Differential osteopontin expression in human osteoblasts derived from iliac crest and alveolar bone and its role in early stages of angiogenesis.

In our previous study, we revealed significant differences of osteopontin (OPN) gene expression in primary human osteoblasts (HOBs) derived from iliac crest bone (iHOBs) and alveolar bone (aHOBs). The present study aims at assigning this discriminative expression to a possible biologic function. OPN is known to be involved in several pathologic and physiologic processes, among others angiogenesis. Therefore, we studied the reaction of human umbilical vein endothelial cells (HUVECs) to HOB-derived OPN regarding angiogenesis. To this end, human primary explant cultures of both bone entities from ten donors were established. Subsequent transcription analysis detected higher gene expression of OPN in iHOBs compared to aHOBs, thereby confirming the results of our previous study. This difference was particularly apparent when cultures were derived from female donors. Hence, OPN protein expression as well as the angiogenic potential of OPN was analyzed, originating from HOBs of one female donor. In accordance to the gene expression level, secreted OPN was more abundant in the supernatant of iHOBs than in aHOBs. Moreover, secreted OPN was found to stimulate migration of HUVECs, but not proliferation or tube formation. These results indicate an involvement in very early stages of angiogenesis and a functional distinction of OPN from HOBs derived from different bone entities.

Evaluation of long-term functional donor-site morbidity after deep circumflex iliac crest artery bone flap harvest.

PURPOSE: Free flap surgery can be associated with donor-site morbidity. The purpose of this study was to analyze long-term functional outcomes at the donor site after deep circumflex iliac artery (DCIA) bone flap harvesting. METHODS: Fourteen patients (8 men and 6 women, mean age 53.9 years; range 22-87 years) with mandible resection (8 carcinomas, 4 ameloblastomas, 1 osteonecrosis, and 1 myxofibroma) and DCIA flap reconstruction were included in an observational study. Ranges of motion in the hip and lumbar spine, Harris hip score (HHS), jumping mechanography, chair rising, and balance testing were performed on a ground force reaction plate (Leonardo Mechanograph, Novotec Medical GmbH, Germany). The primary outcome was the Esslinger fitness index (EFI, maximum peak power in W/kg normalized to age and gender). RESULTS: Functional assessment was performed preoperatively and 29.0 months postoperatively (range 12-51 months). Mean DCIA flap length was 6.3 cm (range 3.3-10.1 cm). Jaw reconstruction was successful in all cases. HHS (99.2 vs. 97.7 points, P = .004) and all ranges of motion in the lumbar spine and hip joint except for dorsal extension were significantly reduced postoperatively (range -4° to -11.0°). There was no significant difference between pre- and postoperative EFI (77.9% vs. 74.28%, P = .591) and body sway (1.25 cm2 vs. 2.01 cm2 , P = .806). Sensory deficits (n = 5), load dependent pain (n = 3), and limitations of daily activities (n = 3) were subjective complaints. CONCLUSION: Functional donor site morbidity after DCIA harvesting can be expected to be low in the long-term.

Translating Computer-Aided Design and Surgical Planning Into Successful Mandibular Reconstruction Using a Vascularized Iliac-Crest Flap.

PURPOSE: This study evaluated the computer-aided approach to the reconstruction of mandibular defects using a vascularized iliac-crest flap. MATERIALS AND METHODS: From December 2015 to October 2016, 14 patients (8 men and 6 women) 18 to 64 years old (median age, 29 yr) were treated at the Peking University School and Stomatology Hospital (Beijing, China). Biopsy specimens from all patients were subjected to histologic examination before segmental mandibulectomy. Computer-based surgical techniques, including virtual surgical planning, computer-aided design and manufacturing, rapid prototyping, and intraoperative navigation, were used to restore the anatomic continuity and configuration of the mandible using a vascularized iliac-crest flap. Two transverse dimensions and 1 anteroposterior (A-P) dimension were evaluated based on the virtual plan and postoperative computed tomogram. Lines from condylar head to condylar head and from gonial angle to gonial angle were defined as the transverse dimensions. A perpendicular line drawn from the mandibular midline to the center point on the condylar head to condylar head measurement was defined as the A-P dimension. Complications were evaluated during follow-up. RESULTS: The flap success rate was 92.9% (13 of 14), with 1 flap failure. After the operation, there were no other serious complications in 13 of the 14 patients, who exhibited a good mandibular configuration with good occlusion. Furthermore, the height of bone graft was sufficient for implants. Healing of the recipient and donor sites with no serious complication was uneventful. The average surgical errors in the A-P dimension and transverse dimensions were 1.8 ± 1.0 mm (range, 0.2 to 3.7 mm), 2.2 ± 1.1 mm (range, 0.9 to 5.0 mm), and 2.6 ± 1.6 mm (range, 0.3 to 7.2 mm), respectively. CONCLUSIONS: The use of these digital techniques was found to be a viable option for reconstruction of mandibular defects, but the results should be interpreted cautiously because of the small number of patients and the relatively short follow-up.

Nonvascularized bone grafts: how successful are they in reconstruction of segmental mandibular defects?

OBJECTIVE: Segmental mandibular defects can occur due to various etiologies, including trauma and tumor resection. Reconstruction should provide adequate support for subsequent dental rehabilitation and allow for proper occlusion. Nonvascularized bone grafts have been used for reconstructing mandibular defects in cases where vascularized grafts were not feasible. The objective of this study was to assess the success rate of these grafts in reconstruction of segmental defects of various sizes in the mandible. STUDY DESIGN: Fifty patients were included in this retrospective chart review. Length of the grafts varied from 3 to 20 cm and patients were followed up from 4 to 80 months. Fifteen grafts were harvested from anterior iliac crest, 23 from posterior iliac crest, 9 grafts were a combination of either with costochondral graft, and 3 were solely allografts. Bone morphogenetic protein was utilized in 41 cases as an adjunct. RESULTS: Success was defined as continuity of bone clinically and radiographically at a 4-month follow-up. Nonvascularized bone grafting was successful in 90% of cases. Complications were observed in 34% of cases, of which the most common were infection followed by wound dehiscence. CONCLUSIONS: Our study demonstrated substantial success rate with nonvascularized bone grafts in reconstruction of segmental mandibular defects.

Mandibular reconstruction using an iliac bone flap with perforator-supported external oblique abdominal muscle island: a pilot study.

The deep circumflex iliac artery (DCIA) flap is one of the bone flaps commonly used for mandibular reconstruction. Observation of the skin paddle and Doppler ultrasound are methods that are usually used to monitor DCIA flaps after mandibular reconstruction surgery. The aim of this study was to introduce a novel DCIA flap with a perforator-supported external oblique abdominal muscle (EOAM) island for postoperative flap monitoring. This study included five patients who underwent mandibular reconstruction using this modified technique. The DCIA flap and the EOAM island supplied by the ascending branch of the DCIA were harvested during the surgery. After mandibular reconstruction, the EOAM island was placed in the submandibular region to monitor the blood supply to the DCIA flap after surgery. The blood supply to the DCIA flap was monitored by observing the colour, texture, and bleeding condition of the EOAM island. After the monitoring period, the EOAM was removed and the ascending branch of the DCIA was ligated. The outcome was successful in all patients. The EOAM island supported by the ascending branch of the DCIA is reliable and safe, thus providing a robust option to monitor the blood supply to the DCIA flap.

Vascular iliac myofascial flap to repair compound defect of the jaw.

The vascular iliac myofascial flap is a compound flap with the deep circumflex iliac artery (DCIA) as the vascular pedicle, carrying the iliac bone and parts of the internal oblique, external oblique and muscle-fascial tissue that cover the surface of the iliac crest and inside the iliac bone. The aim of this study was to advocate a feasible surgical strategy for maxillofacial surgeons through our review of clinical applications and to improve the quality of life of patients after the operation. In recent years, Stomatology Hospital of Wuhan University has performed dozens of vascularized iliac myofascial flaps, not only to repair jaw defects but also to complete the repair of intraoral soft tissue defects. 20 patients were followed up. These patients with jaw tumors who received a vascular iliac myofascial flap to repair compound defects of the jaw from 2018 to 2020. The Quality of Life Questionnaire-Head and Neck Cancer-37 (QLQ-H&N37) was used to evaluate their speech function (Z=-0.061, P>0.05) and postoperative aesthetics (Z=-2.824, P<0.05). All patients obtained good surgical results and satisfaction in terms of aesthetics and function. The successful reconstruction of these cases prove that the vascularized iliac composite flap with myofascial tissue is a reliable flap for the reconstruction of maxillofacial defects.

Donor- and recipient-site morbidity of vascularized fibular and iliac flaps for mandibular reconstruction: A systematic review and meta-analysis.

The aim of this article is to evaluate the early and late morbidities of the donor- and recipient-site in patients undergoing mandibular reconstruction using either vascularized fibular flap (VFF) or vascularized iliac flap (VIF). Electronic databases, including PubMed, Web of Science, Cochrane Central and Embase, were explored for literature published until October 2020. A total of twenty-four articles reporting complications following mandibular reconstruction surgery with follow-up periods ranging from six to 63 months were selected based on the exclusion criteria. For each research, the JBI Critical Assessment Tool and the ROBINS-I Tool were used to analyze the methodological quality and the risk of bias. A single-arm meta-analysis was performed to have a synthesized analysis of the donor- and recipient-site early and late morbidities. Results showed that the early morbidities in VFF group ranged from 3% to 12%, and the late morbidities in VFF group ranged from 5% to 67%. In VIF group, the early morbidities ranged from 3% to 16%, and the donor-site late morbidities ranged from 6% to 43%. Complications with the top three morbidities in the VFF group were: chronic sensory disturbances at the donor-site (67%), malocclusion (22%) and chronic lower limb weakness (20%); and in the VIF group were: chronic sensory disturbances at the donor-site (43%), chronic pain at the donor-site (26%), chronic gait disturbance (20%). Further controlled clinical trials are needed to assess the long-term outcome of VFF or VIF grafting.

Comparison of donor-site engraftment after harvesting vascularized and nonvascularized iliac bone grafts.

PURPOSE: The objective of this study is to characterize the donor-site morbidity after harvesting of nonvascularized and vascularized iliac bone grafts. PATIENTS AND METHODS: Clinical data of 353 patients were collected for analysis. In addition, a questionnaire was sent to all patients asking about their perceptions of different parameters. In an individual age-matched layout, we compared 34 patients with nonvascularized iliac bone grafts with 34 patients with vascularized iliac bone grafts. RESULTS: Transplantation of vascularized bone grafts has been increasingly performed at our institution. The mean age was 41.5 years in the nonvascularized group and 48.6 years in the vascularized group. The main reason for the bony defect in the vascularized group was malignancy. The majority of postoperative functional problems were observed in obese patients. No patient had serious or long-term complications at the donor site. The amount of bone graft taken affected postoperative sensitivity disturbance and caused postoperative functional problems and pain. CONCLUSIONS: We conclude that the iliac crest is a suitable site for harvesting both vascularized and nonvascularized bone grafts measuring up to 10 x 3 cm. For larger defects that require a larger bone graft, a vascularized bone graft is more suitable with a better predictable healing capability. No significant differences in donor-site morbidity were found between the vascularized and nonvascularized bone grafts if a similar amount of bone was taken for transplant.

Maxillary reconstruction using anterolateral thigh flap and bone grafts.

BACKGROUND: Loss of the maxilla and midfacial bone buttresses after tumor resections can lead to severe functional and esthetic consequences. The loss of palate function may lead to oro-nasal communication, nasal speech, and oral intake difficulties. Several techniques have been proposed for maxillary defects reconstruction including prosthesis, locoregional flaps, or free flaps. The authors propose the use of anterolateral thigh free flap and iliac crest, or calvaria bone graft association for reconstruction of this kind of defects. METHODS: Between November 2003 and June 2007, eight patients underwent maxillectomies, with preservation of the orbital contents and simultaneous reconstruction using this technique. RESULTS: : All the flaps were harvested and transplanted successfully. No major complication occurred and only one patient developed a palatal dehiscence with partial necrosis of the skin of the flap. There were no complications at the donor sites. Speech was assessed as normal in five patients, intelligible in two patients, and poor in one patient. Six patients returned to normal diets, while two patients were restricted to soft diets. The esthetic results were evaluated by the patients themselves as good (in five cases) and acceptable (in two cases). In the remaining case, the esthetic result was deemed to be poor, due to ectropion and poor color matching of the skin used for the external coverage. CONCLUSION: The good results obtained using this technique encourage the choice of the association of anterolateral thigh and bone grafts for reconstructing maxillary complex defects.

Intraoral anastomosis of a vascularized iliac-crest flap in maxillofacial reconstruction.

Intraoral anastomosis of free flaps was introduced to avoid extraoral scars. In addition, advances in vascularized iliac-crest flap have greatly facilitated jaw reconstruction. The primary aim of this study was to evaluate feasibility and outcomes of intraoral anastomosis of vascularized iliac-crest flaps used for jaw reconstruction. Methods: From December 2015 to June 2018, 10 (3 men and 7 women) patients aged 12-55 (median, 28) years were treated at the Peking University School and Stomatology Hospital, China. Six patients underwent maxillary reconstruction, and four patients underwent mandibular reconstruction with the intraoral anastomosis of vascularized iliac-crest flaps. Conclusion: In all cases, the facial artery was easily identified by intraoral Doppler ultrasound. The operative time for the preparation of facial vessels by the intraoral approach was 30-60 minutes. All DCIA flaps were successfully harvested. All intraoral anastomoses were successfully established and survived in 9 patients. However, one flap for maxillary reconstruction was lost because of arterial spasm. Nine patients with survived flaps had unrestricted mobilization and showed facial symmetry after surgery. No healing complications were reported in the transplant region in nine patients with survived flaps, and no serious donor site complications were observed during the follow-up period.

Quality of life evaluation for patients receiving vascularized versus nonvascularized bone graft reconstruction of segmental mandibular defects.

PURPOSE: Head and neck neoplasms requiring surgical resection of the mandible can have negative consequences on patient quality of life. For patients with segmental resections, the vascularized fibular free flap and nonvascularized iliac crest are frequently used. The fibula has surpassed the iliac crest in popularity due to the success associated with a vascularized graft; however, there still remain significant advantages with the nonvascularized graft. There has not been a study comparing the quality of life associated with these two methods of mandibular reconstruction. We carried out the following study to compare quality of life of both grafts in an attempt to help guide therapeutic decisions. PATIENTS AND METHODS: Twenty-nine patients at the University of California, San Francisco undergoing mandibular resection with subsequent reconstruction with either a vascularized fibular free flap or nonvascularized iliac crest bone graft were identified. Patient quality of life was assessed with a modified version of the University of Washington Quality of Life Questionnaire, version 4. RESULTS: Eighteen patients responded (10 reconstructed previously with a fibula, 8 with iliac crest reconstructions). Patients with an iliac crest bone graft had significantly better chewing and swallowing scores (P = .04, P = .049 respectively). There was also a trend for better taste (P = .067). When patients with a history of radiation therapy were excluded, differences in chewing and swallowing were not significant (P = .26 and P = .31 respectively), whereas taste was (P = .038). CONCLUSIONS: These findings suggest that reconstruction with the iliac crest had benefits in improved function (chewing, swallowing, and taste) rather than esthetics, donor site morbidity, or psychologic discomfort as was anticipated. However, prior radiation, a relatively frequent therapy in this patient population, presents an important confounding factor. Radiation therapy is difficult to control for without limiting an already scarce patient pool, and bears with it significant morbidity that likely influenced these findings. Further study is warranted to confirm the results and further distinguish the 2 groups.

Cortical vascular canals in human mandible and other bones.

The human mandible is highly mineralized. We hypothesized that this is related to the local vascularity of the bone. This could not be examined directly, but, as a surrogate, intracortical vascular canal spaces of the human mandible were studied so that we could determine possible relationships with age, gender, location, dental status, and tissue mineralization. Canal numbers, area, and volume fraction were calculated from quantitative backscattered electron images of human mandibles aged 16-96 years. Data were compared with calvaria, maxilla, lumbar vertebra, femoral neck, and iliac crest. In the mandible, the buccal aspect of the midline was the most porous, the canals being larger and more numerous. The cortical porosity in the posterior of partially dentate mandibles was significantly greater than that of either dentate or edentate mandibles, and there was a significant increase in the size of canals in the mandible with increasing age. Female mandibles had more porous cortices. No relationship was found between cortical porosity and the degree of bone mineralization.

Medial approach for minimally-invasive harvesting of a deep circumflex iliac artery flap for reconstruction of the jaw using virtual surgical planning and CAD/CAM technology.

Donor site morbidity is the most common limitation of the deep circumflex iliac artery (DCIA) flap, so the purpose of this paper is to describe a new, minimally-invasive, approach to its harvest using virtual surgical planning and CAD/CAM technology to reduce functional and aesthetic morbidity at the donor site. Virtual surgical planning was based on preoperative computed tomographic data. A newly-designed surgical guide made using CAD/CAM technology was used to transfer the virtual surgical plan to the site of operation. This enabled us to raise a bicortical flap from the pelvis with preservation of the anterior superior iliac crest from the medial side with minimal muscular stripping. The guide, designed at slightly less than 90° to the lateral cortex, allowed the cut segment of bone to be raised medially. The new virtual surgical planning guide allowed a medial approach with reduced stripping of muscle and lower morbidity. No complications were encountered during the operation or the healing phase. Patients treated in this way had a shorter recovery period, with minimal complaints about walking or loss of profile of the hip. We conclude that virtual surgical planning can aid a minimally-invasive approach with predictable results. This allows a medial approach to the harvest of DCIA with preservation of important anatomical structures, and a reduction in donor site morbidity.

In vivo tissue engineered bone versus autologous bone: stability and structure.

This pilot study investigated the biomechanical properties of prefabricated, vascularized bioartificial bone grafts, which may provide an alternative bone source for the restoration of segmental osseous defects. Vascularized bioartificial bone grafts comprise an artificial customized scaffold made of beta-tricalcium phosphate. Bone formation along the prefabricated scaffold is induced by autogenous cancellous bone. Vascularization of the bone graft is provided by the host's vascular system. Within 6 months, a mammalian bioreactor (sheep were used in the present study) creates heterotopic vascularized bioartificial bone grafts of a predetermined anatomical shape, which can be harvested for reconstructing osseous defects. The bioartificial bone grafts in this study contained up to 25% bone tissue, as shown by histomorphometric analysis and computed tomography. Moreover, unconfined compression tests revealed that the constructs had mechanical characteristics similar to those of ovine cancellous bone. Therefore, this method could be applied to generate vascularized prefabricated bone substitutes for critical-size defects.

Evaluation of vascularized graft reconstruction of the mandible with Tc-99m MDP bone scintigraphy.

AIM: The aim of this study was to evaluate the value of bone scintigraphy for the assessment of graft viability following vascularized bone grafts in patients with mandibular reconstruction. METHODS: We investigated 16 patients with vascularized grafts from the fibula (13 patients) and iliac crest (3 patients) in the last 8 years. For the follow up of all these patients, Tc-99m MDP bone scintigraphy was performed between 2-10 days postoperatively. SPECT study was included in 5 patients. For the evaluation of the grafts, a six-grade scoring system was used. The grading system was based on a comparison of tracer uptake between graft and the cranium. The uptake was defined as increasing from grade 6 to grade 1. RESULTS: Thirteen of the 16 grafts had an uncomplicated clinical course. Complications in the graft occurred in three patients. In the analysis of planar scintigrams, patients with uncomplicated healing showed increased uptake in 12 of the 13 grafts (grade 1-3) and 1 showed the same level tracer uptake compared to cranium (grade 4). In the failed 3 grafts, decreased uptake was observed (grade 5 and 6). In 5 patients, SPECT was performed in addition to planar imaging. In these patients, 4 of the 5 grafts had an uncomplicated clinical course and 1 had a complicated one. In the analysis of SPECT images, while all the grafts with an uncomplicated clinical course exhibited increased uptake (grade 1-3), the failed graft showed decreased uptake (grade 6). CONCLUSION: Three-phase bone scintigraphy performed within 10 days after the mandibular reconstruction is a useful tool to monitor the viability and early complications of vascularized mandibular bone grafts. SPECT is also recommended. It may contribute to interpretation of the bone scans and to precise assessment of graft viability.

The Evolution of Free Vascularized Bone Transfer: A 40-Year Experience.

BACKGROUND: The first successful free vascularized bone flap was performed on June 1, 1974 (and reported in 1975), using the fibula. This was followed by the iliac crest based on the superficial circumflex iliac artery in 1975 and then the deep circumflex iliac artery in 1978. METHODS: A total of 384 transfers using fibula (n = 198), iliac crest (n = 180), radius (n = 4), rib (n = 1), and metatarsal (n = 1) were used between June of 1974 and June of 2014 for reconstruction of the mandible (n = 267), maxilla (n = 20), clavicle (n = 1), humerus (n = 8), radius and ulna (n = 21), carpus (n = 3), pelvis (n = 2), femur (n = 11), tibia (n = 47), and foot bones (n = 4). Indications were tumor ablation (n = 286), trauma (n = 84), osteomyelitis (n = 2), and the congenital deformities hemifacial microsomia (n = 2) and pseudarthrosis of the tibia (n = 9) and ulna (n = 1). RESULTS: Successful transfer was achieved in 95 percent of patients. Union varied with the recipient bone, from 6 to 8 weeks in the jaw, 2 to 3 months in the upper limb, and 3 to 4 months in the femur and tibia. Union was fastest with iliac crest. The fibula provided easier dissection; it could be raised on either peroneal or anterior tibial vessels; the skin flap could be designed distally; it could be placed centrally in the medullary cavity of long bones; and hairline stress fracture in the lower limb frequently preceded rapid subperiosteal hypertrophy. The fibula lacks sufficient height for osseointegration, whereas iliac crest is ideal. Osteotomies of either bone are possible to straighten or increase curvature. CONCLUSIONS: The fibula is best for long bone or angle-to-angle jaw reconstruction, especially in edentulous patients. Iliac crest is best for hemimandible, curved bones (pelvis, carpus, and metacarpus), and as an alternative for short, straight, 6- to 8-cm-long bone defects.

ONE-STAGE (PRIMARY) RECONSTRUCTIONS OF RESECTION MANDIBULAR DEFECTS BY MEANS OF AUTOGENE VASCULARISED ILIAC AND FIBULAR TRANSPLANT.

UNLABELLED: Mandibular resections are most often performed in cases of tumour ablations. Contemporary oral and maxillofacial surgery acknowledges primary one-stage reconstructions of defects through microvscularised transplants. They have intact circulation due to the primarily performed vascular anastomoses. For recovery of the shape and the function of the mandible most frequently used transplants are derived from the iliac crest and fibula. Goal and objectives. We share our experience in the one-stage recovery of mandibular defects simultaneously with the resection, by means of autogene vascularised iliac and fibular transplants. Material and method. 8 patients aged from 24 to 61 (female - 1, male - 7) with tumours engaging the mandible (5 - benign and 2 - malignant) were treated surgically and followed up. We carried those out using extraoral approach in 7 cases, and intraoral aproach - in 1. The resulting post resection mandibular defects in 3 of the patients were reconstructed by means of one-stage autogene bone vascularised iliac transplants. In 5 patients the defects were recovered primarily through vascularised fibular autotransplants. The surgical techniques and protocols, to assess the outcome and characterize of the methods are presented. RESULTS: We tracked down the postoperative results of the mandibular reconstructions for a period of 1 to 3 years. Support for the lips and tongue was achieved providing for satisfactory speech and feeding. Anatomical remodeling was observed. The conditions for the production of dental implants were improved. In the case, when we used intraoral approach the facial aesthetics was fully restored, as for the rest it was satisfactory. CONCLUSIONS: Vascularised autogene iliac and fibular bone transplants are extremely appropriate for reconstructions of significant and complicated mandibular and other defects in the maxillofacial area. Their survival is independent from the recipient area, and secured through the vessel anastomoses. With sound surgical technique, success rate of the method is to a large extent guaranteed.

Single-stage reconstruction of mandibular and soft tissue defects using a free osteocutaneous groin flap.

Microvascular reconstruction of the mandible and soft tissues using the composite groin flap is ideal in selected patients. No other available bone so closely approximates the mandible in both thickness and curvature as does the iliac crest. The soft tissues are available for reconstruction and may allow the surgeon to avoid a second flap, except in cases where both lining and cover are needed. The deep circumflex artery is of generous size, usually 2 to 2.5 mm in diameter, allowing greater reliability in the microvascular anastomoses. The flap has a fairly long vascular predicle, 6 to 8 cm. The ability of this flap to withstand irradiation and infection because of its blood supply permits early institution of postoperative radiotherapy and prevents bone loss due to small intraoral wound dehisicence or total flap loss. Although the donor site requires extensive dissection, it can be closed primarily, eliminating the need for skin grafts or other flaps. As further experience is gained with this flap, both the functional and cosmetic results should be improved. In patients undergoing resection of the remaining portion of the mandible, the symphysis or the anterior portion of the mandible, a procedure of this type should be done primarily to prevent deformity and to minimize disability for the patient.

Stability of dental implants in microvascular osseous transplants.

Microvascular iliac crest and scapula transplants have been used in reconstruction of the lower jaw following tumor surgery. It has only been with the insertion of dental implants that a satisfactory prosthetic rehabilitation of the patient has been achieved. For this study, a follow-up of 38 patients with lower jaw tumors was carried out. The patients had been treated with partial resection of the lower jaw and neck dissection with microvascular iliac crest transplants (n = 20) or microvascular scapula transplants (n = 18); this was followed with dental implants (n = 143) in the region of the transplants or the local lower jaw. One hundred thirty-nine of the 143 dental implants were loaded by prosthetic superstructures. In all patients, the implant situation was evaluated on average 2 years 5 months after implantation. Periotest values, periimplant probing depths, and contact bleeding were registered, and the extent of periimplant bone loss was defined radiographically. The clinical situation in the region of the implant was compared for both types of implants and also with the nonresected lower jaw. The average Periotest values were within the normal range for all groups. In one scapula implant, however, a better average of Periotesting, -3.3, was found compared with implants of the iliac crest with Periotest values of -0.7. A measurement of -2.1 was found for the local lower jaw, similar to that of scapula implants. Pathologic probing depths were found for all three compared groups. The radiographically determined vertical loss of bone was the same for all three groups, on average 1 mm at 27 months postoperatively. The highest incidence of sulcus bleeding was found in the scapula implant group. Thus, it can be stated that the scapula transplants provide a similar transplant site to local lower jaw bone, whereas implants in iliac crest transplants show lesser bony stability. Periimplant soft-tissue conditions are worse for both types of transplants compared with local tissue of the lower jaw.

Postoperative function after implant insertion in vascularized bone grafts in maxilla and mandible.

Between 1988 and 1992, 80 Brånemark-type implants were inserted in 18 patients during reconstruction of the mandible or maxilla with vascularized iliac crest or scapula grafts with or without additional soft tissue pedicles. In these procedures, nine vascularized bone grafts were combined with a primary insertion of 32 implants and a secondary insertion of 48 implants. Twelve patients are currently wearing the implant-borne dentures. From 32 implants inserted primarily, eight could not be used for prosthodontic rehabilitation because three were lost with a graft, three were left as sleepers, and two demonstrated a lack of osseointegration. None of the implants inserted secondarily in grafts were lost. Primary implant insertion should be performed only in close cooperation with the prosthodontist and in selected cases, for example, in free-end reconstruction of the mandible with a straight graft and where a limited number of implants is needed. Although restoration of masticatory function in patients with head and neck cancer can be achieved, compared with a healthy control group, functional impairments remain. Patients subjectively favor the nonreconstructed side of the mandible or maxilla for chewing. These findings can be correlated with a postoperative follow-up investigation using a miniature force transducer and the T-scan system.