Abstract
The use of costochondral graft is controversial for pediatric temporomandibular joint reconstruction due to its unpredictable growth. The height of the cartilage is directly responsible for the growth capacity of costochondral graft. Even after keeping the cartilage in costochondral graft to a recommended height, overgrowth has been reported. Traditionally during costochondral graft fixation, chin deviation is corrected intraoperatively. The investigators hypothesized that this intraoperative manipulation of mandible to correct chin deviation and maintaining the chin in new position causes excessive stress and strain in the muscular functional matrix. The authors believe that this may be the reason for excessive growth trigger on the grafted side. This study intends to prove the hypothesis of no-intraoperative correction of chin deviation can prevent overgrowth of the costochondral graft. We implied this technique in pediatric temporomandibular joint ankylosis patients managed with osteoarthrectomy and reconstructed with costochondral graft. Patients with at least a follow-up of 30-months were included in the study. The study sample consisted of 20 patients. All the patients had adequate growth with improvement in facial asymmetry. The results of the present study supports our hypothesis of no-intraoperative correction of chin deviation as a technique to prevent overgrowth of costochondral graft. We recommend this technique to allow catch-up of growth rather than acceleration of growth. This change in technique needs more research, randomized controlled trial for reliability and long-term results.
Keywords: Costochondral graft, Overgrowth, Temporomandibular joint, Temporomandibular Joint ankylosis
Graphical abstract
1. Introduction
Ramus-condyle unit (RCU) reconstruction by autogenous costochondral graft (CCG) is used primarily for paediatric temporomandibular joint (TMJ) ankylosis. In pediatric patients, along with restoration of maximal incisal opening (MIO), preventing re-ankylosis and subsequent growth of mandible are the main goals. Even though CCG is considered as gold standard in management of pediatric temporomandibular joint ankylosis (TMJA), some authors oppose its use because of its unpredictable growth.1 Balaji and Balaji in their study of 14 patients have reported, normal growth in only 2 (14%) patients, 5 (35%), patients had moderate growth, overgrowth was seen in 4 (28%) and no growth was seen in 3 (21%) patients at a mean follow-up of 3-years.1 Both overgrowth and undergrowth can result in facial asymmetry. The overgrowth of the graft is more problematic than undergrowth.2 Guyuron and Lasa in their study, reported overgrowth in 50% of patients, 37.5% had no growth with suboptimal growth only in 12.5% patients at mean follow-up of 80.4 months.2 To prevent overgrowth of graft, length of the cartilage should be kept 2–4 mm.3 Peltomaki et al. found that the height of cartilage is directly responsible for the growth capacity of CCG.4 Kaban et al. however suggest 1–2 mm cartilage height.5 The growth ensues as the functional matrix around mandible is activated due to movement restoration after osteoarthrectomy. This along with the cartilage, which acts as secondary growth center results in growth. It is however still not clear if the cartilage as primary growth center or functional matrix along with cartilage is responsible for growth. Transplantation of growth center along with function leads to catch-up of growth ,which may not occur if no growth center in transplanted like in gap arthroplasty.
2. Hypothesis
Traditionally during CCG fixation, chin deviation is corrected intraoperatively. The intraoperative manipulation of mandible to correct chin deviation and maintaining the chin in new position causes excessive stress and strain in the muscular functional matrix. The excessive stress of muscle matrix is interpreted as requirement of more growth on the grafted side. The authors believe that this may be the reason for excessive growth trigger on the grafted side. The primary growth of the lateral pterygoid, medial pterygoid, masseter, and temporalis muscle causes growth change in the mandible. The authors have reconstructed 20 TMJ in ankylosis (Sawhney's type 3 and 4) patients with age range of 9–12years. No intraoperative correction of the chin deviation was done to compensate for the already set-in facial deformity. The CGG with 2–4 mm cartilage height was fixed passively and packed with fat. A standard surgical technique for arthroplasty and CCG was performed in all patients. Standard preauricular approach was used for osteoarthrectomy and submandibular/retromandibular approach was used for CCG fixation. Layer-wise dissection was done to expose ankylotic mass and lateral ramus of the mandible. Branches of the facial nerve were carefully protected. Pterygomassestric sling was divided, periosteum was incised at lower and posterior border to expose ramus. Inferior osteotomy cut was kept below the ankylotic mass. An osteoarthrectomy creating a gap of approximately 15 mm was obtained. Primary CCG reconstruction was done as per Kaban, Bouchard and Troulis protocol.6 No attempt was made to correct pre-existing mandibular deformity intraoperatively. This reduces the stress on the functional matrix and a catch-up growth takes place rather than stresses on muscle matrix sending signals for excessive want of growth. Passive adaptation of CCG allows for an undisturbed healing without undue stress or strain. Fixation was done with two bicortical screw and washer. The use of bicortical titanium screws with washer provide sufficient stability required for healing. Patients were not kept on maxillomandibular fixation (MMF) postoperatively. Fixation with washer plate and bicortical screws provide rigid fixation and help avoid MMF in immediate postoperative period,6 when the chances of heterotopic bone formation are maximum. Thus, immobilization by MMF immediate postoperatively in CCG reconstruction raises a question. Superior most point of CCG was marked and was taken as condylion. Mandibular length was measured from condylion to gnathion on posterior-anterior cephalogram. Mandibular length was compared from immediately postoperative to follow-up. Mean mandibular length immediate postoperative was 56.88 ± 12.92 mm and at follow-up, mean mandibular length was 71.45 ± 15.02 mm. The difference was statistically significant (p < 0.001). Length from condylion to gonion was also measured on grafted side immediate postoperatively and compared with follow-up value. The difference was statistically insignificant (p = 0.08). Improvement in midline deviation was statistically insignificant between immediate postoperative to follow-up (p = 0.10). The difference in chin deviation was statistically significant from immediately postoperative period to follow-up (p = 0.01). Facial asymmetry correction was seen in all the patients, and all patients had adequate MIO. The facial asymmetry improved from median of 5 mm immediately postoperative to 3 mm at follow-up. The difference was statistically significant (p-value = 0.004). At follow-up of 30-months, there was no incidence of overgrowth in any of the patient included in the study (Fig. 1, Fig. 2).
Fig. 1.
Preoperative 3D CT showing reduced growth on side of ankylosis (Right) and chin deviation.
Fig. 2.
36-month follow-up 3D CT showing chin and facial symmetry correction due to growth subsequent to CCG grafting.
3. Discussion
Systematic review on CCG growth has documented that at a minimum follow-up of 5 years, 54 grafts, in 96 patients, had optimum growth, 1 graft showed undergrowth, 7 showed overgrowth, 1 had lateral overgrowth and 1 had no growth.7 None of the patients, in the present study showed overgrowth or no-growth. We attribute low overgrowth in our series to not correcting the deviated mandible intraoperatively and fixing CCG passively without causing any added stress to surrounding functional matrix. It is common to make intraoperative changes in mandibular position to obtain most acceptable occlusion and deviation correction.8 We believe that this manipulation for correcting the deviated mandible puts excessive strain and stress to the surrounding musculature which is interpreted for increased requirement of growth. The CCG fixed in this position also has constant backward pressure from the mandible to return to original position. This causes continuous strain on CCG and may result in fracture of cartilage or excessive bone formation due to micromotion and increased stresses resulting in re-ankylosis. Rib fracture due to excessive strain after advancement of mandible has also been reported.9 Our technique helps the CCG to catch-up with the growth and not accelerate the growth. MMF was done in pre-existing occlusion intraoperatively and graft was fixed passively to prevent excessive traction on graft and musculature. In our opinion, no-intraoperative correction of chin deviation may be the reason for less incidence of overgrowth in our population.
CCG is considered as primary growth center and its growth potential is under the control of both, extrinsic (effect of functional matrix) as well as intrinsic factor (effects of hormones).10 Along with intraoperative correction of chin deviation, other causes of overgrowth are height of cartilage, lack of adaptation of graft to growth velocity of the new tissue environment and instability of graft during function, load-bearing condition of a new environment, re-attachment of lateral pterygoid muscle on graft and traction of fibrous tissue and role of growth hormones and factors.
The authors recommend this technique to allow catch-up of growth rather than acceleration of growth. However, long-term follow-up is required to comment on growth potential of CCG. This change in technique needs more research, randomized controlled trial for reliability and long-term results. We are planning to conduct a randomized controlled trial on outcome of costochondral graft with or without correction of chin deviation to support the same hypothesis.
Source of support
None.
Declaration of competing interest
None.
References
- 1.Balaji S., Balaji P. Overgrowth of costochondral graft in temporomandibular joint ankylosis reconstruction: a retrospective study. Indian J Dent Res. 2017;28:169. doi: 10.4103/ijdr.IJDR_141_17. [DOI] [PubMed] [Google Scholar]
- 2.Guyuron B., Lasa C.I., Jr. Unpredictable growth pattern of costochondral graft. Plast Reconstr Surg. 1992;90:880–886. [PubMed] [Google Scholar]
- 3.Lakshmanan S., Roychoudhury A., Bhutia O., Yadav R., Bhatt K., Pandey R.M. Can costochondral grafts fulfil ramus-condyle unit reconstruction goals in children with temporomandibular joint ankylosis? [published online ahead of print, 2020 Aug 15] Br J Oral Maxillofac Surg. 2020;S0266–4356(20):30410–30411. doi: 10.1016/j.bjoms.2020.08.021. [DOI] [PubMed] [Google Scholar]
- 4.Peltomäki T., Häkkinen L. Growth of the ribs at the costochondral junction in the rat. J Anat. 1992;181:259–264. [PMC free article] [PubMed] [Google Scholar]
- 5.Kaban L.B., Bouchard C, Troulis M.J. A protocol for Management of TMJ Ankylosis in children. J Oral Maxillofac Surg. 2009;67(9):1966–1978. doi: 10.1016/j.joms.2009.03.071. [DOI] [PubMed] [Google Scholar]
- 6.Monje F., Martin-Granizo R. The “green-stick” fracture technique for adaptation and fixation of costochondral grafts. J Oral Maxillofac Surg. 1998;56(1):103–105. doi: 10.1016/s0278-2391(98)90927-2. [DOI] [PubMed] [Google Scholar]
- 7.Kumar P., Rattan V., Rai S. Do costochondral grafts have any growth potential in temporomandibular joint surgery? A systematic review. J Oral Biol Craniofac Res. 2015;5:198–202. doi: 10.1016/j.jobcr.2015.06.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.MacIntosh R.B. The use of autogenous tissues for temporomandibular joint reconstruction. J Oral Maxillofac Surg. 2000;58(1):63–69. doi: 10.1016/s0278-2391(00)80019-1. [DOI] [PubMed] [Google Scholar]
- 9.Mao Y., Chen X., Yu S. Biomechanical analysis of costochondral graft fracture in temporomandibular joint replacement. Sci Rep. 2020;10(1):17754. doi: 10.1038/s41598-020-74548-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Moss M.L. The differential roles of periosteal and capsular functional matrices in oro-facial growth. Rep Congr Eur Orthod Soc. 1969:193–205. [PubMed] [Google Scholar]