Annals of Maxillofacial Surgery

ORIGINAL ARTICLE - PROSPECTIVE STUDY
Year
: 2019  |  Volume : 9  |  Issue : 2  |  Page : 319--325

Creation of bone and soft tissue in postmaxillectomy patients using curvilinear transport distraction osteogenesis


Rushdi Hendricks1, George Vicatos2,  
1 Department of Medicine, Division of Pulmonology, Faculty of Health Sciences, University of Cape Town, Rondebosch, South Africa
2 Department of Mechanical Engineering, University of Cape Town, Rondebosch, South Africa

Correspondence Address:
George Vicatos
Department of Mechanical Engineering, University of Cape Town, Rondebosch 7701
South Africa

Abstract

Background: Large surgical defects in the maxilla due to trauma or tumor are usually reconstructed with revascularized-free fibula flaps (RFFF). In the past, the use of curvilinear transport distraction osteogenesis (CTDO) has been shown to be an efficacious way in closing large defects in the maxilla, but it had limitations which have now been overcome by the present development. The present distractor is an improvement upon the previous three prototypes and employs the concept of tetrafocal distraction by means of hybridizing the bone with the tooth in the transport disc segment. This article aims to prove that tetrafocal distraction provides a viable alternative to the RFFF. Materials and Method: In a prospective cohort study of six postmaxillectomy patients, the method of CTDO was applied and investigated to ascertain the outcome. The regenerate bone was compared with the parent bone, using a new maxillary transport distractor. A linear bicortical fracture was created in the maxilla in a vertical direction (segmentally) to develop a mobile, vascularized transport disk. This transport disk underwent further subdivision to produce the concept of tetrafocal distraction. Results: After osseointegration of the dental implants, prosthetic rehabilitation of the dentition was successful. The authors report the successful outcome of two of the six cases subjected to CTDO to treat defects ranging from 25 mm (using bifocal distraction) to 80 mm along a curved trajectory (using tetrafocal distraction). Conclusions: The production of curvilinear bone and soft tissue along a horizontal plane has been demonstrated. From a clinical perspective, the new alveolar bone achieved the correct width and height to create a physiological vestibule and an esthetic zone for dental implants. In addition, the shape of the palatal vault is also reconstituted. The tetrafocal method of the CTDO is a reliable method of maxillary reconstruction.



How to cite this article:
Hendricks R, Vicatos G. Creation of bone and soft tissue in postmaxillectomy patients using curvilinear transport distraction osteogenesis.Ann Maxillofac Surg 2019;9:319-325


How to cite this URL:
Hendricks R, Vicatos G. Creation of bone and soft tissue in postmaxillectomy patients using curvilinear transport distraction osteogenesis. Ann Maxillofac Surg [serial online] 2019 [cited 2020 Mar 29 ];9:319-325
Available from: http://www.amsjournal.com/text.asp?2019/9/2/319/272608


Full Text



 Introduction



Maxillary defects caused by trauma or tumor resection in the head-and-neck region can be devastating to the patient from a cosmetic and functional perspective.[1] The reconstruction of maxillary defects presents a significant challenge to both the surgeon and prosthodontist.[2],[3] The esthetic needs that must be considered comprise the restoration of the mid-facial contour; for this, there needs to be proper anatomical restoration of the bony contours of the cheekbone or mala, the orbital rim, the zygomatic buttress, and the alveolar arch of the maxilla notwithstanding the vault of the hard palate.[4] The latter is germane to swallowing, speech, esthetics, as well as support for velopharyngeal valve competence.[5]

The revascularized free fibula flaps (RFFF) offer the most functional solution for postmaxillectomy rehabilitation, as the quality of the bone is ideal to house dental implants. In addition, the skin paddle of composite flaps can be used to obturate the palatal vault and close any associated defects.[6] This method of reconstruction can still be regarded as the gold standard in centers, where high expertise and technical facilities are available. Usually, donor-site morbidity and postoperative complications are not high in these units.[7] However, as the maximum height of the fibula bone is 14 mm, this presents problems in the esthetic zone of the mouth.[8],[9] In addition, dental implants would support very high prosthetic superstructures to approximate the occlusal plane. These superstructures pose the risk of unfavorable bending movements and also implant overload. The latter may jeopardize the long-term survival of dental implants.[10],[11] While skin does not do well with dental implants in the long term owing to the hyperplasia and inflammation that leads to pain and bleeding, the flatness of the skin paddle cannot reproduce an anatomical vault of the hard palate.[7]

The concept of transport distraction osteogenesis for the creation of new bone and soft tissue is well described.[12],[13],[14],[15],[16],[17] However, the creation of bone and soft tissue along a curved trajectory has only recently been successfully accomplished in the maxilla.[18],[19] The present distractor is an improvement on the previous three prototypes [14] and employs the concept of tetrafocal distraction by means of hybridizing the bone with the tooth in the transport disk segment [Figure 1]. This article describes the new design as well as the modification of the surgical protocol.{Figure 1}

 Materials and Methods



Preoperative Planning

A three-dimensional (3D) stereolithographic model was fabricated from the computerized tomogram (CT) scan of a patient who had a Brown IIa postmaxillectomy defect.[2],[3] In [Figure 2]a, the 3D model and the anatomical outlines of the teeth in the bone are illustrated. In [Figure 2]b, the adaptation of the baseplate to the model (to plan the position of the transosseous screws) can be seen. A “tandem” distractor would be placed to distract between the teeth in distinct phases. The design of the slot in the baseplate allows for deviation in dental root anatomy so that transosseous screws can be placed strategically to avoid the dental roots during fixation [Figure 3].{Figure 2}{Figure 3}

The fixing of the vertical distraction plates to the locomotive (bone transport carriage) was designed so that, after the first stage of distraction, by merely sectioning the small horizontal crossbars, the locomotive can be freed to continue with the second phase of distraction [Figure 4]. On the model in [Figure 5]a, it can be seen that the trajectory rail is adapted with the device to clear the zygomatic buttress. In [Figure 5]b, a mark was made for the area where bone is indicated for removal during surgery from the inferior aspect of the corpus malar.{Figure 4}{Figure 5}

Surgical procedure and installation of device

A general anesthetic was administered to the patient. The anterior maxillary bone was exposed through a circumvestibular incision [Figure 6]a. The baseplate was secured to the premaxillary bone, considering the position of the roots of the teeth. The insertion of 2.5 mm diameter titanium screws (Biomet ™) ensured a good stability of the baseplate [Figure 6]b. Extra care was taken to ensure that the trajectory rail remained parallel to the occlusal plane of the mandible, and that the position of the locomotive and the vertical distraction plates coincided with the teeth below which make up the transport disk. [Figure 7] confirms the correct relationship of the distraction plates and the underlying teeth. Intraosseous screws secured the vertical distraction plate to the alveolar bone superiorly.{Figure 6}{Figure 7}

In addition, care was taken to ensure that the trajectory rail be kept clear from any soft tissue, namely, cheek muscle or buccal mucosa, to allow free access to and mobility of the locomotive. [Figure 8] shows the removal of bone from the corpus malar to allow unobstructed movement of the locomotive.{Figure 8}

The crowns of the anterior teeth were prepared for bonding to the vertical plates of the transport disk. The surrounding environment was cordoned off from the anterior teeth by means of dry gauze to provide a desiccated environment. The crowns of teeth #12 and #13 were treated with acid etch gel and bonding agent which were cured with ultraviolet light. The transport disk was created by horizontal and vertical osteotomies in the bone [Figure 9].{Figure 9}

In this upgraded distractor, the locomotive could be removed and replaced repeatedly. This two-part system facilitated the process of installation, in which the trajectory rail could be attached and removed as needed. [Figure 10] shows the distraction plates cemented to the crowns of the teeth with glass ionomer cement. The baseplate was submerged under the soft tissue of the upper lip, taking care not to obstruct access to the activation screw on the locomotive. The exposed trajectory rail is also evident.{Figure 10}

Commencement of distraction

After a latency period of 5 days, distraction was commenced. Distraction was carried out at a rate of 1 mm/day and a rhythm of 0.5 mm twice daily.[20],[21] After 20 days, the first phase of distraction was terminated. As shown in [Figure 11]a and [Figure 11]b, the healthy new regenerate in the premaxillary region measured approximately 20 mm with a curvilinear appearance. In the hard palate, the presence of a palatal vault was visible and rugae replication was also noted in the palatal mucosa. Once distraction reached the cornerstone of the maxilla, it was terminated so that a blended curvature could be arrived during the second phase of distraction. The latter images show excellent reproduction of regenerate with anatomical replication of parent alveolar and palatal bone. This proved to be the ideal in optimizing function and esthetics. The immature bone was allowed to consolidate for 10 weeks.[22],[23],[24],[25],[26],[27]{Figure 11}

Second phase of distraction

Under general anesthesia, the soft tissue was elevated, and the transport disk was exposed. The horizontal metal bars supporting the two vertical plates of the distraction apparatus were cut using a tungsten carbide burr (SS White ™ #702) [Figure 12]a and [Figure 12]b. A reciprocating saw was used at the bone interface, and a new osteotomy was performed in a vertical fashion between the remaining teeth in the transport disk. After tooth #22 was secured to the trajectory rail by means of a wire ligature [Figure 13], the mobile segment (transport disk) created by means of an osteotome [Figure 14] was tested for unhindered movement and then returned to its original position for another period of latency.{Figure 12}{Figure 13}{Figure 14}

After a latency period of 5 days, the locomotive was activated at a rate of 1 mm/day and a rhythm of 0.5 mm twice daily. An acrylic spacer was wired to the abutment teeth to maintain the newly created space and provide stability [Figure 15]. The latter also showed the recreated palatal vault with rugae and a “tuberosity” appearance. A further 18 mm was added to the maxilla which amounted to a total distraction of 38 mm. The amount of new regenerate bone and soft tissue was sufficient for the placement of dental implants. [Figure 16] shows the secured acrylic spacer in position, and the newly created regenerate which is on a curvilinear trajectory.{Figure 15}{Figure 16}

Final phase: Surgical exposure of regenerate and placement of dental implants

A general anesthetic was administered. In [Figure 17]a, the new maxilla can be seen before removal of the distraction apparatus. The trajectory rail and the rest of the distraction device were removed. The incisor and canine teeth were carefully removed so that the sockets of the teeth could be preserved for the placement of dental implants [Figure 17]b.{Figure 17}

A clear acrylic splint was fabricated by a prosthodontist using a CT scan of the maxilla. The splint fitted accurately during the placement of dental implants into the new maxilla. The availability of this thick regenerate made it possible to place four dental implants with good primary stability into the new maxilla. [Figure 18]a shows the acrylic splint in situ and [Figure 18]b shows placement of the dental implants. As can be seen in [Figure 19]a, the dental implants were well placed with healing abutments. Bone scrapings were taken from the areas of excess tissue and placed into the sockets around the dental implants to accelerate osseointegration. There was good bony union between the regenerate and the malar corpus, and hence, no interpositional bone grafting was required in this case. [Figure 19]b shows primary soft tissue closure around all the dental implants.{Figure 18}{Figure 19}

There was sufficient torque at implant placement for an immediate esthetic temporary bridge to be constructed. [Figure 20] shows the implant-supported temporary bridge.{Figure 20}

 Results



The use of curvilinear transport distraction osteogenesis (CTDO) has created not only new alveolar bone with its attendant depth creating a vestibule but also a palatal vault. The shape, depth, and anatomical accuracy of the regenerated maxilla are evident. [Figure 15] shows the superlatively recreated palatal vault with rugae in the palate.

In [Figure 18]b, the regenerated bone can be seen as well as the preserved sockets of the anterior teeth. The quality of the regenerated bone with its thick buccal plate as well as the healthy tooth sockets, made it conducive to the placement of dental implants. A temporary bridge was constructed onto the implants, [Figure 20] and [Figure 21]a and [Figure 21]b.{Figure 21}

Bone density of second-phase regenerate

The bone density of the new regenerate at 3 months, compared favorably with the bone density of the regions of interests seen within the parent bone. The CT scan of the maxilla, [Figure 22], shows the 3-month state of the new bone expressed in Hounsfield units.[28]{Figure 22}

A CT scan of the maxilla [Figure 23] shows tetrafocal distraction (of another patient) at the 3-month and 6-month intervals of new bone formation, expressed in the HU. The second phase of regenerate compared favorably with the first phase, which, in turn, compared favorably with the parent bone. This clinical situation is shown in [Figure 24].{Figure 23}{Figure 24}

 Discussion



The development of the current distractor was due to the paucity of teeth available for the creation of bone stock, which led to the concept of hybrid distraction. Concurrently, the new design of the distractor allows the mobile component to be split into segments; hence, the term “Tandem distractor.” This concept eliminated the problem of the weak anchoring of the transport disk onto its cradle as previously described by Boonzaier et al. in 2015.[18]

The current device caters for a distraction length of up to 100 mm including a minimum bend radius of 25 mm. This means that in severe cases, the device can distract from one side of the maxilla to the other, transcending the premaxilla, and centerline of the maxilla.

As shown by Neelakandan amd Bhargava in 2012, it is not possible to grow bone on a curvilinear trajectory in a horizontal plane.[29] The regenerate will follow the shortest distance between two points, hence creating a straight line, which is known as the “rubber band” effect. With the “tandem distractor” eliciting tetrafocal distraction, as shown in [Figure 24], the bone was grown following the curvature of the premaxilla, using the method of creating a second (and possibly a third) transport disk from the first one.

The quality of the newly created bone was found to be more than satisfactory, and the teeth that were transported were eventually extracted, and dental implants were placed into their respective sockets. The results of the bone that was produced are shown in [Figure 24], [Figure 25]a and [Figure 25]b.{Figure 25}

During distraction and transport of the teeth, it was noted that premature contacts with the mandibular occlusion occurred. To avoid this complication, a sectional removal acrylic bite appliance was made [Figure 26]. Further, to prevent relapse of the new segments of the regenerated bone (between the first and the second transport disk), an acrylic spacer was placed between the teeth [Figure 16] and [Figure 26].{Figure 26}

It was significant that the abutment teeth between the areas of bone regenerate did not have any axial or nonaxial forces imposed upon them so that healing of the osteoid around these teeth would not be compromised.

 Conclusions



In the present study, the production of curvilinear bone and soft tissue along a horizontal plane has been clearly demonstrated, as well as the quantity and the quality of the newly created bone and soft tissue. From a clinical perspective, the new alveolar bone achieved all the goals that were set out, namely the correct width and height to create a physiological vestibule and palatal vault shape. In addition, the depth to reestablish the shape of the hard palate as well as the integrity to place dental implants in the esthetic zone was also achieved. This clinical picture is well demonstrated in [Figure 20] and [Figure 21]. The anatomical landmarks mentioned above are not seen in the RFFF.

The method of CTDO as described has been shown to be a reliable method of maxillary reconstruction. The HU produced by CTDO was sufficient for dental implant placement after 3 months. Besides providing hermetic closure of the orosinonasal cavities, this method of CTDO also maximizes function and esthetics.

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

The CTDO device was designed and developed by the authors and manufactured by a state-of-the-art industry in Cape Town, TiTaMED. Its design and manufacturing were financed entirely by the authors, by the Postgraduate Fund of the University of Cape Town (UCT), and by the ATTRI Orthopaedics (Pty) Ltd. UCT has also financed the application and maintenance of the patent with reference: US2014/0324046 A1 and PCT/1B2012/056664.

It is envisaged that the CTDO device would be commercially available and distributed by a South African company.

Conflicts of interest

There are no conflicts of interest.

References

1Peng X, Mao C, Yu GY, Guo CB, Huang MX, Zhang Y. Maxillary reconstruction with the free fibula flap. Plast Reconstr Surg 2005;115:1562-9.
2Mücke T, Hölzle F, Loeffelbein DJ, Ljubic A, Kesting M, Wolff KD, et al. Maxillary reconstruction using microvascular free flaps. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111:51-7.
3Jaquiéry C, Rohner D, Kunz C, Bucher P, Peters F, Schenk RK, et al. Reconstruction of maxillary and mandibular defects using prefabricated microvascular fibular grafts and osseointegrated dental implants – A prospective study. Clin Oral Implants Res 2004;15:598-606.
4Rohner D, Kunz C, Bucher P, Hammer B, Prein J. New possibilities for reconstructing extensive jaw defects with prefabricated microvascular fibula transplants and ITI implants. Mund Kiefer Gesichtschir 2000;4:365-72.
5Hoshaw SJ, Brunski JB, Cochran GV. Mechanical loading of brånemark implants affects interfacial bone modeling and remodeling. Int J Oral Maxillofac Implants 1994;9:345-60.
6Weischer T, Mohr C. Ten-year experience in oral implant rehabilitation of cancer patients: Treatment concept and proposed criteria for success. Int J Oral Maxillofac Implants 1999;14:521-8.
7da Silva SD, Ferlito A, Takes RP, Brakenhoff RH, Valentin MD, Woolgar JA, et al. Advances and applications of oral cancer basic research. Oral Oncol 2011;47:783-91.
8Brown JS, Rogers SN, McNally DN, Boyle M. A modified classification for the maxillectomy defect. Head Neck 2000;22:17-26.
9Brown JS, Shaw RJ. Reconstruction of the maxilla and midface: Introducing a new classification. Lancet Oncol 2010;11:1001-8.
10Zapata U, Elsalanty ME, Dechow PC, Opperman LA. Biomechanical configurations of mandibular transport distraction osteogenesis devices. Tissue Eng Part B Rev 2010;16:273-83.
11Wang JJ, Chen J, Ping FY, Yan FG. Double-step transport distraction osteogenesis in the reconstruction of unilateral large mandibular defects after tumour resection using internal distraction devices. Int J Oral Maxillofac Surg 2012;41:587-95.
12Holbein O, Neidlinger-Wilke C, Suger G, Kinzl L, Claes L. Ilizarov callus distraction produces systemic bone cell mitogens. J Orthop Res 1995;13:629-38.
13Ilizarov GA. Basic principles of transosseous compression and distraction osteosynthesis. Ortop Travmatol Protez 1971;32:7-15.
14Ilizarov GA, Ledyaev VI. The replacement of long tubular bone defects by lengthening distraction osteotomy of one of the fragments 1969. Clin Orthop Relat Res 1992;280:7-10.
15Ilizarov GA. The tension-stress effect on the genesis and growth of tissues. Part I. The influence of stability of fixation and soft-tissue preservation. Clin Orthop Relat Res 1989;238:249-81.
16Ilizarov GA. The tension-stress effect on the genesis and growth of tissues: Part II. The influence of the rate and frequency of distraction. Clin Orthop Relat Res 1989;239:263-85.
17Ilizarov GA. Clinical application of the tension-stress effect for limb lengthening. Clin Orthop Relat Res 1990;250:8-26.
18Boonzaier J, Vicatos G, Hendricks R. Repair of segmental bone defects in the maxilla by transport disc distraction osteogenesis: Clinical experience with a new device. Ann Maxillofac Surg 2015;5:85-8.
19Hendricks MR, Hallund M, Singh S. Reconstruction of partial maxillectomy defect by transport distraction osteogenesis. Int J Oral Maxillofac Surg 2007;36:1091.
20Djasim UM, Wolvius EB, Bos JA, van Neck HW, van der Wal KG. Continuous versus discontinuous distraction: Evaluation of bone regenerate following various rhythms of distraction. J Oral Maxillofac Surg 2009;67:818-26.
21Djasim UM, Wolvius EB, van Neck JW, Weinans H, van der Wal KG. Recommendations for optimal distraction protocols for various animal models on the basis of a systematic review of the literature. Int J Oral Maxillofac Surg 2007;36:877-83.
22Aizenbud D, Hazan-Molina H, Thimmappa B, Hopkins EM, Schendel SA. Curvilinear mandibular distraction results and long-term stability effects in a group of 40 patients. Plast Reconstr Surg 2010;125:1771-80.
23Boulétreau P, Longaker MT. The molecular biology of distraction osteogenesis. Rev Stomatol Chir Maxillofac 2004;105:23-5.
24Chin M, Toth BA. Distraction osteogenesis in maxillofacial surgery using internal devices: Review of five cases. J Oral Maxillofac Surg 1996;54:45-53.
25McCarthy JG, Schreiber J, Karp N, Thorne CH, Grayson BH. Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 1992;89:1-8.
26Saulacic N, Iizuka T, Martin MS, Garcia AG. Alveolar distraction osteogenesis: A systematic review. Int J Oral Maxillofac Surg 2008;37:1-7.
27Snyder CC, Levine GA, Swanson HM, Browne EZ Jr. Mandibular lengthening by gradual distraction. Preliminary report. Plast Reconstr Surg 1973;51:506-8.
28Razi T, Niknami M, Alavi Ghazani F. Relationship between hounsfield unit in CT scan and gray scale in CBCT. J Dent Res Dent Clin Dent Prospects 2014;8:107-10.
29Neelakandan RS, Bhargava D. Transport distraction osteogenesis for maxillomandibular reconstruction: Current concepts and applications. J Maxillofac Oral Surg 2012;11:291-9.