Management of a major atlanto-axial instability secondary to a lytic lesion of C2

Comparison of intraoperative CT- and cone beam CT-based spinal navigation for the treatment of atlantoaxial instability

BACKGROUND CONTEXT

Due to the complexity of neurovascular structures in the atlantoaxial region, spinal navigation for posterior C1-C2 instrumentation is nowadays a helpful tool to increase accuracy of surgery and safety of patients. Many available intraoperative navigation devices have proven their reliability in this part of the spine. Two main imaging techniques are used: intraoperative CT (iCT) and cone beam computed tomography (CBCT).

PURPOSE

Comparison of iCT- and CBCT-based technologies for navigated posterior instrumentation in C1-C2 instability.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

A total of 81 consecutive patients from July 2014 to April 2020.

OUTCOME MEASURES

Screw accuracy and operating time.

METHODS

Patients with C1-C2 instability received posterior instrumentation using C2 pedicle screws, C1 lateral mass or pedicle screws. All screws were inserted using intraoperative imaging either using iCT or CBCT systems and spinal navigation with autoregistration technology. Following navigated screw insertion, a second intraoperative scan was performed to assess the accuracy of screw placement. Accuracy was defined as the percentage of correctly placed screws or with minor cortical breach (<2 mm) as graded by an independent observer compared to misplaced screws.

RESULTS

A total of 81 patients with C1-C2 instability were retrospectively analyzed. Of these, 34 patients were operated with the use of iCT and 47 with CBCT. No significant demographic difference was found between groups. In the iCT group, 97.7% of the C1-C2 screws were correctly inserted; 2.3% showed a minor cortical breach (<2 mm); no misplacement (>2 mm). In the CBCT group, 98.9% of screws were correctly inserted; no minor pedicle breach; 1.1% showed misplacement >2 mm. Accuracy of screw placement demonstrated no significant difference between groups. Both technologies allowed sufficient identification of screw misplacement intraoperatively leading to two screw revisions in the iCT and three in the CBCT group. Median time of surgery was significantly shorter using CBCT technology (166.5 minutes [iCT] vs 122 minutes [CBCT]; p<.01).

CONCLUSIONS

Spinal navigation using either iCT- or CBCT-based systems with autoregistration allows safe and reliable screw placement and intraoperative assessment of screw positioning. Using the herein presented procedural protocols, CBCT systems allow shorter operating time.

Management of C2 Body Giant Cell Tumor by Innovatively Fashioned Iliac Crest Graft and Modified Cervical Mesh Cage Used as Plate

BACKGROUND

Locally aggressive vertebral body tumors of the axis must be treated with wide local excision for best outcome. Reconstruction of the load-bearing vertebra needs to be done after tumor resection in such a manner so as to give stable, long-term fusion in this young population.

METHODS

We describe the management strategy of a 25-year-old acutely quadriplegic patient, with respiratory distress, with a C2 giant cell tumor. The use of a novel iliac crest graft modification used for C2 reconstruction along with a modified mesh cage used as an anterior plate has been reported.

RESULTS

The patient had a good outcome at 18 months' follow-up, with neurologic improvement and a solid fusion.

CONCLUSIONS

Iliac crest autograft is inexpensive and easy to harvest and can be considered as a C2 prosthesis, especially in a resource-constrained setting. Modified iliac crest graft can be used for load transmission from C1 lateral mass to C3 body, and the mesh cage can be modified according to need as a plate with good results in an emergency.

Balloon kyphoplasty and additional anterior odontoid screw fixation for treatment of unstable osteolytic lesions of the vertebral body C2: a case series

Background

Unstable osteolytic lesions of the occipitocervical junction are rare and may occur in hematological malignancy or vertebral hemangioma, among others. Different case reports have been published about vertebroplasty for treatment of spinal metastases of the upper cervical spine. Only few cases concern balloon kyphoplasty of C2. We present a consecutive case series including four patients with an osteolytic lesion of the dens axis and describe a technical note for balloon kyphoplasty of C2 and an additional anterior odontoid screw fixation.

Methods

Four consecutive patients with an osteolytic lesion of the vertebral body of C2 were treated by anterior balloon kyphoplasty and additional anterior odontoid screw fixation of the dens axis. The radiological imaging showed a lytic process of the vertebral body C2 with no vertebral collapse but involvement of more than 50% of the vertebral body in all patients.

Results

Two cases of potentially unstable osteolytic lesions of C2 by myeloma, one case with metastatic osteolytic lesion of C2 by adenocarcinoma of the colon and one patient with vertebral hemangioma located in C2 were presented to our clinic. In all cases, surgical treatment with an anterior balloon kyphoplasty of C2 and an additional anterior, bicortical odontoid screw placement was performed. Control x-rays showed sufficient osteosynthesis and cement placement in the vertebral body C2.

Discussion

Anterior balloon kyphoplasty and anterior odontoid screw placement is a safe treatment option for large osteolytic lesions of C2. The additional odontoid screw placement has the advantage of providing more stabilization and may prevent late complications, like odontoid fractures. For patients with potentially unstable or large osteolytic lesions of the dens without spinal cord compression or neurological symptoms we recommend the placement of an anterior odontoid screw when performing a balloon kyphoplasty. Level of evidence: - IV: retrospective or historical series.

Spinal navigation for posterior instrumentation of C1-2 instability using a mobile intraoperative CT scanner

OBJECTIVE Spinal navigation techniques for surgical fixation of unstable C1-2 pathologies are challenged by complex osseous and neurovascular anatomy, instability of the pathology, and unreliable preoperative registration techniques. An intraoperative CT scanner with autoregistration of C-1 and C-2 promises sufficient accuracy of spinal navigation without the need for further registration procedures. The aim of this study was to analyze the accuracy and reliability of posterior C1-2 fixation using intraoperative mobile CT scanner-guided navigation. METHODS In the period from July 2014 to February 2016, 10 consecutive patients with instability of C1-2 underwent posterior fixation using C-2 pedicle screws and C-1 lateral mass screws, and 2 patients underwent posterior fixation from C-1 to C-3. Spinal navigation was performed using intraoperative mobile CT. Following navigated screw insertion in C-1 and C-2, intraoperative CT was repeated to check for the accuracy of screw placement. In this study, the accuracy of screw positioning was retrospectively analyzed and graded by an independent observer. RESULTS The authors retrospectively analyzed the records of 10 females and 2 males, with a mean age of 80.7 ± 4.95 years (range 42-90 years). Unstable pathologies, which were verified by fracture dislocation or by flexion/extension radiographs, included 8 Anderson Type II fractures, 1 unstable Anderson Type III fracture, 1 hangman fracture Levine Effendi Ia, 1 complex hangman-Anderson Type III fracture, and 1 destructive rheumatoid arthritis of C1-2. In 4 patients, critical anatomy was observed: high-riding vertebral artery (3 patients) and arthritis-induced partial osseous destruction of the C-1 lateral mass (1 patient). A total of 48 navigated screws were placed. Correct screw positioning was observed in 47 screws (97.9%). Minor pedicle breach was observed in 1 screw (2.1%). No screw displacement occurred (accuracy rate 97.9%). CONCLUSION Spinal navigation using intraoperative mobile CT scanning was reliable and safe for posterior fixation in unstable C1-2 pathologies with high accuracy in this patient series.

Acute neck pain caused by atlanto-axial instability secondary to pathologic fracture involving odontoid process and C2 vertebral body: treatment with radiofrequency thermoablation, cement augmentation and odontoid screw fixation

INTRODUCTION

Cervical spine metastases are relatively rare entities. Only about 10 % of all spinal metastases can be found in this localization. Magnetic resonance imaging and computed tomography are routinely used for early detection. The initial, clinical examination and patients' complaints may not always be very prominent. Treatment of such lesions is very challenging and needs to consider patient's comorbidities, quality of life and life expectation. Surgery for these lesions should always be performed in specialized spine units.

CASE PRESENTATION

We present here a clinical history of a 67-year-old male with acutely occurring neck pain and some neck discomfort for last 2 weeks. No previous neck pain history or trauma. There were no neurological symptoms, only a slight tremor in the left upper extremity. The detailed past medical history of the patient revealed chronic obstructive pulmonary disease (COPD), diabetes mellitus (DM type II), and smoking 30-pack-year. The first cervical spine X-ray did not demonstrate any pathological findings. We performed a CT scan, which demonstrated a lytic lesion involving the vertebral body of C2 with collapse of odontoid process and subsequent C1-C2 instability. In the next step, because of no medical history of cancer, we performed CT scan of the chest and abdomen, and found a suspicious mass in the right main bronchus and liver. We suggested a bronchial biopsy of the mass but the patient refused this procedure and requested only surgery for the C2 lesion. The patient underwent the described surgical procedure through high anterior cervical approach. We collected the tissue for histology, and performed radiofrequency thermoablation, cement augmentation, and odontoid screw fixation. The patient made an uneventful recovery and 2 weeks after surgery he was able to start his palliative chemotherapy for bronchial carcinoma, which was diagnosed based on biopsy acquired during this procedure.

DISCUSSION

There are no specific guidelines regarding treatment of secondary lesions of C2 with instability at C1-C2 level. We describe here an interesting approach for the management of lytic lesions of C2 which may be used also at other levels of cervical spine. We did not observe any leakage of cement into the spinal canal. This procedure allows for fast recovery of patients, with early unrestricted range of motion, and beginning of early chemotherapy.