BACKGROUND: Peripheral ossifying fibroma is a nonneoplastic inflammatory hyperplasia that originates in the periodontal ligament or periosteum in response to chronic mechanical irritation. Peripheral ossifying fibroma develops more commonly in young females as a solitary, slow-growing, exophytic nodular mass of the gingiva, no more than 2 cm in diameter. While various synonyms have been used to refer to peripheral ossifying fibroma, very similar names have also been applied to neoplastic diseases that are pathologically distinct from peripheral ossifying fibroma, causing considerable nomenclatural confusion. Herein, we report our experience with an unusual giant peripheral ossifying fibroma with a differential diagnostic challenge in distinguishing it from a malignancy.
METHODS: A 68-year-old Japanese male was referred to our department with a suspected gingival malignancy presenting with an elastic hard, pedunculated, exophytic mass 60 mm in diameter in the right maxillary gingiva. In addition to computed tomography showing extensive bone destruction in the right maxillary alveolus, positron emission tomography with computed tomography revealed fluorodeoxyglucose hyperaccumulation in the gingival lesion. Although these clinical findings were highly suggestive of malignancy, repeated preoperative biopsies showed no evidence of malignancy. Since even intraoperative frozen histological examination revealed no malignancy, surgical resection was performed in the form of partial maxillectomy for benign disease, followed by thorough curettage of the surrounding granulation tissue and alveolar bone. Histologically, the excised mass consisted primarily of a fibrous component with sparse proliferation of atypical fibroblast-like cells, partly comprising ossification, leading to a final diagnosis of peripheral ossifying fibroma. No relapse was observed at the 10-month follow-up.
CONCLUSIONS: The clinical presentation of giant peripheral ossifying fibromas can make the differential diagnosis from malignancy difficult. Proper diagnosis relies on recognition of the characteristic histopathology and identification of the underlying chronic mechanical stimuli, while successful treatment mandates complete excision of the lesion and optimization of oral hygiene. Complicated terminological issues associated with peripheral ossifying fibroma require appropriate interpretation and sufficient awareness of the disease names to avoid diagnostic confusion and provide optimal management.

Ultrasound (US) can visualize the periosteal changes in the early stage compared to radiography. In this review, we studied periosteal manifestations on US and assessed their diagnostic utility for osteomyelitis (OM) and arthritis. We included articles that studied ultrasonographic findings of periosteal changes in OM and arthropathies with aims to systematically review periosteal manifestations of each condition and summarize diagnostic values of each finding. A total of 13 articles were included in the systematic review. Of these, 10 articles are on OM, 3 articles are on psoriatic arthritis (PsA), 1 article is on rheumatoid arthritis (RA), and 1 article is on gouty arthritis (GA). In OM, subperiosteal fluid/subperiosteal collection (SF/SC) was detected in 32%-76% within 72 h after presentation. Periosteal reaction (PR) was seen after day 4 and the sensitivity on US ranges from 33% to 100%. In PsA, PR was seen near 16%-59% in active PsA joints. Periosteal changes are rarely detected in RA joints. Small hyperechoic spots were seen in 87.5% of GA. SF/SC may be seen on US as the earliest sign followed by PR for OM. PR is more specific in PsA than RA. Further investigations on periosteal abnormalities on US are warranted to confirm our findings.

Background  Periostitis ossificans (PO) are rare, benign ossifying surface lesions characterized by the centripetal ossification with osseous and soft-tissue edema. Their clinicoradiological appearances can easily mimic those of more sinister or infective surface lesion. Objective  This study aimed to explore the various anatomical locations and muscle attachment at the site of PO, and evaluate the role of complementary image findings in patients presenting at our tertiary orthopaedic referral center. Patients and Methods  A retrospective review of our oncology and radiology databases was undertaken to identify patients with PO reported on radiographs, magnetic resonance imaging (MRI) and computed tomography (CT) over the past 13 years (2007-2020). Patient demographics, sites of PO, muscle attachment at the site of PO, findings on complementary imaging, and clinical management outcome were documented. Results We identified 38 patients with PO with a mean age of 24 years (range: 4-66 years). Muscle attachment was seen at the site of PO in the majority of cases (89%). The majority of PO were in the lower limb and commonly seen around the attachment of quadriceps. Deltoid attachment was commonly involved in the upper limb. Conclusion  Muscle attachment is commonly seen at the site of PO, which results in stripping of the periosteum resulting in soft-tissue and osseous edema and centripetal ossification.

BACKGROUND: Chronic subdural hematoma (CSDH) is a relatively common disease, especially in the elderly, for which there is no clear standard of treatment available. The authors systematically evaluated the efficacy of various surgical procedures for the treatment of chronic subdural hematoma.
METHODS: Electronic databases of PubMed, EmBase, Web of Science, Medicine, and the Cochrane Library were searched systematically. Based on the PRISMA template, we finally selected and analyzed 13 eligible papers to evaluate the effect of different drainage methods on CSDH. The primary outcomes were recurrence and clinical outcomes. Secondary outcomes were mortality and postoperative complications and other parameters.
RESULTS: The meta-analysis included 3 randomized controlled trials and 10 retrospective studies (non-randomized controlled trials) involving 3619 patients. The pooled results showed no statistically significant difference between non-subdural drainage (NSD) and subdural drainage (SD) in mortality and complication rates (P > 0.05). Additionally, overall pooled results showed that the use of NSD (10.9%) has a lower recurrence rate than the use of SD (11.7%), but the results were not statistically significant (relative risk ratio [RR] = 0.98; 95% confidence interval [CI] = 0.70-1.45; I2 = 47%; P = .92). However, the difference between NSD and SD in postoperative bleeding rate reached statistical significance (RR = 2.39; 95% CI = 1.31-4.36; I2 = 0 %; P = .004). Subgroup analysis showed that SD was associated with similar recurrent CSDH (RR = 0.75; 95% CI = 0.52-1.09; I2 = 0%; P = .14), good recovery (RR = 0.98; 95% CI = 0.93-1.04; I2 = 0%; P = .50), and mortality (RR = 0.98; 95% CI = 0.37-2.57; I2 = 0%; P = .96), compared to NSD.
CONCLUSIONS: These results suggest that NSD and SD are equally effective in the treatment of patients with CSDH, with no difference in final clinical characteristics and radiologic outcomes. However, in patients with limited subdural space after evacuation of a hematoma, NSD may be the preferred strategy to avoid iatrogenic brain injury.

The periosteum is a thin layer of connective tissue covering bone. It is an essential component for bone development and fracture healing. There has been considerable research exploring the application of the periosteum in bone regeneration since the 19th century. An increasing number of studies are focusing on periosteal progenitor cells found within the periosteum and the use of hydrogels as scaffold materials for periosteum engineering and guided bone development. Here, we provide an overview of the research investigating the use of the periosteum for bone repair, with consideration given to the anatomy and function of the periosteum, the importance of the cambium layer, the culture of periosteal progenitor cells, periosteum-induced ossification, periosteal perfusion, periosteum engineering, scaffold vascularization, and hydrogel-based synthetic periostea.

BACKGROUND: Periosteum-mediated bone regeneration (PMBR) is a recognized method for mandibular reconstruction. Despite its unpredictable nature and the limited degree to which it is understood, it does not share the concerns of developmental changes to donor and recipient tissues that other treatment options do. The definitive role of the periosteum in bone regeneration in any mammal remains largely unexplored. The purpose of this study was to identify the genetic determinants of PMBR in mammals through a systematic review.
METHODS: Our search methodology was designed in accordance with the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines. We conducted a quality assessment of each publication, and evaluated the differences in gene expression between days 7 and 15.
RESULTS: A total of four studies satisfied the inclusion criteria. The subjects and tissues examined in these studies were Wistar rat calvaria in two studies, mini-pigs in one study, and calves and mice in one study. Three out of the four studies achieved the necessary quality score of ≥ 3. Gene expression analysis showed increased activity of genes responsible for angiogenesis, cytokine activities, and immune-inflammatory responses on day 7. Additionally, genes related to skeletal development and signaling pathways were upregulated on day 15. Conclusions: The results suggest that skeletal morphogenesis is regulated by genes associated with skeletal development, and the gene expression patterns of PMBR may be characterized by specific pathways.

The role of periosteum rich in a variety of bone cells and growth factors in the treatment of bone defects has gradually been discovered. However, due to the limited number of healthy transplantable periosteum, there are still major challenges in the clinical treatment of critical-size bone defects. Various techniques for preparing biomimetic periosteal scaffolds that are similar in composition and structure to natural periosteal scaffold have gradually emerged. This article reviews the current preparation methods of biomimetic periosteal scaffolds based on various biomaterials, which are mainly divided into natural periosteal materials and various polymer biomaterials. Several preparation methods of biomimetic periosteal scaffolds with different principles are listed, their strengths and weaknesses are also discussed. It aims to provide a more systematic perspective for the preparation of biomimetic periosteal scaffolds in the future.

Bone marrow stromal cells (BMSCs) and periosteum-derived cells (PDCs) represent promising skeletal stem cell sources to treat critical-size bone defects. However, the large number of preclinical tests with a variety of in vivo data complicates the selection of cells for further clinical translation. This systematic review aims to analyze the in vivo bone-forming efficacy of BMSCs- and PDCs-based approaches in all published preclinical experiments until November 2020. For this purpose, four databases (PubMed, Embase, Cochrane Central Register of Controlled Trial, and Web of Science) were searched for eligible literature, which yielded a total of 94 full-text articles for systematic review. This review generated an evidence-based list of BMSC- or PDC-based approaches, which have been evaluated for bone formation in different animal models. Among them, 74 studies were included for pairwise and network meta-analysis. The results revealed that both PDC and BMSC had beneficial bone-forming efficacy compared to bare scaffold. In addition, BMSC- and PDC-based approaches had no significant difference regarding in vivo bone-forming efficacy. However, BMSC-based approach had a higher probability to be ranked better than PDC-based approach. Furthermore, the review discusses (i) the possible risk of bias of the in vivo evaluation of cell-based approaches, (ii) the difficulty in replication of such experiments due to frequent poor reporting of the methods and results, and (iii) the clinical relevance of the currently utilized BMSC- and PDC-based approaches. Systematic review registration: The study was prospectively registered in PROSPERO, Registration No. CRD42021270922.

Here we review the knowledge on the local biological immunological response (formation of \"pseudo periosteum\" of the host) to two types of nonresorbable membranes used in the horizontal and vertical alveolar ridge augmentation: the titanium-reinforced polytetrafluoroethylene membrane and the titanium mesh membrane. A literature search was conducted including available in vitro, in vivo, and clinical studies on cellular and molecular immunological response to these two types of nonresorbable membranes, in particular the formation of \"pseudo periosteum\".

A systematic treatment plan and an appropriate selection of surgical technique are the critical requirements for an effective closure of oroantral fistula (OAF). A 45-year-old female patient had sinus opening after she underwent a surgical tooth extraction 20 years back. On her frequent visits to the dentists some attempts were made for closure including surgical intervention, only for the lesion to return back. Computerized tomography (CT) scan was taken to rule out any bony extension of a lesion, the CT revealed a 1 × 1 cm radiolucency with a through - through communication from the alveolar bone to the right maxillary sinus because of the bony defect in the floor of maxillary sinus along with thickening of the maxillary sinus lining. The closure of the defect was done by a lateral pedicle flap raised from the right side was elevated and laterally slid to cover the defect without tension and was sutured with 4-0 resorbable interrupted suture while maintaining a bare surgical bed covered by the periosteum and a thin layer of connective tissue. This technique provides immediate repair of the defect to the patient, and also maintains comparatively normal anatomic architecture to the oral cavity. Eight months postoperative follow-up revealed a complete closure of OAF without any complications. The findings of this case suggest that lateral sliding pedicle flap can be a conservative approach in managing a long-standing OAF.