THE PREFABRICATED COMBINED SCAPULA FLAP FOR BONY AND SOFT TISSUE RECONSTRUCTION IN MAXILLOFACIAL DEFECTS

A NEW METHOD

Holle J, Vinzenz K, Würinger E, Kulenkampff KJ, all Vienna, Saidi M, Tripolis

Abstract

A concept of improving the precision of reconstruction of the maxilla in terms of form and function including gnathological, functional and prosthetic aspects is presented with a prefabricated combined scapula flap. In 4 cases a bony flap from the lateral border of the scapula with osseointegrated titanium implants, covered with skin grafts and encapsulated with a Goretex sheet, to create a stable soft tissue coverage is performed. Three months later the prefabricated combined scapula flap is harvested and transferred to reconstruct a maxillary bony and soft tissue defect in the face using microsurgical vascular anastomosis to the facial vessels. One flap was lost due to vascular thrombosis and could be repeated successfully one year later. In all 4 cases a fully dental rehabilitation and marked improvement of the contour of the face was achieved in a single surgical intervention in the face. For this purpose new radiodiagnostic methods for precise correlation between the maxillofacial defect and the donor area were used. With this new concept an organ- specific reconstruction of soft and bony tissue defects of the alveolar ridge, the hard palate together with a pseudogingiva and teeth are possible in an optimal way.

1. Introduction

In many institutions extensive congenital or acquired combined maxillofacial bony and soft tissue defects are reconstructed by microsurgical transfer of vascularized osteomyocutaneous, osteocutaneous or bony flaps (1,2). Particularly the reconstruction of the alveolar ridge and the hard palate with its tense oral or nasal mucosa lining has certain demands to the selected donor site. Various donor regions are mentioned in literature (3-7). With the possibility of microsurgical tissue transfer not only the restoration of the natural face contour, but also the reconstruction of a functioning "chewing organ" becomes mandatory. Usually the reconstruction of the maxilla (alveolar ridge with oral mucosa and osseointegrated implants) is performed in several surgical steps including bone transfer, subsequently establishment of a stable soft tissue coverage, placement of osseointegrated implants and further preprosthetic surgery (8,9,10). These stepwise procedures have certain disadvantages and are connected with severe mental stress for the patients, who in course of several interventions are frequently confronted with unsatisfying success, intraoral bulky soft tissue mass, risk of infection and partial loss of the reconstructed structures around the implants. In comparison to the stepwise method, the vascularized combined flap, prefabricated somewhere else on the body, offers several advantages. With this concept only one instead of several surgical procedures in the face is necessary, since all anatomical and functional aspects have already been considered. The above mentioned discomfort for the patient is reduced and the construction of a combined soft tissue and bony flap with dental implants is performed in a sterile, not contaminated region. The lining of the prefabricated flap imitates the oral mucosa and is suitable as a stable periimplantory soft tissue condition. The implants already at the donor site stably osseointegrated are suitable for flap fixation after flap transfer into the maxillary defect.

The precise preplanning of prefabrication is possible by the use of a real time three-dimensional CT visualisation determining the size and special form of the transplant and the correct position of the implants (11,12,13).

In our described concept the lateral border of the scapula has been selected for the maxillary alveolar ridge reconstruction since the dimension of the lateral border of the scapula imitates the maxillary alveolus and palate (14,15). The height and width of the lateral border of the scapula differs a lot and in previously published investigations 10 % of the scapula have inadequate values at three levels (16). Therefore precise preoperative 3-dimensional analysis of the placement of the implant is mandatory.

2. Methods

The following procedure has been performed in 4 clinical cases. The preoperative diagnosis was visualised with three-dimensional reconstruction (Voxel Flinger ARRI high speed image operation system with complete interactive 2D and 3D possibilities of visualisation and manipulation) of CT data (HIQ Siemens thickness of slices 1-2 mm, reconstructed in high resolution mode). The system provides - after saving the sections from the CT or MR device - manifold interactive image manipulations via graphic work station and appropriate software. With this system the bony defect in the face and the appropriate place of the lateral border of the scapula can be correlated. In two clinical cases stereolithographic models (Laserform) of both the maxilla and the scapula were performed for additional preoperative planning and the preparation of the osteosynthesis material.

In each case a cephalometry X-ray analysis program (GAMMA-CADIAS) was used and relevant gnathological parameters were transferred to 3D CT visualisation via graphic work station.

In all cases the surgical procedure was performed in two stages. In the first stage the combined scapula bony flap was prefabricated.

According to the preoperative analysis the appropriate part of the lateral border of the scapula was selected, the vascular bundle to the scapula in a distance of 2-3 cm dissected and the implants (Branemark, Bone Lock- Leibinger) placed into position according to the preoperative planning. Now the selected piece was freed from almost all attached tissues and osteotomized in the selected dimension. This bony piece, being in connection only with the vascular bundle of the circumflex scapula vessels, was covered with split skin grafts and encapsulated with Goretex 1 mm sheets. Muscles, subcutaneous tissue and skin was closed in layers and the prepared flap left in this position for 3 months.

After this period the implants are osseointegrated. The split skin attached to the bone has changed to a mucosa-like stable structure. Now the microsurgical transfer of the flap into the face was performed. Simultaneously the surgical procedure in the maxillofacial region and the harvesting of the prefabricated scapula flap together with its vascular pedicle, if necessary in combination with other flaps as demonstrated below, were performed by two teams. The Goretex membrane was removed, and the flap transferred into the face. The flap was fixed according to the individual situation with miniplates and metal bars. When metal bars were used they were attached and fixed with methacrylate to the osseointegrated implants of the flap and teeth or previously placed implants in the remaining structure of the maxilla. Venous grafts have been used to anastomose the vessel of the flap with the facial vessels and the iugularis vein (Fig.1). The dental rehabilitation was performed several weeks later.

3. Clinical cases

Case 1

A 58 years old female patient was left with a hemimaxillectomy following resection of a protruding meningeoma of the skull 13 years ago (Fig 2).

The appropriate part of the scapula for placement of implants is selected with interactive 3D-imaging manipulation of CT data (Fig.3) and the prefabrication was performed in the described manner (Fig.4). Three months later the prefabricated flap was harvested, the Goretex membrane removed (Fig. 5) and transferred to the face. One artery and 2 veins are anastomosed to the Arteria and Vena facialis and iugularis on the left side of the face with interposition of two vein grafts. The bone fixation is achieved with abutments and metal bars fixed to the implants of contralateral remaining maxilla with methacrylate as described above (Fig. 6). Three months later the dental rehabilitation was completed. The split skin cover of the scapula flap imitates the oral mucosa and functions excellently as a stable implantory soft tissue (Fig.7). The bridgework on the implants in the flap region on the left side and the implant fixed and the mucosa- supported prosthesis on the intact right side are demonstrated in Fig. 7. The precise fitting of the transferred flap was controlled by 3D CT scans postoperatively (Fig.8).

Case 2

A 17- years old male patient with a remnant gap of the maxilla following several surgical interventions to correct a bilateral lip, alveolar and palate cleft in early childhood (Fig.9). The 3D CT visualisation and splint cast model demonstrates the lyra- shape and gap of the alveolar ridge (Fig.10). In order to correct the malocclusion (Fig. 11) the dental arch of the maxilla was forced expanded (Fig.12), and the mandibula was retropositioned by double segmental osteotomy (Fig. 13). A combined scapula flap was prefabricated and transferred to the face in a similar manner as in case 1 three months later (Fig.13). The postoperative results 6 months later after the dentition was completed is demonstrated in Figs. 14-17.

Case 3

A 24- years old male patient with a similar maxillary defect as in case 2 suffers from a remaining defect of the maxilla as a result of a bilateral cleft lip and palate. The same procedure as in case 2 was performed but failed on the 7th postoperative day due to thrombosis of the anastomosed vessels. One year later the same procedure with prefabrication and secondary transfer to the face was successful.

Case 4

Case 4: 27 year old male patient with loss of the right maxilla, the right cygoma including orbital floor, the soft tissue of the cheek and the right side of the nose, following radiotherapy of a maxillary tumor 5 years before (Fig.18a,18b). The reconstruction was successfully performed with a prefabricated scapula flap for the alveolus and hard palate. Attached to thr prefabricated flap and nurished by the same vascular pedicle a second scapula bone flap together with the teres major muscle was transfered to reconstruct the corpus maxillae and apertura piriformis.The missing soft tissue of the right cheek area was replaced by a scapula skin flap, being transplanted together with the two bone flaps depending on the same single vascular pedicle (Fig.19a, 19b). The reconstruction was planned by use of a stereolithographic model (Fig. 20a, 20b). The prefabrication of one scapular bone flap was performed in the usual manner. A nonvascularized bony piece of the scapula was used for nose reconstruction (Fig. 21). The reconstruction was fully successful, every transplanted vascularized tissue healed without complication, and the patient 4 months later is demonstrated in Fig 22.

4. Results

Two patients had a defect of the frontal maxilla as a remnant of a congenital bilateral cleft lip and palate. Both patients had been surgically treated several times during childhood. The third patient had a missing left cygoma and maxilla following resection of a protruding meningeoma through the base of the skull. The fourth patient had lost the whole right maxilla including the orbital floor together with the cygoma, the lateral wall of the nose, the apertura piriformis, the septum of the nose and the alveolus in the entire frontal region including the contralateral side. In all cases a preplanning with three-dimensional imaging and in the two latter tumor resection cases a laser stereolithographic acrylic model was produced. In all four cases the lateral border of the scapula was used as a combined prefabricated flap with a split skin graft attached to the bone and osseointegrated implants in place. Only one major complication in this series had to be accepted because one flap was lost due to thrombosis of the anastomosed vessels. In a second intervention one year later the contralateral scapula flap was used successfully for the same purpose. The split skin graft placed directly onto bony flap changed to a sort of oral pseudomucosa which hardly can be distinguished from the surrounding real mucosa. In all cases the transplanted bone healed nicely, and since then in two cases the full dental rehabilitation had taken place. Secondary procedures for flap fittening, debulking of soft tissues and preprosthetic surgery were not necessary. Donor site complications occurred in one case, with a temporary axillary nerve palsy. Follow up was from three to twenty-four months; no loss of any dental implants had to be accepted up to now. Only minimal bone resorption and no periimplantory infection was determined.

5. Discussion

The purpose of the described procedure of reconstruction is the restoration of aesthetic contour of the face and oral function. In order to increase the precision of our reconstructive interventions all relevant factors have to be included into planning of surgery since anatomic and functional necessities are exactly defined in advance. Up to now, a stepwise reconstruction of the maxillary contour and dental rehabilitation in the facial region has been favoured by many authors, and the achievement of several goals with a prefabricated flap seemed to be technically not feasible (8,17,18).

Our conception of creating a stable thin layer of soft tissue coverage already in a donor region prevents a bulky intraoral mass that impairs oral function. In comparison to dermal and jejunum flaps this created "neogingiva" is less susceptible to infections around the implant. In conventional surgical methods periimplantic inflammations appear nearly always in the form of long-lasting chronic proliferative granulations and/ or abscesses often leading to loss of implants and resorption of the skeletal transplant.

The advantages of placing the implants into the bony flap during the prefabrication procedure is the sterile surrounding in the shoulder region enhancing the osseointegration of the implants and an optimal contact with the surrounding "neomucosa". To make a prefabricated combined flap including osseointegrated implants possible, planning has to be carried out not only by conventional radiological methods and cephalometric analysis but also by the use of modern radiodiagnostic procedures. Comprehensive preoperative planning is possible by means of three- dimensional imaging and interactive manipulation of CT data since only by this method a relation between donor region and the region to be reconstructed can be established. Moreover, the production of organ models (stereolithography) allows the planning with a touchable object that can be manipulated. Thus, the size and shape of the flap, the height and shape of the alveolar process, the shape of the palatal vault and the dental arch as well as the anatomic structure in the surrounding area can be designed. In addition, cephalometric planning of the correct position of the maxilla and the determination of functional aspects of chewing by functional analysis are highly essential.

With this demonstrated concept parts of the alveolar ridge, in exceptional cases of congenital clefts can be successfully reconstructed and the contour of the face together with the dental rehabilitation improved. In selected cases the prefabricated scapula flap can be combined with additional revascularized neighboured tissue structures, as demonstrated in the last case. The goretex membrane around the prefabricated bony flaps seems to be important to separate the bony structures from ingrowing connective tissues and fascilitates the harvesting of the flap during second stage operation.

The demonstrated concept of 3D-CT guided flap prefabrication and secondary microsurgical transfer to the maxillary defects to be reconstructed including osseointegrated implants proved to be very successful in 4 cases and can be recommended.

6. References

1. Taylor GI.:
   Reconstruction of the mandible with free composite iliac bone grafts. Ann. Plast. Surg. 9, 362, 1982
2. Varemchuk MJ.:
   Vascularized bone grafts for maxillofacial reconstruction. Clin. Plast. Surg. 16, 29, 1989
3. Boyd JB, Rosen I, Rotstein L, Freeman JG, Manktelow R, Zuker R.:
   The iliac crest and the radial forearm flap in vascularized oromandibular reconstruction. Am. J. Surg. 159, 301, 1990
4. Daniel RK.:
   Mandibular reconstruction with free tissue transfers. Ann. Plast. Surg. 1, 346, 1978
5. Flemming AFS, Brough MD, Evans ND, Grant HR, Harris M, James DR, Lawlor M, Laws IM.:
   Mandibular reconstruction using vascularised fibula. Br. J. Plast. Surg. 43, 403, 1990
6. Hidalgo DA.:
   Aesthetic improvements in free-flap mandible reconstruction. Plast. Reconstr. Surg. 88, 574, 1991
7. Swartz WM, Banis JC, Newton ED, Ramasastry SS, Jones NF, Acland R.:
   The osteocutaneous scapular flap for mandibular and maxillary reconstruction. Plast. Reconstr. Surg. 77, 530, 1986
8. Reuther JF.:
   Die chirurgische Therapie der Karzinome im Bereich der kaudalen Mundhöhle. K. Vinzenz, HW. Waclawiczek eds. Die chirurgische Therapie von Kopf- Halstumoren. Wien New York, Springer Verlag, 57-76, 1992
9. Eriksson E, Branemark PI.:
   Osseointegration from the perspective of the plastic surgeon. Plast. Reconstr. Surg. 93/3, 626, 1994
10. Neukam FW.:
    Functional and esthetic rehabilitation with Branemark implants following oncologic surgery. T Albrektsson, GA Zarb eds., The Branemark osseointegrated implant. Chicago, Quintessence, 1989b
11. Altobelli DE, Kikinis R, Mulliken JB, Cline H, Lorensen W, Jolesz F.: Computer assisted three-dimensional planning in craniofacial surgery. Plast. Reconstr. Surg. 92/4, 576, 1993
12. Elliott HR, Norris MS, Rosen JM.:
    Application of high tech three dimensional imaging and computer generated models in complex facial reconstructions with vascularised bone grafts. Plast. Reconstr. Surg. 91/2, 252,
13. Andersson JE.:
    CT-scanning in the preoperative planning of osseointegrated implants in the maxilla. Int. J. Oral Maxillofac. Surg. 17, 33, 1988
14. Gilbert A, Teot L.:
    The free scapular flap. Plast. Reconstr. Surg. 69, 601, 1982
15. Dos Santos LF.:
    The vascular anatomy and dissection of the free scapular flap. Plast. Reconstr. Surg. 73, 599, 1984
16. Frodel JL, Funk GF, Capper DT, Fridrich KL, Blumer JR, Haller JR, Hoffman HT.:
    Osseointegrated implants: A comparative study of bone thickness in vascularised bone flaps. Plast. Reconstr. Surg. 93/3, 449, 1993
17. Riediger D.:
    Restoration of masticatory function by microsurgically vascularised iliac crest bone grafts using enosseous implants. Plast. Reconstr. Surg. 81, 861, 1988
18. Betz TH, Reuther JF, Steveling H, Renk A, Buttler E.:
    Orale Rehabilitation mit Hilfe von Dentalimplantaten nach Verlust des Alveolarfortsatzes.Z. Stomatologie 90/9, 489, 1993

7. Legends to figures

Pictures are available on request kurt.vinzenz@vienna.at