Atlanto-occipital Instability Research Articles

Biomechanical Study of Atlanto-occipital Instability in Type II Basilar Invagination: A Finite Element Analysis.

Recent studies indicate that 3 morphological types of atlanto-occipital joint (AOJ) exist in the craniovertebral junction and are associated with type II basilar invagination (BI) and atlanto-occipital instability. However, the actual biomechanical effects remain unclear. This study aims to investigate biomechanical differences among AOJ types I, II, and III, and provide further evidence of atlanto-occipital instability in type II BI. Models of bilateral AOJ containing various AOJ types were created, including I-I, I-II, II-II, II-III, and III-III models, with increasing AOJ dysplasia across models. Then, 1.5 Nm torque simulated cervical motions. The range of motion (ROM), ligament and joint stress, and basion-dental interval (BDI) were analyzed. The C0-1 ROM and accompanying rotational ROM increased progressively from model I-I to model III-III, with the ROM of model III-III showing increases between 27.3% and 123.8% indicating ultra-mobility and instability. In contrast, the C1-2 ROM changes were minimal. Meanwhile, the stress distribution pattern was disrupted; in particular, the C1 superior facet stress was concentrated centrally and decreased substantially across the models. The stress on the C0-1 capsule ligament decreased during cervical flexion and increased during bending and rotating loading. In addition, BDI gradually decreased across the models. Further analysis revealed that the dens showed an increase of 110.1% superiorly and 11.4% posteriorly, indicating an increased risk of spinal cord impingement. Progressive AOJ incongruity critically disrupts supportive tissue loading, enabling incremental atlanto-occipital instability. AOJ dysplasia plays a key biomechanical role in the pathogenesis of type II BI.

Predicting the Need for Occipitocervical Fusion for Patients with Lower Clival Chordoma: A Single-Center Retrospective Study

To assess the impact of tumor extension into the occipital condyle (OC) in lower clival chordoma management and the need for occipito-cervical fusion (OCF). A retrospective analysis was conducted on 35 patients with lower clival chordoma. The preoperative area of the intact OCs, Hounsfield units, and the integrity of the apical ligament and the tectorial membrane were assessed using preoperative imaging. Seven (20%) patients were in the OCF group. The OCF group exhibited a higher prevalence of preoperative pain in the neck or head (p = 0.006), ligament absence (p = 0.022), and increased propensity for postoperative wound issues (p = 0.022) than the non-OCF group. The OCF group had less intact OCs (p < 0.001) and higher spinal instability neoplastic score (p = 0.002) than the non-OCF group. All patients with intact OCs<60% underwent OCF, and those with OCs≥70% were treated without OCF. Those with OCs between 60% and 69% underwent OCF if the ligaments were eroded, and did not undergo OCF if the ligaments were intact. Treatment strategies varied, with endoscopic endonasal approach (EEA) alone being common. Radiation therapy was administered to 89% of patients. All three patients treated with OCF after tumor resection had wound issues; none treated with OCF before resection had wound issues. None developed atlanto-occipital instability. Survival rates did not significantly differ between groups. In the absence of mobility-related neck pain, patients with lower clival chordoma and intact OC≥60%, intact apical ligament, and intact tectorial membrane, may not require OCF.

Brain and craniovertebral junction in patients with achondroplasia using low dose dynamic computed tomography

Purpose: To describe the brain and craniovertebral junction (CVJ) in achondroplasia by dynamic low dose computed tomography (CT). Methods: This paper documents a cross-sectional retrospective study performed between 1998 and 2013. The Ethics and Research Committee approved the project. The investigators reviewed the medical records of 440 patients with skeletal dysplasia and performed flexion-extension CT for 24 patients with achondroplasia confirmed by molecular testing. They were divided in two groups: children younger than eight years old and group 2 with older individuals. Normal scans were selected as controls in proportion 1:4. Three measurements were made by two radiologists using the following parameters: Evans Ratio, cerebroventricular index of the anterior horns and maximum width of the third ventricle; diameters of the foramen magnum (FM), width of the spinal canal, clivus size, basion-axial interval, atlantooccipital interval and Powers ratio, atlantodental interval, distance of the dens tip position above McGregor line and Welcher angle. T-test, Kruskal-Wallis and Fisher statistics were used. P-value&lt;0.05 threshold was considered for statistical significance. Results: The ventricles were greater, and the FM was smaller in achondroplastic patients than in controls scans (p&lt;0.01). Other findings were: ventriculomegaly (30%), hydrocephalus (4%), narrowing of FM (between 96% and 100%), spinal stenosis (92%), clivus hypoplasia (88%), atlantooccipital instability (25%), atlantoaxial instability (13 %), basilar invagination (13%) and platybasia (8%). There was no upper cervical compressive myelopathy. There was no difference of CVJ changes between the groups 1 and 2 (p&gt;0.09). Conclusion: The craniometry showed the most frequent cerebral and CVJ changes in achondroplasia.

Congenital atlanto-occipital dislocation in a patient with Down syndrome: a case report

Down syndrome, also known as trisomy 21, is associated with congenital cervical spine abnormalities, including atlantoaxial instability with or without os odontoideum, atlanto-occipital instability, and hypoplasia of the atlas. Herein, we report a case of Down syndrome complicated by congenital atlanto-occipital dislocation. The patient presented with severe cervical myelopathy at 13 years of age after a 10-year follow-up. Radiography and computed tomography revealed os odontoideum protruding into the foramen magnum and congenital anterior atlanto-occipital dislocation. Additionally, a bifurcated internal occipital crest with a thinned central portion of the occipital bone was noted. Magnetic resonance imaging revealed kyphotic alignment of the spinal cord with severe compression at the foramen magnum level. As the neurological impairment was partially improved by halo vest immobilization, we performed in situ O-C2 fusion with an iliac autograft and decompression of the foramen magnum and posterior arch of C1. An improvement was observed immediately after surgery. Two years after surgery, radiography and computed tomography showed solid O-C2 segment fusion. The accumulation of similar cases is essential for determining the prognosis or optimal treatment for this rare congenital condition.

Exploring the Pathogenesis of Atlanto-Occipital Instability in Chiari Malformation With Type II Basilar Invagination: A Systematic Morphological Study

Our previous study suggested that atlanto-occipital instability (AOI) is common in patients with type II basilar invagination (II-BI). To further understand the pathogenesis of AOI in Chiari malformations (CM) and CM + II-BI through systematic measurements of the bone structure surrounding the craniocervical junction. Computed tomography data from 185 adults (80 controls, 63 CM, and 42 CM + II-BI) were collected, and geometric models were established for parameter measurement. Canonical correlation analysis was used to evaluate the morphological and positional relationships of the atlanto-occipital joint (AOJ). Among the 3 groups, the length and height of the condyle and superior portion of the lateral masses of the atlas (C1-LM) were smallest in CM + II-BI cases; the AOJ had the shallowest depth and the lowest curvature in the same group. AOJs were divided into 3 morphological types: type I, the typical ball-and-socket joint, mainly in the control group (100%); type II, the shallower joint, mainly in the CM group (92.9%); and type III, the abnormal flat-tilt joint, mainly in the CM + II-BI group (89.3%). Kinematic computed tomography revealed AOI in all III-AOJs (100%) and some II-AOJs (1.5%) but not in type I-AOJs (0%). Morphological parameters of the superior portion of C1-LM positively correlated with those of C0 and the clivus and significantly correlated with AOI. Dysplasia of the condyle and superior portion of C1-LM exists in both CM and II-BI cases yet is more obvious in type II-BI. Unstable movement caused by AOJ deformation is another pathogenic factor in patients with CM + II-BI.

Awake fiberoptic intubation in a pediatric patient with cervical spine injuries on a halo-vest: a case report

Awake fiberoptic intubation (AFOI) in pediatric patients remains a continuous challenge for the anesthetists, and is considered more cumbersome a procedure as compared to the adult population. The coexistence of unstable cervical spine injuries, although rare, but complicates the procedure even more. Proper pre-planning, adequate sedation and analgesia and the patient’s conscious cooperation are needed to ensure success. We describe a step-by-step approach to a successful AFOI in a 12-year-old child who had atlantooccipital instability and had a halo-vest on. Titrated dose of sedation and analgesia, obtunding airway reflex and patient’s cooperation is a key to successful AFOI in this patient.&#x0D; Abbreviations: AFIO: Awake fiberoptic intubation; OMF: Oromaxillofacial; BMI: body mass index; TCI: Target-controlled infusion&#x0D; Key words: Airway Management; Airway Obstruction / complications; Anesthesia / methods; Child; Dexmedetomidine, Intravenous infusion; Fiber Optic Technology; Intubation, Intratracheal / methods; Laryngoscopes; Pediatric&#x0D; Citation: Hassan MH. Awake fiberoptic intubation in a pediatric patient with cervical spine injuries on a halo-vest: a case report. Anaesth. pain intensive care 2022;26(4):569-573; DOI: 10.35975/apic.v26i4.1968&#x0D; Received: April 30, 2022; Reviewed: May 01, 2022; Accepted: June 28, 2022

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

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. 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. 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. 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.

The Association Between Radiographic and MRI Cervical Spine Parameters in Patients With Down Syndrome

IntroductionMany patients with Down syndrome (DS) develop upper cervical spine instability that may lead to spinal cord injury. The purpose of this study was to investigate the association between the spinal cord compression in MRI and the occipto-cervical instability evident on plain radiographs in a Japanese population.MethodsA retrospective analysis of cervical spine radiographs and MRI acquired from patients with DS was performed. Radiographic evaluation included measuring the atlanto-dental interval (ADI) and space available for the cord. The basion axial interval (BAI) and Weisel-Rothman (WR) measurements were taken to quantify occipto-axial (OA) and atlanto-occipital (AO) instability. These parameters were collected in patients both with (positive) and without (negative) spinal cord compression evident on MR imaging in a neutral position and the values were compared. In addition, we investigated the association between spinal cord compression and previously defined abnormal values with logistic regression analysis (abnormal values: ADI>6mm, SAC<14mm, BAI<-12mm or >5mm in neutral position).ResultsThere were 17 patients in the positive group and 52 patients in the negative group. WR was 7.4 mm±6.0 in positive group and 8.6 mm±4.8 in negative group (p=0.31) in neutral position, 3.9 mm±5.4 and 6.3±5.0 (p=0.06) in flexion, and 7.0 mm±6.8 and 7.2 mm±4.8 (p=0.75) in extension, respectively. The difference in WR between flexion and extension was 3.1 mm ± 4.6 and 0.9 mm ± 3.8, respectively (p=0.15). All other parameters showed significant differences between the two groups excluding BAI in extension (p<0.05). In addition, abnormal values that significantly correlated with cord compression were ADI (odds ratio 42.3 p<0.01 95% CI 4.16-430.0) and SAC (odds ratio 31.90 p=0.013 95% CI 2.06-494.0).ConclusionsThese data suggest that OA and AA instability measured with ADI, SAC, and BAI are significantly associated with spinal cord compression in MRI; whereas instability measured with WR and DWR is not. In addition, the previously defined abnormal thresholds for the ADI and SAC can be used for screening the Japanese population.

Treatment of a Displaced Occipital Condyle Fracture - A Case to be discussed

Before the advent of computed tomography, occipital condyle injuries were solely a postmortem diagnosis. Nowadays, CT is well established in the diagnostic workflow of trauma management, allowing accurate planning and proper treatment. Anderson and Montesano as well Tuli developed radiologic classifications, each based on a small number of cases, in regards to the stability of the lesion and also provided treatment recommendations. In this case study we present a 24-year-old man suffering massive trauma to the head and thorax from a agricultural vehicle accident, leading to a displaced avulsion fracture of the right occipital condyle with high atlanto-occipital instability (Anderson Montesano type III). However, the patient did not develop any neurological deficit. Within the scope of the damage control polytrauma algorithm, the atlanto-occipital instability was initially stabilized in a HALO fixator. For devinitive treatment, we decided on an internal occipito-cervical fixation with a permanent fusion of the injured C0/C1-segment without reduction of the dislocated fragment at a time 14 days after the accident. The fixation construct spanned from the occiput to C3 in order to achieve a high primary stability. At 3-months follow-up, CT scans showed bony healing of the right condyle in an unchanged displaced position and a successful posterior fusion of C0/C1. After one year, a complete implant removal was done.

Rod and Screw Fixation for Cranio-Cervical Instability

Background Data: Atlanto-occipital dislocation is a rare and fatal condition. Pain, limitation of movements, and weakness, were the main complaints of patients with upper cervical lesions. Internal fixation and fusion was indicated in all patients of Atlanto occipital dislocation with deficits. CT scan is the imaging modality of choice for evaluation. Objective: To evaluate the efficacy and safety of rod and screw fixation in cranio-cervical instability. Study Design: Retrospective study reviewed all patient treated by rod and screw fixation, they were 12 patient operated for atlanto-occipital instability from April 2013 to April 2016 in Alazher University Hospital Damietta. Pre and postoperative data collection and analysis of the outcome were completed based on the Frankel classification and grading. Patients and Methods: We operated 12 patients, 10 with traumatic and 2 with pathologically diagnosed Atlanto occipital instability. From April 2013 to April 2016. All patients presented with neck pain, limitation of neck movement, and neurological deficits. The patients were investigated by standard plain X ray to the cervical spine, CT scan and MRI of the cervical spine pre-operatively, and they operated thorough posterior Cranio-cervical fixation. These patients followed post-operatively clinically for improving neural functions and radiologically for alignment, stability, fusion and efficacy of hard ware fixation. Results: The mean age of the studied cases was 42.1 years, trauma was the cause of instability in 10 patients, and 2 patients one with rheumatoid arthritis and one with neoplastic lesion. The mean follows up period is 14.7 months. We used screw rod system in posterior craniocervical fixation with iliac bone graft without operative or post-operative complications. All our patients were improved neurologically post-operatively and no hardware failure during the follow up period. Conclusion: Craniocervical instability was rare condition, with miss diagnosis and may be fatal condition. Posterior occipitocervical fixation when indicated can be done by various techniques. The screw rod system was the most upgraded used technique with immediate rigid fixation. Surgery in this area was possible with confident results.

Part 1: CBCT EVALUATION OF ATLANTOAXIAL/ATLANTO-OCCIPITAL JOINTS FOR CERVICAL INSTABILITY RISK ASSESSMENT

Background In dental radiography, the vertical atlantoaxial index (VAAI)1 measures the vertical relationship of the atlas and the axis. Based on prior studies, value less than 0.8 might present a predisposition toward cervical instability. The Powers ratio (PR) is the ratio between the distance of 2 lines: (B–P): from basion to posterior arch of C1 (O–A): from opisthion to the anterior arch of atlas. The normal ratio is 1:1, if the ratio exceeds 1, it indicates atlanto-occipital instability. The basion–axial interval (BAI) is the horizontal distance between basion and posterior dens.4 The basion–dens interval (BDI) is the distance between the basion and the tip of the dens.4 Objective The objective of this study was to determine the potential risk for atlantoaxial/atlanto-occipital instability2 in patients who underwent cone beam computed tomography (CBCT) imaging of the head. The research was conducted at the Oral and Maxillofacial Radiology clinic of the University of Pennsylvania School of Dental Medicine (Philadelphia, PA). Materials and Methods After institutional review board approval, a preliminary study was performed on patients undergoing either preimplantation assessment of jaws or evaluation of atypical facial pain, and measurements were recorded. A total of 50 CBCT volumes were identified for the selected craniocervical cephalometric measurements. Analysis of the CBCT volumes and cephalometry were performed to record various craniocervical measurements and determine the potential risk of atlantoaxial atlanto-occipital instability. The measurements were done by using the midsagittal-view CBCT images. These measurements included BAI, BDI, VAAI, and PR. It was anticipated that these measurements would provide a risk estimate for cervical instability that could potentially result in spinal cord injury. All CBCT volumes were acquired by using the Carestream CS9300 machine (Carestream, Atlanta, GA). Results Based on the preliminary results, the average VAAI measurement was 0.7626, the average BAI was 4.970 mm, the average BDI was 5.043 mm, and the average PR was 0.6961. Discussion Apart from VAAI, BDI, and BAI, the PR3 was utilized in this study to find out the atlantoaxial dissociation (normal PR = 1:1). A ratio over 1 indicates atlanto-occipital dissociation (AOD. BAI is the horizontal distance between basion and the posterior cortex of the axis (normal ≤12 mm). BDI is the distance between the basion and the tip of the dens (normal ≤8.5 mm). Both BAI and BDI are used to diagnose AOD injuries.

Giant, Recurrent Atypical Pituitary Adenoma Presenting with Atlanto-occipital Instability

Giant, Recurrent Atypical Pituitary Adenoma Presenting with Atlanto-occipital Instability

Morphometric Study of Human Adult Occipital Condyle, Hypoglossal Canal and Foramen Magnum in Dry Skull of Modern Egyptians

The present study investigated analyze some morphometric data about occipital condyles (OCs), hypoglossal canals (HCs) and foramen magnum (FM) for safety transcondylar surgical approach, and to compare the Egyptian skull measurements with that of the other races. A total of 75 dry skulls of unknown sex which were randomly chosen from the archives of Department of Human Anatomy and Embryology, Faculty of Medicine, Suez Canal University were used with exclusion of the extremely deformed or damaged. The parameters were measured by digital Vernier calipers with 0.01 mm precision and a protractor. Statistical analysis of data - one way analysis of variance- was done using unpaired Student's t-test. Results indicated no statistical significant differences between the right and left sides of measured parameters. The morphometric analysis of the OC established that mean width & length was larger (14.8 & 22.9 mm) in Egyptian population when compared to other races. According to the parameters of the HCs, the mean length of right and left ones were 11.84 mm and 11.8 mm respectively, while their mean angles with the sagittal plane were found to be 31.8° and 31.6° respectively. The mean diameter of the intracranial end of the right HC was 6.24 mm and of the left one was 6.04 mm, on the other hand, the mean diameters of the extracranial ends were 6.18 mm and 6.04 mm respectively. Regarding the parameters of FM, the mean length and width were 35 mm and 29.4 mm respectively. On the other hand, the mean distance of right mastoid process to the nearest point of FM was 34.72 mm, while the left one located at a mean distance of 35.2 mm from FM. 40% of skulls studied exhibited an ovoid foramen magnum as the foramen magnum index was > 1.2 but 60% of our samples were ˂ 1.2 which were asymmetrical in shape. We conclude that careful radiological analysis of the craniocervical junction is required before surgery to prevent inadvertent complications such as hemorrhage, atlantooccipital instability and injury to major structures passing through foramen magnum. Our outcomes will be useful for safe surgery in craniocervical region in Egypt.

Spinal movement and dural sac compression during airway management in a cadaveric model with atlanto-occipital instability.

To analyze the compression of the dural sac and the cervical spinal movement during performing different airway interventions in case of atlanto-occipital dislocation. In six fresh cadavers, atlanto-occipital dislocation was performed by distracting the opened atlanto-occipital joint capsule and sectioning the tectorial membrane. Airway management was done using three airway devices (direct laryngoscopy, video laryngoscopy, and insertion of a laryngeal tube). The change of dural sac's width and intervertebral angulation in stable and unstable atlanto-occipital conditions were recorded by video fluoroscopy with myelography. Three-dimensional overall movement of cervical spine was measured in a wireless human motion track system. Compared with a mean dural sac compression of -0.5mm (-0.7 to -0.3mm) in stable condition, direct laryngoscopy caused an increased dural sac compression of -1.6mm (-1.9 to -0.6mm, p=0.028) in the unstable atlanto-occipital condition. No increased compression on dural sac was found using video laryngoscopy or the laryngeal tube. Moreover, direct laryngoscopy caused greater overall extension and rotation of cervical spine than laryngeal tube insertion in both stable and unstable conditions. Among three procedures, the insertion of a laryngeal tube took the shortest time. In case of atlanto-occipital dislocation, intubation using direct laryngoscopy exacerbates dural sac compression and may cause damage to the spinal cord.

C1 fractures: a review of diagnoses, management options, and outcomes.

The atlas is subject to fracture under axial load, often due to traumatic injuries such as shallow dives and automobile accidents. These fractures account for 2-13% of injuries to the cervical spine [Marcon RM et al. Clinics (Sao Paulo) 68(11):1455-61, 2013]. Fractures of the C1 vertebra are often difficult to diagnose, as there is often no neurological deficit or easily identifiable findings on radiographs. However, injuries to the atlas can be associated with vertebral artery injury and atlantoaxial or atlanto-occipital instability, making prompt and accurate diagnosis imperative. A detailed understanding of the anatomy, inherent stability, and common injury patterns is essential for any surgeon treating spinal trauma. This chapter explores the diagnosis and management of C1 fractures, as well as outcomes after treatment.

Morphometric analyses of atlas vertebrae-A cross sectional study

Introduction: Knowledge about morphometric measurements related to atlas vertebra are important for neurologists, neurosurgeons and head and neck surgeons who deal with traumatic or non-traumatic conditions which may lead to altanto-axial and atlanto- occipital instability. The aim of the present study was to assess the various parameters on the atlas vertebra which can help to determine the safe sites for the different surgical approaches. Materials and Methods: Study was carried out on 50 dry south Indian adult human atlas vertebrae of unknown sex which were collected from the department of anatomy. Eleven parameters were measured for each atlas using a digital vernier caliper. Results: Range, mean and standard deviations were measured and recorded and bilateral symmetry was observed. Conclusion: The parameters measured in the present study may help surgeons in avoiding and reducing complications such as vertebral artery injury, spinal cord injury during the surgical corrections of atlanto axial or atlanto occipital instability. Keywords: Atlas, vertebrae, Atlanto-axial, Atlanto-occipital, Interlaminar clamps

New Radiographic Index for Occipito-Cervical Instability.

Study DesignRetrospective study.PurposeTo propose a new radiographic index for occipito-cervical instability.Overview of LiteratureSymptomatic atlanto-occipital instability requires the fusion of the atlanto-occipital joint. However, measurements of occipito-cervical translation using the Wiesel-Rothman technique, Power's ratio, and basion-axial interval are unreliable because the radiologic landmarks in the occipito-cervical junction lack clarity in radiography.MethodsOne hundred four asymptomatic subjects were evaluated with lateral cervical radiographs in neutral, flexion and extension. They were stratified by age and included 52 young (20–29 years) and 52 middle-aged adults (50–59 years). The four radiographic reference points were posterior edge of hard palate (hard palate), posteroinferior corner of the most posterior upper molar tooth (molar), posteroinferior corner of the C1 anterior ring (posterior C1), and posteroinferior corner of the C2 vertebral body (posterior C2). The distance from posterior C1 and posterior C2 to the above anatomical landmarks was measured to calculate the range of motion (ROM) on dynamic radiographs. To determine the difference between the two age groups, unpaired t-tests were used. The statistical significance level was set at p<0.05.ResultsThe ROM was 4.8±7.3 mm between the hard palate and the posterior C1, 9.9±10.2 mm between the hard palate and the posterior C2, 1.7±7.2 mm between the molar to the posterior C1, and 10.4±12.1 mm between the molar to the posterior C2. There was no statistically significant difference for the ROM between the young- and the middle-aged groups. The intra-observer reliability for new radiographic index was good. The inter-observer reliability for the ROM measured by the hard palate was low, but was better than that by the molar.ConclusionsROM measured by the hard palate might be a useful new radiographic index in cases of occipito-cervical instability.

Atlanto-occipital Instability Following Endoscopic Endonasal Approach for Lower Clival Lesions: Experience With 212 Cases.

The endoscopic endonasal approach (EEA) for craniocervical lesions involving the lower clivus and occipital condyles carries an unclear risk of atlanto-occipital (AO) instability requiring arthrodesis. Elucidate risk factors for AO instability following EEA for clival lesions. We reviewed patients with clival tumors who underwent EEA at our institution between 2002 and 2012. Resection of the lower clivus, foramen magnum, AO joint, and occipital condyles were evaluated on fine-cut postoperative computed tomography. Two hundred twelve patients (mean age 47.9 years, 57.1% male) underwent transclival EEA for lower clival lesions. In addition to the lower clivus, resection involved the condyle in 14.2% of patients, the foramen magnum in 16.5%, and the AO joint in 1.4%. Quantification of condyle resection revealed complete resection in 3 cases, 75% resection in 8 cases, 50% resection in 6 cases, and 25% resection in 13 cases. Seven of these patients had EEA combined with an open, far-lateral approach. In total, 7 patients required arthrodesis following EEA (3.3%), 4 of them after a combined approach. All patients who underwent arthrodesis had primary bone tumors such as chordoma, chondrosarcoma, or osteosarcoma (P = .022). Degree of condyle resection was a significant factor predisposing to occipitocervical instability (P = .001 and P < .001 for 75% and 100% condyle resection, respectively). Use of a combined approach was significantly associated with arthrodesis (P < .001). EEA resection of the occipital condyles that results in greater than 75% condyle resection or EEA in combination with an open approach significantly increases the risk of AO instability and likely necessitates AO fixation. AO, atlanto-occipitalEEA, endoscopic endonasal approachOC, occipitocervical.

Skeletal dysplasia, global developmental delay, and multiple congenital anomalies in a 5‐year‐old boy—Report of the second family with B3GAT3 mutation and expansion of the phenotype

As a major component of the extracellular matrix, proteoglycans influence the mechanical properties of connective tissue and play an important role in cell-cell and cell-matrix interactions. Genetic defects of proteoglycan biosynthesis lead to multi-system disorders, often most prominently affecting the skeletal system and skin. Specific deficiencies in the enzymes involved in the biosynthesis of the linkage region between the core of the proteoglycan protein and its glycosaminoglycan side chains are known as linkeropathies. We report on a patient from a second family with a homozygous c.830G>A (p.Arg277Gln) mutation in the B3GAT3 gene. The clinical features expand the previously reported phenotype of B3GAT3 mutations and of linkeropathies in general. This patient has short stature, facial dysmorphisms, skeletal findings, joint laxity, and cardiac manifestations similar to those previously associated with B3GAT3 mutations. However, he also has developmental delay, a refractive errors, dental defects, pectus carinatum, and skin abnormalities that have only been associated with linkeropathies caused by mutations in B4GALT6 and B4GALT7. He has bilateral inguinal hernias and atlanto-axial as well as atlanto-occipital instability that have not been previously associated with B3GAT3 mutations. We provide a detailed clinical report and a comparative overview of the phenotypic features of the linkeropathies caused by mutations in B3GAT3, B4GALT6, and B4GALT7.

Endonasal endoscopic versus transoral microscopic odontoid resection

Abstract Objectives: Surgical approaches for odontoid resection have traditionally utilized a transoral microscopic technique, which may carry significant morbidity. Endonasal endoscopic odontoid resection represents a new technique that provides direct, minimal access to the odontoid process. We conducted a systematic review of case series and case reports to assess the role of endoscopy in the management of ventral cervicomedullary compression. Methods: MEDLINE (1950–2010) database search to identify relevant studies. Clinical outcomes were classified into “improved”, “stable”, or “deteriorated” groups. Statistical analyses of categorical variables were carried out by using χ2 and Fisher’s exact tests. Results: The endonasal cohort had a significantly lower rate of soft palate incision (0.0% vs. 33.6%; P=0.005). In the endonasal cohort, there were no cases of postoperative soft palate repair, atlanto-occipital instability, cerebrospinal fluid leak, or meningitis. Patients in the endonasal group had a shorter time to extubation (P&lt;0.0001) and oral feeding (P=0.0025). There was a significantly higher percentage of patients with improved outcome in the endonasal cohort (100% vs. 73.3%; P=0.009). Conclusions: Our systematic review supports the endonasal endoscopic approach as a safe and effective alternative to traditional transoral surgery for odontoid lesions. Careful patient selection is critical to obtaining satisfactory removal and low postoperative complications.