Axial spondylectomy and circumferential reconstruction via a posterior approach

Reconstruction of the cervical lateral mass using 3D-printed prostheses

Objective

This study aimed to investigate the outcome of using 3-dimensional (3D)-printed prostheses to reconstruct a cervical lateral mass to maintain cervical stability.

Methods

We retrospectively analyzed data of 7 patients who underwent cervical lateral mass reconstruction using a 3D-printed prosthesis, comprising axial and subaxial lateral mass reconstruction in 2 and 5 patients, respectively. Bilateral mass was reconstructed in 1 patient and unilateral mass in the remaining 6 patients.

Results

Using a 3D-printed lateral mass prosthesis, internal fixation was stable for all 7 patients postoperatively. No implant-related complications such as prosthesis loosening, displacement, and compression were observed at the last follow-up.

Conclusion

Reconstruction of the lateral mass structure is beneficial in restoring load transfer in the cervical spine under physiological conditions. A 3D-printed prosthesis can be considered a good option for reconstruction of the lateral mass as fusion was achieved, with no subsequent complications observed.

A Novel Reconstruction Using a Combined Anterior and Posterior Approach After Axis Tumor Spondylectomy

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To describe a novel reconstruction strategy using a T-shaped titanium mesh cage with posterior cervical screw-rod fixation after total spondylectomy of axis tumors.

SUMMARY OF BACKGROUND DATA

Instability of the upper cervical spine because of tumors in axis (C2) often results in devastating complications. Surgical resection and reconstruction after spondylectomy of C2 remain a technical challenge because of the intricate anatomies, vital adjacent tissues, and the unique spinal biomechanics in this special region.

MATERIALS AND METHODS

The novel reconstruction mode included the construction of the anterior aspect conducted with a specially made titanium mesh cage and the posterior cervical fixation only. Patients who received total C2 tumors spondylectomy and reconstruction with this novel mode in our center between January 2009 and December 2017 were retrospectively analyzed to evaluate the efficacy of this novel reconstruction method.

RESULTS

A total of 24 patients with C2 tumor received total spondylectomy and the new mode of local reconstruction. The neurological deficits recovered well and local pain relieved significantly (P<0.001) during the mean follow-up time of 22 months. Perioperative complications were rare and controllable. No internal fixation failure occurred. The mobility of the occipital-cervical junction was largely preserved in all patients.

CONCLUSIONS

This novel reconstruction mode using an anterior "T-shaped" mesh cage with posterior screw-rod fixation provides satisfactory stability and motion of occipital-cervical junction with limited complications, and therefore may prove to be an ideal option for management of C2 tumors.

LEVEL OF EVIDENCE

Level IV.

Biomechanical evaluation of a novel integrated artificial axis: A finite element study

Various modified instruments are used for the anterior reconstruction of the tumor lesion affecting the second cervical vertebra, but there have been no reports regarding individual integrated artificial axis (IAA) prosthesis fabricated by selective laser melting. In the present work, a new type of IAA prosthesis has been designed with a 3-dimensional (3D) finite element model of normal occiput-the fourth cervical vertebra being established to assess its biomechanics. For easy comparison, another 3D finite element model is also established for the T-shaped Harms cage and an additional posterior fixation was performed on each model. The models are tested under a preliminary loading of 40 N to simulate cervical physical action including flexion, extension, lateral bending, and rotation. Under various loads from 4 different directions, the maximum stress and displacement of the IAA are less than those of the modified T-shaped Harms cage. Except for flexion, the maximum stress of the third cervical vertebra endplate of the IAA is smaller than that of the modified T-shaped Harms cage. The new prosthesis with axis is a good choice for upper cervical operation, which not only can greatly increase the operation stability of the upper cervical segment but also could significantly reduce the risk of fixation failure due to Harms cage subsidence.

Bilateral C-1 lateral mass reconstruction following radical resection of a giant osteoblastoma of the atlas: case report

Osteoblastoma is a rare, benign, osteoid-producing, and slow-growing primary bone tumor, typically arising in long bones or in the spine, with a slight male predominance. This report describes the surgical treatment of a giant C-1 (atlantal) osteoblastoma diagnosed in a young male patient with neurofibromatosis Type 1. The authors describe the clinical presentation, the surgical procedure for complete excision and stabilization, and results as of the 1-year follow-up. They detail a bilateral occipitoaxial spinal interarticular stabilization technique that they used after complete tumor excision. To the best of their knowledge, this is the first case of bilateral C-1 lateral mass reconstruction by this technique to be reported in the literature.

Stabilization of metastatic lesions affecting the second cervical vertebra

PURPOSE

Metastatic spine disease is an ever-increasing burden on health care systems. Certain levels in the spine confer unique biomechanical characteristics and hence are of interest. Isolated C2 lesions are rare. We aimed to review our results in surgical management of C2 lesions.

MATERIALS AND METHODS

We reviewed all surgical stabilizations of metastatic spine lesions over the preceding 4 years. Six patients with C2 lesions were identified. Of these five underwent surgical stabilization primarily for disease affecting the second cervical vertebra. Case notes and radiology were reviewed to determine presentation, outcomes and complications.

RESULTS

Cases were treated primarily by posterior instrumentation from either occiput or C1 to the subaxial cervical spine. The median survivorship after surgery was 283 days. There were no cases of infection, VTE or implant failure. There were no cases of neurologic deterioration with all maintaining Frankel E grading.

CONCLUSION

Metastatic lesions affecting the second cervical vertebra are rare. A variety of stabilization options tailored to the individual lesions, including occipitocervical fixation, in this small series was successful in maintaining stability and resolution of symptoms.

Occipitoaxial spinal interarticular stabilization with vertebral artery preservation for atlantal lateral mass failure

The treatment of craniocervical instability caused by diverse conditions remains challenging. Different techniques have been described to stabilize the craniocervical junction. The authors present 2 cases in which tumoral destruction of the C-1 lateral mass caused craniocervical instability. A one-stage occipitoaxial spinal interarticular stabilization (OASIS) technique with titanium cages and posterior occipitocervical instrumentation was used to reconstruct the C-1 lateral mass and stabilize the craniocervical junction. The ipsilateral vertebral artery was preserved. The OASIS technique offers single-stage tumor resection, C-1 lateral mass reconstruction, and stabilization with a loadsharing construct. It could be an option in the treatment of select cases of C-1 lateral mass failure.