Various materials have been proposed for cranial reconstruction. Bone autograft and alloplasts such as polymethylmethacrylate (PMMA) and hydroxyapatite (HA) cement are most commonly used at the present time. Patients submitted for cranioplasty were evaluated. The prognostic factors influencing the results and the outcome were analyzed. Three hundred twelve patients who had 449 procedures performed by a single surgeon to reconstruct a calvarial deformity between 1981 and 2001 were studied. Post-tumor resection deformity was the main reason for cranioplasty (32.4%). Bone graft was the material of choice (69.5%). The main surgical site was the frontal bone (53.2%). Complications were observed in 23.6% of cases and were responsible for the least satisfactory results (P > 0.001), with infection and material exposure being the most critical complications. The eventual outcome was considered good in 91.8% of cases. The use of HA cement was associated with the worst results (P > 0.001). Bone grafts showed a high grade of partial resorption and required further surgery for correction. Multiple surgical procedures were correlated with a high rate of complications and an unsatisfactory outcome. Bone graft and PMMA are still the best materials in calvarial reconstruction. Even though HA cement is an osteoconductive material, it seems to induce what appears to be an immunoguided delayed inflammatory reaction that leads to thinning of the skin and exposure of the material, making secondary repair difficult. Before deciding which reconstructive option to use, a careful evaluation of the patient in terms of diagnosis, number of previous surgeries, and surgical site should be undertaken. If this is adopted, good results and a satisfactory outcome can be achieved on long-term follow-up.

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Biomaterial research and tissue engineering have guided new developments in bone replacement. In this study, the osteoconductive and osteoinductive properties of 45S5 Bioglass (Novabone-C/M, Porex Surg., Newnan, GA), granules as a bone replacement material for large calvarial defects were evaluated. Rabbit periosteal cells were expanded in culture and used in vivo. Alkaline-phosphatase assay, collagen type I, and calcium expression were applied to confirm osteoblast phenotype. In the in vivo phase, a 15-mm diameter critical size calvarial defect was created in rabbits (n = 14). The defect was reconstructed according to four treatment groups: autogenous bone (n = 2), Bioglass alone (n = 2), Bioglass + bone (n = 5), Bioglass + periosteal cells (n = 5). The animals were killed 12 weeks after surgery, and the samples were analyzed. Periosteal cells grew successfully in vitro. Because of their fast proliferation and potential to differentiate into osteoblasts, they were an excellent source of cells for bone tissue engineering. The best ossification was seen when autogenous bone was used (79.4% ossified), whereas only 8.2% of the defect in the Bioglass group showed ossification. Addition of bone or cells to the Bioglass increased the area of ossification to 42.7% and 30.2%, respectively. Defects replaced with Bioglass showed varying degrees of inflammatory reaction because of the intense cell-mediated biodegradation process. Based on these findings, the use of Bioglass granules to repair large craniofacial defects cannot be advised.

Swelling and congestion of flaps are frequently seen postoperatively and can cause unexpected necrosis. According to previous reports, venous thrombosis seems to be a more frequent problem than arterial occlusion in both experimental and clinical surgery. Few satisfactory venous trauma models exist, and reports on experimental venous thrombosis are rare. The object of this study was to create a rabbit venous occlusion flap model and to evaluate the effect of low-molecular-weight heparin on this flap. Eight New Zealand rabbits were used in the pilot study, in which the ideal congested flap was investigated using a flap pedicle based on the central auricular artery with a skin pedicle 0, 1, 2, or 3 cm wide. The flap (3 x 6 cm) was designed on the central part of the left ear, and the central auricular vein and nerve, the former for venous return, were cut out at the base of the flap. The flaps with skin pedicles 0, 1, 2, or 3 cm wide showed mean necrosis length of 60.0, 9.3, 4.2, and 0.0 mm, respectively. The flaps with skin pedicles 0, 1, 2, or 3 cm wide showed mean necrosis of 100, 15.5, 7, and 0 percent, respectively. Therefore, the flap, based on a 1-cm-wide skin pedicle and the central auricular artery, was selected as an optimal congested flap model showing 15.5 percent necrosis. The congested flap was then elevated on the left ear of another 10 rabbits. Subcutaneous low-molecular-weight heparin (320 IU/kg) was administered immediately after surgery to five of the rabbits (the low-molecular-weight heparin group), and the remaining five were used as a control group. Fluorescein was injected 15 minutes after surgery to evaluate the circulatory territory of the flap, and the circulatory territory was measured 5 minutes after injection. The flaps were assessed 7 days after surgery by angiography, histology, and clinical findings. The circulatory territory was significantly greater in the low-molecular-weight heparin group (mean +/- SD, 39.2 +/- 3.0 mm) than the control group (mean +/- SD, 48.0 +/- 1.0 mm) (p< 0.001) assessed 7 days after surgery. The longest flap survival length in group A and group B ranged from 40 to 55 mm (mean +/- SD. 49.4 +/- 5.6 mm) and complete survival (mean +/- SD, 60.0 +/- 0.0 mm). The improvement in survival was statistically significant for group B compared with group A (p < 0.015). Histologic evaluation revealed moderate to severe venous congestion and inflammation in the control group, whereas there were minimal changes in the low-molecular-weight heparin group. Angiography of the flap revealed obvious venous occlusion in the periphery in the control group compared with the low-molecular-weight heparin group. The authors conclude that subcutaneous administration of low-molecular-weight heparin has a great potential to improve the survival length of a congested flap without major complications.

Fractures of the orbital floor often need to be reconstructed with rigid materials that provide a stable orbital floor and reestablish the correct orbital volume.

In head and neck reconstruction, there is sometimes the need for a skin flap lined with mucosa. The object of this study was to determine whether small pieces of mucosa grafted onto the undersurface of a skin flap can be expanded in a reasonable time to provide the material required to reconstruct a full-thickness cheek defect as a free flap. The study consisted of two phases: prelamination and expansion of the flap, and vascularized free-tissue transfer of the flap. Six adult mongrel dogs were used. First, a 5 x 10-cm flap based on the saphenous vessels was elevated on the lower leg, and then four 1 x 2-cm pieces of mucosa harvested from the tongue were grafted onto the undersurface of the flap. A tissue expander (5 x 10 cm) was then placed under the flap, and the incision was closed primarily. The expanders were initially filled with just enough normal saline to obliterate dead space immediately after surgery. The expansion was continued twice weekly for 3 weeks until sufficient expansion was obtained. Two of six flaps were followed for an additional 6 weeks after the 3-week expansion period to observe whether additional mucosa could be obtained. After measurement of the mucosal area, each flap was transferred as free flap to reconstruct an iatrogenic cheek defect. The increase of mucosal surface area was compared with the original graft, and differences were analyzed using the paired t test. All flaps were successfully expanded without any complications. Histologic evaluation revealed that grafted mucosa took well without evidence of graft necrosis, and the intergraft area was covered with histiocytes. Angiography revealed well-defined vascular structures covering the entire area of the flap. The new mucosal area (23.5 +/- 2.4 cm2) was significantly larger than the original mucosal graft (8.7 +/- 0.9 cm2) (p < 0.001). The net increase of the mucosal area was 172.9 +/- 32.4 percent. The increase of mucosal area in two flaps, following a 6-week consolidation period after 3 weeks of expansion, was only slightly greater (25.9 +/- 1.3 cm2) than those without the consolidation period (22.3 +/- 1.8 cm2). This increase of the mucosal area appears to be related to the amount of expansion, and not to the length of the consolidation period. The flaps were successfully transferred as free flaps to reconstruct the full-thickness cheek defects without major complications. Although a staged operation to allow flaps to mature is needed, the present procedure has the advantages of providing a mucosa-lined flap and allowing primary closure of the donor site. The authors conclude that expansion of this flap has great potential in reconstructive surgery.

Closed sinus lifting is a unique technique in being simple and less invasive (Summers, Compendium 15(6):698, 1994). However, it is blind to assess the safety of sinus lining during lifting without perforation. Previously, sinus membrane was assessed endoscopically in an invasive way. We aimed to judge clinically the sinus membrane integrity after crestal elevation by a direct simple less invasive endoscopic visual assessment through the crestal osteotomy site. To confirm undetected perforation, the sinus membrane was monitored dynamically by introducing the endoscope through a trephined opening in the lateral wall of the sinus (Nkenke et al., Int J Oral Maxillofac Implants 17(4):557–66, 2002).PatientsTwelve patients suffering atrophic posterior maxillae ranging 3–5 mm bone height below the sinus membrane were included to perform closed sinus lifting with simultaneous immediate implant placement under direct endoscopic assessment.ResultsThe floor was lifted without perforation in 83.33% of cases. However, it varied according to its thickness. Minor perforations occurred in two cases (16.67%). Both perforations were detected from the crestal endoscopic view while one of them was detected from the lateral endoscopic approach.ConclusionCrestal endoscopic access gives better direct vision to the membrane than the induced opening in the lateral wall of the maxillary sinus. Moreover, it uses the same prepared osteotomy site without doing any extra procedures. Perforation depends on the thickness of sinus lining and its ability to stretch during elevation. Intact crestal sinus floor elevation can never be guaranteed under endoscopic monitoring especially with thin irregular membranes.

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