Epidermoid Cyst of Orbit Requiring Cranialization of Frontal Sinus.

How often do intracranial epidermoid cysts occur?Is a coronary incision necessary?What are the steps of the procedure, difficulties encountered, and process for circumventing those difficulties?What is the follow-up protocol and outcome?

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.

Usefulness of customized titanium plates for midface contouring surgery.

INTRODUCTION AND IMPORTANCE: In our department, we have been performing bone reconstructions on a case-by-case basis using vascularized free tissue transfers and custom-made artificial bones (HA). While these procedures have specific advantages, they are also limited in terms of the invasiveness as well as the stability and strength of implants. In the present study, we describe the use of a CTP to achieve minimally invasive midface plastic surgery with the superior moldability of a 3D structure and reliable stability compared to the use of autologous tissue. CASE PRESENTATION: A total of three patients were included in the study. The patients (all female, ages: 66, 18, and 35 years) had bone malformation or hemifacial microsomia following surgery for maxillary cancer or multiple facial fractures. Based on DICOM data from preoperative CT, 3D models were created on a computer using CAD/CAM techniques. The models were compared in simulations to determine the optimal structure. These 3D models were used in additive manufacturing systems to create custom-made titanium alloy plates for facial reconstruction. CLINICAL DISCUSSION: Although the amount of soft tissue was insufficient in some cases, all patients were able to maintain the desired morphology without developing any complications such as infections, significant soft tissue atrophy, or implant failure. CONCLUSION: Our CTP model created by CAD/CAM was effective in contouring surgery of the midface as it had the superior stability and biocompatibility of titanium. Changes to the soft tissue should also be considered in order to further improve the procedure.

Hardness of Artificial Bone and Vulnerability of Reconstructed Skull-A Biomechanical Study.

Background: Various materials are used to reconstruct cranial defects. The present study focuses on what happens when reconstructed skulls are impacted in trauma situations. Using biomechanical analysis, the present study elucidates how the hardness of reconstruction material affects the vulnerability of reconstructed skulls. Methods: A 3-dimensional finite element model was produced simulating the skull of an intact adult male. A defect was made on the left hemi-frontal part of the skull model. The defect was restored with artificial bone with 3 different hardness models. These models were respectively defined as Hard Model (simulating reconstruction with titanium), Moderate Model (simulating reconstruction with a material equivalent to human bone), and Soft Model (simulating reconstruction with hydroxyl apatite). Virtual impacts were applied on these models in 9 patterns, and the conditions of subsequent fracture were evaluated using finite element analysis. For each of the 9 impact patterns, the conditions of subsequent fracture were compared among the 3 models. Results: In 8 of the 9 impact patterns, the condition of fracture was more widespread for Hard Model than for Moderate Model and Soft Model. Conclusions: Skulls reconstructed with a hard material can develop serious fracture if they are impacted again. Therefore, usage of hard materials should be avoided to prevent serious injuries from secondary trauma.

Influence of Periosteum Location on the Bone and Cartilage in Tissue-Engineered Phalanx.

PURPOSE: This study investigated the influence of periosteal tissue of different origins on the calcification at the diaphysis and chondrocyte maturation at the epiphysis in an engineered phalanx. We hypothesized that the periosteum from long bones would better provide donor cells for bone formation and signals for maturation of the joint cartilage. METHODS: Periosteum was harvested from 4 locations (cranium, mandible, radius, and ilium) of calf bones. A human phalangeal bone-shaped, biodegradable, 3-dimensional scaffold hydroxyapatite-poly L-lactic-ɛ-caprolactone (HA-P[LA/CL]) was prepared using a human phalangeal bone-shaped template. A bioengineered human phalanx was fabricated by combining periosteal grafts with biodegradable copolymers. The joint cartilage region (chondrocyte/polyglycolic acid [PGA] composite) was subsequently sutured to the phalangeal bone region (periosteum/HA-P[LA/CL] composite) with absorbable sutures to make a human phalangeal bone model. These were then implanted in nude mice for maturation of the constructs. Macroscopic, radiographic, histological, and immune-histochemical evaluations were carried out to determine the relative influence of the periosteal graft source on bone and cartilage formation at 10 and 20 weeks after implantation. RESULTS: Calcification localized under the periosteum was noted in the cranium, radius, and ilium groups after 10 weeks, which markedly expanded at the modelled diaphysis after 20 weeks. The width in the minor axis direction tended to increase with time after grafting in the cranium group, whereas the longitudinal length increased in the radius and ilium groups. The joint cartilage thickness changed with time depending on the type of periosteum, and periosteum collected from the radius and ilium was associated with the greatest cartilage thickness in the joint cartilage maturation process. CONCLUSIONS: These results suggest that periosteum collected from radius of calves demonstrated superior bone formation and chondrocyte maturation in the engineered phalanx compared with other sources of periosteum. CLINICAL RELEVANCE: The osteogenic capacity depends on the periosteal source regardless of intramembranous or endochondral ossification. The appropriate periosteal choice is essential in the phalangeal bone and cartilage tissue engineering. The results are important for broadening tissue engineering possibilities for clinical application.

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.

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.

Biomechanical analysis of likelihood of optic canal damage in peri-orbital fracture.

PURPOSE: Detection of optic canal fractures is often difficult because of the subtleness of the fracture. If we could clarify impact on which region around the orbit is likely to accompany the fracture of the optic canal, the knowledge should be useful to make early diagnosis of optic canal fractures. The present study was conducted to elucidate this issue. METHODS: Ten finite element models were produced simulating the skulls of ten humans (8 males and 2 females; 43.8 ± 10.2 y/o). The peri-orbital area of each of the ten models was divided into eight regions in a clockwise fashion per 45 degrees. These regions were defined as Superior-Medial (0-45 degrees), Medial-Superior (45-90 degrees), Medial-Inferior (90 to 135 degrees), Inferior-Medial (135 to 180 degrees), Inferior-Lateral (180-225 degrees), Lateral-Inferior (225 to 270 degrees), Lateral-Superior (270-315 degrees), and Superior-Lateral regions (315-360 degrees), respectively. Dynamic simulation of applying traumatic energy on each of these regions was conducted. Resultant fracture patterns were evaluated using finite element analyses. Thereafter, frequencies of fracture involvement of the optic canal were evaluated for each of the eight regions. RESULTS: The involvement of the optic canal was most frequent for the Superior-Medial region (7/10), followed by the Medial-Superior region (5/10). CONCLUSION: Optic canal fracture is likely to occur when the area between the supra-orbital notch and the medial canthus are strongly impacted. When evident fracture or serious damage of soft tissue is observed in this area, occurrence of optic canal fracture should be suspected.

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.

Thoracic outlet syndrome after the Nuss procedure for pectus excavatum: Is it a rare complication?

OBJECTIVE: The present study aims to elucidate the frequency of thoracic outlet syndrome after the Nuss procedure for pectus excavatum and the conditions in which thoracic outlet syndrome is likely to develop. METHODS: A retrospective study including 85 pectus excavatum patients (58 males and 27 females) was conducted. Thoracic outlet syndrome was defined as a condition in which the patient has numbness, lassitude, or pain of the upper limbs at rest or during motion of the upper limbs. The frequency of the thus-defined thoracic outlet syndrome was evaluated in 85 patients. Age, sex, Haller indices, and the positions of the correction bars were compared between the patients who developed thoracic outlet syndrome and those who did not. RESULTS: Preadolescent patients (18 out of 85) did not develop postoperative thoracic outlet syndrome. In total, 15.2% of adult male patients (7 out of 46) and 33% of adult female patients (7 out of 21) developed postoperative thoracic outlet syndrome. For both male and female groups, Haller indices were significantly greater for patients who had postoperative thoracic outlet syndrome than for those who did not. Correction bars were generally placed at higher intercostal spaces in patients who developed postoperative thoracic outlet syndrome than in those who did not. CONCLUSION: A considerable percentage of adult patients develop thoracic outlet syndrome after the Nuss procedure for pectus excavatum. Maturity of the thoracic wall, femininity, severity of the deformity (represented by greater Haller indices), and placement of correction bars at superior intercostal spaces are risk factors for postoperative thoracic outlet syndrome.

A biomechanical study of relationship between sternum defect patterns and thoracic respiration.

BACKGROUND: Various types of sternum defects are produced after the removal of thoracic tumors involving the sternum. The present study aims to elucidate the relationship between the defect patterns and their effects on thoracic respiration. METHODS: Ten sets of finite element models were produced simulating thoraces of 10 persons and termed normal models. With each of the 10 normal models, the sternum was removed in six different ways to produce new models termed defect models. Defect models were categorized into hemi-superior (H-S), hemi-inferior (H-I), hemi-whole length (H-W), bilateral-superior (B-S), bilateral-inferior (B-I), and bilateral-whole length (B-W) defect types, depending on the locations of the defects. Respiratory movement was dynamically simulated with these models. The volume change the thoraces present during respiration was measured to evaluate the effectiveness of thoracic respiration. This value - defined as ΔV - was calculated and was compared between normal and defect models. RESULTS: With H-W and B-W type models, ΔV dropped to around 20% of normal values. With H-S and B-S type models, ΔV dropped to around 50% of normal values. With H-I and B-I type models, ΔV presented values almost equivalent to those of normal models. CONCLUSION: Effectiveness of thoracic respiration is seriously impaired when the whole length of the sternum is absent. Reconstruction of the defect is essential for these cases. However, since the upper part of the sternum is most important for effective thoracic respiration, priority should be placed on the upper part in performing reconstruction.

Image analysis of the inferior rectus muscle in orbital floor fracture using cine mode magnetic resonance imaging.

PURPOSE: The main cause of diplopia induced by orbital floor fracture is strangulation or damage of the extraocular muscles, and the outcome varies depending on the severity of trauma. In this study, we evaluated the dynamics of the eyeball and inferior rectus muscle based on cine magnetic resonance (MR) images acquired before surgery. The preoperative images and outcomes were retrospectively investigated. MATERIAL AND METHODS: The subjects were 20 patients with orbital floor fracture. The patients repeated upgaze and downgaze, and images of these were acquired using cine mode magnetic resonance imaging (MRI). Image series were obtained in the sagittal direction including the eyeball and long axis of the optic nerve. The eyeball rotation angle, strangulation, and morphology of the inferior rectus muscle were evaluated in each phase. RESULTS: On cine mode MRI, the outcome was poor in cases with a maximal inferior rectus muscle thickness of 5 mm or greater on extension (two or more times thicker than on the healthy side). CONCLUSIONS: Our results suggest that the development of sequelae can be predicted by preoperative image analysis using cine MRI, which may be beneficial to help surgeons understand the mechanism of contracture.

Irregular location of major pectoral muscle can be a causative factor of pectus excavatum.

Pectus excavatum-commonly known as funnel chest-is one of the most frequently observed congenital deformities, in which the patients' thoraces present concavity. This paper presents our original hypothesis that the abnormal positioning of the major pectoral muscle can be a potential factor in the occurrence of pectus excavatum, and evaluates the validity of the hypothesis by performing an anatomical and a biomechanical study. An anatomical study on clinical cases revealed that the major pectoral muscle tends to be positioned more superiorly in pectus excavatum patients than in normal persons. The biomechanical study, using three-dimensional finite element dynamic simulation, revealed that the major pectoral muscle functions to elevate the sternum and that the elevating effect is reduced when the muscle is located at superior regions on the thoracic wall. These findings support our hypothesis that the abnormal position of the major pectoral muscle is a potential causative factor for pectus excavatum. This hypothesis suggests that, during surgical correction of pectus excavatum with an open approach, surgeons should reposition the major pectoral muscle to its correct anatomical position to avoid recurrence.

Long-term result of a biodegradable osteo-inductive copolymer for the treatment of orbital blowout fracture.

PURPOSE: We have recently reconstructed the orbital wall using a bioabsorbable osteo-inductive copolymer as a support material for the bone defects in patients with orbital blowout fracture. The purpose of this study was to investigate a 2-year follow-up after implantation. MATERIAL AND METHODS: In order to investigate the efficacy and safety of the bioabsorbable osteo-inductive copolymer HA-P(LA/CL), hydroxyapatite-poly(l-lactide-ε-caprolactone), we measured CT density of the implanted copolymers in 7 patients at such time points as 1 week, 6 months and 2 years after surgery along with the long-term outcomes with regard to postoperative complications. RESULTS: Five patients in whom the intraoperative maximum width of the bone defect was less than 15 mm demonstrated the fracture types of either linear or trap-door. All patients treated with HA-P(LA/CL) copolymer indicated good bone formation with high CT density (>500) at 2 years postoperatively. In contrast, 2 patients in whom the intraoperative maximum width of the bone defect was more than 16 mm demonstrated a punched-out type fracture. Postoperative CT of the HA-P(LA/CL) copolymer showed low density (28.0 and 173.4) at 2 years postoperatively, indicative of limited bone formation. None of the cases demonstrated significant postoperative complications such as diplopia, enophthalmos, infection and extrusion of the implant material. CONCLUSION: The results of this study demonstrate that surgical treatment of orbital blowout fractures using bioabsorbable osteo-inductive copolymer was useful in linear and trap-door fractures.

CASE REPORT How to Repair the Lower Eyelid Retraction, Resulting From the Primary Surgery for Epiblepharon?

OBJECTIVE: Among the surgical procedures used to correct the positions of the eyelids or improve their cosmetic appearance, procedures for treating eyelid retraction are some of the most challenging. Lower eyelid retraction can occur iatrogenically after various surgical procedures. We performed a successful corrective procedure for lower eyelid retraction, which had occurred at some point in the 2 decades after primary surgery for epiblepharon. METHOD: A 23-year-old woman underwent primary surgery for bilateral epiblepharon at the age of 5 years. However, at the age of 17, she noticed that an abnormally large proportion of her right sclera was visible when her eyes were in their natural position. In the primary position of gaze, the distance from the lower limbus of the right cornea to the upper margin of the lower eyelid was approximately 2 mm. An incision was made in the lower eyelid along the scar caused by the previous operation. Subsequently, the connections between the tarsus and the lower eyelid retractors were broken, and harvested auricular cartilage was placed between the lower edge of the tarsus and the lower eyelid retractors. RESULTS: One year after the operation, there was no gross difference in the distance between the lower margin of the corneal limbus and the lower eyelid on either side, and the patient was extremely happy with the results. CONCLUSION: Using a novel surgical technique, we successfully lengthened the posterior layer of the lower eyelid retractors with a small amount auricular cartilage, resulting in good functional and cosmetic outcomes.

Association between preoperative inferior rectus muscle swelling and outcomes in orbital blowout fracture.

PURPOSE: In 18 patients with orbital blowout fracture who underwent reconstruction using a bone autograft, the association between preoperative inferior rectus muscle swelling and the outcome 1 year after the operation was evaluated. MATERIAL AND METHODS: The patients were classified according to outcomes into four groups: Group A without double vision showing normal ocular movements, Group B with double vision showing normal ocular movements, Group C with double vision showing improvement in ocular movements, and Group D with double vision showing no improvement in ocular movements. Inferior rectus muscle swelling was evaluated by calculating its swelling rate on the injured compared with the non-injured side on preoperative coronal CT images. RESULTS: Concerning outcomes, 12, 2, and 4 patients were classified as Groups A, B, and C, respectively, and no patient was classified as Group D. The inferior rectus muscle swelling rate was ≤1.2 in Group A, and 1.6-2.4 in Groups B and C. CONCLUSION: In patients in whom inferior rectus muscle swelling on the injured is ≥1.6 times that on the non-injured side on preoperative coronal CT images, double vision and slight impairment of eye movements may remain after surgery.

Analysis of the orbital floor morphology.

INTRODUCTION: For the repair of large orbital floor defects due to blow-out fractures or those involved by tumours, it is necessary to understand the detailed morphology. The purpose of the present study was to elucidate how age and gender affect its three-dimensional morphology. METHODS: The 3-D computer tomography data of 305 orbits of 182 patients were included in the study. Using the CT data, the orbital floor angle (the angle between the orbital floor and the horizontal plane) and the location of the most inferior point of the orbital floor were measured. Patients were classified into subgroups according to their gender and age. Data were compared among the subgroups. RESULTS: The orbital floor angle was greater in males than in females, and in children than in adults. The location of the lowest point of the orbital floor moves postero-inferiorly with increasing age. CONCLUSION: The present study demonstrated that gender and age affects morphology of the orbital floor. These findings should be useful for reconstruction of the orbital floor.