Evaluation and Surgical Planning for Craniovertebral Junction Deformity

Craniovertebral Junction Deformity Diagnosed by Computed Tomography: A Case Report

Craniovertebral junction (CVJ) deformities, including basilar invagination and atlanto-occipital assimilation, present significant challenges in diagnosis and management due to their complex nature and impact on neurological function. We report a case of a 28-year-old female who experienced neck pain, weakness, tingling in the upper limbs, restricted neck movements, occipital headaches, and intermittent dizziness. These symptoms progressively worsened over six months, markedly affecting her quality of life. Neurological examination revealed reduced motor power in the upper limbs and a diminished bicipital tendon reflex, while other assessments remained normal. Cervical spine CT imaging was done which revealed basilar invagination and atlanto-occipital assimilation. This case underscores the importance of recognizing and managing CVJ deformities, highlighting the need for a multidisciplinary approach to address anatomical and associated neurological symptoms. Early and accurate diagnosis and a tailored treatment strategy are crucial for improving patient outcomes.

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.

Cervical sagittal parameters in degenerative cervical spondylolisthesis versus degenerative cervical kyphosis with myeloradiculopathy treated by anterior cervical discectomy and fusion

Background

Adult spinal deformity, especially sagittal imbalance, is affecting health-related quality-of-life (HRQOL) scores. There is a lack of emphasis in the comparison of cervical sagittal parameters in patients with degenerative cervical spondylolisthesis and degenerative cervical kyphosis. The aim of study is to determine the preoperative and postoperative cervical sagittal parameters in myeloradiculopathic patients with degenerative cervical spondylolisthesis and degenerative cervical kyphosis treated by anterior cervical discectomy and fusion (ACDF).

Methods

A retrospective medical records and radiographic study of 30 adult patients were reviewed. Fifteen patients with degenerative cervical spondylolisthesis and 15 patients with degenerative cervical kyphosis have been performed ACDF from 2010-2020. We measured the preoperative and postoperative cervical sagittal parameters: C0-C2 angle, C1-C2 angle, C2-C7 angle, C2-C7 sagittal vertical axis (SVA), T1 slope, neck tilt angle and thoracic inlet angle. Minimum follow-up period was at least 2 years.

Results

Patients in degenerative cervical kyphosis group have C2-C7 angle less than degenerative cervical spondylolisthesis group (-14.88±7.32 vs. 9.60±13.60), leading to increase the mismatch between T1 slope and C2-C7 angle in kyphotic group and hyperlordosis of C0-C2 angle and C1-C2 angle (31.13±7.68, 37.88±5.08) compare with spondylolisthesis group (13±10.20, 24.60±10.70). Whereas patients with degenerative cervical spondylolisthesis have C2-C7 SVA (33.22±13.92) more than kyphosis group (13.70±13.60). After surgery, there is significant increase of the C2-C7 angle in the kyphosis group compare before and after surgery (-14.88±7.32 vs. 4.10±11.80). While the spondylolisthesis group has no significantly different parameters compare to before surgery. However, the postoperative cervical sagittal parameters of all patients are within the normal thresholds (T1-Slope minus C2-C7 lordosis <15° and C2-C7 SVA <40 mm).

Conclusions

The study demonstrates the difference of sagittal parameters between degenerative cervical spondylolisthesis and kyphosis before and after surgery. ACDF not only provides neural decompressive procedure, but also corrects the regional cervical sagittal parameters.

Novelties for increased safety in cranio-vertebral surgery: a review

The cranio-vertebral junction (CVJ) was formerly considered a surgical "no man's land" due to its complex anatomical and biomechanical features. Surgical approaches and hardware instrumentation have had to be tailored in order to achieve successful outcomes. Nowadays, thanks to the ongoing development of new technologies and surgical techniques, CVJ surgery has come to be widely performed in many spine centers. Accordingly, there is a drive to explore novel solutions and technological nuances that make CVJ surgery safer, faster, and more precise. Improved outcome in CVJ surgery has been achieved thanks to increased safety allowing for reduction in complication rates. The Authors present the latest technological advancements in CVJ surgery in terms of imaging, biomaterials, navigation, robotics, customized implants, 3D-printed technology, video-assisted approaches and neuromonitoring.

Role of Posterior Longitudinal Ligament Complex in Spinal Deformity Secondary to Surgical Resection of the Intradural Tumor

OBJECTIVE

In most cases, complete resection of the intradural tumor is accompanied by long-term neurological complications. Postoperative spinal deformity is the most common complication after surgical resection of intradural tumors, and posterior longitudinal ligament complex (PLC) plays an important role in postoperative spinal deformity. In this study, we investigated the role of PLC in spinal deformity after the surgical treatment of intradural tumors.

METHODS

We analyzed the data of 218 consecutive patients who underwent intradural tumor resection from 2000 to 2018 in this retrospective study. Before 2010, patients underwent laminoplasty without maintaining the integrity of PLC (laminoplasty group, n = 155). After 2010, patients performed single-port laminoplasty to maintain the integrity of PLC (laminoplasty retain posterior ligament complex group, n = 63). The score of quality of life, painful cortex, spinal cord movement, progressive kyphosis or scoliosis, perioperative morbidity, and neurological results were analyzed in the laminoplasty group and laminoplasty retain posterior ligament complex group. The distributed variable was shown as mean ± standard deviation and an independent t-test or one-way analysis of variance was calculated.

RESULTS

There are 155 patients (71.1%) included in the laminoplasty group, and 63 patients (28.9%) in the laminoplasty retain posterior ligament complex group. The average age of patients was 42 ± 2.3 years, and the average modified McCormick score was 2. There were 158 (72.4%) patients with intramedullary tumors and 115 (52.7%) patients with extramedullary tumors. The length of hospital stays (8 days vs. 6 days; p = 0.023) and discharge to inpatient rehabilitation (48.4% vs. 26.9%; p = 0.012) were significantly lower in the laminoplasty retain posterior ligament complex group than the laminoplasty group. There was no significant difference in the risk of progressive deformity between the two groups at 18 months after surgery (relative risk 0.12; 95% confidence interval [CI] 0.43-1.25; p = 0.258) and at 20 months after surgery (relative risk 0.24; 95% CI 0.21-2.1).

CONCLUSION

Laminoplasty retains posterior ligament complex showed no impact on the spinal deformities compared with laminoplasty, but significantly improved the postoperative spinal activity, alleviated pain symptoms, and reduced hospital recovery time.

Measurement of Deformity at the Craniovertebral Junction: Correlation of Triangular Area and Myelopathy

OBJECTIVE

Diseases of the craniovertebral junction (CVJ) are commonly associated with deformity, malalignment, and subsequent myelopathy. The misaligned CVJ might cause compression of neuronal tissues and subsequently clinical symptoms. The triangular area (TA), measured by magnetic resonance imaging/images (MRI/s), is a novel measurement for quantification of the severity of compression to the brain stem. This study aimed to assess the normal and pathological values of TA by a comparison of patients with CVJ disease to age- and sex-matched controls. Moreover, postoperative TAs were correlated with outcomes.

METHODS

Consecutive patients who underwent surgery for CVJ disease were included for comparison to an age- and sex-matched cohort of normal CVJ persons as controls. The demographics, perioperative information, and pre- and postoperative 2-year cervical MRIs were collected for analysis. Cervical TAs were measured and compared.

RESULTS

A total of 201 patients, all of whom had pre- or postoperative MRI, were analyzed. The TA of the CVJ deformity group was larger than the healthy control group (1.62 ± 0.57 cm2 vs. 1.01 ± 0.18 cm2, p < 0.001). Moreover, patients who had combined anterior odontoidectomy and posterior laminectomy with fixation had the greatest reduction in the TA (1.18 ± 0.58 cm2).

CONCLUSION

In CVJ deformity, the measurement of the cervical TA could indicate the severity of brain stem compression. After surgery, the TA had a varying degree of improvement, which could represent the efficacy of surgery.

Ideal entry point and trajectory for C2 pedicle screw placement in basilar invagination patients with high-riding vertebral artery based on 3D computed tomography

BACKGROUND

C2 pedicle screw placement in patients with basilar invagination (BI) is fraught with risks because of a high incidence of anatomical variations and high-riding vertebral artery (HRVA). However, no study can be found in the literature that attempted to identify the ideal entry point and trajectory through the C2 pedicle in BI patients with HRVA.

PURPOSE

To investigate the parameters of ideal entry point and trajectory for C2 pedicle screw placement in BI patients with HRVA and compare them with those in BI patients without HRVA and patients without BI as control. These parameters would serve as a guide to pedicle screw placement.

STUDY DESIGN

A retrospective comparative study.

PATIENT SAMPLE

A total of 396 patients (198 consecutive BI patients and 198 matched patients without BI as control) and 792 unilateral pedicles from April 2017 to October 2021 at two medical centers were included.

OUTCOME MEASURES

The insertion parameters of mediolateral angle, surface distance, cephalad angle, and vertical distance from the superior border of the lamina were the primary outcome measures for the reference of C2 pedicle screw placement. Furthermore, factors that affect the primary insertion parameters were assessed via multiple linear regression analyses.

METHOD

According to the diagnosis of BI and HRVA, the unilateral pedicles were assigned into HRVA of BI, non-HRVA of BI, HRVA of control, and non-HRVA of control groups. Subgroup analyses based on Goel types A and B were also performed. Moreover, vertebral artery (VA) anomalies that might result in potentially serious complications were identified and systematically compared.

RESULTS

The measurements of insertion parameters in BI patients with HRVA indicated a mean mediolateral angle of 27.42°, a mean cephalad angle of 43.02°, a mean surface distance of 9.74 mm, and a mean vertical distance from the superior border of the lamina of 3.85 mm. Compared with that in BI patients without HRVA, the measurements suggested that the entry point in BI patients with HRVA should be shifted upward by 0.38 mm and the trajectory should be angled cephalad by 6.05° and medially by 4.78°. In the control group, changes in the insertion parameters between HRVA and non-HRVA showed a similar trend to the BI group. Multiple linear regression showed that mediolateral angle was significantly associated with the male gender (B=-0.930, p=.017) and the diagnoses of HRVA (B=6.964, p<.001), Goel type A (B=-1.656, p=.003), and Goel type B (B=0.981, p=.030). Moreover, cephalad angle was significantly associated with the length of lateral mass (B=-0.319, p=.001) and the diagnoses of HRVA (B=3.254, p<.001) and Goel type A (B=6.924, p<.001). The VA anomalies were significantly higher in the BI group than in the control group.

CONCLUSIONS

The insertion parameters of the ideal entry point and trajectory for C2 screw placement in BI patients with HRVA were remarkably different from those of non-HRVA of BI, HRVA of control, and non-HRVA of control cohorts. Preoperative 3D computed tomography (CT) and CT angiography are highly recommended in such patients to improve intraoperative safety and reduce postoperative complications.

Posterior Surgery in the Treatment of Craniovertebral Junction Deformity with Torticollis

OBJECTIVE

To investigate the clinical effect of posterior surgery in the treatment of craniovertebral junction (CVJ) deformities with torticollis and methods for preventing and treating complications in order to obtain a reasonable treatment strategy.

METHODS

From January 2007 to December 2017, 78 patients who suffered from CVJ deformities with torticollis treated by posterior surgery were analyzed. The surgical techniques were all posterior correction and fusion to restore the anatomical alignment of the craniovertebral junction. The visual analog score (VAS) and Short Form-36 (SF-36) health survey questionnaire were utilized to evaluate preoperative and postoperative neck pain, and changes in the torticollis angle and atlas-dens interval (ADI) were evaluated through anteroposterior X-ray and computed tomography. Intra- and postoperative complications were all recorded. One-way ANOVA, LSD-t test, and χ² test were performed to evaluate the difference between the preoperative and postoperative data.

RESULTS

The mean follow-up time was 37.4 ± 15.7 months, the average operation time was 115.6 ± 12.8 min, and the average blood loss was 170.8 ± 26.3 mL. According to the deformity site, the range of posterior correction and fusion was as follows: 38 cases of C₁ -C₂ , 33 cases of C₀ -C₂ , and seven cases of C₀ -C₃ . The preoperative SF-36, VAS, torticollis angle, and ADI were 42.6 ± 8.8, 4.8 ± 1.1, 37.2 ± 11.2°, and 4.9 ± 2.3 mm, respectively. The difference was significant at 3 months post operation (p < 0.05), and there was no significant difference at the final follow-up compared with 3 months post operation (p > 0.05).

CONCLUSION

It can objectively achieve favorable correction and satisfactory clinical effects under posterior correction and fixation for CVJ deformities with torticollis. Intra- and postoperative complications can be settled by proper management.

The endoscopic transnasal approach to the lesions of the craniocervical junction: two case reports

The endoscopic endonasal approach (EEA) to the craniovertebral junction (CVJ) has recently been considered a safer alternative and less invasive approach than the traditional transoral approach because the complications associated with the latter are avoided or minimized. Here, we present two challenging cases of CVJ pathologies. The first case involved os odontoideum associated with anterior displacement of the occipitocervical junction where the EEA was used, followed by C0-C1-C2 fusion using a posterior approach to decompress the CVJ, and was complicated by rhinorrhea and Candida albicans meningitis. The second case involved basilar invagination with syringomyelia previously treated using a posterior approach, where aggravation of neuropathic symptoms required combined treatment with EEA and occipitocervical fusion of C0-C2-C3-C4, with the postoperative course challenged by operative site infection requiring drainage with debridement and antibiotic therapy. The EEA is an alternative approach for accessing the CVJ in well-selected patients. Knowledge of EEA complications is crucial for the optimal care of patients.

Vision-based pose estimation of craniocervical region: experimental setup and saw bone-based study

This article discusses the intervertebral motion present in the craniovertebral junction (CVJ) region. The CVJ region is bounded by the first three vertebras from the spinal column. It helps in bringing most of the neck motion. Intervention in this region requires surgery in which an implant is placed to stabilize the whole system. The various available implants need to undergo performance evaluation as their performance varies from region and anatomical diversity. For the Indian population, we are targeting to evaluate the performance of such an implant, testing it into a cadaver. The region of interest will be loaded as per the loading condition of an average human. Motion in these regions is evaluated using the camera. A preliminary test was done on a saw bone model of CVJ to assess the performance of segmentation methods. Multiple such ArUco markers are used to increase pose accuracy further, and the pose of the entire board of multiple tags provides us with reliable pose estimation. The absolute error ranged from a minimum of 0.1 mm to a maximum of 16 mm. At the same time, the mean and median absolute errors were 3.8961 mm and 3.35 mm. By considering the absolute lengths, the percentage error showed the following trends. The percentage error was between 3.9168% and 0.0230%.