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J Oral Maxillofac Surg70:1739-1744, 2012

Mandibular Reconstruction UsingExtraoral Trifocal Bone Transport: Report

of a Case Using a New Device

Rajiv Agarwal, MCh,* Sanjeev Agarwal, FRCS, FRCSEd,† and

Ramesh Chandra, FRCS‡

A newly designed mandibular stabilization andtransport distraction system is an extraoral assem-bly of a half-elliptical rod, with movable clampattachments that serves the dual purpose of stabili-zation and transport distraction osteogenesis ofmandibular segmental defects. The rod is threadedand made of stainless steel, and it conforms to theshape of the human mandible. Mandibular stabiliza-tion and bone transport are accomplished with thehelp of different assemblies that are attached ontothis rod. There are 3 different assemblies havingseparate functions but achieving the same goals ofmandibular stabilization and bone transport. All theassemblies have a common base unit that moves onthreads of the curved rod in a graduated manner,controlled by a spanner. One full turn of 360°moves the assembly by a distance of 1 mm. The firstassembly is the stabilization assembly, which helpsin the rigid fixation of the frame to the mandible byuse of at least 2 clamp units on either side of themidline. It helps in stabilization of the mandibularsegments in an anatomic position. The bone trans-port assembly consists of 1 or 2 moveable clampassemblies that are fixed at 1 end to the transportdisc of the mandible, while the base unit assemblyglides and engages on the threads of the distractionrod. This allows bone regeneration and laying downof new bone in the natural position along the pathof movement of the transport disc in a curvilinearmanner. This system allows mandibular regenera-

*Professor, Department of Plastic Surgery, Chhatrapati Shahuji

Maharaj Medical University, Lucknow, India.

†Consultant Orthopaedic Surgeon, Cardiff and Wales NHS Trust,

University Hospital of Wales, Cardiff, United Kingdom.

‡Former Professor and Head, Department of Plastic Surgery, King

George’s Medical College, Lucknow, India.

Address correspondence and reprint requests to Dr Agarwal:

A-15 Nirala Nagar, Lucknow 226020, India; e-mail: drrajivagarwal@

rediffmail.com

© 2012 American Association of Oral and Maxillofacial Surgeons

278-2391/12/7007-0$36.00/0

oi:10.1016/j.joms.2011.06.218

1739

tion along the original topography of the bone. Thethird assembly is the multivector distraction assem-bly, which is also mobile at 1 end on the distractionrod, while the other end is anchored to the mandi-ble through incorporation of a distraction rod and360° swivel joint. This arrangement allows mandib-ular distraction in the vertical and transverse axesin addition to the horizontal mandibular distractionperformed by the bone transport assembly (Fig 1).

Thus the system of 3 assemblies allows mandiblestabilization along with bone regeneration in all thex-, y-, and z-axes, and hence paves the way forrepair and regeneration of challenging defects ofthe mandible. The application of this system is easy;the first step is to visualize the device on the patientand mark the sites for pin holes for the 2 clamps ofthe stabilization assembly. The number of transportdiscs is also planned depending on the size of thedefect. One transport disc is used in bifocal distrac-tion, and two transport discs are required for trifocaldistraction. Schanz screws are drilled into the bone ofthe ascending ramus on both sides, and the device isthen assembled after putting together the stabilizationand transport distraction assemblies onto the rod. Theassemblies can be activated by the surgeon using aspanner, and this subsequently can be performed bythe patient’s attendant under supervision. The systemis well tolerated by the patient and does not interferein the daily routine.

Case Report

A 17-year-old boy had a mandibular discontinuity onthe right side resulting from a road traffic accident withsevere facial injury (Fig 2A). After the injury, a segment ofthe right part of the body of the mandible, along with theteeth, was avulsed and devitalized and was loosely hang-ing with a thin pedicle of mucosa. It was debrided, andthe mandibular segments were stabilized by use of archbars, after which he was referred for definitive manage-ment. The left lower incisors, canine, and first premolarwere also loose. In addition, he had fractures of theramus and the coronoid on the left side. The patient wasreferred to us 2 weeks after injury, at which time theramus fracture was in the healing stage with adequate

alignment; hence, it did not require any treatment. A

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1740 EXTRAORAL TRIFOCAL BONE TRANSPORT USING NEW DEVICE

panoramic radiograph showed a segmental defect in theright mandible extending from the right central incisor tothe right first molar region, measuring 60 mm, withassociated soft tissue loss (Fig 2B). The oral hygiene ofhe patient was improved, and trifocal distraction osteo-enesis was planned by use of the new mandibular sta-ilization and transport distraction device after approvalrom the local institutional review board. The loose leftower incisors, canine, and first premolar were extractedt the time of surgery. One osteotomy on each segmentf the mandible was performed, making two 1.5- to.0-cm transport discs at the free end of the segments.he device was used to stabilize the mandible, and the

ransport discs were connected to the transport distrac-ion assemblies to allow mandibular distraction along theatural curved contour of the mandible. Distraction wastarted after a latency period of 5 days at the rate of 1m/d in both transport discs. This was continued until

he time when both the transport distraction assemblieset each other at a point in the center of the defect, after

0 days (Fig 3). The ends of both transport discs werehen decorticated intraorally with the patient under local

FIGURE 1. Mandibular stabilization and transport distraction syshich conforms to the shape of the mandible. C, Transport distracti

panner. F, Device fixation screwdriver. G, Multivector distraction

garwal, Agarwal, and Chandra. Extraoral Trifocal Bone Trans

nesthesia, and the distractor was activated to compress

the bone ends together, thereby leading to compressionosteosynthesis. The device was left in place for a further12 weeks for consolidation to occur. The device wasremoved thereafter, and minor soft tissue procedureswere performed at this time to reconstruct the oral com-missure on the right side, along with revision of the chinscars. The patient was followed up for 10 months toobserve the newly formed bone radiologically (Fig 4A).The follow-up panoramic radiographs showed satisfac-tory bone regeneration, which was further confirmedby documenting neo-callus formation and neovasculari-zation on color Doppler examination during the period oftransport distraction (Fig 4B). Postoperative computedtomograms after the removal of the device show the 2transport discs along with callus formation on each sideof the discs (Fig 4C). The patient is doing well at 1.5years’ follow-up and has healthy restoration of gingivalheight over the area of segmental defect (Fig 4D). He hasan acceptable cosmetic appearance of the face and in-gests a semisolid diet with normal speech and compe-tency of the mouth (Fig 4E). He was advised to undergo

, Stabilization assembly. B, Half-elliptical, threaded, curved rod,mbly. D, Multivector distraction assembly. E, Transport distractionriver (patent pending).

ing New Device. J Oral Maxillofac Surg 2012.

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AGARWAL, AGARWAL, AND CHANDRA 1741

the restoration of the missing teeth but refused any fur-ther treatment.

Discussion

The bone transport method for treating segmentaldefects was developed by Ilizarov1 and was furthercorroborated in animal experiments for the recon-struction of symphyseal defects.2 The treatment ofsegmental mandibular defects is challenging becausethese patients have many problems, including facialdeformity; difficulty in eating, breathing, and speech;missing teeth; oral incompetency; and persistent sal-ivation. The goals of treatment of mandibular discon-tinuity defects envisage reconstruction of anatomic

FIGURE 2. A, Frontal photograph of a 17-year-old boy with a facwith subconjunctival hemorrhage in the left eye. B, Panoramic radioextending from the right central incisor to the right first molar with

Agarwal, Agarwal, and Chandra. Extraoral Trifocal Bone Trans

continuity of bone, dental restoration, and soft tissue

reconstruction, along with achieving anatomic andfunctional competency of the oral sphincter. Conven-tional treatment by free bone grafts presents a highrate of complications on large defects because themicrovascular bone graft is a complex procedure re-quiring 2 or 3 teams and the cost of treatment is high.Even the microvascular grafts present poor resultswith regard to the shaping of the anterior mandible,increasing the occurrence of complications when os-teotomies must be performed to achieve the mandib-ular contour.3

The availability and versatility of the distractiondevices largely influence the quality of the regen-erate and osseous reconstruction. Many types of

y showing right commissural discontinuity and multiple chin scars,of the same patient showing a 60-mm segmental mandibular defectrary fixation by arch bars.

ing New Device. J Oral Maxillofac Surg 2012.

ial injurgraphtempo

devices, both extraoral4,5 and intraoral,6-8 have

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1742 EXTRAORAL TRIFOCAL BONE TRANSPORT USING NEW DEVICE

FIGURE 3. A, Postoperative frontal photograph showing the mandibular stabilization and transport distraction system in situ. The transportassemblies have met at the midline of the defect, showing the completion of the trifocal distraction phase. B, Postoperative radiograph of theskull at 12 weeks after surgery during the trifocal distraction phase showing the mandibular segments, 2 transport discs, and the regeneratingcallus on both sides, along with the extraoral system in situ.

Agarwal, Agarwal, and Chandra. Extraoral Trifocal Bone Transport Using New Device. J Oral Maxillofac Surg 2012.

FIGURE 4. A, Postoperative panoramic radiograph at 18 weeks after surgery showing restoration of the bony continuity of the mandible withssifying callus on the sides of the transport discs. Both the radiolucent areas on the right ramus represent sites of pin insertion. B, Color Dopplervaluation of the area of the callus on both sides of the transport discs in the mandible shows evidence of new bone formation and blood flow inhe capillaries, proving the presence of new bone formation, as indicated by the red area. The tracing at the bottom measures the blood flow in theeocapillaries. C, Sixty-four–slice computed tomography reconstruction of the mandible after the removal of the system. The tomograms show thetransport discs along with callus formation on each side of the discs. (Figure 4 continued on next page.)

garwal, Agarwal, and Chandra. Extraoral Trifocal Bone Transport Using New Device. J Oral Maxillofac Surg 2012.

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AGARWAL, AGARWAL, AND CHANDRA 1743

been used for distraction osteogenesis of the man-dible and have unique advantages and disadvan-tages. All of the described devices to date for re-generating segmental mandibular defects primarilyuse a straight line vector for bone regeneration ofthe mandible, which is essentially a curved bone. Inaddition, all the currently available devices requirea reconstruction plate for stabilization of the seg-mentally deficient mandible, because they do nothave the capability of stabilizing the mandibular

FIGURE 4 (Cont’d). D, Postoperative radiograph at 10 monthbone. E, Postoperative intraoral photograph showing restoratmandibular ends. F, Postoperative frontal view after 18 monthssthetics.

garwal, Agarwal, and Chandra. Extraoral Trifocal Bone Tra

segments per se. t

The internal devices undoubtedly have the cos-metic advantage of avoiding facial scars because thedevice is submerged, leading to enhanced social ac-ceptability. The advantage comes at a premium of aninability to optimally control the directionality regen-erated bone. Takenobu et al7 reported use of dualnternal devices for intraoral trifocal bone transportnd admitted that there is a need for developmentf an internal device that can be used more easilyhan the currently available devices. The early in-

surgery showing the osseous outline of the newly consolidatedthe defect with healthy gingival tissue present all along thestoration of oral commissure, mandibular continuity, and facial

Using New Device. J Oral Maxillofac Surg 2012.

s afterion ofwith re

raoral distraction devices consisted of a slotted re-

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1744 EXTRAORAL TRIFOCAL BONE TRANSPORT USING NEW DEVICE

construction plate attached to the residual bone seg-ments by screws. More recently, different intraoraldevices were developed for correction of large man-dibular continuity defects, reconstruction of neocon-dyles, and cleft palate treatment.

One of the important issues affecting the ultimateresult of mandibular reconstruction is the abilityof a distraction device to 3-dimensionally manipu-late the bone segments and the distraction regen-erate in the desired direction.9 It is thus clear thatn extraoral semicircular frame-based device couldeet the occlusal and clinical endpoints of segmen-

al mandibular transport better than non–frame-ased devices. The first report of the clinical appli-ation of bone transport using a semicircularxtraoral device was presented in 1995 by Constan-ino et al.10 The device consisted of a semicircularrame attached by 2 pairs of pins to the mandibularegments and a transport tram connected to theransport disc. Klein11 introduced the Frankfurtraniofacial Distraction System, consisting of a U-ow and several sliding clamps to allow stable fix-tion of each bone segment. Fedotov12 used an

extraoral semicircular apparatus for bone transportand presented the results of treatment in 22 pa-tients with post-traumatic defects of varying sizes.

Labbé et al13 described an external horseshoe-haped rod extending between the mandibular ramior bone transport in mandible segmental gunshotound defects. The drawback of this device is that iteeds to be individually designed for each case and,ence, requires customization, which increases theost of the device, along with technical dependencen the manufacturer every time a device is required.his also does not allow universal applicability of theevice. Moreover, the authors admitted that the usef a mobilized bone segment on each side led toroblems with this device because of the presence ofoo many metal appliances on the endless screw,hich came into contact before the bone segments

eached each other. Our system avoids these prob-ems and allows any configuration of the bone trans-ort discs on the mandible (bifocal, trifocal, anduadrifocal) and also does not need to be custom-

zed for each patient every time that such a devices being used. The central elliptical threaded rodomes in 3 different internal diameters but of theame thickness that can fit onto any mandible, rang-ng from children to geriatric patients. The differentssemblies, however, remain the same for any givenhreaded rod. This system also differs from all of thereviously mentioned systems in being additionallyapable of moving the transport disc and/or theandible forward, using the multivector distraction

ssembly in situations that require osseous move-

ent in an anteroposterior direction. Moreover, theescribed system uses a 3-pin triangular pin-holdinglamp, which provides more stability and versatilityo secure the underlying bone to the distractor, aspposed to the use of 2 pins by the previouslyescribed devices. Our system can be used forreating mandibular deficiencies in all age groupsnd indications ranging from congenital absence toypoplasia or post-traumatic loss or after neoplasticesection.

Our system of mandibular stabilization and trans-ort distraction offers result-oriented regenerationf the mandible and gingival tissues molded alonghe natural contour of the bone without the use ofone grafts, bone substitutes, reconstruction platesnd soft tissue pedicled or microvascular proce-ures; moreover, it is reliable and has a high pre-ictive value.

References1. Ilizarov GA: The principles of the Ilizarov method. Bull Hosp Jt

Dis Orthop Inst 48:1, 19882. Annino DJ Jr, Goguen LA, Karmody CS: Distraction osteogen-

esis for reconstruction of mandibular symphyseal defects. ArchOtolaryngol Head Neck Surg 120:911, 1994

3. Soares MM, Paiola D, Guerra F, et al: The uses of distractionosteogenesis on mandibular reconstructive surgery. Int J OralMaxillofac Surg 34:52, 2005 (suppl 1)

4. Block MS, Otten J, McLaurin D, et al: Bifocal distraction osteo-genesis for mandibular defect healing: Case reports. J OralMaxillofac Surg 54:1365, 1996

5. Basa S, Uner E, Citir M, et al: Reconstruction of a large man-dibular defect by distraction osteogenesis: A case report. J OralMaxillofac Surg 58:1425, 2000

6. Hibi H, Ueda M: New internal transport distraction device forreconstructing segmental defects of the mandible. Br J OralMaxillofac Surg 44:382, 2006

7. Takenobu T, Nagano M, Taniike N, et al: Mandibular reconstruc-tion using intraoral trifocal bone transport: Report of a case. OralSurg Oral Med Oral Pathol Oral Radiol Endod 103:630, 2007

8. Hirota M, Chikumaru H, Matsui Y, et al: Osteosynthesis andsimultaneous irregular trifocal distraction osteogenesis for seg-mental mandibular defect after tumour ablative surgery: A casereport. Oral Surg Oral Med Oral Pathol Oral Radiol Endod106:651, 2008

9. Genecov DG, Agarwal R, Genecov ER, et al: Evolution of extraoralmandibular distraction: Case reports, in Samchukov ML, Cope JB,Cherkashin AM (eds): Craniofacial Distraction Osteogenesis. StLouis, MO, Mosby, 2001, pp 230-35

10. Constantino PD, Johnson CS, Friedman CD, et al: Bone regen-eration within a human segmental mandibular defect: A pre-liminary report. Am J Otolaryngol 16:56, 1995

11. Klein C. Bone transport for mandibular anterior defect recon-struction: A case report, in Samchukov ML, Cope JB,Cherkashin AM (eds): Craniofacial Distraction Osteogenesis. StLouis, MO, Mosby, 2001, pp 368-371

12. Fedotov SN: Dosed distraction of the mandible fragments byextra-mouth apparatus in patients with bone defect and man-dible fractures, in Diner PA, Vasquez ZT (eds): InternationalCongress on Cranial and Facial Bone Distraction Processes:Paris, France, June 19-21, 1997. Bologna, Italy, Monduzzi Edi-tore, pp 155-160

13. Labbé D, Nicolas J, Kaluzinski E, et al: Gunshot wounds: Re-

construction of the lower face by osteogenic distraction. PlastReconstr Surg 116:1596, 2005