Management of post-traumatic craniovertebral junction dislocation: A PRISMA-compliant systematic review and meta-analysis of casereports

Innovative C-Arm-Free Navigation Technique for Posterior Spinal Fixation for Atlantoaxial Subluxation: A Technical Note

Study design: Technical note. Objectives: To present a novel C-arm-free technique guided by navigation to insert and place a C1 lateral mass screw. Background and Objectives: Atlantoaxial subluxation (AAS) is a relatively common sequelae in patients with rheumatoid arthritis (RA) and upper cervical trauma. If they present with severe symptoms, surgical intervention such as posterior fusion is indicated. The established treatment for AAS is fixation with a C1 lateral mass screw and C2 pedicle screw (modified Goel technique) to achieve bony fusion. However, this technique requires fluoroscopy for C1 screw insertion. To avoid exposing the operating team to radiation, we present here a novel C-arm-free C1 lateral mass screw insertion technique for AAS. Materials and Methods: A 67-year-old man was referred to our hospital with neck pain, quadriparesis, and clumsiness and numbness of both upper and lower limbs. He had undergone C3-6 posterior fusion previously in another hospital. In physical examination, he had severe muscle weakness of bilateral upper limbs and hypoesthesia of all four limbs. He had hyper-reflexia of bilateral lower limbs and pollakiuria. His Japanese orthopedic score was 8 points out of 17. Preoperative radiograms showed AAS with an atlantodental interval (ADI) of 7 mm. MRI indicated retro-odontoid pseudotumor and severe spinal cord compression at the C1-2 level. The patient underwent posterior atlantoaxial fixation under navigation guidance. To prevent epidural bleeding during the insertion and placement of a C1 lateral mass screw, we have here defined a novel screw insertion technique. Results: The surgical time was clocked as 127 min and blood loss was 100 mL. There were no complications per-operatively or in the postoperative period. The patient showed almost full recovery (JOA 16/17) at two months follow-up and a solid bony fusion was noticed in the radiograms at one year follow-up. Conclusions: This novel surgical procedure and C1 lateral mas screw placement technique is a practical and safe method in recent advances of AAS treatment. Procedurally, the technique helps prevent epidural bleeding from the screw entry point and also allows for proper C1 screw insertion under navigation guidance without exposing surgeons and staff to the risk of fluoroscopic radiation.

An anatomical and radiological study of the tectorial membrane and its clinical implications

The radiological image of an intact tectorial membrane (TM) became an important favorable prognostic factor for craniovertebral instability. This study visualized the fascial layers of the TM and adjacent connective tissues with clinical significance by micro-CT and histological analysis. The TM firmly attached to the bony surface of the clivus, traversed the atlantoaxial joint posteriorly, and was inserted to the body of the axis showing wide distribution on the craniovertebral junction. The supradental space between the clivus, dens of the axis, anterior atlantooccipital membrane, and the TM contained profound venous networks within the adipose tissues. At the body of the axis, the compact TM layer is gradually divided into multiple layers and the deeper TM layers reached the axis while the superficial layer continued to the posterior longitudinal ligament of the lower vertebrae. The consistent presence of the fat pad and venous plexus in the supradental space and firm stabilization of the TM on the craniovertebral junction was demonstrated by high-resolution radiologic images and histological analysis. The evaluation of the TM integrity is a promising diagnostic factor for traumatic craniovertebral dislocation.

Upper cervical spine instability systematic review: a bibliometric analysis of the 100 most influential publications

BACKGROUND

Instability in the upper cervical spine, although rare, can be devastating. This spectrum of conditions includes occipitocervical instability, atlantoaxial instability and atlantoaxial rotatory displacement. Knowledge of the literature can provide better understanding of disease processes and management, and aid in clinical decision making. The objective of this study was to perform a bibliometric analysis to formulate a comprehensive review of the most cited publications.

METHODS

A systematic search of the literature was conducted using the Clarivate Web of Science database. The search query was '"Atlanto-occipital dislocation" OR "atlanto-occipital dissociation" OR "atlantoaxial rotatory displacement" OR "atlantoaxial instability"'. The top 100 articles based on frequency of citation were included in our study. Data extracted from articles included frequency of citation, year of publication, country of origin, journal of publication, level of evidence and article type.

RESULTS

Our initial search yielded 257 results that met the criteria. Articles not pertaining to atlanto-occipital instability were removed. Citation frequency ranged from 15 to 195. The most cited article was "Traumatic Anterior Atlanto-Occipital Dislocation" published by Powers et al. in 1979. The most productive decade was 2000-2009 with 45 publications. All decades showed a progressive increase in the number of papers published except for 2010-2019. Overall, 19 countries contributed and the most productive was the United States (n=61). The articles found in our search were cited a total of 4,095 times (3,463 without self-citations) averaging 40.95 citations per publication.

DISCUSSION

The goal of a bibliometric study is to assess trends in a specific field of study, provide evidence for the impact of an individual or field of study's research, and highlight potential areas for future research. While the number of citations does not necessarily reflect publication quality, it reflects overall influence based on recognition by peers in the field. Publications from the last 20 years have emphasized the use of newer technologies such as computed tomography (CT) and magnetic resonance imaging (MRI) to aid in diagnosis. Our study highlights the lack of high-level evidence articles and underscores that our understanding of these conditions in both pediatric and adult patients is maturing.

Atlanto-occipital dislocation in a child: a challenging diagnosis. Illustrative case

BACKGROUND

Atlanto-occipital dislocation (AOD) is a highly unstable injury of the osseoligamentous complex at the craniocervical junction that is more common in children. Its diagnosis remains a challenging process that must integrate clinical presentation and radiological criteria.

OBSERVATIONS

A 9-year-old child presented with severe craniocervical trauma (Glasgow Coma Scale score 6) and cardiorespiratory arrest on-site. Prompt resuscitation on-site and transfer to the university hospital were performed, and a computed tomography (CT) scan showed a subarachnoid hemorrhage around the brainstem and a retroclival hematoma. Most of the radiological criteria on CT scans for AOD were negative, except for the occipital condyle–C1 interval, and further imaging with magnetic resonance imaging permitted the diagnosis of AOD with rupture of both the tectorial membrane and the transverse ligament. Occipital-cervical Oc-C1–2 fixation was performed. The neurological outcome was excellent, with full recovery 6 months after the trauma.

LESSONS

AOD should be suspected in all high-intensity trauma in children, especially if the clinical presentation includes cardiorespiratory arrest and other brainstem and/or upper cervical cord symptoms along with premedullary subarachnoid hemorrhage. Understanding the ligamentous nature of the injury resulting in “normal” radiographs or CT scans is important to avoid underdiagnosing AOD, which can have detrimental consequences.

Fluoroscopy-Assisted C1-C2 Posterior Fixation for Atlantoaxial Instability: A Single-Center Case Series of 78 Patients

Background and Objectives: Posterior C1-C2 fixation, with trans-articular screws (TAS) or screw-rod-construct (SRC), is the main surgical technique for atlantoaxial instability, and can be performed with a fluoroscopy-assisted free-handed technique or 3D navigation. This study aimed to evaluate complications, radiological and functional outcome in patients treated with a fluoroscopy-assisted technique. Materials and Methods: A single-center consecutive cohort study was conducted of all adult patients who underwent posterior C1-C2 fixation, using TAS or CRS, between 2005-2019. Results: Seventy-eight patients were included, with a median follow-up time of 6.8 years. Trauma was the most common injury mechanism (64%), and cervicalgia the predominant preoperative symptom (88%). TAS was used in 33%, and SRC in 67% of cases. Surgery was associated with a significant reduction in cervicalgia (from 88% to 26%, p < 0.001). The most common complications were vertebral artery injury (n = 2, 2.6%), and screw malposition (n = 5, 6.7%, of which 2 were TAS and 3 were SRC). No patients deteriorated in their functional status following surgery. Conclusions: Fluoroscopy-assisted C1-C2 fixation with TAS or SRC is a safe and effective treatment for atlantoaxial instability, with a low complication rate, few surgical revisions, and pain relief in the majority of the cases.

EuroQol-5 dimensions health-related quality of life questionnaire in craniovertebral instability treated with posterior fixation with or without occipital plating: A comparative study with matched datasets

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Prevalence of high-riding vertebral arteries and narrow C2 pedicles among Central-European population: a computed tomography-based study

High-riding vertebral artery (HRVA) and narrow C2 pedicles (C2P) pose a great risk of injuring the vessel during C2 pedicle or transarticular screw placement. Recent meta-analysis revealed a paucity of European studies regarding measurements and prevalence of these anatomical variants. Three hundred eighty-three consecutive cervical spine CT scans with 766 potential screw insertion sites were analyzed independently by two trained observers. C2 internal height (C2InH), C2 isthmus height (C2IsH), and C2P width were measured. Kappa statistics for inter- and intraobserver reliability as well as for inter-software agreement were calculated. HRVA was defined as C2IsH of ≤ 5 mm and/or C2InH of ≤ 2 mm. Narrow C2P was defined as C2P width ≤ 4 mm. STROBE checklist was followed. At least 1 HRVA was found in 25,3% (95% CI 21,1–29,8) of patients (16,7% of potential sites). At least 1 narrow C2P was seen in 36,8% (95% CI 32,1–41,7) of patients (23,8% of potential sites). Among those with HRVA, unilateral HRVA was present in 68,0% (95% CI 58,4–77,0), whereas bilateral HRVA in 32,0% (95% CI 23,0–41,6). No difference in terms of laterality (right or left) was seen neither for HRVA nor narrow C2P. Significant differences were found between females and males for all measurements. Each parameter showed either good or excellent inter- or intraobserver, and inter-software agreement coefficients. HRVA and narrow C2P are common findings in Central-European population and should be appreciated at the planning stage before craniocervical instrumentation. Measurements can be consistently reproduced by various observers at varying intervals using different software.

Risk of the high-riding variant of vertebral arteries at C2 is increased over twofold in rheumatoid arthritis: a meta-analysis

Rheumatoid arthritis (RA) might lead to atlantoaxial instability requiring transpedicular or transarticular fusion. High-riding vertebral artery (HRVA) puts patients at risk of injuring the vessel. RA is hypothesized to increase a risk of HRVA. However, to date, no relative risk (RR) has been calculated in order to quantitatively determine a true impact of RA as its risk factor. To the best of our knowledge, this is the first attempt to do so. All major databases were scanned for cohort studies combining words "rheumatoid arthritis" and "high-riding vertebral artery" or synonyms. RA patients were qualified into the exposed group (group A), whereas non-RA subjects into the unexposed group (group B). Risk of bias was explored by means of Newcastle-Ottawa Scale. MOOSE checklist was followed to ensure correct structure. Fixed-effects model (inverse variance) was employed. Four studies with a total of 308 subjects were included in meta-analysis. One hundred twenty-five subjects were in group A; 183 subjects were in group B. Mean age in group A was 62,1 years, whereas in group B 59,9 years. The highest risk of bias regarded "comparability" domain, whereas the lowest pertained to "selection" domain. The mean relative risk of HRVA in group A (RA) as compared with group B (non-RA) was as follows: RR = 2,11 (95% CI 1,47-3,05), I² = 15,19%, Cochrane Q = 3,54 with overall estimate significance of p < 0,001. Rheumatoid arthritis is associated with over twofold risk of developing HRVA, and therefore, vertebral arteries should be meticulously examined preoperatively before performing craniocervical fusion in every RA patient.