Vascularized bone flaps in oromandibular reconstruction. A comparative anatomic study of bone stock from various donor sites to assess suitability for enosseous dental implants

[Vascularized bone grafts in the treatment of hemifacial microsomia]

A systematic and theoretic review is performed on the vascularised bone donor sites that may be useful in the case of hemifacial microsomia. A review of the literature reveals that the iliac crest and the scapula are the most commonly used vascularised bone grafts. A case study is included in the paper, showing an hemifacial microsomia reconstruction using a composite fibular vascularised bone graft. They highlight the criterias they think fundamental for choosing the vascularised bone graft donor site regarding the aims of the reconstruction of a Pruzansky grade II or III.

Treatment of a microvascular reconstructed mandible using an implant-supported fixed partial denture: case report

Oral rehabilitation of patients with mandibular discontinuity defects is a problem that faces both the oral surgeon and the restorative dentist. Advances in microvascular surgery can provide the mandible with vital bone grafts. Often, reconstruction of the bony defect alone does not guarantee an adequate foundation for successful conventional prosthetic rehabilitation. Osseointegrated implants placed in the microvascularized grafted bone offer an opportunity for improved function and patient satisfaction. This case report describes the use of an implant-supported bridge in a vascularized fibular bone graft to reconstruct a traumatic partially resected mandible.

Comparative radiologic study of bone density and cortical thickness of donor bone used in mandibular reconstruction

OBJECTIVE

The aim of this study was to compare the total cancellous bone density, bone-implant interface density, and cortical thickness of 6 donor bone types commonly used in oral and maxillofacial reconstruction.

METHODS

A total of 120 bones from 20 Korean adults-including iliac bones, fibulas, cranial bones, scapulas, ribs, and clavicles-were selected. The implant recipient site was determined by the shape, contour, and anatomical limitations of the bones. The serial cross-sectional images of each bone were then acquired through computed tomography. Total cancellous bone density, bone-implant interface density around the imaginary implant fixture, and the cortical thickness along both sides of the imaginary fixture on each cross-sectional image were evaluated and compared.

RESULTS

The cancellous bone density of each donor bone type had a statistically significant difference. The cranial bone showed the highest cancellous bone density, followed by the iliac bone, clavicle, scapula, rib, and fibula (P <.05). The bone-implant interface density of the cranial bone, clavicle, fibula, and scapula each belonged to the same Duncan's group, whereas the rib and iliac bone showed lower bone-implant interface density. In average cortical thickness, the scapula and fibula had a thicker cortex surrounding the imaginary implant than the other bones, and the rib had the thinnest cortex.

CONCLUSION

Although more extensive testing is needed to explain the clinical implications of these results, the findings of this study may help clinicians choose the most appropriate donor bone.

The optimum method for reconstruction of complex lateral oromandibular-cutaneous defects

BACKGROUND

Ablation of large intraoral cancers can create extensive through-and-through defects of the lateral face, resulting in loss of external facial skin, the lateral and anterior mandible, and the lateral mouth. Repair requires reconstruction of the lips, mandible, and full-thickness cheek defects. Ideal reconstruction with vascularized composite free flaps requires adequate bone and sufficiently large, yet versatile, skin flaps capable of resurfacing extensive intraoral and external defects.

METHODS

A series of 12 patients with large lateral facial-mandibular defects is reviewed. All patients were treated for squamous cell carcinoma except for 1 patient with osteoblastic sarcoma of the mandible. All patients underwent primary reconstruction with various free flap techniques, including 6 scapular free flaps, 2 iliac crest free flaps, 3 free fibula flaps, and 1 radial forearm flap. Attainment of reconstructive goals, free flap survival, and complication rates were assessed.

RESULTS

All defects were successfully reconstructed in the primary setting. No flap failures occurred. One venous occlusion was successfully salvaged. No orocutaneous fistulas or postoperative hematomas were noted.

CONCLUSION

The reconstructive options for extensive defects of the lateral face and jaw are reviewed with attention to the complex three-dimensional soft tissue requirements. The superiority of the scapular composite flap is emphasized because this single free flap provides two independent and versatile skin paddles of optimal thickness in addition to adequate bone stock.

Torsional strength of the radius after osteofasciocutaneous free flap harvest with and without primary bone plating

The osteocutaneous radial forearm free flap (OCRFFF) has not gained widespread popularity in mandibular reconstruction, primarily because of concerns about pathologic fracture of the weakened radius. This study examines the effectiveness of plate fixation of the radius bone after harvest of the OCRFFF as a mechanism to minimize donor-site morbidity and increase the usefulness of the OCRFFF. Matched pairs of fresh human cadaveric radius bones were used in this study. Two study groups were designed. The first group was used to define the amount of strength lost after a typical bone graft harvest. The second group was designed to demonstrate how much torsional strength was regained by the application of an orthopedic reconstruction plate. Statistically significant results were obtained for both groups. In group 1, the strength of the cut bones compared with that of the unaltered bones was significantly decreased by 82% (P = 0.016). In group 2, the cut bones reinforced with a plate were 75% stronger (P = 0.002) than the bones that were only cut. Although the radius bone is significantly weakened by the harvest of a graft, much of this strength can be regained with plate fixation of the radius.

Comparisons of bone volumes and densities relating to osseointegrated implants in microvascularly reconstructed mandibles: a study of cadaveric radius and fibula bones

The study was designed to compare the dimensions and densities of two frequently used bone donor sites with regard to placement of endosseous dental implants in microvascularly reconstructed mandibles. A total of 40 radii and of 40 fibulae were investigated. Fifty two percent of the fibulae had adequate bone volume for the positioning of four 10 mm implants, while this figure was 55% for the radii. After using the 'double barrel' technique the placement of four 10 mm implants succeeded in 87% of all the fibulae. Due to the lack of bone length required, this special technique was not possible in the radii investigated. Cortical thickness and density of bone were higher in the radii when compared with the fibulae. In each bone the central and distal parts presented the highest values of cortical thickness and density. Although the radius offers enough substantial bone for implant placement in some cases this cannot be used for clinical purpose, as only hemicortical grafts can be obtained. Otherwise the resulting donor site morbidity would be intolerable. In conclusion, our results support the clinical experience that the fibula is today's 'work horse' donor site for reconstruction of the mandible.

Evaluation of a free vascularized medial tibial bone graft in dogs

OBJECTIVE

To develop a free vascularized tibial bone graft based on the periosteal saphenous blood supply.

STUDY DESIGN

Preliminary anatomic study of medial tibial blood supply. In vivo comparison of a vascularized and avascular tibial bone graft.

ANIMALS

Nine canine cadavers; 14 healthy adult dogs that weighed 25 to 32 kg.

METHODS

An anatomic study of the vascular supply of the medial aspect of the tibia was performed using the Spalteholz technique. A bone graft consisting of the medial aspect of the tibia was transferred to a mandibular defect as a vascularized graft in 7 dogs and as an avascular graft in 7 dogs. Bone scans were performed to evaluate graft perfusion. Radiographic evaluation of the mandibles and tibias was performed. The dogs were killed after 60 days, five mandibles from each group were examined histologically, and two from each group were evaluated using the Spalteholz technique.

RESULTS

The saphenous vascular pedicle provides vascular perfusion to the medial tibial cortex. Bone scans and radiographic evaluations were consistent with viable bone in the vascularized grafts, and nonviable bone in the avascular grafts. Histological examination revealed live, healing bone in vascular grafts and necrotic bone in avascular grafts. Spalteholz evaluation revealed many small arborizing vessels in the vascular grafts and no organized vasculature in the avascular grafts.

CONCLUSIONS

The vascularized medial tibial cortical bone graft survived and proceeded to bony union in the mandibular body defect more readily than the avascular graft in this experimental model.

CLINICAL RELEVANCE

A vascularized medial tibial bone graft is a suitable free graft for use in reconstructing bone defects in dogs.

Mandibular reconstruction following ablative tumour surgery: an overview of treatment planning

BACKGROUND

In the last half century the evolution of mandibular reconstruction has resulted in a multitude of surgical procedures that have been brought about by advances made in bone science, grafting techniques and materials technology. With the ever increasing number of surgical options currently available it has become essential to take stock of these achievements and reconsider the fundamental principles of reconstructive surgery.

METHODS

The choice of reconstructive techniques is only part of a wider number of variables that must be considered which will ultimately determine the success or failure of the procedure.

RESULTS

Variables likely to influence the outcome of mandibular reconstruction are the site and extent of the defect, the needs and tolerance of the patient, the timing of reconstruction and the surgical skill and techniques available.

CONCLUSION

By careful consideration of these cardinal variables it may be possible to formulate a treatment plan that will not only satisfy the essential needs of the patient but also help increase the likelihood of a successful outcome.

Microvascular reanastomozed allogenous iliac crest transplants for the reconstruction of bony defects of the mandible in miniature pigs

The effects of immunosuppression with cyclosporin A and prednisolone regimens for allogenous iliac crest bone grafts used for mandibular reconstruction were investigated in 40 miniature pigs, for periods of 2, 4 and 16 weeks. Autogenous and allogenous bone grafts without immunosuppression served as controls. Specimens were evaluated by routine histology, direct magnified radiography and fluorescence microradiography. Four out of five autogenous transplants showed a preserved vascular architecture and bony union. None of the allogenous transplants without immunosuppression survived. Primary bone healing of the allografts was noted after short-term immunosuppression. However, occlusion of the nutrient vessels was noted ten days postoperatively. The allografts were not rejected after cessation of the immunosuppressive therapy within an observation period of 4-12 weeks. Revascularization of all areas of the allografts and creeping substitution of the transplanted bone were noted after seven weeks. Infection of the allografts, with failure of bony union, was noted in nine animals, but primary healing of allografts with short-term immunosuppression was demonstrated.

Donor site evaluation for fibula free flap transfer

PURPOSE

The role of routine preoperative angiography in patients undergoing fibula flap transfer remains controversial. A recent survey of experienced microvascular surgeons indicated that routine angiography may be unnecessary in patients with no symptoms of peripheral vascular disease and normal lower extremity pulses. To study the necessity of performing preoperative vascular imaging studies, the incidence of congenital and acquired vascular anomalies that prevented the harvest of a fibula flap is reported in a series of patients undergoing evaluation for oromandibular reconstruction

PATIENTS AND METHODS

A series of 19 consecutive patients who underwent preoperative lower extremity vascular imaging studies in anticipation of performing a fibula free flap is presented.

RESULTS

Angiographic findings significantly altered the surgical reconstruction that was performed in 4 of 19 (21%) patients. Three patients with a history or examination suggestive of peripheral vascular disease were excluded on the basis of the findings at the time of radiographic study. In a fourth patient, the contralateral leg was used for reconstruction when preoperative angiography showed a dominant peroneal artery supplying the foot in the extremity initially considered for flap harvest.

CONCLUSION

History and physical examination are not helpful in detecting most congenital vascular anomalies that would place the foot at risk for ischemia if the peroneal artery is sacrificed. The findings of this small series are consistent with the previously documented incidence of anomalous blood supply to the foot and demonstrate the need for preoperative vascular imaging studies in patients undergoing fibula free flap transfer to avoid a potentially catastrophic complication.

Functional dental rehabilitation of massive palatomaxillary defects: cases requiring free tissue transfer and osseointegrated implants

BACKGROUND

Mandibular reconstruction with functional dental rehabilitation using a free tissue transfer bone flap as the substrate for osseointegrated implant-borne or implant-retained dental prostheses is well described. Similar use of these techniques in maxillary dental rehabilitation is less frequent and has received less attention in the literature. However, in selected cases of extensive composite defects of the maxilla, free tissue transfer reconstruction of the maxillary arch and the use of implant-borne or implant-retained dental prostheses is the only satisfactory method of achieving functional dental rehabilitation.

METHODS

Three cases of maxillary reconstruction and dental rehabilitation using free tissue transfer with implant-borne or implant-retained prostheses are presented. Patient selection, reconstructive technique, and the biomechanical considerations in maxillary dental rehabilitation of large palatomaxillary defects are presented.

RESULTS

The patients in this report were restored to full maxillary dental functioning. One implant of 17 implants placed in free flap bone was lost due to failure of osseointegration; 94% of the implants placed are stable an average of 18 months after dental rehabilitation was complete.

CONCLUSIONS

In selected patients with extensive palatomaxillary defects due to ablative surgery or trauma, the use of free tissue transfer and osseointegrated implant-borne or implant-retained dentures may be the only method possible to restore maxillary dental function. Dental rehabilitation of large maxillary defects presents a number of biomechanical challenges which must be clearly understood and overcome to achieve a long-term, functional dental rehabilitation.

Osseointegrated implants in the head and neck cancer patient

BACKGROUND

Osseointegrated implants allow patients with oromandibular defects to obtain complete or partial dentition via implant-assisted or implant-borne prostheses. Implants restore masticatory and occlusal function, improving oral intake and articulation. However, use of implants in head and neck cancer patients has been discouraged due to lack of data supporting their utility in these patients. This study attempts to establish the validity of using osseointegrated implants for dental restoration in head and neck cancer patients.

METHODS

Six patients who underwent resection/reconstruction for head and neck cancer received osseointegrated implants. Integration was assessed clinically, radiographically, and mechanically at 4-8 months; oral intake, mastication, and articulation were evaluated 6-12 months after receiving the dental prosthesis.

RESULTS

Osseointegration occurred in 92% (24/26) of the implants: 100% (14/14) in neomandibles and 83% (10/12) in native mandibles. One patient had implants (2/5) that failed to integrate. The remaining patients' implants were immobile, free of infection, with no osteoradionecrosis. These patients tolerated a regular diet and experienced weight gain and improved articulation.

CONCLUSIONS

The advent of osseointegrated implants and their compatibility with native and neomandible allows the restoration of functional dentition in patients undergoing ablative surgery for head and neck cancer.

Reconstruction of massive defects in the head and neck: the role of simultaneous distant and regional flaps

BACKGROUND

Massive defects resulting from excision of advanced head and neck tumors may not be amenable to reconstruction using a single technique of tissue transfer. Sixteen patients undergoing reconstruction using simultaneous free flaps and pedicled regional flaps are presented.

METHODS

Regional flaps included the pectoralis major, deltopectoral, cervical visor, paramedian forehead, cervicofacial, and nape of neck flaps. Microvascular tissue transfers included the radial forearm, iliac crest, parascapular/latissimus dorsi, rectus abdominis, fibula, and lateral thigh free flaps.

RESULTS

Most defects involved both aerodigestive mucosa and external cutaneous skin. Mucosal reconstruction was carried out using the soft-tissue component of the free flaps, whereas vascularized bone was used for mandibular reconstruction. Regional flaps were used to reconstruct skin of the face and neck.

CONCLUSIONS

When planned and applied in a stepwise fashion, simultaneous free flaps and regional flaps are complimentary for the reconstruction of complex wounds in the head and neck.

Aesthetic and functional reconstruction with the trapezius osseomyocutaneous flap and dental implants in oral cavity cancer patients

The trapezius osseomyocutaneous flap is the only pedicled flap that is able to transfer vascularized bone for mandibular reconstruction as well as skin for intra-extra oral reconstruction. The trapezius muscle also helps to fill the defect created by the neck dissection and covers the vessels of the neck. This flap has been used in our maxillofacial surgery service during the past 14 years. In spite of having incorporated microvascular flaps in our reconstructive techniques it continues to be one of the flaps we use in selected patients for bone and soft tissue compound defects of the oral cavity. We describe in this article our experience using this flap with dental implants in order to achieve a functional reconstruction. We also discuss when we use this flap for mandibular reconstruction and when a free vascularized flap is used.

Endosteal implants in the irradiated lower jaw

Since 1990 Endosteal implants have been inserted in the irradiated lower jaw at our clinic. IMZ implants have been used for dental rehabilitation in 26 patients (21 male, 5 female) suffering from squamous cell carcinomas stage T2-T4 136. The implants were either placed in local bone and soft tissue (group 1, n = 60 implants), or in local bone after marginal mandibulectomy and transplanted soft tissue (group 2, n = 26 implants), or in transplanted bone and soft tissue (group 3, n = 52 implants). Life-table analysis according to Kaplan-Meier demonstrated a 3-year implant survival rate of 87.8% in Group 1, 69.1% in Group 2 and 58.3% in Group 3. There was no statistical significant difference in the amount of marginal bone loss and the degree of marginal infection between the three groups (P > 0.29). Major complications: A mandibular fracture passing through an empty implant socket 8 months after implant loss (Group 2) was caused by postradiation-osteonecrosis; implant removal and bone resection was mandatory. The poor results of the bone graft group may be explained by two patients, in whom simultaneous placement of implants in nonvascularized bone grafts was carried out, intraoral tissue breakdown led to graft failure and loss of the implants (n = 10).

Long-term evaluation of patients undergoing immediate mandibular reconstruction

BACKGROUND

Immediate reconstruction following segmental mandibulectomy is an accepted surgical technique. The benefits and patient selection criteria need to be established.

PATIENTS AND METHODS

Forty-seven patients who underwent immediate reconstruction of the mandible were followed for up to 14 years. Survival, complication rates, and functional results were analyzed.

RESULTS

Median survival was 39 months and actuarial 5-year survival was 40%. Two patients died in the postoperative period, and 9 suffered major reconstruction-related complications. The majority of these complications were related to the use of reconstruction plates, and occurred when the mandibular defect included the arch or when the plates were covered by pectoralis flaps. Half of the patients interviewed were able to eat a regular diet.

CONCLUSIONS

Mandibular reconstruction can be performed safely and expeditiously in nearly all patients undergoing segmental mandibulectomy. Functional results and long-term survival will be acceptable in many cases.