Pubic and ischial sarcoidosis: a single bone lesion

Bone sarcoidosis is very rarely indicative of the disease. When bone lesion is associated with lung and lymph node involvement, diagnosis can be made based on clinical and imaging features. When bone lesion is isolated, it is difficult to differentiate it from bone metastases because they both have similar appearance in imaging : in this case, the diagnosis is made by bone biopsy with histological study. We report the case of a 61-year-old male with a lytic lesion of the right ischio pubic ramus which appears to be aggressive whose biopsy revealed bone sarcoidosis.

The morphological mapping of lateral compression type 1 pelvic fracture and pelvic ring stability classification: a finite element analysis

Purpose This finite element analysis assessed lateral compression (LC-1) fracture stability using machine learning for morphological mapping and classification of pelvic ring stability. Methods Computed tomography (CT) files of LC-1 pelvic fractures were collected. After morphological mapping and producing matrix data, we used K-means clustering in unsupervised machine learning to classify the fractures. Based on these subtypes, we manually added fracture lines in ANSYS software. Finally, we performed a finite element analysis of a normal pelvis and eight fracture subtypes based on von Mises stress and total deformation changes. Results A total of 218 consecutive cases were analyzed. According to the three main factors—zone of sacral injury and completion, pubic ramus injury side, and the sagittal rotation of the injured hemipelvis—the LC-1 injuries were classified into eight subtypes (I–VIII). No significant differences in stress or deformation were observed between unilateral and bilateral public ramus fractures. Subtypes VI and VIII showed the maximum stress while subtypes V–VIII showed the maximum deformation in the total pelvis and sacrum. The subtypes did not differ in superior public ramus deformation. Conclusions Complete fracture of sacrum zones 2/3 may be a feature of unstable LC-1 fractures. Surgeons should give surgical strategies for subtypes V–VIII.

Intraosseous schwannoma of inferior pubic ramus – A rare benign osseous neoplasm

Intraosseous schwannomas are a very rare subgroup of schwannomas. They account for <1% of all primary bone neoplasms. The mandible is the most commonly involved bone followed by the sacrum. We herein report a case of intraosseous schwannoma involving the inferior ramus and body of the pubic bone in a 43-year-old male who presented with a swelling in the right groin. On radiographs and computed tomography, it appeared as a mildly expansile, lytic, multiloculated lesion in the right pubic bone with a narrow zone of transition, sclerotic margins with areas of cortical breach, and a significant intra and extrapelvic soft-tissue component which did not show any areas of calcification. On magnetic resonance imaging, it appeared isointense to skeletal muscle on T1-weighted images, mildly hyperintense on T2-weighted images, and markedly hyperintense on short-tau inversion recovery images. The differentials considered on imaging were chondroid neoplasms such as chondromyxoid fibroma or low-grade chondrosarcoma, giant cell tumor, and plasmacytoma. However, biopsy and histopathology revealed an intraosseous schwannoma. The patient was operated and the lesion was excised in toto. Intraoperatively, the origin of the lesion was identified as the right obturator nerve. Post-operative, the patient recovery was uneventful and he was discharged.

Irreducible Overlapping Pubic Symphysis Dislocation Managed with Distraction Osteotomy of the Contralateral Superior Pubic Ramus: A Rare Case Report

Introduction: Overlapping pubic symphysis dislocation (OPSD) or a locked pubic symphysis is a compression of the pelvic ring with the intact pubis trapped into the contralateral obturator foramen. Reduction can be difficult and contralateral suprapubic osteotomy is a good way to address the irreducible OPSD. The technique has only been discussed thrice in the available literature. Case Report: We report the case of a 26-year-old man who had his right pubic ramus entrapped within the contralateral obturator foramen, having an overlap of >4 cm with associated ipsilateral sacroiliac joint (SI joint) disruption and urethral injury. When all the maneuvers of closed and instrumented open reduction failed, we performed a superior pubic ramus osteotomy on the left side and unlocked the incarcerated right pubic ramus. The osteotomy site was stabilized with a 6-hole recon plate and SI joint was stabilized with a 6.5mm percutaneous sacroiliac screw. The patient underwent delayed urethral repair at 10 weeks after the index surgery. At 3-year follow-up, the patient did not report any pubic discomfort, urinary and sexual problems. Conclusion: Locked OPSD is a rare injury and is frequently associated with sacroiliac and urethral injuries. Distraction osteotomy of the contralateral superior pubic ramus is a viable option for irreducible cases. Keywords: Lateral compression injury, locked symphysis pubis, superior pubic ramus osteotomy, overlapping pubic symphysis dislocation.

Recurrent Atraumatic Pelvic Fractures in a Patient With Cushing’s Disease - Is DEXA Scan Really Useful to Predict the Future Fracture Risk?

Background: Cushing’s disease may present with a variety of clinical features, including osteoporosis and fracture. Due to the inhibitory effects of cortisol on osteoblastic activity and enhancing effects on osteoclastic activity, these patients are more prone to have osteoporotic fractures. We report a case of ACTH dependent Cushing’s disease presenting with recurrent atraumatic pelvic fractures in a woman despite normal bone mineral density for her age. Clinical Case: A 56 year-old-woman was referred to the endocrinology department for suspected Cushing’s syndrome following a recent atraumatic fracture of right pubic ramus. She had a history of weight gain and easy fatigue. On examination, she had subtle changes suggestive of Cushing’s syndrome, including mild truncal obesity, minimal bruising and moon face. She had been taking hormone replacement therapy for 3 years for the post-menopausal symptoms. Her bone mineral density was normal for her age on a recent DEXA scan [femoral neck T score: -0.9, Z score: 0.1, lumbar spine (L1-L4) T score: -1.2, Z score: -0.1]. Her vitamin D, serum calcium and parathyroid hormone levels were normal. Her 24-hour urinary cortisol was 688 nmol/day (reference range: &lt;200 nmol/day), low dose dexamethasone suppression cortisol 525 nmol/L (reference range: &lt;50 nmol/day), ACTH 96 ng/L (reference range: &lt;50 ng/L), indicating ACTH dependent Cushing syndrome. MRI pituitary showed 7 mm right sided hypoenhancing area suggestive of a pituitary microadenoma. CT neck, thorax, abdomen and pelvis did not show any source of ectopic ACTH secretion but did show generalised osteopenia, with old fractures of the ribs and left ilium. She was referred for trans-sphenoidal resection of pituitary tumour. While awaiting pituitary surgery she was treated with metyrapone: at this time she suffered a further atraumatic fracture of the left pubic ramus. Conclusion: Glucocorticoid excess predominantly affects trabecular bones (pelvis, ribs, lumbar spine) as compared to cortical bones. Due to micro-architectural changes, reduction in bone strength is disproportionately greater than would be expected from BMD measured by DEXA. Clinicians should be aware that recurrent fracture of trabecular bones may indicate Cushing’s disease even though other clinical features of cortisol excess are minimal or absent.

3D PRINTING PREOPERATIVE PLANNING AND CUSTOMIZED SURGICAL GUIDES ASSOCIATED WITH O-ARM NAVIGATION SYSTEM FOR MULTIPLANAR OSTEOTOMY OF COMPLEX PELVIC DEFORMITY

INTRODUCTION 3D printing technology is penetrating the healthcare field at an astonishing rate. The reduction of its costs, makes it more accessible to everyone. MATERIAL AND METHODS 35-year-old woman who had functional limitation in her right hip due to pelvic ring fracture in her childhood. She had dysmetria of lower limbs and femoral anteversion of 40 degrees. Imaging tests showed vicious consolidation of the right hemipelvis associated with antero-medial displacement. RESULTS Preoperative, we performed her 3D printing pelvic ring model. Osteotomies were digital planned (iliac crest, superior pubic ramus, incomplete of inferior pubic ramus, and semicircular of posterior column) and also how many degrees we would need for rotation the osteotomized fragment. Posterior column osteotomy was the most difficult, so we designed 3D surgical printing cutting guide able to being inserted into the iliac fossa. We used it to introduced four Kirschnner wires that leads us as a guide to avoid the greater sciatic notch. O-arm navigation system helped us make sure to achieve more precision. 3D printing pelvic ring model was sterilized to pre-contouring osteosynthesis plates. After two years of follow-up, good functional results were observed, without gait claudication either limb dysmetria. Her range of motion is 105 degrees of hip flexion, 20 degrees of internal hip rotation and 40 degrees of external hip rotation. Complete radiological consolidation was observed. CONCLUSION Digital planning and 3D printing technology allows to improve three-dimensional compression of bone pathology leading to a higher likelihood of a predictable ideal outcome compared to conventional techniques.

Unusual Case of Pelvic Osteomyelitis Revealing Osteoporosis

Pelvic osteomyelitis is an uncommon and challenging condition to treat. Pressure ulcers, spinal injuries, contiguous sources of tracking infections, pelvic surgical procedures, traumatic injuries and open fractures all serve as nidi for developing pelvic osteomyelitis. We present a case of pelvic osteomyelitis suspected to be caused by insufficiency fractures due to osteoporosis in an anorexic adult.51 year old postmenopausal Caucasian female with undiagnosed anorexia presented to the hospital for severe right-sided pelvic pain and nausea. She denied fevers, vomiting, trauma, surgical procedures, history of pelvic infections, abnormal vaginal discharge, travel, prolonged steroid therapy. She disclosed a strict vegetarian diet, excessive daily exercise, low dairy intake and over 100lb intentional weight loss over the past 30 years. She reported normal menses, used oral contraceptives between ages of 25 to 30, and reached menopause at 49 years. For many years, she denied medical care including age-appropriate cancer screenings. She is employed in academia and denies tobacco, alcohol or drug use. On admission, height 153cm and weight 43kg, BMI 16.7kg/m2. Examination was notable for frail body habitus, moderate RLQ and pelvic tenderness, prominent PSIS and SI joints with decreased RLE range of motion. Laboratory results showed calcium 9.5mg/dL (n 8.6–10.4), phosphorus 4.1mg/dL (2.5–4.5), ALP 181IU/L (45–115), PTH 23pg/dL (n 9–76), Vitamin D 35ng/dL (n 25–80), 24-hour urinary calcium 285mg/24h (n 50–400). Abdominopelvic CT scan showed chronic right pubic ramus and bilateral sacral insufficiency fractures confirmed on MRI with septic arthritis of the pubic symphysis, osteomyelitis of pubic bodies and intramuscular abscess extending to the right adductor muscle. Wound culture was positive for Streptococcus viridans and pelvic bone biopsy showed degenerative changes. The patient completed IV Ceftriaxone therapy and underwent DXA scan confirming osteoporosis (T-scores:-3.8 lumbar spine L1-L4, -3.6 left femoral neck, -3.3 right femoral neck). Alendronate 10mg daily and calcium citrate-vitamin D 1000mg-800IU twice daily was prescribed. Diagnostic workup for secondary causes of severe osteoporosis was unremarkable except for hypercalciuria, for which calcium supplement was held with a plan to repeat in the future. Concern for her cachectic appearance and severity of her illness also elicited a dietician referral. Pelvic osteomyelitis and septic arthritis are seldom found without inciting insults. We report an atypical cause of presumed anorexia induced osteoporosis resulting in pelvic osteomyelitis. Untreated osteoporosis may lead to fracture, resulting in inflammation and predisposing patients to infections. Thus, early recognition and evaluation of osteoporosis in patients at high risk for fracture, such as patients with anorexia, is critical for prevention.

The Impact of an Open-Book Pelvic Ring Injury on Bone Strain: Validation of a Finite Element Model and Analysis Within the Gait Cycle

The threshold for surgical stabilization for an open-book pelvic fracture is not well defined. The purpose of this research was to validate the biomechanical behavior of a specimen-specific pelvic finite element (FE) model with an open-book fracture with the biomechanical behavior of a cadaveric pelvis in double leg stance configuration under physiologic loading, and to utilize the validated model to compare open book versus intact strain patterns during gait. A cadaveric pelvis was experimentally tested under compressive loading in double leg stance, intact, and with a simulated open-book fracture. An intact FE model of this specimen was reanalyzed with an equivalent simulated open-book fracture. Comparison of the FE generated and experimentally measured strains yielded an R2 value of 0.92 for the open-book fracture configuration. Strain patterns in the intact and fractured models were compared throughout the gait cycle. In double leg stance and heel-strike/heel-off models, tensile strains decreased, especially in the pubic ramus contralateral to the injury, and compressive strains increased in the sacroiliac region of the injured side. In the midstance/midswing gait configuration, higher tensile and compressive FE strains were observed on the midstance side of the fractured versus intact model and decreased along the superior and inferior pubic rami and ischium, with midswing side strains reduced almost to zero in the fractured model. Identified in silico patterns align with clinical understanding of open-book fracture pathology suggesting future potential of FE models to quantify instability and optimize fixation strategies.