Extraforaminal approach of biportal endoscopic spinal surgery: a new endoscopic technique for transforaminal decompression and discectomy

Outcomes of FETD versus UBE in the treatment of L5S1 foraminal stenosis: A comparative study

Background

The L5S1 level exhibits unique anatomical features compared with other levels. This makes minimally invasive surgery for L5S1 foraminal stenosis (FS) challenging. This study compared the surgical outcomes of full endoscopic transforaminal decompression (FETD) and unilateral biportal endoscopy with the far-lateral approach (UBEFLA) in patients with L5S1FS.

Methods

In this retrospective study, 49 patients with L5S1FS were divided into two groups. Of these, 24 patients underwent FETD, 25 patients underwent UBEFLA. The study assessed demographic data, leg pain visual analog scale (VAS) score, back pain VAS score, Oswestry Disability Index (ODI), modified MacNab outcome scale, and radiographic parameters including postoperative lateral facet preservation (POLFP).

Results

The Mann-Whitney U test revealed that the UBEFLA group exhibited a higher VAS score for back pain at one week after the operation, whereas the FETD group exhibited a higher leg pain VAS score 6 weeks after the operation. All four undesired MacNab outcomes in the FETD group were attributed to residual leg pain, whereas all five undesired MacNab outcomes in the UBEFLA group were due to recurrent symptoms. Radiographically, the FETD group exhibited greater POLFP.

Conclusions

When L5S1FS is performed, there may be challenges in adequately clearing the foraminal space in FETD. On the other hand, UBEFLA allowed for a more comprehensive clearance. However, this advantage of UBEFLA was associated with spinal instability as a future outcome.

Advances and Challenges of Endoscopic Spine Surgery

The purpose of this paper is to review the data supporting current endoscopic surgical techniques for the spine and the potential challenges and future of the field. The origins of endoscopic spine surgery can be traced back many decades, with many important innovations throughout its development. It can be applied to all levels of the spine, with many robust trials supporting its clinical outcomes. Continued clinical research is needed to explore its expanding indications. Although the limitations of starting an endoscopic program can be justified by its cost effectiveness and positive societal impact, challenges facing its widespread adoption are still present. As more residency and fellowship programs include endoscopy as part of their spine training, it will become more prevalent in hospitals in the United States. Technological advancements in spine surgery will further propel and enhance endoscopic techniques as they become an integral part of a spine surgeon's repertoire.

The Method of Portal Making in Lumbar Unilateral Biportal Endoscopic Surgery with Different Operative Approaches According to the Constant Anatomical Landmarks of the Lumbar Spine: A Review of the Literature

STUDY DESIGN

Review.

OBJECTIVE

Unilateral Biportal Endoscopy (UBE) is a minimally invasive surgery that is gaining recognition and being employed in clinical practice. Nevertheless, the precise method for determining UBE portals' location varies depending on the originator's preferences or the anatomical structure's proximity to the portal positions. Consequently, the relationship among UBE portals' locations is messy. This study aims to elaborate on the specific portal localization and explore the positional association and commonality among different UBE approaches' portals.

METHODS

The following keywords are used to search in the PubMed, Ovid, Web of Science, ScienceDirect, SpringerLink, Scopus, CNKI, and Wanfang database: "Biportal endoscopic spinal surgery", "Two portal endoscopic spinal surgery", "Percutaneous biportal endoscopic decompression", "Unilateral biportal endoscopy", "Irrigation endoscopic discectomy", "UBE" and "BESS".

RESULTS

After screening, 29 pieces of literature are included. The study summarizes different UBE approach portal localizations, categorized by fusion or non-fusion surgery and pathological classification. The study presents an inaugural method for categorizing the lumber into four surgical intervals based on bone landmarks and assigns different UBE approaches to the appropriate intervals based on their characteristics, making the selection of UBE surgical approaches' portal locations more flexible. Additionally, the study provides an overview of the indications, complications, and distinct benefits associated with each interval, further refining the novel UBE portal interval localization method.

CONCLUSION

The study clarifies the interrelationship and commonality between the portals of different UBE approaches and proposes a new UBE portal interval localization method to enhance surgeons' understanding and proficiency in UBE procedures.

Exploring Physical Lumbar Microvascular Geometry Through Endoscopy and Illustrations: Implications for Clinical Interpretation

STUDY DESIGN

Retrospective Study.

OBJECTIVES

Minimally invasive endoscopic spinal surgery is gaining popularity, but our understanding of the lumbar spine's microvascular geometry relies heavily on cadaver studies and textbook illustrations. Additionally, inconsistent nomenclature of vessels in the literature hampers effective communication among surgeons. This study aims to improve the clarity and comprehensibility of the lumbar spinal microvascular geometry under endoscopic view.

METHODS

The study included 400 patients who underwent endoscopic spinal surgery for lumbar spinal canal stenosis and foraminal stenosis. The surgeries were performed by an experienced surgeon using either the interlaminar or transforaminal approach. Endoscopic video recordings were further analyzed to map the microvascular geometry and common bleeding foci. The observed results were cross-referenced with existing literature to reconstruct a comprehensive view of the vascular anatomy.

RESULTS

The transforaminal approach commonly encounters bleeding foci originating from the major branches of the segmental lumbar artery and the emissary veins within the foramen. The interlaminar approach primarily encounters bleeding foci from the muscle vessels in the dorsal lamina, which are believed to be located near the ends of the three main branches. In the intracanal region, epidural vessels form a rotary loop above the disc, which can contribute to most of the bleeding during discectomy.

CONCLUSIONS

This study provides a comprehensive understanding of the microvascular anatomy in the lumbar spine during endoscopic spinal surgery. Recognizing the geometry will help surgeons anticipate and control bleeding, reducing the risk of complications. The findings contribute to the improvement of surgical techniques and patient safety in endoscopic spinal surgery.

Biportal endoscopic paraspinal decompressive foraminotomy for lumbar foraminal stenosis: clinical outcomes and factors influencing unsatisfactory outcomes

BACKGROUND

Lumbar foraminal stenosis (LFS) is an important pathologic entity that causes lumbar radiculopathies. Unrecognized LFS may be associated with surgical failure, and LFS remains challenging to treat surgically. This retrospective cohort study aimed to evaluate the clinical outcomes and prognostic factors of decompressive foraminotomy performed using the biportal endoscopic paraspinal approach for LFS.

METHODS

A total of 102 consecutive patients with single-level unilateral LFS who underwent biportal endoscopic paraspinal decompressive foraminotomy were included. We evaluated the Visual Analogue Scale (VAS) score and the Oswestry Disability Index (ODI) before and after surgery. Demographic, preoperative data, and radiologic parameters, including the coronal root angle (CRA), were investigated. The patients were divided into Group A (satisfaction group) and Group B (unsatisfaction group). Parameters were compared between these two groups to identify the factors influencing unsatisfactory outcomes.

RESULTS

In Group A (78.8% of patients), VAS and ODI scores significantly improved after biportal endoscopic paraspinal decompressive foraminotomy (p < 0.001). However, Group B (21.2% of patients) showed higher incidences of stenosis at the lower lumbar level (p = 0.009), wide segmental lordosis (p = 0.021), and narrow ipsilateral CRA (p = 0.009). In the logistic regression analysis, lower lumbar level (OR = 13.82, 95% CI: 1.33-143.48, p = 0.028) and narrow ipsilateral CRA (OR = 0.92, 95% CI: 0.86-1.00, p = 0.047) were associated with unsatisfactory outcomes.

CONCLUSIONS

Significant improvement in clinical outcomes was observed for a year after biportal endoscopic paraspinal decompressive foraminotomy. However, clinical outcomes were unsatisfactory in 21.2% of patients, and lower lumbar level and narrow ipsilateral CRA were independent risk factors for unsatisfactory outcomes.

Clinical outcomes and complications after biportal endoscopic spine surgery: a comprehensive systematic review and meta-analysis of 3673 cases

PURPOSE

Current literature suggests that biportal spinal endoscopy is safe and effective in treating lumbar spine pathology such as lumbar disc herniation, lumbar stenosis, and degenerative spondylolisthesis. No prior study has investigated the postoperative outcomes or complication profile of the technique as a whole. This study serves as the first comprehensive systematic review and meta-analysis of biportal spinal endoscopy in the lumbar spine.

METHODS

A PubMed literature search provided over 100 studies. 42 papers were reviewed and 3673 cases were identified with average follow-up time of 12.5 months. Preoperative diagnoses consisted of acute disc herniation (1098), lumbar stenosis (2432), and degenerative spondylolisthesis (229). Demographics, operative details, complications, and perioperative outcome and satisfaction scores were analyzed.

RESULTS

Average age was 61.32 years, 48% male. 2402 decompressions, 1056 discectomies, and 261 transforaminal lumbar Interbody fusions (TLIFs) were performed. Surgery was performed on 4376 lumbar levels, with L4-5 being most common(61.3%). 290 total complications occurred, 2.23% durotomies, 1.29% inadequate decompressions, 3.79% epidural hematomas, and < 1% transient nerve root injuries, infections, and iatrogenic instability. Significant improvement in VAS-Back, VAS-Leg, ODI, and Macnab Scores were seen across the cohort.

CONCLUSION

Biportal spinal endoscopy is a novel method to address pathology in the lumbar spine with direct visualization through an endoscopic approach. Complications are comparable to previously published rates. Clinical outcomes demonstrate effectiveness. Prospective studies are required to assess the efficacy of the technique as compared to traditional techniques. This study demonstrates that the technique can be successful in the lumbar spine.

Comparison of the results of open PLIF versus UBE PLIF in lumbar spinal stenosis: postoperative adjacent segment instability is lesser in UBE

OBJECTIVE

To compare the difference in efficacy between open PLIF and UBE for lumbar spinal stenosis and the effect on postoperative adjacent segment instability.

METHOD

The clinical data of 37 patients with PLIF and 32 patients with UBE for lumbar spinal stenosis were retrospectively analyzed to compare the differences in perioperative conditions and short- and medium-term outcomes.

RESULTS

All 69 patients completed the surgery successfully. The operating time, number of intraoperative fluoroscopies and hospital days were higher in the UBE group than in the open PLIF group. Intraoperative bleeding and postoperative drainage were lower than in the open PLIF group (P < 0.05). The visual analogue scale (VAS) of low back pain was lower in the UBE group than in the open PLIF group at 1 month and 3 months postoperatively (P < 0.05), and there were no statistically significant VAS scores for low back pain in the two groups at 1 day and 6 months postoperatively (P > 0.05). Leg pain VAS scores were lower in the UBE group than in the open PLIF group at 1 month, 3 months and 6 months postoperatively (P < 0.05), and leg pain VAS scores were not statistically significant in both groups at 1 day postoperatively (P > 0.05). The ODI index was lower in the UBE group than in the open PLIF group at 1 day and 1 month postoperatively (P < 0.05) and was not statistically significant in the two groups at 3 months and 6 months postoperatively (P > 0.05). There was no statistically significant difference between the two groups in postoperative interbody height, sagittal diameter of the spinal canal, efficacy of modified MacNab and interbody fusion (P > 0.05). The open PLIF group was more prone to postoperative adjacent vertebral instability than the UBE group, and the difference was statistically significant (P < 0.05).

CONCLUSION

With appropriate indications, the open PLIF group and the UBE group had similar short- and medium-term clinical outcomes for the treatment of lumbar spinal stenosis, but patients in the UBE group had better symptomatic improvement than the open PLIF group at 3 months postoperatively, and the effect on postoperative adjacent vertebral instability was smaller in the endoscopic group than in the open PLIF group.

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.

Complications and Management of Endoscopic Spinal Surgery

In the past, the use of endoscopic spine surgery was limited to intervertebral discectomy; however, it has recently become possible to treat various spinal degenerative diseases, such as spinal stenosis and foraminal stenosis, and the treatment range has also expanded from the lumbar spine to the cervical and thoracic regions. However, as endoscopic spine surgery develops and its indications widen, more diverse and advanced surgical techniques are being introduced, and the complications of endoscopic spine surgery are also increasing accordingly. We searched the PubMed/MEDLINE databases to identify articles on endoscopic spinal surgery, and key words were set as “endoscopic spinal surgery,” “endoscopic cervical foramoinotomy,” “PECD,” “percutaneous transforaminal discectomy,” “percutaneous endoscopic interlaminar discectomy,” “PELD,” “PETD,” “PEID,” “YESS” and “TESSYS.” We analyzed the evidence level and classified the prescribed complications according to the literature. Endoscopic lumbar surgery was divided into full endoscopic interlaminar and transforaminal approaches and a unilateral biportal approach. We performed a comprehensive review of available literature on complications of endoscopic spinal surgery. This study particularly focused on the prevention of complications. Regardless of the surgical methods, the most common complications related to endoscopic spinal surgery include dural tears and perioperative hematoma. transient dysesthesia, nerve root injury and recurrence. However, Endoscopic spinal surgery, including full endoscopic transforaminal and interlaminar and unilateral biportal approaches, is a safe and effective a treatment for lumbar as well as cervical and thoracic spinal diseases such as disc herniation, lumbar spinal stenosis, foraminal stenosis and recurrent disc herniation.

Indications for and Outcomes of Three Unilateral Biportal Endoscopic Approaches for the Decompression of Degenerative Lumbar Spinal Stenosis: A Systematic Review

Objective: In this systematic review, we summarized the indications for and outcomes of three main unilateral biportal endoscopic (UBE) approaches for the decompression of degenerative lumbar spinal stenosis (DLSS). Methods: A comprehensive search of the literature was performed using Ovid Embase, PubMed, Web of Science, and Ovid’s Cochrane Library. The following information was collected: surgical data; patients’ scores on the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Macnab criteria; and surgical complications. Results: In total, 23 articles comprising 7 retrospective comparative studies, 2 prospective comparative studies, 12 retrospectives case series, and 2 randomized controlled trials were selected for quantitative analysis. The interlaminar approach for central and bilateral lateral recess stenoses, contralateral approach for isolated lateral recess stenosis, and paraspinal approach for foraminal stenosis were used in 16, 2, and 4 studies, respectively. In one study, both interlaminar and contralateral approaches were used. L4-5 was the most common level decompressed using the interlaminar and contralateral approaches, whereas L5-S1 was the most common level decompressed using the paraspinal approach. All three approaches provided favorable clinical outcomes at the final follow-up, with considerable improvements in patients’ VAS scores for leg pain (63.6–73.5%) and ODI scores (67.2–71%). The overall complication rate was <6%. Conclusions: The three approaches of UBE surgery are effective and safe for the decompression of various types of DLSS. In the future, long-term prospective studies and randomized control trials are warranted to explore this new technique further and to compare it with conventional surgical techniques.

A single-arm retrospective study of the clinical efficacy of unilateral biportal endoscopic transforaminal lumbar interbody fusion for lumbar spinal stenosis

Objective

The purpose of this study was to investigate the clinical efficacy of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) for lumbar spinal stenosis (LSS).

Methods

Patients who underwent UBE-TLIF due to single-segment LSS between August 2019 and July 2021 were retrospectively included in the study. Clinical outcomes evaluated include operative time, estimated blood loss (including postoperative drainage), time to ambulation, postoperative hospital stay, complications, visual analog scale (VAS) scores of low back pain and leg pain, Japanese Orthopaedic Association (JOA) score, Oswestry disability index (ODI), and modified Macnab criteria. Interbody bony fusion at the index level was assessed using Bridwell grading criteria.

Results

A total of 73 patients (29 males and 44 females) were enrolled in this study. All surgeries were successfully performed without intraoperative conversion to open surgery. Magnetic resonance imaging (MRI) revealed optimal direct neural decompression after UBE-TLIF. The mean operative time was 150.89 ± 15.58 min. The mean estimated blood loss was 126.03 ± 17.85 ml (postoperative drainage was 34.84 ± 8.31 ml). Time to ambulation was 2.0 ± 0.75 days after the procedure. Postoperatively, the mean hospital stay was 5.96 ± 1.38 days. VAS scores of low back pain and leg pain, JOA, and ODI were significantly improved postoperatively compared with those before the operation, and differences were statistically significant (P < 0.05). Excellent and good outcomes were reported by 87.67% of patients according to the modified Macnab criteria at the final follow-up. A total of nine perioperative complications occurred, with an incidence of 12.33%. X-ray or computerized tomography (CT) 6 months after the procedure showed that 37 cases (50.68%) presented with segmental fusion, 30 cases (41.10%) showed incomplete fusion, and 6 cases (8.22%) showed no signs of fusion. However, bony fusion was achieved in all cases at the final follow-up.

Conclusions

UBE-TLIF for LSS has the advantages of less surgical invasiveness and fast postoperative recovery.

Clinical efficacy and imaging outcomes of unilateral biportal endoscopy with unilateral laminotomy for bilateral decompression in the treatment of severe lumbar spinal stenosis

Objective

To investigate the clinical efficacy and imaging outcomes of unilateral biportal endoscopy (UBE) with unilateral laminotomy for bilateral decompression (ULBD) in the treatment of severe lumbar spinal stenosis (SLSS).

Methods

We retrospectively analyzed 50 patients with SLSS treated with UBE-ULBD from October 2018 to March 2021. Visual analog scale (VAS) for back and legs pain, Oswestry disability index (ODI), modified Macnab criteria, complications, hospital stay, preoperative and postoperative dural sac cross-sectional area (DSCA) and Schizas grade, mean angle of facetectomy and osseous lateral recess decompression rate were examined.

Results

The mean follow-up period was 10.7 months. The mean hospital stay was 2.76 ± 1.02 days. At the final follow-up, VAS for back pain and legs pain decreased from 7.22 ± 0.95 to 1.26 ± 0.44 and from 7.88 ± 0.69 to 1.18 ± 0.39, respectively; ODI decreased from 69.88 ± 6.32% to 14.96 ± 2.75%. According to the modified Macnab criteria, the results were excellent in 24 (48%), good in 22 (44%), and fair in 4 (8%). Excellent or good results (a satisfactory outcome) were obtained in 92% of the patients. There were 2 cases of complications of dural sac tear. The postoperative DSCA was significantly enlarged compared with that before surgery, from 44.74 ± 9.85 to 126.86 ± 14.81 mm². According to Schizas grade, the stenosis grade changes from preoperative grade C in 16 cases, grade D in 34 cases, to postoperative grade A in 40 cases, and grade B in 10 cases. The mean angle of facetectomy of the ipsilateral facet joint was 70.87 ± 5.68 ∘ , contralateral was 65.07 ± 4.98 ∘ . The decompression rate was 70.81 ± 4.43% (ipsilateral side) and 71.22 ± 3.68% (contralateral).

Conclusions

UBE-ULBD has a good clinical effect in the treatment of SLSS, and has achieved satisfactory results in spinal canal enlargement, undercutting of facet joints, and decompression effect. It is a safe and effective surgical for SLSS.

Unilateral biportal endoscopic foraminotomy and diskectomy combined with piezosurgery for treating cervical spondylotic radiculopathy with neuropathic radicular pain

Objective

Unilateral biportal endoscopy (UBE) represents a relatively recent development in minimally invasive spine surgery. This study aimed to evaluate the efficacy and safety of UBE foraminotomy and diskectomy combined with piezosurgery for treating cervical spondylotic radiculopathy (CSR) with neuropathic radicular pain.

Methods

We retrospectively analyzed the outcomes in 12 patients with CSR who underwent UBE foraminotomy and diskectomy combined with piezosurgery. The intraoperative blood loss, operative time, visual analog scale (VAS) scores for the neck and arm, neck disability index (NDI) scores, and complications were recorded.

Results

Postoperative VAS scores of the neck and arm and NDI scores were significantly improved. Additionally, a postoperative CT scan revealed adequate enlargement of the cervical canal and nerve root. No specific complications occurred during surgery and the immediate postoperative period.

Conclusions

This primary study indicated that the UBE foraminotomy and diskectomy with piezosurgery is a promising technique for treating cervical spondylotic radiculopathy with neuropathic radicular pain.

Comparison of Unilateral Biportal Endoscopic Discectomy with Other Surgical Technics: A Systemic Review of Indications and Outcomes of Unilateral Biportal Endoscopic Discectomy from the Current Literature

OBJECTIVE

Unilateral biportal endoscopic (UBE) spine surgery for spinal diseases has been increasing in popularity because of its favorable outcomes. The goal of this systemic review is to analyze the status of outcomes and complications in lumbar disc herniation during UBE discectomy.

METHODS

A comprehensive search of the PubMed, Embase, Web of Science, and OVID databases published until June 30, 2021, was performed. The outcomes of interest were indications, operative time, blood loss, hospital stay, complications, visual analog scale score, and Oswestry Disability Index.

RESULTS

Seven studies were included in our research. UBE surgery for lumbar stenosis was excluded. A total of 230 patients with lumbar disc herniation were enrolled in the 7 selected studies. The mean operative time was 74.4 minutes, and the mean length of hospital stay was 4.5 days. Mean incidence of complications reported in the 7 articles was 6.2%. UBE showed shorter hospital stays than did microdiscectomy, no significant differences of Oswestry Disability Index or visual analog scale scores, and good recovery rate among other discectomy techniques (microdiscectomy, full endoscopic transforaminal endoscopic lumbar discectomy, and interlaminar endoscopic lumbar discectomy) at 1 month follow-up.

CONCLUSIONS

Even with the small number of studies and reports analyzed, biases were the main limitation of this analysis; overall, the clinical outcomes and complication rates associated with UBE discectomy were relatively good. It is clear that UBE discectomy is a good treatment choice for lumbar disc herniation, but to prevent unique UBE surgery complications, a clear understanding of the surgical procedures and careful efforts to overcome the learning curve are necessary.

Unilateral biportal endoscopic decompression for symptomatic thoracic ossification of the ligamentum flavum: a case control study

PURPOSE

Thoracic ossification of the ligamentum flavum (OLF) is an uncommon disease that mostly occurs in East Asians. Laminectomy is often considered when patients develop neuro-related symptoms but may associate with treatment-related complications. This study aimed to evaluate the efficacy and safety of unilateral biportal endoscopic (UBE) decompression treatment in patients with symptomatic OLF.

METHODS

From January 2020 to January 2021, patients with spinal cord compression symptoms and imaging-defined single-level thoracic OLF were enrolled in this study and received UBE decompression treatment. Their pre- and postoperative neurological statuses were evaluated by the modified Japanese Orthopaedic Association (mJOA) score, Visual Analog Scale (VAS) for leg pain, and Frankel grade.

RESULTS

Fourteen patients with an average age of 59.4 years were enrolled in the study. The mean operation time was 66.1 ± 15.4 minutes. Patients were followed up for at least one year after receiving the treatment. Our data suggested that their mJOA score (preop 6.2 ± 1.2, 1 year 8.5 ± 0.9; P < 0.001) and VAS score (preop 4.5 ± 2.0, 1 year 0.5 ± 0.9; P < 0.001) were significantly improved compared with that before operation. Cerebrospinal fluid leakage occurred in one patient, head and neck pain occurred in two patients, and hyperalgesia of lower limbs occurred in two patients. All these complications did not cause serious consequences.

CONCLUSION

This primary study indicated that the UBE decompression treatment can achieve satisfactory clinical results in patients with thoracic OLF at single level and provide an alternative treatment option.

Case Report: Bilateral Biportal Endoscopic Open-Door Laminoplasty With the Use of Suture Anchors: A Technical Report and Literature Review

Background

Unilateral biportal endoscopy (UBE) is a newly developed technique for spine surgery. Owing to the convenience of nerve decompression and compatibility with open surgical instruments under endoscopic guidance, this technique has seen widespread global use. In this study, we first used modified UBE with suture anchor fixation for cervical laminoplasty in a 65-year-old female patient with good clinical outcomes.

Methods

We used bilateral biportal endoscopy (BBE) for cervical laminoplasty with suture anchor fixation in a patient with cervical stenosis. Under endoscopic guidance, a bilateral approach was used to make the gutter and lift the lamina door. After the lamina doors were opened, sutures were tied tightly using facia cannula and knot pusher. After confirming the solidarity of the open-door status, the drainage tube was inserted and the incisions were closed. The patient’s pre- and postoperative radiological and clinical results were evaluated.

Results

Postoperative Japanese Orthopaedic Association (JOA) and Neck Disability Index (NDI) scores were improved clinically, and cervical canal was decompressed radiologically.

Conclusions

BBE laminoplasty combined with suture anchor fixation showed a favorable clinical and radiological result and appears to be a safe and effective technique for cervical stenosis.

The Learning Curve of Unilateral Biportal Endoscopic (UBE) Spinal Surgery by CUSUM Analysis

Objective

To assess the learning curve of the unilateral biportal endoscopic (UBE) technique for the treatment of single-level lumbar disc herniation by cumulative summation (CUSUM) method analysis.

Methods

A retrospective analysis was conducted to assess 97 patients' general condition, operation time, complications, and curative effect of single segmental UBE surgery performed by a spinal surgeon in his early stage of this technique. The learning curve of operation time was studied using a CUSUM method, and the cut-off point of the learning curve was obtained.

Results

The operation time was 30 – 241(97.9 ± 34.7) min. The visual analog scale score of lower limb pain decreased from 5.75 ± 0.81 before the operation to 0.39 ± 0.28 at the last follow-up (P &lt; 0.05). The Oswestry disability index score decreased from 66.48 ± 4.43 before the operation to 14.57 ± 3.99 at the last follow-up (P &lt; 0.05). The CUSUM assessment of operation time revealed the learning curve was the highest in 24 cases. In the learning stage (1–24 cases), the operation time was 120.3 ± 43.8 min. In the skilled stage (25–97 cases), the operation time was 90.5 ± 27.8 min.

Conclusions

About 24 cases of single segmental UBE operation are needed to master the UBE technique.

Global and Current Research Trends of Unilateral Biportal Endoscopy/Biportal Endoscopic Spinal Surgery in the Treatment of Lumbar Degenerative Diseases: A Bibliometric and Visualization Study

The study aimed to make a bibliometric analysis of the current research situation in unilateral biportal endoscopy/biportal endoscopic spinal surgery (UBE/BESS). Research data sets were acquired from the Web of Science database. The study chosed “biportal endoscopic spinal surgery” OR “two portal endoscopic spinal surgery” OR “percutaneous biportal endoscopic decompression” OR “unilateral biportal endoscopy” OR “irrigation endoscopic discectomy” as the search terms. The literature search was limited to articles published before March 5, 2021. We only included original articles and reviews. VOS viewer and Citespace software were used to analyze the data and generate visualization knowledge maps. Annual trend of publications, distribution, H‐index status, co‐authorship status, and research hotspots were analyzed. A total of 74 publications met the requirement. The sum number of citations was 31,204, in which 19,336 were no self‐citations. The average citation of all the papers was 21.84 times. The H‐index of all the publications was 85. South Korea's total number of articles was far higher than that of other countries and regions (61, 82.4%), followed by United Arab Emirates, Egypt, and Peoples Republic of China (three, ranking second, accounting for 12.2% of the total). For the most productive authors, Choi ranked first with 21 articles, Kim ranked second with 16 articles, and Heo ranked third with 12 articles. The journal with the greatest number of publications was World Neurosurgery, with a total of 18 (39.1%) papers. Clinics in Orthopedic Surgery ranked second with six (13.0%) papers. In third place, there were fix articles published by Asian Spine Journal and Neurospine, accounting for 21.8% of the total articles. These top three journals accounted for 73.9% of all the papers. Spondylolisthesis and endoscopic decompression were the research hotspots in recent years. The number of publications has showed an upward trend with a stable rise in recent years. South Korea is the country with the highest productivity, not only in quality, but also in quantity. Barun Hosp and Leon Wiltse Mem Hosphave published most articles. Choi is the most productive author. World Neurosurgery is the most productive journal. Spondylolisthesis and endoscopic decompression are the research hotspots in recent years. Indeed, this study provides new insight into the growth and development of UBE/BESS.

Unilateral Biportal Endoscopy for Decompression of Extraforaminal Stenosis at the Lumbosacral Junction: Surgical Techniques and Clinical Outcomes

Objective

The aims of this study were to describe the unilateral biportal endoscopic (UBE) technique for decompression of extraforaminal stenosis at L5–S1 and evaluate 1-year clinical outcomes. Especially, we evaluated compression factors of extraforaminal stenosis at L5–S1 and described the surgical technique for decompression in detail.

Methods

Thirty-five patients who underwent UBE decompression for extraforaminal stenosis at L5–S1 between March 2018 and February 2019 were enrolled. Clinical results were analyzed using the MacNab criteria, the visual analogue scale (VAS) for back and leg pain, and the Oswestry Disability Index (ODI). Compression factors evaluated pseudoarthrosis within the transverse process of L5 and ala of sacrum, disc bulging with or without osteophytes, and the thickened lumbosacral and extraforaminal ligament.

Results

The mean back VAS was 3.7±1.8 before surgery, which dropped to 2.3±0.8 at 1-year postoperative follow-up (p<0.001). There was a significant drop in postoperative mean VAS for leg pain from 7.2±1.1 to 2.3±1.2 at 1 year (p<0.001). The ODI was 61.5 before surgery and 28.6 (p<0.001). Pseudoarthrosis between the transverse process and the ala was noted in all cases (35 of 35, 100%). Pure disc bulging was seen in 12 patients (34.3%), and disc bulging with osteophytes was demonstrated in 23 patients. The thickened lumbosacral and extraforaminal ligament were identified in 19 cases (51.4%). No complications occurred in any of the patients.

Conclusion

In the current study, good surgical outcomes without complications were achieved after UBE decompression for extraforaminal stenosis at L5–S1.

Efficacy and safety of unilateral biportal endoscopy compared with microscopic decompression in the treatment of lumbar spinal stenosis: A protocol for systematic review and meta-analysis

OBJECTIVE

Systematic evaluation of the efficacy and safety of unilateral biportal endoscopic decompression in the treatment of lumbar spinal stenosis.

METHODS

We conducted a systematic literature search and compared the randomized controlled trials (RCTs) and retrospective studies of unilateral biportal endoscopy (UBE) and microscopic decompression (MD) in the treatment of lumbar spinal stenosis from several databases.

RESULTS

Seven studies were included. The results of meta-analysis showed that the operation time of UBE was shorter than that of MD. [SMD = -0.443, 95% CI (-0.717, -0.169), P  = .002]. Compared with MD, the patients' back pain was slighter on the 1st day, 1-2 months and 6 months after UBE. During the long-term follow-up, there was no significant difference in back pain between MD and UBE [SMD = -0.519, 95% CI (-0.934, -0.104), P  = .014]. There was no significant difference in lower limb visual analogue score (VAS) score between UBE decompression and MD [SMD = -0.105, 95% CI (-0.356, 0.146), P  = .412]. The results of meta-analysis showed that the C-reactive protein (CRP) level of UBE was lower than that of MD [weighted mean difference = -1.437, 95% CI (-2.347, -0.527), P  = .002]. There was no significant difference in other clinical effects between the 2 groups.

CONCLUSION

The operation time of UBE was shorter than that of MD, and it was superior to micro decompression in early back VAS score, lower limb VAS score and early postoperative CRP level. There was no statistical difference between UBE and MD in other outcomes.

Decompression Using Minimally Invasive Surgery for Lumbar Spinal Stenosis Associated with Degenerative Spondylolisthesis: A Review

Lumbar spinal stenosis (LSS), which often occurs concurrently with degenerative spondylolisthesis (DS), is a common disease in the elderly population, affecting the quality of life of aged people significantly. Notwithstanding the frequently good effect of conservative therapy on LSS, a minority of the patients ultimately require surgery. Surgery for LSS aims to decompress the narrowed spinal canals with preservation of spinal stability. Traditional open surgery, either pure decompression or decompression with fusion, was considered effective for the treatment of LSS with or without DS. However, the long-term clinical outcomes of traditional open surgery are still unclear. Moreover, the disadvantages of conventional open surgery are extensive, examples including tissue injuries or secondary instability, with limited outcomes and significant reoperation rates. With the development and improvement of surgical tools, various minimally invasive spine surgery (MISS) methods, including indirect decompression techniques of interspinous process devices (IPDs) and direct decompression techniques such as microscopic spine surgery or endoscopic spine surgery (ESS), have been updated with enhancement. IPDs, such as Superion devices, were reported to behave with comparable physical function, disability, and symptoms outcomes to laminectomy decompression. As an emerging technique of MISS, ESS has beneficial hallmarks including minimal tissue injuries, reduced complication rates, and shortened recovery periods, thus gaining popularity in recent years. ESS can be classified in terms of endoscopic hallmarks and approaches. Predictably, with the continuous development and gradual maturity, MISS is expected to replace traditional open surgery widely in the surgical treatment of LSS associated with DS in the future.

Dural Injury in Unilateral Biportal Endoscopic Spinal Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVES

Unilateral biportal endoscopic surgery (UBES) is a popular surgical method used to treat degenerative spinal diseases because of its merits, such as reduced tissue damage and outstanding visual capacity. However, dural injury is the most common complication of UBES with an incidence rate of 1.9% to 5.8%. The purpose of this study was to analyze the pattern of dural injury during UBES and to report the clinical course.

METHODS

We retrospectively reviewed the medical and radiographic records of surgically treated patients who underwent UBES at a single institute between January 2018 and December 2019.

RESULTS

Fifty-three patients, representing 67 segments, underwent UBES. Seven dural injuries occurred, and the incidence rate was 13.2%. Among 16 far lateral approaches, 2 dural injuries of the exiting roots occurred and were treated with fibrin sealant reinforcement. Among 51 median approaches, dural injury occurred at the thecal sac (n = 3) and traversing root (n = 2). A dural injury of the shoulder of the traversing root was treated with a fibrin sealant; however, a defect in the thecal sac required a revision for reconstruction. The other 2 thecal sac injuries were directly repaired via microscopic surgery.

CONCLUSIONS

Dural injury during UBES can occur because of the various anatomical features of the meningo-vertebral ligaments. Direct repair of the central dural defect should be considered under microscopic vision. A linear tear in the lateral dura or root can be controlled with a simple patchy reinforcement under endoscopic vision.

Automatic tip detection of surgical instruments in biportal endoscopic spine surgery

BACKGROUND

Recent advances in robotics and deep learning can be used in endoscopic surgeries and can provide numerous advantages by freeing one of the surgeon's hands. This study aims to automatically detect the tip of the instrument, localize a point, and evaluate the detection accuracy in biportal endoscopic spine surgery (BESS). The tip detection could serve as a preliminary study for the development of vision intelligence in robotic endoscopy.

METHODS

The dataset contains 2310 frames from 9 BESS videos with x and y coordinates of the tip annotated by an expert. We trained two state-of-the-art detectors, RetinaNet and YOLOv2, with bounding boxes centered around the tip annotations with specific margin sizes to determine the optimal margin size for detecting the tip of the instrument and localizing the point. We calculated the recall, precision, and F1-score with a fixed box size for both ground truth tip coordinates and predicted midpoints to compare the performance of the models trained with different margin size bounding boxes.

RESULTS

For RetinaNet, a margin size of 150 pixels was optimal with a recall of 1.000, precision of 0.733, and F1-score of 0.846. For YOLOv2, a margin size of 150 pixels was optimal with a recall of 0.864, precision of 0.808, F1-score of 0.835. Also, the optimal margin size of 150 pixels of RetinaNet was used to cross-validate its overall robustness. The resulting mean recall, precision, and F1-score were 1.000 ± 0.000, 0.767 ± 0.033, and 0.868 ± 0.022, respectively.

CONCLUSIONS

In this study, we evaluated an automatic tip detection method for surgical instruments in endoscopic surgery, compared two state-of-the-art detection algorithms, RetinaNet and YOLOv2, and validated the robustness with cross-validation. This method can be applied in different types of endoscopy tip detection.

Comparison of Minimal Invasive Versus Biportal Endoscopic Transforaminal Lumbar Interbody Fusion for Single-level Lumbar Disease

STUDY DESIGN

Retrospective study.

OBJECTIVE

The authors aimed to compare the clinical outcomes of biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) with those of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) using a microscope.

SUMMARY OF BACKGROUND DATA

Lumbar spinal fusion has been widely performed for various lumbar spinal pathologies. Minimally invasive transforaminal interbody fusion using a tubular retractor under a microscope is a method of achieving fusion while reducing soft tissue injury. Recently, several studies have reported minimally invasive techniques for lumbar discectomy, decompression, and interbody fusion using biportal endoscopic spinal surgery.

MATERIALS AND METHODS

This retrospective study included 87 patients who underwent single-level TLIF for degenerative or isthmic spondylolisthesis between 2015 and 2018. Thirty-two and 55 patients underwent BE-TLIF (group A) and MI-TLIF (group B), respectively. Visual Analogue Scale scores of the back and leg and Oswestry Disability Index were collected perioperatively.Further, data regarding perioperative complications, including length of hospital stay, time to ambulation, and fusion rate, were collected.

RESULTS

The Visual Analogue Scale score at 2 weeks and 2 months postoperatively was significantly lower in group A (P=0.001). All other clinical scores showed improvement with no significant difference between the 2 groups (P>0.05). The difference in the fusion rates between group A (93.7%) and group B (92.7%) were not significant (P=0.43).

CONCLUSIONS

Because BE-TLIF yieldeds lesser early postoperative back pain than did MI-TLIF, it may allow early ambulation and a shorter hospitalization period. BE-TLIF may be a viable alternative to MI-TLIF in patients with degenerative or isthmic spondylolisthesis with superior clinical results in the early postoperative period.

Full-Endoscopic Foraminotomy with a Novel Large Endoscopic Trephine for Severe Degenerative Lumbar Foraminal Stenosis at L5 S1 Level: An Advanced Surgical Technique

To (i) introduce the technical notes of a novel full‐endoscopic foraminotomy with a large endoscopic trephine for the treatment of severe degenerative lumbar foraminal stenosis at L₅S₁ level; (ii) assess the primary clinical outcomes of this technique; (iii) compare the effectiveness of this full‐endoscopic foraminotomy technique and other previous techniques for lumbar foraminal stenosis. From January 2019 to August 2019, a retrospective study of L₅S₁ severe degenerative lumbar foraminal stenosis was performed in our center. All patients who were diagnosed with severe foraminal stenosis at L₅S₁ level and failed conservative treatment for at least 6 weeks were identified. Patients with segmental instability or other coexisting contraindications were excluded. A total of 21 patients were enrolled in the study. All patients were treated by full‐endoscopic foraminotomy using large endoscopic trephine. The visual analogue scale (VAS) and Oswestry disability index (ODI) were evaluated preoperatively and at 1, 3, 6 months, and 1 year after the surgery, and the modified MacNab criteria were used to evaluate clinical outcomes at the last follow‐up. There were 10 males and 11 females with a mean age of 66.38 ± 9.51 years. Five patients had a history of lumbar surgery. The mean operative time was 63.57 ± 25.74 min. The mean follow‐up time was 13.29 ± 1.38 months. The mean postoperative hospital stay time was 1.29 ± 0.56 days. The mean preoperative VAS score significantly decreased from 7.38 ± 1.02 to 2.76 ± 1.09 (t = 19.759, P < 0.01), 2.25 ± 1.02 (t = 21.508, P < 0.01), 1.60 ± 1.05 (t = 31.812, P < 0.01), and 1.45 ± 1.10 (t = 25.156, P < 0.01) at 1 month, 3 months, 6 months, and 1 year after the operation. The mean preoperative ODI score significantly decreased from 64.66% ± 4.91% to 30.69% ± 4.59% (t = 33.724, P < 0.01), 29.44% ± 4.50% (t = 32.117, P < 0.01), 24.22% ± 4.14% (t = 33.951, P < 0.01), and 22.44% ± 4.94% (t = 30.241, P < 0.01) at 1 month, 3 months, 6 months, and 1 year after the operation. At the last follow‐up, 19 patients (90.48%) got excellent or good outcomes. One patient suffered postoperative dysesthesia, and the symptoms were controlled by conversion treatment. One patient took revision surgery due to the incomplete decompression. There were no other major complications. Percutaneous endoscopic decompression is minimally invasive spine surgery. However, the application of endoscopic decompression for L₅S₁ foraminal stenosis is relatively difficult due to the high iliac crest and narrow foramen. Full‐endoscopic foraminotomy with the large endoscopic trephine is an effective and safe technique for the treatment of degenerative lumbar foraminal stenosis.

Clinical Comparison of Unilateral Biportal Endoscopic Laminectomy versus Microendoscopic Laminectomy for Single-Level Laminectomy: A Single-Center, Retrospective Analysis

BACKGROUND

The purpose of this study was to compare clinical results of microendoscopic laminectomy (MEL) with those of unilateral biportal endoscopic laminectomy (UBEL) in patients with single-level lumbar spinal canal stenosis.

METHODS

The subjects consisted of 181 patients who underwent MEL (139 cases) and UBEL (42 cases) who were followed up for at least 6 months. All patients had lumber canal stenosis for 1 level. Outcomes of the patients were assessed with the duration of surgery, the bone resection area in 3-dimensional computed tomography, the facet preservation rates in computed tomography axial imagery, Visual Analog Scale (VAS) for low back pain, the Oswestry Disability Index, and the EuroQol 5-Dimensions questionnaire.

RESULTS

The bone resection area in 3-dimensional computed tomography was 1.5 for MEL versus 1.0 cm² for UBEL (P < 0.05). The facet preservation rates on the advancing side and the opposite side were 78% versus 86% (advancing side: MEL vs. UBEL) and 85% versus 94% (opposite side) (P < 0.05). The VAS (low back pain) score, VAS (leg pain), Oswestry Disability Index, and EuroQol 5-Dimension questionnaire significantly dropped in both groups at the final period (P < 0.05), however, exhibiting no difference between the 2 groups at each period. MEL resulted in greater numbers of complications, including 5 cases of hematoma paralysis, 8 cases of dura injury, 2 cases of reoperation, as opposed to zero cases of hematoma paralysis and only 2 cases of dura injury resulting from UBEL.

CONCLUSIONS

The UBEL method is a more useful technique than the MEL method as it requires a smaller bone resection area and produces fewer complications.

How I do it? Extraforaminal lumbar interbody fusion assisted with biportal endoscopic technique

BACKGROUND

The biportal endoscope-assisted unilateral foraminal approach is an option for various foraminal pathologies. Lumbar interbody fusion is the standard treatment for foraminal stenosis because both direct and indirect neural decompressions can be obtained.

METHOD

We used the biportal endoscopic technique for extraforaminal lumbar interbody fusion (BE-EFLIF) and have described the steps, with discussion regarding the indications, advantages, possible complications, and ways to overcome complications.

CONCLUSION

BE-EFLIF achieves direct neural decompression of lateral spinal canal under endoscopic visualization. It achieves indirect neural decompression using a large footprint lordotic interbody cage, while preserving the lumbar posterior arch as much as possible.

Current and Future of Endoscopic Spine Surgery: What are the Common Procedures we Have Now and What Lies Ahead?

The aging population around the world leads to increasing incidence of degenerative spinal conditions. There is a need for a minimally invasive technique in treatment for spinal conditions to meet the medical complexity and comorbidities that comes with aging. Principles of endoscopy are similar to minimally invasive surgery, which is to decrease pressure on soft tissue crushing from prolonged retraction, avoid soft tissue stripping and dissection, and bone and ligamentous preservation for optimal decompression without excessive destruction. Endoscopic spine surgery techniques started slowly in development in the 1970s to 2000s, with a rapid phase of development since the turn of the 21st century with endoscopic solutions developing in cervical, thoracic, and lumbar conditions with increasing complexity in nature of operation. Technological enhancement with progressively supportive literature is pushing boundaries of endoscopy from the early days of soft tissue procedure to current fusion procedures, endoscopic spine surgery techniques is covering more areas of spine than ever previously possible with good clinical results. We present a review on the current techniques available and postulated near future development for endoscopic spine surgery.

A Narrative Review of Development of Full-Endoscopic Lumbar Spine Surgery

In the first phase of development of lumbar endoscopic spine surgery, the focus was on removal of soft disc material through the working corridor of Kambin’s triangle using transforaminal endoscopic lumbar discectomy. With the introduction of the interlaminar approach and increased interest from both industry and surgeons, there has been an exponential development of endoscopic surgical equipment and a corresponding expansion of endoscopic techniques. Endoscopic treatment strategies are applied to conditions ranging from contained prolapsed intervertebral discs to noncontained migrated herniated discs, hard calcified discs, spinal stenosis in the central or lateral recess and the foraminal and extraforaminal region, and other combinations of degenerative conditions requiring decompression or fusion surgery. The further expansion of endoscopic surgical management involving complicated spinal cases and the final quartet of trauma, infections, tumors, and possibly deformities could be the future stage of endoscopic spine surgery development. This article covers the full range of current treatment strategies and presents possible future developments of endoscopic spine surgery for the management of lumbar spinal conditions.

Endoscopic Unilateral Laminotomy with Bilateral Discectomy Using Biportal Endoscopic Approach: Technical Report and Preliminary Clinical Results

BACKGROUND

Bilateral or huge disc herniations cause bilateral radiculopathy and severe lower back pain. In such cases, a bilateral discectomy may be required to resolve the radicular pain in both legs. We attempted a surgical technique involving bilateral lumbar discectomy via a unilateral approach using a percutaneous biportal endoscopic technique. The purpose of the present study was to describe our surgical technique and investigate the clinical outcomes in symptomatic bilateral lumbar disc herniation.

METHODS

Eleven patients with bilateral disc herniation of the L4-L5 or L5-S1 segments were surgically treated using the percutaneous biportal endoscopic approach. Biportal endoscopic unilateral laminotomy with bilateral discectomy was performed in all patients. Postoperative magnetic resonance imaging was performed 1 day after surgery, and the clinical parameters were investigated preoperatively and postoperatively.

RESULTS

All enrolled patients were successfully treated by biportal endoscopic bilateral discectomy via a unilateral approach. Surgery was performed at the L4-L5 level in 1 patient and the L5-S1 level in 10 patients. The mean operative time was 67.5 ± 13.1 minutes. A visual analog scale of leg pain and the Oswestry disability index showed significant improvement after surgery (P < 0.05).

CONCLUSION

Endoscopic unilateral laminotomy with bilateral discectomy using the percutaneous biportal endoscopic approach could be an effective and alternative treatment of symptomatic bilateral herniated disc disease affecting L4-L5 or L5-S1 segments.

Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis

Biportal endoscopic spinal surgery (BESS) is a minimally invasive spinal surgery, which is basically similar to microscopic spinal surgery in terms of the use of floating technique and technically similar to conventional percutaneous endoscopic spinal surgery in terms of the use of endoscopic or arthroscopic instruments. Using two independent portals (viewing and working) and maintaining a certain distance from the bony and neural structures allow closer access to the target lesion through a panoramic view by free handling of the scope and instruments rather than through a fixed view by docking into the Kambin’s triangle. Minimally invasive surgery allows for reduced dissection and inevitable muscle injury, preserving stability and reducing risks of restabilization. The purpose of fusion surgery is the same as that of the three surgical techniques stated above. Its wider range of view helps to overcome limitations of conventional endoscopic spinal surgery and to supplement the weak points of microscopic spinal surgery, such as limited working space in a tubular retractor and difficulty in accessing the contralateral area. This technique provides an alternative to unilateral or bilateral decompression of lumbar central spinal stenosis, foraminal stenosis, low-grade spondylolisthesis, and adjacent segment degeneration. Early clinical outcomes are promising despite potential for complications, such as dural tearing and postoperative epidural hematoma, similar to other procedures. Merits of BESS include decreased postoperative infection rate due to continuous irrigation throughout the procedure and decreased need for fusion surgery for one- or two-level lumbar stenosis by wide sublaminar and foraminal decompression with minimal sacrifice of stabilizing structures.

Biportal Endoscopic Spinal Surgery for Bilateral Lumbar Foraminal Decompression by Switching Surgeon's Position and Primary 2 Portals: A Report of 2 Cases With Technical Note

Total facetectomy with/without fusion and facet-preserving microforaminotomy have been performed as conventional surgical treatments for lumbar foraminal stenosis (LFS). Recently, endoscopic spinal surgery has been introduced as a minimally invasive therapeutic modality of LFS by several authors. We report two cases of bilateral LFS at lumbosacral junction level successfully treated with a novel biportal endoscopic spine surgery (BES) technique using primary 2 portals. Two patients presented with chronic onset of back pain and neurogenic claudication symptom. They were diagnosed with bilateral LFS at L5-S1 level from magnetic resonance imaging and computed tomography preoperatively. BES for bilateral foraminal decompression was performed via contralateral approach bilaterally without additional skin incision or surgical trajectory by switching surgeon's position and primary 2 portals. After the surgery, preoperative patients' back and leg pain resolved and unilateral leg weakness of the 2 patients gradually improved in a few months. Postoperative radiologic images revealed significantly enlarged bilateral foramens at L5-S1 level.

Endoscopic Ventral Decompression for Spinal Stenosis with Degenerative Spondylolisthesis by Partially Removing Posterosuperior Margin Underneath the Slipping Vertebral Body: Technical Note and Outcome Evaluation

BACKGROUND

Decompression alone is a treatment option in patients with lumbar spinal stenosis (LSS) and degenerative lumbar spondylolisthesis (DLS). This study aims to describe the procedure of percutaneous transforaminal endoscopic ventral decompression technique and to demonstrate the clinical outcomes.

METHODS

Two years of retrospective data were collected from 26 patients with predominant unilateral leg pain caused by LSS and low-grade DLS (Meyerding grades I and Ⅱ). All patients underwent endoscopic ventral decompression by removing the posterosuperior margin underneath the slipping vertebral body, combined with dorsal decompression without excessive resection of facet joints. The surgical outcomes were assessed using the visual analog scale (VAS), Oswestry Disability Index (ODI), modified MacNab criteria, and walking distance improvement evaluation.

RESULTS

The mean age of the 18 women and 8 men was 69.2 years. The mean preoperative ODI and VAS of the leg and the back scores were 64.7 ± 8.1, 7.0 ± 1.4, and 3.0 ± 1.2, respectively. All mean scores improved postoperatively to 31.4 ± 5.6, 2.4 ± 1.1, and 1.7 ± 1.1 at the final follow-up. In 88.5% of cases, patients' estimated walking distance improved. The outcomes of the modified MacNab criteria showed that 81.3% of patients obtained good-to-excellent rate. There were no statistically significant differences between the percent slip of spondylolisthesis before surgery and at the end of follow-up.

CONCLUSIONS

Based on the initial short-term follow-up results, transforaminal endoscopic ventral decompression by partially removing the posterosuperior margin underneath the slipping vertebral body, combined with dorsal decompression, might be an efficient alternative treatment for leg dominant symptoms in patients with LSS and low-grade DLS.