Odontoid calcification and crowned dens syndrome: data from a Chinese center.

OBJECTIVES: To assess the prevalence of calcification surrounding the odontoid process (odontoid calcification) with crowned dens syndrome (CDS) and without CDS (non-CDS) and investigate factors that may related to the onset of CDS. METHODS: Retrospective review of consecutive patients visited Sir Run Run Shaw Hospital between 1 January 2018 and 5 November 2019 who were identified to have odontoid calcification on cervical computed tomography (CT) images. Those who presented with an acute or subacute episode of cervico-occipital pain were defined as CDS, others were non-CDS. RESULTS: We diagnosed 69 cases of odontoid calcification among 2902 cervical CTs of 2556 patients (69/2556, 2.70%), 19 (19/2556, 0.74%) cases of which were CDS, 50 (50/2556, 1.96%) cases were non-CDS. Mean age was 71 (54-86) years old in odontoid calcification patients. The male-to-female ratio of patients with odontoid calcification was 27:42 (0.64). The prevalence of odontoid calcification was 69/1497 (6.14%) in individuals over 50 years old, The prevalence was 0.59% (4/679), 5.05% (26/515), 11.49% (27/235) and 20% (12/60) in patients aged 50-59, 60-69, 70-79 and 80-89 years old, respectively. Age and female gender were predictive factors of odontoid calcification. Lower hemoglobin (Hgb), red blood cell count (RBC), higher C-reactive protein (CRP), pain scale score were found in CDS patients comparing with non-CDS group. No difference of age, gender, hypertension, diabetes mellitus, smoking, alcohol history, creatinine, white blood cell count, mean corpuscular volume, uric acid, calcium was found between the two groups. CONCLUSIONS: Odontoid calcification is a common radiological entity in patients older than 50 years. Lower Hgb, RBC, higher CRP, pain scale score were found in CDS patients comparing with non-CDS.

Basilar invagination associated with chiari malformation type I: A literature review.

Basilar invagination (BI) and Chiari malformation type I (CM-I) are very important anomalies that introduce instability and compression in the occipitocervical transition region and have complex clinical characteristics. These anomalies vary according to the affected structures. The present study revises current knowledge regarding the anatomy, anatomo-physiology, clinical manifestations, and radiological findings of these entities and the associated surgical treatment approaches. A bibliographic survey was performed through a search in the Medline, PubMed, SciELO, Science and LILACS databases. When associated, these craniovertebral malformations result in neurological deficits due to neural parenchyma compression; however, the presence of microtraumas due to repetitive lesions caused by the bulb and cervical marrow instability has been highlighted as a determinant dysfunction. Surgical treatment is controversial and has many technical variations. Surgery is also challenging due to the complex anatomical characteristics and biomechanics of this region. Nevertheless, advances have been achieved in our understanding of related mechanisms, and compression and atlantoaxial instability are considered key elements when selecting the surgical approach.

Traumatic Atlantoaxial and Fracture-Related Dislocation.

Traumatic atlantoaxial dislocation due to ligamentous and combined osseous injuries rarely occurs in adults. There are only few cases published in the literature. In this level 4 study, a cohort of nine consecutive patients suffering from traumatic atlantoaxial dislocation has been analyzed regarding morphology of injury, trauma mechanism, and outcome since 2007. Three types of those injuries have been found regarding direction of dislocation indicating the underlying ligamentous injuries as well as the accompanying grade of instability. Firstly, there was rotatory dislocation, if the alar ligaments were injured. Secondly, there occurred horizontal dislocation, when transverse atlantal ligament was damaged additionally. Thirdly, excessive ligamentous injury led to distraction of the atlantoaxial complex resulting in dissociation of the atlas against the axis. Additionally fractures of the atlas as well as of the odontoid process (type II or III according to Anderson/D'Alonzo) were diagnosed frequently. Atlantoaxial dislocation injuries, especially distraction injuries, offer a high risk for accompanied neurovascular disorders deserving reduction followed by surgical fixation. Only rotatory injuries leading to ligamentous damage solitarily can safely be successfully treated conservatively. Understanding of the injuries' morphology is essential, in order to set the correct diagnosis and to implicate the most advantageous treatment regime.

Management of Type II Odontoid Fractures in Adults.

Fractures of the odontoid represent as much as 20% of cervical spine fractures in adults, and they are the most common spine fracture in patients over 80 years of age. Despite their prevalence, the management of these fractures remains highly controversial. In particular, there is much debate concerning the management of type II fractures, or fractures occurring about the waist of the odontoid. We will review the epidemiology, evaluation, management-both operative and non-operative-and outcomes of adults with type II odontoid fractures. We will particularly focus on debates concerning hard collar versus halo, anterior versus posterior surgery, the management of odontoid nonunions, as well as questions about risks and benefits of surgery in the very elderly.

Atlantoaxial Instability Resulting in Intractable Nausea in a Person with C5 Complete Spinal Cord Injury: A Case Report.

Individuals with spinal cord injury (SCI) have altered neurophysiology and present with symptoms that must be interpreted in the context of their specific neurologic injury. This is a case of a 16-year-old female adolescent with C5 American Spinal Injury Association Impairment Scale A SCI who presented with intractable nausea. Multiple etiologies for her nausea, including medication effect, metabolic and gastrointestinal disorders, autonomic dysreflexia, and mood disorder, were systematically ruled out. Due to the persistence of the patient's symptoms and suboptimal progression in her rehabilitation, a central nervous system etiology was investigated. Ultimately, atlantoaxial instability with odontoid compression on the medulla was identified and her refractory nausea resolved following an occiput to C2 fusion. To our knowledge, this is the first reported case of atlantoaxial instability causing intractable nausea due to brain stem compression in a patient with SCI. Level of Evidence: V.

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.

Biomechanical contributions of upper cervical ligamentous structures in Type II odontoid fractures.

Fractures of the odontoid present frequently in spinal trauma, and Type II odontoid fractures, occurring at the junction of the odontoid process and C2 vertebrae, represent the bulk of all traumatic odontoid fractures. It is currently unclear what soft-tissue stabilizers contribute to upper cervical motion in the setting of a Type II odontoid fracture, and evaluation of how concomitant injury contributes to cervical stability may inform surgical decision-making as well as allow for the creation of future, accurate, biomechanical models of the upper cervical spine. The objective of the current study was to determine the contribution of soft-tissue stabilizers in the upper cervical spine following a Type II odontoid fracture. Eight cadaveric C0-C2 specimens were evaluated using a robotic testing system with motion tracking. The unilateral facet capsule (UFC) and anterior longitudinal ligament (ALL) were serially resected to determine their biomechanical role following odontoid fracture. Range of motion (ROM) and moment at the end of intact specimen replay were the primary outcomes. We determined that fracture of the odontoid significantly increases motion and decreases resistance to intact motion for flexion-extension (FE), axial rotation (AR), and lateral bending (LB). Injury to the UFC increased AR by 3.2° and FE by 3.2°. ALL resection did not significantly increase ROM or decrease end-point moment. The UFC was determined to contribute to 19% of intact flexion resistance and 24% of intact AR resistance. Overall, we determined that Type II fracture of the odontoid is a significant biomechanical destabilizer and that concurrent injury to the UFC further increases upper cervical ROM and decreases resistance to motion in a cadaveric model of traumatic Type II odontoid fractures.

Basilar invagination associated with chiari malformation type I: A literature review

Basilar invagination (BI) and Chiari malformation type I (CM-I) are very important anomalies that introduce instability and compression in the occipitocervical transition region and have complex clinical characteristics. These anomalies vary according to the affected structures. The present study revises current knowledge regarding the anatomy, anatomo-physiology, clinical manifestations, and radiological findings of these entities and the associated surgical treatment approaches. A bibliographic survey was performed through a search in the Medline, PubMed, SciELO, Science and LILACS databases. When associated, these craniovertebral malformations result in neurological deficits due to neural parenchyma compression; however, the presence of microtraumas due to repetitive lesions caused by the bulb and cervical marrow instability has been highlighted as a determinant dysfunction. Surgical treatment is controversial and has many technical variations. Surgery is also challenging due to the complex anatomical characteristics and biomechanics of this region. Nevertheless, advances have been achieved in our understanding of related mechanisms, and compression and atlantoaxial instability are considered key elements when selecting the surgical approach.

Surgical vs. non-surgical management of displaced type-2 odontoid fractures in patients aged 75 years and older: study protocol for a randomised controlled trial.

BACKGROUND: Displaced odontoid fractures in the elderly are treated non-surgically with a cervical collar or surgically with C1-C2 fusion. Due to the paucity of evidence, the treatment decision is often left to the discretion of the expert surgeon. METHODS: The Uppsala Study on Odontoid Fracture Treatment (USOFT) is a multicentre, open-label, randomised controlled superiority trial evaluating the clinical superiority of the surgical treatment of type-2 odontoid fractures, with a 1-year Neck Disability Index (NDI) as the primary endpoint. Fifty consecutive patients aged ≥ 75 years, with displaced type-2 odontoid fracture, are randomised to non-surgical or surgical treatment. Excluded are patients with an American Society of Anaesthesiologists (ASA) score ≥ 4, dementia nursing care or anatomical cervical anomalies. The minimal clinically important difference of the NDI is 3.5 points. A minimum of 16 patients are needed in each group to test the superiority with 80% power. By considering a 1-year mortality forecast of 29%, up to 25 participants are recruited in each group. The non-surgical group is fitted with a rigid cervical collar for 12 weeks. The surgical group is treated with a posterior C1-C2 fusion. All participants are monitored with regard to the NDI, EuroQol score (EQ-5D), socio-demographics and computed tomography (CT) at the time of injury, at 6 weeks, 3 months and 12 months. At 12 months, a dynamic radiographical investigation of upper cervical stability is performed. The secondary endpoints are: EQ-5D score, activities of daily living (ADL), bony union, upper cervical stability and mortality. DISCUSSION: USOFT is the first randomised controlled trial comparing non-surgical and surgical management of type-2 odontoid fractures in the elderly. Using the NDI and EQ-5D as endpoints, future value-based decisions may consider quality-adjusted life years gained. Major limitations are (1) the allocation bias of the open-label study design, (2) that only higher training levels of all core specialties of spine surgery are included in the surgical treatment arm and (3) that only one type of surgical stabilisation is investigated (posterior C1-C2 fusion), while other methods are not included in this study. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02789774 . Registered retrospectively on 25 August 2015.

Novel posterior artificial atlanto-odontoid joint for atlantoaxial instability: a biomechanical study.

OBJECTIVE Atlantoaxial instability is usually corrected by anterior and/or posterior C1-2 fusion. However, fusion can lead to considerable loss of movement at the C1-2 level, which can adversely impact a patient's quality of life. In this study, the authors investigated the stability and function of a novel posterior artificial atlanto-odontoid joint (NPAAJ) by using cadaveric cervical spines. METHODS The Oc-C7 regions from 10 cadaveric spines were used for anteroposterior (AP) translation and range of motion (ROM) tests while intact and after destabilization, NPAAJ implantation, and double-rod fixation. RESULTS The mean AP C1-2 translational distances in the intact, destabilization, and double-rod groups were 6.53 ± 1.07 mm, 11.54 ± 1.59 mm, and 3.24 ± 0.99 mm, respectively, and the AP translational distance in the NPAAJ group was significantly different from that in the intact group (p < 0.05). The AP translational distance in the NPAAJ group was not significantly different from that in the double-rod group (p = 0.24). The mean flexion, extension, and axial rotation ROM values of the NPAAJ group were 9.87° ± 0.91°, 8.75° ± 0.99°, and 61.93° ± 2.93°, respectively, and these were lower than the corresponding values in the intact group (p < 0.05). The mean lateral bending ROM in the NPAAJ group (9.26° ± 0.86°) was not significantly different from that in the intact group (p = 0.23), and the flexion, extension, and rotation ranges in the NPAAJ group were 79.5%, 85.2%, and 82.3%, respectively, of those in the intact group. CONCLUSIONS Use of NPAAJ for correction of atlantoaxial instability disorders caused by congenital odontoid dysplasia, odontoid fracture nonunion, and C-1 transverse ligament disruption (IA, IB, and IIB) may restore the stability and preserve most of the ROM of C1-2. Additionally, the NPAAJ may prevent soft tissue from embedding within the joint. However, additional studies should be performed before the NPAAJ is used clinically.

A case with rheumatod arthritis and atraumatic odontoid fracture: disappearence of bony landmarks.

We aim to draw attention to occult, atraumatic fractures of the odontoid process in patients with rheumatoid arthritis (RA) and to underline difficulties encountered during clinical and radiological diagnosis. A forty-seven years old man with RA for 4 years had occipital pain for 1 year without any history of trauma. Later, he developed weakness in the upper extremities, but he did not realize weakness in the lower extremities due to deformities. Contrast magnetic resonance imaging revealed a linear fracture of odontiod process and myelopathy. Cervical computed tomography scan revealed an old fracture border with separated and almost disappeared remnant of the tip of the odontoid without free particles in the cord. It was impossible to evaluate atlantoaxial and vertical subluxations with craniometric measurements due to destruction of the tip of odontoid. Following occipitocervical fusion and decompression and a rehabilitation program, his muscle strength improved; however, functional myelopathy stage did not change. Atraumatic fractures of the odontoid process may be more common than reported and may cause compression of the spinal cord or brain stem. Surgery is the treatment of choice but functional recovery is limited once neuronal damage has occurred. Erosion of the critical landmarks makes it difficult to diagnose and follow up atlantoaxial subluxation and/or vertical subluxation, therefore clinicians should consider radiographical follow-ups during the course of the disease.

[Influence of Osseous and Ligamentous Injuries on the Stability of the Atlantoaxial Complex]. / Einfluss osteoligamentärer Verletzungen auf die Stabilität des atlantoaxialen Komplexes.

Background The odontoid process and the transverse ligament are the most important structures stabilising the atlantoaxial complex. It has not been fully elucidated how injuries of these structures contribute towards instability and a potential narrowing of the spinal canal. Therefore, our investigation aimed to perform a biomechanical analysis of spinal width and dislocation of the odontoid process depending on injuries of the aforementioned structures. Methods In 10 fresh human cadaveric specimens, physiologic flexion and extension were simulated under fluoroscopy in intact specimens and after application of an odontoid process fracture and transverse ligament rupture in a crossover design. The width of the spinal canal and the dislocation of fragments were measured. Results In the intact condition, values of 19.8/19.5/19.8 mm (neutral/flexion/extension) were observed regarding spinal width. After an isolated fracture, values were 18.5/18.9/17.9 mm. With additional ligamentous injury, values changed to 20.3/19.4/22.6 mm. In the second group, values after initial ligament injury were 18.6/16.2/17.3 mm and 16.6/14.1/18.7 mm after fracture. Dislocation of fragments after an isolated fracture averaged 2.2/2.5/2.5 mm; an additional ligamentous injury led to 2.6/2.2/2.2 mm. In the second group, where a ligamentous injury preceded the fracture, a dislocation of 1.5/1.9/3.5 mm was detected after the fracture. Conclusion Neurological disorders have been observed starting at a spinal canal constriction of 2.0 mm. Our results demonstrate that a relevant constriction of the spinal canal may be due to isolated or combined injuries of the bone and the transverse ligament. Furthermore, our results show the importance of posttraumatic immobilisation of the spine with a view to the role of the transverse ligament for stabilisation of the atlantoaxial complex.

Odontoid Osteomyelitis in Children: Illustrative Case Reports and Review of the Literature.

Odontoid osteomyelitis is a rare disease which is frequently misdiagnosed as torticollis, leading to a delay in diagnosis. We present 2 illustrative cases and a systematic literature review summarizing previously reported cases. Odontoid osteomyelitis should be considered in children presenting with decreased head movements and with elevated erythrocyte sedimentation rate, particularly without improvement while receiving antiinflammatory treatment. Plain radiographs can be misleading, and magnetic resonance imaging should be performed for better visualization.

A Novel Anterior Odontoid Screw Plate for C1-C3 Internal Fixation: An In Vitro Biomechanical Study.

STUDY DESIGN: A biomechanical in vitro study was performed using a standardized experimental protocol in a biomechanical spine testing apparatus. OBJECTIVE: The aims of this study were to evaluate the biomechanical stability afforded by 4 cervical fixation techniques: anterior cervical plate+odontoid screw+cage (ACP+OS+cage), anterior odontoid screw plate+bone graft (AOSP+bone graft), posterior C2-3 fixation+odontoid screw (C2PS+C3LMS+OS), and posterior C1-3 fixation (C1PS+C2PS+C3LMS). SUMMARY OF BACKGROUND DATA: Unstable axis injuries with multiple fracture lines are uncommon injuries, and their management is still challenging for surgeons who aim to achieve primary stability, early mobilization, preserved cervical range of motion (ROM), and favorable outcome. We designed a novel AOSP to assist in this challenging clinical scenario. METHODS: Eight fresh-frozen cadaveric spine specimens (C1-C3) were subjected to stepwise destabilization of the C1-3 complex, with serial replication of a type II Hangman fracture, a type II odontoid fracture, and a C2 to C3 disc injury. Intact specimens, destabilized specimens, and destabilized specimens with various stabilization techniques including anterior and posterior techniques, some using our AOSP, were each tested for stability. Each spine was subjected to flexion, and extension testing, left and right lateral bending, and left and right rotation. RESULTS: After AOSP+bone graft fixation, the ROMC2-C3 during all loading modes were reduced to values that were significantly less than normal. During all loading modes, AOSP+bone graft fixation significantly outperformed the ACP+OS+cage fixation in limiting ROMC2-C3. During flexion and extension, AOSP+bone graft fixation significantly outperformed the C1PS+C2PS+C3LMS fixation and C2PS+C3LMS+OS fixation in limiting ROMC2-C3. CONCLUSION: The AOSP has excellent biomechanical performance when dealing with type I Hangman fractures, type II odontoid fractures, and C2-3 disc injuries. The AOSP+one graft fixation can preserve the function of atlanto-axial joint, which may be a valuable stabilization strategy for these unique injuries.

Complete Remodeling After Conservative Treatment of a Severely Angulated Odontoid Fracture in a Patient With Osteogenesis Imperfecta: A Case Report.

STUDY DESIGN: Case report. OBJECTIVE: This is the first case report describing successful healing and remodeling of a traumatic odontoid fracture that was dislocated and severely angulated in a patient with osteogenesis imperfecta who was treated conservatively. SUMMARY OF BACKGROUND DATA: Osteogenesis imperfecta (OI) is a rare genetic disorder resulting in a low bone mass and bone fragility, predisposing these patients to fractures that often occur at a young age. Although any bone in the body may be involved, odontoid fractures are uncommon in this population. Because of a very high fusion rate, conservative management is accepted as a safe and efficient treatment of fractures of the odontoid in children. Several authors, however, recommend surgical treatment of patients who have failure of conservative treatment and have severe angulation or displacement of the odontoid. METHODS: A 5-year-old female, diagnosed with OI type I, presented with neck pain without any neurological deficits after falling out of a rocking chair backward, with her head landing first on the ground. Computed tomography confirmed a type III odontoid fracture without dislocation and she was initially treated with a rigid cervical orthosis. At 1 and 2 months of follow-up, progressive severe angulation of the odontoid was observed but conservative treatment was maintained as the space available for the spinal cord was sufficient and also considering the patient's history of OI. RESULTS: Eight months postinjury, she had no clinical symptoms and there was osseous healing of the fracture with remodeling of the odontoid to normal morphology. CONCLUSION: Even in patients with OI, severely angulated odontoid fractures might have the capacity for osseous healing and complete remodeling under conservative treatment. LEVEL OF EVIDENCE: 5.

Immediate Reduction of a Retro-odontoid Synovial Cyst Following Lateral Atlantoaxial Joint Puncture and Arthrography: A Case Report.

STUDY DESIGN: Case report. OBJECTIVE: We report on a case with a retro-odontoid synovial cyst, and the immediate reduction of the cyst was confirmed after lateral atlantoaxial joint puncture and arthrography. SUMMARY OF BACKGROUND DATA: Retro-odontoid synovial cysts are rare diseases located posteriorly to a dense axis. Because most reports have focused on surgical treatment, only a few have examined nonsurgical treatment. However, several months are required after nonsurgical treatment until cyst regression. METHODS: A 52-year-old female presented with atlantoaxial instability. She complained of neck pain and numbness in her hands. Magnetic resonance imaging revealed a retro-odontoid synovial cyst. Lateral atlantoaxial joint puncture and arthrography were performed. RESULTS: Two days after treatment, the patient showed significant improvement in the numbness of her hands, and a follow-up magnetic resonance imaging revealed an immediate reduction in the cyst. During a 4.5-year follow-up period, no recurrence of the clinical symptoms occurred. CONCLUSION: Lateral atlantoaxial joint puncture may immediately reduce retro-odontoid synovial cysts, and the lateral atlantoaxial joint has a communication channel with the retro-odontoid synovial cyst via the atlantodental joint. Once disappearance of the cyst is confirmed, an acceptable long-term outcome can be achieved with nonsurgical treatment even in cases with atlantoaxial instability. LEVEL OF EVIDENCE: N/A.

Odontoid process and clival regeneration with Chiari malformation worsening after transoral decompression: an unexpected and previously unreported cause of "accordion phenomenon".

PURPOSE: Transoral odontoidectomy followed by occipito-cervical fixation is a widely used approach to relieve ventral compressions at the craniovertebral junction (CVJ). Despite the large amount of literature on this approach and its complications, no previous reports of odontoid process and clival regeneration following transoral odontoidectomy are present in the English literature. METHODS: We report the case of odontoid process and clival regeneration following transoral odontoidectomy. RESULTS: A 7-year-old boy presented with symptoms of brainstem and upper cervical spinal cord compression due to a complex malformation at the CVJ including a basilar invagination with Chiari malformation. A successful transoral microsurgical endoscopic-assisted odontoidectomy extended to the clivus was performed along with occipito cervical instrumentation and fusion. Clinical and radiological resolution of the CVJ compression was evident up to 2 years post-op, when the child had a relapse of some of the presenting symptoms and the follow-up CT and MRI scans showed a quite complete regrowth of the odontoid process, clival partial regeneration and recurrence of preoperative Chiari malformation. CONCLUSIONS: Besides the need of an accurate complete resection of the periosteum, which apparently was incompletely performed in our case, our experience suggests the need of resection of the odontoid down to the dentocentral synchondrosis and an accurate lateral removal of the bone surrounding the anterior tubercle of the Clivus is advised when an anterior CVJ decompression is required in children presenting a still evident synchondrosis at neuroradiological investigation.

Hematopoietic stem cell transplantation effects on spinal cord compression in Hurler.

Hurler syndrome type 1 (MPS-1) is an autosomal recessive lysosomal disorder due to the deficiency of the enzyme alpha-L-iduronidase which is necessary for the degradation of dermatan and heparan sulfate. It is characterized by deposit of glycosaminoglycans in tissues, progressive multisystem dysfunction, and early death. HSCT for children with MPS-I is effective, resulting in increased life expectancy and improvement of clinical parameters. The spinal MRI performed on a female 10 yr old undergoing HSCT at the age of 18 months and receiving ERT revealed a considerable decrease in soft tissue around the tip of odontoid causing a significant reduction in spinal cord compression. In light of this result, we suppose that combined ERT and HSCT are successful in Hurler I disease.

Rationale and design of the INNOVATE Trial: an international cooperative study on surgical versus conservative treatment for odontoid fractures in the elderly.

BACKGROUND: Fractures of the odontoid process of the axis are the most common fractures of the geriatric cervical spine. As the population ages, their incidence is expected to increase progressively, as is the number of very old patients (>80 years) with an odontoid fracture. No consensus exists on the optimal treatment (surgical or conservative) and the most relevant outcome parameter (osseous union, fracture stability or clinical outcome). The aim of the INNOVATE (INterNational study on Odontoid frActure Treatment in the Elderly) Trial is to prospectively assess fracture healing and clinical outcome after surgical and conservative treatment for odontoid fractures in the elderly patient, with a specific focus on the very old patient. METHODS/DESIGN: The trial is an observational study in which eleven centres in five European countries are involved. All patients admitted to one of these centres who meet the selection criteria (≥55 years, acute (