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28

Indications and Technical Considerations of Different Fibula Grafts

Peter Stoll

Bridging osteosynthesis using reconstruction plates represents only one step in the patient’s rehabilitation following continuity resection of the mandible. The low perioperative morbidity rate is overshadowed by a high long-term morbidity rate.1–6 In addition, functional outcome is relatively poor in many cases.

Bone resorption underneath the plate, loosening of screws, plate fractures, and hardware extrusion frequently occur.6 For the patients’ comfort and to avoid long-term hardware complications, primary or secondary reconstruction using freetissue or microanastomosed vascularized bone grafts is therefore desirable.

The choice of the grafts depends on the following:

1.The size of the bony defect

2.The amount of resected soft tissue

3.Radiation therapy considerations

Full rehabilitation, however, is achieved only after the reestablishment of masticatory function with osseointegrated dental implants and prosthetic suprastructures.7–9 Therefore, the bone grafts should also be suitable for this purpose.

Avascular bone grafts for the reconstruction of mandibular continuity defects demonstrate a high failure rate when they are placed in an unstable surrounding environment. Creeping substitution through neovascularization is impossible without stable fixation of the bone graft to the remaining bone segments. This is in contrast to vascularized bone grafts, which will often survive even under unstable conditions, as long as their vascular pedicle is intact. However, malunion, nonunion, or even displacement of the bone graft can greatly limit a patient’s masticatory rehabilitation and overall postoperative outcome.

Nevertheless, the use of free cancellous hip bone is still a valuable technique in the treatment of most minor defects. The bone graft height and width can be shaped to the remaining bone segments. Overcorrection with excess bone is often helpful, as nonvascularized bone grafts have a higher resorption rate.10,11

Cases exhibiting a compromised recipient site owing to pre-

vious radiation therapy or when additional radiation therapy is planned usually should be excluded from transplantation of avascular grafts (even for small bony defects).

Since microanastomosed bone grafts consist of living tissue, they are capable of independent survival within a compromised recipient site. Furthermore, vascularized grafts are able to improve the local wound regenerative situation12,13 and should therefore be considered more suitable than avascular grafts.

In strictly osseous defects, vascularized fibula grafts present numerous advantages. Their bony architecture is similar to that of the mandible, unlike iliac crest or scapula, and they are capable of restoring defects up to a length of 25 cm. The grafts can be easily adjusted to the curvature of the mandible using the intersection technique (Figure 28.1). They are associated with very low postoperative donor site morbidity and facilitate the insertion of dental implants owing to fibular similarity to mandibular width and marble-like bone structure14,15 (Figure 28.2). Since vascularized grafts behave like an edentulous mandible, osseointegration can generally be expected9 (Figure 28.3).

Owing to their shape, fibula grafts are better suited to the insertion of dental implants than scapula or hip bone. Scapula also seems to be limited as far as length and diameter is concerned. Frequently, especially in females, the insertion of dental implants is not even possible.16–18

In this context, it is important to note that the harvesting of fibula grafts can be performed using a two-team approach. This procedure saves considerable operating time. The harvest of scapula grafts requires lateral positioning of the intubated patient, which prevents simultaneous surgery by a second team.

Since the skin paddle of the fibula is relatively thin and sometimes exhibits limited reliability,19 use of the fibula osteocutaneous flap is indicated in cases with smaller soft tissue defects. For large defects it is better to use the supramalleolar skin paddle20 together with the fibula. This is owing to a relatively long vascular pedicle, which allows the application of a reconstruction plate for fixation of the bone graft.

327

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FIGURE 28.1 Single strut fibula graft sawed into three sections with adherent soft tissue prepared for microvascular anastomosis.

The main disadvantage of conventional fibula grafts is their limited height. This especially causes problems in dentate patients, in whom the residual bone segments are normal size. The use of a single strut fibula bone graft with its height of approximately 1.5 cm produces a considerable step between the graft and residual bone segment (Figure 28.4).

Recently interest in the placement of osseointegrated implants into these bone grafts to facilitate improved functional dental rehabilitation has grown dramatically. Although enormous efforts have been made concerning the osseointegration of dental implants in bone grafts, the placement of an adequate prosthesis and return to function have fallen short of ideal goals.8,21 This is often owing to scarred intraoral tissues, induration, loss of vestibule, altered muscle function, loss of

P. Stoll

FIGURE 28.3 Radiograph demonstrating osseointegration of ITI-den- tal-implants (Bonefit®, ITI Strauman, Waldenberg, Switzerland) in a vascularized fibula graft.

sensation, mucosal changes from irradiation,22 and last but not least limited compliance.

In addition to other surgical measures (i.e., vestibuloplasty), prosthetic rehabilitation and fabrication of an acceptable denture may be improved by enlarging graft height. By reducing the distance between the upper rim of the graft and the occlusal plane the vertical dimension of the dental suprastructure can be reduced, and the reverse. Thus unfavorable forces upon buttressing teeth or dental implants caused by long lever arms can be avoided.

FIGURE 28.2 Cross section of the fibula with a marble-like bone structure of the thick compact layer giving an excellent anchorage for dental implants (left). Diameter-reduced ITI-dental implant (Bonefit®, ITI Strauman, Waldenberg, Switzerland) 8 mm in length (right).

FIGURE 28.4 Radiograph demonstrating a considerable step between the remaining dentate mandible (right) and the fibula bone graft (left).

28. Indications and Technical Considerations of Different Fibula Grafts

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FIGURE 28.5 Lateral access to the fibula after separation of the crural fascia, the long lateral peroneous muscle, and the soleus muscle.

Owing to its extensive periosteal vascular network, the diaphysis of the fibula can be transversally osteotomized into different segments without danger of necrosis (Figure 28.1).11 The principle of setting one fibular segment beside the other was primarily used for reconstruction of the tibia.23,24 This reinforced “double barrel” served as a strong buttress.

In 1994, Bähr et al.25 were the first to introduce this method for the repair of mandibular defects.

After angiographic imaging of the tibial and peroneal vessels, the fibula is dissected by using a lateral approach (Figure 28.5).26 At first, the crural facia is separated and then the fibula is degloved between the long lateral peroneal muscle

a

b

FIGURE 28.6 The diaphysis of the fibula is osteotomized proximally and distally. The size of the graft has to be taken double as long as the mandibular defect.

and the soleus muscle. The diaphysis is osteotomized proximally and distally so that the removed bone segment is at least twice as long as the resected section of the mandible (Figure 28.6). Then the vascular pedicle, which is maintained for as long as possible, is severed and the graft is divided into sections. The intersection technique can also be used when the bone graft is still connected to its original blood supply.

Cases exhibiting a straight mandibular bony defect (i.e., the horizontal ramus) require only one osteotomy to obtain two equal pieces. One of the two pieces is now rotated 180° and is laid on the other (Figure 28.7).

Cases with arched mandibular defects (i.e., comprising the

FIGURE 28.7 (a,b) Double barrel for straight mandibular defects. After cutting the bone graft into two equal pieces without damaging the vascular pedicle, one of the two pieces is rotated 180° and placed over the other.

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P. Stoll

a

b

FIGURE 28.8 (a,b) Double barrel for arched mandibular defects. The fibula is already cut into four pieces. Two are rotated 180° and placed over the other two, respectively. The curvature is maintained by us-

ing a miniplate. The bone graft is still in connection with its original vascular supply.

a

b

FIGURE 28.9 (a,b) Insertion and fixation of a fibula double barrel into a straight mandibular defect.

28. Indications and Technical Considerations of Different Fibula Grafts

331

horizontal ramus and the anterior part) require three intersections to gain four pieces of bone. Following the same procedure as described earlier, two of the bone pieces are now rotated 180° and laid upon the other two. Thus the graft can later be adjusted to the mandibular curvature. Adaptation of the graft segments can be accomplished by using miniosteosynthesis plates (Figure 28.8).

It is mandatory that during this procedure the peroneal vessels must not be compromised. The original dorsal surfaces of the bone graft are now put together, with the peroneal vessels in a lateral position.

The artery and the two accompanying veins of the vascular pedicle of the graft are now anastomosed at the recipient site. Since this vascular pedicle is relatively long (6 to 8 cm) and the diameter of the vessels relatively large (1.5 to 4

mm),27,28 the anastomosis can be accomplished with a high margin of safety.

Finally the fibula double-barrel bone graft is inserted into the resection defect, which was maintained by using a reconstruction plate (Figures 28.9 and 28.10). The reconstruction plate ensures, during the postoperative period, stable fixation of the remaining bone stumps under function in either primary or secondary vascular bone repair. This procedure seems to protect the anastomoses and promote uneventful healing. Loosening of plates and screws, pseudoarthrosis and infection, which can occur using functionally unstable fixation devices (i.e., miniplates), are unusual.

If necessary, final adjustment of the graft by shortening or sloping of the ends can be easily performed. The lower part of the double barrel is now rigidly fixed to the reconstruction

a

b

FIGURE 28.10 (a,b) Insertion and fixation of a fibula “double barrel” into an anterolateral mandibular defect.

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P. Stoll

FIGURE 28.11 Positive technetium scintigraphy 3 days after mandibular bone repair using a fibula double-barrel vascularized graft.

a

b

FIGURE 28.12 (a) X-ray showing the double-barrel fibula bone graft prior to removal of the reconstruction plate. (b) Three-dimensional CT scan showing the double-barrel fibula bone graft after the re-

moval of the reconstruction plate. The height of the bone graft is approximately the same as the neighboring mandible.

28. Indications and Technical Considerations of Different Fibula Grafts

333

plate using metal screws. It should be emphasized that these lag screws are not load-bearing, but serve only to hold the graft in position between the rigidly fixed mandibular segments. Gaps between the bone graft and the remnant, if any, are filled with bone dust, bone wedges, or both.

Black ink injections in human cadavers23 and intraoperative findings have demonstrated that the perfusion of fibula struts is maintained despite the 180° rotation of one bone strut.

Postoperatively, the vascular anastomosis is checked by conventional Doppler sonography and technetium scintigraphy (Figure 28.11). Blood flow and immediate accumulation of the radionucleotide can be registered if the vessels are patent.

In the case of a nonvascularized bone graft, accumulation of technetium owing to vascular invasion29 can be detected only after the 11th postoperative day.

Because the periosteum and the vascular periosteal network must not be stripped to preserve the blood supply of the graft, the two bone struts interface only with the residual bone segments and not with each other. Functionally, this is not important because bony consolidation between the segments and the double barrel is sufficient. The height of the bone graft is equal to that of the adjacent mandible (Figure 28.12).

Six months after vascular bone repair, the reconstruction plate is removed. The bone graft is now ready for insertion of dental implants (Figure 28.13).

At our institution we have abandoned simultaneous dental implant placement during bone repair for two reasons. The first is possible impairment of the graft’s blood supply, and

FIGURE 28.13 Insertion of two ITI dental implants (Bonefit®, ITI Strauman, Waldenberg, Switzerland) 6 months after bone repair.

FIGURE 28.14 Fixed bridgework attached to two ITI dental implants (Bonefit®, ITI Strauman, Waldenberg, Switzerland) 3 months after insertion.

the second is inability to control correct implant position during placement and adaptation of the graft.

Three months after insertion of endosseus dental implants, the prosthetic suprastructure can be fabricated (Figure 28.14).

References

1.Komisar A, Warman S, Danziger E. A critical analysis of immediate and delayed mandible reconstruction using AO-plates.

Arch Otolaryngol Head Neck Surg. 1989;115:830.

2.Davidson J, Birt WD, Gruss J. AO-plate mandibular reconstruction: a complication critique. J Otolaryngol. 1991;20:104.

3.Freitag V, Hell B, Fischer H. Experience with AO-reconstruc- tion plates after partial mandibular resection involving its continuity. J Craniomaxillofac Surg. 1991;19:191.

4.Schusterman MA, Reece GP, Kroll SS, Weldon MA. Use of the AO-plate for immediate mandibular reconstruction in cancer patients. Plast Reconstr Surg. 1991;88:588.

5.Kim MR, Donoff RB. Critical analysis of mandibular reconstruction using AO-reconstruction plates. J Oral Maxillofac Surg. 1992;50:1152.

6.Wächter R, Stoll P. Komplikationen nach primärer Unterkieferrekonstruktion mit THORP-Platten. In: Neumann H-J, Hrsg.

Ästhetische und plastisch-rekonstruktive Gesichtschirurgie. Rheinbek: Einhorn-Presseverlag; 1993:259.

7.Wächter R, Diz Dios P. Zur oralen funktion von tumorpatienten nach operation und versorgung mit Bonefit-implantaten. Erste qualitative und quantitative ergebnisse. Z. Zahnärztl Implantol. 1993;9:134.

8.Wächter R, Stoll P, Schilli W. Possibilities and limits of endosteal implants for the oral rehabilitation of tumor patients after radiotherapy. 5th International Congress On Preprosthetic Surgery, Vienna. April 15–18, 1993.

9.Wächter R, Stoll P, Bähr W, Lauer G. Osseointegration of ITIdental implants (Bonefit) in non-vascularized and vascularized mandibular bone grafts. Proceedings 1st World Congress of Osseointegration, Venice. Sept. 29–Oct. 2, 1994.

10.Riediger D. Restoration of masticatory function by microsurgically revascularized iliac crest bone grafts using enosseous implants. Plast Reconstr Surg. 1988;81:861.

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11.Hidalgo DA. Fibula free flap: a new method of mandible reconstruction. Plast Reconstr Surg. 1989;84:71.

12.Duncan MJ, Manktelow RT, Zucker RM, Rosen IB. Mandibular reconstruction in the radiated patient: the role of osteocutaneous free tissue transfer. Plast Reconstr Surg. 1985;76:829.

13.Ioannides C, Fossion E, Boeckx W, Herrmans B, Jacobs D. Surgicalmanagementoftheosteoradionecroticmandiblewithfreevascularized composite flaps. J Craniomaxillofac Surg. 1994;22:330.

14.Urken ML. Composite free flaps in oromandibular reconstruction. Review of the literature. Arch Otolaryngol Head Neck Surg. 1991;117:724.

15.Huryn JM, Zlotolow JM, Piro JD, Lenchewski E. Osseointegrated implants in microvascular fibula free flap reconstructed mandibles. J Prosthet Dent. 1993;70:443.

16.Serra JM, Paloma V, Mesa F, Ballesteros A. The vascularized fibula graft in mandibular reconstruction. J Oral Maxillofac Surg. 1991;49:244.

17.Frodel JL, Funk GF, Capper DT, Fridrich KL, Blumer JR, Haller JR, et al. Osseointegrated implants: a comparative study of bone thickness in 4 vascularized bone flaps. Plast Reconstr Surg. 1993;92:449.

18.Bekiscz O, Adant J, Denoel C, Lahaye T. Mandibular reconstruction. An anatomical study of bone thickness in three donor sites. Proceedings from the 12th Congress of the European Association for Cranio-Maxillofacial Surgery, The Hague, Sept 5th–10th, 1994.

19.Schusterman MA, Reece GP, Miller MJ, Harris S. The osteocutaneous free fibula flap. Is the skin paddle reliable? Plast Reconstr Surg. 1992;90:787.

P. Stoll

20.Wolff K, Herzog K, Ervens J, Hoffmeister B. Experiences with the osteoseptocutaneous fibula-flap. 12th Congress of the European Association for Cranio-Maxillofacial Surgery, The Hague, Sept. 5th–10th, 1994.

21.Bundgaard T, Tandrup O, Elbrond O. A functional evaluation of patients treated for oral cancer. A prospective study. Int J Oral Maxillofac Surg. 1993;23:28.

22.Lukash FN, Sacks SA. Functional mandibular reconstruction. Prevention of the oral invalid. Plast Reconstr Surg. 1989;84:227.

23.Jones MF, Swartz WM, Mears DC, Jupitter JB, Grossman A. The “double barrel” free vascularized bone graft. Plast Reconstr Surg. 1988;81:379.

24.O’Brian B, Gumley GJ, Dooley BJ, Pribaz JJ. Folded free vascularized fibula transfer. Plast Reconstr Surg. 1988;82:311.

25.Bähr W, Stoll P, Wächter R. “Fibula Doppeltransplantat” als gefäßgestielter Unterkieferersatz. Dtsch Z Mund-Kiefer- Gesichtschir. 1994;18:219.

26.Gilbert A. Vascularized transfer of the fibula shaft. Int J Microsurg. 1979;1:100.

27.Manktelow RT. Mikrovaskuläre Wiederherstellungschirurgie. Anatomie, Anwendung und chirurgische Technik. Berlin: Springer Verlag; 1988.

28.Wood MB. Atlas of Reconstructive Surgery. Rockville, MD: Aspen; 1990.

29.Berggren A, Weiland A, Östrup L. Bone scintigraphy in evaluating the viability of composite bone grafts revascularized by microvascular anastomoses, conventional autogenous bone grafts, and free non-vascularized periosteal grafts. J Bone Joint Surg Am. 1982;64:799.