Are facet joint parameters risk factors for recurrent lumbar disc herniation? A pilot study in a Chinese population

Development and validation of a nomogram to predict the risk of residual low back pain after tubular microdiskectomy of lumbar disk herniation

OBJECTIVE

Tubular microdiskectomy (tMD) is one of the most commonly used for treating lumbar disk herniation. However, there still patients still complain of persistent postoperative residual low back pain (rLBP) postoperatively. This study attempts to develop a nomogram to predict the risk of rLBP after tMD.

METHODS

The patients were divided into non-rLBP (LBP VAS score < 2) and rLBP (LBP VAS score ≥ 2) group. The correlation between rLBP and these factors were analyzed by multivariate logistic analysis. Then, a nomogram prediction model of rLBP was developed based on the risk factors screened by multivariate analysis. The samples in the model are randomly divided into training and validation sets in a 7:3 ratio. The Receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the diskrimination, calibration and clinical value of the model, respectively.

RESULTS

A total of 14.3% (47/329) of patients have persistent rLBP. The multivariate analysis suggests that higher preoperative LBP visual analog scale (VAS) score, lower facet orientation (FO), grade 2-3 facet joint degeneration (FJD) and moderate-severe multifidus fat atrophy (MFA) are risk factors for postoperative rLBP. In the training and validation sets, the ROC curves, calibration curves, and DCAs suggested the good diskrimination, predictive accuracy between the predicted probability and actual probability, and clinical value of the model, respectively.

CONCLUSION

This nomogram including preoperative LBP VAS score, FO, FJD and MFA can serve a promising prediction model, which will provide a reference for clinicians to predict the rLBP after tMD.

Lumbar disc herniation: Prevention and treatment of recurrence: WFNS spine committee recommendations

Objective

This review aims to formulate the most current evidence-based recommendations on the epidemiology, prevention, and treatment of recurrent lumbar disc herniation (LDH).

Methods

We performed a systematic literature search in PubMed, Medline, and Google Scholar databases from 2012 to 2022 using the keywords "lumbar disc recurrence." Screening criteria resulted in 57 papers, which were summarized and presented at two international consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine Committee. The 57 papers covered the following topics: (1) Definition and incidence of recurrence after lumbar disc surgery; (2) Prediction of recurrence before primary surgery; (3) Prevention of recurrence by surgical measures; (4) Prevention of recurrence by postoperative measures; (5) Treatment options for recurrent disc herniation; (6) The outcomes of recurrent disc herniation surgery. We utilized the Delphi method and voted on eight final consensus statements.

Results and conclusion

Recurrence after disc herniation surgery may be considered a surgical complication, its incidence is approximately 5% and is different from overall re-operation incidence. There are multiple risk factors predicting LDH recurrence, including smoking, younger age, male gender, obesity, diabetes, disc degeneration, and presence of lumbosacral transitional vertebrae. The level of lumbar discectomy surgery and the amount of disc material removed do not correlate with recurrence rate. Minimally invasive discectomies may have higher recurrence rates, especially during the surgeon's learning period. However, the experience of the surgeon is not related to recurrence. High-quality studies are needed to determine if activity restriction, weight loss, smoking cessation, and muscle-strengthening exercises after primary surgery can help prevent recurrence of LDH.The best treatment option for recurrent disc herniation is still being discussed. While complications of minimally invasive techniques may be lower than open discectomy, outcomes are similar. Fusion should only be considered when spinal instability and/or spinal deformity are present. Clinical outcomes and patient satisfaction after recurrent disc herniation surgery are inferior to those after initial discectomy.

Analyzing isolated degeneration of lumbar facet joints: implications for degenerative instability and lumbar biomechanics using finite element analysis

The facet joint contributes to lumbar spine stability as it supports the weight of body along with the intervertebral discs. However, most studies on the causes of degenerative lumbar diseases focus on the intervertebral discs and often overlook the facet joints. This study aimed to investigate the impact of facet joint degeneration on the degenerative changes and diseases of the lumbar spine. A finite element model of the lumbar spine (L1-S1) was fabricated and validated to study the biomechanical characteristics of the facet joints. To simulate degeneration of the facet joint, the model was divided into four grades based on the number of degenerative segments (L4-L5 or L4-S1) and the contact condition between the facet joint surfaces. Finite element analysis was performed on four spine motions: flexion, extension, lateral bending, and axial torsion, by applying a pure moment to the upper surface of L1. Important parameters that could be used to confirm the effect of facet joint degeneration on the lumbar spine were calculated, including the range of motion (ROM) of the lumbar segments, maximum von Mises stress on the intervertebral discs, and reaction force at the facet joint. Facet joint degeneration affected the biomechanical characteristics of the lumbar spine depending on the movements of the spine. When analyzed by dividing it into degenerative onset and onset-adjacent segments, lumbar ROM and the maximum von Mises stress of the intervertebral discs decreased as the degree of degeneration increased in the degenerative onset segments. The reaction force at the facet joint decreased with flexion and increased with lateral bending and axial torsion. In contrast, lumbar ROM of the onset-adjacent segments remained almost unchanged despite severe degeneration of the facet joint, and the maximum von Mises stress of the intervertebral discs increased with flexion and extension but decreased with lateral bending and axial torsion. Additionally, the facet joint reaction force increased with extension, lateral bending, and axial rotation. This analysis, which combined the ROM of the lumbar segment, maximum von Mises stress on the intervertebral disc, and facet joint reaction force, confirmed the biomechanical changes in the lumbar spine due to the degeneration of isolated facet joints under the load of spinal motion. In the degenerative onset segment, spinal instability decreased, whereas in the onset-adjacent segment, a greater load was applied than in the intact state. When conducting biomechanical studies on the lumbar spine, considering facet joint degeneration is important since it can lead to degenerative spinal diseases, including adjacent segment diseases.

Machine Learning Predicts Recurrent Lumbar Disc Herniation Following Percutaneous Endoscopic Lumbar Discectomy

STUDY DESIGN

Retrospective study.

OBJECTIVES

To develop machine learning (ML) models to predict recurrent lumbar disc herniation (rLDH) following percutaneous endoscopic lumbar discectomy (PELD).

METHODS

We retrospectively analyzed 1159 patients who had undergone single-level PELD for lumbar disc herniation (LDH) between July 2014 to December 2019 at our institution. Various preoperative imaging variables and demographic metrics were brought in analysis. Student's t test and Chi-squared test were applied for univariate analysis, which were feature selection for ML models. We established ML models to predict rLDH: Artificial neural networks (ANN), Extreme Gradient Boost classifier (XGBoost), KNeighborsClassifier (KNN), Decision tree classifier (Decision Tree), Random forest classifier (Random Forest), and support vector classifier (SVC).

RESULTS

A total 130 patients (11.22%) were diagnosed as rLDH in 1159 patients. Recurrence occurred within 10.25 ± 11.05 months. Body mass index (BMI) (P = .027), facet orientation (FO) (P < .001), herniation type (P = .012), Modic changes (P = .004), and disc calcification (P = .013) are significant factors in univariate analysis (P < .05). Extreme Gradient Boost classifier, Random Forest, ANN showed fine area under the curve, .9315, .9220, and .8814 respectively.

CONCLUSION

We developed a deep learning and 2 ensemble models with fine performance in prediction of rLDH following PELD. Predicting re-herniation before surgery has the potential to optimize decision-making and meaningfully decrease the rates of rLDH following PELD. Our ML model identified higher BMI, lower FO, Modic changes, disc calcification in a non-protrusive region, and herniation type (noncontained herniation) as significant features for predicting rLDH.

Estimating surgical probability: Development and validation of a prognostic model for patients with lumbar disc herniation treated with acupuncture

Lumbar disc herniation (LDH) is a common cause of pain in the lumbar spine and legs. While acupuncture has become the primary conservative treatment for LDH, some patients experience treatment failure and require surgery, causing substantial concern for clinicians. We developed an effective personalized clinical prediction model to identify the independent risk factors associated with acupuncture failure in patients with LDH. Our model aimed to predict the probability of surgery within 6 months of acupuncture failure in patients with LDH. A total of 738 patients with LDH who underwent acupuncture at 4 Chinese hospitals between January 2019 and October 2021 were selected. The patients were divided into training (n = 496) and validation (n = 242) cohorts. Seven predictive variables, including smoking, Oswestry Disability Index (ODI) score, lower-limb herniation, disc herniation type, lumbar spinal stenosis, lumbar lateral recess stenosis, and acupuncture frequency, were selected as risk factors using least absolute shrinkage and selection operato (LASSO) regression. A prediction model was developed using multivariate logistic regression analysis and a nomogram was constructed. The model exhibited good discrimination, with an area under the ROC curve (AUC) of 0.903 for the development cohort and 0.899 for the validation cohort. The Hosmer-Lemeshow goodness-of-fit test was a good fit for both cohorts (P = .956 for the development cohort; P = .513 for the validation cohort). Decision curve analysis (DCA) demonstrated that the threshold probabilities for the 2 cohorts ranged from > 4% and 5-95%, respectively. Therefore, the prediction model had a good net benefit. The nomogram established in this study, incorporating 7 risk factors, demonstrated a good predictive ability. It could predict acupuncture failure in LDH patients and the risk of surgery within 6 months, enabling physicians to conduct individualized treatment measures.

Moderate to Severe Multifidus Fatty Atrophy is the Risk Factor for Recurrence After Microdiscectomy of Lumbar Disc Herniation

OBJECTIVE

We attempted to investigate the potential risk factors of recurrent lumbar disc herniation (rLDH) after tubular microdiscectomy.

METHODS

We retrospectively analyzed the data of patients who underwent tubular microdiscectomy. The clinical and radiological factors were compared between the patients with and without rLDH.

RESULTS

This study included 350 patients with lumbar disc herniation (LDH) who underwent tubular microdiscectomy. The overall recurrence rate was 5.7% (20 of 350). The visual analogue scale (VAS) score and Oswestry Disability Index (ODI) at the final follow-up significantly improved compared with those preoperatively. There was no significant difference in the preoperative VAS score and ODI between the rLDH and non-rLDH groups, while the leg pain VAS score and ODI of the rLDH group were significantly higher than those of the non-rLDH group at final follow-up. This suggested that rLDH patients had a worse prognosis than non-rLDH patients even after reoperation. There were no significant differences in sex, age, body mass index, diabetes, current smoking and drinking, disc height index, sagittal range of motion, facet orientation, facet tropism, Pfirrmann grade, Modic changes, interdisc kyphosis, and large LDH between the 2 groups. Univariate logistic regression analysis revealed that rLDH was associated with hypertension, multilevel microdiscectomy, and moderate-severe multifidus fatty atrophy (MFA). A multivariate logistic regression analysis indicated that MFA was the sole and strongest risk factor for rLDH after tubular microdiscectomy.

CONCLUSION

Moderate-severe MFA was a risk factor for rLDH after tubular microdiscectomy, which can serve as an important reference for surgeons in formulating surgical strategies and the assessment of prognosis.

Risk Factors for Recurrence After Percutaneous Endoscopic Lumbar Discectomy: A Meta-Analysis

OBJECTIVE

Postoperative recurrence of percutaneous endoscopic lumbar disc increases the physical damage and financial burden on patients and negatively affects physicians' treatment decisions. We conducted this meta-analysis to explore the risk factors for postoperative recurrence of percutaneous endoscopic lumbar disc for lumbar disc herniation.

METHODS

We conducted article search in the PubMed, EMBASE and Cochrane Library databases. PRISMA guidelines were followed in this review. The data are statistically analyzed by the Roundup Manager (version 3.6.1). The results of the meta-analysis are presented in the form of forest-like plots.

RESULTS

We included 13 articles and identified 7524 cases. Patients with older age (odds ratio [OR] = 1.28, 95% confidence interval [CI]: 1.18-1.40), higher body mass index (OR = 1.16, 95% CI: 1.05-1.28), smoker (OR = 1.73, 95% CI: 0.95-3.15), degenerative grades ≥3 (OR = 6.07, 95% CI: 2.81-13.11), and postoperative sagittal motion ≥10° (OR = 2.42, 95% CI: 1.63-3.58) have a higher recurrence rate.

CONCLUSIONS

A thorough preoperative evaluation is essential to prevent postoperative recurrence of percutaneous endoscopic lumbar discectomy. The study addresses several factors of preoperative evaluation, which is hopeful to provide a reference for neurosurgeons.

Are there correlations between facet joint parameters and lumbar disk herniation laterality in young adults?

OBJECTIVE

We aimed to determine whether there is an association, in young adults, between the occurrence of lumbar disk herniation (LDH) at a given segment and the segment's facet joint parameters [facet orientation (FO) and tropism (FT)]. In addition, associations between facet joint parameters in the corresponding segment and LDH laterality were also investigated.

METHODS

We retrospectively analyzed data from 529 patients who were between 18 and 35 years old, who had experienced single-level LDH (L4-5 or L5-S1) between June 2017 and December 2019, and with<2 years of clinical history. We included an additional 122 patients with no history of LDH as an age-matched control group. LDH were classified by laterality (left-sided, right-sided, or central herniation). At each level, we investigated the relationship between facet joint parameters and herniation laterality.

RESULTS

FO_A values at the L4-L5 level and the L5-S1 level were significantly lower and FT was higher for the LDH group compared with those for the control group. The level at which LDH occurred, FO_L, FO_R, and FT differed significantly among the three groups. There was a significant association between herniationlaterality and FO at the L4-L5 level but not at the L5-S1 level.

CONCLUSIONS

Abnormal facet joint parameters are significantly associated with LDH. Young adults with higher FT should be paid more attention, to prevent the occurrence of LDH. Compared with L5-S1 level, intervertebral disk herniation at the L4-L5 level tended to occur ipsilateral to the side with a lower facet joint angle when FT was present.

The biomechanical influence of facet joint parameters on corresponding segment in the lumbar spine: a new visualization method

BACKGROUND CONTEXT

Facet joints have been discussed as influential factors in the development of lumbar degeneration, which includes disc herniation and degenerative lumbar spondylolisthesis. Facet orientation (FO) and facet tropism (FT) are two important structural parameters of the lumbar facet joints. Many previous studies have focused on single parameter analysis of the lumbar spine. Owing to the correlation between independent variables, single-factor analysis cannot reflect the interaction between variables; however, there has been no corresponding biomechanical method developed to address this problem.

PURPOSE

To investigate the complex biomechanical influences on the lumbar spine when vertebral FO and FT are varied using finite element analysis (FEA) and contour maps visualization, and analyze the biomechanical role of facet joint structural parameters in the process of lumbar degenerative diseases.

STUDY DESIGN

A biomechanical modelling, analysis, and verification study was performed.

METHODS

A three-dimensional non-linear FEA model of 3 denucleated intervertebral discs (L2-3, L3-4, L4-5) with adjacent vertebral bodies (L2-L5) was created. Previously performed in vitro experiments provided experimental data for the range of motion in each load direction that was used for calibration. For 12 lumbar models, different facet joint angles relative to the sagittal plane at both L3-4 facet joints were simulated for 35°≤FO≤50° and 0°≤FT≤15°. By modifying different values of FO and FT, FEA simulation of different lumbar spine models was performed. Contour maps were used to visualize the FO- and FT-relevant data.

RESULTS

Under flexion, extension, and torsion moments, facet joint contact force and intradiscal stress increased with increasing FT. In the condition where FT remained 0° and increasing FO values, facet joint contact force and intradiscal stress remained low with no apparent increasing or decreasing trend when the model was under flexion, extension, and torsion moments. In the condition where FO and the FT values were varied at the same time, the highest force and stress regions in the contour maps were observed when all three types of moments were applied. Stress distributions of the L3-4 disc with different FT and FO values showed disc stress increased significantly with increases of FT and was concentrated on the ipsilateral region of the facet joint with the more sagittal orientation.

CONCLUSIONS

The combination of FO and FT has an important impact on the corresponding disc and facet joints, but FT played a more significant role. Moreover, disc stress was concentrated on the ipsilateral region of facet joint with greater sagittal orientation when FT existed. FT with high sagittal orientation may increase risk of recurrent LDH due to increase ipsilateral disc pressure.

CLINICAL SIGNIFICANCE

These biomechanical findings may help clinicians to understand the prognosis of some lumbar degenerative conditions.