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Prevalence of infection with the use of β-tricalcium phosphate as a bone graft substitute during Le Fort I osteotomy
Int. J. Oral Maxillofac. Surg. 2017; 46: 62–66 http://dx.doi.org/10.1016/j.ijom.2016.10.001, available online at http://www.sciencedirect.com
Clinical Paper Orthognathic Surgery
Prevalence of infection with the use of b-tricalcium phosphate as a bone graft substitute during Le Fort I osteotomy
M. Ragaey1,2, J. E. Van Sickels1 1
Division of Oral and Maxillofacial Surgery, Chandler Medical Center, University of Kentucky, Lexington, KY, USA; 2ESHA Oral and Cranio-maxillofacial Surgery Center, Agouza, Cairo, Egypt
M. Ragaey, J.E. Van Sickels: Prevalence of infection with the use of b-tricalcium phosphate as a bone graft substitute during Le Fort I osteotomy. Int. J. Oral Maxillofac. Surg. 2017; 46: 62–66. # 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Abstract. While grafting with bone substitutes has been shown to provide greater stability in maxillary advancements, infection remains a concern with any material that is placed in close proximity to the maxillary sinus. The purpose of this study was to evaluate the prevalence of infection in maxillary advancements in which a bone graft substitute (b-tricalcium phosphate; b-TCP) was placed at the time of surgery. This was a retrospective study of all maxillary osteotomies. Patients were divided into two groups: group 1 included maxillary osteotomies in which b-TCP was not used; group 2 included any maxillary osteotomy where b-TCP was used. The prevalence of infection, slow healing, and need for second surgery due to infection or non union was noted. Fisher’s exact test was used to compare differences between the groups. Records were adequate for 438 patients: group 1 included 297 patients, while group 2 included 141. No infections were noted in either group. In group 2, there was one patient who had delayed union/non-union requiring a second procedure. Statically, there was no significant difference between the two groups (P = 0.3219). Based on the data obtained in this study, the use of b-TCP does not increase the incidence of infection or complications when used in Le Fort I maxillary osteotomy.
Introduction
Interpositional bone grafts have been used with maxillary osteotomies for many years. Bone grafts and/or their substitutes can act as mechanical stops reducing relapse, provide a scaffold for bone to grow 0901-5027/01062 + 05
over, and prevent soft tissue herniation or growth into osteotomy sites.1–4 Several authors consider that maxillary advancement of more than 4 mm is problematic in terms of relapse.5,6 Waite et al. compared the stability of large advancements with and without genial bone grafts. They noted
Key words: orthognathic surgery; maxillary advancement; Le Fort I; b-tricalcium phosphate; b-TCP; infection.. Accepted for publication 6 October 2016 Available online 6 November 2016
that the patients who received grafts showed greater stability than those who were not grafted.5 While autologous bone grafting still plays a significant role in clinical practice, many substitutes have been developed to decrease the morbidity associated with
# 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Infection with the use of b-TCP for grafting donor sites.1,7–11 Allografts are a biological alternative to autologous grafts, but they carry a small and real risk of transmission of disease.7,12–14 In contrast, btricalcium phosphate (b-TCP), a synthetic calcium phosphate ceramic, also allows bony regeneration and substitution of bone, but without the risk of disease transmission.13,15,16 It is a biocompatible and absorbable material. The mechanism of bone formation following it use is osteoconduction.8,9 The use of b-TCP as an alternative to traditional bone grafting avoids donor site morbidity and saves time in the operating room. While b-TCP has been shown to be safe, infection remains a concern with any alloplastic material that is placed in close proximity to the maxillary sinus.4 Cottrell and Wolford assessed 245 consecutive patients who had coralline hydroxyapatite placed during orthognathic surgery.4 Of 207 implants that were placed along the lateral sinus wall, 198 remained long term. For the last 6 years, b-TCP (ChronOS; Depuy Synthes, West Chester, PA, USA) has been used routinely to graft maxillary osteotomy sites at the present authors’ institution. In contrast to coralline hydroxyapatite, it is easier to contour and is resorbed in 6–18 months.17,18 The purpose of this retrospective study was to determine the prevalence of infection or delayed healing following the use of bTCP in maxillary osteotomies. Materials and methods
All maxillary orthognathic surgeries done in the department of oral and maxillofacial surgery of the study institution between January 2009 and June 2015 were reviewed. The records were inspected for infection, slow healing, and the need for a second operation. Two groups of patients were selected: group 1 comprised patients for whom b-TCP was not used during the osteotomy (control group), and group 2 included patients in whom b-TCP was used during the osteotomy. Group 2 included maxillary advancements of 4 mm in which b-TCP was wedged between the advanced maxilla and the residual skeletal base, as well as segmented maxillary osteotomies in which b-TCP was wedged between the segments. In both cases, the b-TCP was in close proximity to the maxillary sinus. The patients in group 2 were sub-divided into two groups: one-piece and multiple-piece maxillary osteotomies. The one-piece maxillary osteotomies were further divided into three subgroups according to the degree of advancement:
63
Table 1. Distribution of patients in group 2 (b-TCP used following osteotomy). One-piece maxillary osteotomy* Minor (<5 mm) Medium (5–8 mm) Major (>8 mm) Multiple-piece maxillary osteotomy
Number of cases
Percentage
0 28 43 70
0% 19.9% 30.5% 49.6%
b-TCP, b-tricalcium phosphate. * Patients in the one-piece maxillary osteotomy group were further divided into three subgroups according to the degree of advancement.
minor advancement (<5 mm), medium (5– 8 mm), and major advancement (>8 mm). The segmental osteotomies consisted of two- and three-piece maxillary osteotomies in which b-TCP was used to fill the interdental gaps (Table 1) . For group 1, the inclusion criteria were Le Fort I osteotomy in one or more pieces where b-TCP was not used; complete records; follow-up of 6 months. Exclusion criteria were incomplete follow-up data; use of any grafting material; syndromic patients; patients with cleft lip and palate; previous surgery; a history of trauma. For group 2, the inclusion criteria were one-piece Le Fort I osteotomy with 4 mm advancement, or segmental Le Fort I osteotomy; use of b-TCP in the osteotomy gap; follow-up of 6 months. Exclusion criteria were incomplete follow-up data; use of other grafting materials; syndromic patients; patients with cleft lip and palate; previous surgery; a history of trauma. Fisher’s exact test was used to compare differences between the groups, with significance set at a P 0.05.
b-Tricalcium phosphate bone graft substitute
ChronOS bone graft substitute (Depuy Synthes) is a synthetic b-TCP bone void filler; it is radiopaque, resorbable, and osteoconductive. The material contains calcium and phosphorus and it is resorbed and replaced by bone in 6–18 months.18 It has a similar radiopacity to bone; thus bTCP is frequently difficult to identify in two-dimensional images. Fig. 1 shows a cone beam computed tomography (CBCT) scan obtained immediately postoperative for a Le Fort I advancement case in which b-TCP was used. Fig. 2 shows a CBCT scan obtained at 6 months after surgery; the b-TCP has been resorbed and replaced by bone.
Technique
All Le Fort I osteotomies were performed in a similar fashion.6 In the control group, the maxilla was moved in a variety of directions, but b-TCP was not used as an adjunctive material. In group 2, after the maxilla had been advanced to the
Fig. 1. CBCT obtained immediately postoperative showing the interpositional b-TCP on the lateral and anterior walls of the maxillary osteotomy.
64
Ragaey and Van Sickels Results
Fig. 2. CBCT obtained at 6 months postoperative for a patient who underwent Le Fort I advancement with the use of b-TCP as a bone substitute in the osteotomy. The b-TCP has been completely resorbed and complete bone healing has occurred.
Fig. 3. b-TCP wedges can easily be carved to fit the osteotomy gaps using a No. 15 Bard Parker blade.
desired position, bone plates were used to fix the segments. b-TCP was contoured with a number 15 Bard Parker blade (Fig. 3) and wedged into any gaps 4 mm in size, ensuring contact with the bony segments (Fig. 4). The material is brittle, but it can easily be carved with a number 15 scalpel blade. In segmental Le Fort I osteotomies, the material was
wedged into the interdental gaps after the fabricated splint was ligated to the segments prior to the maxilla being fixed. The segments were gently pried apart with a periosteal elevator to allow the material to be held firmly once the periosteal elevator was removed. This study was approved by the necessary institutional review board.
The records of 457 patients who had undergone a Le Fort I maxillary osteotomy were reviewed. Four hundred and thirtyeight patients had complete records (at least 6 months of follow-up). These patients were divided into two groups: group 1 (control) in which no graft was used (n = 297), and group 2 in which bTCP was used (n = 141) (Table 1). All had undergone a Le Fort I osteotomy (onepiece or multiple segment) with or without b-TCP bone substitute. There were no infections in either group (Table 2). Of the 141 patients in group 2, one patient had delayed union/non union. There was no statistically significant difference between the two groups (P = 0.3219). The patient who required second surgery had undergone a large advancement (8 mm) and admitted to smoking postoperatively. A few weeks after surgery it was noted that the maxilla was mobile. The patient was followed for 5 months, at which point it was noted that the maxilla was firm but had healed in a malocclusion (Fig. 5). In terms of the advancement, none of the study patients in group 2 had a minor advancement (<5 mm), 19.9% had a medium advancement (5–8 mm), and 30.5% had a major advancement (>8 mm). Multiple-piece osteotomies (two- and threepiece maxillary osteotomies, with b-TCP just filling the interdental gaps) accounted for the largest group at 49.6% (Table 1). Details of the follow-up periods and complications are presented in Table 2.
Discussion
Infection was chosen as an outcome measure in this study, as this is usually well documented in the patient records and can have devastating results following elective osteotomy. There was no record of an episode of infection in either study group.
Table 2. Follow-up and complications in the two study groups.*.
Follow-up period Complications Infection Need for a second surgery
Fig. 4. b-TCP placed in the osteotomy gap near the piriform aperture of a large maxillary advancement.
Group 1 (n = 297)
Group 2 (n = 141)
6 months to 6 years 0% 0% 0%
6 months to 6 years 0.7% 0% 0.7%
* Group 1 comprised patients for whom bTCP was not used during the osteotomy (control group); group 2 included patients in whom b-TCP was used during the osteotomy.
Infection with the use of b-TCP for grafting
65
Fig. 5. (a) Large maxillary advancement with smaller setback, which ultimately ended in a non union. (b) Five months later, the patient showed non union with a 4-mm relapse of the maxilla.
One of the problems associated with large advancement of the maxilla (4 mm) is relapse.5,6 Grafting osteotomy sites has been shown to prevent or minimize relapse in multiple studies.19– 21 While bone grafts have been used for years, the morbidity at the donor site and the additional time taken to obtain the graft are well known.1–3,18 The rationale for using a bone substitute is to decrease the time in the operating room and to decrease the patient’s discomfort. Lye et al. used demineralized bone to fill the voids following maxillary advancements of 4 mm in 61 patients.1 They noted a 3.3% incidence of maxillary sinusitis in this group and 8% incidence in patients who had other graft materials. Sinusitis was not recorded in the patient groups in the present study. All of the patients were prescribed antibiotics and decongestants after surgery. While sinusitis may have occurred in some of the subjects, it was not recorded in the charts. Cottrell and Wolford used coralline hydroxyapatite in a manner very similar to how b-TCP was used in the present study.4 They did not lose any coralline hydroxyapatite implants that were placed interdentally, but lost seven that were placed between palatine sites and nine along the lateral sinus wall. Infection was not seen in either of the two groups in the present study, nor was there any loss of the implants that were placed. b-TCP has been used in sinus lifts by itself and in combination with other material.18,22 In this application there is formation of bone, and infection does not appear to be a problem.
In this study there was one case of delayed union/non union in a large advancement (Fig. 5). The patient was a 19year-old male who admitted to smoking. Cigarette smoking is known to impede bone healing.23 It is also known to be a risk factor for postoperative complications.23–25 Whether the patient’s smoking habit was the reason for the difficulty with healing is unknown. Interestingly, Cottrell and Wolford lost nine implants that were placed in the lateral maxillary wall in three patients, and two of the three were smokers.4 No other complications were documented in either of the groups of patients in the present study. A weakness of this study is that it was retrospective in design. A strength is that it represents a large number of patients treated over a considerable period of time, all treated by the same surgeon. The b-TCP material comes in blocks or wedges, and although brittle, it is relatively easy to carve (Fig. 3) and to adapt to osteotomy sites. The time required to place it is about 10 min. This is considerably less than the time that it takes to obtain a graft from another site and fashion it to fit an osteotomy gap. Currently, there appears to be no study reported in the literature that has examined the prevalence of infection following the use of b-TCP in maxillary surgery. The results of this study indicate that the use of b-TCP as a bone graft substitute is safe, with a minimal prevalence of infection and dehiscence compared to allografts.1,12,14,26 There was no evidence of rejection and it appears that b-TCP is completely resorbed and replaced by bone over a period of 18 months. Thus b-TCP
can safely be used as a bone graft substitute in Le Fort I osteotomies to fill the osseous voids when the maxilla is advanced or segmented. Funding
None. Competing interests
None. Ethical approval
This study was approved by the Institutional Review Board of the University of Kentucky (approval number 16-0054X2B). Patient consent
No clinical photographs are included. This was a retrospective study and qualified for a waiver of informed consent as per the Institutional Review Board. Acknowledgements. The authors would like to express their gratitude to Christina Lewis, clinic manager of the Oral and Maxillofacial Surgery Division, College of Dentistry, University of Kentucky, Lexington, Kentucky, for her help with the medical records.
References 1. Lye KW, Deatherage JR, Waite PD. The use of demineralized bone matrix for grafting during Le Fort I and chin osteotomies:
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Ragaey and Van Sickels techniques and complications. J Oral Maxillofac Surg 2008;66:1580–5. Epker BN, Schendel SA. Total maxillary surgery. Int J Oral Surg 1980;9:1–24. Araujo A, Schendel SA, Wolford LM, Epker BN. Total maxillary advancement with and without bone grafting. J Oral Surg 1978;36:849–58. Cottrell DA, Wolford LM. Long-term evaluation of the use of coralline hydroxyapatite in orthognathic surgery. J Oral Maxillofac Surg 1998;56:935–41. [discussion 941–942]. Waite PD, Tejera TJ, Anucul B. The stability of maxillary advancement using Le Fort I osteotomy with and without genial bone grafting. Int J Oral Maxillofac Surg 1996;25:264–7. Bothur S, Blomqvist JE, Isaksson S. Stability of Le Fort I osteotomy with advancement: a comparison of single maxillary surgery and a two-jaw procedure. J Oral Maxillofac Surg 1998;56:1029–33. [discussion 1033–1024]. Ngo LT, Bruhn R, Custer B. Risk perception and its role in attitudes toward blood transfusion: a qualitative systematic review. Transfus Med Rev 2013;27:119–28. Rodella LF, Favero G, Labanca M. Biomaterials in maxillofacial surgery: membranes and grafts. Int J Biomed Sci 2011;7:81–8. Hirota M, Matsui Y, Mizuki N, Kishi T, Watanuki K, Ozawa T, et al. Combination with allogenic bone reduces early absorption of beta-tricalcium phosphate (beta-TCP) and enhances the role as a bone regeneration scaffold. Experimental animal study in rat mandibular bone defects. Dent Mater J 2009;28:153–61. Greenwald AS, Boden SD, Goldberg VM, Khan Y, Laurencin CT, Rosier RN. The committee on biological implants. Bonegraft substitutes: facts, fictions, and applications. J Bone Joint Surg Am 2001;83A(Suppl 2 Pt 2):98–103. Rueger JM, Linhart W, Sommerfeldt D. Biologic reactions to calcium phosphate ce-
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ramic implantations. Results of animal experiments. Orthopade 1998;27:89–95. Mankin HJ, Hornicek FJ, Raskin KA. Infection in massive bone allografts. Clin Orthop Relat Res 2005;(432):210–6. Mayr HO, Suedkamp NP, Hammer T, Hein W, Hube R, Roth PV, et al. b-Tricalcium phosphate for bone replacement: stability and integration in sheep. J Biomech 2015;48:1023–31. Delloye C, Cornu O, Druez V, Barbier O. Bone allografts: what they can offer and what they cannot. J Bone Joint Surg Br 2007;89:574–9. Chazono M, Tanaka T, Komaki H, Fujii K. Bone formation and bioresorption after implantation of injectable beta-tricalcium phosphate granules–hyaluronate complex in rabbit bone defects. J Biomed Mater Res A 2004;70:542–9. Ndiaye M, Terranova L, Mallet R, Mabilleau G, Chappard D. Three-dimensional arrangement of beta-tricalcium phosphate granules evaluated by microcomputed tomography and fractal analysis. Acta Biomater 2015;11:404–11. Damien E, Revell PA. Coralline hydroxyapatite bone graft substitute: a review of experimental studies and biomedical applications. J Appl Biomater Biomech 2004;2:65–73. Gorla LF, Spin-Neto R, Boos FB, Pereira Rdos S, Garcia-Junior IR, Hochuli-Vieira E. Use of autogenous bone and beta-tricalcium phosphate in maxillary sinus lifting: a prospective, randomized, volumetric computed tomography study. Int J Oral Maxillofac Surg 2015;44:1486–91. Luyk NH, Ward-Booth RP. The stability of Le Fort I advancement osteotomies using bone plates without bone grafts. J Maxillofac Surg 1985;13:250–3. Obwegeser HL. Surgical correction of small or retrodisplaced maxillae. The dish-face deformity. Plast Reconstr Surg 1969;43:351–65.
21. Welch TB. Stability in the correction of dentofacial deformities: a comprehensive review. J Oral Maxillofac Surg 1989;47:1142–9. 22. Somanathan RV, Simunek A. Evaluation of the success of beta-tricalcium phosphate and deproteinized bovine bone in maxillary sinus augmentation using histomorphometry: a review. Acta Medica (Hradec Kralove) 2006;49:87–9. 23. W-Dahl A, Toksvig-Larsen S. Cigarette smoking delays bone healing: a prospective study of 200 patients operated on by the hemicallotasis technique. Acta Orthop Scand 2004;75:347–51. 24. Moller AM, Villebro N, Pedersen T, Tonnesen H. Effect of preoperative smoking intervention on postoperative complications: a randomised clinical trial. Lancet 2002;359:114–7. 25. Moller AM, Pedersen T, Villebro N, Munksgaard A. Effect of smoking on early complications after elective orthopaedic surgery. J Bone Joint Surg Br 2003;85:178–81. 26. Delloye C, De Halleux J, Cornu O, Wegmann E, Buccafusca GC, Gigi J. Organizational and investigational aspects of bone banking in Belgium. Acta Orthop Belg 1991;57(Suppl 2):27–34.
Address: Marwa Ragaey Division of Oral and Maxillofacial Surgery Chandler Medical Center University of Kentucky 800 Rose Street Lexington KY 40536-0297 USA Tel: +1 347 331 1119; Fax: +1 859 323 5858 E-mail: [email protected]
Clinical Paper Orthognathic Surgery
Prevalence of infection with the use of b-tricalcium phosphate as a bone graft substitute during Le Fort I osteotomy
M. Ragaey1,2, J. E. Van Sickels1 1
Division of Oral and Maxillofacial Surgery, Chandler Medical Center, University of Kentucky, Lexington, KY, USA; 2ESHA Oral and Cranio-maxillofacial Surgery Center, Agouza, Cairo, Egypt
M. Ragaey, J.E. Van Sickels: Prevalence of infection with the use of b-tricalcium phosphate as a bone graft substitute during Le Fort I osteotomy. Int. J. Oral Maxillofac. Surg. 2017; 46: 62–66. # 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Abstract. While grafting with bone substitutes has been shown to provide greater stability in maxillary advancements, infection remains a concern with any material that is placed in close proximity to the maxillary sinus. The purpose of this study was to evaluate the prevalence of infection in maxillary advancements in which a bone graft substitute (b-tricalcium phosphate; b-TCP) was placed at the time of surgery. This was a retrospective study of all maxillary osteotomies. Patients were divided into two groups: group 1 included maxillary osteotomies in which b-TCP was not used; group 2 included any maxillary osteotomy where b-TCP was used. The prevalence of infection, slow healing, and need for second surgery due to infection or non union was noted. Fisher’s exact test was used to compare differences between the groups. Records were adequate for 438 patients: group 1 included 297 patients, while group 2 included 141. No infections were noted in either group. In group 2, there was one patient who had delayed union/non-union requiring a second procedure. Statically, there was no significant difference between the two groups (P = 0.3219). Based on the data obtained in this study, the use of b-TCP does not increase the incidence of infection or complications when used in Le Fort I maxillary osteotomy.
Introduction
Interpositional bone grafts have been used with maxillary osteotomies for many years. Bone grafts and/or their substitutes can act as mechanical stops reducing relapse, provide a scaffold for bone to grow 0901-5027/01062 + 05
over, and prevent soft tissue herniation or growth into osteotomy sites.1–4 Several authors consider that maxillary advancement of more than 4 mm is problematic in terms of relapse.5,6 Waite et al. compared the stability of large advancements with and without genial bone grafts. They noted
Key words: orthognathic surgery; maxillary advancement; Le Fort I; b-tricalcium phosphate; b-TCP; infection.. Accepted for publication 6 October 2016 Available online 6 November 2016
that the patients who received grafts showed greater stability than those who were not grafted.5 While autologous bone grafting still plays a significant role in clinical practice, many substitutes have been developed to decrease the morbidity associated with
# 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Infection with the use of b-TCP for grafting donor sites.1,7–11 Allografts are a biological alternative to autologous grafts, but they carry a small and real risk of transmission of disease.7,12–14 In contrast, btricalcium phosphate (b-TCP), a synthetic calcium phosphate ceramic, also allows bony regeneration and substitution of bone, but without the risk of disease transmission.13,15,16 It is a biocompatible and absorbable material. The mechanism of bone formation following it use is osteoconduction.8,9 The use of b-TCP as an alternative to traditional bone grafting avoids donor site morbidity and saves time in the operating room. While b-TCP has been shown to be safe, infection remains a concern with any alloplastic material that is placed in close proximity to the maxillary sinus.4 Cottrell and Wolford assessed 245 consecutive patients who had coralline hydroxyapatite placed during orthognathic surgery.4 Of 207 implants that were placed along the lateral sinus wall, 198 remained long term. For the last 6 years, b-TCP (ChronOS; Depuy Synthes, West Chester, PA, USA) has been used routinely to graft maxillary osteotomy sites at the present authors’ institution. In contrast to coralline hydroxyapatite, it is easier to contour and is resorbed in 6–18 months.17,18 The purpose of this retrospective study was to determine the prevalence of infection or delayed healing following the use of bTCP in maxillary osteotomies. Materials and methods
All maxillary orthognathic surgeries done in the department of oral and maxillofacial surgery of the study institution between January 2009 and June 2015 were reviewed. The records were inspected for infection, slow healing, and the need for a second operation. Two groups of patients were selected: group 1 comprised patients for whom b-TCP was not used during the osteotomy (control group), and group 2 included patients in whom b-TCP was used during the osteotomy. Group 2 included maxillary advancements of 4 mm in which b-TCP was wedged between the advanced maxilla and the residual skeletal base, as well as segmented maxillary osteotomies in which b-TCP was wedged between the segments. In both cases, the b-TCP was in close proximity to the maxillary sinus. The patients in group 2 were sub-divided into two groups: one-piece and multiple-piece maxillary osteotomies. The one-piece maxillary osteotomies were further divided into three subgroups according to the degree of advancement:
63
Table 1. Distribution of patients in group 2 (b-TCP used following osteotomy). One-piece maxillary osteotomy* Minor (<5 mm) Medium (5–8 mm) Major (>8 mm) Multiple-piece maxillary osteotomy
Number of cases
Percentage
0 28 43 70
0% 19.9% 30.5% 49.6%
b-TCP, b-tricalcium phosphate. * Patients in the one-piece maxillary osteotomy group were further divided into three subgroups according to the degree of advancement.
minor advancement (<5 mm), medium (5– 8 mm), and major advancement (>8 mm). The segmental osteotomies consisted of two- and three-piece maxillary osteotomies in which b-TCP was used to fill the interdental gaps (Table 1) . For group 1, the inclusion criteria were Le Fort I osteotomy in one or more pieces where b-TCP was not used; complete records; follow-up of 6 months. Exclusion criteria were incomplete follow-up data; use of any grafting material; syndromic patients; patients with cleft lip and palate; previous surgery; a history of trauma. For group 2, the inclusion criteria were one-piece Le Fort I osteotomy with 4 mm advancement, or segmental Le Fort I osteotomy; use of b-TCP in the osteotomy gap; follow-up of 6 months. Exclusion criteria were incomplete follow-up data; use of other grafting materials; syndromic patients; patients with cleft lip and palate; previous surgery; a history of trauma. Fisher’s exact test was used to compare differences between the groups, with significance set at a P 0.05.
b-Tricalcium phosphate bone graft substitute
ChronOS bone graft substitute (Depuy Synthes) is a synthetic b-TCP bone void filler; it is radiopaque, resorbable, and osteoconductive. The material contains calcium and phosphorus and it is resorbed and replaced by bone in 6–18 months.18 It has a similar radiopacity to bone; thus bTCP is frequently difficult to identify in two-dimensional images. Fig. 1 shows a cone beam computed tomography (CBCT) scan obtained immediately postoperative for a Le Fort I advancement case in which b-TCP was used. Fig. 2 shows a CBCT scan obtained at 6 months after surgery; the b-TCP has been resorbed and replaced by bone.
Technique
All Le Fort I osteotomies were performed in a similar fashion.6 In the control group, the maxilla was moved in a variety of directions, but b-TCP was not used as an adjunctive material. In group 2, after the maxilla had been advanced to the
Fig. 1. CBCT obtained immediately postoperative showing the interpositional b-TCP on the lateral and anterior walls of the maxillary osteotomy.
64
Ragaey and Van Sickels Results
Fig. 2. CBCT obtained at 6 months postoperative for a patient who underwent Le Fort I advancement with the use of b-TCP as a bone substitute in the osteotomy. The b-TCP has been completely resorbed and complete bone healing has occurred.
Fig. 3. b-TCP wedges can easily be carved to fit the osteotomy gaps using a No. 15 Bard Parker blade.
desired position, bone plates were used to fix the segments. b-TCP was contoured with a number 15 Bard Parker blade (Fig. 3) and wedged into any gaps 4 mm in size, ensuring contact with the bony segments (Fig. 4). The material is brittle, but it can easily be carved with a number 15 scalpel blade. In segmental Le Fort I osteotomies, the material was
wedged into the interdental gaps after the fabricated splint was ligated to the segments prior to the maxilla being fixed. The segments were gently pried apart with a periosteal elevator to allow the material to be held firmly once the periosteal elevator was removed. This study was approved by the necessary institutional review board.
The records of 457 patients who had undergone a Le Fort I maxillary osteotomy were reviewed. Four hundred and thirtyeight patients had complete records (at least 6 months of follow-up). These patients were divided into two groups: group 1 (control) in which no graft was used (n = 297), and group 2 in which bTCP was used (n = 141) (Table 1). All had undergone a Le Fort I osteotomy (onepiece or multiple segment) with or without b-TCP bone substitute. There were no infections in either group (Table 2). Of the 141 patients in group 2, one patient had delayed union/non union. There was no statistically significant difference between the two groups (P = 0.3219). The patient who required second surgery had undergone a large advancement (8 mm) and admitted to smoking postoperatively. A few weeks after surgery it was noted that the maxilla was mobile. The patient was followed for 5 months, at which point it was noted that the maxilla was firm but had healed in a malocclusion (Fig. 5). In terms of the advancement, none of the study patients in group 2 had a minor advancement (<5 mm), 19.9% had a medium advancement (5–8 mm), and 30.5% had a major advancement (>8 mm). Multiple-piece osteotomies (two- and threepiece maxillary osteotomies, with b-TCP just filling the interdental gaps) accounted for the largest group at 49.6% (Table 1). Details of the follow-up periods and complications are presented in Table 2.
Discussion
Infection was chosen as an outcome measure in this study, as this is usually well documented in the patient records and can have devastating results following elective osteotomy. There was no record of an episode of infection in either study group.
Table 2. Follow-up and complications in the two study groups.*.
Follow-up period Complications Infection Need for a second surgery
Fig. 4. b-TCP placed in the osteotomy gap near the piriform aperture of a large maxillary advancement.
Group 1 (n = 297)
Group 2 (n = 141)
6 months to 6 years 0% 0% 0%
6 months to 6 years 0.7% 0% 0.7%
* Group 1 comprised patients for whom bTCP was not used during the osteotomy (control group); group 2 included patients in whom b-TCP was used during the osteotomy.
Infection with the use of b-TCP for grafting
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Fig. 5. (a) Large maxillary advancement with smaller setback, which ultimately ended in a non union. (b) Five months later, the patient showed non union with a 4-mm relapse of the maxilla.
One of the problems associated with large advancement of the maxilla (4 mm) is relapse.5,6 Grafting osteotomy sites has been shown to prevent or minimize relapse in multiple studies.19– 21 While bone grafts have been used for years, the morbidity at the donor site and the additional time taken to obtain the graft are well known.1–3,18 The rationale for using a bone substitute is to decrease the time in the operating room and to decrease the patient’s discomfort. Lye et al. used demineralized bone to fill the voids following maxillary advancements of 4 mm in 61 patients.1 They noted a 3.3% incidence of maxillary sinusitis in this group and 8% incidence in patients who had other graft materials. Sinusitis was not recorded in the patient groups in the present study. All of the patients were prescribed antibiotics and decongestants after surgery. While sinusitis may have occurred in some of the subjects, it was not recorded in the charts. Cottrell and Wolford used coralline hydroxyapatite in a manner very similar to how b-TCP was used in the present study.4 They did not lose any coralline hydroxyapatite implants that were placed interdentally, but lost seven that were placed between palatine sites and nine along the lateral sinus wall. Infection was not seen in either of the two groups in the present study, nor was there any loss of the implants that were placed. b-TCP has been used in sinus lifts by itself and in combination with other material.18,22 In this application there is formation of bone, and infection does not appear to be a problem.
In this study there was one case of delayed union/non union in a large advancement (Fig. 5). The patient was a 19year-old male who admitted to smoking. Cigarette smoking is known to impede bone healing.23 It is also known to be a risk factor for postoperative complications.23–25 Whether the patient’s smoking habit was the reason for the difficulty with healing is unknown. Interestingly, Cottrell and Wolford lost nine implants that were placed in the lateral maxillary wall in three patients, and two of the three were smokers.4 No other complications were documented in either of the groups of patients in the present study. A weakness of this study is that it was retrospective in design. A strength is that it represents a large number of patients treated over a considerable period of time, all treated by the same surgeon. The b-TCP material comes in blocks or wedges, and although brittle, it is relatively easy to carve (Fig. 3) and to adapt to osteotomy sites. The time required to place it is about 10 min. This is considerably less than the time that it takes to obtain a graft from another site and fashion it to fit an osteotomy gap. Currently, there appears to be no study reported in the literature that has examined the prevalence of infection following the use of b-TCP in maxillary surgery. The results of this study indicate that the use of b-TCP as a bone graft substitute is safe, with a minimal prevalence of infection and dehiscence compared to allografts.1,12,14,26 There was no evidence of rejection and it appears that b-TCP is completely resorbed and replaced by bone over a period of 18 months. Thus b-TCP
can safely be used as a bone graft substitute in Le Fort I osteotomies to fill the osseous voids when the maxilla is advanced or segmented. Funding
None. Competing interests
None. Ethical approval
This study was approved by the Institutional Review Board of the University of Kentucky (approval number 16-0054X2B). Patient consent
No clinical photographs are included. This was a retrospective study and qualified for a waiver of informed consent as per the Institutional Review Board. Acknowledgements. The authors would like to express their gratitude to Christina Lewis, clinic manager of the Oral and Maxillofacial Surgery Division, College of Dentistry, University of Kentucky, Lexington, Kentucky, for her help with the medical records.
References 1. Lye KW, Deatherage JR, Waite PD. The use of demineralized bone matrix for grafting during Le Fort I and chin osteotomies:
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Address: Marwa Ragaey Division of Oral and Maxillofacial Surgery Chandler Medical Center University of Kentucky 800 Rose Street Lexington KY 40536-0297 USA Tel: +1 347 331 1119; Fax: +1 859 323 5858 E-mail: [email protected]