-
American Journal of Veterinary Research Nov 2023To investigate the feasibility of using shape memory alloy (SMA) implants for atlantoaxial joint stabilization using a rabbit model as a substitute for canines.
OBJECTIVE
To investigate the feasibility of using shape memory alloy (SMA) implants for atlantoaxial joint stabilization using a rabbit model as a substitute for canines.
ANIMALS
20 rabbit cadavers.
METHODS
We prepared rabbit cadavers from the middle of the skull to the third cervical vertebra. The vertebral body and canal sizes of the atlas and axis were compared using CT data from rabbits, normal dogs, and dogs with atlantoaxial instability (AAI) to assess the feasibility of using rabbits as substitutes for toy-breed dogs. The shape memory alloy (SMA) implants were designed to stabilize the atlantoaxial joint without compromising the spinal canal passage for safety and were classified into SMA-1 and SMA-2 based on their design. To evaluate the strength, the ventrodorsal force was measured with atlantoaxial ligaments intact, after removing the ligaments, and after applying conventional wire or SMA implants to stabilize the atlantoaxial joint. The time taken for implant application was measured.
RESULTS
No significant difference in vertebral body size of the atlas and axis was observed. A significant difference in vertebral canal size was observed between the animals. In biomechanical testing, the SMA-2 implant provided more stabilization, while the SMA-1 implant had lower strength than the conventional method using wires. The application time of wire was the longest, while that of SMA-1 was the shortest.
CLINICAL RELEVANCE
SMA implants provide comparable strength and demonstrate superior efficacy compared to conventional dorsal wire fixation of atlantoaxial stabilization. Therefore, SMA implants can be an effective surgical option for AAI.
Topics: Rabbits; Dogs; Animals; Shape Memory Alloys; Atlanto-Axial Joint; Joint Instability; Ligaments; Cadaver; Dog Diseases
PubMed: 37591491
DOI: 10.2460/ajvr.23.07.0158 -
Journal of Clinical Medicine Dec 2023In a multilevel cervical laminoplasty operation for patients with cervical spondylotic myelopathy (CSM), a partial or complete C3 laminectomy may be performed at the...
INTRODUCTION
In a multilevel cervical laminoplasty operation for patients with cervical spondylotic myelopathy (CSM), a partial or complete C3 laminectomy may be performed at the upper level instead of a C3 plated laminoplasty. It is unknown whether C3 technique above the laminoplasty affects loss of cervical lordosis or range of motion.
METHODS
Patients undergoing multilevel laminoplasty of the cervical spine (C3-C6/C7) at a single institution were retrospectively reviewed. Patients were divided into two cohorts based on surgical technique at C3: C3-C6/C7 plated laminoplasty ("C3 laminoplasty only", N = 61), C3 partial or complete laminectomy, plus C4-C6/C7 plated laminoplasty (N = 39). All patients had at least 1-year postoperative X-ray treatment.
RESULTS
Of 100 total patients, C3 laminoplasty and C3 laminectomy were equivalent in all demographic data, except for age (66.4 vs. 59.4 years, = 0.012). None of the preoperative radiographic parameters differed between the C3 laminoplasty and C3 laminectomy cohorts: cervical lordosis (13.1° vs. 11.1°, = 0.259), T1 slope (32.9° vs. 29.2°, = 0.072), T1 slope-cervical lordosis (19.8° vs. 18.6°, = 0.485), or cervical sagittal vertical axis (3.1 cm vs. 2.7 cm, = 0.193). None of the postoperative radiographic parameters differed between the C3 laminoplasty and C3 laminectomy cohorts: cervical lordosis (9.4° vs. 11.2°, = 0.369), T1 slope-cervical lordosis (21.7° vs. 18.1°, = 0.126), to cervical sagittal vertical axis (3.3 cm vs. 3.6 cm, = 0.479). In the total cohort, 31% had loss of cervical lordosis >5°. Loss of lordosis reached 5-10° (mild change) in 13% of patients and >10° (moderate change) in 18% of patients. C3 laminoplasty and C3 laminectomy cohorts did not differ with respect to no change (<5°: 65.6% vs. 74.3%, respectively), mild change (5-10°: 14.8% vs. 10.3%), and moderate change (>10°: 19.7% vs. 15.4%) in cervical lordosis, = 0.644. When controlling for age, ordinal regression showed that surgical technique at C3 did not increase the odds of postoperative loss of cervical lordosis. C3 laminectomy versus C3 laminoplasty did not differ in the postoperative range of motion on cervical flexion-extension X-rays (23.9° vs. 21.7°, = 0.451, N = 91).
CONCLUSION
There was no difference in postoperative loss of cervical lordosis or postoperative range of motion in patients who underwent either C3-C6/C7 plated laminoplasty or C3 laminectomy plus C4-C6/C7 plated laminoplasty.
PubMed: 38137663
DOI: 10.3390/jcm12247594 -
Journal of Orthopaedic Surgery and... Apr 2024Contiguous two-segment cervical disc arthroplasty (CDA) is safe and effective, while post-operative radiographic change is poorly understood. We aimed to clarify the...
BACKGROUND
Contiguous two-segment cervical disc arthroplasty (CDA) is safe and effective, while post-operative radiographic change is poorly understood. We aimed to clarify the morphological change of the three vertebral bodies operated on.
METHODS
Patients admitted between 2015 and 2020 underwent contiguous two-level Prestige LP CDA were included. The follow-up was divided into immediate post-operation (≤ 1 week), early (≤ 6 months), and last follow-up (≥ 12 months). Clinical outcomes were measured by Japanese Orthopedic Association (JOA) score, visual analogue score (VAS), and neck disability index (NDI). Radiographic parameters on lateral radiographs included sagittal area, anterior-posterior diameters (superior, inferior endplate length, and waist length), and anterior and posterior heights. Sagittal parameters included disc angle, Cobb angle, range of motion, T1 slope, and C2-C7 sagittal vertical axis. Heterotopic ossification (HO) and anterior bone loss (ABL) were recorded.
RESULTS
78 patients were included. Clinical outcomes significantly improved. Of the three operation-related vertebrae, only middle vertebra decreased significantly in sagittal area at early follow-up. The four endplates that directly meet implants experienced significant early loss in length. Sagittal parameters were kept within an acceptable range. Both segments had a higher class of HO at last follow-up. More ABL happened to middle vertebra. The incidence and degree of ABL were higher for the endplates on middle vertebra only at early follow-up.
CONCLUSION
Our findings indicated that after contiguous two-segment CDA, middle vertebra had a distinguishing morphological changing pattern that could be due to ABL, which deserves careful consideration before and during surgery.
Topics: Humans; Arthroplasty; Spine; Orthopedics; Vertebral Body; Bone Diseases, Metabolic
PubMed: 38610023
DOI: 10.1186/s13018-024-04663-6 -
Scientific Reports Jun 2024In forensic commingled contexts, when the disarticulation occurs uniquely at the atlantoaxial joint, the correct match of atlas and axis may lead to the desirable...
In forensic commingled contexts, when the disarticulation occurs uniquely at the atlantoaxial joint, the correct match of atlas and axis may lead to the desirable assembly of the entire body. Notwithstanding the importance of this joint in such scenarios, no study has so far explored three-dimensional (3D) methodologies to match these two adjoining bones. In the present study, we investigated the potential of re-associating atlas and axis through 3D-3D superimposition by testing their articular surfaces congruency in terms of point-to-point distance (Root Mean Square, RMS). We analysed vertebrae either from the same individual (match) and from different individuals (mismatch). The RMS distance values were assessed for both groups (matches and mismatches) and a threshold value was determined to discriminate matches with a sensitivity of 100%. The atlas and the corresponding axis from 41 documented skeletons (18 males and 23 females), in addition to unpaired elements (the atlas or the axis) from 5 individuals, were superimposed, resulting in 41 matches and 1851 mismatches (joining and non-joining elements). No sex-related significant differences were found in matches and mismatches (p = 0.270 and p = 0.210, respectively), allowing to pool together the two sexes in each group. RMS values ranged between 0.41 to 0.77 mm for matches and between 0.37 and 2.18 mm for mismatches. Significant differences were found comparing the two groups (p < 0.001) and the highest RMS of matches (0.77 mm) was used as the discriminative value that provided a sensitivity of 100% and a specificity of 41%. In conclusion, the 3D-3D superimposition of the atlanto-axial articular facets cannot be considered as a re-association method per se, but rather as a screening one. However, further research on the validation of the 3D approach and on its application to other joints might provide clues to the complex topic of the reassociation of crucial adjoining bones.
Topics: Humans; Male; Female; Imaging, Three-Dimensional; Cervical Atlas; Adult; Middle Aged; Axis, Cervical Vertebra; Atlanto-Axial Joint; Forensic Anthropology; Aged
PubMed: 38849396
DOI: 10.1038/s41598-024-63029-4 -
Journal of Korean Neurosurgical Society Jan 2024The integrity of the high cervical spine, the transition zone from the brainstem to the spinal cord, is crucial for survival and daily life. The region protects the...
The integrity of the high cervical spine, the transition zone from the brainstem to the spinal cord, is crucial for survival and daily life. The region protects the enclosed neurovascular structure and allows a substantial portion of the head motion. Injuries of the high cervical spine are frequent, and the fractures of the C2 vertebra account for approximately 17-25% of acute cervical fractures. We review the two major types of C2 vertebral fractures, odontoid fracture and Hangman's fracture. For both types of fractures, favorable outcomes could be obtained if the delicately selected conservative treatment is performed. In odontoid fractures, as the most common fracture on the C2 vertebrae, anterior screw fixation is considered first for type II fractures, and C1-2 fusion is suggested when nonunion is a concern or occurs. Hangman's fractures are the second most common fracture. Many stable extension type I and II fractures can be treated with external immobilization, whereas the predominant flexion type IIA and III fractures require surgical stabilization. No result proves that either anterior or posterior surgery is superior, and the surgeon should decide on the surgical method after careful consideration according to each clinical situation. This review will briefly describe the basic principles and current treatment concepts of C2 fractures.
PubMed: 37461838
DOI: 10.3340/jkns.2023.0098 -
Scientific Reports Oct 2023The aim of this study was to compare in-hospital mortality of three procedures -halo-vest immobilization, anterior spinal fixation (ASF), and posterior spinal...
The aim of this study was to compare in-hospital mortality of three procedures -halo-vest immobilization, anterior spinal fixation (ASF), and posterior spinal fixation (PSF)- in the treatment of elderly patients with isolated C2 odontoid fracture. We extracted data for elderly patients who were admitted with C2 odontoid fracture and treated with at least one of the three procedures (halo-vest immobilization, ASF, or PSF) during hospitalization. We conducted a generalized propensity score-based matching weight analysis to compare in-hospital mortality among the three procedures. We further investigated independent risk factors for in-hospital death. The study involved 891 patients (halo-vest, n = 463; ASF, n = 74; and PSF, n = 354) with a mean age of 78 years. In-hospital death occurred in 45 (5.1%) patients. Treatment type was not significantly associated with in-hospital mortality. Male sex (odds ratio 2.98; 95% confidence interval 1.32-6.73; p = 0.009) and a Charlson comorbidity index of ≥ 3 (odds ratio 9.18; 95% confidence interval 3.25-25.92; p < 0.001) were independent risk factors for in-hospital mortality. In conclusion, treatment type was not significantly associated with in-hospital mortality in elderly patients with isolated C2 odontoid fracture. Halo-vest immobilization can help to avoid adverse events in patients with C2 odontoid fracture who are considered less suitable for surgical treatment.
Topics: Humans; Male; Aged; Hospital Mortality; Odontoid Process; Spinal Fractures; Spinal Fusion; Fractures, Bone; Risk Factors; Treatment Outcome
PubMed: 37864100
DOI: 10.1038/s41598-023-45180-6 -
Spine Deformity Mar 2024To define the prevalence, characteristics, and treatment approach for proximal junction failure secondary to odontoid fractures in patients with prior C2-pelvis...
PURPOSE
To define the prevalence, characteristics, and treatment approach for proximal junction failure secondary to odontoid fractures in patients with prior C2-pelvis posterior instrumented fusions (PSF).
METHODS
A single institution's database was queried for multi-level fusions (6+ levels), including a cervical component. Posterior instrumentation from C2-pelvis and minimum 6-month follow-up was inclusion criteria. Patients who sustained dens fractures were identified; each fracture was subdivided based on Anderson & D'Alonzo and Grauer's classifications. Comparisons between the groups were performed using Chi-square and T tests.
RESULTS
80 patients (71.3% female; average age 68.1 ± 8.1 years; 45.0% osteoporosis) were included. Average follow-up was 59.8 ± 42.7 months. Six patients (7.5%) suffered an odontoid fracture post-operatively. Cause of fracture in all patients was a mechanical fall. Average time to fracture was 23 ± 23.1 months. Average follow-up after initiation of fracture management was 5.84 ± 4 years (minimum 1 year). Three patients sustained type IIA fractures one of which had a concomitant unilateral C2 pars fracture. Three patients sustained comminuted type III fractures with concomitant unilateral C2 pars fractures. Initial treatment included operative care in 2 patients, and an attempt at non-operative care in 4. Non-operative care failed in 75% of patients who ultimately required revision with proximal extension. All patients with a concomitant pars fracture had failure of non-operative care. Patients with an intact pars were more stable, but 50% required revision for pain.
CONCLUSIONS
In this 11-year experience at a single institution, the prevalence of odontoid fractures above a C2-pelvis PSF was 7.5%. Fracture morphology varied, but 50% were complex, comminuted C2 body fractures with concomitant pars fractures. While nonoperative management may be suitable for type II fractures with simple patterns, more complex and unstable fractures likely benefit from upfront surgical intervention to prevent fracture displacement and neural compression. As all fractures occurred secondary to a mechanical fall, inpatient and community measures aimed to minimize risk and prevent mechanical falls would be beneficial in this high-risk group.
Topics: Humans; Female; Middle Aged; Aged; Male; Odontoid Process; Spinal Fractures; Fracture Fixation, Internal; Fractures, Bone; Pelvis
PubMed: 38157096
DOI: 10.1007/s43390-023-00800-z -
Clinical Spine Surgery Feb 2024National Trauma Data Bank (NTDB) review and propensity-matched analysis.
STUDY DESIGN
National Trauma Data Bank (NTDB) review and propensity-matched analysis.
OBJECTIVE
To evaluate differences in clinical outcomes by operative management.
SUMMARY OF BACKGROUND DATA
Odontoid type II fractures are the most prevalent cervical fracture. Operative intervention on these fractures is frequently debated; surgical risks are compounded by clinical severity, patient age, and comorbidities.
METHODS
This registry review included index admissions for odontoid type II fractures [International Classification of Diseases (ICD)-10 codes beginning with S12.11] from 1/1/2017 to 1/1/2020; patients who died in the emergency department (ED) were excluded. Propensity score techniques were used to match patients 1:1 by surgical management, using a caliper distance of 0.05, after matching on the following covariates that differed significantly between surgical and nonsurgical patients: age, sex, race, cause of injury, transfer status, injury severity score, ED Glasgow coma score, ED systolic blood pressure, presence of transverse ligamentous injury, cervical dislocation, and 8 comorbidities. The following outcomes were analyzed with McNemar tests and Wilcoxon signed-rank tests: near-term survival (discharged from the hospital to locations other than morgue or hospice), intensive care unit (ICU) admission, hospital complications, median hospital length of stay (LOS), and median ICU LOS.
RESULTS
There were 16,607 patients, 2916 (17.6%) were operatively managed and 13,691 were nonoperatively managed. Before matching, survival was greater for patients managed operatively compared with nonoperatively (95.0% vs. 88.2%). The matched population consisted of 5334 patients: 2667 patients in the operative group (91.5% of this population) and 2667 well-matched patients in the nonoperative group. After matching, there was a survival benefit for patients who were operatively managed compared with nonoperative management (94.8% vs. 91.4% P <0.001). However, operative management was associated with greater development of complications, ICU admission, and longer hospital and ICU LOS.
CONCLUSION
Compared with nonoperative management, operative management demonstrated a significant near-term survival benefit for patients with odontoid type II fractures in select patients.
LEVEL OF EVIDENCE
III.
Topics: Humans; Treatment Outcome; Odontoid Process; Spinal Fractures; Comorbidity; Intensive Care Units; Length of Stay; Retrospective Studies
PubMed: 37651564
DOI: 10.1097/BSD.0000000000001511 -
Indian Pediatrics May 2024
Topics: Humans; Atlanto-Axial Joint; Joint Dislocations; Odontoid Process; Pruritus
PubMed: 38554007
DOI: No ID Found -
Journal of Orthopaedic Surgery and... Jan 2024To assess whether there is a difference between measurements of odontoid incidence (OI) and other cervical sagittal parameters by X-ray radiography and those by supine...
OBJECTIVE
To assess whether there is a difference between measurements of odontoid incidence (OI) and other cervical sagittal parameters by X-ray radiography and those by supine magnetic resonance imaging (MRI).
METHODS
Standing X-ray and supine MRI images of 42 healthy subjects were retrospectively analyzed. Surgimap software was employed to measure cervical sagittal parameters including OI, odontoid tilt (OT), C2 slope (C2S), C0-2 angle, C2-7 angle, T1 slope (T1S) and T1S-cervical lordosis (CL). Paired samples t-test was applied to determine the difference between parameters measured by standing X-ray and those by supine MRI. In addition, the statistical correlation between the parameters were compared. The prediction of CL was performed and validated using the formula CL = 0.36 × OI - 0.67 × OT - 0.69 × T1S.
RESULTS
Significant correlations and differences were found between cervical sagittal parameters determined by X-ray and those by MRI. OI was verified to be a constant anatomic parameter and the formula CL = 0.36 × OI - 0.67 × OT - 0.69 × T1S can be used to predict CL in cervical sagittal parameters.
CONCLUSIONS
OI is verified as a constant anatomic parameter, demonstrating the necessity of a combined assessment of cervical sagittal balance by using standing X-ray and supine MRI. The formula CL = 0.36 × OI - 0.67 × OT - 0.69 × T1S can be applied to predict CL in cervical sagittal parameters.
Topics: Humans; Retrospective Studies; Odontoid Process; Cervical Vertebrae; Radiography; Magnetic Resonance Imaging; Lordosis
PubMed: 38218851
DOI: 10.1186/s13018-024-04542-0