Nomograms for Predicting Recurrent Herniation in PETD with Preoperative Radiological Factors

Development of a Dual-Plane MRI-Based Deep Learning Model to Assess the 1-Year Postoperative Outcomes in Lumbar Disc Herniation After Tubular Microdiscectomy

BACKGROUND

Tubular microdiscectomy (TMD) is a treatment for lumbar disc herniation (LDH). Although the combination of MRI and deep learning (DL) has shown promise, its application in evaluating postoperative outcomes in TMD has not been fully explored.

PURPOSE/HYPOTHESIS

To evaluate whether integrating preoperative dual-plane MRI-based DL features with clinical features can assess 1-year outcomes in TMD for LDH.

STUDY TYPE

Retrospective.

POPULATION/SUBJECTS

The study involved 548 patients who underwent TMD between January 2016 and January 2021. Training set (N = 305, mean age 51.85 ± 13.84 years, 56.4% male). Internal validation set (N = 131, mean age 51.85 ± 13.84 years, 54.2% male). External validation set (N = 112, mean age 51.54 ± 14.43 years, 50.9% male).

FIELD STRENGTH/SEQUENCE

3 T MRI with sagittal and transverse T2-weighted sequences (Fast Spin Echo).

ASSESSMENT

Ground truth labels were based on improvement rate in 1-year Japanese Orthopaedic Association (JOA) scores. Information on 42 preoperative clinical features was collected. The largest protrusions were identified from T2 MRI by three clinicians and were used to train deep learning models (ResNet50, ResNet101, and ResNet152) to extract DL features. After feature selection, three models were built, namely, clinical, DL, and combined models.

STATISTICAL TESTS

Chi-square or Fisher's exact tests was used for group comparisons. Quantitative differences were analyzed using the t-test or Mann-Whitney U test. P-values <0.05 were considered significant. Models were validated on internal and external datasets using metrics such as the area under the curve (AUC).

RESULTS

The AUCs of the clinical models achieved 0.806 (internal) and 0.779 (external). ResNet152 performed best in three DL models, with AUCs of 0.858 (internal) and 0.834 (external). The combined model achieved AUCs of 0.889 (internal) and 0.857 (external).

DATA CONCLUSION

A model combining preoperative dual-plane MRI DL features and clinical features can assess 1-year outcomes of TMD for LDH.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

Development of Modic Changes After Percutaneous Endoscopic Transforaminal Lumbar Discectomy: From Risk Analysis to Prediction Modeling

Objective

This study examines the occurrence of Modic changes (MC) within the first year following percutaneous endoscopic transforaminal lumbar discectomy (PETD) and investigates associated risk factors.

Methods

This study adopted a retrospective cohort design. Between January 2019 and June 2023, 538 patients diagnosed with single-level lumbar disc herniation and treated with PETD were included. The patients were divided into a training set and a validation set based on their surgery dates. Preoperative radiographic parameters and perioperative indicators were evaluated. Univariate analysis examined risk factors for postoperative MC. Gender-specific subgroups were analyzed. Binary logistic regression developed a predictive model for postoperative MC, assessed using ROC, calibration, and decision curves.

Results

The incidence of MC at one year after PETD was 24.8%. Logistic regression identified 8 significant risk factors for MC after PELD: longer symptom duration, proximity of herniated segment to sacrum, severe disc degeneration, reduced disc height, greater vertebral endplate concavity angle, segmental instability, and lumbar-sacral fusion. Menopause and herniation type were identified as female-specific risk factors. In males, total cholesterol levels were additionally found to be a risk factor for postoperative MC. The male and female subgroup models exhibited satisfactory performance across ROC analysis, calibration plots, and decision curve analysis. Specifically, for male patients, the area under the curve (AUC) was 0.831 for the training set and 0.820 for the validation set; for female patients, the AUC was 0.911 for the training set and 0.868 for the validation set. A nomogram was developed to visualize the model.

Conclusion

This study explored the relevant risk factors of MC after PETD and visualized the prediction model by nomogram, which is beneficial to optimize the surgical scheme of PETD to improve the clinical efficacy.

Radiomics based on MRI to predict recurrent L4-5 disc herniation after percutaneous endoscopic lumbar discectomy

BACKGROUND

In recent years, radiomics has been shown to be an effective tool for the diagnosis and prediction of diseases. Existing evidence suggests that imaging features play a key role in predicting the recurrence of lumbar disk herniation (rLDH). Thus, this study aimed to evaluate the risk of rLDH in patients undergoing percutaneous endoscopic lumbar discectomy (PELD) using radiomics to facilitate the development of more rational surgical and perioperative management strategies.

METHOD

This was a retrospective case-control study involving 487 patients who underwent PELD at the L4/5 level. The rLDH and negative groups were matched using propensity score matching (PSM). A total of 1409 radiomic features were extracted from preoperative lumbar MRI images using intraclass correlation coefficient (ICC) analysis, t-test, and LASSO analysis. Afterward, 6 predictive models were constructed and evaluated using ROC curve analysis, AUC, specificity, sensitivity, confusion matrix, and 2 repeated 3-fold cross-validations. Lastly, the Shapley Additive Explanation (SHAP) analysis provided visual explanations for the models.

RESULTS

Following screening and matching, 128 patients were included in both the recurrence and control groups. Moreover, 18 of the extracted radiomic features were selected for generating six models, which achieved an AUC of 0.551-0.859 for predicting rLDH. Among these models, SVM, RF, and XG Boost exhibited superior performances. Finally, cross-validation revealed that their accuracy was 0.674-0.791, 0.647-0.729, and 0.674-0.718.

CONCLUSION

Radiomics based on MRI can be used to predict the risk of rLDH, offering more comprehensive guidance for perioperative treatment by extracting imaging information that cannot be visualized with the naked eye. Meanwhile, the accuracy and generalizability of the model can be improved in the future by incorporating more data and conducting multicenter studies.

Endoscopic Revision Strategies and Outcomes for Recurrent L4/5 Disc Herniation After Percutaneous Endoscopic Transforaminal Discectomy

Objective

We explore the endoscopic revision and surgical techniques for L4/5 recurrent disc herniation (rLDH) after percutaneous endoscopic transforaminal discectomy (PETD).

Methods

A retrospective study was conducted. From January 2016 to September 2022, 96 patients who underwent percutaneous endoscopic lumbar discectomy for L4/5 rLDH after PETD were enrolled in the study. Based on the revision approach, the patients were divided into PETD group (57 cases) and percutaneous endoscopic interlaminar discectomy (PEID) group (39 cases). Visual Analogue Scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and modified MacNab standard were recorded to evaluate the clinical outcomes.

Results

No significant differences were found in the demographic data and intraoperative blood loss between the two groups (P>0.05), but the time of operation and intraoperative X-ray fluoroscopy exposures in the PEID group were significantly less than that in the PETD group (P<0.05). The patients' postoperative clinical indexes gradually improved, and the VAS score, ODI index, and JOA score of the patients in both groups showed significant improvement compared with the preoperative period at the 1-week, 1-month, and 6-month postoperative follow-ups (P < 0.05). There was no serious complication observed during the follow-up.

Conclusion

For recurrent LDH after PETD of L4/5 segments, percutaneous endoscopic revision can achieve satisfactory results. Among them, PEID has a shorter operative and fluoroscopy time and allows avoidance of the scar that forms after the initial surgery, so it can be considered preferred when both procedures can remove the disk well. However, for some specific types of herniation, a detailed surgical strategy is required.

Association of spinal-pelvic parameters with recurrence of lumbar disc herniation after endoscopic surgery: a retrospective case-control study

PURPOSE

This study aimed to investigate the relationship between spinal-pelvic parameters and recurrence of lumbar disc herniation (rLDH) after percutaneous endoscopic lumbar discectomy (PELD) through a retrospective case-control study.

METHODS

Patients who underwent PELD for single-segment LDH at our hospital were included in this study. The relationship between sagittal balance parameters of the spine and recurrence was analysed through correlation analysis, and ROC curves were plotted. The baseline characteristics, sagittal balance parameters of the spine and radiological parameters of the case and control groups were compared, and the relationship between sagittal balance parameters of the spine and recurrence of rLDH after PELD was determined through univariate and multivariate logistic regression analysis.

RESULTS

Correlation analysis showed that PI and ∆PI-LL were negatively correlated with grouping (r = -0.090 and -0.120, respectively, P = 0.001 and 0.038). ROC curve analysis showed that the area under the curve (ROC-AUC) for predicting rLDH based on PI was 0.65 (CI95% = 0.598, 0.720), with a cut-off of 50.26°. The ROC-AUC for predicting rLDH based on ∆PI-LL was 0.56 (CI95% = 0.503, 0.634), with a cut-off of 28.21°. Multivariate logistic regression analysis showed that smoking status (OR = 2.667, P = 0.008), PI ≤ 50.26 (OR = 2.161, P = 0.009), ∆PI-LL ≤ 28.21 (OR = 3.185, P = 0.001) and presence of Modic changes (OR = 4.218, P = 0.001) were independent risk factors, while high DH (OR = 0.788, P = 0.001) was a protective factor.

CONCLUSION

PI < 50.26 and ∆PI-LL < 28.21 were risk factors for recurrence of lumbar disc herniation after spinal endoscopic surgery and had some predictive value for post-operative recurrence.

Risk factors for ninety-day readmissions following full-endoscopic transforaminal lumbar discectomy for 1542 patients in the biggest spine institutes in Korea

INTRODUCTION

Endoscopic techniques are becoming popular among spine surgeons because of their advantages. Though the advantages of endoscopic spine surgery are evident and patients can be discharged home within hours of surgery, readmissions can be sought for incomplete relief of leg pain, recurrent disc herniation, and recurrent leg pain. We aim to find out the factors related to the readmission of patients treated for lumbar pathologies.

MATERIALS AND METHODS

This is a retrospective analysis of the data between the time duration of 2012 and 2022. Patients in the age group of 18-85 years, with lumbar disc herniation treated by transforaminal endoscopic lumbar procedures, were included. The patients who were readmitted within 90 days were included in the R Group and those who were not were included in the NR group. Univariable and multivariable logistic regression analyses were used to find the risk factors for 90-day readmission.

RESULTS

There were a total of 1542 patients enrolled in this study. Sex, number of episodes before admission, hypertension, smoking, BMI, migration, disc height, disc height index, spondylolisthesis, instability, pelvic tilt (PT), and disc cross-sectional area (CSA) were found significant on univariable analysis. Age, spondylolisthesis, instability and muscle CSA were the only variables that were found to be statistically significant on multivariable analysis.

CONCLUSIONS

This study shows that the elderly age group, presence of spondylolisthesis, segmental instability and decreased muscle cross-sectional area are independent risk factors for 90-day hospital readmissions. Patients having the above risk factors should be carefully counseled regarding the possibility of readmission in the future.

Efficacy of Transforaminal Endoscopic Lumbar Discectomy in Elderly Patients Over 65 Years of Age Compared to Young Adults

OBJECTIVE

Spine surgery rates are increasing in the elderly population due to social aging, and it is known that prognoses related to surgery are worse for the elderly compared to younger individuals. However, minimally invasive surgery, such as full endoscopic surgery, is considered safe with low complication rates due to minimal damage to surrounding tissues. In this study, we compared outcomes of transforaminal endoscopic lumbar discectomy (TELD) in elderly and younger patients with disc herniation in the lumbosacral region.

METHODS

We retrospectively analyzed the data of 249 patients who underwent TELD at a single center between January 2016 to December 2019, with a minimum follow-up of 3 years. Patients were allocated to 2 groups: a young group aged ≤ 65 years (n = 202) or an elderly group aged > 65 years (n = 47). We evaluated baseline characteristics, clinical outcomes, surgery-related outcomes, radiological outcomes, perioperative complications, and adverse events during the 3-year follow-up period.

RESULTS

Baseline characteristics, including age, general condition based on American Society of Anesthesiologist physical status classification grade, age-Charlson Comorbidity Index, and disc degeneration, were worse in elderly group (p < 0.001). However, except for leg pain at 4 weeks after surgery, overall outcomes, including pain improvement, radiological change, operation time, blood loss, and hospital stay, were not different between the 2 groups. Furthermore, the rates of perioperative complications (9 patients [4.46%] in the young group and 3 patients [6.38%] in the elderly group, p = 0.578) and adverse events over the 3-year follow-up period (32 patients [15.84%] in the young group and 9 patients [19.15%] in the elderly group, p = 0.582) were comparable in the 2 groups.

CONCLUSION

Our findings suggest that TELD produces similar outcomes in both elderly and younger patients with a herniated disc in the lumbosacral region. TELD can be considered a safe option for appropriately selected elderly patients.

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.

Recurrence of Local Kyphosis After Percutaneous Kyphoplasty: The Neglected Injury of the Disc-Endplate Complex

Background

Recurrent of local kyphosis after percutaneous kyphoplasty (PKP) is rarely reported and discussed. Literatures reported that re-kyphosis is usually a consequence of refractures of augmented or adjacent vertebra. However, whether re-kyphosis should be considered as a complication of refractures and has an impact on clinical efficacy of PKP during follow-up time is unknown. The purpose of this study is to evaluate the related risk factors and clinical significance of the recurrent of local kyphosis in osteoporotic vertebral fracture (OVF) patients without refractures.

Patients and Methods

A total of 143 patients who underwent single-level PKP were recruited and assigned into the re-kyphosis group and non-re-kyphosis group. Clinical and radiographic data were collected and compared between the two groups. Then, multivariate logistic regression analyses were conducted to identify the related risk factors.

Results

During follow-up, 16 of the 143 patients presented postoperative re-kyphosis. The average local kyphosis angle increased from 11.81±8.60° postoperatively to 25.13±8.91° at the final follow-up which showed a statistically significant difference (p<0.05). Both groups had significant improvements in postoperative visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores compared to their preoperative values (p<0.05). However, in the re-kyphosis group at final follow-up, the VAS and ODI scores showed worsening compared to the postoperative scores. Logistic regression analysis showed that disc-endplate complex injury (OR=17.46, p=0.003); local kyphosis angle correction (OR=1.84, p<0.001); and vertebral height restoration (OR=1.15, p=0.003) were risk factors for re-kyphosis.

Conclusion

Re-kyphosis is not rare in patients with osteoporotic vertebral fracture and tends to have an inferior prognosis following PKP surgery. Patients with disc-endplate complex injury and more correction of vertebral height and kyphosis angle are at a higher risk for re-kyphosis after PKP surgery than others.

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.

Development, validation, and visualization of a web-based nomogram to predict the effect of tubular microdiscectomy for lumbar disc herniation

Objective

The purpose of this study was to retrospectively collect the relevant clinical data of lumbar disc herniation (LDH) patients treated with the tubular microdiscectomy (TMD) technique, and to develop and validate a prediction model for predicting the treatment improvement rate of TMD in LDH patients at 1 year after surgery.

Methods

Relevant clinical data of LDH patients treated with the TMD technology were retrospectively collected. The follow-up period was 1 year after surgery. A total of 43 possible predictors were included, and the treatment improvement rate of the Japanese Orthopedic Association (JOA) score of the lumbar spine at 1 year after TMD was used as an outcome measure. The least absolute shrinkage and selection operator (LASSO) method was used to screen out the most important predictors affecting the outcome indicators. In addition, logistic regression was used to construct the model, and a nomogram of the prediction model was drawn.

Results

A total of 273 patients with LDH were included in this study. Age, occupational factors, osteoporosis, Pfirrmann classification of intervertebral disc degeneration, and preoperative Oswestry Disability Index (ODI) were screened out from the 43 possible predictors based on LASSO regression. A total of 5 predictors were included while drawing a nomogram of the model. The area under the ROC curve (AUC) value of the model was 0.795.

Conclusions

In this study, we successfully developed a good clinical prediction model that can predict the effect of TMD for LDH. A web calculator was designed on the basis of the model (https://fabinlin.shinyapps.io/DynNomapp/).

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.

Complications and risk factors of percutaneous endoscopic transforaminal discectomy in the treatment of lumbar spinal stenosis

Background

With the advancements in surgical methods, optical designs, and surgical instruments, percutaneous endoscopic transforaminal discectomy (PETD) has become an effective and minimally invasive procedure to treat lumbar spinal stenosis (LSS) in recent years. Few studies have focused on the complications associated with the treatment of LSS using percutaneous endoscopic lumbar discectomy (PELD). This study aimed to summarize the complications of PETD and identify the associated risk factors.

Methods

Complications in a total of 738 consecutive LSS patients who underwent single-level PETD were retrospectively recorded and analyzed between January 2016 and July 2020. In addition, a matched case-control study was designed, and according to the date of operation, the control group was matched with patients without complications, with a matching ratio of 1:3. Demographic parameters included age, sex, BMI, smoking and drinking status, comorbidity, and surgical level. The radiological parameters included grade of surgical-level disc degeneration, number of degenerative lumbar discs, grade of lumbar spinal stenosis, degenerative lumbar scoliosis, lumbar lordosis, disc angle, and disc height index. Univariate analysis was performed using independent samples t-test and chi-squared test.

Results

The incidence of different types of complications was 9.76% (72/738). The complications and occurrence rates were as follows: recurrence of LSS (rLSS), 2.30% (17/738); persistent lumbosacral or lower extremity pain, 3.79% (28/738); dural tear, 1.90% (14/738); incomplete decompression, 0.81% (6/738); surgical site infection, 0.41% (3/738); epidural hematoma, 0.27% (2/738); and intraoperative posterior neck pain, 0.27% (2/738). Univariate analysis demonstrated that age, the grade of surgical-level disc degeneration (P < 0.001) and the number of disc degeneration levels (P = 0.004) were significantly related to the complications.

Conclusion

Complications in the treatment of LSS using PELD included rLSS, persistent pain of the lumbosacral or lower extremity, dural tear, incomplete decompression, surgical site infection, epidural hematoma, and intraoperative posterior neck pain. In addition, old age, severe grade of surgical-level disc degeneration and more disc degeneration levels significantly increased the incidence of complications.

Spinal Biomechanical Modelling in the Process of Lumbar Intervertebral Disc Herniation in Middle-Aged and Elderly

Lumbar disc herniation is one of the common clinical diseases of the lower lumbar spine in orthopedics. The purpose is to remove the herniated disc nucleus pulposus tissue, remove the compressed part of the disease, and relieve symptoms, such as nerve pain. In the past, biomechanics research mostly relied on in vitro measurements, but the complicated internal environment of the human body prevented us from further measurement and research. However, with the development of computer technology, the use of computer CT scanning, software three-dimensional reconstruction, and displacement study three-dimensional spine biomechanics method makes the research of biomechanics into in vitro simulation stage and has gradually become the focus of current research. The postoperative biomechanics was simulated and the comparison model was established at the same time. At the same time, we combined the clinical follow-up data and studied the clinical data for the treatment of postoperative recurrence of lumbar disc herniation. We compared and analyzed the initial operation method and the experimental results and obtained the prevention of recurrence. The results showed that when one inferior articular process was removed, the lumbar spine appeared unstable to rotate to the opposite side; when one inferior articular process was completely removed, the movement of the lumbar spine in all directions was unstable. Better research on the biomechanical properties of the spine will help the diagnosis and treatment of clinical lumbar disc herniation. Therefore, when performing posterior lumbar spine surgery, not only should the exposure of the surgical field and thorough decompression be considered, but also the biomechanical properties of the lumbar spine should be comprehensively evaluated.