CLINICAL STUDY
Sagittal Split Osteotomy on the Previously Reconstructed Mandible With Fibula Free Flap Jin-Wook Kim, DDS, PhD,* Cheong-Hee Lee, DDS, PhD,† and Tae-Geon Kwon, DDS, PhD* Abstract: The fibula free flap offers several advantages in mandibular reconstruction, including an optimal length and bone quality for dental implantation; therefore, the use of this flap has become a method of choice for mandibular reconstruction. Although the development of computer-assisted surgical planning has increased the accuracy of mandibular reconstruction, some unexpected outcomes still occur in clinical settings. The patient in this report underwent mandibular reconstruction with the fibula free flap because of mandibular resection resulting from an ameloblastoma. However, unexpected movement of the grafted fibula bone had been observed, and we could not achieve a proper occlusal relationship even with implant-supported prosthesis. To resolve this problem, we corrected the position of previously grafted fibula and implants by using orthognathic surgery: sagittal split osteotomy on body and angle area and vertical osteotomy on the mandibular symphysis. After the orthognathic surgery at the previously reconstructed mandible with fibula free flap, a favorable and stable occlusal relationship could be achieved. The result demonstrated that the sagittal split osteotomy at the previous fibula free flap site can be successfully carried out to establish the proper occlusion. Key Words: Ameloblastoma, mandibular reconstruction, fibula free flap, sagittal split osteotomy (J Craniofac Surg 2014;25: 1833–1835)
T
he mandible is essential for proper occlusion, mastication, deglutition, and speech. The degree of the functional and esthetic deficit after mandibular resection depends upon the location and amount of the removed mandible. The most common reason for mandibular resection is ablative surgery for large neoplasms involving the mandible, such as ameloblastomas.1,2 An extensive ameloblastoma sometimes requires segmental mandibular resection or hemimandibulectomy.3 Reconstruction of these mandibular defects is challenging, and various reconstruction methods are required to achieve functional and esthetic rehabilitation. The fibula free flap offers several advantages in mandibular reconstruction, including the availability of a long segment of bone (20–26 cm), a
From the Departments of *Oral and Maxillofacial Surgery, and †Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea. Received February 25, 2014. Accepted for publication April 23, 2014. Address correspondence and reprint requests to Tae-Geon Kwon, DDS, PhD, Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Samduck 2 Ga, Jung Gu, Daegu 700-421, Republic of Korea; E-mail: [email protected] Supported by Kyungpook National University Research Fund, 2012. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001058
reasonably long vascular pedicle with large-diameter vessels, good bone quality, and an ability to contour the bone with multiple osteotomies. Therefore, the fibula free flap has become the method of choice for mandibular reconstruction.4,5 Although the recent development of computer-assisted surgical planning enables more accurate mandibular reconstruction,6–8 some unexpected outcomes of improper positioning of bone segments do occur in clinical settings. In the case presented here, the patient had undergone mandibular reconstruction surgery with the fibula free flap followed by dental implant fixation because of mandibular resection necessitated by a large ameloblastoma. Although the flap and the dental implant were successfully maintained several months after surgery, dental rehabilitation was impossible because of an improper occlusal relationship resulting from the unexpected movement of the grafted fibula bone and the remaining ramus-condyle unit (RCU). The purposes of this case report were to present our technique for correcting the improper occlusal relationship and facial asymmetry after mandibular reconstruction with the fibula free flap and to discuss the feasibility of orthognathic surgery at the previously grafted site.
PATIENTS AND METHODS A 31-year-old woman first visited the authors' affiliated hospital in December 2005. The patient complained of pain on palpation of the left molar area. In a panoramic radiograph, a multilocular radiolucent lesion with a hyperostotic and scalloped border and clearly resorbed roots of the left lower premolars and the first molar near the lesion were observed. An incisional biopsy of the lesion was performed, and an ameloblastoma was identified on the basis of the findings of histopathologic studies. However, the patient declined the treatment and did not return to our department for 4 years. When the patient was reexamined in July 2009, the chief complaint was an esthetic problem resulting from an enlarged left mandible. In a panoramic radiograph and enhanced computed tomographic scan, the lesion had increased in size and extended to the left first incisor anteriorly and the third molar posteriorly. Thinning and expansion of the buccolingual cortical bone were more severe, and several perforations of the cortical bone were observed (Fig. 1A). Mandibular resection extending from the symphysis to the left angle area and reconstruction with the fibula free flap were planned. An angiogram of the lower extremity indicated that there were no abnormalities in the vascular anatomy. In September 2009, a 2-team approach for primary lesion resection and right fibula free flap harvesting was used. An extended submandibular incision on the left side of the neck was used. Mandibular resection including the symphysis to the left angle area was completed, and the left inferior alveolar nerve was killed (Fig. 1B). The technique for harvesting the right fibula free flap was based on the classic description.9,10 The skin flap size was 5 2.5 cm, and it included 2 perforators. The harvested fibula osteocutaneous free flap was fixed with a prebended mandibular reconstruction plate before surgery according to the rapid prototype model (Fig. 1C). Intermaxillary fixation was applied for 1 week. Postoperative
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1833
Kim et al
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
FIGURE 1. A, Preoperative panoramic radiograph showed the osteolytic lesion extending from the incisor to the third molar and severe resorption of roots, bony expansion, and thinning of the inferior border. B, Resected mandible from the incisor to the left mandibular angle. Periosteum and soft tissue were included on buccolingual cortical bone. C and D, Fibula free flap was fixed onto a prebended reconstruction plate. Postoperative panoramic radiograph with tracing drawn was preoperatively. The fibula free flap was positioned on the inferior border; in the mandibular area, the proximal part of the fibula bone is fixed at a lower position than the original position.
progress was uneventful. In the postoperative panoramic radiograph, the angle between the fibula and the remaining RCU was 125 degrees and was acceptable compared with the preoperative status angle of 120 degrees (Fig. 1D). However, approximately 3 months after the surgery, the angle between the fibula and the RCU increased to 139 degrees, and 6 months later, it increased to 144 degrees. Consolidation of the fibula had progressed normally, and there was no radiographic evidence indicating screw loosening. Although there was a change in the fibula free flap, the patient's mouth-opening ability and mandibular movement were normal, so the patient wanted to restore the dentition. Fourteen months after the ablative surgery with microsurgical reconstruction, the reconstruction plate had been removed and 3 dental implants were installed to the previously grafted fibula. To improve the bilateral asymmetry, the iliac bone was grafted to the inferior border of the left mandibular body area. Because the fibula position was not optimal, implant position was not suitable for a favorable occlusal relationship (Fig. 2A). Therefore, the orthognathic surgery for grafted fibula with dental implants had been carried out (Figs. 2B, C). The detailed design of the surgical procedure is illustrated in Figure 3. We decided to perform sagittal splitting of the previously grafted fibula (Fig. 3A). After performing model surgery with a cast, a temporary implant-supported prosthesis was fabricated to ideally position the mandible to the favorable occlusion. Thus, the implant prosthesis served as a guide for reosteotomized fibula segments. Sagittal split osteotomy was performed on the grafted fibula bone. To improve intraoperative and postoperative occlusal stability, an occlusal splint was also constructed on the model surgery cast. In November 2011, the temporary implant prostheses were connected to implants before surgery. We retained the position of the left RCU by using a condyle positioning plate. A sagittal split osteotomy was performed at the fibula bone located at the mandibular body and angle area. An additional vertical osteotomy on the symphysial area of the fibula-mandibular interface had been performed (Fig. 3B). After repositioning of the temporary prostheses on the dental implants and the free fibula bone by using a surgical splint and intermaxillary fixation screws, proximal RCU was positioned with the condyle positioning plate. The osteotomized fibula bone was fixed with miniplates (Figs. 3C, D). One week after the surgery, the intermaxillary fixation was removed. There was no further movement of the fibula bone postoperatively. Six months after the orthognathic surgery at the fibula, the
1834
FIGURE 2. A, The reconstruction plate had been removed, and 3 dental implants were installed to the previously grafted fibula 14 months after the initial surgery with microsurgical reconstruction. To improve the bilateral asymmetry, the iliac bone was grafted to the inferior border of the left mandibular body area. Compared with preoperative outline (line), the movement of the fibula and the RCU resulted in a flattening of the angle area. B, The fibular segments were osteotomized by using the sagittal split osteotomy, and the fibular-mandibular junction at the symphysis was vertically osteotomized to correct the improper occlusal table position and facial asymmetry. C, Eighteen months after the sagittal splitting of the grafted fibula, there was favorable bony healing without significant RCU movement.
final prostheses were connected after the surgery, and the postoperative stability was favorable.
DISCUSSION Mandibular resection surgeries with remaining large bone defect can be successfully managed by fibula free flap since previous reports from Taylor et al9 and Hidalgo.10 Currently, minimization of the
FIGURE 3. A, A three-dimensional computed tomographic image shows the sagittal split ramus osteotomy bony cutting line on the ramus and the fibula bone and the symphysis cutting line (white line). B, After the orthognathic surgery, the fibula was successfully repositioned, and the asymmetric mandibular shape was improved. C, Immediately before orthognathic surgery, a temporary surgical prosthesis was fabricated to guide the fibula to the optimal position. D, After orthognathic surgery, a favorable occlusal relationship could be achieved.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
surgical error is directly related to surgical outcomes such as esthetics and functional recovery. Therefore, predicting the length of the fibula, determining the cutting angle before surgery, creating a surgical template for mandibular resection, and preserving mandibular position are more important. We also used the rapid prototype model, which helps to estimate resection margins and reconstruction plates that hold the remaining mandibular position and fibula contour to minimize surgical error and operation time. However, in this case, the left mandibular angle gradually developed into an obtuse angle, and the vertical occlusal dimension decreased a long period after the surgery. The reason for this remarkable positional change of the segments even under the rigid fixation with a reconstruction plate needs explanation. We propose the following possible contributing factors. First, we suspected that decreased bony contact may have affected the bony change. During surgery, the fibula bone was fixed at a lower position than the original position of the mandibular body. Then, the overall height of the ramus was increased, and the bony contact between the fibula and the remaining mandible was decreased. This might be attributed to low bony stability. Second, pulling of the masseteric sling may have resulted in bony changes. Increased vertical height leads to increasing tension of the masseteric sling. We used a reconstruction plate to maintain the mandible and the grafted fibula, and in the follow-up radiographic examination, there was no screw loosening. Therefore, the obtuse change in the mandibular angle likely resulted from the increased pulling of the masseteric sling. In addition, movement of the mandibular angle in the anterior-medio-superior direction, which is the same direction as the masseteric sling action, was observed in the series of panoramic and anterior-posterior plane radiographs. Third, absence of early recovery of occlusal height may have been a factor contributing to bony change. Proper treatment for maintaining vertical occlusal height, such as temporary dentures, early implant insertion, and superior prostheses, was not applied during the early stage. Some reports indicate that immediate functional implant and screw-secured fixed prosthesis serve as an external fixator for the implants and grafted bone.11,12 However, we started occlusal rehabilitation with implant insertion after 14 months. During this period, continuous reduction of the vertical dimension and flattening of the mandibular angle might continue to occur. To circumvent postoperative malocclusion after fibula free flaps, osteotomies onto the reconstruction sites had been reported by Chang et al13 (2003) and Gennaro et al14 (2010). In these previous reports, the junction of the fibula and the native mandibular bone was osteotomized to reposition the fibula.13 The step osteotomy on the fibula free flap was applied to improve sagittal or vertical height defect.14 In our case, fibula segments were osteotomized by using the sagittal split osteotomy, and the fibula-mandibular junction at the symphysis was vertically osteotomized to correct the improper occlusal table position and facial asymmetry. Use of the sagittal split osteotomy for the previously grafted fibula has several advantages. Realignment of grafted segment with vertical13 or step osteotomy14 can result in significant horizontal or vertical interbony gap that can result in unstable final occlusion a long period after surgery. Sagittal split osteotomy can ensure better osseous contact surface between the proximal and the distal bone to allow faster bone healing. Especially, when the grafted segments need to be mobilized buccolingually or need to be rotated from the original position, vertical or step osteotomy onto the long and slender fibula can result in the absence
Orthognathic Surgery at the Fibular Flap
of bony contact. Therefore, sagittal split osteotomy of the fibula including the ramus such as conventional sagittal split ramus osteotomy would be the better option to simplify the surgery, increase bony contact for healing, maximize bony stability after surgery, move the occlusal table of the fibula bone to the proper position, and improve the facial asymmetry. In our case of mandibular reconstruction with a fibula free flap after mandibular resection, the grafted fibula bone and host mandible moved to an unexpected position because of masseteric pulling and a lack of bony stability. This resulted in an improper change of occlusal table for dental implant and aggravation of facial asymmetry. We corrected these problems with a sagittal split osteotomy on the grafted fibula similar to a sagittal split ramus osteotomy for mandibular deformity. The experience of our study highlighted the feasibility of sagittal split of the previously grafted site, and applying the concept of orthognathic surgery would be a successful treatment option for correction of malpositioned graft site by microvasular reconstruction.
REFERENCES 1. Schusterman MA, Harris SW, Raymond AK, et al. Immediate free flap mandibular reconstruction: significance of adequate surgical margins. Head Neck 1993;15:204–207 2. Tamme T, Tiigimäe J, Leibur E. Mandibular ameloblastoma: a 28-years retrospective study of the surgical treatment results. Minerva Stomatol 2010;59:637–643 3. Chana JS, Chang YM, Wei FC, et al. Segmental mandibulectomy and immediate free fibula osteoseptocutaneous flap reconstruction with endosteal implants: an ideal treatment method for mandibular ameloblastoma. Plast Reconstr Surg 2004;113:80–87 4. Jones NF, Swartz WM, Mears DC, et al. The “double barrel” free vascularized bone graft. Plast Reconstr Surg 1998;81:378–385 5. Abou-ElFetouh A, Barakat A, Abdel-Ghany K. Computer-guided rapid-prototyped templates for segmental mandibular osteotomies: a preliminary report. Int J Med Robot 2011;7:187–192 6. Schrag C, Chang YM, Tsai CY, et al. Complete rehabilitation of the mandible following segmental resection. J Surg Oncol 2006;94: 538–545 7. Bell RB, Weimer KA, Dierks EJ, et al. Computer planning and intraoperative navigation for palatomaxillary and mandibular reconstruction with fibular free flaps. J Oral Maxillofac Surg 2011;69:724–732 8. Roser SM, Ramachandra S, Blair H, et al. The accuracy of virtual surgical planning in free fibula mandibular reconstruction: comparison of planned and final results. J Oral Maxillofac Surg 2010;68:2824–2832 9. Taylor GI, Miller GD, Ham FJ. The free vascularized bone graft. A clinical extension of microvascular techniques. Plast Reconstr Surg 1975;55:533–544 10. Hidalgo DA. Fibula free flap: a new method of mandible reconstruction. Plast Reconstr Surg 1985;84:71–79 11. Odin G, Balaguer T, Savoldelli C, et al. Immediate functional loading of an implant supported fixed prosthesis at the time of ablative surgery and mandibular reconstruction for squamous cell carcinoma. J Oral Implantol 2010;36:225–230 12. Sclaroff A, Haughey B, Gay WD, et al. Immediate mandibular reconstruction and placement of dental implants. At the time of ablative surgery. Oral Surg Oral Med Oral Pathol 1994;78:711–777 13. Chang YM, Chana JS, Wei FC, et al. Osteotomy to treat malocclusion following reconstruction of the mandible with the free fibula flap. Plast Reconstr Surg 2003;112:31–36 14. Gennaro P, Torroni A, Leonardi A, et al. Role of a new orthognathic surgery in maxillomandibular reconstruction by free flaps. J Craniofac Surg 2010;21:1238–1240
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1835
Sagittal Split Osteotomy on the Previously Reconstructed Mandible With Fibula Free Flap Jin-Wook Kim, DDS, PhD,* Cheong-Hee Lee, DDS, PhD,† and Tae-Geon Kwon, DDS, PhD* Abstract: The fibula free flap offers several advantages in mandibular reconstruction, including an optimal length and bone quality for dental implantation; therefore, the use of this flap has become a method of choice for mandibular reconstruction. Although the development of computer-assisted surgical planning has increased the accuracy of mandibular reconstruction, some unexpected outcomes still occur in clinical settings. The patient in this report underwent mandibular reconstruction with the fibula free flap because of mandibular resection resulting from an ameloblastoma. However, unexpected movement of the grafted fibula bone had been observed, and we could not achieve a proper occlusal relationship even with implant-supported prosthesis. To resolve this problem, we corrected the position of previously grafted fibula and implants by using orthognathic surgery: sagittal split osteotomy on body and angle area and vertical osteotomy on the mandibular symphysis. After the orthognathic surgery at the previously reconstructed mandible with fibula free flap, a favorable and stable occlusal relationship could be achieved. The result demonstrated that the sagittal split osteotomy at the previous fibula free flap site can be successfully carried out to establish the proper occlusion. Key Words: Ameloblastoma, mandibular reconstruction, fibula free flap, sagittal split osteotomy (J Craniofac Surg 2014;25: 1833–1835)
T
he mandible is essential for proper occlusion, mastication, deglutition, and speech. The degree of the functional and esthetic deficit after mandibular resection depends upon the location and amount of the removed mandible. The most common reason for mandibular resection is ablative surgery for large neoplasms involving the mandible, such as ameloblastomas.1,2 An extensive ameloblastoma sometimes requires segmental mandibular resection or hemimandibulectomy.3 Reconstruction of these mandibular defects is challenging, and various reconstruction methods are required to achieve functional and esthetic rehabilitation. The fibula free flap offers several advantages in mandibular reconstruction, including the availability of a long segment of bone (20–26 cm), a
From the Departments of *Oral and Maxillofacial Surgery, and †Prosthodontics, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea. Received February 25, 2014. Accepted for publication April 23, 2014. Address correspondence and reprint requests to Tae-Geon Kwon, DDS, PhD, Department of Oral and Maxillofacial Surgery, School of Dentistry, Kyungpook National University, Samduck 2 Ga, Jung Gu, Daegu 700-421, Republic of Korea; E-mail: [email protected] Supported by Kyungpook National University Research Fund, 2012. The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001058
reasonably long vascular pedicle with large-diameter vessels, good bone quality, and an ability to contour the bone with multiple osteotomies. Therefore, the fibula free flap has become the method of choice for mandibular reconstruction.4,5 Although the recent development of computer-assisted surgical planning enables more accurate mandibular reconstruction,6–8 some unexpected outcomes of improper positioning of bone segments do occur in clinical settings. In the case presented here, the patient had undergone mandibular reconstruction surgery with the fibula free flap followed by dental implant fixation because of mandibular resection necessitated by a large ameloblastoma. Although the flap and the dental implant were successfully maintained several months after surgery, dental rehabilitation was impossible because of an improper occlusal relationship resulting from the unexpected movement of the grafted fibula bone and the remaining ramus-condyle unit (RCU). The purposes of this case report were to present our technique for correcting the improper occlusal relationship and facial asymmetry after mandibular reconstruction with the fibula free flap and to discuss the feasibility of orthognathic surgery at the previously grafted site.
PATIENTS AND METHODS A 31-year-old woman first visited the authors' affiliated hospital in December 2005. The patient complained of pain on palpation of the left molar area. In a panoramic radiograph, a multilocular radiolucent lesion with a hyperostotic and scalloped border and clearly resorbed roots of the left lower premolars and the first molar near the lesion were observed. An incisional biopsy of the lesion was performed, and an ameloblastoma was identified on the basis of the findings of histopathologic studies. However, the patient declined the treatment and did not return to our department for 4 years. When the patient was reexamined in July 2009, the chief complaint was an esthetic problem resulting from an enlarged left mandible. In a panoramic radiograph and enhanced computed tomographic scan, the lesion had increased in size and extended to the left first incisor anteriorly and the third molar posteriorly. Thinning and expansion of the buccolingual cortical bone were more severe, and several perforations of the cortical bone were observed (Fig. 1A). Mandibular resection extending from the symphysis to the left angle area and reconstruction with the fibula free flap were planned. An angiogram of the lower extremity indicated that there were no abnormalities in the vascular anatomy. In September 2009, a 2-team approach for primary lesion resection and right fibula free flap harvesting was used. An extended submandibular incision on the left side of the neck was used. Mandibular resection including the symphysis to the left angle area was completed, and the left inferior alveolar nerve was killed (Fig. 1B). The technique for harvesting the right fibula free flap was based on the classic description.9,10 The skin flap size was 5 2.5 cm, and it included 2 perforators. The harvested fibula osteocutaneous free flap was fixed with a prebended mandibular reconstruction plate before surgery according to the rapid prototype model (Fig. 1C). Intermaxillary fixation was applied for 1 week. Postoperative
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1833
Kim et al
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
FIGURE 1. A, Preoperative panoramic radiograph showed the osteolytic lesion extending from the incisor to the third molar and severe resorption of roots, bony expansion, and thinning of the inferior border. B, Resected mandible from the incisor to the left mandibular angle. Periosteum and soft tissue were included on buccolingual cortical bone. C and D, Fibula free flap was fixed onto a prebended reconstruction plate. Postoperative panoramic radiograph with tracing drawn was preoperatively. The fibula free flap was positioned on the inferior border; in the mandibular area, the proximal part of the fibula bone is fixed at a lower position than the original position.
progress was uneventful. In the postoperative panoramic radiograph, the angle between the fibula and the remaining RCU was 125 degrees and was acceptable compared with the preoperative status angle of 120 degrees (Fig. 1D). However, approximately 3 months after the surgery, the angle between the fibula and the RCU increased to 139 degrees, and 6 months later, it increased to 144 degrees. Consolidation of the fibula had progressed normally, and there was no radiographic evidence indicating screw loosening. Although there was a change in the fibula free flap, the patient's mouth-opening ability and mandibular movement were normal, so the patient wanted to restore the dentition. Fourteen months after the ablative surgery with microsurgical reconstruction, the reconstruction plate had been removed and 3 dental implants were installed to the previously grafted fibula. To improve the bilateral asymmetry, the iliac bone was grafted to the inferior border of the left mandibular body area. Because the fibula position was not optimal, implant position was not suitable for a favorable occlusal relationship (Fig. 2A). Therefore, the orthognathic surgery for grafted fibula with dental implants had been carried out (Figs. 2B, C). The detailed design of the surgical procedure is illustrated in Figure 3. We decided to perform sagittal splitting of the previously grafted fibula (Fig. 3A). After performing model surgery with a cast, a temporary implant-supported prosthesis was fabricated to ideally position the mandible to the favorable occlusion. Thus, the implant prosthesis served as a guide for reosteotomized fibula segments. Sagittal split osteotomy was performed on the grafted fibula bone. To improve intraoperative and postoperative occlusal stability, an occlusal splint was also constructed on the model surgery cast. In November 2011, the temporary implant prostheses were connected to implants before surgery. We retained the position of the left RCU by using a condyle positioning plate. A sagittal split osteotomy was performed at the fibula bone located at the mandibular body and angle area. An additional vertical osteotomy on the symphysial area of the fibula-mandibular interface had been performed (Fig. 3B). After repositioning of the temporary prostheses on the dental implants and the free fibula bone by using a surgical splint and intermaxillary fixation screws, proximal RCU was positioned with the condyle positioning plate. The osteotomized fibula bone was fixed with miniplates (Figs. 3C, D). One week after the surgery, the intermaxillary fixation was removed. There was no further movement of the fibula bone postoperatively. Six months after the orthognathic surgery at the fibula, the
1834
FIGURE 2. A, The reconstruction plate had been removed, and 3 dental implants were installed to the previously grafted fibula 14 months after the initial surgery with microsurgical reconstruction. To improve the bilateral asymmetry, the iliac bone was grafted to the inferior border of the left mandibular body area. Compared with preoperative outline (line), the movement of the fibula and the RCU resulted in a flattening of the angle area. B, The fibular segments were osteotomized by using the sagittal split osteotomy, and the fibular-mandibular junction at the symphysis was vertically osteotomized to correct the improper occlusal table position and facial asymmetry. C, Eighteen months after the sagittal splitting of the grafted fibula, there was favorable bony healing without significant RCU movement.
final prostheses were connected after the surgery, and the postoperative stability was favorable.
DISCUSSION Mandibular resection surgeries with remaining large bone defect can be successfully managed by fibula free flap since previous reports from Taylor et al9 and Hidalgo.10 Currently, minimization of the
FIGURE 3. A, A three-dimensional computed tomographic image shows the sagittal split ramus osteotomy bony cutting line on the ramus and the fibula bone and the symphysis cutting line (white line). B, After the orthognathic surgery, the fibula was successfully repositioned, and the asymmetric mandibular shape was improved. C, Immediately before orthognathic surgery, a temporary surgical prosthesis was fabricated to guide the fibula to the optimal position. D, After orthognathic surgery, a favorable occlusal relationship could be achieved.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 5, September 2014
surgical error is directly related to surgical outcomes such as esthetics and functional recovery. Therefore, predicting the length of the fibula, determining the cutting angle before surgery, creating a surgical template for mandibular resection, and preserving mandibular position are more important. We also used the rapid prototype model, which helps to estimate resection margins and reconstruction plates that hold the remaining mandibular position and fibula contour to minimize surgical error and operation time. However, in this case, the left mandibular angle gradually developed into an obtuse angle, and the vertical occlusal dimension decreased a long period after the surgery. The reason for this remarkable positional change of the segments even under the rigid fixation with a reconstruction plate needs explanation. We propose the following possible contributing factors. First, we suspected that decreased bony contact may have affected the bony change. During surgery, the fibula bone was fixed at a lower position than the original position of the mandibular body. Then, the overall height of the ramus was increased, and the bony contact between the fibula and the remaining mandible was decreased. This might be attributed to low bony stability. Second, pulling of the masseteric sling may have resulted in bony changes. Increased vertical height leads to increasing tension of the masseteric sling. We used a reconstruction plate to maintain the mandible and the grafted fibula, and in the follow-up radiographic examination, there was no screw loosening. Therefore, the obtuse change in the mandibular angle likely resulted from the increased pulling of the masseteric sling. In addition, movement of the mandibular angle in the anterior-medio-superior direction, which is the same direction as the masseteric sling action, was observed in the series of panoramic and anterior-posterior plane radiographs. Third, absence of early recovery of occlusal height may have been a factor contributing to bony change. Proper treatment for maintaining vertical occlusal height, such as temporary dentures, early implant insertion, and superior prostheses, was not applied during the early stage. Some reports indicate that immediate functional implant and screw-secured fixed prosthesis serve as an external fixator for the implants and grafted bone.11,12 However, we started occlusal rehabilitation with implant insertion after 14 months. During this period, continuous reduction of the vertical dimension and flattening of the mandibular angle might continue to occur. To circumvent postoperative malocclusion after fibula free flaps, osteotomies onto the reconstruction sites had been reported by Chang et al13 (2003) and Gennaro et al14 (2010). In these previous reports, the junction of the fibula and the native mandibular bone was osteotomized to reposition the fibula.13 The step osteotomy on the fibula free flap was applied to improve sagittal or vertical height defect.14 In our case, fibula segments were osteotomized by using the sagittal split osteotomy, and the fibula-mandibular junction at the symphysis was vertically osteotomized to correct the improper occlusal table position and facial asymmetry. Use of the sagittal split osteotomy for the previously grafted fibula has several advantages. Realignment of grafted segment with vertical13 or step osteotomy14 can result in significant horizontal or vertical interbony gap that can result in unstable final occlusion a long period after surgery. Sagittal split osteotomy can ensure better osseous contact surface between the proximal and the distal bone to allow faster bone healing. Especially, when the grafted segments need to be mobilized buccolingually or need to be rotated from the original position, vertical or step osteotomy onto the long and slender fibula can result in the absence
Orthognathic Surgery at the Fibular Flap
of bony contact. Therefore, sagittal split osteotomy of the fibula including the ramus such as conventional sagittal split ramus osteotomy would be the better option to simplify the surgery, increase bony contact for healing, maximize bony stability after surgery, move the occlusal table of the fibula bone to the proper position, and improve the facial asymmetry. In our case of mandibular reconstruction with a fibula free flap after mandibular resection, the grafted fibula bone and host mandible moved to an unexpected position because of masseteric pulling and a lack of bony stability. This resulted in an improper change of occlusal table for dental implant and aggravation of facial asymmetry. We corrected these problems with a sagittal split osteotomy on the grafted fibula similar to a sagittal split ramus osteotomy for mandibular deformity. The experience of our study highlighted the feasibility of sagittal split of the previously grafted site, and applying the concept of orthognathic surgery would be a successful treatment option for correction of malpositioned graft site by microvasular reconstruction.
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© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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