Percutaneous fixation of pelvic ring disruptions

Preoperative planning technique for anterior pelvis percutaneous intramedullary screw fixation

Useful techniques have been previously described for the planning of safe transsacral-transiliac screws, but to our knowledge, no straightforward technique has been described for anterior pelvic percutaneous fixation. As this method of anterior ring fixation has demonstrated biomechanical and clinical benefits, we propose a preoperative planning technique for determining the corridor characteristics of the patient's superior pubic ramus/anterior column for fracture fixation with percutaneous intramedullary screws. This technique helps the surgeon assess what diameter of solid or cannulated screw the corridor allows and predict the length of screw needed.

Combined interdisciplinary treatment of metastatic bone lesions using 3D robot-assisted image-guided navigation : Embolization, biopsy, ablation, and surgery in one operative session

OBJECTIVE

To maximize local tumor control, stabilize affected bones, and preserve or replace joints with minimal interventional burden, thereby enhancing quality of life for empowered living.

INDICATIONS

Suitable for patients with bone metastases, particularly those with severe pain and/or fractures and appropriate life expectancy.

CONTRAINDICATIONS

In primary bone tumors, refer to the sarcoma surgery team for evaluation of wide resection. For patients with poor general condition and/or limited life expectancy (< 6 weeks), consider best supportive care.

SURGICAL TECHNIQUE

Radiological interventions involve angiography and embolization for hypervascularized metastases, followed by precise biopsy and local tumor control through radiofrequency ablation or cryoablation using navigated imaging. The surgical treatment aims to create a durable, minimally invasive construct for stability, considering various options from percutaneous screws with cement augmentation to joint replacement. Intraoperative imaging and 3D scans guide the procedure, ensuring accurate placement of implants and confirming optimal results.

POSTOPERATIVE MANAGEMENT

Postoperative care involves immediate mobilization with pain-adapted full weightbearing and daily physiotherapy. The goal is to regain preoperative mobility. Follow-up with regular clinical and radiographic assessments and CT in the case of tumor progression and complications.

RESULTS

Since introducing the combined surgical and interventional therapy in October 2021, 16 patients have undergone successful procedures. Complications included material failure, component loosening, and surgical site infection. Five patients (31%) died during observation, while surviving patients surpassed their estimated survival, emphasizing the advantages of minimally invasive treatment with durable constructs.

Percutaneous sacral screw fixation alone sufficient for mildly displaced U-type sacral fractures with preserved osseous fixation pathways

PURPOSE

To describe U-type sacral fracture characteristics amenable to percutaneous sacral screw fixation.

METHODS

U-type sacral fractures were identified from a trauma registry at a level 1 trauma center from 2014 to 2020. Patient demographics, injury mechanism, fracture characteristics, and fixation construct were retrospectively retrieved. Associations between fracture pattern and surgical fixation were identified.

RESULTS

82 U-type sacral fractures were reviewed. Six treated with lumbopelvic fixation (LPF) and 76 were treated with percutaneous sacral screws (PSS) alone. Patients receiving LBF had greater sacral fracture displacement in coronal, sagittal, and axial planes compared to patients receiving PSS alone (P < 0.05), negating osseous fixation pathways. All patients went onto sacral union and there were no implant failures or unplanned reoperations for either group.

CONCLUSION

If osseous fixation pathways are present, U-type sacral fractures can be successfully treated with percutaneous sacral screws. LPF may be indicated in more displaced fractures with loss of spinopelvic alignment. Both techniques for U-type sacral fractures result in reliable fixation and healing without reoperations.

Intraoperative computerised tomography scan for percutaneous fixation of the pelvis: a retrospective case series

PURPOSE

Fractures and dislocations of the pelvic ring are complex injuries that when treating require meticulous attention to detail and often specialized technical skill. These injuries can be the result of high-energy trauma, particularly in younger patients, or low energy trauma more often found in the elderly. Regardless of mechanism, these injuries lie on a spectrum of severity and can be treated conservatively or surgically. Percutaneous fixation under fluoroscopic guidance is the preferred standard technique when treating these fractures. This technique can be challenging for a variety of reasons including patient characteristics, intra-operative image quality, fracture morphology, among others.

METHODS

This retrospective study evaluated the use of intra-operative computed tomography (CT) using an O-arm imaging system for critical evaluation of fluoroscopic-guided screw placement in twenty-three patients. We retrospectively reviewed all cases of patients who were treated by three fellowship-trained orthopaedic traumatologists during a one-year span. Patients undergoing percutaneous pelvis fixation using both standard fluoroscopy and intraoperative CT with the Medtronic O-arm® (Minneapolis, MN) imaging system. Additionally, procedures performed included open reduction internal fixation (ORIF) of the pelvic ring, acetabulum, and associated extremity fractures.

RESULTS

Twenty-three patients were included in this study. On average, the use of intraoperative CT added 24.4 min in operative time. Five patients (21.7%) required implant adjustment after O-arm spin. Fourteen patients underwent additional post-operative CT. No secondary revision surgeries were attempted after any post-operative CT.

CONCLUSIONS

Our study suggests that intra-operative CT scan, compared to post-operative CT scan, can be utilized to prevent take-back surgery for misplaced implants and allow for adjustment in real-time.

Insertion sites of iliosacral screws on the posterior ilium: Implications for posterior pelvic fixation

OBJECTIVES

Lateral compression type II pelvic ring injuries can be treated with fixation through open or percutaneous approaches depending on the injury pattern and available osseous fixation pathways. The start site of iliosacral screws to stabilize these injuries should be on the unstable posterior iliac fragment; however, our understanding of start sites for iliosacral screws has not been developed. The purpose of this study is to provide an analysis of iliosacral screw start sites on the posterior ilium to help guide treatment of pelvic ring injuries.

METHODS

One-hundred and seventeen consecutive patients at an academic level I trauma center with pelvic ring injuries who underwent surgical treatment with iliosacral screws were included in the final analysis. The start sites of iliosacral screws with confirmed intraosseous placement on a postoperative computed tomography were mapped on the posterior ilium and analyzed according to the sacral segment and type of iliosacral screw.

RESULTS

One-hundred and seventeen patients were included in the final analysis. Of the total of 272 iliosacral screw insertion sites analyzed, 145 (53%) were sacroiliac-style screws and 127 (47%) were transsacral screws. The insertion sites for sacroiliac-style screws and transsacral screws at different sacral segment levels can vary but have predictable regions on the posterior ilium relative to reliable osseous landmarks.

CONCLUSIONS

Iliosacral screws start sites on the posterior ilium have reliable regions that can be used to plan posterior fixation of pelvic ring injuries.

A Countertraction Closed Reduction Technique in Minimally Invasive Fixation of Recent Type C Pelvic Ring Injuries

OBJECTIVE

Closed reduction of pelvic injuries is a prerequisite and critical step in minimally invasive treatment. Achieving non-invasive closed reduction of pelvic injuries is a challenging clinical problem. This study demonstrated a non-invasive traction technique for closed reduction called countertraction closed reduction technique (CCRT) and evaluated its effectiveness for type C pelvic ring injuries.

METHOD

The data of patients with unstable pelvic fractures treated with CCRT and minimally invasive fixation were retrospectively reviewed from January 2017 to February 2022. Sacroiliac screws were placed to fix the posterior pelvic ring, and internal or external fixation was used to fix the anterior pelvic ring. Operation time, intraoperative blood loss, duration of hospital stay, fracture union and postoperative complications were recorded. Fracture reduction quality was evaluated using the Matta scoring criteria. Functional recovery and general quality of life were evaluated using the Majeed functional scoring criteria.

RESULTS

Thirteen patients (nine males and four females), with an average age of 49.6 years were treated with CCRT and followed up for a mean of 18.5 months. The average operation time was 137.2 minutes (range 92-195 minutes), the average intraoperative blood loss was 31.2 mL (range 10-120 mL) and the average duration of hospital stay was 14.3 days (range 4-32 days). All patients achieved bony union with an average union time of 11.9 weeks (range 10-16 weeks). According to the Matta radiographic criteria, the quality of fracture reduction was excellent in eight patients, good in four, and fair in one. The average Majeed functional score was 89.7 (range 78-100). The functional evaluation revealed that the outcomes were excellent in nine patients, and good in four patients. Complications included incision fat liquefaction in one patient, and heterotopic ossification in another patient. There were no surgical complications as a result of CCRT.

CONCLUSION

CCRT is a non-invasive closed reduction method for minimally invasive fixation of fresh Tile C1 and C2 pelvic fractures. The advantages of CCRT combined with minimally invasive treatment include a small surgical incision, reduced intraoperative bleeding, satisfactory fracture reduction, bone healing and functional recovery.

Navigation versus fluoroscopy in minimalinvasive iliosacral screw placement

INTRODUCTION

When needed operative treatment of sacral fractures is mostly performed with percutaneous iliosacral screw fixation. The advantage of navigation in insertion of pedicle screws already could be shown by former investigations. The aim of this investigation was now to analyze which influence iliosacral screw placement guided by navigation has on duration of surgery, radiation exposure and accuracy of screw placement compared to the technique guided by fluoroscopy.

METHODS

68 Consecutive patients with sacral fractures who have been treated by iliosacral screws were inclouded. Overall, 85 screws have been implanted in these patients. Beside of demographic data the duration of surgery, duration of radiation, dose of radiation and accuracy of screw placement were analyzed.

RESULTS

When iliosacral screw placement was guided by navigation instead of fluoroscopy the dose of radiation per inserted screw (155.0 cGy*cm2 vs. 469.4 cGy*cm2 p < 0.0001) as well as the duration of radiation use (84.8 s vs. 147.5 s p < 0.0001) were significantly lower. The use of navigation lead to a significant reduction of duration of surgery (39.0 min vs. 60.1 min p < 0.01). The placement of the screws showed a significantly higher accuracy when performed by navigation (0 misplaced screws vs 6 misplaced screws-p < 0.0001).

CONCLUSION

Based on these results minimal invasive iliosacral screw placement guided by navigation seems to be a safe procedure, which leads to a reduced exposure to radiation for the patient and the surgeon, a reduced duration of surgery as well as a higher accuracy of screw placement.

Delayed Presentation of Bowel Injury Associated with Pelvic Fragility Fracture in Patient with Bladder Sling: A Case Report

CASE

An 85-year-old woman with a history of bladder mesh sling placement sustained a pelvic fracture and extraperitoneal bladder rupture after a ground-level fall. The patient underwent cystorrhaphy and percutaneous anterior column screw placement. Free air was identified on abdominal computed tomography scan on postoperative day 5. Exploratory laparotomy revealed a sigmoid colon perforation and extensive bowel adhesions to the anterior pelvis.

CONCLUSION

This is the first report describing bowel injury and associated bladder rupture in a pelvic fragility fracture related to a prior bladder mesh sling. This case highlights the importance of obtaining a thorough surgical history when treating pelvic injuries.

The optimal fluoroscopic views to rule out intra-articular screw penetration during acetabular fracture fixation

PURPOSE

To determine the ideal view(s) and the minimum number of intraoperative fluoroscopic views required to rule out any intra-articular screw violation in acetabular fractures fixation.

METHODS

This study was conducted using a series of fluoroscopic examinations of pelvic synthetic models with screws positioned in different planes around the acetabulum. Ten screws were placed in the synthetic pelvis models in different planes of the acetabulum. Seven views were taken for each screw. Radiographic images were evaluated by 14 orthopaedic surgeons who were asked to assess joint violation and the view(s) required for assessment.

RESULTS

The observers' accuracy rate in identifying joint violation was 82.1% for the anterior part of the anterior column and the superior part of the posterior column, 89.3% for the posterior part of the anterior column and the inferior part of the posterior column, and 92.9% for the quadrilateral plate. The sensitivity was 100% for the anterior and posterior parts of the anterior column and the inferior part of the posterior column, 87.5% for the superior part of the posterior column, and 85.7% for the quadrilateral plate. The specificity was 100% for the quadrilateral plate, 80% for the superior part of the posterior column and the posterior part of the anterior column, 78.6% for the inferior part of the posterior column, and 66.7% for the anterior part of the anterior column. There was a strong overall interobserver and intra-observer agreement with intraclass correlation coefficient (ICC) of 0.709 and 0.86, respectively.

CONCLUSIONS

This study confirms the hypothesis that in a concave surface/joint fixation, such as the acetabulum, the probability of joint violation is unlikely if there is no evidence of it within a single fluoroscopic view. In acetabulum fracture fixation with a screw violating the joint, the screw's presence was evident within the joint space in all fluoroscopic views. However, the absence of joint violation in one fluoroscopic view was adequate to rule out joint penetration.

Substitutional semi-rigid osteosynthesis technique for treatment of unstable pubic symphysis injuries: a biomechanical study

BACKGROUND/PURPOSE

The surgical fixation of a symphyseal diastasis in partially or fully unstable pelvic ring injuries is an important element when stabilizing the anterior pelvic ring. Currently, open reduction and internal fixation (ORIF) by means of plating represents the gold standard treatment. Advances in percutaneous fixation techniques have shown improvements in blood loss, surgery time, and scar length. Therefore, this approach should also be adopted for treatment of symphyseal injuries. The technique could be important since failure rates, following ORIF at the symphysis, remain unacceptably high. The aim of this biomechanical study was to assess a semi-rigid fixation technique for treatment of such anterior pelvic ring injuries versus current gold standards of plate osteosynthesis.

METHODS

An anterior pelvic ring injury type III APC according to the Young and Burgess classification was simulated in eighteen composite pelvises, assigned to three groups (n = 6) for fixation with either a single plate, two orthogonally positioned plates, or the semi-rigid technique using an endobutton suture implant. Biomechanical testing was performed in a simulated upright standing position under progressively increasing cyclic loading at 2 Hz until failure or over 150,000 cycles. Relative movements between the bone segments were captured by motion tracking.

RESULTS

Initial quasi-static and dynamic stiffness, as well as dynamic stiffness after 100,000 cycles, was not significantly different among the fixation techniques (p ≥ 0.054).). The outcome measures for total displacement after 20,000, 40,000, 60,000, 80,000, and 100,000 cycles were associated with significantly higher values for the suture technique versus double plating (p = 0.025), without further significant differences among the techniques (p ≥ 0.349). Number of cycles to failure and load at failure were highest for double plating (150,000 ± 0/100.0 ± 0.0 N), followed by single plating (132,282 ± 20,465/91.1 ± 10.2 N), and the suture technique (116,088 ± 12,169/83.0 ± 6.1 N), with significantly lower values in the latter compared to the former (p = 0.002) and no further significant differences among the techniques (p ≥ 0.329).

CONCLUSION

From a biomechanical perspective, the semi-rigid technique for fixation of unstable pubic symphysis injuries demonstrated promising results with moderate to inferior behaviour compared to standard plating techniques regarding stiffness, cycles to failure and load at failure. This knowledge could lay the foundation for realization of further studies with larger sample sizes, focusing on the stabilization of the anterior pelvic ring.

Biomechanics of sacroiliac joint fixation using lag screws: a cadaveric study

BACKGROUND

Iliosacral screw placement is ubiquitous and now part of the surgeon's pelvic trauma armamentarium. More recent evidence supports sacroiliac arthrodesis for treating sacroiliac joint (SIJ) dysfunction in select patients. Regardless of the surgical indication, there are currently no studies examining lag screw compression biomechanics across the SIJ. The objective of this biomechanical investigation was to quantify iliosacral implant compressive loads and to examine the insertion torque and compressive load profile over time.

METHODS

Eight human cadaveric pelvic specimens underwent SIJ fixation at S1 and S2 using 11.5 and 10.0 mm iFuse-TORQ Lag implants, respectively, and standard 7.3 mm trauma lag screws. Load decay analysis was performed, and insertion and removal torques were measured.

RESULTS

For both implants at S1 and S2 levels, the load relaxed 50% in approximately 67 min. Compressive load decay was approximately 70% on average occurring approximately 15 h post-insertion. Average insertion torque for the 11.5 mm TORQ implant at S1 was significantly greater than the trauma lag screw. Similarly, at S2, insertion torque of the 10.0 mm TORQ implant was greater than the trauma lag screw. At S1, removal torque for the 11.5 mm TORQ implant was higher than the trauma lag screw; there was no significant difference in the removal torque at S2.

CONCLUSIONS

In this study, we found that a novel posterior pelvic implant with a larger diameter, roughened surface, and dual pitch threads achieved improved insertion and removal torques compared to a standard screw. Load relaxation characteristics were similar between all implants.

Assessment of sacral osseous fixation pathways for same-level dual transiliac-transsacral screw insertion

INTRODUCTION

The purpose of this study is to (1) describe a pre-operative planning technique using non-reformatted CT images for insertion of multiple transiliac-transsacral (TI-TS) screws at a single sacral level, (2) define the parameters of a sacral osseous fixation pathway (OFP) that will allow for insertion of two TI-TS screws at a single level, and (3) identify the incidence of sacral OFPs large enough for dual-screw insertion in a representative patient population.

METHODS

Retrospective review at a level-1 academic trauma center of a cohort of patients with unstable pelvic injuries treated with two TI-TS screws in the same sacral OFP, and a control cohort of patients without pelvic injuries who had CT scans for other reasons.

RESULTS

Thirty-nine patients had two TI-TS screws at S1. Eleven patients, all with dysmorphic osteology, had two TI-TS screws at S2. The average pathway size in the sagittal plane at the level the screws were placed was 17.2 mm in S1 vs 14.4 mm in S2 (p = 0.02). Twenty-one patients (42%) had screws that were intraosseous and 29 (58%) had part of a screw that was juxtaforaminal. No screws were extraosseous. The average OFP size of intraosseous screws was 18.1 mm vs. 15.5 mm for juxtaforaminal screws (p = 0.02). Fourteen millimeters was used as a guide for the lower limit of the OFP for safe dual-screw fixation. Overall, 30% of S1 or S2 pathways were ≥ 14 mm in the control group, with 58% of control patients having at least one of the S1 or S2 pathways ≥ 14 mm.

CONCLUSIONS

OFPs ≥ 7.5 mm in the axial plane and 14 mm in the sagittal plane on non-reformatted CT images are large enough for dual-screw fixation at a single sacral level. Overall, 30% of S1 and S2 pathways were ≥ 14 mm and 58% of control patients had an available OFP in at least one sacral level.

Consensus for management of sacral fractures: from the diagnosis to the treatment, with a focus on the role of decompression in sacral fractures

BACKGROUND

There is no evidence in the current literature about the best treatment option in sacral fracture with or without neurological impairment.

MATERIALS AND METHODS

The Italian Pelvic Trauma Association (A.I.P.) decided to organize a consensus to define the best treatment for traumatic and insufficiency fractures according to neurological impairment.

RESULTS

Consensus has been reached for the following statements: When complete neurological examination cannot be performed, pelvic X-rays, CT scan, hip and pelvis MRI, lumbosacral MRI, and lower extremities evoked potentials are useful. Lower extremities EMG should not be used in an acute setting; a patient with cauda equina syndrome associated with a sacral fracture represents an absolute indication for sacral reduction and the correct timing for reduction is "as early as possible". An isolated and incomplete radicular neurological deficit of the lower limbs does not represent an indication for laminectomy after reduction in the case of a displaced sacral fracture in a high-energy trauma, while a worsening and progressive radicular neurological deficit represents an indication. In the case of a displaced sacral fracture and neurological deficit with imaging showing no evidence of nerve root compression, a laminectomy after reduction is not indicated. In a patient who was not initially investigated from a neurological point of view, if a clinical investigation conducted after 72 h identifies a neurological deficit in the presence of a displaced sacral fracture with nerve compression on MRI, a laminectomy after reduction may be indicated. In the case of an indication to perform a sacral decompression, a first attempt with closed reduction through external manoeuvres is not mandatory. Transcondylar traction does not represent a valid method for performing a closed decompression. Following a sacral decompression, a sacral fixation (e.g. sacroiliac screw, triangular osteosynthesis, lumbopelvic fixation) should be performed. An isolated and complete radicular neurological deficit of the lower limbs represents an indication for laminectomy after reduction in the case of a displaced sacral fracture in a low-energy trauma associated with imaging suggestive of root compression. An isolated and incomplete radicular neurological deficit of the lower limbs does not represent an absolute indication. A worsening and progressive radicular neurological deficit of the lower limbs represents an indication for laminectomy after reduction in the case of a displaced sacral fracture in a low-energy trauma associated with imaging suggestive of root compression. In the case of a displaced sacral fracture and neurological deficit in a low-energy trauma, sacral decompression followed by surgical fixation is indicated.

CONCLUSIONS

This consensus collects expert opinion about this topic and may guide the surgeon in choosing the best treatment for these patients.

LEVEL OF EVIDENCE

IV.

TRIAL REGISTRATION

not applicable (consensus paper).

A Novel Implant for Superior Pubic Ramus Fracture Fixation-Development and a Biomechanical Feasibility Study

Background and Objectives: Pubic ramus fractures are common in compound pelvic injuries known to have an increased rate of morbidity and mortality along with recurrent and chronic pain, impeding a patient's quality of life. The current standard treatment of these fractures is percutaneous screw fixation due to its reduced risk of blood loss and shorter surgery times. However, this is an intricate surgical technique associated with high failure rates of up to 15%, related to implant failure and loss of reduction. Therefore, the aim of this biomechanical feasibility study was to develop and test a novel intramedullary splinting implant for fixation of superior pubic ramus fractures (SPRF), and to evaluate its biomechanical viability in comparison with established fixation methods using conventional partially or fully threaded cannulated screws. Materials and Methods: A type II superior pubic ramus fracture according to the Nakatani classification was created in 18 composite hemi-pelvises via a vertical osteotomy with an additional osteotomy in the inferior pubic ramus to isolate the testing of three SPRF fixation techniques performed in 6 semi-pelvises each using either (1) a novel ramus intramedullary splint, (2) a partially threaded ramus screw, or (3) a fully threaded ramus screw. Results: No significant differences were detected among the fixation techniques in terms of initial construct stiffness and number of cycles to failure, p ≥ 0.213. Conclusion: The novel ramus intramedullary splint can be used as an alternative option for treatment of pubic ramus fractures and has the potential to decrease the rate of implant failures due to its minimally invasive implantation procedure.

Evaluation of cannulated compression headless screws as an alternative implant for superior pubic ramus fracture fixation: a biomechanical study

BACKGROUND/PURPOSE

Pubic ramus fractures account for the most common types of pelvic fractures. The standard surgical approach for superior pubic ramus fractures (SPRF) is a minimally invasive percutaneous screw fixation. However, percutaneous closed reduction and internal fixation of anterior pelvic ring injuries have high failure rates of up to 15%. The aim of this biomechanical study was to evaluate the stability of SPRF following stabilization with retrograde placed cannulated compression headless screw (CCHS) versus conventional fully and partially threaded screws in an artificial pelvic bone model.

METHODS

SPRF type II as described by Nakatani et al. was created by means of osteotomies in eighteen anatomical composite hemi-pelvises. Specimens were stratified into three groups of six specimens each (n = 6) for fixation with either a 7.3 mm partially threaded cannulated screw (group RST), a 7.3 mm fully threaded cannulated screw (group RSV), or a 7.5 mm partially threaded cannulated CCHS (group CCS). Each hemi-pelvic specimen was tested in an inverted upright standing position under progressively increasing cyclic axial loading. The peak load, starting at 200 N, was monotonically increased at a rate of 0.1 N/cycle until 10 mm actuator displacement.

RESULTS

Total and torsional displacement were associated with higher values for RST versus CCS and RSV, with significant differences between RST and CCS for both these parameters (p ≤ 0.033). The differences between RST and RSV were significant for total displacement (p = 0.020), and a trend toward significance for torsional displacement (p = 0.061) was observed. For both failure criteria 2 mm total displacement and 5° torsional displacement, CCS was associated with significantly higher number of cycles compared to RST (p ≤ 0.040).

CONCLUSION

CCHS fixation presented predominantly superior stability to the standard surgical treatment and could therefore be a possible alternative implant for retrograde SPRF screw fixation, whereas partially threaded screws in group RST were associated with inferior biomechanical stability.

Iliac dysmorphism: defining radiographic characteristics and association with pelvic osseous corridor size

INTRODUCTION

Insertion of iliac wing implants requires understanding of the curvilinear shape of the ilium. This study serves to quantitatively identify the area of iliac inner-outer table convergence (IOTC), characterize the iliac wing osseous corridor, and define the gluteal pillar osseous corridor.

METHODS

Computed tomography scans of 100 male and 100 female hemipelves were evaluated. The iliac wing was studied using manual best-fit analysis of the bounds of the inner and outer cortices. The IOTC was defined as the location of the iliac wing with an intercortical width less than 5 mm. The shortest distance from the apex of the iliac crest to the superior border of the IOTC was defined as the iliac wing osseous corridor. Finally, the width of the gluteal pillar corridor from the gluteus medius tubercle to the ischial tuberosity was measured.

RESULTS

The IOTC is an elliptical area measuring 22.3 cm². All ilia had an area where the inner and outer cortices converged to an intercortical width of less than 5 mm; 48% converged to a single cortex. The shortest mean distance from the superior edge of the iliac crest to the beginning of the IOTC was 20.3 mm in men and 13.8 mm in women (p < 0.001). The gluteal pillar diameter averaged 5.3 mm in men and 4.3 mm in women (p < 0.001).

DISCUSSION

All ilia converge to a thin and frequently unicortical central region. A 4.5 mm iliac wing lag screw will not breach the cortex if it remains within 20 mm or 14 mm distal to the cranial aspect of the iliac crest in males and females, respectively. Not only is the gluteal pillar smaller than previously thought, in 41% of males and 73% of females, it is not be large enough for 5 mm implants.

CONCLUSION

This study quantitatively assesses the dimensions of the IOTC, the iliac crest osseous corridor, and the gluteal pillar. Overall, our findings provide improved understanding of the limits for implant use in the iliac wing as well as better appreciation of the complex osteology of the ilium. This will help surgeons to identify safe areas for implant placement and avoid inadvertent cortical penetration.

An evaluation of the inlet obturator oblique view for sacroiliac and transsacral screw placement

INTRODUCTION

Between 2005 and 2017, the number of closed reduction and internal fixation of pelvic ring injuries increased by 1116%. Percutaneous fixation is currently the only minimally invasive technique that can stabilize the posterior elements of the pelvis. The purpose of this study was to investigate the utility of the inlet obturator oblique view (IOO) with the hypothesis that the IOO view will improve the accuracy of sacroiliac and transsacral screw placement in the S1 or S2 body and improve the accuracy of assessing whether the implant is fully seated against the outer cortex of the ilium.

MATERIALS AND METHODS

Ten male pelvic training models were used. Thirty-six screw configurations were inserted by a fellowship trained orthopedic trauma surgeon in appropriately and inappropriately placed sacroiliac and transsacral screw configurations. These configurations were imaged using fluoroscopy in different planes and saved for survey.

RESULTS

Fourteen orthopedic professionals reviewed 313 fluoroscopic images. Interrater reliability demonstrated marked improvement in assessment of whether the screw head was seated against the outer cortex of the ilium with the IOO view (kappa = 0.841, without IOO kappa = 0.027). There was a statistically significant difference in overall accuracy (p value < 0.001, OR = 1.57, 95% CI = 1.35-1.84) and whether the screw head was seated (p value < 0.001, OR = 8.14, 95% CI = 5.52-11.99) when compared with and without the IOO view (accuracy with IOO view: 85%, accuracy without IOO view: 78.26%; screw seated with IOO view: 93.93%, screw seated without IOO view: 65.54%). There was no significant difference (p value 0.465, OR = 1.13, 95% CI = 0.82-1.55) determining if the screw was in a safe position (safe with IOO view: 84.64%, safe without IOO view: 83.04%).

CONCLUSIONS

Our findings demonstrate that misinterpretation of sacroiliac and transsacral screw placement can occur with the standard fluoroscopic imaging. We suggest the addition of the IOO view increases the overall accuracy of screw placement and whether the screw head is fully seated against the outer table of the ilium. This in turn can improve fixation and potentially improve patient outcomes and decrease adverse events.

Application of the pedicle axis view in percutaneous screw placement for type III fracture dislocation of the sacroiliac joint

AIM

To investigate the clinical application of axial view projection of the pedicle in percutaneous screw placement for type III fracture dislocation of the sacroiliac joint.

METHODS

Percutaneous sacroiliac screw fixation was performed in 29 patients with type III sacroiliac joint fractures under X-ray fluoroscopy (C-arm) using axial view projection of the pedicle after preoperative traction reduction and preoperative preparation. The study included 19 males and 10 females, aged 20 to 75 years old, with a mean age of 42.1 ± 3.4 years.

RESULTS

The total operative time ranged between 44 and 135 min, with a mean of 95.5 ± 9.4 min. The intraoperative fluoroscopy time ranged between 15 and 42 s, with a mean of 25 ± 4.7 s. The intraoperative blood loss ranged between 5 and 10 ml, with a mean of 7.1 ± 1.3 ml. According to the Matta scoring system, excellent outcomes were achieved in 25 cases, whereas good outcomes were achieved in 4 cases. Based on the definition by Neo et al., pedicle screw positions were categorized into four grades: grade 0 (33 screws), grade I (2 screws), grade II (2 screws), and grade III (0 screws). Excellent outcomes were achieved in 94.6% of Grade 0 and I screws. According to Majeed's functional score, 21 cases achieved excellent outcomes, whereas 8 cases achieved good outcomes. The 29 patients were followed between 3 and 18 months, with a mean of 7.1 ± 1.2 months. All patients achieved anatomical reduction with accurate screw placement and successful healing of their fractures, with no cases of bone penetration or neurovascular injury.

CONCLUSION

Axial view imaging of the pedicle using fluoroscopy is a convenient and rapid fluoroscopy method for percutaneous screw placement for type III fracture dislocation of the sacroiliac joint, with a high rate of success, good safety, and short fluoroscopy time.

A cadaveric biomechanical evaluation of anterior posterior compression II injuries

PURPOSE

Pelvic fractures are associated with high morbidity and often require surgical intervention. An Anterior Posterior Compression (APC) II injury consists of disruption at the pubic symphysis and anterior sacroiliac joint. Studies investigating specific ligamentous contributions would aid in development of novel fixation techniques. The objective of this study is to determine the level of pelvic destabilization from progressive soft tissue disruptions associated with APC II injuries.

METHODS

Six fresh-frozen cadaveric pelvises were dissected of soft tissues, preserving joint capsules and ligaments. Each pelvis was secured in a double-leg stance and joint motion was tracked with the specimens cyclically loaded to 60% body weight. Each specimen was measured in the intact state and again following stepwise destabilization to an APC II injury model (PS: sectioned pubic symphysis, IPS JOINT: PS + ipsilateral anterior sacroiliac, sacrotuberous, sacrospinous ligaments sectioned, IPS LIGS: IPS JOINT + ipsilateral interosseous ligaments sectioned, IPS JOINT+CONT ASI: IPS LIGS + contralateral anterior sacroiliac ligament disruption).

RESULTS

Compared to the intact state, there was a statistically significant increase in movement in the IPS JOINT (ipsilateral 177%, p<0.001; contralateral 46%, p<0.005) and IPS JOINT+CONT ASI (ipsilateral 184%, p<0.002; and contralateral 62%, p<0.002) states bilaterally. No significant change was demonstrated in the PS or IPS LIGS state.

CONCLUSION

Disruption of ipsilateral ligamentous structures destabilized both sacroiliac joints. The interosseous and posterior sacroiliac ligaments provide the majority of stability of the sacroiliac joint and will likely benefit most from surgical stabilization.

LEVEL OF EVIDENCE

mechanism-based reasoning.

Use of calcaneal plates in the treatment of posterior pelvic ring injuries and displaced iliac blade fractures- A case series

Introduction

The operative fixation of pelvic ring injuries and associated acetabulum fractures presents a challenging scenario to most of the orthopaedic trauma surgeons. Current development of anatomically contoured reconstruction (ACR) plates gained popularity in fixing complex pelvic ring fractures. This study was done to assess the functional and radiological outcomes using of lateral wall stainless steel (LWSS) calcaneal plates in posterior pelvic ring injuries and displaced iliac blade fractures.

Materials and methods

Retrospectively selected eight cases of pelvic ring injuries planned for fixing posterior pelvic instability and iliac blade fractures using LWSS plates. Mean follow-up was 18 months (Range 12-26 months).

Results

Average time for radiological bony union achieved in 18 weeks (Range 13-22). Seven patients returned to their normal work. Average Majeed score was 60 (Range 50-68). Mean duration of surgery was 160 min (Range 120-200).

Conclusion

This technique can be routinely used as supplementary fixation for posterior pelvic ring instability and iliac blade fractures. LWSS calcaneal plates showed no screw breakage or implant failure. Further this technique was cost effective in developing countries with limited resources.

Robot-assisted versus conventional percutaneous sacroiliac screw fixation for posterior pelvic ring injuries: a systematic review and meta-analysis

PURPOSE

Robot-assisted pelvic screw fixation is a new technology with promising benefits on intraoperative outcomes for patients with posterior pelvic ring injuries. We aim to compare robot-assisted pelvic screw fixation to the traditional fluoroscopy-assisted technique with regards to intraoperative and postoperative outcomes.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used along with a search of electronic information to identify all studies comparing the outcomes of robot-assisted versus conventional screw fixation in patients with posterior pelvic ring injuries. Primary outcomes included operative duration (minutes), intraoperative bleeding (mL), fluoroscopy exposure and intraoperative drilling frequency. Secondary outcome measures included Majeed score, healing time (minutes) and rate (%), postoperative complications, screw positioning, incision length (cm) and guide wire insertion times (minutes). The random effects model was used for analysis.

RESULTS

Four observational studies including a total of 294 patients were identified. There was a significant difference between robot-assisted and conventional groups in terms of operative duration (MD = - 24.66, p < 0.05), intraoperative bleeding (MD = - 10.37, P < 0.05), fluoroscopy exposure (MD = - 2.15, P < 0.05) and intraoperative drilling frequency (MD = - 2.42, P =  < 0.05). For secondary outcomes, no significant difference was seen in Majeed score, healing time and rate and postoperative complications. The robot-assisted group had better screw positioning, smaller incision length, and shorter anaesthesia and guide wire insertion times.

CONCLUSIONS

Robot-assisted fixation has superior intraoperative outcomes compared to conventional fixation. Further studies are needed to look at postoperative outcomes as there is no significant difference in postoperative prognosis between the techniques.

TiRobot‑assisted versus conventional fluoroscopy-assisted percutaneous sacroiliac screw fixation for pelvic ring injuries: a meta‑analysis

BACKGROUND

The TiRobot is the only robot that has been reported in the literature for posterior pelvic injuries. We aim to compare TiRobot-assisted pelvic screw fixation with the conventional fluoroscopy-assisted percutaneous sacroiliac screw fixation.

METHODS

We conducted a meta-analysis to identify studies involving TiRobot‑assisted versus conventional percutaneous sacroiliac screw fixation for pelvic ring injuries in electronic databases, including Web of Science, Embase, PubMed, Cochrane Controlled Trials Register, Cochrane Library, Highwire, CBM, CNKI, VIP, and WanFang database, up to April 2022. The following keywords were used: "TiRobot," "robot," "robotic," "pelvic fracture," "screw fixation," "percutaneous," and "pelvic ring injury." Pooled effects of this meta-analysis were calculated using STATA SE version 15.0.

RESULTS

Compared with conventional fluoroscopy-assisted percutaneous sacroiliac screw fixation, TiRobot will result in less radiation exposure time of screw implantation (P = 0.000), less frequency of intraoperative fluoroscopy (P = 0.000), fewer guide wire attempts (P = 0.000), less intraoperative blood loss (P = 0.005), better screw accuracy (P = 0.011), better Majeed score (P = 0.031), and higher overall excellent and good rates of Majeed score (P = 0.018). However, there were no significant differences in terms of operative time (P = 0.055), fracture healing time (P = 0.365), and overall excellent and good rate of reduction accuracy (P = 0.426) between the two groups.

CONCLUSION

TiRobot-assisted fixation has less intraoperative fluoroscopy and intraoperative blood loss, superior screw accuracy, and Majeed score compared with conventional percutaneous sacroiliac screw fixation. TiRobot has no significant effect on operative time, fracture healing time, and reduction accuracy. Given the relevant possible biases in our meta-analysis, we required more adequately powered and better-designed RCT studies with long-term follow-up to reach a firmer conclusion.

Identifying safe corridors for anterior pelvic percutaneous instrumentation using computed tomography-based anatomical relationships

INTRODUCTION

Percutaneous anterior pelvic ring instrumentation is performed for retrograde screw fixation of ramus fractures, as well as for repair of pubic symphysis diastasis. The anatomic relationships of critical structures around the anterior pelvic ring, such as the spermatic cord and round ligament, have been described in only a few studies regarding the risk of iatrogenic injury during surgery. Our goal is to further describe these relationships, as well as provide radiographic information on safe corridors for percutaneous fixation.

METHODS

Eighty (80) axial computed tomography scans of the abdomen, obtained for non traumatic diagnostic purposes and screened for prior abdominal trauma or procedures, were evaluated by 3 fellowship trained radiologists. Mid-symphyseal cuts were used to obtain several measurements relative to the spermatic cords (SC) or round ligaments (RL): inter-cord or inter-ligament distance, skin to cortex of symphysis distance (vertical), skin to cortex of symphysis distance (oblique), safe corridor distance (between SC/RL and femoral triangle), center safe angle (relative to bilateral ischia), maximal safe angle, and minimal safe angle.

RESULTS

There were 41 male and 39 female scans included in the final analysis. The average inter-cord distance was 50.2 mm, skin to cortex vertical distance of 43.0 mm, skin to cortex oblique distance of 83.5 mm, safe corridor distance 26.3 mm, center safe angle 19.3˚, maximal safe angle 32.3˚, and minimal safe angle 13.6˚. These were further broken down by range and gender in Table 1. Agreement between radiologists was high for these different measurements with the exception of the skin to cortex oblique distance in female patients and the maximal safe angle in female patients, due to absence of round ligament in a majority of the scans. The round ligament was only present at the mid-symphyseal level for our three reviewers in 37/39, 36/39, and 24/39 of female patient scans.

CONCLUSIONS

We have identified defined safe corridors for instrumentation of the anterior pelvic ring that can assist the surgeon in percutaneous application of fixation for fracture care.

Distal sacral nerve roots severed by a fragility fracture of the sacrum: a case report

Background

Owing to the aging population, fragility fractures of the pelvis are occurring more frequently. Fixation of the fracture and stabilization of the pelvic ring usually provide good clinical results. A case of distal sacral nerve roots severed by a fragility fracture of the sacrum is presented.

Case presentation

A 62-year-old Japanese woman with schizophrenia with low back pain, gait disorder, dysuria, and fecal incontinence presented to an emergency department, and plain X-rays showed no findings. She also complained of dysuria, and neurogenic bladder and cystitis were diagnosed. One month later, she was admitted to a psychiatric hospital for exacerbation of schizophrenia. In hospital, she had a urethral catheter inserted and spent 3 months in bed. She was referred to our orthopedic department because a gait disorder was discovered after her mental condition improved and she was permitted to walk. On examination, she could not walk and had decreased sensation from the buttocks to both posterior thighs and around the anus and perineum. Manual muscle testing of her lower limbs showed mild weakness of about 4 in bilateral flexor hallucis longus and gastrocnemius, and bilateral Achilles tendon reflexes were lost. Her anal sphincter did not contract, and urinary retention continued after urethral catheter removal. Imaging examinations showed an H-shaped sacral fracture consisting of a transverse fracture with displacement of the third sacral vertebra and vertical fractures of the bilateral sacral wings, with severe stenosis of the spinal canal at the site of the transverse fracture. The patient was diagnosed as having bladder and rectal dysfunction due to a displaced, unstable sacral fracture. First to third sacral laminectomy and alar–iliac fixation using percutaneous pedicle screws and sacral alar–iliac screws were then performed. The bilateral distal sacral nerve roots (S3, S4, S5) were completely severed at the second to third sacral levels, but bilateral second sacral nerve roots were not compressed from the bifurcation to the sacral foramen. Postoperatively, bladder and rectal dysfunction remained, but the low back pain was alleviated. Two weeks postoperatively, she could walk with a walker and was discharged. Three months after the operation, bone fusion of the fracture was observed.

Conclusions

In cases of bladder–rectal dysfunction with low back pain, the possibility of sacral fracture should be considered, and computed tomography, magnetic resonance imaging, and X-ray examinations should be performed. Even sacral fractures without displacement require attention because they can cause serious injury in the event of a nerve root being severed if not diagnosed early and given appropriate treatment.

Supraacetabular osseous corridor: defining dimensions, sex differences, and alternatives

INTRODUCTION

The supraacetabular (SA) corridor extends from the anterior inferior iliac spine to the posterior ilium and can safely accommodate implants to stabilize pelvic and acetabular fractures. However, quantitative analysis of its dimensions and characteristics have not been thoroughly described. This study seeks to define the dimensions, common constriction points, and any alternative trajectories that would maximize the corridor diameter.

METHODS

Computed tomography of 100 male and 100 female hemipelves without osseous trauma were evaluated. The corridor boundaries were determined through manual best-fit analysis. The largest intercortical cylinder within the pathway was created and measured. Alternative trajectories were tested within the SA boundaries to identify another orientation that maximized the diameter of the intercortical cylinder.

RESULTS

The traditional SA corridor had a mean diameter of 8.3 mm in men and 6.2 mm in women. This difference in diameter is due to a more S-shaped ilium in women. A larger alternative SA corridor was found that had a less limited path through the ilium and measured 11.3 mm in men and 9.9 mm in women. These dimensions are significantly different compared to those of the traditional SA corridor in both men and women.

CONCLUSIONS

In men, the SA corridor allows for the safe passage of most hardware used in pelvic and acetabular fractures. However, in women, the SA corridor is restricted by a more S-shaped ilium. An alternative trajectory was found that has a significantly larger mean diameter in both sexes. Ultimately, the trajectory of hardware will be dictated by the clinical scenario. When large implants are needed, especially in women, we recommend considering the alternative SA corridor.

Percutaneous posterior transiliac plate versus iliosacral screw fixation for posterior fixation of Tile C-type pelvic fractures: a retrospective comparative study

BACKGROUND

This study aimed to compare the clinical outcomes and complications between two minimally invasive surgical techniques: percutaneous transiliac plate fixation and iliosacral (IS) screw fixation for the treatment of Tile C-type pelvic bone fractures.

METHODS

We retrospectively reviewed the data of 77 consecutive patients with Tile C pelvic ring injuries who underwent either percutaneous transiliac plate fixation or IS screw fixation in a single academic center between November 2007 and January 2018. We recorded patients' demographics, surgery-related data, and postoperative surgical outcomes and compared the incidence of complications and revision surgery rates between the two groups.

RESULTS

Overall, 14 patients were included in the plate group, while 63 were included in the IS screw fixation group. No significant differences were observed in the patients' demographics between the two groups except for a longer interval from injury to surgery (13.5 days vs. 5.4 days, P = 0.001). Both groups acquired fracture union in all cases. There was one case of infection requiring surgical debridement in the plating group. Notably, nerve injury (n = 3) and implant loosening (n = 5) occurred in the IS screw group, but the difference was not significant.

CONCLUSIONS

Both percutaneous posterior transiliac plating and IS screw fixation in patients with Tile C-type pelvic bone fractures showed good results. We recommend IS screw fixation as the primary treatment and propose posterior plating as treatment for sacral dysmorphism and bilateral sacral alar fractures in patients with spinopelvic dissociation.

LEVEL OF EVIDENCE

III.

What happens at the L5/S1 facet joint when implants are placed across the sacroiliac joint?

BACKGROUND

Injuries to the posterior pelvic ring are often stabilized with fixation across the sacroiliac joint (SIJ). However, the compensatory changes at the neighboring L5/S1 facet joint are unknown. The objective of this study was to determine the compensatory change in pelvic kinematics and contact forces at the L5/S1 facet joint after fixation across the sacroiliac joint (SIJ) using a cadaveric model.

METHODS

Five fresh-frozen cadaveric pelvis specimens were dissected to remove non-structural soft tissue. Retroreflective markers were fixed to the L5 body, S1 body and bilateral anterior superior iliac spines to represent the motion of L5, S1 and the ileum, respectively. Pressure sensors were inserted in both L5/S1 facet joints. Testing was performed using a robotic system that applied load to mimic ambulation. Testing was performed prior to SIJ fixation, after unilateral SIJ fixation and bilateral fixation.

RESULTS

Contact force at the L5/S1 facet joint significantly increased by 55% from 48.4 N to 75.2 N following unilateral fixation (p = 0.0161) and increased by 100% to 96.9 N after bilateral fixation (p = 0.0038). Unilateral SIJ fixation increased flexion of the ilium relative to L5 from 1.2° to 2.0° (p = 0.01) and increased axial rotation of L5 relative to S1 from 0.7° to 1.6° (p = 0.001). Bilateral fixation increased flexion of the ilium relative to L5 to 2.0° from 1.2° prior to fixation (p = 0.001), increased axial rotation of L5 relative to S1 to 1.2° from 0.7° prior to fixation (p = 0.002) and increased flexion of L5 relative to S1 to 2.4° from 1.5° prior to fixation (p = 0.04).

CONCLUSION

The L5/S1 facet joint experiences compensatory increased motion under increased contact force after unilateral and bilateral SIJ fixation, possibly predisposing it to adjacent segment arthritis.

LEVEL OF EVIDENCE

V, cadaveric study.

The Utility of the Hyperinlet View in Posterior Fixation of Pelvic Ring Injuries

Percutaneous pelvic fixation has evolved into a widely used, safe, and effective treatment option in the management of pelvic ring injuries. Proper preoperative and intraoperative radiographic evaluation of these injuries is critical to ensure safe placement of fixation of the pelvis. Traditional intraoperative views for posterior pelvic ring fixation include the pelvic inlet and outlet views. We propose that the intraoperative use of a hyperinlet view, which uses additional cranial tilt relative to the traditional inlet view, is helpful to better delineate the spinal canal and thereby better define the posterior limit of the osseous fixation pathway of the upper sacral segments. This study illustrates the use of this novel radiographic view and presents a patient cohort in which it was effectively used.

Is unrestricted weight bearing immediately after fixation of rotationally unstable pelvic fractures safe?

INTRODUCTION

Rotationally unstable pelvic fractures treated with surgical fixation have traditionally been treated with restricted weight bearing on the affected side for 6-8 weeks post operatively. We have been developing pelvic fixation standards to allow for unrestricted weight bearing immediately post operatively in type B rotationally unstable pelvic fractures.

AIMS

To assess for safety and efficacy of allowing unrestrictive weight bearing in this cohort of patients, we have clinically and radiologically monitored outcomes up to two years post operatively.

METHODS

Through retrospective review, two cohorts of patients with Tile Type B pelvic fractures were identified that were treated at the Royal Adelaide Hospital, South Australia. Patient demographics, injury classification, surgical fixation and weight bearing status post operatively was recorded. One cohort of patients was allowed to fully weight bear post operatively, whilst the other was treated with 6 weeks of restricted post op weight bearing. At clinical follow up, post-operative x-rays were assessed for loss of reduction, screw or plate breakage and reoperation.

RESULTS

Between January 2018 and January 2021, 53 patients with rotationally unstable pelvic fractures that underwent surgical fixation were included in this study. One group of patents were allowed to immediately weight bear as tolerated (WBAT) post operatively (n = 28) and the other with restricted weightbearing (RWB) (n = 25). There was 1 re operation for failure of fixation in each group. Metalwork breakage was more common in the WBAT group than in the RWB group and this was seen only in APC fractures. This increase in metalwork failure was not associated with loss of reduction.

CONCLUSIONS

With surgical fixation, Tile type B rotationally unstable pelvic fractures can be allowed immediate weight bearing post operatively. We found this to be safe and effective, employing surgical strategies to address both anterior and posterior injuries to allow immediate unrestricted weight bearing. Broken metalwork was more commonly seen in the WBAT group but this was not associated with loss of reduction or reoperation.

Posterior hinge fixation for the treatment of unstable traumatic sacroiliac joint injuries

INTRODUCTION

Posterior hinge fixation (PHF) is a sacroiliac joint fixation method indicated for the surgical treatment of unstable pelvic ring fractures (tile C).

HYPOTHESIS

PHF yields good functional outcomes based on the Majeed score at more than 1 year of follow-up.

METHODS

A single-center, retrospective study of patients who had a Tile C pelvic ring fracture, who were operated by PHF and who were evaluated at a minimum follow-up of 1 year. The functional outcome was determined using the Majeed score and pain was evaluated by the patients using a visual analog scale (VAS). The preoperative, intraoperative and postoperative data, complications and sequelae were documented. A CT-scan was done at least 1 year after the surgical treatment to determine the SI joint's reduction and fusion.

RESULTS

Included were 22 patients (59% men) who had a mean age of 37.3±11.9 years; 21 of these patients were reviewed at a mean of 4.8±4 years. The mean Majeed score at the final assessment was 76.4 points±15.3, with 24% of patients having excellent results (n=5), 53% having good results (n=11), 19% having average results (n=4) and 5% having poor results (n=1). The mean pain level on VAS was 28±23mm. Of the eight surgical site infections, seven occurred in the PHF (88%). CT-scans taken at 1 year postoperative were compared to the preoperative scans. The pelvic opening was reduced by -9±6 (p<0.01), SI diastasis by -11mm±9 (p<0.001), vertical displacement by-7mm±8 (p<0.001), symphysis opening by -15mm±15 (p<0.001), median transverse diameter by -10mm±9 (p<0.001) and bispinal diameter by -5mm±7 (p<0.001). SI fusion was confirmed in 43% of patients (n=9).

CONCLUSION

PHF is a surgical instrumentation method that provides satisfactory long-term reduction of Tile C pelvic ring fractures. The clinical outcomes are good or excellent in 77% of cases. The perioperative morbidity is marked by surgical site infections, all of which healed.

LEVEL OF EVIDENCE

IV; retrospective, non-comparative cohort study.

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.

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.

Is the Iliac Cortical Density Similarly Positioned in the Developing Pediatric Pelvis?

OBJECTIVES

The iliac cortical density (ICD) is a critical fluoroscopic landmark for pelvic percutaneous screw placement. Our purpose was to evaluate the ICD as a landmark in pediatrics and quantify the diameter of osseous pathways for 3 screw trajectories: iliosacral (IS) at S1 and transiliac-transsacral (TSTI) at S1 and S2.

METHODS

Two hundred sixty-seven consecutive pelvic CT scans in children 0-16 years of age were analyzed. ICD and S1 vertebral heights were measured at multiple regions along S1. Their height and corresponding ratios, as well as osseous screw corridor dimensions were compared between age groups and by the dysmorphic status.

RESULTS

In the nondysmorphic pelvises, S1 height, ICD height, and the ICD to S1 height ratio increased across age groups for all locations (P < 0.001). All 3 screw pathway diameters increased with age (P < 0.001). In the dysmorphic group, there was no increase in ICD to S1 height ratio with age. Except for the age 0-2 group, the ICD to S1 height ratios were significantly larger in the nondysmorphic group. In the dysmorphic group, S1 TSTI pathway remained narrow with age, whereas IS at S1 and TSTI at S2 had a significant increased diameter with age (P < 0.001).

CONCLUSION

The ICD is a useful fluoroscopic landmark for percutaneous screw placement in the pediatric pelvis. For nondysmorphic pelvises, the ICD to S1 height ratio, as well as osseous corridors for IS, TSTI at S1, and TSTI at S2 screw trajectories increase significantly with age. The margin for safe screw placement in S1 is smaller for younger and dysmorphic pelvises.

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.

Techniques for predicting and avoiding unintentional biplanar movements during iliosacral screw placement

The technique for placing iliosacral screws typically involves the surgeon using an inlet and outlet view as the primary means for assessing the anteroposterior and craniocaudal position of the guidewire, respectively. However, because these views are rarely, if ever, orthogonal to one another, this technique will inevitably lead to unintentional biplanar movements. These unintentional movements, in turn, require correction, which can increase operating room and fluoroscopic time. Here we calculate the degree and magnitude of these unintentional movements. Additionally, we provide a simple technique for minimizing or eliminating them altogether.

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.

Systematic review of sacroiliac joint motion and the effect of screw fixation

BACKGROUND

Pelvic injuries that disrupt the sacroiliac joints often require surgical intervention to restore stability. Quantitative characterization of sacroiliac motion in response to physiologic loading provides important metrics of adequate fixation in the evaluation of newly emerged fixation techniques. The objective of this study was to systematically review and evaluate biomechanical evidence on the motion of the sacroiliac joint in its normal, destabilized, and stabilized states.

METHODS

We searched the PubMed database for studies available until June 2020 using keywords: sacroiliac, biomechanic*, and fixation. Publications of any in vivo or in vitro biomechanical study that included measurements of the range of motion at the sacroiliac joint were considered.

FINDINGS

We identified and screened 176 total records, and 13 articles of them met inclusion criteria and were used in this review. The average sacroiliac joint range of motion of the intact pelvis was 1.88° in flexion/extension, 0.85° in lateral bending, 1.26° in axial rotation. Of the 13 studies, four reported sacroiliac motion from a destabilized state, while seven reported the motion after stabilization. A forest plot of the stabilized data set in flexion/extension showed that while the heterogeneity was poor, the weighted effect size of the changes from the intact state to the stabilized state was 0.0%.

INTERPRETATION

Quantitative evidence on sacroiliac joint motion relating to pelvic injuries or fixation is limited. Our results indicate that the pooled intact range of motion from the literature may serve as a viable reference to quantify the effectiveness of new stabilization techniques.

LEVEL OF EVIDENCE

Level V, systematic review.

STUDY TYPE

Therapeutic- investigating the results of a treatment.

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.

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.

Low Superior Pubic Ramus Screw Failure Rate With Combined Anterior and Posterior Pelvic Ring Fixation

OBJECTIVES

To determine whether fracture pattern, implant size, fixation direction, or the amount of posterior pelvic ring fixation influences superior ramus medullary screw fixation failure.

DESIGN

Retrospective cohort review.

SETTING

Regional Level 1 trauma center.

PATIENTS/PARTICIPANTS

After exclusion criteria, 95 patients with 111 superior ramus fractures with 3 months minimum follow-up were included.

INTERVENTION

All patients underwent anterior and posterior pelvic ring fixation.

MAIN OUTCOME MEASUREMENTS

Comparison of immediate postoperative radiographs and/or computer tomography scan with the latest postoperative image to calculate interval fracture displacement and implant position. Postoperative fracture displacement or implant position change greater than 1 cm were considered fixation failures.

RESULTS

Five screws were defined as failures (4.5%), including 3 retrograde, 3 with bicortical fixation, 4 with a 4.5-mm screw, and 1 with a 7.0-mm screw. Fracture patterns included 2 oblique and 3 comminuted fractures. Based on the Nakatani classification, there were 3 zone II, 1 zone I, and 1 zone III. Failure modes included 3 with cut-out along the screw head and 1 cut-out and 1 cut-through at the screw tip.

CONCLUSIONS

Our incidence of superior pubic ramus intramedullary screw fixation failure was 4.5%. Even with anterior and posterior fixation along with precise technique, failures still occur without a common failure predictor. The percutaneous advantages and proven strength provided by an intramedullary implant make it desirable to help reestablish global pelvic ring stability. Biomechanical and clinical studies are needed to further understand intramedullary superior ramus screw fixation.

LEVEL OF EVIDENCE

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

Transverse and transverse-variant acetabular fractures with ipsilateral sacroiliac joint injuries: A technical note for reduction and stabilization

Transverse and T-type acetabular fractures are high energy fractures that may be associated with a disruption of the pelvic ring. While several studies report upon clinical findings and outcomes associated with combination injuries of the pelvic ring and acetabulum, there are limited reports discussing surgical treatment strategies for reduction and stabilization. Herein we focus on describing reduction and stabilization techniques of transverse or transverse-variant acetabular fractures with an associated ipsilateral partial disruption of the sacroiliac joint.

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.

Navigated percutaneous screw fixation of the pelvis with O-arm 2: two years' experience

Aim To evaluate the case series of the patients operated with percutaneous fixation by the navigation system based on 3D fluoroscopic images, to assess the precision of a surgical implant and functional outcome of patients. Methods A retrospective study of pelvic ring fractures in a 2-year period included those treated with the use of the O-Arm 2 in combination with the Stealth Station 8. Pelvic fractures were classified according to the Tile and the Young-Burgess classification. All patients were examined before surgery, with X-rays and CT scans, and three days after surgery with additional CT scan. The positioning of the screws was evaluated according to the Smith score, the outcome with the SF-36. Results Among 24 patients 18 were with B and six with C type fracture according to Tile, while eight were with APC, 10 LC, and six with VS type according to Young-Burgess classification. All patients were treated in the supine position, except two. A total of 41 iliosacral or transsacral screws and five anterior pelvic ring screws were implanted. The medium surgical time per screw was 41 minutes. There was a perfect correspondence of screw scores value from post-operative CT and intraoperative fluoroscopy. The mean screw score value was 0.92. There were no cases of poor positioning. The median follow-up was 17.5 months. The patients were satisfied with their health condition on SF-36. Conclusion The use of the O-arm guarantees great precision in the positioning of the screws and reduced surgical times with excellent clinical results in patients.

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.

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.

Plate versus sacroiliac screw fixation for treating posterior pelvic ring fracture: a Systematic review and meta-analysis

BACKGROUND

Whether plate fixation or sacroiliac (SI) screw fixation is the better treatment for posterior pelvic ring disruption is controversial. The aim of this systematic review and meta-analysis was to compare the two fixation methods.

MATERIAL AND METHODS

The MEDLINE, Embase, and Cochrane Library databases were systematically searched for studies comparing plate and SI screw fixations in posterior pelvic ring injuries. Intraoperative variables, postoperative complications, and clinical/radiological scores were compared between the techniques.

RESULTS

Eleven studies were included in the qualitative synthesis, and nine in the meta-analysis. The meta-analysis included 202 patients who underwent plate fixation and 258 patients who underwent SI screw fixation. The incision length and mean blood loss were greater in the plate group than in the SI screw group (standard mean difference (SMD) = 7.29, 95% confidence interval (CI): 3.18-11.40; SMD = 5.09, 95% CI: 2.08-8.09, respectively). Patients in the SI screw group had more X-ray exposure than those in the plate group (SMD = -5.96, 95% CI: -7.95-3.97). There were no differences in operation time and intraoperative complications (SMD = -1.42, 95% CI: -3.90-1.05; OR = 0.92, 95% CI: 0.05-18.60, respectively). The duration of hospital stay was longer in the plate group (SMD = 2.21, 95% CI: 1.74-2.68). There were no differences in postoperative neurological complications, infection rate, and nonunion rate (OR = 1.62, 95% CI: 0.20-13.21; OR = 2.10, 95% CI: 0.74-5.94; OR = 1.12, 95% CI: 0.26-4.87, respectively), but implant loosening was more common in the SI screw group (OR = 0.18, 95% CI: 0.04-0.87). There was no difference in revision surgery (OR = 0.23, 95% CI: 0.02-2.14). The total excellent rating according to the postoperative Majeed functional and Matta scores was higher in the SI screw group (OR = 0.43, 95% CI: 0.20-0.91; OR = 0.24, 95% CI: 0.08-0.74, respectively).

CONCLUSIONS

SI screw fixation was superior to plate fixation in the functional and radiological scores, but implant loosening was more common for the treatment posterior pelvic ring injuries.

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.

Algo-Functional Indexes and Spatiotemporal Parameters of Gait after Sacroiliac Joint Arthrodesis

Aims of the study were to evaluate the reliability and validity of the Italian version of the Majeed and Iowa questionnaires and to investigate the long-term surgical outcomes following sacroiliac joint arthrodesis. Twenty one patients who underwent a sacroiliac joint arthrodesis and 21 healthy subjects were evaluated. The experimental procedure consisted of gait analysis and a physical activity assessment (in both groups) and of administration of outcome questionnaires and pain assessment (in the patient group). The Majeed and Iowa questionnaires showed excellent reliability, excellent (for the Majeed questionnaire) and good (for the Iowa questionnaire) construct validity, and poor convergent validity (for both questionnaires) relative to walking speed. Most of the patients reported no pain and minimum pain-related disability and their physical activity profile was comparable to healthy controls. Patients showed an impaired walking performance (i.e., they walked slower and using shorter steps) compared with healthy controls. Long-term walking pattern abnormalities following sacroiliac joint arthrodesis may occur despite excellent clinical results. Given their excellent reliability and construct validity, the Majeed and Iowa questionnaires can be used in combination with the assessment of spatiotemporal gait parameters for the prognostic assessment and/or follow-up of surgical patients.

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.

3D - Navigated percutaneous screw fixation of pelvic ring injuries - a pilot study

INTRODUCTION

Screw fixation of pelvic ring fractures is a common, but demanding procedure and navigation techniques were introduced to increase the precision of screw placement. The purpose of this case series is to demonstrate a lower screw malposition rate using percutaneous fixation of pelvic ring fractures and sacroiliac dislocations guided by navigation system based on 3D-fluoroscopic images compared to traditional imaging techniques and to evaluate the functional outcomes of this innovative procedure.

PATIENT AND METHODS

10 cases of disrupted pelvic ring lesions treated in our hospital from February 2018 to December 2018 were included for closed reduction and percutaneous screw fixation of using with O-Arm and the acquisition by the Navigator. Preoperative assessment was performed on the patients by means of X Ray imaging and CT scan. Routine CT was carried out on third postoperative day to evaluate screw placement. Measures of radiation exposure were extracted directly from reports provided by system. Quality of life was evaluated by SF 36-questionnaire 6 months after surgery.

RESULTS

12 iliosacral- and 2 ramus pubic-screws were inserted. In post-operative CT-scans the screw position was assessed and graded using the score described by Smith. No wound infection or iatrogenic neurovascular damage were observed. No re-operations were performed. The exposure to radiation is, for the patient, slightly greater than that resulting from the use of traditional fluoroscopic systems, while it is naught for the surgical team, which at the time of image acquisition is located outside the room.

DISCUSSION AND CONCLUSION

The execution of an intraoperative 3D-fluoroscopic scan can on its own suffice as a post-operative control examination since its accuracy is similar to that of the post-operative CT. The use of a navigated 3d fluoroscopy exposes the patient to an amount of radiation slightly greater than that of traditional fluoroscopy, but the dose is lower than a CT examination. For the operating team, exposure to radiation is naught. 3D-fluoroscopic navigation is a safe tool providing high accuracy of percutaneous screw placement for pelvic ring fractures. Finally, despite the small cohort of patients studied, the excellent results obtained regarding the patients' quality of life and the absence of complications allow us to look positively at the future of this technique, which needs further studies and improvement.