Yong Ahn

Background and Objectives: Older patients with lumbar spinal stenosis often have comorbidities and limited physiological reserve that complicate conventional decompression under general anesthesia. This study aimed to evaluate the surgical technique and preliminary 1-year clinical outcomes of full-endoscopic unilateral laminotomy for bilateral decompression (FE-ULBD) performed under surgeon-directed local anesthesia. Materials and Methods: This retrospective cohort study included 24 consecutive patients aged ≥ 75 years who underwent FE-ULBD under surgeon-directed local anesthesia for symptomatic central lumbar spinal stenosis between March 2024 and April 2025. Clinical outcomes were evaluated using the visual analog scale (VAS) for leg pain, Oswestry Disability Index (ODI), and modified MacNab criteria. Additionally, perioperative outcomes and complications were analyzed. Results: The mean age of patients was 80.5 ± 3.8 years. The mean VAS scores improved from 8.46 ± 0.72 preoperatively to 2.08 ± 0.83 at 12 months, while ODI scores improved from 68.83% ± 8.07% to 18.34% ± 13.74% (both p < 0.001). Of the 24 patients, 21 (87.5%) achieved excellent or good outcomes. Procedure-related complications included an incidental dural tear in one patient (4.2%) and transient postoperative dysesthesia in 4 patients (16.7%). No major anesthesia-related complications or revision surgeries were observed. Conclusions: FE-ULBD under surgeon-directed local anesthesia was feasible and associated with improvements in pain and function at 12 months in carefully selected older patients. These preliminary findings warrant confirmation in larger prospective studies with a comparator cohort of older patients receiving general anesthesia.

Background/Objectives: Transforaminal endoscopic lumbar foraminotomy (TELF) is increasingly used for lumbar foraminal stenosis, but direct comparisons with open lumbar foraminotomy remain limited. We compared 2-year clinical and perioperative outcomes between the procedures. Methods: We retrospectively reviewed consecutive patients who underwent single-level TELF or open lumbar foraminotomy between January 2020 and January 2024. The primary outcome was the change in leg-pain visual analog scale (VAS) score from baseline to 24 months. Results: Of 159 eligible patients, 147 completed 2-year follow-up (TELF, n = 72; open, n = 75). Improvement in leg-pain VAS score was 5.93 ± 1.60 points after TELF and 5.57 ± 1.44 points after open foraminotomy (mean difference, 0.36; 95% confidence interval, −0.14 to 0.85; p = 0.157). Two-year pain, disability, modified MacNab, complication, and reoperation outcomes did not differ significantly. TELF was associated with a shorter operative time (59.80 ± 15.37 vs. 81.20 ± 21.65 min), hospital stay (1.93 ± 0.68 vs. 6.84 ± 2.85 days), and return-to-work interval among patients who returned to work (3.91 ± 1.20 vs. 8.71 ± 2.45 weeks; all p < 0.001). Conclusions: TELF and open lumbar foraminotomy showed similar observed 2-year clinical outcomes, whereas the TELF treatment pathway was associated with faster perioperative recovery. These observational differences should not be interpreted as equivalence or as effects of surgical technique alone. Complete removal of the medial tip of the superior articular process is presented as a technical consideration for adequate foraminal decompression during TELF; its independent effect on outcomes was not evaluated.

Purpose: This study aimed to describe the predominant pathological patterns observed intraoperatively, the endoscopic decompression techniques used, and the clinical outcomes of transforaminal endoscopic lumbar foraminotomy (TELF) for fusion-segment radicular pain. Patients and Methods: This retrospective descriptive case series included 14 consecutive patients who underwent TELF for unilateral radicular pain caused by foraminal pathology within a previously fused lumbar segment. The compressive pathology was assessed preoperatively using magnetic resonance imaging and computed tomography scan. Then, it was confirmed or further characterized intraoperatively via direct endoscopic visualization. Clinical outcomes were evaluated using the visual analog scale (VAS), Oswestry Disability Index (ODI), and modified MacNab criteria during a 12-month follow-up period. Results: The pathological findings were categorized as perineural adhesion (n = 8, 57.1%), screw-related impingement (n = 4, 28.6%), and foraminal disc herniation (n = 2, 14.3%). The mean VAS score for leg pain decreased from 8.29 ± 0.61 preoperatively to 1.86 ± 1.23 at 12 months postoperatively (p < 0.001). The mean ODI decreased from 71.83% ± 4.79% to 16.89% ± 11.08% (p < 0.001). According to the modified MacNab criteria, 85.7% of the patients achieved excellent or good outcomes. Two patients developed transient postoperative dysesthesia, and one case of incidental dural tear was successfully managed endoscopically. None of the patients required revision fusion or repeat decompression during the 12-month follow-up. Conclusion: TELF may offer a minimally invasive treatment option for fusion-segment radicular pain while preserving the existing fusion construct. Identifying the predominant compressive pathology may facilitate pathology-oriented endoscopic decompression in appropriately selected patients.

Lumbar foraminal stenosis is a common cause of intractable radiculopathy that may require surgical treatment when conservative management is ineffective. Transforaminal endoscopic lumbar foraminotomy (TELF) has been developed as a minimally invasive alternative to conventional open surgery, offering reduced tissue disruption and faster recovery. However, conventional TELF techniques may provide limited decompression in complex cases involving severe bony stenosis, fibrosis, or postoperative anatomical changes. This protocol describes circumferential TELF (C-TELF), an advanced endoscopic decompression technique designed to achieve 360° decompression of the exiting nerve root (ENR) in patients with lumbar foraminal stenosis. The goal of this protocol is to provide a reproducible, step-by-step method for achieving circumferential neural decompression through a landmark-based transforaminal approach. The technique incorporates sequential bony unroofing, soft-tissue removal, and complete neural mobilization within the foraminal zone. The procedure is performed using a percutaneous transforaminal approach under fluoroscopic guidance and endoscopic visualization. Decompression is conducted sequentially from the lower pedicle to the upper pedicle to enlarge the neural foramen and establish an adequate safety margin around the ENR. By achieving circumferential decompression, this technique aims to minimize residual neural compression and facilitate durable decompression. This protocol provides detailed procedural guidance to support the safe and reproducible implementation of C-TELF, particularly in patients with complex or refractory lumbar foraminal stenosis.

Background: Radiculopathy originating from a previously fused lumbar segment is a clinically relevant but often underrecognized problem. Progressive foraminal stenosis may develop due to postoperative structural changes, leading to mechanical irritation of the exiting nerve root. Transforaminal endoscopic lumbar foraminotomy (TELF) is a minimally invasive option, but its role in this setting is not well defined. Methods: In this retrospective cohort study, we included 36 consecutive patients who underwent TELF for symptomatic foraminal stenosis at a previously fused segment between 2020 and 2023. Clinical outcomes were assessed using the visual analog scale (VAS) for leg pain, Oswestry Disability Index (ODI), and modified MacNab criteria, with follow-up of up to 2 years. Radiographic and intraoperative findings were reviewed to explore the underlying mechanisms. Results: The mean VAS score improved significantly from 8.36 preoperatively to 2.00 at 2 years, and the mean ODI decreased from 70.9% to 16.8%. According to the modified MacNab criteria, 86.1% of the patients achieved excellent or good outcomes. Intraoperative findings revealed fibrotic or hypertrophic foraminal stenosis in 86.1% patients (n = 31), whereas 13.9% of patients (n = 5) showed pedicle screw-related nerve root irritation. Five patients experienced transient postoperative dysesthesia, and no postoperative instability was observed. Conclusions: Radiculopathy at the fused segment is primarily caused by progressive mechanical foraminal compromise after fusion. TELF provides effective symptom relief through direct decompression and may serve as a less invasive alternative to revision fusion in selected patients.

Percutaneous vertebroplasty (PVP) and kyphoplasty relieve pain associated with osteoporotic vertebral compression fractures. However, the underlying heterogeneous mechanisms of new-onset and post-vertebroplasty radiculopathy, together with ambiguous imaging findings, can complicate diagnoses. This review summarizes the etiologies, diagnostic processes, and therapeutic roles of full-endoscopic spine surgery (FESS) in treating radiculopathy after vertebroplasty. A comprehensive search of PubMed, Embase and Cochrane Library was performed using the following terms: (“percutaneous vertebroplasty” OR “kyphoplasty”) AND (“radiculopathy” OR “nerve root compression” OR “foraminal stenosis” OR “cement leakage”) AND (“endoscopic spine surgery” OR “full-endoscopic” OR “percutaneous endoscopic” OR “transforaminal endoscopic” OR “TELF” OR “FESS”). Nine of the 428 retrieved studies met the inclusion criteria and were analyzed for etiology, imaging, technique, anesthesia, and outcomes. All included studies were case reports or small case series, and their methodological quality was assessed using established critical appraisal tools for descriptive research. Cement leakage emerged as the main cause of postvertebroplasty radiculopathy, which is managed using FESS via transforaminal or interlaminar approaches. Most patients experienced pain relief and neurological improvement with low perioperative morbidity rates. Endoscopic exploration under local anesthesia may serve as a valuable diagnostic tool to identify and localize neural compression that remains ill-defined on preoperative imaging. Given the limited and heterogeneous nature of the current evidence, conclusions regarding the safety and effectiveness of FESS should be interpreted with caution. Nevertheless, FESS might serve as a feasible diagnostic and therapeutic option when conventional imaging modalities fail to identify the pain generator.

Background/Objectives: Endoscopic lumbar interbody fusion (ELIF) represents a key milestone in minimally invasive spinal surgery, offering reduced tissue trauma, lower complication rates, and faster recovery compared with open fusion. However, its steep learning curve remains a major barrier to widespread adoption. This systematic review aimed to synthesize current evidence on the ELIF learning curve and identify factors that influence the acquisition of surgical proficiency. Methods: A comprehensive literature search of PubMed, Embase, and the Cochrane Library was conducted for studies reporting quantitative analyses of the ELIF learning curve. Eligible articles included clinical data describing operative performance, complication rates, and learning curve cutoff points. Study quality was evaluated using the Newcastle–Ottawa Scale. Pooled data were analyzed to determine the mean cutoff point between the early and proficient phases and to compare outcomes across surgical approaches. Results: Five eligible studies encompassing 425 patients were included. Operative time was the most frequently assessed outcome, followed by hospital stay and complication rates. The pooled cutoff point for operative time was 23.4 ± 8.9 (range, 12–29) cases. Full-endoscopic ELIF tended to require longer operative times but resulted in shorter hospital stays than biportal techniques. Conclusions: ELIF reflects the evolution of endoscopic fusion techniques. The proficiency threshold varies according to the outcome parameters and the type of endoscopic system. Structured training programs and standardized educational pathways are essential for optimizing the learning process and ensuring safe and efficient implementation.

Objectives: Transforaminal endoscopic lumbar foraminotomy (TELF) is an emerging minimally invasive surgical technique for lumbar foraminal stenosis. However, its effectiveness is debated because of concerns regarding adequate decompression and its long-term consistency. This study introduced the extended form of TELF, an advanced technique, to provide more extensive decompression using the same approach. Thus, this study aimed to describe the surgical technique and clinical outcomes of this technique. Methods: This retrospective cohort study included patients who underwent conventional (n = 67) or extended (n = 64) TELF. The surgical procedure involved a transforaminal approach with endoscopic decompression, including the removal of the tip of the superior articular process, foraminal ligament, and ligamentum flavum (conventional group), or additional decompression, involving the isthmus and portions of the superior and inferior pedicle walls (extended group). Clinical outcomes were assessed using the visual analog pain scale, Oswestry disability index, and modified Macnab criteria. Results: Despite the longer surgical duration, the extended TELF group tended to show better outcomes in terms of the VAS and ODI scores at the early and final 2-year follow-ups (p < 0.05). The overall success rates were 92.19% and 85.07% in the extended and conventional groups, respectively. No difference was observed in surgical complications between the two groups. Conclusions: Extended TELF, a refined endoscopic technique, achieves better effects than conventional TELF with a lower risk of nerve root irritation by creating a sufficiently safe resection margin. The results support the use of an extended TELF as an advanced form of endoscopic foraminal decompression.

Endoscopic spine surgery is the perfect culmination of the concept of minimally invasive spine surgery. Among the various endoscopic spine procedures, full-endoscopic spine surgery (FESS) is an endoscopic technique characterized by the performance of the entire spinal procedure via the percutaneous approach using a uniportal working-channel endoscope with continuous saline perfusion. FESS effectively decompresses the tissues and allows for instrumentation while preserving the normal musculoskeletal structures. It also has fewer complications and enables quicker return to work. However, potential disadvantages include its steep learning curves and limited indications. Previously, the indications for endoscopic procedures had been limited to soft disc herniations or focal neural impingement, with most degenerative spinal diseases other than disc herniation being considered contraindications. However, owing to the remarkable advancements in endoscopic technology, nearly all degenerative spinal diseases, including spinal stenosis and instability, can currently be treated using FESS. Furthermore, the application of spinal endoscopes has expanded to other spinal disorders, including infections, traumas, and tumors. Unfortunately, the steep learning curve and technical limitations of FESS cannot be overlooked by most standard spine surgeons. To ensure the clinical success of endoscopic procedures in actual clinical practice, a comprehensive understanding of the core properties of working channel endoscopes is necessary to facilitate the learning process. With the ongoing development of endoscopic technology, endoscopic surgery can be expected to become the standard treatment approach for all degenerative spinal diseases in the near future.

Objectives: Transforaminal endoscopic lumbar foraminotomy (TELF) is an emerging minimally invasive surgical technique for lumbar foraminal stenosis. However, its ef-fectiveness is controversial because of concerns regarding adequate decompression and its long-term consistency. This study introduced the extended form of TELF, an ad-vanced technique, to provide more extensive decompression using the same approach. Accordingly, this study aimed to describe the surgical technique and clinical outcomes of this technique. Methods: This retrospective cohort study included patients who un-derwent conventional (n = 67) or extended (n = 64) TELF. The surgical procedure in-volved a transforaminal approach with endoscopic decompression, including the re-moval of the tip of the superior articular process, foraminal ligament, and ligamentum flavum (conventional group), or additional decompression, involving the isthmus and portions of the superior and inferior pedicle walls (extended group). Clinical outcomes were assessed using the visual analog pain scale, Oswestry disability index, and modi-fied Macnab criteria. Results: Despite the longer surgical duration, the extended TELF group tended to show better outcomes in VAS and ODI at the early and final 2-year follow-ups (P < 0.05). The overall success rates were 92.19% (extended group) and 85.07% (conventional group), respectively. No difference was found in surgical complications between the two groups. Conclusions: Extended TELF, a refined endoscopic technique, achieves better effects than conventional TELF with a lower risk of nerve root irritation by creating a sufficiently safe resection margin. The results support the use of an ex-tended TELF as an advanced form of endoscopic foraminal decompression.