Neurospine最新文献

Objective: Retro-odontoid pseudotumor (ROP) is a nonneoplastic mass associated with atlantoaxial instability (AAI). This study compared ROP-positive and ROP-negative AAI patients and evaluated cystic versus granulation-type ROP regarding regression patterns and surgical outcomes.

Methods: We retrospectively analyzed 112 AAI patients who underwent pre- and postoperative imaging and clinical evaluations. Patients were classified as ROP-positive or ROP-negative, with ROP-positive cases further categorized as cystic or granulation-type. Imaging parameters-including atlantodental interval (ADI), ΔADI, and cervical range of motion (ROM) were compared along with regression time and postoperative outcomes.

Results: Among 112 patients, 57 (50.9%) had ROP. The ROP-positive group was older (67.37±13.13 years vs. 56.90±15.15 years, p<0.001) and had lower ADI (5.63±2.77 mm vs. 6.99±2.33 mm, p=0.034), ΔADI (3.01±2.27 mm vs. 3.89±2.07 mm, p=0.006), and C2-7 ROM (30.78°±15.45° vs. 41.73°±16.58°, p<0.001). In ROP subgroups, the cystic group had greater C1-2 ROM (15.69°±6.34° vs. 10.00°±7.72°, p=0.013) and ADI (6.98±2.68 mm vs. 5.14±2.66 mm, p=0.042). Immediate postoperative ROP thickness remained greater in the cystic group (6.85±2.49 vs. 5.21±1.82 mm, p=0.042), while ROP thickness at 3 months and 1 year showed no significant differences. JOA recovery rates were similar.

Conclusion: This study demonstrates that ROP-positive AAI patients exhibit distinct radiological characteristics, with reduced cervical mobility. Furthermore, cystic ROP shows delayed regression following posterior fusion. These findings underscore the importance of ROP subtypes in surgical planning, requiring closer monitoring and possibly earlier intervention.

Objective: To develop a pedicle screw for posterior spinal fixation using this long fiber carbon fiber reinforced plastic (CFRP) technology and evaluate its strength and radiolucency compared with titanium (Ti)-alloy screws.

Methods: In this preclinical study, the shear strength, torsional strength, loosening resistance, and image evaluation of long fiber type CFRP pedicle screws and Ti-alloy screws were compared. A series of tests was conducted for future clinical-use approval.

Results: The long fiber type CFRP pedicle screw (mean±standard deviation: 11,377.7±245.1 N) had superior shear strength compared to the Ti-alloy pedicle screw (10,300.3±249.7 N). The long fiber type CFRP pedicle screw (4.4±0.5 Nm) had inferior torsional strength compared to the Ti-alloy pedicle screw (22.4±0.6 Nm), although it could withstand twice the maximum load applied during surgery, suggesting that this will not be a clinical concern. In terms of loosening resistance, maximum torque values of the long fiber type CFRP pedicle screw and Ti-alloy pedicle screw were 0.99±0.08 and 0.75±0.05 Nm, respectively. The long fiber type CFRP pedicle screw was significantly more resistant to loosening than the Ti-alloy pedicle screw. Moreover, artifacts in the radiographic images were smaller than those observed for the Ti alloy. Biosafety and magnetic resonance safety tests also yielded satisfactory results, supporting approval of the long fiber CFRP pedicle screws for clinical use.

Conclusion: Compared to existing Ti-alloy screws, the long fiber type CFRP pedicle screw with innovative manufacturing technology has sufficient performance for clinical use, and its use may make spinal surgery safer and more effective.

Objective: To analyze long-term clinical and radiological outcomes after multilevel anterior osteotomy with posterior instrumentation in patients with ossification of posterior longitudinal ligament (OPLL)-induced myelopathy and cervical kyphosis.

Methods: Patients who underwent multilevel anterior osteotomy with posterior instrumentation for OPLL-induced myelopathy and cervical kyphosis and had a minimum of 5-year follow-up were included. Clinical outcomes (Japanese Orthopaedic Association score system for cervical myelopathy [C-JOA], 12-item Short Form health survey [SF-12], Neck Disability Index [NDI]) and radiological parameters (C2-7 lordosis, center of gravity of the head [CGH]-C7 sagittal vertical axis [SVA], T1 slope) were analyzed at the preoperative, immediate postoperative, and latest follow-up timepoints.

Results: Twenty-eight patients were included. The average follow-up period was 66.4 months. All clinical outcome parameters showed significant improvement. C-JOA, SF-12, and NDI showed significant improvement at latest follow-up (p<0.001). C2-7 lordosis increased significantly immediately postoperatively (-6.0°±10.4°) compared to preoperatively (+9.2°±9.6°), and was largely maintained at latest follow-up (-5.7°±9.4°). T1 slope significantly increased between the immediate postoperative timepoint (21.9°±7.7°) and latest follow-up (24.2°±9.5°) (p=0.046). CGH-C7 SVA significantly increased between the immediate postoperative timepoint (22.7±14.8 mm) and latest follow-up (32.2±22.6 mm) (p=0.046).

Conclusion: Multilevel anterior osteotomy with posterior instrumentation is a safe and effective surgical option for OPLL-induced myelopathy with kyphotic cervical alignment. Future studies are required to investigate the forward tilting of cervical spine over time after surgery.

H. Chiari described 4 types of abnormal development of the posterior fossa, which were subsequently classified as Chiari malformation types I, II, III, and IV. Many issues in neurosurgery concerning classification and surgical management are without evolving concepts. This review aims to clarify the mechanisms and pathogenesis underlying hindbrain (the brain stem and cerebellum) descent, classify them accordingly, and discuss appropriate surgical management. We propose a classification of 4 independent pathogenic mechanisms: (1) constriction in the posterior cranial fossa (PCF) due to underdevelopment of the occipital bone; (2) enlargement of hindbrain; and (3) traction caused by tethering lesions. We examine the pathogenesis of hindbrain descent from embryological perspectives and neuroradiological findings, with a particular focus on lesser-known mechanisms. Additionally, another fourth mechanism is proposed: (4) instability at the craniocervical junction. We suggest a novel classification for Chiari malformation type I based on the underlying pathogenesis, guided by morphometric (occipital bone size) and volumetric (PCF volume) analyses. Furthermore, it delves deeper into their pathogenesis by drawing on insights from developmental biology, genetic studies, and experimental research. Surgical management is tailored to the underlying mechanism, and we proposed the algorithm for decision of surgical intervention. For crowding of the PCF due to underdevelopment of the occipital bone, posterior fossa decompression is the appropriate surgical intervention. For craniocervical instability, occipitocervical fixation is recommended. We also review the recent literature on surgical outcomes associated with each treatment approach. Finally, we highlight current genetic research related to the pathogenesis of hindbrain descent.

Objective: Unilateral biportal endoscopic (UBE) spine surgery is a minimally invasive technique that uses continuous irrigation to improve visualization and control bleeding. Effective water pressure management is crucial for patient safety, particularly at the cervical and thoracic levels where spinal cord injury risk is higher. However, real-time pressure monitoring remains underexplored. This study evaluates the impact of real-time water pressure monitoring on safety during UBE surgery.

Methods: A prospective study was conducted involving 20 patients undergoing UBE lumbar spine surgery. Patients were divided into 2 groups based on the irrigation system: gravity-based or infusion pump. Real-time water pressure was monitored using a digital sensor throughout surgery. Each procedure was categorized into 3 phases: phase I, working space preparation; phase II, laminectomy; phase III, flavectomy, dura exposure, and discectomy. Data was analyzed according to the type of irrigation system and surgical phase.

Results: The mean water pressure in the surgical field during UBE spine surgery was 17.98± 8.07 mmHg, with no significant differences between surgical phases. However, the infusion pump system maintained significantly lower mean pressure (12.10±3.51 mmHg) compared to the gravity-based system (23.86±6.97 mmHg, p=0.001). The infusion pump system consistently maintained a significantly lower mean water pressure compared to the gravity-based system.

Conclusion: Real-time water pressure monitoring during UBE surgery enhances safety by enabling improved control of pressure within the surgical field. Both the gravity-based and infusion pump systems safely maintained working space pressure, with the pump system showing significantly lower pressure levels.