Advantages of Full-endoscopic Trans-Kambin's Triangle Lumbar Interbody Fusion for Degenerative Spondylolisthesis: Illustrative Cases

Advancements in Spinal Endoscopic Surgery: Comprehensive Techniques and Pathologies Addressed by Full Endoscopy Beyond Lumbar Disc Herniation

Endoscopic spine surgery (ESS) has traditionally been employed for lumbar disc herniation (LDH). Recent innovations in surgical methods and technologies have expanded its range to address other spinal pathologies, providing minimally invasive solutions with potential clinical benefits. Our review aims to summarize the applications, clinical outcomes, and limitations of ESS beyond LDH, focusing on its role in complex spinal conditions such as stenosis, thoracic disc herniation, spinal tumors, synovial cysts, and failed back surgery syndrome. A thorough review of the literature was conducted to assess and summarize the current evidence regarding ESS applications for spinal conditions beyond LDH surgery. Areas of focus included innovations in technology and technique, as well as comparisons with conventional open surgical methods. ESS shows notable potential across different spinal conditions by providing minimally invasive alternatives to traditional open surgery. Its use could be associated with reduced surgical morbidity, shorter recovery times, and improved patient outcomes. In particular, ESS is versatile in addressing both degenerative and neoplastic conditions of the spine. Despite this, challenges such as technical complexity, steep learning curves, and limited indications for certain pathologies remain as barriers to wider adoption. ESS is evolving in spine surgery, extending its utility beyond LDH surgery. While the current evidence largely supports its clinical efficacy, further studies are needed to address the present limitations and optimize its application. Future developments in surgical training and technology will likely enhance its adoption and broaden its clinical indications.

Development of New Surgical Training for Full Endoscopic Surgery Using 3D-Printed Models

Introduction

Full endoscopic spine surgery continues to spread worldwide but has a long learning curve. Conventional endoscopy training uses live pigs or human cadavers, which has disadvantages such as high costs and limited availability. Therefore, this study aimed to develop and evaluate three-dimensional (3D)-printed models for endoscopy training.

Methods

Models for 3D printing were generated using raw imaging data from 1.0-mm slices of computed tomography scans, and each part was printed using a different colored material. The combined model was used for training as part of the full endoscopy training kit.

Results

This approach offers several advantages. First, it enables the creation of accurate disease models, such as lumbar disc herniation and other abnormalities, which are useful for both surgical training and preoperative simulations. Second, it is useful for learning surgical orientation. During surgical training, the surgical field can be viewed directly through an endoscope or with the naked eye. By using various colors, it becomes easier to recognize the orientation. Third, the amount of drilling resection can be easily confirmed, facilitating feedback. Finally, training for various surgical techniques is possible, including endoscopic holding techniques and using the endoscope's outer sheath to retract nerves. However, this approach also has some disadvantages, such as the lack of bleeding, inability to reproduce tissue hardness, and difficulty in faithfully recreating soft tissue, such as connective tissue, blood vessels, and fat. Therefore, it is difficult to reproduce the hardness of the calcified disc or disc herniation with apophyseal ring fracture. Moreover, 3D-printed models are not suitable for surgical training using the interlaminal approach because it is difficult to perform separation between the ligamentum flavum and dural matter or between the dural matter and intervertebral disc.

Conclusions

3D-printed models are a useful complement to live pigs and human cadavers in surgical training and can reduce the time required to acquire endoscopic skills.

Full-Endoscopic Posterior Lumbar Interbody Fusion: A Review and Technical Note

Remarkable innovations in spinal endoscopic surgery have broadened its applications over the past 20 years. Full-endoscopic fusions have been widely reported, and several full-endoscopic approaches for interbody fusion have been published. In general, full-endoscopic lumbar interbody fusion (LIF) is called Endo-LIF, and facet-preserving Endo-LIF through the transforaminal route is called trans-Kambin's triangle LIF, which has a relatively longer history than facet-sacrificing Endo-LIF via the posterolateral route. Both approaches can reduce intraoperative and postoperative bleeding. However, there is a higher risk of subsidence and exit nerve root injury. There is no direct decompression in either of the interbody fusions, and additional decompression is required if there is severe lumbar bony canal stenosis. However, the posterior interlaminar approach, which is a well-known standard in full-endoscopic spine surgery, has rarely been applied in the field of endoscopic lumbar fusion surgery. Full-endoscopic posterior LIF (FE-PLIF) via an interlaminar approach can accomplish direct decompression of bony canal stenosis and safe interbody fusion. FE-PLIF via an interlaminar approach demonstrated a longer operation time, less blood loss, and shorter hospitalization duration than minimally invasive transforaminal LIF. FE-PLIF, which can accomplish direct decompression for bony spinal canal stenosis, is superior to other Endo-LIFs. However, FE-PLIF requires technical dexterity to improve efficiency and reduce technical complexity.

Percutaneous transforaminal endoscopic decompression with removal of the posterosuperior region underneath the slipping vertebral body for lumbar spinal stenosis with degenerative lumbar spondylolisthesis: a retrospective study

BACKGROUND

Percutaneous transforaminal endoscopic decompression (PTED) is an ideal minimally invasive decompression technique for the treatment of lumbar spinal stenosis (LSS) with degenerative lumbar spondylolisthesis (DLS). The posterosuperior region underneath the slipping vertebral body (PRSVB) formed by DLS is an important factor exacerbating LSS in patients. Therefore, the necessity of removing the PRSVB during ventral decompression remains to be discussed. This study aimed to describe the procedure of PTED combined with the removal of the PRSVB and to evaluate the clinical outcomes.

METHODS

LSS with DLS was diagnosed in 44 consecutive patients at our institution from January 2019 to July 2021, and they underwent PTED combined with the removal of the PRSVB. All patients were followed up for at least 12 months. The clinical outcomes were evaluated using the visual analog scale (VAS), Oswestry Disability Index (ODI), and modified MacNab criteria.

RESULTS

The mean age of the patients was 69.5 ± 7.1 years. The mean preoperative ODI score, VAS score of the low back, and VAS score of the leg were 68.3 ± 10.8, 5.8 ± 1.0, and 7.7 ± 1.1, respectively, which improved to 18.8 ± 5.0, 1.4 ± 0.8, and 1.6 ± 0.7, respectively, at 12 months postoperatively. The proportion of patients presenting "good" and "excellent" ratings according to the modified MacNab criteria was 93.2%. The percent slippage in spondylolisthesis preoperatively (16.0% ± 3.3%) and at the end of follow-up (15.8% ± 3.3%) did not differ significantly (p>0.05). One patient had a dural tear, and one patient had postoperative dysesthesia.

CONCLUSIONS

Increasing the removal of PRSVB during the PTED process may be a beneficial surgical procedure for alleviating clinical symptoms in patients with LSS and DLS. However, long-term follow-up is needed to study clinical effects.

Clinical Outcome of Full Endoscopic Trans Kambin's Triangle Lumbar Interbody Fusion: A Systematic Review

Full-endoscopic (FE) lumbar interbody fusion (LIF) is now a widely used type of minimally invasive surgery (MIS). Although FE-LIF includes LIF with foraminoplasty via a Kambin's triangle approach (FE-KLIF) and LIF with foraminotomy via an interlaminar approach, these techniques are rarely discussed separately. This review evaluates the outcomes and complications of FE-KLIF reported in the literature. The PubMed, Medline, Embase, Web of Science, and Cochrane Library databases were searched for studies reporting the outcomes of FE-KLIF. Of 464 publications assessed, 11 met our inclusion criteria. Although the most frequently treated level was L4/5, L5/S1 was also treated. FE-KLIF was performed under local anesthesia and sedation or under epidural anesthesia without general anesthesia. Visual analog scale and Oswestry Disability Index scores were improved postoperatively in all uncontrolled studies; however, there was no significant difference in these scores in studies that compared FE-KLIF with posterior LIF (PLIF) or MIS-transforaminal LIF (TLIF). There was also no significant difference in the fusion rate between FE-KLIF and PLIF or MIS-TLIF. In terms of complications, although there were no reports of hematoma, dural tear and surgical site infection were reported in 1 paper each, with transient nerve disorders reported in 5 studies (frequency, 1.8%-23.5%). This review indicates that FE-KLIF is a feasible and viable surgical option for lumbar degenerative disease. However, the amount and level of evidence is low for the studies included in this review, and the data on long-term outcomes remain limited.