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European Radiology Aug 2023To introduce novel parameters in determining directions of os odontoideum (OO) with atlantoaxial displacement (AAD) and compensations of cervical sagittal alignment...
Axial superior facet slope may determine anterior or posterior atlantoaxial displacement secondary to os odontoideum and compensatory mechanisms of the atlantooccipital joint and subaxial cervical spine.
OBJECTIVE
To introduce novel parameters in determining directions of os odontoideum (OO) with atlantoaxial displacement (AAD) and compensations of cervical sagittal alignment after displacement.
METHODS
Analysis was performed on 96 cases receiving surgeries for upper cervical myelopathy caused by OO with AAD from 2011 to 2021. Twenty-four patients were included in the OO group and divided into the OO-anterior displacement (AD) group and the OO-posterior displacement (PD) group by displacement. Seventy-two patients were included as the control (Ctrl) group and divided into Ctrl-positive (Ctrl-P) group and Ctrl-negative (Ctrl-N) group by axial superior facet slope (ASFS) in a neutral position. ASFS, the sum of C2 slope (C2S) and axial superior facet endplate angle (ASFEA), was measured and calculated by combining cervical supine CT with standing X-ray. Cervical sagittal parameters were measured to analyse the atlantoaxial facet and compensations after AAD.
RESULTS
Atlas inferior facet angle (AIFA), ASFS, and ASFEA in Ctrl-P significantly differed from OO-AD.C0-C1, C1-C2, C0-C2, C2-C7, C2-C7 SVA, and C2S in Ctrl-P significant differed from the OO-AD group. C2-C7 SVA and C2S in Ctrl-N significantly were smaller than the OO-PD group. C1-C2 correlated with C0-C1 and C2-C7 negatively in the OO group. Slight kyphosis of C1-C2 in OO-AD was compared with lordosis of C1-C2 in Ctrl-P, inducing increased extension of C0-C1 and C2-C7. Mildly increased lordosis of C1-C2 in OO-PD was compared with C1-C2 in Ctrl-N, triggering augmented flexion of C0-C1 and C2-C7.
CONCLUSION
ASFS was vital in determining directions of OO with AAD and explaining compensations. ASFS and ASFEA could provide pre- and intraoperative guidelines.
KEY POINTS
• ASFS may determine the directions and compensatory mechanisms of AAD secondary to OO. • ASFS could be achieved by the sum of ASFEA and C2S.
Topics: Humans; Lordosis; Cervical Vertebrae; Kyphosis; Neck; Axis, Cervical Vertebra; Retrospective Studies
PubMed: 36947189
DOI: 10.1007/s00330-023-09544-w -
Radiology Case Reports May 2023Epidural angiolipoma is a rare benign tumor consisting of mature adipocytes, blood sinuses, capillaries, and small blood vessels. It constitutes about 0.04%-1.2% of...
Epidural angiolipoma is a rare benign tumor consisting of mature adipocytes, blood sinuses, capillaries, and small blood vessels. It constitutes about 0.04%-1.2% of spinal axis tumors and about 2%-3% of extradural spinal tumors. We report a case of thoracic epidural angiolipoma and review the literature. We describe a 42-year-old woman who had weakness and numbness in her lower extremities prior to diagnosis and had an onset of approximately 10 months. The patient was misdiagnosed as schwannoma on preoperative imaging, possibly because neurogenous tumor is the most common intramedullary subdural tumor, and the lesion grew into bilateral intervertebral foramina. However, the lesion demonstrated high signal on the T2-weighted and T2 fat suppression sequences, and the linear low signal at the lesion edge was ignored, leading to misdiagnosis. The patient underwent posterior thoracic 4-6 laminectomy, pathectomy, and spinal decompression/vertebroplasty under general anesthesia. The final pathologic diagnosis was intradural epidural angiolipoma of the thoracic vertebra. Spinal epidural angiolipoma is a rare benign tumor that occurs frequently in middle-aged women and is mostly located on the dorsal side of the thoracic spinal canal. Magnetic resonance imaging findings of spinal epidural angiolipoma depend on the ratio of fat to blood vessels. Most angiolipomas show equal or high signal on T1-weighted images and high intensity on T2-weighted images, with significant enhancement after injection of gadolinium. The treatment of spinal epidural angiolipoma is complete surgical resection with good prognosis.
PubMed: 36895895
DOI: 10.1016/j.radcr.2023.01.095 -
BMC Musculoskeletal Disorders Mar 2023This study represents the first finite element (FE) analysis of long-instrumented spinal fusion from the thoracic vertebrae to the pelvis in the context of adult spinal...
BACKGROUND
This study represents the first finite element (FE) analysis of long-instrumented spinal fusion from the thoracic vertebrae to the pelvis in the context of adult spinal deformity (ASD) with osteoporosis. We aimed to evaluate the von Mises stress in long spinal instrumentation for models that differ in terms of spinal balance, fusion length, and implant type.
METHODS
In this three-dimensional FE analysis, FE models were developed based on computed tomography images from a patient with osteoporosis. The von Mises stress was compared for three different sagittal vertical axes (SVAs) (0, 50, and 100 mm), two different fusion lengths (from the pelvis to the second [T2-S2AI] or 10th thoracic vertebra [T10-S2AI]), and two different types of implants (pedicle screw or transverse hook) in the upper instrumented vertebra (UIV). We created 12 models based on combinations of these conditions.
RESULTS
The overall von Mises stress was 3.1 times higher on the vertebrae and 3.9 times higher on implants for the 50-mm SVA models than that for the 0-mm SVA models. Similarly, the values were 5.0 times higher on the vertebrae and 6.9 times higher on implants for the 100-mm SVA models than that for the 0-mm SVA models. Higher SVA was associated with greater stress below the fourth lumbar vertebrae and implants. In the T2-S2AI models, the peaks of vertebral stress were observed at the UIV, at the apex of kyphosis, and below the lower lumbar spine. In the T10-S2AI models, the peaks of stress were observed at the UIV and below the lower lumbar region. The von Mises stress in the UIV was also higher for the screw models than for the hook models.
CONCLUSION
Higher SVA is associated with greater von Mises stress on the vertebrae and implants. The stress on the UIV is greater for the T10-S2AI models than for the T2-S2AI models. Using transverse hooks instead of screws at the UIV may reduce stress in patients with osteoporosis.
Topics: Adult; Humans; Finite Element Analysis; Spinal Fusion; Kyphosis; Lumbar Vertebrae; Thoracic Vertebrae; Pedicle Screws; Osteoporosis; Retrospective Studies
PubMed: 36890531
DOI: 10.1186/s12891-023-06290-4 -
Calcified Tissue International May 2023The odontoid process (dens) of the second cervical vertebra (axis) is prone to fracture. While the importance of its skeletal integrity has been previously noted,...
The odontoid process (dens) of the second cervical vertebra (axis) is prone to fracture. While the importance of its skeletal integrity has been previously noted, representative three-dimensional microarchitecture analyses in humans are not available. This study aimed to determine the bone microarchitecture of the axis using high-resolution quantitative computed tomography (HR-pQCT) and to derive clinical implications for the occurrence and treatment of axis fractures. For initial clinical reference, the apparent density of the axis was determined based on clinical computed tomography (CT) images in patients without and with fractures of the axis. Subsequently, 28 human axes (female 50%) obtained at autopsy were analyzed by HR-pQCT. Analyses were performed in three different regions corresponding to zones I (tip of dens), II (base of dens), and III (corpus axis) of the Anderson and D'Alonzo classification. Lower apparent densities based on clinical CT data were detected in zone II and III compared to zone I in both the group without and with fracture. In the autopsy specimens, cortical thickness and bone volume fraction decreased continuously from zone I to zone III. Trabecular and cortical tissue mineral density was lowest in zone III, with no differences between zones I and II. In conclusion, our clinical and high-resolution ex vivo imaging data highlight a marked regional heterogeneity of bone microarchitecture, with poor cortical and trabecular properties near the dens base. These results may partly explain why zones II and III are at high risk of fracture and osteosynthesis failure.
Topics: Humans; Female; Fractures, Bone; Bone and Bones; Odontoid Process; Tomography, X-Ray Computed; Autopsy; Bone Density; Radius
PubMed: 36826480
DOI: 10.1007/s00223-023-01070-7 -
BMC Surgery Feb 2023The aim of this study was to evaluate the applicability and advantages of intraoperative imaging using a 3D flat panel in the treatment of C1/2 instabilities.
BACKGROUND
The aim of this study was to evaluate the applicability and advantages of intraoperative imaging using a 3D flat panel in the treatment of C1/2 instabilities.
MATERIALS
Prospective single-centered study including surgeries at the upper cervical spine between 06/2016 and 12/2018. Intraoperatively thin K-wires were placed under 2D fluoroscopic control. Then an intraoperative 3D-scan was carried out. The image quality was assessed based on a numeric analogue scale (NAS) from 0 to 10 (0 = worst quality, 10 = perfect quality) and the time for the 3D-scan was measured. Additionally, the wire positions were evaluated regarding malpositions.
RESULTS
A total of 58 patients were included (33f, 25 m, average age 75.2 years, r.:18-95) with pathologies of C2: 45 type II fractures according to Anderson/D'Alonzo with or without arthrosis of C1/2, 2 Unhappy triad of C1/2 (Odontoid fracture Type II, anterior or posterior C1 arch-fracture, Arthrosis C1/2) 4 pathological fractures, 3 pseudarthroses, 3 instabilities of C1/2 because of rheumatoid arthritis, 1 C2 arch fracture). 36 patients were treated from anterior [29 AOTAF (combined anterior odontoid and transarticular C1/2 screw fixation), 6 lag screws, 1 cement augmented lag screw] and 22 patients from posterior (regarding to Goel/Harms). The median image quality was 8.2 (r.: 6-10). In 41 patients (70.7%) the image quality was 8 or higher and in none of the patients below 6. All of those 17 patients the image quality below 8 (NAS 7 = 16; 27.6%, NAS 6 = 1, 1.7%), had dental implants. A total of 148 wires were analyzed. 133 (89.9%) showed a correct positioning. In the other 15 (10.1%) cases a repositioning had to be done (n = 8; 5.4%) or it had to be drawn back (n = 7; 4.7%). A repositioning was possible in all cases. The implementation of an intraoperative 3D-Scan took an average of 267 s (r.: 232-310 s). No technical problems occurred.
CONCLUSION
Intraoperative 3D imaging in the upper cervical spine is fast and easy to perform with sufficient image quality in all patients. Potential malposition of the primary screw canal can be detected by initial wire positioning before the Scan. The intraoperative correction was possible in all patients. Trial registration German Trials Register (Registered 10 August 2021, DRKS00026644-Trial registration: German Trials Register (Registered 10 August 2021, DRKS00026644- https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00026644 ).
Topics: Aged; Humans; Bone Cements; Cervical Vertebrae; Fractures, Bone; Odontoid Process; Osteoarthritis; Prospective Studies; Spinal Fractures; Spinal Fusion
PubMed: 36803456
DOI: 10.1186/s12893-023-01934-7 -
Journal of Orthopaedic Surgery and... Feb 2023The assessment of bone density is of great importance nowadays due to the increasing age of patients. Especially in regard to the surgical stabilization of the spine,...
INTRODUCTION
The assessment of bone density is of great importance nowadays due to the increasing age of patients. Especially in regard to the surgical stabilization of the spine, the assessment of bone density is important for therapeutic decision making. The aim of this work was to record trabecular bone density values using Hounsfield units of the second cervical vertebra.
MATERIAL AND METHODS
The study is a monocentric retrospective data analysis of 198 patients who received contrast-enhanced polytrauma computed tomography in a period of two years at a maximum care hospital. Hounsfield units were measured in three different regions within the C2: dens, transition area between dens and vertebral body and vertebral body. The measured Hounsfield units were converted into bone density values using a validated formula.
RESULTS
A total of 198 patients were included. The median bone density varied in different regions of all measured C2 vertebrae: in the dens axis, C2 transition area between dens and vertebral body, and in the vertebral body bone densities were 302.79 mg/cm, 160.08 mg/cm, and 240.31 mg/cm, respectively. The transition area from dens axis to corpus had statistically significant lower bone density values compared to the other regions (p < 0.001). There was a decrease in bone density values after age 50 years in both men and women (p < 0.001).
CONCLUSIONS
The transitional area from dens axis to corpus showed statistically significant lower bone density values compared to the adjacent regions (p < 0.001). This area seems to be a predilection site for fractures of the 2nd cervical vertebra, which is why special attention should be paid here in radiological diagnostics after a trauma.
Topics: Male; Humans; Female; Middle Aged; Bone Density; Retrospective Studies; Spine; Tomography, X-Ray Computed; Radiography; Spinal Fractures
PubMed: 36765379
DOI: 10.1186/s13018-023-03560-8 -
Journal of Neurosciences in Rural... 2022A congenital abnormality of the posterior element of the axis (C2) vertebra is extremely unusual, with just a few occurrences documented in the literature. The majority...
A congenital abnormality of the posterior element of the axis (C2) vertebra is extremely unusual, with just a few occurrences documented in the literature. The majority of individuals have no symptoms and are discovered by chance on plain radiography for neck discomfort, radiculopathy, or trauma. We describe a case of a 13-year-old boy who was born without the posterior element of the C2 vertebrae, resulting in C2-C3 spinal instability and compressive myelopathy.
PubMed: 36743756
DOI: 10.25259/JNRP-2021-11-41-R1-(2214) -
Frontiers in Surgery 2022The objective of the study is to establish a new parameter that can be clearly measured on x-ray images to complement the description of the sagittal alignment of the...
OBJECTIVE
The objective of the study is to establish a new parameter that can be clearly measured on x-ray images to complement the description of the sagittal alignment of the craniocervical junction. The authors anticipate that this new parameter will enhance surgeons' understanding of the sagittal alignment of the craniocervical junction and play a positive role in the guidance of intraoperative reduction and in the evaluation of postoperative outcomes of patients with atlantoaxial instability.
METHODS
From November 2018 to June 2020, a total of 159 asymptomatic subjects who underwent frontal and lateral cervical x-ray examination in the Second Affiliated Hospital of Soochow University were included in the study. Age, gender, previous spinal trauma, and disease history of each subject were recorded. After screening, 127 effective samples were finally obtained. When taking lateral cervical radiographs, all subjects placed their neck in a neutral position and looked straight ahead with both eyes. On the obtained lateral x-ray images, a straight line was drawn from the radix to the anterior clinoid process; another line was made along the posterior edge of the C2 vertebral body; and the angle between the two lines was measured, which was defined as the "horizontal view-axial angle." The angle formed by the tangent of the posterior edge of the C2 vertebra and C7 vertebral body is the "C2-C7 angle," which was used to describe the curvature of the lower cervical vertebra. The normal range of horizontal view-axial angle and its relationship with C2-7 angle were evaluated.
RESULTS
The average C2-C7 angle of male subjects was (14.0° ± 7.4°), while that of female subjects was (11.09° ± 7.36°). The average horizontal view-axial angle of male subjects was (92.79° ± 4.52°), and that of female subjects was (94.29° ± 4.50°). Pearson correlation test showed that there was a significant negative correlation between horizontal view-axis angle and C2-C7 angle.
CONCLUSIONS
For patients with atlantoaxial instability diseases, the horizontal view-axis angle is expected to be a sagittal parameter to guide the intraoperative reduction and evaluate postoperative outcomes.
PubMed: 36684255
DOI: 10.3389/fsurg.2022.947462 -
Journal of Orthopaedic Surgery and... Jan 2023There are many classification systems for atlantoaxial dislocation (AAD). Among these systems, the definitions of irreducible AAD remain vague, and its treatments are...
BACKGROUND
There are many classification systems for atlantoaxial dislocation (AAD). Among these systems, the definitions of irreducible AAD remain vague, and its treatments are not unified.
OBJECTIVE
To explore the surgical strategies and efficacy for the treatment of os odontoideum (OO) with AAD.
METHODS
The clinical data of 56 OO patients with AAD who underwent surgery from January 2017 to June 2021 were retrospectively analyzed. AAD was classified into four types, Type I and type II were treated with posterior fixation and fusion. Type III received posterior fixation and fusion after irreducible dislocations were converted to reducible dislocations by translateral mass release or transoral release. Type IV required transoral release for conversion into reducible dislocations before posterior fixation and fusion. The operation time, blood loss, and complications were recorded. The preoperative and postoperative neurological function changes were assessed using the Japanese Orthopedic Association (JOA) score. Postoperative fusion status was assessed by X-ray.
RESULTS
There were 40 cases of type I-II, 14 cases of type III, and two cases of type IV AAD. The operation times of single posterior fixation and fusion, combined translateral mass release and combined transoral release were 130.52 ± 37.12 min, 151.11 ± 16.91 min and 188.57 ± 44.13 min, the blood loss were 162.63 ± 58.27 mL, 235.56 ± 59.94 mL, 414.29 ± 33.91 mL, respectively. One patient with type III died, one with type III underwent revision surgery due to infection, and three patients with type I had further neurological deterioration after operation. fifty-five patients were followed up for 12-24 months. The follow-up results showed that enough decompression was achieved and that fixation and fusion were effective. The JOA score increased from 9.58 ± 1.84 points preoperative to 13.09 ± 2.68 points at 3 months after operation, 14.07 ± 2.83 points at 6 months and 14.25 ± 2.34 at 12 months after operation, all significant differences compared with preoperative results (P < 0.05).
CONCLUSION
OO patients with irreducible AAD can be treated by translateral mass release or transoral release combined with posterior fixation and fusion, while some of those with bony fusion can be treated by transoral release combined with posterior fixation and fusion.
Topics: Humans; Retrospective Studies; Atlanto-Axial Joint; Axis, Cervical Vertebra; Joint Dislocations; Radiography; Spinal Injuries; Spinal Fusion; Treatment Outcome
PubMed: 36639761
DOI: 10.1186/s13018-023-03517-x -
Acta Medica Okayama Dec 2022We provide the first report of successful salvage surgery for a post-C1 laminectomy symptomatic recurrence of a retro-odontoid pseudotumor (ROP) that caused myelopathy....
We provide the first report of successful salvage surgery for a post-C1 laminectomy symptomatic recurrence of a retro-odontoid pseudotumor (ROP) that caused myelopathy. The 72-year-old Japanese woman presented with an ROP causing symptomatic cervical myelopathy. With ultrasonography support, we performed the enucleation of the ROP via a transdural approach and fusion surgery for the recurrence of the mass. At the final observation 2-year post-surgery, MRI demonstrated the mass's regression and spinal cord decompression, and the patient's symptoms had improved. Our strategy is an effective option for a symptomatic recurrence of ROP.
Topics: Female; Humans; Aged; Laminectomy; Odontoid Process; Spinal Cord Diseases; Magnetic Resonance Imaging; Decompression, Surgical
PubMed: 36549779
DOI: 10.18926/AMO/64127