Thomas A, S. Vadakkedam S, K. P, M. A. Bow Hunter's Syndrome with Rotational Atlantoaxial Instability: A Rare Association

Bow Hunter's syndrome (BHS) is a very rare condition in which there is rotational vertebral artery (VA) insufficiency. The association of BHS with rotational atlantoaxial instability is extremely rare. We are reporting a case of pediatric BHS who presented with features of VA insufficiency on neck rotation. Careful evaluation revealed rotational C1-C2 instability. Provocative digital subtraction angiography and dynamic neck computed tomography were the mainstay of our diagnostic armamentarium. Our case emphasizes the fact that VA abnormalities need special consideration in young patients with craniovertebral junction instability and a high degree of suspicion is necessary in most instances for accurate diagnosis.

Posterior Release, Reduction, and Intra-Articular Fusion for Irreducible Type III Atlantoaxial Rotary Fixation

BACKGROUND AND OBJECTIVES

For irreducible atlantoaxial rotary fixation (AARF), anterior or posterior release was often needed before posterior reduction and fusion. Anterior atlantoaxial joint release has potential complications such as retropharyngeal abscess, persistent hoarseness, and infection. This study aims to assess the efficacy of posterior release, reduction, and intra-articular fusion without resecting the C2 nerve root on irreducible type III AARF.

METHODS

The data of 9 pediatric patients diagnosed with AARF who underwent posterior atlantoaxial release, reduction, and intra-articular fusion without resecting the C2 nerve root were retrospectively reviewed. Japanese Orthopaedic Association scores and Visual Analog Scale for Neck Pain were used to assess outcomes. The preoperative and follow-up assessments of atlantodens interval (ADI) were documented to evaluate the reduction of atlantoaxial joint. The patient demographics, surgery time, blood loss, bone fusion time, follow-up period, and surgery-related complications were meticulously documented.

RESULTS

The mean follow-up duration was 35.1 ± 11.5 months. Complete reduction was achieved in 8 patients, while one patient did not achieve complete reduction. The ADI decreased significantly from 8.7 ± 2.2 mm before surgery to 2.1 ± 1.3 mm at the final follow-up. All patients demonstrated successful bone fusion, with an average fusion period of 3.7 ± 1.3 months. The Visual Analog Scale for Neck Pain at the final follow-up exhibited a significant decrease compared with preoperative values (P < .05), while no significant difference was observed in Japanese Orthopaedic Association scores. There were no complications related to surgery.

CONCLUSION

Posterior atlantoaxial release, reduction, and intra-articular fusion with a C2 nerve root preservation technique is effective in the treatment of irreducible type III AARF.

C1 Transposterior Arch Lateral Mass Screws Combined With C2 Pedicle Screw and Rod Fixation for Pediatric Atlantoaxial Subluxation: A Minimal 10-Year Follow-up Outcome Analysis

BACKGROUND AND OBJECTIVES

Although the short-term outcomes of the 1-step reduction and fixation technique using C1 transposterior arch lateral mass screws combined with C2 pedicle screw and rod fixation system for the treatment of pediatric atlantoaxial subluxation (AAS) have been satisfactory, its long-term outcomes and impact on spinal development are not well studied. This study was intended to assess the long-term reliability of this technique for pediatric AAS.

METHODS

A retrospective case series study was conducted to analyze the minimum 10-year follow-up outcomes from 7 pediatric patients with AAS who underwent atlantoaxial fusion using the aforementioned technique. Quality of life and cervical range of motion were both measured thoroughly. In addition, vertical growth within the fusion construct (C1-2), overall cervical alignment, and subaxial cervical spine degeneration were evaluated radiographically.

RESULTS

The mean age of the 7 patients was 8.14 ± 2.41 (6-12) years at the time of surgery. The mean follow-up period was 11.00 ± 1.15 (10-13) years. No patients presented identifiable intervertebral disk degeneration or segmental instability in the subaxial cervical spine except for 1 patient who showed mild intervertebral disk degeneration. Vertical growth did continue within the atlantoaxial complex after surgery (11.90% ± 2.37%); however, there was a decrease in the percentage of vertical growth compared with the corresponding normal populations of the same age and sex. Moreover, there was a significant decrease in the range of cervical extension and rotation motion, and the overall cervical alignment straightened at the latest follow-up.

CONCLUSION

The 1-step reduction and fixation technique is a relatively reliable surgical technique for pediatric AAS, which does not adversely affect the postoperative quality of life or the subaxial cervical degeneration. Nevertheless, certain limitations, such as decreased cervical range of motion and changes in cervical alignment, should be concerned.

C1-C2 subluxation in enthesitis-related arthritis: two case reports and literature review of ten cases

BACKGROUND

C1-C2 subluxation is a rare complication of enthesitis-related arthritis (ERA). If left untreated, it may lead to functional impairment or cervical spinal cord compression. This study aims to highlight key points regarding the management of C1-C2 subluxation in ERA.

CASE PRESENTATION

We present two cases of C1-C2 subluxation: an 8-year-old boy with ERA and 16-year-old boy with ERA with bilateral sacroiliitis. Ten cases of ERA in the literature were reviewed. The diagnosis of C1-C2 subluxation is mostly based on radiographs and cervical spine computed tomography. All patients were treated with non-steroidal anti-inflammatory drugs. Six ERA patients were treated surgically for cervical fusion. Most ERA patients with sacroiliitis had cervical collar protection. Neurologic abnormalities after treatment were not reported. Despite the use of cervical collar, cervical fusion and persisting ankylosis were found in two ERA patients with sacroiliitis without surgical treatment.

CONCLUSIONS

Cervical spine protection and ruling out spinal cord compression should be prioritized, in addition to controlling the underlying inflammation in ERA. Cervical halter traction may be applied after severe cervical inflammation is excluded. To reduce the risk of complications, early recognition and appropriate treatments of C1-C2 subluxation in ERA are essential.

Treating Pediatric Irreducible Atlantoaxial Rotatory Fixation (IAARF) by Unlocking Facet Joint Through Transoral Approach and Fixing With Slim-TARP Plate (15 Cases Series)

BACKGROUND

Irreducible atlantoaxial rotatory fixation (IAARF) often requires surgical treatment. Transoral unlocking the facet joints is a key measure for the treatment of IAARF. We investigate a novel method for treating pediatric IAARF by unlocking facet joint through transoral appraoch and fixed with slim-tarp plate in same stage with same approach.

OBJECTIVE

The objective of this study is to investigate the method and efficacy of a unique transoral approach to unlock facet joints and fixation with slim-shaped transoral anterior reduction plate (slim-TARP) plate in the treatment of IAARF.

METHODS

Fifteen patients diagnosed with AARF were transferred to our hospital. After 1 week of bidirectional cervical cranial traction, they were diagnosed with irreducible AARF that, and then underwent transoral release and fixation with slim-TARP plate procedures. Postoperative computed tomography and magnetic resonance were used to evaluate the reduction effect, bone fusion, and fusion time. Japanese orthopaedic association scores were used to compare the recovery of spinal cord function in patients before and after surgery. Complications such as wound infection, neurovascular injury, and loosening of internal fixation were evaluated too.

RESULTS

All 15 patients underwent transoral unlocking facet joint and fixation with slim-TARP procedures smoothly. The operation time were 129.2±11.9 minutes, blood loose were 83±23 mL. There were no neurological injury, wound infections, verified or suspected vertebral artery injury, etc. All patients were followed up for a mean of 17.8±6.6 months (range: 12 to 36 mo). Bony fusion was achieved in all patients. Mean fusion time was 3.6±1.2 months (range: 3 to 6 mo). Complete correction of torticollis was achieved in all 15 cases. Preoperative symptoms of neck pain and limitation of neck movement were effectively alleviated at 3 months after surgery. The 3 patients with preoperative neurological deficits had significant relief after surgery, and their latest follow-up results showed that their Japanese orthopaedic association scores increased from 13.0±1.0 to 16.3±0.6.

CONCLUSIONS

Transoral release and fixation with slim-TARP plate by transoral approach is a feasible and safe method for treating pediatric irreducible atlantoaxial rotatory fixation.

Atlantoaxial rotatory dislocation: Surgical treatment in a pediatric patient cohort

•Surgical correction of AARD is an appropriate method of treatment after failed non-operative therapy.•The technique of surgical reduction and C1-C2 fixation using Harms/Goel technique provides excellent clinical outcomes.•In case of traumatic AARD we recommend to consider temporary fixation.

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.

C1-C2 Rotatory Subluxation in Adults “A Narrative Review”

The atlantoaxial joint C2 (axis) with the anterior arch of C1 (atlas) allows 50% of cervical lateral rotation. It is responsible for precise and important movements that allow us to perform precise actions, both in normal and working life. Due to low incidence in adults, this condition often goes undiagnosed, or the diagnosis is delayed and the outcome is worse. An early diagnosis and treatment are essential to ensure satisfactory neurological and functional outcomes. The aim of this review is to analyze C1-C2 rotatory subluxation in adults, given its rarity. The time between injury and reduction is key, as it is directly related to prognosis and the severity of the treatment options. Due to low incidence in adults, this condition often goes undiagnosed, or the diagnosis is delayed as a lot of cases are not related to a clear trauma, with a poor prognosis just because of the late diagnosis and the outcome is worse. The correct approach and treatment of atlantoaxial dislocation requires a careful study of the radiological findings to decide the direction and plane of the dislocation, and the search for associated skeletal anomalies.

Brain pathological changes during neurodegenerative diseases and their identification methods: How does QSM perform in detecting this process?

The presence of iron is essential for many biological processes in the body. But sometimes, for various reasons, the amount of iron deposition in different areas of the brain increases, which leads to problems related to the nervous system. Quantitative susceptibility mapping (QSM) is one of the newest magnetic resonance imaging (MRI)-based methods for assessing iron accumulation in target areas. This Narrative Review article aims to evaluate the performance of QSM compared to other methods of assessing iron deposition in the clinical field. Based on the results, we introduced related basic definitions, some neurodegenerative diseases, methods of examining iron deposition in these diseases, and their advantages and disadvantages. This article states that the QSM method can be introduced as a new, reliable, and non-invasive technique for clinical evaluations.

Torticollis in childhood-a practical guide for initial assessment

Torticollis is encountered often in the paediatric setting and should be considered a presenting symptom, rather than a diagnosis. Aetiologies of torticollis are numerous, and the nomenclature describing underlying diagnosis can be confusing. Furthermore, children with torticollis typically present in the first instance to primary or secondary care rather than to the subspecialist. These factors can contribute to erroneous treatment of this patient-group which could be time critical in some instances. In this review, we discuss the common causes for torticollis and propose a simple clinical assessment tool and early management scheme that will assist in the differential-diagnosis and treatment pathway of this challenging condition.Conclusion: Torticollis can be the initial presentation of various conditions. The diagnosis and management tools provided in this article can aid in guiding paediatricians as to the correct initial management, imaging, and specialist referral. What is Known: • Torticollis in childhood is a very common presenting symptom with numerous aetiologies. • Management is complex, requires multiple clinical and imaging examinations, and is usually performed by non-specialized professionals. What is New: • A new, simple clinical-assessment tool under the acronym PINCH designed to aid paediatric general practitioners in diagnosing correctly the aetiology of torticollis. • A practical management scheme to aid in the treatment pathway of children with torticollis.

Concomitant atlantoaxial and atlanto-occipital rotatory dislocation in children: Radiological features, diagnostic pitfalls, and long-term outcome

While the pathological manifestation of atlantoaxial rotatory dislocation has been well described in the medical literature, the combined dislocation of the atlantoaxial and atlanto-occipital joints, or OAARD - short for occipital-atlantoaxial rotatory dislocation - is a condition which has been poorly elucidated and probably underdiagnosed. We believe that the pathogenesis of combined atlantoaxial and atlanto-occipital dislocation is most likely a result of untreated atlantoaxial rotatory dislocation leading to chronic secondary compensation measures occurring at the occiput-C1 joints. Unique clinical and radiological features lead to difficulty in diagnosis, and conventional treatment algorithms may not apply. This paper describes a combination of clinical and radiological features which can help clinicians correctly diagnose and treat OAARD.

Natural History, Neuroradiological Workup, and Management Options of Chronic Atlantoaxial Rotatory Fixation Caused by Drug-Induced Cervical Dystonia

Atlantoaxial rotatory fixation (AARF) resulting from drug-induced cervical dystonia (DICD) represents an extremely rare complication of antipsychotic treatment, requiring a comprehensive assessment of pharmacologic therapy and timely radiologic workup. We report a chronic case of Fielding type I, Pang type I AARF secondary to schizophrenia treatment in a 16-year-old girl, along with a review of the literature on the management challenges posed in this condition. In this scenario, torticollis may just represent the tip of the iceberg, and only an effective multidisciplinary approach increases the chances of satisfactory correction with closed reduction, hence avoiding the burden of more invasive treatment options.

Atlantoaxial rotatory subluxation/fixation and Grisel's syndrome in children: clinical and radiological prognostic factors

Atlantoaxial rotatory subluxation/fixation (AARS/F) is a rare cause of torticollis in children. The aim of our study is to investigate all possible clinical and radiological prognostic factors in children with AARS/F. We retrospectively reviewed all cervical spine CT scans of children with AARS/F treated in our Hospital over the last 15 years. AARS/F was classified according to Fielding and Hawkins classification and C1-C2 rotation-degree was calculated. Moreover, two orthopedic surgeons reviewed all clinical reports of these children. All patients were conservatively treated (cervical traction/neck collar). An early recovery was considered in patients with complete clinical/radiological healing at 3 months follow-up, while a late recovery was considered in patients with disease persistence or relapse at 3 months follow-up or earlier. Fifty-five patients with diagnosis of AARS/F were included in the study (mean age = 8.5 years old - 25F, 30M). In 9/55 subjects (16.4%), a late recovery was observed. The presence of a concomitant infection or inflammation in the head and neck region (Grisel's syndrome) was significantly associated with a late recovery (p < .001). Also, the type of AARS/F (p = .019), according to the Fielding and Hawkins classification, and C1-C2 rotation-degree (p = .027) were significantly correlated with the recovery time.Conclusion: In patients with AARS/F, the presence of a concomitant infection/inflammation in the head and neck region is the most important prognostic factor and it is associated with a late recovery. The Fielding and Hawkins classification and C1-C2 rotation-degree well correlate with patients' recovery time. What is Known: • Atlantoaxial rotatory subluxation/fixation (AARS/F) is a rare cause of torticollis in children and CT is the most useful imaging tool for diagnosis and classification of AARS/F. • Conservative treatments are effective in the majority of pediatric patients with AARS/F. What is New: • The presence of a concomitant infection/inflammation in the head and neck region associated with AARS/F (Grisel's syndrome) is the most important prognostic factor and it is associated with a late recovery. • C1-C2 rotation-degrees, as well as Fielding and Hawkins classification system, well correlate with patients' recovery time.

Systematic review of the nonsurgical management of atlantoaxial rotatory fixation in childhood

OBJECTIVE

Atlantoaxial rotatory fixation (AARF) is an acquired fixed abnormality of C1-2 joint rotation associated with torticollis in childhood. If the condition is left uncorrected, patients are at risk for developing C1-2 fusion with permanent limitation in the cervical range of movement, cosmetic deformity, and impact on quality of life. The management of AARF and the modality of nonsurgical treatment are poorly defined in both primary care and specialized care settings, and the optimal strategy is not clear. This systematic review aims to examine the available evidence to answer key questions relating to the nonsurgical management of AARF.

METHODS

A systematic review was performed using the following databases: PubMed, MEDLINE, Healthcare Management Information Consortium (HMIC), EMCare, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), British Nursing Index (BNI), and Allied and Complementary Medicine Database (AMED). Search criteria were created and checked independently among the authors. All articles with a radiological diagnosis of AARF and primary outcome data that met the study inclusion criteria were included and analyzed by the authors.

RESULTS

Search results did not yield any level I evidence such as a meta-analysis or randomized controlled trial. The initial search yielded 724 articles, 228 of which were screened following application of the core exclusion criteria. A total of 37 studies met the full criteria for inclusion in this review, consisting of 4 prospective studies and 33 retrospective case reviews. No articles directly compared outcomes between modalities of nonsurgical management. Six studies compared the outcome of AARF based on duration of symptoms before initiation of treatment. Comparative analysis of studies was hindered by the wide variety of treatment modalities described and the heterogeneity of outcome data.

CONCLUSIONS

The authors did not identify any level I evidence comparing different nonsurgical management approaches for AARF. There were few prospective studies, and most studies were uncontrolled, nonrandomized case series. Favorable outcomes were often reported regardless of treatment methods, with early treatment of AARF tending to yield better outcomes independent of the treatment modality. There is a lack of high-quality data, and further research is required to determine the optimal nonsurgical treatment strategy.

Atlantoaxial rotatory fixation in childhood: a staged management strategy incorporating manipulation under anaesthesia

AIMS

The aims were to evaluate the safety of manipulation under anaesthesia (MUA) for atlantoaxial rotatory fixation (AARF) and the relative efficacy of rigid collar vs halo-body orthosis (HBO) in avoiding relapse and the need for open surgery.

METHODS

Cases of CT-verified AARF treated by MUA were identified from a neurosurgical operative database. Demographic details, time to presentation and aetiology of AARF were ascertained through case note review. Cases were divided according to method of immobilisation after successful reduction, either rigid collar (group 1) or HBO (group 2). The primary outcome measure was relapse requiring open surgical arthrodesis.

RESULTS

Thirty-three patients (2.2-12.7 years) satisfied inclusion criteria. Time to presentation varied from 1 day to 18 months. There were 19 patients in group 1 and 14 in group 2. There were no adverse events associated with MUA. 9/19 (47%) patients in group 1 resolved without need for further treatment compared with 10/14 (71%) in group 2 (p = 0.15). Of the 10 patients who failed group 1 treatment, four resolved after HBO. A total of ten patients (30%) failed treatment and required open surgery.

CONCLUSIONS

MUA is a safe procedure for AARF where initial conservative measures have failed. MUA followed by immobilisation avoids the need for open surgery in over two thirds of cases. Immobilisation by cervical collar appears equally effective to HBO as an initial management, and so a step-wise approach may be reasonable. Delayed presentation may be a risk factor for relapse and need for open surgery.

Intraoperative Use of Cone-Beam Computed Tomography in the Treatment of Atlantoaxial Rotatory Subluxation

BACKGROUND

Atlantoaxial rotatory subluxation (AARS) is a rare pathological condition of the upper cervical spine. It can be caused by multiple mechanisms, including minor neck manipulations. Children are more prone owing to the weaker periarticular soft tissue and a steeper slant of the C1 facet plane against the vertical axis of the dens. If AARS does not resolve spontaneously, a normal position of the atlantoaxial joint must be achieved by reduction and stabilization.

CASE DESCRIPTION

A 15-year-old girl had presented with a painful torticollis that had already been present for 4 weeks after trimaxillary jaw correction for skeletal class II malocclusion. A computed tomography (CT) scan of the cervical spine showed AARS Field and Hawkins classification type I. We first attempted 1 week of conservative treatment with a soft collar and the prescription of a muscular relaxant. However, because the AARS persisted, we performed transoral closed reduction with the patient under general anesthesia, as previously described. During the procedure, we used intraoperative cone-beam CT to evaluate the degree of reduction. After obtaining complete reduction, immobilization with a halo-vest was applied.

CONCLUSIONS

Complete reduction of the AARS was achieved with closed intraoral reduction. We used intraoperative cone-beam CT to confirm complete reduction. We found cone-beam CT to be a very useful tool.

3T MRI Whole-Brain Microscopy Discrimination of Subcortical Anatomy, Part 2: Basal Forebrain

BACKGROUND AND PURPOSE

The basal forebrain contains multiple structures of great interest to emerging functional neurosurgery applications, yet many neuroradiologists are unfamiliar with this neuroanatomy because it is not resolved with current clinical MR imaging.

MATERIALS AND METHODS

We applied an optimized TSE T2 sequence to washed whole postmortem brain samples (n = 13) to demonstrate and characterize the detailed anatomy of the basal forebrain using a clinical 3T MR imaging scanner. We measured the size of selected internal myelinated pathways and measured subthalamic nucleus size, oblique orientation, and position relative to the intercommissural point.

RESULTS

We identified most basal ganglia and diencephalon structures using serial axial, coronal, and sagittal planes relative to the intercommissural plane. Specific oblique image orientations demonstrated the positions and anatomic relationships for selected structures of interest to functional neurosurgery. We observed only 0.2- to 0.3-mm right-left differences in the anteroposterior and superoinferior length of the subthalamic nucleus (P = .084 and .047, respectively). Individual variability for the subthalamic nucleus was greatest for angulation within the sagittal plane (range, 15°-37°), transverse dimension (range, 2-6.7 mm), and most inferior border (range, 4-7 mm below the intercommissural plane).

CONCLUSIONS

Direct identification of basal forebrain structures in multiple planes using the TSE T2 sequence makes this challenging neuroanatomy more accessible to practicing neuroradiologists. This protocol can be used to better define individual variations relevant to functional neurosurgical targeting and validate/complement advanced MR imaging methods being developed for direct visualization of these structures in living patients.

Interventional magnetic resonance imaging as a diagnostic and therapeutic method in treating acute pediatric atlantoaxial rotatory subluxation

Atlantoaxial rotatory subluxation or fixation (AARF) is a rare condition, usually occurring in pediatric patients. It mimics benign torticollis but may result in permanent disability or death. The condition requires prompt diagnosis by thorough examination to avoid any treatment delays. Spiral computed tomography (CT) with three-dimensional reconstruction CT is recommended for identifying incongruence between C1 and C2 vertebrae, and magnetic resonance imaging (MRI) may be performed to exclude ligamentous injuries. In addition to static imaging, dynamic CT involves the reduction between C1 and C2 being confirmed using CT with the head turned maximally to the left and right. The present report (level of evidence, III) provides a method for treating AARF that has similar advantages as dynamic CT but avoids ionizing radiation by replacing CT with interventional MRI. The new method comprised simultaneous axial traction and manual closed reduction, performed under general anesthesia, and the use of interventional MRI to ensure that reduction was achieved and held. The head is turned maximally to the right and left during the manual reduction. A rigid cervical collar was used following reduction. Dynamic CT was not required but prior diagnostic static CT was performed in preparation. No further CT was required. There appears to be no previous studies on interventional MRI in AARF care. Being superior in its diagnostic soft-tissue visualization performance and lacking ionizing radiation, interventional MRI is a potential option for investigating and treating acute AARF in non-syndromic patients with no trauma history.

The Healing Rate of Type II Odontoid Fractures Treated With Posterior Atlantoaxial Screw-rod Fixation: A Retrospective Review of 77 Patients

BACKGROUND

In theory, temporary posterior atlantoaxial screw-rod fixation for type II odontoid fractures is a way to preserve rotatory motion. However, the healing rate of type II odontoid fractures treated in this way is unknown; that is, the risk associated with conducting a temporary screw-rod fixation for type II odontoid fractures is unknown. This study investigates the healing rate of type II odontoid fractures treated with posterior atlantoaxial screw-rod fixation by CT imaging and evaluates the feasibility of conducting a temporary screw-rod fixation for type II odontoid fractures.

METHODS

Patients with type II odontoid fracture who underwent posterior atlantoaxial screw-rod fixation in our spine center from January 2011 to December 2014 were identified. Patients older than 65 years or younger than 18 years were excluded. Those who were confirmed to have healing odontoid fractures on CT imaging were included. Those in whom fracture healing was not confirmed were asked to undergo a CT examination. Fracture healing was confirmed on the basis of the presence of bridging bone across the odontoid fracture site on CT imaging.

RESULTS

Seventy-seven patients (56 men and 21 women) were included in the study. The average age of the patients was 40.7 ± 11.6 years (range, 18 to 64 years). The mean duration of follow-up was 26.4 ± 4.6 months (range, 24 to 40 months). Fracture healing was observed in 73 patients (94.8%).

DISCUSSION

The healing rate of type II odontoid fractures (with an age range of 18 to 64 years) treated with modern posterior atlantoaxial fixation is relatively high. For patients at that age range, posterior atlantoaxial temporary screw-rod fixation for type II odontoid fractures can be conducted with a low risk of nonunion.

LEVEL OF EVIDENCE

Level IV, therapeutic.

Surgical Management of Adult Traumatic Atlantoaxial Rotatory Subluxation with Unilateral Locked Facet; Case Report and Literature Review

Atlantoaxial rotatory subluxation (AARS) is rarely occurred in adults with trauma as the most common cause. In type A and B it is usually managed with close reduction and external brace; however, in nonresponsive cases, surgical interventions might be needed. Our patient is a 21-year-old man with neck pain and torticollis after a car turn- over. There was C1-C2 rotatory subluxation with left side locked facet and C1 rotation about 40 degrees relative to C2 on computed tomography without evident of ligamentous injury in magnetic resonance imaging (MRI). However, during the first 48 hours, two tries of close reduction using Gardner cervical traction under fluoroscopy were failed. Thus, the patient underwent open reduction of the subluxation and atlantoaxial fixation (Harm’s technique) with subsequent relief of pain and torticollis. This a rare case of traumatic AARS type A with unilateral locked facet joint in an adult patient which needed surgical manipulation for reduction. The management of the AARS in adults should be individualized in each patient.

Atlanto-axial rotatory fixation: a serious potential complication of paediatric ENT surgery that requires prompt diagnosis and treatment

BACKGROUND

Atlanto-axial rotatory fixation is a persistent deformity of the C1-2 vertebral relationship caused by subluxation of the articular surfaces, and can occur after positioning for ENT procedures where the head is rotated - for example to access the ear or posterior triangle of the neck. If promptly recognised, it can usually be managed successfully with conservative methods, without long-lasting sequelae, but delayed or inappropriate management may lead to permanent neck deformity, neurological problems and pain.

METHOD

Case review.

CASE REPORT

Two children with atlanto-axial rotatory fixation following ENT surgery; one child was referred early and managed successfully, and one had delayed referral resulting in permanent severe positional deformity.

CONCLUSION

Atlanto-axial rotatory fixation is easily missed; there are significant clinical and medicolegal implications if it is not promptly recognised. A suggested management algorithm is presented.

Is It Feasible to Treat Odontoid Fractures via Primary Posterior Reduction and Fixation without Fusion?

OBJECTIVE

To evaluate results and feasibility of primary posterior reduction and fixation without fusion using C1-C2 screw-rod system for odontoid fractures.

METHODS

This study comprised a consecutive series of 46 patients with odontoid fractures. Posterior reduction and fixation without fusion using the C1-C2 screw-rod system was performed, and instrumentation was not removed. Radiologic outcomes were assessed on follow-up computed tomography or plain radiographs. Visual analog scale of neck pain, American Spinal Injury Association impairment scale, patient satisfaction, neck disability index, and range of motion of flexion extension and rotation of the cervical spine were recorded and analyzed.

RESULTS

Mean follow-up time was 4.1 years (range, 12 months to 8 years). Radiographic evaluation indicated solid fusion of odontoid fractures in all cases and no implant failures. No patient reported severe neck pain at follow-up. Neurologicl evaluation showed there was 1- to 2-grade improvement in patients with neurologic deficit. Of patients, 31 reported acceptable outcomes, and 15 reported good outcomes. Range of motion of rotation of the cervical spine and neck disability index score gradually improved significantly during 1 year of follow-up with no obvious change after that. Rate of neck disability index score improvement was 85%.

CONCLUSIONS

Posterior reduction and fixation without fusion can be successfully performed for healing of odontoid fractures with acceptable results and minimal morbidity.

Atlantoaxial Rotatory Fixed Dislocation: Report on a Series of 32 Pediatric Cases

STUDY DESIGN

Retrospective case series of atlantoaxial rotatory fixed dislocation (AARFD).

OBJECTIVE

To describe clinical features and the surgical treatment of AARFD.

SUMMARY OF BACKGROUND DATA

The classification and treatment strategy for atlantoaxial rotatory fixation (AARF) were previously described and remained controversial. AARF concomitant with atlantoaxial dislocation has different clinical features and treatment strategy with the most AARF. Due to deficiency of the transverse ligament or odontoid, the atlantoaxial remains unstable even after the torticollis relieved or cured. Because of the rarity, treatment strategy for this special condition has not been specialized and fully explored in the literatures.

METHODS

Thirty-two children with AARFD (sustained torticollis more than 6 weeks and atlanto-dental internal more than 5 mm) were retrospectively reviewed. Treatment methodology, pearls, and pitfalls of the treatment were discussed.

RESULTS

Thirty-two cases had sustained torticollis for an average of 5.7 months. ADI of them ranged from 8 to 22 mm, with a mean of 11.3 mm. Eight cases presented with signs and symptoms of spinal cord dysfunction. All 32 cases underwent surgery and had no spinal cord or vertebral artery injury. The surgery included posterior reduction and fusion (reducible dislocation and torticollis, 16 cases), and transoral release followed by posterior reduction and fusion (irreducible dislocation and torticollis, 16 cases). The average follow-up time was 42 months. Solid fusion and torticollis healing were achieved in 31 patients (96.9%) as detected radiologically. Two cases (6.3%, 2/32) suffered complications (cerebrospinal fluid leakage and recurred torticollis followed by revision).

CONCLUSION

AARFD had distinct clinical features relative to common presentations of AARF. Because of deficiency of the transverse ligament or odontoid and subsequent atlantoaxial dislocation, surgical treatments are applied for this condition, including transoral release and posterior C1-2 reduction and fusion. AARFD cases were successfully managed surgically without preoperative traction, with few complications seen.

LEVEL OF EVIDENCE

4.

Allograft versus autograft for pediatric posterior cervical and occipito-cervical fusion: a systematic review of factors affecting fusion rates

OBJECT Fusion rates are high for children undergoing posterior cervical fusion (PCF) and occipito-cervical fusion (OCF). Autologous bone has been widely used as the graft material of choice, despite the risk of donor-site morbidity associated with harvesting the bone, possibly because very low fusion rates were reported with posterior allograft cervical fusions in children several decades ago. Higher overall fusion rates using allograft in adults, associated with improvements in internal fixation techniques and the availability of osteoinductive substances such as bone morphogenetic protein (BMP), have led to heightened enthusiasm for the use of bank bone during pediatric PCF. A systematic review was performed to study factors associated with successful bone fusion, including the type of bone graft used. METHODS The authors performed a comprehensive PubMed search of English-language articles pertaining to PCF and OCF in patients less than 18 years old. Of the 561 abstracts selected, 148 articles were reviewed, resulting in 60 articles that had sufficient detail to be included in the analysis. A meta-regression analysis was performed to determine if and how age, fusion technique, levels fused, fusion substrate, BMP use, postoperative bracing, and radiographic fusion criteria were related to the pooled prevalence estimates. A systematic review of the literature was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. RESULTS A total of 604 patients met the specific inclusion and exclusion criteria. The overall fusion rate was 93%, with a mean age of 9.3 years and mean follow-up of 38.7 months. A total of 539 patients had fusion with autograft (94% fusion rate) and 65 patients with allograft (80% fusion rate). Multivariate meta-regression analysis showed that higher fusion rates were associated with OCF compared with fusions that excluded the occiput (p < 0.001), with the use of autograft instead of allograft (p < 0.001), and with the use of CT to define fusion instead of plain radiography alone. The type of internal fixation, the use of BMP, patient age, and the duration of follow-up were not found to be associated with fusion rates in the multivariate analysis. CONCLUSIONS Fusion rates for PCF are high, with higher rates of fusion seen when autograft is used as the bone substrate and when the occiput is included in the fusion construct. Further study of the use of allograft as a viable alternative to autograft bone fusion is warranted because limited data are available regarding the use of allograft in combination with more rigid internal fixation techniques and osteoinductive substances, both of which may enhance fusion rates with allograft.

Direct diffusion-based parcellation of the human thalamus

To assess stable anatomical features of the human thalamus, an unbiased diffusion tensor parcellation approach was used to segment thalamic substructures with similar spatial orientation. We determined localization, size and individual variations of 21 thalamic clusters in a group of 63 healthy human subjects (32 males/31 females). The laterality differences accounted for ± 6% and gender differences for ± 4% of the thalamic volume. Consecutively, five stable clusters in the anterior, medial, lateral and posterior thalamus were selected, which were common to 90% of all subjects and contained at least 10 voxels. These clusters could be assigned to the anteroventral nucleus (AN) group, the mediodorsal (MD) nucleus, the medial pulvinar (PuM), and the lateral nuclei group. The subcortical and cortical connectivity of these clusters revealed that: (1) the oblique cranio-caudal-oriented fibers of the AN cluster mainly connect to limbic structures, (2) the numerous dorso-frontal-oriented fibers of MD mainly project to the prefrontal cortex and the medial temporal lobe, (3) the fibers of the PuM running in parallel with the x-axis project to medio-occipital and medio-temporal areas and connect visual areas with the hippocampus and amygdala and via intrathalamic pathways with medio-frontal areas, and (4) the oblique caudo-cranial fibers of the two lateral clusters located anteriorly in the motor and posteriorly in the sensory thalamus are routing sensory-motor information from the brain stem via the internal capsule to pre- and peri-central regions of the cortex.

Atlantoaxial rotatory subluxation in children

Atlantoaxial rotatory subluxation is a rare condition in which patients present with the acute onset of torticollis. Atlantoaxial rotatory subluxation represents a spectrum of disease from muscle spasm to a fixed mechanical block to reduction of the atlantoaxial complex. If left untreated, some cases may resolve spontaneously; however, other cases may result in the development of secondary changes in the bony anatomy of the atlantoaxial joint, leading to persistent deformity. Diagnosis of the condition is largely clinical but can be aided by various imaging modalities, including radiographs, dynamic CT scanning, three-dimensional CT reconstructions, or MRI. Consideration should always be given to infection or other inflammatory disease as an underlying, precipitating cause. Treatments include observation, the use a cervical collar and analgesics, halter or skeletal traction, and posterior fusion of C1-C2. The most important factor for success of conservative treatment is the time from the onset of symptoms to recognition and the initiation of treatment.

Posterior reduction and temporary fixation for odontoid fracture: a salvage maneuver to anterior screw fixation

STUDY DESIGN

A prospective study.

OBJECTIVE

To evaluate the outcomes of posterior reduction and temporary fixation using the C1-C2 screw-rod system for odontoid fracture unsuitable for anterior screw fixation.

SUMMARY OF BACKGROUND DATA

Anterior screw fixation has become the most widely used surgical procedure for the stabilization of odontoid fractures. However, if there is any contraindication for anterior fixation, posterior atlantoaxial fusion is preferred, eliminating the normal rotation of the atlantoaxial complex.

METHODS

A consecutive series of 22 patients with odontoid fracture unsuitable for anterior screw fixation were involved in this study. Posterior reduction and fixation without fusion using the C1-C2 screw-rod system was performed. Once fracture healing was obtained, instrumentation was removed. The visual analogue scale of neck pain, neck stiffness, American Spinal Injury Association impairment scale, patient satisfaction, and neck disability index were recorded. The range of motion of C1-C2 in flexion-extension and rotation was calculated.

RESULTS

The average age at internal fixation surgery was 40.2±11.3 years. The mean duration of follow-up was 41.8±26.8 months. There were no complications associated with instrumentation. All patients returned to their preoperative work. Fracture healing was observed in 21 patients and the instrumentation was removed. After removing the instrumentation, the visual analogue scale was reduced and neck stiffness were relieved (all P<0.01). Patient satisfaction and neck disability index had improved (all P<0.01). The range of motion of C1-C2 returned to 4.75°±1.62° and 25.70°±5.51° in flexion-extension and in rotation, respectively. No osteoarthritis was observed at the C1-C2 lateral mass joints.

CONCLUSION

Posterior reduction and temporary fixation using the C1-C2 screw-rod system was an optimal salvage maneuver to anterior screw fixation for odontoid fracture. It could effectively avoid the motion loss of C1-C2 caused by posterior atlantoaxial fusion.

LEVEL OF EVIDENCE

3.

A morphologically atypical case of atlantoaxial rotatory subluxation

A rare case of atlantoaxial rotatory subluxation occurred after pediatric cervical spine surgery performed to remove a dumbbell-shaped meningioma at the level of the C1/C2 vertebrae. This case is classified as a post-surgical atlantoaxial rotatory subluxation, but has a very rare morphology that has not previously been reported. Although there are several reports about post-surgical atlantoaxial rotatory subluxation, an important point of this case is that it might be directly related to the spinal cord surgery in C1/C2 level. On day 6 after surgery, the patient presented with the Cock Robin position, and a computed tomography scan revealed a normal type of atlantoaxial rotatory subluxation. Manual reduction was performed followed by external fixation with a neck collar. About 7 months after the first surgery, the subluxation became severe, irreducible, and assumed an atypical form where the anterior tubercle of C1 migrated to a cranial position, and the posterior tubercle of C1 and the occipital bone leaned in a caudal direction. The pathogenic process suggested deformity of the occipital condyle and bilateral C2 superior facets with atlantooccipital subluxation. A second operation for reduction and fixation was performed, and the subluxation was stabilized by posterior fixation. We encountered an unusual case of a refractory subluxation that was associated with an atypical deformity of the upper spine. The case was successfully managed by posterior fixation.

Direct visualization of anatomic subfields within the superior aspect of the human lateral thalamus by MRI at 7T

BACKGROUND AND PURPOSE

The morphology of the human thalamus shows high interindividual variability. Therefore, direct visualization of landmarks within the thalamus is essential for an improved definition of electrode positions for deep brain stimulation. The aim of this study was to provide anatomic detail in the thalamus by using inversion recovery TSE imaging at 7T.

MATERIALS AND METHODS

The MR imaging protocol was optimized on 1 healthy subject to segment thalamic nuclei from one another. Final images, acquired with 0.5(2)-mm2 in-plane resolution and 3-mm section thickness, were compared with stereotactic brain atlases to assign visualized details to known anatomy. The robustness of the visualization of thalamic nuclei was assessed with 4 healthy subjects at lower image resolution.

RESULTS

Thalamic subfields were successfully delineated in the dorsal aspect of the lateral thalamus. T1-weighting was essential. MR images had an appearance very similar to that of myelin-stained sections seen in brain atlases. Visualized intrathalamic structures were, among others, the lamella medialis, the external medullary lamina, the reticulatum thalami, the nucleus centre médian, the boundary between the nuclei dorso-oralis internus and externus, and the boundary between the nuclei dorso-oralis internus and zentrolateralis intermedius internus.

CONCLUSIONS

Inversion recovery-prepared TSE imaging at 7T has a high potential to reveal fine anatomic detail in the thalamus, which may be helpful in enhancing the planning of stereotactic neurosurgery in the future.

Not your typical torticollis: a case of atlantoaxial rotatory subluxation

A 9-year-old boy was pushed while carrying a heavy backpack. He had no fall or direct trauma to his neck. After a few hours from the incident, he presented with neck pain and torticollis. However, somewhat atypical for torticollis, he was not able to rotate his face to the neutral position. There were no neurological deficits. Concerned by his inability to rotate his neck, the clinician suggested CT of the upper cervical spine, which demonstrated rotary subluxation of the atlantoaxial junction. The patient was taken to the operating theatre. Reduction was performed under general anaesthesia. He did well and was back to school in the following days.

Imaging of the craniovertebral junction anomalies in children

The craniovertebral junction (CVJ) is interposed between the unsegmented skull and the segmented spine; it is functionally unique as it allows the complex motion of the head. Because of its unique anatomy, numerous craniometric indices have been devised. Because of its complex embryology, different from that of the adjacent skull and spine, it is commonly the seat of malformations. Because of the mobility of the head, and its relative weight, the craniovertebral junction is vulnerable to trauma. Like the rest of the axial skeleton, it may be affected by many varieties of dysplasia. In addition, the bony craniovertebral junction contains the neural craniovertebral junction and its surrounding CSF: any bony instability or loss of the normal anatomic relationships may therefore compromise the neural axis. In addition, the obstruction of the meningeal spaces at this level can compromise the normal dynamics of the CSF and result in hydrocephalus and/or syringohydromyelia. To image the CVJ, plain X-rays are essentially useless. MR is optimal in depicting the soft tissues (including the neural axis) and the joints, as well as the bone itself. CT still may be important to better demonstrate the bony abnormalities.

Atlanto axial rotatory dislocation in adults: a rare complication of an epileptic seizure--case report

Atlanto Axial Rotatory Dislocations (AARDs) are a heterogeneous group of post-traumatic pathologies typical of the pediatric age, and rare in adults. We describe the case of a 34-year-old woman, developing Atlanto Axial Rotatory Fixation (AARF) after a generalized tonic-clonic epileptic seizure, an extremely rare traumatic cause never described in literature. AARF was detected only 1 month after the accident and nonsurgical treatment was attempted at the beginning. The patient underwent surgery only 2 months after the accident. The best treatment should be conservative reduction within 1 month; when it is not possible, it is advisable to perform surgery as soon as possible. C1-C2 fixation with Harm's technique is the gold standard for fixed luxations. Delay of treatment makes intraoperative reduction more difficult and increase the establishment of the chronic permanent change of neck muscles and ligaments.

Trauma of the upper cervical spine: focus on vertical atlantoaxial dislocation

PURPOSE

Traumatic ligament injuries of the craniovertebral junction, either isolated or associated with bone avulsion or fracture, often lead to death. These injuries are rare and underrated but are increasingly seen in emergency departments due to the improvement in initial on-scene management of accidents. Vertical atlantoaxial dislocation (AAD) is a specific lesion that was barely reported. Based on our experience, our goal was to systematically investigate the prevalence and prognosis of traumatic vertical AAD and discuss its management.

METHODS

All cervical CT scans performed at our institution between 2006 and 2010 for cervical trauma in adults were retrospectively reviewed. Based on the measurement of lateral mass index (LMI), defined as the gap between C1 and C2 articular facets, we identified three cases of traumatic vertical AAD in 300 CT scans. Their medical records were investigated.

RESULTS

The incidence of vertical AAD was 1% in the exposed population. One case was an isolated vertical AAD and two were associated with a type II odontoid fracture. We report the first case in the literature of unilateral vertical AAD. Two patients died rapidly; the survivor was treated with occipitocervical fixation. Specific maneuvers were used for immobilization and reduction.

CONCLUSIONS

This study found a not insignificant incidence of vertical AAD and a high lethality rate. LMI appears to be a relevant radiological criterion for this diagnosis, for which traction is contraindicated. Associated neurological or vascular damage should be suspected and investigated. In our experience, spinal surgical fixation is required because of major instability.

Atlantoaxial rotatory fixation--a cause of torticollis

BACKGROUND

A rare, but important cause of torticollis in children is atlantoaxial rotatory fixation. If the patient remains undiagnosed for more than three months, surgery is generally the only therapeutic alternative. In this article we present our experiences of surgical treatment of late-diagnosed atlantoaxial rotatory fixation in children.

MATERIAL AND METHOD

This article is based on a review of the case notes of patients who underwent surgery for atlantoaxial rotatory fixation in the Department for Neurosurgery at Oslo University Hospital, Rikshospitalet, during the period 2004-10.

RESULTS

The material sample consists of six children aged from seven to 14 years. Five had suffered minor trauma to the upper neck region, while one had had an upper respiratory tract infection. The diagnosis was made 5-36 months after the onset of symptoms. In three of the patients, an attempt was made at closed reduction without success. A CT scan one year postoperatively showed a normal position of the atlantoaxial joint in two patients and partial reduction in three. In the sixth patient there was bone fusion at the time of the operation, and open reduction was unsuccessful. All six patients had reduced rotational movement of the neck at the one-year check-up.

INTERPRETATION

All our patients were diagnosed more than five months after the onset of symptoms. Full or partial reduction was achieved in five of the six.

Optimized 3D magnetization-prepared rapid acquisition of gradient echo: identification of thalamus substructures at 3T

BACKGROUND AND PURPOSE

Because the substructures of the thalamus are not visible on standard T1- and T2-weighted MR images, planning of deep brain stimulation implantation relies on stereotactic atlas coordinates. The goal of the present work was to test whether an optimized 3D MPRAGE protocol can depict thalamus substructures.

MATERIALS AND METHODS

After optimization of the TI to maximize contrast between gray matter and white matter, 6 healthy subjects were scanned at 3T with the optimized 3D MPRAGE. The results were compared with stereotactic atlases, and 2 expert readers trained in thalamic anatomy identified the 4 large thalamic nuclei groups.

RESULTS

There was a high agreement between the different atlases and the resulting MR images. The 4 large thalamic nuclei groups (anterior, lateral, medial, posterior) could be detected reliably. The inter-reader consistency on the size and location was 75%-92%.

CONCLUSIONS

The optimized 3D MPRAGE protocol improves contrast in the thalamus, and the 4 large thalamic nuclei groups can be identified with high inter-reader agreement.

Novel technique of reduction of a chronic atlantoaxial rotatory fixation using a temporary transverse transatlantal rod

BACKGROUND CONTEXT

Chronic atlantoaxial rotatory fixation (AARF) is uncommon as acute AARF is easily reduced either spontaneously or by conservative methods. Various anterior and posterior surgical approaches for a chronic AARF have been reported because of the difficulty encountered in obtaining reduction.

PURPOSE

To describe a novel technique of reduction of a chronic AARF using a temporary transverse transatlantal rod.

STUDY DESIGN

Technical report.

METHODS

A 13-year-old girl presented with an 8-month-old chronic AARF with typical torticollis and "cock-robin" posture of the head with a normal neurology. As closed reduction with skull traction for 2 weeks failed to reduce the deformity, the patient underwent C1-C2 fusion. C1 lateral mass and C2 pedicle screws were inserted under computer navigation. A temporary transverse rod across the atlas and axis was placed to secure a three-column fixation to derotate the subluxed atlas into anatomical alignment. Rods were then connected between the C1 lateral masses and the C2 pedicle screws and fusion obtained with autologous iliac crest grafts.

RESULT

Anatomic reduction of the atlantoaxial region was obtained without neural compromise, and satisfactory fusion was observed at 6-months follow-up.

CONCLUSION

A temporary transatlantal rod provides a secure anchor point for easy maneuverability for reduction of a chronic AARF and has the advantage of being used even in the absence of the posterior arch of the atlas.