Scand J Plast Reconstr Surg 9: 116-128, 1975

RECONSTRUCTION OF THE DEFECTIVE MANDIBLE

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P.-I. Brhemark, J. Lindstrom, 0. Hallh, U. Breine, P.-H. Jeppson and A. ohman From the Laboratory of Experimental Biology (Head: P.-I. Brdnemark), subdivision of the Department of Anatomy, the Departments of Otorhinolaryngology (Head: G. Herberts), Plastic Surgery (Head: B. Johanson), and Oral Diagnosis (Head: A. ohman), University of Griteborg, and the Department of Otorhinolaryngology (Head: P. H. Jeppson), Molndal Hospital, M6lnda1, Sweden

(Submitted for publication December 9, 1974)

Abstract. In a clinical material consisting of 3 1 cases of mandibular defects, caused by tumour resection or by trauma, reconstruction has been carried out by means of a stabilizing titanium splint and autologous hone and marrow transplantation, the longest period of observation being 9 years. The functional results obtained are assessed with reference to the cause of resection. Different technical procedures are described and the objectives and the planning of reconstruction of the lower jaw are discussed.

Loss of a segment of the lower jaw as a result of trauma or surgery results in impairment of the functions of chewing and swallowing, as well as speech difficulties. The decrease in function varies, in kind and degree, with the size and location of the defect. Inadequate oral anatomic conditions can also have a negative effect on the patient’s respiratory capacity. Sometimes psychic insufficiency reactions can be due to defects of the jaw and the functional and cosmetic problems involved. The radical surgery which is often applied in treating malignant and semi-malignant tumours of the soft and hard tissues of the oral region results in mandibular defects. The patient’s rehabilitation should be taken into consideration already in the planning of mandibular resection. It is generally agreed that primary reconstruction, aiming at full restitution, should be performed in cases of benign tumours. In cases of malignant tumours, on the other hand, primary reconstruction attempts should be limited to establishing continuity of the mandible, full reconstruction being postponed to a later stage, Supported by grants from the Swedish Cancer Society, Goteborgs Lakarsallskap and Trygg-Hansa’s Eightieth Anniversary Foundation. Scand J Plast Reconstr Surg 9

when a long-term prognosis has been established (Conley, 1953). The clinical problems connected with defects of the mandible have been rather extensively dealt with in the literature, both with regard to the functional problems involved and to principles of treatment and the result of reconstructive procedures (Ivy & Epes, 1927; Cook, 1968; Redpath, 1970; Singleton, 1970; Nahum & Boyne, 1972). In this context it seems pertinent also to mention some reports on long-term follow-ups of successfully reconstructed defective mandibles. Thus Robinson (1959) reports on a case involving 51 years of good function of a silver implant, substituting for the right half of the mandible of a patient originally operated on at 11 years of age. Ivy & Eby (1958) report on three cases of mandibular defects, treated 38 and 39 years earlier with autologous whole bone grafts from the iliac bone, resulting in good restitution of function and incorporation of the graft. These authors also make a valid comment on how to handle these often technically complicated cases. They emphasize “the extreme importance, in order to achieve the best results, of close collaboration of the surgeon with a dental colleague who has a profound understanding of the problems of fixation and dental restoration involved”. Artificial substitutes for mandibular defects can sometimes be tolerated by the tissue, but bone does not regenerate into these materials. Furthermore, the band between the mandible and the substitute material tends to break, probably as a result of the constant movement of the whole area (Alonso & Bailey, 1972).

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Reconstruction of defective mandible 117

Autologous rib transplants for bridging mandibular defects have the proper anatomy for defects in which the mental region is involved (Conley; de Champlain, 1973). Satisfactory cosmetic and iFunctional results are nevertheless difficult to achieve with this type of graft. During the last few decades different reconstruction methods for bone defects have been developed (for review see e.g. Albrektsson, 1971; Adell, 1974). Grafts consisting of autogenic bone with viable marrow have a great osteogenic capacity (Burwell, 1969; Albrektsson) and have, consequently, been used in oral reconstructive surgery (Boyne, 1969; 1973). Mowlem (1944) describedamethod for obtaining autologous grafts consisting of marrow and trabecular bone from the crest of the iliac bone. Reports in the literature suggest that reconstruction using cancellous bone from the ilium is the method which gives the best long-term results (Alonso & Bailey). Even if the period of intermaxillary fixation is long (8-12 weeks) the transplant and the ends of the remaining mandible must also be stabilized by a mechanical device. This may consist of a metallic net, e.g. vitallium, tantalum, but even nonmetallic materials of nylon or silastic have been used. The latter are considered easier to mould during the operation (Leake & Rappaport, 1972). A variety of technical approaches to the problem of mandibular reconstruction have been reported in the literature. Most of them are concerned with modifications of the splint used for establishing continuity by connecting the two remaining mandibular fragments (Clarke, 1966; Cook; Snell & Dott, 1969; Hahn & Corgill, 1969; Bowerman & Conroy, 1969; Fordyce, 1970; Huebsch, 1970; Manchester, 1972; Michelet, Deymes & Dessus, 1973). In addition to these technical developments, studies have also been performed with regard to biomechanical problems related to factors of relevance to the incorporation of, in particular, metallic appliances in bone tissue (Heiss & Grasser, 1968; Southam & Selwyn, 1970; Cameron, Pilliar & Macnab, 1973; Uhthoff, 1973; Hughes & Jordan, 1974). The importance of satisfactory fixation and immobilization during healing has been especially emphasized. Intermaxillary fixation, cap-splints or extraoral fixation can be used, depending on the number and position of the remaining teeth, if any. In assessing the results of various reconstruction procedures, more account should be taken of the

functional result than of the skeletal continuity as revealed by X-ray pictures. Anlyan & Manis (1968) published results from 17 patients, in whom primary reconstruction after mandibular resection had been carried out after tumour surgery. The defect in the jaw bone was filled with autologous graft material in the form of bone chips. Nine patients showed functional stability at clinical examination. However, this could not be confirmed by X-ray as bone union. In 6 cases resorption followed. The authors conclude that an osseofibrous connection can be sufficient to establish the required functional stability of the mandible. The problems arising from fixation of a stabilizing splint to the ends of the mandible have been discussed by de Champlain. The angulus area is considered to be especially prone to poor fixation, regardless of whether cerclage or metal plates are used. This is a result of the muscular tension affecting the proximal mandibular fragment. De Champlain suggests that for this reason the proximal fragment should not be placed in a completely correct anatomical position when secondary reconstructions are carried out, but in an intermediate position. This, in turn, should result in reduced muscular tension thus minimizing the risk of mobility. The majority of reports on mandibular reconstruction comprise one or two patients in whom the autogenous transplant has become resorbed, for unknown reasons. Nahum & Boyne suggest that the problem can be avoided by coating the inside of the vitallium form with a Micropore filter, the object of which is to permit adequate circulation while preventing connective tissue from growing into the transplant. The authors, however, have published only one case illustrating the use of this method (Boyne 1973). In an earlier paper (Brinemark, Lindstrom, Hal]en, Breine'& Hanson, 1 9 7 0 ~ )we have reported on experimental studies concerning reconstruction of defects of long bones and of the jaw in dogs by means of titanium splints and autologous bone and marrow grafts. On the basis of these experiments a method was designed for the reconstruction of defective mandibles in man. Discontinuities of the jaw caused by trauma and tumour surgery were treated by means of titanium splints in order to stabilize the fragments in correct topographical position, and by means of autologous marrowspongious bone transplants from the crest of the Scand J Plast Reronstr Surg 9

118

P . 4 Brdnemark et al.

Table l.Malignant cases. Individual defect situation. therapeutic procedure and follow-up

CASE AGE SEX DEFECT RADIATION RECONSTRUCTION

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NR .

BONE

FOLLOW UP

YEAR

TIME

METAL

1

80

prim

frame

-

l,5

extracted

-

2

80

prim

thick

-

2

intact

-

3

68

prim

thin

-

5

intact

-

4

65

prim

thin

-

5

intact

-

5

64

prim

thin

-

2

intact

-

6

61

prim

thick

-

2

intact

-

7

58

prim

thick

-

2

intact

-

8

52

prim

thin

-

1.5

extracted

-

9

49

prim

thin

-

5

intact

-

10

44

prim

thick

-

1.5

extracted

11

26

prim

thick

-

1.5

extracted

12

66

prim

frome

cancell

7

intact

incorp

13

76

sec

thin

cancell

4

intact

resorb

14

50

sec

thin

cancell

1.5

f rac t

resorb

15

47

sec

thin

cancell

5

intact

incorp

16

45

sec

thin

cancell

5

fract

resorb

17

47

sec

thin

concell

4

intact

resorb

18

42

sec

frame

cancell

8

intact

incorp

19

40

5ec

f rome

cancell

7

intact

resorb

20

58

WC

f rame

cancell

2

intact

incorp

iliac bone in order to fill the defect. The results obtained were so promising that we decided to develop the method further for different types of defects, our purpose being to simplify the surgical-technical procedure, to investigate which type of transplant was most suitable, to try to repair even defects inScand J Plast Rcconstr Surg 9

YEAR

METAL

BONE

-

-

volving the temporomandibular joint, and finally to compensate for what functional problems might remain. Our aims thus included restoration even of masticatory function by means of bone-anchored bridges. The object of this paper is to report our ex-

119

Reconstruction of defective mandible

Table 11. Benign cases. Individual defect situcztion, therapeutic procedure and follow-up

CASE AGE SEX DEFECT RADIATION RECONSTRUCTION

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NR.

YEAR

TIME

METAL

FOLLOW UP YEAR

BONE

METAL

BONE

21

66

e

prim

thin

concell

8

intact

incorp

22

37

?

prim

thin

concell

3

extracted

resorb

23

44

?

prim

frome

concell

8

intact

incorp

24

58

e

sec

thin

concell

8

intact

resorb

25

27

?

sec

frome

concell

9

intoct

incorp

26

54

6

sec

thin

whole

9

intact

incorp

Table 111. Traumatic cases. Individual defect situation, therapeutic procedure and follo w-up

CASE AGE SEX DEFECT RADIATION RECONSTRUCTION - . BONE

~

FOLLOW UP

NR.

YEAR

27

48

d

thin

-

7

intact

28

60

$

thin

cancell

7

intoct

incorp

29

40

8

thin

whola cancell

3

intoct

incorp

30

48

d

thick

whole

2

intact

incorp

31

56

8

thick

whole

1.5

intact

incorp

TIME

periences in reconstructing the jaw skeleton a.nd to suggest principles for treating mandibular defects differing in size and location.

METAL

YEAR

METAL

BONE

-

In the third group 5 cases with trnumaric defects are reported. After a lacerating injury a primary operation had been carried out at some other hospital. The patients were referred to us for secondary reconstruction (Table 111), as a rule several months after the injury.

MATERIAL The material consists of 3 1 patients who were subjected to reconstruction of defective mandibles between 1906 and 1973. The composition of the material concerning age, sex and defect location is shown in Tables I, I1 and I l l . With respect to the aetiology of the defect and the subsequent treatment, the material is divided into malignant, benign and traumatic cases. The nialignant cases (20 patients) were all sent to Sahlgrenska Sjukhuset with a diagnosis of cancer of the mouth (Table I). The therapeutic tumour program and subsequent surgery resulted in a defect of the lower jaw. Eleven out of the 20 cases received preoperative radiotherapy. Six patients were operated on for benign tumours (Table Il), diagnosed as ameloblastomas of the lower jaw. None of these cases were given radiotherapy.

METHOD During the whole period of this study the basic surgical principles have been the same. The fragments of the lower jaw on both sides of the defect (Fig. 1) have been connected to each other by a titanium splinr, secured to the bone by titanium screws.l An atraumatic technique has been employed for drilling and threading. The utmost care has been taken, by means of profuse irrigation, to avoid heat injury and, in addition, all preparation instruments have been made of titanium in order t o avoid metallic transfer (Fig. 2). The instrumental equipment for reconstruction has been manufactured by instrumentmaker V. Kuikka. Titanium fixtures of type Xenodent, AGA, have been used. Scand J Plast Reconstr Surg 9

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120 P . 4 . Brdnemark et al. Optimal functional position of the lower jaw in relation to the upper jaw has been aimed at in securing the splint to the mandibular fragments. In all cases where transplantation has been performed, autogenous graft material has been used, i n most cases marrow-spongious bone, in some cases marrowspongious bone in combination with compact bone. Only in one case has postoperative intrrmaxillary fixation been used, which means that all other patients were allowed to move their lower jaws immediately after reconstruction. As our experience increased, certain technical modifications were made. Initially, intermaxillary fixation was used during the operation in order to guarantee optimal occlusion in the reconstruction procedure. This technique, as far as primary reconstructions are concerned, has now been replaced by a method where the holes drilled for the titanium splint are completed before the mandible is cut. In secondary reconstructions, an intra-oral plastic form is used, which gives the correct positioning of the mandibular fragments during the operation. At first the titanium splint was fairly sturdy, being made individually in each particular case. During an intermediate period more delicate splints were used. In the last few cases in the series studied, a thicker J-formed splint was used (Fig. 3). In the series of malignant cases autogenous bone transplantation was carried out only in one case at primary reconstruction (case 12). In all of the other cases the object was simply to secure the position of the lower jaw by means of a titanium splint. In 12 cases primary splinting was made, in 8 cases secondary splinting and grafting. The secondary reconstructions made in cases with malignant disease were performed after a minimum of 2 years without tumour relapse. In 7 out of the 8 secondary reconstructions, marrowspongious bone was taken from the tibia or the iliac bone. In one case a composite iliac transplant consisting of marrowspongious tissue and compact bone was used. As regards benign cases, 3 primary and 3 secondary reconstructions were carried out. In all 6 cases the principle was the same, i s . the continuity of the lower jaw was restored with a titanium splint, the defect being filled with an autologous bone transplant. Special conditions prevailed in cases 24 and 26. In the first case, a woman of 58, the defect was first filled with marrowspongious bone. This was largely resorbed. At reoperation the defect was again filled with the same type of transplant. Once again resorption occurred, and in addition a skinpiercing fistula was formed. The titanium skeleton was extracted and the fistula excised. Since obviously the ordinary grafting procedures had failed in this case, we decided to use a preformed whole bone graft in order to avoid graft resorption if possible. A graft was thus preformed in the iliac bone with a titanium form, the graft containing titanium screws for fixation to the mandible and other screws for subsequent anchoring of a dental bridge. A year later this preformed graft was transplanted and fixed to the mandibular fragment. Since then (3 years' observation time) the continuity of the mandible has remained intact and a bridge has been attached to the jaw bone via the incorporated titanium screws to restore occlusal function. The other case concerns a 55-year-old man. One year after tumour surgery, a reconstruction of the larger part of the right lower jaw including the joint was made. A block of Scand J PIast Reconstr Surg 9

Fig. 1. Principles for reconstruction. ( a ) The mandibular fragments are kept in the correct anatomical position'by a titanium splint anchored by screws. (b) The bone defect is filled by an autologous bone graft.

compact and spongious bone from the iliac bone was given an adequate anatomical shape and was then connected to the distal fragment by means of a titanium splint. One year later a fistula through the skin to the titanium splint was extirpated, with subsequent uneventful healing. I n this case titanium screws for anchoring a dental bridge were installed at the grafting procedure. After the healing period a bridge was attached. The last operation was carried out some 5 years ago, and since then the patient has been free of complications and with adequate occlusal function. In the series of traumatic rases, secondary reconstruction was carried out in all patients. I n one case only reposition and fixation with a titanium splint were required. In the remaining 4 cases simultaneous bone grafting was carried out, spongious bone being used in one case and a whole bone transplant in the other three. Special conditions were at hand in rase 29, a 40-year-old man who, in an unsuccessful suicide attempt, shot himself through the back part of the lower jaw on both sides. The injury included considerable defects within the ramus and angular areas bilaterally and also large soft tissue defects. The patient was initially treated at his local hospital and later referred to us for reconstruction of the remaining defects in the lower jaw. These defects included dislocation of both temporomandibular joints, reduced range of movement, impaired occlusion, loss of both parotid glands, and bilateral paralysis of the facial nerve. The reconstruction of the mandible was performed in several stages. T o begin with, grafts were preformed in the iliac bone to substitute for the proximal mandibular regions, including the caput mandibulae. After 4 months of healing, the preformed graft for the ramus and caput of the mandible was positioned on the left side and attached, by means of incorporated titanium screws, to the remaining distal fragment. On the right side the remaining mandibular head could be placed in its functional position again and attached to the remaining distal fragment by means of a titanium splint and

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Reconstruction of defective mandible 121

Fig. 2. Instruments used for anchoring a titanium splint to the mandible.

a marrow-spongious bone transplant into the defect. At the same time the position of the mandible was corrected in relation to the upper jaw in order to achieve functional OCclusion. Immediately after operation a certain degree of movement was allowed by the use of elastic bands between the cap-splints. A functionally satisfactory result was obtained and has remained for 3 years.

Fig. 3. Examples of different types of titanium splints. (a)

First design being manufactured for individual defects. (6) The thin titanium splint which for a period was used as a stabilizer for mandibular defects with the object of distributing a certain remodelling load on the transplant during the

RESULTS In the series of cases (Table I) primary reconstruction was carried out in twelve patients. no. 12, bone was In One Of these This case was a 66-year-old woman with a right-

healing period. (c) The standardized, profiled titanium splint now routinely used in mandibular reconstruction, here shown in the main types for defects of different size and location. S c a d J Plast Reronstr Surg 9

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122 P.-I. Brhnemark et al. sided cancer of the tongue. The patient has been followed up for 7 years. The titanium splint remains intact and in position and the bone transplant has become incorporated. In the remaining 1 1 cases our object of reconstruction was simply to preserve, with the aid of the titanium splint, the continuity of the mandible and its position in relation to the upper jaw, and thus to create better conditions for prosthetic therapy, for chewing and phonation. In 7 of the 1 1 cases the titanium splint remains intact after more than 2 year’s observation. In the remaining 4 cases the splint came loose at one or more of the anchoring screws. These splints were removed within the first year after the operation. In none of these cases did the titanium splint cause any serious complications. During the period when the splint maintained a correct anatomic positioning of the mandibular fragments the defect region healed with a dense osseofibrous tissue. This gives considerably better mandibular continuity and thus improved mastication, articulation and phonation, than if no splinting had been used. In 8 cases within the series, secondary reconstructions were made more than 4 years after resection of the mandible. Simultaneous fixation of the fragments by a titanium splint and autologous transplantation with marrow-spongious bone were performed. The titanium splint remained intact in 6 cases. In 2 cases a fracture of the splint occurred when a thin and slender type of splint was used. In one of these cases the splint was removed. The other patient has had no subjective complaints or functional disturbances of the broken splint. Roentgenologically identified incorporation of the bone transplant, establishing an osseous bridge over the defect, was obtained only in 3 cases. In the remaining 5 cases resorption occurred to such a degree that the result must be considered unsatisfactory from the point of view of bone grafting, even if the functionally required mandibular continuity had been achieved. There is no obvious correlation between preoperative irradiation (2 OO& 3 000 r) and resorption of the graft. In the benign series, 3 primary and 3 secondary reconstructions were performed. In all cases fixation by means of h titanium splint was carried out simultaneously with bone transplantation. In 5 of these cases, marrow-spongious bone was used and in 1 case, whole bone. The titanium splint has remained intact in 5 cases and was extracted in one. The latter concerned a defect of the anterior aspect Scand J Plast Reconstr Surg 9

of the mandible in a patient with severe mental disease with heavy medication and with marked adiposity and low tissue vitality. After several attempts with minor surgical and technical adjustments, the splint was extracted after 2 years. For this patient a new reconstruction is in progress, a preformed graft being used. In 4 of the 6 cases the bone transplant has been incorporated satisfactorily and in 2 cases it has been resorbed. The continuity of the mandible is nevertheless functionally adequate in all 6 cases, in one of these after 8 years. The observation time in this series is long enough to permit a conclusive evaluation of the results. Cases 24 and 26 are of special interest since they represent the first cases where, in connection with whole bone transplantation, we took a further step towards full restitution. This was achieved by incorporating intraosseous titanium screws into the transplant, to function as support for a dental bridge (Brhemark, Lindstrom, H a l l h , Breine, Hanson & Ohlsson, 1969; Brinemark, 1971, 1972). In the traumatic series one case of bilateral pseudarthrosis of the mandible was treated with resection of the interposed connective tissue, the small defect being filled with a marrow-spongious bone graft, and then immobilized by means of titanium splints on both sides. After primary healing the situation has remained satisfactory for 7 years. (In this case a denture could not be worn. Intra-osseous titanium screws were used to anchor a dental bridge in order to provide full rehabilitation.) In the remaining 4 cases with larger skeletal defects, simultaneous splinting and bone transplantation were carried out. In all cases the titanium splint has remained intact and the grafted bone tissue has become incorporated. In case no. 29 there were large bilaterial defects in soft and hard tissue. In view of the original defect situation, the final result was surprisingly good, with satisfactory occlusion, an opening range of 3.5 cm, good temporo-mandibular joint function, and adequate incorporation of the transplanted bone tissue. This patient has returned to his former employment. DISCUSSION

From the literature dealing with reconstruction of mandibular defects it is clear that the clinical problems involved are of many different kinds. The material presented here, like other published

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Reconstruction of defective mandible

materials, does not provide any final solution to all the problems involved in the treatment of lowler jaw bone defects. Our experiences so far might, however, serve as a basis for some general comments. The ultimate aim in treating mandibular defects must be complete restitution and permanent consolidation of the jaw bone, adequate mobility in the temporomandibular joint, and a satisfactory functional result with respect to occlusion, mastication and phonation. With the methods now available it is only possible to obtain a satisfactory result in a limited number of cases as far as all of these goals are concerned. Radical surgery concerning cancer of the mouth often means resection of part of the mandible. In consideration of the relatively poor prognosis and the unfavourable condition of the tissue, resulting from large excisions and pre- or postoperative radiotherapy, it is not advisable to make a major reconstructive effort at the time of the primary operation. Cook emphasizes the negative effects of irradiation therapy on the possible success of an implant inserted surgically at a later date. On the other hand, our results demonstrate that it is motivated, already at resection, to attach the mandibular fragments to each other by means of a splint of non-biological inert material. This splint procedure will maintain mandibular continuity, at the same time resulting in a good functional position of the lower jaw in relation to the upper jaw. Elven if, in a certain number of cases, the splint becomes mobile after some months and must be extracted within the first year it still provides sufficient support, during this period, allowing fibrous or osseofibrous union and preventing major deviation of the mandible. This improves the functional situation. The possibilities of a complete reconstruction at a later date after a sufficient period of expectancy thus remain. In quite a few cases, howevcer, the stability obtained by these primary measures is functionally adequate, n o further reconstruction being required. We have used titanium as splint and screw material in all cases because its appropriate metallurgic properties and tissue inertness. Titanium has, in our hands, given the desired mechanical support. During the period evaluated we have made certain modifications of the form and shape of the titanium splint. At first a titanium skeleton was made individually for each patient. Experience from this procedure resulted in the development of thin

123

standardized splints of different lengths which could be adapted to the anatomical situation prevailing during the operation (Fig. 3 b). The elasticity of this splint was intended to promote remodelling of the bone graft by the masticatory load. In some cases, however, fractures or deformities of the splints occurred. This resulted in the development of a J-shaped splint of somewhat larger dimensions (Fig. 3c). When transplanting, we have in the majority of cases used autologous marrow-spongious bone from the iliac crest or the upper tibia1 metaphysis. The results show that this type of graft is not the ideal solution under the special conditions which are prevalent in a mandibular defect with respect to masticatory load and the environment of the transplant. Low density and strength and lack of protection of cortical bone against the environment invalidate the cellularly highly potential graft. In too many cases resorption has occurred to such a degree that the functional and cosmetic results have not been completely satisfactory. Our experience of whole bone grafts is limited, permitting no definite conclusions to be drawn, but the results obtained indicate the superiority of this kind of graft to marrow-spongious bone in the jaw skeleton. Although whole bone transplants composed of a cortical boundary and an interior of marrowspongious bone give better results than bone chips or marrow-spongious bone, they nevertheless sometimes fail, mostly for unknown reasons. Bone transplantation in mandibular defects involves special problems. Firstly, the transplant is positioned close to both mucous membranes and the skin. Secondly, the topographical anatomy and the tissue vitality after resection are often unfavourable for healing. Thirdly, both the need for mechanical stability and the substitution of the remaining defect create special problems. If irradiation is used, the healing capacities are further reduced. The object must be to ensure mandibular continuity during the healing period of such biomechanical properties that adequate stability is achieved, a certain work load at the same time being distributed to the bone graft so that a remodelling stimulus is provided. This means that there is a delicate balance to be struck, because too much movement results not only in loosening of the splint screws but also in resorption of the transplant. This, however, can also be the result of too rigid an immobilization over a prolonged period of time. The Scand J Plast Reconstr Surg 9

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124 P . 4 Brdnemark et al. aim is thus to control and keep within an acceptable range the masticatory forces transmitted to the reconstructed area. We have in some cases tried a new method of autogenous bone grafting to the mandible, involving use of a preformed transplant. The first step in the basic procedure is to shape the graft-to-be by means of titanium moulds and to install titanium screws in it. Screws are also installed in the recipient area at the same time. The preformed transplant becomes vascularized according to the directions of the mould. It is remodelled to its new anatomy, and the screws are incorporated into the bone. The second step then consists in moving the transplant to the mandibular site. The idea is that this procedure should provide a graft which is not so easily invaded by granulation tissue in the mandibular defect area, and also that the graft should in this way retain its intended bone shape and properties. The incorporated screws should also provide better stability at splinting. The preliminary results have so far been promising, but both the number of cases and the follow-up time are at present too limited to allow any definite conclusions. Recent studies have indicated a possibility of preserving the mandibular nerve (Becker, 1970) at resection of the mandible because of non-malignant tumours, such as the cystic form of ameloblastoma. Experimental and clinical work (Hausamen, Samii & Schmidseder, 1973; 1974) shows that a defect of the inferior alveolar nerve can be repaired by autografting of the sural nerve. The methods employed in the treatment of mandibular defects are thus in a state of continuous development becoming more and more refined, the goal being not only to restore skeletal continuity, but also to restore soft-tissue function, like the innervation of mimic musculature, as well as masticatory and phonational functions, by means of a jaw bone anchored bridge (Brinemark et al., 1969; 1970b; 1975). In cases of extensive soft-tissue defects plastic surgical measures can contribute to optimizing the results of rehabilitation. Principles for the Treatment of Defective Mandibles

On the basis of our experimental and clinical experience of reconstruction work concerning defects of the skeleton, especially of the mandible, and of jaw bone implants serving as support for permanent dental bridges, we suggest the following procedures: Scand J Plast Reconstr Surg 9

Instrumental equipment It should normally be possible, for preparation of the tissue as well as for stabilization, to use standardized instrumental equipment. Only in exceptional cases should special constructions be required. This makes heavy demands o n the flexibility of the equipment and presupposes that splints etc., before and during the operation, can be adapted to the defect anatomy at hand. By means of careful preoperative biomechanical analysis at primary reconstruction and per operative measurement at the resection during the first step of a secondary reconstructive procedure, it is often possible to carry out the required adjustments in model work before the surgical reconstruction itself takes place. We use profiled titanium splints made of non-alloyed titanium (AT1 24), having a thickness of 1 mm and a width of 12 mm, with multiple holes for anchoring screws, at a standardized distance from each other. The splints are adjustable as to length and shape, which means that only a few main types are required as basic material. The anchoring screws are of the same dimensions as those of fixtures for bone anchoring of bridges. Therefore, the same equipment of installation instruments can be used, which facilitates surgical work, reduces the preparation trauma and cuts down the cost of treatment.

Handling of tissue The soft tissue is prepared at careful atraumatic dissection, all communication with the oral cavity being scrupulously avoided. If such a communication already exists or has to be established for reasons of resection, the tissue should be closed to the oral cavity in several layers before the mandibular reconstruction is performed. More extensive soft tissue defects may require special plastic surgical measures, both before and after the skeletal reconstruction. Complications arising from the soft tissue after the healingin period, e.g. in the form of fistulas through mucous membrane or skin, are treated with excision and covering of the defect, with a flap technique. Experience has shown that under antibiotic therapy such fistulas will heal over the titanium splint or the transplant, the integrity of the covering soft tissue remaining afterwards. H a r d tissue. At resection as well as at attachment of titanium splints and the treatment of grafts, preparation of bone tissue must be carried out extremely carefully, the aim being not to cause any significant trauma. Thus, low pressure should be applied at drilling, and sharp drills, often exchanged, should be used. Profuse irrigation with physiological saline of room temperature should be employed. Screws for attachment of titanium splints and grafts are installed in predrilled and prethreaded holes, low torque being applied. If possible, the screws should be given such a position that the nerves and vessels in the mandibular canal are not damaged. Reconstructive surgery should be carried out under antibiotic protection.

Postoperative regimen The patient should normally have food in fluid form for 1-2 weeks postoperatively, o r parenteral nutrition for 4-5 days after extensive reconstructions. and after that 6-8 weeks of

Reconstruction of defective mandible 125 fairly large one, whole-bone grafts from 0 s ilium should be used, in accordance with 11. (c) A fracture that has healed in an inadequate functional posirion should be treated with osteotomy, correction of position, and then as indicated above.

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11. Minor defects, with a length of 1-2 (occasionally 3) em, in the corpus area

Fig. 4. Titanium splint securing correct position of fractured

mandible.

puree diet with a gradual transition to normal food. Intermaxillary fixation may be required but, if possible, a certain mobilization should be carried out during the first few postoperative weeks, in order to improve tissue circulation and lymphatic drainage. Choice of the measure to be taken and its duration should be decided on from case to case. During the period of demineralization in the healing, special attention should be paid to the biomechanical situation of the reconstructed region. DifPerent methods of limil.ing its mobility may be employed.

I. Fractures requiring osteosynthetic treatment (a) New fracture. Careful repositioning of the fragments should be carried out in such a way that contact between the bone surfaces is established without interposed soft tissue. A profiled titanium splint is made to assume the appropriate shape. The splint is applied under compression of the fracture fragments to each other, being anchored by means of two or-should stability or fracture anatomy so require-three screws on either side of the fracture (Fig. 4). (6) A pscudarthrosis-healed fracture should be trealed with resection of soft tissues, so that bone and marrow tissue at the fragment ends will constitute the surface of attachment for acute marrow-spongious bone grafts from the proximal tibia1 metaphysis or from the iliac crest. If the defect is a

Continuity is restored with a profiled titanium splint which is anchored by means of 3 screws on either side of the defect. This is filled with a block graft from the iliac bone. The ends are shaped into a wedge and placed in the defect under compression (Fig. 5). The graft should be prepared in such a way that cortical bone is obtained as a demarcation against the oral flap and, preferably, against the chin flap as well. If required, marrowspongious tissue should be packed into the gaps that may occur between the mandibular ends and the black transplant. As a rule, however, it should be possible, through careful adjustment of shape, to connect the marrow-spongious tissues of the graft directly to those of the mandible. Correct mandibular topography is obtained with the aid of a plastic mould, which is placed between the upper jaw and the lower when the titanium splint is attached. With respect to facial symmetry and the function of the mandibular joint special attention should be paid to the position of the angulus area in relation to the median plane.

111. Defects larger than 3 ern in the corpus area, defects involving the angulus and ramus area, and defects where intra-osseous titanium fixtures are required as a base for a dental prosthesis anchored in the mandible In these cases a preformed graft from the iliac bone is used. In this graft are incorporated titanium fixtures for future anchoring of a denture as well as titanium screws for attachment of the graft to the mandibular fragments. A profiled titanium splint is used for achieving continuity between the fragments and for immobilization of the transplant (Fig. 6). The attachment of the graft to the mandibular fragments can be carried out in two ways, depending on the individual

Fig. 5. Titanium splint connecting mandibular fragments and whole bone graft compensating for the skeletal defect. &and J Plast Reronstr Surg 9

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126 P . 4 . Brhemark et al.

Fig. 6. Titanium splint connecting mandibular fragments and preformed whole bone graft in the defect. The graft contains osseo-integrated titanium screws for attachment of the graft to the splint and for jaw bone anchorage of a

bridge. (a) and (b) show the procedure for a defect in the ramus area; (c) the restorative procedure when the defect involves the anterior aspect of the mandible.

Fig. 7. (a) Preparation procedure at preformation of corpus, ramus and caput mandibulae in the iliac bone of the opposite side. (b) Preformed whole bone graft which is connected to the remaining mandibular hone via integrated titanium screws and a titanium splint.

Reconstruction of defective mandible

127

tissue, preformation of the site may also be required, which should then be carried out 2-3 weeks before transplantation. After the transplant has been moved up, a healing period of 4 months is required before a bridge construction can be attached.

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VI. Malignancy and radiation treatment

Fig. 8. Preformed whole bone graft from the tibia with integrated titanium fixtures for reconstruction of the alveolar ridge.

anatomic situation. The titanium splint is either anchored by means of acutely installed titanium screws, o r connected to titanium screws that have already been incorporated. In the latter case the screws are installed into the mandibular fragments at the same seance as the preformation of the graft in the iliac bone is carried out.

IV. Defects involving the temporo-mandibular joint, without preoperative or postoperative radiation treatment The graft intended as a substitute for a removed mandibular part is preformed in the iliac bone, with a special titanium mould for the mandibular head. Titanium screws are also installed into the preformed graft for attachment to a titanium splint when it is moved up to the mandible affer 3-4 months of healing (Fig. 7). Simultaneously with preformation 3 titanium screws for attachment of the titanium splint are installed. Alternatively, the splint can be attached by means of 3 4 titanium screws acutely installed at the transplantation. If the defect comprises a major part of the mandibular body on the side involved and the residual teeth in the remaining original mandible provides an inadequate base for a bridge construction, titanium fixtures may also be installed into the graft, simultaneously with preformation, in order to serve as anchorage for the bridge.

In all of the defect situations described above it has been assumed that no preoperative or postoperative radiation treatment has been given. In certain cases involving radiation treatment, reconstruction by means of a graft may nevertheless be justified. However, the basic principle in a case of a malignant tumour with a risk of relapse and with radiliotion treatment should be the initial restoration of continuity alone. This should be carried out by means of a profiled titanium splint and 3 anchoring screws in either fragment. The soft-part closure inwards to the oral cavity and outwards to the cheek should be performed in different layers and with a meticulous technique. If the joint is involved, a titanium prosthesis for caput mandibulae should be used (Fig. 9). If the defect is a very large one, e.g. as a result of hemimandiblectomy, a titanium joint prosthesis should be used, attached to a profiled titanium splint with an extended connection to the mandibular fragment, which means that 3 4 titanium screws, at a greater distance than usual from each other, should be used for attachment. Intermaxillary fixation may be carried out in certain cases but with a possibility of a certain passive and, occasionally, very careful active mobilization, in consideration of lymphatic drainage and remodelling in the healing hard and soft tissue. If a tumour relapse does not occur and the functional situation so requires, i t may be considered, after an observation time of normally 3-5 years, whether the reconstruction should be continued by means of a preformed whole-bone graft from the iliac bone. This graft may then be connected to the residual mandibular fragment by means of the previously installed titanium splint. I n order to facilitate such a procedure, the primary, stabilizing titanium splint can be attached to the mandible with a mechanical system of such a kind that the splint may temporarily be removed when the graft is to be installed. The titanium screw in the mandible consists of two parts. One of these is incorporated in the mandible, the other part being a locking screw for the splint,

V. Continuous mandibular skeleton with advanced resorption of the alveolar ridge, unfit for use of a conventional denture or a bone anchored bridge Reconstruction of the alveolar ridge is carried out by means

of preformed whole-bone grafts from the proximal ti bial metaphysis, with incorporated titanium fixtures serving as a base for a bridge construction after a healing time of 3-4 months, the graft being attached to the transplantation site by means of titanium screws (Fig. 8). In cases displaying an extreme degree of resorption and fibrotic mucoperiosteal

Fig. 9. Titanium prosthesis for caput mandibulae. Scand J Plast Reronstr Surg 9

128 P.-I. Brcinemark rt al.

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connected to a threaded central hole. A washer is used for locking this screw. Correct functional topography in the mandibular skeleton is obtained by applying the intended titanium splint before resection, adjusting it to the anatomical situation at hand. The anchorage sites for the titanium screws are marked, after which resection is carried out. At secondary reconstruction an intra-oral plastic mould is employed for ensuring the correct position of the lower jaw in relation to the upper when the titanium splint is attached and the fragments topographically corrected.

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Clarke, P. B. 1966. Internal fixation for bone grafts to the mandible. Br J Oral Surg 4 , 95. Conley, J. J. 1953. A technique of immediate bone grafting in the treatment of benign and malignant turnours of the mandible and a review of seventeen consecutive cases. Cancer 6 , 568. Cook, H . P. 1968. Immediate reconstruction of the mandible by metallic implant following resection for neoplasm. Ann R Cull Surg Engl42, 233. Fordyce, G . L. 1970. A new method for the reconstruction of the body of the mandible following resection for recurrent adamantinoma. Br J Oral Surg 8, 237. Hahn, G. W. & Corgill, D. A. 1969. Chrome cobalt mesh mandibular prosthesis. J Oral Surg 27, 5 . Hausamen, J.-E., Samii, M. & Schmidseder, R. 1973. Repair of the mandibular nerve by means of autologous nerve grafting after resection of the lower jaw. J Max-Fac Surg I , 2, 74. - 1974. Restoring sensation to the cut inferior alveolar nerve by direct anastomosis or by free autologous nerve grafting. Plast Reconstr Surg 54, I , 83. Heiss, J . & Grasser, H. 1968. Stabile Osteosynthese mit Platten. Dtsch Zahnaerztl Z 23, 1085. Huebsch, R. F. 1970. The repair of defects of the jaws with cancellous bone chips: Experience with forty cases. Br J Oral Surg 8, 165. Hughes, A. M. & Jordan, B. A. 1974. The mechanical properties of surgical bone screws and some aspects of insertion practice. Injury 4, 25. Ivy, R. & Epes, B. M. 1927. Bone grafting for defects of the mandible. Milit Surg 60, 286. Ivy, R. H . & Eby, J. D. 1958. 39 and 38 year follow-up of mandibular bone grafts in three cases. Plast Reconstr Surg 22, 6 , 548. Leake, D. L. & Rappaport, M. 1972. Mandibular reconstruction: Bone Induction in an alloplastic tray. Surgery 72, 332. Manchester, W. M. 1972. Some technical reconstruction of the mandible and temporomandibular joint. PIast Reconstr Surg 50, 3, 249. Michelet, F. X., Deymes, J. & Dessus, B. 1973. Osteosynthesis with miniaturized screwed plates in maxillo-facial surgery. J Mac-Fac Surg I , 79. Mowlem, R. 1944. Bone grafting. Br J P h r Slug 16, 293. Nahum, A. M. & Boyne, P. J. 1972. Restoration of the mandible following partial resection. Transuctions 76, 4, 957. Redpath, T. H. 1970. Mandibular reconstruction in Nigeria. Br J Oral Surg 9, 85. Robinson, M. 1959. Silver implant in situ fifty-one years after resection of mandible. JAMA 171, 890. Singleton, J. McL. 1970. Malignant ameloblastoma. Br J Orul Surg 8, 154. Snell, J. A. & Dott, W. A. 1969. Internal fixation of certain fractures of the mandible by bone plating. Plast Reconstr Surg 43, 3, 28 1. Southam, J . C. & Selwyn, P. 1970. Structural changes around screws used in the treatment of fractured human mandibles. Br J Oral Surg 8, 2 I I . Uhthoff, H. K. 1973. Mechanical factors influencing the holding power of screws in compact bone. Bone J Surg 55, 3, 633.

Reconstruction of the defective mandible.

In a clinical material consisting of 31 cases of mandibular defects, caused by tumour resection or by trauma, reconstruction has been carried out by m...
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