Ultrasonography in Early Diagnosis of Heterotopic Ossification

High Frequency Spectral Ultrasound Imaging Detects Early Heterotopic Ossification in Rodents

Heterotopic ossification (HO) is a devastating condition in which ectopic bone forms inappropriately in soft tissues following traumatic injuries and orthopedic surgeries as a result of aberrant mesenchymal progenitor cell (MPC) differentiation. HO leads to chronic pain, decreased range of motion, and an overall decrease in quality of life. While several treatments have shown promise in animal models, all must be given during early stages of formation. Methods for early determination of whether and where endochondral ossification/soft tissue mineralization (HO anlagen) develop are lacking. At-risk patients are not identified sufficiently early in the process of MPC differentiation and soft tissue endochondral ossification for potential treatments to be effective. Hence, a critical need exists to develop technologies capable of detecting HO anlagen soon after trauma, when treatments are most effective. In this study, we investigate high frequency spectral ultrasound imaging (SUSI) as a noninvasive strategy to identify HO anlagen at early time points after injury. We show that by determining quantitative parameters based on tissue organization and structure, SUSI identifies HO anlagen as early as 1-week postinjury in a mouse model of burn/tenotomy and 3 days postinjury in a rat model of blast/amputation. We analyze single cell RNA sequencing profiles of the MPCs responsible for HO formation and show that the early tissue changes detected by SUSI match chondrogenic and osteogenic gene expression in this population. SUSI identifies sites of soft tissue endochondral ossification at early stages of HO formation so that effective intervention can be targeted when and where it is needed following trauma-induced injury. Furthermore, we characterize the chondrogenic to osteogenic transition that occurs in the MPCs during HO formation and correlate gene expression to SUSI detection of the HO anlagen.

Heterotopic Ossification Following Upper Extremity Injury

Heterotopic ossification (HO) presents a substantial barrier to rehabilitation for patients with severe burns or trauma. Although surgical excision is a mainstay of management for this condition, this is unable to address the chronic sequelae of HO, including chronic pain, joint contractures, nerve dysfunction, and open wounds. Current therapeutic modalities are aimed at excision and the prevention of recurrence using nonsteroidal antiinflammatory drugs (NSAIDs) or radiation therapy. Research is now focused on identifying alternative strategies to prevent the initial occurrence of HO through NSAIDs and novel inhibitors of the bone morphogenetic protein signaling pathway.

Nyka W. Neurogenic heterotopic ossifi cation – case study

The authors presented the case of a 30-year-old man in whom sudden cardiac arrest occurred as a result of high voltage electric shock. Starting from the 2nd week after the accident, rehabilitation was carried out in hospital conditions, designed to maintain range of motion in the joints, and from the 6th week, intensive rehabilitation was performed at the patient’s home. Despite the implemented treatment, total mobility restriction was observed in the hip joints, and based on spatial projection radiography and a CT, the patient was diagnosed with massive neurogenic heterotopic ossifi cation (NHO). Two surgeries were performed to remove the NHO: fi rst, from the left area (15th month after the accident), and then the right hip joint (18th month following the accident). After the intervention there was a signifi cant increase in mobility of both hips and a decrease in pain, which resulted in signifi cantly improved functional capabilities of the patient. In addition, prophylaxis to prevent the recurrence of NHO was implemented in order to maintain both passive and active range of motion, and the use of physical therapy treatments in the form of deep oscillation were performed. The results of the CT conducted in the 41st month following the accident revealed lesser NHO than the originally diagnosed. Rolka Ł., Browiński D., Kwiatek-Rolka K., Sielska M., Sielski G., Nyka W.M. Neurogenic heterotopic ossification – case study. Med Rehabil 2016; 20(4): 22-27. DOI: 10.5604/01.3001.0009.5482

Multimodality imaging review of the post-amputation stump pain

Limb amputation is one of the oldest known surgical procedures performed for a variety of indications. Little surgical technical improvements have been made since the first procedure, but perioperative and post-operative refinements have occurred over time. Post-amputation pain (PAP) of the stump is a common complication but is an extremely challenging condition to treat. Imaging allows early diagnosis of the underlying cause so that timely intervention is possible to minimize physical disability with its possible psychological and socioeconomic implications. A multidisciplinary approach should be taken involving the rehabilitation medicine team, surgeon, prosthetist, occupational therapist and social workers. Conventional radiographs demonstrate the osseous origin of PAP while high-resolution ultrasound is preferred to assess soft-tissue abnormalities. These are often the first-line investigations. MRI remains as a problem-solving tool when clinical and imaging findings are equivocal. This article aimed to raise a clear understanding of common pathologies expected in the assessment of PAP. A selection of multimodality images from our Specialist Mobility and Rehabilitation Unit are presented so that radiologists are aware of and recognize the spectrum of pathological conditions involving the amputation stump. These include but are not limited to aggressive bone spurs, heterotopic ossification, soft-tissue inflammation (stump bursitis), collection, nervosas, osteomyelitis etc. The role of the radiologist in reaching the diagnosis early is vital so that appropriate treatment can be instituted to limit long-term disability. The panel of authors hopes this article helps readers identify the spectrum of pathological conditions involving the post-amputation stump by recognizing the imaging features of the abnormalities in different imaging modalities.