Anterior Posterior Fixation Research Articles

Implantation of S1AIS has priority as a sacroiliac joint fixation technique.

The sacral alar-iliac screw (SAIS) fixation technique has evolved from spinopelvic fixation which originated from S2AIS to sacroiliac joint fixation, with more reports regarding its application of S2AIS than S1AIS. However, there is a lack of comparative evidence to determine which technique is superior for sacroiliac joint fixation. This study aimed to determine which of the screws was superior in terms of implantation safety and biomechanical stability for sacroiliac joint fixation. CT data of 80 normal pelvises were analyzed to measure the insertable range, trajectory lengths and widths of both S1AIS and S2AIS on 3D reconstruction models. Φ 6.5mm and 8.0mm screws were implanted on the left and right sides of fifty 3D printed pelvic models respectively to observe for breach of screw implantation. Ten synthetic pelvis models were used to simulate type C Tile injuries, and divided into 2 groups with an anterior plate and posterior fixation using one S1AIS or S2AIS on each side. The stiffness and maximum load of the plated and fixated models were measured under vertical loading. The trajectory lengths and widths of the S1AIS and S2AIS were similar (p > 0.05) and there was no breach for Φ 6.5mm SAIS. However, both the insertable range and trajectory length on the sacral side of S2AIS (234.56 ± 10.06mm2, 40.97 ± 2.81mm) were significantly less, and the breach rate of the posterior lateral cortex of the Φ 8.0mm S2AIS (46%) was significantly higher than the S1AIS (307.55 ± 10.42 mm2, 42.16 ± 3.06mm, and 2%, p < 0.05). The stiffness and maximum load of S2AIS were less than S1AIS but the difference was not statistically significant (p > 0.05). S1AIS and S2AIS have similar screw trajectories and stability. However, S1AIS has a larger insertable range, less breach of the posterior lateral sacral cortex and longer trajectory length on the sacral side than S2AIS, which indicates S1AIS has higher implantation safety and a trend of better mechanical performance over S2AIS for sacroiliac joint fixation. Furthermore, S2AIS with an excessively large diameter should be used with caution for sacroiliac joint fixation.

Comparison of the operation safety and biomechanical stability of sacral alar-iliac vs. sacroiliac screws in the fixation of sacroiliac joint in simulated models of low bone density

BackgroundSacral alar-iliac screws (SAISs) have been used for sacroiliac joint and are superiority to traditional sacroiliac screws (SISs) in patients with low bone density. The aim of this study was to investigate the operation safety and biomechanical stability of the SIS, transsacral-transiliac screw (TSTIS), S1AIS and S2AIS in the treatment of sacroiliac joint in simulated models of low bone density. MethodsCT data from 80 normal pelvic structures were employed to measure the anatomical parameters, including the safety zones of the S1AIS and S2AIS at the insertion point and the trajectory lengths of the SIS, TSTIS, S1AIS and S2AIS. Sixteen synthetic pelvises with simulated osteoporotic bone structure were used to simulate type C Tile lesions and divided into 4 groups with an anterior plate and posterior fixation using one of the following: 1) one SIS on each side, 2) one TSTIS fixing both sides, 3) one S1AIS on each side, or 4) one S2AIS on each side. The stiffness and maximum load of the specimens were analyzed using a biomechanical machine under vertical loading. ResultsThe safety zone of S1AIS was larger than that of S2AIS (p < 0.05). The TSTIS had the largest trajectory length, followed by the S1AIS and S2AIS, and the SIS had the smallest trajectory length (p < 0.05). However, the lengths of the TSTIS (26.1 ± 1.7 mm) and SIS (27.8 ± 1.8 mm) trajectories on the short side (the iliac side) were smaller than those of S1AIS (40.4 ± 3.8 mm) and S2AIS (39.1 ± 3.8 mm), thus indicating significant differences (p < 0.05). The stiffness and maximum load of S1AIS and S2AIS were similar and the greatest, followed by TSTIS and SIS (p < 0.05). ConclusionThe stability of S1AIS and S2AIS is similar, both stronger than that of SIS and TSTIS, which have shorter lengths of the screw trajectories on the ilium side. However, the safety zone of S2AIS at the insertion point is smaller than that of S1AIS. Therefore, considering both safety and stability, S1AIS is the preferred choice for fixation of sacroiliac joint dislocation in simulated models of low bone density.

Does sequential examination under anaesthesia provide a reliable method to determine a management plan for unstable lateral compression pelvic ring injuries? a prospective study.

To assess the reliability of sequential examination under anaesthesia (EUA) to determine pelvic instability and to evaluate radiological and functional outcomes in unstable lateral compression (LC) injuries. A prospective case series study was conducted from 2020 to 2022 at a university hospital on 43 cases with LC injuries that met the inclusion criteria. Sequential EUA was carried out in three steps. Posterior-only fixation or anterior-posterior fixation was done according to the algorithm. Each patient was followed up for at least 12months, both radiologically and functionally. Forty cases proved unstable and were fixed. None showed secondary displacement in the anterior-posterior fixation group. However, five cases (19.2%) of the posterior-only fixation group showed secondary displacement with a mean of 5.9mm. Four cases of them had tetra-ramic injuries. There is a high tendency for secondary displacement at 14.5mm or more preoperative displacement of the rami. Patients with secondary displacement showed comparable functional outcome scores to patients without secondary displacement. Posterior-only fixation showed shorter operative time, lesser radiological exposure, blood loss and iatrogenic nerve injury than anterior-posterior fixation. EUA is a reliable method to determine pelvic instability and management plan for LC fractures with unilateral anterior ring injury. Anterior-posterior fixation is needed if there is a tetra-ramic fracture or initial anterior ring displacement of 14.5mm or more, irrespective of EUA.

Combined Anterior-Posterior Versus Posterior-Only Fixation of Stress-Positive Minimally Displaced Lateral Compression Type 1 (LC1) Pelvic Ring Injuries.

To compare hospital outcomes and late displacement between stress-positive minimally displaced lateral compression type 1 (LC1) pelvic ring injuries treated with combined anterior-posterior versus posterior-only fixation. Retrospective comparative cohort. Urban level one trauma centerPatients/Participants: LC1 injuries managed operatively. Anterior-posterior vs. posterior-only fixation. Physical therapy (PT) clearance, discharge location, hospital length of stay (LOS), inpatient morphine equivalent doses (MED), fracture displacement at follow-up. Groups were similar in demographic and injury characteristics (age, high energy mechanism, ASA score, stress displacement, and rami/sacral fracture classifications). Anterior-posterior fixation resulted in longer operative times (median difference (MD): 27.0 min., 95% confidence interval (CI): 17.0 to 40.0, p<0.0001) and had a trend of increased estimated blood loss (MD: 10 mL, CI: 0 to 30, p=0.07). Patients with anterior-posterior fixation required less inpatient MEDs (MD: -180.0, CI: -341.2 to -15.0, p=0.02), were more likely to clear PT by discharge (100% vs. 70%, proportional difference (PD): 30%, CI: 2.0% to 57.2%, p=0.02), were less likely to discharge to rehabilitation facilities (0% vs. 30%, PD: 30%, CI: 2.0% to 57.2%, p=0.02), and had a trend of less days to clear PT after surgery (MD: -1, CI: -2 to 0, p=0.09) and decreased LOS (MD: -1, CI: -4 to 1, p=0.17). Late fracture displacement did not differ between groups. Anterior-posterior fixation of LC1 injuries was associated with an improved early hospital course-specifically, reduced inpatient opioid use and an increased number of patients who could clear PT and discharge home. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Surgical Treatment for Displaced Odontoid Synchondrosis Fracture: A Retrospective Case Series Study.

Retrospective cohort study. Odontoid synchondrosis fracture is rare, and there is a paucity of literature on its surgical treatments. This case series study analyzed patients treated with C1 to C2 internal fixation with or without anterior atlantoaxial release and discussed the clinical effectiveness of the procedure. Data were retrospectively collected from a single-center cohort of patients who had undergone surgical treatments for displaced odontoid synchondrosis fracture. The operation time and blood loss volume were recorded. Neurological function was assessed and classified using the Frankel grades. The odontoid process tilting angle (OPTA) was used to evaluate fracture reduction. Fusion duration and complications were also analyzed. Seven patients (1 boy and 6 girls) were included in the analysis. Three patients underwent anterior release and posterior fixation surgery, and the other 4 underwent posterior-only surgery. The fixation segment was C1 to C2. The average follow-up period was 34.7 ± 8.5months. The average operation time was 145.7 ± 45.3min, with an average blood loss volume of 95.7 ± 33.3mL. The OPTA was corrected from 41.9° ± 11.1° preoperative to 2.4° ± 3.2° at the final follow-up (P < .05). The preoperative Frankel grade of 1 patient was grade C, of 2 patients was grade D, and of 4 patients was grade E. The neurological function of the patients in grade C and grade D recovered to grade E at the final follow-up. None of the patients developed a complication. All the patients achieved odontoid fracture healing. Posterior C1 to C2 internal fixation with or without anterior atlantoaxial release is a safe and effective method for treating young children with displaced odontoid synchondrosis fracture.

The Effect of Anterior-Only, Posterior-Only, and Combined Anterior Posterior Fixation for Cervical Spine Injury with Soft Tissue Injury: A Finite Element Analysis

This finite element analysis aimed to investigate the effects of surgical procedures for cervical spine injury. A three-dimensional finite element model of the cervical spine (C2-C7) was created from computed tomography. This model contained vertebrae, intervertebral discs, anterior longitudinal ligament, and posterior ligament complex. To create the cervical spine injury model, posterior ligament complex and anterior longitudinal ligament at C3-C4 were resected and the center of the intervertebral disc was resected. We created posterior-only fixation (PF), anterior-only fixation (AF), and combined anterior-posterior fixation (APF) models. A pure moment with a compressive follower load was applied, and range of motion, annular/nucleus stress, instrument stress, and facet forces were analyzed. In all motion except for flexion, range of motion of PF, AF, and APF models decreased by 80%-95%, 85%-93%, and 97%-99% compared with the intact model. C3-C4 annulus stress of PF, AF, and APF models decreased by 28%-72%, 96%-100%, and 99%-100% compared with the intact model. Facet contact forces of PF, AF, and APF models decreased by 77%-79%, 97%-99%, and 77%-86% at C3-C4 compared with the intact model. Screw stress in the PF model was higher than in the APF model, and plate stress in the AF model was lower than in the APF model, but bone graft stress in the AF model was higher than in the APF model. Cervical stabilization was preserved by the APF model. Regarding range of motion, the PF model had an advantage compared with the AF model except for flexion. An understanding of biomechanics provides useful information for the clinician.

Effect of different fixation methods on biomechanical property of cervical vertebral body replacement and fusion

BackgroundThe main purpose of this study was to examine the effect of different fixation methods (anterior fixation, self-stabilizing fixation and anterior-posterior fixation) on biomechanical property of vertebral body replacement and fusion. MethodsThree finite element models of cervical vertebral body replacement and fusion were established. The implanted models included artificial vertebral body and fixation system, and the loads imposed on the models included 75 N compression load and 1 Nm moment load. FindingsFor anterior-posterior fixation, the cervical load was mainly transmitted by the posterior pedicle screw and rod (more than 50%), and the stress shielding problem was the most significant than the self-stabilizing and anterior fixation. Self-stabilizing fixation was more helpful to the fusion of implant and vertebrae, but the higher risk of vertebral body collapse was worthy of attention if the cervical spine with osteoporosis. The stress of bone was mainly concentrated around the screw hole. The maximum stress (20.03 MPa) was lower than the yield stress of cortical bone and the possibility of fracture around the fixation device of cervical spine was low. The anterior fixation could meet the requirement of vertebral body replacement and fusion, and the addition of posterior pedicle screws and rods might obtain better treatment in cases of severe spine injury or osteoporosis. InterpretationThe findings of this study may provide guidance on clinical treatments for choosing more appropriate fixation methods for different patients.

Hot topic of cranial vertebral surgery: the surgical plan of type A basilar invagination

Regarding the treatment of type A basilar invagination, there is a debate between the combination of anterior and posterior surgery and posterior fixation. The author's personal opinion on the hot topic of cranial vertebral surgery: the surgical plan of type A basilar invagination is expressed in this article. Overall, the combined anterior-posterior approach is applicable in almost all cases of type A basilar invagination, regardless of how severe atlantoaxial dislocation, and simple posterior surgery is only in cases where atlantoaxial dislocation is not very severe. The anterior-posterior combined surgery has two incisions, and the risk of postoperative infection is higher than for posterior surgery alone. If the patient has no spinal cord symptoms, only posterior surgery is acceptable, even if no anatomical reduction can be achieved. If there is a more severe spinal cord dysfunction, or a large syringomyelia, anterior atlantoaxial release is necessary to ensure achieving anatomical reduction and restoring the normal morphology of the cervical spinal cord.

33. Comparison of the biomechanics of lumbar spine instrumented with standalone interbody fixation constructs vs interbody with supplemental fixation: a finite element investigation

<h3>BACKGROUND CONTEXT</h3> Low fusion rates and cage subsidence have been reported as the main drawbacks of lumbar fixation with static interbody cages. Although several clinical and biomechanical studies have evaluated the efficacy of 360 interbody fixation constructs (anterior cage plus posterior fixation), no study has reported the biomechanical comparison between such constructs and more novel techniques which use standalone fixation implants. A cadaver validated computational model of lumbar spine was used to compare the biomechanics of spine instrumented with 360 fixations vs standalone cage and screw and cage with lateral plate systems. <h3>PURPOSE</h3> To compare the mechanical stability of different interbody fixation techniques in lumbar spinal segments with standalone interbody vs static cage with posterior fixation or lateral plate system. <h3>STUDY DESIGN/SETTING</h3> Finite element modeling. <h3>OUTCOME MEASURES</h3> Range of motion across instrument segments and load sharing on vertebral endplate. <h3>METHODS</h3> An experimentally validated finite element (FE) model of L1-pelvic segment was used to simulate ALIF and LIF lumbar fixation techniques including: ALIF cage at L5-S1 plus posterior screw-rod fixation (360 construct) vs ALIF standalone (screw through the cage). LIF cage at L4-L5 vs LIF cage with integrated two-hole lateral plate system. 4WEB Medical's Truss ALIF (27mm x 25mm), Lateral Truss (22mm X 5mm) cages and 2-hole integrated plate systems were used for simulation of the surgical procedure. For 360 constructs, a generic posterior rod and screw system was used. All models were subjected to a 400N compressive pre-load followed by an 8Nm moment to simulation flexion-extension, left and right bending and axial rotation motions. The segmental kinematics and the load sharing at the inferior endplate were compared among cases. <h3>RESULTS</h3> The segmental motion in standalone ALIF construct was 1.1°(Flex-Ext), 0.9° (LB) and 0.4° vs 0.8°, 0.8° and 0.6° in 360 ALIF in the same planes of motion. When comparing lateral cases, the motions were 1.2° (Flex-Ext), 1.4° (LB) and 0.5° (AR) in lateral cage with plate vs 0.9°, 1.0° and 0.8° in the 360 lateral construct for the same loads. The peak stresses in extension for the LIF stand-alone cage were somewhat higher than the posterior instrumented cases, but not significant. When comparing the mechanical stress on the inferior endplate of the index segment, the standalone ALIF had almost 20% higher peak stress compared to the 360 ALIF. In the lateral construct, the cage-plate segment experienced 15% lower stresses on the endplate compared to the 360 lateral construct. <h3>CONCLUSIONS</h3> Our data suggest that standalone ALIF cage with screw through the cage is able to provide kinematic stability in the fixation construct comparable to the cage plus posterior fixation, although the 360 construct is able to provide slightly more stability in the sagittal plane. Also, the standalone cage results in higher stresses applied to the endplate compared the cage in 360 constructs. The lateral cage with integrated plate had superior stability in axial rotation compared to the 360 lateral construct. The loads on the endplate were also slightly lower compared to the 360-fixation case. Standalone ALIF and LIF with lateral plate are biomechanically effecient alternatives to 360-fixation constructs at least under the controlled conditions analyzed in the present study. Clinical data are required to support the findings and define the further role and application of standalone cages. <h3>FDA DEVICE/DRUG STATUS</h3> 4WEB ALIF Truss System (Approved for this indication), 4WEB Lateral Plate System (Approved for this indication), 4WEB Lateral Truss System (Approved for this indication)

P152. Is short segment fracture fixation appropriate for AO spine type B and C injuries?

<h3>BACKGROUND CONTEXT</h3> The AO Spine Classifications are associated with a hierarchical injury severity score. "Type A" fractures represent the most stable injuries and "Type C" represent the most severe and unstable injuries. "Three column" subaxial cervical spine and thoracolumbar injuries are designated as Type B (tension band) and Type C (fracture dislocation). Although the load sharing classification describes burst type fractures, Type B and C injuries are often minimally comminuted but grossly unstable due to "three-column" disruption. Therefore, the load sharing classification may not be appropriate to guide short- or long-segment fixation. <h3>PURPOSE</h3> To identify if construct length affects the rate of surgical complications or instrumentation revision following Type B and C subaxial or thoracolumbar injuries. <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort study. <h3>PATIENT SAMPLE</h3> All patients with cervical or thoracolumbar Type B and Type C injuries between 2006-2021 were identified from a prospectively collected database. Only patients who underwent operative intervention were included. <h3>OUTCOME MEASURES</h3> Surgical complications (persistent cerebrospinal fluid leak, wound dehiscence, epidural hematoma, surgical site infection) and reoperations (instrumentation revision and/or exchange). <h3>METHODS</h3> Patients were divided based on the number of levels instrumented above and below the injured level (>2 levels (long-segment) versus < 2 levels (short-segment)). Patient demographics, surgical characteristics and clinical outcomes were collected and compared. Independent t-tests or Mann-Whitney U tests compared continuous variables, while Pearson's chi-square tests compared categorical variables. Bivariate logistic regression measured the effect of fixation construct length (long-segment fixation) on the likelihood of having a surgical complication and reoperation for instrumentation revision and/or exchange. Alpha was set at P<0.05. <h3>RESULTS</h3> A total of 180 patients representative of 187 fractures were included. Of the 187 injuries, 69 (36.9%) underwent long-segment fixation. Patients who underwent long-segment fixation were older (61.1 vs 51.5 years, p=0.005), were more likely to have comorbid ankylosing spondylitis (AS) or diffuse idiopathic skeletal hyperosteosis (DISH) (47.8% vs 21.2%, p<0.001), and were more likely to have an injury that involved a thoracic vertebra (53.6% vs 30.5%, p=0.008). Further, patients who underwent long-segment fixation were more likely to undergo posterior-only fixation (85.5% vs 60.2%, p<0.001) in comparison to anterior-only and combined anterior-posterior fixation. There was no significant difference in the proportion of long-segment versus short-segment constructs that included bilateral, unilateral or no pedicle screws within the injured vertebrae (p=0.371). Bivariate logistic regression demonstrated that a long-segment fixation construct had a non-significant increase in complication rates (OR=2.08, p=0.176) and reoperations for instrumentation revision or exchange (OR=2.99, p=0.142). We subanalyzed the 58 fractures with AS/DISH compared to the 129 fractures without AS/DISH. Injuries with AS/DISH had a mean 2.57+ 1.01 and 2.34 + 0.81 levels instrumented above and below the injury compared to injuries without AS/DISH, mean 1.97 + 1.04 and 1.90 + 0.96 levels instrumented above and below the injury (p<0.001), respectively. However, there was no difference in the rate of surgical complications (8.62% vs 7.75%, p=0.780) or instrumentation revision (6.90% vs 3.10%, p=0.256) between the two groups based on construct length. <h3>CONCLUSIONS</h3> Long-segment fixation of Type B or C subaxial cervical spine or thoracolumbar spine injuries resulted in a non-significant increase in complications and spine reoperations for instrumentation revision. Instrumentation technology has improved since the load sharing classification. This exploratory study suggests short segment fixation may be appropriate even for unstable spine fractures. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Mother's iliac bone graft for severe collapsed lumbar tuberculosis: A case report

AbstractEarly diagnosis of spinal tuberculosis in young children is difficult due to atypical clinical features. We report a case of lumbar tuberculosis with abscess of the psoas major muscle in a 4‐year‐old child. Spinal reconstruction was challenging due to the involvement of multiple vertebral levels. The child complained of lumbar and back pain. Preoperative magnetic resonance imaging (MRI) revealed bone destruction of the L1–L3 vertebral body and abscess formation of the psoas major muscle. The child underwent excision of the vertebral lesions and a fresh iliac bone graft from his mother through an anterior approach and posterior fixation with T12–L1 and L4–L5 pedicle screws. At the 15‐month follow‐up, the patient had good clinico‐radiologic outcomes with evidence of bony fusion. No functional impairment of lumbar movements was found through physical examination during the follow‐up period. The report highlights the diagnostic dilemma of early childhood spinal tuberculosis due to lesions seen both on radiology and during surgery and discusses challenges in management of the disease and the relevant literature. The mother's iliac bone graft we describe can be a viable option in very young children with severe vertebral bone destruction requiring reconstruction by surgical procedure.

РЕКОНСТРУКТИВНЫЕ И СТАБИЛИЗИРУЮЩИЕ ВМЕШАТЕЛЬСТВА В КОМПЛЕКСНОЙ ТЕРАПИИ ПАЦИЕНТОВ С СОЛИТАРНЫМИ МЕТАСТАЗАМИ ПОЗВОНОЧНИКА

Abstract. Introduction: The problem of diagnosis and treatment of patients with oncological pathology of the spine is relevant due to treatment complexity and the increasing number of patients’ morbidity. Secondary neoplastic processes are common in spine because of its anatomy, physiological features, complex biomechanics and enhanced vascularization. The main clinical manifestations of metastatic lesions of the spine are pain and neurological deficit. The development of spinal cord compression and pain syndrome leads to a sharp deterioration in the quality of life in patients with metastatic lesions of the spine. Despite the progress made in modern surgery of patients with oncological diseases with metastasis to the spine, mortality rates after surgery reaches 6.3% and complications appear in 23% of cases. Aim: Improving the results of treatment of patients with solitary spinal metastases and spinal cord compression. Methods and materials: Between 2010 and 2018, patients with spinal neoformations (N=240) received surgical treatment at Traumatology Unit of North-Western State Medical University named after I.I. Mechnikov. All patients were put into the categories according to their sex, age, histologic type and location of tumors. We assessed patients’ pain severity (BAIII), neurologic status (Frankel scale) and life span (by Kaplan-Meier method). Results: The study presents the analysis of the results of complex therapy of 183 patients with solitary metastases of the spine, who underwent the surgical stage of treatment. For these patients the epidemiological structure and the main clinical and radiological characteristics of solitary metastatic lesions of the spine were determined, a comparative assessment of the effectiveness of various options for surgical interventions in the complex treatment was carried out. To do so, all patients of the primary cohort were divided into 2 groups depending on the volume of surgery. The first group included 54 patients who underwent a radical resection of the affected vertebra in a single block with prosthetics of the anterior support column and posterior instrumental fixation. The second group included 129 patients after palliative decompressive and stabilizing operations from the posterior approach. Conclusion: There were no statistically significant differences between the two studied methods of surgical treatment in terms of the dynamics of the level of pain syndrome, regression of neurological deficit and life expectancy. When choosing the tactics of surgical treatment of patients with solitary spinal metastases, the main method is decompressive and stabilizing interventions, which helps to reduce the risk of surgical complications, improve the quality of life of the patient and continue the complex treatment of the underlying disease.

What's New in Spine Surgery.

What's New in Spine Surgery.

Management of LC Type I (LC-1) Pelvic Injuries with Complete Sacral Fracture: Comparison of Solitary Anterior Fixation with Combined Anterior-Posterior Fixation.

Background Management of LC-1 type pelvic injuries, particularly in patients with complete sacral fracture (LC-1 PICSF, OTA type 61-B2.1), remains controversial. Specific indications for solitary fixation remain unclear, and there is a paucity of outcomes data in comparison to combined fixation. We undertook a retrospective study in patients with LC-1 PICSFs to compare outcomes between solitary anterior fixation and combined anterior-posterior fixation. Methods A retrospective cohort study was conducted with enrollment from 2016 to 2018 at a single tertiary-referral center in China. Adults with operatively managed LC-1 PICSFs were enrolled. Patients with sacral displacement < 1 cm as assessed by axial CT received solitary anterior ring fixation (group A); patients with displacement ≥ 1 cm received combined fixation of both the anterior and posterior rings (group B). Reduction was confirmed by manipulation under anesthesia. Patients followed up for at least 24 months postoperatively. Primary outcome was function (Majeed score). Secondary outcomes included intraoperative characteristics, pain (VAS score), quality of fracture reduction (Tornetta and Matta radiographic grading), rate of nonunion, early weight-bearing status, and complication rate. Results 68 (89%) of 76 enrolled patients completed follow-up. Patients in group A exhibited improved operative times, less time under fluoroscopy, and less blood loss as compared to group B. There were no significant differences between groups A and B regarding quality of fracture reduction, rate of union, functional outcomes, or rate of complications. Notably, group B patients were more likely to achieve full early weight-bearing. Conclusion LC-1 PFCSFs can get benefits from ORIF; the treatment algorithm should be differently made following the degree of the sacral fractures displacement. Less than 1 cm sacral fracture displacement may get good functional outcomes from solitary anterior fixation. However, for the sacral fractures displacement greater or equal to 1 cm, both the anterior and posterior pelvic rings should be surgical stabilization.

The use of a 3D-printed personalised drill guide for posterior column lag screw fixation in displaced transverse acetabular fracture: A case report.

Introduction and importanceAnterior column plate combined with posterior column screws have been effectively used for treatment of displaced transverse acetabular fractures. This article presents the use of 3D-printed technology for customising a guide template to appropriately place posterior column screw.Case presentationA 50-year-old female suffered displaced juxtatectal fracture of the right acetabulum. A personalised guide for antegrade posterior column screw placement was designed based on the data of her pelvic CT-scan. This guide and a prototype of her right acetabulum - created by mirroring the intact left acetabulum - were 3D-printed for preoperative evaluation and pre-contouring of reconstruction plate. Modified Stoppa approach and additional lateral window were used for direct reduction, anterior column plate and posterior column lag screw fixation. Post-operative CT-scan showed good reduction and nearly ideal screw position.Clinical discussionAnterior column plate and antegrade posterior column screw could provide joint stability and early mobilisation for displaced transverse acetabular fractures. However, determination of optimal entry point, direction and length for screw insertion is still technically demanding. The 3-D reconstruction images of hemipelvic specimen allowed us to identify the safe bone corridor, design a drill guide to put the proper guide pin and conduct preoperative trial. All those resulted in appropriate real screw fixation with reduction of soft tissue damage, X-ray exposure and time of operation.ConclusionThe use of 3D-printed personalised guide for posterior column screw fixation is a promising alternative option for treatment of displaced transverse acetabular fracture where 3D-navigation system is not available.

Biomechanical investigation of potential prophylactic scoliosis treatments following various sizes of chest wall resection

BackgroundA well-known problematic sequela of chest wall resections is development of scoliosis. Despite the seriousness and frequency of scoliosis following chest well resection, the etiology and biomechanical information needed to understand this progression aren't well-known. MethodsRange of motion of six specimen (C7–L2) was captured using a custom-built six degrees-of-freedom machine in each of three physiological rotation axes. Left posterior ribs were sequentially resected 7cm from the rib head, starting at the 5th rib and continuing until the 10th rib. Injured specimen were instrumented with unilateral anterior rod fixation and then with additional unilateral posterior fixation, each starting at T4 and then extended distally as ribs were resected. Relative motion between the constructs' proximal and distal ends was measured in all three axes for the intact, injured, unilateral anterior, and unilateral anterior with unilateral posterior constructs. FindingsRaw motion of the injured specimen increased in a stepwise manner as ribs were resected. Averaged across all injury sizes, the unilateral anterior construct significantly reduced motion by 47.0±13.4% in lateral bending (P=.001). The combined anterior-posterior construct significantly reduced motion by 57.6±15.9% in flexion/extension (P<.001), 70.3±12.2% in lateral bending (P<.001), and 51.1±14.5% in axial rotation (P<.001). Combined anterior-posterior fixation was significantly more stable than anterior-only fixation in flexion/extension (P=.002). InterpretationRegardless of injury size, posterior rib resection did not create significant immediate instability of the thoracic spine. Concurrent spinal stabilization was shown to maintain thoracic spine stability. Combined anterior-posterior fixation proved to be significantly more rigid than an anterior-only construct.

Comparison of One-Year Functional Outcomes and Quality of Life between Posterior Pelvic Ring Fixation and Combined Anterior-Posterior Pelvic Ring Fixation after Lateral Compression (B2 Type) Pelvic Fracture.

Background and Objectives: The treatment algorithm of lateral compression B2 type pelvic fractures are still under debate. Some authors advocate conservative treatment, while others recommend surgical approach. The clear indications for isolated anterior or posterior ring fixation or combined anterior-posterior pelvic ring fixation of B2 type fractures remain unclear. The aim of this study was to compare the functional outcomes and quality of life after isolated posterior pelvic ring fixation and combined anterior-posterior pelvic ring fixation for the treatment of B2 pelvic fractures. Materials and Methods: Patients aged 18 to 65 years with B2 type pelvic fracture hospitalized in a single trauma centre over a period of 3 years were included in the research. Based on the attending surgeon’s preference, patients were treated with isolated posterior or combined anterior-posterior pelvic fixation. The quality of life and pelvic function were assessed using SF-36 and Majeed questionnaires, respectively. Patients filled in the questionnaires twice: during the first hospitalization (concerning their pre-trauma state—timepoint I) and one-year after the injury (timepoint II). Results: A cohort of 32 patients with B2 type pelvic fracture was enrolled in the analysis: 23 (72%) were female and 9 (28%) were male. The mean age was 35.3 ± 11.9 years. In this cohort 13 (41%) patients underwent isolated posterior pelvic ring fixation (group I) and 19 (59%) patients underwent combined anterior-posterior pelvic ring fixation (group II). No statistically significant differences were observed between the groups in both timepoints concerning Majeed, SF-36 PCS and MCS scores. However, in both groups Majeed and SF-36 PCS scores were statistically significantly lower one year after pelvic fracture compared with pre-trauma state, while SF-36 MCS scores did not differ. Conclusions: No differences were found in quality of life and functional outcomes between isolated posterior pelvic ring fixation and combined anterior-posterior fixation for the treatment of B2 type pelvic fractures.

Single column plate plus other column lag screw fixation vs. both column plate fixation for anterior column with posterior hemitransverse acetabular fractures - a biomechanical analysis using different loading protocols.

Open reduction and internal fixation of both columns is considered the treatment of choice for displaced anterior column with posterior hemitransverse (ACPHT) fractures in non-geriatric patients. Plate fixation of one column combined with lag screw fixation of the other column allows to decrease operative time and approach-related morbidity compared to conventional both column plating. The aim of this biomechanical study was to evaluate whether single column plate plus other column lag screw fixation confers similar stability to both column plate fixation. Physiological loads were simulated using both the single-leg stance (SLS) as well as the sit-to-stand (STS) loading protocols. A clinically relevant ACPHT fracture model was created using fourth-generation composite hemipelves. Fractures were stabilized with three different fixation constructs: (1) anterior column plate plus posterior column screw fixation (AP+PCS), posterior column plate plus anterior column screw fixation (PP+ACS) and anterior column plate plus posterior column plate fixation (AP+PP). Specimens were loaded from 50 to 750N with a ramp of 100N/s. Fracture gap motion (FGM) and relative interfragmentary rotation (RIFR) between the three main fracture fragments were assessed under loads of 750N using an optical 3D measurement system. STS loading generally resulted in higher mean FGM and RIFR than STS loading in the AP+PCS and AP+PP groups, while no significant differences were found in the PP+ACS group. Compared to conventional both column plate fixation (AP+PP), PP+ACS displayed significantly higher FGM and RIFR between the iliac wing and the posterior column during SLS loading. No significant differences in FGM and RIFR were identified between the AP+PCS and the AP+PP group. Overall, single column plate plus other column lag screw fixation conferred similar stability to conventional both column plate fixation. From a clinical point of view, AP+PCS appears to be the most attractive alternative to conventional AP+PP for internal fixation of ACPHT fractures.

Complications of the treatment of post-traumatic deformities of the thoracic and lumbar spine using staged surgical interventions

Objective . To analyze the results of surgical treatment of post-traumatic deformities of the thoracic and lumbar spine using staged surgical interventions from the point of view of surgical safety, and to study the structure, frequency and nature of intra- and postoperative complications and intraoperative blood loss. Material and Methods . A retrospective analysis of data of 212 patients for 2015–2018 was performed. Inclusion criteria were: age over 18 years, staged surgical interventions including anterior spinal fusion and posterior internal fixation performed in one surgical session for post-traumatic deformities of the thoracic and lumbar spine. Patient demographic data and surgical intervention protocols were studied taking into account surgical approaches, duration of operations and blood loss. Intraoperative and postoperative complications up to 6 weeks after surgery were taken into account. Intraoperative blood loss was studied both as the absolute volume and as the percentage of circulating blood volume (CBV). Results . Complications after staged surgical correction of post-traumatic deformities were recorded in 14.2 % of patients, including intraoperative complications in 3.3 % of cases, and postoperative complications in 10.9 %. The most common complications were surgical site infections, usually after posterior approach, and pneumonia. The number of neurological complications was 1.4 %. Complications were more frequent after three-stage surgical interventions than after two-stage ones. The lumbar spine deformity correction was associated with higher complication rate than that in the thoracic spine. Intraoperative blood loss in the study group was 562.2 ± 504.7 ml. The most significant blood loss, over 30 % of the СBV, was noted in 13 (6.1 %) patients. Using of minimally invasive transpedicular fixation during the staged surgical intervention provided the least number of infectious wound complications and the smallest amount of intraoperative blood loss. Conclusion . Staged surgical intervention for the correction of post-traumatic deformity of the thoracic and lumbar spine is a safe method of surgical treatment.

Comparison of lag screw fixation on posterior malleolar fractures in different directions and screw-related complication

Objective To compare the effects of indirect reduction, percutaneous anterior posterior screw and direct reduction, posterior anterior screw in the treatment of posterior malleolus fracture. Methods A retrospective analysis was made on 58 patients with posterior malleolus fracture treated by cannulated screw fixation from January 2013 to December 2017 in the Department of Orthopedics, Affiliated Hospital of Guangdong Medical University.They were divided into anterior and posterior screw group (26 cases) and posterior and anterior screw group (32 cases) according to different treatment methods.The incidence of poor screw position and other complications were compared between the two groups.Health status and ankle function at the last follow-up were compared between the two groups. Results The incidence of screw malposition in the anterior and posterior screw fixation group was 23.08%(6/26), which was significantly higher than that in the posterior screw fixation group was 3.85%(1/32). The difference between the two groups has statistically significant (χ2=5.381, P=0.020); there was no significant difference in other complications such as infection, traumatic arthritis, bone nonunion (all P>0.05). At the last follow-up, the OMA scores of AP group were (80.70±8.16)and PA group were(75.23±9.33), There were significant differences between the two scores(t=2.240, P=0.029), the AOFAS scores of AP group were (80.57±7.25) and PA group were(75.38±10.19), There were significant differences between the two scores(t=2.110, P=0.039). Conclusion The Indirect reduction and percutaneous anterior and posterior screw treatment have a high incidence of malposition of the screw, which has an impact on ankle function.Direct reduction and posterior and anterior screw fixation can significantly reduce the incidence of malposition of the screw and obtain better functional results. Key words: Posterior malleolus fracture; Indirect reduction; Poor screw position; Ankle function