How to Prevent Nerve Root Injury in Uniportal Full Endoscopic Lumbar Fusion Surgery? Insights from a Cadaveric Anatomical Study with Simulation Surgery.

STUDY DESIGN: The study included two fresh-frozen cadavers. OBJECTIVE: To elucidate the positional relationship between surgical instruments and nerve roots during full endoscopic facet-sparing (FE fs-TLIF) and facet-resecting (FE fr-TLIF) lumbar interbody fusion and propose safe instrumentation insertion procedures and recommend cage glider designs aimed at protecting nerve roots. SUMMARY OF BACKGROUND DATA: Endoscopic surgical techniques are increasingly used for minimally invasive lumbar fusion surgery with FE fr-TLIF and FE fs-TLIF being common approaches. However, the risk of nerve root injury remains a significant concern during these procedures. METHODS: Eight experienced endoscopic spine surgeons performed uniportal FE fr-TLIF and FE fs-TLIF on cadaveric lumbar spines, totaling 16 surgeries. Post-operation, soft tissues were removed to assess the positional relationship between the cage entry point and nerve roots. Distances between the cage entry point, traversing nerve root, and exiting nerve root were measured. Safe instrumentation design and insertion procedures were determined. RESULTS: In FE fr-TLIF, the mean distance between the cage entry point and traversing nerve root was significantly shorter compared to FE fs-TLIF (3.30±1.35 mm vs. 8.58±2.47 mm, respectively; P<0.0001). Conversely, the mean distance between the cage entry point and the exiting nerve root was significantly shorter in FE fs-TLIF compared to FE fr-TLIF (3.73±1.97 mm vs. 6.90±1.36 mm, respectively; P<0.0001). For FE fr-TLIF, prioritizing the protection of the traversing root using a two-bevel tip cage glider was crucial. In contrast, for FE fs-TLIF, a single-bevel tip cage glider placed in the caudal location was recommended. CONCLUSION: This study elucidates the anatomical relationship between cage entry points and nerve roots in uniportal endoscopic lumbar fusion surgery. Protection strategies should prioritize the traversing root in FE fr-TLIF and the exiting root in FE fs-TLIF, with corresponding variations in surgical techniques. LEVEL OF EVIDENCE: V.

Outcomes of FETD versus UBE in the treatment of L5S1 foraminal stenosis: A comparative study.

Background: The L5S1 level exhibits unique anatomical features compared with other levels. This makes minimally invasive surgery for L5S1 foraminal stenosis (FS) challenging. This study compared the surgical outcomes of full endoscopic transforaminal decompression (FETD) and unilateral biportal endoscopy with the far-lateral approach (UBEFLA) in patients with L5S1FS. Methods: In this retrospective study, 49 patients with L5S1FS were divided into two groups. Of these, 24 patients underwent FETD, 25 patients underwent UBEFLA. The study assessed demographic data, leg pain visual analog scale (VAS) score, back pain VAS score, Oswestry Disability Index (ODI), modified MacNab outcome scale, and radiographic parameters including postoperative lateral facet preservation (POLFP). Results: The Mann-Whitney U test revealed that the UBEFLA group exhibited a higher VAS score for back pain at one week after the operation, whereas the FETD group exhibited a higher leg pain VAS score 6 weeks after the operation. All four undesired MacNab outcomes in the FETD group were attributed to residual leg pain, whereas all five undesired MacNab outcomes in the UBEFLA group were due to recurrent symptoms. Radiographically, the FETD group exhibited greater POLFP. Conclusions: When L5S1FS is performed, there may be challenges in adequately clearing the foraminal space in FETD. On the other hand, UBEFLA allowed for a more comprehensive clearance. However, this advantage of UBEFLA was associated with spinal instability as a future outcome.

Nail-stem construct method for periprosthetic humeral fractures with recalcitrant nonunion after total elbow arthroplasty: A surgical technique.

Objectives: The objective of this study was to describe the surgical technique using an innovative nail-stem construct in treatment of periprosthetic humeral fractures with recalcitrant nonunion after total elbow arthroplasty (TEA). Materials and Methods: Patients diagnosed with humeral recalcitrant nonunion in periprosthetic fractures and stem loosening after TEA were retrospectively recruited between 2018 and 2019. The demographic data and related clinical outcomes were recorded. We use a cutting length of the nail pushing into the humeral canal and then pull back distally to dock the tip of the humeral stem. The cement was packed into the humeral canal, and the periprosthetic bone defect was impacting with harvested allograft chip. Results: Patient age, gender, lesion site, number of previous surgeries, and the time period from the primary TEA to the nail-stem reconstruction were allocated. Moreover, the range of motion, degree of elbow stability, and level of pain were evaluated for each patient following this procedure. All the four patients achieved an optimal range of motion and secure stability with painless elbow at final follow-up. Conclusion: Our proposed nail-stem construct with double allogenous bone plate is a feasible alternative for revisional TEA in patients with implant loosening, periprosthetic humeral fractures, and recalcitrant nonunion.

Full Endoscopic Spine Surgery for Cervical Spondylotic Myelopathy: A Systematic Review.

BACKGROUND: Cervical spondylotic myelopathy (CSM) may seriously affect quality of life. In the literature, there is scarce evidence of the pros and cons of full endoscopic spine surgery in the treatment of CSM. The main purpose of this study was to conduct a systematic review to elucidate the efficacy of full endoscopic spine surgery in the management of patients with CSM. METHODS: This systematic review was conducted in accordance with the PRISMA guidelines. A systematic search of Web of Science, PubMed MEDLINE, Embase, and Cochrane Library was conducted from the database inception to February 1, 2023. RESULTS: The study included 183 patients and their age was 56.78 ± 7.87 years. The average surgical time calculated was 96.34 ± 33.58 minutes. Intraoperative blood loss ranged from a minimal amount to 51 mL. The average duration of hospital stay was 3.56 ± 1.6 days. The average span for follow-up was on an interval of 18.7 ± 6.76 months. Significant improvements were noted in all aspects of functional outcomes and image results after full endoscopic cervical spine surgery, with no major complications. CONCLUSIONS: The current study found that both anterior transcorporeal and posterior surgical approaches could be used for the treatment of CSM with a full endoscopic technique. Indications of full endoscopic cervical spine surgery for CSM included cervical disc herniation, central canal stenosis, calcified ligamentum flavum, and ossification of the posterior longitudinal ligament. Improved postoperative outcomes with acceptable surgical complications were noted in this systematic review.

Comparison of anterior cervical discectomy and fusion versus artificial disc replacement for cervical spondylotic myelopathy: a meta-analysis.

OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) has long been regarded as a gold standard in the treatment of cervical myelopathy. Subsequently, cervical artificial disc replacement (c-ADR) was developed and provides the advantage of motion preservation at the level of the intervertebral disc surgical site, which may also reduce stress at adjacent levels. The goal of this study was to compare clinical and functional outcomes in patients undergoing ACDF with those in patients undergoing c-ADR for cervical spondylotic myelopathy (CSM). METHODS: A systematic literature review and meta-analysis were performed using the Embase, PubMed, and Cochrane Central Register of Controlled Trials databases from database inception to November 21, 2021. The authors compared Neck Disability Index (NDI), SF-36, and Japanese Orthopaedic Association (JOA) scores; complication rates; and reoperation rates for these two surgical procedures in CSM patients. The Mantel-Haenszel method and variance-weighted means were used to analyze outcomes after identifying articles that met study inclusion criteria. RESULTS: More surgical time was consumed in the c-ADR surgery (p = 0.04). Shorter hospital stays were noted in patients who had undergone c-ADR (p = 0.04). Patients who had undergone c-ADR tended to have better NDI scores (p = 0.02) and SF-36 scores (p = 0.001). Comparable outcomes in terms of JOA scores (p = 0.24) and neurological success rate (p = 0.12) were noted after the surgery. There was no significant between-group difference in the overall complication rates (c-ADR: 18% vs ACDF: 25%, p = 0.17). However, patients in the ACDF group had a higher reoperation rate than patients in the c-ADR group (4.6% vs 1.5%, p = 0.02). CONCLUSIONS: At the midterm follow-up after treatment of CSM, better functional outcomes as reflected by NDI and SF-36 scores were noted in the c-ADR group than those in the ACDF group. c-ADR had the advantage of retaining range of motion at the level of the intervertebral disc surgical site without causing more complications. A large sample size with long-term follow-up studies may be required to confirm these findings in the future.

Ameliorated Full-Endoscopic Transforaminal Decompression for L5-S1 Foraminal and Extraforaminal Stenosis.

STUDY DESIGN: This is a retrospective review. OBJECTIVE: To describe a modified surgical technique, full-endoscopic transforaminal decompression (FETD) in patients with L5-S1 foraminal stenosis or extraforaminal stenosis (EFS) and to detail the short-term results. SUMMARY OF BACKGROUND DATA: Performing FETD surgery for L5-S1 FS and EFS is challenging because of high iliac crests in most cases and the difficulty in accurately differentiating between FS and EFS by images preoperatively. MATERIAL AND METHODS: Patients who had solitary unilateral L5-S1 FS or EFS and had undergone FETD between October 2014 and December 2017 were included. In total, 22 patients underwent FETD for L5 root compressions at the L5-S1 levels. All patients were followed up for more than 1 year. RESULTS: The mean visual analog scale score for back and leg pain, assessed preoperatively and at 12 months postoperatively, improved from 6.3±1.7 to 1.59±1.30 and from 7.29±0.78 to 1.41±1.20, respectively. The mean Oswestry Disability Index improved from 61.53% preoperatively to 15.8% at 12 months postoperatively. Neurovascular injury-related complications were absent in all these cases. CONCLUSION: Successful short-term clinical outcome is achievable using the ameliorated FETD technique for treating L5-S1 FS and EFS.

Full endoscopic interlaminar discectomy (FEID) for recurrent lumbar disc herniation: surgical technique, clinical outcome, and prognostic factors.

BACKGROUND: The objective of this study is to determine the effectiveness and prognostic factors of revisional full endoscopic interlaminar discectomy (FEID) for recurrent herniation after conventional open disc surgery. The major concerns of the repeated discectomy for recurrent lumbar disc herniation (RLDH) are the epidural scar and postoperative segmental instability. Compared to open discectomy, endoscopic method has advantages of less tissue traumatization, clearer visualization and better tissue identification. With the improvement of endoscopic technique and instrument, the problems related to adhesive scar tissues or postoperative instability could be overcome. METHODS: From June 2014 to December 2016, FEID was performed in consecutive 24 patients for RLDH. The age ranged from 25 to 60 years (mean 44.6 years). The level operated was L5-S1 in 16 cases and L4-5 in 8 cases. To avoid injury to the neural tissue, we started with the bony structure. A small part of facet or lamina might be resected in severe stenotic or adhesive condition. Aggressive separation of the scar from the neural tissue might lead to dural tear and should be avoided. The herniated disc material was removed after neural tissue had been clearly identified and protected. RESULTS: The follow-up period was at least 24 months. The visual analog scale (VAS) for leg pain and back pain, and Oswestry disability index (ODI) showed significant improvement after treatment. Excellent or good outcome by the modified Macnab's criteria was obtained in 22 of 24 patients at two years follow-up. Excellent outcome was noted in 100 percent patients younger than 50 years. Small durotomy occurred in 2 patients and no visible cerebrospinal fluid (CSF) leakage was detected despite repair was not performed. Two additional surgery was performed including one repeated FEID for re-recurrence of disc herniation and one fusion surgery for postoperative back pain. CONCLUSIONS: FEID is a safe and effective alternative for recurrent disc herniation. The successful rate was greater than 90 percent, especially in the younger patients with the advantages of early recovery and no need for fusion.

Using Percutaneous Endoscopic Outside-In Technique to Treat Selected Patients with Refractory Discogenic Low Back Pain.

BACKGROUND: Controversy is not uncommon in the diagnosis of discogenic low back pain (DLBP) and in the identification of the location of the pain source for the symptomatic disc in patients with DLBP. Various techniques, from minimally invasive procedures to fusion surgery, are used to treat chronic DLBP, but the clinical outcomes are variable. Percutaneous endoscopic discectomy by transforaminal or interlaminar approach is considered to be an effective method to treat DLBP, but the evidence is limited; the lack of clear evidence may be associated with patient selection and surgical technique. OBJECTIVES: The purpose of this study is to evaluate the clinical results of percutaneous endoscopic treatment for annular tear in selected patients with DLBP by using the outside-in technique. STUDY DESIGN: A prospective study and retrospective observations were performed on 24 consecutive patients with a minimum 2 years of follow-up. This study was approved by the Institutional Review Board (IRB) of Buddhist Dalin Tzu-Chi General Hospital Foundation (IRB number: 10504004) and written informed consent was obtained from all patients. SETTING: This research took place within an interventional pain management and spine practice. METHODS: Twenty-four consecutive patients with single-level DLBP diagnosed by positive high-intensity zone on magnetic resonance imaging, positive provocative discography, and block test underwent a percutaneous endoscopic procedure from January 2014 to December 2015. The transforaminal approach or interlaminar approach was selected according to the location of the annular tear. The torn lesions were visualized directly and treated by puncture and debridement of the inflammatory tissues from the outer annulus fibrosus to the inner nucleus using the outside-in technique. The Visual Analog Scale (VAS) score and Oswestry Disability Index (ODI) score were evaluated before and after surgery. The clinical global outcomes were assessed on the basis of modified MacNab criteria. RESULTS: These patients included 13 men and 11 women with a mean age of 43.8 years (range, 32-55 yrs). There were 15 lesion levels at L4/L5 and 9 lesion levels at L5/S1. Among them, 15 levels were accessed by transforaminal approach and 9 levels by interlaminar approach. No serious complications were observed during the follow-up periods. All except 2 patients experienced significant symptomatic and functional improvements at the 2-year follow-up with a success rate of 91.7%. LIMITATIONS: Significant limitations include nonrandom format and small sample size. Future research may focus on controlled prospective studies with larger sample sizes and long-term follow-up to examine the validity of this protocol. CONCLUSIONS: The percutaneous endoscopic procedure provides a safe and effective treatment for selected patients with DLBP. The outside-in technique allows the surgeons to visualize and treat the torn or inflammatory lesions directly, and the success rate is high at 2 years follow-up. KEY WORDS: Transforaminal, interlaminar, outside-in technique, endoscopic discectomy, discogenic low back pain.

Modified fixations for distal femur fractures following total knee arthroplasty: a biomechanical and clinical relevance study.

PURPOSE: Distal femur fractures adjacent to total knee arthroplasty are a rare yet complex problem. Recently, extramedullary locking plate and retrograde intramedullary nail fixations have become popular options, but the complication rates associated with these procedures are 15-20 %. Modified fixations were assessed in an effort to reduce complications from unstable periprosthetic fractures. METHODS: Using experimental and finite element methods, this study compared the construct behaviours of a locking plate, a retrograde intramedullary nail, and their modifications (a spiral-blade supplemented in an intramedullary nail or a locking plate/allograft hybrid) when subjected to various fracture types, locations, loading conditions, and bony strength. The implanted models were used to assess construct stiffness, fracture micromotion, and implant stress under different osteoporotic conditions. Finally, we collected 40 cases for radiological analysis to indicate the appropriate procedure for treating periprosthetic fractures following total knee arthroplasty. RESULTS: Regardless of the fracture type, femoral constructs fixed with a conventional or spiral-blade supplemented intramedullary nail exhibited higher axial but lower torsional stiffness than those fixed with a locking plate. Torsional deformation occurred if the lower-positioned fracture had no medial support. The locking plate/allograft construct exhibited the highest stiffness and the least micromotion. A review of 40 clinical cases confirmed the above findings regarding the locking plate/allograft construct. CONCLUSION: The spiral-blade supplement of retrograde intramedullary nail and locking plate/allograft modified constructs significantly stabilizes the unstable fractured gaps. The locking plate/allograft is recommended for the periprosthetic fractures with deficient bone stock and severe osteoporosis to improve alignment and healing potentials.

Higher incidence of rheumatoid arthritis in patients with symptomatic osteoarthritis or osteoarthritis-related surgery: a nationwide, population-based, case-control study in Taiwan.

OBJECTIVES: To investigate the risk of incident rheumatoid arthritis in patients with symptomatic osteoarthritis or osteoarthritis-related surgery using a nationwide health claims database. DESIGN: A nationwide, population-based, case-control study. SETTING: Taiwan's National Health Insurance Research Database. PARTICIPANTS: A total of 1147 patients (aged 20-100 years) with rheumatoid arthritis and 5735 controls who were frequency-matched for sex, 10-year age interval and year of catastrophic illness certificate application date (index year) were identified. MAIN OUTCOME MEASURE: All participants were retrospectively traced, up to 14 years prior to their index year, for diagnosis of osteoarthritis or osteoarthritis-related surgery. Multivariate logistic regression analyses were conducted to quantify the association between rheumatoid arthritis and osteoarthritis. RESULTS: The risks of rheumatoid arthritis were significantly higher in patients with symptomatic osteoarthritis (adjusted OR=5.24, p<0.001) and osteoarthritis-related surgery (adjusted OR=2.27, p<0.001). CONCLUSIONS: This large nationwide, population-based, case-control study showed a higher risk of rheumatoid arthritis in Taiwanese patients with symptomatic osteoarthritis. Our findings were consistent with the hypothesis that osteoarthritis might be a triggering factor of rheumatoid arthritis in environment-sensitised and genetically susceptible individuals.