- Email: [email protected]
Zygomatic Distraction Osteogenesis for Correction of Midfacial Support After Hemimaxillectomy: Experience and Technical Considerations
Zygomatic Distraction Osteogenesis for Correction of Midfacial Support After Hemimaxillectomy: Experience and Technical Considerations Ana Laura Capote-Moreno, MD, PhD,* Luis Naval-Gıas, MD, DMD, PhD,y Mario F. Mu~ noz-Guerra, MD, PhD,z and Francisco J. Rodrıguez-Campo, MDx Purpose: The maxilla is the functional and esthetic keystone of the midface, and large maxillary defects remain a challenge for reconstructive surgery. Different regional and microvascularized flaps have been used to restore the hemimaxilla. Distraction osteogenesis offers an alternative to complex flaps, with less donor-site morbidity. This method is also preferable as a secondary reconstruction in cases of serious bone defects where other flaps have failed. Patients and Methods: Four patients with maxillary defects after oncologic ablation presented at a mean follow-up period of 36 months (standard deviation, 18 mo). In these patients, transport distraction osteogenesis of the zygoma was used to restore the bony support of the low maxilla. Results: After a latency period of 15 days, distraction began at a rate of 0.5 mm/day. A 2-step distraction, by changing the direction of the zygomatic device, was carried out in 3 cases. After a consolidation period of 4 to 6 months for each distraction, the devices were removed and the bone edges were joined together with an autogenous bone graft (anterior iliac crest and calvaria). A good quality of bone was observed in the distracted gap, which allowed for postoperative dental implant placement and prosthetic rehabilitation. Conclusion:
In patients with large maxillary defects in which the remaining bone is insufficient and in patients in whom other reconstructive methods have failed, zygomatic distraction is an excellent option to restore the low projection of the maxilla. Bone transport was found to be a stable reconstructive method that allowed for the restoration of function and esthetics in oncologic patients. Ó 2013 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 71:e189-e197, 2013
The goals of maxillary reconstruction are the isolation of the oral cavity from other facial structures, such as the maxillary sinus, nasal cavity, and orbit, and restoration of the bone skeleton in the midface that allows for good esthetic and function.2 Classically, locoregional and distant flaps have been used for maxillary reconstruction. Several pedicled flaps, such as the temporalis flap and the pectoralis mayor flap, have been used to cover intraoral defects after
The maxilla is the anatomic and functional keystone of the midface. It provides support for several structures, such as as the orbits, the nasal unit, and the zygomaticmalar complex. Oncologic ablation and trauma are the most frequent causes of acquired maxillary defects.1 Reconstruction of these maxillary defects remains a challenge for maxillofacial surgeons because of the complex structure of the maxilla and its anatomic relations. *Staff Surgeon, Department of Oral and Maxillofacial Surgery,
Address correspondence and reprint requests to Dr Capote-
University Hospital La Princesa, Madrid, Spain.
Moreno: Department of Oral and Maxillofacial Surgery, Hospital La
yStaff Surgeon, Department of Oral and Maxillofacial Surgery,
Princesa, Universidad Aut onoma de Madrid, c/ Diego de Le on 62,
University Hospital La Princesa, Madrid, Spain, and Director,
28006 Madrid, Spain; e-mail: [email protected]
Depatment of Oral and Maxillofacial Surgery, Clinica Universidad
Ó 2013 American Association of Oral and Maxillofacial Surgeons
de Navarra, Pamplona, Spain. zStaff Surgeon, Department of Oral and Maxillofacial Surgery,
0278-2391/12/01658-8$36.00/0 http://dx.doi.org/10.1016/j.joms.2012.11.019
University Hospital La Princesa, Madrid, Spain. xStaff Surgeon, Department of Oral and Maxillofacial Surgery, University Hospital La Princesa, Madrid, Spain.
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e190 maxillectomies.3 However, these flaps provide no bone support for the maxilla. With the introduction of microvascularized flaps, such as the fibula, iliac crest, osteofasciocutaneous radial forearm, and scapula, combined osteocutaneous reconstruction became feasible.2,4 These flaps offer adequate amounts of tissue to cover the mucosa and to reconstruct the osseous support of the bone defect, but they require prolonged operating time and training, and risk donor-site morbidity.1 Bone distraction osteogenesis (BDO) offers an excellent alternative for osseous reconstruction of the midface in cases in which other reconstructive methods have failed and in primary cases in which a technique with low morbidity is required.5-7 Patients are selected according to several criteria: bone defects in which other flaps have failed, absence of bone reconstruction with other flaps (delayed reconstruction), a need for a shorter operating time owing to poor general health, and a need for less donor-site morbidity with complex combined flaps such as with microvascularized flaps. Bone transport consists of generating new bone by gradually distracting a transport disc created on the remnant bone. Successful results were first described in mandibular reconstruction.5,6 Rachmiel et al8 were the first to report the feasibility of maxillary distraction in a sheep model. Similarly, Cheung et al9 were the first to reconstruct posterior maxillectomy defects by transport DO in animal models. In hemimaxillectomies, this technique can be used reliably as an alternative to conventional flaps. A bone disc is created in the zygomatic bone and is distracted first in an oblique way and then in a horizontal or vertical direction. These 2 steps restore the vertical height and anterior projection of the maxilla. These 2 distractions also allow for postoperative implant placement and prosthetic rehabilitation in the newly distracted bone. The authors present a series of 4 cases in which DO of the zygomatic bone was used to reconstruct large maxillary defects after oncologic treatment.
Patients and Surgical Technique Four patients (2 men and 2 women; age range, 17 to 71 yr) presented with maxillary defects after oncologic ablation (hemimaxillectomies) at a mean follow-up of 36 months (standard deviation, 18 mo). Transport DO of the zygoma was used to restore the bony support of the lower maxilla in all cases. In 2 cases, primary reconstructive techniques that were attempted had failed or provided insufficient bone. In the other 2 cases, distraction was used as the primary reconstructive method in combination with other flaps. This retrospective study had specific approval from the ethical committee of the authors’ hospital, although it was a report on a series of cases. All patients gave consent for the specific treatment and for the study. Details on gender, age, onco-
ZYGOMATIC DISTRACTION OSTEOGENESIS
logic antecedents, previously attempted reconstructive methods, type of distraction, duration of the latency and consolidation periods, rate of distraction, complications, secondary surgeries after distraction, and functional and esthetic results were recorded (Table 1). A semiburied modular distractor (Modus, Medartis, Basel, Switzerland) was used in all cases. The device had a length of 40 mm in an open position, with 2 titanium miniplates in each edge. The device allowed for the use of interchangeable plates of different sizes and shapes depending on the requirements of the subjacent bone. This allowed for an adaptation of the device to the transport disc and to the remnant bone. The device was placed while the patient was under general anesthesia. This procedure can be carried out during oncologic surgery in cases of primary reconstruction of the maxilla or during secondary surgery in cases of delayed reconstruction. In cases of secondary reconstruction, an incision was made intraorally across the gingival border of the remnant alveolar crest and across the mucosa of the myofascial temporalis flap in cases of intraoral flap reconstruction. The mucoperiosteum flap was elevated until the zygomatic remnant bone was reached. In cases of primary reconstruction, the device was placed on the bone before mucosal flap reconstruction. The bone disc was created on the zygoma with a saw and the distractor was anchored in this disc. At this point in the procedure, distraction could be performed in 1 of 2 ways. 1) The device could be opened and the free end of the device could be attached to the contralateral maxilla with bicortical screws to perform a first-step counterclockwise distraction. 2) The device could start in a closed position with the 2 ends attached to the zygoma, resulting in the distraction of the bone in 2 pieces when the device was activated in a clockwise turn. It was important to preserve the periosteum and muscular attachments of the disc to ensure blood flow to the area. In cases of 2step distraction, the position of the device was changed during a second surgery to modify the vector of distraction. A new bone disc was created in this second distraction. Transport disc mobility was always tested intraoperatively. The device activator was located intraorally when the soft tissues and the mucosa covering allowed it. In other cases, it was placed extraorally. After bone distraction, the devices were removed and free bone grafts were placed between the new bone and the remnant bone when needed. Osteointegrated implants (Mozo-Grau, Valladolid, Spain) were placed on this newly generated bone for dental rehabilitation.
Report of Cases CASE 1
A 34-year-old man was referred to the authors’ department for a 1-year right maxillary mass. It was diagnosed as an osteosarcoma of the maxilla and a right
CAPOTE-MORENO ET AL
Table 1. PATIENTS’ CHARACTERISTICS AND DISTRACTION ISSUES
Age Case Gender (yr)
Oncologic Pathology
1
M
34 osteosarcoma in right maxilla
2
F
17 synovial sarcoma in right maxilla
3
F
46 SCC of palate
4
M
Primary Reconstruction
Distraction Type
Latency Period (wk)/Rate Consolidation (mm/day) Period
free calvarial graft, fibula flap
2-step DIO of right zygoma per stereolithographic model DIO temporalis 2-step DIO of right flap zygoma
temporalis flap 2-step DIO of left zygoma per stereolithographic model unidirectional DIO, first DIO 71 SCC of left open device per temporalis nasal cavitystereolithographic flap premaxilla model
Complications
Secondary Surgeries
2/0.5
4 mo per DIO soft tissue deficiency
2/0.5
4 mo per DIO left hemimaxillary calvarial bone grafts aligned upper deviation, Le Fort I after DIO and OI midline, osteotomy for good esthetic repositioning 4-5 mo per miniplate breakdown calvarial bone graft hybrid prosthesis, DIO of device and OI good esthetic
2/0.5
2/0.5
4-5 mo
iliac crest bone grafts after DIO and OI
Results hybrid prosthesis acceptable, short upper lip
waiting for implant reconstruction delay DIO removal and rehabilitation titanium miniplate owing to secondary placement neoplasms
Abbreviations: DIO, internal distraction osteogenesis; F, female; M, male; OI, osteointegrated implants; SCC, squamous cell carcinoma. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
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e192 hemimaxillectomy was performed. The primary reconstruction consisted of a temporalis flap to cover the mucosal defect and a free calvarial graft for the bone defect. The graft was lost in the first months. Secondary reconstruction with a free fibula flap also failed owing to a venous thrombosis in the immediate postoperative period. The patient received adjuvant postoperative radiotherapy (cumulative doses of 54 Gy). A 2-step BDO was selected for secondary reconstruction. The vector of the first distraction of the zygoma was calculated previously using a stereolithographic model. An intraoral longitudinal incision was made from the alveolar crest of the contralateral premaxilla to the mucosa of the temporalis flap. After elevation of the mucoperiosteal flap, the zygomatic bone was identified and an oblique osteotomy was performed as designed previously on the stereolithographic model. Immediately after bone disc osteotomy, a Modus device (Medartis, Basel, Switzerland) was placed on the right zygoma in a closed position and activated to obliquely distract the bone. The activator of the device was extraorally located in this case. After a latency period of 15 days, distraction began at a rate of 0.5 mm/day. The oblique distraction of the zygomatic disc was performed to reconstruct the vertical height of the maxillary defect. The distracted bone matured during a consolidation period of 4 months, after which the vector of distraction was changed to horizontal. The device position was altered while the patient was under general anesthesia. This second distraction created a new bone disc from previously generated bone. A second distractor was placed on the remnant bone of the left maxilla and horizontally distracted to the right defect. Vertical osteotomies were created with a saw in the 2 sides and the device was placed in a closed position. The latency period and rate of distraction were 15 days and 0.5 mm/day, respectively. The consolidation period was 5 months. After the final consolidation period, the devices were removed and free anterior iliac crest grafts were placed between the newly distracted bones of the 2 distracted sides. A good quality of bone was observed in the distracted gap. Three osteointegrated implants were placed in the distracted bone, with good osseointegration. This allowed for dental rehabilitation with a hybrid dental prosthesis.
ZYGOMATIC DISTRACTION OSTEOGENESIS
FIGURE 1. Case 2. Synovial sarcoma of the right maxilla in a 17year-old woman. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
BDO was selected as the primary reconstructive technique owing to the young age of the patient and to avoid donor-site morbidity, which is common with major flap reconstruction. The device was placed during the same surgery for tumor ablation (Fig 2). After oncologic resection, a transport disc was created with an oblique osteotomy of the right zygoma using a saw. The distractor was fixed obliquely in an open position, with 1 edge placed on the zygomatic disc with bicortical screws and the other edge on the remnant left premaxilla. Mobility of the disc transport was proved intraoperatively. Afterward, the mucosal defect was covered with a right myofascial temporalis flap. The activator of the device was left on intraorally. After a 15-day latency period, the distractor was activated in
CASE 2
A 17-year-old woman presented with a radiolucent lesion in her right maxilla that was clinically diagnosed as an odontogenic cyst. During the first surgery, the authors observed an expanded solid lesion in the premolar region that had eroded the maxillary sinus floor bone (Fig 1). The final histopathologic examination of the sample showed it to be a synovial sarcoma; as a result, a right hemimaxillectomy was planned for oncologic purposes.
FIGURE 2. Case 2. Primary internal distraction osteogenesis after right hemimaxillectomy. The device was placed on the right zygoma and the mucosal defect was reconstructed with a temporalis myofascial flap. The activator was placed intraorally. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
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FIGURE 3. Case 2. Panoramic view of the device during the first step of oblique distraction. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
a counterclockwise direction at a rate of 0.5 mm/day (Figs 3, 4). During the 4-month consolidation period, the authors observed a deviation of the left residual maxilla toward the right-side defect, which needed a Le Fort I osteotomy to center the upper midline. Le Fort osteotomy was performed at the same time as the second distraction. With the patient under general anesthesia, a longitudinal incision across the mucosa of the temporalis flap was made. The newly generated bone and the device were isolated. The device was taken off and a horizontal osteotomy was created on this bone to generate a new disc. A second distractor was placed on the newly generated bone to distract it in a vertical direction to gain alveolar bone (Fig 5). Mobility of the disc was confirmed intraoperatively. The latency period and rate of distraction were 15
FIGURE 5. Case 2. Second step of vertical distraction in a panoramic view after the activation period. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
days and 0.5 mm/day, respectively. After a final consolidation period, the device was removed and free calvarial grafts were placed between the newly distracted bone edge and the remnant bone (Fig 6). This allowed for final dental implant rehabilitation with 3 osteointegrated implants. The right central upper incisor was preserved. The implant near the midline was distally placed to avoid a small defect observed in the junction between the distracted bone and the left premaxilla (Fig 7). All implants had good osseointegration after 6 months and the patient was rehabilitated with a right-side hybrid prosthesis (Fig 8). The facial esthetic was satisfactory after the reconstructive technique. CASE 3
A 46-year-old woman was referred to the authors’ department with oncologic sequelae after a left
FIGURE 4. Case 2. Three-dimensional view of disc transport and new generated bone after the activation period during the first step of distraction.
FIGURE 6. Case 2. Axial computed tomogram of final distraction with newly generated bone and final maxillary reconstruction with calvarial grafts.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
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FIGURE 9. Case 3. Initial panoramic view of left-side defect after hemimaxillectomy. FIGURE 7. Case 2. Final implant placement in newly distracted bone. The implant within the midline was placed obliquely in the distracted bone to avoid the junction gap to the left hemimaxilla. All implants were successfully osteointegrated after 6 months. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
hemimaxillectomy for squamous cell carcinoma of the palate that had been resected in another hospital and primarily reconstructed with a temporalis myofascial flap (Table 1). Unfortunately, the reconstructed maxilla has no bone support and poor esthetics (Fig 9). BDO was selected as an alternative to microvascularized flaps because of less donor-site morbidity. A semiburied distractor device was placed in the left zygoma while the patient was under general anesthesia. The transport disc was designed previously in a stereolithographic model (Fig 10). An incision was created across the mucosa of the temporalis flap and the zygomatic bone was reached after mucoperiosteum flap detachment. An oblique osteotomy was performed in the zygoma with a saw to create the disc. In this case, an oblique vector was chosen for the first distraction, with the device starting in an open position while
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
attached to the bone disc and to the remnant bone (Figs 11, 12). The activator of the device was left on intraorally. The latency period was 15 days and the rate of distraction was 0.5 mm/day. After 4 months, the same distractor was replaced owing to a miniplate breakdown by using an oblique vector and refracturing the distracted bone. When this second distraction moved left, the defect had finally closed (Fig 13). After 5 months, the device was removed and a calvarial free graft was used to join the new bone and the right hemimaxilla. A good quality of bone was observed in the distracted gap. Three osteointegrated implants were placed in the distracted bone to allow for a hybrid prosthesis, with good functional and stable results (Figs 14 through 17). CASE 4
A 71-year-old man presented with squamous cell carcinoma of the left nasal cavity and premaxilla. During the first surgery, the patient was treated in the authors’ department with a radical local resection of the
FIGURE 8. Case 2. Intraoral final esthetics after distraction procedure and implant rehabilitation with right-side hybrid prosthesis.
FIGURE 10. Case 3. Stereolithographic model with device placement planed on the zygoma and the design of bone transport.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
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FIGURE 11. Case 3. Panoramic view of device placement on the left zygoma. The bone disc is distracted to the contralateral right remnant bone.
FIGURE 13. Case 3. Second step of distraction during activation period. In this case, the device was placed obliquely to distract the bone to the midline.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
tumor, a cervical dissection, and a myofascial temporalis flap to cover the mucosal defect. The patient underwent radiation in the postoperative period with a cumulative dose of 50 Gy. BDO was the technique selected for bone reconstruction owing to the patient’s advanced age and poor general medical status, which eliminated the use of an aggressive reconstructive method such as a microvascularized flap. In this case, a unidirectional distraction was selected. A longitudinal incision across the reconstructed mucosa of the temporalis flap was made and the left zygoma was localized. After an oblique osteotomy and disc creation, the device was placed between the left zygoma and the remnant maxilla in an open position to distract the disc in an oblique manner. The device
placement was tested previously in the stereolithographic model. However, this primary BDO reconstruction was impeded by the need to remove a pulmonary adenocarcinoma. After the lung mass was removed and the patient fully recovered, distraction of the zygoma was started. The transport disc was then refractured and the device was replaced as previously planned. The activator was placed intraorally. The latency period and activation rate were 15 days and 0.5 mm/day, respectively. After a consolidation period of 4.5 months, the bone edges were joined together with a titanium miniplate. No bone graft was needed in this case. The case is pending for implant rehabilitation because of recurrence of the pulmonary tumor.
Discussion BDO has been a revolutionary technique in reconstructive surgery in the past decade and has offered an alternative to conventional reconstructive methods in the maxillofacial area because it requires a shorter operating time and produces less morbidity.5,6 DO has been described as a secondary procedure when
FIGURE 12. Case 3. Three-dimensional view of newly generated bone during the consolidation period at the end of the first step of distraction. In this case, the closed position of the device indicated the end of disc distraction.
FIGURE 14. Case 3. Osteointegrated implants placed on newly generated bone after distraction.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
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FIGURE 17. Case 3. Final panoramic view with hybrid prosthesis. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
FIGURE 15. Case 3. Intraoral view of oral implants. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
other flaps have failed. However, several recent studies have reported good functional and esthetic results with BDO in primary reconstruction after tumor Moreover, with this techablation.1,7,10,11 nique, the need for additional grafts is much less than without DO.7 In the present study, these 4 patients had distinct medical histories and physical characteristics. Two patients had previously undergone alternative reconstructive surgeries that had failed to provide bone support, and the other 2 patients were undergoing primary reconstruction of the bone defect with BDO. As described earlier, the criteria for the selection of distraction as the reconstructive technique are bone defects in which other flaps have failed, absence of bone reconstruction with these flaps (delayed reconstruction), a need for a shorter operating time owing to poor general health, and a need for less donor-site morbidity, such as in young patients
FIGURE 16. Case 3. Final intraoral rehabilitation. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
or patients with other medical pathologies. Therefore, the main advantages of BDO are the low morbidity of the technique and a shorter operating time. However, this technique requires at least 2 surgeries, especially in 2-step distraction. Also, the time of consolidation that is required by the bone after the activation period is lengthened in oncologic and radiated patients. DO also influences the soft tissues.12 As bone is distracted, the mucoperiosteum and soft tissue are expanded. This mucoperiosteum provides good blood supply to the new bone and regenerates the attached gingival mucosa at the alveolar process. Having a better quality of soft tissues surrounding the distraction site improves the dental implant success rate more than by having the implants placed in other bone flaps, such as microvascularized free flaps in which soft tissue is often too thick.1,7,12,13 Constantino et al14 reported that the diameter of newly generated bone was similar to the diameter of the disc transport and of the residual mandible. The authors observed macroscopically a good quality of the new bone after the consolidation period in all cases in this series. This allowed endosseous dental implant rehabilitation after distraction to restore masticatory function. In maxillary resections, large mucosal defects associated with bone resection are commonly observed. In 2 of the present cases, BDO was the method of choice after tumor resection. Device placement was performed during the same surgery as the hemimaxillectomy. However, the mucosal defect had to be covered with associated flaps, with the temporalis myofascial flap being the most frequently used in this series. This avoided exposition of the device to the oral cavity and allowed for a better quality of life for the patient during the distraction period. In addition, although the temporalis flap undergoes metaplasia, one can observe with bone transport an improvement of the soft tissue quality surrounding the distracted bone. Another issue is late versus immediate reconstruction after tumor ablation. With late reconstruction, as occurred in case 3, the immediate
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complications of tumor disease and early relapse are avoided. A patient’s better general status is preferable to obtain better results with bone reconstruction. Conversely, with immediate reconstruction, the esthetics and maxillary function are restored relatively quickly.7 This may be of importance in young patients, as in case 2, and in those patients in whom other adjuvant therapies are not foreseeable. In large maxillary defects after hemimaxillectomy, zygomatic distraction is a feasible method for reconstruction of the lower maxilla. Some case reports have described the technique of distraction of a bone disc transport of the remnant zygoma.1,11,15 The authors have presented a series of 4 cases in which zygomatic disc transport was used to reconstruct the hemimaxilla. This method generally requires a 2-step distraction to reconstruct the maxilla tridimensionally.5,12 In zygomatic distraction, the bone disc is distracted first in an oblique direction to gain height. Then, the bone can be distracted in a horizontal or vertical direction across the gap to restore the alveolar process. This distraction protocol also facilitates a better control of the vectors of distraction, although it increases the reconstruction time.7 Niu et al11 also distracted a segment of the hard palate to the midline for transversal reconstruction associated with a curvilinear device to reconstruct the alveolar ridge. The authors obtained good results with 2-step distraction in 3 patients; in the other patient, a unidirectional distraction was enough to reconstruct the defect. Latency periods in the literature have ranged from 5 to 15 days.1,11,15 Activation rates generally have ranged from 1 to 0.5 mm/day. The authors prefer a latency period of 15 days and a rate of 0.5 mm/day in patients with oncologic treatment to prevent wound dehiscence and ensure a blood supply to the disc during distraction. A slower rate of bone transport might have the risk of premature consolidation of the disc. Another reason for a slow rate of distraction is that oncologic patients frequently undergo irradiation postoperatively. In these cases, the authors prefer to take the transport disc as far as possible from the maximal radiation area. BDO has shown good results in irradiated patients, although radiation decreases hard and soft tissue vasculatures.3,7,10 In this series, 2 patients received postoperative radiotherapy, but developed no complications from BDO. One patient also had successful dental implant placement. One disadvantage of BDO is time. Although this method decreases the surgical time of device placement, the entire reconstruction time is longer.11,15 These oncologic patients need some surgical interventions and a longer consolidation period. It is frequently necessary to use small bone grafts to join
together the distracted bone and the distal stump (iliac crest and calvaria). Possible complications of the procedure include discomfort (most frequent in intraoral devices), intra- or extraoral exposure of the device, premature consolidation, device breakdown, and implant failure.7 In 1 case, the authors observed a deviation of the contralateral maxilla to the bone defect because of soft tissue forces during the distraction period. This was solved by Le Fort I osteotomy to reposition the maxilla. In conclusion, BDO offers an excellent alternative to conventional techniques in maxillary defects with low morbidity. Zygomatic distraction is a feasible method in hemimaxillectomy defects, which restores lower maxilla projection and allows for dental implant rehabilitation.
References 1. Neelakandan RS, Mathew PC: Intraoral maxillary transport distraction: A case report. J Oral Maxillofac Surg 67:1751, 2009 2. Triana RJ, Uglesic V, Virag M, et al: Microvascular free flap reconstructive options in patients with partial and total hemimaxillectomy defects. Arch Facial Plast Surg 2:91, 2000 3. Dallan I, Lenzi R, Sellari-Franceschini S, et al: Temporalis myofascial flap in maxillary reconstruction: Anatomical study and clinical application. J Craniomaxillofac Surg 37:96, 2009 4. Santamaria E, Cordeiro PG: Reconstruction of maxillectomy and midfacial defects with free tissue transfer. J Surg Oncol 94:522, 2006 5. Snyder CC, Levine GA, Swanson HM, et al: Mandibular lengthening by gradual distraction: Preliminary report. Plast Reconst Surg 51:506, 1973 6. Rubio-Bueno P, Naval L, Rodriguez-Campo F, et al: Internal distraction osteogenesis with unidirectional device for reconstruction of mandibular segmental defects. J Oral Maxillofac Surg 63: 598, 2005 7. Gonzalez-Garcıa R, Naval-Gıas L: Transport osteogenesis in the maxillofacial skeleton. Arch Otolaryngol Head Neck Surg 136: 243, 2010 8. Rachmiel A, Potparic Z, Jackson IT, et al: Midface advancement by gradual distraction. Br J Plast Surg 46:201, 1993 9. Cheung LK, Zhang Q, Zhang ZG, et al: Reconstruction of maxillectomy defect by transport distraction osteogenesis. Int J Oral Maxillofac Surg 32:515, 2003 10. Kashiwa K, Kobayashi S, Kimura H, et al: Reconstruction of a severe maxillofacial deformity after tumorectomy and irradiation using distraction osteogenesis and Le Fort I osteotomy before vascularized bone graft. J Craniofac Surg 18:1133, 2007 11. Niu WG, Zao YM, Han XX: Multiplanar and combined distraction osteogenesis for three-dimensional and functional reconstruction of unilateral large maxillary defects. Br J Oral Maxillofac Surg 47:106, 2009 12. Block MS, Baughman DG: Reconstruction of severe anterior maxilla defects using distraction osteogenesis, bone grafts, and implants. J Oral Maxillofac Surg 63:291, 2005 13. Cheung LK, Zhang Q: Healing of maxillary alveolus in transport distraction osteogenesis for partial maxillectomy. J Oral Maxillofac Surg 62:66, 2004 14. Constantino PD, Shybut G, Friedman CD, et al: Segmental mandibular regeneration by distraction osteogenesis: An experimental study. Arch Otolaryngol Head Neck Surg 116:535, 1990 15. Fujioka M, Kanno T, Mitsugi M, et al: Oral rehabilitation of a maxillectomy defect using bone transport distraction and dental implants. J Oral Maxillofac Surg 68:2278, 2010
In patients with large maxillary defects in which the remaining bone is insufficient and in patients in whom other reconstructive methods have failed, zygomatic distraction is an excellent option to restore the low projection of the maxilla. Bone transport was found to be a stable reconstructive method that allowed for the restoration of function and esthetics in oncologic patients. Ó 2013 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 71:e189-e197, 2013
The goals of maxillary reconstruction are the isolation of the oral cavity from other facial structures, such as the maxillary sinus, nasal cavity, and orbit, and restoration of the bone skeleton in the midface that allows for good esthetic and function.2 Classically, locoregional and distant flaps have been used for maxillary reconstruction. Several pedicled flaps, such as the temporalis flap and the pectoralis mayor flap, have been used to cover intraoral defects after
The maxilla is the anatomic and functional keystone of the midface. It provides support for several structures, such as as the orbits, the nasal unit, and the zygomaticmalar complex. Oncologic ablation and trauma are the most frequent causes of acquired maxillary defects.1 Reconstruction of these maxillary defects remains a challenge for maxillofacial surgeons because of the complex structure of the maxilla and its anatomic relations. *Staff Surgeon, Department of Oral and Maxillofacial Surgery,
Address correspondence and reprint requests to Dr Capote-
University Hospital La Princesa, Madrid, Spain.
Moreno: Department of Oral and Maxillofacial Surgery, Hospital La
yStaff Surgeon, Department of Oral and Maxillofacial Surgery,
Princesa, Universidad Aut onoma de Madrid, c/ Diego de Le on 62,
University Hospital La Princesa, Madrid, Spain, and Director,
28006 Madrid, Spain; e-mail: [email protected]
Depatment of Oral and Maxillofacial Surgery, Clinica Universidad
Ó 2013 American Association of Oral and Maxillofacial Surgeons
de Navarra, Pamplona, Spain. zStaff Surgeon, Department of Oral and Maxillofacial Surgery,
0278-2391/12/01658-8$36.00/0 http://dx.doi.org/10.1016/j.joms.2012.11.019
University Hospital La Princesa, Madrid, Spain. xStaff Surgeon, Department of Oral and Maxillofacial Surgery, University Hospital La Princesa, Madrid, Spain.
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e190 maxillectomies.3 However, these flaps provide no bone support for the maxilla. With the introduction of microvascularized flaps, such as the fibula, iliac crest, osteofasciocutaneous radial forearm, and scapula, combined osteocutaneous reconstruction became feasible.2,4 These flaps offer adequate amounts of tissue to cover the mucosa and to reconstruct the osseous support of the bone defect, but they require prolonged operating time and training, and risk donor-site morbidity.1 Bone distraction osteogenesis (BDO) offers an excellent alternative for osseous reconstruction of the midface in cases in which other reconstructive methods have failed and in primary cases in which a technique with low morbidity is required.5-7 Patients are selected according to several criteria: bone defects in which other flaps have failed, absence of bone reconstruction with other flaps (delayed reconstruction), a need for a shorter operating time owing to poor general health, and a need for less donor-site morbidity with complex combined flaps such as with microvascularized flaps. Bone transport consists of generating new bone by gradually distracting a transport disc created on the remnant bone. Successful results were first described in mandibular reconstruction.5,6 Rachmiel et al8 were the first to report the feasibility of maxillary distraction in a sheep model. Similarly, Cheung et al9 were the first to reconstruct posterior maxillectomy defects by transport DO in animal models. In hemimaxillectomies, this technique can be used reliably as an alternative to conventional flaps. A bone disc is created in the zygomatic bone and is distracted first in an oblique way and then in a horizontal or vertical direction. These 2 steps restore the vertical height and anterior projection of the maxilla. These 2 distractions also allow for postoperative implant placement and prosthetic rehabilitation in the newly distracted bone. The authors present a series of 4 cases in which DO of the zygomatic bone was used to reconstruct large maxillary defects after oncologic treatment.
Patients and Surgical Technique Four patients (2 men and 2 women; age range, 17 to 71 yr) presented with maxillary defects after oncologic ablation (hemimaxillectomies) at a mean follow-up of 36 months (standard deviation, 18 mo). Transport DO of the zygoma was used to restore the bony support of the lower maxilla in all cases. In 2 cases, primary reconstructive techniques that were attempted had failed or provided insufficient bone. In the other 2 cases, distraction was used as the primary reconstructive method in combination with other flaps. This retrospective study had specific approval from the ethical committee of the authors’ hospital, although it was a report on a series of cases. All patients gave consent for the specific treatment and for the study. Details on gender, age, onco-
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logic antecedents, previously attempted reconstructive methods, type of distraction, duration of the latency and consolidation periods, rate of distraction, complications, secondary surgeries after distraction, and functional and esthetic results were recorded (Table 1). A semiburied modular distractor (Modus, Medartis, Basel, Switzerland) was used in all cases. The device had a length of 40 mm in an open position, with 2 titanium miniplates in each edge. The device allowed for the use of interchangeable plates of different sizes and shapes depending on the requirements of the subjacent bone. This allowed for an adaptation of the device to the transport disc and to the remnant bone. The device was placed while the patient was under general anesthesia. This procedure can be carried out during oncologic surgery in cases of primary reconstruction of the maxilla or during secondary surgery in cases of delayed reconstruction. In cases of secondary reconstruction, an incision was made intraorally across the gingival border of the remnant alveolar crest and across the mucosa of the myofascial temporalis flap in cases of intraoral flap reconstruction. The mucoperiosteum flap was elevated until the zygomatic remnant bone was reached. In cases of primary reconstruction, the device was placed on the bone before mucosal flap reconstruction. The bone disc was created on the zygoma with a saw and the distractor was anchored in this disc. At this point in the procedure, distraction could be performed in 1 of 2 ways. 1) The device could be opened and the free end of the device could be attached to the contralateral maxilla with bicortical screws to perform a first-step counterclockwise distraction. 2) The device could start in a closed position with the 2 ends attached to the zygoma, resulting in the distraction of the bone in 2 pieces when the device was activated in a clockwise turn. It was important to preserve the periosteum and muscular attachments of the disc to ensure blood flow to the area. In cases of 2step distraction, the position of the device was changed during a second surgery to modify the vector of distraction. A new bone disc was created in this second distraction. Transport disc mobility was always tested intraoperatively. The device activator was located intraorally when the soft tissues and the mucosa covering allowed it. In other cases, it was placed extraorally. After bone distraction, the devices were removed and free bone grafts were placed between the new bone and the remnant bone when needed. Osteointegrated implants (Mozo-Grau, Valladolid, Spain) were placed on this newly generated bone for dental rehabilitation.
Report of Cases CASE 1
A 34-year-old man was referred to the authors’ department for a 1-year right maxillary mass. It was diagnosed as an osteosarcoma of the maxilla and a right
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Table 1. PATIENTS’ CHARACTERISTICS AND DISTRACTION ISSUES
Age Case Gender (yr)
Oncologic Pathology
1
M
34 osteosarcoma in right maxilla
2
F
17 synovial sarcoma in right maxilla
3
F
46 SCC of palate
4
M
Primary Reconstruction
Distraction Type
Latency Period (wk)/Rate Consolidation (mm/day) Period
free calvarial graft, fibula flap
2-step DIO of right zygoma per stereolithographic model DIO temporalis 2-step DIO of right flap zygoma
temporalis flap 2-step DIO of left zygoma per stereolithographic model unidirectional DIO, first DIO 71 SCC of left open device per temporalis nasal cavitystereolithographic flap premaxilla model
Complications
Secondary Surgeries
2/0.5
4 mo per DIO soft tissue deficiency
2/0.5
4 mo per DIO left hemimaxillary calvarial bone grafts aligned upper deviation, Le Fort I after DIO and OI midline, osteotomy for good esthetic repositioning 4-5 mo per miniplate breakdown calvarial bone graft hybrid prosthesis, DIO of device and OI good esthetic
2/0.5
2/0.5
4-5 mo
iliac crest bone grafts after DIO and OI
Results hybrid prosthesis acceptable, short upper lip
waiting for implant reconstruction delay DIO removal and rehabilitation titanium miniplate owing to secondary placement neoplasms
Abbreviations: DIO, internal distraction osteogenesis; F, female; M, male; OI, osteointegrated implants; SCC, squamous cell carcinoma. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
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e192 hemimaxillectomy was performed. The primary reconstruction consisted of a temporalis flap to cover the mucosal defect and a free calvarial graft for the bone defect. The graft was lost in the first months. Secondary reconstruction with a free fibula flap also failed owing to a venous thrombosis in the immediate postoperative period. The patient received adjuvant postoperative radiotherapy (cumulative doses of 54 Gy). A 2-step BDO was selected for secondary reconstruction. The vector of the first distraction of the zygoma was calculated previously using a stereolithographic model. An intraoral longitudinal incision was made from the alveolar crest of the contralateral premaxilla to the mucosa of the temporalis flap. After elevation of the mucoperiosteal flap, the zygomatic bone was identified and an oblique osteotomy was performed as designed previously on the stereolithographic model. Immediately after bone disc osteotomy, a Modus device (Medartis, Basel, Switzerland) was placed on the right zygoma in a closed position and activated to obliquely distract the bone. The activator of the device was extraorally located in this case. After a latency period of 15 days, distraction began at a rate of 0.5 mm/day. The oblique distraction of the zygomatic disc was performed to reconstruct the vertical height of the maxillary defect. The distracted bone matured during a consolidation period of 4 months, after which the vector of distraction was changed to horizontal. The device position was altered while the patient was under general anesthesia. This second distraction created a new bone disc from previously generated bone. A second distractor was placed on the remnant bone of the left maxilla and horizontally distracted to the right defect. Vertical osteotomies were created with a saw in the 2 sides and the device was placed in a closed position. The latency period and rate of distraction were 15 days and 0.5 mm/day, respectively. The consolidation period was 5 months. After the final consolidation period, the devices were removed and free anterior iliac crest grafts were placed between the newly distracted bones of the 2 distracted sides. A good quality of bone was observed in the distracted gap. Three osteointegrated implants were placed in the distracted bone, with good osseointegration. This allowed for dental rehabilitation with a hybrid dental prosthesis.
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FIGURE 1. Case 2. Synovial sarcoma of the right maxilla in a 17year-old woman. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
BDO was selected as the primary reconstructive technique owing to the young age of the patient and to avoid donor-site morbidity, which is common with major flap reconstruction. The device was placed during the same surgery for tumor ablation (Fig 2). After oncologic resection, a transport disc was created with an oblique osteotomy of the right zygoma using a saw. The distractor was fixed obliquely in an open position, with 1 edge placed on the zygomatic disc with bicortical screws and the other edge on the remnant left premaxilla. Mobility of the disc transport was proved intraoperatively. Afterward, the mucosal defect was covered with a right myofascial temporalis flap. The activator of the device was left on intraorally. After a 15-day latency period, the distractor was activated in
CASE 2
A 17-year-old woman presented with a radiolucent lesion in her right maxilla that was clinically diagnosed as an odontogenic cyst. During the first surgery, the authors observed an expanded solid lesion in the premolar region that had eroded the maxillary sinus floor bone (Fig 1). The final histopathologic examination of the sample showed it to be a synovial sarcoma; as a result, a right hemimaxillectomy was planned for oncologic purposes.
FIGURE 2. Case 2. Primary internal distraction osteogenesis after right hemimaxillectomy. The device was placed on the right zygoma and the mucosal defect was reconstructed with a temporalis myofascial flap. The activator was placed intraorally. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
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FIGURE 3. Case 2. Panoramic view of the device during the first step of oblique distraction. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
a counterclockwise direction at a rate of 0.5 mm/day (Figs 3, 4). During the 4-month consolidation period, the authors observed a deviation of the left residual maxilla toward the right-side defect, which needed a Le Fort I osteotomy to center the upper midline. Le Fort osteotomy was performed at the same time as the second distraction. With the patient under general anesthesia, a longitudinal incision across the mucosa of the temporalis flap was made. The newly generated bone and the device were isolated. The device was taken off and a horizontal osteotomy was created on this bone to generate a new disc. A second distractor was placed on the newly generated bone to distract it in a vertical direction to gain alveolar bone (Fig 5). Mobility of the disc was confirmed intraoperatively. The latency period and rate of distraction were 15
FIGURE 5. Case 2. Second step of vertical distraction in a panoramic view after the activation period. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
days and 0.5 mm/day, respectively. After a final consolidation period, the device was removed and free calvarial grafts were placed between the newly distracted bone edge and the remnant bone (Fig 6). This allowed for final dental implant rehabilitation with 3 osteointegrated implants. The right central upper incisor was preserved. The implant near the midline was distally placed to avoid a small defect observed in the junction between the distracted bone and the left premaxilla (Fig 7). All implants had good osseointegration after 6 months and the patient was rehabilitated with a right-side hybrid prosthesis (Fig 8). The facial esthetic was satisfactory after the reconstructive technique. CASE 3
A 46-year-old woman was referred to the authors’ department with oncologic sequelae after a left
FIGURE 4. Case 2. Three-dimensional view of disc transport and new generated bone after the activation period during the first step of distraction.
FIGURE 6. Case 2. Axial computed tomogram of final distraction with newly generated bone and final maxillary reconstruction with calvarial grafts.
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FIGURE 9. Case 3. Initial panoramic view of left-side defect after hemimaxillectomy. FIGURE 7. Case 2. Final implant placement in newly distracted bone. The implant within the midline was placed obliquely in the distracted bone to avoid the junction gap to the left hemimaxilla. All implants were successfully osteointegrated after 6 months. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
hemimaxillectomy for squamous cell carcinoma of the palate that had been resected in another hospital and primarily reconstructed with a temporalis myofascial flap (Table 1). Unfortunately, the reconstructed maxilla has no bone support and poor esthetics (Fig 9). BDO was selected as an alternative to microvascularized flaps because of less donor-site morbidity. A semiburied distractor device was placed in the left zygoma while the patient was under general anesthesia. The transport disc was designed previously in a stereolithographic model (Fig 10). An incision was created across the mucosa of the temporalis flap and the zygomatic bone was reached after mucoperiosteum flap detachment. An oblique osteotomy was performed in the zygoma with a saw to create the disc. In this case, an oblique vector was chosen for the first distraction, with the device starting in an open position while
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
attached to the bone disc and to the remnant bone (Figs 11, 12). The activator of the device was left on intraorally. The latency period was 15 days and the rate of distraction was 0.5 mm/day. After 4 months, the same distractor was replaced owing to a miniplate breakdown by using an oblique vector and refracturing the distracted bone. When this second distraction moved left, the defect had finally closed (Fig 13). After 5 months, the device was removed and a calvarial free graft was used to join the new bone and the right hemimaxilla. A good quality of bone was observed in the distracted gap. Three osteointegrated implants were placed in the distracted bone to allow for a hybrid prosthesis, with good functional and stable results (Figs 14 through 17). CASE 4
A 71-year-old man presented with squamous cell carcinoma of the left nasal cavity and premaxilla. During the first surgery, the patient was treated in the authors’ department with a radical local resection of the
FIGURE 8. Case 2. Intraoral final esthetics after distraction procedure and implant rehabilitation with right-side hybrid prosthesis.
FIGURE 10. Case 3. Stereolithographic model with device placement planed on the zygoma and the design of bone transport.
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FIGURE 11. Case 3. Panoramic view of device placement on the left zygoma. The bone disc is distracted to the contralateral right remnant bone.
FIGURE 13. Case 3. Second step of distraction during activation period. In this case, the device was placed obliquely to distract the bone to the midline.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
tumor, a cervical dissection, and a myofascial temporalis flap to cover the mucosal defect. The patient underwent radiation in the postoperative period with a cumulative dose of 50 Gy. BDO was the technique selected for bone reconstruction owing to the patient’s advanced age and poor general medical status, which eliminated the use of an aggressive reconstructive method such as a microvascularized flap. In this case, a unidirectional distraction was selected. A longitudinal incision across the reconstructed mucosa of the temporalis flap was made and the left zygoma was localized. After an oblique osteotomy and disc creation, the device was placed between the left zygoma and the remnant maxilla in an open position to distract the disc in an oblique manner. The device
placement was tested previously in the stereolithographic model. However, this primary BDO reconstruction was impeded by the need to remove a pulmonary adenocarcinoma. After the lung mass was removed and the patient fully recovered, distraction of the zygoma was started. The transport disc was then refractured and the device was replaced as previously planned. The activator was placed intraorally. The latency period and activation rate were 15 days and 0.5 mm/day, respectively. After a consolidation period of 4.5 months, the bone edges were joined together with a titanium miniplate. No bone graft was needed in this case. The case is pending for implant rehabilitation because of recurrence of the pulmonary tumor.
Discussion BDO has been a revolutionary technique in reconstructive surgery in the past decade and has offered an alternative to conventional reconstructive methods in the maxillofacial area because it requires a shorter operating time and produces less morbidity.5,6 DO has been described as a secondary procedure when
FIGURE 12. Case 3. Three-dimensional view of newly generated bone during the consolidation period at the end of the first step of distraction. In this case, the closed position of the device indicated the end of disc distraction.
FIGURE 14. Case 3. Osteointegrated implants placed on newly generated bone after distraction.
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FIGURE 17. Case 3. Final panoramic view with hybrid prosthesis. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
FIGURE 15. Case 3. Intraoral view of oral implants. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
other flaps have failed. However, several recent studies have reported good functional and esthetic results with BDO in primary reconstruction after tumor Moreover, with this techablation.1,7,10,11 nique, the need for additional grafts is much less than without DO.7 In the present study, these 4 patients had distinct medical histories and physical characteristics. Two patients had previously undergone alternative reconstructive surgeries that had failed to provide bone support, and the other 2 patients were undergoing primary reconstruction of the bone defect with BDO. As described earlier, the criteria for the selection of distraction as the reconstructive technique are bone defects in which other flaps have failed, absence of bone reconstruction with these flaps (delayed reconstruction), a need for a shorter operating time owing to poor general health, and a need for less donor-site morbidity, such as in young patients
FIGURE 16. Case 3. Final intraoral rehabilitation. Capote-Moreno et al. Zygomatic Distraction Osteogenesis. J Oral Maxillofac Surg 2013.
or patients with other medical pathologies. Therefore, the main advantages of BDO are the low morbidity of the technique and a shorter operating time. However, this technique requires at least 2 surgeries, especially in 2-step distraction. Also, the time of consolidation that is required by the bone after the activation period is lengthened in oncologic and radiated patients. DO also influences the soft tissues.12 As bone is distracted, the mucoperiosteum and soft tissue are expanded. This mucoperiosteum provides good blood supply to the new bone and regenerates the attached gingival mucosa at the alveolar process. Having a better quality of soft tissues surrounding the distraction site improves the dental implant success rate more than by having the implants placed in other bone flaps, such as microvascularized free flaps in which soft tissue is often too thick.1,7,12,13 Constantino et al14 reported that the diameter of newly generated bone was similar to the diameter of the disc transport and of the residual mandible. The authors observed macroscopically a good quality of the new bone after the consolidation period in all cases in this series. This allowed endosseous dental implant rehabilitation after distraction to restore masticatory function. In maxillary resections, large mucosal defects associated with bone resection are commonly observed. In 2 of the present cases, BDO was the method of choice after tumor resection. Device placement was performed during the same surgery as the hemimaxillectomy. However, the mucosal defect had to be covered with associated flaps, with the temporalis myofascial flap being the most frequently used in this series. This avoided exposition of the device to the oral cavity and allowed for a better quality of life for the patient during the distraction period. In addition, although the temporalis flap undergoes metaplasia, one can observe with bone transport an improvement of the soft tissue quality surrounding the distracted bone. Another issue is late versus immediate reconstruction after tumor ablation. With late reconstruction, as occurred in case 3, the immediate
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complications of tumor disease and early relapse are avoided. A patient’s better general status is preferable to obtain better results with bone reconstruction. Conversely, with immediate reconstruction, the esthetics and maxillary function are restored relatively quickly.7 This may be of importance in young patients, as in case 2, and in those patients in whom other adjuvant therapies are not foreseeable. In large maxillary defects after hemimaxillectomy, zygomatic distraction is a feasible method for reconstruction of the lower maxilla. Some case reports have described the technique of distraction of a bone disc transport of the remnant zygoma.1,11,15 The authors have presented a series of 4 cases in which zygomatic disc transport was used to reconstruct the hemimaxilla. This method generally requires a 2-step distraction to reconstruct the maxilla tridimensionally.5,12 In zygomatic distraction, the bone disc is distracted first in an oblique direction to gain height. Then, the bone can be distracted in a horizontal or vertical direction across the gap to restore the alveolar process. This distraction protocol also facilitates a better control of the vectors of distraction, although it increases the reconstruction time.7 Niu et al11 also distracted a segment of the hard palate to the midline for transversal reconstruction associated with a curvilinear device to reconstruct the alveolar ridge. The authors obtained good results with 2-step distraction in 3 patients; in the other patient, a unidirectional distraction was enough to reconstruct the defect. Latency periods in the literature have ranged from 5 to 15 days.1,11,15 Activation rates generally have ranged from 1 to 0.5 mm/day. The authors prefer a latency period of 15 days and a rate of 0.5 mm/day in patients with oncologic treatment to prevent wound dehiscence and ensure a blood supply to the disc during distraction. A slower rate of bone transport might have the risk of premature consolidation of the disc. Another reason for a slow rate of distraction is that oncologic patients frequently undergo irradiation postoperatively. In these cases, the authors prefer to take the transport disc as far as possible from the maximal radiation area. BDO has shown good results in irradiated patients, although radiation decreases hard and soft tissue vasculatures.3,7,10 In this series, 2 patients received postoperative radiotherapy, but developed no complications from BDO. One patient also had successful dental implant placement. One disadvantage of BDO is time. Although this method decreases the surgical time of device placement, the entire reconstruction time is longer.11,15 These oncologic patients need some surgical interventions and a longer consolidation period. It is frequently necessary to use small bone grafts to join
together the distracted bone and the distal stump (iliac crest and calvaria). Possible complications of the procedure include discomfort (most frequent in intraoral devices), intra- or extraoral exposure of the device, premature consolidation, device breakdown, and implant failure.7 In 1 case, the authors observed a deviation of the contralateral maxilla to the bone defect because of soft tissue forces during the distraction period. This was solved by Le Fort I osteotomy to reposition the maxilla. In conclusion, BDO offers an excellent alternative to conventional techniques in maxillary defects with low morbidity. Zygomatic distraction is a feasible method in hemimaxillectomy defects, which restores lower maxilla projection and allows for dental implant rehabilitation.
References 1. Neelakandan RS, Mathew PC: Intraoral maxillary transport distraction: A case report. J Oral Maxillofac Surg 67:1751, 2009 2. Triana RJ, Uglesic V, Virag M, et al: Microvascular free flap reconstructive options in patients with partial and total hemimaxillectomy defects. Arch Facial Plast Surg 2:91, 2000 3. Dallan I, Lenzi R, Sellari-Franceschini S, et al: Temporalis myofascial flap in maxillary reconstruction: Anatomical study and clinical application. J Craniomaxillofac Surg 37:96, 2009 4. Santamaria E, Cordeiro PG: Reconstruction of maxillectomy and midfacial defects with free tissue transfer. J Surg Oncol 94:522, 2006 5. Snyder CC, Levine GA, Swanson HM, et al: Mandibular lengthening by gradual distraction: Preliminary report. Plast Reconst Surg 51:506, 1973 6. Rubio-Bueno P, Naval L, Rodriguez-Campo F, et al: Internal distraction osteogenesis with unidirectional device for reconstruction of mandibular segmental defects. J Oral Maxillofac Surg 63: 598, 2005 7. Gonzalez-Garcıa R, Naval-Gıas L: Transport osteogenesis in the maxillofacial skeleton. Arch Otolaryngol Head Neck Surg 136: 243, 2010 8. Rachmiel A, Potparic Z, Jackson IT, et al: Midface advancement by gradual distraction. Br J Plast Surg 46:201, 1993 9. Cheung LK, Zhang Q, Zhang ZG, et al: Reconstruction of maxillectomy defect by transport distraction osteogenesis. Int J Oral Maxillofac Surg 32:515, 2003 10. Kashiwa K, Kobayashi S, Kimura H, et al: Reconstruction of a severe maxillofacial deformity after tumorectomy and irradiation using distraction osteogenesis and Le Fort I osteotomy before vascularized bone graft. J Craniofac Surg 18:1133, 2007 11. Niu WG, Zao YM, Han XX: Multiplanar and combined distraction osteogenesis for three-dimensional and functional reconstruction of unilateral large maxillary defects. Br J Oral Maxillofac Surg 47:106, 2009 12. Block MS, Baughman DG: Reconstruction of severe anterior maxilla defects using distraction osteogenesis, bone grafts, and implants. J Oral Maxillofac Surg 63:291, 2005 13. Cheung LK, Zhang Q: Healing of maxillary alveolus in transport distraction osteogenesis for partial maxillectomy. J Oral Maxillofac Surg 62:66, 2004 14. Constantino PD, Shybut G, Friedman CD, et al: Segmental mandibular regeneration by distraction osteogenesis: An experimental study. Arch Otolaryngol Head Neck Surg 116:535, 1990 15. Fujioka M, Kanno T, Mitsugi M, et al: Oral rehabilitation of a maxillectomy defect using bone transport distraction and dental implants. J Oral Maxillofac Surg 68:2278, 2010