Pre-surgical CT-assessment of neurogenic myositis ossificans of the hip and risk factors of recurrence: a series of 101 consecutive patients

Neurogenic heterotopic ossification of the hip: Magnetic resonance imaging versus computed tomography for pre-surgical assessment

PURPOSE

Neurogenic heterotopic ossification (NHO) of the hip is a frequent complication of spinal cord injuries, often requiring surgical management. Pre-surgical imaging assessment is essential, usually with computed tomography (CT)-scan. We aimed to compare magnetic resonance imaging (MRI) and CT for pre-surgical imaging assessment of the NHO, particularly for their relationships with vessels and nerves.

METHOD

This prospective study included consecutive patients who underwent surgery for NHO from July 2019 to April 2022. All patients had CT angiography and MRI including Zero Echo Time and TRICKS sequences. Radiologists used standardized reports for CT and MRI to evaluate NHO and their features, bone mineralization, and relation to the arteries, veins and nerves. Agreement between pre-surgical CT and MRI was evaluated.

RESULTS

Twenty-four patients (mean age: 53.5 ± 12.2 years) were included, among which 7 had bilateral NHO (31 hips). NHO were anterior in 15/31 hips (48 %), multifragmented in 25/31 hips (81 %). Mild and significant demineralization was most frequent. Gutter and tunnel were reported in 11.1 % of the arteries. Nerves were more often identified in MRI than in CT-scan. Agreement coefficients between CT and MRI were excellent for NHO location (0.95) and implantation (0.92), good for fragmentation (0.70), contact with joint capsule (0.66), bone mineralization (0.74), and relation to arteries (0.85), veins (0.76), sciatic nerve (0.7) and moderate for femoral nerve (0.47).

CONCLUSION

MRI exhibited a good agreement with CT for pre-surgical assessment of NHO of the hip, especially to evaluate their relationships with the arteries, veins and sciatic nerve. Femoral nerves were more often identified in MRI than in CT-scan.

Heterotopic ossification and COVID 19: Imaging analysis of ten consecutive cases

PURPOSE

Heterotopic ossification (HO) is defined by the formation of mature lamellar bone in periarticular soft tissue due to prolonged immobility. This study aimed to explore the imaging features of HOs in immobilized COVID-19 patients compared to other causes previously described in the literature.

METHOD

This retrospective single centre study included patients with severe COVID-19 hospitalized in intensive care unit (ICU) with mechanical ventilation and affected by HOs between March 2020 and December 2021. Two radiologists reviewed imaging features of biphasic CT-scans using a standardized template including morphological findings and anatomical relationship of the HO with the joint, vessels and nerves.

RESULTS

10 COVID-19 patients with 19 analyzed HOs following ICU hospitalization were including. Biphasic CT imaging characteristics were analyzed. The hips were the most commonly affected joint (n = 14/19; 74%). The distribution was mainly posterior (n = 7/19; 38%). HOs were located away from main arteries. No case of severe demineralization was observed. Capsular disruption was observed for three HOs (n = 3/19; 16%). One patient presented concomitant venous thrombosis ipsilateral to the HO. CT-scan demonstrated neural involvement of the sciatic nerve in 3 patients with HO (n = 3/19; 16%).

CONCLUSION

Severe COVID-19 patients with a biphasic CT imaging presented HO mainly located around the hips, with rare vessel and nerve invasion and no severe demineralization. Some features such as a lower level of local invasion differ from HOs related to other disorders as described in the literature whereas morphological aspects are similar.

Neurogenic heterotopic ossificans of hips in a case of expanded dengue syndrome following critical illness polyneuropathy

We present a case of 71-year-old man with bilateral hip neurogenic heterotopic ossificans following critical illness polyneuropathy as a complication of expanded dengue syndrome. His left hip was stiff and showed a circumferential ossific mass. After initial medical management, the patient underwent excision of ossific mass using posterior approach. For adequate excision, femoral head and neck were resected and a hybrid total hip arthroplasty was performed. The patient was followed up for 2 years and showed good clinical outcome without recurrence of heterotopic ossification. This case highlights the rare aetiology of neurogenic heterotopic ossification which is critical illness polyneuropathy following expanded dengue syndrome. It highlights that adequate resection and a total hip arthroplasty can be a viable option in selected cases of circumferential heterotopic ossification in old individuals.

Impact of Heterotopic Ossification on Functional Recovery in Acute Spinal Cord Injury

Objective: In spinal cord injury (SCI), heterotopic ossification is a frequent secondary complication, commonly associated with limited range of motion of affected joints, which could lead to secondary disability in activities of daily living. Additionally, heterotopic ossifications might challenge the effect of regeneration-promoting therapies on neurological and functional recovery. This study evaluated the impact of heterotopic ossification on clinical recovery within the first year after SCI.

Methods: The study was conducted as a monocentric longitudinal paired cohort study. Recruitment was based on consecutive sampling in the framework of the European Multicenter about Spinal Cord Injury (EMSCI). Recovery profiles were determined using standardized neurological and functional clinical assessments within the 1st year following SCI. All study participants underwent at least two comprehensive standardized neurological and functional clinical examinations according to the International Standards for Neurological Classification of SCI and the Spinal Cord Independence Measure, respectively. Data regarding the diagnosis and treatment of heterotopic ossification were obtained by reviewing the patient medical records. The most similar “digital twin” from the entire EMSCI database were matched in terms of age, acute neurological and functional status to each individual with SCI, and heterotopic ossification.

Results: Out of 25 participants diagnosed with heterotopic ossification, 13 individuals were enrolled and matched to control individuals. Most individuals presented with motor complete injury (75%). Ossifications were most frequently located at the hip joints (92%) and mainly occurred within the first 3 months after SCI. Individuals with heterotopic ossification achieved around 40% less functional improvement over time compared to their matched counterparts, whereas neurological recovery was not altered in individuals with SCI and heterotopic ossification.

Conclusion: Heterotopic ossification—a common complication of SCI—unfavorably affects functional recovery, which in the end is most relevant for the best possible degree of independence in activities of daily living. Upon presentation with heterotopic ossification, neurological improvement achieved through potential restorative therapies might not translate into clinically meaningful functional improvement. Diagnostic algorithms and effective early prevention/treatment options for heterotopic ossification need to be established to ensure the best possible functional outcome.

Clinical Trial Registration: NCT01571531 (https://clinicaltrials.gov).

Comparison of magnetic resonance imaging and computed tomography for bone assessment of neurogenic heterotopic ossification of the hip: a preliminary study

Background

Neurogenic heterotopic ossification (NHO) is a frequent complication, often involving the hip. The functional impact may require surgical management and pre-surgical imaging assessment is necessary, usually by computed tomography (CT). We aimed to compare the performances of magnetic resonance imaging (MRI) and CT for bone assessment on pre-surgical imaging of the heterotopic ossifications and their features in NHO of the hip.

Methods

This single-center prospective preliminary study included all patients who underwent surgery for NHO with joint limitation from July 2019 to March 2020. All patients had a CT after biphasic iodinated solution injection and an MRI including T1-weighted, STIR and ZTE sequences. Standardized reports were completed for both exams for each patient, evaluating location, implantation and fragmentation of NHO, relation to the joint capsule and bone mineralization, then were compared.

Results

Seven patients from 32 to 70 years old (mean = 50.2 ± 17.2 years) were evaluated. NHO were bilateral in 2 patients, for a total of nine hips: six right hips and three left hips. Observed concordance rates between MRI and CT were, respectively, 94.4% for location, 100% for circumferential extension, 87.3% for implantation 88.9% for fragmentation, 77.8% for relation to the joint capsule and 66.7% for bone mineralization. It was 100% for femoral neck fracture and osteonecrosis of the femoral head.

Conclusion

This preliminary study suggests that pre-surgical MRI imaging should be considered as effective as CT for bone assessment of NHO and their features.

Trial registration: ClinicalTrials.gov, NCT03832556. Registered February 6, 2019, https://clinicaltrials.gov/ct2/show/NCT03832556.

The Surgical Management of the Rare Neurogenic Myositis Ossificans of the Hip: A Report of 3 Cases

Introduction:

Myositis ossificans (MO) is a benign non-neoplastic condition in which heterotopic bone formation occurs in soft tissues. Neurogenic MO is one variant of MO where the lesion is a result of neurological disorders, including brain and spinal cord injuries, especially when followed by immobility and spasticity. MO can also be a result of direct trauma or even genetic mutations.

Case Report:

We present three cases of young men (16, 37, and 22-year-old) who developed MO of the hip joint following brain or spinal cord injuries. One of them had also sustained a direct trauma to the affected hip joint at the time of the accident. All three patients presented with inability to walk independently due to diminished range of motion at the affected joint. X-rays and computerized tomography (CT) scans with 3-dimentional (3D) reconstruction suggested the diagnosis of MO, but the serum alkaline phosphatase was within normal limits at the time of presentation. The first case had bilateral involvement with unmistakable separation between the heterotopic bone formation and the frank hip joints on CT. This patient underwent successful staged excision of the ossifications. The second patient had unilateral hip joint involvement with the absence of clear separation between the heterotopic bone formation and the hip joint, thus, underwent total hip replacement for the affected side as excision was not possible. The third patienthad unilateral hip joint involvement and underwent excision of the ossification with dynamic hip screw insertion after sustaining a stable intertrochanteric fracture intraoperatively. Postoperatively, all three patients received physiotherapy and oral indomethacin. Upon recovery, they were able to walk independently with a near-normal range of motion at the hip joint. There was no evidence of recurrence upon follow-up visits, and CT scans in patients I and II. Follow-ups for patient III were not possible as the patient died 1 month after surgery due to pulmonary embolism.

Conclusion:

The surgical management of MO is indicated when non-operative methods fail to provide an adequate range of motion around the hip joint. Pre-operative assessment utilizing 3D-CT scans proved to be essential in dictating the appropriate surgical approach. During post-operative follow-ups, the physiotherapy and oral indomethacin provided additional improvement in outcome and patients’ satisfaction.

Ankylosing Neurogenic Myositis Ossificans of the Hip: A Case Series and Review of Literature

Purpose

Neurogenic myositis ossificans (NMO) in patients with traumatic spinal cord or brain injuries can cause severe joint ankylosis or compromise neurovascularture. The purpose of this study was to evaluate the clinical and radiological outcomes of and review considerations relevant to surgical resection of NMO of the hip joint.

Materials and Methods

Six patients (9 hips) underwent periarticular NMO resection between 2015 and 2017. The medical records of these patients were retrospectively reviewed. Preoperative computed tomography including angiography was performed to determine osteoma location and size. Improvement in hip motion allowing sitting was considered the sole indicator of a successful surgery. The anterior approach was used in all patients. The ranges of motion (ROM) before and after surgery were compared.

Results

The mean time from accident to surgery was 3.6 years. Average ROM improved from 24.3°(flexion and extension) to 98.5°(flexion and extension) after surgery, and improvement was maintained at the last follow-up. No commom complications (e.g., deep infection, severe hematoma, deep vein thrombosis) occurred in any patient. Improvement in ROM in one hip in which surgical resection was performed 10 years after the accident was not satisfactory owing to the pathologic changes in the joint.

Conclusion

Surgical excision of periarticular NMO of the hip joint can yield satisfactory results, provided that appropriate preoperative evaluation is performed. Early surgical intervention yields satisfactory results and may prevent the development of intra-articular pathology.