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condyle unit: Long-term follow-up
Int, J. Oral Maxillofac. Surg. 1994," 23." 321-328 Printed in Denmark. All rights reserved
Copyright © M u n k s g a a r d 1994 InternationalJournal of
Oral& Max ofacial SurEery ISSN 0901-5027
Aesthetic and reconstructivesurgery
Costochondral graft construction/reconstruction of the ramus/condyle unit: long-term follow-up
David H. Perrott 1, H i r o n o b u U m e d a 1, L e o n a r d B. Kaban 2 1University of California San Francisco,
Department of Oral and Maxillofacial Surgery, San Francisco, CA; 2Department of Oral and Maxillofacial Surgery, Harvard School of Dental Medicine and Department of Oral and Maxillofaciat Surgery, Massachusetts General Hospital, Boston, MA, USA
D. H. Perrott, H. Umeda, L. B. Kaban: Costochondral graft construction~reconstruction of the ramus/condyle unit: long-term follow-up. Int. J. Oral Maxillofac. Surg. 1994," 23:321 328. © Munksgaard, 1994 Abstract. This is a retrospective study of 26 patients (seven growing and 19 nongrowing) who received costochondral grafts (n=33) for construction or reconstruction of the ramus/condyle unit (RCU). Facial appearance, jaw motion, occlusion, contour, and linear growth changes were documented preoperatively, immediately postoperatively, and long-term (>1 year). Average follow-up was 48.6 months for growing and 46.4 months for nongrowing patients. Facial asymmetry and malocclusion were successfully corrected in all patients except for those with hemifacial microsomia, where partial correction was most common. For the growing patients, mean change in R C U length (n=8) during the observation period was +3.1 mm on the constructed/reconstructed side and +3.2 mm on the unoperated side. For nongrowing patients, mean change in the R C U length (n=25) was -5.7 mm for the reconstructed side. Three patients developed lateral contour overgrowth of the articulating surface; no patients developed clinically significant linear overgrowth with malocclusion. The results of this study indicate that a costochondral graft may be used successfully to construct/reconstruct the RCU and that linear overgrowth of the graft does not appear to be a clinical problem with the method described in this paper.
Construction or reconstruction of the mandibular ramus/condyle unit (RCU) for acquired or congenital defects remains a difficult problem in maxillofacial surgery. A successful result requires restoration of proper mandibular length and form, normal motion, occlusal stability, and, in children, subsequent symmetric growth of the mandible. Reconstructive methods using autogenous tissues such as those of metatarsal head 2, fibula26, and sternoclavicular joint 24, and costochondral rib grafts 1'4'13'14'21 have been reported. In addition, alloplastic materials have
been advocated as an alternative to autogenous grafts II. The costochondral graft is the most common autogenous reconstruction method reported in the literature. Investigations by SARNAT & ENGEL23, POSWILLO20, MOSS • SALENTIJN15, WARE & TAYLOR26, PETROVIC et al. 18, FIGUEROA et al. 4, and ELLIS & CARLSON3 have established the biologic basis for its use. There is, however, controversy regarding the growth potential of the grafted RCU, especially in children with post-traumatic and congenital defects 10,14,27. Authors of clinical and
Key words: costochondral graft; temporomandibularjoint reconstruction; temporomandibular joint, condyle replacement. Accepted for publication 12 July 1994
radiographic studies have reported no growth in some cases and excessive growth in others 5,1°,14,16,27. This study assesses the long-term results of costochondral grafting for construction or reconstruction of the R C U in nongrowing and growing patients. Special attention was directed toward obtaining objective documentation of linear changes in the constructed/reconstructed RCU. Material and m e t h o d s
The study population consisted of 26 patients (33 costochondral grafts) who under-
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went construction/reconstruction of the R C U at the University of California San Francisco (UCSF) in 1986-91. Indications for construction/reconstruction included ankylosis, condylar resorption, degenerative joint disease (DJD), or congenital absence of a condyle (Tables 1 and 2). All patients had at least a 1-year follow-up. Facial appearance (symmetry, asymmetry), maximal incisal opening (MIO), occlusion, and contour or linear changes of the operated (abnormal) and unoperated (normal) R C U s were documented by history, physical examination, and measurements on serial panoramic radiographs.
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All patients underwent the same operative procedure. First, the fifth and sixth ribs were exposed through an inframammary incision. One or both o f the ribs were harvested by a subperiosteal method 7. The graft was composed of a 5-6-cm bony and a l-l.5-cm cartilaginous component. The wound was closed in layers. The temporomandibular joint (TMJ) was approached through a curvilinear preauricular incision which extended 3 cm into the temporal region for exposure of the temporalis fascia. The dissection proceeded in this plane to the zygomatic arch. The periosteum over the arch was incised horizontally, and the joint was entered through a Tshaped incision over the lateral capsule. A hemicoronal or coronal flap was utilized to expose the TMJ in patients who had had multiple previous operations, who required bilateral TMJ reconstruction, or who required simultaneous coronoidectomy (e.g., ankylosis cases). In patients with ankylosis, DJD, tumor, or idiopathic condylar resorption, an ostectomy was done from the sigmoid notch to the posterior border o f the ascending ramus ~. Ipsilateral coronoidectomy was done in patients with ankylosis. A submandibular incision was then made to expose the angle and ramus of the mandible for fixation of the graft. In hemifacial microsomia (HFM) patients, an osteotomy o f the opposite mandibular ramus was done to allow for jaw advancement, elongation, and rotation. If an intact disk was identified during joint exploration, it was maintained to line the glenoid fossa ( n - 1 0 joints). In other cases, the TMJ was lined with a finger-shaped temporalis muscle/fascia flap, as described by POOR.EL & KABAN~9 (n=22) (Fig. 1). If temporalis fascia had been used in a previous operation, or if it was congenitally absent, perichondrium (harvested at the same time as the costochondral graft) was used as a free graft to line the glenoid fossa (n = 1). The occlusion was established by placing the patient into maxillomandibular fixation in a prefabricated occlusal splint. A 2-3-mm posterior open bite was created on the operated side to compensate for remodeling of the costochondral graft.
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P e r r o t t et al. were modified by the correction factor if the molar measurement was not equal to that found on the To radiograph.
Results Clinical analysis (Tables 1 and 2)
Preoperative evaluation (To)
Fig. 1. a) Photograph and b) corresponding diagram of costochondral graft (B) secured with screws and temporalis muscle flap (A) lining glenoid fossa.
Construction/reconstruction of the RCU was achieved with the costochondral graft. The cartilage of the graft was contoured to be 2-4 mm thick and round (Fig. 2). Rib graft length was determined by the ramus height discrepancy and the amount of facial asymmetry to be corrected. The lateral ramus and rib were trimmed and contoured to obtain a good bony interface. The superior (cartilaginous) surface of the graft was then placed against the joint lining, and the graft was rigidly secured to the mandible with two or three 2.0-mm or 2.7-mm pretapped bone screws (Figs. 1 and 3). A drain was placed, the incisions closed, and a pressure dressing applied. M M F was maintained for 3-10 days, depending on the thickness and rigidity of the costochondral graft. After release of M M F (mean-10.1--3.4 days), the patients were started on a soft diet and jaw-opening exercises. During the next 3 4 weeks, the diet was advanced to a solid consistency. The physiotherapy program consisted of heat, massage, ultrasonography, gum chewing, manual stretching, and the Bell Dynamic Jaw Exerciser (Walter Lorenz Surgical Instruments, Inc, Jacksonville, FL, USA) or Therabite (Walter Lorenz Surgical Instruments). Six weeks postoperatively (in ankylosis cases), if the patient was not able to achieve the documented intraoperative MIO and showed no signs of improvement, the jaws were stretched under general anesthesia. Patients were followed on a monthly basis for at least 1 year.
Clinical analysis Clinical analysis was completed preoperatively (To), 1 month postoperatively (T1), and long-term (T2). Facial symmetry was docu-
mented by determining the relationship of the chin point to the midsagittal plane and the linear distance from the inferior mandibular border to the zygomatic arch. Occlusion was documented and classified as stable or unstable. Stable occlusion was defined as good interdigitation of all the teeth without signs of prematurities or open bite. MIO was measured with a rigid triangular measuring device placed between the maxillary and mandibular central incisors in the midline. Presence or absence of pain was noted and compared with the preoperative condition.
Radiographic analysis Panoramic radiographs were taken preoperatively (To), immediately postoperatively (T1), and at yearly intervals (T3). Outlines of the constructed/reconstructed and unoperated (normal) RCUs were traced over the radiograph, and direct measurements were made by two, independent investigators. The length of the constructed/reconstructed RCU or unoperated RCU was the perpendicular distance (mm) from a line tangent to the articulating surface to the point of intersection of lines tangent to the posterior and inferior borders of the mandible 7 (Fig. 3a). To compensate for angulation and other procedural differences associated with the use of panoramic radiographs, we used the ratio of unoperated to operated RCU length in unilateral cases and mathematically corrected for magnification in both unilateral and bilateral cases. The mesiodistal measurement of the same right and left molar on the To radiograph was used as a constant reference (Fig. 3a). Linear measurements of the RCUs obtained on subsequent radiographs
T h e 26 patients were analyzed a n d divided into two groups: growing a n d nongrowing. T h e r e were three male a n d four female growing p a t i e n t s (-<16 years of age) with eight involved T M J s (six unilateral, one bilateral) (Table 1). M e a n age at the time o f o p e r a t i o n was 10.59 years (range ~ 1 6 ) . I n d i c a t i o n s for the o p e r a t i o n included post-traum a t i c ankylosis ( n = 4 ) a n d H F M (n = 3). Preoperatively, 6/7 p a t i e n t s h a d a n asymmetric mandible, 0/7 h a d pain, a n d 5/7 h a d unstable occlusion. In the four patients with restricted j a w motion, the m e a n M I O was 14.2 m m (range 1 0 ~ 0 ) . There were four male a n d 15 female n o n g r o w i n g patients ( > 1 6 years old) with 25 involved T M J s (13 unilateral, six bilateral) (Table 2). M e a n age at the time of o p e r a t i o n was 35.64 years (range 20-58.20). I n d i c a t i o n s for the o p e r a t i o n included b o n y or fibrous ankylosis (n=10), c o n d y l a r r e s o r p t i o n (n=4), t r a u m a ( n = l ) , a u t o i m m u n e arthritis ( n = l ) , D J D ( n = 2 ) , a n d t u m o r (n = 1). Preoperatively, 9/19 p a t i e n t s h a d a n asymmetric mandible, 11/19 h a d pain, a n d 9/19 h a d a n u n s t a b l e occlusion. In the 10 patients with restricted jaw m o t i o n , the m e a n M I O was 14.7 m m (range 2-25). In growing patients, the glenoid fossac were lined with native disk (n=3), temporalis muscle/fascia flap (n=3), a n d p e r i c h o n d r i u m ( n = 1). In the n o n growing group, the glenoid fossae were lined with native disk ( n = 8 ) a n d temporalis muscle/fascia flap (n = 17).
Fig. 2. Harvested costochondral graft showing 3-mm cartilaginous cap.
Costochondral grafts in RCU reconstruction
Immediate postoperative follow-up One month postoperatively (T1), the four growing patients who had ankylosis release and reconstruction with costochondral grafts had achieved mandibular symmetry. Three H F M patients had improvement of skeletal symmetry as a result of the constructed RCU. No patients had pain. All patients maintained the surgically created open bite on the operated side. One month postoperatively (T1), all 10 nongrowing patients who underwent correction of asymmetry remained stable. Nine nongrowing patients who were symmetric before surgery remained so. Pain was present but improved in 10/19 patients and absent in the other 9/19 patients. All patients maintained the surgically created open bite on the operated side.
Long-term follow-up In the growing patients, the average long-term follow-up (T2) was 48.6 months (range 24-72). Clinically, there were no signs of linear overgrowth of the constructed/reconstructed RCUs. All three H F M patients remained asymmetric but were significantly improved. Two (one H F M ; one nonH F M ) growing patients developed lateral contour overgrowth of the constructed/reconstructed RCUs (Figs. 4a and b). Lateral contour overgrowth was
defined as an abnormal increase in mass in the region of the costochondral junction. It may be associated with decreased motion, but contour overgrowth is not usually associated with changes in occlusion. The long-term MIO was 36.0 mm (range 27-51) in the four patients with preoperative ankylosis. This long-term change in the MIO was statistically significant (P<0.05), as compared with preoperative measurements. In the nongrowing patients, the average long-term follow-up (T2) was 46.4 months (range 14-40). At the end of the follow-up period, four patients had a clinically visible mandibular asymmetry. Two asymmetries were the result of contralateral (unoperated) condylar resorption, and two were the result of remodeling (a decrease in length) of the reconstructed RCU. No patients showed clinical signs of linear overgrowth. One patient did develop lateral contour overgrowth in the region of the costochondral junction. Of the 12 patients with preoperative pain, six had resolution of the pain and six had improved/manageable pain. Three patients developed unstable occlusion as a result of R C U shortening (n=2) and contralateral R C U resorption (n=l). In the patients with restricted preoperative jaw motion, the mean long-term MIO was 33.9 mm (range 25-49). This change in MIO was statistically significant (P<0.05), as compared with the pre-
325
operative measurements. In patients with normal motion preoperatively, there was no postoperative hypomobility. Radiographic analysis (Tables 1 and 2)
In growing patients (Table 1), the mean change of the constructed/reconstructed R C U (T 2 T1) was -2.8_+4.2 mm (range ~9] [+3]), and for the unoperated R C U it was +3.2 mm (range ~1] [+7]). Three constructed/reconstructed RCUs in two patients (Table 1) increased in length. In patient no. 5 (bilateral), both sides increased equally, as desired. In patient no. 7, the constructed R C U increased in length equal in amount to growth of the unoperated side. However, most of the constructed/reconstructed RCUs (n=5 in five patients) decreased in length. In nongrowing patients (Table 2), the mean change in the reconstructed R C U length (T2 Yl) was 5.7 mm (range [16.0]-[+4.0]) (Table 2). On the unoperated side, there was an insignificant change in length of 0.1 mm. In 22/25 reconstructed RCUs, there was an overall decrease in the reconstructed R C U length as a result of settling and remodeling. In one patient (no. 14), there was an increase in the reconstructed R C U length, while the contralateral reconstructed R C U decreased in length, resulting in a symmetric mandible. In one patient (no. 16), the reconstructed
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Perrott et al. Fig. 4. Sixteen-year-old girl 2 years after treatment of TMJ ankylosis with resection, costochondral graft, and temporalis muscle fascia flap. Patient shows lateral contour overgrowth of left reconstructive RCU (arrow). a) Frontal view showing left, lateral overgrowth of RCU (arrow). b) Frontal view showing good MIO and left, lateral overgrowth (arrow). c) Intraoral photo showing stable occlusion with no open bite or midline shift, d) Intraoperative photo after division of temporalis muscle flap (A) and exposure of RCU. Overgrowth of reconstructed RCU (B) has encompassed original costochondral graft. There is no linear overgrowth, e) Intraoperative photo after removal of lateral overgrowth (B) and maintenance of temporalis muscle (A).
RCU increased by an amount equal to that of the contralateral unoperated RCU. In both the growing and nongrowing patients, the mean dimensional change of the reconstructed RCU and native R C U was not statistically significant (P<0.05). In summary, in both growing (5/8) and nongrowing (22/25) constructed/reconstructed RCUs, there was a mean decrease in length during the follow-up period. Discussion
The costochondral graft is a common method to construct/reconstruct the RCU because it provides: 1) autogenous material without the possibility of a foreign-body reaction, 2) a cartilaginous articulating surface, 3) the possibility of permanent bony union and biologic remodeling in response to function, 4) growth potential. Furthermore, there is minimal donor site morbidity. The disadvantages of this method are a requisite additional surgical procedure and potential associated donor site morbidity. In addition, accurate prediction of linear changes of the constructed/reconstructed RCU has not been possible. It is also difficult to measure accurately and document results of RCU construction/reconstruction because of radiographic limitations. Financial costs and lack of standard head position prohibit the use of coronal computer tomograms. Although cephalograms may be helpful in identifying asymmetries, direct linear measurements of the R C U cannot be done. From a practical standpoint, a panoramic radiograph is useful. Limitations associated with the panoramic
Costochondral grafts in R C U reconstruction
radiograph include nonreproducible head position and resultant distortion and magnification error. In this study, we attempted to compensate for these limitations by using the same panoramic x-ray machine for all radiographs and by calculating a constant mathematic measurement of the right and left molar mesiodistal length. In addition to linear measurements, we used serial ratios of unoperated to operated RCU sides (Tables 1 and 2). Since 1920, when GILLIES first described the use of the costochondral graft to reconstruct a RCU, its use and reported results have remained a focus of great discussion 14. The costochondral graft appears to provide adequate strength and bony continuity for the mandible to function, although there have been reports of the cartilage fracturing from the rib I2'27. In this study, no problems with regard to strength were identified. Postoperative function was excellent except in the patients with lateral contour overgrowth who experienced some decrease in mandibular motion. Two patients did develop an unstable occlusion as a result of shortening, settling, and remodeling of the constructed/reconstructed RCU. Many reports have documented the rationale for use of the costochondral graft for construction/reconstruction of the RCU. The costochondral graft is a growth center and it adapts to function. Initially, its morphologic character does not resemble that of native condylar cartilage; however, it remodels over a period of time and eventually becomes similar to native condylar cartilage3,5,18,20,22,26. The growth of the costochondral graft is controlled by intrinsic (growth centers) and/or extrinsic (functional matrix) factors 6,16'1s. Although there was no clinically significant linear overgrowth of the constructed/reconstructed RCU, we did document contour overgrowth of the articulating surface in a small group of growing and n0ngrowing patients. Lateral contour overgrowth was significant as an aesthetic problem. Although these patients did not develop malocclusion, there was a decreased mandibular motion as reported in other papers 5'13. This finding is important in that the contour overgrowth of the articulating surface may produce deviation of the chin Point toward the normal side by a mass effect on the position of the
jaw while not increasing the linear length of the RCU. The development of asymmetries in four nongrowing patients is an important observation because we usually assume that patient asymmetries are secondary to costochondral graft overgrowth. In two patients, the asymmetry was the result of contralateral condylar resorption. Two of the patients developed asymmetries because of graft resorption, not overgrowth. The pathogenesis is not clear and probably falls into the same category of idiopathic condylar resorption that is seen in the setting of orthognathic surgery. All patients in this study achieved good postoperative MIO. There appeared to be no correlation between MIO and changes in size of the constructed/reconstructed RCU. The role of function in long-term dimensional changes of the constructed/reconstructed R C U remains unclear, especially in patients with congenital deformities such as H F M . MULLII~N et al. suggest that the effect of the functional matrix upon growth of the costochondral graft should rather be deemed one of a dysfunctional matrix in H F M patients 16. Little attention has been directed toward the size of the cartilage cap on the graft and its relation to linear changes. Most reports describe a cartilage length ranging from 0.5 to 2.5 cm 9'27. It has been hypothesized that as much cartilage should be preserved to achieve a growth pattern similar to that of the native condyle and prevent ankylosis 12. In contrast, TIDEMAN & DODDRIDGE25 feel that a smaller cartilage cap prevents a fracture at the costochondral junction and may play a role in diminishing the potential for overgrowth of the graft. This hypothesis is supported by PETRO¥IC et al.'s suggestion that the costochondral graft's growth potential may be enhanced by preserving a larger amount of cartilage, which may be responsive to intrinsic as well as local extrinsic factors is. This is further supported by experimental studies by PELTOMA.K117.
In our study, all patients were constructed/reconstructed with a costochondral graft using only 2-4 mm of cartilage. When growth did occur, it was equal to or less than the unoperated R C U and was not clinically significant. The only clinically significant asymmetry occurred as a result of con-
327
tour changes at the articulating surface. These findings indicate that the length of the cartilage may be an important factor in determining linear and contour changes of the constructed/reconstructed RCU. In conclusion, this long-term retrospective study showed that the costochondral graft is an acceptable method to construct/reconstruct the R C U in growing and nongrowing patients. On average, the constructed/reconstructed R C U decreased in length in both groups. There was no clinically significant linear increase in length of the constructed/reconstructed RCU. Therefore, we recommend overcorrection by creating an open bite on the operated side. This is maintained by an occlusal splint and gradually closed by adjusting the splint after 3 months postoperatively. Further studies are needed to address the effects of cause (congenital in comparison with acquired), specific surgical methods, inherent qualities of the costochondral graft, systemic factors, postoperative function and physiotherapy, muscle, periosteum, and size of the cartilage cap on the long-term growth of the constructed/reconstructed RCU. Assessment of growth must be documented by specific radiographs and measurements. Acknowledgment. This research was in part funded by the University of California San Francisco Oral and Maxillofacial Surgery Research Fund.
References
1. BOWERMAN SE. Reconstruction of the temporomandibular joint for acquired and congenital malformation. Br J Oral Maxillofac Surg 1987: 25: 149-60. 2. DINGMANRO, GRAB• WC. Reconstruction of both mandibular condyles with metatarsal bone grafts. Hast Reconstr Surg 1964: 34: 441-51. 3. ELLIS E, CARLSONDS. Histological comparison of the costochondral, sternoclav-
icular, and temporomandibular joint during growth in Macaca mulatta. J Oral Maxillofac Surg 1986: 44: 312-21. 4. FIGUEROAAA, GANS BJ, PRUZANSKYS. Long-term follow-up of a mandibular costochondral graft. Oral Surg 1984: 58: 257-68. 5. GUYURON G, LASA C][ Jr. Unpredictable
growth pattern of costochondral graft. Hast Reconstr Surg 1992: 90: 880-6. 6. [SAKSSON OPG, LINDHAL A, NILSSON A,
ISGAARDJ. Mechanism of the stimulatory effect of growth hormone on longitudi-
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hal bone growth. Endocr Rev 1987: 8: 426-38. 7. KABAN LB, MULLIKEN JB, MURRAY JE. Three dimensional approach to analysis and treatment of hemifacial microsomia. Cleft Palate J 1981: 18:90 9. 8. KABAN LB, PERROTT DH, FISHER K. A protocol for management of temporomandibular ankylosis. J Oral Maxillofac Surg 1990: 48: 1145-51. 9. KABAN LB, PERROTT DH. Discussion. Unpredictable growth pattern of costochondral graft. Plast Reconstr Surg 1992: 90: 887-8. 10. KENNETT S. Temporomandibular joint ankylosis: the rationale for grafting in the young patient. J Oral Surg 1973: 31: 744 8. 11. KENT JN, MISIF~KD J, SHEN RK, HrNDS EC, HONSY CA. Temporomandibular joint condylar prosthesis: a ten-year report. J Oral Maxillofac Surg 1983: 41: 245-54. 12. LINDQVIST C, PIHAKARI A, TASANEN A, HAMPF G. Autogenous costochondral grafts in temporomandibular joint arthroplasty. J Maxillofac Surg 1986: 14: 143-9. 13. LINK JO, HOFFMAN DC, LASKIN DM. Hyperplasia of a costochondral graft in an adult. J Oral Maxillofac Surg 1993: 51: 1392-4. 14. MACINTOSH RB, HENNY FA. A spectrum
of application of autogenous costochondral grafts. J Maxillofac Surg 1977: 5: 257 67. 15. Moss ML, SALENTIJN L. The primary role of functional matrices in facial growth. Am J Orthod 1969: 55: 566-77. 16. MULLIK~N JB, FERRARONF, VENTO AR. A retrospective analysis of growth of the constructed condyle-ramus in children with hemifacial microsomia. Cleft Palate J 1989: 26: 312-17. 17. PELTOMAKIT. Growth of a costochondral graft in the rat temporomandibular joint. J Oral Maxillofac Surg 1992: 50: 851-7. 18. PETROVIC A, STUTZMAN J, OUDET C. Control processes in postnatal growth of condylar cartilage of the mandible. In: MCNAMARA JA, ed.: Monograph no. 4 Craniofacial Growth Series. Ann Arbor: University of Michigan Press, 1975: 1457. 19. POGRELMA, KABAN LB. The role of the temporalis fascia and muscle flap in temporomandibular surgery. J Oral Maxillofac Surg 1990: 48: 14-19. 20. POSWILLO D. Experimental reconstruction of the mandibular joint. Int J Oral Surg 1974: 3: 400-11. 21. ROWE NL. Ankylosis of the temporomandibular joint. J R Coil Surg Edinb 1982: 27: 209-18. 22. RoY EW, SARNAT BG. Growth rates of costochondral junctions; possible appli-
cations to human disease. Transplant Bull 1956: 3:80 1. 23. S~NAT BG, ENGEL MB. A serial study of mandibular growth after removal of the condyle in the Macaca rhesus monkey. Plast Reconstr Surg 1951: 7: 364-80. 24. SNYDER CC, BENSON AK, SLATER PV. Construction of the temporomandibular joint by transplanting autogenous sternoclavicular joint. South Med J 1971: 64: 807-14. 25. TIDEMAN H, DODDRIDGE M. Temporomandibular joint ankylosis. Aust Dent J 1987: 32:171 7. 26. WARE W, TAYLOR RC. Cartilaginous growth centers transplanted to replace mandibular condyles in monkeys. J Oral Surg 1966: 244: 33-43. 27. WARE WH, BROWN SL. Growth centre transplantation to replace mandibular condyles. J Maxillofac Surg 1981: 9: 508.
Address: David H. Perrott, DDS, MD University of California San Franc&co Department of Oral and Maxillofacial Surgery 521 Parnassus Avenue, Room C-522, Box 0440 San Francisco, CA 94143-0440 USA
Copyright © M u n k s g a a r d 1994 InternationalJournal of
Oral& Max ofacial SurEery ISSN 0901-5027
Aesthetic and reconstructivesurgery
Costochondral graft construction/reconstruction of the ramus/condyle unit: long-term follow-up
David H. Perrott 1, H i r o n o b u U m e d a 1, L e o n a r d B. Kaban 2 1University of California San Francisco,
Department of Oral and Maxillofacial Surgery, San Francisco, CA; 2Department of Oral and Maxillofacial Surgery, Harvard School of Dental Medicine and Department of Oral and Maxillofaciat Surgery, Massachusetts General Hospital, Boston, MA, USA
D. H. Perrott, H. Umeda, L. B. Kaban: Costochondral graft construction~reconstruction of the ramus/condyle unit: long-term follow-up. Int. J. Oral Maxillofac. Surg. 1994," 23:321 328. © Munksgaard, 1994 Abstract. This is a retrospective study of 26 patients (seven growing and 19 nongrowing) who received costochondral grafts (n=33) for construction or reconstruction of the ramus/condyle unit (RCU). Facial appearance, jaw motion, occlusion, contour, and linear growth changes were documented preoperatively, immediately postoperatively, and long-term (>1 year). Average follow-up was 48.6 months for growing and 46.4 months for nongrowing patients. Facial asymmetry and malocclusion were successfully corrected in all patients except for those with hemifacial microsomia, where partial correction was most common. For the growing patients, mean change in R C U length (n=8) during the observation period was +3.1 mm on the constructed/reconstructed side and +3.2 mm on the unoperated side. For nongrowing patients, mean change in the R C U length (n=25) was -5.7 mm for the reconstructed side. Three patients developed lateral contour overgrowth of the articulating surface; no patients developed clinically significant linear overgrowth with malocclusion. The results of this study indicate that a costochondral graft may be used successfully to construct/reconstruct the RCU and that linear overgrowth of the graft does not appear to be a clinical problem with the method described in this paper.
Construction or reconstruction of the mandibular ramus/condyle unit (RCU) for acquired or congenital defects remains a difficult problem in maxillofacial surgery. A successful result requires restoration of proper mandibular length and form, normal motion, occlusal stability, and, in children, subsequent symmetric growth of the mandible. Reconstructive methods using autogenous tissues such as those of metatarsal head 2, fibula26, and sternoclavicular joint 24, and costochondral rib grafts 1'4'13'14'21 have been reported. In addition, alloplastic materials have
been advocated as an alternative to autogenous grafts II. The costochondral graft is the most common autogenous reconstruction method reported in the literature. Investigations by SARNAT & ENGEL23, POSWILLO20, MOSS • SALENTIJN15, WARE & TAYLOR26, PETROVIC et al. 18, FIGUEROA et al. 4, and ELLIS & CARLSON3 have established the biologic basis for its use. There is, however, controversy regarding the growth potential of the grafted RCU, especially in children with post-traumatic and congenital defects 10,14,27. Authors of clinical and
Key words: costochondral graft; temporomandibularjoint reconstruction; temporomandibular joint, condyle replacement. Accepted for publication 12 July 1994
radiographic studies have reported no growth in some cases and excessive growth in others 5,1°,14,16,27. This study assesses the long-term results of costochondral grafting for construction or reconstruction of the R C U in nongrowing and growing patients. Special attention was directed toward obtaining objective documentation of linear changes in the constructed/reconstructed RCU. Material and m e t h o d s
The study population consisted of 26 patients (33 costochondral grafts) who under-
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went construction/reconstruction of the R C U at the University of California San Francisco (UCSF) in 1986-91. Indications for construction/reconstruction included ankylosis, condylar resorption, degenerative joint disease (DJD), or congenital absence of a condyle (Tables 1 and 2). All patients had at least a 1-year follow-up. Facial appearance (symmetry, asymmetry), maximal incisal opening (MIO), occlusion, and contour or linear changes of the operated (abnormal) and unoperated (normal) R C U s were documented by history, physical examination, and measurements on serial panoramic radiographs.
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P e r r o t t et al. were modified by the correction factor if the molar measurement was not equal to that found on the To radiograph.
Results Clinical analysis (Tables 1 and 2)
Preoperative evaluation (To)
Fig. 1. a) Photograph and b) corresponding diagram of costochondral graft (B) secured with screws and temporalis muscle flap (A) lining glenoid fossa.
Construction/reconstruction of the RCU was achieved with the costochondral graft. The cartilage of the graft was contoured to be 2-4 mm thick and round (Fig. 2). Rib graft length was determined by the ramus height discrepancy and the amount of facial asymmetry to be corrected. The lateral ramus and rib were trimmed and contoured to obtain a good bony interface. The superior (cartilaginous) surface of the graft was then placed against the joint lining, and the graft was rigidly secured to the mandible with two or three 2.0-mm or 2.7-mm pretapped bone screws (Figs. 1 and 3). A drain was placed, the incisions closed, and a pressure dressing applied. M M F was maintained for 3-10 days, depending on the thickness and rigidity of the costochondral graft. After release of M M F (mean-10.1--3.4 days), the patients were started on a soft diet and jaw-opening exercises. During the next 3 4 weeks, the diet was advanced to a solid consistency. The physiotherapy program consisted of heat, massage, ultrasonography, gum chewing, manual stretching, and the Bell Dynamic Jaw Exerciser (Walter Lorenz Surgical Instruments, Inc, Jacksonville, FL, USA) or Therabite (Walter Lorenz Surgical Instruments). Six weeks postoperatively (in ankylosis cases), if the patient was not able to achieve the documented intraoperative MIO and showed no signs of improvement, the jaws were stretched under general anesthesia. Patients were followed on a monthly basis for at least 1 year.
Clinical analysis Clinical analysis was completed preoperatively (To), 1 month postoperatively (T1), and long-term (T2). Facial symmetry was docu-
mented by determining the relationship of the chin point to the midsagittal plane and the linear distance from the inferior mandibular border to the zygomatic arch. Occlusion was documented and classified as stable or unstable. Stable occlusion was defined as good interdigitation of all the teeth without signs of prematurities or open bite. MIO was measured with a rigid triangular measuring device placed between the maxillary and mandibular central incisors in the midline. Presence or absence of pain was noted and compared with the preoperative condition.
Radiographic analysis Panoramic radiographs were taken preoperatively (To), immediately postoperatively (T1), and at yearly intervals (T3). Outlines of the constructed/reconstructed and unoperated (normal) RCUs were traced over the radiograph, and direct measurements were made by two, independent investigators. The length of the constructed/reconstructed RCU or unoperated RCU was the perpendicular distance (mm) from a line tangent to the articulating surface to the point of intersection of lines tangent to the posterior and inferior borders of the mandible 7 (Fig. 3a). To compensate for angulation and other procedural differences associated with the use of panoramic radiographs, we used the ratio of unoperated to operated RCU length in unilateral cases and mathematically corrected for magnification in both unilateral and bilateral cases. The mesiodistal measurement of the same right and left molar on the To radiograph was used as a constant reference (Fig. 3a). Linear measurements of the RCUs obtained on subsequent radiographs
T h e 26 patients were analyzed a n d divided into two groups: growing a n d nongrowing. T h e r e were three male a n d four female growing p a t i e n t s (-<16 years of age) with eight involved T M J s (six unilateral, one bilateral) (Table 1). M e a n age at the time o f o p e r a t i o n was 10.59 years (range ~ 1 6 ) . I n d i c a t i o n s for the o p e r a t i o n included post-traum a t i c ankylosis ( n = 4 ) a n d H F M (n = 3). Preoperatively, 6/7 p a t i e n t s h a d a n asymmetric mandible, 0/7 h a d pain, a n d 5/7 h a d unstable occlusion. In the four patients with restricted j a w motion, the m e a n M I O was 14.2 m m (range 1 0 ~ 0 ) . There were four male a n d 15 female n o n g r o w i n g patients ( > 1 6 years old) with 25 involved T M J s (13 unilateral, six bilateral) (Table 2). M e a n age at the time of o p e r a t i o n was 35.64 years (range 20-58.20). I n d i c a t i o n s for the o p e r a t i o n included b o n y or fibrous ankylosis (n=10), c o n d y l a r r e s o r p t i o n (n=4), t r a u m a ( n = l ) , a u t o i m m u n e arthritis ( n = l ) , D J D ( n = 2 ) , a n d t u m o r (n = 1). Preoperatively, 9/19 p a t i e n t s h a d a n asymmetric mandible, 11/19 h a d pain, a n d 9/19 h a d a n u n s t a b l e occlusion. In the 10 patients with restricted jaw m o t i o n , the m e a n M I O was 14.7 m m (range 2-25). In growing patients, the glenoid fossac were lined with native disk (n=3), temporalis muscle/fascia flap (n=3), a n d p e r i c h o n d r i u m ( n = 1). In the n o n growing group, the glenoid fossae were lined with native disk ( n = 8 ) a n d temporalis muscle/fascia flap (n = 17).
Fig. 2. Harvested costochondral graft showing 3-mm cartilaginous cap.
Costochondral grafts in RCU reconstruction
Immediate postoperative follow-up One month postoperatively (T1), the four growing patients who had ankylosis release and reconstruction with costochondral grafts had achieved mandibular symmetry. Three H F M patients had improvement of skeletal symmetry as a result of the constructed RCU. No patients had pain. All patients maintained the surgically created open bite on the operated side. One month postoperatively (T1), all 10 nongrowing patients who underwent correction of asymmetry remained stable. Nine nongrowing patients who were symmetric before surgery remained so. Pain was present but improved in 10/19 patients and absent in the other 9/19 patients. All patients maintained the surgically created open bite on the operated side.
Long-term follow-up In the growing patients, the average long-term follow-up (T2) was 48.6 months (range 24-72). Clinically, there were no signs of linear overgrowth of the constructed/reconstructed RCUs. All three H F M patients remained asymmetric but were significantly improved. Two (one H F M ; one nonH F M ) growing patients developed lateral contour overgrowth of the constructed/reconstructed RCUs (Figs. 4a and b). Lateral contour overgrowth was
defined as an abnormal increase in mass in the region of the costochondral junction. It may be associated with decreased motion, but contour overgrowth is not usually associated with changes in occlusion. The long-term MIO was 36.0 mm (range 27-51) in the four patients with preoperative ankylosis. This long-term change in the MIO was statistically significant (P<0.05), as compared with preoperative measurements. In the nongrowing patients, the average long-term follow-up (T2) was 46.4 months (range 14-40). At the end of the follow-up period, four patients had a clinically visible mandibular asymmetry. Two asymmetries were the result of contralateral (unoperated) condylar resorption, and two were the result of remodeling (a decrease in length) of the reconstructed RCU. No patients showed clinical signs of linear overgrowth. One patient did develop lateral contour overgrowth in the region of the costochondral junction. Of the 12 patients with preoperative pain, six had resolution of the pain and six had improved/manageable pain. Three patients developed unstable occlusion as a result of R C U shortening (n=2) and contralateral R C U resorption (n=l). In the patients with restricted preoperative jaw motion, the mean long-term MIO was 33.9 mm (range 25-49). This change in MIO was statistically significant (P<0.05), as compared with the pre-
325
operative measurements. In patients with normal motion preoperatively, there was no postoperative hypomobility. Radiographic analysis (Tables 1 and 2)
In growing patients (Table 1), the mean change of the constructed/reconstructed R C U (T 2 T1) was -2.8_+4.2 mm (range ~9] [+3]), and for the unoperated R C U it was +3.2 mm (range ~1] [+7]). Three constructed/reconstructed RCUs in two patients (Table 1) increased in length. In patient no. 5 (bilateral), both sides increased equally, as desired. In patient no. 7, the constructed R C U increased in length equal in amount to growth of the unoperated side. However, most of the constructed/reconstructed RCUs (n=5 in five patients) decreased in length. In nongrowing patients (Table 2), the mean change in the reconstructed R C U length (T2 Yl) was 5.7 mm (range [16.0]-[+4.0]) (Table 2). On the unoperated side, there was an insignificant change in length of 0.1 mm. In 22/25 reconstructed RCUs, there was an overall decrease in the reconstructed R C U length as a result of settling and remodeling. In one patient (no. 14), there was an increase in the reconstructed R C U length, while the contralateral reconstructed R C U decreased in length, resulting in a symmetric mandible. In one patient (no. 16), the reconstructed
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Perrott et al. Fig. 4. Sixteen-year-old girl 2 years after treatment of TMJ ankylosis with resection, costochondral graft, and temporalis muscle fascia flap. Patient shows lateral contour overgrowth of left reconstructive RCU (arrow). a) Frontal view showing left, lateral overgrowth of RCU (arrow). b) Frontal view showing good MIO and left, lateral overgrowth (arrow). c) Intraoral photo showing stable occlusion with no open bite or midline shift, d) Intraoperative photo after division of temporalis muscle flap (A) and exposure of RCU. Overgrowth of reconstructed RCU (B) has encompassed original costochondral graft. There is no linear overgrowth, e) Intraoperative photo after removal of lateral overgrowth (B) and maintenance of temporalis muscle (A).
RCU increased by an amount equal to that of the contralateral unoperated RCU. In both the growing and nongrowing patients, the mean dimensional change of the reconstructed RCU and native R C U was not statistically significant (P<0.05). In summary, in both growing (5/8) and nongrowing (22/25) constructed/reconstructed RCUs, there was a mean decrease in length during the follow-up period. Discussion
The costochondral graft is a common method to construct/reconstruct the RCU because it provides: 1) autogenous material without the possibility of a foreign-body reaction, 2) a cartilaginous articulating surface, 3) the possibility of permanent bony union and biologic remodeling in response to function, 4) growth potential. Furthermore, there is minimal donor site morbidity. The disadvantages of this method are a requisite additional surgical procedure and potential associated donor site morbidity. In addition, accurate prediction of linear changes of the constructed/reconstructed RCU has not been possible. It is also difficult to measure accurately and document results of RCU construction/reconstruction because of radiographic limitations. Financial costs and lack of standard head position prohibit the use of coronal computer tomograms. Although cephalograms may be helpful in identifying asymmetries, direct linear measurements of the R C U cannot be done. From a practical standpoint, a panoramic radiograph is useful. Limitations associated with the panoramic
Costochondral grafts in R C U reconstruction
radiograph include nonreproducible head position and resultant distortion and magnification error. In this study, we attempted to compensate for these limitations by using the same panoramic x-ray machine for all radiographs and by calculating a constant mathematic measurement of the right and left molar mesiodistal length. In addition to linear measurements, we used serial ratios of unoperated to operated RCU sides (Tables 1 and 2). Since 1920, when GILLIES first described the use of the costochondral graft to reconstruct a RCU, its use and reported results have remained a focus of great discussion 14. The costochondral graft appears to provide adequate strength and bony continuity for the mandible to function, although there have been reports of the cartilage fracturing from the rib I2'27. In this study, no problems with regard to strength were identified. Postoperative function was excellent except in the patients with lateral contour overgrowth who experienced some decrease in mandibular motion. Two patients did develop an unstable occlusion as a result of shortening, settling, and remodeling of the constructed/reconstructed RCU. Many reports have documented the rationale for use of the costochondral graft for construction/reconstruction of the RCU. The costochondral graft is a growth center and it adapts to function. Initially, its morphologic character does not resemble that of native condylar cartilage; however, it remodels over a period of time and eventually becomes similar to native condylar cartilage3,5,18,20,22,26. The growth of the costochondral graft is controlled by intrinsic (growth centers) and/or extrinsic (functional matrix) factors 6,16'1s. Although there was no clinically significant linear overgrowth of the constructed/reconstructed RCU, we did document contour overgrowth of the articulating surface in a small group of growing and n0ngrowing patients. Lateral contour overgrowth was significant as an aesthetic problem. Although these patients did not develop malocclusion, there was a decreased mandibular motion as reported in other papers 5'13. This finding is important in that the contour overgrowth of the articulating surface may produce deviation of the chin Point toward the normal side by a mass effect on the position of the
jaw while not increasing the linear length of the RCU. The development of asymmetries in four nongrowing patients is an important observation because we usually assume that patient asymmetries are secondary to costochondral graft overgrowth. In two patients, the asymmetry was the result of contralateral condylar resorption. Two of the patients developed asymmetries because of graft resorption, not overgrowth. The pathogenesis is not clear and probably falls into the same category of idiopathic condylar resorption that is seen in the setting of orthognathic surgery. All patients in this study achieved good postoperative MIO. There appeared to be no correlation between MIO and changes in size of the constructed/reconstructed RCU. The role of function in long-term dimensional changes of the constructed/reconstructed R C U remains unclear, especially in patients with congenital deformities such as H F M . MULLII~N et al. suggest that the effect of the functional matrix upon growth of the costochondral graft should rather be deemed one of a dysfunctional matrix in H F M patients 16. Little attention has been directed toward the size of the cartilage cap on the graft and its relation to linear changes. Most reports describe a cartilage length ranging from 0.5 to 2.5 cm 9'27. It has been hypothesized that as much cartilage should be preserved to achieve a growth pattern similar to that of the native condyle and prevent ankylosis 12. In contrast, TIDEMAN & DODDRIDGE25 feel that a smaller cartilage cap prevents a fracture at the costochondral junction and may play a role in diminishing the potential for overgrowth of the graft. This hypothesis is supported by PETRO¥IC et al.'s suggestion that the costochondral graft's growth potential may be enhanced by preserving a larger amount of cartilage, which may be responsive to intrinsic as well as local extrinsic factors is. This is further supported by experimental studies by PELTOMA.K117.
In our study, all patients were constructed/reconstructed with a costochondral graft using only 2-4 mm of cartilage. When growth did occur, it was equal to or less than the unoperated R C U and was not clinically significant. The only clinically significant asymmetry occurred as a result of con-
327
tour changes at the articulating surface. These findings indicate that the length of the cartilage may be an important factor in determining linear and contour changes of the constructed/reconstructed RCU. In conclusion, this long-term retrospective study showed that the costochondral graft is an acceptable method to construct/reconstruct the R C U in growing and nongrowing patients. On average, the constructed/reconstructed R C U decreased in length in both groups. There was no clinically significant linear increase in length of the constructed/reconstructed RCU. Therefore, we recommend overcorrection by creating an open bite on the operated side. This is maintained by an occlusal splint and gradually closed by adjusting the splint after 3 months postoperatively. Further studies are needed to address the effects of cause (congenital in comparison with acquired), specific surgical methods, inherent qualities of the costochondral graft, systemic factors, postoperative function and physiotherapy, muscle, periosteum, and size of the cartilage cap on the long-term growth of the constructed/reconstructed RCU. Assessment of growth must be documented by specific radiographs and measurements. Acknowledgment. This research was in part funded by the University of California San Francisco Oral and Maxillofacial Surgery Research Fund.
References
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hal bone growth. Endocr Rev 1987: 8: 426-38. 7. KABAN LB, MULLIKEN JB, MURRAY JE. Three dimensional approach to analysis and treatment of hemifacial microsomia. Cleft Palate J 1981: 18:90 9. 8. KABAN LB, PERROTT DH, FISHER K. A protocol for management of temporomandibular ankylosis. J Oral Maxillofac Surg 1990: 48: 1145-51. 9. KABAN LB, PERROTT DH. Discussion. Unpredictable growth pattern of costochondral graft. Plast Reconstr Surg 1992: 90: 887-8. 10. KENNETT S. Temporomandibular joint ankylosis: the rationale for grafting in the young patient. J Oral Surg 1973: 31: 744 8. 11. KENT JN, MISIF~KD J, SHEN RK, HrNDS EC, HONSY CA. Temporomandibular joint condylar prosthesis: a ten-year report. J Oral Maxillofac Surg 1983: 41: 245-54. 12. LINDQVIST C, PIHAKARI A, TASANEN A, HAMPF G. Autogenous costochondral grafts in temporomandibular joint arthroplasty. J Maxillofac Surg 1986: 14: 143-9. 13. LINK JO, HOFFMAN DC, LASKIN DM. Hyperplasia of a costochondral graft in an adult. J Oral Maxillofac Surg 1993: 51: 1392-4. 14. MACINTOSH RB, HENNY FA. A spectrum
of application of autogenous costochondral grafts. J Maxillofac Surg 1977: 5: 257 67. 15. Moss ML, SALENTIJN L. The primary role of functional matrices in facial growth. Am J Orthod 1969: 55: 566-77. 16. MULLIK~N JB, FERRARONF, VENTO AR. A retrospective analysis of growth of the constructed condyle-ramus in children with hemifacial microsomia. Cleft Palate J 1989: 26: 312-17. 17. PELTOMAKIT. Growth of a costochondral graft in the rat temporomandibular joint. J Oral Maxillofac Surg 1992: 50: 851-7. 18. PETROVIC A, STUTZMAN J, OUDET C. Control processes in postnatal growth of condylar cartilage of the mandible. In: MCNAMARA JA, ed.: Monograph no. 4 Craniofacial Growth Series. Ann Arbor: University of Michigan Press, 1975: 1457. 19. POGRELMA, KABAN LB. The role of the temporalis fascia and muscle flap in temporomandibular surgery. J Oral Maxillofac Surg 1990: 48: 14-19. 20. POSWILLO D. Experimental reconstruction of the mandibular joint. Int J Oral Surg 1974: 3: 400-11. 21. ROWE NL. Ankylosis of the temporomandibular joint. J R Coil Surg Edinb 1982: 27: 209-18. 22. RoY EW, SARNAT BG. Growth rates of costochondral junctions; possible appli-
cations to human disease. Transplant Bull 1956: 3:80 1. 23. S~NAT BG, ENGEL MB. A serial study of mandibular growth after removal of the condyle in the Macaca rhesus monkey. Plast Reconstr Surg 1951: 7: 364-80. 24. SNYDER CC, BENSON AK, SLATER PV. Construction of the temporomandibular joint by transplanting autogenous sternoclavicular joint. South Med J 1971: 64: 807-14. 25. TIDEMAN H, DODDRIDGE M. Temporomandibular joint ankylosis. Aust Dent J 1987: 32:171 7. 26. WARE W, TAYLOR RC. Cartilaginous growth centers transplanted to replace mandibular condyles in monkeys. J Oral Surg 1966: 244: 33-43. 27. WARE WH, BROWN SL. Growth centre transplantation to replace mandibular condyles. J Maxillofac Surg 1981: 9: 508.
Address: David H. Perrott, DDS, MD University of California San Franc&co Department of Oral and Maxillofacial Surgery 521 Parnassus Avenue, Room C-522, Box 0440 San Francisco, CA 94143-0440 USA