Anterior Pelvic Ring: Introduction to Evaluation and Management

Comparison of ESIN and other minimally invasive techniques for anterior pelvic ring injury: a finite element analysis and case-control study

OBJECT

A novel technique, percutaneous elastic stable intramedullary nail fixation (ESIN), proposed by our team for the treatment of anterior pelvic ring injury. Finite element analysis and retrospective case-control study were used to compare biomechanical properties and clinical outcomes between ESIN and other techniques.

METHODS

Four groups of finite element models of pelvic anterior ring injury were simulated, including ESIN (model A), retrograde transpubic screw fixation (RTSF, model B), subcutaneous internal fixator (model C), and external fixator (model D), and a vertical downward load of 500 N was applied to the S1 vertebral endplate. Stress and displacement distributions of intact pelvis, displacement distributions of pubic fracture fragments, and stress distributions of fixation devices were analysed. Then 31 patients with anterior pelvic ring injury (15 in the ESIN group and 16 in the RTSF group) were reviewed. Clinical outcomes were evaluated at the final follow-up. Postoperative complications were also recorded.

RESULTS

Under 500N loading, the intact stability of the pelvis was compared as follows: model B (20.58 mm, 121.82 MPa), model A (20.80 mm, 129.97 MPa), model C (22.02 mm, 141.70 MPa), and model D (22.57 mm, 147.06 MPa). The regional stability of superior pubic ramus was compared as follows: model B (9.48 mm), model A (10.16 mm), model C (10.52 mm), and model D (10.76 mm). All 31 patients received follow-up at least 12 months postsurgery (range 12-20 months). Age, sex, injury mechanism, fracture type, time between the injury and operation, American Society of Anesthesiologists score, intraoperative blood loss, hospital stay, follow-up period, time to union, and Majeed scores did not differ significantly between the two groups ( P >0.05). However, the differences in the duration of unilateral surgery, unilateral intraoperative fluoroscopy and one-time success rate were significant ( P <0.05).

CONCLUSIONS

With sufficient biomechanical stability and minimally invasive advantage, the percutaneous technique using ESIN can be used to successfully treat anterior pelvic ring injuries. In addition, advantages over RTSF include a shorter duration of surgery, reduced requirement for intraoperative fluoroscopy, and a higher one-time success rate. ESIN therefore constitutes a good alternative to RTSF.

Comparison of the two surgery methods combined with accelerated rehabilitation in the treatment of lateral compression type 1 pelvic fractures in the elderly

BACKGROUND

Treating lateral compression type 1 (LC1) pelvic ring injuries in older patients is controversial. This study evaluated surgical treatments combined with ERAS for treating LC1 pelvic fractures in the elderly.

METHODS

In this retrospective study, patients who underwent surgery with INFIX (supra-acetabular spinal pedicle screws, and a subcutaneous connecting rod; the experimental group) or superior pubic ramus cannulated screw (the control group) fixation of LC1 pelvic fracture from January 2019 to January 2022 were reviewed. Injury radiography and computed tomography were performed to determine the Young-Burgess classification. All patients performed standardized early rehabilitation exercises after surgery and were followed up for > 12 months. After surgery, the Matta score and the visual analog scale (VAS) were evaluated, and the postoperative weight-bearing time and the length of stay (LOS) were recorded. The Barthel index and the Majeed score were evaluated at 4 months after surgery and at the last follow-up.

RESULTS

Fifty-three patients were included. Thirty-two patients included in the experimental group had a mean age of 75.0 ± 6.2 (range, 66-86) years, and the other 21 patients in the control group had a mean age of 74.6 ± 4.6 (range, 68-83) years. The mean follow-up time was 13.1 ± 1.6 (range, 12-18) months in the experimental group and 13.4 ± 1.3 (range, 12-16) months in the control group. There were no significant differences in follow-up time between the groups (P > 0.05). The mean VAS score, time to weight-bearing, and LOS were 2.0 ± 0.7 (range, 1-3), 1.1 ± 0.3 (range, 1-2) d, and 5.8 ± 0.9 (range, 4-7) d in the experimental group and 2.3 ± 1.2 (range, 1-5), 2.5 ± 1.6 (range, 1-7) d, and 6.1 ± 1.6 (range, 5-11) d in the control group, respectively. Between the two groups, there was a significant difference in the postoperative time to weight-bearing (P < 0.05), while there was no significant difference in the LOS (P > 0.05). No bedrest-related complications occurred in either group. The Matta score was 90.6% in the experimental group and 90.4% in the control group (P > 0.05). At the 4-months follow-up, the experimental group had a better Barthel index and Majeed score compared with the control group, which were 86.1 ± 6.2 (range, 70-95) vs. 81.2 ± 4.1 (range, 75-90) and 86.3 ± 3.3 (range, 78-91) vs. 80.3 ± 3.9 (range, 76-86), respectively. The experimental group had better early rehabilitation effect than the control group. There was no significant difference in Barthel index and Majeed score between the two groups at the last follow-up (P > 0.05).

CONCLUSION

Both INFIX and intramedullary superior pubic ramus cannulated screws can successfully treat LC1 pelvic fractures and reduce bed rest complications among older patients.

FFP: Indication for minimally invasive navigation technique

An 85-year-old female patient was transferred to our clinic for surgical treatment of a complex FFP IIc. She had suffered a ground level fall 10 days ago and was still living independently. The patient was initially treated conservatively with pain medication and immobilization in an outward hospital. Due to the clinical symptoms and complex fracture pattern a physiotherapeutic assisted mobilization was not possible. The clinical examination revealed severe bilateral pain at the anterior and posterior pelvic ring. We performed a minimally invasive and an image-guided surgical stabilization. After surgical treatment the patient was mobilized with crutches for short distances. On the third day after surgical intervention the patient was discharged from our hospital into rehabilitation. This case shows the successful use of minimally invasive and modern navigation technique for treatment of a complex FFP.

A biomechanical comparison of superior ramus plating versus intramedullary screw fixation for unstable lateral compression pelvic ring injuries,,

INTRODUCTION

Management of the anterior component of unstable lateral compression (LC) pelvic ring injuries remains controversial. Common internal fixation options include plating and superior pubic ramus screws. These constructs have been evaluated in anterior-posterior compression (APC) fracture patterns, but no study has compared the two for unstable LC patterns, which is the purpose of this study.

METHODS

A rotationally unstable LC pelvic ring injury was modeled in 10 fresh frozen cadaver specimens by creating a complete sacral fracture, disruption of posterior ligaments, and ipsilateral superior and inferior rami osteotomies. All specimens were repaired posteriorly with two fully threaded 7 mm cannulated transiliac-transsacral screws through the S1 and S2 corridors. The superior ramus was repaired with either a 3.5 mm pelvic reconstruction plate (n = 5) or a bicortical 5.5 mm cannulated retrograde superior ramus screw (n = 5). Specimens were loaded axially in single leg support for 1000 cycles at 400 N followed by an additional 3 cycles at 800 N. Displacement and angulation of the superior and inferior rami osteotomies were measured with a three-dimensional (3D) motion tracker. The two fixation methods were then compared with Mann-Whitney U-Tests.

RESULTS

Retrograde superior ramus screw fixation had lower average displacement and angulation than plate fixation in all categories, with the motion at the inferior ramus at 800 N of loading showing a statistically significant difference in angulation.

CONCLUSION

Although management of the anterior ring in unstable LC injuries remains controversial, indications for fixation are becoming more defined over time. In this study, the 5.5 mm cannulated retrograde superior ramus screw significantly outperformed the 3.5 mm reconstruction plate in angulation of the inferior ramus fracture at 800 N. No other significance was found, however the ramus screw demonstrated lower average displacements and angulations in all categories for both the inferior and superior ramus fractures.

Three-dimensional navigation-guided percutaneous trans-symphyseal screw for mechanically unstable pubic symphysis diastasis

Minimally invasive trans-symphyseal screw (TSS) for pubic symphysis diastasis was recently advocated, and its feasibility and reproducibility under 3D-navigation guidance are explored. Fifteen cases between 2016 and 2021 with a background of pubic symphysis diastasis are reviewed in this case series. Twenty-two TSS were inserted with an average Injury Severity Score of 35.3. Sixty percent received a one-stage procedure including fracture reduction, intra-operative 3D imaging, and planning followed by execution. The mean operative time and blood loss were 132 minutes and 160 ml, respectively. Average fracture healing was 5.8 months with two delayed unions at 9 months. The pubic symphysis distance was maintained in all cases at 6 months post-op. The average Marjeed score, Multicenter Study Group Pelvic Outcome Score, and Numeric pain rating scale were 60.2, 6.5, and 2.7, respectively. We conclude that 3D-navigation-guided percutaneous TSS restores pelvic stability and provides satisfactory pain control, and thus a safe and effective alternative to open reduction internal fixation.

Iliosacral screw fixation of pelvic ring disruption with tridimensional patient-specific template guidance

INTRODUCTION

Posterior pelvic ring disruption includes sacral fractures, sacroiliac joint fracture dislocations and ilium fractures. Percutaneous iliosacral screw fixation of sacral fractures and sacraoiliac joint fracture dislocations have been prevailing, it has the advantages of minimal invasiveness, less blood loss and low wound infection rate.

HYPOTHESIS

This study was to evaluate the application of three-dimensional (3D) printed patient-specific guide template in closed reduction and iliosacral screw fixation of posterior pelvic ring disruption.

MATERIAL AND METHODS

The data of patients, who were treated with closed reduction and iliosacral screw fixation of posterior pelvic ring disruption with the assistance of 3D printed guide template from December 2014 to September 2018, were collected. The screw placement time, fluoroscopy time, intraoperative blood loss, fracture reduction, screw position, and functional assessment were recorded.

RESULTS

There were 17 cases of unstable pelvic fractures,and 20 screws were inserted for fixation of sacral fractures or sacroiliac joint dislocations, with bilateral screw placement in 3 cases. The average time for each screw placement was 45.9±8.6min (30-60min). The average fluoroscopy time for each screw insertion was 50.3±19.7s (24-96 s). The mean blood loss for each screw placement was 32.0±11.1ml (20-50ml). According to Matta scale, the fracture reduction was graded as excellent in all the 17 cases. According to the modified Gras classification, the 3D CT reconstruction of the pelvis demonstrated Grade 1 for 18 screws and Grade 2 for 2 screw. Functional outcome 1 year postoperatively was rated as 15 excellent and 2 good, according to the Majeed functional scale.

DISCUSSION

It is feasible and safe to stabilize the posterior pelvic ring disruption using iliosacral screw fixation under assistance of the 3D printed guide template. It could reduce fluoroscopy time, screw placement time and intraoperative blood loss and achieve good postoperative recovery.

LEVEL OF PROOF

IV; Retrospective study.

Danger zone - The spermatic cord during anterior plating of the symphysis pubis

BACKGROUND

Distances between anatomic landmarks and anatomic structures at risk are often underestimated by surgeons.

PURPOSE

The goal of the study was to evaluate the distances between anatomic landmarks and the spermatic cord in case of anterior plating of the symphysis.

METHODS

A total of 25 pelves (50 hemipelves) of male embalmed cadavers were dissected. A 5-hole 3.5mm locking compression plate (Synthes GmbH) was fixed from directly anterior on the symphysis. Measurements were taken 1) distance between the tips of both pubic tubercles, 2) horizontal interval between the lateral border of the plate and the medial margin of the SC (bilateral), 3) distances between the medial border of the SC and the tip of the pubic tubercle (bilateral), 4) distances between the medial border of the SC and the lateral basis of the pubic tubercle (bilateral).

RESULTS

The distance between the pubic tubercles was 60.3mm in average (SD: 5.7). The interval between the lateral border of the plate and the medial margin of the SC was on average 4.5mm (SD: 1.9) on the right and 4.7mm (SD: 2.6) on the left side. The distance between the tip of the pubic tubercle and the medial border of the SC was in average 11.2mm (SD: 2.7) on the right, and 11.0mm (SD: 2.7) on the left side. The average distance between the medial border of the SC and the lateral basis of the pubic tubercle was 8.1mm (SD: 2.4) on the right and 8.2 mm (SD: 2.4) on the left side.

CONCLUSION

The SC is at risk not only during dissection but also during anterior plating of the symphysis, because of its close relation to the SC.

CLINICAL RELEVANCE

Average distances between the palpable pubic tubercle and the SC are below one finger breadth (as reference).

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.

The role of anterior supra-acetabular external fixator as definitive treatment for anterior ring fixation in unstable pelvic fractures

PURPOSE

Management of anterior ring injuries is still a matter of discussion, and there are only few studies reporting anterior external fixator as definitive treatment for unstable pelvic injuries. This study aimed to describe the clinical and radiological outcomes of a consecutive series of mechanically unstable pelvic injuries that were treated with definitive anterior supra-acetabular external fixator for the anterior ring, and to identify risk factors for failure.

METHODS

We included a consecutive series of patients with unstable pelvic ring fractures who underwent anterior supra-acetabular external fixation for definitive treatment, between January 2012 and January 2020. All demographics, associated injuries and procedures, injury mechanism, and complications were analysed. Pelvic fracture was classified based on Orthopaedic Trauma Association/Tile AO (OTA/AO) and Young-Burgess classifications. Complications associated with the external fixator were revised. All patients were functionally evaluated at final follow-up and asked to report their clinical outcomes using the Majeed score.

RESULTS

A total of 47 patients were included, of which 25 were females. The median age was 44 years (interquartile range 23-59). Median follow-up duration was 14 months (interquartile range 6-31). The most frequent aetiology was motor vehicle accident (35), followed by fall from height (8). All fractures required posterior pelvic ring fixation. The median time during which patients had external fixation in situ was 11 weeks (interquartile range 9-13). All patients achieved healing of pelvic fracture at median time of 10 weeks (interquartile range 8-12). At final follow-up, the median displacement of the anterior pelvis was 6 mm (interquartile range 0-11). Superficial infection was the most common complication (n = 7). No washout procedures were needed. No major complication was reported. No patient required reoperation for anterior ring fracture. The median Majeed score was 88 points (range 60-95; interquartile range 80-90) at final follow-up.

CONCLUSION

Our findings suggest that the use of supra-acetabular external fixator is safe and effective for definitive treatment of the anterior ring in unstable pelvic fractures. It is a method with high proportion of excellent results, regardless of the type of fracture. The rate of complications is low, and it does not compromise functional results.

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.

Factors Associated With Failure of Superior Pubic Ramus Screws

OBJECTIVE

Examine factors associated with fixation failure in patients treated with superior intramedullary ramus screws.

DESIGN

Retrospective.

SETTING

Single, Level 1 trauma center.

PATIENTS

Unstable pelvic ring fractures amenable fixation that included superior intramedullary ramus screws.

INTERVENTION

Percutaneously inserted intramedullary superior ramus screw fixation of superior pubic ramus (SPR) fractures.

MAIN OUTCOME MEASUREMENTS

Loss of reduction (LOR) of the SPR fracture defined as >2 mm displacement on pelvic radiographs at any time point in follow-up.

RESULTS

Two hundred eighty-five fractures in 211 patients (age 44, 95% confidence interval 40.8%-46.4%, 59.3% women, 55.1% retrograde screws) were included in the analysis. 14 (4.9%) of fractures had LOR. Patients were significantly more likely to have LOR as age increased (P = 0.01), body mass index (BMI) increased (P = 0.01), and if they were women (P < 0.01). There was a significantly decreased LOR (P < 0.01) as fractures moved further from the pubis symphysis. Retrograde screws were significantly (P < 0.01) more likely to have LOR. In SPR fractures treated with retrograde screws, failure was significantly associated with increasing BMI (P = 0.02), the presence of an inferior ramus fracture (P = 0.02), and trended toward significance with increasing age (P = 0.06), and decreased distance from the symphysis (P = 0.07).

CONCLUSIONS

Superior ramus screws are associated with a low failure rate (4.9%), which is lower than previously reported. Retrograde screw insertion, distance from the symphysis, increasing age, increasing BMI, decreased distance from the symphysis, and ipsilateral inferior ramus fractures were predictors of failure. In these patients, alternative modalities should be considered, although low rates of failure can still be expected.

LEVEL OF EVIDENCE

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

Integrity of the pectineal ligament in MRI correlates with radiographic superior pubic ramus fracture displacement

BACKGROUND

Estimating the stability of pelvic lateral compression fractures solely by static radiographs can be difficult. In this context, the role of anterior pelvic soft tissues as potential secondary stabilizer of the pelvic ring has hardly been investigated.

PURPOSE

To correlate the initial radiographic appearance of the pubic ramus fracture with the integrity of the pectineal ligament, a strong ligament along the pecten pubis.

MATERIAL AND METHODS

In total, 31 patients with a pelvic lateral compression fracture (AO/OTA 61- B1.1/B2.1) with 33 superior pubic ramus fractures and available post-traumatic radiographs (pelvis anteroposterior, inlet, outlet) and magnetic resonance imaging (MRI) of the pelvis with fat-suppressed coronal images were reviewed retrospectively. Radiographic superior pubic ramus fracture displacement was measured and correlated to the degree of MR-morphologic alterations of the pectineal ligament (grade 0 = intact, grade 3 = rupture).

RESULTS

In the majority of fractures (72.7%), associated MR-morphologic alterations of the pectineal ligament were present. Radiographic displacement and MRI grading showed a strong positive correlation (Spearman rho = 0.783, P < 0.001). The sensitivity and specificity for a radiographic displacement of >3 mm on plain radiographs to detect a structural ligament lesion on MRI (grade 2 and higher) were 73% and 100%, respectively.

CONCLUSION

Radiographic displacement of superior pubic ramus fractures >3 mm is a strong indicator for a structural lesion of the pectineal ligament. Future studies should investigate the potential biomechanical importance of this ligament for pelvic ring stability.

Preperitoneal Pelvic Packing Is Not Associated With an Increased Risk of Surgical Site Infections After Internal Anterior Pelvic Ring Fixation

OBJECTIVE

To investigate the risk of postoperative surgical site infections after plate fixation of the anterior pelvic ring subsequent to preperitoneal pelvic packing (PPP).

DESIGN

Retrospective observational cohort study.

SETTING

Level I academic trauma center.

PATIENTS

Adult trauma patients with unstable pelvic ring injuries requiring surgical fixation of the anterior pelvic ring.

INTERVENTION

Pelvic plate fixation was performed as a staged procedure after external fixation and PPP/depacking (PPP group; n = 25) or as a single-stage primary internal fixation (control group; n = 87).

MAIN OUTCOME MEASURE

Incidence of postoperative surgical site infections of the pelvic space.

RESULTS

Anterior pelvic plate fixation was performed in 112 patients during a 5-year study period. The PPP group had higher injury severity scores and transfused packed red blood cells than the control group (injury severity score: 46 ± 12.2 vs. 29 ± 1.5; packed red blood cells: 13 ± 10 vs. 5 ± 2; P < 0.05). The mean time until pelvic depacking was 1.7 ± 0.6 days (range: 1-3 days) and 3.4 ± 3.7 days (range: 0-15 days) from depacking until pelvic fracture fixation. Two patients in the PPP group and 8 patients in the control group developed a postoperative infection requiring a surgical revision (8.0% vs. 9.2%; n.s.). Both PPP patients with a pelvic space infection had undergone anterior plate fixation for associated acetabular fractures.

CONCLUSIONS

These data support the safety of the PPP protocol for bleeding pelvic ring injuries due to the lack of increased infection rates after fracture fixation. Caution should be applied when considering PPP in patients with associated acetabular fractures.

LEVEL OF EVIDENCE

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

Posterior tension band plate osteosynthesis for unstable sacral fractures: A preliminary study

INTRODUCTION

Stable reduction and rigid fixation of the sacrum and posterior ring structures are of paramount importance in the management of complex pelvic ring disruptions, Tile B and C. The major concern with the use of conventional methods, like iliosacral screws and iliolumbar fixations is the increased risk for surgical and implant-related morbidity, especially in difficult situations, such as comminuted, bilateral sacral fractures, and fractures in the dysmorphic sacrum. Although various biomechanical studies have reported the posterior trans-iliac plates to provide maximum resistance to distracting forces by the principle of tension band, the literature pertaining to this implication in clinical studies has been limited. The purpose of our study was to assess the efficacy of the trans-iliac plate in the management of unstable sacral fractures and its utility in pelvic disruptions associated with surgical site morbidity.

METHODOLOGY

The patients with unstable pelvic fractures (Tile B and C) between 2013 and 2017 were retrospectively analyzed at a trauma center. First, the anterior ring disruptions were stabilized, and then, the sacral fractures (Denis Zone 1-3) treated by posterior tension band plate osteosynthesis (3.5 mm reconstruction plate) were included. Demographic and perioperative data were assessed. The outcome variables studied were surgical morbidity, pain, loss of reduction, and union and implant-related complications. The outcomes were graded using Lindhal's (radiological) and Majeed (functional assessment) scores.

RESULTS

Thirteen patients (nine male/four female) with a median age of 42 years, had sacral fractures in Denis zones 1/2/3 (four/ten/one, respectively), resulting from Tile pelvic injury B and C were included. The pelvis in five patients was stabilized only with the posterior plate due to the anteriorly-associated surgical site morbidity (Morel-Lavallee lesions and urinary tract injuries). The mean follow-up was 21.5 ± 2.8 months. All fractures had a radiological union by 22 weeks; Lindhal's grade A in ten patients and grade B in three patients. Two out of three patients recovered from preoperative neurological involvement. Two had complained of implant prominence (BMI<19 kg/m²) and there were no implant failures. Four had excellent, six had good, and three had fair or poor functional outcomes.

CONCLUSION

The posterior trans-iliac plate is a minimally invasive and safe procedure that can be used in a wide range of unstable sacral fractures with notably less implant failure rate. The rigid posterior construct restores the principle tension between the iliac blades and minimizes the secondary displacement of the anterior disrupted structures, thereby useful in managing ring disruptions with surgical site morbidity.