CLINICAL
RTICL
J Oral Maxillofac Su,g 48 :554-558. 1990
Reconstruction of Alveolar Clefts With Mandibular or Iliac Crest Bone Grafts: A Comparative Study STEEN SINDET-PEDERSEN, DDS,· AND HANS ENEMARK, DDSt The aim of this study was to compare the results of treatment obtained with mandibular symphyseal and iliac crest bone grafts used for reconstruction of alveolar clefts. The study included 40 patients with unilateral cleft lip palate (UCLP): 20 consecutive patients whose defects were reconstructed with mandibular bone grafts (MBG) and 20 randomly selected UCLP patients who underwent reconstruction with iliac crest bone (ICB). The age at surgery varied from 8 to 13 years (mean age MBG group, 9.1 years; ICB group, 10.3 years), and the postoperative observation period varied from 12 to 33 months (mean, 19 months). Transverse expansion of the maxilla was not completed until after the bone grafting in the group of patients receiving MBGs, whereas it was completed before surgery in the ICB group. The observed marginal bone level on cleft-related teeth was similar in both groups. No periodontal complications were present in any of the patients, and the amount of attached gingiva was similar in both groups. In the MBG group, 15% of the canines were retained, whereas 20% of the canines were retained in the ICB group. The only complication that developed was in a patient from the MBG group, in whom a partial dehiscence of the donor site was observed. The results of this study demonstrate that reconstruction of alveolar clefts with MBG or ICB has a comparable prognosis. The use of MBGs in these patients has several advantages compared with ICB, including reduced operating time, reduced morbidity, reduced hospitalization time, and finally, a cutaneous scar at the iliac crest can be avoided.
Reconstruction of alveolar process defects in cleft patients with bone grafts is a well documented and commonly used procedure. The iliac crest has been the preferred donor site in most centers,' but recently the use of intramembranous bone grafts has gained increasing attention in the literature.F" Iliac crest bone (ICB) grafts have been used in our
center for alveolar cleft reconstruction since 1972 with satisfactory results.I-" However, due to the easier access to the donor site using mandibular bone grafts (MBGs) and the tendency of intramembranous bone grafts to maintain more of their volume than enchondral bone grafts ,9 -1 1 we started using MBGs for reconstruction of alveolar clefts more than 4 years ago. Since then , more than 120 cleft patients have received MBGs for reconstruction of alveolar clefts in our center. Experience with this procedure was first gained in minor clefts, ie, cleft lip alveolar process only (CLA) patients with satisfactory results." Encouraged by these results, the indications have gradually been widened to include combined clefts of the lip and palate (UCLP). The aim of the present report is to describe our approach to the first 20 UCLP patients receiving the procedure and to compare the results of treatment
• Staff, Departmenl of Oral and Maxillofacial Surgery, Aarhus University Hospital, Aarhu s, Denmark . t Head, Aarhus Cleft Palate Institute, Aarhus, Denmark. Address correspondence and reprint requests to Dr SindetPedersen: Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Norrebrogade, DK·8000 Aarhus C, Denmark . © 1990 American Association of Oral and Maxillofacial Surgeons 0278·2391/90/4806-0003$3.0010
554
555
SINDET-PEDERSEN AND ENEMARK
Table 1. Baseline Variables
SCORE Iliac Crest Bone Grafts (n = 20)
Mandibular Bone Grafts (n = 20)
0% 25%
Age at surgery (yr, mo) Mean Range Observation period (mo) Mean Range No. of days hospitalized Mean
9,1 8.2-9.11
10,3 9.5-12.7
18 13-27
20 12-33
3.2
3.8
50% 75% 100%
in these 20 patients with 20 randomly selected UCLP patients receiving ICB grafts. Materials and Methods
The study includes 40 UCLP patients, 20 consecutive patients having reconstruction with MBG and 20 previously treated, randomly selected patients whose defects were reconstructed with ICB. The indications for surgery and our organization for treatment of cleft patients have been described previously.P'P The age at surgery, the postoperative observation period, and hospitalization period appear in Table 1. The prevalence of crossbites in the two groups is shown in Table 2. As an orthopedic effect upon the lesser maxillary segment is required, transverse expansion should be performed before much root resorption of the deciduous teeth has taken place. Timing of the bone grafting is also dependent on the presence or absence of a lateral incisor in the lesser maxillary segment. If grafting is done too early, there is an increased risk of canine retention in cases without a lateral incision to guide the eruption of the canine.P Incisor tilting and inversion of the cleft side central are not corrected before the alveolar process defect has been grafted, as correction before bone grafting often results in apical root resorption. Due to these considerations, orthodontic treatment is commenced at age 8 to 9 years. In the ICB group, transverse expansion of the maxilla was completed prior to surgery in all patients. The UCLP patients who were to receive mandibular bone grafts were selected following a clinical and radiologic examination demonstrating that there Table 2. Prevalence of Crossbites in the Two Groups of Patients
Mandibular bone grafts lliac crest bone grafts
FIGURE 1. The diagram illustrates the index used for scoring of marginal bone level on occlusal radiographs.
probably would be a sufficient amount of donor bone at the mandibular symphysis to reconstruct the alveolar process defect. To widen the application of the MBG procedure, transverse expansion was commenced but only partially fulfilled prior to surgery in order not to make the alveolar process defect too large. The patient was then referred for surgery at the appropriate time, and 2 to 3 months postoperatively maxillary expansion was continued. All patients underwent surgery under general anesthesia, received prophylactic antibiotics at surgery, and had preoperative mouth irrigation with 0.2% chlorhexidine. An acrylic plate to cover the hard palate was used in all patients.6-8,13,14 Almost all the patients had surgery using the flap design described by Krantz Simonsen.!" although a few patients with permanent teeth close to the cleft had the soft tissue approach described by Abyholm. 15 The bone grafts were obtained below the apices of the incisors through an intraoral approach; if necessary the lingual cortical bone plate in the area was also used, as previously described.f All postoperative evaluations were carried out by the orthodontists at the Aarhus Cleft Palate Institute during the continued orthodontic treatment. The marginal bone level on cleft-related teeth was assessed on intraoral films and quantitated as shown in Fig 1. On these films, the radiological appearance of the bone, presence of root resorptions, Table 3.
No Crossbite
Canine Only
Molar Crossbite
No.
Score
3 I
4 5
13 14
20 20
2
I
Marginal Bone Level Mandibular Bone Grafts (n = 20)
Iliac Crest Bone Grafts (n = 20)
16 4
15 5
556
MANDIBULAR BONE GRAFfS FOR ALVEOLAR CLEFfS
A
FIGURE 2. Clinical use of mandibular bone graft. A and B. The clinical appearance of a UCLP patient prior to expansion of the maxilla. C and D. Clinical and radiologic appearance prior to bone grafting with mandibular symphyseal bone. E. Radiograph shows the bone healing 6 months after bone grafting. F, G. and H. Clinical and radiologic appearance 18 months after bone grafting of the alveolar cleft with mandibular bone.
and retention of canines were examined. The clinical examination of the recipient site included measurement of periodontal pockets, assessment of the amount of attached gingiva, and evaluation of the morphology of the reconstructed alveolar process. The donor site was examined clinically for pulp necrosis, periodontal and soft tissue healing, and function of the mental nerve, and radiologically to assess bone healing and iatrogenic damage to roots. Furthermore, the appearance and function of the soft tissues in the lower lip were assessed. Results
In the immediate postoperative phase, all patients in the IBG group complained of pain from the donor site; the patients gained normal mobility within a few weeks after surgery. Patients receiving MBGs did not complain specifically of pain from the donor site. The marginal bone level (Table 3) was similar
in the two groups. External root resorption could not be detected in any of the patients. Retained canines were present in 15% of the patients in the MBG group and in 20% of the patients in the IBG group. No patients had pathological periodontal pockets, but the attached gingiva was evaluated as unsatisfactory in 25% of the patients in the MBG group and 30% of the patients in the IBG group. The morphology of the reconstructed alveolar process was considered as sufficient in all patients in both groups. A representative example of the result of treatment in one of the patients from the MBG group is shown in Fig 2. The donor sites in the MBG group showed radiologic evidence of healing within 6 months after surgery, as demonstrated in Fig 3. In all patients in the MBG group, the mentalis muscle reinserted in its previous position, giving a normal appearance and function of the lower lip within a few months. The only postoperative complication was seen in a pa-
SINDET-PEDERSEN AND ENEMARK
557
F
FIGURE 2 (cont'd),
tient receiving a mandibular bone graft where a partial dehiscence of the donor site developed. This dehiscence healed spontaneously after the patient continued chlorhexidine mouth rinses for 1 month. Discussion
The results of this study demonstrate that recon struction of alveolar clefts with MBG or ICB has a comparable prognosis. The age at surgery was lower in the patients receiving MBGs than in the patients treated with ICB grafts (Table 1). However, the age at surgery was in accord with previously reported recommendations7.8.12.13.15;18 showing that the best results are achieved when patients undergo surgery before eruption of the canine. The lower age in the MBG group of patients was due to the fact that we aimed at reducing the age at surgery to between 8 and 10 years to prolong the period when the patients can receive active orthodontic treatment to compensate for growth retardation induced by the surgical procedures." The minimum
follow-up period in the present investigation was 12 months, as it has been shown that the results of treatment in such patients do not show significant changes from 6 months after surgery to long-terril follow-up (more than 4 years)." The mandibular symphysis offers less donor bone than the iliac crest, for which reason not all cleft patients can have reconstruction with this ap proach. To extend the applicability of the procedure, and also to include patients with larger clefts, we therefore changed our preoperative orthodontic treatment so that transverse expansion of the maxilla was commenced only prior to surgery, reducing the amount of bone necessary to close the defect. Expansion was then continued 2 to 3 months after surgery, and was completed successfully in all patients. There is experimental evidence that intramembranous bone grafts maintain more of their volume'' and show less postoperative resorption'? than ICB grafts, which probably can be ascribed to more
558
MANDIBULAR BONE GRAFTS FOR ALVEOLAR CLEFTS
FIGURE 3. Healing of mandibular donor site. A, Lateral radiograph demonstrates the donor site on the mandibular symphysis immediately after surgery. B, Radiograph 6 months after bone grafting shows healing of the donor site. C, Radiograph shows the healed donor site 2 years after surgery.
rapid revascularization of the intramembranous bone grafts. II In accordance with these experimental data, it is our impression that the cleft defects can be successfully treated with less bone when intramembranous bone is used as compared with iliac crest bone. By. careful timing of the surgery to utilize the bone-inducing capacity of erupting teeth (ie, the canine) and employing an active orthodontic approach, bone grafting as such becomes a less important decisive factor for the outcome of treatment. Whether intramembranous bone as compared with enchondral bone offers other advantages due to its embryologic similarity with the recipient site cannot be answered yet, but further studies are in progress. The clinical advantages of using MBGs in these patients are obvious. The. operating time and thus anaesthetic time is significantly reduced by the easier access to the donor site, and thus the postoperative morbidity is reduced. It has previously been shown that a donor site at the iliac crest results in some morbidity, 19 and not infrequently patients develop unpleasant scarring. These problems can be avoided using mandibular bone. Furthermore, operating exclusively intraorally was experienced as less extensive surgery by patients (and parents) as compared with using the iliac crest as a donor site. We therefore conclude that the mandibular symphysis constitutes an advantageous alternative to the iliac crest as a donor site' for bone grafts to reconstruct alveolar clefts. References I. Witsenburg B: The reconstruction of anterior residual bone defects in palients with cleft lip, alveolus and palate. A Review. J Maxillofac Surg 13:197, 1985 2. Bosker H, van Oijk L: Het bottransplantaat uit de mandibula voor herstel van de gnatho-palatoschisis. Ned Tijdschr Tandheelk 87:383, 1980
3. Edwab RR, Roberts MJ, Solems J, et al: Autogenous calvarial bone dust for mandibular reconstruction. J Oral MaxiIIofac Surg 40:313, 1982 4. Wolfe SA, Berkowitz SB: The use of cranial bone grafts in the closure of alveolar and anterior palatal defects. Plast Reconstr Surg 72:659, 1983 5. Harsha BC, Turvey TA, Powers SK: Use of autogenous cranial bone grafts in maxillofacial surgery: A preliminary report. J Oral Maxillofac Surg 44:11, 1986 6. Sindet-Pedersen S, Enemark H: Mandibular bone grafts for reconstruction of alveolar clefts. J Oral Maxillofac Surg 46:533, 1988
7. Sindet-Pedersen S, Enemark H: Comparative study of secondary and late secondary bone grafting in patients with residual cleft defects. Short term evaluation. Int J Oral Surg 14:389, 1985 8. Enemark H, Sindet-Pedersen S, Bundgaard M: Long-term results of secondary bone grafting of alveolar clefts. J Oral Maxillofac Surg 45:913, 1987 9. Smith JO, Abramson M: Membraneous vs endochondral bone autografts. Arch Otolaryngol 99:203, 1974 10. Zins JE, Whitaker LA: Membraneous vs endochondral bone autografts: Implications for craniofacial reconstruction. Surg Forum 30:521, 1979 II. Kusiak JF, Zins JE, Whitaker LA: The early revascularization of membraneous bone. Plast Reconstr Surg 76:510, 1985 12. Enemark H, Krantz Simonsen E, Schramm J: Secondary
bone grafting in unilateral cleft lip palate patients: Indications and treatment procedure. Int J Oral Surg 14:2, 1985 13. Enemark H, Sindet-Pedersen S, Bundgaard M, et al: Combined orthodontic-surgical treatment of alveolar clefts. Ann Plast Surg 21:127, 1988 14. Krantz Simonsen E: Secondary bone grafting for repair of residual cleft defects in the alveolar process and hard palate. A new surgical technique. Int J Oral Maxillofac Surg 15:I, 1986 15. Abyholm FE, Bergland 0, Semb G: Secondary bone grafting of alveolar clefts. Scand J Plast Reconstr Surg 15:127, 1981 16. Boyne PJ, Sands NR: Secondary bone grafting of residual alveolar and palatal clefts. Oral Surg 30:87, 1972 17. El Oeeb M, MesserLB, Lehnert MW, et al: Canine eruption
into grafted bone in maxillary alveolar cleft defects. Cleft Palate J 19:9, 1982 18. Bergland 0, Semb G, Abyholm FE: Elimination of the residual alveolar cleft by secondary bone grafting and subsequent orthodontic treatment. Cleft Palate J 23: 175, 1986 19. Marx RE, Morales MJ: Morbidity from bone harvest in major jaw reconstruction. J Oral Maxillofac Surg 46:196, 1988
RTICL
J Oral Maxillofac Su,g 48 :554-558. 1990
Reconstruction of Alveolar Clefts With Mandibular or Iliac Crest Bone Grafts: A Comparative Study STEEN SINDET-PEDERSEN, DDS,· AND HANS ENEMARK, DDSt The aim of this study was to compare the results of treatment obtained with mandibular symphyseal and iliac crest bone grafts used for reconstruction of alveolar clefts. The study included 40 patients with unilateral cleft lip palate (UCLP): 20 consecutive patients whose defects were reconstructed with mandibular bone grafts (MBG) and 20 randomly selected UCLP patients who underwent reconstruction with iliac crest bone (ICB). The age at surgery varied from 8 to 13 years (mean age MBG group, 9.1 years; ICB group, 10.3 years), and the postoperative observation period varied from 12 to 33 months (mean, 19 months). Transverse expansion of the maxilla was not completed until after the bone grafting in the group of patients receiving MBGs, whereas it was completed before surgery in the ICB group. The observed marginal bone level on cleft-related teeth was similar in both groups. No periodontal complications were present in any of the patients, and the amount of attached gingiva was similar in both groups. In the MBG group, 15% of the canines were retained, whereas 20% of the canines were retained in the ICB group. The only complication that developed was in a patient from the MBG group, in whom a partial dehiscence of the donor site was observed. The results of this study demonstrate that reconstruction of alveolar clefts with MBG or ICB has a comparable prognosis. The use of MBGs in these patients has several advantages compared with ICB, including reduced operating time, reduced morbidity, reduced hospitalization time, and finally, a cutaneous scar at the iliac crest can be avoided.
Reconstruction of alveolar process defects in cleft patients with bone grafts is a well documented and commonly used procedure. The iliac crest has been the preferred donor site in most centers,' but recently the use of intramembranous bone grafts has gained increasing attention in the literature.F" Iliac crest bone (ICB) grafts have been used in our
center for alveolar cleft reconstruction since 1972 with satisfactory results.I-" However, due to the easier access to the donor site using mandibular bone grafts (MBGs) and the tendency of intramembranous bone grafts to maintain more of their volume than enchondral bone grafts ,9 -1 1 we started using MBGs for reconstruction of alveolar clefts more than 4 years ago. Since then , more than 120 cleft patients have received MBGs for reconstruction of alveolar clefts in our center. Experience with this procedure was first gained in minor clefts, ie, cleft lip alveolar process only (CLA) patients with satisfactory results." Encouraged by these results, the indications have gradually been widened to include combined clefts of the lip and palate (UCLP). The aim of the present report is to describe our approach to the first 20 UCLP patients receiving the procedure and to compare the results of treatment
• Staff, Departmenl of Oral and Maxillofacial Surgery, Aarhus University Hospital, Aarhu s, Denmark . t Head, Aarhus Cleft Palate Institute, Aarhus, Denmark. Address correspondence and reprint requests to Dr SindetPedersen: Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Norrebrogade, DK·8000 Aarhus C, Denmark . © 1990 American Association of Oral and Maxillofacial Surgeons 0278·2391/90/4806-0003$3.0010
554
555
SINDET-PEDERSEN AND ENEMARK
Table 1. Baseline Variables
SCORE Iliac Crest Bone Grafts (n = 20)
Mandibular Bone Grafts (n = 20)
0% 25%
Age at surgery (yr, mo) Mean Range Observation period (mo) Mean Range No. of days hospitalized Mean
9,1 8.2-9.11
10,3 9.5-12.7
18 13-27
20 12-33
3.2
3.8
50% 75% 100%
in these 20 patients with 20 randomly selected UCLP patients receiving ICB grafts. Materials and Methods
The study includes 40 UCLP patients, 20 consecutive patients having reconstruction with MBG and 20 previously treated, randomly selected patients whose defects were reconstructed with ICB. The indications for surgery and our organization for treatment of cleft patients have been described previously.P'P The age at surgery, the postoperative observation period, and hospitalization period appear in Table 1. The prevalence of crossbites in the two groups is shown in Table 2. As an orthopedic effect upon the lesser maxillary segment is required, transverse expansion should be performed before much root resorption of the deciduous teeth has taken place. Timing of the bone grafting is also dependent on the presence or absence of a lateral incisor in the lesser maxillary segment. If grafting is done too early, there is an increased risk of canine retention in cases without a lateral incision to guide the eruption of the canine.P Incisor tilting and inversion of the cleft side central are not corrected before the alveolar process defect has been grafted, as correction before bone grafting often results in apical root resorption. Due to these considerations, orthodontic treatment is commenced at age 8 to 9 years. In the ICB group, transverse expansion of the maxilla was completed prior to surgery in all patients. The UCLP patients who were to receive mandibular bone grafts were selected following a clinical and radiologic examination demonstrating that there Table 2. Prevalence of Crossbites in the Two Groups of Patients
Mandibular bone grafts lliac crest bone grafts
FIGURE 1. The diagram illustrates the index used for scoring of marginal bone level on occlusal radiographs.
probably would be a sufficient amount of donor bone at the mandibular symphysis to reconstruct the alveolar process defect. To widen the application of the MBG procedure, transverse expansion was commenced but only partially fulfilled prior to surgery in order not to make the alveolar process defect too large. The patient was then referred for surgery at the appropriate time, and 2 to 3 months postoperatively maxillary expansion was continued. All patients underwent surgery under general anesthesia, received prophylactic antibiotics at surgery, and had preoperative mouth irrigation with 0.2% chlorhexidine. An acrylic plate to cover the hard palate was used in all patients.6-8,13,14 Almost all the patients had surgery using the flap design described by Krantz Simonsen.!" although a few patients with permanent teeth close to the cleft had the soft tissue approach described by Abyholm. 15 The bone grafts were obtained below the apices of the incisors through an intraoral approach; if necessary the lingual cortical bone plate in the area was also used, as previously described.f All postoperative evaluations were carried out by the orthodontists at the Aarhus Cleft Palate Institute during the continued orthodontic treatment. The marginal bone level on cleft-related teeth was assessed on intraoral films and quantitated as shown in Fig 1. On these films, the radiological appearance of the bone, presence of root resorptions, Table 3.
No Crossbite
Canine Only
Molar Crossbite
No.
Score
3 I
4 5
13 14
20 20
2
I
Marginal Bone Level Mandibular Bone Grafts (n = 20)
Iliac Crest Bone Grafts (n = 20)
16 4
15 5
556
MANDIBULAR BONE GRAFfS FOR ALVEOLAR CLEFfS
A
FIGURE 2. Clinical use of mandibular bone graft. A and B. The clinical appearance of a UCLP patient prior to expansion of the maxilla. C and D. Clinical and radiologic appearance prior to bone grafting with mandibular symphyseal bone. E. Radiograph shows the bone healing 6 months after bone grafting. F, G. and H. Clinical and radiologic appearance 18 months after bone grafting of the alveolar cleft with mandibular bone.
and retention of canines were examined. The clinical examination of the recipient site included measurement of periodontal pockets, assessment of the amount of attached gingiva, and evaluation of the morphology of the reconstructed alveolar process. The donor site was examined clinically for pulp necrosis, periodontal and soft tissue healing, and function of the mental nerve, and radiologically to assess bone healing and iatrogenic damage to roots. Furthermore, the appearance and function of the soft tissues in the lower lip were assessed. Results
In the immediate postoperative phase, all patients in the IBG group complained of pain from the donor site; the patients gained normal mobility within a few weeks after surgery. Patients receiving MBGs did not complain specifically of pain from the donor site. The marginal bone level (Table 3) was similar
in the two groups. External root resorption could not be detected in any of the patients. Retained canines were present in 15% of the patients in the MBG group and in 20% of the patients in the IBG group. No patients had pathological periodontal pockets, but the attached gingiva was evaluated as unsatisfactory in 25% of the patients in the MBG group and 30% of the patients in the IBG group. The morphology of the reconstructed alveolar process was considered as sufficient in all patients in both groups. A representative example of the result of treatment in one of the patients from the MBG group is shown in Fig 2. The donor sites in the MBG group showed radiologic evidence of healing within 6 months after surgery, as demonstrated in Fig 3. In all patients in the MBG group, the mentalis muscle reinserted in its previous position, giving a normal appearance and function of the lower lip within a few months. The only postoperative complication was seen in a pa-
SINDET-PEDERSEN AND ENEMARK
557
F
FIGURE 2 (cont'd),
tient receiving a mandibular bone graft where a partial dehiscence of the donor site developed. This dehiscence healed spontaneously after the patient continued chlorhexidine mouth rinses for 1 month. Discussion
The results of this study demonstrate that recon struction of alveolar clefts with MBG or ICB has a comparable prognosis. The age at surgery was lower in the patients receiving MBGs than in the patients treated with ICB grafts (Table 1). However, the age at surgery was in accord with previously reported recommendations7.8.12.13.15;18 showing that the best results are achieved when patients undergo surgery before eruption of the canine. The lower age in the MBG group of patients was due to the fact that we aimed at reducing the age at surgery to between 8 and 10 years to prolong the period when the patients can receive active orthodontic treatment to compensate for growth retardation induced by the surgical procedures." The minimum
follow-up period in the present investigation was 12 months, as it has been shown that the results of treatment in such patients do not show significant changes from 6 months after surgery to long-terril follow-up (more than 4 years)." The mandibular symphysis offers less donor bone than the iliac crest, for which reason not all cleft patients can have reconstruction with this ap proach. To extend the applicability of the procedure, and also to include patients with larger clefts, we therefore changed our preoperative orthodontic treatment so that transverse expansion of the maxilla was commenced only prior to surgery, reducing the amount of bone necessary to close the defect. Expansion was then continued 2 to 3 months after surgery, and was completed successfully in all patients. There is experimental evidence that intramembranous bone grafts maintain more of their volume'' and show less postoperative resorption'? than ICB grafts, which probably can be ascribed to more
558
MANDIBULAR BONE GRAFTS FOR ALVEOLAR CLEFTS
FIGURE 3. Healing of mandibular donor site. A, Lateral radiograph demonstrates the donor site on the mandibular symphysis immediately after surgery. B, Radiograph 6 months after bone grafting shows healing of the donor site. C, Radiograph shows the healed donor site 2 years after surgery.
rapid revascularization of the intramembranous bone grafts. II In accordance with these experimental data, it is our impression that the cleft defects can be successfully treated with less bone when intramembranous bone is used as compared with iliac crest bone. By. careful timing of the surgery to utilize the bone-inducing capacity of erupting teeth (ie, the canine) and employing an active orthodontic approach, bone grafting as such becomes a less important decisive factor for the outcome of treatment. Whether intramembranous bone as compared with enchondral bone offers other advantages due to its embryologic similarity with the recipient site cannot be answered yet, but further studies are in progress. The clinical advantages of using MBGs in these patients are obvious. The. operating time and thus anaesthetic time is significantly reduced by the easier access to the donor site, and thus the postoperative morbidity is reduced. It has previously been shown that a donor site at the iliac crest results in some morbidity, 19 and not infrequently patients develop unpleasant scarring. These problems can be avoided using mandibular bone. Furthermore, operating exclusively intraorally was experienced as less extensive surgery by patients (and parents) as compared with using the iliac crest as a donor site. We therefore conclude that the mandibular symphysis constitutes an advantageous alternative to the iliac crest as a donor site' for bone grafts to reconstruct alveolar clefts. References I. Witsenburg B: The reconstruction of anterior residual bone defects in palients with cleft lip, alveolus and palate. A Review. J Maxillofac Surg 13:197, 1985 2. Bosker H, van Oijk L: Het bottransplantaat uit de mandibula voor herstel van de gnatho-palatoschisis. Ned Tijdschr Tandheelk 87:383, 1980
3. Edwab RR, Roberts MJ, Solems J, et al: Autogenous calvarial bone dust for mandibular reconstruction. J Oral MaxiIIofac Surg 40:313, 1982 4. Wolfe SA, Berkowitz SB: The use of cranial bone grafts in the closure of alveolar and anterior palatal defects. Plast Reconstr Surg 72:659, 1983 5. Harsha BC, Turvey TA, Powers SK: Use of autogenous cranial bone grafts in maxillofacial surgery: A preliminary report. J Oral Maxillofac Surg 44:11, 1986 6. Sindet-Pedersen S, Enemark H: Mandibular bone grafts for reconstruction of alveolar clefts. J Oral Maxillofac Surg 46:533, 1988
7. Sindet-Pedersen S, Enemark H: Comparative study of secondary and late secondary bone grafting in patients with residual cleft defects. Short term evaluation. Int J Oral Surg 14:389, 1985 8. Enemark H, Sindet-Pedersen S, Bundgaard M: Long-term results of secondary bone grafting of alveolar clefts. J Oral Maxillofac Surg 45:913, 1987 9. Smith JO, Abramson M: Membraneous vs endochondral bone autografts. Arch Otolaryngol 99:203, 1974 10. Zins JE, Whitaker LA: Membraneous vs endochondral bone autografts: Implications for craniofacial reconstruction. Surg Forum 30:521, 1979 II. Kusiak JF, Zins JE, Whitaker LA: The early revascularization of membraneous bone. Plast Reconstr Surg 76:510, 1985 12. Enemark H, Krantz Simonsen E, Schramm J: Secondary
bone grafting in unilateral cleft lip palate patients: Indications and treatment procedure. Int J Oral Surg 14:2, 1985 13. Enemark H, Sindet-Pedersen S, Bundgaard M, et al: Combined orthodontic-surgical treatment of alveolar clefts. Ann Plast Surg 21:127, 1988 14. Krantz Simonsen E: Secondary bone grafting for repair of residual cleft defects in the alveolar process and hard palate. A new surgical technique. Int J Oral Maxillofac Surg 15:I, 1986 15. Abyholm FE, Bergland 0, Semb G: Secondary bone grafting of alveolar clefts. Scand J Plast Reconstr Surg 15:127, 1981 16. Boyne PJ, Sands NR: Secondary bone grafting of residual alveolar and palatal clefts. Oral Surg 30:87, 1972 17. El Oeeb M, MesserLB, Lehnert MW, et al: Canine eruption
into grafted bone in maxillary alveolar cleft defects. Cleft Palate J 19:9, 1982 18. Bergland 0, Semb G, Abyholm FE: Elimination of the residual alveolar cleft by secondary bone grafting and subsequent orthodontic treatment. Cleft Palate J 23: 175, 1986 19. Marx RE, Morales MJ: Morbidity from bone harvest in major jaw reconstruction. J Oral Maxillofac Surg 46:196, 1988
