Cervical Open-Door Laminoplasty by Hydroxyapatite Implant Insertion Without Suturing

Brushite-coated Mg-Nd-Zn-Zr alloy promotes the osteogenesis of vertebral laminae through IGF2/PI3K/AKT signaling pathway

Biodegradable magnesium (Mg) alloys have been extensively investigated in orthopedic implants due to their suitable mechanical strength and high biocompatibility. However, no studies have reported whether Mg alloys can be used to repair lamina defects, and the biological mechanisms regulating osteogenesis are not fully understood. The present study developed a lamina reconstruction device using our patented biodegradable Mg-Nd-Zn-Zr alloy (JDBM), and brushite (CaHPO₄·2H₂O, Dicalcium phosphate dihydrate, DCPD) coating was developed on the implant. Through in vitro and in vivo experiments, we evaluated the degradation behavior and biocompatibility of DCPD-JDBM. In addition, we explored the potential molecular mechanisms by which it regulates osteogenesis. In vitro, ion release and cytotoxicity tests revealed that DCPD-JDBM had better corrosion resistance and biocompatibility. We found that DCPD-JDBM extracts could promote MC3T3-E1 osteogenic differentiation via the IGF2/PI3K/AKT pathway. The lamina reconstruction device was implanted on a rat lumbar lamina defect model. Radiographic and histological analysis showed that DCPD-JDBM accelerated the repair of rat lamina defects and exhibited lower degradation rate compared to uncoated JDBM. Immunohistochemical and qRT-PCR results showed that DCPD-JDBM promoted osteogenesis in rat laminae via IGF2/PI3K/AKT pathway. This study shows that DCPD-JDBM is a promising biodegradable Mg-based material with great potential for clinical applications.

Preoperative Radiological Parameters to Predict Clinical and Radiological Outcomes after Laminoplasty

Many studies have focused on pre-operative sagittal alignment parameters which could predict poor clinical or radiological outcomes after laminoplasty. However, the influx of too many new factors causes confusion. This study reviewed sagittal alignment parameters, predictive of clinical or radiological outcomes, in the literature. Preoperative kyphotic alignment was initially proposed as a predictor of clinical outcomes. The clinical significance of the K-line and K-line variants also has been studied. Sagittal vertical axis, T1 slope (T1s), T1s-cervical lordosis (CL), anterolisthesis, local kyphosis, the longitudinal distance index, and range of motion were proposed to have relationships with clinical outcomes. The relationship between loss of cervical lordosis (LCL) and T1s has been widely studied, but controversy remains. Extension function, the ratio of CL to T1s (CL/T1s), and Sharma classification were recently proposed as LCL predictors. In predicting postoperative kyphosis, T1s cannot predict postoperative kyphosis, but a low CL/T1s ratio was associated with postoperative kyphosis.

Upper Cervical Surgery, Increased Signal Intensity of the Spinal Cord, and Hypertension as Risk Factors for Dyspnea After Multilevel Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective study.

OBJECTIVE

To investigate the associated risk factors for acute respiratory distress after multilevel anterior cervical discectomy and fusion (ACDF) with a focus on the subjective symptom, dyspnea.

SUMMARY OF BACKGROUND DATA

Acute respiratory distress after ACDF is a relatively common adverse event, the cause of which is usually soft tissue swelling or hematoma. It can result in serious morbidity and requires careful, focused treatment.

METHODS

We reviewed the records of 532 patients (from January 2014 to August 2018) who had undergone multilevel ACDF surgery. Acute respiratory distress was defined as a complaint of dyspnea within 5 postoperative days. We investigated the patients' demographic parameters, comorbidities, and surgical procedure details. We also investigated radiologic parameters, including magnetic resonance imaging (MRI), with special attention to the prevertebral soft tissue thickness at C3 and C6. Statistical analysis was performed using the Student's t test and multiple logistic regression analysis.

RESULTS

Out of a total of 484 patients studied after exclusion criteria were applied, 31 patients (6.6%) experienced dyspnea after surgery. We selected 92 patients from the non-dyspnea group and compared them with 31 patients from the dyspnea group. On univariate analysis, upper cervical surgery involving C3, increased cord signal intensity on T2-weighted imaging (T2WI) magnetic resonance imaging (MRI), hypertension, smoking, and prevertebral soft tissue swelling at C3 level on postoperative day 1 were statistically significant factors associated with dyspnea. On logistic regression analysis, upper cervical surgery involving C3, increased cord signal intensity on T2WI MRI, and hypertension were found to be statistically significant variables (P < 0.05).

CONCLUSION

Patients undergoing upper cervical surgery involving C3, and having increased cord signal intensity on T2WI MRI and hypertension need to be monitored more carefully for acute respiratory distress after multilevel ACDF.

LEVEL OF EVIDENCE

4.

Degenerative cervical myelopathy: Recent updates and future directions

Advances in patient selection, surgical techniques, and postoperative care have facilitated spine surgeons to manage complex spine cases with shorter operative times, reduced hospital stay and improved outcomes. We focus this article on a few areas which have shown maximum developments in management of degenerative cervical myelopathy and also throw a glimpse into the future ahead. Imaging modalities, surgical decision making, robotics and neuro-navigation, minimally invasive spinal surgery, motion preservation, use of biologics are few of them. Through this review article, we hope to provide the readers with an insight into the present state of art in cervical myelopathy and what the future has in store for us.

Progression of Cervical Ossification of Posterior Longitudinal Ligament After Laminoplasty or Laminectomy With Posterior Fixation

STUDY DESIGN

Retrospective case analysis.

OBJECTIVE

This study was conducted to investigate the course of ossification of the posterior longitudinal ligament (OPLL) progression after laminoplasty (LP) or laminectomy with posterior fixation (PF).

SUMMARY OF BACKGROUND DATA

LP is now recognized as a standard technique for the treatment of cervical multisegment OPLL; however, PF is beneficial for patients with severe stenosis. In recent years, there has been increasing interest in mechanical stress in OPLL, which is assumed to significantly impact progression.

METHODS

The progression of OPLL was assessed using midline sagittal computed tomography images of the cervical spine at various follow-up points. Radiographic parameters including the C2-C7 Cobb angle, C2-C7 range of motion (ROM), and adjacent cranial and caudal segmental ROMs were measured. Postoperative changes and differences between the LP and PF groups in the radiographic parameters were calculated to assess biomechanical stress. Logistic regression analysis was used to analyze the risk factors affecting the progression rate.

RESULTS

The authors included 14 PF and 36 LP patients, with a mean follow-up period of 28.9±20.8 and 37.6±16.8 months, respectively (P=0.069). After surgical treatment, both groups showed loss of cervical lordosis (9.2±6.9 vs. 5.3±8.2 degrees, P=0.220) and C2-C7 ROM (14.6± 13.5 vs. 13.1±12.2 degrees, P=0.861). The decrease of ROM in the cranial adjacent segment was larger in the LP group than in the PF group (0.7±4.1 vs. 1.4±5.5 degrees, P=0.453). The ROM in the caudal adjacent segment decreased in the LP group but increased in the PF group (-1.4±6.2 vs. 2.6±5.1 degrees, P=0.041). The progression rate was 2.15±1.31 mm/mo in the PF group and 1.53±1.04 mm/mo in the LP group (P=0.041). PF showed an odds ratio of 12.917 for a higher progression rate (95% confidence interval, 1.397-119.443; P=0.024).

CONCLUSION

The rate of progression of cervical OPLL was significantly higher after PF than after LP.Level III-a retrospective analysis.