The Lumbar Ligamentum Flavum Does Not Have Two Layers and Is Confluent with the Interspinous Ligament: Anatomical Study with Application to Surgical and Interventional Pain Procedures

A histology guide for performing human cadaveric studies: SQIP 2024 what to look for with light microscopy

Histological observation under light microscopy has long been used in human cadaveric studies. However, it can distort the interpretations of findings if not used appropriately; there is no guide for its proper use. The aim of this article is to revisit and discuss the correct use of histology in human cadaveric studies, following discussions with experts in multiple fields of medicine, and to create the first guide for such usage. We reached a consensus with the experts, agreeing that when this principle (structure, quantification, interaction, position: SQIP) is applied to histological observations, the findings will be interpreted correctly. Appropriate use of this recommendation can make human cadaveric studies more accurate and informative. This is the first histology guide for human cadaveric studies.

Evolution of the term "epicondyle of the femur": Revisiting the anatomical and surgical literature

The femoral epicondyle is an anatomical bony landmark essential for surgeons and anatomists, but there are discrepancies between the two fields when using this term. In current orthopedic surgery, it commonly denotes the small bony prominence of the femoral condyle. Given the derivation, "epicondyle" should be a region projecting laterally from the articular surface rather than a point. These discrepancies in usage are found not only between the fields but also in the literature. This article reviews the narrative definition of "epicondyle of the femur" in surgery and the evolution of the term in anatomy. The outcomes of the review suggest a relationship between the differing perceptions of the epicondyle and the evolution of the term. In reports of studies related to the epicondyle, it is strongly recommended that the definition of the word is clearly stated, with an understanding of its evolution.

Finite element analysis of endoscopic cross-overtop decompression for single-segment lumbar spinal stenosis based on real clinical cases

Introduction: For severe degenerative lumbar spinal stenosis (DLSS), the conventional percutaneous endoscopic translaminar decompression (PEID) has some limitations. The modified PEID, Cross-Overtop decompression, ensures sufficient decompression without excessive damage to the facet joints and posterior complex integrity. Objectives: To evaluate the biomechanical properties of Cross-Overtop and provide practical case validation for final decision-making in severe DLSS treatment. Methods: A finite element (FE) model of L4-L5 (M0) was established, and the validity was verified against prior studies. Endo-ULBD (M1), Endo-LOVE (M2), and Cross-Overtop (M3) models were derived from M0 using the experimental protocol. L4-L5 segments in each model were evaluated for the range of motion (ROM) and disc Von Mises stress extremum. The real clinical Cross-Overtop model was constructed based on clinical CT images, disregarding paraspinal muscle influence. Subsequent validation using actual FE analysis results enhances the credibility of the preceding virtual FE analysis. Results: Compared with M0, ROM in surgical models were less than 10°, and the growth rate of ROM ranged from 0.10% to 11.56%, while those of disc stress ranged from 0% to 15.75%. Compared with preoperative, the growth rate of ROM and disc stress were 2.66%-11.38% and 1.38%-9.51%, respectively. The ROM values in both virtual and actual models were less than 10°, verifying the affected segment stability after Cross-Overtop decompression. Conclusion: Cross-Overtop, designed for fully expanding the central canal and contralateral recess, maximizing the integrity of the facet joints and posterior complex, does no significant effect on the affected segmental biomechanics and can be recommended as an effective endoscopic treatment for severe DLSS.

The Impact of Spine Pathology on Posterior Ligamentous Complex Structure and Function

PURPOSE OF REVIEW

Spinal ligament is an important component of the spinal column in mitigating biomechanical stress. Particularly the posterior ligamentous complex, which is composed of the ligamentum flavum, interspinous, and supraspinous ligaments. However, research characterizing the biomechanics and role of ligament health in spinal pathology and clinical context are scarce. This article provides a comprehensive review of the implications of spinal pathology on the structure, function, and biomechanical properties of the posterior ligamentous complex.

RECENT FINDINGS

Current research characterizing biomechanical properties of the posterior ligamentous complex is primarily composed of cadaveric studies and finite element modeling, and more recently incorporating patient-specific anatomy into finite element models. The ultimate goal of current research is to understand the relative contributions of these ligamentous structures in healthy and pathological spine, and whether preserving ligaments may play an important role in spinal surgical techniques. At baseline, posterior ligamentous complex structures account for 30-40% of spinal stability, which is highly dependent on the intrinsic biomechanical properties of each ligament. Biomechanics vary widely with pathology and following rigid surgical fixation techniques and are generally maladaptive. Often secondary to morphological changes in the setting of spinal pathology, but morphological changes in ligament may also serve as a primary pathology. Biomechanical maladaptations of the spinal ligament adversely influence overall spinal column integrity and ultimately predispose to increased risk for surgical failure and poor clinical outcomes. Future research is needed, particularly in living subjects, to better characterize adaptations in ligaments that can provide targets for improved treatment of spinal pathology.

Percutaneous endoscopic lumbar discectomy via the medial foraminal and interlaminar approaches: A comparative study with 2-year follow-up

OBJECTIVE

The purpose of this study was to analyze the clinical effect of percutaneous endoscopic medial foraminal discectomy (PEMFD) in the treatment of lumbar disc herniation (LDH).

METHODS

We retrospectively examined and compared clinical data from 39 single-level LDH patients who underwent PEID and 47 who underwent PEMFD. All the patients were diagnosed with single-level LDH and were treated in Xuzhou Central Hospital for single-segmental lumbar disc herniation between June 2017 and December 2019. Collect and count surgical-related indicators, intraoperative bleeding volume and 24-hour postoperative drainage volume, lower extremity numbness Visual Analogue Scale (VAS), the pain VAS and lumbar Oswestry Disability Index (ODI) scores.

RESULTS

Intraoperative bleeding volume and 24-hour postoperative drainage volume were significantly lower in the PEMFD group (p < 0.05). Operation time and length of hospital stay did not significantly differ between the groups. Transient spinal cord injury and surgical site infection did not occur. Recurrence occurred in two patients in each group. Repeat surgery in these patients demonstrated remarkable epidural scarring in the PEID group patients; no scarring was evident in the PEMFD group patients. The numbness VAS score 72 h after surgery and the pain VAS and ODI scores 1 month after surgery significantly differed between groups; however, pain VAS and ODI scores 6, 12, and 24 months after surgery did not. At last follow-up, the modified MacNab criteria outcome did not significantly differ between the groups.

CONCLUSION

PEMFD and PEID have similar short- and medium-term outcomes. However, PEMFD has several advantages: simplicity, lower bleeding volume, and preservation of the LF.

Meniscus regeneration by 3D printing technologies: Current advances and future perspectives

Meniscal tears are a frequent orthopedic injury commonly managed by conservative strategies to avoid osteoarthritis development descending from altered biomechanics. Among cutting-edge approaches in tissue engineering, 3D printing technologies are extremely promising guaranteeing for complex biomimetic architectures mimicking native tissues. Considering the anisotropic characteristics of the menisci, and the ability of printing over structural control, it descends the intriguing potential of such vanguard techniques to meet individual joints’ requirements within personalized medicine. This literature review provides a state-of-the-art on 3D printing for meniscus reconstruction. Experiences in printing materials/technologies, scaffold types, augmentation strategies, cellular conditioning have been compared/discussed; outcomes of pre-clinical studies allowed for further considerations. To date, translation to clinic of 3D printed meniscal devices is still a challenge: meniscus reconstruction is once again clear expression of how the integration of different expertise (e.g., anatomy, engineering, biomaterials science, cell biology, and medicine) is required to successfully address native tissues complexities.

Case series of fluoroscopic findings and 3D reconstruction of human spinal MRIs of the space of Okada

OBJECTIVE

To better understand the unexpected spread of contrast medium observed by conventional fluoroscopic X-ray images during standard neuraxial techniques used in the treatment of pain. The support of 3D reconstruction of MRI images of structures within the lumbar spine was used to better understand the space of Okada.

METHODS

Lumbar facet joint and epidural corticosteroid injections in five patients under fluoroscopic guidance with loss of resistance to air or saline to identify the facet joints or epidural space. Next, in a retrospective study, the authors examined the retrodural space of Okada and the neighboring tissues with 3D reconstruction of spinal MRIs of seven patients without any demonstrable spinal pathology to better understand the characteristics of the space of Okada.

RESULTS

Contrast medium spread to the ipsilateral and contralateral sides was observed in five patients. The contralateral spread was thought to be through the retrodural space of Okada, which is a potential space between the anterior surface of the vertebral lamina and the posterior surface of the ligamentum flavum. It facilitates communication between the contralateral articular facet joints of the spine.

CONCLUSIONS

This study provides new evidence for the existence of the space of Okada where an unexpected contralateral spread occurred following facet joint and attempted epidural injection. The 3D reconstructions of MRIs may help us better understand the nature of the retrodural space of Okada and its clinical implications.