rise in BMI correlates with heightened equivalent von Mises stresses and maximum deformation within the L4/5 nucleus pulposus in both in normal group and PETD surgery group. Besides, the von Mises stress and maximum deformation of the NP in flexion loading are significantly higher than in other loading conditions under the same BMI condition. These values, alongside the occurrence of high-stress areas, display fluctuations across distinct postures, under the influence of BMI. Furthermore, a discernible accumulation of stress was noted within the compromised regions of the nucleus pulposus.

CONCLUSION

The study suggested that patients who undergone PETD surgery should refrain from engaging in strenuous activities especially flexion during early rehabilitation through finite element analysis. For patients with a high BMI, it is advisable to scientifically reduce weight before and after the surgery in order to maintain appropriate stress on the intervertebral disc.

How to spot the recurring lumbar disc? Risk factors for recurrent lumbar disc herniation (rLDH) in adult patients with lumbar disc prolapse: a systematic review and meta-analysis

Despite a fast-growing evidence-base examining the relationship of certain clinical and radiological factors such as smoking, BMI and herniation-type with rLDH, there remains much debate around which factors are clinically important. We conducted a systematic review and meta-analysis to identify risk factors for recurrent lumbar disc herniation (rLDH) in adults after primary discectomy. A systematic literature search was carried out using Ovid-Medline, EMBASE, Cochrane library and Web of Science databases from inception to 23rd June-2022. Observational studies of adult patients with radiologically-confirmed rLDH after ≥3 months of the initial surgery were included, and their quality assessed using the Quality-In-Prognostic-Studies (QUIPS) appraisal tool. Meta-analyses of univariate and multivariate data and a sensitivity-analysis for rLDH post-microdiscectomy were performed. Twelve studies (n=4497, mean age:47.3; 34.5% female) were included, and 11 studies (n=4235) meta-analysed. The mean follow-up was 38.4 months. Mean recurrence rate was 13.1% and mean time-to-recurrence was 24.1 months (range: 6-90 months). Clinically, older age (OR:1.04, 95%CI:1.00-1.08, n=1014), diabetes mellitus (OR:3.82, 95%CI:1.58-9.26, n=2330) and smoking (OR:1.80, 95%CI:1.03- 3.14, n=3425) increased likelihood of recurrence. Radiologically, Modic-change type-2 (OR:7.93, 95%CI:5.70-11.05, n=1706) and disc extrusion (OR:12.23, 95%CI:8.60-17.38, n=1706) increased likelihood of recurrence. The evidence did not support an association between rLDH and sex; BMI; occupational labour/driving; alcohol-consumption; Pfirmann- grade, or herniation-level. Older patients, smokers, patients with diabetes, those with type-2 Modic-changes or disc extrusion are more likely to experience rLDH. Higher quality studies with robust adjustment of confounders are required to determine the clinical bearing of all other potential risk factors for rLDH.

Effect of Obesity on Surgical Outcomes of Lumbar Microdiscectomy: A Retrospective Analysis of 525 Patients

INTRODUCTION

Obesity has been implicated in higher rates of intra-operative complications, as well as increased risk for recurrent herniation and re-operation following lumbar microdiscectomy (LMD). However, the current literature is still controversial about whether obesity adversely affects surgical outcomes, especially a higher re-operation rate. In this study, we have compared surgical outcomes such as recurrence of symptoms, recurrence of disc herniation, and re-operation rates in obese and non-obese patients undergoing one segment LMD.

METHODS

A retrospective review was conducted on patients undergoing single-level LMD between 2010-2020 at an academic institution. Exclusion criteria included prior lumbar surgery. Outcomes assessed included the presence of persistent radicular pain, imaging evidence of recurrent herniation, and the need for re-operation due to recurrent herniation.

RESULTS

A total of 525 patients were included in the study. The mean±SD body mass index (BMI) was 31.2±6.6 (range 16.2-70.0). The mean follow-up was 273.8±445.2 days (range 14-2494). Reherniation occurred in 84 patients (16.0%), and 69 (13.1%) underwent re-operation due to persistent recurrent symptoms. Neither reherniation nor re-operation was significantly associated with BMI (p = 0.47 and 0.95, respectively). Probit analysis did not show any significant association between BMI and the need for re-operation following LMD.

CONCLUSION

Obese and non-obese patients experienced similar surgical outcomes. Our results showed that BMI did not adversely affect reherniation or re-operation rate following LMD. If clinically indicated, LMD can be performed in obese patients with disc herniation without a significantly higher re-operation rate.

A 9-year retrospective cohort of patients with lumbar disc herniation: Comparison of patient characteristics and recurrence frequency by smoking status

To evaluate the association between smoking status and patient characteristics and to identify risk factors associated with recurrence in patients who underwent surgery for lumbar disc herniation (LDH). This retrospective study was carried out at Lokman Hekim University, Ankara, Turkey between January 1, 2021 and January 1, 2022. The medical data of patients who underwent microsurgical discectomy for LDH were retrospectively recorded. Patients with any reemergence of LDH within a 6-month period after surgery were defined as having recurrent LDH. A total of 1109 patients were included in the study and mean age was 50.7 ± 14.3 years. The frequency of hernia at L2-L3 and L3-L4 levels was higher in the nonsmoker group (P < .001). The frequency of cases with Pfirrmann Grade 4 degeneration was higher in the nonsmoker group than in smokers and ex-smokers (P < .001). Protrusion-type hernias were more common in nonsmokers (P = .014), whereas paracentral hernias were more common in smokers (P < .001). The overall frequency of recurrence was 20.4%, and was higher in smokers than in non-smokers and ex-smokers (P < .001). Multivariable logistic regression revealed that current smoking (OR: 2.778, 95% CI [confidence interval]: 1.939-3.980, P < .001), presence of Pfirrmann Grade 4&5 disc degeneration (OR: 4.217, 95% CI: 2.966-5.996, P < .001), and paracentral herniation (OR: 5.040, 95% CI: 2.266-11,207, P < .001) were associated with higher risk of recurrence, whereas presence of sequestrated disc was associated with lower risk of recurrence (OR: 2.262, 95% CI:0.272-0.717, P = .001). Taken together, our data show that smoking, increased degree of degeneration and paracentral hernia increase the risk of LDH recurrence, while sequestrated disc appears to decrease risk. Taking steps to combat smoking in individuals followed for LDH may reduce the risk of recurrence in LDH patients.

Feasibility and Assessment of a Machine Learning-Based Predictive Model of Outcome After Lumbar Decompression Surgery

STUDY DESIGN

Retrospective study at a unique center.

OBJECTIVE

The aim of this study is twofold, to develop a virtual patients model for lumbar decompression surgery and to evaluate the precision of an artificial neural network (ANN) model designed to accurately predict the clinical outcomes of lumbar decompression surgery.

METHODS

We performed a retrospective study of complete Electronic Health Records (EHR) to identify potential unfavorable criteria for spine surgery (predictors). A cohort of synthetics EHR was created to classify patients by surgical success (green zone) or partial failure (orange zone) using an Artificial Neural Network which screens all the available predictors.

RESULTS

In the actual cohort, we included 60 patients, with complete EHR allowing efficient analysis, 26 patients were in the orange zone (43.4%) and 34 were in the green zone (56.6%). The average positive criteria amount for actual patients was 8.62 for the green zone (SD+/- 3.09) and 10.92 for the orange zone (SD 3.38). The classifier (a neural network) was trained using 10,000 virtual patients and 2000 virtual patients were used for test purposes. The 12,000 virtual patients were generated from the 60 EHR, of which half were in the green zone and half in the orange zone. The model showed an accuracy of 72% and a ROC score of 0.78. The sensitivity was 0.885 and the specificity 0.59.

CONCLUSION

Our method can be used to predict a favorable patient to have lumbar decompression surgery. However, there is still a need to further develop its ability to analyze patients in the "failure of treatment" zone to offer precise management of patient health before spinal surgery.

Return to Work Guidelines Following Neurosurgical Procedures

Recovery time following surgical procedures is a consideration every practicing surgeon must deliberate upon throughout his or her career. The decision to restrict patients from returning to work or various activities encountered on a daily basis following an operation is dependent on many factors. Surgeons must take into account patient population, individual comorbid conditions, complexity and length of surgery, immediate postoperative course, and baseline functional abilities. Thus, returning to work and various activities, including physical activity, work-related activity, and recreational activity alike, following invasive procedures is individualized from patient to patient. Most spinal procedures are performed by neurosurgeons or orthopedic surgeons. This article suggests a framework to guide appropriate return to work and activity escalation time frames following various spinal procedures. 

The relationship between preoperative predictive factors for clinical outcome in patients operated for lumbar spinal stenosis by decompressive laminectomy

Background:

Our hypothesis was that by identifying certain preoperative predictive factors, we could favorably impact clinical outcomes in patients undergoing decompressive surgery for lumbar spinal stenosis (LSS).

Methods:

In this retrospective study, there were 65 patients (2016–2018) with symptomatic LSS who underwent decompressive laminectomy without fusion. Their clinical outcomes were assessed utilizing the Oswestry Disability Index (ODI). Multiple preoperative variables were studied to determine which ones would help predict improved outcomes: gender, age, body mass index (BMI), general/neurological examination, smoking, and drug therapies (anxiolytics and/or antidepressants).

Results:

All patients demonstrated statistically significant improvement on the ODI. Multivariate analysis revealed that those with higher preoperative BMI had significantly lower ODI on 1-year follow-up examinations, reflecting poorer outcomes. Postoperatively, 44 patients (67%) exhibited lower utilization of anxiolytic medications, 52 patients (80%) showed reduced use of antidepressant drugs, and pain medications utilization was reduced in 33 patients (50%).

Conclusion:

Decompressive laminectomy without fusion effectively managed LSS. It reduced patients’ use of pain, anxiety, and antidepressant medications. In addition, we found that increased preoperative BMIs contributed to poorer postoperative outcomes (e.g., ODI values).