Iliosacral Fixation Research Articles

Comparison of sacroiliac screw techniques for unstable sacroiliac joint disruptions: a finite element model analysis

Vertically unstable pelvic injuries associated with sacroiliac disruption are challenging. Although percutaneous iliosacral fixation using two screws at S1 vertebral body has been shown beneficial, the use of two transiliac screws at S1 has been proposed to increase the fixation strength of the construct. In the herein study, the finite element method (FEM) was performed to analyse the biomechanical behaviour of five different constructions using iliosacral screws only, transiliac screws only, and combining an iliosacral and a transiliac screw. A vertically unstable AO 61C1.2 type pelvic injury was produced for the evaluation of the posterior pelvic displacement and implant stress, and the anterior implant stress using FEM. The symphysis pubis was fixed with a 3.5-mm reconstruction plate in all cases. The model was axially loaded with 800N applied in the centre of S1 body, perpendicular to the ground (Y-axis), simulating the bipodal stance moment. There was a statistically significant reduction in both posterior displacement and implant stresses in the groups fixed with at least one transiliac screw compared to the groups fixed with iliosacral screws. In our FEM study, the construct using two transiliac screws in S1 is biomechanically superior for stabilizing the sacroiliac joint in vertically unstable pelvic ring injuries compared to the other configurations. Lateral displacement, posterior displacement, and von Mises stress were reduced with this construct. A good option can be the use of one iliosacral screw and one transiliac screw in S1.

Comparative study between open lumbopelvic fixation and percutaneous iliosacral fixation for management of sacral fractures

BackgroundThe main aim of surgical intervention for unstable sacral fractures is to obtain a solid construct across the lumbopelvic junction to allow for early mobilization. Both iliosacral screw fixation (ISF) and lumbopelvic fixation (LPF) are widely used surgical techniques used for treatment of unstable sacral fractures. Nevertheless, it is unclear whether one technique provides more favorable postoperative outcomes than the other.ObjectiveTo compare the three-year outcome of ISF versus LPF in patients with unstable sacral fractures as regard effectiveness and safety of both techniques.MethodsThe study included 54 patients with sacral fractures who underwent sacral fusion using either ISF or LPF at a single institution. Patients were followed up for at least 3 years. Operative and postoperative data were collected and statistically calculated.ResultsThirty patients were included in the ISF group and 24 patients in the LPF group. The operative time was notably higher in the LPF group (mean 107 min compared to 33 min in the ISF group; p = 0.002). Blood loss was also higher in the LPF group (mean 320 ml compared to 96 ml in the ISF; p = 0.004). Assessment of pelvic fusion was done via Majeed and Matta scores (pelvic fusion outcome scores). The ISF and LPF groups had a comparable Majeed score at the end of the third year of follow-up (excellent rate = 53.3% vs. 58.3%, respectively; p = 0.93). Likewise, ISF and LPF groups had comparable Matta score at the end of the third year of follow-up (excellent rate = 66.7% vs. 70.8%, respectively; p = 0.27). The most commonly reported postoperative complications in the ISF group were screw malposition in 2 cases out of 30 cases (6.6%) and non-union in 2 cases out of 30 cases (6.6%). On the other hand, the most commonly reported postoperative complications in the LPF group were implant prominence in 3 cases out of 24 cases (12.5%) and infection in 2 cases out of 24 cases (8.3%).ConclusionLPF and ISF have comparable safety and efficacy in patients with sacral fractures. ISF is an excellent and safe method of fixation, especially in old age to avoid open surgery-related complications. LPF is preferred in young active patients to benefit from rapid weight bearing after surgery and in cases with ambiguous sacral anatomy as sacral dysmorphism.

Beyond type III Paprosky acetabular defects: are partial pelvic replacements with iliosacral fixation successful?

Supra-acetabular bone loss close beyond the sciatic notch is one of the most challenging defect types for stable anatomical reconstruction in revision arthroplasty. Using reconstruction strategies from tumour orthopaedic surgery, we adapted tricortical trans-iliosacral fixation options for custom-made implants in revision arthroplasty. The aim of the present study was to present the clinical and radiological results of this extraordinary pelvic defect reconstruction. Between 2016 and 2021, 10 patients with a custom-made pelvic construct using tricortical iliosacral fixation (see Fig.1) were included in the study. Follow-up was 34 (SD 10; range 15-49) months. Postoperatively CT scans evaluating the implant position were performed. Functional outcome and the clinical results were recorded. Implantation was possible as planned in all cases in 236 (SD 64: range 170-378) min. Correct centre of rotation (COR) reconstruction was possible in nine cases. One sacrum screw crossed a neuroforamen in one case without clinical symptoms. During the follow-up period, four further operations were required in two patients. There were no individual implant revisions or aseptic loosening recorded. The Harris Hip Score increased significantly from 27 Pts. to 67 Pts. with a mean improvement of 37 (p < 0.005). EQ-5D developed from 0.562 to 0.725 (p = 0.038) as a clear improvement in quality of life. Custom-made partial pelvis replacement with iliosacral fixation offers a safe solution in "beyond Paprosky type III defects" for hip revision arthroplasty. Due to meticulous planning, precise implantation with good clinical outcome can be achieved. Furthermore, the functional outcome and patient satisfaction increased significantly showing promising early results with a relatively low complication rate.

RADIOLOGICAL CLASSIFICATION OF THE PELVIS: A TOOL FOR TRAUMA SURGICAL PLANNING

Dysmorphic pelves are a known risk factor for malpositioned iliosacral screws. Improved understanding of pelvic morphology will minimise the risk of screw misplacement, neurovascular injuries and failed fixation. Existing classifications for sacral anatomy are complex and impractical for clinical use. We propose a CT-based classification using variations in pelvic anatomy to predict the availability of transosseous corridors across the sacrum. The classification aims to refine surgical planning which may reduce the risk of surgical complications.The authors postulated 4 types of pelves. The “superior most point of the sacroiliac joint” (sSIJ) typically corresponds with the mid-lower half of the L5 vertebral body. Hence, “the anterior cortex of L5” (L5a) was divided to reference 3 distinct pelvic groups. A 4th group is required to represent pelves with a lumbosacral transitional vertebra. The proposed classification:A – sSIJ is above the midpoint of L5aB – sSIJ is between the midpoint and the lowest point of L5aC – sSIJ is below the lowest point of L5aD – pelves with a lumbosacral transitional vertebraSpecific measures such as the width of the S1 and S2 axial and coronal corridors and the S1 lateral mass angles were used to differentiate between pelvic types.Three-hundred pelvic CT scans were classified into their respective types. Analysis of the specific measures mentioned above illustrated the significant difference between each pelvic type. Changes in the size of S1 and S2 axial corridors formed a pattern that was unique for each pelvic type. The intra- and inter-observer ratings were 0.97 and 0.95 respectively.Distinct relationships between the sizes of S1 and S2 axial corridors informed our recommendations on trans-sacral or iliosacral fixation, number and orientation of screws for each pelvic type. This classification utilises variations in the posterior pelvic ring to offer a planning guide for the insertion of iliosacral screws.

Результат успешного лечения пациентки с сочетанной травмой, включающей оскольчатый переломовывих крестца, осложненный каудопатией

Introduction Combined injury, as a cause of death, occupies a central place in different age groups and is common for individuals ages 50 and younger. Most sacral fractures are traditionally repaired with screw or plate. However, the fixation can be unreliable in atypical anatomy of the upper sacral segment, U-shaped and H-shaped fractures, compression of nerve structures and failed fixation. Material and methods Reported is a case of a 29-year-old patient who suffered a severe concomitant injury including comminuted fracture-dislocation of the sacrum complicated by caudopathy. Results A good clinical and anatomical result was obtained. She developed a complete regression of neurological symptoms. The patient could ambulate without additional support. The function of the pelvic organs was restored. Discussion For a comparison, two methods were presented: lumbopelvic fixation using two rods and a transverse buckle and triangular fixation with a rod and an additional iliosacral screw. Lumbopelvic fixation is a surgical procedure for unstable pelvic ring injuries that allows immediate weight-bearing. Biomechanical tests showed greater primary stability with triangular lumbopelvic fixation than iliosacral fixation with no stress to the injured area. Bilateral lumbopelvic fixation with a transverse buckle allowed secure fixation of the lumbopelvic junction for fracture healing, protection of the sacroiliac joints preventing the development of transitional kyphosis and maintaining the spine balance with careful surgical handling of the soft tissues.

Minimally invasive triangular lumboiliac and iliosacral fixation of posterior pelvic ring injuries with vertical instability: Technical note

To date, no strong consensus exists on the best way to treat posterior pelvic ring injuries when there is no neurological deficit. Various fixation methods have been described; more recently, constructs that combine lumboiliac and iliosacral fixation have been introduced. This type of fixation is mainly indicated in cases of spinopelvic dissociation with large displacement of fracture fragments in the sagittal plane. However, these techniques are associated with postoperative complications, particularly infections and severe skin complications. This led us to propose a minimally invasive lumboiliac and iliosacral fixation technique for posterior pelvic ring injuries. The procedure is done with the patient prone. It consists of pedicle screw insertion into L4 or L5 and screw fixation of the ilium with fluoroscopy guidance; intraoperative distraction can be done depending on the amount of displacement. An iliosacral screw is then inserted percutaneously to allow reduction in the transverse plane and yield a triangular construct. In the five patients that we have operated using this technique, the mean preoperative vertical displacement was 11.9±6.9mm (SD) (min 1.3, max 19.7) versus 3.7±3.2mm (min 0.3, max 6.7) postoperatively and the mean preoperative frontal displacement was 7.5±3.7mm (min 4.2, max 12.4) versus 2.5±2.0mm (min 0.3, max 4.3) postoperatively. Minimally invasive iliosacral and lumboiliac fixation is an option for treating posterior pelvic ring fractures free of neurological deficit and especially spinopelvic dissociation.

Corridor-diameter-dependent angular tolerance for safe transiliosacral screw placement: an anatomic study of 433 pelves

The purpose of this study was to determine the angular tolerance of the S1 and S2 segments to accommodate a transiliosacral screw across both sacroiliac joints. We hypothesized that the angular tolerance for transiliosacral screw placement would be more constrained than the angular tolerance for iliosacral fixation in pelves where a safe osseous corridor was measured. The cortical boundaries of the S1 and S2 sacral segments in 433 pelvic CTs were digitally mapped. A straight-line path was placed within each osseous corridor and extended across both SI joints past the outer iliac cortices. The diameter of the path was increased until it breached the cortex, geometrically determining maximum diameter (Dmax). Angular tolerance for screw placement was calculated with trigonometric analysis of the Dmax value of the corridor, and the average distance from the termination of the osseous corridor to the site of percutaneous insertion. Gender, age, and BMI were evaluated as independent predictors using binomial logistic regression. The transiliosacral angular tolerance for the S1 and S2 osseous corridors was 1.53 ± 0.57 degrees and 1.02 ± 0.33 degrees, respectively. 68.9% of S1 corridors and 81.1% of S2 corridors had a safe zone (corridor diameter ≥ 10mm) for transiliosacral placement, 48.3% of the pelves had a safe zone for both corridors, while 5.1% had no safe zones. Females had a less frequent Dmax ≥ 10mm at S1, 52% vs 67% (p = 0.001), and at S2, 64% vs 86% (p < 0.001). In conclusion, the angular tolerance of 1.53 and 1.03 degrees for the S1 and S2 segments, respectively, creating a narrow interval for safe passage of the trans-iliac and trans-sacral, with approximately 31.1% of patients not having a viable corridor for screw passage. A correlation exist between S1 and S2 corridors with Dmax ≥ 10mm and the resulting increase in angular tolerance for safe passage of a transilioscral screw. Level Retrospective Cohort.

Determination of Anatomical Sacral Dysmorphism Criteria based on CT scan Findings for Iliosacral Screw Fixation in a Sample of Iranian Population without Pelvic Ring Fracture

Background: The pelvic ring, sacral fractures and sacroiliac dislocations are managed with different methods. The preferred treatment in sacral fractures or SIjoint dislocations is iliosacral screw fixation. The upper sacral segment dysplasia increases the risk of perforation of the osseous cortex during Iliosacral fixation with a screw. The dysmorphic sacra have a narrow and angular osseous corridor. Objectives: To date, no study has been conducted on the sacral dysmorphism and quantitative and qualitative criteria for fixation with iliosacral screw in sacral dysmorphism among the Iranian population. Methods: We analyzed 100 CT scan and Outlet CT reformation forms of traumatic patients without pelvic trauma to determine 5 qualitative criteria of sacral dysmorphism (i.e., mammillary bodies, misshapen sacral foramen, upper sacral segment not recessed in the pelvis, residual disc between S1 and S2 vertebra and acute alar slope). Upper sacral surface area and angulation were determined based on the CT scan reformatted. Results: Five qualitative criteria from the 3D pelvic CT outlet view and sixth characteristic (tongue-in-groove) from the axial pelvic CT section were obtained by an orthopedic surgeon. Coronal reconstruction was used to divide the patients into dysmorphic and non-dysmorphic groups by drawing a line along the axis of the osseous corridor from one side of iliosacral to its other side. The results showed that 37% of the patients were in the dysmorphic group and 63% in non-dysmorphic. Qualitative criteria were in the range 24% -71% in the dysmorphic group and 14%-34% in the non-dysmorphic group. The sacral dysmorphism score was calculated in all patients. The sacral dysmorphism score = (first sacral segment coronal angle) + 2(first sacral segment axial angle). The obtained mean angle in the dysmorphic and non-dysmorphic group was 84° and 72°, respectively. As the score increased, the safety of the osseous corridor decreased. The dysmorphic score ranged between 70 and 84 in one-third of the patients and none of them was less than 70°. Conclusion: In this study, sacral dysmorphism was detected in 37% of the patients. Axial angulation and coronal angulation were the most important quantitative criteria for determining the sacral dysmorphism. Detecting sacral dysmorphism can be useful for preoperative planning of iliosacral screw placement.

Efficacy and Safety of Minimally Invasive Percutaneous Ilio-Sacral Fixation Technique for Sacral Fractures in The Initial Twenty Cases at Department of Neurosurgery in Alexandria University

Background Data: Sacral fractures constitute a major entity of pelvic fractures. 50% of these sacral fractures are not recognized on initial physical examination of the traumatized patients. The most important prognostic factor in management of sacral fractures is the presence or absence of neurological deficit. Some studies adopt the concern regarding fixation of sacral fractures in poly-traumatized patients to avoid systemic effects and complications of recumbency. Purpose: Evaluation of the efficacy and safety of the minimally invasive percutaneous ilio-sacral fixation technique in management of initial twenty cases of sacral fractures at department of Neurosurgery in Alexandria University. Study Design: Retrospective clinical case cohort study. Patients and Methods: Between March 2017 and January 2019; 20 patients were presented at Neurosurgery Department in Alexandria University hospitals with traumatic sacral fractures. They were 13 males and 7 females with the mean of 34 years (ranged from 18-55 years). Plain X ray of pelvis including antero-posterior, inlet and outlet views of pelvis, CT scan with 3D reconstructions were done. We used Dennis classification and Roy-Camille classification in our study. Stabilization of sacral fracture was done percutaneously using 7 mm cannulated partially threaded ilio-sacral screws. Clinical, neurologic and radiographic examinations were performed in the follow up period (6 months) to assess healing, evaluate clinical improvement and to detect any implant changes. Results: Total 39 percutaneous ilio-sacral screws were placed in 20 patients. Partially threaded cancellous 7.0-millimeter cannulated screws were used. Fifteen patients had unilateral double screws; one patient had unilateral triple screws; two patients had bilateral single screws for bilateral sacral fracture and two patients had unilateral single screw. Two Misplaced screws out of thirty-nine screws were found in the post-operative CT. One patient developed post-operative foot drop. All fractures healed clinically and radio-graphically except one case fixed by single screw and did not show radiological healing. Conclusion: Percutaneous ilio-sacral fixation for sacral fractures is a safe minimally invasive method for management of sacral fractures. It is effective regarding pain relief with high fusion rate. It needs a long learning curve. Single screw fixation is not a rigid fixation and may lead to hardware failure. (2019ESJ193)

Traumatic Sacral Fractures: Navigation Technique in Instrumented Stabilization

Sacral fractures are a challenge regarding treatment and classification. Surgical techniques using spinal navigation systems can improve treatment, especially if used in collaboration among different specialists. Between 2015 and 2017, we treated 25 consecutive cases of sacral fracture. Twelve patients (48%) underwent mechanical ventilation due to hypovolemic shock for severe thoracoabdominal trauma; bleeding was blocked with pelvic packing in 9 cases (36%) and transcatheter embolization in 2 cases (8%). External fixation was used in 7 cases (28%). In 20 cases (80%) spinal fractures were associated. All patients were operated on using spinal navigation by a team of neurosurgeons and orthopedic surgeons. The mean time from first observation to surgery was 18 days (range 8-31). Surgical treatment consisted of iliosacral fixation in 19 cases (76%) and spinopelvic fixation in 6 cases (24%). The mean number of screws for spinopelvic fixation was 9.67 (range 6-17) with a mean operation time of 323.67 minutes (range 247-471); in iliosacral osteosynthesis the mean screw number was 1.37 (range 1-3) and mean surgical time was 78.93 minutes (range 61-130). Postoperative computed tomography showed the correct screw placement. Wound infection occurred in 2 cases (8%), managed with vacuum-assisted closure therapy; in 1 case (4%) a sacral screw was removed for decubitus. Navigation systems in instrumented spinopelvic and sacropelvic reconstruction provide greater safety, reducing learning times and malpositioning. Multidisciplinary management allows us to achieve optimal results, especially when the sacral fracture is combined with spinal and pelvic lesions. The use of navigation systems could represent an important advancement.

Iliosacral Screw Fixation in Patients with Polytrauma

The need to perform iliosacral fixation in patients with polytrauma and unstable pelvic injuries in the acute period of injury is still an unresolved issue. Minimally invasive techniques of pelvis internal fixation allow to perform single step reconstructive surgery in the acute period of the trauma.Purpose — to evaluate the results of minimally invasive acute iliosacral fixation in patients with polytrauma and unstable pelvic injuries.Materials and methods. The authors analyzed treatment outcomes in 105 patients with polytrauma and unstable pelvic injuries after iliosacral screw fixation in acute period. 69 (65.7%) patients had B-type and 36 (34.3%) patients had c-type of unstable pelvic injuries by AO/ASIF classification. Mean age was 35.5±11.7 years. The severity of injury on the ISS scale was 22.5±12.9 points. Ап patients underwent minimally invasive iliosacral fixation with screws in the acute period of the trauma.Results. Patients classified according to the severity of their status as «stable» (n = 50) and «borderline» (n = 26) with stable hemodynamics (SAD 90 mm Hg) underwent minimally invasive iliosacral screw fixation of posterior pelvic ring straight in the anti-shock surgery. Injured classified as «unstable» (n = 15) and «borderline» (n = 14) with unstable hemodynamic parameters (SAD 90 mm Hg), who needed urgent large surgical procedures (laparotomy, thoracotomy et al.), underwent temporary pelvis stabilization by external fixation and/or c-frame, and as the hemodynamic parameters were stabilized iliosacral screw fixation within 48 hours from the moment of injury. The functional pelvis state in 58 patients by S.A. Majeed scale rated 90.7±11.2 points. The quality of life was assessed using the SF-36 questionnaire.Conclusion. Restoration of the anatomical shape of the pelvic ring and its fixation, primarily posterior aspects, in the acute period of trauma allowed to obtain good anatomical and functional treatment outcomes in 94.9% of the patients with polytrauma.

Does Posterior Fixation of Partially Unstable Open-Book Pelvic Ring Injuries Decrease Symphyseal Plate Failure? A Biomechanical Study.

Recent clinical study suggests an advantage to adding an iliosacral screw to the anterior fixation construct for anteroposterior compression type-2 (OTA/AO type 61-B1), partially unstable open-book pelvic ring injuries. Others have described stress examination to determine any required supplemental fixation. However, biomechanical studies investigating iliosacral fixation requirements for this injury are lacking. Our objective was to determine whether adding an iliosacral screw to symphyseal plate fixation decreases displacement in a well-defined open-book pelvic ring injury model. An open-book pelvic ring injury was created in 10 human cadaveric pelves by unilaterally releasing the sacrospinous, sacrotuberous, and anterior sacroiliac ligaments plus transection of the pubic symphysis, approximating the classically described anteroposterior compression type-2 (APC-2) injury. Specimens were divided into 2 groups: (1) symphyseal plating and (2) plating plus an iliosacral screw. Using a standard bilateral stance model loaded at 550 N, displacement measurements were obtained at 210,000 and 500,000 cycles. Three specimens failed before 210,000 cycles because of technical errors and were excluded from analysis. For the remaining 7, there was no significant difference in displacement between the 2 groups, and none sustained implant failure. Post hoc analysis showed that a large sample size (45/group) would be required to detect any difference with 80% power, indicating a small effect size with limited clinical application. Adding an iliosacral screw to the symphyseal plate fixation does not provide improved biomechanical outcome in classically described APC-2 injuries. Clinically, stress examination may be useful to determine the need for supplemental posterior fixation in APC-2 injuries.

Evaluation of closed multi-axial screws iliosacral fixation system combined with posterior segmental spinal fixation for treatment of unstable sacral fractures

To evaluate the effectiveness of lumbopelvic fixation using the combination of closed multi-axial screws (CMAS) iliosacral fixation system and the posterior segmental spinal fixation for unstable sacral fractures. Between January 2013 and November 2014, 25 patients (39 sides) with unstable sacral fractures were treated with lumbopelvic fixation using the combination of CMAS iliosacral fixation system and the posterior segmental spinal fixation. There were 17 males and 8 females, aged 19-55 years (mean, 33.9 years). The causes were traffic accident injury in 15 cases, falling injury from height in 8 cases, and crushing injury in 2 cases. The interval of injury and operation was 1-13 days (mean, 3.5 days). Fracture was classified as Denis type I in 2 sides, type II in 20 sides, and type III in 17 sides; nerve injury was rated as Gibbons grade I in 2 cases, grade II in 2 cases, grade III in 7 cases, and grade IV in 9 cases. The reduction quality was evaluated by Matta criterion, the clinical function outcome by Majeed, and nerve function by Gibbons criterion. The average operation time was 110 minutes (range, 80-150 minutes). The average blood loss was 570 mL (range, 250-1 400 mL). Superficial wound infection occurred in 2 patients, and was cured after debridement and antibiotic therapy. All patients were followed up for an average of 18 months (range, 15-22 months). Postoperative X-ray and CT examination showed clinical healing of sacral fractures at 8-12 weeks after operation (mean, 10 weeks). The mean removal time of internal fixation was 13 months (range, 12-20 months). No screw loosening and fracture, adhesion of internal fixation to surrounding tissue, and obvious electrolysis phenomenon occurred. According to Matta criterion, reduction was rated as excellent in 32 sides, good in 6 sides, fair in 1 side, and the excellent and good rate was 97.5%. According to Majeed functional scoring at last follow-up, the mean score was 84.7 (range, 64-98); the results were excellent in 18 cases, good in 5 cases, and fair in 2 cases, and the excellent and good rate was 92.0%. The nerve function was significantly improved when compared with preoperative one; nerve injury was rated as Gibbons grade I in 8 cases, grade II in 8 cases, grade III in 3 cases, and grade IV in 1 case. Lumbopelvic fixation using the combination of CMAS iliosacral fixation system and the posterior segmental spinal fixation is a relatively effective fixation for unstable sacral fractures. Not only is the fracture fixation rigid for early full weight-bearing, but also nerve decompression can be performed which facilitates nerve function recovery.

Ilio-Sacral (IS) Screw Fixation for Sacral and Sacroiliac Joint (SIJ) Injuries in Children.

Treatment of sacral fractures and sacroiliac joint (SIJ) disruption with percutaneous ilio-sacral (IS) screw fixation had become a more popular treatment option. There has been no study that specifically assessed IS fixation in children. The purpose of this study is present our results with fixation of the sacral fractures and SIJ disruption using IS screw in children 18 years old and younger. This is a retrospective review chart for children with sacral fracture or SIJ disruption who were treated by IS fixation in the period from 2000 to 2012. The patients were assessed for the following (age, sex, type of injury, associated injuries, surgery, complications, postoperative return of function, healing of the injury, and return to function). In the studied period (2000 to 2012), 11 patients who had either sacral fracture (4 patients) or SIJ (7 patients) disruption were treated by IS screws. The average age of these patients was 14 years (range, 6 to 17 y). Six patients had 1 screw and 5 patients had 2 screws. Eight patients had their entire fixation in S1, and 3 patients had 1 screw in S1 and 1 screw in S2. All screws were cannulated and were inserted over a guidewire with fluoroscopy and/or navigation guidance. Five patients had added anterior fixation of the pelvis. One patient was lost for follow-up. All patients (except 1) achieved healing of their injuries with no displacement or implant failure with return of function. One patient had failure of fixation and needed revision. One patient had neurological complication related to screw insertion. IS screws can be safely used to treat sacral fractures and SIJ injuries in children. This was feasible in children as young as 6 years old. The complications of the procedure were minimal with good stability obtained by IS screws.

When do anterior external or internal fixators provide additional stability in an unstable (Tile C) pelvic fracture? A biomechanical study

This study aimed at evaluating the additional stability that is provided by anterior external and internal fixators in an unstable pelvic fracture model (OTA 61-C). An unstable pelvic fracture (OTA 61-C) was created in 27 synthetic pelves by making a 5-mm gap through the sacral foramina (posterior injury) and an ipsilateral pubic rami fracture (anterior injury). The posterior injury was fixed with either a single iliosacral (IS) screw, a single trans-iliac, trans-sacral (TS) screw, or two iliosacral screws (S1S2). Two anterior fixation techniques were utilized: external fixation (Ex-Fix) and supra-acetabular external fixation and internal fixation (In-Fix); supra-acetabular pedicle screws connected with a single subcutaneous spinal rod. The specimens were tested using a nondestructive single-leg stance model. Peak-to-peak (P2P) displacement and rotation and conditioning displacement (CD) were calculated. The Ex-Fix group failed in 83.3 % of specimens with concomitant single-level posterior fixation (Total: 15/18-7 of 9 IS fixation, 8 of 9 TS fixation), and 0 % (0/9) of specimens with concomitant two-level (S1S2) posterior fixation. All specimens with the In-Fix survived testing except for two specimens treated with In-Fix combined with IS fixation. Trans-sacral fixation had higher pubic rotation and greater sacral and pubic displacement than S1S2 (p < 0.05). Rotation of the pubis and sacrum was not different between In-Fix constructs combined with single-level IS and TS fixation. In this model of an unstable pelvic fracture (OTA 61-C), anterior fixation with an In-Fix was biomechanically superior to an anterior Ex-Fix in the setting of single-level posterior fixation. There was no biomechanical difference between the In-Fix and Ex-Fix when each was combined with two levels of posterior sacral fixation.

Usefulness of intraoperative three-dimensional imaging in fracture surgery: a prospective study

BackgroundSince its introduction, intraoperative threedimensional (3D) imaging has enabled the analysis of articular fractures and implant positions during fracture surgery. The purpose of this study was to evaluate the usefulness of intraoperative 3D imaging in locating anatomic structures, correcting errors, and preventing revision surgery. MethodsBetween March 2010 and November 2012, intraoperative 3D imaging was used during surgery for 109 fractures in 101 patients. Fluoroscopy was performed with the Iso-C3D™ (Siemens, Erlangen, Germany). We recorded the number of intraoperative revisions for adjustment of fracture reduction and correction of implant position for these fractures. ResultsCases comprised intra-articular fractures (55 %), disruptions of the posterior pelvic ring (33 %), and syndesmotic injury (12 %). The intraoperative revision rate was 9.2 % (10/109). When considered by fracture site, the revision rate was highest for syndesmotic injury (23.1 %), followed by iliosacral fixation (8.3 %) and intra-articular fractures (6.6 %). We changed the implant position in six cases, corrected the articular reduction in one case, and revised the malreduction of syndesmosis in three cases. No postoperative infection occurred in any of these cases. ConclusionsIntraoperative 3D imaging is useful for correcting errors and may prevent a second operation. Three-dimensional imaging may be especially helpful in intra-articular fractures, iliosacral screw fixation, and syndesmotic injury.

Internal fixation of bilateral sacroiliac dislocation with transiliac locked plate: a biomechanical study on pelvic models

The purpose of this study was to analyze and compare the mechanical characteristics of a new iliosacral fixation technique (bilateral S1 pedicle fixation through a transiliac locked plate) for bilateral sacroiliac dislocations with other previously described methods. Bilateral sacroiliac dislocations were created in 21 pelvic models and divided into three different fixation method groups. Group 1 was fixed using posterior tension band plating with a 3.5 mm locked plate combined with fixed-angle locked 3.5 mm screw fixation of bilateral S1 vertebra pedicles through suitable holes of the plate. Group 2 underwent posterior tension band plating with a 3.5 mm locked plate combined with bilateral spongious iliosacral screw fixation and Group 3 bilateral iliosacral spongious screw fixation alone. The ultimate load to failure and load for 10 mm of displacement for all three groups were compared. The average loads to failure for Groups 1, 2 and 3 were 1775, 2084 and 2230 N, respectively, and average loads for 10 mm of displacement were 1033, 1884 and 2013 N, respectively. Group 2 and 3 had the strongest fixation constructs although there was no statistically significant difference between these two groups (p=0.452). Group 2 and 3 were superior to Group 1 in terms of loads for 10 mm of displacement. There was no significant difference between Group 2 and 3 in this regard (p=0.397). Iliosacral screws are superior to bilateral S1 pedicle fixation through posterior tension band plating. However, the combination of tension band plating with iliosacral screw fixation does not improve the stability of the posterior pelvic ring.

A Biomechanical Comparison of Ipsilateral and Contralateral Pedicle Screw Placement for Modified Triangular Osteosynthesis in Unstable Pelvic Fractures

Iliosacral fixation of unstable pelvic fractures does not produce enough stability to allow for immediate postoperative weight bearing. Triangular osteosynthesis creates additional resistance to vertical displacement and rotation. A disadvantage is the loss of the L5/S1 motion segment. We propose a modification of the standard triangular osteosynthesis construct in which the contralateral S1 pedicle is used. As the ipsilateral L5 pedicle is unavailable for fixation in a saw-bones composite pelvic model, we compared ipsilateral and contralateral S1 pedicle screw constructs. We hypothesized that ipsilateral and contralateral S1 pedicle screw constructs would demonstrate no difference in displacement or rotation. Seven saw bones pelvic models were tested. A 5-mm vertical fracture gap was created through the left sacrum while the pubic symphysis was completely dissociated. Each pelvis was tested sequentially in 4 triangular osteosynthesis configurations: ipsilateral S1 screw with anterior plate, contralateral S1 screw with anterior plate, contralateral S1 screw without anterior plate, and ipsilateral S1 screw without anterior plate. Specimens were cyclically loaded from 100-200 N at 0.25 Hz for 25 cycles and then loaded up to 300 N at 10 mm/min while displacement and rotation at the sacral and pubic fracture sites were measured. There was no difference in any of the displacement measures between ipsilateral and contralateral constructs. When comparing rotation, the contralateral configuration experienced significantly less rotation than the ipsilateral configuration with and without the anterior plate applied. Within the limitations of the current model, contralateral S1 constructs for modified triangular osteosynthesis were biomechanically equal to ipsilateral constructs in preventing displacement and superior in preventing rotation.

Sacral Fracture After Instrumented Lumbosacral Fusion

Retrospective comparative study. To examine the incidence and characteristics of key spinopelvic parameters that are correlated with sacral fracture development after lumbosacral fusion. Sacral fracture is a possible complication of instrumented lumbosacral fusion and this has recently been documented in the literature. Preoperative awareness of risk factors concerning spinopelvic parameters and sacral fracture may aid in surgical planning to prevent its occurrence. All patients who underwent instrumented lumbosacral fusion from L2 or above, between 2010 and 2011 at Gakkentoshi Hospital, were included. A total of 116 patients (47 men and 69 women) were evaluated in this study. Average age at surgery was 71 years, and the average follow-up period was 19 months. The average number of fixed segments was 5, and the average time interval between index surgery and sacral fracture development was 42 days. Notably, sacral fractures were identified in 5 patients (4.3%), all of whom were women. We, therefore, compared the 2 groups of female patients (fracture group, n = 5 vs. nonfracture group, n = 64). The fracture group had a substantially higher mean pelvic incidence (PI) than the nonfracture group (72° ± 8° vs. 51° ± 12°, respectively, P < 0.01). The fracture group also had a larger postoperative lumbar lordosis (LL)-PI mismatch than the nonfracture group (-26° ± 7° vs. -7° ± 18°, respectively, P < 0.01). The current review of our patients informs appropriate preoperative planning in cases involving lumbosacral fusion for postmenopausal women with a high PI. Surgeons should plan to achieve large increases in LL to restore not only spinopelvic harmony but also to avoid postoperative sacral fracture. For such patients, because it is difficult to consistently achieve a sufficiently large LL, we recommend prophylactic iliosacral fixation to protect the sacrum. 4.

Ureteral injury after percutaneous iliosacral fixation: a case report and literature review

We report a case of right ureter injury in an 11-year-old girl after a percutaneous iliosacral screwing with non–computer-assisted fluoroscopic guidance. The indication was a pelvic ring fracture, C1-1 in the Tile modified AO classification (J Am Acad Orthop Surg. 1996;4:143-151). The mechanism was a ski accident. A percutaneous iliosacral screwing was performed to stabilize the right iliac wing fracture. Twelve days after the initial trauma, a right ureter tear was highlighted, just opposite the fourth lumbar vertebra. Uneventful spontaneous healing of the ureteral injury site occurred following double J-stent catheterization.