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

Global Trends and Hotspots of Minimally Invasive Surgery in Lumbar Spinal Stenosis: A Bibliometric Analysis

Objective

The popularity of minimally invasive surgery for lumbar spinal stenosis (LSS) has been steadily increasing worldwide. This study aims to conduct a comprehensive bibliometric analysis to identify global trends and hotspots in the research related to this surgical approach.

Methods

Select articles related to the field that were retrieved from the Web of Science Core Collection (WoSCC) between January 1, 1993 and December 31, 2022. Visualization of networks and in-depth bibliometric analyses, including the number of publications, countries/regions, institutions, journals, authors, keywords, and references, were conducted using VOSviewer and CiteSpace software.

Results

A total of 1197 papers were identified over a three-decade period, with the highest production year being 2022, which saw 171 papers published. The most prolific countries/regions were the United States (279) and Harvard Medical School (59). Among journals, Spine (3289 citations) was the most cited, while World Neurosurgery (98 publications) had the highest number of publications. Lewandrowski, Kai-Uwe (29 publications) wrote the most articles, and Ahn, Y (239 citations) ranked first among cited authors. The most frequently used keyword was "discectomy", but recent years have shown a strong emergence of keywords such as "microendoscopic decompressive laminotomy", "foraminotomy" and "classification".

Conclusion

The United States and China have emerged as leaders in the field of minimally invasive surgery for LSS. Endoscopic spinal surgery is recognized as a critical approach, with ongoing research focused on indications, potential complications, minimally invasive anatomical approaches, and outcomes. Furthermore, there is a strong emphasis on optimizing the surgical process, which has become a trending and hot spot in current research. The improvement of surgical techniques is at the forefront of advancements in this field.

Three-dimensional analysis of puncture needle path through safety triangle approach PLD and design of puncture positioning guide plate

OBJECTIVE

In this study, the three-dimensional relationship between the optimal puncture needle path and the lumbar spinous process was discussed using digital technology. Additionally, the positioning guide plate was designed and 3D printed in order to simulate the surgical puncture of specimens. This plate served as an important reference for the preoperative simulation and clinical application of percutaneous laser decompression (PLD).

METHOD

The CT data were imported into the Mimics program, the 3D model was rebuilt, the ideal puncture line N and the associated central axis M were developed, and the required data were measured. All of these steps were completed. A total of five adult specimens were chosen for CT scanning; the data were imported into the Mimics program; positioning guide plates were generated and 3D printed; a simulated surgical puncture of the specimens was carried out; an X-ray inspection was carried out; and an analysis of the puncture accuracy was carried out.

RESULTS

(1) The angle between line N and line M was 42°~55°, and the angles between the line M and 3D plane were 1°~2°, 5°~12°, and 78°~84°, respectively; (2) As the level of the lumbar intervertebral disc decreases, the distance from point to line and point to surface changes regularly; (3) The positioning guide was designed with the end of the lumbar spinous process and the posterior superior iliac spine on both sides as supporting points. (4) Five specimens were punctured 40 times by using the guide to simulate surgical puncture, and the success rate was 97.5%.

CONCLUSION

By analyzing the three-dimensional relationship between the optimal puncture needle path and the lumbar spinous process, the guide plate was designed to simulate surgical puncture, and the individualized safety positioning of percutaneous puncture was obtained.

Relationship Between Types of Warming Devices and Surgical Site Infection in Patients Who Underwent Posterior Fusion Surgery Based on National Data

OBJECTIVE

Perioperative hypothermia can lead to various complications. Although various warming techniques have been used to prevent perioperative hypothermia, the effect of these techniques on surgical site infection (SSI) during posterior fusion surgery is unclear. The effects of warming devices on SSI rates were therefore analyzed using data complied by the Health Insurance and Review Assessment (HIRA) Service in Korea.

METHODS

This study included 5,406 patients in the HIRA Service database who underwent posterior fusion surgery during the years 2014, 2015, and 2017. Factors related to SSI in these patients, including warming devices, antibiotics, and transfusion, were analyzed.

RESULTS

The incidence of SSI was higher in patients who underwent forced air warming than in those who did not undergo active warming (odds ratio [OR], 1.73; p = 0.039), especially above 70 years old (OR, 4.11; p = 0.014). By contrast, the incidence of SSI was not significantly higher in patients who underwent device using conduction. Infection rates were higher in patients who received prophylactic antibiotics within 20 minutes before incision, than within 21 to 60 minutes (OR, 2.07; p = 0.001) and who received more blood transfusions (1 pint < volume ≤ 2 pint; OR, 1.75; p = 0.008, > 2 pint; OR, 2.73; p = 0.004).

CONCLUSION

SSI rates were higher in patients who underwent warming with forced air devices than with devices using conduction, as well as being higher in patients who older age, received blood transfusions and administered antibiotics within 20 minutes before incision. Devices using conduction have more advantages in preventing SSI than forced air warming device. In addition, the reduction of other risk factors for SSI may improve postoperative results.

Cost and Effectiveness of Percutaneous Endoscopic Interlaminar Discectomy versus Microscope-Assisted Tubular Discectomy for L5-S1 Lumbar Disc Herniation

OBJECTIVE

To assess the cost and effectiveness of percutaneous endoscopic interlaminar discectomy (PEID) and microscope-assisted tubular discectomy (MATD) for patients with L5/S1 lumbar disc herniation (LDH).

METHODS

The medical and financial records of patients diagnosed with L5/S1 LDH and who underwent either PEID or MATD from April 2021 to April 2022 were retrospectively collected. Demographic and baseline information, perioperative observational index, clinical outcomes, and inpatient costs were analyzed.

RESULTS

Sixty patients were included, with 30 patients in the PEID group and 30 patients in the MATD group. No significant difference was found in demographic and baseline information between the 2 groups (P > 0.05). The PEID group showed significantly shorter incision length, less intraoperative blood loss, shorter hospital stays, and higher intraoperative fluoroscopy frequency compared with the MATD group (P < 0.05). There were no significant differences in visual analog scale back/leg score, Oswestry Disability Index, and 36-Item Short-Form Survey score between PEID and MATD groups before the surgery and at any follow-up time points (P > 0.05). The total cost, surgery cost, and surgical instruments/materials cost were significantly higher in the PEID group compared with the MATD group (P < 0.05). In contrast, the drug and nursing costs were significantly higher in the MATD group than in the PEID group (P < 0.05).

CONCLUSIONS

PEID and MATD provide equivalent clinical efficacy and safety in treating LDH at L5/S1 segment within a 1-year follow-up. However, PEID is less invasive and MATD is less costly. No one surgical technique is superior in all aspects and patients should make decisions according to their top concern.

Surgical Strategy and Outcomes of Full Endoscopic Lumbar Discectomy for Recurrent Lumbar Disk Herniation Following a Previous Full Endoscopic Lumbar Discectomy

OBJECTIVE

Recurrent lumbar disc herniation (RLDH) cannot be prevented after full endoscopic lumbar discectomy (FELD), and the optimal surgical treatment for RLDH after FELD remains controversial. The aim of the study was to suggest a surgical strategy for FELD to treat RLDH following a previous FELD and to present surgical outcomes.

METHODS

Between February 2015 and March 2022, 68 patients with RLDH were surgically treated with FELD retrospectively. An original approach was suggested for the treatment of early recurrence (24 h-2 weeks). The full endoscopic transforaminal technique (FETD) was considered for patients requiring local anesthesia, and in RLDH with FETD indications or FEID technological difficulties. The full endoscopic interlaminar technique (FEID) was chosen in RLDH with FEID indications. Both FEID and FETD were suitable if no FEID or FETD technological difficulties existed. Clinical efficacy was evaluated using the visual analog scale (VAS) score, Oswestry disability index (ODI), and modified MacNab criteria. Postoperative follow-up data at 24 h, 3 months, and final-follow-up were recorded. Operation time and clinical outcomes were assessed with t test. p-value < 0.05 was considered statistically significant.

RESULTS

All 68 patients had an average follow-up time of 23.8 months (range, 6-76 months). In the 13 cases of early recurrence, the operation time (32.30 ± 9.67 vs. 58.00 ± 6.16 min) in the original surgical approach group was shorter than that in the changing surgical approach group (p < 0.05). In the 28 cases of L4/5 FETD recurrence (>2 weeks), the operation time (66.17 ± 12.18 vs. 53.60 ± 5.45 min) in the FETD group was more than that in the FEID group (p < 0.05). In the 22 cases of L5S1 recurrence (>2 weeks), the operation time (55.75 ± 8.79 vs. 79.33 ± 6.65 min) in the FEID group was shorter than in the FETD group (p < 0.05). The postoperative VAS and ODI scores at 24 h, 3 months, and final-follow up were all significantly improved, compared with their preoperative counterparts (p < 0.05). Based on the modified MacNab criteria, 88.23% of patients showed excellent or good results. Re-recurrence occurred in three patients at 3 months. No surgical complications were observed in any of the 68 cases.

CONCLUSION

FELD is a safe and effective treatment option for RLDH with previous FELD. For early recurrence, the original approach was suggested. Both FEID and FETD were effective and safe for recurrence (>2 weeks), but FEID seemed more efficient for L4/5 RLDH after previous FETD and for L5S1 RLDH.

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.

Ambulatory uniportal versus biportal endoscopic unilateral laminotomy with bilateral decompression for lumbar spinal stenosis-cohort study using a prospective registry

BACKGROUND

Endoscopic spine surgery has been established as a practical, minimally invasive technique for decompression in patients with lumbar spinal stenosis. However, there remains a paucity of studies prospective cohort study comparing uniportal lumbar endoscopic unilateral laminotomy with bilateral decompression and unilateral biportal endoscopic unilateral laminotomy with bilateral decompression with open spinal decompression-both viable techniques with satisfactory clinical outcomes in the treatment of lumbar spinal stenosis.

OBJECTIVE/AIM

To compare the efficacy of UPE and BPE lumbar decompression surgery for patients with lumbar spinal stenosis.

METHODS

A prospective registry of patients who had undergone spinal decompression for lumbar stenosis via UPE or BPE under a single fellowship trained spine surgeon was studied. Baseline characteristics, initial clinical presentation, and operative details including complications were recorded for all included patients. Clinical outcomes, such as visual analogue scale and Oswestry Disability Index, were recorded at preoperative, immediate postoperative, 2-week, 3-, 6-, and 12-month follow-up periods.

RESULTS

A total of 62 patients underwent endoscopic decompression surgery for lumbar spinal stenosis (29 UPE, 33 BPE). No significant baseline differences were found between uniportal and biportal decompression, when comparing operative duration (130 vs. 140 min; p = 0.30), intraoperative blood loss (5.4 vs. 6mLs; p = 0.05), and length of hospital stay (23.6 vs. 20.3 h; p = 0.35). Two patients (7%) who underwent uniportal endoscopic decompression required conversion to open surgery due to inadequate decompression. Intraoperative complication rates were significantly higher in the UPE group (13.4% vs. 0%, p < 0.05). VAS score (leg & back) and ODI improved significantly (p < 0.001) in both endoscopic decompression groups across all follow-up time points, with no appreciable statistical differences between both groups.

CONCLUSION

UPE has the same efficacy as BPE in the treatment of lumbar spinal stenosis. While UPE surgery enjoys added aesthetic benefits of only one wound, BPE had potentially lower risks of intraoperative complication, inadequate decompression, and conversion to open surgery during early period of learning curve.

Development of an Endoscopic Spine Surgery Program: Overview and Basic Considerations for Implementation

Endoscopic spine surgery (ESS) is an innovative technique allowing for minimally invasive, direct visualization of spinal abnormalities. The growth of ESS in the United States has been stunted by high start-up costs, low reimbursement rates, and the steep learning curve associated with mastering endoscopic techniques. Hergrae, we describe the current state and future direction of ESS and provide key action items for ESS program implementation.

Retrospective Case Control Study: Clinical and Computer Tomographic Fusion and Subsidence Evaluation for Single Level Uniportal Endoscopic Posterolateral Approach Transforaminal Lumbar Interbody Fusion Versus Microscopic Minimally Invasive Transforaminal Interbody Fusion

STUDY DESIGN

Retrospective comparative study.

OBJECTIVE

Assessment of difference in clinical and computer tomographic outcomes between the 2 cohorts.

METHODS

Computer tomographic evaluation by Bridwell's grade, Kim's stage, Kim's subsidence grade and clinical evaluation by VAS, ODI and McNab's criteria on both cohorts.

RESULTS

33 levels of Endo-TLIF and 22 levels of TLIF were included, with a mean follow up of 14.3 (10-24) and 22.9 (13-30) months respectively. Both Endo-TLIF and TLIF achieved significant improvement of pain and ODI at post-operative 4 week, 3 months and at final follow up with VAS 4.39 ± 0.92, 5.27 ± 1.16 and 5.73 ± 1.21in Endo-TLIF and 4.55 ± 1.16, 5.05 ± 1.11 and 5.50 ± 1.20 in TLIF respectively and ODI at post-operative 1 week, 3 months and final follow up were 43.15 ± 6.57, 49.27 ± 8.24 and 51.73 ± 9.09 in Endo-TLIF and 41.73 ± 7.98, 46.18± 8.46 and 49.09 ± 8.98 in TLIF respectively, P < 0.05. Compared to TLIF, Endo-TLIF achieved better VAS with 0.727 ± 0.235 at 3 months and 0.727 ± 0.252 at final follow up and better ODI with 3.88 ± 1.50 at 3months and 3.42 ± 1.63 at final follow up, P < 0.05. At 6 months radiological evaluation comparison of the Endo-TLIF and TLIF showed significant with more favorable fusion rate in Endo-TLIF of -0.61 ± 0.12 at 6 months and -0.49 ± 0.12 at 1 year in Bridwell's grading and 0.70 ± 0.15 at 6 months and 0.56 ± 0.14 at 1 year in Kim's stage.There is less subsidence of 0.606 ± 0.18 at 6 months and -0.561 ± 0.20 at 1 year of Kim's subsidence grade, P < 0.05.

CONCLUSION

Application of single level uniportal endoscopic posterolateral lumbar interbody fusion achieved better clinical outcomes and fusion rate with less subsidence than microscopic minimally invasive transforaminal lumbar interbody fusion in mid-term evaluation for our cohorts of patients.

Transforaminal Versus Interlaminar Endoscopic Lumbar Discectomy for Lumbar Disc Herniation: A Systematic Review and Meta-Analysis

STUDY DESIGN

Meta-analysis and systematic review.

OBJECTIVE

This study aims to investigate and compare patient-reported outcomes, perioperative data, and complications between 2 common endoscopic approaches for lumbar disc herniation: transforaminal and interlaminar endoscopic lumbar discectomy, by published high-quality evidence.

METHODS

Electronic databases were searched for reported outcomes following TELD and IELD. Oswestry Disability Index (ODI), visual analog scale of back (VASB) and leg pain (VASL), and MacNab criteria were evaluated. Operative time, hospital stays, blood loss, radiation exposure, and complications were investigated. Odds ratio (OR) and mean differences (MD) with 95% confidence intervals (CI) were calculated using random and fixed-effect models.

RESULTS

Total of 1948 patients from 18 studies were included, consisting of 1006 patients (51.6%) in TELD group and 942 (48.4%) patients in IELD group. TELD had better improvement of postoperative ODI (MD = 1.26; 95% CI: .07-2.16; P = .04), postoperative VASB (MD = -.23; 95% CI: -.40 to -.05; P = .01) and last follow-up VASB (MD = -.25; 95% CI: -.41 to -.09; P = .002), but with longer operative time (MD = 10.1 min; 95% CI: 1.925-18.77; P < .00001) and more fluoroscopic time (SMD = 4.12; 95% CI: 3.22-5.03; P < .00001), especially in L5-S1 operation. Bed rest time was significantly longer following IELD, with no difference in VASL, hospital stays, or complication.

CONCLUSION

We found comparable clinical outcomes in terms of ODI, VAS, patient satisfaction, hospital stays, and complication between both techniques. TELD required more radiation exposure and longer operative time at L5-S1 level than IELD. Our study provided results to help consider appropriate approaches for selected patients and informed consent of benefits from each approach.

Remodeling of Epidural Fluid Hematoma after Uniportal Lumbar Endoscopic Unilateral Laminotomy with Bilateral Decompression: Comparative Clinical and Radiological Outcomes with a Minimum Follow-up of 2 Years

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To evaluate the clinical and radiological effects of epidural fluid hematoma in the medium term after lumbar endoscopic decompression.

OVERVIEW OF LITERATURE

There is limited literature comparing the effect of postoperative epidural fluid hematoma after uniportal endoscopic decompression.

METHODS

Magnetic resonance imaging (MRI) and clinical evaluation were performed for patients with single-level uniportal endoscopic lumbar decompression with a minimum follow-up of 2 years.

RESULTS

A total of 126 patients were recruited with a minimum follow-up of 26 months. The incidence of epidural fluid hematoma was 27%. Postoperative MRI revealed a significant improvement in the postoperative dura sac area at postoperative day 1 and at the upper endplate at 6 months in the hematoma cohort (39.69±15.72 and 26.89±16.58 mm2) as compared with the nonhematoma cohort (48.92±21.36 and 35.1±20.44 mm2), respectively (p <0.05); and at the lower endplate on postoperative 1 day in the hematoma cohort (51.18±24.69 mm2) compared to the nonhematoma cohort (63.91±27.92 mm2) (p <0.05). No significant difference was observed in the dura sac area at postoperative 1 year in both cohorts. The hematoma cohort had statistically significant higher postoperative 1-week Visual Analog Scale (VAS; 3.32±0.68) pain and Oswestry Disability Index (ODI; 32.65±5.56) scores than the nonhematoma cohort (2.99±0.50 and 30.02±4.84, respectively; p <0.05). No significant difference was found at the final follow-up VAS, ODI, and MRI dura sac area.

CONCLUSIONS

Epidural fluid hematoma is a common early postoperative MRI finding in lumbar endoscopic unilateral laminotomy with bilateral decompression. Conservative management is the preferred treatment option for patients who do not have a neurological deficit. Symptoms last only a few days and are self-limiting. A common endpoint is a remodeled fluid hematoma and the subsequent expansion of the dura sac area.

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.

Analysis of curative effect of percutaneous coaxial large channel endoscopic lumbar interbody fusion in the treatment of degenerative lumbar spinal stenosis

Objective

To investigate the clinical efficacy and technical points of Percutaneous Coaxial Large-channel Endoscopic Lumbar Interbody Fusion (PCLE-LIF) in the treatment of degenerative lumbar spinal stenosis.

Methods

The clinical data of patients with single-segment degenerative lumbar spinal stenosis who underwent PCLE-LIF surgery from January 2019 to June 2021 were retrospectively analyzed. Surgery-related data included symptom duration, operation time, hospital stay, and complication rate. Functional score data included low back pain and lower extremity pain VAS score, ODI score, and MacNab criteria were used to evaluate clinical effects. The Brantigan criteria were used to evaluate the interbody fusion.

Results

There were 62 patients in this group, including 35 males and 27 females. The surgical sites were all lower lumbar spine, including 35 cases of lumbar L4/5 and 27 cases of L5/S1. The length of hospital stay was 7.7 ± 1.4 days. All patients were followed up regularly for 1 year. The interbody fusion rate was 93.5% at 1 year after operation. There were 2 cases of numbness, 2 cases of nerve edema and pain, 1 case of cage displacement, and 1 case of pedicle screw loosening. The complication rate was 9.6%. The VAS scores of low back pain 1 day before surgery, 3 days, 3 months and 1 year after surgery were 4.48 ± 1.06, 0.84 ± 0.81, 0.40 ± 0.56, 0.39 ± 0.69, and the VAS of lower extremity pain at each time point of appeal were 5.58 ± 0.98, 0.91 ± 0.58, 0.31 ± 0.46, 0.19 ± 0.40. The ODI scores at 1 day before surgery, 3 months and 1 year after surgery were 60.01 ± 6.21, 15.58 ± 2.84, 8.82 ± 2.15. The ODI scores and VAS scores of low back pain and lower extremity pain at each follow-up time point after operation were significantly lower than those before operation (p < 0.05). The 1-year follow-up after operation was evaluated by the modified MacNab standard, and the results were excellent in 36 cases, good in 23 cases, fair in 3 cases, and poor in 0 cases, with an excellent and good rate of 95.2%.

Conclusion

Percutaneous coaxial large-channel endoscopic lumbar interbody fusion in the treatment of degenerative lumbar spinal stenosis has good short-term efficacy and high safety, and is worthy of popularization.

Comparison of the Clinical Efficacy of Transforaminal Endoscopy and Microtubular Technology for the Treatment of Lumbar Dumbbell-Shaped Tumors

OBJECTIVE

To analyze differences in feasibility and efficacy between the paravertebral approach and microtubular tumorectomy (PAMT) or percutaneous transforaminal endoscopic tumorectomy (PTET) for the treatment of lumbar dumbbell-shaped tumors.

METHODS

Clinical data of dumbbell-shaped lumbar tumors in patients treated with PAMT or PTET in our hospital between June 2015 and November 2020 were retrospectively analyzed. The gross total resection (GTR) rate, operation time, estimated blood loss, postoperative hospital stay (PHS), postoperative neurological function, and spinal stability were compared between the 2 surgical methods. Neurological improvement was assessed using the pain visual analogue scale (VAS) and the Japanese Orthopaedic Association (JOA) score.

RESULTS

Fifteen cases of GTR (93.8%) and 1 case of subtotal resection were included in the PTET group, whilst all 18 patients in the PAMT group achieved GTR. There was no significant difference in the GTR rate, operation time, and PHS between the PAMT and PTET groups. The estimated blood loss was significantly lower in the PTET group than in the PAMT group. At the last follow-up, there was no significant difference in the VAS or JOA scores between PTET and PAMT. No tumor recurrence or spinal instability was observed in either group during the follow-up period.

CONCLUSION

Both PAMT and PTET can achieve Eden type III-IV lumbar 1-stage tumor resection without additional spinal internal fixation due to reduced muscle, ligament, and facet joint damage. No lumbar instability and tumor recurrence occurred, and neurological function was improved.

Assessing the Learning Process of Transforaminal Endoscopic Discectomy for Sciatica

OBJECTIVE

Percutaneous transforaminal endoscopic discectomy (PTED) is gaining popularity by both surgeons and patients as a less invasive treatment option for sciatica. Concerns, however, exist for its learning curve. No previous study has assessed the learning process of PTED. Hereby we present the learning process of 3 surgeons learning PTED.

METHODS

This analysis was conducted alongside a multicenter randomized controlled trial. After attending a cadaveric workshop, 3 spine-dedicated surgeons started performing PTED, initially under the supervision of a senior surgeon. After each 5 cases, and up to case 20, the learning process was evaluated using the validated questionnaires (objective structured assessment of technical skills [OSATS], global operative assessment of laparoscopic skills [GOALS]) and a 10-step checklist specifically developed for PTED.

RESULTS

In total, 3 learning curve surgeons performed a total of 161 cases. Based on self-assessment, surgeons improved mostly in the domains "time and motion," "respect for tissue," and "knowledge and handling of instruments." Learning curve surgeons were more able to detect differences in performances on the OSATS than the senior surgeon. Based on the GOALS, the biggest improvements could be seen in "depth-perception" and "autonomy." Based on the 10-item specific checklist, all surgeons performed all 10 steps by case 10, while only 1 surgeon performed all steps adequately by case 15.

CONCLUSION

Based on these study results, PTED appears to be successfully adopted stepwise by 3 spine-dedicated surgeons. From 15 cases on, most steps are performed adequately. However, more cases might be necessary to achieve good clinical results. Validated tools are needed to determine the cutoff when a surgeon should be able to perform PTED independently.

Navigation Techniques in Endoscopic Spine Surgery

Endoscopic spine surgery (ESS) advances the principles of minimally invasive surgery, including minor collateral tissue damage, reduced blood loss, and faster recovery times. ESS allows for direct access to the spine through small incisions and direct visualization of spinal pathology via an endoscope. While this technique has many applications, there is a steep learning curve when adopting ESS into a surgeon's practice. Two types of navigation, optical and electromagnetic, may allow for widespread utilization of ESS by engendering improved orientation to surgical anatomy and reduced complication rates. The present review discusses these two available navigation technologies and their application in endoscopic procedures by providing case examples. Furthermore, we report on the future directions of navigation within the discipline of ESS.

Full-Endoscopic versus Minimally Invasive Lumbar Interbody Fusion for Lumbar Degenerative Diseases : A Systematic Review and Meta-Analysis

Objective

Although full-endoscopic lumbar interbody fusion (Endo-LIF) has been tried as the latest alternative technique to minimally invasive transforaminal lumbar interobody fusion (MIS-TLIF) since mid-2010, the evidence is still lacking. We compared the clinical outcome and safety of Endo-LIF to MIS-TLIF for lumbar degenerative disease.

Methods

We systematically searched electronic databases, including PubMed, EMBASE, and Cochrane Library to find literature comparing Endo-LIF to MIS-TLIF. The results retrieved were last updated on December 11, 2020. The perioperative outcome included the operation time, blood loss, complication, and hospital stay. The clinical outcomes included Visual analog scale (VAS) of low back pain and leg pain and Oswestry disability index (ODI), and the radiological outcome included pseudoarthosis rate with 12-month minimum follow-up.

Results

Four retrospective observational studies and one prospective observational study comprising 423 patients (183 Endo-LIF and 241 MIS-TLIF) were included, and the pooled data analysis revealed low heterogeneity between studies in our review. Baseline characteristics including age and sex were not different between the two groups. Operation time was significantly longer in Endo-LIF (mean difference [MD], 23.220 minutes; 95% confidence interval [CI], 10.669–35.771; p=0.001). However, Endo-LIF resulted in less perioperative blood loss (MD, -144.710 mL; 95% CI, 247.941–41.478; p=0.023). Although VAS back pain at final (MD, -0.120; p=0.586), leg pain within 2 weeks (MD, 0.005; p=0.293), VAS leg pain at final (MD, 0.099; p=0.099), ODI at final (MD, 0.141; p=0.093) were not different, VAS back pain within 2 weeks was more favorable in the Endo-LIF (MD, -1.538; 95% CI, -2.044 to -1.032; p<0.001). On the other hand, no statistically significant group difference in complication rate (relative risk [RR], 0.709; p=0.774), hospital stay (MD, -2.399; p=0.151), and pseudoarthrosis rate (RR, 1.284; p=0.736) were found.

Conclusion

Relative to MIS-TLIF, immediate outcomes were favorable in Endo-LIF in terms of blood loss and immediate VAS back pain, although complication rate, mid-term clinical outcomes, and fusion rate were not different. However, the challenges for Endo-LIF include longer operation time which means a difficult learning curve and limited surgical indication which means patient selection bias. Larger-scale, well-designed study with long-term follow-up and randomized controlled trials are needed to confirm and update the results of this systematic review.

Treatment of Calcified Lumbar Disc Herniation by Intervertebral Foramen Remolding: A Retrospective Study

Purpose

This study aimed to investigate the use of the percutaneous intervertebral foramen lens technology for secondary molding of the intervertebral foramen in the treatment of calcified lumbar discs.

Methods

The study included 104 patients who were divided into two groups. Group A comprised 50 patients with calcified lumbar disc herniation and group B comprised 54 patients with non-calcified lumbar disc herniation diagnosed by computed tomography and magnetic resonance imaging. Patients underwent a percutaneous endoscopic lumbar discectomy at our hospital from January 1, 2017, to December 31, 2019. Demographic characteristics before the surgery and perioperative outcomes were retrospectively reviewed. The treatment outcome was analyzed using the numerical rating scale (NRS) score, Oswestry Disability Index (ODI) score, and modified Macnab criteria.

Results

Patients in groups A and B showed significant improvement in both the NRS and ODI scores after the surgery and maintained relatively low ODI and NRS scores during subsequent follow-ups. According to the evaluation under the modified MacNab standard, the good–excellent rate of clinical efficacy was 94% in group A and 92.6% in group B at the 3 month follow-up. In group A, one patient developed neck pain during the surgery, which was diagnosed as spinal hypertension syndrome, and the surgery was suspended until the patient’s condition improved. No similar complications occurred in group B. In both the groups, no patient reported any dural leak, infection, or other related complications.

Conclusion

The use of transforaminal remolding technology can significantly improve the symptoms and dysfunction of patients with calcified and non calcified lumbar disc herniation. There are few intraoperative and postoperative complications and have little impact on vertebral stability. It can provide a reference for the treatment of special types of lumbar disc herniation.

A one-step foraminoplasty via a large trephine in percutaneous endoscopic transforaminal discectomy for the treatment of lumbar disc herniation

Background

Transforaminal percutaneous endoscopic lumbar discectomy (PELD) is a widely used basic technique for lumbar disc herniation (LDH) with advantages including causing less trauma and fast recovery. The secure, efficient, and rapid enlargement of the intervertebral foramen is a key step in PELD procedures. However, the conventional multi-step trephine system for foraminoplasty involves complicated surgical procedures. In this study, we reported an improved one-step foraminoplasty via a large trephine with simplified surgical procedures, reduced radiation exposure, and shortened operative time.

Methods

70 LDH patients who underwent PELD were retrospectively reviewed in this study. The conventional multi-step trephine system was used for foraminoplasty in 35 patients in the multi-step (MS) group, and the single large trephine was used in the other 35 patients in the one-step (OS) group. Indicators including the operative time, the time to establish the working cannula, intraoperative fluoroscopy times, the radiation dose, and postoperative complications were compared between the MS and OS group.

Results

The operative time and the time to establish the working cannula in the OS group was significantly shorter than that in the MS group (P < 0.01); intraoperative fluoroscopy times and the radiation dose in the OS group were significantly smaller than those in the MS group (P < 0.01). There was no statistical difference in the incidence of postoperative complications between the two groups (P > 0.05). The postoperative VAS scores and ODI scores (2 days and 3 months after the surgery) were significantly lower than the preoperative scores in both groups (P < 0.01), and there was no statistical difference in VAS scores or ODI scores between the two groups at the same time points (P > 0.05).

Conclusions

The one-step foraminoplasty via a single large trephine is an optimized technique evolving from the conventional multi-step foraminoplasty, showing significant superiority in simplified operation, shorted operative time, and reduced radiation exposure.

Usefulness of 3D CT/MRI Fusion Imaging for the Evaluation of Lumbar Disc Herniation and Kambin's Triangle

Study design: Prospective study. Objective: The aim of this study is to visualize the morphology of a lumbar herniated disc and Kambin’s triangle in three dimensions (3D) based on preoperative CT/MRI fusion images. Methods: CT/MRI fusion images of 23 patients (10 males and 13 females; mean age 58.2 years) were used to evaluate Kambin’s triangle, which is created between the superior articular process (SAP), exiting nerve root (ENR), inferiorly by the superior endplate of the lower lumbar vertebra and dural canal medially at 60 degree and 45 degree endoscopic approach angles. The percentage of the safe usage of transforaminal endoscopic approach was evaluated to utilize a 5 mm dilater without partial facet resection in the fusion image. The 3D lumbar nerve root sleeve angulation (3DNRA), which is the angle between the axis of the thecal sac and the nerve root sleeve, was calculated. The herniated discs were also visualized in the CT/MRI fusion image. Results: The 3DNRA became smaller from L2 to S1. The L2 3DNRA was statistically larger than those of the other root, and the S1 3DNRA was significantly smaller than the others (p < 0.05). (L2, 41.0°; L3, 35.6°; L4, 36.4°; L5, 33.9°; and S1, 23.2°). The SAP-ENR distance at 60° was greatest at L4/5 (5.9 mm). Possible needle passages at 60° to each disc level were 89.1% at L2/3, 87.0% at L3/4 and 84.8% at L4/5. However, the safe 5 mm dilater passage at 60° without bony resection to each disc level were 8.7% at L2/3, 28.3% at L3/4 and 37.0% at L4/5. The 60° corridor at L2/3 was the narrowest (p < 0.01). All herniated discs were visualized in the fusion image and the root compression site was clearly demonstrated especially with foraminal/extraforaminal herniations. Conclusion: The 3D lumbar CT/MRI fusion image enabled a combined nerve-bony assessment of Kambin’s triangle and herniated disc. A fully endoscopic 5 mm dilater may retract the exiting nerve root in more than 60% of total cases. This new imaging technique could prove to be very useful for the safety of endoscopic lumbar disc surgery.

Spine Surgery Assisted by Augmented Reality: Where Have We Been?

This present systematic review examines spine surgery literature supporting augmented reality (AR) technology and summarizes its current status in spinal surgery technology. Database search strategies were retrieved from PubMed, Web of Science, Cochrane Library, Embase, from the earliest records to April 1, 2021. Our review briefly examines the history of AR, and enumerates different device application workflows in a variety of spinal surgeries. We also sort out the pros and cons of current mainstream AR devices and the latest updates. A total of 45 articles are included in our review. The most prevalent surgical applications included are the augmented reality surgical navigation system and head-mounted display. The most popular application of AR is pedicle screw instrumentation in spine surgery, and the primary responsible surgical levels are thoracic and lumbar. AR guidance systems show high potential value in practical clinical applications for the spine. The overall number of cases in AR-related studies is still rare compared to traditional surgical-assisted techniques. These lack long-term clinical efficacy and robust surgical-related statistical data. Changing healthcare laws as well as the increasing prevalence of spinal surgery are generating critical data that determines the value of AR technology.

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).

Remodeling Pattern of Spinal Canal after Full Endoscopic Uniportal Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression: One Year Repetitive MRI and Clinical Follow-Up Evaluation

Objective: There is limited literature on repetitive postoperative MRI and clinical evaluation after Uniportal Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression. Methods: Clinical visual analog scale, Oswestry Disability Index, McNab’s criteria evaluation and MRI evaluation of the axial cut spinal canal area of the upper end plate, mid disc and lower end plate were performed for patients who underwent single-level Uniportal Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression. From the evaluation of the axial cut MRI, four types of patterns of remodeling were identified: type A: continuous expanded spinal canal, type B: restenosis with delayed expansion, type C: progressive expansion and type D: restenosis. Result: A total of 126 patients with single-level Uniportal Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression were recruited with a minimum follow-up of 26 months. Thirty-six type A, fifty type B, thirty type C and ten type D patterns of spinal canal remodeling were observed. All four types of patterns of remodeling had statistically significant improvement in VAS at final follow-up compared to the preoperative state with type A (5.59 ± 1.58), B (5.58 ± 1.71), C (5.58 ± 1.71) and D (5.27 ± 1.68), p < 0.05. ODI was significantly improved at final follow-up with type A (49.19 ± 10.51), B (50.00 ± 11.29), C (45.60 ± 10.58) and D (45.60 ± 10.58), p < 0.05. A significant MRI axial cut increment of the spinal canal area was found at the upper endplate at postoperative day one and one year with type A (39.16 ± 22.73; 28.00 ± 42.57) mm2, B (47.42 ± 18.77; 42.38 ± 19.29) mm2, C (51.45 ± 18.16; 49.49 ± 18.41) mm2 and D (49.10 ± 23.05; 38.18 ± 18.94) mm2, respectively, p < 0.05. Similar significant increment was found at the mid-disc at postoperative day one, 6 months and one year with type A (55.16 ± 27.51; 37.23 ± 25.88; 44.86 ± 25.73) mm2, B (72.83 ± 23.87; 49.79 ± 21.93; 62.94 ± 24.43) mm2, C (66.85 ± 34.48; 54.92 ± 30.70; 64.33 ± 31.82) mm2 and D (71.65 ± 16.87; 41.55 ± 12.92; 49.83 ± 13.31) mm2 and the lower endplate at postoperative day one and one year with type A (49.89 ± 34.50; 41.04 ± 28.56) mm2, B (63.63 ± 23.70; 54.72 ± 24.29) mm2, C (58.50 ± 24.27; 55.32 ± 22.49) mm2 and D (81.43 ± 16.81; 58.40 ± 18.05) mm2 at postoperative day one and one year, respectively, p < 0.05. Conclusions: After full endoscopic lumbar decompression, despite achieving sufficient decompression immediately postoperatively, varying severity of asymptomatic restenosis was found in postoperative six months MRI without clinical significance. Further remodeling with a varying degree of increment of the spinal canal area occurs at postoperative one year with overall good clinical outcomes.

A Narrative Review of Uniportal Endoscopic Lumbar Interbody Fusion: Comparison of Uniportal Facet-Preserving Trans-Kambin Endoscopic Fusion and Uniportal Facet-Sacrificing Posterolateral Transforaminal Lumbar Interbody Fusion

Uniportal endoscopic lumbar interbody fusion aims to achieve the bony union of 2 lumbar segments through cage insertion using full spinal endoscopy. Endoscopic fusion can adjust foraminal height and disc height, improve alignment, and minimize collateral soft tissue damage during the insertion of an interbody cage. The surgery is performed under constant irrigation with normal saline and an optical endoscopic lens close to the targeted disc segment. Two main subtypes of uniportal endoscopic fusion are currently described in the literature. We broadly classify them into facet-preserving and facet-sacrificing endoscopic lumbar interbody fusions. We have termed them uniportal facet-preserving trans-Kambin endoscopic fusion and uniportal facet-sacrificing posterolateral transforaminal lumbar interbody fusion. In this article, we review the current literature and discuss the history, indications, contraindications, technical differences, clinical outcomes, and complications of uniportal endoscopic interbody fusion surgery.

How I do it? Uniportal full endoscopic pseudoarthrosis release of left L5/S1 Bertolotti's syndrome under intraoperative computer tomographic guidance in an ambulatory setting

BACKGROUND

There is limited literature on technique full endoscopic pseudoarthrosis release of Bertolotti syndrome.

METHODS

Uniportal full endoscopic pseudoarthrosis release technique applies for patients presenting with symptomatic Bertolotti's syndrome. Full-thickness endoscopic drilling is carried out from most ventrolateral margin of pseudoarthrosis articulating with the highest part of sacral ala (PH) point to dorsal medioinferior margin of pseudoarthrosis adjacent to superior articular process (MS) point. Complete pseudoarthrosis release was confirmed with an intraoperative 3D imaging system.

CONCLUSION

The uniportal full endoscopic pseudoarthrosis release is a good alternative to open surgery to release pseudoarthrosis in L5/S1 Bertolotti's syndrome in an ambulatory setting.

Evaluation of Two Methods (Inside-Out/Outside-In) Inferior Articular Process Resection for Uniportal Full Endoscopic Posterolateral Transforaminal Lumbar Interbody Fusion: Technical Note

Objective: There is limited literature comparing the uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion outside-in approach (ETLIF (O)) with the inside-out approach (ETLIF (I)). Methods: Radiological evaluation was performed on disc height restoration and coronal wedging angle, and operation time (inferior articular process resection time/total operation time) and clinical evaluation were made. Result: 48 cases of inside-out and 38 cases of outside-in cases were included. Compared to inside-out, the outside-in approach had significantly less operative time required to resect inferior articular process: 36.55 ± 10.37, and total operative time: 87.45 ± 20.14 min compared to 49.83 ± 23.97 and 102.56 ± 36.53 min, respectively, for the inside-out approach, p < 0.05. Compared to the preoperative state, both cohorts achieved significant improvement of VAS and ODI at post-operative 1 week, 3 months and at final follow up. Both cohorts achieved statistically significant increased disc height with 5.00 ± 2.87 mm, 5.49 ± 2.33 mm and statistically significant improvement in coronal wedge angle with 1.76 ± 1.63°, 3.24 ± 2.92° in the inside-out and outside-in approaches respectively. Conclusions: Complete removal of inferior articular process is the key part of endoscopic fusion with two methods that can be applied: an inside-out approach or an outside-in approach. Comparing both techniques, the outside-in approach has a shorter operative time required for inferior articular process resection and total length of operation with similar good clinical and radiological outcomes.

Research Tendency in Lumbar Spinal Stenosis over the Past Decade: A Bibliometric Analysis

OBJECTIVE

The purpose of this bibliometric analysis was to identify trends and hot topics in research on lumbar spinal stenosis (LSS) over the past decade, for helping researchers explore new directions for future research in that area.

METHODS

All research articles on LSS, written in English and indexed in the Web of Science database (WoS) between 2010 and 2020, were used. The visualization of network and in-depth bibliometric analysis including the number of publications, countries, institutions, journals, authors, cited references, and key words was carried out with the help of CiteSpace.

RESULTS

A total of 4033 papers (3577 original articles and 476 reviews) were identified and included in the study. The most productive year was in 2019. The Spine was the journal that published the highest number of articles and received the most citations. The most productive country and institutions in this field were the United States and Seoul National University, respectively. Kim HJ was the most prolific author, and Deyo RA ranked the first in the cited authors. The most cited article was published in 2010 by Deyo et al. and described the complications and charges index for LSS. From the coword cluster analysis, there were 3 frontiers in lumbar spinal stenosis: intervention, outcomes, and pathogenesis.

CONCLUSIONS

We have summarized the literature on LSS in the past decade including publication information, country, institution, authors, and journal. Research on minimally invasive surgery, outcomes, and gene therapies in LSS will be hot topics in the future.

Clinical Results and Complications of Endoscopic Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Meta-Analysis

BACKGROUND

Although endoscopic transforaminal lumbar interbody fusion (TLIF) may combine the advantages of minimally invasive fusion and endoscopic spine surgery, little evidence exists on endoscopic TLIF. This meta-analysis investigated the clinical results of endoscopic TLIF.

METHODS

We performed a systematic search of Web-based electronic databases to identify articles on endoscopic lumbar interbody fusion. Only studies of water-based endoscopic TLIF with pedicle screw fixation were included. We analyzed preoperative and postoperative scores for the Oswestry Disability Index (ODI) and visual analog scales (VASs) for back and leg pain to evaluate clinical efficacy. The minimal clinically important difference (MCID) of VAS and ODI was analyzed. We calculated differences in means and 95% confidence intervals and investigated indications for endoscopic TLIF, surgical approaches for endoscopic TLIF, the endoscopic systems that were used, and procedure-related complications.

RESULTS

Thirteen articles were included in this meta-analysis. Uniportal and biportal endoscopic systems were used. Six articles used the posterolateral approach and 7 used the trans-Kambin approach. Preoperative ODI and VAS scores for leg and back pain significantly improved after endoscopic TLIF with percutaneous pedicle screw fixation (P = 0.00). The ODI significantly improved by twice as much as the MCID. The mean change in the VAS for back and leg pain showed significant improvements over the MCID. The perioperative complications were usually minor.

CONCLUSIONS

The early clinical results of endoscopic TLIF with percutaneous pedicle screw fixation are favorable. However, long-term outcomes should be investigated and randomized controlled trials should be conducted.