Percutaneous endoscopic approach for highly migrated intracanal disc herniations by foraminoplastic technique using rigid working channel endoscope

Bibliometric and Visualization Analysis of Research Hotspots and Frontiers in Endoscopic Lumbar Discectomy

Background

The increasing utilization of endoscopic lumbar discectomy (ELD) in spinal surgery has sparked widespread interest and research. This study utilizes bibliometric analysis to identify current research trends and advancements in this innovative surgical technique, with the goal of informing and improving surgical practices.

Methods

We retrieved relevant literature on ELD from the Science Citation Index Expanded (SCI-Expanded) within the Web of Science Core Collection (WoSCC) database as research samples. Various visualization tools, such as VOSviewer, CiteSpace, Scimago Graphica, Pajek, and online bibliometric platform, were employed to generate scientific knowledge maps for the purpose of visual presentation and data analysis.

Results

Over the past two decades, there has been significant progress in the research related to ELD, particularly since 2016. China has emerged as the most productive country, while South Korea and the United States have exerted greater academic influence. Tongji University has contributed the highest number of research output, while academic achievements published by Wooridul Spine Hospital are highly esteemed by scholars. Lee SH and Ruetten S are the most prolific author and the most highly cited author, respectively. World Neurosurg has published the highest number of publications, while Spine has become the most influential journal. Clinical Neurology and Surgery are the primary subject categories. Research in this field primarily revolves around improving ELD techniques, evaluating postoperative efficacy and prognosis prediction, studying complications and risk factors, as well as comparative research with other surgical techniques. Keywords such as risk factors, LDH, PETD, lumbar spinal stenosis, degeneration, recurrent herniation, laminectomy, local anesthesia, and foraminoplasty highlight the current research hotspots and future cutting-edge trends.

Conclusion

This study employed bibliometric analysis to elucidate the research hotspots and frontiers in ELD. The findings have significant implications for advancing research and development in this field.

Endoscopic Treatment of Lumbar Degenerative Disc Disease: A Narrative Review of Full-Endoscopic and Unilateral Biportal Endoscopic Spine Surgery

BACKGROUND

Degenerative lumbar spine disease is the leading cause of disability and work absenteeism worldwide. Lumbar microdiscectomy became the standard treatment for herniated discs and stenotic disease. With the evolution of different techniques, endoscopic spinal surgery emerged to minimize the surgical footprint while providing at least non-inferior results. Currently, two different types of endoscopic spine procedures are dominating the surgical scenario: "Full-Endoscopic" (FE) and Unilateral Biportal Endoscopic" (UBE) Spine Surgery. The aim of this study is to describe and analyze their indications, their technical characteristicswithitsadvantagesanddisadvantagesofbothtechniquesandtheirfuture trends.

METHODS

We performed a narrative review of the most relevant articles published up to August 2023 through a Pub Med search. The search terms " FE Spine Surgery" and " UBE Spine Surgery" were used. The articles selected, were independently reviewed by 3 authors and 55 full text articles were reviewed.

RESULTS

The FE and UBE Spine Surgery techniques were described. The FE technique is performed with a monoportal access under constant saline irrigation. The FE comprises the transforaminal and the interlaminar approaches, and the indication depends from the pathology to treat, and still remains controversial. UBE can approach also the spine from a posterior, postero lateral,and para spinal route. It uses two different ports addressed to a target with continuous irrigation. The process of establishing these two portals is called triangulation.

CONCLUSIONS

FE and UBE spine surgery have demonstrated outcomes comparable to open surgery, minimizing complications and surgical footprint.

Clinical Outcomes Following Decompression of Central Canal and Lateral Recess Simultaneous Stenosis, with a Focus on Multilevel Stenosis: A Randomized Comparison of Microscopic Bilateral Laminotomy versus Total Laminectomy with Posterior Spinal Fusion

BACKGROUND

In patients with simultaneous lumbar central spinal stenosis (LCSS) and lateral recess stenosis (LRS) at multiple levels, spinal decompression using microscopic bilateral laminotomy was compared to total laminectomy plus medial facetectomy and fusion (LF).

METHODS

From 2017 to 2022, this trial was performed to examine 96 patients with concomitant LCS and LRS at multilevel. Of the 96 patients, 48 were allocated to the following groups: LF (group I) or microscopic bilateral laminotomy (group II). However, 76 patients completed the study. We compared the outcomes in these 2 groups.

RESULTS

Microscopic bilateral laminotomy was superior in most outcome measures. Delta-visual analog scale leg pain in group II was significantly greater than in group I (mean-group I: 4.368 vs. group II: 5.368, P value = 0.001). Complication and revision rates were lower in the microscopic bilateral laminotomy than in group I, except for incidental durotomy occurrence (group II: 31.58% -group I: 7.89%, P value = 0.0190). The rate of revision surgery for group I compared with group II was 44.74% versus 13.16% (P value = 0.0047), indicating the superiority of laminotomy over LF. The mean length of hospital stay was 3.551 ± 0.6349 in group II versus 6.774 ± 1.197 in group I (P value <0.0001). Also, blood loss during surgery was significantly lower in group II (P value <0.0001).

CONCLUSIONS

The findings indicate that microscopic bilateral laminotomy provides favorable clinical and radiological outcomes for individuals experiencing multilevel lumbar central canal and LRS. However, a higher frequency of durotomy may occur during microsurgical procedures.

Transforaminal endoscopic lumbar discectomy with two-segment foraminoplasty for the treatment of very highly migrated lumbar disc herniation: a retrospective analysis

BACKGROUND

The surgical resection of very highly migrated lumbar disc herniation (VHM-LDH) is technically challenging owing to the absence of technical guidelines. Hence, in the present study, we introduced the transforaminal endoscopic lumbar discectomy (TELD) with two-segment foraminoplasty to manage VHM-LDH and evaluated its radiographic and midterm clinical outcomes.

MATERIALS AND METHODS

The present study is a retrospective analysis of 33 consecutive patients with VHM-LDH who underwent TELD with two-segment foraminoplasty. The foraminoplasty was performed on two adjacent vertebrae on the basis of the migration direction of disc fragments to fully expose the disc fragments and completely decompress the impinged nerve root. The operation duration, blood loss, intra- and postoperative complications, and recurrences were recorded. Additionally, imageological observations were evaluated immediately after the procedure via magnetic resonance image and computerized tomography. Clinical outcomes were evaluated by calculating the visual analog scale (VAS) score and Oswestry Disability Index (ODI). The MacNab criterion was reviewed to assess the patients' opinions on treatment satisfaction. The resection rate of bony structures were quantitatively evaluated on postoperative image. The segmental stability was radiologically evaluated at least a year after the surgery. Additionally, surgery-related and postoperative complications were evaluated.

RESULTS

The average age of the patients was 56.87 ± 7.77 years, with a mean follow-up of 20.95 ± 2.09 months. The pain was relieved in all patients immediately after the surgery. The VAS score and ODI decreased significantly at each postoperative follow-up compared with those observed before the surgery (P < 0.05). The mean operation duration, blood loss, and hospital stay were 56.17 ± 16.21 min, 10.57 ± 6.92 mL, and 3.12 ± 1.23 days, respectively. No residual disc fragments, iatrogenic pedicle fractures, and segmental instability were observed in the postoperative images. For both up- and down- migrated herniation in the upper lumbar region, the upper limit value of resection percentage for the cranial SAP, caudal SAP, and pedicle was 33%, 30%, and 34%, respectively; while those in the lower lumbar region was 42%, 36%, and 46%, respectively. At the last follow-up, the satisfaction rate of the patients regarding the surgery was 97%. Surgery-related complications including dural tear, nerve root injury, epidural hematoma, iatrogenic pedicle fractures, and segmental instability were not observed. One patient (3%) suffered from the recurrence of LDH 10 months after the initial surgery and underwent revision surgery.

CONCLUSIONS

The TELD with two-segment foraminoplasty is safe and effective for VHM-LDH management. Proper patient selection and efficient endoscopic skills are required for applying this technique to obtain satisfactory outcomes.

Transforaminal Full-Endoscopic Ventral Facetectomy: Midterm Results and Factors Associated with Poor Surgical Outcomes

BACKGROUND

 Full-endoscopic spine surgery (FESS) is a well-established procedure for herniated nucleus pulposus. It is a minimally invasive surgery that can be performed under local anesthesia through only an 8-mm skin incision. With improvements in surgical equipment such as high-speed drills, the indications for FESS have expanded to include lumbar spinal stenosis (LSS). We perform a transforaminal full-endoscopic ventral facetectomy (TF-FEVF) for unilateral nerve root-type lateral recess stenosis (LRS) using a transforaminal approach under local anesthesia.The aim of this study was to examine the postoperative results of TF-FEVF for LRS and to identify factors associated with poor surgical outcomes. 85 patients who underwent TF-FEVF for LRS under local anesthesia. Clinical outcomes were determined by visual analog scale (VAS) and the modified MacNab criteria. Evaluation was performed using magnetic resonance imaging (MRI), computed tomography (CT), and flexion-extension radiographs.

METHODS

 This study involved 85 patients (47 males and 38 females) who underwent TF-FEVF for LRS. The mean age was 70.5 years and the mean follow-up duration was 14.8 months. Data were collected on sex, age, level of operation, diagnosis, history of spine surgery at the same level, and duration of follow-up. The diagnosis was categorized as LSS with or without disk bulging. Clinical evaluation was performed using the VAS and modified MacNab criteria. MRI was used to evaluate the degree of disk degeneration, vertebral endplate degeneration, disk height, thickening of the ligamentum flavum, and stenosis. Bony stenosis was evaluated using CT. Sagittal translation and sagittal angulation were also measured by flexion-extension radiographs, and the Cobb angle was measured using a standing front view radiograph. All variables were compared between patients with excellent/good outcomes (E/G group) and those with fair/poor outcomes (F/P group) using the modified MacNab criteria.

RESULTS

 Postoperative VAS showed that leg pain decreased from 59.0 ± 28.6 preoperatively to 17.9 ± 27.2 at the final follow-up (p < 0.01) and that lower back pain also decreased from 60.7 ± 26.6 preoperatively to 27.3 ± 28.6 at final follow-up (p < 0.01). According to the modified MacNab criteria, the results during the final follow-up were excellent in 39 cases, good in 21 cases, fair in 13 cases, and poor in 12 cases. There were no significant differences in sex, age, diagnosis, history of spine surgery, and duration of follow-up periods between the 60 cases (70.6%) in the E/G group and the 25 cases (29.4%) in the F/P group. Imaging evaluation revealed statistically significant differences between the E/G group and the F/P group in intervertebral angle flexion (3.2 vs. 0.4 degrees; p < 0.05), sagittal angulation (4.3 vs. 8.1 degrees; p < 0.05), slip in flexion (0.9 vs. 2.8 mm; p < 0.05), sagittal translation (0.7 vs. 1.6 mm; p < 0.05), and Cobb angle (-0.5 vs. -1.9 degrees; p < 0.05).

CONCLUSION

 Midterm results of TF-FEVF were generally favorable; factors contributing to good or poor TF-FEVF outcomes were large sagittal angulation, large sagittal translation, and concave side.

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.

Transforaminal Contrast Injection Before Computed Tomography-Guided Lateral Endoscopic Lumbar Diskectomy Improves Visualization of Exiting Nerve Root

BACKGROUND AND OBJECTIVES

Percutaneous endoscopic lumbar diskectomy (PELD) is an effective, minimally invasive method for removal of lateral lumbar disk herniations. This minimally invasive technique can be applied with high success and lead to faster recovery than traditional methods. Unfortunately, adoption of these techniques in the United States has been slow. A significant barrier to using this technique is often an inability to completely visualize relevant anatomy and increased operative times. In this article, we describe a technique using computed tomography (CT) guidance in conjunction with a neurogram to perform a PELD. We detail the steps in the technique and its advantages to the surgeon performing it.

METHODS

After a patient is placed supine on a table, a transforaminal injection of contrast is performed under fluoroscopic guidance. Then, after sterilizing and draping in a normal fashion, an intraoperative CT scan is taken with a reference frame in place. During the procedure, this allows for the CT guidance to have the exiting nerve root clearly outlined.

RESULTS

This procedure was successfully performed in a single patient, allowing greater visualization of the exiting nerve root during a difficult revision PELD case. No complications were experienced.

CONCLUSION

A novel technique using a neurogram with CT guidance during a PELD was used to assist with identification of anatomy and decompression of the exiting nerve root. This technique was used without complications.

Foraminoplasty Performed with a Trephine and a New Tool in Transforaminal Endoscopic Lumbar Discectomy: A Single-Center Retrospective Study

OBJECTIVE

Foraminoplasty is an important step in transforaminal endoscopic lumbar discectomy (TELD). A trephine is widely used in foraminoplasty. However, foraminoplasty using a trephine alone sometimes fails to remove the resected bone, resulting in the bone remaining in the foramen or spinal canal, which can potentially cause neurological irritation or injury. The objective of this study is to introduce a self-designed tool, referred to as an anchoring drill, for use with a trephine in foraminoplasty in TELD and to evaluate its advantages.

METHODS

A retrospective review was performed to identify patients who underwent L4-5 TELD between January 2019 to January 2022. Foraminoplasty was performed in all patients. Depending on whether the anchoring drill was used or not, patients were divided into two groups. Surgery-related parameters and complications were reviewed. Visual analog scale (VAS) and Japanese Orthopaedic Association (JOA) scores were also assessed for all patients. SPSS statistical software was used for statistical calculation.

RESULTS

A total of 100 patients were included (55 in the anchoring drill group and 45 in the trephine group). The incidence of residual bone fragments after foraminoplasty of the anchoring drill group was 9.09%, which was lower than that of the trephine group, at 33.33% (p < 0.05). The mean endoscopic operation time of the anchoring drill group was shorter than that of the trephine group (p < 0.05). The mean fluoroscopy time and duration of foraminoplasty showed no significant differences between the two cohorts. The total perioperative complication incidence was lower in the anchoring drill group, in which the neural irritation incidence showed a significant difference (anchoring drill group: 3.64%, trephine group: 17.78%, p < 0.05). VAS and JOA scores were significantly improved after the operation for all patients (p < 0.001), however, no statistical differences were found between the two groups at each follow-up visit.

CONCLUSION

The combination of a trephine with an anchor drill was demonstrated to be safe and effective in foraminoplasty in TELD, improving the success rate of foraminoplasty and reducing neurological complications compared to using trephine alone.

Transforaminal endoscopic lumbar discectomy using a 45° puncture angle and foraminotomy versus traditional THESYS for L5/S1 lumbar disc herniation: a prospective randomized controlled trial

PURPOSE

Prospective comparison of the efficacy and safety of transforaminal endoscopic lumbar discectomy (TELD) with a 45° puncture angle versus traditional Thomas Hoogland endoscopy spine systems (THESYS) for the surgical treatment of L5/S1 lumbar disc herniation (LDH).

METHODS

Consecutive patients with L5/S1 LDH who underwent TELD were randomized (1:1) assigned to the 45° TELD group and the THESYS group. Clinical outcomes were assessed at pre-operation, 1-day and 3/6-months post-operation till final follow-up. Surgical-related parameters, visual analogue scale (VAS) score, oswestry disability index (ODI), and modified MacNab criteria, and surgical complications were recorded and analysed.

RESULTS

All patients were followed up for at least 24 months. Compared to the THESYS group, the 45° TELD group had a shorter operative time (P < 0.001) and intraoperative radiation time (P < 0.001) and a smaller VAS score for back pain (P < 0.001) and leg pain intraoperatively (P < 0.001). The VAS and ODI in the 45° TELD group were significantly better than those in the THESYS group within 3 months postoperatively. However, from 3 months on, both groups showed comparable VAS and ODI. There was no significant difference between the two groups of modified MacNab criteria. There were two cases of residual disc and two cases of recurrence that required reoperation in the THESYS group.

CONCLUSION

For L5/S1 LDH, the 45° TELD technique was superior to traditional THESYS in terms of surgery-related parameters and faster improvement of VAS and ODI, with a lower complication rate.

Translaminar Full Endoscopic Technique with Tom Shidi Needles for Highly- and Dorsally-Migrated Lumbar Disc Herniations

BACKGROUND

Thirty years have passed since Kambin's first clinical series of lumbar disc herniations (LDH) treated by arthroscopic microdiscectomy. Despite several advances in this interim, sequestrated LDHs over the dorsal aspect of the dura, and high-grade up- or downward disc migration have been a relative limitation of the transforaminal endoscopic technique. The interlaminar window was the next step to deal with such highly migrated LDHs. Favorable outcomes were obtained in 70-90% of the patients in the long-term, but recurrence rates remained high (approximately 12%), and the approach could be limited by the size of the interlaminar window. Few relevant studies have addressed the role of translaminar full endoscopic technique for migrated LDHs. To describe an innovative modification of the translaminar full endoscopic approach with Tom Shidi needles.

METHODS

This technical modification is presented in a detailed fashion for treating these challenging LDHs and illustrated through a clinical case.

RESULTS

The patient underwent successful translaminar full endoscopic technique with complete pain resolution postoperatively. The postprocedural course was uneventful. A follow-up imaging showed no evidence of residual LDHs fragments.

CONCLUSIONS

Translaminar full endoscopic technique with Tom Shidi needles is a promising modification of the previously presented interlaminar and translaminar endoscopic routes in the treatment of migrated LDHs to fasten surgical procedures and increase the safety of spinal canal manipulation.

An algorithm for selection of full endoscopic approach for symptomatic nerve root decompression

Background Context

Both Transforaminal (TF) and Interlaminar (IL) endoscopic approaches are established techniques of decompression for lumbar compressive radiculopathy. In the absence of adequate literature, there is always some dilemma in selecting the approach for endoscopic decompression leading to long learning curves and high chances of inadequate decompression, iatrogenic instability, dural tear, or dysesthesia. Hence authors propose a new surgical nomenclature and algorithm for selection of endoscopic approach.

Methods

This retrospective study included 396 of 626 consecutive patients who met the inclusion criteria, who underwent either TF (n=302) or IL (n=202) full endoscopic spine surgery. MRI findings of every patient were classified as per FAPDIS (Facet angle, Anterior pathology, Posterior pathology, Dorsal, Inferior, and Superior migration) algorithm. Inter-observer variations were calculated. The targeted nomenclature was used to define the selection of endoscopic TF or IL approach for symptomatic nerve root decompression. All patients were followed up for preop and postop 6 months VAS and Oswestry Disability Index score for validation of FAPDIS algorithm.

Results

Median age: 46.8 years; Sides and levels operated 330 single-level ipsilateral, 54 multiple-level ipsilateral, 6 single-level bilateral, and 6 multiple-level bilateral. Interobserver agreement in the selection of TF approach was 0.873 and IL approach was 0.882. Interobserver variability was also calculated for each FAPDIS factor, selection of P3 and P4 pathology was the main reason for disagreement. All other FAPDIS factors show good to excellent correlation. The overall VAS score decreased from a preoperative value of 9 to 1 at 6 months follow-up (p-value < 0.001), and the overall Oswestry Disability Index score improved from 89 to 12 (p-value <.001).

Conclusions

The author's new FAPDIS surgical nomenclature and algorithm is a reliable tool for describing the symptomatic nerve root compression for the selection of endoscopic surgical approach to achieve adequate decompression of offending neural structure with minimum challenges to minimize perioperative complication rate.

1 Year-follow-up of transforaminal surgical approach in the management of migrated disc herniation: a cross-sectional study

Transforaminal percutaneous endoscopic lumbar discectomy (TPELD) recently confirms its superiority compared to typical open discectomy in the treatment of very high-grade migrated disk herniation. In Vietnam, this technique has been applied in recent years; however; lack of reports and evidence.

OBJECTIVES

In this study, the authors would like to share their surgical experience and report the initial results in their center, after successfully performing TPELD for very high-grade migrated disk herniation in 40 patients.

PATIENTS AND METHODS

Forty patients, who underwent TPELD to remove the nucleus of very high-grade migrated disk herniation, were enrolled in this study. The study was carried out from April 2019 to April 2021. Preoperative and postoperative MRI were compared to demonstrate the removed disk. Postoperative visual analog score, oswestry disability index, and modified Macnab criteria were obtained after 1 month, 6 months, and 1 year and were compared.

RESULTS

There were no major complications related directly to this technique. Seven patients were operated at L3-4, 28 patients at L4-5, and 5 patients at l5-S1. Mean visual analog score for leg pain improved from 7.36±0.64 preoperatively to 1.22±1.16 at 6 months postoperatively and 1.34±1.47 at 1 year postoperatively (P<0.01). The mean preoperative oswestry disability index improved from 67.1±8.79 preoperatively to 12.1±13.48 at 1 year postoperatively (P<0.01). Excellent or good global outcomes were obtained in 95%.

CONCLUSIONS

TPELD is a minimally invasive treatment with effective and safe results of very high-grade migrated disk herniation. Improvement of several pain scores can be observed in the 12-month follow-up after surgery.

One-hole split endoscope technique for migrated lumbar disc herniation: a single-centre, retrospective study of a novel technique

BACKGROUND

Lumbar disc herniation (LDH) is one of the most common diseases of the spine, and migrated LDH is a more serious type, associated with nerve root function injury or abnormality. Regarding the increasing surgery adoption of treating migrated LDH, we aimed to investigate the clinical efficacy and safety of discectomy with a novel technique-one-hole split endoscope (OSE) technique.

METHODS

This was a retrospective analysis of migrated LDH treated between December 2020 and September 2021. Hospitalization time, operative duration, intraoperative blood loss, number of fluoroscopy exposures, incision length, postoperative facet preservation rate, number of excellent-good cases, lower back and leg visual analogue score (VAS), Oswestry Disability Index (ODI) and surgical complications were compared between high-grade migration group (82 cases) and low-grade migration group (148 cases). The Macnab criteria was used to evaluate the clinical outcome. The Shapiro‒Wilk test was used to test measurement data, and the χ² test was used to test counting data.

RESULTS

There was no significant difference in hospitalization time, operative duration, intraoperative blood loss, number of fluoroscopy exposures, incision length or postoperative facet preservation rate between the two groups by independent sample t test or nonparametric test. At any time point, the lower back and leg VAS and ODI of the two groups were significantly improved compared to those before the operation, but there was no significant difference between the two groups at the same time point by two-way repeated measures ANOVA. There were two cases of postoperative nerve root stimulation symptoms in the high-grade migration group and three cases in the low-grade migration group. There was one patient reoperated in the high-grade migration group. There was no significant difference in number of excellent-good cases between the two groups. The overall excellent-good rate was 89.6%.

CONCLUSION

The OSE technique has the advantages of less trauma, faster recovery, complete removal of the nucleus pulposus and a satisfactory early clinical efficacy in the treatment of migrated LDH.

Awake transforaminal endoscopic lumbar discectomy in an ambulatory surgery center: early clinical outcomes and complications of 100 patients

PURPOSE

Transforaminal endoscopic discectomy has been found to have equivalent outcomes to traditional discectomy techniques. Controversy exists concerning whether this should be performed under general anesthetic with neuromonitoring or can be safely performed on awake patients without neuromonitoring. This study aimed to evaluate the safety and effectiveness of awake transforaminal endoscopic discectomy in an ambulatory setting.

METHODS

100 consecutive patients with lumbar disc herniations treated with transforaminal endoscopic discectomy by a single surgeon were enrolled in the study. All procedures were performed under conscious sedation with local anesthetic. Preoperative and postoperative visual analog scale (VAS) scores were recorded and compared. Time spent in recovery prior to discharge home and complications were also recorded.

RESULTS

Average VAS score improved from a mean of 6.85 to 0.74 (median 7 to 0) immediately postoperatively. The average time spent in Post Anesthesia Care Unit (PACU) prior to discharge was 56.7 min. Average VAS score at 2 weeks was 3.07 (median 2.5). Complication rates were commensurate with published results in the literature. The most common complication was radiculitis, which appears to be more likely with foraminal/extraforaminal herniations at a rate of 20.7%, versus 2.6% for central/paracentral herniations. There were no cases that required conversion to general anesthetic or transfer to a hospital and no permanent nerve injuries in this cohort.

CONCLUSIONS

Endoscopic discectomy can safely and successfully be performed in an ambulatory surgery center under conscious sedation and local anesthetic without neuromonitoring. This procedure leads to rapid recovery in the PACU and significantly improved VAS scores postoperatively.

LEVEL OF EVIDENCE

Level IV.

Full-Endoscopic Lumbar Discectomy Approach Selection: A Systematic Review and Proposed Algorithm

STUDY DESIGN

A systematic review of the literature to develop an algorithm formulated by key opinion leaders.

OBJECTIVE

This study aimed to analyze currently available data and propose a decision-making algorithm for full-endoscopic lumbar discectomy for treating lumbar disc herniation (LDH) to help surgeons choose the most appropriate approach [transforaminal endoscopic lumbar discectomy (TELD) or interlaminar endoscopic lumbar discectomy (IELD)] for patients.

SUMMARY OF BACKGROUND DATA

Full-endoscopic discectomy has gained popularity in recent decades. To our knowledge, an algorithm for choosing the proper surgical approach has never been proposed.

MATERIALS AND METHODS

A systematic review of the literature using PubMed and MeSH terms was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Patient samples included patients with LDH treated with full-endoscopic discectomy. The inclusion criteria were interventional research (randomized and nonrandomized trials) and observation research (cohort, case-control, case series). Exclusion criteria were case series and technical reports. The criteria used for selecting patients were grouped and analyzed. Then, an algorithm was generated based on these findings with support and reconfirmation from key expert opinions. Data on overall complications were collected. Outcome measures included zone of herniation, level of herniation, and approach (TELD or IELD).

RESULTS

In total, 474 articles met the initial screening criteria. The detailed analysis identified the 80 best-matching articles; after applying the inclusion and exclusion criteria, 53 articles remained for this review.

CONCLUSIONS

The proposed algorithm suggests a TELD for LDH located in the foraminal or extraforaminal zones at upper and lower levels and for central and subarticular discs at the upper levels considering the anatomic foraminal features and the craniocaudal pathology location. An IELD is preferred for LDH in the central or subarticular zones at L4/L5 and L5/S1, especially if a high iliac crest or high-grade migration is found.

Current Indications for Spinal Endoscopic Surgery and Potential for Future Expansion

Endoscopic spine surgery (ESS) has evolved as a safe, effective, and efficient alternative for minimally invasive spine surgery (MISS). The innovation of full-endoscopic systems makes definitive decompression surgery through different approaches feasible. The approach can be determined according to the location of the target lesion or the surgeon's preference. During the past 2 decades, ESS has expanded its indications from lumbar to cervical spines. Except for decompression, endoscopy-assisted fusion surgery is also developing. However, ESS is still evolving and has a steep learning curve. The revolution of technologies and ESS techniques will enable surgeons to treat various spinal diseases more practically. In recent years, the application of the computer-assisted navigation system and augmented reality have reformed imaging quality and interpretation. The endoscopic rhizotomy techniques have opened a new way for MISS of chronic low back pain. This review introduces the current indications of ESS and its potential future expansion.

Bibliometric analysis and description of research trends on transforaminal full-endoscopic approach on the spine for the last two-decades

OBJECTIVE

The study aims to assess the current development status of transforaminal full-endoscopic spine surgery (TFES) by exploring and analyzing the published literature to obtain an overview of this field and discover the evolution and emerging topics that are underrepresented.

METHODS

Using Bibliometrix, CiteSpace, and VOSviewer, we analyzed the bibliometric data selected from the Web of Science Core Collection between January 2002 and November 2022. The descriptive and evaluative analyses of authors, institutes, countries, journals, keywords, and references are compiled. The quantity of research productivity was measured by the number of publications that were published. A quality indicator was thought to be the number of citations. In the bibliometric analysis of authors, areas, institutes, and references, we calculated and ranked the research impact by various metrics, such as the h-index and m-index.

RESULTS

A total of 628 articles were identified in the field of TFES by the 18.73% annual growth rate of research on the subject from 2002 to 2022, constituting the documents are by 1961 authors affiliated with 661 institutions in 42 countries or regions and published in 117 journals. The USA (n = 0.20) has the highest international collaboration rate, South Korea has the highest H-index value (h = 33), and China is ranked as the most productive country (n = 348). Brown univ., Tongji univ., and Wooridul Spine represented the most productive institutes ranked by the number of publications. Wooridul Spine Hospital demonstrated the highest quality of paper publication. The Pain Physician had the highest h-index (n = 18), and the most cited journal with the earliest publication year in the area of FEDS is Spine (t = 1855).

CONCLUSION

The bibliometric study showed a growing trend of research on transforaminal full-endoscopic spine surgery over the past 20 years. It has shown a significant increase in the number of authors, institutions, and international collaborating countries. South Korea, the United States, and China dominate the related areas. A growing body of evidence has revealed that TFES has leapfrogged from its infancy stage and gradually entered a mature development stage.

Modified lumbar foraminoplasty using a power-aided reciprocating burr for percutaneous transforaminal endoscopic lumbar discectomy: A technical note and clinical report

Background

One of the main difficulties in a transforaminal endoscopic lumbar discectomy (TELD), and simultaneously the most critical step, is performing an effective and safe foraminoplasty, which is especially difficult for beginners. To make it safer and faster for beginners to perform, we have used a specially designed power-aided reciprocating burr for TELD and reported the technical details.

Methods

From Jan. 2019 to Nov. 2022, 432 patients with single-level, symptomatic L4/5 or L5/S1 disc herniation were treated with TELD using a novel power-aided reciprocating burr. The surgical procedure is described in detail. Magnetic resonance imaging (MRI) was performed the following day and 3 months after the operation. The learning curves of surgeons with different seniority levels are displayed. The Visual Analogue Scale (VAS) score and the Oswestry Disability Index (ODI) were used to measure low back pain, leg pain, and lumbar function. All patients were followed up for at least 1 year.

Results

All patients underwent endoscopic surgery successfully. Among the 432 patients, radicular outer membrane damage was observed in 6 cases, and 1 case had hernia of the nerve tract. Except for this patient with aggravation of postoperative numbness, the postoperative neurological symptoms of all patients were significantly improved. The mean VAS scores for low back pain and leg pain and ODI scores were significantly decreased 6 w post-operatively and were maintained until 12 months post-operatively compared to preoperative scores (P < 0.05). All three doctors involved in the study had substantial experience in traditional open spinal surgery. The more operations all three surgeons completed, the more time spent on intervertebral foraminoplasty decreased (P < 0.05). Among them, doctors without experience in TELD surgery became proficient in this technique after accumulating experience in 13 cases. There was no significant difference in foraminoplasty time among these three surgeons during the same growing period (P > 0.05).

Conclusions

Current clinical data demonstrated the safety and efficacy of modified TELD using a power-aided reciprocating burr for treating lumbar disc herniation (LDH) and showed that this technique significantly reduces the learning curve for beginners when performing foraminoplasty.

Minimally invasive trans-superior articular process percutaneous endoscopic lumbar discectomy with robot assistance

BACKGROUND

To compare the clinical outcomes of patients with lumbar disc herniation treated with robot-assisted percutaneous endoscopic lumbar discectomy (r-PELD) or conventional PELD under fluoroscopy guidance (f-PELD).

METHODS

Our study group included 55 patients, 22 in the r-PELD group and 33 in the f-PELD group. The following clinical and surgical outcomes were compared between the two groups: the visual analog scale for radiculopathy pain; Oswestry Disability Index; intraoperative volume of blood loss; frequency of fluoroscopy used during the procedure; and MacNab classification. The follow-up period was 6-8 months.

RESULTS

Compared with f-PELD, r-PELD was associated with a lower volume of intraoperative blood loss and frequency of fluoroscopy (p < 0.01). There were no differences in complications, MacNab classification, postoperative disability and leg pain, and duration of hospitalization between the two groups.

CONCLUSION

Based on our findings, r-PELD provides a safe and effective alternative to conventional PELD for the treatment of lumbar disc herniations, with the accuracy for placement of punctures lowering radiation exposure.

Comparing oblique lumbar interbody fusion with lateral screw fixation and percutaneous endoscopic transforaminal discectomy (OLIF-PETD) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for the treatment of lumbar disc herniation complicated with lumbar instability

OBJECTIVE

To evaluate the early clinical effect of oblique lumbar interbody fusion with lateral screw fixation and percutaneous endoscopic transforaminal discectomy (OLIF-PETD) in the treatment of lumbar disc herniation with lumbar instability.

METHODS

A total of 22 patients with lumbar disc herniation and lumbar instability from August 2017 to August 2019 were enrolled in this retrospective study. The general information, perioperative indicators and complications were recorded. The clinical outcomes and radiological outcomes were evaluated before the operation, seven days after the operation, and at the last follow-up. Vertebral fusion and degree of multifidus muscle injury were evaluated at the last follow-up.

RESULTS

In this study, OLIF + PETD showed shorter incision length compared to the MIS-TLIF (P < 0.001). In the two groups, the clinical outcomes and radiological outcomes were significantly improved compared with the preoperative (P < 0.001). At the seven days after the operation and the last follow-up, the VAS of OLIF + PETD group was lower than that of MIS-TLIF group (P < 0.05). OLIF + PETD could give superior outcome in restoring disc height (P < 0.001), but the fusion segment angle of OLIF + PETD group was larger compared to the MIS-TLIF group seven days after the operation and at the last follow-up (P < 0.05). In addition, the fusion rate was not significantly different between the two groups (P > 0.05), but OLIF + PETD could avoid the multifidus injury (P < 0.001).

CONCLUSION

Compared to MIS-TLIF, OLIF-PETD can achieve satisfactory decompression effects and fusion rates with less multifidus injury and postoperative low back pain, which may be an alternative choice for the treatment of lumbar disc herniation combined with lumbar instability.

Percutaneous endoscopic interlaminar discectomy via inner border of inferior pedicle approach for downmigrated disc herniation: a retrospective study

Objective

To evaluate the efficacy and feasibility of percutaneous endoscopic interlaminar discectomy (PEID) via the inner border of the inferior pedicle approach for downmigrated disc herniation.

Methods

Seventeen patients who had downmigrated disc herniation were included in this study from May 2020 to February 2021. After PEID via the inner border of the inferior pedicle approach, a retrospective study was conducted on all patients. Radiologic findings were investigated, and based on the level of migration seen on preoperative magnetic resonance imaging (MRI), participants were divided into two types (high-grade and low-grade migrations). Preoperative, 1st post-operative day, 3rd post-operative month, and the final follow-up visual analogue scale (VAS) assessments for back and leg pain and preoperative, 3rd post-operative month, and the final follow-up Oswestry disability index (ODI) evaluations were performed. The clinical effects at the final follow-up were assessed by the modified MacNab criterion.

Results

All patients successfully completed surgery. There were 10 males and 7 females in the group. These patients were 42 years old on average (range, 25–68 years). Four and 13 patients had downmigrated disc herniation with high-grade and low-grade, respectively, on MRI. The mean follow-up duration was 10.47 ± 1.84 months (range, 8–14 months). The mean VAS score for back and leg improved from 5.18 ± 0.81 preoperatively to 1.35 ± 0.49 at the final follow-up (P < 0.05) and 6.94 ± 0.66 preoperatively to 1.47 ± 0.51 at the final follow-up (P < 0.05), respectively. The mean ODI score improved from 48.00 ± 3.64 preoperatively to 18.71 ± 1.31 at the final follow-up (P < 0.05). According to the modified MacNab criterion, 15 patients (88.2%) obtained excellent, while the rest 2 patients (11.8%) reported good outcomes.

Conclusion

PEID via the inner border of the inferior pedicle approach could be a good alternative option for the treatment of downmigrated disc herniation.

[Unilateral biportal endoscopic discectomy for high-grade migrated lumbar disc herniation]

OBJECTIVE

To investigate the effectiveness of the unilateral biportal endoscopy (UBE) technique in the treatment of high-grade migrated lumbar disc herniation (LDH).

METHODS

Between January 2020 and February 2021, 23 cases of high-grade migrated LDH were treated with discectomy via UBE. There were 14 males and 9 females, with a mean age of 48.7 years (range, 32-76 years). All patients had low back and leg pain. The disease duration ranged from 2 months to 7 years (median, 13 months). Lesion segments were L _{3, 4} in 2 cases, L _{4, 5} in 15 cases, and L ₅, S ₁ in 6 cases. The operation time, intraoperative blood loss, the time when the patients started to move off the floor, and postoperative complications were recorded. The effectiveness was evaluated using the visual analogue scale (VAS) score, the modified Oswestry disability index (ODI), and the modified MacNab criteria.

RESULTS

All operations were completed successfully, and no complication such as dural tear, epidural hematoma, nerve injury, or vascular injury occurred. The operation time ranged from 53 to 96 minutes, with an average of 71.0 minutes. The intraoperative blood loss ranged from 32 to 56 mL, with an average of 39.3 mL. All patients were removed the drainage tube and wore a lumbar brace to move off the floor around 1 to 2 days after operation. All patients were followed up 3-12 months after operation, with an average of 5.7 months. The VAS scores of low back pain and leg pain and the modified ODI at all postoperative time points were lower than those before operation, and the differences were significant ( P<0.05). The differences were significant ( P<0.05) when comparing the above indexes between the time points after operation. At last follow-up, the effectiveness was evaluated according to the modified MacNab criteria, and 17 cases were excellent, 4 cases were good, and 2 cases were fair, with an excellent and good rate of 91.3%. There was no recurrence of LDH during follow-up.

CONCLUSION

Discectomy via UBE is an effective method for the treatment of high-grade migrated LDH because of its flexibility, clear view, and wide range of intraoperative exploration, which can effectively reduce the risk of residual nucleus pulposus after operation.

Impact of Body Weight, Height, and Obesity on Selection of Skin Entry Point for Transforaminal Endoscopic Lumbar Discectomy

Background Prospective evaluation of the effect of physical parameters like height, weight and abdominal girth on different skin entry points in transforaminal endoscopic lumbar discectomy (TELD) in lower lumbar discs.

Methods This prospective study involved 174 patients with unilateral radicular pain or discogenic back pain, central, paracentral disc herniations and lateral canal stenosis at the level from L3 to S1 radiologically confirmed by magnetic resonance imaging (MRI) and failed conservative trial for 6 weeks. All patients underwent measurements of height, weight, body mass index (BMI), and abdominal girth preoperatively. All the four possible entry points, i.e., 45 to 45, posterolateral (PL), tip of spinous process (TOSP), and dorsum of the facet joint, were marked and point midway between PL and TOSP (PL-TOSP) skin entry was used.

Results The change in the value, i.e., distance from midline of all the entry points with physical parameters like height, weight, BMI, and abdominal circumference was statistically significant. The visual analog scale score decreased from a preoperative value of 7.98 to 1.84 at 6 months follow-up. The Oswestry disability index score improved from 72.53 to 16.26.

Conclusion The entry point in TELD is not a fixed value as it varies with the physical parameters like weight and abdominal girth of the patient. PL-TOSP is a safe entry point for common pathologies like central, paracentral herniations and lateral canal stenosis in lower lumbar levels and can be predicted preoperatively by proposed formula.

Targeted fully endoscopic visualized laminar trepanning approach under local anaesthesia for resection of highly migrated lumbar disc herniation

PURPOSE

To introduce a new fully endoscopic visualized laminar trepanning approach with a periendoscopic trephine under local anesthesia for resection of highly migrated lumbar disc herniation (LDH) and report the clinical outcomes of one year follow-up.

METHODS

Twenty-one patients with highly migrated LDH who underwent percutaneous endoscopic lumbar discectomy via the laminar trepanning approach from June 2019 to August 2020 were retrospectively reviewed. Patient-Reported Outcomes Measurement Information System (PROMIS) Short Forms-Pain Interference (PI) and Physical Function (PF) were selected as outcome measures. The operating duration and complication were documented.

RESULTS

The average age of the 21 patients (15 males, 6 females) was 37.8 ± 6.0 years (29-52 years). Disc migration originated from L4/5 in 19 patients, L5/S1 in two patients. The mean operative duration was 54.1 ± 9.0 minutes (42-79 min). All patients were followed up to 12 months after the operation. PROMIS PI T-scores decreased significantly from pre-operatively mean 68.6 ± 2.4 to 54.4 ± 1.9 (P < 0.001) and 47.1 ± 4.3 (P < 0.001) at six weeks and 12 months, respectively. PROMIS PF T-scores improved significantly from pre-operatively mean 26.7 ± 4.7 to 44.3 ± 4.2(P < 0.001) and 58.4 ± 4.0 (P < 0.001) at six weeks and 12 months, respectively. No complications and disc herniation recurrences occurred.

CONCLUSION

The targeted full endoscopic laminar trepanning under local anesthesia with a visualized periendoscopic trephine offers a safe, efficient and cost-effective option for the resection of highly migrated LDH.

Full-endoscopic foraminoplasty for highly down-migrated lumbar disc herniation

BACKGROUND AND STUDY AIMS

Multiple surgical approaches have been studied and accepted for the removal of highly downward migrated lumbar disc herniation (LDH). Here, we investigated the efficacy and safety of full-endoscopic foraminoplasty for highly downward migrated LDH.

PATIENTS AND METHODS

Thirty-seven patients with highly down-migrated LDH treated by the full-endoscopic foraminoplasty between January 2018 and January 2020 were retrospectively investigated. Clinical parameters were evaluated preoperatively and 1, 6, and 12 months postoperatively, using pre- and post-operative Oswestry Disability Index (ODI) scores for functional improvement, visual analog scale (VAS) for leg and back pain, and modified MacNab criteria for patients satisfactory.

RESULTS

Thirty-seven patients with highly downward migrated LDH were successfully removed via the transforaminal full-endoscopic discectomy. The average VAS back and leg pain scores were significantly reduced from 7.41 ± 1.17 and 8.68 ± 1.06 before operation to 3.14 ± 0.89 and 2.70 ± 0.46 at postoperative 1 month, and 1.76 ± 0.59 and 0.92 ± 0.28 at postoperative 12 months, respectively (P < 0.05). The average ODI scores were reduced from 92.86 ± 6.41 to 15.30 ± 4.43 at postoperative 1 month, and 9.81 ± 3.24 at postoperative 12 months (P < 0.05). Based on the modifed MacNab criteria, 36 out of 37 patients (97.30%) were rated as excellent or good outcomes.

CONCLUSION

The full-endoscopic foraminoplasty can be used successfully for surgical removal of high grade down-migrated LDH, and it could serve as an efficient alternative technique for patients with highly downward migrated LDH.

A New Grading System for Migrated Lumbar Disc Herniation on Sagittal Magnetic Resonance Imaging: An Agreement Study

Understanding the degree of disc migration is essential in order to diagnose, treat, and assess the prognosis of migrated lumbar disc herniation (LDH). Based on anatomical configuration, we developed a simple six-level grading system for migrated lumbar disc herniation. We aimed to evaluate whether the new grading system was reliable and could replace the previous grading system. We selected 101 cases from our database. Two independent raters evaluated the magnetic resonance images using each grading system. Interobserver, intraobserver, and inter-grading system agreements were assessed using kappa statistics. The most common migration pattern was low-grade inferior migration. Interobserver agreements between the two readers showed substantial agreement in the first and second assessments (k = 0.753 and 0.756, respectively). The intraobserver agreement of reader 1 revealed substantial agreement (k = 0.733), while that of reader 2 revealed almost perfect agreement (k = 0.829). The strengths of the agreements of the new grading system were higher than those of the Lee-Kim grading system. The two grading systems agreed almost perfectly for most measurements. The new grading system was reliable and feasible to determine migrated LDH grade. It allowed for a more intuitive, objective measurement and helped select surgical options.

Foraminoplasty at the Base of the Superior Articular Process with Bone Drilling for Far-Downward Discs in Percutaneous Endoscopic Lumbar Discectomy: A Retrospective Study

Purpose

Percutaneous endoscopic lumbar discectomy (PELD) is usually used to treat lumbar disc herniation (LDH). This study aims to describe PELD by foraminoplasty in the treatment of far-downward migrated LDH and to demonstrate the clinical efficacy by a retrospective evaluation.

Patients and Methods

Between January 2017 and July 2018, 41 patients with far-downward migrated LDH were treated with PELD by foraminoplasty at the base of the superior articular process (SAP). Clinical efficacy was evaluated with a visual analogue scale (VAS) score, the Oswestry disability index (ODI), and the modified Macnab criteria. Postoperative follow-up data (1 month, 6 months, 18 months) were recorded.

Results

The surgical levels included L2/3 (1 patient), L3/4 (1 patient), L4/5 (17 patients), and L5/S1 (22 patients). The VAS and ODI scores indicated a significant improvement 18 months after surgery (mean ± standard deviation, VAS, 6.9±1.3 versus 0.5±0.8; ODI, 66.3±12.2 versus 14.0±8.2, respectively). Based on the modified Macnab criteria, 92.7% of patients had a good-to-excellent rate. There were three patients with a dural tear, and one patient had recurrent disc herniation.

Conclusion

PELD by foraminoplasty at the base of the superior articular process is a good method for treating far-downward migrated LDH.

Surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia for treating elderly patients with lumbar central canal stenosis

OBJECTIVE

Surgical decompression via a posterior interlaminar approach is widely used for treating lumbar central canal stenosis (LCCS). However, this surgical approach poses a challenge for elderly patients with comorbidities. Thus, the authors tried a new surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia to treat such patients. The aim of this study was to evaluate the safety and effectiveness of surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia for patients with LCCS.

METHODS

Patients with LCCS who underwent surgical decompression, performed by a single surgeon, between January 2016 and March 2019 were retrospectively analyzed. All patients received decompression via the unilateral intervertebral foraminal approach with local anesthesia. Visual analog scale (VAS) scores, Oswestry Disability Index (ODI) scores, modified Macnab criteria, walking distance, and Schizas classification were used as outcome predictors. Additionally, a decompression evaluation method was designed for use after spinal endoscopic surgery.

RESULTS

Overall, 23 patients with a mean age of 69 years were included in this study, with a mean follow-up of 28 months. Low-back and leg pain were significantly improved after decompression surgery. Postoperative ODI scores and walking distances were statistically significantly better than before surgery. Postoperatively, the Schizas classification for all patients was improved by at least 1 grade compared with the preoperative grade. No complications occurred during the follow-up period. According to the novel decompression evaluation method, all patients had at least achieved decompression in part 123+B.

CONCLUSIONS

Surgical decompression via the unilateral intervertebral foraminal approach with local anesthesia showed promising outcomes in the treatment of elderly patients with LCCS. Additionally, a proposed postoperative decompression evaluation method can help guide surgical decompression.

TELD with limited foraminoplasty has potential biomechanical advantages over TELD with large annuloplasty: an in-silico study

Background

Facetectomy, an important procedure in the in–out and out–in techniques of transforaminal endoscopic lumbar discectomy (TELD), is related to the deterioration of the postoperative biomechanical environment and poor prognosis. Facetectomy may be avoided in TELD with large annuloplasty, but iatrogenic injury of the annulus and a high grade of nucleotomy have been reported as risk factors influencing poor prognosis. These risk factors may be alleviated in TELD with limited foraminoplasty, and the grade of facetectomy in this surgery can be reduced by using an endoscopic dynamic drill.

Methods

An intact lumbo-sacral finite element (FE) model and the corresponding model with adjacent segment degeneration were constructed and validated to evaluate the risk of biomechanical deterioration and related postoperative complications of TELD with large annuloplasty and TELD with limited foraminoplasty. Changes in various biomechanical indicators were then computed to evaluate the risk of postoperative complications in the surgical segment.

Results

Compared with the intact FE models, the model of TELD with limited foraminoplasty demonstrated slight biomechanical deterioration, whereas the model of TELD with large annuloplasty revealed obvious biomechanical deterioration. Degenerative changes in adjacent segments magnified, rather than altered, the overall trends of biomechanical change.

Conclusions

TELD with limited foraminoplasty presents potential biomechanical advantages over TELD with large annuloplasty. Iatrogenic injury of the annulus and a high grade of nucleotomy are risk factors for postoperative biomechanical deterioration and complications of the surgical segment.

Application of a targeted and quantificational foraminoplasty device in percutaneous transforaminal endoscopic discectomy for L5-S1 disc herniation: preliminary clinical outcomes

OBJECTIVE

Percutaneous transforaminal endoscopic discectomy (PTED) is minimally invasive and has been widely used to treat patients with lumbar disc herniation (LDH) due to its safety and efficiency. However, due to the unique anatomy of the L5-S1 level, the PTED procedure is often difficult to perform in the region. ZESSYS, a targeted and quantificational foraminoplasty device, may help to overcome these anatomical limitations. In this study, we assessed the efficiency and the short-term effects of PTED with ZESSYS at the L5-S1 level.

METHODS

Between January and August of 2018, fifty-six patients with lumbar disc herniation at the single level of L5-S1 and who underwent percutaneous transforaminal endoscopic discectomy were enrolled in this retrospective cohort study. They were segregated into the transforaminal endoscopic surgical system (TESSYS) group and the ZESSYS group. The puncture time, foraminoplasty time, decompression time, and fluoroscopy time were evaluated for operation efficiency. Clinical outcomes were assessed by the visual analog scale (VAS) score and Oswestry Disability Index (ODI) score. The MacNab criteria were used to evaluate patient subjective satisfaction at 12-month follow-up postoperatively.

RESULTS

The average puncture time (5.29 ± 2.05 min), foraminoplasty time (12.82 ± 2.52 min), and fluoroscopy time (26.29 ± 5.96 s) were all significantly shorter in the ZESSYS group than in the TESSYS group (average puncture time 8.07 ± 3.13 min, p < 0.01; foraminoplasty time, 17.18 ± 2.92 min, p < 0.01; fluoroscopy time, 34.73 ± 6.86 s; p < 0.01). No significant differences were observed between the 2 groups in the decompression time (p = 0.057). The VAS score of low back pain and leg pain, as well as the ODI score, improved at all time points postoperatively compared with preoperative, in both the TESSYS group and the ZESSYS group (P < 0.05). There were no significant differences in the VAS score of low back pain, VAS score of leg pain, and ODI score between the TESSYS group and the ZESSYS group at the same time points (P > 0.05). According to the MacNab criteria, the excellent and good rate at 12-month follow-up postoperatively was 85.7% in the TESSYS group and 89.3% in the ZESSYS group (P > 0.05).

CONCLUSION

The targeted and quantificational foraminoplasty device named ZESSYS was more efficient in the puncture and foraminoplasty procedures, effectively protecting the exiting nerve and minimizing the level of radiation exposure. The device is efficient and safe for PTED in treating lumbar disc herniation at the L5-S1 level.

Surgical Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Fusion for Highly Migrated Lumbar Disc Herniation

Objective

To describe minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for highly migrated lumbar disc herniation (LDH) and assess its clinical outcomes.

Patients and Methods

This research retrospectively assessed 25 patients who were diagnosed with one-segmental highly migrated LDH and underwent MIS-TLIF in Peking University First Hospital from June 2015 to September 2019. Demographic data, perioperative parameters, complications, recurrence, and surgical outcomes were assessed.

Results

Twelve males and 13 females, with a mean age of 56.68 years old, were involved and the follow-up period was at least one year. The mean operation time was 222.16 minutes, the mean intraoperative hemorrhage was 250.00 mL, and the mean post-operative hospitalization was 5.76 days. The improvements in visual analog scale (VAS) and Oswestry disability index (ODI) were statistically significant. In addition, based on the MacNab criteria, 22 patients (88.0%) acquired satisfactory (good or excellent) results. One patient underwent post-operative epidural hematoma and recovered after evacuation of the hematoma. No recurrence was found.

Conclusion

MIS-TLIF is safe and effective and it can provide satisfactory clinical outcomes for highly migrated LDH.

Endoscopic and Microscopic Interlaminar Discectomy for the Treatment of Far-Migrated Lumbar Disc Herniation: A Retrospective Study with a 24-Month Follow-Up

Purpose

Percutaneous endoscopic lumbar discectomy for the treatment of far-migrated lumbar disc herniation (LDH) is clinically challenging. The aim of this study was to compare the efficacy and safety of interlaminar endoscopic lumbar discectomy (IELD) and interlaminar microscopic lumbar discectomy (IMLD) for the treatment of far-migrated LDH.

Materials and Methods

We retrospectively analyzed 50 consecutive cases of far-migrated LDH treated by IELD or IMLD. Clinical data and outcomes were assessed before the operation and 1 day and 3, 12, and 24 months after the surgery using the visual analog scale (VAS) and Oswestry disability index (ODI). Modified MacNab criteria were used to evaluate patient satisfaction at the 24-month follow-up.

Results

A significant reduction in leg pain and improvement in ODI (P<0.01) were observed in both groups after surgery. Lower back pain (LBP) was reduced at 24 months postsurgery in the IELD group (P<0.05) but not in the IMLD group (P>0.05). There were significant intergroup differences in VAS LBP score at 1 day and 24 months postsurgery (p=0.01 and 0.02, respectively) and in ODI at 24 months (p=0.03). The rate of excellent or good outcome was 90.32% with IELD and 78.95% with IMLD (p=0.55). Hospital stay and time to ambulation were shorter in the IELD group than in the IMLD group, but the former had a longer operative time (p<0.01). Low and comparable complication rates were reported in the IELD (16.13%) and IMLD (10.53%) groups (p=0.70).

Conclusion

Both IELD and IMLD achieve favorable clinical results in the treatment of far-migrated LDH, with only minor complications. Compared to IMLD, LBP was significantly reduced with IELD presumably because it involved less trauma.

Full Endoscopic Lumbar Foraminoplasty with Periendoscopic Visualized Trephine Technique for Lumbar Disc Herniation with Migration and/or Foraminal or Lateral Recess Stenosis

PURPOSE

To introduce a newly designed periendoscopic visualized trephine system for foraminoplasty in treating lumbar disc herniation with migration and/or foraminal or lateral recess stenosis, and report early clinical outcomes evaluated by the Patient-Reported Outcomes Measurement Information System (PROMIS).

METHODS

A total of 25 patients who underwent transforaminal endoscopic lumbar discectomy with foraminoplasty using a periendoscopic visualized trephine from June 2019 to January 2020 were retrospectively reviewed. PROMIS pain interference and physical function were selected as outcome measures.

RESULTS

The average age of the 25 patients (16 males, 9 females) was 32.0 ± 7.5 years (20-48 years). All patients were successfully followed up with the mean time of 10.1 ± 2.8 months (6-12 months). PROMIS pain interference scores decreased significantly from mean 67.0 ± 3.4 preoperatively to 37.5 ± 5.4 at the final follow-up (P < 0.01), and PROMIS physical function scores improved significantly from mean 29.2 ± 5.5 preoperatively to 59.3 ± 3.7 at the final follow-up (P < 0.01). No neural or vascular complication occurred.

CONCLUSION

Full endoscopic lumbar foraminoplasty with a periendoscopic visualized trephine technique is safe and effective for treating lumbar disc herniation with migration and/or lateral recess or foraminal stenosis, with improved flexibility and convenience and decreased radiation exposure.

Functional outcomes of full-endoscopic spine surgery for high-grade migrated lumbar disc herniation: a prospective registry-based cohort study with more than 5 years of follow-up

BACKGROUND

Full-endoscopic lumbar discectomy (FELD) is an alternative to posterior open surgery to treat a high-grade migrated herniated disc. However, because of the complexity of the surgery, success is dependent on the surgeon's skill. Therefore, patients are frequently treated using open discectomy. Anatomical constraints and technical difficulties can lead to the incomplete removal of high-grade migrated discs.

METHODS

We retrospectively reviewed patients who had undergone FELD performed by a single surgeon between January 2010 and January 2014 from a prospective spine registry in an institute. Perioperative records and data of the Oswestry Disability Index, visual analog scale scores (preoperatively and 2 weeks, 6 weeks, 3 months, 6 months, 1 year, 2 years, and 5 years after the operation), and MacNab criteria were collected.

RESULTS

Of 58 patients with a follow-up duration of > 5 years, (41 and 17 patients had undergone transforaminal endoscopic lumbar discectomy [TELD] and interlaminar endoscopic lumbar discectomy [IELD], respectively), the satisfaction rate was 87.8% (five unsatisfactory cases) for TELD and 100% for IELD. The overall percentage of patients with good to excellent results according to modified MacNab criteria was 91.3% (53/58 patients). Two patients had residual discs. Two patients needed an open discectomy due to recurrent disc herniation. One IELD patient received spinal fusion surgery due to segmental instability after 5 years.

CONCLUSION

FELD has a high success rate for the management of high-grade migrated herniated discs. In patients with high-grade disc migration from L1 to L5, TELD is effective and safe. However, for L4-L5 and L5-S1 high-grade upward and downward disc migration, IELD is the favorable option and provides high patient satisfaction.

Does Robot Navigation and Intraoperative Computed Tomography Guidance Help with Percutaneous Endoscopic Lumbar Discectomy? A Match-Paired Study

OBJECTIVE

To evaluate the efficacy and safety of robot-assisted percutaneous endoscopic lumbar discectomy (rPELD) using a specially designed orthopaedic robot with an intraoperative computed tomography-equipped suite for treatment of symptomatic lumbar disc herniation and compare rPELD with fluoroscopy-assisted percutaneous endoscopic lumbar discectomy (fPELD).

METHODS

We retrospectively reviewed and compared demographic data, radiologic workups, and patient-reported outcomes of 39 patients treated with rPELD and 78 patients treated with fPELD at our institution between January 2019 and December 2019.

RESULTS

Our data showed that a single-shot puncture in the rPELD group was significantly more precise compared with 4.12 ± 1.71 trials in the fPELD group (P < 0.001). There was an overall reduction of fluoroscopy (21.33 ± 3.89 times vs. 33.06 ± 2.92 times, P < 0.001), puncture-channel time (13.34 ± 3.03 minutes vs. 15.03 ± 4.5 minutes, P = 0.038), and total operative time (57.46 ± 7.49 minutes vs. 69.40 ± 12.59 minutes, P < 0.001) using the rPELD technique versus the fPELD technique. However, there were no significant differences in patient-reported outcomes, length of hospital stay, and complication rate between the 2 groups (P > 0.05).

CONCLUSIONS

Taken together, our data indicate that rPELD provides a precise skin entry point and optimal trajectory for puncture, which increases the success rate of PELD, negating the need for revision surgery. However, further studies are required to confirm the superiority and application of the rPELD technique.

Early Clinical Outcomes of Percutaneous Endoscopic Lumbar Discectomy for L4-5 Highly Down-Migrated Disc Herniation: Interlaminar Approach Versus Transforaminal Approach

OBJECTIVE

This study is a retrospective evaluation of patients with L4-5 highly down-migrated lumbar disc herniation (LDH) operated with interlaminar endoscopic lumbar discectomy (IELD) versus transforaminal endoscopic lumbar discectomy (TELD).

METHODS

From January 2015 to December 2018, 77 patients with L4-5 highly down-migrated LDH were divided into 2 groups according to different surgical approaches. There were 40 patients who underwent IELD, and 37 patients who underwent TELD. The operation time, hospital stay, Oswestry Disability Index, clinical outcome according with modified MacNab criteria, Visual Analog Scale (VAS) scores, and complications were compared between the IELD and TELD groups.

RESULTS

Seventy-seven patients were included, 40 and 37 patients underwent IELD and TELD, respectively. The IELD and TELD groups both achieved a significant improvement in Oswestry Disability Index, back and leg VAS scores, and clinical outcome postoperation. Mean operating and x-ray times during operation were significantly shorter in the IELD group than in the TELD group (41.8 vs. 50.3, 1.8 vs. 13.7). There were 3 patients who experienced recurrence in the IELD group and 2 in the TELD group. In the TELD group, there were 3 patients who required revision surgery due to incompletely removed disc fragment. All patients in the IELD group were treated successfully. There was no other complication in these cases.

CONCLUSIONS

Both IELD and TELD could be a good alternative option for highly down-migrated LDH in L4-L5. IELD may have advantages in operation time and x-ray times during operation compared with TELD.

Transpedicular endoscopic removal of highly migrated disc herniations of lumbar spine

Background. Highly migrated disc herniations are usually localized in the area of pars interarticularis medially to the vertebral pedicle. Removal of disk herniations of this localization is a difficult technical task.

The study objective is to demonstrate the effectiveness of the transpedicular endoscopic discectomy in the treatment of patients with highly migrated disc herniations.

Materials and methods. The results of treatment of 12 patients with Macnab zone herniations who were in hospital from 2016 to 2018 were analyzed. All patients underwent transpedicular endoscopic sequestrectomy.

Results. Leg pain after surgery regressed in all patients from the initial 7.41 points (visual-analog scale) to 0.67 points by the end of the 1st day, and it was 0.35 points a year later. The average level of back pain by VAS before surgery was 5.25, on the 1st day after surgery – 1.25 points, 1 year after – 0.67 points. Neurological disorders completely regressed in 10 (91.6 %) patients, there were a slight residual L4 dermatome hypesthesia in 2 patients, without disrupting their quality of life. The average Oswestry Disability Index before surgery was 69.17, and 1 year after surgery was 14.12. There were no complications and reoperations.

Conclusion. Transpedicular endoscopic discectomy allowed us to achieve good treatment results in patients with migration of a lumbar hernia by the pedicle. It can be a safe and effective alternative to the transforaminal or interlaminar endoscopic technique.

Percutaneous Endoscopic Transforaminal Lumbar Discectomy via Eccentric Trepan foraminoplasty Technology for Unilateral Stenosed Serve Root Canals

Objective

To evaluate the clinical outcomes of percutaneous lumbar foraminoplasty for unilateral stenosed nerve root canals.

Methods

The article is a retrospective analysis. From May 2016 to April 2017, 32 patients with lumbar spinal stenosis syndrome (unilateral stenosed nerve root canals) were treated with percutaneous endoscopic transforaminal lumbar discectomy (PETLD). The study included 15 men and 17 women, with an average age of 53.8 ± 15.4 years, ranging from 24 to 78 years. The indexes used for preoperative and postoperative 1 day, 3 months, and final follow up were the visual analogue scale (VAS) for lumbar and leg, the Oswestry disability index (ODI), and the modified Macnab criteria. All patients were followed up for an average 6 months after the operation.

Results

The average operative time was 75.82 ± 10.58 min, the average blood loss was 15.83 ± 3.75 mL, and the average hospital stay after surgery was 6.2 ± 4.6 days. The VAS score (leg) decreased from 6.94 ± 0.50 preoperatively to 1.16 ± 0.45 at the final follow up (P < 0.05) and ODI were obviously improved, from preoperative evaluation of 80.19 ± 5.55 to 9.44 ± 1.16 at the final follow up (P < 0.05). However, the postoperative VAS score (lumbar) did not show an improvement, reducing from 1.78 ± 0.49 preoperatively to 1.62 ± 0.55 at the final follow‐up (P > 0.05). According to the modified Macnab criteria, the outcome showed that the excellent and good rate was 90.6%. There were three patients with hip soreness, and nerve root symptoms were relieved.

Conclusion

Percutaneous endoscopic transforaminal lumbar discectomy has a satisfactory clinical effect in the treatment of lumbar spinal stenosis syndrome, especially for unilateral stenosed nerve root canals, and in decompressing the lateral recess and relieving the nerve root symptoms.

The Evolution of Transforaminal Endoscopic Spine Surgery

Transforaminal endoscopic spine surgery (T-ESS) has become a well-accepted technique. The first attempts at percutaneous discectomy by Kambin and Hijikata opened a new chapter of endoscopic spine surgery. By the last quarter of the twentieth century, spine surgeons had begun to adopt this novel technique. Many researchers helped advance endoscopic spine surgery, but the turning point was the description of a safe transforaminal triangle of safety by Parviz Kambin. Since then, the indications for T-ESS have increased as a result of the description of different surgical approaches such as inside-out, outside-in, and half-and-half. We present a review of crucial historical advancements in T-ESS and also discuss the evolution of endoscopes, the techniques used, development of endoscopic instruments and equipment, transforaminal thoracic endoscopy, transforaminal endoscopic interbody fusions, the growth of extended indications, and the future direction of T-ESS. This review provides a detailed description of key historical moments and a bird's-eye view of the vast scope of T-ESS.

Suprapedicular Retrocorporeal Technique of Transforaminal Full-Endoscopic Lumbar Discectomy for Highly Downward-Migrated Disc Herniation

OBJECTIVE

Anatomical barriers (e.g., pedicles, narrow foramina) can hinder direct access to, and removal of, disc fragments that have migrated far downward. Using transforaminal full-endoscopic lumbar discectomy (FELD), we devised a modified technique, the suprapedicular retrocorporeal approach, for herniations in which the disc has migrated to the axilla of the traversing nerve roots. In the present report, we have described our preliminary results.

METHODS

Soft, highly downward-migrated disc herniation was treated with transforaminal FELD through the suprapedicular retrocorporeal approach in 22 patients from June 2017 to May 2019. The clinical outcomes were evaluated, including the preoperative and postoperative visual analog scale scores for the back and leg, Oswestry disability index, and MacNab criteria for surgical success.

RESULTS

The affected discs were at L4-L5 in 14 patients, L3-L4 in 6 patients, and L5-S1 in 2 patients. In each case, the affected disc was successfully removed using the suprapedicular retrocorporeal approach. The mean follow-up was 18.1 ± 5.7 months. The mean visual analog scale scores for back and leg pain improved significantly (P < 0.05 for both). The mean Oswestry disability index had decreased from 62.5 ± 14.2 preoperatively to 10.5 ± 5.9 postoperatively (P < 0.05). Using the MacNab criteria, 13 patients reported excellent outcomes and 9, good outcomes. No complications or recurrence developed during follow-up.

CONCLUSIONS

The suprapedicular retrocorporeal technique is a feasible and effective surgical option in transforaminal FELD for the treatment of herniation in which the disc has migrated to the axilla of the traversing nerve roots.

A Historical Review of Endoscopic Spinal Discectomy

As an essential component of minimally invasive spine surgery, endoscopic spine surgery (ESS) has continuously evolved and has been accepted as a practical procedure by the worldwide spine community. Especially for lumbar disc herniation (LDH), the percutaneous endoscopic or full-endoscopic discectomy technique has been scientifically proven through randomized controlled trials and meta-analyses to be a good alternative to open discectomy. The initial concept of endoscopic spine discectomy was concerned with indirect disc decompression using various instruments such as blind forceps, a nucleotome, laser, radiofrequency coblation, and some chemical agents. The main surgical field has been shifted from the intradiscal space to the epidural space. Precise and selective discectomy for extruded LDH in the epidural space under high-quality endoscopic visualization is now feasible. Furthermore, the medical applications of ESS is broadening to include spinal stenosis, segmental instability, infection, and even intradural lesions. In this review article, I describe the history of endoscopic spine discectomy and decompression techniques, as well as evolution of the paradigm. This history may help indicate the future of practical ESS.

Transforaminal Endoscopic Lumbar Discectomy for L5-S1 Disc Herniation With High Iliac Crest: Technical Note and Preliminary Series

With the trend of minimally invasive spine surgery, full-endoscopic lumbar discectomy (FELD) has evolved with the advancement of the optics and instruments. Regarding the techniques, the transforaminal and interlaminar approach remain the major accesses in FELD. Transforaminal endoscopic lumbar discectomy (TELD) is an effective and safe treatment for herniation of the lumbar disc. More and more evidence supports the TELD in enhancing recovery and decreasing surgical complications. However, the learning curve of TELD remains steep, especially at the L5-S1 level. The iliac crest height is an essential factor in the operability of TELD at the L5-S1 level. In the situation of the high iliac crest, TELD is technically challenging even for an experienced surgeon. Therefore, the authors report their techniques of TELD with foraminoplasty step-by-step and the preliminary results in this report.

Technical Considerations in Endoscopic Lumbar Decompression

With technical development and evolution of endoscopic instruments, endoscopic spinal surgery has become one of the standard treatments for various lumbar spinal diseases ranging from a simple contained disc to complicated cases such as highly migrated disc herniation and other pathology combined with bony degeneration to produce foraminal and canal stenosis. Favorable clinical results of endoscopic decompression for lumbar stenotic disease were reported by several authors. However, studies have also reported limitations, such as steep learning curves and a relatively high complication rate compared with conventional techniques. The endoscopic lumbar decompression technique consists of many essential skills to manage different endoscopic anatomic structures of the spine. From the perspective of surgical completion and safety, this article discusses issues related to technical considerations in endoscopic lumbar decompression.

Full endoscopic interlaminar discectomy (FEID) for recurrent lumbar disc herniation: surgical technique, clinical outcome, and prognostic factors

Background

The objective of this study is to determine the effectiveness and prognostic factors of revisional full endoscopic interlaminar discectomy (FEID) for recurrent herniation after conventional open disc surgery. The major concerns of the repeated discectomy for recurrent lumbar disc herniation (RLDH) are the epidural scar and postoperative segmental instability. Compared to open discectomy, endoscopic method has advantages of less tissue traumatization, clearer visualization and better tissue identification. With the improvement of endoscopic technique and instrument, the problems related to adhesive scar tissues or postoperative instability could be overcome.

Methods

From June 2014 to December 2016, FEID was performed in consecutive 24 patients for RLDH. The age ranged from 25 to 60 years (mean 44.6 years). The level operated was L5-S1 in 16 cases and L4-5 in 8 cases. To avoid injury to the neural tissue, we started with the bony structure. A small part of facet or lamina might be resected in severe stenotic or adhesive condition. Aggressive separation of the scar from the neural tissue might lead to dural tear and should be avoided. The herniated disc material was removed after neural tissue had been clearly identified and protected.

Results

The follow-up period was at least 24 months. The visual analog scale (VAS) for leg pain and back pain, and Oswestry disability index (ODI) showed significant improvement after treatment. Excellent or good outcome by the modified Macnab's criteria was obtained in 22 of 24 patients at two years follow-up. Excellent outcome was noted in 100 percent patients younger than 50 years. Small durotomy occurred in 2 patients and no visible cerebrospinal fluid (CSF) leakage was detected despite repair was not performed. Two additional surgery was performed including one repeated FEID for re-recurrence of disc herniation and one fusion surgery for postoperative back pain.

Conclusions

FEID is a safe and effective alternative for recurrent disc herniation. The successful rate was greater than 90 percent, especially in the younger patients with the advantages of early recovery and no need for fusion.

Percutaneous Transforaminal Endoscopic Removal of Spinal Shrapnel

BACKGROUND

Gunshot injuries are one of the most common causes of the penetrating injuries of the spine. The victims of these injuries usually have neurologic deficits. Percutaneous endoscopic lumbar surgery is one of the most popular surgical spine interventions. We report a case with incomplete radiculopathy due to shrapnel located in L5 foramen that was removed by percutaneous endoscopic technique.

CASE DESCRIPTION

A 23-year-old man sustaining a gunshot injury penetrating to the abdomen presented to our hospital. His first examination revealed a single gunshot wound with entry hole in the left low lumbar region without exit hole and right lower abdominal quadrant tenderness. Plain radiographs and computed tomography showed a bullet in the abdomen and left L5 transverse process fracture and shrapnel in L5 foraminal zone. The bullet was removed by abdominal surgeons without any surgical plan for the shrapnel in the foramen. He was referred to our clinic 3 weeks after discharge. Without any further neurologic deterioration, he had uninterrupted severe pain that was mostly unbearable during the night. Despite gradually increasing dosages of different drugs, his pain relief was insufficient. Percutaneous transforaminal endoscopic removal of the shrapnel was planned.

CONCLUSIONS

Despite the absence of a universally approved algorithm in the treatment of spinal gunshot injuries, endoscopic technique can be kept in mind for a minimal access and invasiveness in case of indication for removal. With experience in endoscopic procedures and familiarity with surgical anatomy, the treatment of this unique case was completed successfully.

Effect of Percutaneous Endoscopic Lumbar Foraminoplasty of Different Facet Joint Portions on Lumbar Biomechanics: A Finite Element Analysis

Objective

To evaluate the influence of percutaneous endoscopic lumbar foraminoplasty of different facet joint portions on segmental range of motion (ROM) and intradiscal pressure (IDP) of L₃/L₄ and L₄/L₅ motion segments by establishing three dimensional finite element (FE) model.

Method

Computed tomography images of a male adult volunteer of appropriate age and in good condition both mentally and physically. Obtained data was used in this study from July 2020 to December 2020, and an intact L_3–5 three dimensional finite element model was successfully constructed using ANSYS and MIMICS software (model M1). The M1 was modified to simulate the foraminoplasty of different facet joint portions, with unilateral cylindrical excision (diameter = 0.75 cm) performed on the tip (model M2) and the base (model M3) of right L₅ superior facet elements along with surrounding capsular ligaments, respectively. Under the same loading conditions, the ROM and IDP of L₃/₄ and L₄/L₅ segments in states of forward flexion, backward extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation were all compared.

Result

Compared with the intact model in backward extension, M2 increased the ROM of L_4/5 segment by 9.4% and IDP by 11.7%, while the ROM and IDP of M3 changed only slightly. In right axial rotation, M2 and M3 increased the ROM of L_4/5 segment by 17.9% and by 3.6%, respectively. In left axial rotation, M2 and M3 increased the ROM of L₄/L₅ segment by 7.14% and 3.6%, respectively. As for other states including forward flexion, left lateral bending, right lateral bending, the ROM and IDP were not significantly distinct between these two models. While focusing on L₃/L₄ segment, obviously changes in the ROM and IDP have not been presented and neither M2 nor M3 changed in any loading condition.

Conclusion

This study provides evidence that the base‐facet foraminoplasty of L₅ superior facet provided a higher segmental stability compared with the tip‐facet foraminoplasty in flexion and axial rotation. Meanwhile, it also shows the two types of foraminoplasty make few differences to the L_4/5 segmental biomechanics. Besides, it does not appear to impact the stability of L₃/L₄ in six states of forward flexion, backward extension, left lateral bending, right lateral bending, left axial rotation and right axial rotation when superior facet of L₅ was partially removed. These findings might be useful in understanding biomechanics of the lumbar spine after foraminoplasty performed on different portions of the facet, thus providing endoscopic surgeons a better reference for operational approach to maintain the function and mobility of the spine.