3D-CT reconstruction for pedicle outer width assessment in patients with thoracolumbar spine fractures: a comparative analysis between age groups <60 years and ≥60 years.

Objective: This study aims to compare the utilization of 3D-CT reconstruction in measuring pedicle outer width (POW) between younger/middle-aged patients (<60 years) and older patients (≥60 years) with thoracolumbar spine fractures (TSF). Methods: We conducted a retrospective study from January 2021 to December 2022, involving a total of 108 patients with TSF. The study population consisted of 62 patients aged ≥60 years (observation group) and 46 patients aged <60 years (control group). We compared the POW on both the right and left sides of the thoracolumbar spine between the two groups. Additionally, we analyzed the POW by gender within each group and calculated the incidence of patients falling below the critical values for arch root puncture (5 mm) and arch root nailing (7 mm) in both groups. Results: There were no statistically significant differences observed in the POW between the two groups on both the left and right sides of each corresponding vertebra (P > 0.05). In the observation group, both male and female patients had significantly smaller POW compared to the control group (P < 0.05). However, no significant difference in POW was observed between the same-sex groups in the L4 to L5 vertebrae (P > 0.05). In the observation group, the POW was less than 5 mm in 9.33% (81/868) of cases and less than 7 mm in 49.88% (433/868) of cases, primarily observed from T11 to L3. In the control group, 4.81% (31/644) of cases had a POW of less than 5 mm, and 13.81% (88/644) had a POW of less than 7 mm. Conclusion: Utilizing preoperative 3D-CT reconstruction to measure POW in patients with TSF not only facilitates the assessment of surgical feasibility but also aids in surgical pathway planning, thus potentially reducing the incidence of postoperative complications.

Correlation of Hounsfield Units with Bone Mineral Density and T-Score in Chinese Adults.

OBJECTIVE: To examine the association between vertebral cancellous Hounsfield units (HUs), age, bone mineral density, and T-score in a sample of Chinese adults. METHODS: The study included a sample of 739 participants. Age, bone mineral density, and T-score of each participant were recorded, and HUs were measured in the L1-L4 vertebrae. RESULTS: Data analysis revealed that HUs of vertebral cancellous bone across the pedicle level decreased with age, with women having higher values than men up to age 50 and vice versa thereafter. Furthermore, a positive correlation was found between HUs of vertebral cancellous bone across the pedicle level and bone mineral density/T-score in the L1-L4 vertebrae, but with a weaker correlation in the L4 vertebrae. Additionally, HU values for participants with osteoporosis were significantly lower than HU values for participants with osteopenia and normal bone health. CONCLUSIONS: From the findings of this study, it can be concluded that HUs may be a potential predictor of bone health, with implications for presurgical assessment of the quality of bone-screw interfaces for spinal surgery.

A Novel Free-hand Technique of Pedicle Screw Placement in the Lumbar Spine: Accuracy Evaluation and Preliminary Clinical Results.

OBJECTIVE: Pedicle screw implantation is the most common technique to achieve stability during spinal surgeries. Current methods for locating the entry point do not have a quantified criteria and highly rely on the surgeons' experience. Therefore, we aim to propose a quantified pedicle screw placement technique in the lumbar spine and to investigate its accuracy and safety in clinical practice. METHODS: We conducted a retrospective study involving 110 patients who received spinal surgery in our hospital from August 2018 to August 2021. All patients included had herniation of a single lumbar disc and were consistently treated with posterior discectomy, inter-body fusion, and transpedicular internal fixation. For 54 patients in the observation group, the pedicle screws were placed with our technique, which is located at 4 mm below the superior edge of the transverse process in line with the lateral margin of the superior articular process. For 56 patients in the control group, pedicle screws were placed according to the traditional crista lambdoidalis method. Comparisons were made in terms of the operation time, blood loss, time for exposure, the accuracy of placement, and postoperative complications. Furthermore, we applied our method to 64 patients with indistinguishable crista lambdoidalis and evaluated the accuracy of screw placement and clinical outcomes according to the visual analogue scale (VAS) and the Japanese Orthopaedic Association (JOA) score. RESULTS: There was no significant difference in intraoperative bleeding, accuracy of placement, and postoperative complications between our technique and the traditional crista lambdoidalis method (P > 0.05). However, the exposure time before screw placement (12.8 ± 0.3 vs. 17.4 ± 0.3, P = 0.001) and the total surgery time (97.2 ± 1.9 vs 102.3 ± 0.9, P = 0.020) were significantly shortened with our method. Additionally, in cases with indistinguishable crista lambdoidalis, our technique showed satisfying accuracy, with 97.6% screws placed in appropriate trajectory on the first attempt and all screws eventually positioned in the safe zone according to the Gertzbein-Robbins grading. All patients experienced steady improvement after surgery. CONCLUSION: Placing pedicle screws at 4 mm below the superior edge of the transverse process in line with the lateral margin of the superior articular process is a viable pedicle screw placement method. With this method, we observed a higher success rate and shorter operation time. In addition, this method can be applied in cases with indistinguishable crista lambdoidalis, and have satisfied success rate and clinical outcome.

Computed tomography measurement of the bone matrix of vertebral pedicle and its clinical significance.

BACKGROUND: To provide the anatomic basis for the clinical application of the transpedicular screw fixation. MATERIALS AND METHODS: Thirty spine (C2-L5) specimens were used. The width of the pedicle cortex and width of the pedicle medullary cavity (WPC and WPMC), and the height of the pedicle cortex and height of the pedicle medullary cavity (HPC and HPMC) were measured at the isthmus of the pedicle using computed tomography (CT) scanning. RESULTS: Width of the pedicle medullary cavity changed in a three-dovetailed-saddle shape with four peaks and three valleys, namely C2 (high), C4`5 (low), T2 (high), T4 (the lowest), T12 (high), L1 (low) and L5 (the highest). HPMC of the cervical pedicle changed in a saddle shape, gradually increasing from C5-L5. WPC, WPMC, HPC and HPMC showed a regular change, respectively. In each segment, the superior border of the pedicle cortex had a nearly consistent thickness to the interior border within an identical pedicle, while the pedicle cortex thickness radio of the medial and lateral border was nearly 3:1 among the cervical pedicles, 2:1 among thoracic pedicles, and 1:1 among lumbar pedicles. CONCLUSIONS: Both HPMC and WPMC are the dominant factors for the choice of screw diameter, but HPMC should also be considered in C2-T1 pedicles, especially C6 and C7. Additionally, the screw for C3-6 or T4-6 pedicles should be about 3.0 mm in diameter.

The Prevalence and Distribution of Vertebral Pedicles in Adolescent Idiopathic Scoliosis in Chinese people: A Computed Tomography-Based Study of 2958 Vertebral Pedicles.

OBJECTIVE: To explore the prevalence and distribution of abnormal vertebral pedicles in adolescent idiopathic scoliosis (AIS) in Chinese people. METHODS: We retrospectively reviewed AIS patients at a single institution between 2011 and 2017. Transverse pedicle widths from T1 to L5 were measured carefully using computed tomography, including cancellous and cortical channels. Pedicle morphology was classified as: type A, a cancellous channel larger than 4 mm; type B, a cancellous channel measuring 2-4 mm; type C, a cancellous channel smaller than 2 mm with an entirely cortical channel of 2 mm or greater; or type D, a cortical channel smaller than 2 mm. Types B, C, and D were defined as abnormal. Prevalence and distribution of abnormal pedicles were assessed. RESULTS: Eighty-seven patients with AIS, with a total of 2958 vertebral pedicles, were carefully measured and classified. The total prevalence of abnormal vertebral pedicles was as high as 65%, with type B comprising 40%, type C comprising 23%, and type D comprising 2%. Pedicles were located between T2 and T10 in 84% of type C and 91% of type D cases. Female sex, proximal thoracic location, major curve greater than 70 degrees, and concave pedicle may be risk factors for type C and D pedicles. CONCLUSIONS: There is a significantly high prevalence of abnormal pedicles in AIS in Chinese people, with a total prevalence of 65%. Female sex, proximal thoracic location, major curve greater than 70 degrees, and concave pedicle may be risk factors for type C and D pedicles.

A review of screw implantation accuracy in thoracolumbar vertebral pedicle / 临床外科杂志

Pedicle screw fixation is widely applied to spinal surgery owing to its advantages of maitaining the stability of spine,promoting the bone graft fusing and so on. Remarkably implantation accu-racy is not only closely related to ultimate fixation,but also can affect the incidence and the severity of complications. Consequently,to improve screw implantation accuracy is one of the goals that spinal sur-geons always pursue. In recent years,newly-developed techniques have been preliminarily used in clinic. An overview on the progresses of these techniques in China and overseas is presented here.

Accuracy and safety of pedicle screw placement for spinal deformity under intraoperative CT-assisted / 局解手术学杂志

Objective To evaluate the accuracy and safety of pedicle screw placement for spinal deformity under intraoperative CT-as-sisted.Methods The clinical data of 28 patients with spinal deformity,who underwent intraoperative CT-assisted placement of pedicle screws in our hospital from March 2014 to March 2017,were analyzed retrospectively.Intraoperative CT-assisted placement of pedicle screws was to observe the position of pedicle screws and adjust the screw position.The safety of pedicle screw fixation was assessed by the postoperative complications.Results All 28 patients of scoliosis were successfully performed surgery.A total of 402 pedicle screws were placed in the spines and the placements of 64 screws of them were adjusted according to intraoperative CT findings.Of 402 screws,377 were placed in the pedicles,13 by grade 1 pedicle breach,8 by grade 2 pedicle breach and 4 by grade 3 pedicle breach according to Gertzbein-Robbins classifi-cation of pedicle screw placement accuracy.No complication was directly related to the screws placement.No patient required reoperation due to the misplacement of the pedicle screws.Conclusion Intraoperative cone-beam CT scan can help the surgeon improve the accuracy and safety of pedicle screw placement for spinal deformity with less complication.

A Computed Tomography-Based Comparison of Abnormal Vertebrae Pedicles Between Dystrophic and Nondystrophic Scoliosis in Neurofibromatosis Type 1.

OBJECTIVE: To explore the prevalence and distribution of abnormal vertebral pedicles in scoliosis secondary to neurofibromatosis type 1 (NF1-S) and to compare the abnormal vertebrae pedicles between dystrophic and nondystrophic scoliosis. METHODS: Using computed tomography images, we carefully measured 2652 vertebral pedicles from 56 patients with NF1-S with dystrophic scoliosis and 22 patients with NF1-S with nondystrophic scoliosis. Pedicle morphology was classified as follows: type A, a cancellous channel of >4 mm; type B, a cancellous channel of 2 to 4 mm; type C, a cancellous channel of <2 mm with an entirely cortical channel of ≥2 mm; type D, a cortical channel of <2 mm; or type E, absent pedicle. Types B, C, D, and E were defined as abnormal. RESULTS: The total prevalence of abnormal vertebral pedicles in patients with NF1-S was as high as 67%, with type B comprising 39%, type C comprising 22%, type D comprising 4%, and type E comprising 2%. A significantly greater rate of abnormal pedicles was found in dystrophic scoliosis compared with nondystrophic scoliosis (70% vs. 59%, P < 0.0001). The upper thoracic spine (87%) is the most concentrated region of abnormal pedicles compared with the lower thoracic (73%) and lumbar spine (34%). CONCLUSIONS: There is a significantly high prevalence of abnormal pedicles in patients with NF1-S and an increased rate of abnormal pedicles in dystrophic scoliosis compared with nondystrophic ones. The described pedicle classification system could serve as an objective tool to guide preoperative assessment.

[Comparative study on treatment of thoracolumbar burst fractures with bone grafting by transpedicular approach and by interlaminal small fenestration].

Objective: To investigate the effectiveness and long-term stability of small fenestration vertebral bone grafting and transpedicular bone grafting in the treatment of Denis types A and B thoracolumbar burst fractures. Methods: Between January 2012 and February 2014, 50 patients with Denis type A or B thoracolumbar burst fractures were treated with vertebroplasty and pedicle screw rod fixation system, and the clinical data were retrospectively analyzed. Small fenestration vertebral bone grafting by trans-interlaminar approach was used in 30 cases (group A), and bone grafting by unilateral transpedicular approach was used in 20 cases (group B). X-ray and CT examinations of the thoracolumbar vertebrae were performed routinely before and after operation. There was no significant difference in sex, age, cause of injury, time from injury to operation, fracture type, injury segment, and preoperative Frankel classification, the percentage of the anterior body height of the injured vertebra, and visual analogue scale (VAS) score between two groups ( P>0.05). There was significant difference in preoperative Cobb angle of kyphosis between two groups ( P<0.05). The Cobb angle of kyphosis, the percentage of the anterior body height of the injured vertebra, and the recovery of neurological function were recorded and compared between two groups. Results: The patients were followed up for 16-31 months (mean, 19.1 months) in group A and for 17-25 months (mean, 20.2 months) in group B. Primary healing of incisions was obtained in the two groups; no nerve injury and other operative complications occurred. The neurological function was improved in varying degrees in the other patients with neurological impairment before operation except patients at grade A of Frankel classification. The lumbar back pain was relieved in two groups. There was significant difference in VAS score between before operation and at 3 months after operation or last follow-up in two groups ( P<0.05), but no significant difference was found between at 3 months and last follow-up in two groups and between two groups at each time point after operation ( P>0.05). X-ray examination showed that there was no breakage of nail and bar, or dislocation and loosening of internal fixation during follow-up period. The bone grafts filled well and fused in the fractured vertebra. The vertebral height recovered well after operation. The percentage of the anterior body height of the in-jured vertebra and Cobb angle of kyphosis at 1 week, 3 months, and last follow-up were significantly better than preope-rative ones in two groups ( P<0.05), but there was no significant difference between different time points after operation ( P>0.05), and between two groups at each time point after operation ( P>0.05). Conclusion: For Denis types A and B thoracolumbar burst fractures, vertebral bone grafting and pedicle screw internal fixation through interlaminal small fene-stration or transpedicular approach can restore the vertebral height, correct kyphosis, and maintain the vertebral stability, which reduce the risk of complications of loosening and breakage of internal fixators. The appropriate bone grafting approach can be chosen based on the degree of spinal canal space occupying, collapse of vertebral and spinal cord injury.

Research and development of cervical pedicle screw placement / 临床外科杂志

Since the instability of the spine caused by trauma,tumor,tuberculosis,deformity cor-rection and other reasons requires reconstruction,many scholars have conducted a large number of thorough researches,but the treatment options for unstable cervical spine still plague the clinicians.Considering the factors of stability and safety,more and more clinicians choose cervical pedicle screw placement as the treatment for spinal instability.In this work,the most common methods and the latest technologies of cervi-cal pedicle screw placement at home and abroad are summarized and reviewed.It provides references for clinical practices and presents the significance of high-tech assisted screw placement in the future.

Reconstruction of the hemipelvis with a modular prosthesis after resection of a primary malignant peri-acetabular tumour involving the sacroiliac joint.

We report our early experience with the use of a new prosthesis, the Modular Hemipelvic Prosthesis II, for reconstruction of the hemipelvis after resection of a primary malignant peri-acetabular tumour involving the sacroiliac joint. We retrospectively reviewed the outcome of 17 patients who had undergone resection of a pelvic tumour and reconstruction with this prosthesis between July 2002 and July 2010. One patient had a type I+II+III+IV resection (ilium + peri-acetabulum + pubis/ischium + sacrum) and 16 had a type I+II+IV resection (ilium + acetabulum + sacrum). The outcome was assessed at a mean follow-up of 33 months (15 to 59). One patient was alive with disease, 11 were alive without disease and five had died of disease. The overall five-year survival rate was 62.4%. Six patients had a local recurrence. The mean Musculoskeletal Tumour Society score was 58% (33 to 77). Deep infection occurred in two patients, problems with wound healing in five and dislocation in one. For patients with a primary malignant peri-acetabular sarcoma involving the sacroiliac joint, we believe that this new prosthesis is a viable option for reconstruction of the bony defect left following resection of the tumour. It results in a satisfactory functional outcome with an acceptable rate of complications.

Significance of age related changes in lumbosacral pedicle of adolescent / 局解手术学杂志

Objective To study the pedicle of lumbosacral developmental patterns and aging characteristics by means of studying the ado-lescents aging from 12~18 years old,and provide the basis for image and three-dimensional analysis of the treatment of spinal diseases. Meth-ods Select the 30 normal spines of adolescents without any the problems of nervous system,who did thin spiral CT scan of lumbosacral verte-brae. The original data in the form of DICOM were put into three-dimensional software to do the relevant measurement and analyzed according to gender and age. Results There were no significant differences between the pedicle of lumbosacral E/F angle and DSP /DNP and these differ-ences were not influenced by age and gender(P>0. 05). The physical development of human increases gradually with age and has some signifi-cant differences. Conclusion A regular change process and operation in the region value in patients with lumbarsacrum is displayed. But it must be combined with the results of individual imagine and the technology of reverse engineering and the support of rapid prototype manufactur-ing. Only in this way can it meet the satisfaction of individualized treatment.

Clinical analysis of posterior vertebral pedicle nail fixed injury treatment of thoracolumbar fractures in 48 cases / 重庆医学

Objective To investigate the injury posterior vertebral pedicle nail fixed treatment of thoracolumbar fractures of the clinical efficacy and safety .Methods Forty-eight cases of thoracolumbar fractures were treated by the posterior vertebral pedicle screw fixation ,according to cases decompressive laminectomy ,underwent intertransverse fusion treatment .Postoperative follow-up of 1 year ,preoperative ,postoperative 3 months ,after 1 years of vertebral compression rate ,Cobb Angle were compared .Results Forty-eight patients with postoperative 3 months and 1 year after injury postoperative spinal vertebral body compression rate were significantly decreased compared with preoperative (P<0 .05);After 3 months and 1 year after the Cobb Angle were markedly sig-nificant reduction than preoperative(P<0 .05) .X-ray showed all fractures were obtained good reduction ,internal fixation with no looseness or breakage ,no protruding after spinal deformity ,neural function were all in 1 -3 level recovery .Conclusion Posterior vertebral pedicle injury by nail fixed treatment of thoracolumbar fractures with fixed reliable ,reset effect is good .

Analysis of surgical treatment of 205 cases of spinal fracture / 中国医师杂志

Objective To discuss the surgical treatment of spinal injury, and provide insights on key points and related issues for operations. Methods Two hundred and five cases of spinal fracture were treated through posterior surgical treatment. Under C-arm X-ray monitoring, surgeries had been operated on pedicle screws insertion, vertebral canal decompression, over-extending reduction position, and placed the connecting rod, knocked in the bone graft and finally transplanted the paraspinal bone. Results After operations , the height and morphology of vertebral bodies and spinal physiological curvature were basically recovered analyzed by X ray examination. The follow-up results (in the average of 14 to 36 months) indicated that there were 4 cases of delayed infection, 7 cases of loosen screw, 6 cases of broken screw (14 screws)and 1 case of broken stick, with no secondary nerve injury or other syndromes. Conclusion The vertebral pedicle screw internal fixation manipulated easily, which could sufficiently enlarge vertebral canal in order to decompression. In addition, during the operation, together with over-extending reduction position is beneficial to regain the height of fractured vertebral bodies.

Progress in research on fixation with calcium phosphate cement strengthening screw / 中华创伤骨科杂志

When the patients with senile or secondary osteoporosis are treated with screw fixation, the screws are likely to get loose or pulled out. Polymethylmethacrylate (PMMA) can enhance screw fixation strength to some extent in clinic, but PMMA has such disadvantages as irresorbability, polymeric heating effect and toxic reaction so that its clinical application is limited. Calcium phosphate cement, however, has drawn much attention because it gets rid of the shortcomings of PMMA. This article introduces recent progress made in research on fixation with calcium phosphate cement enhancing screw.

Treatment of unstable upper and middle thoracic vertebrae fractures with vertebral pedicle screw / 中华创伤杂志

Objective To study the clinical effect of pedicle screw fixation in treatment of unstable upper and middle thoracic vertebrae fractures. Methods A retrospective study was performed on 17 cases of unstable upper and middle thoracic vertebrae fractures treated with vertebral pedicle screw system (GSS 全称in 11 cases and USS 全称in six) fixation, posterolateral bone grafting and fusion from March 2001 on. There were one case of T_3, two T_4, two T_5, four T_6, six T_7 and two T_8. Of all, nine cases were with compression fractures, five with fracture-dislocation and three with burst fractures. Results All cases were followed up for 10-38 months (average 21.1 months). During the follow up, the anterior vertebral body height was restored from preoperative 40% to postoperative 91%. Except for four screw malpositions, there was no postoperative neurologic deterioration, screw loose or breakage of the internal fixation, or loss of the normal spine curve and the spinal height of the injured vertebra. Conclusions Pedicle screw fixation is an effective way for treating unstable upper and middle thoracic vertebrae fractures. Correct placement depend on a comprehensive familiarity of pedicle anatomy, appropriate pedicle diameter and entry point and depth can avoid potential risks in placing pedicle screws into the upper and middle thorax.

Vertebroplasty with vertebral pedicle screw plus calcium sulfate cement injection treats thoracolumbar vertebrae fractures:report of 28 cases / 第三军医大学学报

Objective To evaluate the clinical efficacy of vertebroplasty using vertebral pedicle screw technique combined with calcium sulfate cement injection in the treatment of thoracolumbar vertebrae fractures.Methods Twenty-eight patients with thoracolumbar vertebrae fractures admitted in our department in recent 2 years were enrolled in this study,including 21 cases of type A,3 cases of type B,and 4 cases of type C.All patients were fixed with vertebral pedicle screw,and then verteplasty was performed using calcium sulfate cement injection.Results All patients were followed up for an average time of 16 months.Within the follow-up,there was no complication noted,such as loosening or breakage of internal fixation,chronical lumbar back pain,and loss of effected vertebral height.Artificial bones injected into vertebrae were absorbed in about 3 months.Conclusion Vertebroplasty using vertebral pedicle screw technique combined with calcium sulfate cement injection is an effective and safe procedure for thoracolumbar vertebrae fractures,which renders it possible to bear weight early and to maintain corrected vertebral height postoperatively.

Computer-assisted Fluoroscopic Navigation Guiding the Treatment of Thoracolumbar Burst Fractures with CPC Vertebroplasty and Short-segment Vertebral Pedicle Screw Fixation / 中国医师杂志

Objective To explore the efficacy of computer-assisted fluoroscopic navigation to guide the treatment of thoracolumbar burst fractures. Methods 18 patients with thoracolumbar unstable fractures were treated with short-segment vertebral pedicle screw fixation guided by computer-assisted fluoroscopic navigation, and fractures were reinforced with CPC cement vertebroplasty. Postimplantatively, the implants' images-error between virtual image of fluoroscopy and X-ray image was measured. Results The implant's location was excellent. All patients were allowed sitting-up or bearing body weight one week after operation. The vertebral height restored 40% postoperatively. 12 months after operation the vertebral height only changed 0.15%. Dynamic X-ray films showed no abnormal segment instability and no instrument breaking. Conclusion Using computer-assisted fluoroscopic navigation to guide the treatment of thoracolumbar burst fractures with CPC vertebroplasty and short-segment pedicle srew fixation could determine the internal fixation approach and let implants to the precise position by one time of X-ray image. It increases the security of pedicle screw fixation and vertebroplasty.