"Mandibular and facial reconstruction" rehabilitation of the head and neck cancer patient.

Cancer surgery and its reconstruction today can result in functional and cosmetically supportive results for most patients. Today's better understanding of malignant tumor kinetics has evolved preservative and precision extirpative surgery which has on one hand enhanced cure rates and on the other hand has preserved function and appearance in such patients. Today's reconstructive techniques have a sound basis in wound healing and bone regeneration science so as to be predictable and long lasting. We now consistently reconstruct cancer patients with minimal complications and without adding undue deformity and disability. Within just the past ten years the additional advancement of osseointegrated implants has taken functional results related to chewing force and efficiency to a higher level. These implants provide for an optimal return of eating ability to closely match those with natural dentitions. Such implants have also been taken a step further with their application to facial unit restorations. Today facial units with the excellent tissue color and consistency matches made possible by available elastic materials are worn with confidence and comfort by those who require them. The messy and ineffectual adhesives of the past have been discarded. At the time of this writing the hope for the immediate future is the availability of recombinant human BMP. As the next anticipated advance in complete cancer reconstruction it has the potential to regenerate physiologically normal bone without bone grafting. The reduction in morbidity and operating room time would be an enormous step forward, as would the applicability of reconstruction to more people at a reduced cost.

Relationship of oxygen dose to angiogenesis induction in irradiated tissue.

This study was accomplished in an irradiated rabbit model to assess the angiogenic properties of normobaric oxygen and hyperbaric oxygen as compared with air-breathing controls. Results indicated that normobaric oxygen had no angiogenic properties above normal revascularization of irradiated tissue than did air-breathing controls (p = 0.89). Hyperbaric oxygen demonstrated an eight- to ninefold increased vascular density over both normobaric oxygen and air-breathing controls (p = 0.001). Irradiated tissue develops a hypovascular-hypocellular-hypoxic tissue that does not revascularize spontaneously. Results failed to demonstrate an angiogenic effect of normobaric oxygen. It is suggested that oxygen in this sense is a drug requiring hyperbaric pressures to generate therapeutic effects on chronically hypovascular irradiated tissue.

Simulated nasoalveolar palatal defects: a canine model to study bone grafts.

A simple, surgical technique to create a simulated nasoalveolar palatal defect in the canine is described. The procedure has been performed in 60 canines, and we have not experienced closure of the created clefts. The surgically created clefts had to fulfill five criteria: (1) bilateral maxillary alveolar clefts had to exist in each research animal; (2) each cleft had to have a 1-cm bony width; (3) a demonstrable oronasal communication had to be present; (4) each cleft had to be lined by healthy epithelialized mucosa; (5) there had to be functional teeth adjacent to each side of every cleft.

Clinical application of bone biology to mandibular and maxillary reconstruction.

Bony reconstruction of the mandible and maxilla is accomplished through the application of three general approaches: cancellous marrow grafts, cranial bone grafts, and microvascular transfers. This article discusses each of these techniques in detail.

The potential for HIV transmission through allogeneic bone. A review of risks and safety.

Over the past two decades, oral and maxillofacial surgeons have gained a greater appreciation for the biology of allogeneic bone healing, resulting in a dramatic increase in its indications and use. Unfortunately, this time period has also ushered in near epidemic proportions of HIV-infected persons, some of whom might be considered as potential donors of allogeneic bone. As this article will discuss, surgeons and tissue bank teams alike must be aware of the clinical and serologic criteria associated with an acceptable donor. Only in this way can contamination-free specimens be obtained and surgically implanted.

Platelet-rich plasma: Growth factor enhancement for bone grafts.

Platelet-rich plasma is an autologous source of platelet-derived growth factor and transforming growth factor beta that is obtained by sequestering and concentrating platelets by gradient density centrifugation. This technique produced a concentration of human platelets of 338% and identified platelet-derived growth factor and transforming growth factor beta within them. Monoclonal antibody assessment of cancellous cellular marrow grafts demonstrated cells that were capable of responding to the growth factors by bearing cell membrane receptors. The additional amounts of these growth factors obtained by adding platelet-rich plasma to grafts evidenced a radiographic maturation rate 1.62 to 2.16 times that of grafts without platelet-rich plasma. As assessed by histomorphometry, there was also a greater bone density in grafts in which platelet-rich plasma was added (74.0% +/- 11%) than in grafts in which platelet-rich plasma was not added (55.1% +/- 8%; p = 0.005).

Prevention of osteoradionecrosis: a randomized prospective clinical trial of hyperbaric oxygen versus penicillin.

A prospective randomized trial comparing hyperbaric oxygen and systemic antibiotics in the prevention of osteoradionecrosis was presented. The results indicated, in a high-risk population who required tooth removal in irradiated mandibles, that up-front hyperbaric oxygen produced an incidence of osteoradionecrosis of 5.4% as compared with the antibiotic group of 29.9% (P = .005). Hyperbaric oxygen should be considered a prophylactic measure when post-irradiation dental care involving trauma to tissue is necessary.

The use of implants in the reconstruction of oral cancer patients.

The spectrum of osseointegrated implant applications in cancer patients is quite varied today. In the future, it will be even wider and more varied, limited only by the ingenuity of practitioners, skills of reconstructive surgeons, biology of the reconstruction, and cost restraint efforts. Today's practitioners are challenged to preserve and enhance the benefits of osseointegrated implants in some of the patients who need them most, the cancer patient. It is done by improving one's own skills by research and by education.

A feasibility study evaluating rhBMP-2/absorbable collagen sponge for maxillary sinus floor augmentation.

This 16-week open-label study assessed the safety and technical feasibility of implanting human recombinant bone morphogenetic protein-2 delivered on an absorbable collagen sponge (rhBMP-2/ACS) for two-stage maxillary floor sinus augmentation. This first use of rhBMP-2/ACS in human clinical maxillary sinus floor augmentation included 12 patients with inadequate bone height in the posterior maxilla. The total delivered dose of rhBMP-2 implanted varied from 1.77 to 3.40 mg per patient. The rhBMP-2/ACS device was easily handled. Significant bone growth was documented by computerized tomographic scans in all evaluable patients (11/12). The overall mean height response for the maxillary sinus floor augmentation was 8.51 mm (95% confidence interval 6.07 to 10.95). There were no serious or unexpected immunologic or adverse effects and no clinically significant changes in complete blood counts, blood chemistries, or urinalysis results. The most frequent adverse effects were facial edema, oral erythema, pain, and rhinitis. Eleven patients have received dental implants and follow-up examinations are still being conducted. Histologic examinations of core bone biopsies obtained at the time of dental implant placement confirmed the quality of the bone induced by rhBMP-2/ACS. These results tend to indicate that rhBMP-2/ACS may provide an acceptable alternative to traditional bone grafts and bone substitutes for maxillary sinus floor augmentation procedures in humans.

Suppurative osteomyelitis, bisphosphonate induced osteonecrosis, osteoradionecrosis: a blinded histopathologic comparison and its implications for the mechanism of each disease.

Statistically, significant numbers of central bone specimens of suppurative osteomyelitis of the jaws (SOJ), bisphosphonate induced osteonecrosis of the jaws (BIONJ), and osteoradionecrosis of the jaws (ORNJ) were compared. All three evidenced the common finding of necrotic bone with empty osteocytic lacunae, Haversian and Volkmann canals, but each showed a distinctive histopathologic pattern indicating a different disease mechanism and treatment options. Suppurative osteomyelitis was characterized by intense marrow inflammation and marrow vessel thrombosis with retention of viable osteoclasts and periosteum. Bisphosphonate induced osteonecrosis was characterized by an empty marrow space with empty Howship's lacunae and an absence of osteoclasts but viable periosteum. Osteoradionecrosis was characterized by a collagenous hypocellular, hypovascular marrow space and nonviable periosteum. Histologic evidence in SOJ indicates a microorganism provoked intense inflammation and marrow vascular thrombosis creating an environment conducive to continual bacterial proliferation. BIONJ is seen as a non-inflammatory drug toxicity to bone by osteoclastic death leading to over suppression of bone renewal, and ORN as another non-inflammatory condition caused by a high linear energy transfer that impairs or kills numerous cell types in the field of radiation including periosteum, bone, and all soft tissue.

Current advances in reconstruction of the mandible in head and neck cancer surgery.

Today's reconstruction of head and neck cancer related deformities is based on an in-depth knowledge of soft and hard tissue repair coupled with the technical ability to transplant and reorient soft and hard tissues into a functional and cosmetic improvement for each patient. The recent advances of (1) the science of bone regeneration, (2) myocutaneous flaps, (3) hyperbaric oxygen, and (4) allogeneic bone cribs have resulted in reconstructions which are now predictable outcomes with few complications and minimal morbidity. This writing will discuss the contribution and mechanism of each of these four advances and how their application can be used to consistently reconstruct even large deformities with both hard and soft tissue loss, as well as in tissues which have been severely radiated.

Osteoradionecrosis: a new concept of its pathophysiology.

The classic sequence in the pathogenesis of osteoradionecrosis of the jaws has been accepted as radiation, trauma, and infection. This paper challenges this sequence and offers a new one more accurately describing the biochemical and cellular pathology. The clinical data are based on 26 consecutive cases of osteoradionecrosis from which 12 en bloc resection specimens were cultured and stained for microorganisms. Review of the histories and treatments, as well as the microbial assays, indicates that microorganisms play only a contaminant role in osteoradionecrosis and that trauma is only one mechanism of tissue breakdown leading to the condition. The sequence suggested by this study is as follows: (1) radiation, (2) hypoxic-hypocellular-hypovascular tissue, (3) tissue breakdown, and (4) chronic non-healing wound.

An improved technique for development of the pectoralis major myocutaneous flap.

The pectoralis major myocutaneous flap is the most commonly employed muscle skin transfer used in soft-tissue reconstruction of defects of the upper neck and jaw region. This article presents conceptual and technical changes in the development of the pectoralis major myocutaneous flap that preserve a greater vascular pedicle and enhance the flap's arc of rotation. Data from 54 consecutive cases using this modified approach show a reduction in complications, a greater range of use, and consistent healing in radiated and nonradiated tissues without requiring sectioning or removing the clavicle or causing significant chest deformities. These modifications have produced a more predictable transfer compared with other reported techniques.

Creutzfeldt-Jakob disease from allogeneic dura: a review of risks and safety.

Surgeons and the lay public have recently expressed concern over the safety of allogeneic dura as it relates to the transmission of Creutzfeldt-Jakob Disease. Indeed, two cases have resulted from use of tissue procured from a commercial agency that did not adhere to criteria accepted by the American Association of Tissue Banks or the Southeast Organ Procurement Foundation. This review discusses the risks and safety of allogeneic dura. The findings should reassure the surgeon of the safety of allogeneic dura when it is properly processed and catalogued by a bona fide, reputable tissue bank. To date, there have been no documented cases reported to the Center for Disease Control in which Creutzfeldt-Jakob Disease was transmitted from allogeneic dura obtained from a registered tissue bank.

Morbidity from bone harvest in major jaw reconstruction: a randomized trial comparing the lateral anterior and posterior approaches to the ilium.

A randomized prospective study was done to compare bone harvest morbidity in the lateral anterior versus the lateral posterior approach to the ilium. One hundred consecutive patients, requiring at least 60 ml of bone for continuity defects of the mandible, were randomly placed in equal groups in these two categories. Assessment of morbidity vectors included pain, ambulation, seroma, and blood loss. Results, in part, identified the posterior ilium harvest to have decreased morbidity in all variables. The reduced morbidity encountered, and the greater quantity of available bone, are both related to the anatomic differences between the anterior and posterior ilium. Accepted disadvantages were increased operating time and the need to turn the patient.

The sternocleidomastoid muscle as a muscular or myocutaneous flap for oral and facial reconstruction.

The sternocleidomastoid muscle may be used as a muscular or a myocutaneous flap to satisfy the need for viable soft tissue in the reconstruction of some cancer- and trauma-related deformities. The anatomic and technical bases of these flaps are discussed in the context of a single-stage pedicled transfer in oral and maxillofacial reconstructive surgery.

Tissue banking safety: caveats and precautions for the oral and maxillofacial surgeon.

Oral and maxillofacial reconstructive surgeons using allogeneic tissues have expressed justifiable concern over the safety of these tissues as they relate to the transmission of infectious disease. This report reviews cases of infectious disease transmission from inadequately screened donors of allogeneic tissues, as well as those related to improper sterilization and cataloging of these tissues. It is concluded that good judgment and attention to good science on the part of the tissue bank as well as the surgeon can maximize the ability to place contamination-free specimens, thereby avoiding complications similar to those described.

Studies in the radiobiology of osteoradionecrosis and their clinical significance.

The radiobiology of osteoradionecrosis is a complex of cellular death and cellular functional impairments from radiation energy transfers. Four studies of irradiated patients and a data base from 536 patients with osteoradionecrosis revealed separate pathophysiologic conditions for osteoradionecrosis induced by early trauma, osteoradionecrosis induced by late trauma, and spontaneous osteoradionecrosis. A large body of data suggested useful clinical guidelines for the management of irradiated patients. The guidelines, in part, include a recommendation for deferring radiation treatment for 21 days after tissue wounding, if possible; a relative contraindication to wounding tissue during a radiation course; a recommendation for the use of hyperbaric oxygen before wounding; and a strong recommendation to provide comprehensive dental care to the irradiated patient.