Sacroiliac Screw Research Articles

Cement augmentation in pelvic ring fractures

Cement augmentation of sacroiliac (SI) screws in the posterior pelvic ring has been shown to provide greater biomechanical stability in cadaveric studies. Pelvic ring fractures are relatively rare compared to the total number of fractures. Nevertheless, the 1‑year mortality rate of up to 27% is very high, especially for geriatric pelvic ring fractures and is also largely associated with reduced mobility due to the fracture. The primary goal of treatment is therefore the restoration of patient mobility. This requires the achievement of sufficient stability of the pelvic ring. As osteoporosis is often acausative factor for the pelvic ring fracture, amore stable anchoring of the implants in the osteoporotic bone can be achieved by cement augmentation. This article presents the possibilities of cement augmentation of the pelvic ring and describes the technique of cement-augmented SI screws.

A clinical and biomechanical comparison of INFIX plus single versus double sacroiliac screw fixation for unstable pelvic ring injury

BackgroundThe aim of this study is to compare the clinical and biomechanical outcome of INFIX plus single with two sacroiliac screw fixation for unstable pelvic fractures of Type C.MethodsSixteen cadavers were randomly subjected to INFIX plus single or double sacroiliac screw fixations and then mounted onto the ElectroForce loading machine under different vertical loads. To investigate the clinical outcomes of the two techniques, nineteen patients were retrospectively analyzed. The main outcome measures were postoperative radiographic reduction grading (using the Tornetta and Matta grading system), functional outcome (using the Majeed scoring system), and incidence of complications.ResultsIn the biomechanical study, INFIX plus double sacroiliac screw fixation showed better biomechanical stability than fixation with a single sacroiliac screw (p < 0.05). In our clinical case series, all 19 patients had bony union 6 months after the operation. INFIX plus double sacroiliac screw fixation also demonstrated a better functional outcome and a higher radiographic satisfactory rate than INFIX plus single sacroiliac screw fixation (79.25 ± 5.47; 91.33 ± 4.97; p < 0.05), (77.78% vs. 60%; p = 0.05). One patient in INFIX plus single-screw fixation group had screw loosening at 6-month follow-up postoperatively. One case in each group suffered heterotopic ossification and the lateral femoral cutaneous nerve paralysis, and one patient suffered from infection.ConclusionINFIX plus double sacroiliac screw fixation demonstrated more stability in cadaveric biomechanical analysis and better clinical outcomes than INFIX plus single sacroiliac screw fixation.

Sacro-pelvic Anthropometry in the Portuguese Population and Its Implication for Screw Placement in Spinal Surgery: A Single Centre Retrospective Analysis.

Objective The aim of this study was to assess the sacropelvic anthropometry in the Portuguese population, through the study of pelvic computed tomography (CT) scans. Methods Pelvic CT scans of 40 individuals were analyzed, and the length and angle measurements were performed according to predefined screw trajectories of S1 anterior (S1A), anterolateral (S1AL) and anteromedial (S1AM), S2 anterolateral (S2AL) and anteromedial (S2AM), S2 alar iliac (S2AI), iliac, and sacroiliac (SI) screws. Comparisons between genders were also performed. Results The S1A screw trajectory mean length was 30.80 mm. The S1AL mean length and lateral angle were 36.48 mm and 33.13°, respectively, and the S1AM's were 46.23 mm and 33.21°. The S2AL mean length was 28.66 mm and lateral angle was 26.52°, and the S2AM length and angle were 29.99 mm and 33.61°, respectively. The S2 alar-iliac screw trajectory mean length, lateral, and caudal angles were 125.84 mm, 36.78°, and 28.66°, respectively. The iliac screw trajectory mean length, lateral, and caudal angles were 136.73 mm, 23,86° and 24.01°, respectively. The sacroiliac screw trajectory length was 75.50 mm. The length of the screws was longer in men than in women, except for the S1A and SI screws, for which no difference was found between genders. Conclusion This study describes sacropelvic anatomical specifications. These defined morphometric details should be taken into consideration during surgical procedures.

Intraoperative assisted O-arm navigation imaging for unstable pelvic fractures in INFIX

To investigate the effect of internal external fixator assisted O-arm navigation imaging in the treatment of unstable pelvic fractures. From May 2019 to November 2019, 15 patients with unstable pelvic fractures were treated by intraoperative O-arm navigation imaging using INFIX technology. There were 6 males and 9 females. The age ranged from 24 to 66 years old. The course of disease ranged from 2 to 14 days. According to Tile classification, there were 1 case of B1 type, 8 cases of B2 type, 3 cases of C1 type, and 3 cases of C2 type. According to Young-Burgess classification, there were 8 cases of LC, 1 case of APC, 4 cases of VS, 2 cases of CM. Preoperative routine pelvic anteroposterior film, entrance position, exit position and pelvic CT three-dimensional reconstruction were performed. Intraoperative O-arm navigation system three-dimensional reconstruction and triplane scanning imaging were used to evaluate the effect of intraoperative reduction. The anterior pelvic ring was fixed with internal external fixator, and the posterior ring was fixed with sacroiliac screw, plate screw or lumbar iliac screw. The operation time, intraoperative bleeding and nail placement were observed and recorded. The quality of fracture reduction was evaluated by Matta standard, and the postoperative function was evaluated by Majeed function score. Wound healing was good in all patients without vascular, nerve and local irritation complications. All the 15 patients were followed up for 10 to 16 months. The fracture reduction was evaluated according to the Matta scoring standard, 9 cases were excellent results, 5 cases were good, and 1 case was medium. The Majeed functional score was 0 to 95 points. The built-in external fixator assisted O-arm navigation imaging system in the treatment of unstable pelvic fractures. The reduction effect is evaluated in advance, the operation time is shortened, and the accuracy of internal fixation is improved. The operation is simple, safe and less bleeding. The operation is in line with the principles of minimally invasive medical treatment and precision medical treatment in orthopedics, which is conducive to the recovery of patients' postoperative function and rapid recovery.

Biomechanical investigation of S2 alar-iliac screw and S1 pedicle screw fixation in the treatment of Denis type II sacral fractures.

Although S2 alar-iliac screw technique has been widely used in spinal surgery, its applicability to pelvic fractures is largely unknown. This study aimed to evaluate the biomechanical stability of S2 alar-iliac screw and S1 pedicle screw fixation in the treatment of Denis II sacral fractures. Twenty-eight artificial pelvic fracture models were treated with unilateral lumbopelvic fixation, sacroiliac screw fixation, S2 alar-iliac screw and S1 pedicle screw fixation, and S2 alar-iliac screw and contralateral S1 pedicle screw fixation (Groups 1-4, respectively; N = 7 per group). Each model was cyclically tested under increasing axial compression. Optical motion-tracking was used to assess relative displacement and gap angle, and the number of failure cycles. Relative displacement was significantly smaller in Group 3 than in Groups 1 (p = 0.004) and 4 (p < 0.001) but not significantly different between Groups 3 and 2 (p = 0.290). The gap angle in Group 3 was significantly smaller than that in Group 1 (p = 0.009) on the sagittal plane but significantly larger than that in Group 4 (p = 0.006) on the horizontal plane. A number of failure cycles was significantly higher in Group 3 than in Groups 1 (p = 0.002) and 4 (p = 0.004) but not significantly different between Groups 3 and 2 (p = 0.910). From a biomechanical perspective, S2 alar-iliac screw and S1 pedicle screw fixation can provide good stability in the treatment of Denis II sacral fractures.

Minimally invasive stabilization of fragility fractures of the pelvis with transsacral bar and retrograde transpubic screw

Stabilization of fragility fractures of the pelvis (FFP) using aminimally invasive technique. Insertion of atranssacral rod into the transsacral corridor of S1. Insertion of aretrograde transpubic screw through the superior branch of the pubic bone. Uni- or bilateral displaced fragility fractures of the sacrum or sacroiliac joint. Nondisplaced fractures of the sacrum or sacroiliac joint in case of nonsuccessful conservative treatment. Uni- or bilateral fractures of the superior branch of the pubic bone, which are present in combination with aposterior pelvic instability. Fragility fractures of the pelvis, which can be successfully treated conservatively. Absence of transsacral corridor in sacral body S1. Major displacement, nonreducible fractures of the superior branch of the pubic bone. Soft tissue infection at insertion site of implants. The transsacral bar is inserted under fluoroscopic control from ilium to ilium through the transsacral corridor of the sacral body S1. The retrograde transpubic screw is inserted from the pubic tubercle through the superior branch of the pubic bone past the acetabulum into the body of the ilium. An early mobilization with weight bearing of both lower extremities as tolerated by the patient is allowed. Conventional radiographs for control of the position of the implants and fractures are taken after mobilization RESULTS: In all, 64patients with FFP typeII, FFP typeIII or FFP typeIV were stabilized with atransacral bar osteosynthesis in the posterior pelvis. In 32patients (50%), additional sacroiliac screws were inserted. In 29patients (45.3%) the transsacral bar osteosynthesis was combined with atranspubic retrograde screw. Median length of hospital stay was 17.5days. In all, 20patients (31.3%) suffered general, 10patients (15.6%) suffered surgery-related complications, and 41patients (64.1%) were mobile in the room or on the ward at discharge. One-year mortality was 10.9%. The values of the SF‑8 Physical and Mental Component Scores, Parker Mobility Score and Numeric Rating Scale were moderate, yet comparable with the values of patients of the same age.

Pelvic ring injuries: classification and treatment

This review article will focus on the classification and treatment options for pelvic ring fractures. The pelvic ring can be split into anterior and posterior supporting structures. Injury can result in mechanical pelvic instability, the significance of which is determined by the magnitude and direction of forces applied during injury. The typical fracture patterns of anteroposterior compression, lateral compression and vertical shear form the basis of the Young and Burgess classification. However, the logic of the Tile classification system is useful in determining the degree of pelvic instability and the optimal surgical stabilization options. Posterior pelvic ring stabilization is often performed percutaneous after closed fracture reduction with sacro-iliac screws. This avoids the soft tissue complications often associated with open posterior approaches. Alternative reduction techniques can be performed through an open anterior approach using the first ilio-inguinal window to approach sacro-iliac joint disruptions as well as crescent fractures of the posterior iliac wing. The anterior pelvic ring, traditionally stabilized with external fixation, can be well accessed with the open ‘STOPPA’ approach. This allows access to an area extending from the pubic symphysis around the pelvic brim to the anterior aspect of the sacro-iliac joint where plates can be applied. Other options for anterior ring stabilization include column screws and the use of the ‘In-fix’ (Internal Fixator).

Differences in Accuracy and Radiation Dose in Placement of Iliosacral Screws: Comparison between 3D and 2D Fluoroscopy.

Percutaneous iliosacral screw fixation is a widely accepted method of stabilizing the posterior pelvic ring. Recently developed tools such as 3D-navigated fluoroscopy and computed navigation seem to prevent a surgeon from conducting screw misplacement. The study aimed to comparatively assess the introduction of sacroiliac screw placement using 2D and 3D fluoroscopy in terms of accuracy and radiation exposure. Iliosacral screws were introduced in 37 patients using 2D (group N1) and in 36 patients using 3D fluoroscopy (group N2) techniques. Overall, 61 and 56 screws were introduced in groups N1 and N2, respectively. Screw placement accuracy was assessed using postoperative computed tomography and Smith’s scale. Intraoperative radiation exposure was also assessed. No differences were noted between groups in terms of screw positioning accuracy and radiation dose. Both 2D and 3D fluoroscopy provide good visualization for safely placing percutaneous iliosacral joint screws. Using 3D fluoroscopy-based navigation in comparison with 2D fluoroscopy is not advantageous.

Three-dimensional digital anatomical measurement of modified sacroiliac screws

PurposeTo rebuild a model of the pelvis and effectively simulate the trajectory of modified sacroiliac screws, we measured the parameters of each screw and screw channel and assessed the safety and feasibility of the parameters in adults.Method and materialsOne hundred (50 males and 50 females) normal adult pelvic computed tomography (CT) images were randomly selected and imported into Mimics software to rebuild the three-dimensional pelvis model. In these models, each ideal channel of modified screws was simulated, and then we obtained the precise parameters of screws and channels using Mimics and Three-matic software.ResultsThe results of the comparison (right vs. left) showed that there were no significant differences in any of the angles, radius or M1SI parameters (the first modified sacroiliac). However, one parameter (BS) of M2SI (the second modified sacroiliac), two parameters (AP and BS) of M3SI (the third modified sacroiliac), and three parameters (AP, BS, L) of M4SI (the fourth modified sacroiliac) were statistically significant (P < 0.05). The result of comparison (between genders) showed that there were no significant differences in M1SI and M2SI; in contrast, the radius, length and the α angle of M3SI and M4SI were significantly different between genders (P < 0.05), and the radius of M4SI required special attention. If the radius of the limiting screw channel was > 3.50 mm, 52 cases (52%, 24 males and 28 females) could not complete the M4SI screw placement among 100 samples. If the radius of the limiting screw channel was > 3.0 mm, a total of 10 cases (10%, 2 males and 8 females) could not complete the M4SI screw placement.ConclusionThrough the measurement of 100 healthy adult real three-dimensional pelvic models, we obtained the parameters of each modified sacroiliac screw and measured the three angles of each screw based on international coordinates for the first time, which can instruct clinical application.

412 Operative Fixation for Acetabular Fractures in the Elderly: A Prospective Cohort Study from a UK Major Trauma Centre

Abstract Aim Due to an ageing population, acetabular fractures in the elderly is on the rise. Management of this group of patients remains controversial especially as it is associated with high morbidity and mortality. With an ageing population, there will be an increasing trend in low energy associated acetabular fractures. We present the largest cohort of operatively treated acetabular geriatric patients in the UK and compare different and emerging operative techniques and technology. Method A review of a prospective pelvic database was conducted. All patients over the age of 60 that had an operative fixation for an acetabular fracture from 2015 to 2020 were identified. Demographic data, operative data and complications were recorded. Length of stay and in-hospital mortality were also included. Results 109 patients were included in the study. The mean age was 73 and the mean Injury severity score was 13. The most common mechanism of injury was a fall from less than 1 meter (42%). The mean length of stay is 25 days. In-hospital mortality was 2% and 92% of patients had no in-hospital postoperative complication. A variety of metalwork was used ranging from sacroiliac screws to pelvic infix. Conclusions Advancements in orthopaedic implants have changed the management of geriatric acetabular fracture patients.

Starr frame-assisted minimally invasive internal fixation for pelvic fractures: Simultaneous anterior and posterior ring stability

ObjectiveWe aimed to investigate the surgical techniques, efficacy, and safety of Starr frame-assisted minimally invasive internal fixation for simultaneous anterior and posterior ring stability in pelvic fractures. MethodsThe clinical data of 22 patients with anterior and posterior pelvic ring injuries who underwent Starr frame-assisted minimally invasive internal fixation were retrospectively collected. The anterior pelvic ring was fixed with an anterior subcutaneous internal fixator (INFIX), and the posterior pelvic ring was fixed with sacroiliac screws. The operative time, intraoperative blood loss, fluoroscopy times, number of assistants, complications, and weight-bearing time were analyzed. The Matta score was used to evaluate the fracture reduction. The Majeed score was used to evaluate clinical efficacy, and Gibbon's classification was used to estimate the occurrence of sacral nerve injury. ResultsAll 22 patients were treated with sacroiliac screws for posterior ring injuries, including 12 cases with single sacroiliac screws, nine with two sacroiliac screws, and one with three sacroiliac screws. INFIX was used for all anterior ring fixation, including two screws in seven cases, three screws in 13 cases, and four screws in two cases. The fracture reduction quality was excellent in 15 cases, good in four cases, and moderate in three cases by Matta scores. All patients were followed up for 6–20 (12.5 ± 5.7) months. Callus-formation time based on postoperative X-ray was 3–8 (4.3 ± 1.2) weeks. Weight-bearing time was 3–12 (6.3 ± 2.8) weeks after surgery. At the last follow-up, 15 patients were evaluated as excellent, five as good, and two as fair according to the Majeed score. Gibbons’ classification showed that one of the three patients with sacral nerve injury recovered completely and two did not recover. Complications occurred in six patients, including one with internal fixation loosening, two with anterolateral thigh paresthesia, one with malunion, one with nonunion, and one with heterotopic ossification. ConclusionsStarr frame-assisted minimally invasive internal fixation could stabilize the anterior and posterior pelvic rings simultaneously, overcoming the difficulty of fracture reduction. This technique can help patients with early postoperative weight-bearing and improved functional outcomes, providing a novel modality for the minimally invasive treatment of pelvic ring injuries.

Clinical Analysis of Single and Double Sacroiliac Screws in the Treatment of Tile C1 Pelvic Fracture.

We investigated the difference between fixation of single and double sacroiliac screws in the treatment of Tile C1 pelvic fractures. The data of 54 patients with Tile C1 pelvic fractures who were admitted to the trauma center of the Red Society Hospital Affiliated to Xi'an Jiaotong University between August 2016 and August 2020 were retrospectively analyzed. All patients with posterior pelvic ring injuries underwent fixation with sacroiliac screws assisted by a percutaneous robotic navigation system. The operative time, amount of intraoperative blood loss, and postoperative follow-up time between the two groups (single sacroiliac and double sacroiliac screw groups) were compared. The Matta and Majeed scores at the last follow-up were compared between the groups to evaluate fracture reduction and functional recovery. Forty-nine patients were followed up for 17.2 (±4.5) months and 16.2 (±3.4) months in the single and double sacroiliac screw groups, respectively. All patients had excellent fracture reduction immediately after surgery, according to the Matta score. All fractures healed without complications. There was no statistically significant difference in preoperative general information, amount intraoperative blood loss, intraoperative anterior ring fixation method, and postoperative follow-up time between the two groups (P > 0.05). The operative time of the single sacroiliac screw group was shorter than that of the double sacroiliac screw group (P < 0.05). At the last follow-up, the Matta score of the double sacroiliac screw group was significantly better than that of the single sacroiliac screw group (P < 0.05), and there was no statistically significant difference in the Majeed functional scores (P > 0.05). For Tile C1 pelvic fractures, double sacroiliac screw fixation of posterior ring injuries can provide a more stable treatment with no statistically significant difference in functional recovery.

Can Partially Threaded Cannulated Screws Be Better Designed to Maximize Purchase in the Sacrum?

Sacroiliac screw fixation involves the use of cannulated, partially or fully threaded screws. Current partially threaded screws have standardized thread lengths involving a small portion of the screw regardless of its overall length. Forty uninjured computed tomography images were evaluated for distances from the lateral iliac cortex to the lateral sacral cortex at the first and second sacral segments. No difference in measurements were observed for gender, age, or body mass index. Using a smooth segment value of 32 mm, a significant increase in thread lengths is achievable allowing for a novel sacroiliac screw design to achieve greater purchase in the sacrum.

Percutaneous Sacroiliac Screw Fixation in a Pediatric with Unstable Bilateral Superior Rami and Sacral Fracture-Dislocation; a Case Report and Review of the Literature

Percutaneous Sacroiliac Screw Fixation in a Pediatric with Unstable Bilateral Superior Rami and Sacral Fracture-Dislocation; a Case Report and Review of the Literature

Tile Type C Pelvic Fractures: Initial Management, Surgery and Rehabilitation Results of 12 Cases with Literature Review

We report the results of 12 patients followed for Tile type C pelvic fractures treated with percutaneous sacroiliac screwing combined to anterior ring reduction and fixation provided by plate or external fixator during the last 4 years. this study was carried out in the light of literature review to focus on the therapeutic principles of the initial management, the different surgical techniques described for the definitive treatment of bone lesions, the current attitude regarding the rehabilitation of patients and the perspectives under development.

Sacroiliac screw versus locking square plate fixation in sacroiliac joint disruption on composite bone models: A descriptive comparative biomechanical study

BackgroundThe aim of this study was to compare a locking square plate to a standard sacroiliac (SI) screw of the sacroiliac joint on a composite pelvic bone model to assess the ultimate load tolerated before failure of fixation and describe the mode of failure of the construct. MethodsBilateral sacroiliac joint dislocations were created in 10 composite pelvic bone models. In this descriptive comparative study, the one SI joint was fixated using a 7.3 mm cannulated screw and the contralateral side using a 4-hole square locking plate. The pubic symphysis was not fixed. An upward vertical load was manually applied to each respective SI joint using a hook into the sciatic notch. The ultimate load to failure and the mode of failure was recorded for both groups. ResultsThe median load to failure for the SI screw group was 310 Newton (N) (range 280–390 N) and for the SI plate group 580 N (range 380–760 N). The ultimate load to failure was significantly lower in the SI screw group (p = 0.0002). No hardware-related failures were recorded in any of the fixations. The SI screw group had failure through a fracture of the sacrum in all the specimens. In the SI plate group, fractures of the sacrum and ilium constituted 60% and 40%, respectively. ConclusionA locking square plate fixation is superior to a single SI screw at the ultimate load to failure when a vertical load is applied to the sacroiliac joint in a composite bone model.

Does Cement Augmentation of the Sacroiliac Screw Lead to Superior Biomechanical Results for Fixation of the Posterior Pelvic Ring? A Biomechanical Study.

Background and Objectives: The stability of the pelvic ring mainly depends on the integrity of its posterior part. Percutaneous sacroiliac (SI) screws are widely implanted as standard of care treatment. The main risk factors for their fixation failure are related to vertical shear or transforaminal sacral fractures. The aim of this study was to compare the biomechanical performance of fixations using one (Group 1) or two (Group 2) standard SI screws versus one SI screw with bone cement augmentation (Group 3). Materials and Methods: Unstable fractures of the pelvic ring (AO/OTA 61-C1.3, FFP IIc) were simulated in 21 artificial pelvises by means of vertical osteotomies in the ipsilateral anterior and posterior pelvic ring. A supra-acetabular external fixator was applied to address the anterior fracture. All specimens were tested under progressively increasing cyclic loading until failure, with monitoring by means of motion tracking. Fracture site displacement and cycles to failure were evaluated. Results: Fracture displacement after 500 cycles was lowest in Group 3 (0.76 cm [0.30] (median [interquartile range, IQR])) followed by Group 1 (1.42 cm, [0.21]) and Group 2 (1.42 cm [1.66]), with significant differences between Groups 1 and 3, p = 0.04. Fracture displacement after 1000 cycles was significantly lower in Group 3 (1.15 cm [0.37]) compared to both Group 1 (2.19 cm [2.39]) and Group 2 (2.23 cm [3.65]), p ≤ 0.04. Cycles to failure (Group 1: 3930 ± 890 (mean ± standard deviation), Group 2: 3676 ± 348, Group 3: 3764 ± 645) did not differ significantly between the groups, p = 0.79. Conclusions: In our biomechanical setup cement augmentation of one SI screw resulted in significantly less displacement compared to the use of one or two SI screws. However, the number of cycles to failure was not significantly different between the groups. Cement augmentation of one SI screw seems to be a useful treatment option for posterior pelvic ring fixation, especially in osteoporotic bone.

Is cement-augmented sacroiliac screw fixation with partially threaded screws superior to that with fully threaded screws concerning compression and pull-out force in fragility fractures of the sacrum? \u2013 a biomechanical analysis

BackgroundProviding a stable osteosynthesis in fragility fractures of the pelvis can be challenging. Cement augmentation increases screw fixation in osteoporotic bone. Generating interfragmentary compression by using a lag screw also improves the stability. However, it is not known if interfragmentary compression can be achieved in osteoporotic sacral bone by cement augmentation of lag screws.The purpose of this study was to compare cement-augmented sacroiliac screw osteosynthesis using partially versus fully threaded screws in osteoporotic hemipelvises concerning compression of fracture gap and pull-out force.MethodsNine fresh-frozen human cadaveric pelvises with osteoporosis were used. In all specimens, one side was treated with an augmented fully threaded screw (group A), and the other side with an augmented partially threaded screw (group B) after generating a vertical osteotomy on both sides of each sacrum. Afterwards, first a compression test with fracture gap measurement after tightening of the screws was performed, followed by an axial pull-out test measuring the maximum pull-out force of the screws.ResultsThe fracture gap was significantly wider in group A (mean: 1.90 mm; SD: 1.64) than in group B (mean: 0.91 mm; SD: 1.03; p = 0.028).Pull-out force was higher in group A (mean: 1696 N; SD: 1452) than in group B (mean: 1616 N; SD: 824), but this difference was not statistically significant (p = 0.767).ConclusionsCement augmentation of partially threaded screws in sacroiliac screw fixation allows narrowing of the fracture gap even in osteoporotic bone, while resistance against pull-out force is not significantly lower in partially threaded screws compared to fully threaded screws.

Clinical application of anterior ring internal fixator system combined with sacroiliac screw fixation in Tile C pelvic fracture treatment

BackgroundHow to perform minimally invasive surgery for Tile C pelvic fracture is a major problem in clinical practice. We performed minimally invasive surgery for Tile C pelvic fracture using anterior ring internal fixator systems combined with sacroiliac screw fixation.ObjectiveTo investigate the advantages and efficacy of anterior ring internal fixator systems combined with sacroiliac screw fixation in the treatment of Tile C pelvic fracture.MethodsFrom May 2017 to May 2020, 27 patients with Tile C pelvic fracture who underwent anterior ring internal fixator system combined with sacroiliac screw fixation (group A) and 21 patients with Tile C pelvic fracture who underwent plate-screw system combined with sacroiliac screw fixation (group B) were retrospectively analyzed.ResultsAll 48 patients were followed up for more than 12 months, all fractures healed within 3–6 months. The operative time, intraoperative bleeding volume, blood transfusion volume, incision length, hospital stay, complication rate and Majeed score were 63.5 ± 10.7 min, 48.3 ± 27.9 ml, 0 ml, 4.5 ± 0.8 cm, 10.2 ± 2.7 d, 3.7% and 89.7 ± 4.6 points, respectively, in group A and 114.8 ± 19.1 min, 375 ± 315.8 ml, 266.7 ± 326.6 ml, 9.2 ± 3.9 cm, 20.9 ± 5.7 d, 23.8% and 88.7 ± 4.9 points, respectively, in group B. Combined excellent and good rates of the Matta evaluation and Majeed score were 100% in both groups. There were no significant differences in the Matta evaluation or Majeed score between the two groups (both P > 0.05), whereas the operative time, intraoperative bleeding volume, blood transfusion volume, incision length and hospital stay were significantly less in group A (all P < 0.05).ConclusionAn anterior ring internal fixator system combined with sacroiliac screw fixation can effectively treat Tile C pelvic fracture, and has advantages, including minimal invasiveness, simple operation, short operative time, safe and reliable features, fewer complications, short hospital stay and a good curative effect.

ANATOMICAL STUDY OF THE IDEAL POSITIONING OF THE S2 ILIAC SCREW

ABSTRACT Objective: To evaluate the morphometry of the pelvis to determine the safe trajectory for the insertion of the S2-iliac screw, and to correlate it with studies reported in the literature for other populations. Method: The computed tomography (CT) pelvic exams of 36 Brazilian patients without congenital malformations, tumors, pelvic ring fractures or dysplasias were selected from the database of a radiological clinic. To define the ideal trajectory of the S2-iliac screw, the following variables were measured: 1- maximum sacroiliac screw length; 2- thickness of the iliac dipole for planning the choice of screw dimensions (length and diameter); 3 - distance between the insertion point of the iliac S2 screw and the posterior sacral cortex; 4 - angulation for insertion of the screw in the mediolateral direction, representing the angle formed between the “iliac line” and the anatomical sagittal plane; 5- Angulation for insertion of the screw in the craniocaudal direction. The Pearson's chi squared and student's t tests were used for statistical analysis. Results: The sample consisted of 36 patients, 50% (18/36) of whom were women. The mean age was 63.7 years, ranging from 23 to 96 years. All the pelvic morphometric variables analyzed presented values similar to those described in the literature for other populations. Conclusion: Prior evaluation of the tomography exams was important for preoperative planning, and there was a statistically significant difference between the sexes only in relation to the variables left craniocaudal and length of the left internal table. Level of evidence III; Observational cross-sectional study.