How I do it? Uniportal full endoscopic contralateral approach for lumbar foraminal stenosis with double crush syndrome

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.

Revisional Endoscopic Foraminal Decompression via Modified Interlaminar Approach at L5-S1 after Failed Posterior Instrumented Lumbar Fusion in Elderly Patients

Elderly people usually have poorer surgical tolerance and a higher incidence of complications when undergoing revision surgery after posterior instrumented lumbar fusion (PILF). Full-endoscopic transforaminal surgery is a safe and effective option, but sometimes, it is difficult to revise L5-S1 foraminal stenosis (FS) after PILF. Therefore, we developed full-endoscopic lumbar decompression (FELD) at the arthrodesis level via a modified interlaminar approach under local anesthesia. This study aimed to describe the technical note and clinical efficacy of the technique. Eleven patients with unilateral lower limb radiculopathy after PILF underwent selective nerve root block and then underwent FELD. Magnetic resonance imaging (MRI) and computer tomography (CT) were performed on the second postoperative day. Their clinical outcomes were evaluated with a Visual analog scale (VAS) of low back pain and sciatica pain, Oswestry disability index (ODI), and the MacNab score. Complete decompression was achieved in every case with FELD without serious complications. Postoperative VAS of sciatica pain and ODI at each time point and VAS of low back pain and ODI after three months postoperatively were significantly improved compared with those preoperative (p < 0.05). According to the MacNab criteria, seven patients (63.6%) had excellent results at the two-year follow-up, and four patients (36.4%) had good results. No patients required further revision surgery. FELD, via a modified interlaminar approach, is effective for treating unilateral L5-S1 FS after PILF in elderly people.

"Knowing It Before Blocking It," the ABCD of the Peripheral Nerves: Part B (Nerve Injury Types, Mechanisms, and Pathogenesis)

Selander emphatically said, "Handle these nerves with care," and those words still echo, conveying a loud and clear message that, however rare, peripheral nerve injury (PNI) remains a perturbing possibility that cannot be ignored. The unprecedented nerve injuries associated with peripheral nerve blocks (PNBs) can be most tormenting for the unfortunate patient and a nightmare for the anesthetist. Possible justifications for the seemingly infrequent occurrences of PNB-related PNIs include a lack of documentation/reporting, improper aftercare, or associated legal implications. Although they make up only a small portion of medicolegal claims, they are sometimes difficult to defend. The most common allegations are attributed to insufficient informed consent; preventable damage to a nerve(s); delay in diagnosis, referral, or treatment; misdiagnosis, and inappropriate treatment and follow-up care. Also, sufficient prospective studies or randomized trials have not been conducted, as exploring such nerve injuries (PNB-related) in living patients or volunteers may be impractical or unethical. Understanding the pathophysiology of various types of nerve injury is vital to dealing with them further. Processes like degeneration, regeneration, remyelination, and reinnervation can influence the findings of electrophysiological studies. Events occurring in such a process and their impact during the assessment determine the prognosis and the need for further interventions. This educational review describes various types of PNB-related nerve injuries and their associated pathophysiology.

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.

New strategies for the treatment of intervertebral disc degeneration: cell, exosome, gene, and tissue engineering

Low back pain (LBP) caused by intervertebral disc (IVD) generation (IVDD) has always been an important problem that cannot be ignored. Traditional therapies have many deep-rooted and intractable complications that promote their treatment mode transfer to new therapies. This article mainly summarizes the shortcomings of traditional treatment methods and analyzes the research status and future development direction of IVDD treatment. We outlined the most promising IVDD therapies, including cell, exosome, gene, and tissue engineering therapy, especially tissue engineering therapy, which runs through the whole process of other therapies. In addition, the article focuses on the cellular, animal, and preclinical challenges faced by each therapeutic approach, as well as their respective advantages and disadvantages, to provide better ideas for relieving the IVDD patients' pain through new treatment methods.

Role of electromyography and ultrasonography in the diagnosis of double crush lumbar radiculopathy and common fibular injury: illustrative cases

BACKGROUND

Double crush syndrome consists of two compression sites along a peripheral nerve and is rare in the lower extremities. Electrodiagnostic and ultrasound (US) studies may be helpful in evaluating foot drop involving overlapping pathologies.

OBSERVATIONS

Case 1 involved a man who presented with left dorsiflexor weakness and left foot numbness. Electromyography (EMG) revealed a left common fibular nerve entrapment neuropathy and left L5 radiculopathy. US and magnetic resonance imaging (MRI) revealed a large cystic lesion of the left common fibular nerve treated by cyst removal. The left foot drop persisted postoperatively. Lumbar computed tomography myelography revealed severe left foraminal stenosis at L5–S1. Multilevel lumbar laminectomies and facetectomies with an L5–S1 fusion were performed. Within 1 month postoperatively, the left foot drop had improved. Case 2 involved a man who developed a right foot drop caused by right lumbar foraminal stenosis at L4–5 and L5–S1. EMG and US of the right common fibular neuropathy showed large fascicles involving the right common fibular nerve. MRI revealed a hyperintense signal of the right common fibular nerve. Spontaneous improvement occurred within 6 months without surgery.

LESSONS

Spine surgeons should recognize double crush in the lower extremities. EMG and US are valuable in detecting peripheral nerve abnormalities, especially in cases with overlapping lumbar pathology.

Comparative Clinical and Radiographic Cohort Study: Uniportal Thoracic Endoscopic Laminotomy With Bilateral Decompression by Using the 1-Block Resection Technique and Thoracic Open Laminotomy With Bilateral Decompression for Thoracic Ossified Ligamentum Flavum

BACKGROUND

Symptomatic thoracic myelopathy secondary to thoracic ossified ligamentum flavum (OLF) often requires decompression spinal surgery.

OBJECTIVE

To compare clinical and radiological outcomes in uniportal endoscopic vs open thoracic decompression for thoracic OLF.

METHODS

Retrospective evaluation of patients who underwent uniportal thoracic endoscopic unilateral laminotomy with bilateral decompression (TE-ULBD) by using the one-block resection technique compared with thoracic open laminotomy (TOL) with bilateral decompression. Radiological outcomes in MRI scan and clinical charts were evaluated.

RESULTS

Thirty-five levels of TE-ULBD were compared with 24 levels of TOL. The overall complication rate of TOL was 15% while TE-ULBD was 6.5%. Both TOL and TE-ULBD cohort had significantly improved their visual analog scale (VAS), Oswestry Disability Index, and Japanese Orthopaedic Association (JOA) myelopathy score after operation. Comparative analysis of TE-ULBD performed statistically and significantly better than TOL in improvement of final VAS and JOA scores. The mean difference ± standard deviation of VAS and JOA improvement in final follow-up when compared with preoperative state of TE-ULBD and TOL was 0.717 ± 0.131 and 1.03 ± 0.2, respectively, P < .05. The mean Hirabayashi recovery rates were 94.5% (TE-ULBD) and 56.8% (TOL). There was no statistical difference in change in preoperative and final Oswestry Disability Index and MRI volume at upper endplate, middisk, and lower endplate canal cross-sectional area.

CONCLUSION

Uniportal TE-ULBD achieved significantly improved pain and neurological recovery with sufficient spinal canal decompression, as compared with thoracic open laminectomy for patients with myelopathy secondary to OLF in our cohort.

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.

The Comparison of Fluoroscopy-Guided Epidural Anesthesia with Conscious Sedation and General Anesthesia for Endoscopic Lumbar Decompression Surgery: A Retrospective Analysis

BACKGROUND

With advances and refinements in endoscopic lumbar spine surgery showing effective and satisfactory results, the need for simple yet effective anesthetic techniques for minimally invasive endoscopic spine surgery has increased. The aim of this study was to compare feasibility and postoperative outcomes of fluoroscopy-guided epidural anesthesia with general anesthesia in patients undergoing endoscopic lumbar decompression surgery (≤3 levels).

METHODS

Patients who underwent 1-3 levels of endoscopic lumbar decompression surgery under either fluoroscopy-guided epidural or general anesthesia between January 2019 and October 2020 were retrospectively reviewed. Postoperative pain intensity and use of rescue analgesics for up to 48 hours were compared between the epidural and general anesthesia groups. Intraoperative anesthetic data and postoperative recovery profiles were also analyzed.

RESULTS

Postoperative pain scores were significantly lower in the epidural anesthesia group compared with the general anesthesia group at 10 minutes after recovery room admission (2.1 ± 1.8 vs. 5.7 ± 1.9, P < 0.001), 24 hours postoperatively (3.3 ± 1.0 vs. 5.4 ± 1.8, P < 0.001), and 48 hours postoperatively (3.2 ± 0.6 vs. 4.4 ± 1.4, P < 0.001). The proportion of patients requiring rescue analgesics in the recovery room was significantly lower in the epidural anesthesia group (1.9% vs. 20.5%, P = 0.027). The median 15-item Quality of Recovery score on postoperative day 1 was significantly higher in the epidural anesthesia group (118.0 [113.5-123.0] vs. 82.0 [73.5-111.5], P < 0.001). Occurrence of nausea, vomiting, and voiding difficulty up to 48 hours postoperatively did not differ between groups.

CONCLUSIONS

Compared with general anesthesia, epidural anesthesia provided better analgesia and recovery characteristics during the early postoperative period in endoscopic lumbar decompression surgery.

Contralateral sublaminar approach for decompression of the combined lateral recess, foraminal, and extraforaminal lesions using biportal endoscopy: a technical report

BACKGROUND

The development of specialized instruments and surgical techniques has enabled the biportal endoscopic system to access the foraminal and extraforaminal area using the contralateral sublaminar approach at the lumbar level.

METHODS

Biportal endoscopic contralateral sublaminar approach was used to resolve the contralateral foraminal, and extraforaminal stenosis at the lumbar level. Prominent syndesmophytes and herniated disc compression of the exiting nerve root were successfully removed, and the distorted nerve root was restored to a smooth downward angulation in the far-out area.

CONCLUSION

We successfully utilized biportal endoscopy to decompress the combined lumbar lateral recess, foraminal, and extraforaminal lesions using a contralateral sublaminar approach.

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.

The Novel Technique of Uniportal Endoscopic Interlaminar Contralateral Approach for Coexisting L5-S1 Lateral Recess, Foraminal, and Extraforaminal Stenosis and Its Clinical Outcomes

BACKGROUND

Multifocal intra-and-extraspinal lumbar stenotic lesions could be decompressed with one endoscopic surgical approach, which has the advantages of functional structure preservation, technical efficacy, and safety.

METHODS

A retrospective study was performed on 48 patients who underwent uniportal endoscopic contralateral approach due to coexisting lateral recess, foraminal, and extraforaminal stenosis at the L5-S1 level. Foraminal stenosis grade and postoperative dysesthesia (POD) were analyzed. Visual analog scale (VAS) pain scores, modified Oswestry Disability Index (ODI) scores, and MacNab criteria for evaluating pain disability and response were analyzed.

RESULTS

The foraminal stenosis grade of the treated spinal levels was grade 1 (n = 16, 33%), grade 2 (n = 20, 42%), and grade 3 (n = 12, 25%). The rate of occurrence of POD grade 2 and above, which may be related to intraoperative dorsal root ganglion (DRG) retraction injury, was revealed to be 4.2% (two with grade 2, none with grade 3). The patients showed favorable clinical outcomes.

CONCLUSIONS

Uniportal endoscopic interlaminar contralateral approach is an effective procedure to resolve combined stenosis (lateral recess, foraminal, and extraforaminal region) with one surgical approach at the L5-S1 level. It may be a minimal DRG retracting and facet joint preserving procedure in foraminal and extraforaminal decompression.

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.

Effect of Dorsal Root Ganglion Retraction in Endoscopic Lumbar Decompressive Surgery for Foraminal Pathology: A Retrospective Cohort Study of Interlaminar Contralateral Endoscopic Lumbar Foraminotomy and Discectomy versus Transforaminal Endoscopic Lumbar Foraminotomy and Discectomy

OBJECTIVE

Postoperative dysesthesia (POD) is a common complication in surgery involving foraminal diseases, including lumbar foraminal or extraforaminal herniated nucleus pulposus (HNP). Minimal dorsal root ganglion (DRG) retraction is key to preventing POD. We compared the clinical results, safety, and efficacy between the paraspinal transforaminal approach requiring DRG retraction and the interlaminar contralateral approach without DRG retraction for foraminal and extraforaminal diseases.

METHODS

A retrospective cohort study was performed of 50 patients who underwent uniportal transforaminal endoscopic lumbar foraminotomy and discectomy (TELD) and 50 patients who underwent anuniportal interlaminar contralateral endoscopic lumbar foraminotomy and discectomy (ICELF) because of lumbar foraminal HNP. The operated levels, combined degenerative diseases, postoperative complications, and POD were analyzed. The visual analog scale (VAS) pain scores, modified Oswestry Disability Index, and MacNab criteria for evaluating pain disability and response were analyzed.

RESULTS

In the ICELF group (total, n = 7, 14%), there were 5 (10%) and 2 (4%) patients with POD grade 1 and 2, respectively. In the TELD group (total, n = 13, 26%), there were 7 (14%), 5 (10%), and 1 (2%) patients with POD grade 1, 2, and 3, respectively. The overall occurrence rate of grade 2 and greater POD was higher in the TELD group (n = 6, 12%) than in the ICELF group (n = 2, 4%). In the ICELF group, 3 of 9 patients (33%) with combined canal structure deforming diseases had POD, of whom none had POD of grade 2 and greater. In the TELD group, 4 of 7 patients (57%) with combined canal structure deforming diseases had POD, of whom all had POD of grade 2 and greater. Two surgical groups showed favorable clinical outcomes with the visual analog scale, Oswestry Disability Index, and MacNab criteria.

CONCLUSIONS

Both TELD and ICELF were found to treat foraminal or extraforaminal HNP with good clinical outcomes. ICELF might have a lower POD rate in complicated cases such as adjacent segment disease, degenerative spondylolisthesis, and isthmic spondylolisthesis. This surgical procedure could be an alternative in complicated cases or in patients with an anatomically limited L5-S1 level. However, the procedure is technically challenging to perform.

Early Career Challenges in Setting Up an Endoscopic Spine Surgery Practice

After the completion of an endoscopic spinal surgery fellowship, the next challenge for the newly minted consultant is to set up a viable and sustainable endoscopic practice. A successful practice of endoscopic spine surgery is dependent on several factors, such as anesthetic support; surgical expertise; support for provision and maintenance of endoscopic equipment; cost of equipment; administrative and nursing support; postoperative care services to optimize patients' outcome and satisfaction; patients' ideas, concerns, and expectations, as well as continuing medical education. In this article, a perspective is given on the early career challenges that a fellowship-trained endoscopic surgeon may encounter in the period leading to first successful endoscopic spinal surgery.

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

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

Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression Outside-In Approach: A Proctorship Guideline With 12 Steps of Effectiveness and Safety

Minimally invasive spinal surgery in particular lumbar endoscopic unilateral laminotomy with bilateral decompression becomes popular as it can be performed with regional anesthesia, soft tissue damages are minimized as endoscopic visualization and instruments can be brought close to operating area bypassing much of the intervening soft tissues for sufficient spinal decompression with ligamentum flavum resection despite less bony resection compared to open surgery. Overall, when well executed, it preserves spinal stability. Outside-in technique of decompression is also known as over the top decompression in minimally invasive literature. It involves maintaining deep layer of ligamentum flavum integrity till satisfactory bony decompression is achieved. Deep layer of ligamentum flavum is removed as final step of decompression. Preservation of the deep layer of ligamentum flavum protects the neural elements, allowing drills and sharp equipment to be used safely to perform bony decompression.In this study, we demonstrate the technical details of outside-in approach lumbar endoscopic unilateral laminotomy with bilateral decompression (LE-ULBD). LE-ULBD Outside-in Technique is an effective and safe procedure in relieving lumbar spinal stenosis with favorable results with a follow-up for more than 1 year.

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

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

Uniportal Full Endoscopic Posterolateral Transforaminal Lumbar Interbody Fusion with Endoscopic Disc Drilling Preparation Technique for Symptomatic Foraminal Stenosis Secondary to Severe Collapsed Disc Space: A Clinical and Computer Tomographic Study with Technical Note

Background: Severe collapsed disc secondary to degenerative spinal conditions leads to significant foraminal stenosis. We hypothesized that uniportal posterolateral transforaminal lumbar interbody fusion with endoscopic disc drilling technique could be safely applied to the collapsed disc space to improve patients’ pain score, restore disc height, and correct the segmental angular parameters. Methods: We included patients who met the indication criteria for lumbar fusion and underwent uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion with pre-operative Computer Tomography mid disc height of less than or equal to 5 mm and MRI of Grade 3 Foraminal Stenosis. Visual analogue scale and computer tomography pre-operative and post-operative sagittal disc height in the anterior, middle and posterior part of the disc; sagittal focal segmental angle; mid coronal disc height and coronal wedge angles were evaluated. Results: 30 levels of Endo-TLIF were included, with a mean follow up of 12 months. The mean improvement in decreasing pain score was 2.5 ± 1.1, 3.2 ± 0.9 and 4.3 ± 1.0 at 1 week post operation, 3 months post operation and at final follow up, respectively, p < 0.05. There was significant increase in mid sagittal computer tomographic anterior, middle and posterior disc height of 6.99 ± 2.30, 6.28 ± 1.44, 5.12 ± 1.79 mm respectively, p < 0.05. CT mid coronal disc height showed an increase of 7.13 ± 1.90 mm, p < 0.05. There was a significant improvement in the CT coronal wedge angle of 2.35 ± 4.73 and the CT segmental focal sagittal angle of 1.98 ± 4.69, p < 0.05. Conclusion: Application of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion in patients with severe foraminal stenosis secondary to severe collapsed disc space significantly relieved patients’ pain and restored disc height without early subsidence or exiting nerve root dysesthesia in our cohort of patients.

Technical Considerations of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion: A Review of Its Early Clinical Results in Application in Adult Degenerative Scoliosis

BACKGROUND

Uniportal endoscopic posterolateral lumbar interbody fusion (Endo-TLIF) provides one of the least invasive forms of minimally invasive surgery, allowing large size cages which are commercially available for open and tubular microscopic transforaminal lumbar interbody fusion (TLIF) to be inserted through this approach. We studied the effect of such a technique on a series of patients with low-grade degenerative scoliosis.

METHODS

Endo-TLIF was applied to patients who had 10°-40° of degenerative adult scoliosis. Pre- and postoperative 1-week, 3-month, and final follow-up clinical status of visual analog scale, Oswestry Disability Index, perioperative complications, and Macnab criteria were collected. Roentgenogram to assess changes in Cobb angles was done.

RESULTS

There was statistically significant improvement of preoperative, 1-week postoperative, 3-month postoperative, and final follow-up mean of visual analog scale scores with 7.72 (5-10), 3.68 (3-6), 2.88 (2-4), and 1.96 (1-3), respectively, and with Oswestry Disability Index mean of 70.4 (52-86), 35.12 (26-56), 27.68 (24-38), and 24 (20-28), respectively (P < 0.05). In terms of Macnab criteria, 100% had good to excellent result. In terms of scoliosis measured by Cobb angle, there was statistically significant improvement.

CONCLUSIONS

Endo-TLIF is a safe and effective procedure in mild to moderate degenerative scoliosis with good early clinical results and improvement in coronal Cobb angle. It can be considered as an option if a short segment(s) fusion is planned for adult degenerative scoliosis.

Intervertebral Disc Diseases PART 2: A Review of the Current Diagnostic and Treatment Strategies for Intervertebral Disc Disease

With an aging population, there is a proportional increase in the prevalence of intervertebral disc diseases. Intervertebral disc diseases are the leading cause of lower back pain and disability. With a high prevalence of asymptomatic intervertebral disc diseases, there is a need for accurate diagnosis, which is key to management. A thorough understanding of the pathophysiology and clinical manifestation aids in understanding the natural history of these conditions. Recent developments in radiological and biomarker investigations have potential to provide noninvasive alternatives to the gold standard, invasive discogram. There is a large volume of literature on the management of intervertebral disc diseases, which we categorized into five headings: (a) Relief of pain by conservative management, (b) restorative treatment by molecular therapy, (c) reconstructive treatment by percutaneous intervertebral disc techniques, (d) relieving compression and replacement surgery, and (e) rigid fusion surgery. This review article aims to provide an overview on various current diagnostic and treatment options and discuss the interplay between each arms of these scientific and treatment advancements, hence providing an outlook of their potential future developments and collaborations in the management of intervertebral disc diseases.

Lumbar Degenerative Disease Part 1: Anatomy and Pathophysiology of Intervertebral Discogenic Pain and Radiofrequency Ablation of Basivertebral and Sinuvertebral Nerve Treatment for Chronic Discogenic Back Pain: A Prospective Case Series and Review of Literature

Degenerative disc disease is a leading cause of chronic back pain in the aging population in the world. Sinuvertebral nerve and basivertebral nerve are postulated to be associated with the pain pathway as a result of neurotization. Our goal is to perform a prospective study using radiofrequency ablation on sinuvertebral nerve and basivertebral nerve; evaluating its short and long term effect on pain score, disability score and patients’ outcome. A review in literature is done on the pathoanatomy, pathophysiology and pain generation pathway in degenerative disc disease and chronic back pain. 30 patients with 38 levels of intervertebral disc presented with discogenic back pain with bulging degenerative intervertebral disc or spinal stenosis underwent Uniportal Full Endoscopic Radiofrequency Ablation application through either Transforaminal or Interlaminar Endoscopic Approaches. Their preoperative characteristics are recorded and prospective data was collected for Visualized Analogue Scale, Oswestry Disability Index and MacNab Criteria for pain were evaluated. There was statistically significant Visual Analogue Scale improvement from preoperative state at post-operative 1wk, 6 months and final follow up were 4.4 ± 1.0, 5.5 ± 1.2 and 5.7 ± 1.3, respectively, p < 0.0001. Oswestery Disability Index improvement from preoperative state at 1week, 6 months and final follow up were 45.8 ± 8.7, 50.4 ± 8.2 and 52.7 ± 10.3, p < 0.0001. MacNab criteria showed excellent outcomes in 17 cases, good outcomes in 11 cases and fair outcomes in 2 cases Sinuvertebral Nerve and Basivertebral Nerve Radiofrequency Ablation is effective in improving the patients’ pain, disability status and patient outcome in our study.