Diagnosis Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 36–38 (DOI: 10.1159/000350600)
Development of Rib Cartilage Masanao Oki · Hirotaki Asato Department of Plastic Surgery, Dokkyo Medical University, Tochigi, Japan
Use of Rib Cartilage in Microtia Surgery
We use rib cartilage in microtia surgery for the following three purposes: (1) as a framework for the initial surgery (rib cartilage graft), (2) as a buttress for the elevated auricle in the second surgery (auricular elevation), and (3) as a column (columella) for connecting the reconstructed eardrum and the auditory ossicles during reconstruction of the EAC in the second surgery. It is important to harvest sufficient cartilage for the former two purposes because a column can be made with only a small portion of a cartilage. We harvest the 6th, 7th and 8th rib cartilages in the initial surgery.
A chest circumference of 60 cm is a guide to a sufficient amount of rib cartilage for the purposes mentioned above, and surgery is usually considered when a patient has grown enough to meet this criterion. We have found through daily clinical practice that the chest circumference reaches approximately 60 cm at the age of 10 years in most microtia patients in Japan. The typical physique of microtia patients at this age is 130–135 cm in height and 30 kg in body weight. In general, the lengths of the 6th, 7th and 8th rib cartilages, which could be harvested during initial surgery, are 7, 10 and 12 cm, respectively (fig. 1). This would be sufficient for this purpose.
Downloaded by: Washington University 198.143.32.1 - 3/24/2016 3:12:47 PM
Growth of Rib Cartilage
Fig. 1. The 6th, 7th and 8th rib cartilages fully harvested during surgery.
a
b
Development of Rib Cartilage Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 36–38 (DOI: 10.1159/000350600)
37
Downloaded by: Washington University 198.143.32.1 - 3/24/2016 3:12:47 PM
Fig. 2. a Auricular framework made of rib cartilages harvested from a 10-year-old male patient. b Auricular framework made of rib cartilages harvested from a 52-year-old male patient.
Ossification of Rib Cartilage
Rib cartilage usually starts ossifying at adolescence, although the actual timing of ossification varies among patients. The process of ossification also varies and some authors note a difference based on sex [1]. Ossification starts with the first rib cartilage and progresses up to the 12th cartilage. Ossified rib cartilages are hard and brittle, and making a framework gets more difficult in elderly patients (fig. 2).
Points to Note on Preoperative Evaluation of Rib Cartilage
Attention should be paid to the following two points in preoperative evaluation of rib cartilage: (1) rib cartilage may not be sufficiently grown in patients with thick subcutaneous fat even if the chest circumference exceeds 60 cm, and (2) the length of the 8th cartilage may be too short for the growth of the thorax in some patients, although this length is particularly important because the 8th cartilage is used to create the helix, the longest structure of the ear. These variations can usually be compensated for, but preoperative simulations using computer-assisted technology have been reported [2] and are worth considering for some patients.
References 2 Kaneko T, Takano J, Kobayashi M, Nakajima T, Fujino T: Computer-aided surgery and tissue expansion in auricular reconstruction for microtia. Keio J Med 2001;50(suppl 2):109–119.
Masanao Oki Department of Plastic Surgery, Dokkyo Medical University 880 Kitakobayashi, Mibu-Machi, Shimotsuga-gun Tochigi 320-0293 (Japan) E-Mail [email protected]
38
Oki · Asato Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 36–38 (DOI: 10.1159/000350600)
Downloaded by: Washington University 198.143.32.1 - 3/24/2016 3:12:47 PM
1 Rejtarova O, Slizova D, Smoranc P, Rejtar P, Bukac J: Costal cartilages – a clue for determination of sex. Biomed Papers 2004;148:241–243.
Development of Rib Cartilage Masanao Oki · Hirotaki Asato Department of Plastic Surgery, Dokkyo Medical University, Tochigi, Japan
Use of Rib Cartilage in Microtia Surgery
We use rib cartilage in microtia surgery for the following three purposes: (1) as a framework for the initial surgery (rib cartilage graft), (2) as a buttress for the elevated auricle in the second surgery (auricular elevation), and (3) as a column (columella) for connecting the reconstructed eardrum and the auditory ossicles during reconstruction of the EAC in the second surgery. It is important to harvest sufficient cartilage for the former two purposes because a column can be made with only a small portion of a cartilage. We harvest the 6th, 7th and 8th rib cartilages in the initial surgery.
A chest circumference of 60 cm is a guide to a sufficient amount of rib cartilage for the purposes mentioned above, and surgery is usually considered when a patient has grown enough to meet this criterion. We have found through daily clinical practice that the chest circumference reaches approximately 60 cm at the age of 10 years in most microtia patients in Japan. The typical physique of microtia patients at this age is 130–135 cm in height and 30 kg in body weight. In general, the lengths of the 6th, 7th and 8th rib cartilages, which could be harvested during initial surgery, are 7, 10 and 12 cm, respectively (fig. 1). This would be sufficient for this purpose.
Downloaded by: Washington University 198.143.32.1 - 3/24/2016 3:12:47 PM
Growth of Rib Cartilage
Fig. 1. The 6th, 7th and 8th rib cartilages fully harvested during surgery.
a
b
Development of Rib Cartilage Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 36–38 (DOI: 10.1159/000350600)
37
Downloaded by: Washington University 198.143.32.1 - 3/24/2016 3:12:47 PM
Fig. 2. a Auricular framework made of rib cartilages harvested from a 10-year-old male patient. b Auricular framework made of rib cartilages harvested from a 52-year-old male patient.
Ossification of Rib Cartilage
Rib cartilage usually starts ossifying at adolescence, although the actual timing of ossification varies among patients. The process of ossification also varies and some authors note a difference based on sex [1]. Ossification starts with the first rib cartilage and progresses up to the 12th cartilage. Ossified rib cartilages are hard and brittle, and making a framework gets more difficult in elderly patients (fig. 2).
Points to Note on Preoperative Evaluation of Rib Cartilage
Attention should be paid to the following two points in preoperative evaluation of rib cartilage: (1) rib cartilage may not be sufficiently grown in patients with thick subcutaneous fat even if the chest circumference exceeds 60 cm, and (2) the length of the 8th cartilage may be too short for the growth of the thorax in some patients, although this length is particularly important because the 8th cartilage is used to create the helix, the longest structure of the ear. These variations can usually be compensated for, but preoperative simulations using computer-assisted technology have been reported [2] and are worth considering for some patients.
References 2 Kaneko T, Takano J, Kobayashi M, Nakajima T, Fujino T: Computer-aided surgery and tissue expansion in auricular reconstruction for microtia. Keio J Med 2001;50(suppl 2):109–119.
Masanao Oki Department of Plastic Surgery, Dokkyo Medical University 880 Kitakobayashi, Mibu-Machi, Shimotsuga-gun Tochigi 320-0293 (Japan) E-Mail [email protected]
38
Oki · Asato Kaga K, Asato H (eds): Microtia and Atresia – Combined Approach by Plastic and Otologic Surgery. Adv Otorhinolaryngol. Basel, Karger, 2014, vol 75, pp 36–38 (DOI: 10.1159/000350600)
Downloaded by: Washington University 198.143.32.1 - 3/24/2016 3:12:47 PM
1 Rejtarova O, Slizova D, Smoranc P, Rejtar P, Bukac J: Costal cartilages – a clue for determination of sex. Biomed Papers 2004;148:241–243.
