Comparison of early and late percutaneous endoscopic lumbar discectomy for lumbar disc herniation

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.

A Postoperative Phenomenon of Percutaneous Endoscopic Lumbar Discectomy: Rebound Pain

OBJECTIVE

After percutaneous endoscopic lumbar discectomy (PELD), most patients with lumbar disc herniation (LDH) experience relief from the typical symptoms of low back and leg pain. However, for a small number of patients, these symptoms are relieved immediately after surgery but aggravated soon after, and then relieved after short-term full rest or conservative treatment. The aim of the study was to demonstrate this short-term recurrent phenomenon, termed rebound pain.

METHODS

A retrospective study was conducted on 144 patients who underwent single-segment PELD from May 2017 to June 2020. Postoperative patients were divided into a rebound pain group and a non-rebound pain group. For the former group, general information, symptom characteristics and visual analogue score (VAS) changes in rebound pain were summarized. For both groups, postoperative efficacy was evaluated by recent VAS of low back and leg pain in the remission stage, the Oswestry disability index (ODI) and the modified MacNab criteria at the last follow-up. Logistic regression analysis was used to identify predictors for rebound pain.

RESULTS

The VAS and ODI exhibited significant improvements at the last follow-up of average 15.4 months (P < 0.001). The successful outcomes according to the modified MacNab criteria reached 94.4%. A total of 15 patients (10.4%) experienced rebound pain. The typical feature was pain that usually began within 1 month after surgery and lasted for less than 1 month. The symptoms were mainly leg pain with or without low back pain. The range of pain was equal to or less than that before surgery. The symptoms were relieved after conservative treatment. In logistic regression model, postoperative return-to-work time > 45 days was found as a protective factor for rebound pain (p = 0.031).

CONCLUSION

Although rebound pain with multiple characteristics and a short duration had no significant effect on long-term postoperative efficacy, its high incidence often caused unnecessary concern in both patients and doctors. As a result, careful differentiation of rebound pain from other postoperative complications is needed.

Improvements in Back and Leg Pain Following a Minimally Invasive Transforaminal Lumbar Interbody Fusion

BACKGROUND

Improvement in patient-reported outcomes after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) is poorly defined. As such, the purpose of this study was to quantify improvements in Visual Analogue Scale back and leg pain, Oswestry Disability Index (ODI), and Short Form-12 (SF-12) Mental and Physical Composite scores following MIS-TLIF.

METHODS

A surgical registry of patients who underwent primary 1-level MIS-TLIF during 2014-2015 was reviewed. Comparisons of Visual Analogue Scale back and leg pain, ODI, and Short Form-12 Mental and Physical Composite scores were performed using paired t tests from preoperative to each postoperative time point. Analysis of variance was used to estimate the degree of improvement in back and leg pain over the first postoperative year. Subgroup analysis was performed for patients presenting with predominant back (pBP) or leg (pLP) pain. Multivariate linear regression was performed to compare patient-reported outcome scores by subgroup.

RESULTS

A total of 106 patients were identified. Visual Analogue Scale back and leg scores, and ODI improved from preoperative scores at all postoperative time points (P < .05 for each). Patients with pBP (n = 68) and patients with pLP (n = 38) reported reductions in both back and leg pain over the first postoperative year (P < .05 for each). In the pBP cohort, patients experienced significant reductions in ODI after the first 6 postoperative weeks (P < .05 for each). In the pLP cohort, patients experienced significant reductions in ODI throughout the first postoperative year (P < .05 for each). Patients with pLP and pBP experienced similar reductions in back pain, whereas patients with pLP experienced significantly greater reductions in leg pain at all postoperative time points (P < .05 for each).

CONCLUSIONS

The current study suggests patients experience significant improvements in back and leg pain following MIS-TLIF regardless of predominant symptom.

CLINICAL RELEVANCE

These results can assist surgeons when counseling their patients on the magnitude of symptom improvement they may experience following MIS-TLIF.

Surgical outcomes of full endoscopic spinal surgery for lumbar disc herniation over a 10-year period: A retrospective study

Objective

Full endoscopic lumbar discectomy (FELD) for lumbar disc herniation (LDH) has become popular in recent years. Previous studies have proven the efficacy, but few have discussed the possible risk factors of poor outcome. In this study, we reviewed patients who underwent FELD at Changhua Christian Hospital in the past 10 years and sought to identify factors associated with poor surgical outcomes and re-operations.

Methods

We retrospectively reviewed records from mid-2009 to mid-2018. Patients had undergone FELD and follow-up for ≥1 year were included. Factors included in the outcome evaluations were age, sex, surgical time, body mass index, surgical methods, disc herniation type, extension of herniation, degree of canal compromised, disc degenerative grade, smoking and alcohol use, surgical lumbar level, symptom duration, Oswestry low back disability index, and visual analog scale score. We had evolved from inside-out methods to outside-in methods after 2016, thus, we included this factor in the analysis. The primary outcomes of interest were poor/fair MacNab score and re-operation.

Results

From mid-2009 to mid-2018, 521 patients met our criteria and were analyzed. The median follow-up was 1685 days (range, 523–3923 days). Thirty-one (6.0%) patients had poor surgical outcomes (fair/poor MacNab score) and 45 (8.6%) patients required re-operation. Prolapsed herniated disc (P < 0.001), higher disc degenerative grade (P = 0.047), higher lumbar level (P = 0.026), longer preoperative symptoms (P < 0.001), and surgery before 2017 (outside-in technique, P = 0.020) were significant factors associated with poor outcomes in univariate analyses. In multivariate analyses, prolapsed herniated disc (P < 0.001), higher disc degenerative grade (P = 0.030), and higher lumbar level (P = 0.046) were statistically significant. The most common adverse symptom was numbness. Factors possibly associated with higher re-operation rate were older age (P = 0.045), alcohol use (P = 0.073) and higher lumbar level (P = 0.069). Only alcohol use showed statistically significant re-operation rates in multivariate analyses (P = 0.035).

Conclusions

For treating LDH by FELD, we concluded that prolapsed disc, higher disc degenerative grade, higher lumbar level, and longer preoperative symptom duration were possibly associated with unsatisfactory surgical outcomes (poor/fair MacNab score). The outside-in technique might be superior to the inside-out technique. Older age and alcohol use might be associated with a higher re-operation rate.

Patients with predominantly back pain at the time of lumbar fusion for low-grade spondylolisthesis experience similar clinical improvement to patients with predominantly leg pain: mid-term results

BACKGROUND CONTEXT

Patients with back pain predominance (BPP) have traditionally been thought to derive less predictable symptomatic relief from lumbar fusion surgery.

PURPOSE

To compare postoperative clinical outcomes as well as degree of improvement in clinical outcome measures between patients with BPP and patients with leg pain predominance (LPP) undergoing open posterior lumbar fusion.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Analysis of patients who underwent an open posterior lumbar fusion for low-grade (Meyerding Grade I or II) degenerative or isthmic spondylolisthesis from 2011 to 2018 was conducted. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, had less than 6 months of follow-up, presented with a lumbar vertebral body fracture, tumor, or infection, or underwent a fusion surgery that extended to the thoracic spine, high-grade spondylolisthesis, or concomitant deformity.

OUTCOME MEASURES

Radiographs obtained at preoperative, immediate postoperative, and final visits were evaluated for presence or absence of fusion. Patient-reported outcomes were recorded at preoperative and final clinic visits that included: visual analog scale (VAS) back/leg pain, and Oswestry disability index (ODI). Achievement of minimal clinically important difference (MCID) was analyzed, along with rates of postoperative complication and reoperation.

METHODS

Preoperative and final patient-reported outcomes were obtained. Achievement of MCID was evaluated using following thresholds: ODI 14.9, VAS-back pain 2.1, VAS-leg pain 2.8. For analysis, patients were divided into two groups based on predominant location of pain: predominantly VAS-back pain (BPP) and predominantly VAS-leg pain (LPP).

RESULTS

One hundred forty-one patients met inclusion criteria. Of these, 71 had LPP, and 70 had BPP. Patients with preoperative LPP experienced greater improvements in VAS-leg (p<.001) compared to those with BPP, whereas patients with preoperative BPP experienced greater improvements in VAS-back (p=.011) postoperatively compared to those with LPP. There were no differences in the final clinical outcomes. Additionally, LPP achieved MCID for VAS-leg (p=.027) at significantly higher proportion than BPP and BPP achieved MCID for VAS-back (p=.050) at significantly higher proportion than LPP.

CONCLUSIONS

Patients with low-grade spondylolisthesis who underwent an open posterior lumbar fusion had improvement in symptoms regardless of presentation with BPP or LPP. In properly indicated patients, posterior spinal fusion is effective for those with BPP in the setting of experiencing both leg and back pain, and clinicians can use this information for perioperative discussions and surgical decision-making.

The Duration of Symptoms Does Not Impact Clinical Outcomes Following Lumbar Decompression Surgery

STUDY DESIGN

A retrospective cohort analysis.

OBJECTIVE

The aim of this study was to assess whether duration of symptoms (DOS) has an effect on clinical outcomes in patients undergoing lumbar decompression.

SUMMARY OF BACKGROUND DATA

The success of surgical interventions for lumbar spinal stenosis varies depending on numerous factors, including DOS. However, existing literature does not provide a clear indication of the outcome of lumbar decompression surgery in regard to DOS secondary to nerve root compression.

METHODS

Analysis of patients who underwent primary lumbar laminectomy from 2008 through 2015 by one of two senior orthopedic spine surgeons was conducted. Exclusion criteria were as follows: previous lumbar surgery, patient under 18 years of age at time of surgery, or postoperative follow-up less than 3 months. Patients were divided into groups on the basis of preoperative DOS: less than 1 year and 1 year or greater. Patient-reported outcomes were obtained using Oswestry Disability Index (ODI) scores, Visual Analog Scales (VAS) scores for the back and leg, 12-Item Short Form Mental and Physical Survey (SF-12) scores, and Veterans Rand 12-Item Health Mental and Physical Survey (VR-12) scores. Patients were surveyed about expectations and postoperative satisfaction.

RESULTS

Two hundred ten patients were assessed; 108 with DOS of less than 1 year and 102 with DOS of 1 year or more. On multivariate analysis, patients with DOS of 1 year or greater presented with significantly lower SF-12 scores (P = 0.043). No significant differences existed in other outcome survey scores. Reoperation rates were not significantly different (P = 0.904). Both groups reported high levels of satisfaction (odds ratio 0.42, P = 0.483) and that surgery met or exceeded their expectations (odds ratio 1.00, P = 0.308).

CONCLUSION

Symptom chronicity did not significantly affect postoperative clinical outcomes, reoperation rates, or patient satisfaction. Nonoperative treatment of lumbar spinal stenosis is often successful but may delay operative intervention. However, results of this study suggest that the delay does not negatively impact surgical outcomes.

LEVEL OF EVIDENCE

3.

A retrospective study of epidural and intravenous steroids after percutaneous endoscopic lumbar discectomy for large lumbar disc herniation

OBJECTIVE

To assess the early curative effect of epidural or intravenous administration of steroids during a percutaneous endoscopic lumbar discectomy (PELD).

METHODS

28 consecutive patients who underwent PELD due to large lumbar disc herniation between November 2014 and January 2016 were followed up for 6 months. These patients were divided into two groups according to the treatment they received after PELD. 14 patients (Group A) were treated by PELD and epidural steroids, while the other 14 patients (Group B) were treated by PELD and intravenous steroids. We evaluated the effectiveness by the preoperative and postoperative visual analogue scale (VAS) scores for back and leg pain, and the postoperative Oswestry disability index (ODI) at 3 weeks after surgery via the clinical charts and telephone interview. Postoperative hospital stay and time return to work were investigated as well.

RESULTS

There is a significant decrease in VAS (back, leg), ODI, and time return to work (p < 0.05). For VAS (back), Group A showed a significant decrease compared with Group B at 1 day and 1 week after surgery (p = 0.011, p = 0.017). As for VAS (leg), Group A showed a significant decrease compared with Group B at 1 day, 1 week, 3 weeks, and 3 months follow-up examinations (p = 0.002, p = 0.006, p < 0.001, p < 0.001). For ODI, Group A showed a notable decrease compared with Group B (p < 0.001). The postoperative hospital stay in two groups was not statistically different (p = 0.636). But the time return to work in Group A was significantly shorter than that in Group B (p = 0.023).

CONCLUSION

Patients who underwent PELD with epidural steroid administration for large lumbar disc herniation showed favorable curative effect compared with those who underwent PELD with intravenous steroid administration.

Learning Curve of Percutaneous Endoscopic Lumbar Discectomy Based on the Period (Early vs. Late) and Technique (in-and-out vs. in-and-out-and-in): A Retrospective Comparative Study

Objective

To report the learning curve of percutaneous endoscopic lumbar discectomy (PELD) for a surgeon who had not been previously exposed to this procedure based on the period and detailed technique with a retrospective matched comparative design.

Methods

Of 213 patients with lumbar disc herniation encountered during the reference period, 35 patients who were followed up for 1 year after PELD were enrolled in this study. The patients were categorized by the period and technique of operation : group A, the first 15 cases, who underwent by the 'in-and-out' technique; group B, the next 20 cases, who underwent by the 'in-and-out-and-in' technique. The operation time, failure rate, blood loss, complication rate, re-herniation rate, the Visual Analogue Scale (VAS) for back and leg were checked. The alteration of dural sac cross-sectional area (DSCSA) between the preoperative and the postoperative MRI was checked.

Results

Operative time was rapidly reduced in the early phase, and then tapered to a steady state for the 35 cases receiving the PELD. After surgery, VAS scores for the back and leg were decreased significantly in both groups. Complications occurred in 2 patients in group A and 2 patients in group B. Between the two groups, there were significant differences in operative time, improvement of leg VAS, and expansion of DSCSA.

Conclusion

PELD learning curve seems to be acceptable with sufficient preparation. However, because of their high tendency to delayed operation time, operation failure, and re-herniation, caution should be exercised at the early phase of the procedure.

Lumbar Endoscopic Microdiscectomy: Where Are We Now? An Updated Literature Review Focused on Clinical Outcome, Complications, and Rate of Recurrence

Endoscopic disc surgery (EDS) for lumbar spine disc herniation is a well-known but developing field, which is increasingly spreading in the last few years. Rate of recurrence/residual, complications, and outcomes, in comparison with standard microdiscectomy (MD), is still debated and need further data. We performed an extensive review based on the last 6 years of surgical series, systematic reviews, and meta-analyses reported in international, English-written literature. Articles regarding patients treated through endoscopic transforaminal or interlaminar approaches for microdiscectomy (MD) were included in the present review. Papers focused on endoscopic surgery for other spinal diseases were not included. From July 2009 to July 2015, we identified 51 surgical series, 5 systematic reviews, and one meta-analysis reported. In lumbar EDS, rate of complications, length of hospital staying, return to daily activities, and overall patients' satisfaction seem comparable to standard MD. Rate of recurrence/residual seems higher in EDS, although data are nonhomogeneous among different series. Surgical indication and experience of the performing surgeon are crucial factors affecting the outcome. There is growing but still weak evidence that lumbar EDS is a valid and safe alternative to standard open microdiscectomy. Statistically reliable data obtained from randomized controlled trials (better if multicentric) are desirable to further confirm these results.