Transtubular Transoral Approach for Irreducible Ventral Craniovertebral Junction Compressive Pathologies: Surgical Technique and Outcome

@#Introduction: To investigate the use of a tubular retractor to provide access to the craniovertebral junction (CVJ) sparing the soft palate with the aim of reducing complications associated with traditional transoral approach but yet allowing adequate decompression of the CVJ. Materials and methods: Twelve consecutive patients with severe myelopathy (JOA-score less than 11) from ventral CVJ compression were operated between 2014-2020 using a tubular retractor assisted transoral decompression. Results: All patients improved neurologically statistically (p=0.02). There were no posterior pharynx wound infections or rhinolalia. There was one case with incomplete removal of the lateral wall of odontoid and one incidental durotomy. Conclusions: A Tubular retractor provides adequate access for decompression of the ventral compression of CVJ. As the tubular retractor pushed away the uvula, soft palate and pillars of the tonsils as it docked on the posterior pharyngeal wall, the traditional complications associated with traditional transoral procedures is completely avoided.

Treatment strategy and curative effect analysis of os odontoideum complicated with atlantoaxial joint dislocation / 中国骨伤

OBJECTIVE@#To explore the treatment strategy and clinical efficacy for os odontoideum complicated with atlantoaxial dislocation.@*METHODS@#The clinical data of 17 patients with os odontoideum complicated with atlantoaxial dislocation surgically treated from January 2006 to January 2015 were retrospectively analyzed, including 7 males and 10 females, aged 17 to 53 (43.1±11.3) years old;course of disease was 3 to 27(10.2±6.9) months. All patients received cranial traction before operation, 12 of 14 patients with reducible dislocation were treated by posterior atlantoaxial fixation and fusion, and 2 patients with atlantooccipital deformity were treated by posterior occipitocervical fixation and fusion;3 patients with irreducible alantoaxial dislocation were treated by transoral approach decompression combined with posterior atlantoaxial fixation and fusion. The operation time, intraoperative blood loss and perioperative complications were recorded. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the change of neck pain and neurological function. Atlantoaxial joint fusion rate was evaluated by CT scan.@*RESULTS@#The operation time of posterior fixation and fusion ranged from 86 to 170 (92.2±27.5) min, and the intraoperative blood loss was 200-350 (250.7±65.2) ml. No vertebral artery injury and spinal cord injury were recorded. Among the patients underwent atlantoaxial fixation and fusion, 1 patient with reducible dislocation fixed by C@*CONCLUSION@#Surgical treatment of os odontoideum complicated with atlantoaxial dislocation can achieve satisfactory results, improve the patient's neurological function and improve the quality of life, however the surgical options needs to be individualized.

Posterior Sublaminar Wiring and/or Transarticular Screw Fixation for Reducible Atlantoaxial Instability Secondary to Symptomatic Os Odontoideum: A Neglected Technique?

STUDY DESIGN: Retrospective case analysis. PURPOSE: We retrospectively evaluated the clinical and radiological outcomes of posterior sublaminar wiring (PSLW) and/or transarticular screw fixation (TASF) for reducible atlantoaxial instability (AAI) secondary to os odontoideum. OVERVIEW OF LITERATURE: Limited information is available about the surgical outcomes of symptomatic os odontoideum with AAI. METHODS: We examined 23 patients (12 women and 11 men) with os odontoideum and reducible AAI. The average age of the patients at the time of the operation was 44.2 years. The average follow-up duration was 4.5 years. Thirteen patients with anterior AAI underwent PSLW alone, while 10 patients with combined (anterior+posterior) AAI underwent PSLW and TASF. An autogenous iliac bone graft was used for all patients. Nine patients complained of neck or suboccipital pain, and 14 complained of myelopathy. RESULTS: Angulational instability (preoperative 18.7°±8.9° vs. postoperative 2.1°±4.6°, p<0.001), translational instability (16.3±4.9 mm vs. 1.8±2.2 mm, p<0.001), and segmental angle of the C1–C2 joint (23.7°±7.2° vs. 28.4°±3.8°, p<0.05) showed significant improvement postoperatively. Neck Visual Analog Scale score (6.2±2.4 vs. 2.5±1.8, p<0.05) and the modified Japanese Orthopedic Association (9.1±3.1 vs. 13.2±2.6, p<0.05) score also improved, with a recovery rate of 51.8%. Among the three patients who developed nonunion and/or wire breakage, one underwent revision surgery with repeat PSLW and was finally able to achieve fusion. The final fusion rate was 91.3%. CONCLUSIONS: PSLW and/or TASF provided satisfactory clinical and radiological outcomes in reducible AAI secondary to os odontoideum without significant neurological complications. Our results suggest that PSLW and/or TASF can be considered a viable surgical option over segmental fixation in highly selected cases of os odontoideum with reducible AAI.

Influence of Atlantoaxial Fusion on Sagittal Alignment of the Occipitocervical and Subaxial spines in Os Odontoideum with Atlantoaxial Instability

STUDY DESIGN: Retrospective case analysis. PURPOSE: We hypothesized that larger the C1–C2 fusion angle, greater the severity of the sagittal malalignment of C0–C1 and C2–C7. OVERVIEW OF LITERATURE: In our experience, instances of sagittal malalignment occur at C0–C1 and C2–C7 following atlantoaxial fusion in patients with Os odontoideum (OO). METHODS: We assessed 21 patients who achieved solid atlantoaxial fusion for reducible atlantoaxial instability secondary to OO. The mean patient age at the time of the operation was 42.8 years, and the mean follow-up duration was 4.9 years. Radiographic parameters were preoperatively measured and at the final follow-up. The patients were divided into two groups (A and B) depending on the C1–C2 fusion angle. In group A (n=11), the C1–C2 fusion angle was ≥22°, whereas in group B, it was <22°. The differences in the radiographic parameters of the two groups were evaluated. RESULTS: At the final follow-up, the C1–C2 angle was increased. However, this increase was not statistically significant (18° vs. 22°, p=0.924). The C0–C1 angle (10° vs. 5°, p<0.05) and C2–C7 angle (22° vs. 13°, p<0.05) significantly decreased. The final C1–C2 angle was negatively correlated with the final C0–C1 and C2–C7 angles. The final C0–C1 angle (4° vs. 6°, p<0.05) and C2–C7 angle (8° vs. 20°, p<0.05) were smaller in group A than in group B. After atlantoaxial fusion, the C0–C1 range of motion (ROM; 17° vs. 9°, p<0.05) and the C2–C7 ROM (39° vs. 31°, p<0.05) were significantly decreased. CONCLUSIONS: We found a negative association between the sagittal alignment of C0–C1 and C2–C7 after atlantoaxial fusion and the C1–C2 fusion angle along with decreased ROM. Therefore, overcorrection of C1–C2 kyphosis should be avoided to maintain good physiologic cervical sagittal alignment.

Imaging diagnosis of os odontoideum / 实用放射学杂志

Objective To investigate the imaging manifestations of os odontoideum and to improve the level of diagnosis and treatment of this disease.Methods Imaging data of 22 patients with os odontoideum were analyzed retrospectively.Results Os odontoideum was divided into round,oval,conical and irregular shapes,with intact cortex and hypertrophy of anterior arch of atlas.Two cases of orthotopic and 20 cases of dystopic os odontoideum were included.There was no displacement of the base of the odontoid process in 7 cases,with anterior displacement in 6 cases and posterior displacement in 9 cases.A widening of anterior atlanto-axial joint space with varying degrees was observed in 14 cases.Thickening of the soft tissue posterior to the odontoid process was showed in 18 cases,spinal canal stenosis in 21 cases,spinal cord degeneration in 11 cases and craniocervical junction malformation in 9 cases.Conclusion Os odontoideum is a well-corticated bone mass,with other related changes,such as hypertrophy of anterior arch of atlas,small posterior arch of atlas,atlantoaxial instablity, spinal stenosis and so on.The imaging features can provide important reference for clinical diagnosis and treatment.

Comparison of Cervical Alignment and Clinical Outcomes in Patients with Os Odontoideum versus Non-Os Odontoideum after Atlantoaxial Fixation

OBJECTIVE: The purpose of this study was to compare the effect of atlantoaxial fixation on cervical alignment and clinical outcomes in patients with os odontoideum (OO) versus non-os odontoideum (non-OO). METHODS: A total of 119 patients who underwent atlantoaxial fixation for instability were identified between January 1998 and January 2014. Inclusion criteria included age more than 21 years and diagnosis of OO and non-OO. There were 22 OO patients, and 20 non-OO patients. Measuring the Oc–C1 Cobb angle, C1–2 Cobb angle, C2–7 Cobb angle, and C2–7 sagittal vertical axis (SVA) was assessed. Clinical outcome was assessment of suboccipital pain was determined using a visual analogue scale (VAS), and Japanese Orthopedic Association (JOA) scores were obtained in all patients pre- and postoperatively. RESULTS: The preoperative C1–2 angle in the OO group (26.02°±10.53°) was significantly higher than the non-OO group (p=0.04). After C1–2 fixation, the OO group had significantly higher kyphotic change in the C1–2 angle (ΔC1–2) (3.2°±7.3° [OO] vs. −1.46°±7.21° [non-OO]) (p=0.04), and higher decrease in postoperative C2–7 SVA (ΔC2–7 SVA) (5.64±11.56 mm [OO] vs. −0.51± 6.57 mm [non-OO]) (p=0.04). Both groups showed improvements in the health related quality of life (HRQOL) after surgery based on the VAS and JOA score (p < 0.001). CONCLUSION: After fixation, kyphotic angular change in atlantoaxial joint and decrease C2–7 SVA were marked in the OO group. Both the OO and non-OO groups improved in neurological function and outcome after surgery.

Challenges of Transarticular Screw Fixation in Young Children: Report of Surgical Treatment of a 5-Year-Old Patient's Unstable Os-Odontoideum

Surgical procedures for atlantoaxial (C1–C2) fusion in young children are relatively uncommon. The purpose of this study was to report on a surgical treatment for a case of atlantoaxial instability caused by os-odontoideum in association with quadriparesis and respiratory paralysis in a 5-year-old girl. We present the patient's history, physical examination, and radiographic findings, describe the surgical treatment and a five year follow-up, and provide a literature review. The instability was treated by halo immobilization, followed by C1–C2 transarticular screw fixation using a computed tomography-based navigation system. At the five year follow-up, the patient had made a complete recovery with solid union. The authors conclude that C1–2 transarticular screw fixation is technically possible as in a case of atlantoaxial instability in a five-year-old child.

Transtubular Transoral Surgery for Excision of a Dystrophic Os Odontoideum: A Case Report

Transoral approach to the cervico-medullary junction is a well-established procedure. However oropharyngeal complications in the form of soft tissue morbidity postoperatively do occur. We report a case of a teenage boy with traumatic quadriparesis secondary to compression of the cervico-medullary junction by an os odontoideum. Decompression was done via transoral approach through a tubular retractor system, hence obviating the need for the splitting or separate retraction of the soft palate and minimised the damage and violation of surrounding soft tissues. His neurological status improved and he was able to ambulate with support on fourth post-operative day with no soft tissue morbidity in the oral cavity. To our knowledge this is the first case reported using this technique. We conclude that adoption of this method would improve the traditional transoral approach and reduce the oropharyngeal complications.

Occipito-thoracic Fusion in Incidental Dystropic Os Odontoideum in a patient suspected with Osteogenesis Imperfecta: A Case Report.

Introduction: Os odontoideum is a rare lesion of the axis. Described as an ossicle, consisting of smooth and separate caudal portions of the odontoid process wherein its etiology has remained controversial. Os odontoideum complicating a possible osteogenesis imperfecta has not been reported before in the literature. Methods: We report the case of a 14-yr male patient presented with progressive weakness of both lower and upper extremities after a head trauma 10 months prior to admission, which presented as transient quadreparesis. Results: Magnetic resonance imaging of cervical spine showing cervicomedullary junction compression. Patient underwent surgical intervention and 3 months post operation, patient was reported to have steady gait and muscle grading of 5/5 on all extremities. Conclusion: Surgical fi xation and fusion in patients with instability may prevent catastrophic neurologic insult after minor trauma in the future.

Retro-odontoid Synovial Cyst with Os Odontoideum and Atlantoaxial Instability

We report the case of a patient with a retro-odontoid synovial cyst, coupled with os odontoideum and atlantoaxial instability. We observed the regression of the cyst after C1-2 transarticular screw fixation and posterior wiring without direct surgical excision of the cyst on the follow-up MR images, which were obtained two and three months postoperatively. The myelopathic symptoms and signs of this patient were resolved by degrees.

The Results and Complications of the C1-C2 Transarticular Screw Fixation Methods

OBJECTIVE: To evaluate the accuracy and safety of C1-C2 transarticular screw insertion, we retrospectively review surgical records and postoperative radiological findings. METHODS: From January 2001 to October 2003, the C1-C2 transarticular screw fixation and posterior wiring with iliac bone grafts was performed in 16 pateints. 6 patients had rheumatoid arthritis which caused cervical instability, 3 patients had os odontoideum, 3 patients had type 2 odontoid process fracture, 3 patients had traumatic transverse ligament injury and 1 patients who had been managed with C1-C2 wire fixation had psoriatic arthritis. RESULTS: Osseous fusion was documented in 15 patients(93.8%). Only one patient was recorded screw loosening because of postoperative infection. One patient had only one screw placed because of abnormal anatomical structure, one patients was breakage of a Kirschner wire, and one screw was medial location to lateral mass of C1, but clinical results was excellent and radiological instability was not noted. CONCLUSION: The author's experience demonstrates that C1-C2 transarticular screw fixation with wired bone graft is a safe procedure with higher fusion rate but precaution is needed to avoid the neural damage, vertebral artery injury, and hardware failure.

Quadriplegia and Dyspnea Caused by Os Odontoideum in a Down Syndrome Patient: A case report

Os odontoideum is a rare anomaly of the second cervical vertebrae, which is a separated ossicle from the body of the axis. This abnormality of the odontoid process can result in an atlanto-axial instability & subsequent cervical cord compression. In spite of the high prevalence of atlanto-axial instability due to the ligamentous laxity of atlanto-axial joint, the frequency of neurologic symptoms is relatively low in the patient of the Down syndrome. The asymptomatic atlanto-axial instability by trauma may progress to Os odontoideum in Down syndrome population and may cause cervical cord compression. Therefore, early recognition and an appropriate management of patients with atlanto-axial instability can significantly reduce the morbidity and mortality. We report a case of Os odontoideum in a child with Down syndrome, who had an atlanto-axial instability which resulted in the cervical cord compression.

Long Term Follow up and Clinical Results of Posterior C1/2 Fixation

OBJECTIVE: To determine the efficacy of various posterior fusion techniques in managing C1/2 instability. PATIENTS AND METHODS: Retrospective review of patients undergoing C1/2 posterior fusioin was undertaken with the aim of determining the long-term outcome of the selected procedures. Forty-two patients requiring posterior atlantoaxial fusion for various pathologies were treated with various instruments for internal spinal fixation. Forty-two patients underwent 45 procedures from 1990 to 1997, with a mean follow-up of 2.7 years(range 8 months-7 years) RESULTS: The most common disease processes were odontoid fracture(12 patients), os odontoideum(13), and rheumatoid instability(7). Nineteen interspinous wirings, 17 transarticular screw fixations, 9 halifax clamp applications were performed. Three of Halifax fixation and 2 of wiring failed in long term follow up. Among of them, bony fusion was failed in 3 patients which consequently required reoperation. All transarticular screw procedures resulted in successful fusions. CONCLUSIONS: Transarticular screw fixatioin has several potential advantages compare to other procedures as a technique for C1/2 posterior arthrodesis.

Synovial Cyst of Transverse Ligament of Axis in a Patient with Os Odontoideum and Atlantoaxial Instability: A Case Report / 대한척추외과학회지

STUDY DESIGN: A case report and review of the literature. OBJECTIVES: To describe the diagnosis and successful treatment of the synovial cyst arising from the transverse ligament in a patient with Os odontoideum and atlantoaxial instability. SUMMARY OF LITERATURE REVIEW: Synovial cyst arising from the transverse ligament of the axis is extremely rare and thought to be attributed to degenerative changes of the C1-C2 facet joints or microtraumas. Direct excision of the cyst is the only treatment method described in previous reports. MATERIALS AND METHODS: A case of synovial cyst arising from the transverse ligament of the axis in a 45-year-old man with Os odontoideum and atlantoaxial instability was managed with posterior atlantoaxial fusion alone. The characteristic MRI findings and surgical treatment, and related literature are reviewed. RESULTS: MRI of the cervical spine showed a large cystic mass located at the transverse ligament of the axis which was com-pressing the spinal cord near the C1-C2 junction: the images showed a low signal intensity on T1WI; high signal intensity on T2WI; and rim enhancement with no internal enhancement on Gadolinium enhanced T1WI. The spontaneous resolution of the cyst was identified on the follow-up MRI taken at 3 months after operation and clinical improvement was achieved. CONCLUSIONS: The MRI findings of spontaneous resolution of synovial cyst arising from the transverse ligament of the axis after posterior atlantoaxial fusion alone suggest that stable fusion rather than direct excision of the cyst should be considered over the surgical option when the location of the cyst is difficult or dangerous to approach surgically.

C1/2 Transarticular Screw Fixation for Complicated Os Odontoideum: Case Report

C1/2 posterior transarticular screw fixation has become an accepted method of rigid internal fixation for patients requiring posterior C1/2 fusion. Especially,Surgery for Os odontoideum can be troublesome due to its severe tranlational instability, canal stenosis requiring decompressive laminectomy and defective C1 posterior arch. The author reports three cases of complicated Os odontoideum(one case of failed occipito-C2 fusion, two cases requiring C1 laminectomy) with C1/2 transarticular screw fixation and interarticular bone fusion. All required decompressive laminectomy and demonstrated highly unstable translational instabilities. On the basis of these experiences, it is postulated that C1/2 transarticular screw fixation seems to be superior to other methods in stabilization and fusion for complicated Os-odontoideum.

Diagnosis and Management of Os Odontoideum

The authors analyzed 17 cases of os odontoideum. a very rare condition and one of the causes of atlantoaxial instability. We investigated the radiographic findings of os odontoideum and classified the patients according to clinical grade, radiographic findings and direction of atlantoaxial instability. Their mean age was 33.4 years, and the male to female ratio was. 7: 10. Thirteen patients(76.5%) were classified as clinical grade 3, indicating fixed or progressive myelopathy. They were classified as one of two types, according to the location of the os, five were dystopic and ten were orthotopic. In remaining two patients, it was difficult to classify. We measured SAC(space available for cord) laterally, using plain film, and sagittally, using MR imaging, and compared the results with clinical symptoms. SAC as seen on cervical MRI, correlated more closely with severity of cord compression than did SAC seen on plain film. The 15 patients underwent various operative methods including C1/2 fixation, occipito-cervical fusion, and transoral decompression; because of postoperative hardware failure, two required further surgery. Postoperatively, twelve patients showed excellent or good neurologic improvement. In this retrospective study, SAC seen on cervical MRI was a very good indicator of the need for surgery, and surgery should be considered in patients whose clinical grade is higher than 2.

Transoral Decompression and Anterior Fusion of Atlanto-axial Dislocation due to Os Odontoideum: Case Report

The Os odontoideum is a developmental anomaly of the axis in which the odontoid process is divided transversely. The Atlanto-axial dislocation due to Os odontoideum is presented. At first, we have performed the posterior atlanto-axial fusion with wire fixation. But the posterior fusion failed in realignment and did not adequately decompress the deformed cord by encroachment on its ventral surface. Next time, we have experienced further improvement following transoral decompression and anterior fusion.

A Case of Atlanto-axial Dislocation due to Os Odontoideum

A patient who had an atlanto-axial dislocation due to an os odontoideum is presented. She was operated on successfully with preliminary realignment of the dislocation by skeletal traction and subsequent posterior cervical fusion with wiring and iliac bone.