Recurrent disc herniation following percutaneous endoscopic lumbar discectomy preferentially occurs when Modic changes are present

New-Occurrence of Postoperative Modic Changes and Its Influence on the Surgical Prognosis After Percutaneous Endoscopic Lumbar Disc Discectomy

OBJECTIVES

Lumbar disc herniation (LDH) is a common degenerative spinal disease in clinical practice. This study aims to investigate the impact of Modic changes (MCs) on postoperative recovery and disease recurrence following percutaneous endoscopic lumbar disc discectomy (PELD), providing important insights for improving the management of chronic low back pain. This study investigates the 1-year progression rate of MCs after PELD and their impact on surgical outcomes and recurrence.

METHODS

This retrospective cohort study analyzed data from 419 patients with single-segment lumbar disc herniation who underwent PELD between January 2019 and December 2022. Lumbar MRI assessed preoperative and postoperative MCs. Pain levels and surgical outcomes were evaluated using the visual analog scale, Oswestry Disability Index, and Macnab criteria. Univariate analysis explored the relationship between postoperative MCs and pain, while subgroups investigated the associations between postoperative efficacy, recurrence, and MCs type and area.

RESULTS

One-year follow-up revealed that the probability of MCs postsurgery was 24.8%. Patients with postoperative MCs had significantly lower pain scores compared with the control group (p < 0.05). Univariate analysis indicated that the type and area of postoperative MCs were risk factors for poor outcomes in PELD patients (p < 0.05). During the 1-year follow-up, recurrence rates in the no-MCs and MCs groups were 3.8% and 9.6%, respectively (p < 0.05). Univariate analysis concluded that the area of postoperative MCs was a risk factor for PELD recurrence.

CONCLUSION

The postoperative MCs, as a risk factor, may have a detrimental effect on the surgical efficacy and short-term recurrence of LDH following PELD based on a large sample. Furthermore, the harmful effect is affected by the area and type of the postoperative MCs.

Identification of copper death-associated molecular clusters and immunological profiles for lumbar disc herniation based on the machine learning

Lumbar disc herniation (LDH) is a common clinical spinal disorder, yet its etiology remains unclear. We aimed to explore the role of cuproptosis-related genes (CRGs) and identify potential diagnostic biomarkers. Our analysis involved interrogating the GSE124272 and GSE150408 datasets for differential gene expression profiles associated with CRGs and immune characteristics. Molecular clustering was performed on LDH samples, followed by expression and immune infiltration analyses. Using the WGCNA algorithm, specific genes within CRG clusters were identified. After selecting the most predictive genes from the optimal model, four machine learning models were constructed and validated. This study identified nine CRGs associated with copper-regulated cell death. Two copper-containing molecular clusters linked to death were detected in LDH samples. Elevated expression and immune infiltration levels were found in LDH patients, particularly in CRG cluster C2. Utilizing XGB, five genes were identified for constructing a diagnostic model, achieving an area under the curve values of 0.715. In conclusion, this research provides valuable insights into the association between LDH and copper-regulated cell death, alongside proposing a promising predictive model.

Optimizing prediction accuracy for early recurrent lumbar disc herniation with a directional mutation-guided SVM model

Percutaneous endoscopic lumbar discectomy (PELD) is one of the main means of minimally invasive spinal surgery, and is an effective means of treating lumbar disc herniation, but its early recurrence is still difficult to predict. With the development of machine learning technology, the auxiliary model based on the prediction of early recurrent lumbar disc herniation (rLDH) and the identification of causative risk factors have become urgent problems in current research. However, the screening ability of current models for key factors affecting the prediction of rLDH, as well as their predictive ability, needs to be improved. Therefore, this paper presents a classification model that utilizes wrapper feature selection, developed through the integration of an enhanced bat algorithm (BDGBA) and support vector machine (SVM). Among them, BDGBA increases the population diversity and improves the population quality by introducing directional mutation strategy and guidance-based strategy, which in turn allows the model to secure better subsets of features. Furthermore, SVM serves as the classifier for the wrapper feature selection method, with its classification prediction results acting as a fitness function for the feature subset. In the proposed prediction method, BDGBA is used as an optimizer for feature subset filtering and as an objective function for feature subset evaluation based on the classification results of the support vector machine, which improves the interpretability and prediction accuracy of the model. In order to verify the performance of the proposed method, this paper proves the performance of the model through global optimization experiments and prediction experiments on real data sets. The accuracy of the proposed rLDH prediction model is 93.49% and sensitivity is 88.33%. The experimental results show that Level of herniated disk, Modic change, Disk height, Disk length, and Disk width are the key factors for predicting rLDH, and the proposed method is an effective auxiliary diagnosis method.

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.

Comparison of Clinical and Radiographic Outcomes Between Transforaminal Endoscopic Lumbar Discectomy and Microdiscectomy: A Follow-up Exceeding 5 Years

OBJECTIVE

To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD).

METHODS

The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients' clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated.

RESULTS

During a mean follow-up of 5.5 years (range, 5-7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio.

CONCLUSION

Both TELD and MD provide generally satisfactory long-term clinical outcomes for patients with LDH. TELD can be used as a reliable alternative to MD with less surgical trauma. Modic type II changes, decreased preoperative intervertebral height, and a high body mass index are predictors of a poor prognosis.

Predicting and analysing of the unfavourable outcomes of early applicated percutaneous endoscopic interlaminar discectomy for lumbar disc herniation: development and validation based nomogram

OBJECTIVE

To predict and analyse the unfavourable outcomes of early applicated percutaneous endoscopic interlaminar discectomy for lumbar disc herniation.

METHODS

Information of 426 patients treated by early applicated percutaneous endoscopic interlaminar discectomy (PEID) for lumbar disc herniation (LDH) at our hospital from June 2017 to October 2021 in addition to 17 other features was collected. The risk factors were selected by the least absolute shrinkage and selection operator method (LASSO) regression. Then, a prediction model (nomogram) was established to predict the unfavourable outcomes of using the risk factors selected from LASSO regression. Bootstrap (n = 1000) was used to perform the internal validation, and the performance of the model was assessed by the concordance index (C-index), receiver operating characteristic curve, and calibration curve. The decision curve analysis (DCA) and clinical impact curve (CIC) were used to assess the clinical utility of the model, respectively.

RESULTS

Finally, 53 of 426 patients showed unfavourable outcomes. Five potential factors, Modic change, Calcification, Lumbar epidural steroid injection preoperative, Articular process hyperplasia and cohesion, and Laminoplasty technique, were selected according to the LASSO regression, that identified the predictors to establish nomogram model. Meanwhile, the C-index of the prediction nomogram was 0.847, the area under the receiver operating characteristic curve value was 0.847, and the interval bootstrapping (n = 1000) validation C-index was 0.809. The model has good practicability for clinics according to the DCA and CIC.

CONCLUSION

This nomogram model has good predictive performance and clinical practicability, which could provide a certain basis for predicting unfavourable outcomes of early applicated PEID for LDH.

Advancing insights into recurrent lumbar disc herniation: A comparative analysis of surgical approaches and a new classification

Background

The management of recurrent lumbar disc herniation (rLDH) lacks a consensus. Consequently, the choice between repeat microdiscectomy (MD) without fusion, discectomy with fusion, or endoscopic discectomy without fusion typically hinges on the surgeon's expertise. This study conducts a comparative analysis of postoperative outcomes among these three techniques and proposes a straightforward classification system for rLDH aimed at optimizing management.

Patients and Methods

We examined the patients treated for rLDH at our institution. Based on the presence of facet resection, Modic-2 changes, and segmental instability, they patients were categorized into three groups: Types I, II, and III rLDH managed by repeat MD without fusion, MD with transforaminal lumbar interbody fusion (TLIF) (MD + TLIF), and transforaminal endoscopic discectomy (TFED), respectively.

Results

A total of 127 patients were included: 52 underwent MD + TLIF, 50 underwent MD alone, and 25 underwent TFED. Recurrence rates were 20%, 12%, and 0% for MD alone, TFED, and MD + TLIF, respectively. A facetectomy exceeding 75% correlated with an 84.6% recurrence risk, while segmental instability correlated with a 100% recurrence rate. Modic-2 changes were identified in 86.7% and 100% of patients experiencing recurrence following MD and TFED, respectively. TFED exhibited the lowest risk of durotomy (4%), the shortest operative time (70.80 ± 16.5), the least blood loss (33.60 ± 8.1), and the most favorable Visual Analog Scale score, and Oswestry Disability Index quality of life assessment at 2 years. No statistically significant differences were observed in these parameters between MD alone and MD + TLIF. Based on this analysis, a novel classification system for recurrent disc herniation was proposed.

Conclusion

In young patients without segmental instability, prior facetectomy, and Modic-2 changes, TFED was available should take precedence over repeat MD alone. However, for patients with segmental instability, MD + TLIF is recommended. The suggested classification system has the potential to enhance patient selection and overall outcomes.

Novel Modic grading scoring system and its clinical validation: a preliminary investigation

PURPOSE

To propose a novel Modic grading scoring system and explore the relationship between the Modic grading score and disc degeneration, disc herniation, disc height, and clinical symptom scores.

METHOD

In total, 194 patients were included in the study. The new Modic grading scoring system included four indicators: invaded vertebral height, invaded endplate length, endplate morphology, and grade of endplate defects. The severity of Modic changes was visually quantified by numerical scores, and the kappa value was used to verify the interobserver and intraobserver reliability. Spearman correlation analysis was used to explore the relationship between the Modic grading score and intervertebral disc degeneration, disc herniation, disc height, and clinical symptom scores.

RESULTS

The interobserver and intraobserver reliability showed substantial to almost perfect agreement in the new Modic grading scoring system. The Modic grading score was positively correlated with intervertebral disc degeneration (r = 0.757, p < 0.001) and negatively correlated with the intervertebral disc height index (r = - 0.231, p < 0.001). There was no significant correlation between the Modic grading scoring system and disc herniation (r = 0.369, p = 0.249). Additionally, there was no significant correlation between the Modic grading score and the Japanese Orthopaedic Association score (r = - 0.349, p = 0.25), Oswestry Disability Index score (r = 0.246, p = 0.11), or visual analogue scale score (r = 0.315, p = 0.35).

CONCLUSION

The new Modic grading scoring system had good interobserver and intraobserver reliability. The Modic grading score was positively correlated with intervertebral disc degeneration and negatively correlated with the intervertebral disc height.

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.

Analysis of risk factors for post-operative recurrence after percutaneous endoscopic lumbar discectomy in patients with lumbar disc herniation: a meta-analysis

BACKGROUND

This study aimed to systematically evaluate risk factors for post-operative recurrence after percutaneous endoscopic lumbar discectomy (PELD) in patients with lumbar disc herniation (LDH).

METHODS

The eligible studies were retrieved from PubMed, Embase, and Web of Science databases. Quality assessment was performed. The effects of binary variables (sex, Modic change (MC), type 2 diabetes (T2DM), and smoking) on post-operative recurrence were evaluated as odds ratio (OR) and 95% confidence interval (CI). The effects of continuous variables (sagittal range of motion (SROM), body mass index (BMI), and age) were assessed as weighted mean difference (WMD) and 95% CI. Sensitivity analysis and publication bias were conducted to evaluate the reliability of pooled results.

RESULTS

Eight studies were included, and their methodological quality was medium. MC (OR (95% CI) = 3.88 (2.24-6.74), P < 0.001), smoking (OR (95% CI) = 1.87 (1.45, 2.42), P < 0.001), T2DM (OR (95% CI) = 1.61 (1.12, 2.31), P = 0.010), SROM (WMD (95% CI) = 2.33 (0.95, 3.70), P = 0.001), BMI (WMD (95% CI) = 1.68 (1.37, 1.99) kg/m2, P < 0.001), and age (WMD (95% CI) = 9.95 (5.05, 14.86) years, P < 0.001) were significantly related to post-operative recurrence in patients with LDH after PELD. Significant publication bias was not observed among studies in all outcome indicators.

CONCLUSION

Our findings reveal that high levels of age, BMI, and SROM, history of T2DM or smoking, or more MC may be correlated with post-operative recurrence after PELD.

Analogy of Lumbar Disc: Retained, Residual, or Recurrent Disc?

Discectomy is a standard surgery for disc herniation performed by senior, experienced as well as young trainee spine surgeons. Yet, they both have patients returning with radicular pain. Sometimes, it is attributed to insufficient decompression in the primary surgery, sometimes to re-herniation at the same level, and sometimes thought as new disc herniation at a different level. The primary surgery is often blamed for the recurrence of the pain, without an assessment of the clinical condition of the patient. Surgeons use the terms recurrent, residual, and retained disc interchangeably as per their convenience without understanding the actual disc pathology. This causes errors in further treatment and dissatisfaction in patients. In this short review, we intend to clear the baffling terminologies pertaining to discectomy and help the readers to identify the exact nodus of the patient’s plight. The optimal extent of disc excision for a satisfactory outcome is not strictly defined [1]. Two main types of discectomy are subtotal discectomy, in which the annulus is opened and all accessible disc material is removed by curettage of the endplate; and limited discectomy, in which only the loose fragments are removed [1]. Patients who undergo subtotal discectomy experience progressive degeneration and back pain at the operated level compared with patients who undergo limited discectomy, which may eventually require spinal fusion at that level [2, 3] The problem with limited discectomy, on the other hand, is the higher recurrence rate due to the remaining disc material herniating later [2]. The surgical method may also have a bearing on the results. Open discectomy is based on direct visualization of decompression of the nerve root, whereas newer techniques such as microscopic and percutaneous endoscopic discectomy use indirect methods to confirm the adequacy of decompression, such as checking the free mobility of the traversing nerve root, the free mobility of the probe in the epidural space, and the removal of loose fragments which were identified on pre-operative magnetic resonance imaging (MRI) [1]. Percutaneous endoscopic discectomy allows for smaller incisions, less soft-tissue trauma, and faster recovery, resulting in greater relief of back pain and allowing an earlier return to work [4]. However, studies have shown that up to 2.8–15% of patients treated with limited discectomy using percutaneous endoscopic disc removal had residual disc material on immediate post-operative MRI examination [5]. Therefore, these techniques are subjective and dependent on the surgeon’s experience and skill and may result in inadequate decompression. Post-operatively, these patients may not experience the expected pain relief and continue to have radicular symptoms. In some patients, pain may be relieved for a short period of time, after which the same symptoms may recur, either due to re-herniation at the same level or at adjacent levels. Hence, it is very important to know the types of inefficiencies in disc removal, namely recurrence, retained, residual, and relapsed disc. Distinguishing the causes of pain after surgery can help surgeons do better pre-operative planning and make better intraoperative decisions, thereby helping them to choose a clear endpoint for decompression. This can also help patients by preventing the need for reoperation and achieving better functional outcomes after surgery. Recurrent Disc A disc recurrence is defined as a re-herniation of disc material at the previously operated level with the recurrence of similar pain after a period of relief of minimum 6 months and MRI confirmation, which may occur on the same or contralateral side (Fig. 1) [6-9]. In up to 5–15% patients, disc herniation can recur [10]. However, if stricter definition of recurrence is used, with cases restricted to recurrence at the same level and side as previous operation, the recurrence rate was found to be 2–5%. [9, 10] Risk factors for recurrence of a lumbar disc prolapse include disc degeneration, modic changes in the endplate, trauma to back, advanced age, and smoking [11] Radiological features such as increased disc height, lumbosacral transitional vertebrae, and segmental instability may also predict recurrence [4, 12]. It has been suggested that contralateral nucleus pulposus herniation may occur if the annulus on the opposite side is damaged during primary discectomy and only limited fragments are removed. In the case of a recurrent disc herniation on the opposite side, removal of the opposite annulus and disc material may damage the posterior longitudinal ligament and affect lumbar biomechanics and spinal stability. The average time between primary surgery and recurrent disc herniation symptoms was reported to be 17 ± 21 months by Eun et al. [4]. Surgical management of recurrence is debatable due to a need for high-level evidence [8]. Repeat discectomy remains the main procedure for it, with only minimal improvement often reported in the patient’s clinical condition as compared to the primary surgery [13]. There also remains risk of further instability. Therefore, many authors advocate the use of instrumented spinal fusion with repeat discectomy, despite the absence of instability at the time of recurrence [14]. Residual Disc A residual disc is defined as the disc material that remains at the symptomatic operated level after the extruded fragment has been removed and enough decompression has been achieved (Fig. 2). The residual disc material may cause painful radicular symptoms to persist post-operatively, with patients complaining of inadequate relief. Such patients require re-operation. Discectomy usually involves removal of only the herniated disc material and decompression of the nerve roots, leaving the remaining disc in situ. However, this may cause more disc material to come out and recompress or inflame the nerve roots [15]. To deal with this, Aoyama et al. used intraoperative ultrasound to differentiate between nerve roots and disc material in 30 patients. By this method, they were able to confirm the adequacy of decompression in all 30 patients and also identified residual disc material in 2 patients which they were able to remove satisfactorily [15]. However, it was found to be more useful for patients with a large surgical field undergoing procedures such as removal of spinal tumors or arachnoid cysts to check the remaining fragments [16]. In 2.8–15% of patients undergoing percutaneous endoscopic lumbar discectomy (PELD), residual disc fragments were observed on immediate post-operative MRI [5]. Although the presence of a residual disc fragment with persistent compression is a reason for reoperation, not all residual disc fragments observed on immediate post-operative MRI are symptomatic (i.e., they are clinically silent). Only 1.3% of patients with residual disc tissue had to go for repeat discectomy [17]. In a retrospective study by Baek et al., the long-term clinical outcomes of PELD patients in whom complete disc fragment removal was achieved (complete group) were compared with those in whom residual fragments were detected on post-operative MRI (residual group). Early reoperation (within the first 3 post-operative months) was performed in 3 patients in the residual group (7.9%) and 4 patients in the complete group (2.1%). They concluded that in patients with asymptomatic disc remnants, “watchful waiting” can be performed instead of immediate re-exploration [17]. Careful examination of post-operative MRI findings (within 24 h of surgery) revealed that some of the disc-like material was actually edematous tissue due to the fluid used during surgery. Therefore, analysis of T1-weighted MRI images is preferable, before taking up the patient for an unnecessary repeat surgery [18]. Retained Disc Retained disc is the one at same level where only nerve root decompression or deroofing was considered assuming that it should give symptomatic relief. Also retained disc can be dealing with two level discs where only one level disc is removed or decompressed and the other disc is kept as it assuming it will not create symptoms. (Fig. 3) In both the above mentioned scenarios, the discs which were untreated/ retained creates symptoms after a while because of worsening of disc or extrusion. Though this was thought to be uncommon, this entity is seen at many instances which is the Retained disc variation. Therefore, supervised neglect of the retained disc carries its risks. Careful clinical examination is important to differentiate retained disc from recurrence. . Conclusion: Clinical examination of the patient plays a crucial role in identifying the level of radiculopathy. Dermatomal pain in the same region after discectomy often indicates recurrence, whereas pain in an adjacent or new dermatomal distribution could be due to the retained disc. MRI findings help to confirm the pathological level and differentiate between a recurrent and retained disc. Understanding the different types of disc re-herniations is important in deciding treatment options such as physiotherapy, nerve root block, and surgical modalities.

Lumbar endplate microfracture injury induces Modic-like changes, intervertebral disc degeneration and spinal cord sensitization - an in vivo rat model

BACKGROUND CONTEXT

Endplate (EP) injury plays critical roles in painful IVD degeneration since Modic changes (MCs) are highly associated with pain. Models of EP microfracture that progress to painful conditions are needed to better understand pathophysiological mechanisms and screen therapeutics.

PURPOSE

Establish in vivo rat lumbar EP microfracture model and assess crosstalk between IVD, vertebra and spinal cord.

STUDY DESIGN/SETTING

In vivo rat EP microfracture injury model with characterization of IVD degeneration, vertebral remodeling, spinal cord substance P (SubP), and pain-related behaviors.

METHODS

EP-injury was induced in 5 month-old male Sprague-Dawley rats L4-5 and L5-6 IVDs by puncturing through the cephalad vertebral body and EP into the NP of the IVDs followed by intradiscal injections of TNFα (n=7) or PBS (n=6), compared with Sham (surgery without EP-injury, n=6). The EP-injury model was assessed for IVD height, histological degeneration, pain-like behaviors (hindpaw von Frey and forepaw grip test), lumbar spine MRI and μCT, and spinal cord SubP.

RESULTS

Surgically-induced EP microfracture with PBS and TNFα injection induced IVD degeneration with decreased IVD height and MRI T2 signal, vertebral remodeling, and secondary damage to cartilage EP adjacent to the injury. Both EP injury groups showed MC-like changes around defects with hypointensity on T1-weighted and hyperintensity on T2-weighted MRI, suggestive of MC type 1. EP injuries caused significantly decreased paw withdrawal threshold, reduced axial grip, and increased spinal cord SubP, suggesting axial spinal discomfort and mechanical hypersensitivity and with spinal cord sensitization.

CONCLUSIONS

Surgically-induced EP microfracture can cause crosstalk between IVD, vertebra, and spinal cord with chronic pain-like conditions.

CLINICAL SIGNIFICANCE

This rat EP microfracture model was validated to induce broad spinal degenerative changes that may be useful to improve understanding of MC-like changes and for therapeutic screening.

Risk factors for lumbar disc herniation recurrence after percutaneous endoscopic lumbar discectomy: a meta-analysis of 58 cohort studies

Recurrent lumbar disc herniation (rLDH) is one of the most serious complications and major causes of surgical failure and paralysis following percutaneous endoscopic lumbar discectomy (PELD). There are reports in the literature on the identification of risk factors associated with rLDH; however, the results are controversial. Therefore, we conducted a meta-analysis to identify risk factors for rLDH among patients following spinal surgery. PubMed, EMBASE, and the Cochrane Library were searched without language restrictions from inception to April 2018 for studies reporting risk factors for LDH recurrence after PELD. MOOSE guidelines were followed in this meta-analysis. We used a random effects model to aggregate odds ratios (ORs) with 95% confidence intervals (CIs). The evidence of observational studies was classified into high quality (class I), medium quality (class II/III), and low quality (class IV) based on the P value of the total sample size and heterogeneity between studies. Fifty-eight studies were identified with a mean follow-up of 38.8 months. Studies with high-quality (class I) evidence showed that postoperative LDH recurrence after PELD was significantly correlated with diabetes (OR, 1.64; 95% CI, 1.14 to 2.31), the protrusion type LDH (OR, 1.62; 95% CI, 1.02 to 2.61), and less experienced surgeons (OR, 1.54; 95% CI, 1.10 to 2.16). Studies with medium-quality (class II or III) evidence showed that postoperative LDH recurrence was significantly correlated with advanced age (OR, 1.11; 95% CI, 1.05 to 1.19), Modic changes (OR, 2.23; 95% CI, 1.53 to 2.29), smoking (OR, 1.31; 95% CI, 1.00 to 1.71), no college education (OR, 1.56; 95% CI, 1.05 to 2.31), obesity (BMI ≥ 25 kg/m²) (OR, 1.66; 95% CI, 1.11 to 2.47), and inappropriate manual labor (OR, 2.18; 95% CI, 1.33 to 3.59). Based on the current literature, eight patient-related and one surgery-related risk factor are predictors of postoperative LDH recurrence after PELD. These findings may help clinicians raise awareness of early intervention for patients at high risk of LDH recurrence after PELD.

Development and Validation of a Nomogram to Predict the Risk of Lumbar Disk Reherniation within 2 Years After Percutaneous Endoscopic Lumbar Discectomy

OBJECTIVE

To develop and validate a nomogram for predicting recurrent lumbar disk herniation (LDH) within 2 years after percutaneous endoscopic lumbar discectomy.

METHODS

Information on patients' LDH was collected from 1 medical center between January 2015 and September 2020. The LASSO (least absolute shrinkage and selection operator) method was applied to select the most significant risk factors. A multivariate logistic regression analysis was used to develop a predictive model incorporating the possible factors selected by the LASSO regression model. The discriminant, corrected, and clinically useful prediction models were evaluated using consistency index (C-index), receiver operating characteristic curve, calibration curves, and decision curve analysis. Internal validation of clinical predictive power was also assessed by bootstrap validation.

RESULTS

A total of 690 patients with LDH were included in this study. Sixty-three patients experienced recurrence within 2 years whereas 627 experienced no recurrence. The nomogram predictors included age, body mass index, Modic change, Pfirrmann grade, and sagittal range of motion. The model had good discrimination power, with a reliable C-index of 0.868 (95% confidence interval, 0.822-0.913) and interval validation confirmed a higher C-index value of 0.846. The area under the receiver operating characteristic curve was 0.868, indicating a good predictive value. The decision curve analysis indicated that it was clinically feasible to use the predictive recurrence nomogram model.

CONCLUSIONS

We developed and validated a new accurate and effective nomogram for predicting recurrent LDH within 2 years after percutaneous endoscopic lumbar discectomy. Age, body mass index, Modic change, Pfirrmann grade, and sagittal range of motion were significant features for predicting rLDH.

Perioperative Management for Full-Endoscopic Lumbar Discectomy: Consideration From the Perspective of Preventing Complication

In recent years, full-endoscopic discectomy (FED) has expanded its range of indications with the development of devices and various techniques. The advantage of FED over conventional surgery is that it is a minimally invasive procedure. However, intraoperative and postoperative precautions must be taken to prevent complications. It is necessary to avoid complications that could compromise the outcome of the procedure. Effective perioperative management is necessary to avoid complications; however, there is no set view for perioperative management in FED. In this study, we perform a literature review to examine the effectiveness of perioperative management methods for FED. The key to ensuring the efficacy and minimal invasiveness of FED is prevention of complications. Based on the result and literature review, we believe that the most manageable postoperative management after FED is prevention of recurrent disc herniation and hematoma formation. A drain should be placed to prevent postoperative hematoma formation. It is advisable to evaluate the patient’s symptoms and monitor C-reactive protein and erythrocyte sedimentation rate levels during the first week after surgery. Postoperative antibiotics were administered for 1 day.

Lumbar endplate microfracture injury induces Modic-like changes, intervertebral disc degeneration and spinal cord sensitization - An In Vivo Rat Model

BACKGROUND CONTEXT : Endplate (EP) injury plays critical roles in painful IVD degeneration since Modic changes (MCs) are highly associated with pain. Models of EP microfracture that progress to painful conditions are needed to better understand pathophysiological mechanisms and screen therapeutics. PURPOSE : Establish in vivo rat lumbar EP microfracture model with painful phenotype. STUDY DESIGN/SETTING : In vivo rat study to characterize EP-injury model with characterization of IVD degeneration, vertebral bone marrow remodeling, spinal cord sensitization, and pain-related behaviors. METHODS : EP-driven degeneration was induced in 5-month-old male Sprague-Dawley rats L4-5 and L5-6 IVDs through the proximal vertebral body injury with intradiscal injections of TNFα (n=7) or PBS (n=6), compared to Sham (surgery without EP-injury, n=6). The EP-driven model was assessed for IVD height, histological degeneration, pain-like behaviors (hindpaw von Frey and forepaw grip test), lumbar spine MRI and μCT analyses, and spinal cord substance P (SubP). RESULTS : EP injuries induced IVD degeneration with decreased IVD height and MRI T2 values. EP injury with PBS and TNFα both showed MC type1-like changes on T1 and T2-weighted MRI, trabecular bone remodeling on μCT, and damage in cartilage EP adjacent to the injury. EP injuries caused significantly decreased paw withdrawal threshold and reduced grip forces, suggesting increased pain sensitivity and axial spinal discomfort. Spinal cord dorsal horn SubP was significantly increased, indicating spinal cord sensitization. CONCLUSIONS : EP microfracture can induce crosstalk between vertebral bone marrow, IVD and spinal cord with chronic pain-like conditions. CLINICAL SIGNIFICANCE : This rat EP microfracture model of IVD degeneration was validated to induce MC-like changes and pain-like behaviors that we hope will be useful to screen therapies and improve treatment for EP-drive pain.

Clinical efficacy of transforaminal endoscopic discectomy in the treatment of recurrent lumbar disc herniation: a single-center retrospective analysis

PURPOSE

To investigate the clinical efficacy of transforaminal endoscopic discectomy (TED) in treating recurrent lumbar disc herniation.

METHODS

Clinical datal of 31 patients who were hospitalized in the Department of Pain Management, First Affiliated Hospital of Nanchang University, between 2015 and 2018 due to recurrent lumbar disc herniation were collected and analyzed retrospectively. Visual analogue scale (VAS) scores and Japanese Orthopedic Association (JOA) scores were used to assess alterations of patients' leg pain intensity and nerve function, respectively. The Modified MacNab criteria were used to evaluate patients' excellent and good rates.

RESULTS

Compared to clinical data before surgery, there was a significant reduction in VAS scores (P < 0.01) along with a significant improvement in JOA scores (P < 0.01) at 2 years after revision surgery. The patients' excellent and good rates were 83.9% at the 2 years after surgery.

CONCLUSION

The TED is safe and effective in the long term and is applicable to the treatment of recurrent lumbar disc herniation.

Identification of preoperative radiological risk factors for reoperation following percutaneous endoscopic lumbar decompression to treat degenerative lumbar spinal stenosis

Background

This study aimed to identify radiological risk factors associated with reoperation after percutaneous transforaminal endoscopic decompression (PTED) for degenerative lumbar spinal stenosis (DLSS).

Methods

The preoperative clinical data of 527 consecutive patients with DLSS who underwent PTED were retrospectively reviewed. Overall, 44 patients who underwent reoperation were matched for age, sex, body mass index, and surgical segment to 132 control patients with excellent or good clinical outcomes. Radiological characteristics were compared between the groups using independent sample t-tests and Pearson's chi-square tests. A predictive model was established based on multivariate logistic regression analysis.

Results

The analyses revealed significant differences in the presence of lumbosacral transitional vertebra (LSTV, 43.2% vs. 17.4%, p = 0.001), the number of levels with senior-grade disc degeneration (2.57 vs. 1.96, p = 0.018) and facet degeneration (1.91 vs. 1.25 p = 0.002), and the skeletal muscle index (SMI, 849.7 mm²/m² vs. 1008.7 mm²/m², p < 0.001) between patients in the reoperation and control groups. The results of the logistic analysis demonstrated that LSTV (odds ratio [OR] = 2.734, 95% confidence interval [CI]:1.222-6.117, p < 0.014), number of levels with senior-grade facet degeneration (OR = 1.622, 95% CI:1.137-2.315, p = 0.008), and SMI (OR = 0.997, 95% CI:0.995-0.999, p = 0.001) were associated with reoperation after PTED. The application of the nomogram based on these three factors showed good discrimination (area under the receiver operating characteristic curve 0.754, 95% CI 0.670-0.837) and good calibration.

Conclusion

LSTV, more levels with senior-grade facet degeneration, and severe paraspinal muscle atrophy are independent risk factors for reoperation after PTED. These factors can thus be used to predict reoperation risk and to help tailor treatment plans for patients with DLSS.

Immune exposure: how macrophages interact with the nucleus pulposus

Intervertebral disc degeneration (IDD) is a primary contributor to low back pain. Immune cells play an extremely important role in modulating the progression of IDD by interacting with disc nucleus pulposus (NP) cells and extracellular matrix (ECM). Encased within the annulus fibrosus, healthy NP is an avascular and immune-privileged tissue that does not normally interact with macrophages. However, under pathological conditions in which neovascularization is established in the damaged disc, NP establishes extensive crosstalk with macrophages, leading to different outcomes depending on the different microenvironmental stimuli. M1 macrophages are a class of immune cells that are predominantly pro-inflammatory and promote inflammation and ECM degradation in the NP, creating a vicious cycle of matrix catabolism that drives IDD. In contrast, NP cells interacting with M2 macrophages promote disc tissue ECM remodeling and repair as M2 macrophages are primarily involved in anti-inflammatory cellular responses. Hence, depending on the crosstalk between NP and the type of immune cells (M1 vs. M2), the overall effects on IDD could be detrimental or regenerative. Drug or surgical treatment of IDD can modulate this crosstalk and hence the different treatment outcomes. This review comprehensively summarizes the interaction between macrophages and NP, aiming to highlight the important role of immunology in disc degeneration.

The Thermosensitive Injectable Celecoxib-Loaded Chitosan Hydrogel for Repairing Postoperative Intervertebral Disc Defect

Percutaneous endoscopic lumbar discectomy has been widely used in clinical practice for lumbar spine diseases. But the postoperative disc re-herniation and inflammation are the main reason for pain recurrence after surgery. The postoperative local defect of the intervertebral disc will lead to the instability of the spine, further aggravating the process of intervertebral disc degeneration. In this work, we successfully synthesized the thermosensitive injectable celecoxib-loaded chitosan hydrogel and investigated its material properties, repair effect, biocompatibility, and histocompatibility in in vitro and in vivo study. In vitro and in vivo, the hydrogel has low toxicity, biodegradability, and good biocompatibility. In an animal experiment, this composite hydrogel can effectively fill local tissue defects to maintain the stability of the spine and delay the process of intervertebral disc degeneration after surgery. These results indicated that this composite hydrogel will be a promising way to treat postoperative intervertebral disc disease in future clinical applications.

Risk Factors and Surgical Management of Recurrent Herniation after Full-Endoscopic Lumbar Discectomy Using Interlaminar Approach

Full-endoscopic lumbar discectomy (FED) is one of the least invasive procedures for lumbar disc herniation. Patients who receive FED for lumbar disc herniation may develop recurrent herniation at a frequency similar to conventional procedures. Reoperation and risk factors of recurrent lumbar disc herniation were investigated among 909 patients who received FED using an interlaminar approach (FED-IL). Sixty-five of the 909 patients received reoperation for recurrent herniation. Disc height, smoking, diabetes mellitus (DM), subligamentous extrusion (SE) type, and Modic change were identified as the risk factors for recurrence. Other indicators such as LL, Cobb angle, disc migration, age, sex, and body mass index (BMI) did not reach significance. Among 65 patients, reoperation was performed within 14 days following FED-IL (very early) in 7 patients, from 15 days to 3 months (early) in 14 patients, from 3 months to 1 year (midterm) in 17 patients, and after more than 1 year (late) in 27 patients. The very early group included a greater number of males, and the mean age was significantly lower in comparison to other groups. All patients in the very early group received FED-IL for reoperation. Reoperation within 2 weeks allows FED-IL to be performed without adhesion. Fusion surgery was performed on three cases in the early and midterm groups and on 10 cases in the late group, which increased over time as degenerative change and adhesion progressed. The procedure selected to treat recurrent herniation mostly depends on the surgeon’s preference. Revision FED-IL is the first choice for recurrent herniation in terms of minimizing surgical burden, whereas fusion surgery offers the advantage that discectomy can be performed through unscarred tissues. FED-IL is recommended for recurrent herniation within 2 weeks before adhesion progresses.

Incidence of recurrent lumbar disc herniation: A narrative review

Background:

Recurrent disc herniation is a common condition that often results in months of disabling symptoms and additional costs.

Objective:

The objective of this study was to investigate the incidence of recurrent disc herniation in patients treated surgically.

Materials and Methods:

Clinical trials and prospective studies involving patients treated with different techniques, such as open, percutaneous, or microendoscopic discectomy, were included. The incidence of recurrence as well as the level and the time until the recurrent disc herniation was collected.

Results:

Thirteen studies were included. Recurrence of disc herniation ranged from 0% to 14% of patients. Most recurrences occurred at the same level of herniation and on the same side. The time to recurrence of disc herniation ranged from 1 to 5 years.

Conclusion:

This study answers the question of how much, when, and where in lumbar recurrent disc herniation.

Adjuvant surgical decision-making system for lumbar intervertebral disc herniation after percutaneous endoscopic lumber discectomy: a retrospective nonlinear multiple logistic regression prediction model based on a large sample

BACKGROUND CONTEXT

Lumbar disc herniation (LDH) is a common condition that can affects an individual' quality of life. In patients for whom conservative treatment is ineffective after 3 months, surgical treatment, such as percutaneous endoscopic lumbar discectomy (PELD), is recommended. Because PELD is minimally invasive and produces thorough nerve root decompression, both surgeons and patients often prefer it to other techniques.

PURPOSE

Surgeons find it challenging to prevent postoperative recurrent LDH (rLDH) when they use PELD. We created and verified a model for evaluating patients' recurrence risk factors before surgery so that surgeons can choose other surgical techniques when necessary.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

One thousand eight hundred seven patients who underwent PELD at our hospital between 2012 and 2015 were enrolled.

OUTCOME MEASURE

The main outcome measure was rLDH at any follow-up time point.

METHODS

Data were retrospectively analyzed for 1807 patients who underwent PELD at our hospital at some point between 2012 and 2015; all patients had been monitored for at least 5 years after surgery. They were divided into a recurrence group and a nonrecurrence group. Clinical and radiological risk factors were assessed over time to determine their correlations with recurrence and to exclude less important factors. A nonlinear multivariate logistic regression model was established to predict the recurrence rate before surgery.

RESULTS

A total of 1706 patients were monitored after PELD; data were missing for 101 additional patients. The total recurrence rate was 10.38%, and the most common time from surgery to recurrence was 1 year. Ten risk factors were assessed and included in the analysis. Regarding clinical risk factors, patients with hypertension (p < .001; correlation coefficient R [R] = 0.235; odds ratio [OR] = 4.749), diabetes (p < .001; R = 0.381; OR = 16.797), a history of smoking (p < .001; R = 0.347; OR = 9.012), and a history of performing intense physical labor (p < .001; R = 0.409; OR = 19.592) had a higher recurrence rate. Regarding radiological risk factors, patients with disc degeneration (Pfirrmann grade III) (p < .001; R = 0.228; OR = 4.919), Modic changes (level 2) (p < .001; R = 0.309; OR = 7.934), herniation in the form of extrusion (p < .001; R = 0.365; OR = 12.228), a higher disc height index (DHI) (p < .001; R = 0.336), and a larger segmental range of motion (p < .001; R = 0.243) had a higher recurrence rate. When the lumbar motion angle was negative (p < .001; R = 0.318; OR = 13.680), the recurrence rate was high. The overall accuracy of the final model was 97.6% (1665 of 1706). The recognition rate for non-rLDH cases was 99.0% (1514 of 1529), and the rate for rLDH cases was 85.3% (151 of 177); the AUC was 0.9315. A simple model was used. For those patients with postoperative trauma (p < .001; R = 0.382; OR = 13.680), a comparison model was established, and the corresponding recurrence rate was 23.0% ± 25.0% (0-76%).

CONCLUSIONS

A large cohort of patients underwent long-term monitoring, and 11 risk factors were verified for assessing each patient's risks before surgery to predict the postoperative recurrence of LDH following PELD. The risk of recurrence may be effectively reduced with the use of alternative surgical techniques in high risk cases.

Comparison of Percutaneous Transforaminal Endoscopic Decompression and Transforaminal Lumbar Interbody Fusion in the Treatment of Single-Level Lumbar Disc Herniation with Modic Type I Changes

Background

Modic changes (MC) are generally considered to be related to degenerative disc disease, and there is no uniform standard for surgical methods for lumbar disc herniation (LDH) accompanied by Modic type I changes (MC I). The purpose of this study was to observe the clinical results of percutaneous transforaminal endoscopic decompression (PTED) and transforaminal lumbar interbody fusion (TLIF) for treatment of LDH accompanied by MC I.

Methods

Of the 53 consecutive patients included, 29 underwent PTED and 24 underwent TLIF. All patients were followed up for at least 24 months. Preoperative demographic characteristics, perioperative outcomes, and clinical outcomes were recorded. Visual analog scale (VAS) scores, Oswestry disability index (ODI) scores, and modified Macnab criteria were used to assess clinical results.

Results

The mean age was 53.7±9.2 years in the PTED group and 53.6±9.6 years in the TLIF group. The scores of VAS legs, VAS back and ODI in the two groups after operation were significantly improved compared with those before operation (P<0.05). Notably, the VAS back pain score and ODI in the PTED group showed an increasing trend with time. And the VAS back pain scores and ODI of the two groups were statistically different at 1 year and 2 years postoperatively (P<0.05). In addition, compared with the TLIF group, the PTED group showed less operation time, blood loss, and postoperative hospital stay (P<0.05). At the final follow-up, the excellent rates were 91.7% and 86.2% in the fusion and PTED groups, respectively.

Conclusion

Both PTED and TLIF procedures significantly improved the clinical symptoms of single-level LDH patients with MC I. Compared with TLIF, MC I may affect the improvement of low back pain and functional status after PTED.