Surgical Screws Research Articles

Effect of repeated steam sterilizations on insertional torque, torque to failure, and axial pullout strength of 3.5-mm and 2.0-mm cortical bone screws.

The objective of this study was to determine the effects of repeated steam sterilization cycles on the biomechanical properties of surgical screws. 42 3.5-mm and 42 2.0-mm self-tapping, cortical screws were divided into 3 groups per size and underwent autoclave sterilization for 1 (G1), 50 (G50), or 100 (G100) cycles and testing from August 2018 through June 2021. Sixty screws were then inserted into canine cadaver femurs, and biomechanical properties were measured, including peak insertional torque, torque to failure, and pullout strength, each normalized to cortical thickness. Scanning electron micrographs were taken from 24 screws, and images were blindly analyzed by 5 trained examiners. The mean normalized insertion torque for 3.5-mm screws was significantly different between G1 and both G50 and G100. The mean normalized torque to failure for 3.5-mm screws was significantly different between G1 and both G50 and G100. Axial pullout testing was found to be significantly different for 2.0-mm screws between G1 and G100. Scanning electron micrographs surface scoring identified a significant difference in 3.5-mm screws at the screw tip. The results indicate that biomechanical changes occur with repeated steam sterilizations. Specifically, peak insertional torque and torque to failure are decreased with increased sterilizations for 3.5-mm screws, whereas 2.0-mm screws were altered in pullout testing after 100 sterilizations. It is suspected that numerous sterilizations negatively alter the physical-mechanical properties of certain screw sizes. The biomechanical properties of the bone-implant interface could negatively be affected by multiple steam sterilizations during clinical setting.

Evaluation of stress and strain on surgical screws and plates in mandibular trunk fractures at different positions of plates and screws: Finite Element Analysis

Introduction: To determine the most appropriate method for placement of plates and screws in terms of stress in mandibular body fractures using finite element analysis.
 Methods: First a model of the mandible reconstructed with Mimics software. This study employed various methods, including plates positioned parallel to the inferior border of the mandible with screws perpendicular to the bone; plates parallel to the inferior border of the mandible fixed with screws oriented at a 45-degree to the fracture line; plates positioned perpendicular to the fracture line fixed with screws perpendicular to the bone; plates perpendicular to the fracture line and fixed with screws oriented at a 45-degree to the fracture line. Then the software measured the stress within the screws and plates in each condition under the maximum bite force.
 Results: It was observed that in cases of favorable horizontal fractures, the stress exerted on the plates and bones is greater when the plates are aligned parallel to the lower border of mandible, compared to when the plates are positioned perpendicular to the fracture line. In the study of unfavorable horizontal fractures, when the plates were fixed perpendicular to the fracture line, higher magnitudes of stress were recorded compared to the stress observed in the plates positioned parallel to the inferior border of the mandible.
 Conclusion: In cases of mandibular body fractures with favorable horizontal orientations, the use of fixation techniques involving plates perpendicular to the fracture line is preferred due to the reduced stress exerted on the plates. In the unfavorable horizontal fractures, the stress levels do not exhibit significant variation between different fixations. Finally, it is not advisable to utilize screws positioned at a 45-degree angle to the fracture line, as it can lead to an increase in the displacement of the plates.

Advancing 6-DoF Instrument Pose Estimation in Variable X-Ray Imaging Geometries.

Accurate 6-DoF pose estimation of surgical instruments during minimally invasive surgeries can substantially improve treatment strategies and eventual surgical outcome. Existing deep learning methods have achieved accurate results, but they require custom approaches for each object and laborious setup and training environments often stretching to extensive simulations, whilst lacking real-time computation. We propose a general-purpose approach of data acquisition for 6-DoF pose estimation tasks in X-ray systems, a novel and general purpose YOLOv5-6D pose architecture for accurate and fast object pose estimation and a complete method for surgical screw pose estimation under acquisition geometry consideration from a monocular cone-beam X-ray image. The proposed YOLOv5-6D pose model achieves competitive results on public benchmarks whilst being considerably faster at 42 FPS on GPU. In addition, the method generalizes across varying X-ray acquisition geometry and semantic image complexity to enable accurate pose estimation over different domains. Finally, the proposed approach is tested for bone-screw pose estimation for computer-aided guidance during spine surgeries. The model achieves a 92.41% by the 0.1·d ADD-S metric, demonstrating a promising approach for enhancing surgical precision and patient outcomes. The code for YOLOv5-6D is publicly available at https://github.com/cviviers/YOLOv5-6D-Pose.

Correlation between Ankle Imaging Findings and Self-Reported Outcomes: A Longitudinal Assessment in Patients with Tibiofibular Diastasis

Background and Objectives: This longitudinal study investigated the correlation between imaging findings and self-reported questionnaire outcomes in patients with tibiofibular diastasis, exploring the effects of surgical screw removal versus conservative treatment. This study was conducted at “Victor Babes” University of Medicine and Pharmacy in Timisoara between 2018 and 2023. Materials and Methods: The study involved 85 patients in the screw removal group and 44 in the conservative group, assessed at 2 and 6 months post-surgery, answering the SF-36, HADS, and WHOQOL questionnaires. Results: Significant differences were observed at 2 months post-surgery, with the screw removal group showing lower shear wave velocities in ankle dorsiflexion (8.9 ± 1.4) and anterior talofibular ligament (2.8 ± 0.9), indicating better mobility compared to the conservative group (ankle dorsiflexion: 10.1 ± 1.8, ATFL: 3.2 ± 1.1). Radiographically, lower tibiofibular overlap (8.1 ± 2.1) in the screw removal group suggested improved joint fixation quality. These physical improvements were mirrored in the quality-of-life assessments, where the screw removal group reported higher physical health scores on the SF-36 survey at 2 months, a trend that continued at 6 months. At 2 months, ankle dorsiflexion demonstrated a strong negative correlation with the SF-36 Physical score (r = −0.417) and WHOQOL Physical domain (r = −0.394), and a positive correlation with HADS Anxiety (r = 0.312). Similarly, ATFL and CFL velocities negatively correlated with the SF-36 Physical score (ATFL: r = −0.251; CFL: r = −0.237). Radiographic tibiofibular overlap and clear space positively correlated with WHOQOL Physical domain (TOL: r = 0.291; TCS: r = 0.276), with TCS also negatively correlating with HADS Anxiety (r = −0.228). At 6 months, these correlations persisted, with notable negative correlations between ultrasound ankle dorsiflexion and both SF-36 Physical score and WHOQOL Physical domain. Conclusions: These findings underscore the advantages of screw removal in enhancing physical recovery and reducing anxiety in the short term, while indicating similar long-term mental health outcomes between treatment approaches.

Ventriculoperitoneal shunt with the valve placed on the chest wall using a fixation technique that uses titanium screws for securing the reservoir to the cranium

BackgroundThe adjustable shunt valves of ventriculoperitoneal shunts (VPS) produce magnetic artifacts, which could disturb magnetic resonance imaging (MRI), and should therefore be placed on the chest wall. However, some significant complications, including ventricular catheter migration, disconnection, and rupture, should be considered. This study proposed a novel method for VPS placement with the valve placed on the chest wall using a fixation technique that uses titanium screws for securing the reservoir to the cranium. MethodsAfter a right-angled ventricular catheter with reservoir was inserted into the lateral ventricle, a 4-mm self-tapping titanium screw was inserted directly through the collars of the reservoir to fix it to the cranium. Adjustable shunt valves were implanted in the infraclavicular fossa of the chest wall. The connection site between the valve and tube was fastened using 3–0 nonabsorbable braided nylon surgical sutures. ResultsIn this study, following VPS placement in 83 patients with normal-pressure hydrocephalus, the review of all postprocedural images showed that of the 83 patients, four patients (4.8%) had catheter placement complications: two patients (2.4%) had incorrect placement of the ventricular catheter and two patients (2.4%) had subcutaneous migration of the abdominal catheter. None of the patients complained of ventricular catheter migration, disconnection, or rupture. ConclusionIn adult patients, placing the VPS valve in the chest and fixing the proximal catheter to the cranium using surgical screws can be an effective way to avoid MRI artifacts and to counteract mechanical failure due to the dislodgment of the proximal catheter.

How to use X-ray templating to guide minimally invasive screw removal.

A How to Do It article describing the use of X-ray templating to guide minimally invasive surgical screw removal. By calibrating X-ray measurements using the screw itself as a template marker, we propose a method to reduce incision size and operative time to minimise the risks associated with screw removal.

A novel technique to retrieve a cold welded gingival former- A Technical note

Cold welding is one of the mechanical complications of dental implants. This case report describes how a cold welded gingival former was successfully retrieved without damaging the threads using combination of ultrasonic scaler, surgical screw driver and a gingival retraction cord. This is a simple, cost-effective technique that can be adopted in all dental implant systems.

Pullout Strength of Triply Periodic Minimal Surface-Structured Bone Implants

Porous bone implants, such as triply periodic minimal surface structures (TPMS) bone implants, are thriving due to controllable physical properties, better osseointegration, and customized morphologies. However, the fixation of screws in such bone implants has yet to be discussed. Here, we investigated the insertion and pullout behavior of surgical screws in TPMS bone implants, including the Fisher Koch S and Gyroid solid-networks. We showed that the effective Young's modulus, insertion force, and pullout strength of the TPMS bone implants can be tuned by structural parameters. Our results revealed that the pullout strength is highly correlated with the maximum insertion force for both the TPMS and solid bone implants. Furthermore, the TPMS ones have significantly larger pullout strengths. We quantified the screw stability by the pullout strength to maximum insertion force ratio, which is 6.70±0.68 and 1.60±0.07 for the TPMS and solid bone implants, respectively. The significantly higher pullout strength of the TPMS bone implants results from the different bone failure mechanisms. Therefore, adopting TPMS architectures in bone implants can relieve the force required to place a surgical screw and enhance the screw stability.

Osteosynthesis Metal Plate System for Bone Fixation Using Bicortical Screws: Numerical-Experimental Characterization.

Simple SummaryThis study addresses an important issue concerning the evaluation of stresses in bone shafts stabilized by osteosynthesis metal plates, following routine surgical procedures to repair severe fractures in bone. It is recognized that bone regeneration following fracture is highly dictated by the stress state in the damaged regions. Since metallic inserts, like plates and screws, are usually employed to assure the stabilization of fractures in bone, it is important to evaluate the effect of those parts on the developed stresses in bone tissue. In the present work fracture was induced in a femoral bone of an animal model, which was suitably stabilized with a dynamic compression plate (DCP) using bicortical screws. This system was submitted to bending to trigger damage in bone tissue in the vicinity of metal inserts. Finite element modelling was then performed to mimic damage initiation and propagation in bone, thus simulating the results observed experimentally. Stress distributions in the vicinity of the screwed regions due to fastening of DCP allowed to identify very significant differences, which can affect bone hilling processes. It can be concluded that the developed procedure may be used to help surgeons to support decisions regarding bone repair using standard DCP.This study reports the numerical and experimental characterization of a standard immobilization system currently being used to treat simple oblique bone fractures of femoral diaphyses. The procedure focuses on the assessment of the mechanical behavior of a bone stabilized with a dynamic compression plate (DCP) in a neutralization function, associated to a lag screw, fastened with surgical screws. The non-linear behavior of cortical bone tissue was revealed through four-point bending tests, from which damage initiation and propagation occurred. Since screw loosening was visible during the loading process, damage parameters were measured experimentally in independent pull-out tests. A realistic numerical model of the DCP-femur setup was constructed, combining the evaluated damage parameters and contact pairs. A mixed-mode (I+II) trapezoidal damage law was employed to mimic the mechanical behavior of both the screw–bone interface and bone fractures. The numerical model replicated the global behavior observed experimentally, which was visible by the initial stiffness and the ability to preview the first loading peak, and bone crack satisfactorily.

Navicular Stress Fractures in Adolescent Athletes: Injury Characteristics and Outcomes of Surgical Fixation

Background: Surgical treatment of navicular stress fractures (NSF) in athletes has been recommended secondary to the poor blood supply of the navicular and frequency of delayed union and refracture. Regardless of treatment, nonunion and persistent pain are complications described in adults. The purpose of this study was to describe patient and fracture characteristics and outcomes of surgical treatment of NSF in adolescents. Methods: An IRB approved retrospective review was performed of patients less than 18 years of age treated with surgical screw fixation of NSF from 2014 – 2019. All patients were contacted for collection of patient reported outcome measures (PROMs). Results: Five patients with a median age of 15.8 years (range 14 – 17 years) were included. Three patients, all baseball catchers, had a dorsal navicular osteophyte. All fractures were in the lateral third of the navicular. There were 3 type 2 fractures and 2 type 3 fractures. Median clinical follow-up was 7.1 months (range 5 – 14 months). No patient developed avascular necrosis. PROMs at a median of 61 months following surgery demonstrated that all patients returned to their primary sport at the same level and no patients reported refracture or subsequent surgeries. Conclusions: In a cohort of adolescent patients, operative fixation of type 2 and 3 NSF results in reliable healing, no evidence for AVN, and excellent mid-term outcomes with full return to sports. These outcomes are in contrast to higher rates of non-union and inability to return to sports reported in the adult literature.

Accuracy of auto-identification of the posteroanterior cephalometric landmarks using cascade convolution neural network algorithm and cephalometric images of different quality from nationwide multiple centers

The purpose of this study was to evaluate the accuracy of auto-identification of the posteroanterior (PA) cephalometric landmarks using the cascade convolution neural network (CNN) algorithm and PA cephalogram images of a different quality from nationwide multiple centers nationwide. Of the 2798 PA cephalograms from 9 university hospitals, 2418 images (2075 training set and 343 validation set) were used to train the CNN algorithm for auto-identification of 16 PA cephalometric landmarks. Subsequently, 99 pretreatment images from the remaining 380 test set images were used to evaluate the accuracy of auto-identification of the CNN algorithm by comparing with the identification by a human examiner (gold standard) using V-Ceph 8.0 (Ostem, Seoul, South Korea). Pretreatment images were used to eliminate the effects of orthodontic bracket, tube and wire, surgical plate, and surgical screws. Paired t test was performed to compare the x- and y-coordinates of each landmark. The point-to-point error and the successful detection rate (range, within 2.0 mm) were calculated. The number of landmarks without a significant difference between the location identified by the human examiner and by auto-identification by the CNN algorithm were 8 on the x-coordinate and 5 on the y-coordinate, respectively. The mean point-to-point error was 1.52 mm. The low point-to-point error (<1.0 mm) was observed at the left and right antegonion (0.96 mm and 0.99 mm, respectively) and the high point-to-point error (>2.0 mm) was observed at the maxillary right first molar root apex (2.18 mm). The mean successful detection rate of auto-identification was 83.3%. Cascade CNN algorithm for auto-identification of PA cephalometric landmarks showed a possibility of an effective alternative to manual identification.

Failure Analysis of Austenitic Stainless Steel Implant Screws and Prospection of Chemical Composition Using Artificial Intelligence

In this work, austenitic stainless steel screws employed in a locking compression plate for veterinarian use were investigated. These types of implants are widely utilized in bone fractures healing. Two surgical screws were extracted due to the observation of slight superficial red rust colorizing on one of the screw implants, visual evidence of probable screw rusting. From the same implant, another screw was extracted simultaneously without visual evidence of rusting. In order to characterize and analyze the different behavior of both screws, the chemical composition was characterized by atomic absorption and energy dispersive X-ray spectroscopy (EDS) coupled to a scanning electron microscope (SEM). Also, the screws were studied by metallography, optical microscopy (OM), Vickers microhardness tests, and SEM analysis. On the other hand, a prospection for alloy chemical composition limits of these types of implants was performed based on the Schaeffler-Delong diagram and the ASTM F-138 standard. To analyze the effect of the chemical composition, heat treatment, microstructure, pitting resistance equivalent number (PRE) and stacking fault energy (SFE), a genetic algorithm (GA) and an artificial neural network (ANN) were used. In accordance with the elemental analysis, the surgical screws do not fulfill the ranges of the chemical composition established by the ASTM F-138 standard. Furthermore, there were found differences between the microstructures of the screws. In regard to the prospection, the results of GA and ANN support the proposed chemical composition region on the Schaeffler-Delong diagram. The corrosion failure was associated with severe plastic deformation and the presence of precipitates. The proposal can minimize the cause of failures in these types of austenitic stainless steel implants.

Surgical miniscrew assisted orthodontics; changes in facial appearance and smile of an adult female: A case study

Proclined upper incisors are the reasons for lip incompetence, excessive incisor display and very unesthetic smile characters for a good number of patients seeking orthodontic treatment. Majority of these cases are treated following extraction of premolars and intrusion and retraction of incisors, which became much more feasible through usage of temporary anchorage devices like miniscrew implants. Before titanium orthodontic miniscrew were available in the market, surgical screws for fixation of bone-plates were started to be used for orthodontic anchorage. This article presents a case to show how surgical miniscrews can be utilized to intrude and retract severely proclined upper incisors to bring upon noticeable improvement in facial appearance and smile.

Auxetic Structures for Tissue Engineering Scaffolds and Biomedical Devices

An auxetic structure utilizing a negative Poisson’s ratio, which can expand transversally when axially expanded under tensional force, has not yet been studied in the tissue engineering and biomedical area. However, the recent advent of new technologies, such as additive manufacturing or 3D printing, has showed prospective results aimed at producing three-dimensional structures. Auxetic structures are fabricated by additive manufacturing, soft lithography, machining technology, compressed foaming, and textile fabrication using various biomaterials, including poly(ethylene glycol diacrylate), polyurethane, poly(lactic-glycolic acid), chitosan, hydroxyapatite, and using a hard material such as a silicon wafer. After fabricating the scaffold with an auxetic effect, researchers have cultured fibroblasts, osteoblasts, chondrocytes, myoblasts, and various stem cells, including mesenchymal stem cells, bone marrow stem cells, and embryonic stem cells. Additionally, they have shown new possibilities as scaffolds through tissue engineering by cell proliferation, migration, alignment, differentiation, and target tissue regeneration. In addition, auxetic structures and their unique deformation characteristics have been explored in several biomedical devices, including implants, stents, and surgical screws. Although still in the early stages, the auxetic structure, which can create mechanical properties tailored to natural tissue by changing the internal architecture of the structure, is expected to show an improved tissue reconstruction ability. In addition, continuous research at the cellular level using the auxetic micro and nano-environment could provide a breakthrough for tissue reconstruction.

DESIGN OF SPECIALIZED SURGICAL SCREW INSERTED IN PLATE TYPE CERVICAL IMPLANT

In the field of Implantology the screws are an important part because they transfer the loads that occur in the bones. Surgical screws are similar to those in Mechanical Engineering, but the materials should have specific characteristics like biocompatibility, strength, corrosion resistance and fatigue strength. The main function of the surgical screw is to create pressure between two bones which is necessary in order to heal the injured bones. The surgical screw transforms all forces of the movements to pressure and distributes the pressure on the bone’s surfaces. Surgical screws can help in the setting of implants into an injured area. It also ensures static position of the injured bones. The research aims to analyse how the surgical screw type affects the bone of the patient with the help of the Finite Elements Method (FEM). Based on the results from the analysis of the surgical screw a new specialized surgical screw was designed with complex geometry to withstand the occurring loads and also be able to transfer them to the bone tissue. In additional, a comparison analysis between two different types of surgical screws was conducted. This paper shows how a surgical screw could be optimized in order to improve its function with the help of virtual tools. Finally, the materials used are biocompatible and often used for such screws and surgical implant analysis, the challenge was to recreate the bone tissue properties and to used them in the FEM analysis.

CUSTOMIZATION BASED ON CAD AUTOMATION IN PRODUCTION OF MEDICAL SCREWS BY 3D PRINTING

The paper presents a proposal of a complete CAD Automation solution enabling customization of the production of medical screws to individual patient requirements. The proposed approach using OLE technology enables the introduction of customization at the CAD project stage. The assembly of the surgical screw in the PLM system is generated by means of a specially developed application. The application communicates with the SolidEdge system using an API, taking into account 10 different input parameters. Three different types of medical screws have been developed in the application: the Herbert Screw, Cancellous Screw, and Malleolar Screw with three different thread types: rectangular, isosceles, and trapezoidal. The screws designed in this way can be manufactured using 3D printing techniques or CNC machining, and can be used for both humans and animals.

3D-Printing of Drug-Eluting Implants: An Overview of the Current Developments Described in the Literature.

The usage of 3D-printing for drug-eluting implants combines the advantages of a targeted local drug therapy over longer periods of time at the precise location of the disease with a manufacturing technique that easily allows modifications of the implant shape to comply with the individual needs of each patient. Research until now has been focused on several aspects of this topic such as 3D-printing with different materials or printing techniques to achieve implants with different shapes, mechanical properties or release profiles. This review is intended to provide an overview of the developments currently described in the literature. The topic is very multifaceted and several of the investigated aspects are not related to just one type of application. Consequently, this overview deals with the topic of 3D-printed drug-eluting implants in the application fields of stents and catheters, gynecological devices, devices for bone treatment and surgical screws, antitumoral devices and surgical meshes, as well as other devices with either simple or complex geometry. Overall, the current findings highlight the great potential of the manufacturing of drug-eluting implants via 3D-printing technology for advanced individualized medicine despite remaining challenges such as the regulatory approval of individualized implants.

Trans-isthmic pars interarticularis screw fixation under CT and fluoroscopic guidance: technical success and clinical outcome in patients with symptomatic low-grade lumbar isthmic lysis.

To assess the technical success of trans-isthmic screw fixation with simultaneous CT and fluoroscopic guidance in patients with symptomatic low-grade isthmic spondylolisthesis. Fifty patients (28 women and 22 men; mean age ± standard deviation: 50 years ± 18.9) presenting with symptomatic low back pain with isthmic spondylolisthesis refractory to medical management were treated by means of trans-isthmic pars interarticularis percutaneous screw fixation. The procedure was performed under local anesthesia with double CT and fluoroscopic guidance. Primary outcome was technical success of the procedure, which was assessed with a post-procedure CT using the same success criteria as surgical screw placement with regard to entry point, trajectory, and screw tip. Secondary outcome was pain decrease assessed by the Visual Analog Scale (VAS). Ninety-nine procedures were performed in 50 patients and 99 screws were inserted. Postoperative CT assessment showed satisfactory screw placement in 96 cases, reflecting a technical success rate of 96.9%. No complications occurred during or after the procedure. Pain assessment showed a pain decrease of VAS score from a median of 7 (min 5, max 10; MAD 1.4) to 2 (p < 0.0001) (min 0, max 7, MAD 1.7) with a mean follow-up of 39 months. Trans-isthmic screw fixation performed under CT and fluoroscopic guidance presents a high technical success and appears as a safe procedure and effective procedure in patients with symptomatic low-grade isthmic lysis. • Trans-isthmic pars interarticularis percutaneous screw insertion is feasible under double CT and fluoroscopic guidance by a radiologist with a high technical success. • This technique can be performed under local anesthesia only. • In patients with chronic low back pain, isthmic screwing allows long-term pain improvement.

Atraumatic Technique for Removal of Lingually Placed Mandibular Teeth

AbstractWe describe an innovative and easy method to remove lingually placed mandibular single-rooted teeth which are not accessible to regular forceps method of extraction. This method is simple and atraumatic and preserves the lingual alveolar plate which is important for implant placement and socket perseveration. This note is aimed at highlighting a simple atraumatic technique for removal of these types of single-rooted teeth erupting on the lingual side with the help of surgical screws. This technique is more economical and considerably less cumbersome than the existing Benex system.

Anatomical conditions and patient-specific locked navigation templates for transverse sacroiliac screw placement: a retrospective study

ObjectiveTo analyse the anatomical conditions of transverse sacroiliac screw (TSS) about the S1 and S2 segments in order to develop and validate a locked navigational template for TSS placement.MethodsA total of 22 patients with sacral fractures were involved in this study from May 2018 to February 2019. Patients were divided into two groups according to the surgery procedure: locked template group and conventional group. The CT data of 90 normal sacra were analysed. The long axis, short axis and lengths of TSS, cancellous corridors were measured through 3D modelling. A patient-specific locked navigation template based on simulated screws was designed and 3D printed and then used to assist in TSS placement. The operative time and radiation times were recorded. The Matta criteria and grading score were evaluated. The entry point deviation of the actual screw placement relative to the simulated screw placement was measured, and whether the whole screw was in the cancellous corridor was ob`served.ResultsS1 screws with a diameter of 7.3 mm could be inserted into 69 pelvises, and S2 screws could be inserted in all pelvises. The S1 cancellous corridor had a long axis of 25.44 ± 3.32 mm in males and 22.91 ± 2.46 mm in females, a short axis of 14.21 ± 2.19 mm in males and 12.15 ± 3.22 mm in females, a corridor length of 153.07 ± 11.99 mm in males and 151.11 ± 8.73 mm in females, and a proportional position of the optimal entry point in the long axis of the cancellous corridor of 35.96 ± 10.31% in males and 33.28 ± 7.2% in females. There were significant differences in the corridor long axis and corridor short axis between sexes (p < 0.05), and there were no significant differences in corridor length and proportional position of the optimal entry point in the long axis of the cancellous corridor between sexes (p > 0.05). The S2 cancellous corridor had a long axis of 17.58 ± 2.36 mm in males and 16 ± 2.64 mm in females, a short axis of 14.21 ± 2.19 mm in males and 13.14 ± 2.2 mm in females, a corridor length of 129.95 ± 0.89 mm in males and 136.5 ± 7.96 mm in females, and a proportional position of the optimal entry point in the long axis of the cancellous corridor of 46.77 ± 9.02% in males and 42.25 ± 11.95% in females. There were significant differences in the long axis, short axis and corridor length (p < 0.05). There was no significant difference in the proportional position of the optimal entry point in the long axis of the cancellous corridor (p > 0.05). A total of 20 transversal sacroiliac screws were successfully implanted into 10 patients with the assistance of locked navigation templates, and a total of 24 transversal sacroiliac screws were successfully implanted into 12 patients under C-arm fluoroscopy. There was a significant difference in surgical time (88 ± 14.76 min vs 102.5 ± 17.12 min, p = 0.048), radiation times (11.5 ± 1.78 vs 54.83 ± 6.59, p < 0.05) and screw grading between two groups (nineteen screws in grade 0, one screw in grade 1 and 0 screws in grade 2 vs fourteen screws in grade 0, 8 screws in grade 1 and 2 screws in grade 2, p = 0.005). All screw entry point deviations were shorter than the short axis of the cancellous corridor, and all screws were located completely within the cancellous corridor.ConclusionApproximately 76% of males and females can accommodate screws with diameters of 7.3 mm in S1, and all persons can accommodate the same screw in S2. From the standard lateral perspective of the sacrum, the optimal entry point of the transverse screw is in the first 1/3 of the cancellous corridor for S1 and the centre of the cancellous corridor for S2. The patient-specific locked navigation template assisted in TSS placement with less operative time, less intraoperative fluoroscopy and higher safety of screw placement compared with traditional surgery.