Immediate Reconstruction of Mandibular Defects: A Retrospective Report of 242 Cases

J Oral Maxillofac Surg 65:883-890, 2007

Immediate Reconstruction of Mandibular Defects: A Retrospective Report of 242 Cases Zubing Li, DDS, PhD,* Yifang Zhao, DDS, MSc,† Sheng Yao, DDS, MSc,‡ Jihong Zhao, DDS, MSc,§ Shibin Yu, DDS, PhD,储 and Wenfeng Zhang, DDS, MSc¶ Purpose: This study was conducted to evaluate the effects of routine protocols in immediate mandib-

ular reconstruction. Patients and Methods: A total of 242 patients who underwent immediate mandibular reconstruction

were reviewed retrospectively. The therapeutic evaluation was performed according to outcomes of clinical and radiographic examination. The evaluated contents included facial symmetry, degree of mouth opening, occlusal relationship, and temporomandibular joint symptoms. Statistical analysis was also carried out to compare therapeutic differences between different methods for mandibular reconstruction. SPSS 10.0 for Windows was used for statistical analysis. Results: The follow-up showed satisfactory long-term outcome in 203 patients. Statistical analysis revealed no significant difference in restoration of facial contour among several groups (␹2 0.05(15) ⫽ 21.93; P ⫽ .109 ⬎ .05). Ten cases involved serious postoperative complications, including local infection, exposure of rigid fixation plate, and serious pain. Conclusions: Our findings indicate that autogenous bone graft is the best for reconstruction of small mandibular defects. Frozen autogenous lesional mandible plus autogenous iliac or rib graft is recommended for reconstruction of large defects in the mandible. Strict patient selection, careful surgical procedure, and appropriate preoperative and postoperative nursing care are key factors in successful transplantation. © 2007 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 65:883-890, 2007 logical impairment.1 Thus, reconstructive surgery is necessary to restore oral function and speech.2 However, how best to successfully reconstruct mandibular bone defects has not yet been satisfactorily resolved3 and represents a challenge to oral and maxillofacial surgeons.4 Since 1980, a total of 625 patients have undergone immediate mandibular reconstruction using autologous or homologous bone grafts and biomaterials in our department. In this article, we review the findings of clinical and x-ray examination of 242 follow-up cases and evaluate the long-term effects of routine surgical protocols in immediate mandibular reconstruction.

Loss of mandibular continuity, whether caused by tumor, trauma, or infection, produces significant functional disability, cosmetic deformity, and pathoReceived from the Department of Oral and Maxillofacial Surgery, School of Stomatology, Wuhan University, Wuhan, China, and Key Laboratory of Oral Biomedical Engineering (Wuhan University), Ministry of Education, Wuhan, China. *Professor and Chairman. †Professor and Chairman. ‡Formerly, Research Associate; and Currently, Resident, Department of Stomatology, First Hospital of Wuhan, Wuhan, China. §Associate Professor and Chairman. 储Associate Professor and Chairman. ¶Professor and Chairman. Address correspondence and reprint requests to Dr Li: Department of Oral and Maxillofacial Surgery, School of Stomatology, Wuhan University, Key Laboratory of Oral Biomedical Engineering, Wuhan University, Ministry of Education, 237 Luoyu Road, Wuhan, China; e-mail: [email protected]

Materials and Methods GENERAL DATA

A total of 242 patients with mandibular tumor or cyst were included in this retrospective study. The study population comprised 156 males and 86 females, with an age range of 9 to 73 years. The 242 cases included 136 ameloblastomas, 67 keratocysts,

© 2007 American Association of Oral and Maxillofacial Surgeons

0278-2391/07/6505-0010$32.00/0 doi:10.1016/j.joms.2006.06.282

883

884

IMMEDIATE RECONSTRUCTION OF MANDIBULAR DEFECTS SURGICAL PROCEDURES FOR MANDIBULAR RECONSTRUCTION

Table 1. CLASSIFICATION OF MANDIBULAR DEFECTS AND PATHOLOGICAL DIAGNOSIS OF LESIONS

Free Autograft Transplantation After resection of the lesioned mandible, autogenous iliac or rib was harvested according to the size and shape of the defect. Usually, the contralateral seventh or eighth rib or ipsilateral unicortical iliac bone block was harvested. The remaining mandibular segments and autografts were prepared, and “chip grafting” or “graft inlay” was performed by fixing their ends to the remaining mandibular segments (Fig 1).

Classification of Mandibular Defect Pathological Diagnosis

H

L

C

HC

LC

Other Types*

Total

Ameloblastoma Keratocyst Ossifying fibroma Other lesions Total

35 20 4 6 65

75 31 7 11 124

3 4 0 1 8

1 2 2 0 5

17 5 1 3 26

5 5 1 3 14

136 67 15 24 242

*Other types include LCL and HCL.

Transplantation of Autogenous Iliac Crest Plus Rib Grafts Generally, a contralateral rib graft was harvested for reconstruction of the mandibular ramus and condyle process. An ipsilateral iliac crest graft was used to restore defects of mandibular body and angle. Fixation was performed with wires or microplates and screws.

Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

15 ossifying fibromas, and 24 other benign tumors. The defects of 242 cases were classified according to the HCL classification system suggested by Boyd et al.5 In this system, H represents a lateral segment of any length containing a condyle and not significantly crossing the midline, L represents the same defect but without a condyle, and C represents the anterior segment between the incisive foramina. When C must be included in the description, the vast majority of it must compose part of the defect. Taking into account the difficulties in restoring form and function and not simply relying on the traditional anatomic landmarks, the HCL classification system is suggested. The types of mandibular lesions encountered and the classification of mandibular defects are given in Table 1. The 242 cases were classified into 6 groups according to the graft materials used: free autogenous bone transplant (group A), frozen autogenous lesioned mandible (group B), frozen autogenous lesioned mandible–iliac/rib compound (group C), vascularized autogenous bone transplant (group D), homologous bone transplant (group E), and hydroxylapatite (HA)/ titanium plate (group F). General data for each group are given in Table 2.

Reimplantation of Frozen Lesioned Mandible The lesions, soft tissue, and teeth were removed from the resected mandible. The mandibular segment was then hollowed out, and multiple fenestrations were made in the bone surface. The bone segment was immersed in liquid nitrogen (⫺196°C) with 3 freeze–thaw cycles of 10 minutes each, then submerged into an antibiotic solution (400,000 U of gentamycin in saline solution) for 15 minutes. Then the prepared frozen bone segment was reimplanted into the recipient site, and rigid fixation was carried out. Transplantation of frozen autogenous lesioned mandible was performed in combination with autogenous iliac grafting. The lesioned mandible was prepared as described previously. The lesioned mandible and unicortical iliac block were fixed together to augment a weak bone segment and restore the shape of the mandibular body and the height of alveolar ridge. In some cases, the lesioned mandible acted as a proper tray for the packing of marrow and bone chips from the ilium (Fig 2).

Table 2. GENERAL DATA FOR 242 PATIENTS WITH MANDIBULAR DEFECTS

Classification of Mandibular Defect

Group

No. of Cases (Male/Female)

Age (yrs)

Size of Defect (cm)

Mean Size of Defect (cm)

Follow-Up (months)

H

L

C

HC

LC

Other Types*

A B C D E F

95 (64/31) 14 (8/6) 62 (37/25) 27 (15/12) 28 (17/11) 16 (9/7)

9 to 64 11 to 58 9 to 58 14 to 73 10 to 61 18 to 57

6 to 9 4 to 6 5 to 7 3 to 10 3 to 12 8 to 14

7.0 5.0 6.2 6.0 6.4 9.8

14 to 118 19 to 105 14 to 118 37⬃89 45 to 98 20 to 54

27 1 15 8 7 7

55 0 31 14 19 5

2 3 1 1 0 1

2 1 1 0 0 1

6 7 8 3 1 1

3 2 6 1 1 1

*Other types include LCL and HCL. Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

LI ET AL

885 nikov Nevobeef. The surgical procedure for mandibular reconstruction was carried out as described previously. A 2-layer closure was performed after copious irrigation of the graft site (Fig 5). HA Implantation The dense HA block was provided by Western China Medical University. After necessary shape modification, the HA block was inserted into the site of the bone defect and fixed with transosseous wires. Titanium Functional Reconstruction Plate Implantation The titanium functional reconstruction plate was contoured according to the shape of mandible after segmental resection of the mandible. The plate was

FIGURE 1. Free autogenous iliac bone transplantation for mandibular reconstruction. A, Preoperative frontal view (keratocyst of left mandible). B, Frontal view months after operation. C, Radiographic view of keratocyst of left mandible. D, Radiographic view of free autogenous iliac bone transplantation for mandibular reconstruction (6 months after operation). Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

Transplantation of Vascularized Bone The vascularized bone transplantation included iliac bone and fibular bone. After resection of the lesioned mandible, vascularized iliac bone flap or fibular bone flap was harvested according to the size and shape of the defect. The grafts were prepared to adapt to the defect in the mandible. Then the artery and vein of the bone flap were anastomosed with the vessels of the defect site, with the facial artery and external jugular vein and/or facial vein guaranteeing the blood supply. Finally, the graft was fixed to the remaining mandibular segments (Figs 3, 4). Transplantation of Dried Frozen Homologous Bone Grafts The dried frozen homologous bone grafts were kindly provided by a Russian specialist, Professor Plot-

FIGURE 2. Transplantation of frozen antogenous lesioned mandible with autogenous iliac graft for mandibular reconstruction. A, Preoperative frontal view (ameloblastoma of right mandible). B, Frontal view 6 months after operation. C, Radiographic view of ameloblastoma of right mandible. D, Radiographic view of transplantation of frozen antogenous lesioned mandible with autogenous iliac graft (6 months after operation). Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

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IMMEDIATE RECONSTRUCTION OF MANDIBULAR DEFECTS

normal conditions (eg, exposure of rigid fixation plates, infection, dehiscence) occurred. EVALUATION OF THERAPEUTIC RESULTS

On follow-up, clinical and radiographic examinations were performed at l, 3, and 6 months and 1 year after operation, respectively. Restoration of function was performed either through conventional denture use or with an implant-supported prosthesis. Criteria for evaluating the reconstruction performance were based on our department’s guidelines and included facial profile, occlusal relationship, mouth opening, and the condition of the temporomandibular joint (TMJ). Based on these criteria, each reconstruction was classified as Class I, II, III, or IV. In Class I, the patient has a satisfactory and symmetrical facial profile, an almost-normal occlusal relationship, normal mouth opening, and no symptoms of TMJ dysfunction. Class II is characterized by a normal occlusal relationship and no TMJ pain with slight excavation of the operated face and little restriction of mouth opening. Class III involves an asymmetric facial profile and insufficient grafting. Cases involving implant removal are considered Class IV. The ␹2 test, using SPSS 10.0 for Windows (SPSS, Chicago, IL) was performed to compare the differences among groups. In statistical analysis, a P value less than .05 was considered significant.

Results FIGURE 3. Vascularized fibular bone transplant for mandibular reconstruction. A, Preoperative frontal view (ameloblastoma of the left mandible). B, Frontal view 6 months after operation. C, Radiographic view of ameloblastoma of left mandible. D, Radiographic view of vascularized fibular bone transplantion (6 months after operation). Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

then implanted into the defect and fixed to the ends of remaining mandibular segments (Fig 6). NURSING PROCEDURES FOR MANDIBULAR RECONSTRUCTION

Careful and appropriate preoperative and postoperative nursing care was given to all patients. Besides normal nursing procedures (ie, preoperative dental cleaning, postoperative incision cleaning, oral cavity cleaning, and the observation of healing), psychological consolation and sufficient conversation were also included in the nursing care, to help the patients better understand the mandibular reconstruction procedure. Appropriate therapy was provided when ab-

Postoperative follow-up results are summarized in Table 3. Good functional and esthetic results were obtained in most patients (83.88%), with no evidence of recurrence of the primary lesion in all cases. All patients were satisfied with their postsurgical facial contour except for slight disfigurement in 18 cases. Mandibular movement was almost normal in the vast majority of patients. X-ray film revealed that the density of the transplanted grafts appeared to decrease early after operation and gradually became nearly normal. Statistical analysis revealed no significant difference among the different groups (␹2 0.05(15) ⫽ 21.93; P ⫽ .109 ⬎ .05). However, comparison between 2 groups revealed significant differences between groups A and C, groups C and D, and groups C and E. Clinically, the patients in groups A, B, and C achieved satisfactory cosmetic restoration. Frozen autogenous affected mandible plus autogenous lilac or rib graft was particularly suitable for reconstruction of a large range of mandibular defects. Serious postoperative complications, including local infection, exposure of the rigid fixation plate, and serious pain, occurred in 10 patients (Table 4). No

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FIGURE 4. Vascularized iliac bone transplantion. A, Preoperative frontal view (ameloblastoma of left mandible). B, Frontal view 6 months after operation. C, Radiographic view of ameloblastoma of right mandible. D, Radiographic view of vascularized iliac bone transplantion for mandibular reconstruction (6 months after operation). E, F, and G, Tooth implantation after the operation. Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

significant difference in complication rate was found among the various groups.

Discussion Modern studies have shown that mechanisms of bone graft healing include bone conduction and osteoinduction.1,6-9 During bone graft healing, the grafts may act as a supporting framework for the surgical defect and new bone formation. Once the mineral matrix in a block graft resorbs, it is completely replaced by newly formed bone arising from residual host bone through osteoinduction. Both healing mechanisms rely heavily on the cellularity and vascularity of the soft and hard tissues of the recipient site and on the presence of bone morphogenic protein (BMP).1 BMP can induce chondrosoteoblastic differentiation by its action on undifferentiated or protodifferentiated mesenchymal cells.10 This osteoinductive action is directly proportional to the quantity of BMP contained in the graft.11 Periosteum at the recipient site also plays an important role in bone graft

healing.12 Several authors have demonstrated that nontraumatized cancellous bone provides viable mesenchymal cells that produce osteoid shortly after transplantation.13 Our clinical approach to immediate mandibular reconstruction is based on the mechanisms of bone graft healing. Therefore, it is important to describe these mechanisms and help reviewers understand the concepts. The early osteoreparative capacity of a fresh autograft is attributed mainly to abundant osteoblasts in the bone graft itself. In groups B and C, bone grafts serve only as a supporting framework and have no osteogenic capability at an early stage, because the freezing procedure destroys both normal and tumor cells through the formation of ice crystals between the cells, which induces intracellular dehydration, leading to cell death.3 The transplanted bone is gradually replaced by new healthy bone arising from metaplastic osteoblasts in recipient connective tissue. Transplanted HA is finally fixed by fibrous tissue and mineralized bony tissue that enters into the HA millipores without biological degradation.

888

IMMEDIATE RECONSTRUCTION OF MANDIBULAR DEFECTS

Generally, autologous bone grafts are preferred for small defects; however, the addition of homologous bone grafts and biomaterials is normally necessary for large defects.3 Autografts have sufficient bone and nonantigenicity and are easy to perform; they also can integrate quickly with residual mandibular segments. However, obtaining bone autografts entails increased morbidity of the donor site and increased operation time; moreover, there is a limited supply of bone in children.3 In our experience, ipsilateral iliac crest autografts are suitable for reconstructing defects in the mandibular ramus and angle because of a good radian. The ramus height is usually insufficient when the condyle is resected for a tumor and the defect is reconstructed by autogeneous iliac bone graft. Hemimandibular defects can be repaired with rib autografts. Rib transplantation is also a good choice for TMJ reconstruction, because costal cartilage can act as the head of

FIGURE 5. Dried frozen homologous bone grafts for mandibular reconstruction. A, Preoperative frontal view (keratocyst of the right mandible). B, Frontal view 3 months after operation. C, Radiographic view of keratocyst of the right mandible. D, Radiographic view of dried frozen homologous bone grafts for mandibular reconstruction (3 months after operation). Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

In our study, only 10 cases experienced significant postoperative complications. We attribute this low rate of postoperative complications to careful selection of patients and to favorable clinical conditions of the mandibular defects, with no soft tissue defects. Infection (5 cases) was the most common postoperative complication, followed by exposure of the rigid fixation plate. The study variables—age, gender, defect type, and material used for reconstruction— did not differ significantly among the groups. The low number of cases of complications precludes drawing any conclusions about the difference in postoperative complication rate among the various groups.

FIGURE 6. Titanium functional plate insertion for mandibular reconstruction. A, Preoperative lateral view (gingival carcinoma of right mandible). B, Frontal view 1 month after operation. C, Radiographic view of gingival carcinoma of right mandible. D, Radiographic view of titanium functional plate insertion for mandibular reconstruction (1 month after operation). Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

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Table 3. THERAPEUTIC RESULTS FOR 242 PATIENTS AFTER OPERATION

I

II

III

IV

Group

No. of Cases

%

No. of Cases

%

No. of Cases

%

No. of Cases

%

A B C D E F Total

50 9 46 12 12 7 136

52.7 64.3 74.2 44.4 42.9 43.8 56.2

27 4 13 9 8 6 67

28.4 28.6 21.0 33.3 28.6 37.5 27.7

15 1 2 5 6 1 30

15.8 7.1 3.2 18.5 21.4 6.3 12.4

3 0 1 1 2 2 9

3.2 0 1.6 3.8 7.1 12.4 3.7

Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

local toxic and side effects. However, some researchers suggest that this method has several disadvantages, including exfoliation of HA particles,13,14 incomplete integration with recipient bone, lack of osteoinduction capability, extended time for bone healing, pathological fracture, neurosensory deficits, and esthetic changes. Even though dried frozen homologous bone is readily available, currently it is not recommended for extensive application in the clinic setting, because elimination of antigen is a very complicated procedure. A titanium functional reconstruction plate can be used as an alterative method for mandibular reconstruction in older patients with poor health condition or patients with malignant mandibular tumor.15 One drawback of this approach is that the construction plate cannot provide adequate alveolar height for denture construction. Most of the patients in the present study achieved good long-term results. We attribute this success to proper patient selection and careful surgical procedure. Scrupulous nursing care, including preoperative preparation, oral hygiene, and postoperative observation of incisional healing, was also important. The main difference among the various groups lies in the degree of patient satisfaction with restoration

the condyle to avoid ankylosis of the TMJ and resorption of bone after the operation. The rib’s greatest drawback is its lack of bulk. It can be used with iliac transplantation to reconstruct larger mandibular defects. Using frozen autogenous lesioned mandible to reconstruct surgical defects has several advantages. First, the bone graft is autogenous and thus has no antigenicity. Second, a good esthetic result is usually obtained, because the shape of the bone graft coincides with the surgical defect. Especially in the symphyseal area, it is impossible to find a bone within the human skeleton that perfectly fulfills the symphyseal anatomic shape. Finally, the surgery is simplified by avoiding or reducing bone grafts from another part of the body. However, in cases with extensive tumor involvement, this approach should be used cautiously; insufficient supporting soft tissue around the graft bed can lead to infection or necrosis of grafts.5 Progressive resorption of the transplant can also result in pathological fracture; thus, we suggest using this method only in cases with good continuity of lesioned bone. In our study, HA grafts have good histocompatibility without rejecting reaction, as well as general or

Table 4. POSTOPERATIVE COMPLICATIONS

No.

Diagnosis

Complication

Group

Postoperative Day

Type of Defect

1 2 3 4

Ameloblastoma Ossifying fibroma Ameloblastoma Keratocyst

C B A C

3 5 5 7

H H L L

5 6 7

Osteoblastoma Ameloblastoma Keratocyst

Infection Infection Infection Exposure of rigid fixation plate Infection Dehiscence Exposure of rigid fixation plate Ache Dehiscence Infection

A C C

3 7 6

L L LC

A C C

4 6 4

L LC H

8 9 10

Ossifying fibroma Ameloblastoma Keratocyst

Li et al. Immediate Reconstruction of Mandibular Defects. J Oral Maxillofac Surg 2007.

Treatment Antibiotic Antibiotic Antibiotic Removal of plates and refixation Antibiotic Suture Removal of plates and refixation Analgesia Suture Antibiotic

890 of the facial contour. A frozen autogenous lesioned mandible with or without iliac graft can closely coincide with the surgical defect, producing better functional and cosmetic results. As described earlier, nonabsorbable HA has potential side effects and no osteoinductive capability; how best to enhance its osteoinduction necessitates further study.

References 1. Keller EE, Tolman D, Eckert S: Endosseous implant and autogenous bone graft reconstruction of mandibular discontinuity: A 12-year longitudinal study of 31 patients. Int Oral Maxillofac Implants 13:767, 1998 2. Schmelzeisen R, Schon R: Microvascular reanastomosed allogenous iliac crest transplants for the reconstruction of bony defects of the mandible in miniature pigs. Int J Oral Maxillofac Surg 27:377, 1998 3. Redondo LM, Herandez VH, Cantera JMG, et al: Repair of experimental mandibular defects in rats with autogenous, demineralized, frozen and fresh bone. Br J Oral Maxillofac Surg 35:166, 1997 4. Dong YJ, Zhang GZ, Li ZB, et al: The use of immediate frozen autogenous mandible, for benign tumor mandibular reconstruction. Br J Oral Maxillofac Surg 34:58, 1996 5. Boyd JB, Gullane PJ, Rotstein LE, et al: Classification of mandibular defects. Plast Reconstruction Surg 92:1266, 1993

IMMEDIATE RECONSTRUCTION OF MANDIBULAR DEFECTS 6. Stone D, Zacarian SA, Diperi C: Comparative studies of mammalian normal and cancer cells subjected to cryogenic temperature in vitro. J Cryosurg 2:43, 1969 7. Albrektsson T: Repair of bone grafts, a vital microscopic and histologic investigation in the rabbit. Scand J Plast Reconstr Surg 14:1, 1980 8. Reddi AH, Huggins CB: Lactic/malic dehydrogenase quotients during transformation of fibroblasts into cartilage and bone. Proc Soc Exp Bio Med 137:127, 1971 9. Marx RE: Mandibular reconstruction. J Oral Maxillofac Surg 51:466, 1993 10. Mark DE, Hollinger JO, Hastings C, et al: Repair of calvarial nonunions by osteogenin, a bone-inductive protein. Plast Reconstr Surg 86:623, 1990 11. Urist MR, Sato K, Brownell AG, et al: Human bone morphogenetic protein (hBMP). Proc Soc Exp Bio Med 173:194, 1983 12. Abbott LE, Schottstaedt ER, Sannders JB, et al: The evaluation of cortical and cancellous bone as grafting materials: A clinical and experimental study. J Bone Joint Surg 29:381, 1947 13. Mercier P, Bellavance F: Low incidence of severe adverse effects after mandibular ridge reconstruction using hydroxylapatite. Int J Oral Maxillofac Surg 28:273, 1999 14. Wittenberg JM, Small LA: Five-year follow-up of mandibular reconstruction with hydroxylapatite and the mandibular staple bone plate. J Oral Maxillofac Surg 53:19, 1995 15. Dumbach J, Rodemer H, Spitzer WJ, et al: Mandibular reconstruction with cancellous bone, hydroxylapatite and titanium mesh. J Craniomaxillofac Surg 22:151, 1994