A Concomitant Occurrence of the Atlantoaxial Subluxation with Rare Vertebral Formation and Segmentation Defects

An atlantoaxial subluxation from the unstable Os odontoideum by the failure of proper integrations between the embryological somites might be a commonly reported pathology. However, its suspicious origin or paralleled occurrence with other congenital anomalies of vertebral body might be a relatively rare phenomenon. The authors present two cases, who simply presented with clinical signs of prolonged, intractable cervicalgia without any neurological deficits, revealed this rare feature of C1–2 subluxation from the unstable, orthotropic type of Os odontoideum that coincide with congenitally fused cervical vertebral bodies between C2–3. Surprisingly, in one case, when traced from the lower cervical down to the thoracic-lumbar levels during the preoperative work-up process, was also compromised with multi-level butterfly vertebrae formations. Presented cases highlight the association of various congenital vertebrae anomalies and the rationale to fuse only affected joints.

“CRANIO-VERTEBRAL JUNCTION ANOMALIES- SPECTRUM ON MAGNETIC RESONANCE IMAGING”

OBJECTIVE: This prospective study was done in the Department of Radiodiagnosis, King George Medical University, Lucknow, over the period of one year from September 2007 to July 2008. The purpose of this study was to evaluate the spectrum of cranio-vertebral junction anomalies on Magnetic resonance imaging (MRI). Fourty patients for whom MRI of cervical spine inc METHODS: luding cranio-vertebral junction was done for varying symptoms and showed imaging features of cranio-vertebral junction anomalies were selected for the study. Results were presented in numerical and percentage forms. There were 34 males and 6 female patients i RESULTS: n the age range of 3-60 years. Maximum number of patients were in the age group between 11-20 years (18 patients-45%) followed by age group of 21-30 years (7 patients-17.5%). Most common presenting symptom was weakness of both upper & lower limbs seen in 16 patients (40 %) followed by neck pain & stiffness in 15 patients (37.5%) and sensory symptoms in 11 patients (27.5%). Weakness of lower limbs, lower cranial nerve dysfunction & bladder bowel symptoms were the least common presenting symptoms seen only in 1 patient (2.5%). Atlanto-axial instability was the most common abnormality present in 30 patients (75%). Occipitilisation of atlas was the second most common abnormality seen in 20 patients (50%) and basilar invagination; third most common abnormality seen in 14 patients (35%). Other less commonly found abnormalities were ossiculum terminale (in 6 patients-15%), platybasia (in 5 patients-12.5%), aplasia of atlas arches(in 3 patients-7.5%), os odontoideum(in 3 patients-7.5%), segmentation failure of C2-C3 (in 3 patients7.5%), clivus segmentation (in 2 patients-5%). Atlanto-axial fusion(in 1 patient 2.5%) & hypoplasia of dens (in 1 patient 2.5%). Most common associated feature was syrinx formation found in 9 patients (22.5%). Out of 40 patients, 34 patient had developmental anomalies (85%) while 6 patients had acquired causes, including tubercular in 5 patients-12.5% & rheumatoid arthritis in 1 patient -2.5%. Myelopathic changes were found in 28 patients (70%) out of which motor symptoms were present in 25 patients (89.29%) .

Lateral Suboccipital Craniotomy With C1-C2 Hemilaminectomies and C1-C3 Fusion for the Treatment of a C1-C2 Synovial Cyst Causing Spinal Cord Compression: 2-Dimensional Operative Video

Atlantoaxial synovial cysts are a rare cause of cervical myelopathy. Here we describe a case of a 26-yr-old woman who presented with progressively decreasing right arm and leg strength and associated gait imbalance. On examination, she had diffuse weakness in the right upper and lower extremities, a positive right-sided Hoffman sign, and clonus in the right lower extremity. Computed tomography demonstrated an os odontoideum and a retro-odontoid cyst. Magnetic resonance imaging demonstrated a T1 hypointense, T2 hyperintense, slightly rim-enhancing retro-odontoid cyst causing a marked narrowing of the spinal canal, with resultant flattening and leftward deviation of the spinal cord. The patient consented to undergo cyst fenestration via a right suboccipital craniotomy and right C1-C2 hemilaminectomies, along with a C1-C3 instrumented posterior spinal fusion. This approach was chosen because it allows for cyst fenestration and instrumentation of the hypermobile cervical spine within the same incision. After the dura was opened and the arachnoid was dissected, the cyst was visualized compressing the spinal cord. The cyst was fenestrated just inferior to the C1 nerve rootlets, resulting in immediate egress of a gelatinous content; thereafter, all accessible cyst wall portions were removed. Fusion was performed with lateral mass screws at C1 and C3 and pars screws at C2. Pathological analysis described the cyst content as reactive fibrovascular tissue with cholesterol deposition. There were no complications associated with the procedure, and the patient's right-sided weakness had nearly resolved by postoperative day 1. Patient consent was granted for publication.

Posterior occipitocervical instrumented fusion for atlantoaxial instability in a 27-month-old child with Down syndrome: illustrative case

BACKGROUND Upper cervical spine instability is one of the most serious orthopedic problems in patients with Down syndrome. Despite the recent advancement of instrumentation techniques, occipitocervical fusion remains technically challenging in the very young pediatric population with small and fragile osseous elements. OBSERVATIONS A 27-month-old boy with Down syndrome was urgently transported to the authors’ hospital because of difficulty in standing and sitting, weakness in the upper limbs, and respiratory distress. Radiographs showed os odontoideum, irreducible atlantoaxial dislocation, and substantial spinal cord compression. Emergency posterior occipitoaxial fixation was performed using O-arm navigation. Improvement in the motor paralysis of the upper left limb was observed from the early postoperative period, but revision surgery was needed 14 days after surgery because of surgical site infection. The patient showed modest but substantial neurological improvement 1 year after the surgery. LESSONS There are several clinical implications of the present case. It warns that Down syndrome in the very young pediatric population may lead to rapid progression of spinal cord injury and life crisis. This 27-month-old patient represents the youngest case of atlantoaxial instability in a patient with Down syndrome. O-arm navigation is useful for inserting screws into very thin pedicles.

RARE CONGENITAL ANOMALIES AT THE CRANIOVERTEBRAL JUNCTION; OS ODENTOIDEUM

Aim: We aimed to identify dislocation, myelomalacia, and other congenital pathologies that may cause neurological complications arising from the odontoid process in the craniocervical junction (CVJ) of patients who were performed cervical tomography due to various complaints. Materials and Methods: Patients who were performed cervical CT with various complaints between 2010 and 2018 were retrospectively screened and evaluated, from the hospital registry system. Segmentation and fusion anomalies arising from the odontoid process in the craniovertebral junction area, as well as other accompanying pathologies such as subluxation, dislocation, compression to the spinal cord, and myelomalacia were also recorded. An additional 1.5 Tesla cervical MRI was performed for the 12 patients with os odontoideum. Radiological evaluation was performed on the workstation by an experienced radiologist. Results: 2525 patients with cervical CT were included in the study. 67 of these patients had congenital anomalies at the CVJ. 13 of 67 patients had os odontoideum, 38 had Klippel-Feil syndrome (KFS). Atlanto-occipital assimilation (AOA) and KFS often saw together. Only AOA was observed in 16 cases. Neck pain and limitation of movement were the most common findings in patients with congenital anomalies in the CVJ region. Conclusion: Congenital anomalies at the CVJ region, although rare, can cause mortality or morbidity. Cervical CT and MRI studies on the CVJ region should be evaluated carefully by the clinicians due to the risk of various complications.

Os Odontoideum: A Single-Center Experience with Controversies in Management and Evolution of Treatment Strategies

Os odontoideum is an independent ossicle of variable size and shape separated from the body of C2. There are various theories on the etiology. Different hypothesis on etiology include traumatic and congenital. Because of the laxity of the ligaments associated with the anomalous odontoid, there can be associated instability at the craniovertebral junction. The authors presented their experience of treating these anomalies, their clinical presentations, evolution of the treatment strategies over years, and a brief review of literature on etiopathogenesis.

Atlantoaxial Stabilization by Posterior C1 and C2 Screw-Rod Fixation for Various Pathologies: Case Series and Comprehensive Review of Literature

We retrospectively analyzed atlantoaxial dislocation (AAD) of various pathologies, namely, rheumatoid arthritis (RA), os odontoideum, and trauma. Various techniques were discussed in relation to C1-C2 stabilization. The study aims to share our clinical experience in a series of six cases of C1-C2 instability that underwent posterior C1-C2 fusion, with free hand technique and limited fluoroscopy. The clinicoradiological presentation for each patient is described. We reviewed different literatures related to our case vividly and focused on the basic neuroanatomy involved in the atlantoaxial joint. All patients of AAD had evidence of severe canal compromise and chronic compressive spinal cord changes. In our study, the patients age ranged from 28 to 52 years. The study included four males and two females. Out of six patients of AAD, three had history of trauma, two had os odontoideum, and one had chronic inflammatory condition (RA). From our case series, we concluded that the Goel–Harms technique is the most versatile and surgeon friendly technique for C1-C2 fixation. Early recognition and surgical intervention of atlantoaxial joint instability is essential to prevent catastrophic neurological complications.

Transoral approach using a tubular retractor system in the treatment of atlantoaxial Pott’s disease: a novel method of surgical decompression

The use of tubular retractors in minimally invasive spine surgery has been described extensively in the literature. However, there are only select reports discussing their use specifically in a transoral approach for upper cervical pathologies such as an epidural abscess and a dystrophic os odontoideum.We report the first use of a transtubular transoral approach in a rare case of an adult presenting with severe neck pain with progressing neurologic signs secondary to atlantoaxial Pott’s disease. Debridement and partial odontoidectomy performed using this approach allowed less trauma to surrounding soft tissues without sacrificing an excellent visualisation of the operative field. A halo vest was applied to provide temporary stability. The patient transitioned out of his halo vest after 6 months while completing medical therapy after a year without need for further intervention. The transtubular transoral approach is a suitable alternative to the conventional approach in patients with atlantoaxial Pott’s disease.