Complex Craniovertebral Junction Research Articles

An institutional study on accuracy of freehand cervical C1 C2 screws placement by knock and drill technique in craniovertebral anomalous bony anatomy: An evaluation of more than 600 screws based on SGPGI screw accuracy criteria.

To assess the accuracy of freehand cervical C1 C2 screws placement by knock and drill (K and D) technique in craniovertebral anomalous bony anatomy. From January 2017 to December 2022, 682 consecutive C1 C2 screws in 215 patients with craniovertebral junction (CVJ) anomalies were enrolled. All patients underwent posterior fixation with K and D technique without any fluoroscopic guidance. The patient's demographic details, clinical details, radiological details, major intraoperative events, and postoperative complications were noted. The screws malposition grades and direction on CT images in the axial and sagittal plane were defined as new per proposed "SGPGI accuracy criteria." All patients had a clinical evaluation at 3-month follow-up. Total 682 C1, C2 screws were placed in 215 patients for CVJ anomalies using K and D technique. The accuracy of screws placement by freehand technique was 84.46% (576/682). So with technique explained the rate of malplacement in simple (16.35%) and complex (15.19%) groups were almost comparable and comparison difference was not significant (P = 0.7005). The freehand technique, as described, is effective in cases of anomalous bony anatomy, and it is mandatory in complex CVJ anomalies. The accuracy of screw placement and VA injury is comparable with major studies. This technique is supposedly cost-effective and less hazardous to both health-care workers and patients.

C2 Superior Facetal Osteotomy: A Novel Technique in Complex Craniovertebral Junction Surgery for C1 Lateral Mass Screw Placement.

Complex craniovertebral junction (CVJ) defects account for a considerable proportion of CVJ diseases. Given the heavily assimilated C1, an unfavorable C1-C2 joint orientation, an overriding C2 superior facet, a low-hanging occiput, and an abnormal vertebral artery course with a high-riding vertebral artery, placement of C1 lateral mass screws might be difficult. To address this, a novel technique for placing C1 lateral mass screws that avoid vertebral artery injury, low-hanging occiput, and overriding C2 superior facet was developed in this study. This approach enables firm fixation of C1-C2 even in difficult situations where the placement of the C1 lateral mass is challenging.

Cross-Cultural Teachings from Cremation Practices: Atmaram for the Departed, Shiva Linga for the Living, and Odontoid Fracture for the Neurosurgeons!

Atmaram bone (C2 axis vertebra) is usually handed over to the family of the deceased on the next day after cremation during the ''Asthi sanchaya '' commemoration. ''Asthi visarajan'' involves the practice of immersing the bones and ashes of the deceased in the Holy Ganges river as per Hindu beliefs. Atmaram bone, which usually does not burn during cremation, is handed over to the family of the departed (asthi sanchaya) after cremation which is then immersed in the holy Ganges river ( asthi visarajan). Atma means soul, Ram means Lord and Atmaram combined means the one who is Lord of his own soul." Worshiping of Lord Shiva (while living) and Asthi sanchaya-Asthi visarajan (of the departed) are two religious venerations in Hinduism. Atmaram bone was handed over to me for immersion in the holy Ganges on November 6, 2020, after conducting the asthi sanchaya of my mother during the coronavirus disease 2019 (COVID-19) pandemic. Atmaram bone looked like a Shivalinga statue to most who looked at it, whereas it resembled the image of the axis vertebrae (C2 vertebra) to me when I saw it that sacred day. Atmaram bone, the Shivalinga, and the C2 axis vertebra are among the most precious and sacred objects that humans can handle as relatives, as devotees, and as neurosurgeons, respectively. Asclepius, possibly a skilled war surgeon/neurosurgeon, was worshipped at Asclepieia. Trephination surgery in neurosurgery and religion are intertwined historically. Though there is no published literature, neurosurgeons in various parts of the world do offer religious prayers prior to major neurosurgical operations. In line with the religious veneration of worshipping Shiva Ling or immersion of bones of the departed soul in the Holy Ganges river, we believe it is the sacred responsibility of the operating neurosurgeon to perform surgery in complex craniovertebral junction. As neurosurgeons, we cannot ignore the axis in the living, the odontoid fracture in the injured, and the Atmaram in the deceased.

C1-C2 coronal and sagittal joint angle based treatment algorithm for the need of transoral odointectomy in complex craniovertebral junction anomalies with Clinico-Radiological outcome analysis

Objective Craniovertebral junction (CVJ) pathology by virtue of its complexity is a surgical challenge in the realm of neurosurgery. We analyzed the need for transoral odointectomy in view of their C1-C2 joint coronal and sagittal angle of 58 patients with complex CVJ anomalies treated surgically. The clinical and radiological outcome of the patients was assessed and a treatment algorithm is proposed. Methods A total of 58 cases were included in the Prospective study over the period of 2 years. Patients were evaluated clinically, investigated, and operated with reduction and rigid internal fixation with screws and rod. The clinical outcome was measured by Modified Japanese orthopedic association score(mJOA) and radiologically by conventional craniometrics indices. Paired ‘t’ test used for statistical analysis. Results Mean age of patients: 30 years, with mean, follow up: 20.5 months. 46(80%) patients were operated by posterior and 12(20%) by combined approach (anterior transoral with posterior). Occipitocervial fixation was done in 15(25.8%) cases and C1-C2 fixation in 43(74.2%) cases. As compared to patients with low coronal angle, the patient with coronal angle >65° needed anterior decompression (87.5%) and all (100%) had Occipitocervical fixation. Clinical outcome analysis showed significant improvement in mean mJOA score (preop 11.9 Vs postop 14.6) after surgery. All craniometrics indices were significantly improved after surgery. The overall complication rate was 10% with a mortality of 1.7%. 6 months follow up completed in all patients with a 100% fusion rate. Conclusion Occipitocervical fixation and anterior decompression is required in increased C1-C2 joint CA (>65°) for bony realignment and adequate decompression. Measurement of C1-C2 joint coronal and sagittal angle in complex CVJ anomalies will easily anticipate the surgeon regarding the need for anterior decompression inform of transoral odointectomy.

Arterial Fencing: A Challenge During Complex Craniovertebral Junction Surgery

A 32-year-old woman presented with chronically progressive spastic quadriparesis. Detailed clinicoradiological evaluation led to the diagnosis of irreducible atlantoaxial dislocation and basilar invagination, with associated "kissing" carotids and an anomalous right vertebral artery (VA). Both internal carotid arteries had an abnormally tortuous course, "kissing" retropharyngeally at the level of C1-C2. The right VA became intradural at the level of C2-C3, an extremely rare anomaly-C3 segmental artery. Despite the deformed joints and the possibility of injuring the anomalous right VA during C2-C3 instrumentation, a tailored posterior-only approach was used to circumvent the arterial fence created by both vascular anomalies. The patient underwent bilateral C1-C2 joint opening and left C1-C2 joint spacer placement, followed by bilateral occipito-C3-C4 fixation. This is possibly the first reported case of a complex craniovertebral junction anomaly associated with both kissing carotids and a C3 segmental VA.

C1 lateral mass reduction screws for treating atlantoaxial dislocations: Bringing ease by modification.

ABSTRACTObjective:The C1-C2 fixation technique revolutionized the management of complex craniovertebral junction (CVJ) anomalies. Presently used polyaxial screw and rod systems have inadvertent technical difficulties in rod fitting and reduction of atlantoaxial dislocations (AAD) requiring forceful joint handling. The purpose of this study is to analyze the use of a specially designed “reduction screw” in C1 lateral mass in C1-C2 fixation for treating AAD with or without basilar invagination (BI).Study Design:This is a retrospective cohort study in which long lateral mass reduction screws were used for C1-C2 fixation.Materials and Methods:Eighteen patients diagnosed with congenital AAD with or without BI treated with C1-C2 fixations using C1 reduction lateral mass were included in the study. The outcome was measured clinically by the modified Japanese Orthopedic Association score and radiologically by conventional craniometric indices.Results:Among all cases included in the study, 72% (13/18) are males and 18% (5/18) are females with average age at presentation of 33.5 years. Among 18 cases of AAD, 84% (15/18) of patients have BI, 22% (4/18) have Chiari Type 1 malformation, and one patient has Klipple–Feil syndrome. Symptomatic improvement is noted in all patients following surgery. Adequate reduction of AAD with normalization of radiological indices was also achieved in all 18 (100%) patients.Conclusion:C1 lateral mass reduction screw in C1-C2 fixation helps in reduction of AAD and BI (Type A) even in difficult cases of CVJ anomalies with intraoperative technical ease, reduced operative time, no need for special instruments or complex maneuvers, and avoiding potential neurological injury.

Occipital-Cervical Fusion and Ventral Decompression in the Surgical Management of Chiari-1 Malformation and Syringomyelia: Analysis of Data From the Park-Reeves Syringomyelia Research Consortium.

Occipital-cervical fusion (OCF) and ventral decompression (VD) may be used in the treatment of pediatric Chiari-1 malformation (CM-1) with syringomyelia (SM) as adjuncts to posterior fossa decompression (PFD) for complex craniovertebral junction pathology. To examine factors influencing the use of OCF and OCF/VD in a multicenter cohort of pediatric CM-1 and SM subjects treated with PFD. The Park-Reeves Syringomyelia Research Consortium registry was used to examine 637 subjects with cerebellar tonsillar ectopia≥5mm, syrinx diameter≥3mm, and at least 1 yr of follow-up after their index PFD. Comparisons were made between subjects who received PFD alone and those with PFD+OCF or PFD+OCF/VD. All 637 patients underwent PFD, 505 (79.2%) with and 132 (20.8%) without duraplasty. A total of 12 subjects went on to have OCF at some point in their management (PFD+OCF), whereas 4 had OCF and VD (PFD+OCF/VD). Of those with complete data, a history of platybasia (3/10, P=.011), Klippel-Feil (2/10, P=.015), and basilar invagination (3/12, P<.001) were increased within the OCF group, whereas only basilar invagination (1/4, P<.001) was increased in the OCF/VD group. Clivo-axial angle (CXA) was significantly lower for both OCF (128.8± 15.3°, P=.008) and OCF/VD (115.0± 11.6°, P=.025) groups when compared to PFD-only group (145.3± 12.7°). pB-C2 did not differ among groups. Although PFD alone is adequate for treating the vast majority of CM-1/SM patients, OCF or OCF/VD may be occasionally utilized. Cranial base and spine pathologies and CXA may provide insight into the need for OCF and/or OCF/VD.

Letter to the Editor Regarding: “Usefulness of 3D Printed Models in the Management of Complex Craniovertebral Junction Anomalies: Choice of Treatment Strategy, Design of Screw Trajectory, and Protection of Vertebral Artery.”

Letter to the Editor Regarding: “Usefulness of 3D Printed Models in the Management of Complex Craniovertebral Junction Anomalies: Choice of Treatment Strategy, Design of Screw Trajectory, and Protection of Vertebral Artery.”

Reconsideration of the transoral odontoidectomy in complex craniovertebral junction patients with irreducible anterior compression

BackgroundAlthough the single-stage posterior realignment craniovertebral junction (CVJ) surgery could treat most of the basilar invagination (BI) and atlantoaxial dislocation (AAD), there are still some cases with incomplete decompression of the spinal cord, which remains a technique challenging situation.MethodsEleven patients were included with remained myelopathic symptoms after posterior correction due to incomplete decompression of the spinal cord. Transoral odontoidectomy assisted by image-guided navigation and intraoperative CT was performed. Clinical assessment and image measurements were performed preoperatively and at the most recent follow-up.ResultsEleven patients were followed up for an average of 47 months. Symptoms were alleviated in 10 of 11 patients (90.9%). One patient died of an unknown reason 1 week after the transoral approach. The clinical and radiological parameters pre- and postoperatively were reported.ConclusionTransoral odontoidectomy as a salvage surgery is safe and effective for properly selected BI and AAD patients after inadequate indirect decompression from posterior distraction and fixation. Image-guided navigation and intraoperative CT can provide precise information and accurate localization during operation, thus enabling complete resection of the odontoid process and decompression of the spinal cord.

Axis Metastasis, Atlantoaxial Dislocation and Cervical Syringomyelia: A Case Report

Syringomyelia associated with atlantoaxial dislocation is usually described in patients with complex craniovertebral junction anomaly. However, atlantoaxial dislocation without craniovertebral junction bony anomaly very rarely causes syringomyelia. In this report, we describe a case of syringomyelia associated with atlantoaxial dislocation secondary to metastatic tumour of the axis vertebra.

Usefulness of 3D Printed Models in the Management of Complex Craniovertebral Junction Anomalies: Choice of Treatment Strategy, Design of Screw Trajectory, and Protection of Vertebral Artery

To evaluate the usefulness of 3-dimensional (3D) printed models as an aid for the treatment of complex CVJ anomalies. 3D printed models were fabricated for 21 patients with complex CVJ anomalies, including vertebral artery anomaly, thin C2 pedicle, vertical atlantoaxial facet joint, or rotational dislocation combined with atlantoaxial dislocation and basilar invagination. Preoperative planning, surgical simulation, and intraoperative reference were achieved using the 3D model during the surgical treatment. The usefulness of 3D printed models, and postoperative clinical and radiological outcomes were assessed. Direct posterior reduction and atlantoaxial fixation were achieved in 19 patients. Transoral odontoidectomy followed by posterior fixation was implemented for 2 patients with vertical facet joint and rotational dislocation. All screws were safely inserted with no complication, and 90% patients achieved a >60% reduction of both horizontal and vertical dislocation. Clinical symptoms improved in all patients, with the averaged Japanese Orthopedic Association scores increasing from 11.14 to 14.43 (P < 0.01). The patient-specific 3D printed model would be an effective tool for evaluation of the reducibility of the atlantoaxial dislocation and basilar invagination, decision making in choosing the optimal surgical approach and way of fixation, and precise placement of the screw while protecting the vertebral artery and spinal cord. The risk of neurovascular injury was minimized, and encouraging outcomes were achieved with the aid of this technique.

A Dual Approach for the Management of Complex Craniovertebral Junction Abnormalities: Endoscopic Endonasal Odontoidectomy and Posterior Decompression with Fusion

BackgroundVentral brainstem compression secondary to complex craniovertebral junction abnormality is an infrequent cause of neurologic deterioration in pediatric patients. However, in cases of symptomatic, irreducible ventral compression, 360° decompression of the brainstem supported by posterior stabilization may provide the best opportunity for improvement in symptoms. More recently, the endoscopic endonasal corridor has been proposed as an alternative method of odontoidectomy associated with less morbidity. We report the largest single case series of pediatric patients using this dual-intervention surgical technique. The purpose of this study was to evaluate the surgical outcomes of pediatric patients who underwent posterior occipitocervical decompression and instrumentation followed by endoscopic endonasal odontoidectomy performed to relieve neurologic impingement involving the ventral brainstem and craniocervical junction.MethodsBetween January 2011 and February 2017, 7 patients underwent posterior instrumented fusion followed by endonasal endoscopic odontoidectomy at our unit. Standardized clinical and radiological parameters were assessed before and after surgery. A univariate analysis was performed to assess clinical and radiologic improvement after surgery.ResultsA total of 14 operations were performed on 7 pediatric patients. One patient had Ehlers-Danlos syndrome, 1 patient had a Chiari 1 malformation, and the remaining 5 patients had Chiari 1.5 malformations. Average extubation day was postoperative day 0.9. Average day of initiation of postoperative feeds was postoperative day 1.0.ConclusionsThe combined endoscopic endonasal odontoidectomy and posterior decompression and fusion for complex craniovertebral compression is a safe and effective procedure that appears to be well tolerated in the pediatric population.

"Fusing the appropriate" in complex craniovertebral junction anomalies.

"Fusing the appropriate" in complex craniovertebral junction anomalies.

Knock and Drill Technique: A Simple Tips for the Instrumentation in Complex Craniovertebral Junction Anomalies without using Fluoroscopy.

Context:Existence of complex variable bony and vertebral artery (VA) anomalies at craniovertebral junction (CVJ) in subset of complex CVJ anomalies demands individualized instrumentation policy and placing screws in each bone requires strategic preoperative planning and intraoperative skills.Aim:To evaluate the clinical accuracy of knock and drill (K and D) technique for the screw placement in complex CVJ anomalies.Settings and Design:Prospective study and operative technical note.Materials and Methods:Totally 36 consecutive patients (16 - pediatrics, 20 - adult patients) of complex CVJ: Complete/partial occipitalized C1 vertebra; at least one hypoplastic (C1/C2) articular mass, rotational component, and variations in the third part of VA were included in this study. Preoperative detail computed tomography (CT) CT CVJ with three-dimensional reconstruction was done for the assessment of CVJ anatomy and facet joint orientation. The accuracy of novel technique was assessed with postoperative CT to evaluate cortical breach in between 5th and 7th postoperative day in all the patients. All patients were underwent clinico-radiological evaluation at 6-month follow-up.Results:Totally 144 screws were placed using K and D technique (pediatric group - 64 screws, adult patients - 80 screws). Total of 12 screws were placed in C1 lateral mass in both age group without any bony cortical breach and complication. Sixteen C2 pedicle screws and 12 C2 pars screw in pediatrics and 18 C2 pedicle screws in adult patients were placed without any bony breach or VA injury. Out of thirty subaxial lateral mass screws in pediatric group, the bony breach was encountered with one screw (3.3%). Total of 38 C2 pars screws was placed in adult group in which bony breach along with VA injury was encounter with 1screw (2.6%).Conclusion:A simple technique of K and D for placing a screw increases the accuracy and spectrum of bony purchase and has the potential to reduce the complication in patients with complex CVJ anomalies.

Understanding the Course of Vertebral Artery at Craniovertebral Junction in Occipital Assimilation of Atlas: Made Simplified Using Conventional Angiography.

Introduction Preoperative assessment of vertebral artery (VA) is important to avoid its injury during surgery at craniovertebral junction (CVJ). The main concern is the course of third segment of VA (V3) while performing instrumentation at CVJ, that is, segment of VA from its course through transverse foramen of C2 to its course along the posterior arch of C1. This segment of VA includes its passage through C1 transverse foramen as well. This observational study was done to analyze the course, curvature, and termination of VA in patients with occipital assimilation of atlas at CVJ, a complex congenital anomaly, and compared with the normal course for better understanding especially by young neurosurgeons and spine surgeons. Materials and Method This is an observational study that included patients with occipitalized C1 with or without associated anomalies. Out of 30 patients of CVJ anomalies, 16 patients had occipitalized atlas. Digital subtraction angiography was done in all cases. It was done by selectively catheterizing the VA using standard Seldinger's technique and both anteroposterior and lateral projections were taken. Results The course of VA was not identical on either side in any individual. It was lengthened and tortuous in all patients. Different types of anomalous course were encountered like bypassing transverse foramen of C1, close relation with C1-2 facet joints, variable course along the posterior arch of C1, abnormal termination and fenestration of VA. Conclusion Craniovertebral junction anomalies are not only bony or neural, but are vascular too. Complex CVJ anomalies are associated with higher incidence of anomalous course of the VA, an important surgical consideration.

Three-dimensional models: an emerging investigational revolution for craniovertebral junction surgery.

Complex craniovertebral junctional anomalies can be daunting to treat surgically, and preoperative information regarding the osseous abnormalities, course of the vertebral arteries, size of the pedicles, and location of the transverse foramina is invaluable to surgeons operating on these challenging cases. The authors present their experience with the emerging technology of 3D model acquisition for surgery in 11 cases of complex craniovertebral junction region anomalies. For each case, a 3D printed model was made from thin CT scans using a 64-slice CT scanner. The inclination of the joints, the presence of false articulations, the size of the pedicles, and the course of the vertebral arteries were studied preoperatively on the 3D models. The sizes of the plates and screws to be used and the angle of insertion of the screws were calculated based on the data from the models. The model was scaled to actual size and was kept beside the operating surgeon in its anatomical position during surgery. The potential uses of the models and their advantages over conventional radiological investigations are discussed. The authors conclude that 3D models can be an invaluable aid during surgery for complex craniovertebral junction anomalies. The information available from a real life-size model supersedes the information available from 3D CT reconstructions and can also be superior to virtual simulation. The models are both cost effective and easy to build and the authors suggest that they may form the basis of investigations in the near future for craniovertebral junction surgery.

Endoscopic Transnasal Odontoidectomy With Anterior C1 Arch Preservation and Anterior Vertebral Column Reconstruction in Patients With Irreducible Bulbomedullary Compression by Complex Craniovertebral Junction Abnormalities: Operative Nuance.

During the past decades, the transoral transpharyngeal approach has been advocated as the standard route for the removal of odontoid causing an irreducible symptomatic neural compression. However, it may be potentially associated with a significant built-in morbidity because of the splitting of the soft palate for an adequate working angle, tracheostomy, and incision of the oral mucosa, causing exposure to a higher risk of infection by oral flora. To describe our experience with the minimally invasive pure endoscopic transnasal odontoidectomy in patients with bulbomedullary compression affected by complex anterior craniovertebral junction abnormalities. Five patients underwent a pure endoscopic neuronavigation-assisted transnasal odontoidectomy with anterior C1 arch preservation. Moreover, the anterior cervical spine column was reconstructed by filling the gap between the C1 arch and the residual C2 body with autologous/artificial bone. Neither tracheostomy nor enteral tube feeding were needed in any case. A postoperative neurological improvement was observed in all patients. Postoperative imaging confirmed a satisfactory spinal cord decompression with cervical anterior column arthrodesis, and without evidence of instability at follow-up, so far. The endoscopic transnasal approach seems to represent an efficient and safe alternative to the transoral route for the resection of odontoid process causing irreducible bulbomedullary compression. It provides a straightforward and minimally invasive natural surgical corridor to the anterior craniocervical junction, allowing a better working angle with preservation of spine biomechanics, while minimizing potential comorbidities.

Craniovertebral Junction Instability: A Review of Facts about Facets.

Craniovertebral junction surgery involves an appropriate philosophical, biomechanical and anatomical understanding apart from high degree of technical skill and ability of controlling venous and arterial bleeding. The author presents his 30-year experience with treating complex craniovertebral junction instability related surgical issues. The facets of atlas and axis form the primary site of movements at the craniovertebral junction. All craniovertebral junction instability is essentially localized to the atlantoaxial facet joint. Direct manipulation and fixation of the facets forms the basis of treatment for instability.

Intraoperative Computed Tomography With an Integrated Navigation System in Stabilization Surgery for Complex Craniovertebral Junction Malformation

This study was designed to report our preliminary experience with stabilization procedures for complex craniovertebral junction malformation (CVJM) using intraoperative computed tomography (iCT) with an integrated neuronavigation system (NNS). To evaluate the workflow, feasibility and clinical outcome of stabilization procedures using iCT image-guided navigation for complex CVJM. The stabilization procedures in CVJM are complex because of the area's intricate geometry and bony structures, its critical relationship to neurovascular structures and the intricate biomechanical issues involved. A sliding gantry 40-slice computed tomography scanner was installed in a preexisting operating room. The images were transferred directly from the scanner to the NNS using an automated registration system. On the basis of the analysis of intraoperative computed tomographic images, 23 cases (11 males, 12 females) with complicated CVJM underwent navigated stabilization procedures to allow more control over screw placement. The age of these patients were 19-52 years (mean: 33.5 y). We performed C1-C2 transarticular screw fixation in 6 patients to produce atlantoaxial arthrodesis with better reliability. Because of a high-riding transverse foramen on at least 1 side of the C2 vertebra and an anomalous vertebral artery position, 7 patients underwent C1 lateral mass and C2 pedicle screw fixation. Ten additional patients were treated with individualized occipitocervical fixation surgery from the hypoplasia of C1 or constraints due to C2 bone structure. In total, 108 screws were inserted into 23 patients using navigational assistance. The screws comprised 20 C1 lateral mass screws, 26 C2, 14 C3, or 4 C4 pedicle screws, 32 occipital screws, and 12 C1-C2 transarticular screws. There were no vascular or neural complications except for pedicle perforations that were detected in 2 (1.9%) patients and were corrected intraoperatively without any persistent nerves or vessel damage. The overall accuracy of the image guidance system was 98.1%. The duration of interruption during the surgical process for the iCT was 8±1.5 minutes. All patients were clinically evaluated using Nurick grade criteria and for neurological deficits 3 months after surgery. Twenty-one patients (91.3%) improved by at least 1 Nurick grade, whereas the grade remained unchanged in 2 (8.7%) patients. Craniovertebral stability and solid bone fusion was achieved in all patients. NNS was found to correlate well with the intraoperative findings, and the recalibration was uneventful in all cases and had an accuracy of 1.8 mm (range, 0.6-2.2 mm). iCT scanning with integrated NNS was found to be both feasible and beneficial in the stabilization procedures for complex CVJM. In this unusual patient population, the technique seemed to be of value for negotiating complex anatomy and for achieving more control over screw placement.

Individualized Treatment of Complex Craniovertebral Junction Abnormalities by Intraoperative Computed Tomography and Navigation System

Background: Treatment of complex craniovertebral junction abnormalities (CCJA) with ventral cervicomedullary compression is challenging due to the aberrant anatomic structures. The exact site of the compression is usually away from the midline. The intraoperative CT and navigation system is helpful for the localization. Objective: To assess the feasibility and potential utility of this system in individualized treatment of CCJA. Methods: We applied this technology to endoscopic transnasal or microsurgical transoral odontoidectomy and/or clivusectomy in 25 cases, odontoidectomy through posterior midline approach in 1 case, and transoral C1 lateral mass resection in 1 case. The pre- and postoperative neurologic status was examined. Results: No neurovascular injury occurred during surgery. Neuronavigation was found to correlate well with the intraoperative findings. All the patients had the improvement of the presenting clinical symptoms. The mean postoperative Japanese Orthopedic Association score was 14.9, compared with the preoperative score of 10.6 (p < 0.01). One case had postoperative pulmonary infection and one case with clivusectomy had the rupture of the dura mater and leakage of cerebrospinal fluid. Conclusions: For some complicated situations of the craniovertebral junction abnormalities, the treatment strategies should be tailored and individualized and the intraoperative CT-based navigation is an effective method to be considered.