An extreme lateral access for the surgery of lumbar disc herniations inside the spinal canal using the full-endoscopic uniportal transforaminal approach-technique and prospective results of 463 patients

New ipsilateral full endoscopic interlaminar approach for L5-S1 foraminal and extraforaminal decompression: technique description and initial case series

BACKGROUND

The L5-S1 interlaminar access described in 2006 by Ruetten et al. represented a paradigm shift and a new perspective on endoscopic spinal approaches. Since then, the spinal community has shown that both the traditional ipsilateral and novel contralateral interlaminar approaches to the L5-S1 foramen are good alternatives to transforaminal access. This study aimed to provide a technical description and brief case series analysis of a new endoscopic foraminal and extraforaminal approach for pathologies at the lumbar L5-S1 level using a new ipsilateral interlaminar approach.

METHODS

Thirty patients with degenerative stenotic conditions at the L5-S1 disc level underwent the modified interlaminar approach. The surgical time, blood loss, occurrence of complications, and clinical outcomes were recorded. The data were compiled in Excel and analyzed using R software version 4.2. All continuous variables are presented as the mean, median, minimum, and maximal ranges. For categorical variables, data are described as counts and percentages.

RESULTS

Thirty patients were included in the study. The cohort showed significant improvements in all quality-of-life scores (ODI, visual analog scale of back pain, and visual analog scale of leg pain). Five cases of postoperative numbness and three cases of postoperative dysesthesia have been reported. No case of durotomy or leg weakness has been reported.

CONCLUSIONS

The fundamental change proposed by this procedure, the new ipsilateral approach, presents potential advantages to surgeons by overcoming anatomical challenges at the L5-S1 level and by providing surgeon-friendly visualization and access. This approach allows for extensive foraminal and extraforaminal decompression, including the removal of hernias and osteophytosis, without causing neural retraction of the L5-S1 roots while maintaining the stability of the operated level.

A Novel Classification of Migrated Lumbar Disk Herniation Based on Magnetic Resonance Imaging and Algorithm Recommendations for Full-Endoscopic Discectomy

STUDY DESIGN

Retrospective clinical study.

OBJECTIVE

The purpose of this study was to establish a novel classification of migrated lumbar disk herniation (LDH) based on magnetic resonance imaging and provide appropriate treatment strategies for each type through algorithms.

SUMMARY OF BACKGROUND DATA

Full-endoscopic lumbar discectomy is a surgical technique that has been developed rapidly in recent years. For migrated LDH, few surgeons currently classify it with multiplanar positioning, and there is no consensus on the choice of treatment strategy. Therefore, we established a new multiplanar classification criteria that can localize the lesions more accurately than previous studies.

METHODS

A total of 263 eligible patients from March 2017 to March 2022 were included. Protrusions for each patient were located based on our classification and the surgical approach was selected according to our algorithms. The clinical symptoms of all patients before surgery, and at 1 day, 1 month, 3 months, 6 months, and 12 months after surgery were collected. Evaluations were performed using visual analogue scale (VAS), Oswestry Disability Index (ODI) and modified MacNab criteria. We used the chi-squared test, one-way analysis of variance (ANOVA), and t-test to compare perioperative results and postoperative 3-month, 6-month, and 12-month follow-up results.

RESULTS

VAS (low back pain) scores were reduced from 5.33 ± 2.67 to 0.73 ± 0.77 (p < 0.001), and VAS (leg pain) scores were reduced from 7.44 ± 2.21 to 0.37 ± 0.51 (p < 0.001). ODI scores improved from 58.46 ± 8.04 to 12.57 ± 2.51 (p < 0.001). According to the modified MacNab criteria, the excellent and good rate reached 92.78% at the 12-month follow-up. Twenty-six patients developed complications, all of which improved after treatment. Recurrence occurred in 13 patients, and four of them underwent secondary surgery.

CONCLUSIONS

This is an innovative classification method using multi-plane positioning, and the algorithm used with it can help surgeons make appropriate choices when using endoscopic technology to treat migrated LDH. Statistical analysis of follow-up data confirmed that this is a safe and effective strategy.

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.

Enhancing contrast distribution with the far lateral approach in lumbar transforaminal epidural steroid injections: A retrospective analysis

BACKGROUND

Herniated intervertebral disc (HIVD) with radiculopathy is a common degenerative spine disorder. Transforaminal epidural steroid injection (TFESI) is one of the pain relief treatments for lumbar radiculopathy recommended by evidence-based guidelines. Adequate contrast distribution is correlated with better pain control, but the best approach has not been confirmed yet.

AIM

To confirm the distribution of contrast medium injected with a new approach of TFESI, that is, far lateral lateral recess approach (FLLR-TFESI).

METHODS

Patients receiving TFESI due to HIVD with radiculopathy between 2010 January and 2020 August were retrospectively enrolled. While the FLLR-TFESI was taken as the experimental group, the conventional approach was viewed as the control group. The baseline characteristics, the pattern of contrast enhancement under fluoroscopic guidance, and the complications of these patients were collected and analyzed.

RESULTS

A total of 380 patients were analyzed (143 in control group and 237 in experimental group). The two groups were balanced in most baseline characteristics, except disc extrusion (p = 0.01) and scoliosis (p = 0.04). The FLLR-TFESI have a better contrast distribution (p < 0.01), even after adjustment (p < 0.001). No intrathecal injection was noted, but higher rate of intra-disc injection was noted in FLLR-TFESI group (10% vs. 3%, p = 0.008).

CONCLUSION

The FLLR-TFESI has a superior contrast enhancement and distribution in comparison to conventional approach. Prospective study to confirm the study result as well as the clinical benefits is suggested in the future.

Management for degenerative lumbar spondylolisthesis: a network meta-analysis and systematic review basing on randomized controlled trials

BACKGROUND

Consensus on the various interventions for degenerative lumbar spondylolisthesis (DLS) remains unclear.

MATERIALS AND METHODS

The authors searched PubMed, Embase, Cochrane Library, Web of Science, and major scientific websites until 01 November 2023, to screen eligible randomized controlled trials (RCTs) involving the treatment of DLS. The seven most common DLS interventions [nonsurgical (NS), decompression only (DO), decompression plus fusion without internal fixation (DF), decompression plus fusion with internal fixation (DFI), endoscopic decompression plus fusion (EDF), endoscopic decompression (ED), and circumferential fusion (360F)] were compared. The primary (pain and disability) and secondary (complications, reoperation rate, operation time, blood loss, length of hospital stay, and satisfaction) outcomes were analyzed.

RESULTS

Data involving 3273 patients in 16 RCTs comparing the efficacy of different interventions for DLS were reported. In terms of improving patient pain and dysfunction, there was a significant difference between surgical and NS. EDF showed the greatest improvement in short-term and long-term dysfunction (probability, 7.1 and 21.0%). Moreover, EDF had a higher complication rate (probability 70.8%), lower reoperation rate (probability, 20.2%), and caused greater blood loss (probability, 82.5%) than other surgical interventions. Endoscopic surgery had the shortest hospitalization time (EDF: probability, 42.6%; ED: probability, 3.9%). DF and DFI had the highest satisfaction scores.

CONCLUSIONS

Despite the high complication rate of EDF, its advantages include improvement in pain, lower reoperation rate, and shorter hospitalization duration. Therefore, EDF may be a good option for patients with DLS as a less invasive surgical approach.

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.

The Endoscopic Lumbar Interbody Fusion: A Narrative Review, and Future Perspective

Lumbar interbody fusion stands as a preferred surgical solution for degenerative lumbar spine diseases. The procedure primarily aims to establish lumbar segment stability, directly addressing patient symptoms associated with spinal complications. Traditional open surgery, though effective, is linked with notable morbidities and extended recovery time. To mitigate these concerns, minimally invasive surgery (MIS) has garnered significant popularity, presenting an appealing alternative with numerous benefits such as reduced soft tissue trauma, decreased blood loss, and expedited recovery. Among MIS procedures, full endoscopic spinal surgery, characterized by its minimal invasiveness, holds the potential to further minimize morbidities while enhancing surgical outcomes. Endoscopic lumbar interbody fusion, a novel procedure within this paradigm, has gained attention for offering advantages comparable to those of minimally invasive transforaminal lumbar interbody fusion. However, the safety, efficacy, and associated surgical techniques and instrument design of this method continue to be subjects of ongoing debate. This paper critically reviews current evidence on the safety, efficacy, and advantages of endoscopic lumbar spinal interbody fusion, examining whether it could indeed supersede existing mainstream techniques.

Functional Outcomes After Discectomy for Recurrent Lumbar Herniation Using the Destandau Endospine System: A Retrospective Study of 44 Patients

Background Recurrent disc herniation is a major cause of morbidity and surgical failure after disc surgery. This study aimed to investigate the feasibility, safety, and effectiveness of the Destandau endospine system (DES) for treating recurrent lumbar disc herniation (LDH). Methodology A total of 44 patients who underwent minimally invasive Destandau endoscopic lumbar discectomy (DELD) for recurrent LDH were included in this study. All data were collected retrospectively. The preoperative and postoperative visual analog scale (VAS) score was used for the evaluation and gradation of pain. The clinical outcome was analyzed according to modified MacNab criteria. The minimum follow-up was two years. Preoperative and postoperative VAS scores were compared using the paired Student's t-test. Statistical significance was set at a p-value <0.05. Results The mean surgical time was 30 ± 20 minutes. The VAS score for leg pain was improved in all cases from 5.9 ± 2.1 to 1.7 ± 1.3 (p< 0.001). In 98% of cases, a successful outcome was noted (excellent or good outcome according to MacNab criteria). In three (7%) patients, incidental durotomy occurred, but there was no neurological worsening, cerebrospinal fluid fistula, or negative influence on the clinical outcome. No recurrence or instability occurred in our series. Conclusions The clinical outcomes of minimally invasive DES for LDH were found to be comparable with the reported success rates of other minimally invasive techniques reported in the existing literature. The dural tear rate was independent of postoperative morbidity and functional outcome. The technique is a safe and effective treatment option for recurrent LDH.

Minimally invasive endoscopy in spine surgery: where are we now?

INTRODUCTION

Endoscopic spine surgery (ESS) is a minimally invasive surgical technique that offers comparable efficacy and safety with less collateral damage compared to conventional surgery. To achieve clinical success, it is imperative to stay abreast of technological advancements, modern surgical instruments and technique, and updated evidence.

PURPOSES

To provide a comprehensive review and updates of ESS including the nomenclature, technical evolution, bibliometric analysis of evidence, recent changes in the spine communities, the prevailing of biportal endoscopy, and the future of endoscopic spine surgery.

METHODS

We conducted a comprehensive review of the literature on ESS for the mentioned topics from January 1989 to November 2022. Three major electronic databases were searched, including MEDLINE, Scopus, and Embase. Covidence Systematic Review was used to organize the eligible records. Two independent reviewers screened the articles for relevance.

RESULTS

In total, 312 articles were finally included for review. We found various use of nomenclatures in the field of ESS publication. To address this issue, we proposed the use of distinct terms to describe the biportal and uniportal techniques, as well as their specific approaches. In the realm of technical advancement, ESS has rapidly evolved from addressing disc herniation and spinal stenosis to encompassing endoscopic fusion, along with technological innovations such as navigation, robotics, and augmented reality. According to bibliometric analysis, China, South Korea, and the USA have accounted for almost three-quarters of total publications. The studies of the biportal endoscopy are becoming increasingly popular in South Korea where the top ten most-cited articles have been published. The biportal endoscopy technique is relatively simple to adopt, as it relies on a more familiar approach, requires less expensive instruments, has a shorter learning curve, and is also well-suited for interbody fusion. The uniportal approach provided the smallest area of soft tissue dissection. While robotics and augmented reality in ESS are not widely embraced, the use of navigation in ESS is expected to become more streamlined, particularly with the emergence of recent electromagnetic-based navigation technologies.

CONCLUSIONS

In this paper, we provide a comprehensive overview of the evolution of ESS, as well as an updated summary of current trends in the field, including the biportal and uniportal approaches. Additionally, we summarize the nomenclature used in ESS, present a bibliometric analysis of the field, and discuss future directions for the advancement of the field.

The effectiveness and safety of annulus closure device implantation in lumbar discectomy for patients with lumbar disc herniation: a systematic review and meta-analysis

OBJECTIVE

The objective of this study was to systematically estimate the effectiveness and safety of annulus closure device (ACD) implantation in discectomy for patients with lumbar disc herniation (LDH).

METHODS

A systematic search was performed on PubMed, EMBASE and the Cochrane Library for randomized controlled trial (RCT) from inception until April 16, 2022. Trials which investigated comparisons between with and without ACD implantation in discectomy for LDH patients were identified.

RESULTS

In total, five RCTs involving 2380 patients with LDH underwent discectomy were included. The included patients were divided into ACD group and control group (CTL). Significant differences were found in the rate of re-herniation (ACD: 7.40%, CTL: 17.58%), reoperation (ACD: 5.39%, CTL: 13.58%) and serious adverse event (ACD: 10.79%, CTL: 17.14%) between ACD group and CTL group. No significant difference was found in VAS-BACK, VAS-LEG, ODI and SF-12 PCS between ACD and CTL. The surgical time of ACD was longer than CTL with statistical significance. In subgroup analyses based on discectomy type, significant differences were found in the rate of re-herniation (ACD: 10.73%, CTL: 21.27%), reoperation (ACD: 4.96%, CTL: 13.82%) and serious adverse event (ACD: 7.59%, CTL: 16.89%) between ACD and CTL in limited lumbar discectomy (LLD).

CONCLUSION

Discectomy either with or without ACD implantation is considered to achieve similar clinical outcomes. Whereas, the ACD implantation in LLD is associated with lower re-herniation and reoperation rate but prolonged surgical time for LDH patients. Researches on cost-effectiveness and effect of ACD implantation in different discectomy are needed in the future.

A modified percutaneous transforaminal endoscopic surgery for central calcified thoracic disc herniation at the T11/T12 level using foraminoplasty and decompression: A case report

Background

Thoracic disc herniation (TDH) is uncommon. Central calcified TDH (CCTDH) is even rare. Traditional open surgery was considered a gold standard to treat CCTDH, but it was accompanied by a high risk of complications. Recently, a technique called percutaneous transforaminal endoscopic decompression (PTED) was adopted to treat TDH. Gu et al. designed a simplified PTED technique and named it percutaneous transforaminal endoscopic surgery (PTES) to treat various types of lumbar disc herniation; it offered the advantages of simple orientation, easy puncture, reduced steps, and little x-ray exposure. However, PTES to treat CCTDH has not been reported in the literature.

Methods

Here, we describe the case of a patient with CCTDH treated with a modified PTES through the unilateral posterolateral approach under local anesthesia and conscious sedation by using a flexible power diamond drill. First, we report that the patient was treated with PTES with later-stage endoscopic foraminoplasty, with an inside-out technique employed at the initial endoscopic decompression stage.

Results

A 50-year-old male with progressive gait disturbance and bilateral leg rigidity with paresis and numbness was diagnosed with CCTDH at the T11/T12 level on MRI and CT examinations. A modified PTES was performed on November 22, 2019. The total mJOA (modified Japanese Orthopedic Association) score preoperatively was 12. The method of the determination of incision and the soft tissue trajectory establishment process were the same as those in the original PTES technique. The foraminoplasty process was divided into initial fluoroscopic and final endoscopic stages. At the fluoroscopic stage, the hand trephine's saw teeth were just rotated into the lateral portion of the ventral bone from the superior articular process (SAP) to seize the SAP firmly, while at the endoscopic stage, in order to remove the ventral bone from the SAP safely under direct endoscopic visualization, adequate foramen enlargement was achieved without causing any risk of damage to the neural structures in the spinal canal. During the endoscopic decompression process, the soft disc fragments ventral to the calcified shell were undermined to form a cavity using an inside-out technique. Then, a flexible endoscopic diamond burr was introduced to degrade the calcified shell, and a curved dissector or a flexible radiofrequency probe was used to dissect the thin bony shell from the dural sac. Eventually, the shell was fractured within the cavity piece by piece to remove the whole CCTDH and achieve adequate dural sac decompression, resulting in minimal blood loss and no complications. The symptoms were gradually alleviated and the patient almost completely recovered at the 3-month follow-up, with no symptom recurrence found at the 2-year follow-up. The mJOA score improved to 17 at the 3-month follow-up and to 18 at the 2-year follow-up compared with 12 points preoperatively.

Conclusions

A modified PTES may be an alternative minimally invasive technique for the treatment of CCTDH and provide similar or better outcomes over traditional open surgery. However, this procedure requires good endoscopic experience on the part of the surgeon and is beset with technical challenges and therefore should be performed with utmost care.

A Modified Endoscopic Access for Lumbar Foraminal Pathologies; Posterolateral “Intertransverse” Endoscopic Approach to Minimize Postoperative Dysesthesia Following Transforaminal Approach

Objective: To present an innovative, modified endoscopic approach for foraminal/extraforaminal pathologies, to reduce postoperative dysesthesia (POD) following the conventional transforaminal endoscopic approach (the access angle more than 45° from the midline), since POD is one of the major documented disadvantages that may compromise patient satisfaction.Methods: We introduce a modified posterolateral technique, termed the intertransverse approach, utilizing a steeper access angle less than 25° through the intertransversarii muscle and the intertransverse space with expanding Kambin triangle via lateral facetectomy/foraminoplasty, to reduce dorsal root ganglion/exiting nerve root irritation under direct visualization and lower the incidence of POD. Consecutive patients undergoing endoscopic spine surgery via the intertransverse approach for foraminal and/or extraforaminal disc herniations or bony stenosis were retrospectively reviewed. Clinical outcomes were reviewed with the primary outcome being POD.Results: Twenty-two patients were included in the review. Patients showed significantly improved clinical outcomes (visual analogue scale leg and back pain and Oswestry Disability Index) postoperatively. There was a low rate of dorsal root ganglion (DRG)-related POD (9.1%, 2 of 22) that was minimal and resolved soon.Conclusion: The inter-transverse endoscopic approach is feasible for lumbosacral foraminal and extraforaminal decompression with significantly improved clinical outcomes and the added advantage of a low rate of DRG-related POD compared to traditionally reported rates in the literature for the conventional transforaminal approach.

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.

Ultrasound-Guided In-Plane Interlaminar Lumbar Endoscopic Approach with Smartphone and Portable Light Source: Description of a New Surgical Technique

Introduction Endoscopic spine surgery enables the minimally invasive treatment of pathologies affecting the spinal cord and roots. Herein we describe an unprecedented technique Ultrasound-Guided in-plane interlaminar lumbar endoscopic approach with a smartphone and portable light source.

Methods The interlaminar approach was performed in a cadaveric specimen at L4 to 5 and L5 to S1 bilaterally. A curvilinear 2 to 5 MHz ultrasound probe was employed, the puncture was performed with the needle, a guide wire was inserted until the flavum ligament, followed by the dilator and working cannula. A 30° spinal endoscope, with an optical adapter of the endoscope camera for smartphone and portable endoscope lighting was inserted, the flavum ligament was visualized, and an opening in this site was performed with the scissors. Open dissection of the specimen was subsequently performed by identifying the puncture site in the interlaminar window.

Results The four interlaminar punctures were successfully guided by ultrasound; the opening of the ligamentum flavum was performed in the most lateral part of the interlaminar space, near the junction of the superior and inferior articular processes of the corresponding vertebrae in all the punctures.

Discussion The ultrasound makes possible to identify facets, foramina, transverse processes, and the interlaminar space. It is possible to minimize the use of radioscopy and its associated risks, both for patients and health professionals.

Conclusions The ultrasound-guided, in-plane, interlaminar, lumbar endoscopic approach with smartphone-adapted endoscope and portable light source is feasible and practical, minimizing radiation risks and making it possible to perform endoscopic spinal surgery.

Transforaminal endoscopic lumbar discectomy with targeted puncture and foraminotomy for very highly migrated disc herniation: A technique note with case series

Background

Transforaminal endoscopic lumbar discectomy (TELD) has been widely used for lumbar disc herniation. However, in some challenging cases such as very highly migrated disc herniation (VHMDH), traditional TELD is difficult to access the pathology.

Methods

From January 2016 to December 2019, 63 patients with single-level VHMDH underwent TELD using targeted puncture and foraminotomy techniques were included. All patients were followed up for 26.5 months on average (range, 24–48 months). Operative time, length of hospital stay, visual analog scale (VAS) score, Oswestry Disability Index (ODI), modified MacNab criteria and surgical complications were evaluated.

Results

The operative time was 40–120 min (56.8 on average). The length of hospitalization was 2.5 days (range, 2–4 d). VAS score decreased significantly from 5.5 ± 1.3 preoperatively to 1.9 ± 1.30 (p < 0.001) 1 day postoperatively, and to 0.9 ± 0.8 (p < 0.001) at the final follow-up. ODI score improved significantly from 23.5 ± 3.2 preoperatively to 13.4 ± 3.0 (p < 0.001) 1 day postoperatively; and 3.1 ± 1.2 (p < 0.001) at the final follow-up. According to the modified MacNab criteria, 40 patients (63.5%) showed excellent results, 20 patients (31.7%) were rated as good, 2 patients (3.2%) were rated as fine, and 1 patient (1.6%) was rated as bad at the final follow-up. No residual fragments, nerve root or cauda equina injury was shown in this series. One recurrent case was resolved by open surgery.

Conclusions

With modified targeted puncture and foraminotomy techniques, VHMDH can be accessed safely and effectively, and satisfactory clinical outcomes can be obtained for these patients.

The Future of Minimally Invasive Spinal Surgery

Strong forces are pushing minimally invasive spinal surgery (MISS) to the forefront of spine care. Less-invasive surgical techniques have been enabled by a variety of technical advances. Despite the promise of MISS, however, several factors, including few training opportunities, perception of a steep learning curve, and high upfront costs, have limited the adoption of these techniques. The "6 T's" is a framework highlighting key factors that must be accounted for to ensure safe and effective MISS as techniques continually evolve. Further, technological advancement in endoscopy, robotics, and augmented/virtual reality is enhancing minimally invasive surgeries to make them even less invasive and safer for patients. The evolution of these new techniques and technologies is driving the future of MISS.

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.

Comparison of Endoscopic Discectomy Versus Non-Endoscopic Discectomy for Symptomatic Lumbar Disc Herniation: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review.

OBJECTIVE

The authors aimed to systematically compare the effectiveness and safety of endoscopic discectomy (ED) with non-endoscopic discectomy (NED) for treatment of symptomatic lumbar disc herniation (LDH).

METHODS

A systematic search was performed on PubMed, EMBASE, the Cochrane Library and China National Knowledge Infrastructure for randomized controlled trial from inception until August 13, 2020. Trials which investigated multiple operative approaches on lumbar disc herniation were identified without language restrictions.

RESULTS

In total, 25 trials involving 2258 patients with symptomatic LDH were included. Twenty trials performed the comparison between ED and NED. Five trials performed the comparison between percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID). The operative time of micro-endoscopic discectomy (MED) was longer than open discectomy (OD). The length of hospital stay of percutaneous endoscopic lumbar discectomy (PELD) was shorter than fenestration discectomy (FD). Significant differences in intraoperative blood loss volumes were found between PELD with FD and MED with OD. The complication rate of PELD was lower than FD (PELD: 4.3%; FD: 14.6%) and the complication rate of full-endoscopic discectomy (FE) was lower than microscopic discectomy (MD) (FE: 13.4%; MD: 32.1%).

CONCLUSIONS

PELD and FE have the advantage of limiting intraoperative damages. ED and NED can be both considered sufficient to achieve good clinical outcomes. PETD and PEID are able to achieve similar results but the learning curve of PETD was steeper. More independent high-quality RCTs with sufficiently large sample sizes performing cost-effectiveness analyzes are needed.

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

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

Better Functional Outcome and Pain Relief in the Far-Lateral-Outside-in Percutaneous Endoscopic Transforaminal Discectomy

Background

Even though percutaneous endoscopic transforaminal discectomy (PETD) has been widely used for the surgical treatment of lumbar herniated disc, there are only a few studies directly comparing the clinical outcomes between microdiscectomy (MD) and PETD. Therefore, further studies are needed in order to compare the clinical outcomes between PETD and MD on a single level more thoroughly.

Methods

We proposed a far-lateral-outside-in technique for PETD to get an entry point without complex planning and facet violation. From September 2017 to September 2019, a total of 155 patients (69 with PETD and 86 with MD) were enrolled for this retrospective study, with the inclusion criteria: single level between L2 and S1, clinical sciatica for at least 6 weeks, and failed attempts with non-surgical treatments. Patients were excluded due to cauda equina syndrome, progressive neurologic deficits, history of lumbar spinal surgery, endplate modic changes, severe disc degeneration and less than 24 months of follow-up.

Results

PETD showed significantly shorter surgery time and less intraoperative blood loss compared to MD. The difference between PETD and MD in VAS back pain (but not VAS leg pain) at follow-up time was significant. The ODI improvement in the follow-up time of 6 months between the 2 groups showed a significant difference (PETD: 31.23±6.59, MD: 39.85±7.81, p < 0.001). MD had a significantly higher chance of postoperative wound infection and poor healing, while PETD was more likely to have recurrence of the herniated disc.

Conclusion

MD has been the gold standard procedure for LDH. However, with the advanced endoscopic technology and surgical technique, PETD has emerged as an alternative method due to higher functional outcome and less wound problems.

Comparison of the Clinical Outcomes of Full-Endoscopic Visualized Foraminoplasty and Discectomy Versus Microdiscectomy for Lumbar Disc Herniation

OBJECTIVE

This retrospective case-control study aimed to evaluate and compare the clinical outcomes of full-endoscopic visualized foraminoplasty and discectomy (FEVFD) with microdiscectomy (MD) for lumbar disc herniation (LDH).

METHODS

Data from 198 patients who presented with LDH between January 2016 and December 2017 treated by either FEVFD or MD were retrospectively analyzed. The inclusion criteria were single-level LDH, unilateral radiating leg pain with or without positive Lasegue's sign, and failure of standard conservative treatment for at least 12 weeks. The patients were categorized into an FEVFD group (n = 102) or an MD group (n = 96), according to the surgical procedure performed. Operative time, time in bed after surgery, postoperative hospitalization time, complications, and reoperations were recorded. Visual analog scales (VAS) for leg and back pain, Oswestry Disability index (ODI), 36-Item Short-Form Health Survey physical function (SF36-PF), and bodily pain (SF36-BP) scores were assessed and compared between the two groups.

RESULTS

The demographic data and baseline characteristics of the two groups were not significantly different. Operative time for the FEVFD group (73.82 ± 20.73 min) was longer than that for the MD group (64.74 ± 17.37 min) (P = 0.003), and fluoroscopy time for the FEVFD group (1.71 ± 0.58s) was longer than that for the MD group (1.30 ± 0.33s) (P < 0.001). However, time in bed experienced in the FEVFD group (8.51 ± 2.10 h) was less than that in the MD group (9.24 ± 2.01 h) (P = 0.014), and postoperative hospitalization time experienced in the FEVFD group (2.89 ± 0.83d) was also shorter than that in the MD group (4.94 ± 1.35d) (P < 0.001). All patients completed 24 months of follow-up. Postoperative scores at each follow-up for the VAS for leg and back pain, ODI, SF36-PF, and SF36-BP all improved significantly for both groups, as compared to the preoperative data (P < 0.05). The mean preoperative and postoperative scores for the VAS for leg and back pain, ODI, SF36-PF, and SF36-BP were not significantly different between the two groups. According to the modified MacNab criteria, the outcomes of the procedures were rated as excellent or good by 92.16% and 93.75% of the patients in the FEVFD and MD groups, respectively. One patient suffered a nerve root injury during the discectomy, one patient suffered from a dural tear, and two patients suffered from a residual herniation in the FEVFD group. One patient in the MD group suffered from poor wound healing. Moreover, recurrence happened in two cases in the FEVFD group, and in one case in the MD group.

CONCLUSION

FEVFD and MD are both reliable techniques for the treatment of symptomatic LDH. FEVFD resulted in a more rapid recovery and equivalent clinical outcomes after 24 months of follow-up.

Original Designed Uniportal-Bichannel Spinal Endoscopic System (UBiSES) for Foraminoplasty in Percutaneous Endoscopic Transforaminal Discectomy

OBJECTIVE

The study introduced uniportal-bichannel spinal endoscopic system (UBiSES) and explored the feasibility of applying UBiSES to conduct lumbar foraminoplasty in percutaneous endoscopic transforaminal discectomy (PETD).

METHODS

This is a cohort study. 36 patients confirmed as L5/S1 lumbar disc herniation (LDH) in our hospital from March, 2019 to November, 2019 were enrolled. 36 patients were divided into two groups named the UBiSES group (n = 18, male: female = 8:10) and the TESSYS group (n = 18, male: female = 10:8). The average age of the UBiSES group and the TESSYS group were 40.94 ± 12.39 years old and 39.78 ± 13.02 years old respectively. PETD via uniportal-bichannel foraminoplasty assisted by UBiSES was adopted on the UBiSES group while PETD via conventional foraminoplasty was performed on the TESSYS group. One experienced surgeon with more than 4000 cases of lumbar surgery performed PETD on all patients. The demographic data, the duration of working cannula placement (minutes), decompression time (minutes), radiation exposure time (seconds), complications, Visual Analogue Scale (VAS), Oswestry Disability Index (ODI) scores and modified MacNab criteria were recorded and analyzed. The magnetic resonance imaging (MRI) and computed tomography (CT) were conducted to evaluate the radiographic improvement.

RESULTS

PETD via lumbar foraminoplasty was successfully performed in all cases. The follow-up points were 3 months, 6 months, and 12 months. The average follow-up period of all patients was 15.78 ± 2.29 months. There was no statistic difference in age (P = 0.81), sex (P = 0.51) and follow-up (P = 0.14) between two groups. The duration of working cannula placement was 19.08 ± 2.30 min in the UBiSES group and 24.90 ± 4.71 min in the TESSYS group and there was significant difference between two groups (P < 0.05). There was no statistic difference in decompression time between the UBiSES group (44.18 ± 5.70 min) and the TESSYS group (47.46 ± 5.96 min) (P = 1.70). The radiation exposure time was 28.00 ± 4.70 s in the UBiSES group and 40.50 ± 5.73 s in the TESSYS group respectively, and has significant difference between two groups (P < 0.05). Furthermore, there was significant different in the duration of working cannula placement and radiation exposure time in male or female between the UBiSES group and the TESSYS group (P < 0.05). For male or female, no difference observed in decompression time and follow-up period between two groups. Postoperative VAS of low back and leg at every follow-up point (1 day, 3 months, 6 months, 12 months) was improved significantly in both groups compared with their preoperative VAS (P < 0.05). The postoperative ODI (3 months, 6 months, 12 months) has decreased significantly in both the UBiSES group and the TESSYS group compared with their preoperative ODI (P < 0.05). 94.44% patients received an excellent or good recovery in the UBiSES group and 88.89% for the TESSYS group. There was no poor result reported in both groups. The radiographic images showed satisfactory foraminoplasty and sufficient decompression of nerve in both groups. No postoperative complications were observed during follow-ups in the UBiSES group. Two patients in the TESSYS group experienced postoperative dysesthesia and the symptom was disappeared in 5 days and 7 days respectively with dexamethasone and neurotrophic drugs treatment.

CONCLUSIONS

The original designed UBiSES could effectively and safely enlarge the foramen with an extensive surgical view and space under full-time and real-time visualization and get satisfactory efficacy.

An alternative approach for lumbar transforaminal epidural steroid injection-Far lateral approach

INTRODUCTION

Transforaminal epidural steroid injection (TFESI) is one of the nonoperative interventions for lower back pain. In this study, we presented an alternative approach for TFESI, far lateral lateral recess TFESI (FLLR TFESI), which is targeted on lateral recess and anterior epidural space in patients with degenerative lumbar spondylosis-related radiculopathy.

TECHNIQUE

Under fluoroscopy, needle entry site and pathway are drawn according to the spinal anatomy. The needle is advanced toward the lateral recess and the needle tip is placed medially to the medial border of the pedicle under anteroposterior view and posteriorly to the posterior border of the upper endplate under lateral view. After checking optimal contrast spread, steroids and local anesthetics are injected.

CASE ILLUSTRATION

An 86-year-old woman who suffered from lower back pain with radiculopathy received interventional treatment. Comparing the "traditional" supraneural approach with the FLLR approach, the difference in contrast enhancement to lateral recess is clearly shown.

DISCUSSION

Compared to the pre-existing approaches, the FLLR approach may provide better ventral epidural and lateral recess enhancement. Furthermore, with the advanced needle tip, the injectate may enhance not only the at-level nerve root but also the nerve root of adjacent level during their existence in a single injection. With blunt needle usage, no nerve root injury or dura puncture was noted so far.

CONCLUSION

FLLR TFESI is a modified fluoroscopic technique targeted on lateral recess and anterior epidural space. However, subsequent trials are needed to confirm its efficacy in pain reduction and the rate of complications.

Comparison of post-operative wound pain between interlaminar and transforaminal endoscopic spine surgery: which is superior?

STUDY DESIGN

Prospective cohort study PURPOSE: The objective is to compare post-operative wound pain in patients treated by endoscopic surgery between interlaminar and transforaminal approach at lumbar region.

OVERVIEW OF LITERATURE

There are two common approaches for endoscopic lumbar spine surgery, interlaminar and transforaminal approach. The wound size of these two approaches is about the same. However, post-operative wound pain may differ according to the entrance area.

METHODS

We conducted a prospectively cohort study including all patients underwent full endoscopic lumbar spine surgery by single surgeon between January 2016 to October 2019. Wound pain using visual analog scale (VAS) at post-operative day 1 and day 14 were collected. VAS back pain, VAS leg pain, Oswestry Disability Index (ODI), modified McNab criteria and complications were also collected.

RESULTS

There were 313 patients included in the study. There was no significant difference in VAS wound pain between interlaminar and transforaminal group. Interestingly, subgroup analysis in interlaminar group found statistically significant higher VAS for wound pain at post-operative day 1 when significant bone resection was done by power burr. VAS back-leg pain and ODI have improved significantly between pre-operative and last follow up in both approaches.

CONCLUSIONS

Wound pain from endoscopic spine surgery is minimal. This study found no difference in wound pain between endoscopic interlaminar and transforaminal approach. Both approaches show favorable clinical outcomes with few serious complications rate. Further study with long term follow up is needed.

The 100 Most-Cited Publications in Endoscopic Spine Surgery Research

STUDY DESIGN

A bibliometric review of the literature.

OBJECTIVE

Our objective was to identify and analyze the 100 most-cited publications in the field of endoscopic spine surgery (ESS).

METHODS

In order to determine the top cited 100 articles, a 3-step approach was employed. First, the 100 most-cited ESS studies were identified using the key phrase "endoscopic spine surgery." Then, 8 keywords were identified from the 100 studies of step 1 were used to conduct a second round searching in all databases of the Web of Science. Finally, when the results of the first and second steps were overlapped, duplicated studies were removed. The 100 top-cited articles were used for further analysis.

RESULTS

The citation number of the top 100 most-cited articles ranged from 44 to 236 with a mean value of 84.4. The most productive periods were from 2001 to 2010. The majority of publications came from Spine and Neurosurgery, where Spine holds the largest number of 35 articles, followed by Neurosurgery with 13 articles. Overall, 10 countries contributed to the 100 articles, with the most productive country being the United States, followed by Germany and Korea.

CONCLUSION

This bibliometric study is meant to produce a list of intellectual milestones in the field of ESS. This article's identification of the most influential articles in the field of ESS gives us a unique and comprehensive insight into the development of ESS in the past several decades.

Follow-up results of microendoscopic discectomy compared to day surgery using percutaneous endoscopic lumbar discectomy for the treatment of lumbar disc herniation

BACKGROUND

Percutaneous endoscopic lumbar discectomy (PELD) is satisfactory for hospitalized patients with lumbar disc herniation (LDH). Currently, only a few studies have reported about the day surgery patients undergoing PELD.

METHODS

A total of 267 patients with LDH underwent PELD during day surgery and were followed up for at least 3 years. Clinical outcomes were assessed using the visual analog scale (VAS) for leg and lower back pain (VAS-B and VAS-L, respectively) and the Oswestry disability index (ODI). The radiological outcomes, such as lumbar lordosis (LL), sacral slope (SS), the disc-height ratio, and disc instability, were recorded and compared. The clinical effects between patients treated by PELD during day surgery and microendoscopic discectomy (MED) for contemporaneous hospitalized 116 patients with LDH were compared.

RESULTS

Patients treated by PELD had lower blood loss and shorter hospital stay (P <  0.001) compared to those treated by MED. VAS-L, VAS-B, and ODI decreased significantly after PELD than before the operation and 3 years postoperatively. The postoperative VAS-B in the PELD group was significantly decreased than in the MED group (P = 0.001). The complications rate was 9.4% in the PELD group and 12.1% in the MED group (P = 0.471). The 1-year postoperative recurrence rate in the PELD group was much higher than that in MED group (P = 0.042). The postoperative LL and SS in the PELD group improved significantly compared to the values in the MED group (P <  0.001). According to the disc-height ratio at 3-year follow-up, a significant height loss was observed in the MED group than in the PELD group (P = 0.014).

CONCLUSIONS

Although the 1-year postoperative recurrence rate was relatively high, the day surgery for LDH undergoing PELD had advantages in terms of less blood loss intraoperatively, short hospital stay, efficacy for back pain, and efficiency to maintain lumbar physiological curvature.

Early Clinical Evaluation of Percutaneous Full-endoscopic Transforaminal Lumbar Interbody Fusion with Pedicle Screw Insertion for Treating Degenerative Lumbar Spinal Stenosis

Objective

To compare the clinical efficacy of percutaneous full‐endoscopic transforaminal lumbar interbody fusion (Endo‐TLIF) with percutaneous pedicle screws (PPSs) performed by using a visualization system with that of minimally invasive transforaminal lumbar interbody fusion (MIS‐TLIF) for the treatment of degenerative lumbar spinal stenosis (LSS).

Methods

From June 2017 to May 2018, the data of a total of 78 patients who met the selection criteria were retrospectively reviewed and were divided into the Endo‐TLIF group (40 cases) and the MIS‐TLIF group (38 cases) according to the surgical method used. The visual analog scale (VAS) and the Japanese Orthopaedic Association (JOA) scale were administered preoperatively and at the 1‐week, 3‐month, and 1–2‐year follow‐ups. The fusion rate and major complications, including revision, were also recorded.

Results

All the patients were followed up for 24 to 34 months, with an average follow‐up of 30.7 months. The intraoperative blood loss and length of hospital stay for the Endo‐TLIF group (60.56 ± 0.36 mL, 8.12 ± 0.92 days, respectively) were statistically significantly lower than those for the MIS‐TLIF group (65.47 ± 0.91 mL, 9.66 ± 1.34 days, respectively) (P < 0.05). The VAS and JOA scores of the patients in the two groups at postoperative 1 week, 3 months, 1 year, 2 years (Endo‐TLIF VAS: 4.16 ± 0.92, 3.72 ± 1.54, 1.32 ± 0.45, 1.29 ± 0.34; JOA:16.71 ± 0.99, 19.86 ± 0.24, 24.91 ± 0.97, 25.88 ± 0.52; MIS‐TLIF VAS: 4.17 ± 1.41, 2.98 ± 0.91, 1.54 ± 0.32, 1.33 ± 0.18; JOA: 16.67 ± 0.67, 19.58 ± 0.65, 25.33 ± 0.73, 25.69 ± 0.33) were statistically significantly improved from the preoperative scores (Endo‐TLIF: 8.45 ± 1.44, 14.36 ± 0.56; MIS‐TLIF: 8.11 ± 0.93, 14.45 ± 0.34, respectively) (P < 0.01). The VAS and JOA scores of the Endo‐TLIF group were statistically significantly better than those of the MIS‐TLIF group at 3 months and 1 year after surgery (P < 0.05). There were no statistically significant differences in the scores between the two groups at any of the other time points (P > 0.05). There was no significant difference in the intervertebral altitude between the two groups at the 3‐month (11.36 ± 0.23, 11.21 ± 0.42, respectively) or final follow‐up (10.88 ± 0.64, 10.81 ± 0.39, respectively) (P > 0.05). Dural tears, cerebrospinal fluid leakage, infection, and neurologic injury did not occur. Both groups showed good intervertebral fusion at the last follow‐up. The intervertebral fusion rate was 97.5% (39/40) in the Endo‐TLIF group and 94.7% (36/38) in the MIS‐TLIF group, with no statistically significant difference between the two groups (χ² = 0.118, P = 0.731). At the final follow‐up, the modified MacNab's criteria were 92.5% and 89.5% between the two groups.

Conclusion

Endo‐TLIF with percutaneous pedicle screws (PPS) performed by using a visualization system for lumbar degenerative disease may be regarded as an efficient alternative surgery for degenerative lumbar spinal stenosis. It is a safe and minimally invasive way to perform this surgery and has shown satisfactory clinical outcomes.

Risk Factors for Recurrent L4-5 Disc Herniation After Percutaneous Endoscopic Transforaminal Discectomy: A Retrospective Analysis of 654 Cases

Background

Percutaneous endoscopic lumbar discectomy (PELD) is an increasingly applied minimally invasive procedure that has several advantages in the treatment of lumbar disc herniation (LDH). However, recurrent LDH (rLDH) has become a concerning postoperative complication. It remains difficult to establish a consensus and draw reliable conclusions regarding the risk factors for rLDH.

Purpose

This retrospective study aimed to investigate the risk factors associated with rLDH at the L4-5 level after percutaneous endoscopic transforaminal discectomy (PETD).

Methods

A total of 654 patients who underwent the PETD procedure at the L4-5 level from October 2013 to January 2020 were divided into a recurrence (R) group (n=46) and a nonrecurrence (N) group (n=608). Demographic and clinical data and imaging parameters were collected and analyzed using univariate and multiple regression analyses.

Results

The current study found a 7% rate of rLDH at the L4/5 level after successful PETD. Univariate analysis showed that older age, high BMI, diabetes mellitus history, smoking, large physical load intensity, moderate disc degeneration, small muscle-disc ratio (M/D), more fat infiltration, large sagittal range of motion (sROM), scoliosis, small disc height index (DHI), small intervertebral space angle (ISA), and small lumbar lordosis (LL) were potential risk factors (P < 0.10) for LDH recurrence after PETD at the L4-5 level. Multivariate analysis suggested that high BMI, large physical load intensity, moderate disc degeneration, small M/D, more fat infiltration, large sROM, small ISA, and small LL were independent significant risk factors for recurrence of LDH after PETD.

Conclusion

Consideration of disc degeneration, M/D, fat infiltration of the paravertebral muscles, sROM, ISA, LL, BMI, and physical load intensity prior to surgical intervention may contribute to the prevention of rLDH following PETD and lead to a more satisfactory operative outcome and the development of a reasonable rehabilitation program after discharge.

Management for lumbar spinal stenosis: A network meta-analysis and systematic review

BACKGROUND

Conventional paired meta-analyses have shown inconsistent results regarding the safety and efficacy of different interventions.

OBJECTIVE

To perform a network meta-analysis (NMA) and systematic review based on randomized controlled trials (RCTs) evaluating the efficacies of different interventions for lumbar spinal stenosis (LSS).

METHODS

We searched PubMed, Embase, Cochrane Library, Web of Science, and major scientific websites from inception to October 10, 2019, for randomized controlled trials comparing the nine most commonly used interventions for LSS. The main outcomes were disability and pain intensity. The PROSPERO number was CRD42020154247.

RESULTS

First, laminotomy was better in improving patients' short- and long-term dysfunction (probability 49% and 25%, respectively). Second, decompression, decompression plus fusion, endoscopic decompression, interspinous process spacer device implantation, laminectomy, laminotomy and minimally invasive decompression were significantly more efficacious in relieving pain than non-surgical interventions (mean difference in the short-term -21.82, -22.00, -16.68, -17.47, -17.75, -17.61 and -18.86; in the long-term -37.14, -34.04, -34.07, -39.79, -36.14, -32.75 and -39.14, respectively). Third, endoscopic decompression had a lower complication rate (probability 51%). In addition, laminotomy had a lower reoperation rate (probability 45%). Fourth, decompression plus fusion resulted in more blood loss than any other surgical intervention (probability 96%). Finally, endoscopic decompression had the shortest hospitalization time (probability 96%).

CONCLUSIONS

There were no significant differences among the different interventions in improving patient function. Surgical interventions were associated with better pain relief but a higher incidence of complications. Decompression plus fusion is not necessary for patients. In addition, endoscopic decompression as a novel and less invasive surgical approach may be a good choice for LSS patients.

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.

Necessity of routinely performing foraminoplasty during percutaneous endoscopic transforaminal discectomy (PETD) for lumbar disc herniation

OBJECTIVE

To assess the role of foraminoplasty during percutaneous endoscopic transforaminal discectomy (PETD) and compared the 2-year clinical results of patients underwent PETD w/o foraminoplasty.

METHODS

A total of 412 patients, who underwent PETD at L3-S1 by the same surgical group, were enrolled in this study. The MRI was used to determine the height (H1) and width (W1) of the intervertebral foramen of L3-S1, the distance between the exiting nerve root and the upper edge of the lower vertebral pedicle (H2), and the distance (W2) between the point with 3 mm to the ventral side of the intervertebral space and superior articular process. The intervertebral foramen widths in the flexion (W3) and extension positions (W4) were also measured. A VAS of low back pain (LBP) and leg pain, ODI and JOA scores of LBP were used to assess the clinical results.

RESULTS

Intraoperative verification showed that 347 cases (group A) did not need foraminoplasty, while the other 65 patients (group B) needed foraminoplasty, including 31 at L4-5 and 34 at L5-S1. The H1 and H2 of L3-S1 were reduced gradually without significant difference between two groups. The W1, W2, W3 and W4 were higher in group A (p < 0.05). The W3 was higher than W4 in both groups (p < 0.05). At 2-year follow-up, there was no significant difference of ODI and JOA score between two groups (p > 0.05). The VAS score of LBP was better in group A (p < 0.05).

CONCLUSIONS

Most of PETD procedure at L3-S1 levels could reach the therapeutic target without foraminoplasty. Due to anatomic characteristics of L5-S1, the foraminoplasty rate was much higher at L5-S1.

Technical Considerations of the Transforaminal Approach for Lumbar Disk Herniation

Transforaminal full endoscopic lumbar diskectomy (TELD) is a typical minimally invasive surgery, with the associated benefit of decreased possibility of anatomic structural injury, and is an effective alternative to open diskectomy. Among the various endoscopic spinal surgical techniques currently available, TELD is the most basic and traditional surgery that can be performed through the transforaminal route; it has been used for >30 years. Recently, with the advancements in surgical techniques, TELD has been successfully performed for patients with lumbar disk herniation of different types. However, beginner surgeons are unfamiliar with the anatomy of transforaminal endoscopic surgery and this surgery has a steep learning curve to date. If not well prepared, operators may experience complications that require reoperation in the early stages. These complications may include symptomatic incomplete decompression, exiting nerve root injury, dural tearing, and rarely, hematoma, infection, and visceral injury. Here, we propose several technical guidelines for TELD to increase the possibility of successful lumbar diskectomy and to reduce the incidence of complications. The first step is the accurate anatomic understanding of Kambin triangle and determining the appropriate endoscopic access angle, depending on the type of disk herniation. The second step is to determine a safe and easily accessible entry point and then landing and docking the working sleeve as close to the target as possible without causing exiting nerve root injury. The third step is complete decompression of the symptomatic nerve with free mobilization of the neural tissue. The final step involves performing foraminoplasty using an advanced technique to overcome the limitations associated with TELD in difficult cases.

What Is the Ideal Entry Point for Transforaminal Endoscopic Lumbar Discectomy?

OBJECTIVE

The method of approach during transforaminal endoscopic lumbar discectomy (TELD) has been the subject of repeated study. However, the ideal entry point during TELD has not been studied in detail. Therefore, this study investigated the ideal entry point for avoiding complications using computed tomography (CT) scans obtained from patients in the prone position.

METHODS

Using CT scans obtained from patients in the prone position, we checked for retroperitoneal or visceral violations and measured the angles of approach with five conventional approach lines drawn on axial CT scans at each disc space level (L2-3, L3-4, and L4-5). We also determined the ideal entry point distance and approach angles for avoiding retroperitoneal or visceral violations. Correlation analysis was performed to identify the patient characteristics related to the ideal entry point properties.

RESULTS

We found that the far lateral approach at the L2-3 level resulted in high rates of visceral violation. However, rates of visceral violation at the L3-4 and L4-5 levels were remarkably low or absent. The ideal angles of approach decreased moving caudally along the spine, and the ideal entry point distances increased moving caudally along the spine. Weight, body mass index (BMI), and the depth of the posterior vertebral line from the skin were positively associated with the distance of the ideal entry point from the midline.

CONCLUSION

We reviewed the risk of the extreme lateral approach by analyzing rates of retroperitoneal and visceral violations during well-known methods of approach. We suggested an ideal entry point at each level of the lumbar spine and found a positive correlation between the distance of the entry point to the midline and patient characteristics such as BMI, weight, and the depth of the posterior vertebral line from the skin.

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.

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 Surgery: Outside-In Technique

Transforaminal endoscopic lumbar discectomy (TELD) with the outside-in technique can be applied to nearly all cases of lumbar disc herniation (LDH), and transpedicular endoscopic lumbar discectomy can be used to treat highly migrated LDHs. The purpose of this study was to outline these 2 outside-in surgical techniques and to present their clinical outcomes. Between January 2018 and January 2019, a total of 137 patients underwent either transforaminal or transpedicular endoscopic lumbar discectomy. We performed TELD in 124 patients and transpedicular endoscopic lumbar discectomy in 13 cases. All surgical procedures were performed under conscious sedation. The patients’ mean age was 51.3 years; 51 were women and 86 were men. The overall disc recurrence rate was 5.12%. Visual analogue scale scores decreased significantly in both groups. According to the MacNab criteria, good and excellent results were obtained in 92.74% of patients after transforaminal and in 92.30% of patients after transpedicular endoscopic LDH treatment. The results suggest that TELD with the outside-in technique can be effective for the treatment of most cases of LDH. Transpedicular endoscopic lumbar discectomy can be considered as an alternative treatment for highly migrated LDH.

Cauda Equina Syndrome: A Review of 15 Patients Who Underwent Percutaneous Transforaminal Endoscopic Lumbar Discectomy (PTELD) Under Local Anaesthesia

INTRODUCTION

To analyse the results of Cauda Equina Syndrome (CES) operated by Percutaneous Transforaminal Endoscopic Lumbar Discectomy (PTELD).

MATERIAL AND METHODS

The study is a retrospective series of 15 patients operated by PTELD. Bladder dysfunction was classified as incomplete CES (CESI) and complete CES retention (CESR). Bladder / motor recovery rate and its timing, Oswestry Disability Index (ODI), Visual Analogue Score (VAS), patient satisfaction index, and sexual dysfunction were used to measure the outcome objectively. Additionally, in CESR patients, post-void residual (PVR) urine was measured by sonography. Complications and technical problems were noted.

RESULTS

There were ten patients of CESI and five patients of CESR. The average follow-up was 20.33(12.05) months. Bladder symptoms recovery was 100%, and motor recovery was 80%. VAS for back pain recovered to 0.53(0.52) from 8(2.39). VAS for leg pain recovered to 0.13(0.35) from 9.20(1.32). ODI improved to 6.07(2.85) from 77.52(13.20). The time to the recovery of bladder function was 1.47(1.55) days. All CESR patient's abnormal PVR urine was normalised at five weeks post-operative. No complications were reported. However, five technical executional problems occurred.

CONCLUSION

PTELD can be considered for CES treatment due to its substantial and quick recovery advantages. However, more evidence support is needed to make it a practice recommendation.

Evolution of endoscopic transforaminal lumbar approach for degenerative lumbar disease

Endoscopic spine surgery has evolved dramatically in last 30 years; with the development of new improved endoscopic optics and instrumentation limitation of endoscopic spine surgery has significantly reduced. The transforaminal approach has been limited in its indications due to its optimized approach and obstacles of bony or neural structures. As the initial transforaminal approach is based on the inside out technique, there were many limitations on the indications. Outside-in approach has been developed to address these limitations. However, the outside-in approach was not free from anatomical obstacles. The mobile outside-in approach technique has advantage of both inside-out and outside-in technique. It is equally safe as inside-out technique and provides an easy handling of structures, while it is equally versatile as outside-in technique in managing different types of disc prolapse such as central, paracentral, foraminal, far lateral, and up and down migration, and in high-canal compromise cases. The mobile outside in technique, however, demands a longer learning curve and beginners need to be patient while learning the technique.

Three-dimensional architecture of the neurovascular and adipose zones of the upper and lower lumbar intervertebral foramina: an epoxy sheet plastination study

OBJECTIVE

Kambin's triangle and the safe triangle are common posterolateral approaches for lumbar transforaminal endoscopic surgery and epidural injection. To date, no consensus has been reached on the optimal transforaminal approach, in particular its underlying anatomical mechanism. The aim of this study was to investigate the 3D architecture of the neurovascular and adipose zones in the upper and lower lumbar intervertebral foramina (IVFs).

METHODS

Using the epoxy sheet plastination technology, 22 cadaveric lumbar spines (12 female and 10 male, age range 46-89 years) were prepared as a series of transverse (11 sets), sagittal (8 sets), and coronal (3 sets) slices with a thickness of 0.25 mm (6 sets) or 2.5 mm (16 sets). The high-resolution images of the slices were scanned and analyzed. The height, area, and volume of 30 IVFs from T12-L1 to L4-5 were estimated and compared. This study was performed in accord with the authors' institutional ethical guidelines and approved by the institutional ethics committees.

RESULTS

The findings were as follows. 1) The 3D boundaries of the lumbar IVF and its subdivisions were precisely defined. 2) The 3D configuration of the neurovascular and adipose zones was different between the upper and lower lumbar IVFs; zoning in the upper lumbar IVFs was much more complex than that in the lower lumbar IVFs. 3) In general, the infraneural adipose zone gradually tapered and rotated from the inferoposterolateral aspect to the superoanteromedial aspect. 4) The average height, area, and volume of the IVF gradually increased from the upper to the lower lumbar spine. Within a lumbar IVF, the volumes below and above the inferior border of the dorsal root ganglia were similar.

CONCLUSIONS

This study highlights differences of fine 3D architecture of neurovascular and adipose tissues between the upper and lower lumbar IVFs, with related effects on the transforaminal approaches. The findings may contribute to optimization of the surgical approaches to and through the IVF at different lumbar spinal levels and also may help to shorten the learning curve for the transforminal techniques.

AOSpine Consensus Paper on Nomenclature for Working-Channel Endoscopic Spinal Procedures

STUDY DESIGN

International consensus paper on a unified nomenclature for full-endoscopic spine surgery.

OBJECTIVES

Minimally invasive endoscopic spinal procedures have undergone rapid development during the past decade. Evolution of working-channel endoscopes and surgical instruments as well as innovation in surgical techniques have expanded the types of spinal pathology that can be addressed. However, there is in the literature a heterogeneous nomenclature defining approach corridors and procedures, and this lack of common language has hampered communication between endoscopic spine surgeons, patients, hospitals, and insurance providers.

METHODS

The current report summarizes the nomenclature reported for working-channel endoscopic procedures that address cervical, thoracic, and lumbar spinal pathology.

RESULTS

We propose a uniform system that defines the working-channel endoscope (full-endoscopic), approach corridor (anterior, posterior, interlaminar, transforaminal), spinal segment (cervical, thoracic, lumbar), and procedure performed (eg, discectomy, foraminotomy). We suggest the following nomenclature for the most common full-endoscopic procedures: posterior endoscopic cervical foraminotomy (PECF), transforaminal endoscopic thoracic discectomy (TETD), transforaminal endoscopic lumbar discectomy (TELD), transforaminal lumbar foraminotomy (TELF), interlaminar endoscopic lumbar discectomy (IELD), interlaminar endoscopic lateral recess decompression (IE-LRD), and lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD).

CONCLUSIONS

We believe that it is critical to delineate a consensus nomenclature to facilitate uniformity of working-channel endoscopic procedures within academic scholarship. This will hopefully facilitate development, standardization of procedures, teaching, and widespread acceptance of full-endoscopic spinal procedures.

Foraminoplasty affects the clinical outcomes of discectomy during percutaneous transforaminal endoscopy: a two-year follow-up retrospective study on 64 patients

Objective: The aim of this study was to assess the significance of how the degree of injury of the facet joint affects clinical outcomes in foraminoplasty.Methods: We retrospectively enrolled 64 patients treated with percutaneous endoscopic transforaminal discectomy with foraminoplasty (PETDF) from January of 2015 to December of 2016. The patients were divided into two groups depending on whether the articular surface of the facet joint was damaged. Preoperative, perioperative, demographic data, and radiographic parameters for these two groups were extracted and compared.Results: There were no significant differences between the two groups in terms of the duration of operation (p = 0.331), intraoperative blood loss volume (p = 0.631), the weight of disc (p = 0.274) or cut bone (p = 0.526). There were no significant differences between the two groups for VAS or ODI at the same time point (p > 0.05). There were significant differences in the VAS scores of low-back pain at 24 h and 24 months after surgery in the injured group. There were significant differences in ISH, ISA, rate of lumbar instability, recurrent herniation, and Macnab scores between the two groups at 24 months after surgery (p < 0.05). The regression equation between ISA and ISH was Y = 4.237 + 0.565x (where Y denotes an increase of ISA; X, reduction of ISH; F = 6.219, p = 0.015). The Poisson ratio was 0.363 (p = 0.003).Conclusions: PETDF is effective and safe for the treatment of lumbar disc herniation. However, when foraminoplasty destroys the articular surface of the facet joint, there may be increases in lumbar instability and recurrence rate post-operation.

Learning Curve and Early Results of Interlaminar and Transforaminal Full-Endoscopic Resection of Lumbar Disc Herniations

Background

Full-endoscopic spinal surgery is an evolving technique. A laborious learning phase is inevitable due to the complexity of the orientation and instrumentation. The goal of the present study is to evaluate a single surgeon’s learning curve and early outcomes in full-endoscopic resection of lumbar disc herniations.

Methods

This was a prospective non-controlled single-surgeon cohort study. In 54 patients with 57 herniations, 41 interlaminar and 16 transforaminal resections were performed. Surgery time, severity of adhesive process in the spinal canal, complication rates and clinical outcomes (VAS, ODI, custom questionnaire, recurrence and re-operation rate) were assessed.

Results

In the interlaminar group, operative time has decreased from 60 ± 20 min in the first 20 operations to 45 ± 14 min in the following 17 (p=0.023). In the transforaminal group, operative time has decreased from 60 ± 16 min in the first 7 operations to 41 ± 12 min in following 9 (p=0.023). Severe adhesive process in spinal canal was associated with duration of symptoms greater than 2 years, longer surgery and higher risk of surgical complications. Four recurrent disc herniations were re-operated using full-endoscopic technique. VAS, ODI and pain medications significantly decreased in both groups and in re-operated patients.

Conclusion

The plateau of the learning curve and good short-term clinical results of full-endoscopic interlaminar and transforaminal surgery may be achieved after twenty operations, given extensive previous experience in microsurgery. Risk of complications at the learning phase may be decreased by excluding the patients with symptoms lasting over two years.

Percutaneous Endoscopic Lumbar Discectomy Versus Microdiscectomy for the Treatment of Lumbar Disc Herniation: Pain, Disability, and Complication Rate-A Randomized Clinical Trial

Purpose

The objective was to compare the traditional microdiscectomy with percutaneous endoscopic lumbar discectomy for the treatment of disc herniations regarding pain, disability, and complications.

Methods

Randomized clinical trial with 47 patients with disc herniations treated with 2 different surgical techniques: traditional microdiscectomy or percutaneous endoscopic lumbar discectomy. Forty-seven patients were divided into 2 groups and monitored for 12 months. Irradiated and low back pain were evaluated with the visual analog scale. Surgery complications were recorded.

Results

After surgery, the sciatica and disability improved significantly but without significant differences between the groups. Improvements in back pain were significant until the third month. There were no statistical differences between groups regarding recurrence, infection, and the need for reoperation.

Conclusions

Endoscopic discectomy results are similar to those of conventional microdiscectomy regarding pain and disability improvement. Postoperative lumbar pain is less intense with endoscopic discectomy than conventional microdiscectomy only during the first 3 months. Endoscopic discectomy is a safe and efficient alternative to microdiscectomy.

Clinical Trials

Trial protocol registration number: RBR-5symrd (http://www.ensaiosclinicos.gov.br).

Relationship of the Exiting Nerve Root and Superior Articular Process in Kambin's Triangle: Assessment of Lumbar Anatomy Using Cadavers and Computed Tomography Imaging

BACKGROUND

Percutaneous transforaminal endoscopic diskectomy has been a major treatment for lumbar disk herniation. However, damage to exiting nerve roots is one of the most severe complications in this surgery. In this paper, the relationship of the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen was assessed using cadavers and computed tomography (CT) imaging.

METHODS

The anatomic relationship between the exiting nerve root and the superior articular process in Kambin's triangle of the intervertebral foramen was investigated on 6 cadavers. The distance between the exiting nerve and the superior articular process of the L1-2 to L5-S1 intervertebral foramina was measured using multiplane reconstruction.

RESULTS

The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle was quite narrow both in cadaver and CT imaging study. The distance of the L5-S1 intervertebral foramen was the greatest, which was no more than 5.77 ± 0.56 mm. The distances increased gradually from the tip to the root, and the distances between the root and the tip were 0.91 ± 0.31 to 1.86 ± 0.57 mm, which took on a trapezoid shape that was relatively narrow at the proximal end and wider at the distal end.

CONCLUSIONS

The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen was exceedingly narrow. It is necessary to perform a foraminoplasty to enlarge the working space and decrease the possibility of injury to the exiting nerve root.