Diastasis of the pubic symphysis peculiar to horse riders: modern aspects of pelvic pommel injuries

Multi-body 3D-2D registration for image-guided reduction of pelvic dislocation in orthopaedic trauma surgery

Surgical reduction of pelvic dislocation is a challenging procedure with poor long-term prognosis if reduction does not accurately restore natural morphology. The procedure often requires long fluoroscopic exposure times and trial-and-error to achieve accurate reduction. We report a method to automatically compute the target pose of dislocated bones in preoperative CT and provide 3D guidance of reduction using routine 2D fluoroscopy. A pelvic statistical shape model (SSM) and a statistical pose model (SPM) were formed from an atlas of 40 pelvic CT images. Multi-body bone segmentation was achieved by mapping the SSM to a preoperative CT via an active shape model. The target reduction pose for the dislocated bone is estimated by fitting the poses of undislocated bones to the SPM. Intraoperatively, multiple bones are registered to fluoroscopy images via 3D-2D registration to obtain 3D pose estimates from 2D images. The method was examined in three studies: (1) a simulation study of 40 CT images simulating a range of dislocation patterns; (2) a pelvic phantom study with controlled dislocation of the left innominate bone; (3) a clinical case study investigating feasibility in images acquired during pelvic reduction surgery. Experiments investigated the accuracy of registration as a function of initialization error (capture range), image quality (radiation dose and image noise), and field of view (FOV) size. The simulation study achieved target pose estimation with translational error of median 2.3 mm (1.4 mm interquartile range, IQR) and rotational error of 2.1° (1.3° IQR). 3D-2D registration yielded 0.3 mm (0.2 mm IQR) in-plane and 0.3 mm (0.2 mm IQR) out-of-plane translational error, with in-plane capture range of ±50 mm and out-of-plane capture range of ±120 mm. The phantom study demonstrated 3D-2D target registration error of 2.5 mm (1.5 mm IQR), and the method was robust over a large dose range, down to 5 [Formula: see text]Gy/frame (an order of magnitude lower than the nominal fluoroscopic dose). The clinical feasibility study demonstrated accurate registration with both preoperative and intraoperative radiographs, yielding 3.1 mm (1.0 mm IQR) projection distance error with robust performance for FOV ranging from 340 × 340 mm2 to 170 × 170 mm2 (at the image plane). The method demonstrated accurate estimation of the target reduction pose in simulation, phantom, and a clinical feasibility study for a broad range of dislocation patterns, initialization error, dose levels, and FOV size. The system provides a novel means of guidance and assessment of pelvic reduction from routinely acquired preoperative CT and intraoperative fluoroscopy. The method has the potential to reduce radiation dose by minimizing trial-and-error and to improve outcomes by guiding more accurate reduction of joint dislocations.

Early failure of symphysis pubis plating

INTRODUCTION

Operative fixation of a disrupted symphysis pubis helps return alignment and stability to a traumatized pelvic ring. Implant loosening or failure has been demonstrated to commonly occur at some subacute point during the postoperative period. The purpose of this study is to report on a series of patients with traumatic pelvic ring disruptions to determine the incidence and common factors associated with early postoperative symphyseal plate failure before 7 weeks.

MATERIALS AND METHODS

126 patients retrospectively identified with unstable pelvic injuries treated with open reduction and plate fixation of the symphysis pubis and iliosacral screw fixation. Preoperative and postoperative radiographs, computed tomography (CT) images, and medical chart were reviewed to determine symphyseal displacement preoperatively and postoperatively, time until plate failure, patient symptoms and symphyseal displacement at failure, subsequent symphyseal displacement, incidence of additional surgery, and patient weight bearing compliance.

RESULTS

14 patients (11.1%) sustained premature postoperative fixation failure. 13 patients had anteroposterior compression (APC)-II injuries and 1 patient had an APC-III injury. Preoperative symphyseal displacement was 35.6 millimeters (mm) (20.8-52.9). Postoperative symphyseal space measurement was 6.3mm (4.7-9.3). Time until plate failure was 29days (5-47). Nine patients (64.2%) noted a pop surrounding the time of failure. Symphyseal space measurement at failure was 12.4mm (5.6-20.5). All patients demonstrated additional symphyseal displacement averaging 2.6mm (0.2-9.4). Two patients (14.2%) underwent revision. Four patients (28.5%) were non-compliant.

CONCLUSION

Premature failure of symphysis pubis plating is not uncommon. In this series, further symphyseal displacement after plate failure was not substantial. The presence of acute symphyseal plate failure alone may not be an absolute indication for revision surgery. Making patient education a priority could lead to decreased postoperative non-compliance and potentially a decreased incidence of implant failure. Posterior pelvic ring fixation aides overall pelvic ring stability and may help minimize further displacement after early postoperative symphyseal plate failure. Further functional outcome and biomechanical studies surrounding early symphyseal plate failure are needed.

The Irish experience of Symphysiotomy: 40 years onwards

The art of symphysiotomy for delivery in the instance of cephalopelvic disproportion has been a dying art since the advent of caesarean section but in Ireland this surgical procedure was not abolished until 1992. This practice is still present in the developing world and in some circumstances used in developed countries. This study offers some insights on the 40-year follow-up of patients who had undergone symphysiotomy.

Radiological analysis, operative management and functional outcome of open book pelvic lesions: a 13-year cohort study

We present the clinical and radiological outcome of a 13-year cohort study of 38 open book pelvic lesions. All patients were treated in one Level I Trauma centre. In the posterior pelvis, sacro-iliac diastasis was seen in 31 patients, sacral fracture in 7. In all patients with sacro-iliac diastasis, the pubic bone was inferiorly displaced on the primary ap pelvic overview on the side of injury. All but one patient was treated with open reduction and internal fixation of the symphysis pubis. Additional stabilization of the posterior pelvis was done in 9 patients. 32 patients were seen after a median follow up of 84 months. Majeed score and SF-36 questionnaire were used. Functional outcome was excellent with a mean Majeed score of 95.7. Comparing our data with the SF-36 score of the normal German population, the mean value of the 'role-physical' and the 'physical function' categories was significantly lower for patients treated with an open book lesion. There was a tendency towards a better outcome in open book lesions with sacral fracture. There was a tendency towards worse outcome for the patients with additional dorsal stabilization. Male impotence was the single most important lesion of neurological origin which persisted two years after open book lesion.

CONCLUSION

Functional outcome after surgical treatment of open book pelvic lesions is good. External rotation and accompanying inferior displacement of the ipsilateral hemipelvis may be a sign of partial lesion of the posterior sacroiliac complex. Identification of patients who need additional posterior stabilization remains difficult.

Management outcomes in pubic diastasis: our experience with 19 patients

Background

Pubic diastasis, a result of high energy antero-posterior compression (APC) injury, has been managed based on the Young and Burguess classification system. The mode of fixation in APC II injury has, however, been a subject of controversy and some authors have proposed a need to address the issue of partial breach of the posterior pelvic ring elements in these injuries.

Methods

The study included a total of 19 patients with pubic diastasis managed by us from May 2006 to December 2007. There was a single patient with type I APC injury who treated conservatively. Type II APC injuries (13 patients) were treated surgically with symphyseal plating using single anterior/superior plates or double perpendicularly placed plates. Type III injuries (5 patients) in addition underwent posterior fixation using plates or percutaneous sacro-iliac screws. The outcome was assessed clinically (Majeed score) and radiologically.

Results

The mean follow-up was for 2.9 years (6 months to 4.5 years). Among the 13 patients with APC II injuries, the clinical scores were excellent in one (7.6%), good in 6 (46.15%), fair in 4 (30.76%) and poor in 2 (15.38%). Radiological scores were excellent in 2 (15.38%), good in 8 (61.53%), fair in 2 (15.38%) and poor in one patient (7.6%). Among the 5 patients with APC III injuries, there were 2 patients each with good (50%) and fair (50%) clinical scores while one patient was lost on long term follow up. The radiological outcomes were also similar in these. Complications included implant failure in 3 patients, postoperative infection in 2 patients, deep venous thrombosis in one patient and bladder herniation in one of the patients with implant failure.

Conclusions

There is no observed dissimilarity in outcomes between isolated anterior and combined symphyseal (perpendicular) plating techniques in APC II injuries. Single anterior symphyseal plating along with posterior stabilisation provides a stable fixation in type III APC injuries. Limited dissection ensuring adequate intactness of rectus sheath is important to avoid long term post-operative complications.

Saddle-horn injury of the pelvis. The injury, its outcomes, and associated male sexual dysfunction

BACKGROUND

A saddle-horn injury of the pelvis occurs when a horse rider is thrown into the air and then falls back, with the perineum coming into contact with the saddle or saddle horn. The purpose of this study was to evaluate the characteristics and clinical outcomes, including sexual dysfunction, of this injury.

METHODS

We conducted a retrospective review of a consecutive series of male patients who had a saddle-horn injury of the pelvis after being bucked from a horse. Clinical and radiographic results were assessed more than eighteen months after the injury. Functional outcome measures were evaluated at the time of the latest follow-up with use of visual analog pain scales, a questionnaire addressing occupational and recreational function, the International Index of Erectile Function instrument, the Iowa pelvic score, and the Short Form-36.

RESULTS

Twenty patients were assessed at an average of thirty-three months after the injury. Seventeen patients had returned to riding horses, and ten felt that they had returned to their previous level of recreation, which had been "heavy" in nine cases and "moderate" in one. Eighteen patients had returned to their previous employment. Eighteen patients were found to have sexual dysfunction at the time of the latest follow-up. The mean Iowa pelvic score was 84 points (range, 56 to 99 points). The Short Form-36 outcomes scores were diminished in two subsections, role physical and role emotional, compared with population norms.

CONCLUSIONS

Mild pain can be expected after saddle-horn injury despite successful surgical treatment, and the injury does not preclude a return to previous employment or riding horses. A high proportion of men experience erectile dysfunction, which is unlikely to respond well to pharmacologic therapy.

External fixation of pubic symphysis diastasis from postpartum trauma

Pubic symphysis diastasis is recognized as a possible complication of pregnancy. When this occurs, pubic symphysis diastasis may cause anterior widening and loss of stiffness within the pubic symphysis, causing potential instability in the pubic joint. The persistent loss of reduction can cause substantial disability in postpartum women. Pubic symphysis diastasis has previously been treated conservatively using a pelvic girdle and bedrest with some success. When a diastasis >3 cm is present, however, surgical intervention may be needed to preserve the integrity of the pubic symphysis joint. To date, most surgical procedures for reduction of pubic symphysis diastasis have been via internal fixation with plates and screws on the superior pubic rami. Although internal fixation provides good structural support, this method would be inadequate if a postpartum pubic symphysis diastasis patient has significant reproductive organ damage, due to the risk of soft tissue infection or osteomyelitis. External fixation is an alternate method of pubic symphysis diastasis treatment that has not received significant attention in the literature to date. We present the following case report to highlight a novel use of a pelvic frame external fixator for treatment of a severe postpartum pubic symphysis diastasis with organ damage. This article outlines a treatment alternative to internal fixation for cases of pubic symphysis diastasis with a contaminated pelvic environment.

Urethral injury as a complication of isolated diastasis pubis: case report

Diastasis of the symphysis pubis is typically associated with straddle-type pelvic trauma. A case of diastasis pubis due to a recreational water-ski accident is described here. This case is complicated with a partial urethral rupture.