Learning curve of full-endoscopic technique through interlaminar approach for L5/S1 disk herniations

Outcome of Percutaneous Endoscopic Lumbar Discectomy in Relation to the Surgeon's Experience: Propensity Score Matching

Percutaneous endoscopic lumbar discectomy (PELD) presents a challenging learning curve, and the correlation between surgeon experience and clinical outcomes remains contentious. This retrospective study aimed to compare the outcomes of PELD performed by a single surgeon at beginner and experienced stages. Propensity score matching selected 150 patients (75 per group) with a minimum 3-year follow-up. Clinical and radiological outcomes, perioperative complications, and adverse events were assessed. Baseline characteristics, pain improvement, patient satisfaction, and radiological outcomes did not differ between the groups. However, operation time was longer in the beginner group than in the experienced group (57.5 min [IQR, 50.0-70.0] versus 50.0 min [IQR, 45.0-55.0], p < 0.001). The beginner group had higher perioperative complication rates (eight patients [10.7%] versus one patient [1.3%], with a hazard ratio of 8.836 [95% CI, 1.077-72.514], p = 0.034) and lower 3-year survival without adverse events (19 patients [25.3%] in the beginner group and 10 patients [13.3%] in the experienced group, p = 0.045). Our findings indicate that the clinical outcomes were more favorable in patients operated on at the experienced stage compared to those treated at the beginner stage.

Validation of an endoscopic flavectomy training model

OBJECTIVE

to validate a lumbar spine endoscopic flavectomy simulator using the construct method and to assess the acceptability of the simulator in medical education.

METHODS

thirty medical students and ten video-assisted surgery experienced orthopedists performed an endoscopic flavectomy procedure in the simulator. Time, look-downs, lost instruments, respect for the stipulated edge of the ligamentum flavum, regularity of the incision, GOALS checklist (Global Operative Assessment of Laparoscopic Skills), and responses to the Likert Scale adapted for this study were analyzed.

RESULTS

all variables differed between groups. Procedure time was shorter in the physician group (p < 0.001). Look-downs and instrument losses were seven times greater among students than physicians. Half of the students respected the designated incision limits, compared to 80% of the physicians. In the student group, about 30% of the incisions were regular, compared to 100% in the physician group (p < 0.001). The physicians performed better in all GOALS checklist domains. All the physicians and more than 96% of the students considered the activity enjoyable, and approximately 90% believed that the model was realistic and could contribute to medical education.

CONCLUSIONS

the simulator could differentiate the groups' experience level, indicating construct validity, and both groups reported high acceptability.

Learning Curve for Interlaminar Endoscopic Lumbar Discectomy: A Systematic Review

BACKGROUND

Interlaminar endoscopic lumbar discectomy (IELD) is an efficient surgical treatment for lumbar disc herniation. However, this minimally invasive procedure requires a considerable learning curve that has not yet been standardized. This review aimed to evaluate the learning curve's characteristics, including the cutoff point required to achieve technical proficiency and to discuss appropriate training methods.

METHODS

We systematically searched the core databases (PubMed, Embase, and Cochrane Library) for clinical studies that evaluated the learning curve using quantitative data. We performed a quality assessment using the Newcastle-Ottawa scale. We also compared descriptive statistics, including operative time and other variables before and after the cutoff point.

RESULTS

Six studies reporting 302 cases of IELD were selected from 7188 screened articles. The cutoff point was randomly set in 3 studies and determined as the curve's asymptote in 3 studies. The mean value for the cutoff point was 22.17 ± 12.40 cases (range: 10-43 cases) and mainly determined based on the operative time, which was shorter in the late group than that in the early group (P < 0.05). The cutoff points were not significant for patient outcome parameters such as pain score, functional result, surgical failure, or complications.

CONCLUSIONS

The evidence of published studies regarding the learning curve for the IELD technique is insufficient. The reported cutoff points may be significant only for task efficiency. Moreover, they may not represent the asymptote of the curve. Future studies should evaluate the actual plateau points using patient outcome data.

Comparison of the Minimally Invasive Tubular Transmuscular Approach with the Conventional Microsurgical Approach for Microsurgical Treatment of Lumbar Disk Herniation: A Prospective Randomized Study

BACKGROUND

 The aim of this study is to compare the outcome of the minimally invasive transmuscular approach using a tubular retractor system (Metrx) with the conventional microsurgical standard approach (CM) for microsurgical treatment of lumbar disk herniation.

METHODS

 This is a prospective randomized controlled study with a 1:1 distribution of patients in CM and Metrx study groups. Two hundred and twenty-seven (117 CM and 110 Metrx) patients were included. The primary outcome parameters are postoperative pain intensity reduction, length of hospitalization, postoperative quality of life, and daily life performance based on the standardized questionnaires: Visual Analog Scale (VAS), 36-Item Short Form Survey (SF-36), Oswestry Disability Index (ODI), and Prolo scores. The secondary outcome parameters are intraoperative variables: surgery duration, blood loss, and fluoroscopy dose.

RESULTS

 There were no significant statistical differences in the primary outcome measures between the two groups with respect to postoperative pain relief (median VAS pre-op to 3 months post-op for sciatica: 9-2 [CM] vs. 8-2 [Metrx]; for lumbago: 7-2.5 [CM] vs. 6-3 [Metrx]), the length of hospitalization (median of 5 days), or the frequency of occupational reintegration after 3 months (59.1 vs. 60.7%).

CONCLUSION

 The microsurgical therapy of lumbar disk herniation via a Metrx approach is a safe and effective treatment option and is equivalent to the CM approach.

Endoscopic interlaminar lumbar discectomy: How to decrease the learning curve

Background:

Herniated lumbar disc is a common cause of lumbosacral pain. Endoscopic interlaminar lumbar discectomy (ILD) is a well-established technique that provided comparable results to micro-discectomy. The aim of the study is to describe the learning curve of endoscopic ILD and explore measures that could improve effectiveness and decrease blood loss and operative time with accumulation of reasonable experience.

Methods:

This retrospective cohort study included 65 patients presenting with symptomatic herniated lumbar disc who underwent endoscopic ILD. Patients were divided into two groups: Group I (standard technique) and Group II (modified technique). Collected data included patients’ age, gender, preoperative manifestations, visual analog score (VAS) for pain, Oswestry Disability Index (ODI), disc level, operative time, intraoperative blood loss, complications, and follow-up data at 1, 6, and 12 months postoperatively. Primary outcomes included total operative time, amount of intraoperative blood loss, and post-operative improvement in pain. Secondary outcomes included intraoperative complications, rate of conversion to open surgery, and recurrence.

Results:

Post-operative VAS and ODI improved significantly in both groups. Mean total surgical time and intraoperative blood loss were significantly lower in Group II compared to Group I (P < 0.001). The learning curves for operative time and intraoperative blood loss were shallow in Group I, and almost flattened in Group II. Complications were recorded in only three cases, and no symptomatic recurrences were reported.

Conclusion:

The learning curve of endoscopic ILD was shallow with standard technique, indicating difficulties in mastering the procedure. The proposed modified technique helped reaching the required level of proficiency in the early phase of the curve, providing a significant reduction in operative time and blood loss, with comparable effectiveness and safety as the standard technique.

Feasibility of Using Intraoperative Neuromonitoring in the Prophylaxis of Dysesthesia in Transforaminal Endoscopic Discectomies of the Lumbar Spine

(1) Background: Postoperative nerve root injury with dysesthesia is the most frequent sequela following lumbar endoscopic transforaminal discectomy. At times, it may be accompanied by transient and rarely by permanent motor weakness. The authors hypothesized that direct compression of the exiting nerve root and its dorsal root ganglion (DRG) by manipulating the working cannula or endoscopic instruments may play a role. (2) Objective: To assess whether intraoperative neurophysiological monitoring can help prevent nerve root injury by identifying neurophysiological events during the initial placement of the endoscopic working cannula and the directly visualized video endoscopic procedure. (3) Methods: The authors performed a retrospective chart review of 65 (35 female and 30 male) patients who underwent transforaminal endoscopic decompression for failed non-operative treatment of lumbar disc herniation from 2012 to 2020. The patients’ age ranged from 22 to 86 years, with an average of 51.75 years. Patients in the experimental group (32 patients) had intraoperative neurophysiological monitoring recordings using sensory evoked (SSEP), and transcranial motor evoked potentials (TCEP), those in the control group (32 patients) did not. The SSEP and TCMEP data were analyzed and correlated to the postoperative course, including dysesthesia and clinical outcomes using modified Macnab criteria, Oswestry disability index (ODI), visual analog scale (VAS) for leg and back pain. (4) Results: The surgical levels were L4/L5 in 44.6%, L5/S1 in 23.1%, and L3/L4 in 9.2%. Of the 65 patients, 56.9% (37/65) had surgery on the left, 36.9% (24/65) on the right, and the remaining 6.2% (4/65) underwent bilateral decompression. Postoperative dysesthesia occurred in 2 patients in the experimental and six patients in the control group. In the experimental neuromonitoring group, there was electrodiagnostic evidence of compression of the exiting nerve root’s DRG in 24 (72.7%) of the 32 patients after initial transforaminal placement of the working cannula. A 5% or more decrease and a 50% or more decrease in amplitude of SSEPs and TCEPs recordings of the exiting nerve root were resolved by repositioning the working cannula or by pausing the root manipulation until recovery to baseline, which typically occurred within an average of 1.15 min. In 15 of the 24 patients with such latency and amplitude changes, a foraminoplasty was performed before advancing the endoscopic working cannula via the transforaminal approach into the neuroforamen to avoid an impeding nerve root injury and postoperative dysesthesia. (5) Conclusion: Neuromonitoring enabled the intraoperative diagnosis of DRG compression during the initial transforaminal placement of the endoscopic working cannula. Future studies with more statistical power will have to investigate whether employing neuromonitoring to avoid intraoperative compression of the exiting nerve root is predictive of lower postoperative dysesthesia rates in patients undergoing videoendoscopic transforaminal discectomy.

Estimation and influence of blood loss under endoscope for percutaneous endoscopic lumbar discectomy (PELD): a clinical observational study combined with in vitro experiment

PURPOSE

The purpose of this study is to come up with new methods to quantitate the blood loss under endoscope and explore the influence of blood loss on percutaneous endoscopic lumbar discectomy (PELD).

METHODS

Clinical research and in vitro experiment are combined. In the in vitro experiment, 2.0-ml blood was diluted in different ratio to simulate the rinse solution of PELD, the hematocrit method (HCT-M) and red blood cell count method (RBC-M) were came up to estimate blood loss and the new methods were calibrated with the direct measurement method (Direct-M). In clinical research, 74 patients with L5/S1 disk herniation were treated with PELD, and HCT-M and the empirical method (EMP-M) were used to estimate the blood loss under endoscope. According to blood loss, all patients were divided into group A (≤ 10 ml) and group B (> 10 ml). The blood loss, operation time, fluoroscopy frequency, visual analog scale (VAS), and Oswestry Disability Index (ODI) scores were compared between the two groups.

RESULTS

In the in vitro experiment, the hematocrit of the rinse solution was always stable over time. The estimated blood loss by HCT-M was stable and quite approximate to actual blood volume (2.0 ml) whatever the blood dilution ratio, while according to RBC-M, the estimated blood loss was close to the actual blood volume only when the dilution ratio was greater than 300 times. In clinical research, the blood loss estimated by HCT-M was higher than that by EMP-M in both groups (P < 0.05). There was a significant difference between group A and group B in blood loss (7.40 ± 1.61 vs 19.91 ± 10.94 ml), operation time (80.51 ± 34.70 vs 136.51 ± 41.88 min), and fluoroscopy frequency (6.92 ± 1.52 vs 11.11 ± 2.32 times) (P < 0.05). The VAS and ODI scores in group B were higher than that in group A 1 week after operation (P < 0.05); however, the scores were not different between the two groups at pre-operation (P > 0.05).

CONCLUSION

HCT-M is a reliable method to estimate endoscopic blood loss in PELD. The amount of endoscopic blood loss affects the operative procedure in operation time and fluoroscopy frequency, as well as clinical effects in VAS and ODI scores after operation in short term.

Scientific View on Endoscopic Spine Surgery: Can Spinal Endoscopy Become a Mainstream Surgical Tool?

With the health care environment becoming increasingly patient centric and cost-conscious, interest levels in spinal endoscopy are at an all-time high. Patient demand for the least invasive procedures combined with surgeon desire to maximally shorten the postoperative recovery period has further driven this surgical evolution. Mounting scientific evidence demonstrates the noninferiority and perhaps even superiority of endoscopic techniques to more conventional spinal surgery for the treatment of spinal stenosis and disc herniations. Although higher level evidence is much needed to support the clinical utility of the latest endoscopic techniques and surgical indications, it appears that the entrance of spinal endoscopy into the mainstream arena of spinal surgery is inevitable.

A History of Endoscopic Lumbar Spine Surgery: What Have We Learnt?

The new development and finally the general acceptance of surgical techniques among the worldwide surgical community sometimes create fascinating stories. This is also true for the history of endoscopic lumbar spine surgery. In the last 100 years there was a “natural” evolution of surgical techniques with continuous improvement and “refinement” of lumbar decompression techniques towards less invasive operations with the final “endpoint” of microsurgery. However the application of percutaneous, image-guided, and endoscopic technologies has revolutionized minimally invasive surgery. This article describes the history of endoscopic lumbar spine surgery and its major milestones and protagonists which have helped to make endoscopic lumbar spine surgery “disruptive” minimally invasive surgical technology which has changed the world of lumbar decompression surgery.

“The past is the mother of the future”

Henri Cartier Bresson, French Photographer, 1908-2004

Full-endoscopic discectomy via the interlaminar approach for disc herniation at L4-L5 and L5-S1: An observational study

The purpose of this retrospective study was to investigate the clinical outcomes of full-endoscopic discectomy via the interlaminar approach in the treatment of lumbar disc herniation (LDH) at L4-L5 under general anesthesia.Eighty-four patients who underwent full-endoscopic discectomy via the interlaminar approach at L4-L5 or L5-S1 were included. Durations of surgery, intraoperative radiation, postoperative bedrest, and hospitalization as well as perioperative complications were recorded. The visual analog scale (VAS) score for leg and back pain and the Oswestry disability index (ODI) score were evaluated preoperatively and at 3, 6, and 12 months postoperatively.The mean durations of surgeries in surgeries involving L4-L5 and L5-S1 were 69.8 ± 18.8 and 67.0 ± 20.1 minutes, respectively. The mean durations of intraoperative radiation were 1.2 ± 0.3 and 1.3 ± 0.3 seconds, respectively. The mean VAS and ODI scores improved significantly postoperatively compared with the preoperative scores. The perioperative complications included intraoperative epineurium injury in 3 cases without nerve injury, cerebrospinal fluid leakage, or cauda equina syndrome. The total recurrence rate after 12 months follow-up was 1.2% (one case at L5-S1).Full-endoscopic discectomy via the interlaminar approach could be considered as one of the alternative options for the treatment of LDH at L4-L5.

ENDOSCOPIC INTERLAMINAR DISCECTOMY. USE OF SWINE CADAVERS AS A TRAINING MODEL

ABSTRACT Objective: To analyze the possibility of using cadavers of pigs for training in endoscopic interlaminar discectomy. Methods: Five young pigs were used. The necessary instruments and equipment were used, and the endoscopic transforaminal and interlaminar percutaneous approach was performed at the L7-S1 level. A specialist surgeon performed the procedure. The points of entry, needle angulation, and subjective technical difficulties indicated by the surgeon were analyzed. Results: The mean weight of pigs was 42.2 kg. The posterolateral (transforaminal) entry point was, on average, 6.28 cm from the midline at an angulation of 32.8°. The posterior (interlaminar) entry point was on average 1.82 cm. Full-endoscopic interlaminar discectomy was possible in all animals of the sample. The structures described in the literature were visible endoscopically in 100% of the models. Conclusions: The demonstrated benefits and increased indications of endoscopic lumbar surgery created the need to establish safer and more efficient training processes. The authors raise the possibility of using experimental models to develop technical skills in endoscopy via interlaminar approach. The use of teaching tools such as animal models constitutes a new learning technique and give more confidence to surgeons. The use of cadavers of pigs, obtained according to ethics, avoids the use of human cadavers, and minimizes the development of the learning curve on patients.

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.