Unilateral biportal endoscopic transforaminal lumbar interbody fusion versus conventional interbody fusion for the treatment of degenerative lumbar spine disease: a systematic review and meta-analysis

A Novel Unilateral Bi/Multi-Portal Endoscopic Transforaminal Interbody Fusion Utilizing Uniaxial Spinal Endoscope Instead of Arthroscope: Technical Note and Preliminary Clinical Results

BACKGROUND

Currently, traditional UBE surgery, which is based on arthroscope, has been increasingly employed for complex lumbar degenerative diseases. However, this approach is associated with complications such as intraoperative dural sac tears, nerve root injuries, and postoperative epidural hematomas. In response to these challenges, we propose a novel technique utilizing uniaxial spinal endoscope to replace arthroscope-Unilateral Bi/Multi-Portal Endoscopy (UME). This new method has successfully treated complex lumbar disc herniation and spinal stenosis, resulting in improved postoperative outcomes and a reduction in complications. Based on the previous findings, we utilized uniaxial spinal endoscopy as the primary operating method, with the assistance of multi-portal endoscopic techniques (UME-TLIF), to perform transforaminal lumbar interbody fusion. The feasibility and preliminary clinical results have been presented in this paper.

METHODS

A total of 18 patients (8 men and 10 women, aged 52.6 ± 15.29 years) diagnosed with lumbar degenerative diseases, such as giant lumbar disc herniation, severe lumbar spinal stenosis, or lumbar spondylolisthesis, were included in this study from January 2022 to March 2023. Various parameters including operation time, ambulatory time, intraoperative fluoroscopy times, hospitalization days, and complications were recorded during the perioperative period. Clinically relevant symptoms were evaluated and documented 1, 3, 6, and 12 months postoperatively. Visual analogue scale (VAS) scores for lower back pain and leg pain, as well as the Oswestry disability index (ODI), were measured. The extent of lumbar interbody fusion was assessed using lumbar X-ray and CT scans at the 12-months follow-up. MRI was performed to assess the degree of nerve decompression in patients at the same time points. The paired t-test or Wilcoxon signed-rank test were used as statistical methods.

RESULTS

The single-segment UME-TLIF procedure had an average operation time of 211 ± 53.3 min, and the average number of X-rays taken during the operation was 11.78 ± 5.32. Patients were able to walk and perform functional exercises approximately 35.11 ± 8.41 h post-surgery, and the average duration of hospital stay was 8.5 ± 2.27 days. The VAS and ODI values at each time point post-surgery were significantly lower than the respective pre-surgery values (p < 0.05). Two patients developed postoperative sensory disturbances which significantly improved with conservative treatment. Furthermore, a follow-up CT scan conducted 12 months post-surgery showed 100% fusion rate of the surgical segments in all patients.

CONCLUSION

UME-TLIF is an endoscopy-assisted fusion procedure that minimizes muscle damage in patients and allows early rehabilitation. This technique broadens the surgical applications of uniaxial spinal endoscope as a surgical tool, particularly benefitingpatients diagnosed with severe lumbar disc herniation and lumbar instability.

Clinical Efficacy of Unilateral Biportal Endoscopic Transforaminal Lumbar Interbody Fusion

Unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) is an advanced, minimally invasive spinal surgical technique characterized by the use of 2 discrete portals-one for clear visualization and continuous irrigation and the other for the dexterous manipulation of surgical instruments. This configuration not only affords an expanded view (0° or 30°) but also enhances the freedom of movement for instruments, thereby augmenting the precision and flexibility of the surgery. The superiority of UBE-TLIF lies in its capacity to facilitate rapid postoperative recovery with minimal trauma, reduced intraoperative bleeding, abbreviated hospital stays, and significant amelioration of postoperative lower back pain. Comparatively, UBE-TLIF demonstrates equivalent fusion rates and clinical outcomes to traditional open surgeries while also increasing patient satisfaction.1-3 In the UBE-TLIF procedure, the potential for nerve root disturbance due to surgical manipulation is a critical consideration. To minimize this, the authors have refined the surgical approach, as demonstrated in Video 1. The insertion of a guidewire is prioritized before the fusion process for 2 key reasons: to ensure accurate segmental alignment under the biportal endoscope and to avoid the risk of spinal canal injury that could arise if the guidewire were to be inserted after spinal decompression. The horizontal orientation of the cage is a pivotal technique, as it not only restores spinal curvature effectively but also circumvents the complications associated with oblique insertion, including the prevention of contralateral foraminal narrowing. This strategic positioning is vital for optimizing spinal alignment and reducing the likelihood of iatrogenic issues.4 After cage implantation, the decompression of the dorsal ligamentum flavum is carefully executed, with an emphasis on preserving the ligament to lessen the potential irritation to the nerve roots during the implantation process. This nuanced approach ensures that while achieving spinal fusion, there is also a significant reduction in the risk of nerve root stimulation, striking a harmonious balance between the goals of spinal stabilization and neural element safety. In this video demonstration, we highlight 2 key advantages of the UBE-TLIF procedure4,5: (1) Optimal lordosis and stability via cage technique: This study introduces a cage-rotation technique that enhances the accuracy and efficacy of UBE-TLIF. The fusion cage is meticulously inserted at a 45° angle to the lamina, with the process halted once two thirds of the cage is in place. An assistant then delicately taps the final one-third segment, ensuring the cage is perfectly aligned with the posterior vertebral edge. This method differs from the traditional oblique insertion, as it significantly improves the spinal lordosis by augmenting disc height, segmental lordosis, and overall lumbar curvature. Additionally, the traverse cage positioning provides enhanced stability, marked by a greater posterior distance from the vertebral body, thus minimizing the potential for cage subsidence or migration. (2) Prioritizing fusion cage insertion for refined decompression6: By prioritizing the fusion cage insertion before the neural decompression, our approach underscores the importance of preserving the ligamentum flavum. This technique reduces neural irritation during the procedure, leading to an improved patient experience postoperatively. UBE-TLIF offers a safe, efficacious, and swiftly recuperative minimally invasive option for the treatment of lumbar degenerative diseases. It diminishes reliance on costly equipment, thereby facilitating the dissemination and application of this technology in community hospitals.7.

Comparison of efficacy and safety between unilateral biportal endoscopic transforaminal lumbar interbody fusion versus uniportal endoscopic transforaminal lumbar interbody fusion for the treatment of lumbar degenerative diseases: a systematic review and meta-analysis

BACKGROUND

This meta-analysis was performed to comprehensively evaluate the efficacy and safety of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) versus uniportal endoscopic transforaminal lumbar interbody fusion (Endo-TLIF) for the treatment of lumbar degenerative diseases.

METHODS

We electronically searched PubMed, Embase, Scopus, Web of Science, the Cochrane Library, the Wanfang Database, and China National Knowledge Infrastructure to identify controlled clinical studies on the efficacy and safety of UBE-TLIF and Endo-TLIF for lumbar degenerative diseases from database establishment to December 2023. Two researchers screened the literature, extracted data, and evaluated the risk of bias of the included studies. They also recorded the authors, sample size, operative time, intraoperative blood loss, hospital length of stay, complication rate, fusion rate, visual analogue scale scores, and Oswestry disability index in each study. The meta-analysis was performed using RevMan 5.4 software provided by the Cochrane Library.

RESULTS

Five studies involving 314 patients met the inclusion criteria for this meta-analysis. The UBE-TLIF group comprised 154 patients, and the Endo-TLIF group comprised 160 patients. UBE-TLIF was superior to Endo-TLIF in terms of the operative time and fusion rate. There were no significant differences in the intraoperative blood loss, hospital length of stay, complication rate, visual analogue scale scores, or Oswestry disability index between the two groups.

CONCLUSION

Both UBE-TLIF and Endo-TLIF can achieve satisfactory clinical results with respect to improving low back and leg pain in patients with lumbar degenerative diseases. However, UBE-TLIF has the advantages of a shorter operative time and higher fusion rate.

TRIAL REGISTRATION

This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (ID: CRD42023495076).

Comparative efficacy and fusion outcomes of unilateral bi-portal endoscopic transforaminal lumbar interbody fusion versus minimally invasive transforaminal lumbar interbody fusion in treating single-segment degenerative lumbar spondylolisthesis with lumbar spinal stenosis: a two-year retrospective study

BACKGROUND

Degenerative lumbar spondylolisthesis (DLS) with lumbar spinal stenosis (LSS) is a common condition resulting in substantial lower back pain and disability. Surgical intervention is recommended only when conservative treatment fails. This study compared UBE-TLIF and MIS-TLIF regarding clinical outcomes and fusion rates in patients with single-segment DLS with LSS.

METHODS

A total of 85 patients who underwent either UBE-TLIF (n = 40) or MIS-TLIF (n = 45) were examined retrospectively. Clinical results were evaluated by the Visual Analog Scale (VAS) for pain and the Oswestry Disability Index (ODI) for functional outcomes. Radiographs and CT were utilized to assess radiological outcomes such as disc height (DH), lumbar lordosis (LL), and interbody fusion rates. The two groups were also compared in terms of perioperative data (operation time, blood loss, hospital stay, and fluoroscopy exposure).

RESULTS

Both surgical techniques showed similar statistically significant improvements in VAS and ODI scores. Fusion rates at 2 years postoperatively were identical, including 95% for the UBE-TLIF group and 97.7% for the MIS-TLIF group. However, compared with MIS-TLIF, the operative time and fluoroscopy exposure were longer for UBE-TLIF, but intraoperative blood loss and length of hospital stay were reduced.

CONCLUSIONS

UBE-TLIF and MIS-TLIF can successfully treat single-segment DLS in the presence of LSS, achieving similar clinical and radiological outcomes with low complication rates. Although UBE-TLIF has certain advantages regarding perioperative outcomes (less blood loss and shorter hospital stay), MIS-TLIF is associated with shorter operative times and lower fluoroscopy exposure.

Effect of Cage Material and Size on Fusion Rate and Subsidence Following Biportal Endoscopic Transforaminal Lumbar Interbody Fusion

OBJECTIVE

Biportal endoscopic transforaminal lumbar interbody fusion (BE-TLIF) is an emerging, minimally invasive technique performed under biportal endoscopic guidance. However, concerns regarding cage subsidence and sufficient fusion during BE-TLIF necessitate careful selection of an appropriate interbody cage to improve surgical outcomes. This study compared the fusion rate, subsidence, and other radiographic parameters according to the material and size of the cages used in BE-TLIF.

METHODS

In this retrospective cohort study, patients who underwent single-segment BE-TLIF between April 2019 and February 2023 were divided into 3 groups: group A, regular-sized three-dimensionally (3D)-printed titanium cages; group B, regular-sized polyetheretherketone cages; and group C, large-sized 3D-printed titanium cages. Radiographic parameters, including lumbar lordosis, segmental lordosis, anterior and posterior disc heights, disc angle, and foraminal height, were measured before and after surgery. The fusion rate and severity of cage subsidence were compared between the groups.

RESULTS

No significant differences were noted in the demographic data or radiographic parameters between the groups. The fusion rate on 1-year postoperative computed tomography was comparable between the groups. The cage subsidence rate was significantly lower in group C than in group A (41.9% vs. 16.7%, p=0.044). The severity of cage subsidence was significantly lower in group C (0.93±0.83) than in groups A (2.20±1.84, p=0.004) and B (1.79±1.47, p=0.048).

CONCLUSION

Cage materials did not affect the 1-year postoperative outcomes of BE-TLIF; however, subsidence was markedly reduced in large cages. Larger cages may provide more stable postoperative segments.

Innovative Developments in Lumbar Interbody Cage Materials and Design: A Comprehensive Narrative Review

This review comprehensively examines the evolution and current state of interbody cage technology for lumbar interbody fusion (LIF). This review highlights the biomechanical and clinical implications of the transition from traditional static cage designs to advanced expandable variants for spinal surgery. The review begins by exploring the early developments in cage materials, highlighting the roles of titanium and polyetheretherketone in the advancement of LIF techniques. This review also discusses the strengths and limitations of these materials, leading to innovations in surface modifications and the introduction of novel materials, such as tantalum, as alternative materials. Advancements in three-dimensional printing and surface modification technologies form a significant part of this review, emphasizing the role of these technologies in enhancing the biomechanical compatibility and osseointegration of interbody cages. In addition, this review explores the increase in biodegradable and composite materials such as polylactic acid and polycaprolactone, addressing their potential to mitigate long-term implant-related complications. A critical evaluation of static and expandable cages is presented, including their respective clinical and radiological outcomes. While static cages have been a mainstay of LIF, expandable cages are noted for their adaptability to the patient's anatomy, reducing complications such as cage subsidence. However, this review highlights the ongoing debate and the lack of conclusive evidence regarding the superiority of either cage type in terms of clinical outcomes. Finally, this review proposes future directions for cage technology, focusing on the integration of bioactive substances and multifunctional coatings and the development of patient-specific implants. These advancements aim to further enhance the efficacy, safety, and personalized approach of spinal fusion surgeries. Moreover, this review offers a nuanced understanding of the evolving landscape of cage technology in LIF and provides insights into current practices and future possibilities in spinal surgery.

Evaluation of the learning curve and complications in unilateral biportal endoscopic transforaminal lumbar interbody fusion: cumulative sum analysis and risk-adjusted cumulative sum analysis

PURPOSE

To evaluate the learning curve and complications in unilateral biportal endoscopic transforaminal lumbar interbody fusion (ULIF) using the Cumulative Sum (CUSUM) analysis and Risk-adjusted Cumulative Sum (RA-CUSUM) analysis.

METHODS

This study retrospectively analyzed 184 consecutive patients who received ULIF in our hospital, including 104 males and 80 females. CUSUM analysis and RA-CUSUM analysis were used to evaluate the learning curve of ULIF based on the operation time and surgical failure rate, respectively. All postoperative complications were defined as surgical failure. Variables of different phases were compared based on the learning curve.

RESULTS

The CUSUM analysis showed the cutoff point for ULIF was 29 cases, and the RA-CUSUM analysis showed the cutoff point for ULIF was 41 cases. Operating time and hospital stay were significantly decreased as the learning curve progressed (P < 0.05). Visual analogue score (VAS) and Oswestry disability index (ODI) at the last follow-up were significantly lower than preoperatively. At the last follow-up, a total of 171 patients reached intervertebral fusion, with a fusion rate of 92.9% (171/184). A total of eleven complications were observed, and RA-CUSUM analysis showed that the incidence of complications in the early phase was 17.07% and in the late phase was 2.6%, with a significant difference (P < 0.05).

CONCLUSION

ULIF is an effective minimally invasive lumbar fusion surgical technique. But a learning curve of at least 29 cases will be required to master ULIF, while 41 cases will be required to achieve a stable surgical success rate.