Early fixation of the vertically unstable pelvis: the role of iliosacral screw fixation of the posterior lesion

Single trans-iliac trans-sacral screw (STITSS) versus dual iliosacral screws (ISS) in fixation of unstable pelvic ring disruptions

OBJECTIVE

To compare between single trans-iliac trans-sacral screw versus dual ilio-sacral screws in Management of unstable pelvic ring disruptions after achieving reduction, to facilitate union of the fracture and early mobilization.

METHODS

In a retrospective cohort study that was done in Assiut University hospital trauma unit between May 2018 to September 2020, 36 patients with unstable fracture pelvis were included in the study. Single trans-iliac trans-sacral screws were done in 16 cases while two ilio-sacral screws were done for the rest of cases. Age ranged from 18 to 57 years old, with exclusion of patients with spino-pelvic dissociation, comminuted fractures, chronic uncontrolled co-morbidities, bilateral sacral fractures. Follow up of the patients radiologically using plain X-ray and Computed Tomography scan to identify union of fractures were reported. Functional follow-up using Majeed score and Visual analogue scale were reported with allowance of weight bearing as tolerated.

RESULTS

The two groups were comparable in terms of baseline characteristics, including age, sex, and comorbidities. A significant difference was observed in Tile classification between the groups (P = 0.05), while there was no significant difference in Denis classification (P = 0.29). Operative parameters such as surgical time, fluoroscopy time, and blood loss were similar between the two groups (P > 0.05). Outcome analysis revealed that patients in the STITSS group experienced significantly less pain at six weeks post-surgery, with lower VAS scores (4.31 ± 0.87 vs. 6.38 ± 1.31; P = 0.000). However, by 3 and 6 months, the VAS scores showed no significant differences between the groups (P > 0.05). Additionally, functional outcomes measured by the Majeed score were significantly better in the STITSS group at six weeks (61.64 ± 8.55 vs. 53.15 ± 7.80; P = 0.037). Similar to pain scores, the Majeed scores equalized between the groups at 3 and 6 months, with no significant differences noted.

CONCLUSION

The study findings indicate that STITSS fixation offers better early outcomes in terms of pain relief and functional recovery compared to dual ilio-sacral screw fixation. Despite the technical challenges associated with STITSS, it allows for faster rehabilitation and a quicker return to functional activities. In the long term, however, both techniques demonstrate comparable results. Further research is needed to validate these findings and optimize fixation strategies for unstable pelvic fractures.

Treatment of Type IV Fragility Fractures of Pelvis With Robotic-Assisted Minimally Invasive Triangular Fixation

OBJECTIVE

Type IV fragility fractures of pelvis (FFP IV) are serious and complicated and the treatment is challengeable. Robotic-assisted minimally invasive triangular fixation (RoboTFX) is a new and advanced technique to treat this injury. The objective of this report is to evaluate the clinical outcomes of FFP IV treated with RoboTFX.

METHODS

From March 2017 to December 2022, 22 consecutive patients with FFP IV were included in the study. Patients were divided into two groups according to the surgical method employed (RoboTFX or robotic-assisted minimally invasive iliosacral screws, RoboISS). Between two groups, we compared clinical data on operation time, intraoperative bleeding, intraoperative fluoroscopy time, favorable fracture healing rate, implant loosening rate, and Majeed pelvic outcome score.

RESULTS

All operations were undertaken from 3 to 15 days (average 5.7 ± 1.7 days) following primary injuries. All patients were followed up continuously 15 months. The average surgical time was 125.3 ± 15.5 (55-190) min in group RoboTFX, 137.1 ± 17.2 min in group RoboISS (p > 0.05). The average amount of intraoperative bleeding was 320.4 ± 25.2 (50-550) mL in group RoboTFX, 302.4 ± 21.5 (50-500) mL in Group 2 (p > 0.05). The average intraoperative fluoroscopy time of the two groups was 23.3 ± 4.5 (15-35) s in group RoboTFX and 40.3 ± 3.8 (10-75) s in group RoboISS (p < 0.05). No patients experienced loss of reduction, 5 of 40 screws had implant loosening in group RoboTFX, meanwhile 13 of 48 screws had implant loosening in Group 2. Four of 20 vertical sacral fractures were healed undesirable including 2 nonunion and the favorable healing rate of 80% in group RoboTFX, meanwhile 8 of 24 fractures were undesirable including 4 nonunion and the favorable healing rate was 66.7% in group RoboISS. Implant loosening rate in the RoboTFX group were all significantly better than those of the RoboISS group (p < 0.05). There were no occurrences of wound infection in both groups, and Majeed scores for the last follow-up were 76.2 ± 3.4 in group RoboTFX and 74.2 ± 2.7 in group RoboISS (p > 0.05).

CONCLUSION

RoboTFX has the advantages of less intraoperative fluoroscopy and implant loosening rate compared to RoboISS which is better than other methods. We thus recommend RoboTFX as an effective option for treating FFP IV. However, the indications of its operation should be strictly evaluated.

Traumatic lumbosacral instability: part 2-indications and techniques for surgical management

Traumatic lumbosacral instability (TLSI) refers to a traumatic disruption of the axial skeleton at the level of the lumbosacral motion segment and/or sacrum, resulting in mechanical separation of the caudal spinal column from the posterior pelvic ring. Managing TLSI and its four underlying conditions poses unique challenges among spinal and pelvic injuries. This second part of a two-part series focuses on treatment strategies and decision making in TLSI, with an emphasis on surgical stabilization techniques. The primary objectives of this article are to: (1) elucidate factors influencing clinical decision-making, (2) synthesize current treatment options for the injury patterns underlying TLSI, and (3) briefly outline expected outcomes and complications.

Closed Reduction and Minimally Invasive Fixation for the Treatment of Bilateral Displaced Posterior Pelvic Ring Disruption

OBJECTIVE

Close reduction and internal fixation have gained popularity for the treatment of pelvic fractures. However, the closed reduction of bilateral displaced posterior pelvic ring disruption is a great challenge even for the most experienced surgeon. In this study, we describe in detail a novel unlocking closed reduction technique (UCRT) frame that allows strong traction for bilateral posterior pelvic ring displacement and presents preliminary clinical outcomes.

METHODS

We retrospectively reviewed 32 patients with bilateral displaced posterior pelvic ring disruptions (AO/OTA 61-C2 and C3) who were initially treated with this technique between July 2017 and July 2022. According to the AO/OTA classification, there were 9 cases (28.12%) of 61-C2, and 23 cases (71.88%) of 61-C3. There were 11 males, 21 females, with an average age of 38.1 years. The interval from injury to operation was 4-27 days, with a cut-off of 12.5 days (receiver operating characteristic curve). Operative time, blood loss, and postoperative radiographic findings were recorded. The functional outcomes and complications were followed.

RESULTS

A total of 30 (93.8%) patients achieved successful closed reduction, whereas 2 required open reduction. The successful closed reduction rate was 95.5% (21/22) in patients whose injury-to-operation time was less than 12.5 days. The vertical displacement percent correction of the obviously displaced hemipelvis was 70.20% ± 16.79% on average. The average degree of pelvic deformity correction was 64.86% ± 17.71%. Thirty patients were followed up for at least 12 months (12-36 months), and no complications of nonunion or redisplacement were observed. The Matta-Tornetta scoring standard revealed that the excellent (25/30) and good (4/30) rate was 96.7%. The Majeed clinical efficacy score revealed that the overall excellent and good rate was 100%. One patient had INFIX-related infection, and 2 reported numbness in the lateral thigh. The numbness was improved after INFIX removal.

CONCLUSIONS

This study presents an updated technique for closed reduction using a UCRT frame for bilateral posterior pelvic ring disruption, which has been shown to be effective, as indicated by excellent surgical and functional outcomes.

Which screw corridors can be used for bilateral fragility fractures of the pelvis with a transverse fracture component (FFP IVb)?

BACKGROUND

Fragility fractures of the pelvis are becoming increasingly important in an ageing society. However, they are under-represented in the current research literature. In particular, unstable bilateral fragility fractures of the sacrum (FFP IVb) benefit from surgical treatment, but individual fracture patterns need to be considered in the surgical decision. This study describes the sacral anatomy in patients with FFP IVb pelvic fractures, with particular emphasis on the identification and evaluation of possible trans-sacral screw corridors, with particular emphasis on the transverse fracture components.

METHODS

Design: Retrospective clinical study.

SETTING

Level 1 trauma center. Patient Selection Criteria: The study reviewed 100 patients admitted for bilateral FFP with a transverse fracture between 01 / 2013 and 11 / 2023 that had a preoperative computed tomography (CT) of the pelvis including the fifth vertebra, treated with FFP IVb using preoperative multiplanar CT scans to analyze sacral anatomy. Outcome Measures and Comparisons: Sacral types and transitional abnormalities were classified, and corridor dimensions for S1 and S2 were measured, including estimated bone density using Hounsfield units. Bone corridors ≥ 8 mm were considered adequate. In addition, possible trans-sacral screw corridors were evaluated, taking into account the transverse fracture component.

RESULTS

While large trans-sacral screw corridors (≥ 8 mm) for S1 and S2 were identifiable in most cases, the actual feasibility for screw placement was limited due to the transverse fracture component's location, resulting in meaningful corridors in only 80 % for S1 and 47 % for S2. Additionally, in 4 % of patients without an S1 corridor, trans-sacral screw fixation was deemed inadequate due to the fracture line passing through S2.

CONCLUSIONS

These results indicate that not all FFP IVb fractures can be effectively stabilized using trans-sacral screw or bar fixation, necessitating alternative techniques for some cases. Furthermore, precise preoperative planning is essential for the management of these fractures due to complexity of anatomy. To identify the most suitable treatment approaches, further clinical studies are required.

LEVEL OF EVIDENCE

III.

Iliosacral screw osteosynthesis - state of the art

Iliosacral screw osteosynthesis is a widely recognized technique for stabilizing unstable posterior pelvic ring injuries, offering notable advantages, including enhanced mechanical stability, minimal invasiveness, reduced blood loss, and lower infection rates. However, the procedure presents technical challenges due to the complex anatomy of the sacrum and the proximity of critical neurovascular structures. While conventional fluoroscopy remains the primary method for intraoperative guidance, precise preoperative planning using multiplanar reconstructions and three-dimensional volume rendering is crucial for ensuring accurate placement of iliosacral or transsacral screws. Particular attention must be given to the preoperative evaluation of both the iliosacral and transsacral corridors, as anatomical variations may restrict the available space for screw insertion. This review aims to highlight the essential aspects of sacroiliac osteosynthesis, with a focus on the critical role of thorough preoperative planning and its impact on achieving successful surgical outcomes.

A Comparative Study of Functional Outcomes in Unstable Pelvic Ring Fractures Treated With Internal Fixator (INFIX) With and Without Sacroiliac Joint Screw Fixation

Introduction Despite constituting only 3-8% of orthopedic trauma cases, pelvic injuries are associated with high mortality rates, emphasizing the critical need for stable fixation rather than merely anatomical alignment. The use of an anterior, subcutaneous, internal pelvic fixator (INFIX), a novel technique, has shown promise in treating these injuries. Posterior pelvic ring injuries are challenging because they require a significant level of surgical training and technical expertise, and each treatment method has disadvantages. The aim of this study is to compare the clinical and biomechanical outcomes of INFIX with and without sacroiliac screw fixation for unstable pelvic fractures. Methods and methodology Retrospectively, we selected 20 patients with unstable pelvic ring injuries who had come to a high-volume tertiary care hospital and medical college in the state of Maharashtra, India. All the patients were operated on with INFIX; 10 with a sacroiliac joint screw and 10 without a sacroiliac joint screw. We followed up with the patients for six months and evaluated them according to the Majeed score. Results Functional outcomes differed little between INFIX patients operated on with and without a sacroiliac joint screw. However, morbidity, hospital stay, the need for ICU, radiation exposure, and technical ease of surgery were improved in INFIX patients without the sacroiliac screw procedure. We noted an average Majeed score of 78 in the INFIX-alone group and 77.2 in the group that received INFIX with a sacroiliac joint screw. Six months after the surgery, the patients showed signs of a stable bony union, had achieved a full range of motion, and reported no problems in their day-to-day work. Conclusion Although this was a short-term study, we conclude that INFIX without a sacroiliac joint screw showed a comparable functional outcome compared to INFIX with a sacroiliac joint screw. Patients with INFIX alone showed better results; they had reduced surgical time, reduced radiation exposure, and less evidence of neurological harm to the L5-S1 nerve root. The procedure was less complicated and easier for surgeons to learn. Its simplicity and speed were especially beneficial for obese patients.

Long-Term Follow-Up after Iliosacral Screw Fixation of Unstable Pelvic Ring Fractures

(1) Background: High-energy injuries of the pelvic ring are rare. The wide application of iliosacral screw fixation of the posterior pelvic ring is relatively new. The aim of the present study was to evaluate the long-term quality of life. (2) Methods: All patients treated with an iliosacral screw for a posterior pelvic ring stabilization after high-energy trauma at a level 1 trauma center between 2005 and 2015 were included. Pelvic ring injuries were classified according to the Tile classification adapted by AO/ASIF. The clinical evaluation included the patient-oriented questionnaires surveys of the Majeed Score, Iowa Pelvic Score (IPS), Work Ability Index (WAI), SF-36, EQ5D-5L. (3) Results: A total of 84 patients were included with a median follow-up of 130.1 months (IQR 95.0-162.0 months). The median ISS was 22.5 (IQR 16.0-29.0), mean Majeed Score 83.32 (SD ± 19.26), IPS 77.88 (SD ± 13.96), WAI 32.71 (SD ± 11.31), SF-36 PF 71.25 (SD ± 29.61) and EQ5D-5L 0.83 (SD ± 0.21). There was a notably difference between uni- and bilateral pelvic fractures (p = 0.033) as well as a correlation with the ISS (p = 0.043) with inferior functional outcome measured by IPS. (4) Conclusions: Long-term follow-up of iliosacral screw fixation of unstable pelvic ring fractures showed a good quality of life and functional outcome with equal EQ5D-5L results and inferior SF-36 physical functioning compared to the German population.

Guidance for dysmorphic sacrum fixation with upper sacroiliac screw based on imaging anatomy study: techniques and indications

OBJECTIVE

This study aimed to investigate the techniques and indications of upper sacroiliac screw fixation for the dysmorphic sacrum.

METHODS

The dysmorphic sacra were selected from 267 three-dimensional pelvic models. The dysmorphic sacra which couldn't accommodate a 7.3 mm upper trans ilio-sacroiliac screw were classified as the main dysmorphic sacra. Then, the size of the bone corridor, the length of the screw in the corridor, and the orientation of the screw were measured. The insertion point on the sacrum was identified by two bone landmarks.

RESULTS

totally, 30.3% of sacra were identified as the main dysmorphic sacra. The inclinations of the screw oriented from posterior to anterior were (21.80 ± 3.56)° for males and (19.97 ± 3.02)° for females (p < 0.001), and from caudal to cranial were (29.97 ± 5.38)° for males and (28.15 ± 6.21)° for females (p = 0.047). The min diameters of the corridor were (16.31 ± 2.40) mm for males and (15.07 ± 1.58) mm for females (p < 0.001). The lengths of the screw in the Denis III zone were (14.41 ± 4.40) mm for males and (14.09 ± 5.04) mm for females (p = 0.665), and in the Denis II+III zones were (36.25 ± 3.40) mm for males and (38.04 ± 4.60) mm for females (p = 0.005). The rates of LP-PSIS/LAIIS-PSIS were (0.36 ± 0.04) for males and (0.32 ± 0.03) for females (t = 4.943, p < 0.001). The lengths of LPM were (8.81 ± 5.88) for males and (-4.13 ± 6.33) for females (t = 13.434, p < 0.001).

CONCLUSION

When the sacrum has the features of "sacrum not recessed" and/or "acute alar slope", the conventional trans ilio-sacroiliac screw couldn't be placed safely. The inclination oriented from posterior to anterior and from caudal to cranial are approximately 20° and 30°, respectively. The bone insertion point locates in the rear third of the anterior inferior iliac spine to the posterior superior iliac spine. The sacroiliac screw is not recommended to fix the fractures in Denis III zone.

Biomechanical comparison of four triangular osteosynthesis fixations for unilateral vertical sacral fractures

To compare the stability and biomechanical characteristics of four commonly used triangular osteosynthesis techniques to treat unilateral vertical sacral fractures and provide a clinical application reference. Finite element models of Tile C-type pelvic ring injury (unilateral Denis II sacral fracture) were produced. In four models, sacral fractures were fixed with a combination of unilateral L5, unilateral L4, and L5 iliac lumbar fixation with lengthened or normal sacroiliac screws. The biomechanical properties of the four fixation models were measured and compared under bipedal stance and lumbar rotation. The fixation stability of the model with the lengthened sacroiliac screw was excellent, and the fracture end was stable. The stability of fixation using unilateral L4 and L5 segments was close to that of unilateral L5 segment fixation. Triangular osteosynthesis transverse stabilization devices using lengthened sacroiliac screws can increase the vertical stability of the sacrum after internal fixation and increase the stability of the fracture. When triangular osteosynthesis lumbar fixation segments were selected, simultaneous fixation of L4 and L5 segments versus only L5 segments did not significantly enhance the vertical stability of the sacrum or the stability of the fracture end.

Does iliosacral screw removal reduce postoperative pain in unstable pelvic fracture patients? A matched prospective cohort study

BACKGROUND

To compare pain and function in patients with unstable posterior pelvic fractures stabilized with posterior fixation who undergo iliosacral screw removal versus those who retain their iliosacral screws.

METHODS

A prospective observational cohort study identified 59 patients who reported pain at least 4 months after iliosacral screw fixation of an unstable posterior pelvic ring fracture from 2015-2019. The primary intervention was iliosacral screw removal versus a matched iliosacral screw retention control group. Patient-reported pain was measured with the 10-point Brief Pain Inventory, and patient-reported function was measured with the Majeed Pelvic Outcome Score. Both measured within 6 months of the intervention.

RESULTS

Before iliosacral screw removal, the mean pain was 4.7 (SD, 3.0) compared with 4.7 (SD, 3.0) in the matched control group. Following iliosacral screw removal, the average pain in the screw removal group was 3.7 (SD, 2.7) and 3.3 (SD, 2.5) in the matched control group. We found no evidence that iliosacral screw removal reduced pain in this population (mean difference, 0.2 points; 95% CI, -1.0 to 1.5; p = 0.71). In addition, the improvement in function after iliosacral screw removal was not statistically indistinguishable from zero (mean difference, 3.1 points; 95% CI, -4.6 to 10.9; p = 0.42).

CONCLUSIONS

The results suggest that iliosacral screw removal offers no significant pelvic pain or function benefit when compared with a matched control group. Surgeons should consider these data when managing patients with pelvic pain who are candidates for iliosacral screw removal.

Finite element analysis of sacral-alar-iliac screw fixation for sacroiliac joint dislocation

The percutaneous sacroiliac (SI) screw is a common fixation option for posterior ring disruption in pelvic fractures. However, SI screw placement is difficult and can injure adjacent neurovascular structures. The sacral-alar-iliac screw (SAI) is a safe, reliable free-hand sacral pelvic fixation technique. To investigate the biomechanical stability of SAI for SI joint dislocation, finite element analysis was performed in unstable Tile-Type B and C pelvic ring injuries. The displacement in S1 (fixation of a unilateral S1 segment with one SI screw), TS1 (fixation of the S1 segment with a transsacra 1 screw), TS2 (fixation of the S2 segment with a transsacra 2 screw), S1AI, and S2AI exceeded the normal SI joint mobility. Sufficient stability after SI joint dislocation was obtained with (TS1 + TS2), (TS2 + S1), (S1AI + S2AI + rod), (S1AI + S2AI), and (S1 + S2AI + S1 pedicle) fixation. The TS1 + TS2 group had the smallest displacement and lowest peak screw stress, followed by (S1 + S2AI + S1 pedicle) placement. Our findings suggest that SAI screws are a valuable option for SI joint dislocation.

Robotic guidance for percutaneous placement of triangular osteosynthesis in vertically unstable sacrum fractures: a single-center retrospective study

BACKGROUND

To evaluate the effectiveness and safety of robot-aided percutaneous triangular osteosynthesis combined with close reduction for vertically unstable sacrum fractures (VUSFs).

METHODS

The data on 21 patients of the VUSF were retrospectively analyzed from November 2016 to January 2021. According to Denis classification, there were 3 cases in zone I, 11 cases in zone II, and 7 case in zone III. The main perioperative indicators were recorded. The maximal angulation and displacement deviations of the screws were analyzed by comparing the planned trajectory with the actual position. Postoperative X-ray radiographs and CT scans were obtained for evaluating the reduction quality. Functional outcome was scored with Majeed criterion.

RESULTS

Fourteen patients of the unilateral VUSF and 7 patients of the bilateral VUSF underwent unilateral and bilateral triangular osteosynthesis with robotic assistance, respectively. No intraoperative neurovascular injuries and postoperative infection occurred. All patients were followed up for at least 12 months. The average operation time of posterior pelvic ring was 111.4 min, with the mean intraoperative bleeding of 110.5 ml. A total of 58 pedicle and iliosacral screws were implanted with robotic assistance. Of those, 52 screws were in the cancellous bone except 4 pedicle and 2 iliosacral screws cutting the cortical bone. The angulation and displacement deviations of the screws were 4.2° ± 2.5° and 1.7 ± 0.9 mm, respectively. The average displacement of the sacral fracture was reduced from 19.7 mm preoperatively to 3.1 mm postoperatively. According to Matta's criterion, the reduction quality was graded as "excellent" in 13 patients and "good" in 8. All sacral fractures healed within 6 months except one fracture with nonunion. The mean Majeed score at the last follow-up was 89.6.

CONCLUSIONS

Robot-aided triangular osteosynthesis combined with close reduction provide a safe and reliable option for percutaneous treatment of the fresh VUSF, with a high accuracy of iliosacral and pedicle screw implantation except insertion of iliac screws. Meanwhile, the technique may help to reduce incision-related complications.

Breakage risk of different sacroiliac screws in unilateral sacral fractures a finite element analysis

Objective

To compare the breakage risk of lengthened sacroiliac screws and ordinary sacroiliac screws to treat unilateral vertical sacral fractures and provide a reference for clinical application.

Methods

A finite element model of Tile C pelvic ring injury (unilateral type Denis II fracture of the sacrum) was produced. The sacral fractures were fixed with a lengthened sacroiliac screw and ordinary sacroiliac screw in 6 types of models. The maximal von Mises stresses and stress distributions of the two kinds of screws when standing on both feet were measured and compared.

Results

The maximal von Mises stress of the lengthened screw was less than that of the ordinary screw. Compared with ordinary screw, the stress distribution in the lengthened screw was more homogeneous.

Conclusions

The breakage risk of screws fixed in double segments is lower than that of screws fixed in single segments, the breakage risk of lengthened screws is lower than that of ordinary screws, and the breakage risk of screws fixed in S2 segments is lower than that of screws fixed in S1 segments.

Lumbopelvic Fixation with Bridged Distal Iliac Screws for Vertically Unstable Sacral Fractures

Purpose

The purpose of this study is to evaluate preliminary outcomes of vertically unstable sacral fractures treated by lumbopelvic fixation (LPF) augmented transiliac bridged screws.

Methods

From April 2017 to December 2019, fifteen consecutive patients with vertically unstable sacral fractures who had undergone LPF augmented transiliac bridged screws were enrolled. The radiological assessment included standard lumbopelvic x-rays and pelvic computed tomography (CT) to evaluate the lumbosacral angle (LSA), sacral kyphosis angle (SKA), lumbar lordosis angles (LLA) and Matta's reduction criterias (MRC). Clinical and neurologic impairment outcomes were evaluated by the Majeed grading scale (MGS) and Gibbons criterias, respectively.

Results

All patients were followed for an average of 18 months (range, 14-25). All sacral fractures eventually healed and implant failure did not occur in any patient, though there were two patients with a loss of reduction (< 5 mm) during the follow-up period. According to the MRC, the results were excellent on 14 sides, good on five sides, and fair on one side. The MGS mean score was 82 points (range, 49-98 points); the results were excellent in nine cases, good in four cases, and fair in two cases. There was no statistically significant difference in SKA and LLA in preoperative and postoperative final controls. The preoperative and postoperative LSA were 72 ± 13.9 and 44.1 ± 11.3, respectively, and a statistically significant improvement was observed (p = 0.01).

Conclusion

In vertically unstable sacrum fractures, we believe that LPF augmented with transiliac bridging technique may expedite the reduction of vertical sacrum fracture and offers a reinforced fixation choice.

Prospective Characterization of Pain and Function in Patients With Unstable Pelvic Fractures Treated With Posterior Screw Fixation

OBJECTIVES

Describe patient-reported pain and function within 24 months of a pelvic fracture treated with posterior screw fixation and identify factors associated with increased pain.

DESIGN

Prospective case series.

SETTING

Academic trauma center.

PATIENTS/INTERVENTION

Eighty-eight patients with adult pelvic fracture treated with sacroiliac or transiliac screws.

MAIN OUTCOME MEASURES

Average pain measured with the Brief Pain Inventory (BPI); function measured with the Majeed Pelvic Outcome Score from 6 to 24 months postinjury.

RESULTS

The mean pain from 6 to 24 months postinjury was 2.22 on the 10-point BPI scale (95% CI, 0.64-3.81). Sixty-nine patients (78.4%) reported mild to no pain at 6 months; 12 (13.6%) patients had severe pain. Two years after injury, 71 patients (80.6%) exhibited mild to no pain. Within 24 months of injury, the mean pelvic function was 71 on the 100-point Majeed scale (95% CI, 60-82). Half of the sample (n = 44) had good to excellent pelvis function by 6 months postinjury; 55 patients (62.5%) attained this level of function by 24 months. A history of chronic pain (1.31; 95% CI, 0.26-2.37; P = 0.02), initial fracture displacement (≥5 mm) (0.99; 95% CI, 0.23-1.69; P = 0.01), and socioeconomic deprivation (0.28; 95% CI, 0.11-0.44; P < 0.01) were significantly associated with increased pain.

CONCLUSION

Our findings suggest that most patients with unstable pelvic ring fractures treated with posterior screw fixation achieve minimal to no pelvis pain and good to excellent pelvic function 6-24 months after injury.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Biomechanical study of anterior and posterior pelvic rings using pedicle screw fixation for Tile C1 pelvic fractures: Finite element analysis

Objective

The purpose of this study was to analyse the biomechanical characteristics of pedicle screws with different placement methods and diameters in the treatment of Tile C1 pelvic fractures by finite element simulation technology and to compare them with the plate fixation model to verify the effectiveness of pedicle screw fixation.

Methods

A three-dimensional digital model of a normal pelvis was obtained using computed tomography images. A finite element model of a normal pelvis containing major ligaments was built and validated (Model 1). Based on the verified normal pelvis finite element model, a Tile C1 pelvic fracture model was established (Model 2), and then a plate fixation model (Model 3) and a pedicle screw fixation model with different screw placement methods and diameters were established (Models 4–15). For all pelvic fracture fixation models, a vertical load of 500 N was applied on the upper surface of the sacrum to test the displacement and stress distribution of the pelvis in the standing state with both legs.

Results

The finite element simulation results showed the maximum displacement of Model 1 and Models 3–15 to be less than 1 mm. The overall maximum displacement of Models 4–15 was slightly larger than that of Model 3 (the maximum difference was 177.91×10⁻³ mm), but the maximum displacement of iliac bone and internal fixation in Models 4–15 was smaller than that of Model 3. The overall maximum stress (maximum stress of the ilium) and maximum stress of internal fixation in Models 4–15 were less than those in Model 3. The maximum displacement difference and maximum stress difference at the fracture of the pubic ramus between each fixed model were less than 0.01 mm and 1 MPa, respectively. The greater the diameter and number of pedicle screws were, the smaller the maximum displacement and stress of the pelvic fracture models were.The maximum displacement and stress of the pelvic fracture models of the screws placed on the injured side of the pubic region were smaller than the screws on the healthy side.

Conclusion

Both the anterior and posterior pelvic rings are fixed with a pedicle screw rod system for treatment of Tile C1 pelvic fractures, which can obtain sufficient biomechanical stability and can be used as a suitable alternative to other implants.The greater the diameter and number of pedicle screws were, the greater the pelvic stability was, and the greater was the stability of the screws placed on the injured side of the pubic region than the screws on the healthy side.

Quantifying Urinary and Sexual Dysfunction After Pelvic Fracture

OBJECTIVES

To quantify the severity of urinary and sexual dysfunction and to evaluate the relationship between urinary and sexual dysfunction, injury, and treatment factors in patients with pelvic fracture.

DESIGN

Prospective cohort study.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

One hundred thirteen patients with surgically treated pelvic fracture (65.5% OTA/AO 61B fractures; 7 open fractures; 74 men).

INTERVENTIONS

Surgical pelvic stabilization.

MAIN OUTCOME MEASURES

The 36-Item Short Form Health Survey and International Consultation Incontinence Questionnaire responses were collected at baseline, 6 months, and 1, 2, and 5 years. Patients were scored on symptoms of voiding and incontinence, and filling (for women), to derive urinary function. Sexual function was scored as a single domain. Both genders reported urinary and sexual bothersome symptoms. Regression analysis was used to isolate the importance of predictive factors on urinary and sexual function, urinary and sexual bother, and their impact on quality of life.

RESULTS

Patients with pelvic fracture have significant urinary and sexual dysfunction, which is sustained or worsens over time. Male urinary function was predicted by Injury Severity Score (P = 0.03) and 61C fracture (odds ratio: 3.23, P = 0.04). Female urinary function was predicted by urinary tract injury at admission (odds ratio: 7.57, P = 0.03). Neurologic injury and anterior fixation were identified as significant predictors for male sexual function and sexual bother, whereas urological injuries were important in predicting female urinary and sexual bother (P < 0.01). Sexual function (P = 0.02) and sexual bother (P < 0.001) were important predictors of overall mental well-being in men.

CONCLUSIONS

Urinary and sexual dysfunction are prevalent and sustained in men and women and do not follow the prolonged slow recovery trajectory seen in physical function. Male urinary and sexual dysfunction was closely tied to neurologic injury, whereas female urinary and sexual dysfunction was predicted by the presence of a urinary tract injury. Urinary and sexual dysfunction were important to overall mental well-being in men.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

What's old is best again Is anterior plating best for fixation of type-C pelvic fractures? A systematic review and meta-analysis

BACKGROUND

Type-C pelvic fractures are a rare but potentially fatal injury that often leads to poor outcomes, despite surgical fixation. Many fixation methods are used but the optimal method remains contentious, with failure and complications common. This study compared outcomes for each fixation method.

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A search of studies which reported on outcomes after surgically treated type-C pelvic fractures was undertaken. Data retrieved included fixation method, length of follow up, surgical revision, and complications rates (hardware breakage, post-operative outcomes, screw mal-positioning, screw loosening, loss of reduction and infection). Study quality was assessed using the Methodological Index for Non-Randomised Studies (MINORS). Pooled revision, outcome and complication rates were calculated using a quality-adjusted model in MetaXL 5.3.

RESULTS

Fifty-two studies met the inclusion criteria representing 1567 patients and 7 fixation methods. The meta-analyses demonstrated high rates of 'less-than-good' outcomes for most fixation methods, with a higher rate for bilateral injuries (overall 23%; unilateral 21% v bilateral 41%). The mean pooled rate for surgical revision rate was 4%, hardware breakage 3%, screw mal-positioning 2%, screw loosening 3%, loss of reduction 5% and infection 4%. Each fixation method had different performance profiles; however, anterior plating outperformed all other fixation methods for patient outcomes, with a 'less-than-good' rate of just 7% vs the pooled mean of 23% and demonstrated at or below pooled mean rates for all complications except revision which was 5%.

CONCLUSIONS

Post-operative outcomes for surgically treated type-C pelvic fractures revealed a 'less-than-good' pooled outcome rate of 23% and a revision rate of 4%. Anterior plates outperformed most other systems particularly for patient reported outcomes. Pooled revision, patient-reported outcome and complication rates for type-C pelvic fractures have not previously been reported and these data provide a benchmark for practice and future research.

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.

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.

Percutaneous Robot-Assisted versus Freehand S2 Iliosacral Screw Fixation in Unstable Posterior Pelvic Ring Fracture

OBJECTIVES

To assess the efficiency, safety, and accuracy of S₂ (IS) screw fixation using a robot-assisted method compared with a freehand method.

METHODS

This is a retrospective clinical study. We analyzed the patients treated with S₂ IS screw fixation for unstable pelvic fractures from January 2016 to January 2019 in our institution. Sixty-three patients (17 men and 46 women) aged between 21 and 55 years (with an average age of 39.22 ± 9.28) were included in this study. According to the Tile classification, there were 26 (41.3%) type B fractures and 37 (58.7%) type C fractures. All patients were divided into robot-assisted (RA) group (38 patients) or the traditional freehand (FH) group (25 patients). In RA group, the S₂ IS screws were implanted with a robot-assisted technique. And S₂ IS screws were implanted with a traditional freehand technique in FH group. The screw-related complications were recorded during and after the surgery. The position of all screws and fracture reduction was assessed by postoperative CT scans according to the Gras classification. The number of guide wire attempts and the radiation exposure for S₂ screw implantation during operation were also recorded. Finally, the Matta standard was used to evaluate the fracture reduction of the IS joint.

RESULTS

A total of 89 IS screws were implanted into S2 iliosacral joint. Fifty-four screws were placed by RA (38 patients) and 35 screws were by FH (25 patients). There was no difference between the two groups with respect to demographic data. There was no screw-related complications or revision surgery in any group. In terms of screw placement, the excellent and good rate was 100% in the RA group, better than that in the FH group where it was only 85.7% (P < 0.001). The fluoroscopy time was 8.06 ± 3.54 s in RA group, which was much less than that in the FH group (27.37 ± 8.82 s, P < 0.001). The guide wire attempts in the RA group (0.685 ± 0.820) were much less than those in the FH group (5.77 ± 3.34) (P < 0.001). Both the fluoroscopy time per screw and the number of guide wire attempts in the RA group were much less than those in the FH group (P < 0.001). The overall postoperative excellent and good rate of Matta standard in RA and FH groups were 86.8% (34/4) and 90.0% (23/25), respectively (P = 0.750), and there was no statistical difference.

CONCLUSION

The robot-assisted surgery is an accurate and minimally invasive technique. S₂ IS screw implantation assisted by TiRobot to treat the posterior pelvic ring fractures, have a high success rate than the freehand technique. Percutaneous RA S₂ IS screw fixation for unstable posterior pelvic ring injuries is safe and clinically feasible and has great clinical application value.

An anatomical study defining the safe range of angles in percutaneous iliosacral and transsacral screw fixation

Percutaneous iliosacral screw fixation and transsacral fixation are challenging procedures requiring extensive knowledge of sacral anatomy to avoid damaging nearby neurovascular structures. Greater knowledge of anatomical screw trajectory and size allowances would be helpful to guide surgical placement. An anatomical study of 40 cadaveric sacra in specimens ages 18-65 was performed. Three-dimensional surface scans were obtained, and computer modeling software was used to simulate a 7.3 mm diameter screw with 1 mm buffer inserted orthogonal to the sacroiliac joint in the pelvic inlet and outlet views. Transsacral screws were also inserted into S1 and S2 vertebrae. For screws orthogonal to the sacroiliac joint, the overall mean screw insertion angle was 4.1° ± 7.5° (range, -18.3° to 22.0°) in the inlet view in the posterior to anterior direction, and 21.7° ± 5.1° (range, 8.2°-36.3°) in the outlet view in the caudal to cranial direction. Before breaching the sacrum, the range of sacral tunnel lengths was between 31.1 and 70.1 mm with a range of diameters between 9.3 and 13.3 mm. Transsacral screws inserted into either the S1 or S2 vertebrae did not breach the sacrum in 40% (16/40) at each level. 30% (12/40) of sacra could not safely accommodate both S1 and S2 transsacral screws. There is an initial screw insertion angle range of -4° to 12° in the inlet view and 16°-27° in the outlet view. There was always adequate size to accept a 7.3 mm or larger screw.

One sacroiliac screw for posterior ring fixation in unstable pelvic fractures

Unstable pelvic injuries are considered uncommon and they are usually associated with high rate of morbidity and mortality. High energy blunt trauma and falling from height are usually the main mechanism of injury. It is a retrospective study that was performed in academic level I trauma center. From September 2015 to December 2019, a consecutive series of 26 patients (7 females), with average age of 32 years with unstable pelvic fracture were included in this study. All patients underwent reduction and percutaneous fixation with one sacroiliac screw posteriorly for each sacroiliac joint and anterior arch fixation of the pelvic ring with either platting or external fixator. The average duration of follow up was 36 months. Clinical results: at the final follow-up, all patients had complete radiological healing of the fractures. The subjective functional assessment yielded excellent for twenty-two patients, good for two patients and fair for two patients. Posterior arch fixation of the pelvic ring with one sacroiliac screw beside anterior arch fixation in unstable fracture pelvis is a sufficient fixation method to maintain the requiring stability to allow complete union of the fracture. Level of Evidence: Therapeutic Level III.

Is Anterior Plating Superior to the Bilateral Use of Retrograde Transpubic Screws for Treatment of Straddle Pelvic Ring Fractures? A Biomechanical Investigation

Background: Fractures of the four anterior pubic rami are described as “straddle fractures”. The aim of this study was to compare biomechanical anterior plating (group 1) versus the bilateral use of retrograde transpubic screws (group 2). Methods: A straddle fracture was simulated in 16 artificial pelvises. All specimens were tested under progressively increasing cyclic loading, with monitoring by means of motion tracking. Results: Axial stiffness did not differ significantly between the groups, p = 0.88. Fracture displacement after 1000–4000 cycles was not significantly different between the groups, p ≥ 0.38; however, after 5000 cycles it was significantly less in the retrograde transpubic screw group compared to the anterior plating group, p = 0.04. No significantly different flexural rotations were detected between the groups, p ≥ 0.32. Moreover, no significant differences were detected between the groups with respect to their cycles to failure and failure loads, p = 0.14. Conclusion: The results of this biomechanical study reveal less fracture displacement in the retrograde transpubic screw group after long-term testing with no further significant difference between anterior plating and bilateral use of retrograde transpubic screws. While the open approach using anterior plating allows for better visualization of the fracture site and open reduction, the use of bilateral retrograde transpubic screws, splinting the fracture, presents a minimally invasive and biomechanically stable technique.

Comparison of lumbopelvic fixation and iliosacral screw fixation for the treatment of bilateral sacral fractures

Background

Bilateral sacral fractures result in traumatic disruption of the posterior pelvic ring. Treatment for unstable posterior pelvic ring fractures should aim for fracture reduction and rigid fixation to facilitate early mobilization. Iliosacral screw fixation (ISF) and lumbopelvic fixation (LPF) were recommended for the treatment of these injuries. No algorithm or gold standard exists for surgery of these fractures.

Purpose

The purpose of this study was to evaluate the differences between ISF and LPF in bilateral sacral fractures regarding intraoperative procedures, complications and postoperative mobilization. The secondary aim was to determine whether demographics influence surgical treatment.

Methods

Over a 4-year period (2016–2019), 188 consecutive patients with pelvic ring injuries were treated at one academic level 1 trauma center and retrospectively identified. Fractures were classified according to the AO/OTA classification system. Seventy-seven patients were treated with LPF or ISF in combination with internal fixation of pubic rami fractures and could be included in this study. Comparisons were made between demographic and perioperative data. Infection, hematoma and hardware malpositioning were used as complication variables. Mobilization with unrestricted weight bearing was used as outcome variable. Follow-up was at least 6 months postoperatively.

Results

Operative stabilization of bilateral posterior pelvic ring injuries was performed in 77 patients. Therefore, 29 patients (females 59%) underwent LPF whereas 48 patients (females 83%) had bilateral ISF. The ISF group was older (76 yrs.) compared to the LPF group (62 yrs.) (p = 0.001), but no differences regarding BMI or comorbidities were detected. Time for surgery was reduced for patients who were treated with ISF compared to lumbopelvic fixation (73 min vs. 165 min; respectively, p < 0.001). But this did not result in reduced fluoroscopic time or radiation exposure. Overall complication rate was not different between the groups. Patients with LPF had a greater length of stay (p = 0.008) but were all weight bearing as tolerated when discharged (p < 0.001).

Conclusion

Bilateral posterior pelvic ring injuries of the sacrum can be sufficiently treated by LPF or ISF. LPF allows immediate weight bearing which may benefit younger patients and patients with an elevated risk for pneumonia or other pulmonary complications. Treatment with ISF reduces operative time, length of stay and postoperative wound infection. Elderly patients may be better suited for treatment with ISF if there is concern that the patient may not tolerate the increased operative time.

Three-dimensional morphometry of the first two sacral segments and its impact on safe transiliac-transsacral screw placement

INTRODUCTION

Percutaneous screw fixation of the posterior pelvic ring is a popular technique to treat unstable pelvic ring lesions. This technique is practicable in both, the high-energy pelvic ring fractures, mostly in the young population as well as the osteoporotic fractures in the elderly. Risk of the transiliac-transsacral screw positioning is that the critical area of nerve root exit has to be passed twice. For secure screw placement, without causing iatrogenic neurovascular injuries, the knowledge of distances to the narrowest areas is essential. Purpose of this anatomical study was to examine the optimal intraosseous screw placement for the first two sacral segments.

MATERIAL/METHODS

Images of uninjured pelves from 50 patients (64-line CT scanner) were evaluated. Then virtual transiliac-transsacral srews were positioned into the first two sacral segments. The distance from the screws' entrance points at the ilium's alar bone to the narrowest portion of the whole pedicle as well as the height and width in this area were measured. Descriptive statistics were used and gender related differences were evaluated using student T-test.

RESULTS

For the first sacral segment the distance to the narrowest zone amounted in mean 62.75 mm, respectively 63.31 mm, depending on the selected way of measurement. For the second segment the mean distance to the neuroforamina was on average 50.61 mm, respectively 51.54 mm. The average height in S1 measured 25.88 mm and the average width 25.49 mm. The average height for S2 was 17.54 mm and the average width 17.61 mm. We could not find any statistically significant gender correlation for the measured distances.

CONCLUSION

Results of this anatomical study may help in performing a safe surgical procedure.

Similar patient reported outcomes at long-term follow-up after external fixation versus internal fixation of the anterior ring component of APC injuries

PURPOSE

Unstable pelvic ring injuries produced by external rotation of the hemipelvis and a symphyseal disruption are most often treated with internal fixation of the anterior ring, with percutaneous treatment of the posterior ring as needed. In some clinical situations, patients are treated with external fixation for their anterior injuries and the long-term functional outcomes associated with external fixation are not well understood. We ask if there is a difference in functional outcome, between treatment of these injuries with internal versus external fixation, when measured at a minimum of three years after injury.

METHOD

This was a retrospective cohort study performed at a level one regional trauma center. Trauma database review identified 128 patients, with 70 subsequently excluded, with unstable anterior posterior compression (APC) pelvic ring injuries (OTA 61B2.3 & 61C1.2) treated with surgery with minimum three years of follow-up. An intervention of internal fixation versus external fixation of anterior pelvic ring was performed, and depending on the injury, supplemented with posterior iliosacral screw fixation. Main outcome was measured with the Majeed functional outcome score (0-100).

RESULTS

Patients treated with external fixation reported a Majeed score of 70 (95% CI 28-100) compared to 79 (95% CI 36-100) in those with internal fixation (p-value 0.28). Subgroups of the Majeed score were not significantly different (p value > 0.05). Open fractures, severity of injury, and ISS were worse in those treated with external fixation. There was no differential loss to follow-up. Conclusion Patients with unstable pelvic ring injuries with symphyseal disruptions treated with external fixation as definitive treatment versus internal fixation may fare no different in the long term.

First experiences with intraoperative CT in navigated sacroiliac (SI) instrumentation: An analysis of 25 cases and comparison with conventional intraoperative 2D and 3D imaging

BACKGROUND

Intraoperative imaging is regularly used for intraoperative reduction control and evaluation of the implant position in trauma surgery. 2D imaging is limited, especially in complex anatomical regions such as the pelvis. The introduction of mobile 3D C-arms (CBCT: cone-beam computed tomography) has significantly improved intraoperative assessment. Nevertheless, there are still limitations regarding the field of view and metal artifacts. The purpose of this study was to evaluate the potential of intraoperative computed tomography (iCT) in surgical treatment of sacroiliac (SI) injuries.

METHODS

Twenty-five cases with injuries of the posterior pelvic ring involving the SI region that were surgically treated with navigated SI screws using the mobile iCT Airo (Brainlab, Munich, Germany) were analysed. Subsequently, the data were compared with historical control groups (CBCT with and without navigation; 2D fluoroscopy only).

RESULTS

The average score for subjective image quality achieved using the Likert scale is significantly higher for the iCT (4.48 ± 0.65) than for the CBCT (3.04 ± 0.69) with p = 0.00. The average duration of surgery using iCT was 189.32 ± 88.64 min, which was not significantly different from the control groups (p = 0.14 - 0.70). The average fluoroscopy time using iCT was 81.96 ± 97.34 s, which was significantly shorter than in all of the control groups (p = 0.00 - 0.03). The rate for postoperatively detected complications after using iCT was 0% (n = 0). Compared with the 2D-only control group (25%; n = 1), there is a significant difference (p = 0.01). The remaining two control groups showed no significant differences (p = 0.09 - 0.19).

CONCLUSIONS

The iCT provides excellent image quality that allows reliable assessment of fracture reduction and implant placement even in complex anatomical regions. The radiation exposure for the medical staff is reduced by decreasing the fluoroscopy time without significantly prolonging the surgical time. Overall, the possibility of intraoperative correction improves clinical outcome and patient treatment in the long term.

Superior gluteal artery injury risk from third sacral segment transsacral screw insertion

OBJECTIVES

Iliosacral (IS) and transsacral (TS) screws are commonly used to stabilize pelvic ring injuries. The course of the superior gluteal artery (SGA) can be close to implant insertion paths. The third sacral segment (S3) has been described as a viable osseous fixation pathway (OFP) but the proximity of the SGA to the S3 screw path is unknown.

METHODS

Fifty uninjured patients with contrasted pelvic computed tomograms (CTA) were identified with an S3 path large enough for a 7.0 mm TS screw. Starting sites for S1 IS or TS, S2 and S3 TS screws were located on the volume rendered lateral CTA image and transferred onto the surface rendered 3D CTA with the SGA clearly visible. The distance from screw start sites to the SGA was measured. A distance less than 3.5 mm was considered likely for injury.

RESULTS

The average distances from screw start sites to the SGA were 23.0 ± 7.9 mm for S1 IS screws, 14.3 ± 6.4 mm for S2 TS screws and 25.9 ± 6.5 mm for S3 TS screws. No S1 IS screws, 5 S2 TS screws (10%), and no S3 TS screws were projected to cause injury to the SGA.

CONCLUSIONS

The osseous start site and soft tissue path for an S3 TS screw is remote from the SGA. The S1 IS and S3 TS pathways are further away from the SGA while the S2 TS pathway is closer and may theoretically pose a higher injury risk in patients with an available S3 OFP.

Minimally invasive internal fixation for unstable pelvic ring fractures: a retrospective study of 27 cases

Background

This study aimed to evaluate the radiographic and clinical outcomes of anterior subcutaneous internal fixation (INFIX) with or without posterior fixation for the treatment of unstable pelvic fractures.

Methods

Intraoperative blood loss, operation time, and duration of hospital stay were recorded, and fracture union and postoperative complications were evaluated. The fracture reduction quality was evaluated using the Matta score, pelvic deformity index (PDI), and pubic symphyseal width (PSW). In addition, the functional recovery and general quality of life were evaluated using the Majeed score and the 12-Item Short-Form Survey (SF-12), respectively. Furthermore, sacral nerve injury was evaluated using the Gibbons classification.

Results

Twenty-seven patients (14 males and 13 females) with an average age of 37.4 years were followed up for a mean of 22 months. The average operation time, median intraoperative blood loss, and average duration of hospital stay were 129 ± 47 min, 100 mL, and 22 ± 13 days, respectively. All patients achieved bony union with an average union time of 13.3 weeks. Furthermore, the average PDI and PSW were 0.07 ± 0.04 vs. 0.04 ± 0.03 (P = 0.009) and 1.15 ± 1.36 vs. 0.54 ± 0.17 (P = 0.048) before and after the operation, respectively. In 78% of the patients, the Matta or Majeed scores were excellent or good. The SF-12 physical and mental health scores were 45.1 ± 10.2 and 53.2 ± 6.3, respectively. Furthermore, one superficial surgical site infection, one loosening of INFIX, one lateral femoral cutaneous nerve irritation, one femoral nerve injury, and two implant discomforts due to the bar were noted. Among five patients with sacral nerve injuries, four were asymptomatic, and one just had paresthesia at the last follow-up.

Conclusion

INFIX with or without sacroiliac screws can achieve satisfactory radiographic and functional outcomes in the treatment of unstable pelvic ring fractures.

Trial registration

ChiCTR2000038812. Registered 04 October 2020. Retrospectively registered.

Biomechanical Effects of a Cross Connector in Sacral Fractures - A Finite Element Analysis

Background: Spinopelvic fractures and approaches of operative stabilization have been a source of controversial discussion. Biomechanical data support the benefit of a spinopelvic stabilization and minimally invasive procedures help to reduce the dissatisfying complication rate. The role of a cross connector within spinopelvic devices remains inconclusive. We aimed to analyze the effect of a cross connector in a finite element model (FE model). Study Design: A FE model of the L1-L5 spine segment with pelvis and a spinopelvic stabilization was reconstructed from patient-specific CT images. The biomechanical relevance of a cross connector in a Denis zone I (AO: 61-B2) sacrum fracture was assessed in the FE model by applying bending and twisting forces with and without a cross connector. Biomechanical outcomes from the numerical model were investigated also considering uncertainties in material properties and levels of osseointegration. Results: The designed FE model showed comparable values in range-of-motion (ROM) and stresses with reference to the literature. The superiority of the spinopelvic stabilization (L5/Os ilium) ± cross connector compared to a non-operative procedure was confirmed in all analyzed loading conditions by reduced ROM and principal stresses in the disk L5/S1, vertebral body L5 and the fracture area. By considering the combination of all loading cases, the presence of a cross connector reduced the maximum stresses in the fracture area of around 10%. This difference has been statistically validated (p < 0.0001). Conclusion: The implementation of a spinopelvic stabilization (L5/Os ilium) in sacrum fractures sustained the fracture and led to enhanced biomechanical properties compared to a non-reductive procedure. While the additional cross connector did not alter the resulting ROM in L4/L5 or L5/sacrum, the reduction of the maximum stresses in the fracture area was significant.

Biomechanical Comparison of Five Fixation Techniques for Unstable Fragility Fractures of the Pelvic Ring

Background: Incidence of pelvic ring fractures has increased over the past four decades, especially after low-impact trauma—classified as fragility fractures of the pelvis (FFP). To date, there is a lack of biomechanical evidence for the superiority of one existing fixation technique over another. An FFP type IIc was simulated in 50 artificial pelvises, assigned to 5 study groups: Sacroiliac (SI) screw, SI screw plus supra-acetabular external fixator, SI screw plus plate, SI screw plus retrograde transpubic screw, or S1/S2 ala–ilium screws. The specimens were tested under progressively increasing cyclic loading. Axial stiffness and cycles to failure were analysed. Displacement at the fracture sites was evaluated, having been continuously captured via motion tracking. Results: Fixation with SI screw plus plate and SI screw plus retrograde transpubic screw led to higher stability than the other tested techniques. The S1/S2 ala–ilium screws were more stable than the SI screw or the SI screw plus external fixator. Conclusions: In cases with displaced fractures, open reduction and plate fixation provides the highest stability, whereas in cases where minimally invasive techniques are applicable, a retrograde transpubic screw or S1/S2 ala–ilium screws can be considered as successful alternative treatment options.

Surgical Wound Complications After Percutaneous Posterior Pelvic Ring Fixation in Patients Who Undergo Pelvic Arterial Embolization

OBJECTIVE

To report on the incidence of surgical wound complications after percutaneous posterior pelvic ring fixation in patients who have also undergone pelvic arterial embolization (PAE) and determine whether the risks outweigh the benefits.

DESIGN

Retrospective cohort study.

SETTING

Academic level 1 trauma center.

PATIENTS

Two hundred one consecutive patients who underwent percutaneous posterior pelvic fixation at our institution were included in this study. Of these, 27 patients underwent pelvic arterial embolization.

INTERVENTION

Percutaneous posterior pelvic fixation and pelvic arterial embolization.

MAIN OUTCOME MEASUREMENTS

Charts were reviewed for posterior percutaneous surgical wound complications including infection, dehiscence, seroma, tissue necrosis, and return to OR for debridement in all patients.

RESULTS

Of the 27 patients who received PAE, none developed posterior surgical wound complications. Of those who did not receive PAE, there was one posterior surgical wound complication documented. There were no cases of wound infection in either group.

CONCLUSION

Pelvic arterial embolization can be a valuable intervention in treating hemodynamically unstable patients with pelvic ring injuries. Although even selective pelvic arterial embolization is not entirely benign, there seems to be minimal risk of wound complications when percutaneous posterior pelvic ring fixation is performed.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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

BACKGROUND

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.

HYPOTHESIS

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.

MATERIALS AND METHODS

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.

RESULTS

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 ≥ 10 mm) 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 ≥ 10 mm at S1, 52% vs 67% (p = 0.001), and at S2, 64% vs 86% (p < 0.001).

DISCUSSION

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 ≥ 10 mm and the resulting increase in angular tolerance for safe passage of a transilioscral screw.

LEVEL OF EVIDENCE IV

Level Retrospective Cohort.

Two-Dimensional Visualization of the Three-Dimensional Planned Sacroiliac Screw Corridor with the Slice Fusion Method

Insertion of sacro-iliac (SI) screws for stabilization of the posterior pelvic ring without intraoperative navigation or three-dimensional imaging can be challenging. The aim of this study was to develop a simple method to visualize the ideal SI screw corridor, on lateral two-dimensional images, corresponding to the lateral fluoroscopic view, used intraoperatively while screw insertion, to prevent neurovascular injury. We used multiplanar reconstructions of pre- and postoperative computed tomography scans (CT) to determine the position of the SI corridor. Then, we processed the dataset into a lateral two-dimensional slice fusion image (SFI) matching head and tip of the screw. Comparison of the preoperative SFI planning and the screw position in the postoperative SFI showed reproducible results. In conclusion, the slice fusion method is a simple technique for translation of three-dimensional planned SI screw positioning into a two-dimensional strict lateral fluoroscopic-like view.

Do Fully Threaded Transiliac-Transsacral Screws Improve Mechanical Stability of Vertically Unstable Pelvic Fractures? A Cadaveric Biomechanical Analysis

OBJECTIVE

To determine whether fully threaded transiliac-transsacral (TI-TS) fixation is biomechanically superior to partially threaded TI-TS fixation of vertically unstable transforaminal sacral fractures.

METHODS

Vertically unstable zone 2 sacral fractures were created in 20 human cadaveric pelves with a unilateral osteotomy and resection of 1 cm of bone through the foramen of the sacrum to represent comminution. Ten specimens received either 2 7.3-mm fully threaded or 2 7.3-mm partially threaded TI-TS screw fixation at the S1 and S2 body, and every specimen received standard 3.5-mm 8-hole parasymphyseal plating anteriorly. Each pelvis was loaded to 250 N at 3 Hz for 100,000 cycles and then loaded to failure. The primary outcome was fracture displacement at the S1 foramen, which was measured at 25,000, 50,000, 75,000, and 100,000 cycles. Secondary outcomes were simulated clinical failure of ≥1 cm displacement at the S1 foramen to determine occurrence probability of failure, and load at failure was defined as 2.5 cm of the linear loading system displacement. Specimens in the fully threaded and partially threaded cohorts were otherwise respectively comparable in regards to age, gender, and bone density.

RESULTS

Five of the 10 TI-TS partially threaded specimens experienced simulated clinical failure with >1 cm displacement at the S1 foramen compared with 0 of the 10 TI-TS fully threaded cohort (50% vs. 0%, P = 0.03). The mean maximal displacement at the S1 foramen was greater in the partially threaded cohort (9.3 mm) compared with the fully threaded cohort (3.6 mm; P = 0.004). Fully threaded specimens also demonstrated greater mean force to failure than the partially threaded specimens (461 N vs. 288 N; P = 0.0001).

CONCLUSIONS

Fully threaded TI-TS screw fixation seems to be mechanically superior to partially threaded fixation in a cadaveric vertically unstable transforaminal sacral fracture model with significantly less displacement of the posterior pelvic ring and greater load to failure.

Posterior Stabilization of Unstable Sacral Fractures: A Single-Center Experience of Percutaneous Sacroiliac Screw and Lumbopelvic Fixation in 67 Cases

Study Design

This is a retrospective study.

Purpose

Recent advances in intraoperative imaging and closed reduction techniques have led to a shifting trend toward surgical management in every unstable sacral fracture. This study aimed to evaluate the clinicoradiological outcome of the sacroiliac (SI) screw and lumbopelvic fixation (LPF) techniques and thereby delineate the indications for each.

Overview of Literature

Optimal management guidelines for unstable sacral fractures are still lacking probably due to the rarity of these injuries and varying fixation trends.

Methods

Out of the 67 patients, 40 and 27 were in the SI and LPF groups, respectively. The electronic medical record for each patient was reviewed, including patient demographic data, mode of trauma, coexisting injuries, neurological status (Gibbon's four-grade system), Injury Severity Score, time from admission to operative stabilization, type of surgical stabilization, complications, return to the operating room, and treatment outcome measures using Majeed's functional grading system and Matta's radiological criteria. The minimum follow-up period was 2 years.

Results

Noncomminuted longitudinal injuries with normal neurology and acceptable closed reduction have undergone SI screw fixation (n=40). Irreducible, comminuted, or high transverse fractures associated with dysmorphic anatomy or neurodeficit were managed by LPF (n=27). Excellent and good Majeed and Matta scores at 86.57% and 92.54% of the patients, respectively, were postoperatively achieved.

Conclusions

Unstable sacral fractures can be effectively managed with percutaneous SI screw including vertically unstable injuries by paying strict attention to preoperative patient selection whereas LPF can be reserved for comminuted fractures, unacceptable closed reduction, associated neurodeficit, lumbosacral dysmorphism, and high transverse fractures.

Temporary External Fixation to Table as a Traction Reduction Aide in the Treatment of Unstable Pelvic Ring Injuries: A Technical Note

Displaced pelvic ring injuries can be challenging to even the experienced orthopedic traumatologist. A temporary external fixation to table construct provides a quick, simple, and accessible means of external skeletal fixation to reliably obtain and maintain stable hemipelvis reduction on the operating room table. The contralateral hemipelvis can be stabilized to the table by use of Steinman pins safely inserted into the subtrochanteric and anterior column regions and later connected to external fixator bars attached to the table. With rigid stabilization, the displaced contralateral pelvic fragment(s) can be reduced in a more vector intentional manner with greater force than the traditional means of pelvic reduction can allow. The skeletal-table fixation technique is presented along with two cases, a combined pelvic-acetabular injury and an isolated pelvic ring injury.

Radiostereometric Analysis Allows Assessment of the Stability and Inducible Displacement of Pelvic Ring Disruptions during Healing: A Case Series

There is currently no accurate data on fracture displacement during the rehabilitation of pelvic ring injuries. This study investigated the use of radiostereometric analysis (RSA) in assessing the stability of C1 pelvic ring injuries stabilised with a posterior plate and an anterior external fixator. Six patients, instructed to weight-bear as tolerated after surgery, were reviewed at 2, 4, 6, 12, 26, 52 and 104 weeks. The external fixators were removed at 6 weeks. Outcomes, including the Iowa Pelvic Score (IPS), and complications were recorded. Fracture stability was assessed using measurements on plain radiographs and RSA. All patients progressed to full weight-bearing without support within 6 weeks. At 104 weeks, the IPS was excellent in four patients, good in one patient and fair in one patient. Plain radiographs showed that all fractures were well reduced, and no loss of reduction occurred over time. By contrast, RSA measurements identified displacement in all cases. The maximum three-dimensional (3D) displacement at any time point in each patient ranged from 2 to 10 mm. Two patients with the largest displacement over time had the lowest IPS. RSA also demonstrated displacements above the currently defined normal threshold through the ‘un-injured’ sacroiliac joint in the same two patients, suggesting a subtle C2 injury, missed at initial assessment. This study demonstrates the limitations of plain radiographs in assessing pelvic fracture stability and displacement during healing, and the potential of RSA to monitor more accurately the effects of stabilisation and weight-bearing on fracture stability.

Posterior pelvic ring bone density with implications for percutaneous screw fixation

BACKGROUND

Although the second (S2) and third (S3) sacral segments have been established as potential osseous fixation pathways for screw fixation, the S2 body has been demonstrated to have inferior bone density when compared to the body of the first (S1) sacral segment. Caution regarding the use of iliosacral screws at this level has been advised as a result. As transiliac-transsacral screws traverse the lateral cortices of the posterior pelvis, they may be relying on bone with superior density for purchase, which could obviate this concern. The objective of this study was to compare the bone density of the posterior ilium and sacroiliac joint to that of the sacral body at the first (S1), second (S2), and third (S3) sacral levels.

MATERIALS AND METHODS

A retrospective case series was performed, reviewing the CT scans of 100 patients without prior pelvic trauma. Each CT was confirmed to have available osseous fixation pathways at the first (S1), second (S2), and third (S3) sacral segments. The bone density of the posterior ilium/sacroiliac joint (PISJ) and sacral body (SB) was measured using the embedded standardized Hounsfield units (HU) tool at each sacral level.

RESULTS

The average S2 PISJ bone density (320.1) was significantly higher than the S1 (286.5) and S3 (278.9) PISJ (p < 0.0001) and S1 and S3 PISJ was not statistically different. The S1 sacral body bone density (231.1) was significantly higher than the S2 (182.1) and S3 (126.8) bone density (p < 0.0001). The PISJ bone density is greater than the sacral body at every sacral level (p < 0.0001).

CONCLUSION

The S2 PISJ bone density is significantly greater than S1. The S1, S2, and S3 PISJ bone density is greater than the sacral body at all sacral levels, and the S1 body has higher bone density than the S2 and S3 bodies. These differences in bone density may have implications for the stability of posterior pelvic ring fixation constructs with regard to screw purchase.

LEVEL OF EVIDENCE

Level III-Case cohort series.

Vertical shear pelvic ring injuries: do transsacral screws prevent fixation failure?

OBJECTIVES

To determine the frequency of fixation failure after transsacral-transiliac (TS) screw fixation of vertical shear (VS) pelvic ring injuries (OTA/AO 61C1) and to describe the mechanism of failure of TS screws.

DESIGN

Retrospective cohort study.

SETTING

Level 1 academic trauma center.

PATIENTS/PARTICIPANTS

Twenty skeletally mature patients with unilateral, displaced, unequivocal VS injuries were identified between May 1, 2009 and April 31, 2016. Mean age was 31 years and mean follow-up was 14 months. Twelve had sacroiliac dislocations (61C1.2) and eight had vertical sacral fractures (61C1.3).

INTERVENTION

Operative treatment with at least one TS screw.

MAIN OUTCOME MEASUREMENTS

Radiographic failure, defined as a change of >1 cm of combined displacement of the posterior pelvis compared with the intraoperative position on inlet and outlet radiographs.

RESULTS

Radiographic failure occurred in 4 of 8 (50%) vertical sacral fractures. Posterior fixation was comprised of a single TS screw in 3 of these 4 failures. The dominant mechanism of screw failure was bending. All of these failures occurred early in the postoperative period. No fixation failures occurred among the sacroiliac dislocations. There were no deep infections or nonunions.

CONCLUSIONS

This is the first study to describe the mechanism of failure of TS screws in a clinical setting after VS pelvic injuries. We caution surgeons from relying on single TS screw fixation for vertically unstable sacral fractures. Close radiographic monitoring in the first few weeks after surgery is advised.

LEVEL OF EVIDENCE

Level IV.

Assessment of osseous corridor for transiliac-transsacral screws and clinical applications: Computational simulation study

BACKGROUND

Transiliac-transsacral (TITS) screw fixation might be necessary in some cases involving the vertical shearing injuries with transforaminal fracture and bilateral posterior ring injuries. However, the possibility of S₁ TITS screw should be preoperatively assessed because the pelvic ring injuries with sacral dysmorphism had the insufficient osseous corridors.

HYPOTHESIS

AxW_S2 may predict the possibility of TITS screw fixation and be used as the new indicator to discriminate the sacral dysmorphism.

MATERIALS & METHODS

The conventional CT images of eighty-two cadaveric pelvis imported into Mimics® software to reconstruct three-dimensional (3D) models. A 7.0 mm-sized screw was processed into a 3D model using a 3D-sensor at actual size and virtually implanted as S₁ and S₂ TITS screw using Mimics® software. The cortical violation around screw path was evaluated using 3D biplanar and conventional CT images. The osseous corridor widths around TITS screws were measured in the axial plane images and defined as AxW_S1 and AxW_S2, respectively.

RESULTS

Despite no cortical violation in S₂ of all models, cortical violation of S₁ TITS screw was found in 20 models. Of them, 14 models (impossible models) were identified in the 3D biplanar images, and all 20 models (CT-violation models) were identified only in CT axial plane images. AxWS₁ was<7mm in the impossible models and<9.0mm in the CT-violation models. AxW_S2 negatively correlated with AxW_S1 (R -0.450, p<0.01). By receiver operating characteristic curve analysis to identify the CT-violation model using AxW_S2, the cut-off value of AxW_S2 was 13.32mm (sensitivity 0.70, specificity 0.70).

DISCUSSION

By using AxW_S2, the possibility of S₁ TITS screw fixation could be predicted and safely placed without cortical violation, if AxW_S2 was less than 13mm. Considering the negative relationship with AxW_S1, AxW_S2 should be used as a new indicator to predict safe S₁ TITS screw fixation.

LEVEL OF EVIDENCE

III, controlled laboratory study.

Subacute Minimally Invasive Decompression of L5 and S1 Nerve Roots for Neurologic Deficit After Fixation of Unstable Pelvic Fracture: A Case Report and Review of the Literature

CASE

A 73-year-old man experienced immediate neurological decline after percutaneous transsacral screw fixation for a pelvic ring injury sustained after a 25-foot fall. Workup revealed well-positioned screws and compression of the right L5 and S1 nerve roots at the fracture site. Symptoms improved after direct decompression without screw revision.

CONCLUSION

The courses of the L5 and S1 nerve roots place them at risk of compression within the fracture during transsacral screw fixation. In highly comminuted fractures, avoidance of compression screws or use of intraoperative CT might prevent this complication. Direct nerve root decompression alone can be a successful treatment.

Bone density of first and second segments of normal and dysmorphic sacra

Background

Iliosacral screw fixation is safe and effective but can be complicated by loss of fixation, particularly in patients with osteopenic bone. Sacral morphology dictates where iliosacral screws may be placed when stabilizing pelvic ring injuries. In dysmorphic sacra, the safe osseous corridor of the upper sacral segment (S1) is smaller and lacks a transsacral corridor, increasing the need for fixation in the second sacral segment (S2). Previous evidence suggests that S2 is less dense than S1. The aim of this cross-sectional study is to further evaluate bone mineral density (BMD) of the S1 and S2 iliosacral osseous pathways through morphology stratification into normal and dysmorphic sacra.

Materials and methods

Pelvic computed tomography scans of 50 consecutive trauma patients, aged 18 to 50 years, from a level 1 trauma center were analyzed prospectively. Five radiographic features (upper sacral segment not recessed in the pelvis, mammillary bodies, acute alar slope, residual S1 disk, and misshapen sacral foramen) were used to identify dysmorphic characteristics, and sacra with four or five features were classified as dysmorphic. Hounsfield unit values were used to estimate the regional BMD of S1 and S2. Student’s t-test was utilized to compare the mean values at each segment, with statistical significance being set at p < 0.05. No change in clinical management occurred as a result of inclusion in this study.

Results

A statistical difference in BMD was appreciated between S1 and S2 in both normal and dysmorphic sacra (p < 0.0001), with 28.4% lower density in S2 than S1. Further, S1 in dysmorphic sacra tended to be 4% less dense than S1 in normal sacra (p = 0.047). No difference in density was appreciated at S2 based on morphology.

Conclusions

Our results would indicate that, based on BMD alone, fixation should be maximized in S1 prior to fixation in S2. In cases where S2 fixation is required, we recommend that transsacral fixation should be strongly considered if possible to bypass the S2 body and achieve fixation in the cortical bone of the ilium and sacrum.

Level of evidence

Level III.

Posterior pelvic ring injury of straddle fractures: Incidence, fixation methods, and clinical outcomes

Straddle fracture, a superior and inferior ramus fracture of both sides, is generally treated conservatively. However, posterior pelvic ring injury is often associated with straddle fracture, leading to unstable pelvic bone fracture that requires surgical treatment. The present study reports the clinical and radiological outcomes of straddle fracture with posterior pelvic ring injury. This study included 73 patients (41 men, 32 women) with a straddle fracture injury. The injury mechanism, injury severity score (ISS), accompanying injuries, presence of posterior pelvic ring injury, and fixation methods for the pelvic fracture were analyzed, and outcomes were evaluated functionally and radiologically. Of the 73 patients, 56 (77%) had a posterior pelvic ring injury and 7 died. In 43 patients, the posterior pelvic ring injuries constituted unstable pelvic injury and were treated surgically. The fixation method was determined based on the severity of the posterior pelvic injury. The patients' mean ISS was 24.7 points. Radiological evaluation of surgical outcomes in 43 patients revealed the outcomes as anatomic in 20, nearly anatomic in 14, moderate in 5, and poor in 4, whereas functional evaluation revealed the outcomes as excellent in 21, good in 9, fair in 7, and poor in 6. Posterior pelvic ring fracture can accompany straddle fractures, which may lead to pelvic injury instability. Thus, special attention is required for patients with a straddle fracture.

Safety and efficacy of 2D-fluoroscopy-based iliosacral screw osteosynthesis: results of a retrospective monocentric study

Introduction

Iliosacral screw osteosynthesis is a well-accepted procedure for stabilization of sacral fractures and iliosacral (fracture) dislocations.

Materials and Methods

In this monocentric study, safety and efficacy of conventional 2D-fluoroscopic-guided iliosacral screw insertion were evaluated.

Results

During a 10-year period (2005–2014), 98 patients between the age of 18 and 65 years received 207 iliosacral screws in 101 procedures. Average patient age was 43.2 years. There were 46 Type B and 40 Type C injuries in the AO/OTA classification, nine patients had a fragility fracture of the pelvis. In three patients, primary radiological data were missing. The indication for surgical treatment was a sacral fracture in 97 patients, a pure iliosacral dislocation in 37 patients and a fracture-dislocation in 31 patients. 70 procedures were performed with the patient in supine position, 31 with the patient in prone position. Surgery was done in a minimal-invasive technique in 76 patients, in 22 patients an open reduction was necessary before screw insertion. 81 patients received a unilateral, 17 patients a bilateral screw osteosynthesis. 199 screws were inserted in S1, only eight screws in S2. 65 patients received two screws unilaterally, ten patients two screws bilaterally. There were no vascular or neurologic complications. During in-hospital stay, there were seven complications, which needed 12 operative revisions: three wound infections, two hematomas, one screw malalignment and one early screw loosening. In 28 patients with 56 iliosacral screws, a pelvic CT-scan was performed during follow-up. A penetration of a cortical layer was diagnosed in 20 of these screws. All penetrations were seen in double screw osteosynthesis of S1. In none of the patients, complaints could be explained by the malalignment of these screws. Five operative revisions were performed during follow-up: two for screw loosening, two for fracture healing problems and one for screw malalignment. Metal removal was performed in 39 patients with 75 screws. 2D-fluoroscopic-guided iliosacral screw osteosynthesis is a safe and efficient procedure in clinical practice.

Discussion

A thorough preoperative evaluation of the morphology of the upper sacrum and careful operative procedure are indispensable. Fluoroscopic views in AP, lateral, inlet and outlet must allow recognition of all anatomical landmarks. The indication for double screw osteosynthesis in S1 should be taken with caution. Screw malalignments do not inevitably correlate with complaints.

Gender-Associated Differences in Sacral Morphology Do Not Affect Feasibility Rates of Transsacral Screw Insertion. Radioanatomic Investigation Based on Pelvic Cross-sectional Imaging of 200 Individuals

STUDY DESIGN

Retrospective radioanatomic single-center cohort study.

OBJECTIVE

To investigate sex-specific differences in transsacral corridor dimensions, determine feasibility rates of transsacral screw placement without extended safety zones around planned screw positions, and develop an index defining sacral dysmorphism (SD) irrespective of transsacral corridor diameters.

SUMMARY OF BACKGROUND DATA

Previously reported SD definitions used radiologically identifiable pelvic characteristics or predefined minimum diameter thresholds of transsacral corridors in the upper sacral segment including safety zones for screw placement. Technical progress of surgical 3D image guidance improved sacral screw insertion accuracy questioning established minimum diameter threshold-based SD definitions.

METHODS

Datasets from cross-sectional pelvic imaging of 100 women and 100 men presenting to a general hospital from July 2018 through August 2018 were included in a database to evaluate transsacral trajectory rates, and dimensions of transsacral corridor lengths, widths (TSCWs), and heights (TSCHs) in sacral segments I to III (S1-3). SD was assumed, if no transsacral trajectory was found in S1 with a corridor diameter of at least 7.5 mm.

RESULTS

Women presented significantly higher rates of transsacral trajectories in the inferior sector of S1 (P = 0.03), and larger transsacral corridor lengths in S2 (superior sector, P = 0.045), and S3 (central position, P = 0.02). In men, significantly higher feasibility rates were found for the placement of two transsacral screws in S2 (P = 0.0002), and singular screws in S3 (P = 0.006), with larger S1- (P = 0.0002), and central S2-TSCWs (P = 0.006). SD was prevalent in 17% of women, and 16% of men (P = 0.85). Calculating TSCW ratios of S1 and S2 was significantly indicative for SD at values below a threshold of 0.8 in women (P < 0.00001), and men (P = 0.0004).

CONCLUSION

SD is independent of sex despite significant differences in sacral morphology. An index defining SD irrespective of absolute transsacral corridor dimensions is presented to reliably differentiate dysmorphic from nondysmorphic sacra in women and men.

LEVEL OF EVIDENCE

2.

Results of open reduction internal fixation versus percutaneous iliosacral screw fixation for unstable pelvic ring injuries: retrospective study of 36 patients

INTRODUCTION

Surgical stabilization of posterior pelvic ring fractures can be achieved by closed reduction and percutaneous fixation (CRPF) or by open reduction and internal fixation (ORIF). The aim of the present study is to compare the clinical results of both methods.

MATERIAL AND METHODS

Medical records of 36 patients consecutively operated for unstable pelvic ring injuries were retrospectively reviewed. We compared 22 patients treated with CRPF versus 14 patients stabilized by using ORIF between 2007 and 2017. The Majeed and Pohlemann scores were used to evaluate postoperative functional outcomes. Complications like blood loss, infection rate, Neurological injury, the operative time and the length of hospital stay were analyzed.

RESULTS

The median Majeed pelvic score was 87 points for the CRPF technique compared with 69 points for the ORIF technique. The median Pohlemann score, operative time and length of hospitalization were similar between the two groups. The median blood loss for the CRPF technique was 300 ml compared to 500 ml for the ORIF technique. CRPF and ORIF procedure had each one neurological lesion. There was one case of infection in the ORIF group and none in the CRPF group. No measurements except for the blood loss have reached the significance threshold.

CONCLUSION

The CRPF technique shows a clear decrease in blood loss. There was no statistically significant difference in the functional results, infection rate, neurological injury, operative time and hospital stay between both techniques.