Langerhans Cell Histiocytosis in the Pediatric Population: Treatment of Isolated Craniofacial Lesions.

Langerhans cell histiocytosis (LCH) commonly affects the craniofacial skeleton and prognosis depends on location, extension, and recurrence of the disease. The aim of our study is to better define the treatment of single craniofacial lesions, as to date different treatment modalities have been suggested and recurrence rates for both unifocal and multifocal bony lesion range between 10% and 70%. Between 2000 and 2014, we retrospectively reviewed clinical findings, anatomic location, extent of the disease, therapy, and outcomes in 24 pediatric patients with histologically confirmed LCH. Seventeen patients (67%) had craniofacial involvement, of which 13 had single system involvement and 4 had multisystem involvement. Eight patients (33%) had no craniofacial involvement. Eleven patients affected by unifocal cranial lesions were treated with resection and reconstruction. One patient with a unifocal mastoid lesion was treated with chemotherapy alone (vinblastine and prednisone). Four patients with mandible lesions were treated with curettage alone.There were no recurrences in patients treated with excision alone. One patient (25%) treated with curettage recurred. Two patients with diffuse disease manifested organ dysfunction and diabetes insipidus. Chemotherapy was tolerated in 12 patients treated.Our findings suggest that resection of isolated LCH lesions of the cranium is safe and chemotherapy is effective and well tolerated for nonsurgical cases.

Dental implants placed in severely atrophic jaws reconstructed with autogenous calvarium, bovine bone mineral, and collagen membranes: A 3- to 19-year retrospective follow-up study.

OBJECTIVES: To present the clinical, radiographic, and patient-related outcomes of patients presenting with severely resorbed ridges reconstructed with autogenous calvarial bone blocks and rehabilitated with implant-supported prostheses. MATERIAL AND METHODS: From 1998 to 2014, 72 patients presenting with severe bone defects were reconstructed with autogenous calvarial bone blocks covered with bovine bone mineral granules and collagen membranes. Four to 9 months later, 330 implants were placed and loaded 3-9 months later. The follow-up ranged from 3 to 19 years (mean: 8.1 years). The following parameters were recorded: (a) complication rate of the reconstructive procedure; (b) bone resorption before implant placement; (c) implant survival rate and implant-related complications; (d) peri-implant bone resorption; and (e) patient's satisfaction inquired with a dedicated questionnaire. RESULTS: No patients developed severe complications, such as complete loss or resorption of the grafts. A dehiscence occurred in six patients, which developed a mild graft resorption. The mean peri-implant bone resorption before implant placement was 0.13 mm (SD ± 0.71). All patients received the planned number of implants. Three patients were lost during the follow-up. The survival rate of implants at the end of the observation period was 98.5%. The mean peri-implant bone resorption ranged from 0.00 to 4.87 mm (mean: 1.11 mm). At last, 90% of the patients were very satisfied as regards the treatment received. CONCLUSIONS: Results from this study suggested that: (a) bone volume in the areas reconstructed with calvarial grafts was stable over time; (b) survival rates of implants were consistent with those reported for implants placed in native bone; (c) patient's satisfaction was high.

Influence of Platelet-Poor Plasma on Angiogenesis and Maintenance of Volume in Autogenous Bone Grafts.

PURPOSE: The aim of this study was to evaluate the effect of different storage media on angiogenesis and maintaining autogenous bone graft volume in rabbits. MATERIAL AND METHODS: Two grafts were removed bilaterally from the calvaria of 18 rabbits. One graft was removed and immediately fixed in the right mandibular angle (control group). The other graft was stored for 30 minutes in 1 of the following storage media (n = 6): saline solution (saline group), air exposure (dry group), or platelet-poor plasma (PPP group) and then retained by a screw in the right mandibular angle in the same animal. Four weeks later the animals were euthanized, and the grafted areas were harvested, fixed in 10% phosphate buffered formaldehyde solution, and embedded in paraffin. The 5-µm semi-serial sections were stained in hematoxylin and eosin and Mallory trichrome. RESULTS: Histologic analysis of all groups showed the bone graft was vascularized and well incorporated into the recipient site. The number of blood vessels decreased in the saline and dry groups compared with the control group (P < .03); in contrast, the number of blood vessels increased in the PPP group (P < .05). There were fewer osteoclasts in the saline group compared with the control group (P < .05). Furthermore, the saline group showed larger numbers of blood vessels than the dry group (P < .01). The PPP group showed larger bone graft volumes compared with the dry and saline groups (P < .01). In addition, the saline group showed larger bone graft volumes than the dry group (P < .01). CONCLUSIONS: PPP improved angiogenesis, maintained the volume of the autogenous bone graft, and was a better storage medium during the trans-surgical period than the dry and saline media.

Reconstruction of frontal defects with calvarial grafts.

BACKGROUND: There are many options for the reconstruction of frontal sinus wall defect resulting from injury, neoplastic lesions and aesthetic deformities. These mainly include autogenous grafts, allogenous grafts, and alloplastic materials. The aim of the present study is to report the advantages of using autogenous calvarial bone grafts over other reconstruction techniques, in the reconstruction of frontal defects. METHODS: We describe 16 consecutive cases of anterior frontal sinus defects between 2004 and 2015, in which calvarial bone grafts were used. Medical records were retrospectively analysed to evaluate graft survival. RESULTS: Bone defects were caused by injury (3), aesthetic deformities (2), external frontal sinus surgeries (2), tumours (6: three osteomas, two fibrous dysplasias, one squamous cell carcinoma), and osteomyelitis (3). There were no significant complications during harvesting, and morbidity was minimal. Furthermore, at one and five-year follow-up, no graft resorption or rejection was noted, and cosmetic results were satisfactory. CONCLUSIONS: Our results indicate that calvarial bone graft is an appropriate material to use in anterior frontal sinus reconstruction.

Vital Bone Formation After Grafting of Autogenous Bone and Biphasic Calcium Phosphate Bioceramic in Extraction Sockets of Rats: Histological, Histometric, and Immunohistochemical Evaluation.

PURPOSE: The study aimed to investigate through histology, histometry, and immunohistochemistry the vital bone formation after grafting of biphasic calcium phosphate bioceramic (BC) in combination with calvarial autogenous bone into the dental sockets of rats. MATERIALS AND METHODS: Forty-five male rats were submitted to upper right incisor extraction and divided according to the grafted material in: control, bioceramic (BC), and bioceramic + autogenous bone (BC + AB). The animals were killed 7, 21, and 42 days after surgery for histological, histometric, and immunohistochemistry analysis. RESULTS: Histomorphometric results demonstrated, for BC + AB group, formation of trabecular bone between the particles of BCs and autogenous bone, connecting them, as well as higher percentage of vital bone in comparison with BC. Immunohistochemical reactions showed intense labeling for Runx2-positive cells in the group BC + AB. CONCLUSIONS: Autogenous bone was able to stimulate bone turnover enabling a larger amount of vital bone synthesis and can be recommended as a viable grafting material in combination with synthetic biphasic BC.

Healing at the interface between recipient sites and autologous block bone grafts affixed by either position or lag screw methods: a histomorphometric study in rabbits.

OBJECTIVE: To compare the sequential healing at the interface gap occurring between autologous bone grafts and recipient sites using two types of fixation techniques. MATERIAL AND METHODS: Twenty-four adult male New Zealand white rabbits were used. Two bone grafts were collected from the calvaria and secured to the lateral aspect of the angle of mandible in each animal. Cortical perforations at the recipient sites were performed. However, no modifications were applied to the graft for its adaptation to the recipient site. Two types of fixation techniques by position or lag screws were applied. This was done by preparing osteotomy holes smaller or larger than the screw diameter, respectively. The animals were sacrificed after 3, 7, 20, and 40 days. RESULTS: After 3 days, the distance between the graft and the recipient site was similar between the two different fixations. Due to the anatomical shapes of the recipient sites and grafts, the distance between the two parts was lower in the central region (<0.1 mm) compared to the external regions of the graft (0.5-0.6 mm). The first evidence of small amounts of new (woven) bone was seen after 7 days, forming from the parent bone. The percentage increased after 20 and 40 days. After 40 days, the grafts were well incorporated within the recipient sites in both groups without any statistically significant difference. CONCLUSIONS: The present study did not show superiority of one method over another. A fixation to a recipient site with perforations may be sufficient for incorporating an autologous bone graft even if its adaptation is not perfect and irrespectively of the fixation method. Distances of approximately half millimeter were bridged with newly formed bone.

Reconstruction of the severely atrophic edentulous maxillae with calvarial bone grafts.

OBJECTIVES: Treatment of the severely atrophic maxilla with dental implants is challenging due to the insufficient horizontal and vertical bone volume and centripetal resorption pattern of the maxilla. Bone-augmentation procedures are often necessary prior to implant placement. The objective of this study was to assess the suitability of using calvarial bone grafts to enable implant placement in severely atrophic maxillae. MATERIAL AND METHODS: Seventeen patients with severe atrophic edentulous maxillae were reconstructed with autogenous calvarial bone grafts. After a 4-month healing period, the patients received a total of 134 dental implants, which were left to heal in submerged positions for 3 months before prosthetic rehabilitation was performed. Patients were followed clinically and radiographically for an average observation period of 53.94 months. RESULTS: At the intraoral recipient sites, two infections developed, causing partial loss of the respective bone grafts. Implant placement, however, was possible at all sites. No donor-site complications occurred. Two of 134 implants were lost in two patients prior to prosthetic loading. The implant survival rate was 98.51%. The implant success rate was 87.6%, and a mean marginal bone loss of 0.62 mm (SD 0.77 mm) was documented. CONCLUSIONS: Patients with severe bone atrophy of the edentulous maxilla can be successfully reconstructed with calvarial bone grafts and dental implants and show a stable clinical and radiographic situation after a mean observation period of 53 months.

Single-staged vs. two-staged implant placement in vertically deficient alveolar ridges using bone ring technique - Part 2: implant osseointegration.

OBJECTIVES: The aim of this study was to evaluate the osseointegration of implants placed in a single-staged compared to two-staged procedure using bone ring technique. MATERIAL AND METHODS: In this study were used standardized, vertical alveolar bone defects in dogs. In the test group, dental implants (Straumann BL® , Basel, Switzerland) were inserted simultaneously with bone ring technique. As control group served implants inserted 6 months following grafting. Implants of both groups were left for an osseointegration period of 3 and 6 months. The peri-implant bone loss and bone-to-implant contact within the bone ring and native bone were analyzed morphometrically. An explorative statistical analysis was performed. RESULTS: The peri-implant bone level remained relatively stable within groups and between groups per given time period. Most of bone apposite on the implant surface in two groups was composed of newly formed bone. A nonparametric analysis of variance (ANOVA) revealed no significant advantage for two-staged implant placement for new and total bone, except for residual bone (P = .0084). Furthermore, two groups of implants performed similarly in bone ring and in native bone throughout the observation period. CONCLUSIONS: In terms of osseointegration, both techniques are likely equally efficient in the present defect model. The single-staged implant placement with cortical bone grafts warrants further documentation in clinical studies.

Single-staged vs. two-staged implant placement using bone ring technique in vertically deficient alveolar ridges - Part 1: histomorphometric and micro-CT analysis.

BACKGROUND: Simultaneous implant placement with bone grafting shortens the overall treatment period, but might lead to the peri-implant bone loss or even implant failure. The aim of this study was to compare the single-staged to two-staged implant placement using the bone ring technique. MATERIAL AND METHODS: Four standardized alveolar bone defects were made in the mandibles of nine dogs. Dental implants (Straumann BL® , Basel, Switzerland) were inserted simultaneously with bone ring technique in test group and after 6 months of healing period in control group. Animals of both groups were euthanized at 3 and 6 months of osseointegration period. The harvested samples were analyzed by means of histology and micro-CT. RESULTS: The amount of residual bone decreased while the amount of new bone increased up to 9 months of healing period. All morphometric parameters remained stable between 3 and 6 months of osseointegration period within groups. Per a given time point, median area of residual bone graft was higher in test group and area of new bone in control group. The volume of bone ring was greater in test than in control group, reaching the significance at 6 months of osseointegration period (P = 0.002). CONCLUSIONS: In the present type of bone defect, single-staged implant placement may be potentially useful to shorten an overall treatment period.

Resorbable Construct for Subtotal Cranial Vault Remodeling.

INTRODUCTION: Pansynostosis can result in markedly thin calvarial bone resulting in poor quality and quantity of allograft for cranial vault expansion. Such scenarios can result in large calvarial defects and poorly stabilized constructs. Additionally, the osteoinductive properties of neonatal dura and paracranium in cranial vault reconstruction suggest the possibility of reconstructing extensive calvarial defects using minimal native calvarium given the appropriate scaffold. We report a case of subtotal cranial vault remodeling involving greater than 50% of the cranial vault using a custom poly DL lactic acid (Sonic Weld) resorbable plate construct and underlay calvarial bone grafting. METHODS: A 4-month-old male infant presented with a diagnosis of Cruzon syndrome and pansynostosis. Staged reconstruction was performed with the initial stage involving the posterior and middle cranial vault. Given the severity of the deformity, the native cranial bone was thinned with multiple defects such that it could not be used to provide structural integrity or sufficient surface coverage for cranial vault reconstruction. Useable bone comprised only a fraction of the surface area required to expand the posterior and midcranium. Resorbable poly DL lactic acid (Sonic Weld) plates were used to create a custom construct for reconstruction of the posterior and middle cranial vault. The construct was then seeded with usable fragments of the native calvarium and secured to the cranial base with resorbable pins. RESULTS: The construct resulted in maintained cranial shape throughout the postoperative period. Postoperative computed tomography imaging demonstrated osteogenesis throughout the construct with bridging of the fragmented calvarial grafts. Examination of the construct during anterior cranial vault remodeling demonstrated near complete resorption of the construct, stable posterior cranial vault, and minimal dural adhesions to the posterior cranium. At 11 months postoperatively, the patient continues to demonstrate appropriate cranial expansion and maintenance of posterior cranial shape. CONCLUSIONS: Fully resorbable constructs can provide effective structural support and a scaffold for osteogenisis in conjunction with minimal native calvarial bone grafts during reconstruction of large cranial vault defects in the infantile period.