**2. Grafts**

are radial forearm flaps for the floor of the mouth defects involving segments of the mandible. Flap selection is based on the quantity and contour of bone required, as well as the volume of soft tissue necessary to accommodate the patient's needs. Whenever possible, it is best to use adjacent soft tissue. If this is not feasible, then a regional flap (e.g., pectoralis major myocuta‐ neous flap or deltopectoral flap) may be required. Reconstruction of mandibular defects requires the use of myocutaneous and microvascular free flaps, in conjunction with osseoin‐ tegrated dental implants, to provide satisfactory masticatory function. The goal of recon‐ structing a tooth-bearing mandible with adequate strength, with appropriate vestibular sulci, and without excessive soft tissue bulk continues to invite surgeons to develop new treatment options. Once the mandibular segments are properly aligned to restore a normal relationship with the maxilla, oral rehabilitation is easily accomplished by a maxillofacial prosthodontist. One area of oromandibular reconstruction that has challenged reconstructive surgeons is the restoration of preoperative sensory and motor functions. Both pedicled and free tissue flaps are large, insensitive tissue blocks that are used to replace oral tissues, thus compromising swallowing and speech mechanisms. It has been difficult to reproduce the complex neurosen‐ sory and muscular activities of the oral and pharyngeal viscera. There is a need for thin, pliable, sensate tissue to facilitate oral rehabilitation. Radial forearm, dorsalis pedis, lateral thigh, lateral arm, and fibular osteocutaneous flaps all possess thin, pliable tissue and identifiable sensory nerves that may be integrated into the reconstructive plan. [4] Urken and Moscoso [13] reported 80% sensory recovery in 40 cases of mandibular reconstruction with radial forearm flaps. Reconstruction of other bony defects typically requires bone grafting (cortical versus cancellous), bone containing vascularized pedicled or free flaps, and free nonvascularized bone grafts. With the advent of rigid fixation, bone grafting techniques have been enhanced, allowing broader applications. Alloplastic materials such as silicone and hydroxyapatite have been used to "fill in" bony defects and not to replace functional and structural tissue loss. The success of bone grafting is completely dependent on adequate stabilization, immobilization, and healthy soft tissue coverage. Once tissue has been irradiated, its repair capacity is compromised. In bone, hypovascularity, damage to osteoprogenitor cells and hypoxic tissue

646 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

When a patient has received doses greater than 5000 rads (50 Gy) after ablative tumor surgery, significant reconstructive difficulties are encountered. Grafts placed into irradiated tissue beds

**Hyperbaric oxygen (HBO)** has been reported to help poorly perfused tissues by allowing hyperoxygenation [14], providing antimicrobial activity (cidal to anaerobes and static to microaerophilic organisms) [15], increasing fibroblastic proliferative activity [16], improving neovascularization and angiogenesis [17], increasing bone matrix formation [18], increasing mineralization [19], promoting osteoclastic activity to remove necrotic bone[20]; and enhanc‐ ing the transport capacity of erythrocytes by increasing their deformability [21]. Ganstrom [22] suggested a protocol for HBO delivery: The patient is seated in a pressurized closed chamber that is above one atmospheric pressure. The patient breathes 100% oxygen, with oxygen toxicity avoided by regulating time and dose limits. Routinely, a single treatment (dive) varies from 90 to 120 minutes once or twice a day. Another protocol developed by Marx'" is as follows:

are responsible.

have high rates of complications.

#### **2.1. Free skin grafting**

Healthy skin grafts usually retain the same color as the donor area and retain the texture and appearance of normal skin (Figure. 1). Skin grafting to the oral cavity has been indicated for the correction of periodontal defects, minor and major preprosthetic defects, and implant surgery, as well as for the reconstruction of traumatic, congenital cleft, and tumor ablative surgery. **Grafts Free Skin Grafting**  Healthy skin grafts usually retain the same color as the donor area and retain the texture and appearance of normal skin (**Figure**. **1**). Skin grafting to the oral cavity has been indicated for the correction of periodontal defects, minor and major preprosthetic defects, and implant surgery, as

well as for the reconstruction of traumatic, congenital cleft, and tumor ablative surgery.

**Figure 1. Free skin graft of the scalp. Figure 1.** Free skin graft of the scalp.

5

Free grafting of the oral mucosa was first described by Propper [23] and was later refined by using mucotome and expanded mesh graft techniques. Skin grafts may be taken from a variety of donor sites. The anterior and lateral aspects of the thigh are frequently used because they can provide a sufficient quantity of graft material using a relatively simple procedure. The buttocks are also used as a donor site when cosmesis is a concern. Full-thickness skin grafts from a retroauricular location are chosen when a good color match is desired for facial reconstruction. For mucosal grafting, the cheek and palate are the two sites most widely used for oral transplantation. Theoretically, the tissue that is intended for reconstruction must closely match the nature of that which was removed. For example, lost periodontal tissues would best be replaced by palatal mucosa, as its thick keratinized nature allows it to withstand the mechanical insults of brushing. Split-thickness skin grafts may be harvested by adjusting the dermatome to control the thickness of the graft and to confine the amount of donor tissue being removed. The desired thickness of the graft is generally dependent on the correct adjustment on the dermatome, manual dexterity, pressure, advancement of the dermatome, and experience. A similar harvest can be Free grafting of the oral mucosa was first described by Propper [23] and was later refined by using mucotome and expanded mesh graft techniques. Skin grafts may be taken from a variety of donor sites. The anterior and lateral aspects of the thigh are frequently used because they can provide a sufficient quantity of graft material using a relatively simple procedure. The buttocks are also used as a donor site when cosmesis is a concern. Full-thickness skin grafts from a retroauricular location are chosen when a good color match is desired for facial reconstruction. For mucosal grafting, the cheek and palate are the two sites most widely used for oral transplantation. Theoretically, the tissue that is intended for reconstruction must closely match the nature of that which was removed. For example, lost periodontal tissues would best be replaced by palatal mucosa, as its thick keratinized nature allows it to withstand the mechanical insults of brushing. Split-thickness skin grafts may be harvested by adjusting

obtained using a scalpel and sharp dissection of the epidermis and dermis from the underlying connective tissues. Oral mucosal grafts from the palate are taken free handed with a scalpel. A Mormann mucotome with a 6-mm blade is also suited for instrumentation. Skin grafts are preferably outlined before injection with a local anesthetic solution. In this way, the tissues are not distorted with the infused solution. If using a dermatome, a donor site with evident capillary bleeding from the dermal layer can be dressed with a Telfa cover sponge impregnated with 1:100,000 epinephrine solution and placed over the site for approximately 10 minutes for hemostatic control. A dressing is then placed to prevent infection and to promote rapid healing. Traditionally, a dressing with petroleum jelly gauze over the donor site works well. There is no need for antibiotics unless there is clinical evidence of infection. When using the free-hand technique for skin graft acquisition, the donor site must be closed primarily, which is relatively easy in the lateral thigh, buttocks, and inguinal regions. The subcutaneous tissues are undermined widely to allow for a tension-free closure. Sutures are placed in the subcutaneous layer, as well as in the skin. There is no need for a drain, provided that dead space has been eliminated using the layered closure. The graft is then placed on a wet gauze towel, which helps prevent folding of the graft edges. A "mesher" can be used to cut multiple slits in the graft to transform it into a lattice, which increases its area two to three times its original size. A meshed graft also has greater pliability to follow irregular contours. The use of slits also creates sites where blood and wound

the dermatome to control the thickness of the graft and to confine the amount of donor tissue being removed. The desired thickness of the graft is generally dependent on the correct adjustment on the dermatome, manual dexterity, pressure, advancement of the dermatome, and experience. A similar harvest can be obtained using a scalpel and sharp dissection of the epidermis and dermis from the underlying connective tissues. Oral mucosal grafts from the palate are taken free handed with a scalpel. A Mormann mucotome with a 6-mm blade is also suited for instrumentation. Skin grafts are preferably outlined before injection with a local anesthetic solution. In this way, the tissues are not distorted with the infused solution. If using a dermatome, a donor site with evident capillary bleeding from the dermal layer can be dressed with a Telfa cover sponge impregnated with 1:100,000 epinephrine solution and placed over the site for approximately 10 minutes for hemostatic control. A dressing is then placed to prevent infection and to promote rapid healing. Traditionally, a dressing with petroleum jelly gauze over the donor site works well. There is no need for antibiotics unless there is clinical evidence of infection. When using the free-hand technique for skin graft acquisition, the donor site must be closed primarily, which is relatively easy in the lateral thigh, buttocks, and inguinal regions. The subcutaneous tissues are undermined widely to allow for a tension-free closure. Sutures are placed in the subcutaneous layer, as well as in the skin. There is no need for a drain, provided that dead space has been eliminated using the layered closure. The graft is then placed on a wet gauze towel, which helps prevent folding of the graft edges. A "mesher" can be used to cut multiple slits in the graft to transform it into a lattice, which increases its area two to three times its original size. A meshed graft also has greater pliability to follow irregular contours. The use of slits also creates sites where blood and wound exudate can escape, providing optimal healing conditions. In order for skin grafting to be successful, graft immo‐ bility is of primary importance, especially during the early healing phase of revascularization. There have been various methods to achieve this goal: sutures, splints, wires, bone screws, and fibrin adhesive. Stents can be produced in advance using conventional dental impression materials and techniques. Ideally, graft immobility should be maintained for 5 to 7 days. Essentially, a graft that is not protected has a greater likelihood of failure. The use of freezedried allergenic grafts has been shown in studies to be comparable to skin grafts for main‐ taining vestibular depth. Lyophilized dura as a wound dressing after periodontal surgery was reported to delay healing time, with subsequent hematoma formation. There have been many similar studies comparing the effectiveness of allografts and xenografts with that of traditional fresh autogenous skin grafts. At present, there are no benefits in using such materials for oral and maxillofacial reconstruction.

#### **2.2. Bone grafting**

When faced with a patient who requires reconstruction of significant hard tissue losses of the mandible, bone grafting is the most viable treatment option. The continuity defect must be prepared with a graft that provides several functions. The principles of bone induction and conduction have been studied extensively over the years. The graft must be able to provide a source of viable osteogenic cells, such that it maintains sufficient osseous bulk and resists resorption for subsequent prosthetic rehabilitation. It must also act as a precursor for bone production and maturation by the bone induction principle. The graft must physically correct any facial form deficiencies resulting from underlying hard tissue losses.

#### *2.2.1. Autogenous bone grafts*

the dermatome to control the thickness of the graft and to confine the amount of donor tissue being removed. The desired thickness of the graft is generally dependent on the correct adjustment on the dermatome, manual dexterity, pressure, advancement of the dermatome, and experience. A similar harvest can be obtained using a scalpel and sharp dissection of the epidermis and dermis from the underlying connective tissues. Oral mucosal grafts from the palate are taken free handed with a scalpel. A Mormann mucotome with a 6-mm blade is also suited for instrumentation. Skin grafts are preferably outlined before injection with a local anesthetic solution. In this way, the tissues are not distorted with the infused solution. If using a dermatome, a donor site with evident capillary bleeding from the dermal layer can be dressed with a Telfa cover sponge impregnated with 1:100,000 epinephrine solution and placed over the site for approximately 10 minutes for hemostatic control. A dressing is then placed to prevent infection and to promote rapid healing. Traditionally, a dressing with petroleum jelly gauze over the donor site works well. There is no need for antibiotics unless there is clinical evidence of infection. When using the free-hand technique for skin graft acquisition, the donor site must be closed primarily, which is relatively easy in the lateral thigh, buttocks, and inguinal regions. The subcutaneous tissues are undermined widely to allow for a tension-free closure. Sutures are placed in the subcutaneous layer, as well as in the skin. There is no need for a drain, provided that dead space has been eliminated using the layered closure. The graft is then placed on a wet gauze towel, which helps prevent folding of the graft edges. A "mesher" can be used to cut multiple slits in the graft to transform it into a lattice, which increases its area two to three times its original size. A meshed graft also has greater pliability to follow irregular contours. The use of slits also creates sites where blood and wound exudate can escape, providing optimal healing conditions. In order for skin grafting to be successful, graft immo‐ bility is of primary importance, especially during the early healing phase of revascularization. There have been various methods to achieve this goal: sutures, splints, wires, bone screws, and fibrin adhesive. Stents can be produced in advance using conventional dental impression materials and techniques. Ideally, graft immobility should be maintained for 5 to 7 days. Essentially, a graft that is not protected has a greater likelihood of failure. The use of freezedried allergenic grafts has been shown in studies to be comparable to skin grafts for main‐ taining vestibular depth. Lyophilized dura as a wound dressing after periodontal surgery was reported to delay healing time, with subsequent hematoma formation. There have been many similar studies comparing the effectiveness of allografts and xenografts with that of traditional fresh autogenous skin grafts. At present, there are no benefits in using such materials for oral

648 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

When faced with a patient who requires reconstruction of significant hard tissue losses of the mandible, bone grafting is the most viable treatment option. The continuity defect must be prepared with a graft that provides several functions. The principles of bone induction and conduction have been studied extensively over the years. The graft must be able to provide a source of viable osteogenic cells, such that it maintains sufficient osseous bulk and resists resorption for subsequent prosthetic rehabilitation. It must also act as a precursor for bone

and maxillofacial reconstruction.

**2.2. Bone grafting**

Autogenous bone is a viable treatment option. It can be particulate cancellous bone marrow, cortical blocks, or a combination of corticocancellous blocks. Particulate bone and cancellous marrow grafts contain numerous osteoprogenitor cells and allow a rapid revascularization. However, owing to their particulate nature, they require some form of containment via either soft tissue envelope-type pockets or rigid mandibular trays. The nonvascular corticocancellous blocks provide structure and bulk. The most common sites for acquisition are the anterior and posterior ilium, rib, and cranial bone. These types of grafts transplant more mineral content rather than osteocompetent cells. When grafting autogenous bone for reconstruction, one must pay close attention to the anatomic detail of the donor site as well as the amount, quality, and contour of bone to be used.

**The iliac crest** is widely accepted because it provides the greatest absolute amount of cancel‐ lous bone volume, as well as providing a cortical plate with significant structure and contour. When approaching the anterior ilium, the position and course of sensory cutaneous innerva‐ tion must be considered. The nerve most often affected in this dissection is the iliohypogastric nerve, which courses over the area of the tubercle. The subcostal nerve traverses over the tip of the anterior superior iliac spine. The lateral femoral cutaneous nerve provides cutaneous sensory innervation to the lateral thigh region. It is located medially between the iliacus and psoas major muscles and then dives deep to the inguinal ligament, piercing the tensor fascia lata muscle. The incisions are therefore made lateral to the crest, avoiding the lateral femoral cutaneous nerve, extending from 2 cm posterior to the iliac tubercle, away from the subcostal nerve, to 1 cm posterior to the anterior superior spine. This places the incision away from the belt and waistband area, preventing excessive impingement. The blood supply to the anterior ilium is from terminal branches of the deep circumflex iliac artery. This lies medially and is avoided in the dissection. A roll is placed under the supinepositioned patient to elevate the iliac crest by lateral rotation at the hip. The patient is then prepped with povidone-iodine (Betadine) soap and paint and draped in a standard sterile fashion. Before sharp dissection, local infiltration of 1 % lidocaine with 1:100,000 epinephrine is used at the planned incision site for its local anesthetic and vasoconstrictive properties. A No. 15 blade is used to make the skin incision, extending to the subcutaneous tissues. Electrocautery is used to gain hemostatic control. The incision can then be manipulated to be centered over the crest. A sharp dissection is completed through the external and internal oblique musculature and periosteal layers to gain access to the bony crest. A subperiosteal reflection of the iliac crest in the medial direction is preferred, to avoid dissection of the tensor fascia lata muscles laterally, creating gait disturbances. Elevation of the iliacus muscle on the medial aspect of the ilium allows adequate access and visualization of the crest for retrieval of the desired bone graft. One must take care in this medial dissection to avoid accidental perforation of the peritoneum and/or bowel. Several osteotomy approaches, with either conventional mallet and osteotomes or air or electrical-driven saw blades, have been described to gain access to the cancellous bone. For small quantities of particulate cancellous bone marrow (PCBM), the "clamshell" approach requires an osteotomy in the midcrestal position to a depth just through the cortical plates. The medial and lateral cortices can be "split" and greensticked apart to allow a route of entry to the cancellous graft. The "trap-door" technique allows access by creating a midline osteot‐ omy and reflecting either medial or lateral cortices, pedicled on adjacent muscles. The "hollowed crest" approach osteotomizes the crest in a horizontal fashion by "de-capping" the crest and reflecting the crest cap laterally to gain access to the central marrow (e.g., Tschapp approach). Finally, Tessier's approach attempts to maintain the contour of the crest by performing oblique osteotomies off the lateral and medial aspects and retrieving the bone deep to the crest itself. If a corticocancellous block is desired, full-thickness osteotomies are com‐ pleted on the medial aspect, detaching the block at the most medial aspect. Once cancellous marrow has been found, bone can be harvested using a 3/8- or 1/2 inch bone gouge and series of curettes. Upon maximal retrieval, closure of the donor sites begins. Any sharp edges are smoothed with bone files. Hemostasis can be achieved with electrocautery of small perforating vessels, placement of bone wax, or microfibrillar bovine collagen (Avitene) to tamponade bleeding. A drain is usually required, exiting at a site away from the incision and suctioned at a low intermittent strength to avoid continuous aspiration of marrow blood. Closure is achieved primarily, first reapproximating periosteal layers with 2-0 Vicryl suture, muscular layers with 4-0 Vicryl suture, subcutaneous tissues with 3-0 chromic gut suture, subcuticular with running, pull-out, and skin with 4-0 nylon/praline suture. A pressure dressing is helpful in the immediate postoperative setting and can be accomplished with cover sponges and foam tape [24].

**Rib** harvesting provides an alternative source of autogenous bone (Figure 2).

At the present time, its primary indication is to reconstruct the mandibular articulation with goodadaptationtothe temporalfossaandreestablishmentoframusheight,andalsotoaugment an atrophic mandible. Depending on size and contour, fourth, fifth, and sixth ribs are best. The sixth rib is most widely used because it can be accessed through an inframammary crease incision. At this level, minimal muscle is transected, as the dissection is between the pectora‐ lis major and rectus abdominis muscles, thus preserving these forfuture muscle flaps. With the patient in the supine position, an inframammary incision is made through the skin and subcutaneous tissues until fibers from the pectoralis major muscle (from above) and rectus abdominismuscle (frombelow)are seenattachingonthe sixthrib.Aperiostealincisionisplaced at the greatest convexity on the lateral aspect of the rib, and with the use of periosteal eleva‐ tors, the rib is exposed from its costochondral junction anteriorly to a posterior length as much as 18 cm. The length is limited posterolaterally by the latissimus dorsi muscle.Careful eleva‐ tion of the periosteum with Molt and Freer elevators is most effective in preventing small tears in the pleura, as small projections of the pleural cortex may tear with the use of large eleva‐ tors. Once reflection is completed, the resection is begun at the cartilage site, taking only 3 mm of cartilagemediallyinbothadultsandchildren.Includingmore than3mmincreases the chance for cartilage separation from bone, especially in children. Once the anterior end is separated from the sternum, the rib can be elevated by placing an instrument on the undersurface of the rib, protecting the parietal pleura as the posterior extent is reached. The posterior end is then cut, and the host end is smoothed with files. At this time, it is prudent to evaluate the pleura for tears. This can be done either visually or with the use of saline irrigation; the latter produces air bubbles if an air leak is present. Closure begins with periosteal approximation, followed by a muscle layer, subcutaneous tissue layer, and skin. Drains are usually not indicated. In chil‐ dren, a full morphologically normal rib will regenerate within 1 year, whereas in adults, an incomplete bone ossicle resembling a rib slowly forms over 1 to 3 years. [25]

Calvarial bone grafting for oral and maxillofacial surgery has progressed since its described use by Harsha and colleagues [26]. It has been widely used for vertical augmentation of maxilla and reconstruction of orbital wall and floor defects. It has a unique characteristic of early revascularization, which is directly related to the numerous vascular systems. As a result, the graft survives with little dimensional change. The paramedian portion of the parietal bone is the most likely area for harvest because it is the thickest, it is away from any vital structures (e.g., the superior sagittal sinus), and there is less chance that the scar will be visible in patients with male pattern baldness. The approach to this area requires a hemicoronal or bicoronal incision, posterior to the ear, and is carried through the five scalp layers (skin, subcutaneous tissues, galea-aponeurotic layer, loose connective tissue, and periosteum). Bleeding skin vessels are hemostatically controlled with Raney clips. The use of electrocoagulation may destroy hair follicles and result in patchy alopecia. A bur is used to create the shape of the desired graft in the outer cortex to the level of the cancellous marrow. Then, with the use of curved osteotomes, the outer table can be cleaved from the inner table in the plane of the interposed cancellous marrow. The incision is closed primarily in layers. Pressure dressings with "crani-caps" are placed to allow adaptation of the elevated tissues to bony scalp.

**Figure 2.** Rib harvesting

small quantities of particulate cancellous bone marrow (PCBM), the "clamshell" approach requires an osteotomy in the midcrestal position to a depth just through the cortical plates. The medial and lateral cortices can be "split" and greensticked apart to allow a route of entry to the cancellous graft. The "trap-door" technique allows access by creating a midline osteot‐ omy and reflecting either medial or lateral cortices, pedicled on adjacent muscles. The "hollowed crest" approach osteotomizes the crest in a horizontal fashion by "de-capping" the crest and reflecting the crest cap laterally to gain access to the central marrow (e.g., Tschapp approach). Finally, Tessier's approach attempts to maintain the contour of the crest by performing oblique osteotomies off the lateral and medial aspects and retrieving the bone deep to the crest itself. If a corticocancellous block is desired, full-thickness osteotomies are com‐ pleted on the medial aspect, detaching the block at the most medial aspect. Once cancellous marrow has been found, bone can be harvested using a 3/8- or 1/2 inch bone gouge and series of curettes. Upon maximal retrieval, closure of the donor sites begins. Any sharp edges are smoothed with bone files. Hemostasis can be achieved with electrocautery of small perforating vessels, placement of bone wax, or microfibrillar bovine collagen (Avitene) to tamponade bleeding. A drain is usually required, exiting at a site away from the incision and suctioned at a low intermittent strength to avoid continuous aspiration of marrow blood. Closure is achieved primarily, first reapproximating periosteal layers with 2-0 Vicryl suture, muscular layers with 4-0 Vicryl suture, subcutaneous tissues with 3-0 chromic gut suture, subcuticular with running, pull-out, and skin with 4-0 nylon/praline suture. A pressure dressing is helpful in the immediate postoperative setting and can be accomplished with cover sponges and foam

650 A Textbook of Advanced Oral and Maxillofacial Surgery Volume 2

**Rib** harvesting provides an alternative source of autogenous bone (Figure 2).

At the present time, its primary indication is to reconstruct the mandibular articulation with goodadaptationtothe temporalfossaandreestablishmentoframusheight,andalsotoaugment an atrophic mandible. Depending on size and contour, fourth, fifth, and sixth ribs are best. The sixth rib is most widely used because it can be accessed through an inframammary crease incision. At this level, minimal muscle is transected, as the dissection is between the pectora‐ lis major and rectus abdominis muscles, thus preserving these forfuture muscle flaps. With the patient in the supine position, an inframammary incision is made through the skin and subcutaneous tissues until fibers from the pectoralis major muscle (from above) and rectus abdominismuscle (frombelow)are seenattachingonthe sixthrib.Aperiostealincisionisplaced at the greatest convexity on the lateral aspect of the rib, and with the use of periosteal eleva‐ tors, the rib is exposed from its costochondral junction anteriorly to a posterior length as much as 18 cm. The length is limited posterolaterally by the latissimus dorsi muscle.Careful eleva‐ tion of the periosteum with Molt and Freer elevators is most effective in preventing small tears in the pleura, as small projections of the pleural cortex may tear with the use of large eleva‐ tors. Once reflection is completed, the resection is begun at the cartilage site, taking only 3 mm of cartilagemediallyinbothadultsandchildren.Includingmore than3mmincreases the chance for cartilage separation from bone, especially in children. Once the anterior end is separated from the sternum, the rib can be elevated by placing an instrument on the undersurface of the rib, protecting the parietal pleura as the posterior extent is reached. The posterior end is then

tape [24].

Rigid plate fixation [27] has resolved the problems with nonunion, but resorption continues to occur due to the stress shielding. Branemark and colleagues [28] in 1975 first reported the successful use of a block bone graft stabilized by a titanium plate in traumatic cases. Rigid plates have been well adapted to the preselected mandible to achieve the functional contours necessary for reconstruction. Li and associates [29] established a technique to maintain mandibular position with respect to the temporomandibular joint. Before resection, the mandible is placed in maximal intercuspation, with condyles seated firmly in the fossa.

Miniplates and screws are spanned bilaterally from the maxillary zygomatic processes to the mandibular ascending ramus. The plate is then adapted to the contour of the existing mandible, and the resection takes place. In this technique, the posterior facial height is maintained, as well as accurate adaptation of the condyle to the fossa. Ardary [30] also commented on the importance of adequately stabilizing the free bone graft with the use of a mandibular recon‐ struction plate in a report of nine consecutive cases with successful results. Absolute stability promotes neovascularization of the graft by permitting vascular ingrowth while simultane‐ ously allowing for immediate postsurgical jaw function. Boyne [31] compared segmental defects in dogs that were bridged together with block bone or stabilized with a plate or with particulate bone and marrow within a Vitallium tray. He found significant resorption with the block bone, whereas complete bony regeneration and union were evident when the PCBM and tray were used. Dacron urethane mandibular trays were used with autogenous iliac crest bone in one study that showed retention of 80% of bony height over a 3-year period, with little alteration in the complication rate compared with standard reconstructive techniques [32]. The Dacron tray is a lightweight, biologically inert structure that is easy to adapt to the mandible, requiring a more limited access. Its radiolucency allows one to appreciate the radiographic monitoring of the bone graft. And, finally, reconstruction of the bone graft with fixation plates and metallic trays requires a second surgical procedure before endosseous dental implant placement, whereas the Dacron tray does not require removal. Mandibular reconstruction with reimplantation of resected mandibles that are hollowed out and function like a tray has been studied by Jisander and coworkers [33]. The prepared segments act as a matrix for new bone formation and as a carrier for transplanted cancellous bone. [34].

#### *2.2.2. Allogenic bone grafts*

Allogenic grafts are those taken from the same species but transplanted into a different individual. [35]. The major disadvantage of FFB is the small risk of disease transmission. [36] Bone substitutes, or alloplastic materials, have been used to recontour alveolar defects and as extenders in bone graft systems for reconstruction of major continuity defects. One such substitute is hydroxyapatite. It does not have the mechanical properties necessary for recon‐ structing major defects but provides a temporary matrix for future bone growth because of its osteoconductive nature.

Xenografts of bone and cartilage such as bovine bone mineral have been used as fillers or spacers in orthognathic and preprosthetic surgeries, as well as sinus grafting procedures (Figure 3) and alloplastic trays are commonly used to bridge the gap and to carry PCBM to fill mandibular defects. Its drawback is the risk of disease transmission. The Dacron-coated polyurethane crib is flexible, lightweight, biologically inert, easy to trim and adapt to the mandible, and radiolucent, which allows assessment of postoperative bone graft healing. Its disadvantages include its reliability in long-span mandibular defects, where intermaxillary fixation or internal reinforced metal rods are used for added rigidity.

an anterior base for lower lip reconstruction. A combination of both types of flaps can be incorporated to reconstruct vermilion and lining. The only drawback in creating these flaps is the

 **Ventral-based flaps** have been described for repairs of anterior floor of the mouth defects, where two parallel lengthwise posterior-based flaps are reflected and rotated to the anterior defect. The resultant donor site cannot be closed primarily because of obvious contraction of the tongue. In this case, a skin graft can be placed to cover the donor site and is in fact well tolerated, with minimal effect on tongue mobility. This flap also has good results for vermilion

resultant shortening of the tongue, which may affect speech and swallow mechanisms.

reconstruction [38] ( **Figure 4**)

**Figure 3.** Polyurethane crib (left), alveolar bone grafting (right)

11 Metallic alloplastic trays have the ability to maintain the normal relationship of the residual mandibular segment without additional fixation, so the patient resumes normal functions earlier. The titanium tray is harder than the Dacron tray but softer than cobalt-chromium and stainless steel trays. The disadvantages of metallic cribs are that they have very high flanges in order to carry an adequate volume of bone, thus interfering with preprosthetic procedures and dental prostheses. This leads to tray removal. A simple technique was recently reported by Tayapongsak and coworkers [37] in designing a custom-made inferior border titanium crib (IBTC). The disadvantages of the custom-made IBTC are the use of intermaxillary fixation and its nonresorptive ability.
