Clinical Otolaryngology 1977, 2, 373-384
SURGEON’S WORKSHOP Replacement of the central arch of the mandible by an implant H . G . JACOBS A N D G . SELLE Klinik und Poliklinik fur Zahn Mund- und Kiefirkrankkeiten der Georg-August Universitat, Gottingen, West Germany
Accepted f o r publication 10 December 1976
H.G. & SELLE G. (1977) Clinical Otolaryngology 2, 373-384 Replacement of the central arch of the mandible by an implant The use of an alloplastic implant to fill the defect after resection of the central part of the mandible is described. This procedure makes the post-operative course more acceptable for the patient, and facilitates later reconstruction by a free bone graft in the absence of recurrence. JACOBS
Keywords implants head and neck cancer mandible
Introduction
PROBLEMS OF RESECTION OF T H E CENTRE OF T H E MANDIBLE
L.oss of continuity of the mandible after resection of its central arch produces functional and esthetic problems which must be adequately compensated to protect the patient from many postoperative problems. The muscles remaining attached to the mandibular remnants produce different forms of dislocation by their contraction. , 2 At the same time disturbances of occlusion, mastication, speech, swallowing and appearance occur. Respiratory obstruction and aspiration can also occur3 because the origin of the muscles of the floor of the mouth and the tongue is divided during resection of the central part of the mandible. A resection in continuity in the area of the chin leads to esthetic and functional disturbances as a result of shrinkage of the soft tissue4 if immediate reconstruction of the remaining bony support with auto or allo plastic material is not possible. Such difficulties cannot be avoided in some cases if the local circumstances make grafting of the defect impossible; osteo radio necrosis in particular may present an insoluble problem. The guiding principle of treatment of the latter disease should be conservatism5 but many patients require active surgical intervention. This is particuIarly the case if neuralgia occurs, F
373
3 74
H . G . J A C O B S AND G . SELLE
Figure I 80 year old patient wit11 osteoradionecrosis of the mandible; a the clinical appearance; b the radiographs.
Mandibular implants
Figure z The patient shown in Figure graph.
375
I.
a the resected part of the mandible;
b the postoperative radio-
376
H. G . JACOBS AND G . SELLE
if there is no tendency to demarcation, for persistent fistulae and spontaneous fracture. In this case the mandible should be resected with a wide margin to allow intra and extra oral soft tissue cover. Disarticulation alone is no protection against necrosis of the stump and fistula formation of the isolated remaining mandibular ramus. As a result of the radiation the remaining parts of the mandible are less resistant to mechanical stress or minor trauma; there is loss of osteoblasts and development of sclerotic connective tissue in the medullary canal so that an implant is seldom retained. Usually the covering soft tissues are inadequate to provide a satisfactory bed for the implant because of the radiation. This can be illustrated by means of a clinical example: Case I . This was an 80 year old patient who had been irradiated 5 years previously for a carcinoma of the left side of the tongue. A partial glossectomy and radical neck dissection was carried out. Postoperative radiotherapy to a total dose of 12 ooo r was administered in which the horizontal ramus of the mandible on the left side was unprotected in the beam. The patient was referred to us because of pain, sequestrum formation, a fistula, spontaneous fracture and extensive exposure of the mandible which had not responded to treatment (Figure Ia). Radiographs showed the area of bone destruction to extend from the centre of the mandible to the left ascending ramus (Figure Ib). We carried out a radical resection of the part of the mandible affected by osteo-radio necrosis; Figure 2a shows the part of the mandible removed with a spontaneous fracture through the left canine area and the angle of the jaw; Figure 2b shows the postoperative radiographs. Reconstruction of continuity of the mandible could not be contemplated because of the poor condition of the skin, mucosa and bone and because of the advanced age of the patient. As a result of this the patient’s speech and swallowing were severely impaired after the operation. I M M E D I A T E RECONSTRUCTION
The example of this patient demonstrates that reconstruction of the mandible should be striven for at the first operation for resection of the tumour to spare the unfortunate patient such results of the operation. The purpose of the operation is restoration of continuity of the mandible in its correct shape. At the same time normal occlusion of any remaining tooth bearing fragments should be attained.6 The disturbances of function which result from these necessary operative defects should be limited by prophylactic operative and orthodontic procedures. In resection of a benign tumour the bone defect is usually filled by a bone graft,3,7-13but the prerequisites for reconstruction with autologous bone are often absent when dealing with a malignant turnour.’ The size and site of the turnour dictate the site of resection of the soft tissues and of the osteotomy. Bridging of the bone defect is usually only carried out by a bone graft after a sufficiently long period free from recurrence has elapsed. An alloplasty is indicated when a primary osteoplasty is not possible because of an infected
Mandibular implants
377
operative field through the open mouth or because of the danger of recurrence of the t ~ m o u r . ~ Particularly in the region of the chin, an alloplasty provides temporary esthetic and functional reconstruction of the curved chin contour with secure fixation of the mandibular stumps and the correct o ~ c l u s i o n . 'Galindo ~ fixes both fragments after resection of the centre of the chin with stainless steel wire with bayonet-shaped ends, to achieve the above criteria. The wire is introduced into holes already prepared with a drill.6 Fries uses Steinmann pins which are also made of stainless Scheunemann uses silastic reinforced with a Kirschner wire for reconstruction of the chin after resection of the t~mour.~' Spiessl bridges the gap after resection of the centre of the mandible with a horseshoe shaped plate made of titanium with several perforations by which it can be fixed to the peripheral mandibular stumps; if necessary it can also be used to fix a bone graft with which the author aims to achieve the so-called functionally stable graft.' O In resection of the centre of the mandible for tumours we use the method described by Becker & Machtens in which the defect is temporarily filled with a pre-formed titanium implant.
Method We bridge the bony defect of the central arch of the mandible after resection of a malignant tumour with a pre-formed titanium implant which is fixed to the inner compact layer of each stump with two perosseous bony screws with locking nuts. These are the ramus sections of the standard Bowermann-Conroy set.
Results The results are shown in Table
I.
Table Case
I
Results of Bowermann-Conroy implants Date of operation
Sex
Age
I
M
33 May'73
z
M M M F
50 35 75 63
no.
3 4
5
Dec '75 Feb '76 Oct'75 Ju1'73
Site of tumour
Floor of mouth LL LL
Alveolus LL
Fate of Fate of patient graft (Dec '76) (Dec '76) Rejected AIW 8/76 Retained AIW L< AIW LL D. Dec '76
SURGEON’S WORKSHOP Replacement of the central arch of the mandible by an implant H . G . JACOBS A N D G . SELLE Klinik und Poliklinik fur Zahn Mund- und Kiefirkrankkeiten der Georg-August Universitat, Gottingen, West Germany
Accepted f o r publication 10 December 1976
H.G. & SELLE G. (1977) Clinical Otolaryngology 2, 373-384 Replacement of the central arch of the mandible by an implant The use of an alloplastic implant to fill the defect after resection of the central part of the mandible is described. This procedure makes the post-operative course more acceptable for the patient, and facilitates later reconstruction by a free bone graft in the absence of recurrence. JACOBS
Keywords implants head and neck cancer mandible
Introduction
PROBLEMS OF RESECTION OF T H E CENTRE OF T H E MANDIBLE
L.oss of continuity of the mandible after resection of its central arch produces functional and esthetic problems which must be adequately compensated to protect the patient from many postoperative problems. The muscles remaining attached to the mandibular remnants produce different forms of dislocation by their contraction. , 2 At the same time disturbances of occlusion, mastication, speech, swallowing and appearance occur. Respiratory obstruction and aspiration can also occur3 because the origin of the muscles of the floor of the mouth and the tongue is divided during resection of the central part of the mandible. A resection in continuity in the area of the chin leads to esthetic and functional disturbances as a result of shrinkage of the soft tissue4 if immediate reconstruction of the remaining bony support with auto or allo plastic material is not possible. Such difficulties cannot be avoided in some cases if the local circumstances make grafting of the defect impossible; osteo radio necrosis in particular may present an insoluble problem. The guiding principle of treatment of the latter disease should be conservatism5 but many patients require active surgical intervention. This is particuIarly the case if neuralgia occurs, F
373
3 74
H . G . J A C O B S AND G . SELLE
Figure I 80 year old patient wit11 osteoradionecrosis of the mandible; a the clinical appearance; b the radiographs.
Mandibular implants
Figure z The patient shown in Figure graph.
375
I.
a the resected part of the mandible;
b the postoperative radio-
376
H. G . JACOBS AND G . SELLE
if there is no tendency to demarcation, for persistent fistulae and spontaneous fracture. In this case the mandible should be resected with a wide margin to allow intra and extra oral soft tissue cover. Disarticulation alone is no protection against necrosis of the stump and fistula formation of the isolated remaining mandibular ramus. As a result of the radiation the remaining parts of the mandible are less resistant to mechanical stress or minor trauma; there is loss of osteoblasts and development of sclerotic connective tissue in the medullary canal so that an implant is seldom retained. Usually the covering soft tissues are inadequate to provide a satisfactory bed for the implant because of the radiation. This can be illustrated by means of a clinical example: Case I . This was an 80 year old patient who had been irradiated 5 years previously for a carcinoma of the left side of the tongue. A partial glossectomy and radical neck dissection was carried out. Postoperative radiotherapy to a total dose of 12 ooo r was administered in which the horizontal ramus of the mandible on the left side was unprotected in the beam. The patient was referred to us because of pain, sequestrum formation, a fistula, spontaneous fracture and extensive exposure of the mandible which had not responded to treatment (Figure Ia). Radiographs showed the area of bone destruction to extend from the centre of the mandible to the left ascending ramus (Figure Ib). We carried out a radical resection of the part of the mandible affected by osteo-radio necrosis; Figure 2a shows the part of the mandible removed with a spontaneous fracture through the left canine area and the angle of the jaw; Figure 2b shows the postoperative radiographs. Reconstruction of continuity of the mandible could not be contemplated because of the poor condition of the skin, mucosa and bone and because of the advanced age of the patient. As a result of this the patient’s speech and swallowing were severely impaired after the operation. I M M E D I A T E RECONSTRUCTION
The example of this patient demonstrates that reconstruction of the mandible should be striven for at the first operation for resection of the tumour to spare the unfortunate patient such results of the operation. The purpose of the operation is restoration of continuity of the mandible in its correct shape. At the same time normal occlusion of any remaining tooth bearing fragments should be attained.6 The disturbances of function which result from these necessary operative defects should be limited by prophylactic operative and orthodontic procedures. In resection of a benign tumour the bone defect is usually filled by a bone graft,3,7-13but the prerequisites for reconstruction with autologous bone are often absent when dealing with a malignant turnour.’ The size and site of the turnour dictate the site of resection of the soft tissues and of the osteotomy. Bridging of the bone defect is usually only carried out by a bone graft after a sufficiently long period free from recurrence has elapsed. An alloplasty is indicated when a primary osteoplasty is not possible because of an infected
Mandibular implants
377
operative field through the open mouth or because of the danger of recurrence of the t ~ m o u r . ~ Particularly in the region of the chin, an alloplasty provides temporary esthetic and functional reconstruction of the curved chin contour with secure fixation of the mandibular stumps and the correct o ~ c l u s i o n . 'Galindo ~ fixes both fragments after resection of the centre of the chin with stainless steel wire with bayonet-shaped ends, to achieve the above criteria. The wire is introduced into holes already prepared with a drill.6 Fries uses Steinmann pins which are also made of stainless Scheunemann uses silastic reinforced with a Kirschner wire for reconstruction of the chin after resection of the t~mour.~' Spiessl bridges the gap after resection of the centre of the mandible with a horseshoe shaped plate made of titanium with several perforations by which it can be fixed to the peripheral mandibular stumps; if necessary it can also be used to fix a bone graft with which the author aims to achieve the so-called functionally stable graft.' O In resection of the centre of the mandible for tumours we use the method described by Becker & Machtens in which the defect is temporarily filled with a pre-formed titanium implant.
Method We bridge the bony defect of the central arch of the mandible after resection of a malignant tumour with a pre-formed titanium implant which is fixed to the inner compact layer of each stump with two perosseous bony screws with locking nuts. These are the ramus sections of the standard Bowermann-Conroy set.
Results The results are shown in Table
I.
Table Case
I
Results of Bowermann-Conroy implants Date of operation
Sex
Age
I
M
33 May'73
z
M M M F
50 35 75 63
no.
3 4
5
Dec '75 Feb '76 Oct'75 Ju1'73
Site of tumour
Floor of mouth LL LL
Alveolus LL
Fate of Fate of patient graft (Dec '76) (Dec '76) Rejected AIW 8/76 Retained AIW L< AIW LL D. Dec '76
