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

Evolution, Current Trends, and Latest Advances of Endoscopic Spine Surgery

Background: The aging of the population in developing and developed countries has led to a significant increase in the health burden of spinal diseases. These elderly patients often have a number of medical comorbidities due to aging. The need for minimally invasive techniques to address spinal disorders in this elderly population group cannot be stressed enough. Minimally invasive spine surgery (MISS) has several proven benefits, such as minimal muscle trauma, minimal bony resection, lesser postoperative pain, decreased infection rate, and shorter hospital stay. Methods: A comprehensive search of the literature was performed using PubMed. Results: Over the past 40 years, constant efforts have been made to develop newer techniques of spine surgery. Endoscopic spine surgery is one such subset of MISS, which has all the benefits of modern MISS. Endoscopic spine surgery was initially limited only to the treatment of lumbar disc herniation. With improvements in optics, endoscopes, endoscopic drills and shavers, and irrigation pumps, there has been a paradigm shift. Endoscopic spine surgery can now be performed with high magnification, thus allowing its application not only to lumbar spinal stenosis but also to spinal fusion surgeries and cervical and thoracic pathology as well. There has been increasing evidence in support of these newer techniques of spine surgery. Conclusions: For this report, we studied the currently available literature and outlined the historical evolution of endoscopic spine surgery, the various endoscopic systems and techniques available, and the current applications of endoscopic techniques as an alternative to traditional spinal surgery.

Enhanced technique of dural closure using autologous fat graft and Gelfoam for effective management of dural tear following interlaminar endoscopic lumbar spine surgery

BACKGROUND

Incidental dural tears are common complications in lumbar spine surgery, particularly in endoscopic procedures where primary closure via suturing is challenging. The absence of a standardized approach for dural closure in endoscopic spine surgery necessitates exploring alternative techniques.

OBJECTIVE

This study introduces a surgical technique for dural closure utilizing fat graft and Gelfoam, offering an effective alternative to standard approaches in endoscopic spine surgery.

METHODS

Surgical data from patients who underwent interlaminar endoscopic discectomy or stenosis decompression at Lerdsin Hospital from October 2014 to October 2021 were analyzed.

RESULTS

Among 393 cases, dural tears occurred in 2% (8 patients). Our technique achieved successful closure in all these cases, with no incidents of cerebrospinal fluid leakage or wound complications. The majority of patients showed favorable clinical outcomes, except for one case involving concomitant nerve root injury.

CONCLUSION

This study demonstrates that using fat graft and Gelfoam for dural closure is a simple, reliable, and safe technique, particularly effective for challenging-to-repair areas in interlaminar endoscopic lumbar spine surgery.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Evolution of Cervical Endoscopic Spine Surgery: Current Progress and Future Directions-A Narrative Review

Cervical endoscopic spine surgery is rapidly evolving and gaining popularity for the treatment of cervical radiculopathy and myelopathy. This approach significantly reduces muscular damage and blood loss by minimizing soft tissue stripping, leading to less postoperative pain and a faster postoperative recovery. As scientific evidence accumulates, the efficacy and safety of cervical endoscopic spine surgery are continually affirmed. Both anterior and posterior endoscopic approaches have surfaced as viable alternative treatments for various cervical spine pathologies. Newer techniques, such as endoscopic-assisted fusion, the anterior transcorporeal approach, and unilateral laminotomy for bilateral decompression, have been developed to enhance clinical outcomes and broaden surgical indications. Despite its advantages, this approach faces challenges, including a steep learning curve, increased radiation exposure for both surgeons and patients, and a relative limitation in addressing multi-level pathologies. However, the future of cervical endoscopic spine surgery is promising, with potential enhancements in clinical outcomes and safety on the horizon. This progress is fueled by integrating advanced imaging and navigation technologies, applying regional anesthesia for improved and facilitated postoperative recovery, and incorporating cutting-edge technologies, such as augmented reality. With these advancements, cervical endoscopic spine surgery is poised to broaden its scope in treating cervical spine pathologies while maintaining the benefits of minimized tissue damage and rapid recovery.

Comparison of the Outcomes of Microendoscopic Discectomy Versus Full-Endoscopic Discectomy for the Treatment of L4/5 Lumbar Disc Herniation

STUDY DESIGN

Retrospective Comparative Study.

OBJECTIVES

To compare the outcomes of microendoscopic discectomy (MED) versus full-endoscopic discectomy (FED) for treating L4/5 lumbar disc herniation (LDH).

METHODS

A retrospective study was performed on patients with L4/5 LDH treated using MED (n = 249) or FED (n = 124). A 16-mm tubular retractor and endoscope was used for MED, while a 4.1-mm working channel endoscope was used for FED. Patient background and operative data were collected. The Oswestry Disability Index (ODI) and European Quality of Life-5 Dimensions (EQ-5D) scores were recorded preoperatively and at 1 and 2 years postsurgery.

RESULTS

The background data of the two groups were similar. The mean operation times for MED and FED were 59.3 and 47.7 min (respectively), and the mean volumes of removed nucleus pulposus were .65 and 1.03 g, respectively. These differences were significant (P < .001). Six dural tears and one postoperative hematoma were observed in the MED group; none were observed in the FED group. During the follow-up period, 16 MED and 7 FED patients required re-operation due to recurrence (P = 1.00). Although the ODI and EQ-5D scores significantly improved at 1 and 2 years postsurgery in both groups, the differences were not statistically significant.

CONCLUSIONS

Operative outcomes were almost identical in both groups. We did not observe any operative or postoperative complications in FED. We, therefore, recommend FED as the first option for the treatment of L4/5 LDH since it has a better safety profile and is minimally invasive.

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

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

Remove the infected interbody cage using endoscopy in lumbar spine revision surgery: A case series and technique report

BACKGROUND

Current revision surgery to remove the infected interbody cage following transforaminal lumbar interbody fusion (TLIF) surgery is challenging and traumatic. The purpose of this study is to introduce a novel surgical technique to remove the infected interbody cage for chronic infection.

METHODS

Three patients with chronic infection following TLIF surgery underwent revision surgery. Instrumentations were removed and a spinal endoscope was obliquely inserted to the disc space through the initial annular breach. Under endoscope, the cage was found, released, turned around, and dragged to the posterior edge of the disc space. The cage was then removed without distracting the dural sac and nerve roots. For two cases, appropriately sized structural iliac bone grafts were used for interbody fusion without extra instrumentations.

RESULTS

Using endoscope, the interbody cage was easy to identify and expose without disrupting the dural sac and nerve roots. With various endoscopic tools, the cage was easily released and removed. In this case series, the infected interbody cage was removed within thirty minutes without dural sac rupture and nerve root injury. The infection was controlled after the surgery, and the patients obtained good clinical outcomes. At 6-month follow-up, bony fusion was achieved in two patients who underwent interbody fusion.

CONCLUSIONS

This endoscopy assisted technique simplified the revision surgery for chronic infection followed TLIF surgery, with the advantages of no disruption of the neural tissues, bright surgical field and complete disc debridement.

Large-Scale Comparative Study Between Microendoscopic Laminectomy and Full-Endoscopic Laminectomy for the Treatment of Single-Level Lumbar Spinal Canal Stenosis

BACKGROUND

We previously compared the operative outcomes of microendoscopic laminectomy (MEL) and full-endoscopic laminectomy (FEL) for single-level lumbar spinal canal stenosis (LSCS). In this initial report, the operative outcomes of FEL were not inferior to those of MEL.

OBJECTIVE

The purpose of this study is to compare the outcomes of MEL and FEL for single-level LSCS on a large scale using widely used multiple evaluation methods.

METHODS

MEL was performed using a 16 mm tubular retractor and an endoscope, while FEL was performed using a 6.4 mm working channel endoscope. A retrospective study was performed on patients with LSCS treated with MEL (n = 355) or FEL (n = 154). Patient background and operative data were also collected. The Oswestry Disability Index (ODI), European Quality of Life-5 Dimensions (EQ-5D), and 36-item Short Form Survey (SF-36) scores were recorded preoperatively and 1-year postoperatively.

RESULTS

Background data of the two groups and the mean operation time (MEL, 72.1 m; FEL, 74.2 m) were not significant (p>0.2). The mean volumes of intraoperative bleeding (MEL, 25.2 ml; FEL, 10.3 ml) were significantly different (p<0.001). The mean postoperative hospital stays (MEL, 3.9 days; FEL, 2.1 days) were significantly different (p<0.001). Fifteen dural tears (MEL, 11; FEL, 4) and 1 surgical site infection (MEL, 1; FEL, 0) were observed but not significant (p>0.5). Reoperation was required for postoperative hematoma in five patients (MEL, 3; FEL, 2). Although the ODI, EQ-5D, and SF-36 scores improved significantly at one year postoperatively in the MEL and FEL groups (p<0.001), there were no significant differences between the two groups (p>0.1).

CONCLUSION

The operative outcomes and minimal invasiveness were no statistical difference between the MEL and FEL groups. Further development of the operative techniques and the instruments of FEL are required to shorten the operation time.

A Modified Laminotomy for Interlaminar Endoscopic Lumbar Discectomy: Technical Report and Preliminary Results

OBJECTIVE

To introduce a technique of laminotomy using a common trephine to enlarge the interlaminar space at L4/5 segment for interlaminar endoscopic lumbar discectomy (IELD) and report the anatomical basis of this procedure, technical details, as well as primary clinical outcomes of a consecutive patient cohort with L4/5 lumbar disc herniation (LDH).

METHODS

On anteroposterior fluoroscopy, the intersection of the medial edge of the inferior articular process and the inferior endplate of L4 vertebra was taken as the target. Using a common trephine, laminotomy was performed to remove a big portion of the posterior wall of the canal under the guidance of endoscopy. From June 2018 to December 2021, the consecutive patients who underwent L4/5 IELD were prospectively studied. Clinical outcomes were assessed at the day before surgery, 1 day, 1 month, 3 months, 12 months after surgery, and the last follow-up. Numerical Rating Scale, Roland-Morris Disability Questionnaire (RMDQ), and MacNab criteria were used to evaluate back and leg pain, the quality of life, and clinical efficacy, respectively.

RESULTS

There were 64 men and 44 women, with an age of 50.3 ± 14.9 years. The operating time was 74.54 ± 17.42 minutes. The mean follow-up time was 32.7 ± 18.6 months (range, 12-64 months). The complications of IELD included numbness, neck pain, and recurrence. Both leg pain (6.2 ± 1.9 vs. 1.8 ± 0.8, p < 0.001) and back pain (3.1 ± 2.3 vs. 1.7 ± 0.9, p < 0.001) quickly improved after this procedure and maintained (1.1 ± 1.5, 1.1 ± 1.3) at final follow-up. Physical disability due to back pain, as assessed using RMDQ, was improved remarkably after surgery (15.0 ± 5.8 vs. 2.9 ± 4.1, p < 0.001). In addition, MacNab outcome grade was evaluated as good-to-excellent in 96 cases (88.9%).

CONCLUSION

A convenient technique of laminotomy using a common trephine was proposed for the L4/5 IELD. It can efficiently enlarge the interlaminar entry to perform endoscopic discectomy. This procedure is particularly suitable for treating LDH with concomitant lumbar spinal stenosis and migrated herniated disc.

Future of Endoscopic Spine Surgery: Insights from Cutting-Edge Technology in the Industrial Field

In the evolving landscape of spinal surgery, technological advancements play a pivotal role in enhancing surgical outcomes and patient experiences. This paper delves into the cutting-edge technologies underpinning endoscopic spine surgery (ESS), specifically highlighting the innovations in scope cameras, RF equipment, and drills. The modern scope camera, with its capability for high-resolution imaging, offers surgeons unparalleled visualization, enabling precise interventions. Radiofrequency (RF) equipment has emerged as a crucial tool, providing efficient energy delivery for tissue modulation without significant collateral damage. Drills, with their enhanced torque and adaptability, allow for meticulous bone work, ensuring structural integrity. As minimally invasive spine surgery (MISS) becomes the standard, the integration and optimization of these technologies are paramount. This review captures the current state of these tools and anticipates their continued evolution, setting the stage for the next frontier in spinal surgery.

Intracranial Pressure Evaluation in Swine During Full-Endoscopic Lumbar Spine Surgery

BACKGROUND

Neurological complications during full-endoscopic spine surgery (FESS) might be attributed to intracranial pressure (ICP) increase due to continuous saline infusion (CSI). Understanding CSI and ICP correlation might modify irrigation pump usage. This study aimed to evaluate invasive ICP during interlaminar FESS; correlate ICP with irrigation pump parameters (IPPs); evaluate ICP during saline outflow occlusion, commonly used to control bleeding and improve the surgeon's view; and, after durotomy, simulate accidental dural tear.

METHODS

Five swine were monitored, submitted to total intravenous anesthesia, and positioned ventrally. A parenchymal catheter was installed through a skull burr for ICP monitoring. Lumbar interlaminar FESS was performed until exposure of neural structures. CSI was used within progressively higher IPPs (A [60 mm Hg, 350 mL/minute] to D [150 mm Hg, 700 mL/minute]), and ICP was documented. During each IPP, different situations were grouped: intact dura with open channels (A1-D1) or occlusion test (A2-D2); dural tear with open channels (Ax1-Dx1) or occlusion test (Ax2-Dx2). ICP <20 mm Hg was defined as safe.

RESULTS

Basal average ICP was 8.1 mm Hg. Adjustment in total intravenous anesthesia or suspension of tests was necessary due to critical ICP or animal discomfort. It was safe to operate with all IPPs with opened drainage channels (A1-D1) even with dural tear (Ax1-Dx1). Several occlusion tests (A2-D2, Ax2-Dx2) caused ICP increase (e.g., 86.1 mm Hg) influenced by anesthetic state and hemodynamics.

CONCLUSIONS

During FESS, CSI might critically raise ICP. Keeping drainage channels open, with ideal anesthetic state, ICP remains safe even with high IPPs, despite dural tear. Drainage occlusions can quickly raise ICP, being even more severe with higher IPPs. Total intravenous anesthesia may protect from ICP increase and may allow longer drainage occlusion or higher IPPs.

Transforaminal Endoscopic Discectomy for Thoracolumbar Disc Herniation: A Retrospective Study and Technical Note

BACKGROUND

Thoracolumbar disc herniation (TLDH) is a rare disorder with unique characteristics that can result in undesirable surgical outcomes after traditional discectomy. In view of the widespread use of transforaminal endoscopic discectomy for lower lumbar disc herniation, we investigated treatment of TLDH by this procedure. The purpose of this study was to evaluate the clinical efficacy of transforaminal endoscopic discectomy for treating TLDH and share our technical experience.

METHODS

We retrospectively evaluated the clinical data of 19 patients who had undergone transforaminal endoscopic discectomy for TLDH in our institution between April 2018 and July 2021. Operation time, follow-up time, blood loss, postoperative hospital stay, visual analog scale scores for low-back and leg pain, and Japanese Orthopedic Association (JOA) scores were evaluated.

RESULTS

The differences between preoperative and postoperative JOA and visual analog scale scores were significant (P < 0.05). According to the JOA scores, 14 of the 19 patients had excellent improvement, 3 had good improvement, and 2 had fair improvement; thus, the rate of satisfactory improvement was 89.5%.

CONCLUSIONS

Operation time, blood loss, postoperative hospital stay, and surgical outcomes were favorable. Transforaminal endoscopic discectomy is an ideal surgical procedure for treating TLDH.

Analysis of the therapeutic effect and postoperative complications associated with 3-dimensional computed tomography navigation-assisted intervertebral foraminoscopic surgery in lumbar disc herniation in the elderly: a retrospective cohort study

Background

With the increasing aging of the population, the incidence of lumbar disc herniation (LDH) is gradually increasing. The 3-dimensional (3D) computed tomography (CT) navigation-assisted intervertebral foraminoscopic surgery for LDH is minimally invasive, and due to its localization and guidance features, it can precisely reach the target location. This study sought to investigate the treatment effect and the incidence of postoperative complications of 3D CT navigation-assisted intervertebral foraminoscopic surgery in elderly patients with LDH to provide a reference basis for improving patient prognosis.

Methods

We retrospectively included 213 elderly patients with LDH admitted to our hospital from October 2017 to October 2021 in this study and followed them up for 1 year. Among them, 103 patients (Group A) underwent conventional C-arm fluoroscopy-assisted system alone intervertebral foraminoscopic surgery, and 110 patients (Group B) underwent 3D CT navigation-assisted intervertebral foraminoscopic surgery. The general characteristics of the participants were compiled using a general information questionnaire designed by the investigator. The t-test and chi-square test were used to analyze the relationship between the treatment outcomes and surgical modalities. Binary logistics regression was used to analyze the independent risk factors affecting patient outcomes.

Results

The patients who underwent 3D CT navigation-assisted intervertebral foraminoscopic surgery had significantly better outcomes than those who underwent conventional C-arm fluoroscopy-assisted system alone intervertebral foraminoscopic surgery. The binary logistic regression analysis results showed that in addition to the surgical method [odds ratio (OR) =0.258, P=0.042], the history of lumbar trauma (OR =11.001, P=0.005), usual work intensity (OR =4.589, P=0.002), disease duration (OR =3.587, P=0.017), the presence of diabetes (OR =3.315, P=0.026), the presence of a ruptured annulus fibrosus (OR =3.485, P=0.012), the degree of disc degeneration (OR =3.899, P=0.009), and the number of punctures (OR =0.412, P=0.034) were independent risk factors affecting patient outcomes.

Conclusions

3D CT navigation-assisted intervertebral foraminoscopic surgery for LDH effectively reduced the number of punctures, decreased intraoperative bleeding and postoperative drainage volumes, shortened the length of hospitalization, bed rest time and operative time, reduced stress reactions, decreased the degree of low-back pain, and the risk of complications, had better overall efficacy, and significantly improved patient prognosis.

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

Background Context

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

Methods

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

Results

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

Conclusions

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

Efficacy of the erector spinae plane block with sedation for unilateral biportal endoscopic spine surgery and comparison with other anesthetic methods

BACKGROUND

Erector spinae plane block (ESPB) is a new regional anesthesia. Unilateral biportal endoscopic (UBE) spine surgery, a minimal invasive technique, has been performed under not only general anesthesia (GA) but regional anesthesia including spinal anesthesia (SA). The aims of this study were to evaluate the efficacy of ESPB with sedation for UBE lumbar decompression and compare it with GA and SA.

METHOD

A retrospective age matched case-control study design was performed. Three groups (20 patients in each group) of patients who underwent UBE lumbar decompressions under each anesthetic method (GA, SA, or ESPB) were formed. The total anesthesia time excluding operation time, postoperative analgesia effects, hospital days, and complications related to anesthetic methods were evaluated.

RESULTS

In the ESPB group, all the operations were performed without change of anesthetic methods and without anesthetic complications. But there were no anesthetic effects in the epidural space, which resulted in additional intravenous fentanyl usage. The mean of time from initiation of anesthesia to completion of surgical preparation was 23.3 ± 4.7 min in the ESPB group, which was shorter than 32.3 ± 10.8 min in the GA (p value = 0.001) or 33.3 ± 6.7 min in the SA group (p < 0.001). The proportion of patients requiring first rescue analgesia within 30 min was 30% in the ESPB group, which was lower than 85% in the GA (p < 0.001), but no significant different with 10% in the SA (p = 0.11). The mean of total hospital days in the ESPB was 3.0 ± 0.8, shorter than 3.7 ± 1.8 in the GA (p = 0.02) or 3.8 ± 1.1 in the SA group (p = 0.01). There was no case of postoperative nausea and vomiting in the ESBB even without prophylactic antiemesis.

CONCLUSION

ESPB with sedation is a viable anesthetic option for UBE lumbar decompression.

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.

2nd and 3rd generation full endoscopic lumbar spine surgery: clinical safety and learning curve

AIM

2nd and 3rd generation endoscopic spine surgery techniques offer visualisation of familiar inter-laminar anatomy to spinal surgeons. We have prospectively evaluated the clinical outcome, complications and learning curve associated with these techniques in patients with lumbar spine radiculopathy.

METHODS

This is a prospective study of 50 consecutive patients with radicular pain from disc herniation and/or lateral recess stenosis. In 6 patients, endoscopy couldn't be done. Operating times, PROM's (VAS, ODI and EQ-5D scores) and complication rates of 44 patients were evaluated after mean FU of 52 months (range 39-65). MRI was used to divide these into protrusions (n = 19), extrusions (n = 17) and lateral recess stenosis (n = 8). Evidence about the learning curve was gathered by curvilinear regression analyses.

RESULTS

Using a composite clinical success criterion, 95% patients had a successful outcome, with no major complications. ODI, VAS and EQ-5D scores had a statistically significant improvement and achieved MCID. Revision discectomy rate was only 4.5% (n = 2). MRI based grouping, case sequence and degree of difficulty influenced the duration of surgery and a learning curve was found for protrusions and lateral recess decompressions, but not for extrusions. A learning curve effect was also observed with respect to the ODI.

CONCLUSIONS

Although anatomy visualised in 2nd and 3rd generation endoscopy is familiar to spinal surgeons, our learning curve experience suggests a careful and MRI pathology based take up of this technique in clinical practice, despite its clinical safety in our series.

LEVEL OF EVIDENCE

Level 3, prospective cohort study.

Incidence and management of dural tears in full-endoscopic unilateral laminotomies for bilateral lumbar decompression

PURPOSE

To report incidence of dural lacerations in lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) and to describe patient outcomes following a novel full-endoscopic bimanual durotomy repair.

METHODS

Retrospective review of prospectively collected database including 5.5 years of single surgeon experience with LE-ULBD. Patients with no durotomy were compared with patients who experienced intraoperative durotomy, including demographics, ASA score, prior surgery, number of levels treated, procedure time, hospital length of stay (LOS), visual analogue scale, perioperative complications, revision surgeries, use of analgesics, and Oswestry Disability Index (ODI).

RESULTS

In total, 13/174 patients (7.5%) undergoing LE-ULBD experienced intraoperative durotomy. No significant differences in demographic, clinical or operative variables were identified between the 2 groups. Sustaining a durotomy increased LOS (p = 0.0019); no differences in perioperative complications or rate of revision surgery were identified. There was no difference in minimally clinically important difference for ODI between groups (65.6% for no durotomy versus 55.6% for durotomy, p = 0.54).

CONCLUSION

In this cohort, sustaining a durotomy increased LOS but, with accompanying intraoperative repair, did not significantly affect rate of complications, revision surgery or functional outcomes. Our method of bimanual endoscopic dural repair provides an effective approach for repair of dural lacerations in interlaminar ULBD cases.

Full-endoscopic bilateral over-the-top decompression in lumbar central stenosis: surgical technique and outcomes

Decompression of spinal stenosis represents one of the most commonly performed procedures in spine surgery. With constantly increasing patient age and changing demographics, reducing the invasiveness of surgical procedures has become increasingly important. Over the past decades, microsurgical decompression has been established as a gold standard technique for the surgical treatment of spinal stenosis. In comparison with open techniques or surgeries that were performed with loop lenses, which required larger skin incisions, and which consecutively raised the access-related collateral damage, the microscope served to significantly reduce the invasiveness of the decompression interventions. Advantages included smaller skin incisions, reduced collateral tissue damage, less blood loss, lower infection rates and wound healing problems, shorter hospital stay, and multiple others, as widely known across various MIS techniques. For the same reasons as outlined above, the introduction of full-endoscopic surgical techniques aims to further reduce the invasiveness of surgical interventions. The present manuscript provides a delineation of the surgical technique of LE-ULBD (Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression), gives an overview on the current state of literature, and aims to put this surgery into context with other currently available decompression techniques.

Efficacy of Transforaminal Endoscopic Lumbar Discectomy in Elderly Patients Over 65 Years of Age Compared to Young Adults

OBJECTIVE

Spine surgery rates are increasing in the elderly population due to social aging, and it is known that prognoses related to surgery are worse for the elderly compared to younger individuals. However, minimally invasive surgery, such as full endoscopic surgery, is considered safe with low complication rates due to minimal damage to surrounding tissues. In this study, we compared outcomes of transforaminal endoscopic lumbar discectomy (TELD) in elderly and younger patients with disc herniation in the lumbosacral region.

METHODS

We retrospectively analyzed the data of 249 patients who underwent TELD at a single center between January 2016 to December 2019, with a minimum follow-up of 3 years. Patients were allocated to 2 groups: a young group aged ≤ 65 years (n = 202) or an elderly group aged > 65 years (n = 47). We evaluated baseline characteristics, clinical outcomes, surgery-related outcomes, radiological outcomes, perioperative complications, and adverse events during the 3-year follow-up period.

RESULTS

Baseline characteristics, including age, general condition based on American Society of Anesthesiologist physical status classification grade, age-Charlson Comorbidity Index, and disc degeneration, were worse in elderly group (p < 0.001). However, except for leg pain at 4 weeks after surgery, overall outcomes, including pain improvement, radiological change, operation time, blood loss, and hospital stay, were not different between the 2 groups. Furthermore, the rates of perioperative complications (9 patients [4.46%] in the young group and 3 patients [6.38%] in the elderly group, p = 0.578) and adverse events over the 3-year follow-up period (32 patients [15.84%] in the young group and 9 patients [19.15%] in the elderly group, p = 0.582) were comparable in the 2 groups.

CONCLUSION

Our findings suggest that TELD produces similar outcomes in both elderly and younger patients with a herniated disc in the lumbosacral region. TELD can be considered a safe option for appropriately selected elderly patients.

The Role and Clinical Outcomes of Endoscopic Spine Surgery of Treating Spinal Metastases; Outcomes of 29 Cases From 8 Countries

OBJECTIVE

We aim to report the outcomes and feasibility of endoscopic spine surgery used to treat symptomatic spinal metastases patients. This is the most extensive series of spinal metastases patients who underwent endoscopic spine surgery.

METHODS

A worldwide collaborative network group of endoscopic spine surgeons, named 'ESSSORG,' was established. Patients diagnosed with spinal metastases who underwent endoscopic spine surgery from 2012 to 2022 were retrospectively reviewed. All related patient data and clinical outcomes were gathered and analyzed before the surgery and the followtime period of 2 weeks, 1 month, 3 months, and 6 months.

RESULTS

A total of 29 patients from South Korea, Thailand, Taiwan, Mexico, Brazil, Argentina, Chile, and India, were included. The mean age was 59.59 years, and 11 of them were female. The total number of decompressed levels was 40. The technique was relatively equal (15 uniportal; 14 biportal). The average length of admission was 4.41 days. Of all patients with an American Spinal Injury Association Impairment Scale of D or lower before surgery, 62.06% reported having at least one recovery grade after the surgery. Almost all clinical outcomes parameters statistically significantly improved and maintained from 2 weeks to 6 months after the surgery. Few surgical-related complications (4 cases) were reported.

CONCLUSION

Endoscopic spine surgery is a valid option for treating spinal metastases patients as it could yield comparable results to other minimally invasive spine surgery techniques. As the aim is to improve the quality of life, this procedure is valuable and holds value in palliative oncologic spine surgery.

Clinical Outcomes of Selective Single-Level Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression of Multilevel Lumbar Spinal Stenosis and Risk Factors of Reoperation

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To investigate the usefulness of selective single-level lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) in patients with radiological multilevel lumbar spinal stenosis (LSS) and clarify the predictive factors of reoperation.

METHODS

A total of 128 patients who underwent LE-ULBD of radiological multilevel LSS were retrospectively examined. Single-level decompression was selected clinically and supplemented radiologically. Clinical outcomes were assessed with the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), numeric rating scale (NRS), and Macnab criteria (mean follow-up period, 28.6 months [range, 24-63 months]). Stenosis severity was classified as grades M (moderate) and S (severe) based magnetic resonance imaging findings. Multilevel LSS was classified as SS, SM, and MM according to the number of grade S levels.

RESULTS

The follow-up rate was 74.2%. All domains of the JOABPEQ and NRS significantly improved during follow-up. The Macnab outcome classification was "excellent" or "good" in 77.9% of the patients. The reoperation rate was 10.2%. None of the patients with unilateral symptoms required reoperation. The SS type was a significant risk factor of reoperation for multilevel LSS with bilateral symptoms. Additional LE-ULBD was performed for all the reoperation with the "excellent" or "good" results of the Macnab criteria in 69% of the patients.

CONCLUSIONS

Selective single-level LE-ULBD provided favorable results for multilevel LSS. However, information about the risks of reoperation for multilevel severe stenosis with bilateral symptoms should be shared between surgeons and patients.

Full-endoscopic foraminotomy in low-grade degenerative and isthmic spondylolisthesis: a patient-specific tailored approach

PURPOSE

To describe the surgical technique and methodology to successfully plan and execute an endoscopic foraminotomy in patients with isthmic or degenerative spondylolisthesis, according to each patient's unique characteristics.

METHODS

Thirty patients with degenerative or isthmic spondylolisthesis (SL) with radicular symptoms were included from March 2019 to September 2022. Treating physician registered patients' baseline and imaging characteristics, as well as preoperative back pain VAS, leg pain VAS and ODI. Subsequently, authors treated the included patients with an endoscopic foraminotomy according to a "patient-specific" tailored approach.

RESULTS

Nineteen patients (63.33%) had isthmic SL and 11 patients (36.67%) had degenerative SL. 75.86% of the cases had a Meyerding Grade 1 listhesis. One of the transforaminal foraminotomies with lateral recess decompression in degenerative SL had to be aborted because of intense osseous bleeding. Of the remaining 29 patients, one patient experienced recurrence of the sciatica pain that required subsequent reintervention and fusion. No other intraoperative or post-operative complications were observed. None of the patients developed post-operative dysesthesia. In 86.67% of the patients, the foraminotomy was implemented using a transforaminal approach. In the remaining 13.33% of the cases, an interlaminar contralateral approach was used. Lateral recess decompression was performed in half of the cases. Mean follow-up time was 12.69 months, reaching a maximum of 40 months in some patients. Outcome variables such as VAS for leg and back pain, as well as ODI, showed statistically significant reduction since the 3-month follow-up visit.

CONCLUSION

In the presented case series, endoscopic foraminotomy achieved satisfactory outcomes without sacrificing segmental stability. The proposed patient-specific "tailored" approach allowed to successfully design and execute the surgical strategy to perform an endoscopic foraminotomy through transforaminal or interlaminar contralateral approaches.

Uniportal versus biportal endoscopic spine surgery: a comprehensive review

INTRODUCTION

Endoscopic spine surgery techniques are minimally invasive alternatives to conventional open surgery for degenerative spinal diseases. Clinical studies and meta-analyses have proven the usefulness of uniportal full-endoscopic spine procedures. However, a steep learning curve is a critical barrier for endoscopic procedures. Recently, biportal endoscopic spine surgeries have been developed to make it easier for spine surgeons to learn and perform. Consequently, the biportal approach has gained popularity among aspiring endoscopic spine surgeons. This review compared the characteristics of uniportal and biportal surgeries to help spine surgeons perform endoscopic procedures more effectively.

AREA COVERED

The review analyzed English-language clinical literature in Core databases and compared uniportal and biportal endoscopic spine surgery techniques. Clinical studies have compared the technical principles of both techniques, and the authors suggested appropriate strategies for learning and practicing endoscopic procedures.

EXPERT OPINION

Uniportal, full-endoscopic spine surgery is a minimally invasive procedure that preserves muscles and uses a keyhole approach under local anesthesia. In contrast, biportal surgery is more familiar to a surgeon and can be performed more widely, although the keyhole approach is limited. Aspiring endoscopic spine surgeons can learn either method according to the surgeon's preference and the clinical situation.

Full-endoscopic trans-pars interarticularis approach for far lateral lumbar discectomy

PURPOSE

Surgical management of far lateral disc herniations remains challenging. Current transforaminal full-endoscopic approaches require non-visualized docking in the Kambin's triangle and have been associated with significant risk of inadvertent nerve injury. We develop a full-endoscopic approach based on reliable bony landmarks allowing for visualization of the exiting nerve root prior to the far lateral discectomy.

METHODS

The surgical details of a full-endoscopic trans-pars interarticularis approach for far lateral discectomy are described. These descriptions include high quality intraoperative images and important surgical pearls. A small patient cohort is presented to demonstrate feasibility and safety of the procedure.

RESULTS

We demonstrate the feasibility of this approach in 14 patients with a mean age of 59.5 ± 14.7 years. At a mean follow up of 21.9 ± 6.8 months, improvement of the visual analogue scale (VAS) for leg pain was 4.3 ± 1.0 resulting in minimally clinically important difference in 78.6% of the patients. The mean improvement in VAS for the back pain was 2.6 ± 0.8 and for Oswestry disability index (ODI) was 20.6 ± 5.3. Nuances of the trans-pars surgical techniques are presented in a patient with a right-sided L4-5 far lateral disc herniation. Preoperative imaging studies, steps of the surgical progression, and intraoperative views are described in detail.

CONCLUSION

Using the pars interarticularis as the bony target area allows for safe visualized access to the extraforaminal compartment of the exiting nerve root. This novel surgical technique has the potential benefit of decreasing inadvertent neural injury and subsequent postoperative dysesthesias.

Full-endoscopic technique mitigates obesity-related perioperative morbidity of minimally invasive lumbar decompression

PURPOSE

Obesity is associated with increased surgical complexity and postoperative complications in spine surgery. Minimally invasive procedures have been shown to lessen some of the increased risk in obese patients. This study investigated whether utilization of a working channel endoscope can further mitigate obesity-associated challenges in spinal surgery.

METHODS

A retrospective review of a single-surgeon database was conducted for all adult patients undergoing full-endoscopic unilateral laminotomies for bilateral decompression between November 2015 and March 2021. Data collected included body mass index, in operating room preparation time, procedure time, length of hospital stay, use of analgesics, complications, and quality of life measured by Oswestry Disability Index.

RESULTS

Our cohort included 174 patients. Of these, 74 (42.5%) were obese. The average age was 63.6 years. In-operating room preparation time was 70.0 ± 1.7 min for obese patients and 64.4 ± 1.5 min for non-obese patients (p = 0.02). There was no difference in operative time, durotomy rates or other perioperative complications between obese and non-obese patients. Hospital length of stay trended toward longer in the obese group, but did not reach significance. A greater percentage of obese patients were still using both narcotic and non-narcotic pain medications 2 weeks after surgery. There was no significant difference in functional outcomes between groups.

CONCLUSION

Full-endoscopic unilateral laminotomies for bilateral decompression are safe and effective in both non-obese and obese patients. The use of an endoscope can partially mitigate obesity-related morbidity in lumbar decompression. However, obesity is significantly related to increased postoperative analgesic use.

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.

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

STUDY DESIGN

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

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictors for hemostatic thrombin-gelatin matrix usage in spine surgery: a multicenter observational study

STUDY DESIGN

A prospective cohort study.

OBJECTIVES

Thrombin-gelatin matrix (TGM) is a rapid and potent hemostatic agent, but it has some limitations, including the cost and its preparation time. The purpose of this study was to investigate the current trend in the use of TGM and to identify the predictors for TGM usage in order to ensure its proper use and optimized resource allocation.

METHODS

A total of 5520 patients who underwent spine surgery in a multicenter study group within a year were included in the study. The demographic factors and the surgical factors including spinal levels operated, emergency surgery, reoperation, approach, durotomy, instrumented fixation, interbody fusion, osteotomy, and microendoscopy-assistance were investigated. TGM usage and whether it was routine or unplanned use for uncontrolled bleeding were also checked. A multivariate logistic regression analysis was used to identify predictors for unplanned use of TGM.

RESULTS

Intraoperative TGM was used in 1934 cases (35.0%), among which 714 were unplanned (12.9%). Predictors of unplanned TGM use were female gender (adjusted odds ratio [OR]: 1.21, 95% confidence interval [CI]: 1.02-1.43, p = 0.03), ASA grade ≥ 2 (OR: 1.34, 95% CI: 1.04-1.72, p = 0.02), cervical spine (OR: 1.55, 95% CI: 1.24-1.94, p < 0.001), tumor (OR: 2.02, 95% CI: 1.34-3.03, p < 0.001), posterior approach (OR: 1.66, 95% CI: 1.26-2.18, p < 0.001), durotomy (OR: 1.65, 95% CI: 1.24-2.20, p < 0.001), instrumentation (OR: 1.30, 1.03-1.63, p = 0.02), osteotomy (OR: 5.00, 2.76-9.05, p < 0.001), and microendoscopy (OR: 2.24, 1.84-2.73, p < 0.001).

CONCLUSIONS

Many of the predictors for unplanned TGM use have been previously reported as risk factors for intraoperative massive hemorrhaging and blood transfusion. However, other newly revealed factors can be predictors of bleeding that is technically challenging to control. While routine usage of TGM in these cases will require further justification, these novel findings are valuable for implementing preoperative precautions and optimizing resource allocation.

A 30-Year Worldwide Research Productivity of Scientific Publication in Full-Endoscopic Decompression Spine Surgery: Quantitative and Qualitative Analysis

Objective: The ever-growing number of articles related to full-endoscopic spine surgery published in the last few decades presents a challenge which is perplexing and time-consuming in identifying the current research status. The study aims to identify and analyze the most cited works related to full-endoscopic decompression spine surgery, compare the articles published by different publishers and area, and show the current publication status of full-endoscopic research.Methods: Using Bibliometrix, CiteSpace, and VOSviewer, we analyzed the bibliometric data selected from the Web of Science database between 1992 and 2022. Spine has the highest H-index with the most-cited journal in the field of full-endoscopic decompression spine surgery. China ranked as the most productive country, whereas the most cited with high H-index papers came from South Korea. For the author analysis, Yeung AT, Ruetten S, Hoogland T, Ahn Y, Choi G, and Mayer HM were the most impactful authors in the global and local citations. The most productive organization is Wooridul Spine Hospital.Conclusion: The bibliometric study showed a growing trend of research on full-endoscopic decompression spine surgery over the past 30 years. It has demonstrated that there is a significant increase in the number of authors, institutions, and internationally collaborated countries. However, the quality of studies is still low, and the lack of high-quality clinical evidence and the trend of general journal submissions has somewhat affected the quality of endoscopy journals in recent years.

The Role and Future of Endoscopic Spine Surgery: A Narrative Review

Many types of surgeries are changing from conventional to minimally invasive techniques. Techniques in spine surgery have also changed, with endoscopic spine surgery (ESS) becoming a major surgical technique. Although ESS has advantages such as less soft tissue dissection and normal structure damage, reduced blood loss, less epidural scarring, reduced hospital stay, and earlier functional recovery, it is not possible to replace all spine surgery techniques with ESS. ESS was first used for discectomy in the lumbar spine, but the range of ESS has expanded to cover the entire spine, including the cervical and thoracic spine. With improvements in ESS instruments (optics, endoscope, endoscopic drill and shaver, irrigation pump, and multiportal endoscopic), limitations of ESS have gradually decreased, and it is possible to apply ESS to more spine pathologies. ESS currently incorporates new technologies, such as navigation, augmented and virtual reality, robotics, and 3-dimentional and ultraresolution visualization, to innovate and improve outcomes. In this article, we review the history and current status of ESS, and discuss future goals and possibilities for ESS through comparisons with conventional surgical techniques.

Uniportal, Transforaminal Endoscopic Thoracic Discectomy: Review and Technical Note

Symptomatic thoracic disc herniations are a rare entity and their operative treatment is challenging. Open approaches, despite providing excellent access, are associated with significant access morbidity from thoracotomy, and this has led to an increased interest in minimally invasive techniques such as mini-open approach, thoracoscopic approach and the endoscopic approach. In this article, we describe the technical points for performing a transforaminal endoscopic thoracic discectomy and summarize its literature outcomes in the context of other minimally invasive approaches.

Current Indications for Spinal Endoscopic Surgery and Potential for Future Expansion

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

Full-endoscopic discectomy for thoracic disc herniations: a single-arm meta-analysis of safety and efficacy outcomes

INTRODUCTION

Surgical intervention is the treatment of choice in patients with thoracic disc herniation with refractory symptoms and progressive myelopathy. Due to high occurrence of complications from open surgery, minimally invasive approaches are desirable. Nowadays, endoscopic techniques have become increasingly popular and full-endoscopic surgery can be performed in the thoracic spine with low complication rates.

METHODS

Cochrane Central, PubMed, and Embase databases were systematically searched for studies that evaluated patients who underwent full-endoscopic spine thoracic surgery. The outcomes of interest were dural tear, myelopathy, epidural hematoma, recurrent disc herniation, and dysesthesia. In the absence of comparative studies, a single-arm meta-analysis was performed.

RESULTS

We included 13 studies with a total of 285 patients. Follow-up ranged from 6 to 89 months, age from 17 to 82 years, with 56.5% male. The procedure was performed under local anesthesia with sedation in 222 patients (77.9%). A transforaminal approach was used in 88.1% of the cases. There were no cases of infection or death reported. The data showed a pooled incidence of outcomes as follows, with their respective 95% confidence intervals (CI)-dural tear (1.3%; 95% CI 0-2.6%); dysesthesia (4.7%; 95% CI 2.0-7.3%); recurrent disc herniation (2.9%; 95% CI 0.6-5.2%); myelopathy (2.1%; 95% CI 0.4-3.8%); epidural hematoma (1.1%; 95% CI 0.2-2.5%); and reoperation (1.7%; 95% CI 0.1-3.4%).

CONCLUSION

Full-endoscopic discectomy has a low incidence of adverse outcomes in patients with thoracic disc herniations. Controlled studies, ideally randomized, are warranted to establish the comparative efficacy and safety of the endoscopic approach relative to open surgery.

Bibliographic Study and Meta-Analysis of Clinical Outcomes of Full-Endoscopic Spine Surgery for Painful Lumbar Spine Conditions

BACKGROUND

Full-endoscopic spine surgery (FESS) indications already cover degenerative, infectious, and neoplastic diseases. This study aimed to use a bibliometric search and meta-analysis of the highest-quality studies in the last 20 years to determine the quantity and quality of FESS research, geographic distribution, and the outcomes for lumbar conditions.

METHODS

Articles on FESS published from 2000 to 2022 were screened and assessed through Web of Science, PubMed, and Scopus. Also, databases were searched for longitudinal studies to pool in a meta-analysis of patients undergoing FESS for lumbar conditions. After stratifying the risk of bias and having collected the studies of the highest quality, we included the proportion of patients with a satisfactory outcome and intraoperative and postoperative adverse events after the analysis of lumbar spine conditions.

RESULTS

A total of 728 articles were identified by the bibliographic search. Between 2000 and 2021, the published articles increased 21-fold. Most were from China (70.15%), followed by South Korea (19.5%). Most were retrospective (68.3%) and regarding treatment of lumbar disease (86.4%). Fifty studies, including 34,828 patients, were pooled in the meta-analysis. More than 85% of patients experienced satisfactory improvement in each of different lumbar conditions. Major adverse events were <2%; recurrence and postoperative dysesthesia rates were within those reported for open or mini-invasive procedures.

CONCLUSIONS

This study may fill research gaps on FESS and lead to adequately designed studies. Our meta-analysis showed that FESS for lumbar diseases is a procedure with satisfactory outcomes and low rates of adverse events.

Identification of the Magna Radicular Artery Entry Foramen and Adamkiewicz System: Patient Selection for Open versus Full-Endoscopic Thoracic Spinal Decompression Surgery

BACKGROUND

Casually cauterizing the radicular magna during routine thoracic discectomy may have dire consequences.

METHODS

We performed a retrospective observational cohort study on patients scheduled for decompression of symptomatic thoracic herniated discs and spinal stenosis who underwent a preoperative computed tomography angiography (CTA) to assess the surgical risks by anatomically defining the foraminal entry level of the magna radicularis artery into the thoracic spinal cord and its relationship to the surgical level.

RESULTS

Fifteen patients aged 58.53 ± 19.57, ranging from 31 to 89 years, with an average follow-up of 30.13 ± 13.42 months, were enrolled in this observational cohort study. The mean preoperative VAS for axial back pain was VAS of 8.53 ± 2.06 and reduced to a postoperative VAS of 1.60 ± 0.92 (p < 0.0001) at the final follow-up. The Adamkiewicz was most frequently found at T10/11 (15.4%), T11/12 (23.1%), and T9/10 (30.8%). There were eight patients where the painful pathology was found far from the AKA foraminal entry-level (type 1), three patients with near location (type 2), and another four patients needing decompression at the foraminal (type 3) entry-level. In five of the fifteen patients, the magna radicularis entered the spinal canal on the ventral surface of the exiting nerve root through the neuroforamen at the surgical level requiring a change of surgical strategy to prevent injury to this important contributor to the spinal cord's blood supply.

CONCLUSIONS

The authors recommend stratifying patients according to the proximity of the magna radicularis artery to the compressive pathology with CTA to assess the surgical risk with targeted thoracic discectomy methods.

Full-endoscopic spine surgery diminishes surgical site infections - a propensity score-matched analysis

BACKGROUND CONTEXT

Surgical site infections (SSI) are one the most frequent and costly complications following spinal surgery. The SSI rates of different surgical approaches need to be analyzed to successfully minimize SSI occurrence.

PURPOSE

The purpose of this study was to define the rate of SSIs in patients undergoing full-endoscopic spine surgery (FESS) and then to compare this rate against a propensity score-matched cohort from the National Surgical Quality Improvement Program (NSQIP) database.

DESIGN

This is a retrospective multicenter cohort study using a propensity score-matched analysis of prospectively maintained databases.

PATIENT SAMPLE

One thousand two hundred seventy-seven non-instrumented FESS cases between 2015 and 2021 were selected for analysis. In the nonendoscopic NSQIP cohort we selected data of 55,882 patients.

OUTCOME MEASURES

The occurrence of any SSI was the primary outcome. We also collected any other perioperative complications, demographic data, comorbidities, operative details, history of smoking, and chronic steroid intake.

METHODS

All FESS cases from a multi-institutional group that underwent surgery from 2015 to 2021 were identified for analysis. A cohort of cases for comparison was identified from the NSQIP database using Current Procedural Terminology of nonendoscopic cervical, thoracic, and lumbar procedures from 2015 to 2019. Trauma cases as well as arthrodesis procedures, surgeries to treat pathologies affecting more than 4 levels or spine tumors that required surgical treatment were excluded. In addition, nonelective cases, and patients with wounds worse than class 1 were also not included. Patient demographics, comorbidities, and operative details were analyzed for propensity matching.

RESULTS

In the non-propensity-matched dataset, the endoscopic cohort had a significantly higher incidence of medical comorbidities. The SSI rates for nonendoscopic and endoscopic patients were 1.2% and 0.001%, respectively, in the nonpropensity match cohort (p-value <.011). Propensity score matching yielded 5936 nonendoscopic patients with excellent matching (standard mean difference of 0.007). The SSI rate in the matched population was 1.1%, compared to 0.001% in endoscopic patients with an odds ratio 0.063 (95% confidence interval (CI) 0.009-0.461, p=.006) favoring FESS.

CONCLUSIONS

FESS compares favorably for risk reduction in SSI following spinal decompression surgeries with similar operative characteristics. As a consequence, FESS may be considered the optimal strategy for minimizing SSI morbidity.

[Endoscopic treatment of mine-explosive spine injuries: 3 clinical cases and literature review]

Modern warfare is characterized by common mine-explosive injuries. The last ones are accompanied by multiple injuries, large area of damage and severe clinical status of victims.

OBJECTIVE

To demonstrate treatment of mine-explosive spinal injuries using modern minimally invasive endoscopic techniques.

MATERIAL AND METHODS

The authors present 3 victims with various mine-explosive injuries. Endoscopic removal of fragments from the lumbar and cervical spine was successful in all cases.

DISCUSSION

Most of victims with injuries of the spine and spinal cord do not require urgent surgery and can underwent surgical treatment after clinical stabilization. At the same time, minimally invasive techniques provide surgical treatment with minimal risk and earlier rehabilitation, as well as reduce the risk of infectious complications associated with foreign bodies.

CONCLUSION

Careful selection of patients for spinal video endoscopy will ensure positive outcomes. Minimization of iatrogenic postoperative injuries is especially important in patients with combined trauma. However, well-experienced surgeons should perform these procedures at the stage of specialized medical care.

Full Endoscopic Ligamentum Flavum Sparing Unilateral Laminotomy for Bilateral Recess Decompression: Surgical Technique and Clinical Results

OBJECTIVE

Interlaminar endoscopic spine surgery has been introduced and utilized for lumbar lateral recess decompression. We modified this technique and utilized it for bilateral lateral recess stenoses without significant central stenosis. Here we present the surgical details and clinical outcome of ligamentum flavum sparing unilateral laminotomy for bilateral recess decompression (ULBRD).

METHODS

Prospectively collected registry for full-endoscopic surgeries was reviewed retrospectively. One hundred eighty-two consecutive cases from a single center between September 2015 and March 2021 were reviewed and 57 of them whom underwent ULBRD were enrolled for analysis. Basic patient demographic data, perioperative details, surgeryrelated complications, and clinical outcome were reviewed. The detailed surgical technique is presented as well.

RESULTS

Among the 57 patients enrolled, 37 were males while the other 20 were females. The mean age was 58.53 ± 14.51 years, and a bimodal age distribution at the age of mid-fifties and mid-sixties or older was noted. The later age-peak was related to coexistence of degenerative scoliosis. The average operative time per lamina was 70.34 ± 20.51 minutes and mean length of stay was 0.56 ± 0.85 days. Four perioperative complications were reported (7.0%) and the overall reoperation rate at the index level within 1 year was 8.8%. The preoperative back/leg visual analogue scale scores and functional outcome scales including EuroQol-5 dimension questionnaire, Oswestry Disability Index presented significant improvement immediately after surgery and were maintained until final follow-up.

CONCLUSION

ULBRD for bilateral lateral recess stenoses without significant central stenosis resulted in good clinical outcomes with acceptably low perioperative complications rates. Sufficient decompression was achieved with the central ligamentum flavum being preserved.

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.

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.

Percutaneous Transforaminal Full-Endoscopic Removal of Neurinoma of the Fifth Lumbar Nerve Root With Intraoperative Neuromonitoring: A Case Report

Background

Technical achievements and surgical techniques improvement contribute to the expansion of the endoscopic spine surgery possibilities. However, today there are few reports about the use of percutaneous endoscopy in spinal tumor surgery. A case of percutaneous transforaminal endoscopic removal of the lumbar spinal nerve tumor with intraoperative neuromonitoring is presented.

Case Description

A 59-year-old female was complaining of a left shin and foot pain, weakness, and paresthesia. Preoperative magnetic resonance imaging (MRI) revealed a tumor (neurinoma) at the left L5-S1 intervertebral foramen. Transforaminal endoscopic removal of an extramedullary tumor from an 8-mm skin incision with intraoperative neuromonitoring was performed. Postoperative MRI revealed the signs of total resection of the tumor.

Conclusion

The presented case confirms that percutaneous endoscopic removal of lumbar spine intraforaminal neurinomas can be safe and effective.

Foundations in Spinal Endoscopy

Spinal endoscopy has revolutionized the way spine surgeons deliver minimally invasive care for appropriately selected patients. The evolution of endoscopy has been tumultuous since its beginnings as a "blind" percutaneous procedure to access the disk until the present state, in which complex decompressions and even fusions can be accomplished through subcentimeter incisions. Engineering has played a crucial role in this evolution with advances in optics, illumination, and instrumentation that have allowed surgeons to work safely and efficiently in smaller and smaller corridors. Finally, the adaptation of enhanced recovery after surgery protocols have complemented the benefits offered by spinal endoscopy to help patients return to the quality of life they seek through surgical intervention. In this article, we explore foundational elements of spinal endoscopy and look ahead to the future of this maturing field.

Innovations in Spinal Endoscopy

Innovations in spinal endoscopy technology and technique have broadened their applications during the past 10 years. Smaller outer-diameter working-channel endoscopes have permitted safe usage in the cervical spine for full endoscopic decompressions. Endoscopic fusions have now been widely reported, leveraging compatible instrumentation for disc preparation and expandable interbody grafts. This ultra-minimally invasive technique has also enabled the performance of fusion procedures in awake patients under monitored anesthesia care, affording speedier recovery and treatment options for those unable to undergo general anesthesia. Revision surgery after open or minimally invasive posterior discectomy or instrumentation can now be performed with endoscopic techniques, which often leverage the transforaminal approach to avoid scar tissue and adhesions. These procedures, among other endoscopic surgeries, are now being increasingly performed in ambulatory surgery centers, as safe outcomes, economic benefits to the healthcare system, and patients' desire to recover at home are becoming more apparent. Finally, the standardization of endoscopic terminology, which has long been a confounder to proper communication and education in this field, has recently been addressed by leading experts in a consensus document, which will serve as the foundation for future collaborative advancements.

Risk Factors for Poor Outcomes Following Minimally Invasive Discectomy: A Post Hoc Subgroup Analysis of 2-Year Follow-up Prospective Data

Objective

A post hoc subgroup analysis of prospectively collected data from a randomized controlled trial was conducted to identify risk factors related to poor outcomes in patients who underwent minimally invasive discectomy.

Methods

Patients were divided into satisfied and dissatisfied subgroups based on Oswestry Disability Index (ODI), visual analogue scale (VAS) back pain score (VAS-back) and leg pain score (VAS-leg) at short-term and midterm follow-up according to the patient acceptable symptom state threshold. Demographic characteristics, radiographic parameters, and clinical outcomes between the satisfied and dissatisfied subgroups were compared using univariate and multivariate analysis.

Results

A total of 222 patients (92.1%) completed 2-year follow-up, and the postoperative ODI, VAS-back, and VAS-leg were significantly improved after surgery as compared to preoperatively. Multivariate analysis indicated older age (p=0.026), lateral recess stenosis (p=0.046), and lower baseline ODI (p=0.027) were related to poor short-term functional improvement. Higher baseline VAS-back (p=0.048) was associated with poor short-term relief of back pain, while absence of decreased sensation (p=0.019) and far-lateral disc herniation (p=0.004) were associated with poorer short-term relief of leg pain. Lumbar facet joint osteoarthritis was identified as a risk factor for poor functional improvement (p=0.003) and relief of back pain (p=0.031). Disc protrusion (p=0.036) predicted poorer relief of back pain at midterm follow-up.

Conclusion

In this study, several factors were identified to be predictive of poor surgical outcomes following minimally invasive discectomy. (ClinicalTrials.gov number: NCT01997086).

Comparative study of the efficacy and safety of minimally invasive interlaminar full-endoscopic discectomy versus conventional microscopic discectomy in single-level lumbar herniated intervertebral disc (ENDO-F Trial): a multicenter, prospective, randomized controlled trial protocol

Background

Advances in minimally invasive surgery have expanded the indications for interlaminar full-endoscopic discectomy. Although the clinical outcomes for this approach may be equivalent to those of conventional microscopic discectomy, the supporting evidence is still based on small, single-center, prospective, and retrospective studies. Therefore, a multicenter randomized controlled trial is warranted.

Methods

This will be a prospective, multicenter, randomized controlled trial comparing the efficacy and safety of interlaminar full-endoscopic discectomy to those of conventional microscopic discectomy. The trial will enroll 100 participants with a lumbar disc herniation, 50 in each group. The primary outcome will be the Oswestry Disability Index (ODI) score at 12 months post-surgery. Secondary outcomes will be back and leg pain (visual analog scale); the ODI; the EuroQol-5-dimension score; patient satisfaction; and walking distance/time and time to return to daily activities post-surgery. Surgical outcomes will include postoperative drainage, operative time, duration of hospital stay, postoperative creatine kinase level as an indicator of muscle injury, and postoperative scarring. Postoperative magnetic resonance imaging, computed tomography, and simple radiography will be performed to evaluate radiographic outcomes between the two surgical approaches. Surgery-related complications and adverse effects will be evaluated as safety outcomes. A single assessor at each participating hospital, blinded to group allocation, will assess the enrolled participants at baseline, at 2 weeks, and at 3, 6, and 12 months postoperatively.

Discussion

This trial is designed to determine whether interlaminar full-endoscopic discectomy is clinically comparable to microscopic discectomy to treat lumbar disc herniations. All efforts will be made to reduce bias, including adequate sample size, blinded analyses, and multicenter prospective registration. The outcomes will inform practice, providing the evidence needed for using interlaminar full-endoscopic over microscopic discectomy by confirming the potential of this technique to improve patient satisfaction and clinical outcomes.

Trial registration: Clinical Research Information Service; cris.nih.go.kr. (KCT0006277); protocol version (v1, June 8, 2021).