Open-door laminoplasty with stand-alone autologous bone spacers: evaluation of enlarged laminar arch with CT-multiplanar reconstruction

Laminoplasty in Motion: Evolving Techniques and Complications

Cervical laminoplasty is an increasingly popular surgical option for the treatment of cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL). Over the past few decades, there have been substantial developments in both surgical technique and hardware options. As the field of cervical surgery rapidly evolves, there is a timely need to reassess the evolving complications associated with newer techniques. This review aims to synthesize the available literature on cervical laminoplasty and associated mechanical complications pertaining to different laminoplasty hinge fixation options.

Biomechanical evaluation on a new type of vertebral titanium porous mini-plate and mechanical comparison between cervical open-door laminoplasty and laminectomy: a finite element analysis

Objective: Compare the spine's stability after laminectomy (LN) and laminoplasty (LP) for two posterior surgeries. Simultaneously, design a new vertebral titanium porous mini plate (TPMP) to achieve firm fixation of the open-door vertebral LP fully. The objective is to enhance the fixation stability, effectively prevent the possibility of "re-closure," and may facilitate bone healing. Methods: TPMP was designed by incorporating a fusion body and porous structures, and a three-dimensional finite element cervical model of C2-T1 was constructed and validated. Load LN and LP finite element models, respectively, and analyze and simulate the detailed processes of the two surgeries. It was simultaneously implanting the TPMP into LP to evaluate its biomechanical properties. Results: We find that the range of motion (ROM) of C4-C5 after LN surgery was greater than that of LP implanted with different plates alone. Furthermore, flexion-extension, lateral bending, and axial rotation reflect this change. More noteworthy is that LN has a much larger ROM on C2-C3 in axial rotation. The ROM of LP implanted with two different plates is similar. There is almost no difference in facet joint stress in lateral bending. The facet joint stress of LN is smaller on C2-C3 and C4-C5, and larger more prominent on C5-C6 in the flexion-extension. Regarding intervertebral disc pressure (IDP), there is little difference between different surgeries except for the LN on C2-C3 in axial rotation. The plate displacement specificity does not significantly differ from LP with vertebral titanium mini-plate (TMP) and LP with TPMP after surgery. The stress of LP with TPMP is larger in C4-C5, C5-C6. Moreover, LP with TMP shows greater stress in the C3-C4 during flexion-extension and lateral bending. Conclusion: LP may have better postoperative stability when posterior approach surgery is used to treat CSM; at the same time, the new type of vertebral titanium mini-plate can achieve almost the same effect as the traditional titanium mini-plate after surgery for LP. In addition, it has specific potential due to the porous structure promoting bone fusion.

Analysis of the Risk Factors for C5 Nerve Palsy After Cervical Posterior Open-Door Laminoplasty for Patients with Cervical Spondylotic Myelopathy-From the Perspective of Cervical Sagittal Parameters

OBJECTIVE

This study was performed to explore the sagittal radiological parameters related to the occurrence of C5 nerve palsy after cervical posterior open-door laminoplasty for the patients with cervical spondylotic myelopathy.

METHODS

Sixty-two patients who underwent cervical posterior open-door laminoplasty were reviewed retrospectively from March 2017 to March 2022. The C2-7 Cobb angle, C2-7 sagittal vertex axis, thoracic inlet angle, neck tilt, T1 slope, and encroachment ratio of ossification were measured on X-rays. The enrolled patients were divided into C5 nerve palsy and control groups. Logistic regression was performed to analyze the potential risk factors for the occurrence of C5 nerve palsy. The receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) were used to evaluate the significance of the results and the optimal diagnostic value.

RESULTS

The results of logistic regression showed that only the T1 slope and encroachment ratio were variables that were responsible for C5 nerve palsy (P = 0.024; P = 0.04). The ROC curve analysis for the T1 slope showed that the cutoff value was 21.3° and the AUC was 0.796. The ROC curve analysis for the encroachment ratio revealed that the cutoff value was 0.21 and the AUC was 0.763. Both analyses demonstrated good diagnostic value for C5 nerve palsy.

CONCLUSIONS

The preoperative T1 slope and encroachment ratio were variables that were risk factors for C5 nerve palsy in patients who underwent cervical posterior open-door laminoplasty.