Clinical and Radiological Outcomes in C2 Recapping Laminoplasty for the Pathologies in the Upper Cervical Spine.

OBJECTIVE: To evaluate C2 muscle preservation effect and the radiological and clinical outcomes after C2 recapping laminoplasty. METHODS: Fourteen consecutive patients who underwent C2 recapping laminoplasty around C1-2 level were enrolled. To evaluate muscle preservation effect, the authors conducted a morphological measurement of extensor muscles between the operated and nonoperated side. Two surgeons measured the cross-sectional area (CSA) of obliquus capitis inferior (OCI) and semispinalis cervicis (SSC) muscle before and after surgery to determine atrophy rates (ARs). Additionally, we examined range of motion (ROM), sagittal vertical axis (SVA), neck visual analogue scale (VAS), Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) score to assess potential changes in alignment and consequent clinical outcomes following posterior cervical surgery. RESULTS: We measured the CSA of OCI and SSC before surgery, and at 6 and 12 months postoperatively. Based on these measurements, the AR of the nonoperated SSC was 0.1% ± 8.5%, the AR of the operated OCI was 2.0% ± 7.2%, and the AR of the nonoperated OCI was -0.7% ± 5.1% at the 12 months after surgery. However, the AR of the operated side's SSC was 11.2% ± 12.5%, which is a relatively higher value than other measurements. Despite the atrophic change of SSC on the operated side, there were no prominent changes observed in SVA, C0-2 ROM, and C2-7 ROM between preoperative and 12 months postoperative measurements, which were 11.8 ± 10.9 mm, 16.3° ± 5.9°, and 48.7° ± 7.7° preoperatively, and 14.1 ± 11.6 mm, 16.1° ± 7.2°, and 44.0° ± 10.3° at 12 months postoperative, respectively. Improvement was also noted in VAS, NDI, and JOA scores after surgery with JOA recovery rate of 77.3% ± 29.6%. CONCLUSION: C2 recapping laminoplasty could be a useful tool for addressing pathologies around the upper cervical spine, potentially mitigating muscle atrophy and reducing postoperative neck pain, while maintaining sagittal alignment and ROM.

Evaluation of the Fusion Rate and Safety of Escherichia coli-Derived rhBMP-2 in Transforaminal Lumbar Interbody Fusion for Patients with Degenerative Lumbar Disease: A Prospective, Multicenter, Single-Arm Trial.

Background: Few studies have documented the viability of E. coli-derived recombinant human bone morphogenetic protein-2 (rhBMP-2) in transforaminal lumbar interbody fusion (TLIF). This study aimed to assess the safety and fusion rate of rhBMP-2 in TLIF. Methods: The study was conducted as a prospective, multicenter, single-arm trial, and 30 patients needing one- or two-level TLIF were enrolled. Fusion rate was assessed using the 12-month interbody fusion rate on CT. Postoperative problems, including seroma, radiculitis, and ectopic bone formation, which have been documented as risks associated with rhBMP-2 in prior studies, were recorded. Results: The study demonstrated fusion outcomes in all instances at 52 and 104 weeks post-surgery. Significant improvements were observed in clinical outcomes, with ODI, SF-36, and VAS scores, all achieving statistical significance (p < 0.0001). No perioperative adverse events requiring reoperation were reported, and there were no incidences of seroma, radiculitis, cage migration, grafted bone extrusion, postoperative neurologic deficit, or deep wound infection. Conclusions: The study demonstrates the high safety and efficacy in inducing bone fusion of E. coli-derived rhBMP-2 in TLIF, with a notable absence of adverse postoperative complications. Trial registration: This study protocol was registered at Korea Clinical Research Information Service (number identifier: KCT0004738) on July 2020.

Screw Insertional Torque Measurement in Spine Surgery: Correlation With Bone Mineral Density and Hounsfield Unit.

OBJECTIVE: Achieving successful fusion during spine surgery is dependent on rigid pedicle screw fixation. To assess fixation strength, the insertional torque can be measured during intraoperative screw fixation. This study aimed to explore the technical feasibility of measuring the insertional torque of a pedicle screw, while investigating its relationship with bone density. METHODS: Thoraco-lumbar screw fixation fusion surgery was performed on 53 patients (mean age, 65.5 ± 9.8 years). The insertional torque of 284 screws was measured at the point passing through the pedicle using a calibrated torque wrench, with a specially designed connector to the spine screw system. The Hounsfield units (HU) value was determined by assessing the trabecular portion of the index vertebral body on sagittal computed tomography images. We analyzed the relationship between the measured insertional torque and the following bone strength parameters: bone mineral density (BMD) and HU of the vertebral body. RESULTS: The mean insertion torque was 105.55 ± 58.08 N∙cm and T-score value (BMD) was -1.14 ± 1.49. Mean HU value was 136.37 ± 57.59. Screw insertion torque was positively correlated with BMD and HU in whole patients. However, in cases of osteopenia, all variables showed very weak correlations with insertional torque. In patients with osteoporosis, there was no statistically significant correlation between BMD and torque strength; HU showed a significant correlation. CONCLUSION: The insertional torque of screw fixation significantly correlated with bone density (BMD and HU). HU measurements showed greater clinical significance than did BMD values in patients with osteoporosis.