Identifying and exploring the favorable factors that help to slow the progression of disease in patients with mild cervical spondylotic myelopathy.

To explore the favorable factors that help slow the progression of disease in patients with mild Cervical Spondylotic Myelopathy (CSM). A retrospective analysis was conducted, involving the enrollment of 115 CSM patients. The categorization of patients into two groups was based on the duration of symptoms, assessments using the mJOA scale and Health Transition (HT) scores: mild-slow group and severe-rapid group. We found that the patients in both groups had similar degrees of spinal cord compression, but mild-slow group were older and had smaller C2-C7 cobb angle (Flexion) (CL(F)), C2-C7 cobb angle (Range of motion) (CL(ROM)), Transverse area (TA), Normal-TA, Compressive spinal canal area (CSCA), Normal-Spinal canal area (Normal-SCA) and lower Spinal cord increased signal intensity (ISI) Grade than the severe-rapid group. A binary logistic regression analysis showed that CL(ROM) and Normal-TA are favorable factors to help slow the progression of disease patients with mild CSM. Through ROC curves, we found that when CL(ROM) < 39.1° and Normal-TA < 80.5mm2, the progression of disease in CSM patients may be slower. Meanwhile, we obtained a prediction formula by introducing joint prediction factor: L = CL(ROM) + 2.175 * Normal-TA. And found that when L < 213.0, the disease progression of patients may be slower which was superior to calculate CL(ROM) and Normal-TA separately.

Digital anatomical features of morphological development in C2-C7 neurocentral synchondrosis in children aged 1-6 years: a retrospective study of CT images.

BACKGROUND: With the continuous improvement of diagnosis and treatment technology for cervical spine-related diseases in children at home and abroad, the demand for exploring the developmental anatomy and function of children's cervical spine of different ages is increasing. So the aim of this study was to investigate the changes of anatomical indicators in neurocentral synchondrosis (NCS) of C2-C7 with age and the developmental characteristics of different vertebrae in children aged 1-6 years old. METHOD: A retrospective collection of 160 cases of normal cervical spine CT images of children aged 1-6 years old in provincial tertiary hospitals, according to the age group of 1-year-old into 6 groups. The original data of continuously scanned cervical spine tomography images were imported into Mimics16.0 software, under the two-dimensional image window, selected the measurement tool under the Measurements toolbar to measure and statistically analyzed the anatomical indicators such as cross diameter, sagittal diameter, height, perimeter and area of NCS in the C2-C7 segment of the cervical spine on the coronal plane and cross-section. RESULTS: There was no significant difference in the anatomical indexes of cervical spine NCS in children compared with the left and right sides of the same vertebrae (P > 0.05). The same cervical spine generally had differences between the age groups of 1-4 years old and 5-6 years old (P < 0.05).The transverse diameter and circumference gradually decreased with age; the sagittal diameter and height showed a slight increase trend; there was a maximum area at 2 years of age. In different cervical vertebrae of the same age group, the NCS values of C3, C4, and C5 varied greatly, which showed that the ossification process of cervical cartilage was faster than that at the upper and lower ends. There were obvious differences between C2 and the rest of the cervical vertebral segments' NCS ossification process. C7 was also very different from the rest of the cervical vertebrae segments, presumably more similar to the thoracic spine. CONCLUSIONS: The anatomical indexes of C2-C7 NCS in children have obvious developmental regularities at different ages, and there are also regularities between cervical segments.

Sex Determination via the Second Cervical Vertebra and Odontoid Process: A Case Report and a Review of the Literature.

Determining an individual's sex is crucial in several fields, such as forensic anthropology, archaeology, and medicine. Accurate sex estimation, alongside the estimation of age at death, stature, and ancestry, is of paramount importance for creating a biological profile. This profile helps narrow the potential pool of missing persons and aids identification. Our research focuses on the second cervical vertebra and odontoid process, which is particularly valuable due to their high sexual dimorphism. This brief research is structured as follows: we provide an overview of morphometric analysis of the second cervical vertebra for accurate sex estimation in forensic anthropology. We then delve into a case report to explore sexual dimorphism of the C2 vertebrae. Moreover, we discuss some of these studies that showed a significant correlation between the dimensions of the second cervical vertebrae and height, suggesting that the C2 can be used as a reliable indicator for stature estimation. The high accuracy rate of sex estimation using the second cervical vertebrae suggests that this method is a valuable tool for forensic anthropologists. Its practical application can significantly contribute to identifying and profiling individuals in a forensic context, thereby aiding in the identification process.

C1-C2 Transarticular Anterior Fixation for the Treatment of Atlantoaxial Traumatic Dislocation: A Clinical Case.

Fractures of the odontoid apophysis are one of the most frequent lesions in the elderly population, and an increasingly preponderant problem with the progressive aging of the world population. In the present work, we report a clinical case of an 88-year-old male patient who suffered a fall resulting in a type-II fracture of the odontoid apophysis on the Anderson-D'Alonzo classification. Given the age and comorbidities of the patient, we decided to perform osteosynthesis of the fracture through anterior fixation with a transarticular screw in combination with fixation with an odontoid screw. This technique enables the necessary stability for the consolidation of Anderson-D'Alonzo's type II odontoid apophysis fracture, with the advantage of the lower levels of dissection of the cervical extensor musculature and hemorrhage resulting from this aggression when compared with the posterior approach; moreover, it is a readily-available technique that yields clear benefits in the treatment of this pathology in the geriatric population.

Does ponticulus posticus affect vertebral artery diameter.

PURPOSE: Ponticulus Posticus, atlantooccipital ligament ossification-induced anomaly, surrounds the vertebral artery and the first cervical nerve root. It is believed to wrap around the first cervical nerve root and the vertebral artery, causing compression. We hypothesized that it would also reduce the diameter of the vertebral artery. METHODS: Between January 1, 2022, and December 31, 2022, cervical spine CT scans taken for any reason were retrospectively reviewed. The images of 1365 patients suitable for evaluation were evaluated by two expert radiologists in 3 dimensions. Among patients with PP, those who underwent cervical angiography were identified for vertebral artery diameter measurement. RESULTS: The average age of the 1365 individuals included in the study (732 males, 633 females) was 55.78 (± 18.85) with an age range of 1-96. Among this group, PP was detected in 288 individuals, resulting in a total prevalence of 21.1%. Right and left vertebral artery diameters were significantly lower in patients with complete PP compared to the absent group (p < 0,001, p < 0,001, respectively). Additionally, it was observed that width and height diameters and artery diameters were positively correlated in patients with Complete PP. CONCLUSIONS: Ponticulus posticus can cause vertebrobasilar insufficiency by reducing the diameter of the vertebral artery. Therefore, imaging and detailed evaluation of this region are important in symptomatic patients.

Analysis of surgical treatment of cervical spondylotic amyotrophy.

Background: Cervical spondylotic amyotrophy (CSA) is a special type of cervical spondylosis based on cervical degeneration, which is mainly manifested by weakness and atrophy of upper limb muscles without obvious sensory impairment. Various diagnostic and treatment strategies used; however, discrepancies exist. We tried to discuss diagnosing and treating CSA. Methods: 15 patients with CSA were diagnosed in the Orthopedics Department of the First Affiliated Hospital of Zhengzhou University, aged 42-70 years old. The duration of preoperative symptoms of amyotrophy was 6 to 240 months. 12 patients received surgical treatment, and 3 patients received conservative treatment. The patients were divided into two groups according to the site of preoperative amyotrophy. The manual muscle test was used to evaluate the patients' muscle strength pre-and postoperatively. Results: During postoperative follow-up, the muscle strength of 12 patients improved to different degrees compared to before surgery. The improvement effect was excellent in 2 cases, good in 6, and moderate in 4. There was no decrease in postoperative muscle strength compared with that before surgery. The satisfaction rate of the effect was 66.7%. The two groups had no statistically significant difference in preoperative muscle strength. The postoperative muscle strength of the proximal group was significantly better than that of the distal group. Conclusion: The surgical effect of CSA of the proximal type is significantly better than that of the distal type. The recovery effect of amyotrophy after surgery for distal type CSA is poor; thus, surgical treatment should be carefully considered.

Characterization and Association of the Missing Ventral Tubercle(s) from the Sixth Cervical Vertebra and Transpositions on the Ventral Surface of the Seventh Cervical Vertebra in Modern Equus ferus caballus.

In recent years, equine complex vertebral malformation (ECVM) has been of concern in the equine community, with studies identifying numerous associative morphological variations. Here, we examine the morphological association between C6 and C7 for dependency in ECVM cases, where the partially absent ventral process of C6 transposes on the ventral surface of C7. A C6 ventral process presents two tubercles, one cranial (CrVT) and one caudal (CVT). In this study, the C6 osseous specimens (n = 85) demonstrated a partial or completely absent CVT (aCVT) graded 1-4 that often extended cranially creating a partially absent cranial ventral tubercle (aCrVT) graded 1-3. In the 85 C6 osseous specimens examined, the corresponding C7s demonstrated either a complete or incomplete transposition of the ventral process from C6 in 44/85, with 30/44 replicating a transverse foramen. A strong statistical dependency existed between C6 grade 4 aCVTs and grades 1-3 aCrVTs and C7 transpositions with replicated transverse foramen. Sidedness was also demonstrated, where a left sided absent C6 associated with transposition on the left ventral surface of C7. This likewise applied to right sidedness and most bilateral cases. These findings might benefit practitioners when radiographing the extent of the ECVM configuration in patients presenting caudal cervical pain.

Transpedicular Contrast-enhanced CT-guided biopsy of the body and dens of the axis avoiding the trans-oral approach: Technical report and literature review.

This technical report illustrates the technique to perform computed tomography (CT)-guided bone biopsies in the body and dens of the axis (C2 vertebra) through a posterior transpedicular approach with the use of preoperative contrast-enhanced scans to highlight the course of the vertebral artery. The technique is presented through two exemplification cases: a pediatric patient with osteoblastoma and secondary aneurysmal bone cyst and one adult patient with melanoma metastasis. This case highlights the potential of the CT-guided posterolateral/transpedicular approach for performing safe and effective biopsies in the body and dens of C2, even in pediatric patients.

Case report: MRI and CT imaging features of a melanocytic tumour affecting a cervical vertebra in an adult dog, and review of differential diagnosis for T1W-hyperintense lesions.

A 7-year-old Lhasa Apso presented with a history of left thoracic limb lameness and neck pain. Magnetic resonance imaging revealed a well-defined, extradural lesion that was hyperintense on T1-weighted (T1W) images and isointense on T2-weighted (T2W) images and T2* images located at the left lamina of the C4 vertebra. Computed tomography showed an isoattenuating and contrast-enhancing mass centered on the left C4 vertebral lamina with associated osteolysis. The mass was surgically debulked, and histopathology revealed a malignant melanocytic tumour. The patient recovered completely and received radiotherapy and three doses of the melanoma vaccine as adjunctive treatment. Eighteen months following treatment, the patient presented with neck pain again, but further investigations were declined at this stage, and the patient was euthanised. To the author's knowledge, this is the first case report describing the imaging characteristics of a cervical extradural melanocytic tumour in a dog. This case illustrates the MRI and CT imaging features and treatment of a canine melanocytic tumour of the cervical vertebrae.

Comparison of the S8 navigation system and the TINAVI orthopaedic robot in the treatment of upper cervical instability.

The objective is to compare the clinical efficacy and safety of the S8 navigation system and the Tinavi orthopaedic surgery robot in the treatment of upper cervical instability. The research methods adopted are as follows. The clinical data of patients with upper cervical instability who underwent surgery from May 2021 to December 2021 were analysed retrospectively. Patients were divided into a navigation group (assisted by the S8 navigation system) and a tinavi group (assisted by the Tinavi robot) according to the auxiliary system used. Computed tomography and digital radiography were performed after the operation. The accuracy of pedicle screw placement was evaluated using the criteria put forward by Rampersaud. Degree of facet joint violation, visual analogue scale score, neck disability index and Japanese orthopaedic association score were recorded and assessed during follow-up examinations in both groups. Record two groups of surgery-related indicators. Record the complications of the two groups. A total of 50 patients were included. 21 patients in the navigation group and 29 in the tinavi group. The results of the study are as follows. The average follow-up time was 12.1 months. There was no significant difference in nail placement accuracy between the navigation and tinavi groups (P > 0.05); however, the navigation group had a significantly higher rate of facet joint violation than that of tinavi group (P < 0.05), and the screws were placed closer to the anterior cortex (P < 0.05). Significantly more intraoperative fluoroscopies were performed in the tinavi group than in the navigation group, and the operation time was significantly longer in the tinavi group than in the navigation group (P < 0.05). The time of single nail implantation, intraoperative blood loss and incision length in navigation group were significantly longer than those in tinavi group. There were no statistically significant differences in other indicators between the two groups (P > 0.05). We come to the following conclusion. The Stealth Station S8 navigation system (Medtronic, USA), which also uses an optical tracking system, and the Tinavi Orthopedic robot have shown the same high accuracy and satisfactory clinical results in the treatment of upper cervical instability. Although the S8 navigation system still has many limitations, it still has good application prospects and is a new tool for spine surgery.

[Feasibility of a novel type of complex anterior cervical fixation by using Mimics software].

OBJECTIVE: To investigate the feasibility of mimics software in analyzing a new type of complex anterior cervical fixation -- anterior transpedicular screw fixation+zero notch internal fixation. METHODS: From January 2021 to September 2022, 50 normal pedestrians who underwent cervical spine CT scanning were selected for C1-C7 segment scanning, including 27 males and 23 females, aged from 25 to 65 years old with an average of (46.0 ± 9.0) years old. The dicom format is exported and engraved into the CD, and use the mimics software to perform 3D reconstruction of each segment. A simulated screw is placed on the image according to the critical value of zero notch screw (head and tail angle 44°, internal angle 29°). The position of zero notch screw in each segment is observed to determine the feasibility of anterior transpedicular screw fixation plus zero notch internal fixation. RESULTS: For the upper zero notch screws the three-dimensional images of the cervical spine across all 50 subjects within the C3-C7 segments demonstrated safe position, with no instances of intersection with ATPS. For the lower zero notch screw, in C3-C4 and C4-C5, 4 out of 50 subjects are in the safe position in the three-dimensional images of cervical vertebrae, and 46 cases could achieve secure screw placement when the maximum caudal angle is(32.3±1.9) ° and (36.1±2.2) °, respectively. In C5-C6 and C6-C7 segments, no lower zero notch screws intersected with ATPS, and all screws are in safe positions. CONCLUSION: Lower cervical anterior pedicle screw fixation plus zero notch internal fixation can achieve successful nail placement through the selected entry point and position.

Cervical epidural hematoma masquerading as thrombosis of intracranial flow diverter in situ: A diagnostic and therapeutic conundrum.

Cervical epidural hematoma (EDH) is a rare but very serious cause of acute neurologic compression that needs early diagnosis and rapid intervention. Acute hemiparesis is an infrequent presentation of cervical EDH and often mimics cerebrovascular accident. In this case, we describe the management of a case of cervical EDH presenting as acute hemiparesis in an elderly female patient which mimicked as thrombosis of intracranial flow diverter in situ. The report emphasizes that cervical EDH should be considered as differential diagnosis in patients who present with acute hemiparesis especially, who are on antiplatelets or anticoagulants. Also, in a patient considered high-risk for surgery, conservative management can be considered under close supervision and intensive monitoring, especially, in non-expanding hematoma and non-progressive neurological deterioration.

Current Concepts in the Treatment of Traumatic C2 Vertebral Fracture : A Literature Review.

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.

Computed Tomography-Based Morphometric Analysis of Lower Cervical Anterior Transpedicular Screw Fixation and Related Factors in the Chinese Population.

BACKGROUND: Anterior transpedicular screw (ATPS) internal fixation of the lower cervical spine is an alternative for patients who cannot tolerate combined anterior and posterior surgery. The cervical vertebral anatomy varies with many factors, including age, gender, height, weight, and race. METHODS: Three-dimensional (3D) CT reconstructions were performed on 122 patients. We selected the best level and measured the relevant parameters on both sides of the cervical vertebrae. RESULTS: We identified the entry point and orientation parameters of ATPS fixation for the C3-C7 vertebrae, and analyzed cervical pedicle parameters. Outer pedicle width (OPW), outer pedicle height (OPH), and pedicle axis length (PAL) were not correlated with body weight and age, but were positively correlated with body height (P < 0.05). After multiple linear regression analysis to exclude the effects of body height, no significant differences in OPW, OPH, and PAL were found between male and female subjects at most cervical levels. Pedicle cortical thickness was negatively correlated with age (P < 0.05). The percentage of pedicles with OPW <4.5 mm was: C3, 38.10%; C4, 34.92%; C5, 12.70%; C6, 9.52%; and C7, 0%. The percentage of pedicles with OPWs ≤4.5 mm, ≤4.0 mm, and ≤3.5 mm was higher among subjects with body height <160 cm. CONCLUSIONS: This study presents the internal anatomy of the cervical spine and provides accurate preoperative evaluation data for ATPS fixation. OPW, OPH, and PAL are positively correlated with body height, while pedicle cortical thickness is negatively correlated with age.

Analysis on clinical efficacy of anterior cervical Hybrid surgery and posterior cervical expansive open-door laminopasty for multilevel cervical spondylotic myelopathy / 吉林大学学报(医学版)

Objective:To analyze the efficacy of anterior cervical Hybrid surgery and posterior cervical expansive open-door laminoplasty(EODL)in the treatment of multilevel cervical spondylotic myelopathy,and to discuss the selection of surgical methods for the patients with multilevel cervical spondylotic myelopathy.Methods:The retrospective analysis was conducted of 70 patients with multilevel cervical spondylotic myelopathy who underwent surgery at Affilated Beijing Traditional Chinese Medicine Hospital of Capital Medical University from July 2017 to July 2020.Based on the different surgical methods,the patients were divided into anterior group(n=35)and posterior group(n=35).The patients in anterior group underwent Hybrid surgery[anterior cervical discectomy and fusion(ACDF)combined with artificial cervical disc replacement(ACDR)],and the patients in posterior group underwent EODL.The hospitalization time,operation time,intraoperative blood loss,and postoperative drainage volume of the patients in two groups were recorded;the efficacy was evaluated by Japanese orthopaedic association(JOA)score,JOA improvement rate,neck disability index(NDI),visual analogue scale(VAS)for pain,and postoperative satisfaction score;the complications of the patients in two groups after surgery were recorded.Results:Compared with posterior group,the intraoperative blood loss,postoperative drainage volume,hospitalization time,and operation time of the patients in anterior group were significantly decreased(P<0.01),and the preoperative score had no significant difference(P>0.05).At the final follow-up after surgery,compared with posterior group,the JOA score and JOA improvement rate of the patients in anterior group were significantly increased(P<0.01),and the NDI score and VAS score were significantly decreased(P<0.01).Compared with before surgery,the JOA scores of the patients in two groups at the final follow-up after surgery were increased(P<0.01),and the NDI and VAS scores were significant decreased(P<0.01).The postoperative satisfaction of the patients in two groups was high based on the postoperative satisfaction score.There was no significant difference in the incidence of postoperative complication of the patients between two groups(P>0.05).Conclusion:Both the anterior cervical Hybrid surgery and EODL achieve the satisfactory results in the treatment of multilevel cervical spondylotic myelopathy.Hybrid surgery has the advantages of less bleeding and shorter surgery time,and the most suitable surgical method should be chosen clinically based on the actual situation of the patients.

Finite element analysis of the correlation between tilt angle of titanium cage and postoperative subsidence of titanium cage after anterior subtotal cervical corpectomy,decompression and fusion / 中国组织工程研究

BACKGROUND:Anterior subtotal corpectomy,decompression and fusion is a conventional method to treat cervical degenerative diseases.A titanium cage is an important implant to maintain the stability of the cervical spine after subtotal corpectomy.In recent years,many patients have complications such as titanium cage sinking,which are highly controversial. OBJECTIVE:To investigate the internal biomechanical relationship between the tilt angle of the titanium cage and postoperative titanium cage subsidence after anterior subtotal cervical corpectomy,decompression and fusion. METHODS:A three-dimensional finite element model of the C4-C6 segment was established by CT images of a normal human cervical spine,in which the anterior subtotal resection,decompression and fusion of the C5 vertebral body were simulated,and titanium cages with different tilt angles(-6° to-1° negative angle,that is,the front edge of titanium cage is shorter than the rear edge of titanium cage;1° to 6° positive angle,that is,the front edge of titanium cage is longer than the rear edge of titanium cage)were placed.After setting the boundary conditions,preloads of 50,100 and 150 N were applied respectively on the C4 vertebral body.The stress value of each contact point between the titanium cage and C4 lower-end plate and C6 lower-end plate(seven stress contact points on the contact surface of titanium mesh)was recorded and statistical analysis was conducted. RESULTS AND CONCLUSION:(1)The tilt angles of the titanium cage of the positive angle group and negative angle group under 50,100 and 150 N stress respectively were found by Mann Whitn test,with P<0.05,which was statistically significant.The dispersion coefficients of the positive angle group were smaller than those of the negative angle group under 50,100 and 150 N stress conditions.(2)Under 50,100 and 150 N stress conditions,the Wilcoxon sign rank test in the positive angle group of titanium cage tilt angle found that when the angle was set to 1° to 5°,the difference was not statistically significant(P>0.05).However,when the tilt angle of the titanium cage was set to 6°,the difference was statistically significant(P<0.05).(3)Under 50,100 and 150 N stress conditions,the Wilcoxon sign rank test in the negative angle group of titanium cage tilt angle found that when the tilt angle was set to-1° to-6°,the difference was not statistically significant(P>0.05).(4)It is concluded that in the sagittal position,the titanium cage with a positive tilt angle is more stable than with a negative tilt angle,which is more suitable for clinical use.The tilt angle of the titanium cage is relatively stable in the range of 1° to 5°.When the tilt angle is 6°,the stability starts to decline,which is easy to cause complications of titanium cage sinking after surgery.It is more suitable to select the titanium cage with a tilt angle of 1° to 5° according to the clinical situation during surgery to improve the efficacy.

Three-dimensional finite element analysis of a new horizontal screw-screw crosslink in posterior atlantoaxial internal fixation / 中国组织工程研究

BACKGROUND:The addition of traditional rod-rod fixation for atlantoaxial joint disease to C1-C2 pedicle screw-rod fixation(C1-C2 PSR)can provide stronger anti-rotation stability for screw/rod fixation,but there is a risk of installation difficulties,impact on bone graft bed,and spinal cord injury.The new horizontal screw-screw crosslink(hS-S CL)designed by the authors can effectively overcome the above shortcomings,but its biomechanical properties are unclear. OBJECTIVE:To analyze biomechanical properties of new horizontal screw-screw crosslink in C1-C2 PSR by three-dimensional finite element analysis. METHODS:CT thin layer scanning data were collected from the occipital base to the axis(C0-2)of one adult healthy male volunteer.The atlantoaxial finite element models were established respectively:the normal group,the unstable group,the non-crosslink group(unstable+C1-C2 PSR),and the crosslink group(C1-C2 PSR+hS-S CL).Range of motion and Von Miss Stresses in flexion and extension,lateral flexion and rotation of the four groups were calculated by applying 1.5 Nm torque to each finite element model,and the stress cloud was extracted. RESULTS AND CONCLUSION:(1)Range of motion of the unstable group was increased by 43.8%-78.7%compared with the normal group,and the range of motion of the internal fixation groups was 90.2%-98.7%lower than that of the unstable group under six conditions.The range of motion of the crosslink group and the non-crosslink group was basically the same in flexion and extension states,but in lateral flexion and rotation states,the range of motion of the crosslink group decreased 34.3%-43.8%and 78.6%-79.1%,respectively,compared with the non-crosslink group,and range of motion decreased most obviously in rotation state.(2)The stress peak of the internal plant model:The maximum stress of the crosslink group was generally smaller than that of the non-crosslink group,and the stress peak value of all the internal fixation groups was the lowest when the extension was carried out.(3)The stress cloud of internal plants showed that there was no obvious stress concentration phenomenon in the internal fixation,and the main stress distribution areas were the screw root and bone joint,and the crosslink ends were the screw tail groove or the joint rod joint.(4)The new horizontal screw-screw crosslink can obviously improve the anti-rotation stability of internal fixation and it can share part of the pressure in the three-dimensional motion direction of the internal fixation system and reduce the maximum stress of the internal plants.However,the stress distribution is obvious at both ends of the crosslink,and this part may be prone to fracture of the crosslink.

Micromorphological characteristics of the pedicle of the lower cervical vertebra / 中国组织工程研究

BACKGROUND:The lower cervical vertebral pedicle is the main stress site of the posterior column of the spine,which is of great significance for the maintenance of the stability of the human center of gravity and the reduction of shock.At present,there are few reports on the characteristics of the internal bone trabeculae,and the characteristics of the joint site of the vertebral pedicle with the articular process and the vertebral body.It is urgent to understand the fine anatomical structure of the vertebral pedicle and the relationship and function of each part. OBJECTIVE:To observe the microanatomical morphology of the vertebral pedicle by Micro-CT scanning of cervical vertebra specimens,and to measure and analyze the microstructure and morphometric parameters of the bone trabecula in the cervical pedicle under normal conditions to evaluate the safety performance of the cervical spine. METHODS:Micro-CT scanning was performed on 31 sets of cervical vertebrae C3-C7.By checking and reconstructing the areas of interest in the bone trabecular within the vertebral pedicle,the morphological characteristics and distribution direction of the bone trabecular within the cervical pedicle were observed,and the bone microstructure parameters were detected,and the differences in the bone microstructure of the C3-C7 vertebral pedicle were analyzed and compared. RESULTS AND CONCLUSION:(1)The Micro-CT images showed that the honeycomb bone trabeculae of the pedicle of the lower cervical spine presented a complex network of microstructures.The trabeculae near the cortical bone were lamellar and relatively compact,extending forward toward the vertebral body and backward toward the articular process lamina.Abatoid bone trabeculae extended into the medullary cavity and transformed into a network structure,and then into rod-shaped bone trabeculae.The rod-shaped bone trabeculae were sparsely distributed in the medullary cavity.(2)Statistical results of morphological parameters of bone trabeculae showed that bone volume fraction values in C4 and C5 were higher than that in C7(P＜0.05).The bone surface/bone volume value in C7 was higher than that in C3,C4 and C6(P＜0.05).The bone surface density of bone trabeculae in C7 was higher than that in C3,C4,C5 and C6(P＜0.05).Trabecular thickness in C7 was higher than that in C3,C4 and C5(P＜0.05).Bone surface/bone volume and bone surface density of the left pedicle bone trabecular were greater than those on the right side(P＜0.05).(3)The microstructural changes of C3-C7 were summarized,in which the load capacity and stress of the C7 pedicle were poor,and the risk of injury was high in this area.

Feasibility of a novel type of complex anterior cervical fixation by using Mimics software / 中国骨伤

OBJECTIVE@#To investigate the feasibility of mimics software in analyzing a new type of complex anterior cervical fixation -- anterior transpedicular screw fixation+zero notch internal fixation.@*METHODS@#From January 2021 to September 2022, 50 normal pedestrians who underwent cervical spine CT scanning were selected for C1-C7 segment scanning, including 27 males and 23 females, aged from 25 to 65 years old with an average of (46.0 ± 9.0) years old. The dicom format is exported and engraved into the CD, and use the mimics software to perform 3D reconstruction of each segment. A simulated screw is placed on the image according to the critical value of zero notch screw (head and tail angle 44°, internal angle 29°). The position of zero notch screw in each segment is observed to determine the feasibility of anterior transpedicular screw fixation plus zero notch internal fixation.@*RESULTS@#For the upper zero notch screws the three-dimensional images of the cervical spine across all 50 subjects within the C3-C7 segments demonstrated safe position, with no instances of intersection with ATPS. For the lower zero notch screw, in C3-C4 and C4-C5, 4 out of 50 subjects are in the safe position in the three-dimensional images of cervical vertebrae, and 46 cases could achieve secure screw placement when the maximum caudal angle is(32.3±1.9) ° and (36.1±2.2) °, respectively. In C5-C6 and C6-C7 segments, no lower zero notch screws intersected with ATPS, and all screws are in safe positions.@*CONCLUSION@#Lower cervical anterior pedicle screw fixation plus zero notch internal fixation can achieve successful nail placement through the selected entry point and position.