"Letter to the editor: traumatic atlantoaxial rotatory fixation in adults: a systematic review of published cases".

This critique evaluates a recent study on adult traumatic atlantoaxial rotatory fixation (AARF), focusing on its strengths, weaknesses, and suggestions for future research. The study provides a comprehensive examination of the anatomical and biomechanical complexities of the C1-C2 articulation, shedding light on the rare nature of adult traumatic AARF and common injury mechanisms. It categorizes AARF based on the atlanto-dental interval (ADI) and dislocation severity, aiding clinicians in assessing injury severity and treatment planning. Furthermore, the study explores conservative and surgical management approaches, offering valuable insights into treatment decision-making and outcomes. However, limitations such as its retrospective nature, reliance on reported cases, lack of standardized protocols, and limited sample size may constrain the generalizability of findings. Future research should prioritize prospective, multicenter studies with standardized protocols, collaborative efforts among institutions, and innovative techniques to advance our understanding and management of adult traumatic AARF.

Traumatic atlantoaxial rotatory fixation in adults: a systematic review of published cases.

Atlantoaxial rotatory fixation (AARF) in adults is a rare and clinically challenging condition characterized by a spectrum of etiological factors, predominantly attributed to traumatic and inflammatory pathologies within the craniovertebral region. Trauma is the most frequently identified cause within the adult population, with the first case report published in 1907. This study aims to conduct a systematic review that addresses the clinical presentations and management strategies relating to traumatic atlantoaxial rotatory fixation in adults. A comprehensive search of the PubMed database was executed, adhering to the PRISMA guidelines. The inclusion criteria encompassed case reports and series documenting AARF cases in individuals aged 18 and above, spanning database inception to July 2022. Studies not published in the English language were excluded. A total of 61 articles reporting cases of AARF in the adult population were included in the study. The mean age of affected individuals was 36.1 years (± 15.6), with a distribution of 46% females and 54% males. Predominant mechanisms of injury included motor vehicle accidents and falls, constituting 38% and 22% of cases, respectively. Among the classification systems employed, Fielding and Hawkins type I accounted for the majority at 63%, followed by type II at 10%, and type III at 4%. Conservative management was used for treatment in 65% of acute (65%) cases and 29% of chronic cases. Traumatic AARF is a rare phenomenon in the adult population, is more common in younger adults, and does not often present with neurologic deficits. Patients diagnosed acutely are more likely to be successfully treated with conservative management, while patients diagnosed chronically are less likely to be reduced with conservatively and often require surgical treatment. Surgery should be considered for patients with irreducible dislocations, ligamentous injuries, unstable associated fractures, and persistent pain resistant to conservative management.

Comparison of iCT-based navigation and fluoroscopic-guidance for atlantoaxial screw placement in 78 patients with traumatic cervical spine injuries.

BACKGROUND CONTEXT: Studies have shown biomechanical superiority of cervical pedicle screw placement over other techniques. However, accurate placement is challenging due to the inherent risk of neurovascular complications. Navigation technology based on intraoperative 3D imaging allows highly accurate screw placement, yet studies specifically investigating screw placement in patients with traumatic atlantoaxial injuries are scarce. The aim of this study was to compare atlantoaxial screw placement as treatment of traumatic instabilities using iCT-based navigation or fluoroscopic-guidance with intraoperative 3D control scans. METHODS: This was a retrospective review of patients with traumatic atlantoaxial injuries treated operatively with dorsal stabilization of C1 and C2. Patients were either assigned to the intraoperative navigation or fluoroscopic-guidance group. Screw accuracy, procedure time, and revisions were compared. RESULTS: Seventy-eight patients were included in this study with 51 patients in the navigation group and 27 patients in the fluoroscopic-guidance group. In total, 312 screws were placed in C1 and C2. Screw accuracy was high in both groups; however, pedicle perforations > 1 mm occurred significantly more often in the fluoroscopic-guidance group (P = 0.02). Procedure time was on average 23 min shorter in the navigation group (P = 0.02). CONCLUSIONS: This study contributes to the available data showing that navigated atlantoaxial screw placement proves to be feasible as well as highly accurate compared to the fluoroscopic-guidance technique without prolonging the time needed for surgery. When comparing these data with other studies, the application of different classification systems for assessment of screw accuracy should be considered.

Augmented Reality in Spine Surgery: A Case Study of Atlantoaxial Instrumentation in Os Odontoideum.

Despite advancement in surgical innovation, C1-C2 fixation remains challenging due to risks of screw malposition and vertebral artery (VA) injuries. Traditional image-based navigation, while useful, often demands that surgeons frequently shift their attention to external monitors, potentially causing distractions. In this article, we introduce a microscope-based augmented reality (AR) navigation system that projects both anatomical information and real-time navigation images directly onto the surgical field. In the present case report, we discuss a 37-year-old female who suffered from os odontoideum with C1-C2 subluxation. Employing AR-assisted navigation, the patient underwent the successful posterior instrumentation of C1-C2. The integrated AR system offers direct visualization, potentially minimizing surgical distractions. In our opinion, as AR technology advances, its adoption in surgical practices and education is anticipated to expand.

[Grisel's syndrome : about two cases of a atlantoaxial (C1-C2) subluxation]. / Le syndrome de Grisel : à propos de deux cas de subluxation C1-C2.

Grisel's syndrome is a non-traumatic atlantoaxial (C1-C2) subluxation and one of the causes of torticollis in children. The subluxation occurs in the context of an infection in the ENT ("Ear Nose and Throat") region or following surgery. Diagnosis is based on clinical examination and radiological assessment. Treatment is typically medical and conservative, with surgical interventions reserved for recurrences and late presentations. We discuss here two cases of C1-C2 subluxation. The first case involves a 10-year-old child with subluxation following a rhinopharyngitis. This presentation is the classical manifestation of Grisel's syndrome. Prompt management led to correction of the subluxation using medical treatment and a soft Philadelphia collar. The second case involves a 34-year-old adult who developed posterior headaches after sphenoidotomy surgery. Grisel's syndrome is less common in adults, leading to clinical challenges and delayed diagnosis (> 1 month). Reduction combined with a halo vest treatment failed, and the patient required cervical arthrodesis.

Le syndrome de Grisel est une subluxation atlanto-axoïdienne (C1-C2) non traumatique et l'une des causes de torticolis chez l'enfant. La subluxation survient dans le cadre d'une infection de la sphère ORL ou à la suite d'une chirurgie. Le diagnostic est basé sur la clinique et l'examen radiologique. Le traitement est le plus souvent médical et conservateur. Les prises en charge chirurgicales sont limitées aux récidives et aux présentations tardives.Nous discutons ici deux cas de subluxation C1-C2. La première chez un enfant de 10 ans faisait suite à une rhinopharyngite. Cette présentation correspond à la présentation typique du syndrome de Grisel. Une prise en charge rapide a permis une correction de cette subluxation à l'aide d'un traitement médical et d'une minerve souple de type Philadelphia. Le second cas concerne une adulte de 34 ans qui a présenté des céphalées postérieures à la suite d'une chirurgie de sphénoïdotomie. Le syndrome Grisel est moins fréquent chez l'adulte, ce qui a engendré une errance clinique et un diagnostic retardé (> 1 mois). La réduction associée à un traitement par haloveste a échoué et la patiente a nécessité une arthrodèse cervicale.

STRANGULATION-INDUCED ATLANTOAXIAL ROTATORY SUBLUXATION TREATED WITH CLOSED REDUCTION.

BACKGROUND: Cervical subluxation is a broad class of injuries in which there are degrees of misalignment of vertebral bodies in relationship to adjacent vertebra. Atlantoaxial rotatory subluxation (AARS) is a subtype of cervical subluxation resulting from exaggerated rotation of the C1-C2 complex. Inflammatory, infectious, post-surgical, and traumatic etiologies are recognized and well-described. AARS is predominantly seen in children and occurs rarely in adults. CASE REPORT: We submit the case of an otherwise healthy adult male patient presenting to the emergency department with strangulation-induced C1-C2 subluxation with a rotational component that was treated at the bedside by neurosurgery with closed reduction. Why Should an Emergency Physician Be Aware of This? Clinicians must consider a broad range of serious pathologies in a patient presenting with torticollis, especially in the setting of strangulation. Although extremely rare in adults, AARS must be considered in the differential diagnosis, as early identification increases the likelihood of successful nonoperative treatment.

Cervical MRI assessment of traumatic anterior atlanto-occipital membrane complex injuries with evaluation of ancillary findings.

BACKGROUND AND PURPOSE: The purpose of this study was to identify and classify the different types of anterior atlanto-occipital membrane complex injuries on MRI and evaluate for the presence, size, and location of a prevertebral effusion on the preceding CT exams. MATERIALS AND METHODS: Patients who suffered an anterior atlanto-occipital membrane complex injury were identified retrospectively utilizing Nuance mPower software. An anatomic-based description of the location of the anterior atlanto-occipital membrane complex injury was recorded along with any additional osteoligamentous trauma of the craniocervical junction. The preceding cervical CT exams for these patients were reviewed for the presence and location of a prevertebral effusion. RESULTS: Fifty patients were identified with an acute, post-traumatic anterior atlanto-occipital membrane complex injury. Three distinct patterns of anterior atlanto-occipital membrane complex injury were observed. Nineteen patients demonstrated increased STIR signal with disruption of the anterior atlanto-occipital membrane, ten patients demonstrated increased STIR signal with disruption of the anterior atlanto-axial membrane, and twenty-one patients demonstrated increased STIR signal with disruption of both the anterior atlanto-occipital membrane and anterior atlanto-axial membrane. An effusion at the C1-C2 level was present in greater than 90% of patients with anterior atlanto-occipital membrane complex injury. CONCLUSIONS: The presence of a craniocervical prevertebral effusion on CT in trauma patients may raise suspicion for an injury to the anterior atlanto-occipital membrane complex and potentially trigger additional investigation with cervical MRI.

Transoropharyngeal closed reduction for traumatic atlantoaxial dislocation: a novel technique for fast and precise reduction.

PURPOSE: The aim of this study is to introduce a new technique for the rapid and accurate reduction of traumatic atlantoaxial dislocation (TAAD) and to investigate its radiological and clinical outcomes. METHODS: The clinical outcomes of 18 patients who were diagnosed with acute TAAD and underwent rapid transoropharyngeal closed reduction in our hospital were retrospectively analyzed from January 2015 to December 2020. Following general anaesthesia, all patients were immediately treated with oropharyngeal reduction under somatosensory evoked potential monitoring. The Japanese Orthopedic Association score, neck disability index and visual analog scale score for neck pain were used to evaluate clinical efficacy. Atlantodental distance, posterior atlantodental interval, and the clivus-canal angle were used to assess reduction and spinal cord compression. RESULTS: The mean follow-up time was 23.3 months, with a range of 13-38 months. No neurovascular injury occurred during the operations. For all patients, the closed reduction method through the oropharynx under general anaesthesia was successful, and the success rate of reduction was 100%. All patients recovered uneventfully with marked improvement in clinical outcomes and imaging parameters (P < 0.01). Two patients developed mild postoperative dysphagia. One patient developed postoperative fever and pulmonary infection. CONCLUSION: Rapid trans-oropharyngeal closed reduction can safely, effectively, and rapidly reduce acute TAAD. This method provides a new strategy for treatment of the condition.

A rare case of atlantoaxial rotatory fixation after posterior calvarial vault expansion surgery in a Crouzon patient.

INTRODUCTION: Atlantoaxial rotatory fixation (AARF) is a rare condition that occurs most commonly in children. The torticollis caused by AARF usually presents as abnormal posturing of the head and neck, with rotation of the chin to the opposite side. AARF in children could occur due to congenital bony malformation, minor trauma, upper respiratory tract infections (Grisel's syndrome), postoperatively after head and neck (ENT) surgery, and unknown reasons. AARF in the postoperative patient is a rare and poorly understood entity. METHODS: The authors present a case report of a 2-year-old boy with Crouzon Syndrome undergoing posterior calvarial vault expansion (PVE) surgery that developed AARF as a complication. RESULTS: The authors believe that cranial vault surgery should be considered a potential risk procedure for AARF, especially if it is done in susceptible populations (syndromic craniosynostosis patients) with other underlying sequelae (tonsillar ectopia or syringomyelia). During surgery, careful attention should be paid to maintaining a neutral alignment of the patient's cervical spine as rotatory movements under anaesthesia and muscle relaxation may be contributory factors. CONCLUSION: AARF should be suspected and investigated in children with painful torticollis after craniofacial surgery.

A case of atlantoaxial dislocation associated with ipsilateral vertebral and carotid artery dissections: highlighting the injury biomechanics and management strategy.

INTRODUCTION: Traumatic cervical artery dissections carry significant morbidity and mortality among blunt trauma victims. The current paper illustrates a case with a young male who presented with atlantoaxial dislocation associated with ipsilateral carotid and vertebral artery dissections complicated by middle cerebral artery (MCA) infarction. CASE REPORT: We report a young male who presented to the emergency department with ipsilateral carotid and vertebral artery dissections complicated by middle cerebral artery (MCA) stroke associated with atlantoaxial dislocation after jumping into the water from a height. A young patient presented to us 1 year after sustaining an injury. We did posterior C1/2 fusion using the technique described by Harms and Goel to treat his atlantoaxial dislocation. The patient tolerated the surgery well and was discharged on postoperative day 4. CONCLUSIONS: We highlighted the complicated course of the simultaneously traumatic dissections of ipsilateral cervical arteries along with atlantoaxial dislocation, the biomechanics of this combination of injuries, and their management strategy.

Basilar invagination without atlantoaxial dislocation: treatment by correction of clivus canal angle with interfacet distraction and fixation.

BACKGROUND: This study reports on the surgical technique used and clinical outcomes obtained during the treatment of basilar invagination (BI) without atlantoaxial dislocation (AAD) through the correction of the clivus canal angle (CCA) using interfacet distraction and fixation. METHODS: Nineteen cases with BI without AAD treated by the correction of the clivus canal angle were retrospectively analyzed. Pre- and postoperative computed tomography scans and three-dimensional reconstruction views were obtained to measure the size of the CCA, pB-C2 distance, and degree of BI. Chiari malformation and syringomyelia were evaluated by magnetic resonance imaging (MRI). The clinical outcomes for all patients were measured using the Japanese Orthopedic Association (JOA) scale. The CCA was corrected by using interfacet distraction and fixation techniques. The Wilcoxon test was used to compare pre- and postoperative measurements. RESULTS: All the patients were followed up for 24.95 ± 5.22 months (range 12-36 months); no patient suffered intraoperative nerve or vascular injury. Clinical symptoms improved in 17 patients (89.5%). The mean JOA score increased from 12.32 ± 1.89 to 14.37 ± 1.30 (Z = -3.655, P < 0.001). The mean CCA improved from 129.34 ± 8.52° preoperatively to 139.75 ± 8.86° postoperatively (Z = -3.824, P < 0.001). The mean pB-C2 decreased from 7.47 ± 2.21 to 5.68 ± 3.13 (Z = -3.060, P = 0.002). Syringomyelia was significantly reduced in 10 out of 13 patients by the first follow-up year. All patients achieved bony fusion. CONCLUSION: Posterior interfacet distraction and fixation to correct the CCA is a feasible and effective method for treating BI without AAD.

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

Although historically considered fatal, with the advent of improved pre-hospital care, traumatic dislocation of the craniovertebral junction (CVJ) has been increasing in prevalence in neurosurgical centers. As more survivors are reported each year, a timely review with meta-analysis of their management seems necessary. PRISMA checklist was followed step by step. PubMed and Web of Science databases were searched using words "craniovertebral junction dislocation" and their corresponding synonyms. Study eligibility criteria included research studies from 2015 onwards that delineated adult and pediatric patients with confirmed post-traumatic atlantooccipital dislocation (AOD) or atlantoaxial dislocation (AAD) who survived until proper treatment. Of 1475 initial records, 46 articles met eligibility criteria with a total of 141 patients with traumatic CVJ dislocation. Of the patients, 90 were male (63.8%). Mean age of the cohort was 33.3 years (range 1-99 years). Trauma that most often led to this injury was road traffic accident (70.9%) followed by falls (24.6%). The majority of authors support posterior instrumentation of C1-C2 (45.2%) especially by means of Goel-Harms method. At mean follow-up of 15.4 months (range 0.5-60 months), 27.2% of treated patients remained neurologically intact. Of initially symptomatic, 59% improved, 37% were stable, and 4% deteriorated. Instrumenting the occiput in cases of pure AAD was associated with lower chance of neurological improvement in chi-square test (p = 0.0013) as well as in multiple linear regression (ß = - 0.3; p = 0.023). The Goel-Harms C1-C2 fusion is currently the most frequently employed treatment. Many survivors remain with no deficits or improve, rarely deteriorate. Involving the occiput in stabilization in cases of AAD without AOD might be related with worse neurological prognosis.

Surgical treatment of neglected C2 odontoid process fracture with anterior atlantoaxial dislocation.

We report a case of the atlantoaxial (C1-2) deformity secondary to a neglected C2 odontoid fracture that was successfully treated with 3-stage operation performed in one session.

Effectiveness of posterior reduction and fixation in atlantoaxial dislocation: a retrospective cohort study of 135 patients with a treatment algorithm proposal.

PURPOSE: Surgical procedures on atlantoaxial dislocation remain controversial. The aim of this observational retrospective study was to investigate the treatment algorithm of surgical procedures. METHODS: According to CT and intraoperative evaluation during direct posterior reduction, 135 AAD cases were categorized into three groups: Group I: reducible dislocation; Group II: irreducible dislocation (Group IIa: effective decompression achieved after posterior reduction; Group IIb: no effective decompression after posterior reduction); and Group III: fixed dislocation. Group III presented with extensive bony fusions. Group I and Group IIa were treated with direct posterior reduction and fixation. Group IIb underwent posterior fixation and transoral odontoidectomy. Group III underwent transoral odontoidectomy alone. Japanese Orthopedic Association scores (JOA) were assessed to evaluate clinical status before and 6, 12 months after surgery. RESULTS: Our study included 118 Group I cases, 16 Group II cases (Group IIa: 11 cases; Group IIb: 5 cases), and one Group III case. Follow-up ranged from 12 to 36 months. PRIMARY OUTCOME: Anatomic atlantoaxial reduction was achieved in 118 of 135 patients (87.4%). Clinical improvements were seen in 96.3% (130/135) all the patients. Solid atlantoaxial fusion was shown in 134 patients. Secondary outcome: The overall complication rate was 3.7% (5/135). For Group I, the mean postoperative 6-month JOA was 14.5 versus 12.2 in preoperative patients (paired Student's t test, P < 0.01). CONCLUSIONS: This article proposes a clinical procedure that assists with therapeutic decision making and indicates the severity and difficulty of reduction of the atlantoaxial joint. These slides can be retrieved under Electronic Supplementary Material.

Apparent diffusion coefficient as an indicator of spinal cord compression due to anterior atlanto-axial subluxation in rheumatoid arthritis patients.

PURPOSE: The aim of this retrospective study was to evaluate the apparent diffusion coefficient (ADC) as a potential parameter of spinal cord damage in cervical spine instability at the atlanto-axial level in rheumatoid arthritis (RA) patients. METHODS: One hundred and six RA patients were included in the study. MRI examinations were performed with 1.5T scanner. The ADC was measured at six locations in the cervical spinal cord at the height of the first six cervical vertebrae (from C-1 to C-6). The ADC values were assessed in 2 groups: with and without anterior atlanto-axial subluxation (AAS) diagnosed on plain radiographs. Correlations between ADC values and radiographic measurements and RA activity indicators were evaluated. RESULTS: The ADC values at C1 level (ADC1) was higher in the group with anterior AAS than in the group without AAS (p < 0.001). Statistically significant moderate positive correlation between ADC1 and anterior atlanto-axial diameter interval AADI (rho = 0.58; p < 0.008) was found as well as statistically significant weak negative correlation between ADC1 and posterior atlanto-axial diameter interval PADI (rho = - 0.34; p < 0.008). CONCLUSIONS: The conducted study demonstrates the applicability of the ADC maps in the identification of spinal cord compression due to anterior AAS in RA patients. The results encourage the practical use of the ADC as an additional parameter in the qualification for surgical treatment. These slides can be retrieved under Electronic Supplementary Material.

Posterior atlantoaxial dislocation without fracture or neurological symptoms treated by transoral-posterior approach surgery: a case report and literature review.

BACKGROUND: Atlantoaxial dislocation usually results from hyperextension trauma and is almost always accompanied by odontoid fracture and neurological symptoms. In most cases, patients with atlantoaxial dislocation die instantly. This is a rare report of posterior atlantoaxial dislocation without fracture and neurological symptoms effectively treated by transoral-posterior approach surgery, and only eleven similar cases have been previously reported. OBJECTIVE: To describe the very rare case of an adult posterior atlantoaxial dislocation patient without fracture who was neurologically treated using transoral-posterior approach surgery and to review the relevant literature. METHOD: A 52-year-old man riding a motorcycle was rear-ended by a car. Using X-ray, computed tomography (CT) scan and magnetic resonance imaging (MRI), he was diagnosed with posterior atlantoaxial dislocation without a related fracture or a significant change in spinal cord signal. Transoral-posterior approach surgery with sustained skull traction was used after failed closed reduction. RESULT: During a 6-month follow-up observation, the lateral cervical spine radiography and sagittal reconstructions of CT scans demonstrated no instability of the atlantoaxial complex. Few patients experience posterior atlantoaxial dislocation without a related fracture or spinal cord deficit. For a patient who experiences trauma with hyperextension, such as in rear-end collisions, X-ray, CT scan and MRI should be performed to ensure that this injury is diagnosed. It is necessary to perform surgery to recover atlantoaxial stability, even in the absence of fracture or neurological symptoms. CONCLUSION: Transoral-posterior approach surgery is a safe and effective way to manage irreducible posterior atlantoaxial dislocation.

Traumatic atlantoaxial rotatory fixation in an adult patient.

INTRODUCTION: Atlantoaxial rotational fixation (AARF) is a rare entity in adults, with only a few cases reported in the English literature and often associated with a traumatic mechanism. It is an underdiagnosed condition that must be taken into account in the initial assessment of all craniocervical trauma. Both diagnostic and therapeutic delay may be a potential cause of severe neurological damage or even death of the patient. The therapeutic management is controversial given the difficulty of achieving optimum stability and permanent reduction. METHODS AND RESULTS: A 28-year-old woman was involved in a traffic accident a week before coming to the emergency with rotation and irreducible cervical flexion from trauma and severe neck pain. CT and MRI column were performed and showed a cervical spinal AARF with transverse and alar ligaments intact and preserved atlantoaxial distance (Fielding I). The patient was treated by progressive cervical traction with 5 kg and manual reduction was completed in 24 h. Subsequently, an external immobilization was performed by cervical rigid collar for 16 weeks. The clinical course was good, with the patient regaining full mobility with cervical neck pain improvement. CONCLUSIONS: The purpose of this paper is to show a case of a young woman with a posttraumatic AARF successfully treated conservatively. This case delineates the difficulties in diagnosing this pathology, as well as the challenges encountered in its management.

Posttraumatic Anatomical Injuries of the Craniovertebral Junction and Treatment Implications: Part II.

This paper is Part II of a two-part report. In Part I of the report, injuries of the occipital bone, atlanto-occipital dissociation and the atlanto-occipital joint space were discussed. This part of the report discusses atlantoaxial dislocation and fractures of the atlas and axis.

Traumatic posterior Atlanto-axial dislocation: case report of an atypical C1-C2 dislocation with an anterior arch fracture of C1.

BACKGROUND: An atypical case of a traumatic posterior C1-C2 dislocation with an anterior arch fracture of C1 is reported. A novel conservative treatment for this rare lesion is described. CASE PRESENTATION: An eighty-nine-year-old male fell off a ladder at home and presented with an acute traumatic cervical spine trauma, which we believe involved a distraction mechanism. The patient was neurologically intact; he denied any weakness, numbness or paresthesia. A preoperative CT-scan demonstrated a posterior dislocation with an anterior arch of C1 fracture. Conservative management was elected. Reduction was achieved by closed manual reduction under general anesthesia. A postoperative CT demonstrated a complete reduction of the atlanto-axial dislocation. CONCLUSION: Based on this case report and relevant literature, we present an unusual lesion of the upper cervical spine treated nonoperatively with closed manual reduction under general anesthesia. To date, there is no available consensus for the management of these lesions.