Posterior Arch Research Articles

Magnetic resonance imaging (MRI) vs. computed tomography (CT) in the diagnosis and classification of spondylolysis and spondylolisthesis-a narrative review.

Spondylolysis is a lysis of the pars interarticularis, a component of the posterior arch of the vertebral body, in the face of repeated overuse and stress phenomena generally associated with sports in children and adolescent patients. This entity is one of the most common causes of low back pain in this age group. The diagnosis can be made using various imaging techniques, with computed tomography (CT) being considered the gold standard, as it provides the best visualization of the fracture, its extension and orientation, as well as an assessment of the entire bony skeleton. It is essential to understand the physiopathology and natural evolution of the disease as well as to know the typical findings of this disease in each imaging technique in order to be able to make a diagnosis in early stages of the disease. In this paper, we will review the clinical manifestations and typical radiologic findings of spondylolisthesis and spondylolisthesis, which allow a correct and early diagnosis. The literature available in English from 1976 (when the first publications on the diagnosis of this pathology appeared) up to the present day has been used for this review. In this review we will review the etiology, etiopathogenesis and natural evolution of spondylolysis and spondylolisthesis, we will place special emphasis on the radiological findings in magnetic resonance imaging with a view to an early diagnosis that allows us to slow down the evolution of the disease in its initial stages and we will look at the advantages and disadvantages of each technique. Spondylolysis is an increasingly frequent entity due to the increase in sporting activity at younger and younger ages, so radiologists should consider its existence in patients with low back pain and know the radiological signs that allow us to make an early diagnosis.

Evaluation of the Effect of Pre-bent Z-shaped Titanium Plate on Narrowing of Zygomatic Arch in L-shaped Reduction Malarplasty

Objective: Pre-bent titanium plates are widely used for internal fixation in L-shaped zygomatic reduction. The aim is to evaluate the effect of pre-bent Z-shaped titanium plate on the narrowing of the zygomatic arch in L-shaped reduction malarplasty. Methods: Thirty cosmetic female patients were selected and scanned using computed tomography (CT). The CT images of pre-operation (T1) and post-operation(T2) were re-established through MIMICS26.0 (Materialise). After the 2 images were registered based on the skull base, the narrowing distance (ZRN) at the posterior end of the free zygomatic arch, as well as the preoperative and postoperative cross-sectional dimensions of the zygomatic arch, were measured. The ZRN and the altitude of the pre-bent titanium plate (TA) were compared using an independent t test, and their correlation was also analyzed using the Pearson coefficient. The preoperative and postoperative longest diameter (L1) and shortest diameter (L2) of the posterior zygomatic arch were compared using a paired t test. Results: The TA was 3.80±0.82 mm and the ZRN was 3.21±0.82 mm. The difference value was 0.59±0.41 mm, which was statistically significant. TA showed a strong correlation with ZRN (r=0.916, P=0.002). The L1 and L2 of the zygomatic arch root were slightly reduced postoperatively. Conclusion: The pre-bent Z-shaped titanium plate does not completely correspond to the zygomatic arch narrowing distance in the actual application of L-shaped reduction malarplasty. However, it can control the narrowing distance of the zygomatic arch predictably, and achieve satisfactory surgical outcomes.

Vertebral cortical thickness and cortical bone density: an automated CT assessment - towards enhanced spine segmentation

ABSTRACT In this paper a non-invasive method using routine CT scan to assess the vertebral geometry through normalised Cortical Thickness (CTh) and Cortical Bone Density (CBD) is proposed. This paper aims to propose a new automated method to segment cortical bone and measure its thickness and local density. This method were then used as a tool to compare these parameters between different vertebra models (in-vivo, cadaver and swine) and vertebra levels. An automated technique to segment cortical bone was proposed, assuming a two Gaussian bone density distribution. 42 vertebrae (3 high-thoracic, 3 low-thoracic and 1 lumbar vertebra for each subject) from three sub-groups (human in-vivo, cadaver and swine) were investigated. In the human in-vivo sub-group, the vertebral level was shown to influence normalised CTh and CBD. The CBD was found uniform within all the functional areas of the vertebral body (p > 0.05), while the normalised CTh showed significant differences (p < 0.001). Both CBD and normalised CTh showed significantly different between the inferior articular processes area and the posterior arch area d (p < 0.02 *). In each of the three sub-groups (human in-vivo Vs cadaveric Vs swine), normalised CTh and CBD were found significantly different across most functional areas (p < 0.001 ***). The proposed method offers an automated and accurate way of measuring cortical thickness and cortical bone density. Vertebra level and vertebra function areas were found to have influences on both proposed cortical bone characteristics. The influence of the vertebral level and of the vertebral functional areas on normalised CTh and CBD were reported within in-vivo and two vertebral models. Such a methodology could be used as a tool for image-guided surgery.

The Efficacy of Naso-Alveolar Molding on Premaxilla Pushback and Dentoalveolar Changes in Patients With Bilateral Cleft Lip and Palate.

To evaluate the extent of naso-alveolar molding (NAM) in pushing the premaxilla posteriorly in patients with bilateral cleft lip and palate (BCLP). Naso-alveolar molding application in cleft lip and palate cases bridges the cleft gap and increases nasal tip projection. In BCLP, NAM potentially mobilizes the premaxilla posteriorly to allow tension-free primary lip closure. However, some patients with BCLP with NAM history still necessitate osteotomy during labioplasty, questioning the efficacy of NAM for BCLP management. This single-center retrospective study was conducted using medical records of nonsyndromic patients with BCLP. Twenty-six patients with BCLP were enrolled over a 5-year period with a history of NAM application before primary labioplasty. The changes in premaxilla width (P), anterior arch width (A), posterior arch width (R), and anteroposterior projection of the premaxilla (P'-A') were statistically analyzed at 2 time points: (1) at the start of NAM application (T1) and (2) after completion of NAM before surgery (T2). The average age at NAM initiation was 46.2 ± 40.4 days, and the average duration of NAM usage was 125.14 ± 62.94 days. A and P-A showed significant differences between T1 and T2 (P < 0.0001), whereas the rest did not show significant differences in value following NAM application (P > 0.05). Naso-alveolar molding successfully pushed back the premaxilla portion about 4.68 ± 2.83mm on average. Naso-alveolar molding can push back the premaxillary protrusion up to 5mm, which can serve as a cutoff point for the consideration of combined modalities. Prenatal diagnosis, counseling, and cleft education should be the benchmark in cleft centers to improve overall patient outcomes.

Incidence of Congenital Posterior Arch Defects of the Atlas in Chinese Population

To study the incidence of congenital posterior arch defects of the atlas and in combination with other congenital variations in the Chinese population. 1405 images of cervical three-dimensional computed tomography (3D CT) and 1284 images of head and cervical three-dimensional computed tomography angiography (3D CTA) were retrospectively reviewed, including images of 1539 males and 1150 females. These images of cervical 3D CT and head and cervical 3D CTA were obtained in the Department of Radiology of two hospitals, Second and Third People's Hospital of Jingzhou, China, from January 2020 to October 2023. And congenital posterior arch defects of the atlas were classified according to the criteria of Currarino et al. Congenital posterior arch defects of the atlas combined with other congenital variations including occipitalization of the atlas, the ponticulus posticus variation of the vertebral artery groove of the atlas, cervical fusion, and the transversal foramen of the atlas variant were also observed. A total of 2689 subjects were included in this study. The overall prevalence of congenital posterior arch defects of the atlas was 0.74% (20/2689). There was no statistically significant difference in incidence between males (0.78%,12/1539) and females (0.70%,8/1150) (P >0.05). Among all posterior defects, type A and B defects were found in 0.6% (16/2689) and 0.15% (4/2689) cases, respectively. There were no type C, D, and E defects and no anterior arch defects. But in 20 cases of congenital posterior arch defects of atlas, 40%(8/20) combined with other congenital variations including occipitalization of atlas in 4 type A cases, bilateral complete ponticus posticus variation of atlas vertebral groove in one type A case, C2-3 fusion in one type A case, coexistence of unilateral complete ponticulus posticus variation of the vertebral artery groove of the atlas and unilateral unclosed transverse foramen in one type B case, and coexistence of unilateral unclosed transverse foramen in one type A case. The incidence of congenital posterior arch defects of the atlas was low in Chinese population. There was no difference between males and females. Type A and B were the two major defects in Chinese population, and the prevalence of type A and B combined with other congenital cervical variations were higher than those of type C, D, and E.

Nasoalveolar Molding in Lately Presented Moderate to Severe Unilateral Cleft Lip and Palate Infants: Does it Add?

Alignment of the alveolar segments with early nasal cartilage tackling is the foundation upon which excellent surgical results are dependent. The purpose is to evaluate the short-term effect of triple combination of passive alveolar molding with early nasal molding augmented by controlled corrective power of lip tapping in lately presented moderate to severe unilateral complete cleft lip and palate infants. A prospective case series study was conducted in Plastic and Maxillofacial Surgery Department, Ain Shams University in collaboration with Orthodontics Department, from January 2021 till June 2023, 15 infants elder than 2 months till 6 months were enrolled in the study. Eight nasal anthropometric measurements ratios through 2-dimension assessment and 4 maxillary arch measurements ratios through 3-dimension assessment were recorded. Extraoral results revealed clinically and statistically decrease of nasal width, alar base width, alar base height ratios, and columellar angle, while increase of nasal height, nasal dome height, columellar length, and alar projection length ratios. Intraoral results revealed clinically and statistically decrease in cleft width with maintained posterior arch width and intercanine width. In conclusion, this triple combination helped in presurgical lessening the alveolar and nasal deformity of such elder infants in a shorter time in comparison with other conventional methods with lesser number of appointments decreasing burden of care to their families improving their compliance.

Differences in Cervical Spine Fractures in Patients Younger or Older Than 65 Years of Age: Implications for the Canadian C-Spine Rule.

There has been a distinction made in the 2001 Canadian C-Spine Rule regarding patients 65 and older and younger than 65 years of age as far as indications for cervical spine CT scanning. We sought to determine if there are differences in the symptoms, mechanisms of injury, fracture locations, and types that are still relevant in 2024. The institutional review board approved this retrospective study of cervical spine CT emergency department results from 2 hospitals in our health system after reviewing 5 years of data in patients experiencing trauma. In addition to the primary variable of age (younger than 65 years and 65 years and older), we looked at injury mechanism, fracture types, sites, symptoms, and operative or medical treatments. Because the demographics of our home site is different from most towns in the United States, we provide race/ethnicity data. Of 21,986 cervical spine CTs, 190/9455 (2.0%) participants 65 years of age and older and 199/12,531 (1.6%) participants younger than 65 years of age had fractures (total, 389/21,986, 1.8%). There were more cases of falls from standing (106, 55.8%) and falls from a height (46, 4.2%) in those 65 years and older and this mechanism was associated with a higher risk of C1 and C2 fractures (52, 27.4%; and 78, 41.1%, respectively). Among the C1 fractures, anterior and posterior arch fractures predominated (37, 19.5%). For C2 fractures, types 2 and 3 odontoid fractures (39, 20.5%; and 12, 6.3%) were more common in the older cohort. Motor vehicle collisions were more common in the younger cohort (89, 44.7%), and they were associated with more C5-C7 fractures (47, 23.6%; 60, 30.2%; and 66, 33.2%, respectively) including the facets (49, 24.6%), spinous processes (31, 15.6%), and transverse processes (52, 26.1%). Overall, the rates of instability, surgical intervention, and asymptomatic fractures were similar in the 2 age groups. Cervical spine fractures appear in about 1.8% of the CT scans performed in a busy emergency department environment. Fractures in the elderly occur more commonly due to falls, are located at C1 and C2, and may involve ligamentous injuries. Younger patients incur trauma more commonly due to motor vehicle collisions, and they are more likely to affect the posterior elements, especially C5-C7. The differences in trends for fractures in the 65 years of age and older and younger than 65 years of age groups have persisted since the Canadian C-Spine Rule 1996-1998 data were collected.

Anatomic variation of the vertebral artery: a case involving a persistent first intersegmental artery at C1-C2.

We observed a rare anatomical variation of a persistent first intersegmental vertebral artery in the C1-C2 region in an elderly Chinese male cadaver at Changzhi Medical College. In this case, the vertebral artery, rather than passing through the transverse foramen of the atlas, exits the transverse foramen of C2 and enters the spinal canal at the lower portion of the C1 posterior arch. The original transverse foramen of C1 was filled with connective tissue. This report details the anatomical characteristics of this abnormal vertebral artery and discusses its anatomical, surgical, and developmental implications. We describe the detailed morphological features of a rare VA variant and discuss the anatomical, clinical, and developmental aspects of this case. A case of head dissection. The anatomical characteristics of the VA were studied and documented, and anatomical measurements were collected. In this case, the vertebral artery, rather than passing through the transverse foramen of the atlas, exits the transverse foramen of C2 and enters the spinal canal at the lower portion of the C1 posterior arch. The original transverse foramen of C1 was filled with connective tissue. The anomalous development of segmental arteries in our case is linked to failures in the embryonic sclerotome reconstruction during development and failure.

Prevalence of occipitalisation in a South African Black population: An original study of 1119 skulls with a review of the literature

BackgroundOccipitalisation is the most prevalent congenital abnormality at the craniovertebral junction; however, it is rare in the general population. There is a paucity of literature on osteological prevalence studies within the South African Black and broader African populations. This study aimed to establish baseline data for the prevalence of occipitalisation in the South African Black population group. MethodsOne thousand two hundred thirteen skulls from a South African Black population were initially sampled, and after exclusion criteria were applied, the sample was reduced to 1119 skulls (male 766; female 353). A morphological description of the skulls that exhibited occipitalisation was included in this study. ResultsOccipitalisation was observed in three skulls (3/1119; 0.27 %); two of the skulls were female (2/353; 0.57 %), and one was male (1/766; 0.13 %). The three occipitalised skulls exhibited fusion in three areas of the atlas: the anterior arch, lateral masses, and transverse processes. No skulls exhibited posterior arch fusion of the atlas. ConclusionThis study established a baseline prevalence of occipitalisation in the South African Black population at 0.27 % and found no significant association between sex and occipitalisation (p = 0.236). This study highlights the need for further studies in the other African population affinity groups.

Laryngeal chondrosarcoma, a 30-year series

Introduction and objectivesLaryngeal chondrosarcoma is a rare laryngeal pathology arising from cartilaginous structures and is predominantly found in the cricoid cartilage. This study investigates its presentation, treatment modalities and patient outcomes. Patients or materials and methodsRetrospective study of laryngeal chondrosarcoma cases followed from 1992 to 2022 in the Otorhinolaryngology department of a cancer center - Instituto Português de Oncologia de Lisboa. Statistical analysis was made with Microsoft Excel® and SPSS®. ResultsWe identified 16 cases, of which two-thirds were male, with an average age of 59.6 years, and only 24% of them had a history of smoking. The commonest presentation was indolent dysphonia and/or dyspnea, and the posterior arch of the cricoid cartilage was the most affected place. Although histopathological studies after biopsy were often inconclusive, surgery emerged as the first-line of treatment for all patients. Larynx microsurgery with lesion debulking was the most frequent surgical approach (47%) followed by partial laryngectomy (24%). Neither adjuvant radiotherapy (RT) nor chemotherapy was administered in any of the cases. There was residual tumor in 23% of the cases so half of these patients were in watchful waiting while the other part underwent further microsurgery or total laryngectomy. Only one patient with recurrence received RT. Disease-specific survival rate at 1 and 5 years was 97% and 91%, respectively. ConclusionLaryngeal chondrosarcoma etiology is still unknown and is effectively treated with surgery, with a generally favorable prognosis. The main concern lies in its propensity to relapse, highlighting the importance of watchful follow-up.

How successful is the CatBoost classifier in diagnosing different dental anomalies in patients via sella turcica and vertebral morphologic alteration?

BackgroundTo investigate how successfully the classification of patients with and without dental anomalies was achieved through four experiments involving different dental anomalies.MethodsLateral cephalometric radiographs (LCRs) from 526 individuals aged between 14 and 22 years were included. Four experiments involving different dental anomalies were created. Experiment 1 included the total dental anomaly group and control group (CG). Experiment 2 only had dental agenesis and a CG. Experiment 3 consisted of only palatally impacted canines and the CG. Experiment 4 comprised patients with various dental defects (transposition, hypodontia, agenesis-palatally affected canine, peg-shaped laterally, hyperdontia) and the CG. Twelve sella measurements and assessments of the ponticulus posticus and posterior arch deficiency were given as input. The target was to distinguish between anomalies and controls. The CatBoost algorithm was applied to classify patients with and without dental anomalies.ResultsIn order from lowest to highest, the predictive accuracies of the experiments were as follows: experiment 4 < experiment 2 < experiment 3 < experiment 1. The sella area (SA) (mm2) was the most important variable in experiment 1. The most significant variable in prediction model of experiment 2 was sella height posterior (SHP) (mm). Sella area (SA) (mm2) was again the most relevant variable in experiment 3. The most important variable in experiment 4 was sella height median (SHM) (mm).ConclusionsEvery prediction model from the four experiments prioritized different variables. These findings may suggest that related research should focus on specific traits from a diagnostic perspective.

How I do it: en-bloc thoracic vertebrectomy.

Some young patients with preserved functional status suffering from aggressive isolated neoplastic disease of the thoracic spine may be eligible from curative en-bloc vertebrectomy surgical treatment. Long-segment posterior pedicle screw fixation is performed. Complete excision of the posterior arch and of ribs posterior aspect is performed. Finger blunt dissection is performed between vertebral body, pleura, and aorta allowing to place a soft abdominal valve and then Gigli saws surrounding the anterior aspect of the spine, in order to saw the upper and the lower discs. Unilateral temporary rod is placed. The vertebral body is dislodged from posterior ligament and then removed by circling laterally around spinal cord. An expandable vertebral implant is placed. Posterior en-bloc thoracic vertebrectomy is a highly technical yet achievable procedure which carries a curative intent for isolated neoplastic spine lesions.

AIRWAY CHALLENGES IN A ANKYLOSING SPONDYLITIC PATIENT WITHTRAUMATIC CERVICAL SPINE FRACTURE - A CASE REPORT

Background:Ankylosing Spondylitis (AS) is a chronic inflammatory condition that results in the fusion of the spine and decreased flexibility, commonly known as bamboo spine. This condition presents significant challenges to anesthesiologists due to potential difficulties in managing the airway, cardiovascular issues, and compromised respiration. AS patients face an increased risk of fractures and spinal cord injury, especially in the cervical spine, which is prone to instability and higher morbidity and mortality rates. Maneuvers to manage the airway and intubation techniques may exacerbate movement in the cervical spine, potentially leading to further injury. Case Report: A 42-year-old man with a history of AS presented with a cervical spine injury after a road traffic accident. MRI showed fractures at the posterior arch of C1 and C4-C5 levels with nerve root compression. The patient, who was not regularly followed up, was taking medication. Preoperative assessment revealed a potentially difficult airway, and the patient had quadriparesis and reduced sensation. Due to the risk of spinal cord injury, an awake fiberoptic intubation (AFOI) was planned. The AFOI was successfully performed through the nasal route, and the patient underwent a C4-C5 discectomy and stabilization. The postoperative recovery was uneventful, with no new neurological deficits. Discussion: The case emphasizes the need to minimize movement of the cervical spine when managing the airway in AS patients with cervical spine fractures. Using AFOI is more effective than other techniques in this scenario, as it minimizes cervical movement and allows for post-intubation neurologic assessments. Although the glidescope video laryngoscope and intubating laryngeal mask airway are considered as alternatives to direct laryngoscopy, anesthesiologists still prefer AFOI as the primary option. Conclusion: This case report demonstrates the best airway management for an AS patient with a cervical spine fracture, with a focus on the role of the anesthesiologist in preventing further injury and neurologic deterioration. Awake fiberoptic intubation is the safest alternative for AS patients with cervical spine fractures, as long as the anesthesiologist has the requisite skills and knowledge.

Modified Atlantoaxial Arthrodesis Technique for Atlantoaxial Instability via Intraarticular Autografting Using Structural Iliac Bone: Technical Nuances and Case Series

ObjectiveThe present study described a modified technique of atlantoaxial arthrodesis in patients with atlantoaxial instability (AAI) along with the postoperative clinical and radiological results. MethodsFive patients underwent this method for their AAI concurrent with C1 arch hypoplasia and/or the development of odontoid pannus causing myelopathy. After thorough exposure of the posterior surface of the C1-2 complex, the bilateral C2 nerve roots were sectioned to allow for easier access to the C1/2 facet joints. To prepare a suitable grafting bed, the C1/2 facet capsule was opened, then the articular cartilaginous and synovial tissues were thoroughly removed. After being properly fashioned to match the gap between the C1/2 facet joint spaces, the structural bone grafts from the iliac crest were directly inserted into the facet joint spaces. To alleviate cord compression caused by concomitant odontoid pannus and/or hypoplastic C1 arch, C1 laminectomy was necessitated in all cases. Subsequently, posterior screw-rod instrumental fixation was conducted. ResultsAll five patients underwent this procedure successfully. Clinical and radiological follow-up data of all patients indicated favorable relief of clinical symptoms and early rigid C1-2 stability. The sequelae of C2 nerve resection were not remarkable. No other neural or vascular damage associated with this technique was observed. ConclusionModified atlantoaxial arthrodesis via intraarticular autografting using the structural iliac bone combined with posterior instrumentation appears to be an efficient alternative treatment method for AAI patients with concurrent pathologies, even when the C1-2 posterior arches are unavailable for the grafting bed.

Ponticulus posticus and skeletal malocclusion: A pilot study in a Southern Italian pre-orthodontic court.

Ponticulus posticus (PP) is a bony protrusion located between the posterior portion of the superior articular process and the posterolateral portion of a posterior arch of the atlas vertebrae in the cervical spine. The aim of this study is to verify the presence of different types of PP in a Southern Italian pre-orthodontic cohort to understand its correlation with skeletal class and maturity. A case-control retrospective study was conducted, utilizing 212 latero-lateral telecranium radiographs to analyze skeletal maturity according to the cervical vertebral maturation method, the Angle's classification of malocclusion (I, II, or III), and the presence or absence of the PP, whether complete (c-PP) or partial (p-PP). A total of 212 lateral cephalograms were analyzed. Of the 72 male patients, 67 (93%) exhibited PP, and 116 (88%) were PP. The chi-square value was 0.001, while Cramer's V was 0.270, indicating a significant correlation between age groups and PP presence, and a very strong association overall. Out of the 41 complete PP cases, class I was notably more prevalent than classes II and III. Orthodontists should carefully consider PP when assessing and treating individuals with or without skeletal discrepancies and dental anomalies.

Maxillary arch dimensions in bilateral cleft lip and palate in the age 0-5 months.

The complete bilateral cleft lip and palate (BCLP) divides the maxillary arch into three segments, separated from each other, resulting in abnormal growth of the alveolar arch. This study evaluated the maxillary arch dimensions in BCLP and compared them with neonates without craniofacial anomalies. This retrospective study was conducted in a tertiary cleft centre. Sixty-six neonates aged 0-5 months were divided into two groups: cleft group-children with BCLP (23 boys and 18 girls) and control group-children without craniofacial deformities (15 boys and 10 girls). The dental models were processed by a 3D scanner. Landmarks were marked to achieve inter-canine distance, inter-tuberosity distance and arch length measurements. t-Tests were used for intergroup comparisons (p < .05). The maxillary cleft arch was demonstrated to be wider and longer in the posterior region compared to the control group. The inter-canine distance did not present differences between the cleft and controls. The inter-canine distance of the control group was the only measurement influenced by the variable sex. The cleft significantly interfered with the arch posterior width and arch sagittal length, making them larger. There was no statistical difference in the measurements between sex in the cleft group.

Pediatric atlas anatomy and its implications for fracture treatment: an anatomical and radiological study

Introduction and objectivesThe objective of the study was: (1) to describe changes in the shape of the atlas during growth, including gender and side differences; (2) to assess the dimension essential for identification of the optimal entry point; (3) to determine the age limit for a safe insertion of 3.5-mm screws into the lateral masses according to our own limiting parameters. Materials and methodsDimensions of the atlas were measured on 200 CT scans of the craniocervical junction in individuals aged 0–18 years and on 34 anatomical specimens of the first cervical vertebra (aged 2.5–18 years). Both series were divided according to the gender and age. The values measured on CT scans were used for statistical comparison of data in boys and girls and comparison of the right and left sides. ResultsThe atlas reaches its maximum growth rate between 0 and 2 years of age, then the growth decelerates and continues until the age of 18 years. The proportion of dimensions of C1 vertebral foramens changes with age. The youngest children show a relatively greater distance from the left to the right medial pedicle; around the age of 5 the values get even and subsequently the distance from the inner wall of anterior to posterior arch gets relatively greater. The transverse foramen has a slightly oval shape throughout the period of growth. Statistically significant differences between boys and girls were observed primarily between 12 and 18 years of age. ConclusionThe study has proved adequate size of lateral masses for insertion of 3.5-mm screws in all patients from the age of 5 years. In younger children, the patient´s anatomy should be respected and the surgical technique tailored accordingly.

Comparison of Transoral Anterior Jefferson-Fracture Reduction Plate and Posterior Screw-Rod Fixation in C1-Ring Osteosynthesis for Unstable Atlas Fractures.

To compare the clinical outcomes of transoral anterior Jefferson-fracture reduction plate (JeRP) and posterior screw rod (PSR) surgery for unstable atlas fractures via C1-ring osteosynthesis. From June 2009 to June 2022, 49 consecutive patients with unstable atlas fractures were treated by transoral anterior JeRP fixation (JeRP group) or PSR fixation (PSR group) and followed up at General Hospital of Southern Theatre Command of PLA; 30 males and 19 females were included. The visual analogue scale (VAS) score, Neck Disability Index (NDI), distance to anterior arch fracture (DAAF), distance to posterior arch fracture (DPAF), lateral mass displacement (LMD), Redlund-Johnell value, postoperative complications, and fracture healing rate were retrospectively collected and statistically analyzed. Compared with that in the PSR group, the bleeding volume in the JeRP group was lower, and the length of hospital stay was longer. The VAS scores and NDIs of both groups were significantly improved after surgery. The postoperative DAAF and DPAF were significantly smaller after surgery in both groups. Compared with the significantly shorter DPAF in the PSR group, the JeRP group had a smaller DAAF, shorter LMDs and larger Redlund-Johnell value postoperatively and at the final follow-up. The fracture healing rate at 3 months after surgery was significantly greater in the JeRP group (p < 0.05). Both C1-ring osteosynthesis procedures for treating unstable atlas fractures yield satisfactory clinical outcomes. Transoral anterior JeRP fixation is more effective than PSR fixation for holistic fracture reduction and short-term fracture healing, but the hospital stay is longer.

Strategies and safety simulations for ultrasonic cervical spinal cord neuromodulation

Objective. Focused ultrasound spinal cord neuromodulation has been demonstrated in small animals. However, most of the tested neuromodulatory exposures are similar in intensity and exposure duration to the reported small animal threshold for possible spinal cord damage. All efforts must be made to minimize the risk and assure the safety of potential human studies, while maximizing potential treatment efficacy. This requires an understanding of ultrasound propagation and heat deposition within the human spine. Approach. Combined acoustic and thermal modelling was used to assess the pressure and heat distributions produced by a 500 kHz source focused to the C5/C6 level via two approaches (a) the posterior acoustic window between vertebral posterior arches, and (b) the lateral intervertebral foramen from which the C6 spinal nerve exits. Pulse trains of fifty 0.1 s pulses (pulse repetition frequency: 0.33 Hz, free-field spatial peak pulse-averaged intensity: 10 W cm−2) were simulated for four subjects and for ±10 mm translational and ±10∘ rotational source positioning errors. Main results. Target pressures ranged between 20%–70% of free-field spatial peak pressures with the posterior approach, and 20%–100% with the lateral approach. When the posterior source was optimally positioned, peak spine heating values were below 1 ∘C, but source mispositioning resulted in bone heating up to 4 ∘C. Heating with the lateral approach did not exceed 2 ∘C within the mispositioning range. There were substantial inter-subject differences in target pressures and peak heating values. Target pressure varied three to four-fold between subjects, depending on approach, while peak heating varied approximately two-fold between subjects. This results in a nearly ten-fold range between subjects in the target pressure achieved per degree of maximum heating. Significance. This study highlights the utility of trans-spine ultrasound simulation software and need for precise source-anatomy positioning to assure the subject-specific safety and efficacy of focused ultrasound spinal cord therapies.

Absence of the Posterior Element of C1 and C2 Along With Mild Wedge Shape in Body of C3: Case Report

Due to the wide variety of cervical vertebral congenital anomalies, knowledge of their types and related clinical conditions can prove to be helpful for physicians and surgeons in the diagnosis and treatment of patients. The aim of this study is to report on a rare case of unstable cervical vertebral congenital anomaly in which the patient had a defect in the body of the C3 vertebra in addition to defects in the posterior arch of C1 and posterior element of C2. This type of anomaly has not been reported so far in the literature. To reduce the patient’s related neurological disorders, our treatment choice for this patient was occipitocervical fusion (OCF) surgery. At the 3-year postoperative follow-up, all sensory and motor problems related to this anomaly affecting the patient's upper and lower limbs and causing shoulder and neck pain were eliminated. In this rare type of anomaly, OCF surgery seems to be an effective choice in relieving the patient's neurological symptoms.