oral surgery oral medicine oral pathology Withsectionson oral and maxillofacial radiology and endodontics
oral surgery Editor: ROBERT
6. SHIRA,
DDS
School of Dental IMedicine Tufts University 1 Kneeland S,treet Boston, Massmhusetts 02111
Radiologic follow-up of bone transplants to bridge mandibular continuity defects Anna-Lisa Siiderholm, MD, DDS,a Dorrit Hallikainen, Christian Lindqvist, MD, DDS,c Helsinki, Finland HELSINKI
UNIVERSITY
Special1 radiologic
CENTRAL
imaging techniques
MD,b and
HOSPITAL were used to evaluate
the results of nonvascularized
bone grafts
combined with rigid mandibular reconstruction plates. The radiologic findings divided 21 cases into three clearly distinct groups on the basis of resorption: slight (less than 15%), moderate (15% to 30%), and massive (more than 30%) (mean follow-up, 26 months). This division predicted the clinical results well. In contrast to earlier reports, it was shown that rigid plate bridging did not adversely influence the prognosis of the graft. Nor was early plate removal necessary to reach good ossification. Narrow-beam radiography and spiral tornography proved to be excellent tools for adequate evaluation of bone resorption and bony healing of malndibular grafts. (ORAL SURC ORAL MED ORAL PATHOL 1992;73:253-61)
IPermanent reconstruction of the mandible requires bony continuity to allow rehabilitation with dental implants and/or dental prostheses. In the case of a benign disease (benign tumor, traumatic defect), an immediate bonle graft is often indicated. With malignant tumors the timing of the bone transplantation varies. Some surgeons reconstruct the defect with a “Maxillofacial Surgeon, Department of Oral and Maxillofacial Surgery. bSenior Radiologist, Department of Radiology, IV Department of Surgery. CHead,Department of Oral and MaxillofaciaI Surgery. 7/12/36217
vascularized bone graft in conjunction with ablative cancer surgery.’ Others prefer a secondary procedure with the use of a strictly extraoral approach after the primary wound has healed.2, 3 A wait of I to 2 years before the reconstruction to ensure early detection of tumor recurrence has also been advocated.2-8 Numerous techniques for nonvascularized bone grafts have been presented. These include frozen or irradiated autografts from the surgical field, alloplastic or bony trays filled with cancellous bone, and compact grafts from the iliac crest. In cancer surgery, however, high complication rates have been reported, with significant rates of total failures.9-*1 The introduction of different metal prostheses for primary 253
~~A~_%JRGORKL %~EDQRA~~ATHOL March 1992
Fig. IA. .A 39-year-old man (patient 6) with an extensive ameloblastoma of the right mandibular angle. Preoperative panoramic image with large multilocular radiolucency in the right angle.
Fig. 1B. Primary reconstruction performed with an AOTHORP angular plate and bone from the iliac crest. Panoramic image on the first day after surgery. Note the size of the graft.
functional reconstruction has markedly improved the prospects for secondarily performed free-bone grafts. *, 7, l2 Nevertheless, the failure rates have been up to 3076.258 Vascularized free bone grafts are today increasingly used to bridge mandibular defects, especially after large resections in cancer surgery.‘, tje20 However, this technique has limitations with respect to the site and size of the defect, the patient’s general condition, the surgical team available, and the facilities of the institution. Nonvascularized bone grafts are therefore still widely used for mandibular bony reconstruction. The aim of this study was to evaluate the radiologic follow-up and prognosis of nonvascular bone grafts used for permanent mandibular reconstruction. Is it possible to estimate the extent and rate of resorption by radiologic examination? How long a wait is necessary before the determination of whether a graft is a success or a failure?
Fig. IC. Follow-up 2 months after surgery shows moderate resorption. The graft has diminished in height, especially at the distal end, and there is fragmentation of the lower border of the graft.
Follow-up 3 months after surgery. Massive resorption is evident. The graft has nearly disappeared.
Since 1984 rigid plates have been used for primary bridging of mandibular continuity defects at the Department of Oral and Maxillofacial Surgery, Helsmki University Central Hospital. Between 1985 and 1990, 50 reconstructions were performed. To facilitate permanent rehabilitation of the masticatory function with dental implants and/or dental prostheses, 21 sonvascularized free bone grafts were transplanted in 19 patients either at primary surgery (I 1 grafts) or in a second operation (10 grafts). Corticocancellous blocks from the anterior iliac crest were used in all cases. The blocks were usually fixed with either screws or wires. In the body region one block was usually sufficient but several blocks were used in the symphysis and angular region. The plates were removed after bony healing. The mean age of the patients (10 women and 9
Nonvascularized
Volume 73 Number 3 Table
I. Records of patients with radiologically
bone transplant and rigid plates
255
demonstrated good bone healing and excellent resorption
results
A
F M
B c D E
37 40 24 20 50
F
31
M
G H
39 37
Ii4 lb4
M
F IM
Length Of Radiation graft (mm) Timing therapy
Diagnosis
Chondrosarcoma Trauma Trauma Osteoblastoma Trauma C‘EOT Ameloblastoma Trauma
Symphysis Body Angle Body Body Body Angle Body
AO-SRP AO-ARP AO-ARP AO-ARP AO-ARP TH-SRP TH-ARP AO-SRP
P P P P S P
70 20
13 80 10 65 40 60
-
S S
Plate removal Follow-up lmol hoi 12
71
42
59 43
18 10 13 12 -
31 24
18 7 77
Result of transplantation* Excellent Excellent Excellent Excellent Excellent Excellent Exceilent Excellent
Abbreviations: AO-A0 plates (Arbeitsglzmeinschaft fiir Osteosynthesefragen, Stratec). ARP-angular reconstruction plate. CEOT-cementifying epithelial odontogenic tumor, Pindborg’s tumor. P-primary surgery. S-secondary surgery. SRP-straight reconstructllon plate. TH-THORP plates (titanium-coated hollow screw and reconstruction plate system, Stratec). *See Table IV.
Table II. Records of patients with radiologically good resorption results
II
demonstrated slow, continuing bone healing and poor or Length Of
Diagnosis
Patient Age Sex 37
F
Ameloblastoma
67 19
.M
SCC
;M
XC
40
F
SCC
59
M
see
46 23
F F
O’steomyelitis Ameloblastoma
29
F
Ossifying fibroma
Site Body, angle Body Body, ramus Body, angle Body,
ramus Body Body, angle Body
Plate removal Follow-up (4 ho)
(mm)
Timing
Radiation therapy
AO-ARP
65
S
-
14
49
Good
AO-ARP AO-RPC
110 130*
S S
preoperatively preoperatively
12 -
41 39
Good Poor
AO-ARP
80
S
23
21
Good
AO-RPC
95*
S
-
-
18
Poor
TH-SRP TH-ARP
55 85
S P
-
-
11 10
Good Good
TH-SRP
70
S
-
7
Good
Plate used
graft
Result of transplantation f
Abbreviations: AO-A0 plates (Arbeitsgemeinschaft fiir Osteosynthesefragen, Stratec). ARP-angular reconstruction plate. P-primary surgery. RPC--reconstruction plate with condylar head. S-secondary surgery. SCC-squamous cell carcinoma. SRP-straight reconstruction plate. TH-THORP plates (titanium-coated hollow screw and reconstruction plate system, Stratec). *Free-end grafts. Wee Table IV.
men) was 41 years (range, 20 to 79 years). In the majority of cases, the cause of the mandibular defect was segmental rese’ction as a result of a tumor. Seven patients had malignant tumors and six had benign ones
(Tables I, II, and III). The mean follow-up time for all grafts was 26 months. Clinical and radiologic examinations were performed preoperatively and regularly during follow up.
256
Sbderkolm, Hallikainen,
and Lindqvist
ORALSLRG
%LAL
%&oQRAL
PATHOL
March 1992
Fig. 1E. Revision and removal of the graft were performed from an intraoral approach. Two months later a new graft from the iliac crest was installed from a strictly extraoral approach. Detailed narrow-beam image of the
right ramus 3 months after surgery. Note signsof good bony healing.
Cross-sectionai tomography (A) and schematic outline (I?) of the right ramus area 3 months after surgery. (Compare with Fig. 1E.) A thin bony bridge is seen between the graft and the ramus.
Fig. IF. Detailed narrow-beam follow-up. Note bony union. Radiologic
image, after 4 months’
examination
Preoperative radiologic evaluation varied on the basis of the clinical diagnosis and always included panoramic radiography, Towne’s view, and an axial view. Computed tomography and detailed studies (Fig. 1E to Fig. lH, Fig. 2) were performed in most cases. Follow-up examinations included panoramic radiography and detailed imaging with the use of the
ig. H. Cross-sectional tomography (A/ and schematic outline /B) of the right ramus area 6 months after surgery. (Compare with Fig. 1F.j Bony union between graft and raTIllIS.
Nonvascularized
Volume 73 Number 3
Fig.
II.
bone transplant and rigid plates
257
Panoramic image 6 months after surgery.
Fig. 2B. Detailed narrow-beam image 13 months after surgery. The graft has diminished in height and there is a gap between the graft and the mandibular ramus fragment.
Fig. 2A. The mandible was primarily reconstructed with an A0 angular plate after segmental resection of the right body and angle for a squamouscell carcinoma in a 40-yearold woman (patient M). Two years later bone from the iliac crest was transplanted from an extraoral approach. Detailed narrow-beam image on the first day after surgery. Note the height of the graft.
narrow-beam technique and cross-sectional tomography. For these examinations, a Scanora x-ray unit (Orion Corp/Soredex, Helsinki, Finland) was used. Towne’s view was obtained regularly, and theaxial view only occasionally. The grafts were classified by length into two categories: long grafts (length 30 to 130 mm) and short grafts (length 10 to 29 mm). The height of the graft was measured from panoramic and detailed images. The resorption was expressed as a percentage of the height immediately after surgery and scored as follows: slight-O% to 14%; moderate-15% to 30%; and massive-more than 30%.
Bone resorption within the graft and under the plate and bony union between the graft and the mandible were evaluated and recorded. The resorption
Fig. 2C. Detailed narrow-beam image 26 months after surgery. Bony union is seenbetween the graft and the mandibular ramus. The plate has been removed.
within the graft was scored as slight, moderate, or massive. The final results of the reconstructions were classified into four groups as shown in Table IV. RESULTS
The radiologic examinations revealed three different behaviors of the bone grafts: (1) good bony healing, (2) slow, steady resorption, and (3) fast resorption started immediately after surgery.
258
Siiderholm, Hallikainen,
Fig.
2D. Cross-sectional
and Lindqvist
tomography
13-months
ORAL SURG ORAL MED ORAL PATHOL March 1992
after surgery
shows a defect between
the graft
and the
ramus. No signs of bony healing. (Compare with Fig. 2, B.)
Fig. 2E. Cross-sectional tomography 26-months after surgery shows ongoing new bone formation. (Compare with Fig. 2, C.) Slight
or no resorption
In eight cases slight graft resorption (0% to 14%) was recorded within 3 months at the first and second follow-up after surgery, and bone gain (increased graft height) at a later follow-up (mean, 41 months; range, 7 to 7 1 months, Table I) _The first signs of new bone formation were recorded 1 to 3 months after surgery, and bony union between graft and mandible was visible within 11 months in all cases (Fig. 1E to Fig. 1H). Four of these patients had late reconstructions because of traumatic defects. Two of them had primary surgery for a benign tumor and one for a malignant tumor. One patient with a large ameloblastoma of the angular region experienced total failure of a primary bone graft, but the second graft, performed from a strictly extraoral approach, was successful (Fig. 1). None of these patients received radiation therapy. The clinical features are shown in Table I. All patients had excellent function and facial appearance. The plates were removed in all but one patient after a mean interval of 26 months (range, 10 to 77 months; Table I). Moderate
resorption
Moderate resorption (15% to 30%) was recorded for seven patients and continued slowly during the
first year of follow-up (Table II). This resorption was in most cases accompanied by simultaneous bone rebuilding and bony healing. A steady state was usually achieved between 12 and 18 months at a 15% to 30% resorption. In this group, bony healing was delayed at one or both ends of the graft. In three patients, bony union was finally confirmed and the functional and esthetic results were good (Fig. 2). The plates were removed at 12, 14, and 23 months, respectively (Tables II and IV). In two cases dental implants were later installed. Two patients had advanced squamous cell carcinomas that necessitated a hemimandibulectomy, which included a condylar exarticulation. In each case a plate with a condylar head was used for primary reconstruction. One of these plates fractured 22 months after surgery and was replaced by a similar one together with bone from the iliac crest. In the other patient, bone was transplanted to the body area to prevent the same complication. In both cases (patients L and N), the transplanted bone slowly but continuously disappeared, although rebuilding could also be seen radiologically. A bony bridge between graft and mandible was visible at 10 and 15 months, respectively. In terms of masticatory function, the bone transplants did not bring the patients any benefits.
Nonvascularized
Volume 73 Number 3
Table 111.Records
of patients
Patient
Age
Sex
R
61
F
SCC
S
44
F
T
26
F
Gunshot wound Sarcoma
G
39
M
0
46
F
bone transplant and rigid plates
259
with total failure* of transplanted bone graft
Site
Diagnosis
Ameloblastoma
Symphysis body Symphysis, body Symphysis body, ramus Angle
Osteomyelitis
Body
Plate used
Length Of graft (mm)
Timing
Radiation therapy
Remarks
AO-ARP
65
S
-
wrong technique
AO-SRP
120
S
-
wrong technique
W-RPC
220
P
postoperatively
TH-ARP
57
TH-SRP
33
P ‘r P
-
free end graft mucosal wound separation, infection atrophic mandible
Abbreviations: AO-A0 plates (Arbeitsgemeinschaft fiir Osteosynthesefragen, Stratec). ARP-angular reconstruction plate. P-primary surgery. RPC--reconstruction plate with condylar head. S--secondary surgery. SCC-squamous cell carcinoma. SRP-straight reconstiuction plate. TH-THORP plates (titanium-coated hollow screw and reconstruction plate system, Stratec). W-Wiirzburg plates (Leibinger). *See Table IV.
Table IV. Classification Excellent results
Good results
Poor results Total failures
Massive
of results Cases with excellent function and esthetics; no or slight (less than 15%) resorption of the height of the graft; signs of bony healing within 3 months and complete bony union of the transplahts within 11 months of follow-up Cases with good or excellent functional and esthetic goals achieved despite moderate (15% to 30%) resorption; signs of bony healing within 5 months and bony union at one end of the graft within 11 months Cases with bone resorption exceeding 30% within 12 months, with few or no functional benefits Cases with bone grafts either removed because of complications or totally gone at radiologic examination within 6 months
resorption
Massive resorption, exceeding 30% at the first or second postoperative examination, was recorded in five cases (Table III). The resorption was often accompanied by signs of infection. Total failure. was evident within 3 to 4 months (Fig. 1, A-D). The transplanted bone grafts in two patients, performed in 1984 and 1985, failed because the wrong fixation technique was used. At the time of bone transplantation, a long reconstruction plate in the symphysis region was cut in the middle, leaving only short fixation parts at both ends. Infection, fistulation, plate exposure, and removal of both the bone graft and the plate were the end results in both cases. Final clinical
results
Excellent or good final results were achieved for 14 of 21 grafts (67%); 2 of 21 grafts (10%) achieved a
poor result that did not add any functional benefits for the patient; and 5 of 21 grafts (24%) were total failures (Tables I to IV). The surgical field was open to the oral cavity during the procedure in 9 of 21 cases (43%) because of the location of the lesion in question. In 4 of these 9 cases (44%), postoperative infection occurred. The rigid plates were removed an average of 17 months after successful bone transplantation (range 10 to 42 months). In the cases with resorption of less than 15%, the plates had been kept in place longer (mean, 24 months) than in the group showing resorption of 15% to 30% (mean, 17 months). DISCUSSION
The total failure rate of 24% in this series was quite high compared with recent reports that cite figures between 4.1% and 12.8%.2, 6 ’ On the other hand, re-
260
Siiderholm, Hallikainen,
and Lindqvist
sults classified as severe complications, which include pseudoarthrosis, sequestration, and massive resorption, have been reported in 16% to 42% of cases of secondary bone reconstruction using iliac crest.2, * The majority of grafts in this series were large, and the resections had been performed in the treatment of malignant tumors. Two of the total failures were a result of the use of the wrong technique. When nonvascularized bone is used in combination with rigid plate bridging, the plate has to be fixed at both ends in the mandible that remains. Otherwise, the plate will loosen while the transplanted bone is being rebuilt. The need for stability during this technique cannot be neglected without a high risk of complication. Three free end grafts installed in combination with condylar plates showed moderate or massive resorption and a poor final result (two cases) or total failure (one case). There were no functional or esthetic benefits for the patients when compared with the plate alone. Intraoral approach and intraoral contamination of the surgical field have been named as two reasons for high failure rates. 2,*, 21 Others, however, routinely use the oral approach. 4, 6 In four of nine cases in which the lesion in question necessitated an additional intraoral approach, postoperative infection occurred; three resulted in total failure and graft removal. In our opinion, these complications stress the importance of extremely good intraoral wound care and the use of a strict extraoral approach whenever possible. High plate rigidity is said to markedly enhance resorption, and plate removal within 6 months has been recommended.2, 22,23 These findings were not confirmed in the present study. None of the eight patients with good bone healing and resorption of 0% to 14% had their plates removed less than 10 months after installation of the graft. In view of the factors mentioned above, the results in this series, which included a high percentage of large grafts, showed that nonvascularized bone grafts in combination with rigid plate reconstruction still play an important role in permanent mandibular reconstruction in nonradiated patients.24 The technique does not require much time or resources and is particularly valuable in cases of trauma and benign tumors. In malignant-tumor surgery, a defect bridge with rigid reconstruction plates alone is, in our opinion, preferable. It ensures an early good function for the patient. 25,26In view of the high tumor recurrence rates (70% within 2 years) and a 5-year survival rate of 11% to 15% for cancers that involve the mandibular bone,27-29 total restoration of the masticatory function is possible in only a few of these patients.18
ORAL SURG ORAL MED ORAL PATHOL March 1992
Of the one third of patients who survive up to 2 years,25T29 many are additionally treated with radiotherapy, and permanent reconstruction with vascularized bone might be indicated. The radiologic graft appearance, which divided the cases into three clearly distinct groups, predicted the final clinical results well. Slight resorption, not exceeding 15% at 3 to 4 months’ follow up, was a reliable sign of good healing. Four of the five patients with total failure showed massive resorption (more than 30%) within 1 month, and massive resorption was evident in aliof these cases within 3 months. The group of patients with moderate resorption (15% to 30%) was nonhomogeneous in terms of both underlying pathosis and clinical outcome. Despite this, recognition of moderate resorption was of great clinical importance as it influenced patient care and timing of therapy. Grafts with moderate resorption were regarded as a risk group that required frequent follow up in the early postoperative period and a prolonged follow-up time. Radiologic literature on bone graft evaluation is surprisingly sparse.30 Data on evaluation of primary bone tumors3’ and bone allografts32, 33 stress the role of plain film radiographs. This agrees with our experience. The panoramic image works as a “plain film,” as the whole mandibular bone is within the image layer. Tomography was used for specified, selected diagnostic tasks (e. g., to visualize bone resorption within the graft and under the plate). It seems that regular radiologic examination is essential in graft follow up. Special attention must be paid to the imaging technique and image quality. Good spatial resolution and good contrast are necessary, and the imaging procedure must be selected in view of the specified diagnostic task. Close collaboration between clinician and radiologist is beneficial.
REFERENCES 1. Wenig BL, Keller AJ. Rigid internal fixation and vascularized bone grafting in mandibular reconstruction. Clin Plast Surg 1989;16:125-31. 2. Kriiger E, Krumholz K. Results of bone grafting after rigid fixation. J Oral Maxillofac Surg 1984;42:491-6. und 3. Esser E, Montag H. KonventionelleTransplantatchirurgie enossale Implantate: Ein Behandlungskonzept zur Rehabilitation nach radikaler Tumorchirurgie der unteren Mundhahlenetage. Dtsch Z Mund Kiefer Gesichtschir 1987;11:77-87. 4. Stall P, Schilli W. Long-term follow up of donor and recipient sites after autologous bone grafts for reconstruction of the facial skeleton. J Oral Surg 1981;39:676-7. 5. Kruger E. Reconstruction of bone and soft tissue in extensive facial defects. J Oral Maxillofac Surg 1982;40:714-20. 6. Obwegeser HL, Hlussler F, Ibarra E. Behandlung des infizierten Knochentransplantates bei der Unterkieferrekonstruktion. Fortschr Kiefer Gesichtschir 1984;29:76-7. 7. Egyedi P. Wound infection after mandibular reconstruction
Volume 73 Number 3 with autogenous graft. Ann Acad Med Singapore 1986;15: 340-5. 8. Krumholz K. Rekonstruktion des Unterkiefers und Oberkiefers mit Knochen: Ein Bericht iiber 115 Fglle. Dtsch Z Mund Kiefer Gesichtschir 1987;11:408-16. 9. HSltje W-J, Lentrodt J. Infektionen autologer Knochentransplantate nach Defektrekonstruktion desUnterkiefers. Fortschr Kiefer Gesichtschir 1976;20:32-5. 10. Sailer HF. Ergebnissedergleichzeitigen Resektion und Rekonstruktion des Unterkiefers auf oralem Weg. Fortschr Kiefer Gesichtschir 1976;20:45-6. 11. Duncan MJ, Manktelow RT, Zuker RM, Rosen IB. Mandibular reconstruction in the radiated patient: the role of osteocutaneous free tissue transfers. Plast Reconstr Surg 1985; 76:829-40. 12. Spiessl B. A new method of anatomical reconstruction of extensive defects of the mandible with autogenous cancellous bone. J Craniomaxillofac Surg 1980;8:78-83. 13. Taylor GI, ‘TownsendP, Corlett R. Superiority of the deep circumflex iliac vessels as the supply for free groin flaps: experimental work. Plast Reconstr Surg 1979;64:595-604. 14. Baker SR. Reconstruction of mandibular defects with the revascularized free tensor fascia lata osteomyocutaneousflap. Arch Otolaryngol 1981;107:414-8. 15. Rosen IB, Manktelow RT, Zuker RM, Boyd B. Application of microvascular free osteocutaneousflaps in the management of postradiation recmrent oral cancer. Am J Surg 1985; 150:474-9. 16. Soutar DS, McGregor IA. The radial forearm in intraoral reconstruction: the experience of 60 consecutivecases.Plast Reconstr Surg 198&7&l-8. 17. Zuker RM, Manktlelow RT. The dorsalis pedis free flap: technique of elevation, foot closure, and flap application. Plast Reconstr Surg 1986;77:93-102. 18. David DJ, Tan E, Katsaros J, Sheen R. Mandibular reconstruction with vascularized iliac crest: a IO-year experience. Plast Reconstr Sur,g 1988;82:792-801. 19. Lyberg T, Olstad GA. The vascularized tibular flap for mandibular reconstruction. J Craniomaxillofac Surg 1991; 19:113X 20. Fig LM, Shulkin BL, Sullivan MJ, Rubinstein MI, Baker SR. Utility of emission tomography in evaluation of mandibular bone grafts. Arch Otolaryngol Head Neck Surg 1990; 116:191-6.
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261
21. Lawson W, Biller HF. Mandibular reconstruction: bone graft techniques. Otolaryngol Head Neck Surg 1982;90:589-94. 22. Lentrodt J, Fritzemeier CLJ, Bethmann I. Beitrag zur osteoplastischen Rekonstruktion des Unterkiefers. Dtsch Z Mund Kiefer Gesichtchir 1985;9:5-19. 23. Kennedy MC, Tucker MR, Lester GE, Buckley MJ. Histomorphometric evaluation of stress shielding in mandibular continuity defects treated with rigid fixation plates and bone grafts. Int J Oral Maxillofac Surg 1989;18:170-4. 24. Piggot TA, Logan AM. Mandibular reconstruction by “simple” bone graft. Br J Plast Surg 1983;36:9-15. 25. Gullane PJ, Havas TE. Mandibular reconstruction after cancer surgery. Facial Plast Surg 1987;4:221-31. 26. Saunders JR, Hirata RM, Jaques DA. Definitive mandibular replacement using reconstruction plates. Am J Surg 1990; 160:387-9. 27. Waterhouse JAH. Cancer handbook of epidemiology and prognosis. Edinburgh: Churchill Livingstone, 1974:20-l. 28. Snow JB, Gelber RD, Kramer S, Davis LW, Marcia1 VA, Lowry LD. Randomized preoperative and postoperative radiation therapy for patients with carcinoma of the head and neck: preliminary report. Laryngoscope 1980;96:930-45. 29. Siiderholm A-L, Lindqvist C, Sankila R, Pukkala E$Teppo L. Evaluation of various treatments for carcinoma of the mandibular region. Br J Oral Maxillofac Surg 1991;29:223-9. 30. Bowerman JW, Huges LJ. Radiology of bone grafts. Radio1 Clin North Am 1975;13:67-77. 31. Moser RP, Madewell JE. An approach to primary bone tumours. Radio1 Clin North Am 1987;25:1049-93. 32. Kattapuram SV, Phillips WC, Mankin HJ. Giant cell tumor of bone: radiographic changes following local excision and allograft replacement. Radiology 1986;161:493-8. 33. Kattapuram SV, Phillips WC, Mankin HJ. Intercalary bone allografts: radiographic evaluation. Radiology 1989;170:13741. Reprint requests:
Anna-Lisa Sbderholm, MD, DDS Department of Oral and Maxillofacial Surgery Helsinki University Central Hospital Kasarmikatu 11 SF-00130 Helsinki, Finland
oral surgery Editor: ROBERT
6. SHIRA,
DDS
School of Dental IMedicine Tufts University 1 Kneeland S,treet Boston, Massmhusetts 02111
Radiologic follow-up of bone transplants to bridge mandibular continuity defects Anna-Lisa Siiderholm, MD, DDS,a Dorrit Hallikainen, Christian Lindqvist, MD, DDS,c Helsinki, Finland HELSINKI
UNIVERSITY
Special1 radiologic
CENTRAL
imaging techniques
MD,b and
HOSPITAL were used to evaluate
the results of nonvascularized
bone grafts
combined with rigid mandibular reconstruction plates. The radiologic findings divided 21 cases into three clearly distinct groups on the basis of resorption: slight (less than 15%), moderate (15% to 30%), and massive (more than 30%) (mean follow-up, 26 months). This division predicted the clinical results well. In contrast to earlier reports, it was shown that rigid plate bridging did not adversely influence the prognosis of the graft. Nor was early plate removal necessary to reach good ossification. Narrow-beam radiography and spiral tornography proved to be excellent tools for adequate evaluation of bone resorption and bony healing of malndibular grafts. (ORAL SURC ORAL MED ORAL PATHOL 1992;73:253-61)
IPermanent reconstruction of the mandible requires bony continuity to allow rehabilitation with dental implants and/or dental prostheses. In the case of a benign disease (benign tumor, traumatic defect), an immediate bonle graft is often indicated. With malignant tumors the timing of the bone transplantation varies. Some surgeons reconstruct the defect with a “Maxillofacial Surgeon, Department of Oral and Maxillofacial Surgery. bSenior Radiologist, Department of Radiology, IV Department of Surgery. CHead,Department of Oral and MaxillofaciaI Surgery. 7/12/36217
vascularized bone graft in conjunction with ablative cancer surgery.’ Others prefer a secondary procedure with the use of a strictly extraoral approach after the primary wound has healed.2, 3 A wait of I to 2 years before the reconstruction to ensure early detection of tumor recurrence has also been advocated.2-8 Numerous techniques for nonvascularized bone grafts have been presented. These include frozen or irradiated autografts from the surgical field, alloplastic or bony trays filled with cancellous bone, and compact grafts from the iliac crest. In cancer surgery, however, high complication rates have been reported, with significant rates of total failures.9-*1 The introduction of different metal prostheses for primary 253
~~A~_%JRGORKL %~EDQRA~~ATHOL March 1992
Fig. IA. .A 39-year-old man (patient 6) with an extensive ameloblastoma of the right mandibular angle. Preoperative panoramic image with large multilocular radiolucency in the right angle.
Fig. 1B. Primary reconstruction performed with an AOTHORP angular plate and bone from the iliac crest. Panoramic image on the first day after surgery. Note the size of the graft.
functional reconstruction has markedly improved the prospects for secondarily performed free-bone grafts. *, 7, l2 Nevertheless, the failure rates have been up to 3076.258 Vascularized free bone grafts are today increasingly used to bridge mandibular defects, especially after large resections in cancer surgery.‘, tje20 However, this technique has limitations with respect to the site and size of the defect, the patient’s general condition, the surgical team available, and the facilities of the institution. Nonvascularized bone grafts are therefore still widely used for mandibular bony reconstruction. The aim of this study was to evaluate the radiologic follow-up and prognosis of nonvascular bone grafts used for permanent mandibular reconstruction. Is it possible to estimate the extent and rate of resorption by radiologic examination? How long a wait is necessary before the determination of whether a graft is a success or a failure?
Fig. IC. Follow-up 2 months after surgery shows moderate resorption. The graft has diminished in height, especially at the distal end, and there is fragmentation of the lower border of the graft.
Follow-up 3 months after surgery. Massive resorption is evident. The graft has nearly disappeared.
Since 1984 rigid plates have been used for primary bridging of mandibular continuity defects at the Department of Oral and Maxillofacial Surgery, Helsmki University Central Hospital. Between 1985 and 1990, 50 reconstructions were performed. To facilitate permanent rehabilitation of the masticatory function with dental implants and/or dental prostheses, 21 sonvascularized free bone grafts were transplanted in 19 patients either at primary surgery (I 1 grafts) or in a second operation (10 grafts). Corticocancellous blocks from the anterior iliac crest were used in all cases. The blocks were usually fixed with either screws or wires. In the body region one block was usually sufficient but several blocks were used in the symphysis and angular region. The plates were removed after bony healing. The mean age of the patients (10 women and 9
Nonvascularized
Volume 73 Number 3 Table
I. Records of patients with radiologically
bone transplant and rigid plates
255
demonstrated good bone healing and excellent resorption
results
A
F M
B c D E
37 40 24 20 50
F
31
M
G H
39 37
Ii4 lb4
M
F IM
Length Of Radiation graft (mm) Timing therapy
Diagnosis
Chondrosarcoma Trauma Trauma Osteoblastoma Trauma C‘EOT Ameloblastoma Trauma
Symphysis Body Angle Body Body Body Angle Body
AO-SRP AO-ARP AO-ARP AO-ARP AO-ARP TH-SRP TH-ARP AO-SRP
P P P P S P
70 20
13 80 10 65 40 60
-
S S
Plate removal Follow-up lmol hoi 12
71
42
59 43
18 10 13 12 -
31 24
18 7 77
Result of transplantation* Excellent Excellent Excellent Excellent Excellent Excellent Exceilent Excellent
Abbreviations: AO-A0 plates (Arbeitsglzmeinschaft fiir Osteosynthesefragen, Stratec). ARP-angular reconstruction plate. CEOT-cementifying epithelial odontogenic tumor, Pindborg’s tumor. P-primary surgery. S-secondary surgery. SRP-straight reconstructllon plate. TH-THORP plates (titanium-coated hollow screw and reconstruction plate system, Stratec). *See Table IV.
Table II. Records of patients with radiologically good resorption results
II
demonstrated slow, continuing bone healing and poor or Length Of
Diagnosis
Patient Age Sex 37
F
Ameloblastoma
67 19
.M
SCC
;M
XC
40
F
SCC
59
M
see
46 23
F F
O’steomyelitis Ameloblastoma
29
F
Ossifying fibroma
Site Body, angle Body Body, ramus Body, angle Body,
ramus Body Body, angle Body
Plate removal Follow-up (4 ho)
(mm)
Timing
Radiation therapy
AO-ARP
65
S
-
14
49
Good
AO-ARP AO-RPC
110 130*
S S
preoperatively preoperatively
12 -
41 39
Good Poor
AO-ARP
80
S
23
21
Good
AO-RPC
95*
S
-
-
18
Poor
TH-SRP TH-ARP
55 85
S P
-
-
11 10
Good Good
TH-SRP
70
S
-
7
Good
Plate used
graft
Result of transplantation f
Abbreviations: AO-A0 plates (Arbeitsgemeinschaft fiir Osteosynthesefragen, Stratec). ARP-angular reconstruction plate. P-primary surgery. RPC--reconstruction plate with condylar head. S-secondary surgery. SCC-squamous cell carcinoma. SRP-straight reconstruction plate. TH-THORP plates (titanium-coated hollow screw and reconstruction plate system, Stratec). *Free-end grafts. Wee Table IV.
men) was 41 years (range, 20 to 79 years). In the majority of cases, the cause of the mandibular defect was segmental rese’ction as a result of a tumor. Seven patients had malignant tumors and six had benign ones
(Tables I, II, and III). The mean follow-up time for all grafts was 26 months. Clinical and radiologic examinations were performed preoperatively and regularly during follow up.
256
Sbderkolm, Hallikainen,
and Lindqvist
ORALSLRG
%LAL
%&oQRAL
PATHOL
March 1992
Fig. 1E. Revision and removal of the graft were performed from an intraoral approach. Two months later a new graft from the iliac crest was installed from a strictly extraoral approach. Detailed narrow-beam image of the
right ramus 3 months after surgery. Note signsof good bony healing.
Cross-sectionai tomography (A) and schematic outline (I?) of the right ramus area 3 months after surgery. (Compare with Fig. 1E.) A thin bony bridge is seen between the graft and the ramus.
Fig. IF. Detailed narrow-beam follow-up. Note bony union. Radiologic
image, after 4 months’
examination
Preoperative radiologic evaluation varied on the basis of the clinical diagnosis and always included panoramic radiography, Towne’s view, and an axial view. Computed tomography and detailed studies (Fig. 1E to Fig. lH, Fig. 2) were performed in most cases. Follow-up examinations included panoramic radiography and detailed imaging with the use of the
ig. H. Cross-sectional tomography (A/ and schematic outline /B) of the right ramus area 6 months after surgery. (Compare with Fig. 1F.j Bony union between graft and raTIllIS.
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Fig.
II.
bone transplant and rigid plates
257
Panoramic image 6 months after surgery.
Fig. 2B. Detailed narrow-beam image 13 months after surgery. The graft has diminished in height and there is a gap between the graft and the mandibular ramus fragment.
Fig. 2A. The mandible was primarily reconstructed with an A0 angular plate after segmental resection of the right body and angle for a squamouscell carcinoma in a 40-yearold woman (patient M). Two years later bone from the iliac crest was transplanted from an extraoral approach. Detailed narrow-beam image on the first day after surgery. Note the height of the graft.
narrow-beam technique and cross-sectional tomography. For these examinations, a Scanora x-ray unit (Orion Corp/Soredex, Helsinki, Finland) was used. Towne’s view was obtained regularly, and theaxial view only occasionally. The grafts were classified by length into two categories: long grafts (length 30 to 130 mm) and short grafts (length 10 to 29 mm). The height of the graft was measured from panoramic and detailed images. The resorption was expressed as a percentage of the height immediately after surgery and scored as follows: slight-O% to 14%; moderate-15% to 30%; and massive-more than 30%.
Bone resorption within the graft and under the plate and bony union between the graft and the mandible were evaluated and recorded. The resorption
Fig. 2C. Detailed narrow-beam image 26 months after surgery. Bony union is seenbetween the graft and the mandibular ramus. The plate has been removed.
within the graft was scored as slight, moderate, or massive. The final results of the reconstructions were classified into four groups as shown in Table IV. RESULTS
The radiologic examinations revealed three different behaviors of the bone grafts: (1) good bony healing, (2) slow, steady resorption, and (3) fast resorption started immediately after surgery.
258
Siiderholm, Hallikainen,
Fig.
2D. Cross-sectional
and Lindqvist
tomography
13-months
ORAL SURG ORAL MED ORAL PATHOL March 1992
after surgery
shows a defect between
the graft
and the
ramus. No signs of bony healing. (Compare with Fig. 2, B.)
Fig. 2E. Cross-sectional tomography 26-months after surgery shows ongoing new bone formation. (Compare with Fig. 2, C.) Slight
or no resorption
In eight cases slight graft resorption (0% to 14%) was recorded within 3 months at the first and second follow-up after surgery, and bone gain (increased graft height) at a later follow-up (mean, 41 months; range, 7 to 7 1 months, Table I) _The first signs of new bone formation were recorded 1 to 3 months after surgery, and bony union between graft and mandible was visible within 11 months in all cases (Fig. 1E to Fig. 1H). Four of these patients had late reconstructions because of traumatic defects. Two of them had primary surgery for a benign tumor and one for a malignant tumor. One patient with a large ameloblastoma of the angular region experienced total failure of a primary bone graft, but the second graft, performed from a strictly extraoral approach, was successful (Fig. 1). None of these patients received radiation therapy. The clinical features are shown in Table I. All patients had excellent function and facial appearance. The plates were removed in all but one patient after a mean interval of 26 months (range, 10 to 77 months; Table I). Moderate
resorption
Moderate resorption (15% to 30%) was recorded for seven patients and continued slowly during the
first year of follow-up (Table II). This resorption was in most cases accompanied by simultaneous bone rebuilding and bony healing. A steady state was usually achieved between 12 and 18 months at a 15% to 30% resorption. In this group, bony healing was delayed at one or both ends of the graft. In three patients, bony union was finally confirmed and the functional and esthetic results were good (Fig. 2). The plates were removed at 12, 14, and 23 months, respectively (Tables II and IV). In two cases dental implants were later installed. Two patients had advanced squamous cell carcinomas that necessitated a hemimandibulectomy, which included a condylar exarticulation. In each case a plate with a condylar head was used for primary reconstruction. One of these plates fractured 22 months after surgery and was replaced by a similar one together with bone from the iliac crest. In the other patient, bone was transplanted to the body area to prevent the same complication. In both cases (patients L and N), the transplanted bone slowly but continuously disappeared, although rebuilding could also be seen radiologically. A bony bridge between graft and mandible was visible at 10 and 15 months, respectively. In terms of masticatory function, the bone transplants did not bring the patients any benefits.
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Volume 73 Number 3
Table 111.Records
of patients
Patient
Age
Sex
R
61
F
SCC
S
44
F
T
26
F
Gunshot wound Sarcoma
G
39
M
0
46
F
bone transplant and rigid plates
259
with total failure* of transplanted bone graft
Site
Diagnosis
Ameloblastoma
Symphysis body Symphysis, body Symphysis body, ramus Angle
Osteomyelitis
Body
Plate used
Length Of graft (mm)
Timing
Radiation therapy
Remarks
AO-ARP
65
S
-
wrong technique
AO-SRP
120
S
-
wrong technique
W-RPC
220
P
postoperatively
TH-ARP
57
TH-SRP
33
P ‘r P
-
free end graft mucosal wound separation, infection atrophic mandible
Abbreviations: AO-A0 plates (Arbeitsgemeinschaft fiir Osteosynthesefragen, Stratec). ARP-angular reconstruction plate. P-primary surgery. RPC--reconstruction plate with condylar head. S--secondary surgery. SCC-squamous cell carcinoma. SRP-straight reconstiuction plate. TH-THORP plates (titanium-coated hollow screw and reconstruction plate system, Stratec). W-Wiirzburg plates (Leibinger). *See Table IV.
Table IV. Classification Excellent results
Good results
Poor results Total failures
Massive
of results Cases with excellent function and esthetics; no or slight (less than 15%) resorption of the height of the graft; signs of bony healing within 3 months and complete bony union of the transplahts within 11 months of follow-up Cases with good or excellent functional and esthetic goals achieved despite moderate (15% to 30%) resorption; signs of bony healing within 5 months and bony union at one end of the graft within 11 months Cases with bone resorption exceeding 30% within 12 months, with few or no functional benefits Cases with bone grafts either removed because of complications or totally gone at radiologic examination within 6 months
resorption
Massive resorption, exceeding 30% at the first or second postoperative examination, was recorded in five cases (Table III). The resorption was often accompanied by signs of infection. Total failure. was evident within 3 to 4 months (Fig. 1, A-D). The transplanted bone grafts in two patients, performed in 1984 and 1985, failed because the wrong fixation technique was used. At the time of bone transplantation, a long reconstruction plate in the symphysis region was cut in the middle, leaving only short fixation parts at both ends. Infection, fistulation, plate exposure, and removal of both the bone graft and the plate were the end results in both cases. Final clinical
results
Excellent or good final results were achieved for 14 of 21 grafts (67%); 2 of 21 grafts (10%) achieved a
poor result that did not add any functional benefits for the patient; and 5 of 21 grafts (24%) were total failures (Tables I to IV). The surgical field was open to the oral cavity during the procedure in 9 of 21 cases (43%) because of the location of the lesion in question. In 4 of these 9 cases (44%), postoperative infection occurred. The rigid plates were removed an average of 17 months after successful bone transplantation (range 10 to 42 months). In the cases with resorption of less than 15%, the plates had been kept in place longer (mean, 24 months) than in the group showing resorption of 15% to 30% (mean, 17 months). DISCUSSION
The total failure rate of 24% in this series was quite high compared with recent reports that cite figures between 4.1% and 12.8%.2, 6 ’ On the other hand, re-
260
Siiderholm, Hallikainen,
and Lindqvist
sults classified as severe complications, which include pseudoarthrosis, sequestration, and massive resorption, have been reported in 16% to 42% of cases of secondary bone reconstruction using iliac crest.2, * The majority of grafts in this series were large, and the resections had been performed in the treatment of malignant tumors. Two of the total failures were a result of the use of the wrong technique. When nonvascularized bone is used in combination with rigid plate bridging, the plate has to be fixed at both ends in the mandible that remains. Otherwise, the plate will loosen while the transplanted bone is being rebuilt. The need for stability during this technique cannot be neglected without a high risk of complication. Three free end grafts installed in combination with condylar plates showed moderate or massive resorption and a poor final result (two cases) or total failure (one case). There were no functional or esthetic benefits for the patients when compared with the plate alone. Intraoral approach and intraoral contamination of the surgical field have been named as two reasons for high failure rates. 2,*, 21 Others, however, routinely use the oral approach. 4, 6 In four of nine cases in which the lesion in question necessitated an additional intraoral approach, postoperative infection occurred; three resulted in total failure and graft removal. In our opinion, these complications stress the importance of extremely good intraoral wound care and the use of a strict extraoral approach whenever possible. High plate rigidity is said to markedly enhance resorption, and plate removal within 6 months has been recommended.2, 22,23 These findings were not confirmed in the present study. None of the eight patients with good bone healing and resorption of 0% to 14% had their plates removed less than 10 months after installation of the graft. In view of the factors mentioned above, the results in this series, which included a high percentage of large grafts, showed that nonvascularized bone grafts in combination with rigid plate reconstruction still play an important role in permanent mandibular reconstruction in nonradiated patients.24 The technique does not require much time or resources and is particularly valuable in cases of trauma and benign tumors. In malignant-tumor surgery, a defect bridge with rigid reconstruction plates alone is, in our opinion, preferable. It ensures an early good function for the patient. 25,26In view of the high tumor recurrence rates (70% within 2 years) and a 5-year survival rate of 11% to 15% for cancers that involve the mandibular bone,27-29 total restoration of the masticatory function is possible in only a few of these patients.18
ORAL SURG ORAL MED ORAL PATHOL March 1992
Of the one third of patients who survive up to 2 years,25T29 many are additionally treated with radiotherapy, and permanent reconstruction with vascularized bone might be indicated. The radiologic graft appearance, which divided the cases into three clearly distinct groups, predicted the final clinical results well. Slight resorption, not exceeding 15% at 3 to 4 months’ follow up, was a reliable sign of good healing. Four of the five patients with total failure showed massive resorption (more than 30%) within 1 month, and massive resorption was evident in aliof these cases within 3 months. The group of patients with moderate resorption (15% to 30%) was nonhomogeneous in terms of both underlying pathosis and clinical outcome. Despite this, recognition of moderate resorption was of great clinical importance as it influenced patient care and timing of therapy. Grafts with moderate resorption were regarded as a risk group that required frequent follow up in the early postoperative period and a prolonged follow-up time. Radiologic literature on bone graft evaluation is surprisingly sparse.30 Data on evaluation of primary bone tumors3’ and bone allografts32, 33 stress the role of plain film radiographs. This agrees with our experience. The panoramic image works as a “plain film,” as the whole mandibular bone is within the image layer. Tomography was used for specified, selected diagnostic tasks (e. g., to visualize bone resorption within the graft and under the plate). It seems that regular radiologic examination is essential in graft follow up. Special attention must be paid to the imaging technique and image quality. Good spatial resolution and good contrast are necessary, and the imaging procedure must be selected in view of the specified diagnostic task. Close collaboration between clinician and radiologist is beneficial.
REFERENCES 1. Wenig BL, Keller AJ. Rigid internal fixation and vascularized bone grafting in mandibular reconstruction. Clin Plast Surg 1989;16:125-31. 2. Kriiger E, Krumholz K. Results of bone grafting after rigid fixation. J Oral Maxillofac Surg 1984;42:491-6. und 3. Esser E, Montag H. KonventionelleTransplantatchirurgie enossale Implantate: Ein Behandlungskonzept zur Rehabilitation nach radikaler Tumorchirurgie der unteren Mundhahlenetage. Dtsch Z Mund Kiefer Gesichtschir 1987;11:77-87. 4. Stall P, Schilli W. Long-term follow up of donor and recipient sites after autologous bone grafts for reconstruction of the facial skeleton. J Oral Surg 1981;39:676-7. 5. Kruger E. Reconstruction of bone and soft tissue in extensive facial defects. J Oral Maxillofac Surg 1982;40:714-20. 6. Obwegeser HL, Hlussler F, Ibarra E. Behandlung des infizierten Knochentransplantates bei der Unterkieferrekonstruktion. Fortschr Kiefer Gesichtschir 1984;29:76-7. 7. Egyedi P. Wound infection after mandibular reconstruction
Volume 73 Number 3 with autogenous graft. Ann Acad Med Singapore 1986;15: 340-5. 8. Krumholz K. Rekonstruktion des Unterkiefers und Oberkiefers mit Knochen: Ein Bericht iiber 115 Fglle. Dtsch Z Mund Kiefer Gesichtschir 1987;11:408-16. 9. HSltje W-J, Lentrodt J. Infektionen autologer Knochentransplantate nach Defektrekonstruktion desUnterkiefers. Fortschr Kiefer Gesichtschir 1976;20:32-5. 10. Sailer HF. Ergebnissedergleichzeitigen Resektion und Rekonstruktion des Unterkiefers auf oralem Weg. Fortschr Kiefer Gesichtschir 1976;20:45-6. 11. Duncan MJ, Manktelow RT, Zuker RM, Rosen IB. Mandibular reconstruction in the radiated patient: the role of osteocutaneous free tissue transfers. Plast Reconstr Surg 1985; 76:829-40. 12. Spiessl B. A new method of anatomical reconstruction of extensive defects of the mandible with autogenous cancellous bone. J Craniomaxillofac Surg 1980;8:78-83. 13. Taylor GI, ‘TownsendP, Corlett R. Superiority of the deep circumflex iliac vessels as the supply for free groin flaps: experimental work. Plast Reconstr Surg 1979;64:595-604. 14. Baker SR. Reconstruction of mandibular defects with the revascularized free tensor fascia lata osteomyocutaneousflap. Arch Otolaryngol 1981;107:414-8. 15. Rosen IB, Manktelow RT, Zuker RM, Boyd B. Application of microvascular free osteocutaneousflaps in the management of postradiation recmrent oral cancer. Am J Surg 1985; 150:474-9. 16. Soutar DS, McGregor IA. The radial forearm in intraoral reconstruction: the experience of 60 consecutivecases.Plast Reconstr Surg 198&7&l-8. 17. Zuker RM, Manktlelow RT. The dorsalis pedis free flap: technique of elevation, foot closure, and flap application. Plast Reconstr Surg 1986;77:93-102. 18. David DJ, Tan E, Katsaros J, Sheen R. Mandibular reconstruction with vascularized iliac crest: a IO-year experience. Plast Reconstr Sur,g 1988;82:792-801. 19. Lyberg T, Olstad GA. The vascularized tibular flap for mandibular reconstruction. J Craniomaxillofac Surg 1991; 19:113X 20. Fig LM, Shulkin BL, Sullivan MJ, Rubinstein MI, Baker SR. Utility of emission tomography in evaluation of mandibular bone grafts. Arch Otolaryngol Head Neck Surg 1990; 116:191-6.
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21. Lawson W, Biller HF. Mandibular reconstruction: bone graft techniques. Otolaryngol Head Neck Surg 1982;90:589-94. 22. Lentrodt J, Fritzemeier CLJ, Bethmann I. Beitrag zur osteoplastischen Rekonstruktion des Unterkiefers. Dtsch Z Mund Kiefer Gesichtchir 1985;9:5-19. 23. Kennedy MC, Tucker MR, Lester GE, Buckley MJ. Histomorphometric evaluation of stress shielding in mandibular continuity defects treated with rigid fixation plates and bone grafts. Int J Oral Maxillofac Surg 1989;18:170-4. 24. Piggot TA, Logan AM. Mandibular reconstruction by “simple” bone graft. Br J Plast Surg 1983;36:9-15. 25. Gullane PJ, Havas TE. Mandibular reconstruction after cancer surgery. Facial Plast Surg 1987;4:221-31. 26. Saunders JR, Hirata RM, Jaques DA. Definitive mandibular replacement using reconstruction plates. Am J Surg 1990; 160:387-9. 27. Waterhouse JAH. Cancer handbook of epidemiology and prognosis. Edinburgh: Churchill Livingstone, 1974:20-l. 28. Snow JB, Gelber RD, Kramer S, Davis LW, Marcia1 VA, Lowry LD. Randomized preoperative and postoperative radiation therapy for patients with carcinoma of the head and neck: preliminary report. Laryngoscope 1980;96:930-45. 29. Siiderholm A-L, Lindqvist C, Sankila R, Pukkala E$Teppo L. Evaluation of various treatments for carcinoma of the mandibular region. Br J Oral Maxillofac Surg 1991;29:223-9. 30. Bowerman JW, Huges LJ. Radiology of bone grafts. Radio1 Clin North Am 1975;13:67-77. 31. Moser RP, Madewell JE. An approach to primary bone tumours. Radio1 Clin North Am 1987;25:1049-93. 32. Kattapuram SV, Phillips WC, Mankin HJ. Giant cell tumor of bone: radiographic changes following local excision and allograft replacement. Radiology 1986;161:493-8. 33. Kattapuram SV, Phillips WC, Mankin HJ. Intercalary bone allografts: radiographic evaluation. Radiology 1989;170:13741. Reprint requests:
Anna-Lisa Sbderholm, MD, DDS Department of Oral and Maxillofacial Surgery Helsinki University Central Hospital Kasarmikatu 11 SF-00130 Helsinki, Finland
