|Year : 2020 | Volume
| Issue : 4 | Page : 240-243
Reconstruction of postsurgical mandibular defect (keratocystic odontogenic tumor) by transport distraction osteogenesis
S Devakumari, Neil Dominic
Department of Dentistry, Indira Gandhi Medical College and Research Institute, Puducherry, India
|Date of Submission||22-Oct-2019|
|Date of Acceptance||09-Jan-2020|
|Date of Web Publication||28-Sep-2020|
Dr. S Devakumari
Department of Dentistry, Indira Gandhi Medical College and Research Institute, Puducherry - 605 008
Source of Support: None, Conflict of Interest: None
Reconstruction of mandibular surgical defects often poses a great challenge to maxillofacial surgeons. Mandibular segmental defects majorly disrupt the occlusion, mastication, and the facial esthetics. Free autografts such as iliac crest and rib; allografts such as three-dimensional, bendable reconstruction plate; and patient-specific implant are some of the techniques that had been employed for the reconstruction of such defects. Nevertheless, in recent times, the most dependable modes of reconstruction are the microvascular fibula reconstruction and transport distraction techniques. Transport distraction osteogenesis (TDO) is a reliable technique without donor-site morbidity especially in the dentate region of the mandible as it provides native bone for rehabilitation. The aim of this article is to report a successful case of TDO to fill the defect in the left body of the mandible secondary to segmental resection of the mandible for keratocystic odontogenic tumor. The technique was successful with a 2-year follow-up period without any potential esthetic compromise.
Keywords: Distraction osteogenesis, keratocystic odontogenic tumor, mandible, reconstruction, transport distraction
|How to cite this article:|
Devakumari S, Dominic N. Reconstruction of postsurgical mandibular defect (keratocystic odontogenic tumor) by transport distraction osteogenesis. Turk J Plast Surg 2020;28:240-3
|How to cite this URL:|
Devakumari S, Dominic N. Reconstruction of postsurgical mandibular defect (keratocystic odontogenic tumor) by transport distraction osteogenesis. Turk J Plast Surg [serial online] 2020 [cited 2020 Oct 29];28:240-3. Available from: http://www.turkjplastsurg.org/text.asp?2020/28/4/240/296476
| Introduction|| |
Mandibular segmental defects greatly demand a functional and esthetic reconstruction. Management of young patients with benign odontogenic tumors always necessitates the need for dependable and long-term reconstruction. In the present case, reconstruction with native bone suitable for future implant placement was the ideal requirement of the clinical situation. Transport distraction osteogenesis (TDO) and histiogenesis provides the newly formed native bone at the mandibular site that would be suitable for dental implant placement, eliminating the donor-site morbidity. The bone formed in TDO is usually of adequate alveolar height, width, and attached gingiva.
| Case Report|| |
A 24 years old female patient reported to the Department of Dentistry, IGMCRI, with a complaint of painless swelling on the left side of the jaw for the past 2 weeks. Intraoral periapical radiograph revealed a supernumerary tooth with multilocular radiolucency in relation to 34 and 35. An orthopantomogram (OPG) revealed a multilocular radiolucency from 34 to 37 regions [Figure 1]. Computed tomography (CT) scan images showed a radiolucent lesion with supernumerary teeth in the mandible (45 mm) [Figure 2] and [Figure 3]. Histopathological examination identified the lesion as a keratocystic odontogenic tumor.
The surgical team proposed a segmental resection and reconstruction technique as the lower border of the mandible appeared thinned out as observed on the CT and OPG images. The defect involved two vectors of the mandible, namely the parasymphysis and the body of the mandible. An indigenous bifocal intraoral transport distractor (Sirag Surgicals, Chennai, Tamil Nadu, India) was fabricated using medicalgrade stainless steel material for the anticipated defect as per the CT measurements. Surgery was done after obtaining appropriate Informed consent from the patient.
The transport distraction device can be divided into three parts, that is, a stable reconstruction plate, a mobile distractor assembly to perform TDO on activation, and the screws for fixing the device. Besides an activation key, the device had an extraoral extension to activate, which was led through the stab incision in the post angle region. Segmental resection of keratocystic odontogenic tumor was done with a 2-cm margin [Figure 4]. A transport disc for TDO was planned involving teeth 31 and 41. The teeth were not extracted. Care was taken not to strip the periosteum on the lingual aspect. The transport distractor [Figure 5] was adapted and fixed with 2 mm × 8 mm-stainless steel screws and checked for proper movement in the reconstruction plate. The transport disc was fixed with four screws. The distractor was fixed with 2.5 mm × 8 mm-screws, two on either side. A latency period of 7 days was allowed following which distraction was done at 1 mm/day for 45 days, that is, till the bone reached the docking site. A rate of 1 mm/day and rhythm once daily (2½ turns with the key) was adopted. A consolidation period of 12 weeks [Figure 6] was allowed, after which the distractor was removed with grafting and refreshing of bony segments in the docking site. A 2-mm plate was fixed between the newly formed bone and the docking site. The patient's profile and intraoral bone regenerate was very much acceptable by the patient [Figure 7] and [Figure 8].
A bone regenerate of adequate width except at the docking-site region was formed. As far as the height of regenerate is concerned, the height decreased when it reached the docking site [Figure 9] and [Figure 10]. This is due to the fact that it involved the arched (two vectors) defect. The regenerate formed was straight as it involved two vectors. During the 2-year follow-up visit, clinical and radiographic examinations revealed that the patient now had a stable regenerated bone by TDO that supports a distal extension removable partial denture. Currently, an implant placement is scheduled in the near future.
|Figure 9: Postoperative three-dimensional computed tomography basal view|
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|Figure 10: Postoperative three-dimensional computed tomography frontal view|
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| Discussion|| |
Mandibular segmental defect reconstruction constitutes challenges of reconstruction of osseous defect in length, breadth, and height along with a need for soft-tissue cover for prosthetic options. Reconstruction of horseshoe-shaped arch form for facial esthetics should also be considered. Ultimately, maintaining all the above parameters without resorption of the distracted bone over the years leads to the success of this uphill task.
TDO leads to the formation of a new bone and a soft tissue behind the transport segment till the docking site is reached due to incremental traction. Distraction osteogenesis was popularized by Ilizarov for long bones in the 19th century. Snyder et al. in 1973 conducted distraction in the craniofacial skeleton. Mandibular distraction was developed by Michieli and Miotti. Costantino et al. were the first to do TDO with an external custom-made distractor for the regeneration of 40 mm of mandibular defect.
According to Zhang and Zhang, 3–12 cm of defect can be optimally reconstructed by TDO. Heffez and Kirton studied on vector control in TDO and studied that proper vector control in TDO obviates the need for bone graft. Defects involving single vector resulted in a good straight regenerate of bone than defects involving more than one vector, that is, arched defects. TDO produces tensile stretching of the osteoblasts and in turn it increases the growth factors. A properly done surgical technique maintains an adequate blood supply to the distal limbs, that is, the transport disc. With the increase in blood supply, formation of the callus can be appreciated with hyperechoic areas on the ultrasound. Microvascular tissue transfer necessitates extensive surgical procedure with donor-site morbidity. Moreover, rehabilitation of the oral cavity with dental implant always proves better with native bone than the grafted bone. In addition, TDO provides excellent regenerate of native bone mandible with labial and lingual vestibule suitable to receive a dental implant or removable prosthesis.
Free flaps were many times associated with infection and inadequate bone for implant placement. Segmental defects of mandible require bifocal or trifocal TDO. Gantous et al. demonstrated distraction in previously irradiated mandible.
Shvyrkov et al. used teeth in the transport segment for rehabilitation with bridge. Herford and Block et al., recommended extraction of teeth 2 weeks prior to surgery. In our case, we extracted the teeth during the second surgery to remove the distractor.
The bone regenerate formed was well appreciated during a 3-month follow-up on the radiographs. The bone height and width were adequate or more than adequate in width in the parasymphysis region. The height of the bone decreased as it reached the docking site, leading to an hourglass-shaped defect. This was further due to infection of the docking site at the end of 12 weeks. This region was decorticated and grafted with an osseograft (allogeneic bone graft). We further observed the union of docking site with bony regenerate at the lower border. Clinically, the patient had no complaints of mobility or food entrapment in the defect with a follow-up of 2 years.
TDO is an excellent treatment modality for the reconstruction of segmental defects of mandible. TDO can be recommended for patients who cannot undergo extensive microvascular surgeries or in case of failed microvascular grafts. It is a promising technique with lots of successful case reports worldwide. The only disadvantage would be patient compliance owing to prolonged treatment with the distractor.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]