Minimally Invasive Spine Surgery Research Articles

Learning Curve of Endoscopic Lumbar Discectomy - A Systematic Review and Meta-Analysis of Individual Participant and Aggregated Data.

A systematic review and meta-analysis of individual participant and aggregated data. To define the learning curves of endoscopic discectomies using unified statistical methodologies. Searches returned 913 records, with 118 full-text articles screened. Studies of endoscopic lumbar spine surgery reporting outcomes by case order were included. Mixed-effects nonlinear, logistic, and beta meta-regressions prdwere conducted to define the learning curves. 13 studies involving 864 patients among 15 surgeons were included in total. For transforaminal endoscopic discectomy, the estimated operating time for the first case was 95min [CI: 87-104], and the estimated plateau was 66 minutes [CI: 51-81]. An estimated 21 cases [CI: 18-25] were required to overcome 80% of this deficit, but near-plateau performance was expected only after 59 cases [CI: 51-70]. The estimated risk of surgical complications on the first case was 25% [CI: 11%-46%], with an 80% reduction in relative risk requiring an estimated 41 cases. The expected postoperative VAS leg pain score after the first case was 2.7 [CI: 1.8-3.8], with an 80% improvement requiring an estimated 96 cases. Similar numbers were required to overcome the learning curves in interlaminar and biportal endoscopic discectomies. Approximately 60 cases are required to achieve proficiency in endoscopic lumbar spine surgery, although the greatest part of the learning curve can be overcome with 20 cases. This should be considered when designing implementation programmes for surgeons and service providers that wish to incorporate endoscopic spinal surgery into their practice.

Complications in Minimally Invasive Spine Surgery in the Last 10 Years: A Narrative Review.

Minimally invasive spine surgery (MISS) employs small incisions and advanced techniques to minimize tissue damage while achieving similar outcomes to open surgery. MISS offers benefits such as reduced blood loss, shorter hospital stays, and lower costs. This review analyzes complications associated with MISS over the last 10 years, highlighting common issues and the impact of technological advancements. A systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines was conducted using PubMed, MEDLINE, Embase via OVID, and Cochrane databases, covering publications from January 2013 to March 2024. Keywords related to MISS and complications were used. Studies on adult patients undergoing MISS with tubular, uniportal, or biportal endoscopy, reporting intraoperative or postoperative complications, were included. Non-English publications, abstracts, and small case series were excluded. Data on MISS approach, patient demographics, and complications were extracted and reviewed by 2 independent researchers. The search identified 880 studies, with 137 included after screening and exclusions. Key complications in cervical MISS were hematomas, transient nerve root palsy, and dural tears. In thoracic MISS, complications included cerebrospinal fluid leaks and durotomy. In lumbar MISS, common complications were incidental dural injuries, postoperative neuropathic conditions, and disc herniation recurrences. Complications varied by surgical approach. MISS offers reduced anatomical disruption compared to open surgery, potentially decreasing nerve injury risk. However, complications such as nerve injuries, durotomies, and hardware misplacement still occur. Intraoperative neuromonitoring and advanced technologies like navigation can help mitigate these risks. Despite variability in complication rates, MISS remains a safe, effective alternative with ongoing advancements enhancing its outcomes.

Intraoperative Management of Iatrogenic Durotomy in Endoscopic Spine Surgery: A Systematic Review.

This review aims to systematically evaluate the incidence, management strategies, and clinical outcomes of iatrogenic durotomy (ID) in endoscopic spine surgery and to propose a management flowchart based on the tear size and associated complications. A comprehensive literature search was conducted, focusing on studies involving endoscopic spinal procedures and incidental durotomy. The selected studies were analyzed for management techniques and outcomes, particularly in relation to the size of the dural tear and the presence of nerve root herniation. Based on these findings, a flowchart for intraoperative management was developed. A total of 14 studies were included, encompassing 68,546 patients. Varying incidences of ID, with management strategies largely dependent on the size of the dural tear, were found. Small tears (less than 5 mm) were often left untreated or managed with absorbable hemostatic agents, while medium (5-10 mm) and large tears (greater than 10 mm) required more complex approaches like endoscopic patch repair or open surgery. The presence of nerve root herniation necessitated immediate action, often influencing the decision to convert to open repair. Effective management of ID in endoscopic spine surgery requires a nuanced approach tailored to the size of the tear and specific intraoperative challenges, such as nerve root herniation. The proposed flowchart offers a structured approach to these complexities, potentially enhancing clinical outcomes and reducing complication rates. Future research with more rigorous methodologies is necessary to refine these management strategies further and broaden the applications of endoscopic spine surgery.

Pioneering Promotion in Endoscopic Spine Surgery: Innovation of Fluid Dynamics and Pressure Measurement Models: Commentary on "An Experimental Model for Fluid Dynamics and Pressures During Endoscopic Lumbar Discectomy".

Pioneering Promotion in Endoscopic Spine Surgery: Innovation of Fluid Dynamics and Pressure Measurement Models: Commentary on "An Experimental Model for Fluid Dynamics and Pressures During Endoscopic Lumbar Discectomy".

Postoperative Dysesthesia Secondary to Thermal Injury Following Biportal Endoscopy for Lumbar Canal Stenosis: A Report of 3 Cases and Technical Details of Radiofrequency

Postoperative dysesthesia following lumbar spine surgery is a highly bothersome symptom in the follow-up period. Although many factors contribute to this condition, the most important one is the use of radiofrequency in endoscopic spine surgery. Nonetheless, there is widespread acceptance regarding the use of radiofrequency in endoscopic spine surgery, and the literature contains few reports related to thermal damage to nerves. We describe 3 cases of nondermatomal dysesthesia syndrome in patients who had undergone lumbar unilateral biportal endoscopic surgery for lumbar spinal stenosis. All diagnostic modalities were equivocal, and no pathological lesion was identified. Therefore, we interpreted the dysesthesia as secondary to thermal damage to neural structures, resulting from the radiofrequency.

Commentary on "Intraoperative Management of Iatrogenic Durotomy in Endoscopic Spine Surgery: A Systematic Review".

Commentary on "Intraoperative Management of Iatrogenic Durotomy in Endoscopic Spine Surgery: A Systematic Review".

Lumbar Endoscopic Unilateral Laminectomy for Bilateral Decompression in Degenerative Spondylolisthesis

Degenerative spondylolisthesis is an important cause of chronic low back pain and radiculopathy in the adult U.S. Open decompression with or without fusion is considered the standard for management, yet optimal treatment remains controversial. Full endoscopic spine surgery offers an alternative surgical approach with possible advantages. There is a paucity of data on the use of full endoscopic spinal surgery in degenerative spondylolisthesis. Therefore, we present the clinical and radiographic outcomes of 73 patients with low-grade degenerative spondylolisthesis with severe stenosis, who underwent lumbar endoscopic unilateral laminectomy for bilateral decompression. Patients with low-grade degenerative spondylolisthesis who underwent a lumbar endoscopic ULBD at 6 spine centers in North America were included in this study. Patients were followed up at 3, 9, and 12 months. Static and dynamic imaging was performed and evaluated routinely before surgery to identify the pathology and grade of spondylolisthesis. Patient-reported outcomes were prospectively collected. This study included 73 patients from 6 spine centers. Sixty-two patients were diagnosed with grade I spondylolisthesis, whereas 11 were diagnosed with grade II spondylolisthesis. Postoperatively, 70 patients reported improved symptoms and pain resolution, whereas 3 patients reported worse pain. Mean visual analog scale back and visual analog scale leg scores and Oswestry Disability Index showed a statistically significant improvement at 3, 9, and 12 months compared with the preoperative period. Radiographically, no patient in our study had progression of the grade of spondylolisthesis. Patients with low-grade degenerative spondylolisthesis causing severe stenosis can safely be treated with lumbar endoscopic unilateral laminectomy for bilateral decompression. A head-to-head trial should be undertaken to provide a higher level of clinical evidence.

Letter to the Editor. Evidence for ultra-early outcome of full endoscopic spine surgery

Letter to the Editor. Evidence for ultra-early outcome of full endoscopic spine surgery

Letter to the Editor Regarding “Learning Curve of Biportal Endoscopic Spinal Surgery: A Retrospective 2-Center Study”

Letter to the Editor Regarding “Learning Curve of Biportal Endoscopic Spinal Surgery: A Retrospective 2-Center Study”

Biportal endoscopic en bloc removal of the ligamentum flavum for spinal stenosis: nuances for the "butterfly" technique.

The introduction of endoscopic spine surgery has led to a paradigm shift in the treatment of spinal disorders. In particular, biportal endoscopic surgery has gained traction for its wider visual field and improved the maneuverability of instruments, familiar anatomy, and costeffectiveness. In this study, we describe our en bloc removal of the ligamentum flavum using a "butterfly" technique. This approach had several advantages: (1) The flavum serves as a protective barrier for the dura during drilling. (2) There is less epidural bleeding, which provides (3) better visualization. (4) In an inadvertent durotomy, this usually occurs later in the procedure, which is more manageable than the early stages of decompression. Biportal decompression for spinal stenosis can be performed using an en bloc ligamentum flavum removal technique that is safe, reproducible, and efficient. A systematic approach will help early adopters overcome the steep learning curve.

Placement of 2 cages using navigation-guided biportal endoscopic transforaminal lumbar interbody fusion: illustrative case.

In recent developments, full endoscopic and unilateral biportal endoscopic (UBE) spine surgery have emerged to aid the transforaminal lumbar interbody fusion (TLIF) procedure. Yet, both approaches present a challenge due to limited space for cage insertion, potentially leading to complications such as cage subsidence or nonfusion in long-term assessments. Utilizing double cages may mitigate these concerns. This paper presents a unique case in which a patient successfully underwent computed tomography (CT) navigation-guided UBE-TLIF with 2 converging cages, highlighting the potential benefits and feasibility of this innovative approach. A 59-year-old female diagnosed with degenerative spondylolisthesis at the L4-5 level underwent a UBE-TLIF. The operation is detailed step by step and supported by illustrative figures and surgical videos. Postsurgery results revealed a significant improvement in the patient's condition, with the visual analog scale score decreasing from 7 to 3 on the first day, leading to a satisfaction rate of 90% at the last follow-up. Utilizing endoscopic visualization complemented by contrast medium has substantially elevated the quality of disc preparation. From their observations, the authors affirm that the integration of intraoperative CT navigation systems significantly augments safety and pinpoint accuracy in UBE-TLIF procedures. The strategy of employing 2 converging cages through a unilateral technique stands as a practical solution, potentially optimizing the fusion outcomes of UBE-TLIF surgery. https://thejns.org/doi/10.3171/CASE23512.

Bibliometric Patent Review of Minimally Invasive Spine Surgery.

This study analyzes patents associated with minimally invasive spine surgery (MISS) found on the Lens open online platform. The goal of this research was to provide an overview of the most referenced patents in the field of MISS and to uncover patterns in the evolution and categorization of these patents. MISS has rapidly progressed, with a core focus on minimizing surgical damage, preserving the natural anatomy, and enabling swift recovery, all while achieving outcomes that rival traditional open surgery. While prior studies have primarily concentrated on MISS outcomes, the analysis of MISS patents has been limited. To conduct this study, we used the Lens platform to search for patents that included the terms "minimally invasive" and "spine" in their titles, abstracts, or claims. We then categorized these patents and identified the top 100 with the most forward citations. We further classified these patents into 4 categories: Spinal Stabilization Systems, Joint Implants or Procedures, Screw Delivery System or Method, and Access and Surgical Pathway Formation. Five hundred two MISS patents were identified initially, and 276 were retained following a screening process. Among the top 100 patents, the majority had active legal status. The largest category within the top 100 patents was Access and Surgical Pathway Formation, closely followed by Spinal Stabilization Systems and Joint Implants or Procedures. The smallest category was Screw Delivery System or Method. Notably, the majority of the top 100 patents had priority years falling between 2000 and 2009, indicating a moderate positive correlation between patent rank and priority year. Thus far, patents related to Access and Surgical Pathway Formation have laid the foundation for subsequent innovations in Spinal Stabilization Systems and Screw Technology. This study serves as a valuable resource for guiding future innovations in this rapidly evolving field.

AB075. When would minimally invasive spinal surgery not be preferable for metastatic spine disease?-a narrative review.

Metastatic spine tumour surgery (MSTS) is an important treatment modality of metastatic spinal disease (MSD). Open spine surgery (OSS) was previously the gold standard of treatment. However, advancements in MSTS in recent years has resulted in a current paradigm shift towards today's gold standard of minimally invasive spinal surgery (MISS) and early adjuvant RT in treating MSD patients. Nonetheless, there are still certain situations whereby MISS is not desirable or even suitable. There has also yet to be any literature describing the considerations for not using MISS in MSD in today's clinical context. We aim to bridge the gap where OSS should be considered with caution and highlight situations where MISS is preferable using the available literature and personal experience. This narrative review was conducted using PubMed, Medical Literature Analysis and Retrieval System Online (MEDLINE), The Cochrane Library and Scopus databases through August 31, 2023. Inclusion criteria for the review were studies with discussion on the type of surgery in MSTS. A total of 52 studies were included in this review. We discussed various advantages and situations appropriate for MISS for MSD in today's clinical context. Nonetheless, there are still various unique circumstances in which MISS may be less suitable. MISS is less feasible in patients of paediatric profile, having short stature or having had previous surgery at the level of operation. Occipitocervical and cervicothoracic location of vertebrae metastasis also makes MISS less feasible due to access and imaging difficulty. MISS for tumours which are hypersclerotic and hypervascular can also result in more difficulty for cannulation of MISS probes as well as control of bleeding respectively, and hence will be less encouraged in the above settings. Our review will be the first to discuss circumstances in which MISS is less applicable, despite the advantages it may confer over traditional OSS. MSTS should be individualized to the patient, depending on the experience of the surgeon. OSS is still a time-tested approach that holds weight in MSTS and should be readily utilized depending on the clinical situation.

Enhancing Cadaver Labs for Endoscopic Spine Surgery: The Glove as the “Lesion”

We describe a novel yet simple training exercise for residents who are being introduced to endoscopic spine surgery. Prior to residents training on the endoscopic interlaminar approach, the course faculty performed an endoscopic transforaminal approach and inserted a small piece of a surgical glove into the ventral epidural space of a cadaveric torso. The transforaminal approach did not alter the anatomy of the interlaminar approach so the residents were able to practice as if it were a de novo situation. Placing the small "lesion" provided an exercise to confirm the residents were able to safely access the area and provided practice for them to carefully grasp the "lesion" and remove it. Prior to resident training on the endoscopic transforaminal approach, the course faculty utilized an interlaminar approach to place the "lesion". A questionnaire with a five-point Likert scale of agreement was completed by the residents to assess their experience with the training exercise. Five residents attended the cadaver lab, and 100% strongly agreed that the cadaver lab provided a realistic representation of the procedure demonstrated, the "lesion" removal added to their educational experience, and they were overall satisfied with the educational session. One of the lessons learned with this exercise that we will consider in future courses would be to place a radiodense "lesion" that could be visualized on fluoroscopy, and serve as a radiologic target to find. This can help guide the trainee in knowing where to search if the "lesion" is more difficult to find.

Biportal Endoscopic Spine Surgery for Lumbar Laminectomy and Diskectomy: Postoperative Outcomes and Surgical Learning Curve, a Single US Surgeon's Experience.

Biportal endoscopic spine surgery (BESS) has gained traction for lumbar laminectomy and diskectomy. To justify the transition to BESS, outcomes and the surgical learning curve should be known. This study evaluates rates of complications with BESS and how these rates change with increased surgeon experience. A single surgeon's consecutive patients who underwent BESS were evaluated. Patients older than 18 years who underwent BESS for lumbar laminectomy and diskectomy were included. Patients with previous spine surgery, multiple levels, or BESS for fusion were excluded. Demographics, length of surgery, intraoperative complications, postoperative complications, and revision surgery were recorded. The learning phase group and mastery phase group were based on a cumulative summation analysis based on surgical time. A total of 63 patients, with 31 and 32 patients in the learning and mastery group, respectively, were included. Surgical time decreased from 87 to 52 minutes in the mastery phase. Conversion to open decreased from 3 to 0 cases (P = 0.1803), intraoperative complications decreased from 3 to 0 (P = 0.1803), postoperative complications decreased from 7 to 2 (P = 0.017), and rates of revision surgery decreased from 4 to 1 (P = 0.4233). This study suggests a learning curve of 31 cases for adequate performance of BESS for lumbar laminectomy and diskectomy.

Comparison of Intradural Bupivacaine With Epidural Levobupivacaine in Lumbar Endoscopic Spinal Surgery

Objective: In lumbar endoscopic spinal surgery, the choice of a regional anesthetic is important for reducing complications and can affect patient recovery and comfort.Methods: A retrospective analysis was conducted of 66 lumbar microdiscectomies (LMDs) under epidural anesthesia (EA) (n=45) or intradural anesthesia (IA) (n=21) performed by the same surgeon and anesthesiologist. The choice of regional anesthesia in LMD (epidural or intradural) differs between anesthesiologists, and the most frequently anesthetic method used in LMD is general or IA.Results: EA may be more reliable than IA, as it enables the surgeon to perform a neurological exploration by requesting the patient to make leg or foot movements during surgery, but few studies have compared these 2 anesthetic methods in LMD. We found that there was a statistically significant difference (p<0.05) between the 2 groups in the postoperative recovery times and in the use of vasopressors during surgery.Conclusion: We suggest that EA reduces the length of time to ambulate, length of stay in the postanesthesia care unit, and the time until initiation of postoperative rehabilitation. Compared to IA, it offers greater hemodynamic stability and allows neurological exploration during surgery.

Current Status and Future of Endoscopic Spinal Surgery in Latin America and Spain

Current Status and Future of Endoscopic Spinal Surgery in Latin America and Spain

PL-TOSP, the Novel Entry Point in Transforaminal Endoscopic Spine Surgery: Radiological Analysis with Prospective Surgical Evaluation and Review of Literature of Various Skin Entry Points

Abstract Purpose Aim of this study was to analyze variation in angulation of trajectories of various skin entry points in transforaminal endoscopic spine surgery with change in the physical parameters, namely, weight, abdominal girth, and body mass index and to validate our hypothesis that posterolateral (PL)-tip of spinous process (TOSP) entry has minimal variation in the angle of trajectory as compared with currently available skin entry points. The study included an analysis of the functional outcomes of these patients who underwent transforaminal endoscopy using the novel PL-TOSP technique, assessing improvements in pain and disability. Overview Entry point in transforaminal endoscopic lumbar discectomy (TELD) was taken as a rough distance of 10 to 12 cm from midline as proposed by Kambin whereas Yeung and Tsou advised entry point as distance between the center of the disc space and the posterior skin line measured on lateral. But entry points cannot be static as they tend to change according to changes in physical parameters. Materials and Methods This study comprises of radiological analysis and a prospective evaluation of these patients operated on using the PL-TOSP entry point. Radiological analytic study was performed on 50 symptomatic preoperative patients who underwent transforaminal endoscopy using the novel PL-TOSP entry point. A lumbar spine magnetic resonance imaging (MRI) field of vision (MRI-FOV) was performed for the patients including the abdominal perimeter. Weight, height, and abdominal girth of the patients were noted prior to MRI. Angulation of trajectory made by four standard entry points used in TELD, namely, 45–45, PL, TOSP), dorsum of facet joint, and our proposed entry point PL-TOSP (which is a midpoint between PL and TOSP entry), were calculated using MRI-FOV at L45 and L5S1 level. For the functional outcome analysis of these 50 patients, preoperative Visual Analogue Score (VAS) for lower limb pain and Oswestry Disability Index (ODI) were recorded. Postoperative VAS and ODI scores were reassessed at 2, 6, and 12 weeks. Statistical analysis was conducted to evaluate the significance of changes in VAS scores and ODI preoperative versus postoperative. A p-value of < 0.05 was considered statistically significant. Results Angle of trajectory with the horizontal for all five entry points varies with physical parameters. PL-TOSP entry point has the least variation with change in physical parameters as compared with other entry points. The range of angle for PL-TOSP entry was 21 to 29 degrees. In our study, there was improvement in postoperative VAS and ODI scoring systems which was statistically significant (p-value < 0.05). This suggests reliability of our proposed entry point with consistent postoperative improvement. Conclusion The novel PL-TOSP entry point for transforaminal endoscopy demonstrates superior stability in trajectory angle despite variations in physical parameters, and is associated with significant improvements in functional outcomes and pain reduction for patients with lower limb radiculopathy. Angulation of PL-TOSP trajectory with horizontal also corresponds to current generation of endoscopes (25 or 30 degrees).

Does Routine Post-Operative Use of Drainage in Minimally Invasive Lumbar Spine Surgery Offer Better Results?

Objective: The advantages of minimally invasive spine surgery (MISS) in lumbar degenerative diseases have been well described (less tissue damage, shorter hospital stay, better results in pain assessment). One aspect that has not yet been studied enough is the usage of a post-operative drain in MISS. The aim of this study was to determine whether drainage in MISS is necessary or not and what advantages or disadvantages its use offers. Materials - Methods: We conducted a systematic review of the published literature, searching articles published on Pubmed and Embasse until December 1st 2022, regarding MISS in the lumbar region and post-operative drain usage. Our inclusion criteria were original articles written in English and articles using minimally invasive techniques (usage of tubular retractors along with an endoscope or microscope, paramedian incision, percutaneous screw placement). 42 articles were assessed, and after careful examination and duplication exclusion, 26 research papers were included. Usage, type and duration of postoperative drainage, length of hospital stay, ambulation time and complications were extracted, and relevant results were pooled. Results: The majority of the included articles (80.7 %) reported using a negative-pressure post-operative drain tube. Drains were removed either 48 hours after surgery or when the drainage volume was less than 50ml/24h. Hospital stays and time to ambulation were shorter in cases where drainage was not used. There was no difference in complications between cases where drainage was used and those that it was not. Conclusion: The rationale behind post-operative drainage in MISS is to protect from surgical site infections and hematoma creation. Based on our study there is no evidence to support this hypothesis. On the contrary, our results suggest that the drawbacks of using a drain (pain, discomfort, anxiety, inconvenience of mobilisation, prolongation of hospitalisation) outweigh the advantages, thus making the routine use of postoperative drainage in MISS unnecessary.

The Development of Spinal Endoscopic Ultrasonic Imaging System with an Automated Tissue Recognition Algorithm.

Preclinical experimental study. To develop an intraoperative ultrasound-assisted imaging device, which could be placed at the surgical site through an endoscopic working channel and which could help surgeon recognition of different tissue types during endoscopic spinal surgery (ESS). ESS remains a challenging task for spinal surgeons. Great proficiency and experience are needed to perform procedures such as intervertebral discectomy and neural decompression within a narrow channel. The limited surgical view poses a risk of damaging important structures, such as nerve roots. We constructed a spinal endoscopic ultrasound system, using a 4-mm custom ultrasound probe, which can be easily inserted through the ESS working channel, allowing up to 10 mm depth detection. This system was applied to ovine lumbar spine samples to obtain ultrasound images. Subsequently, we proposed a two-stage classification algorithm, based on a pretrained DenseNet architecture for automated tissue recognition. The recognition algorithm was evaluated using accuracy and consistency. The probe can be easily used in the ESS working channel and produce clear and characteristic ultrasound images. We collected 367 images for training and testing of the recognition algorithm, including images of the spinal cord, nucleus pulposus, adipose tissue, bone, annulus fibrosus and nerve roots. The algorithm achieved over 90% accuracy in recognizing all types of tissues with a Kappa value of 0.875. The recognition times were under 0.1 s using the current configuration. Our system was able to be used in existing ESS working channels and clearly identified at-risk spinal structures in vitro. The pretrained algorithms could identify six intraspinal tissue types accurately and quickly. The concept and innovative application of intraoperative ultrasound in ESS may shorten the learning curve of ESS and improve surgical efficiency and safety.