Frontal Bone Fracture Patterns Suggesting Involvement of Optic Canal Damage.

PURPOSE: Fracture of the frontal bone can be accompanied by damage to the optic canal. The present study uses finite element analysis to identify fracture patterns, suggesting the involvement of the optic canal. METHODS: Ten finite-element skull models were generated from computer tomography data of 10 persons. Then, dynamic analyses simulating collision of a 2-cm-radius brass ball to 6 regions on the frontal bone in the 10 models were performed. Fracture patterns presented by the frontal bone in the 60 experiments were observed, and all those involving the optic canal were selected. Commonalities of the selected fracture patterns were identified. RESULTS: Fracture of the optic canal was observed in 9 of the 60 patients. In all 9 patients, fracture existed on the anterior and posterior walls of the frontal sinus and on the superior orbital wall. CONCLUSION: When the anterior and posterior walls of the frontal sinus and the superior orbital wall are all broken, the optic canal is highly likely to be involved in the damage. When this pattern is observed in emergency examination, preventive decompression of the optic nerve should be considered to avoid potential occurrence of blindness.

Separation of the seventh costal-sternal junction-A new technique to improve outcomes for the Nuss procedure for pectus excavatum.

BACKGROUND: In the standard Nuss procedure for pectus excavatum, the costal arch is often elevated together with the sternum, resulting in unevenness of the lower part of the thorax. This complication is commonly called rib flaring. This paper presents a technique to avoid rib flaring and evaluates its effectiveness. MATERIALS AND METHODS: In our technique, a part of the seventh costal cartilage is removed, disconnecting the costal arch from the sternum. The effectiveness of this technique was evaluated in a retrospective clinical study of 63 pectus excavatum patients who were randomly collected and were divided into two groups. One group-defined as the Standard Group-includes 27 patients (29.8 ± 6.5SD y/o) on whom standard Nuss procedure was conducted; the other group-defined as the Separation Group-includes 36 patients (31.8 ± 6.1SD y/o) on whom the cartilage removal was conducted in addition to the standard Nuss procedure. The degree of postoperative costal-arch elevation was defined as ECA (Elevation of Costal Arch) and was compared between the two groups. RESULTS: ECA was significantly greater for the Standard Group (10.2 ± 3.3SD mm) than for the Separation Group (-1.1 ± 3.42SDmm). CONCLUSION: Postoperative protrusion of the costal arch is prevented by the separation of the seventh costal cartilage from the sternum. Our original technique is a useful option for the treatment of pectus excavatum.

Bone-cartilage proportion in deformed ribs of male pectus excavatum patients.

This study verifies the hypothesis that bone/cartilage proportion in deformed ribs of male pectus excavatum patients varies according to their ages. Anatomical evaluation of the thoraces was performed for 79 male pectus excavatum patients, referring to their three-dimensional computer-tomographic images. The patients were divided into Child Group (5-9 years old: n = 35); Adolescent Group (12-15 years old: n = 15) and Adult Group (18+ years old: n = 29). For each patient, the most concave point of the sternum was identified and the pair of ribs closest to the point were defined as Key Ribs. On each Key Rib, the most ventral point was defined as Prominent Point (PP); the junction between the bone and cartilage was defined as Costo-Chondral Junction (CCJ). The distances of these points from the spine were defined as Distance of Prominent Point (DPP) and Distance of Costo-Chondral Junction (DCCJ), respectively. The horizontal length of the Key Rib was defined as Rib Length (RL). Inter- and intra-group comparisons were performed for DPP/RL and DCCJ/RL. Inter-Group Comparison: DCCJ/RL is significantly smaller and DPP/RL is significantly greater in Adult Group than in Child Group, meaning CCJs shift medially and PPs shift laterally as patients get older. Intra-Group Comparison: In Child Group, DCCJ/RL is significantly greater than DPP/RL, meaning CCJs exist lateral to PPs. Contrarily, in Adult Group, DCCJ/RL is significantly smaller than DPP/RL, meaning CCJs exists medial to PPs. Bone/cartilage proportion in the concave part of the chest shifts according to patients' ages. To perform the Nuss procedure effectively, this age-related anatomical change must be taken into consideration.

Separation patterns of orbital wall and risk of optic canal injury in Le Fort 3 osteotomy.

PURPOSE: The authors hypothesized that the risks of optic canal injury in down-fracturing after Le Fort 3 osteotomy vary depending on the separation patterns of the orbital walls. This study verifies this hypothesis using biomechanical simulation. METHODS: Ten finite-element skull models were produced using computer tomography data from ten persons. These models were modified to simulate Le Fort 3 osteotomy models by removing junctions between the neurocranium and facial cranium. The separation of the orbital wall was performed in four differing ways. In Type 1, all walls were completely separated. In Type 2, only the lateral wall was separated. In Type 3, the inferior wall was left unseparated. In Type 4, the lateral wall was left unseparated. Biomechanical simulation of down-fracturing was performed on the resulting 40 models. By observing irregular fractures occurring inside the orbit, the rate of optic canal involvement was evaluated for each of the four orbital-wall separation patterns. RESULTS: The rates of optic canal involvement were: Type 1 (0/10), Type 2 (0/10), Type 3 (0/10), and Type 4 (4/10). CONCLUSION: When the lateral wall is incompletely separated in Le Fort 3 osteotomy, irregular fracture can develop inside the orbit and involve the optic canal during the down-fracturing process. Hence, the lateral orbital wall should be completely separated to avoid potential blindness due to optic canal injury.

Normobaric oxygen therapy increases cartilage survival ratio in auricular composite grafting in rat models.

PURPOSE: This study aims to clarify whether normobaric oxygen therapy improves the survival of auricular composite grafts in rats. METHODS: For 10 male SD rats, 1.5 cm2 composite grafts were harvested from bilateral ear regions including whole auricles. The harvested grafts were transferred caudally and sutured there. The 10 rats were randomly divided into two groups and kept for 21 days in two different circumstances. The first group (Control group: five rats carrying 10 grafts) was kept in room air (20% oxygen) throughout the 21 days, and the second group-named NBO (normobaric oxygen) group (five rats carrying 10 grafts)-was kept in normobaric 60% oxygen for 3 days and then in room air for 18 days. All the 10 rats were sacrificed on the 21st day. Surviving areas of the grafts and the height of the surviving auricular cartilage were examined for statistical comparison of the two groups. Furthermore, the conditions of chondrogenesis occurring around the perichondrium were compared between the two groups. RESULTS: Surviving areas did not present statistically significant differences between the two groups. The height of surviving cartilage was significantly greater for the NBO group (2610 ± 170 SD µm) than that for the Control group (1720 ± 190 SD µm). Chondrogenesis occurred at positions more distant from the recipient bed in the NBO group than that in the Control group. CONCLUSION: Normobaric oxygen therapy increases the thickness of surviving cartilage in auricular composite grafting in rats, thus suggesting that NBO therapy may also be effective in composite grafting for humans.