Resolution of 3D bioprinting inside bulk gel and granular gel baths.

Three-dimensional (3D) bioprinting has rapidly developed in the last decade, playing an increasingly important role in applications including pharmacokinetics research, tissue engineering, and organ regeneration. As a cutting-edge technology in 3D printing, gel bath-supported 3D bioprinting enables the freeform construction of complex structures with soft and water-containing materials, facilitating the in vitro fabrication of live tissue or organ models. To realize in vivo-like organs or tissues in terms of biological functions and complex structures by 3D printing, high resolution and fidelity are prerequisites. Although a wide range of gel matrices have recently been developed as supporting materials, the effect of bath properties and printing parameters on the print resolution is still not clearly understood. This review systematically introduces the decisive factors for resolution in both bulk gel bath systems and granular microgel bath systems, providing guidelines for high-resolution 3D bioprinting based on bath properties and printing parameters.

Precision Analysis of Supraorbital Transcranial Exits Using Three Dimensional Multidetector Computed Tomography.

PURPOSE: Anatomical variation in supraorbital transcranial exits, which can be divided into the lateral supraorbital exit and the medial frontal exit, has been investigated in several studies during the past few decades. However, in previous studies, inconsistent criteria were used for classifying those exits. The authors analyzed variations in supraorbital transcranial exits using 3 dimensional multidetector computed tomography (3D MDCT), and present a consistent classification of the types of those exits with precise location measurements. METHODS: In 1181 patients (2362 orbits) who underwent facial 3D MDCT, the authors measured a set of qualitative and quantitative parameters. The qualitative parameters included an assessment of the location and type of the exit, and the number of accessory foramina. The quantitative parameters included various distance measurements. RESULTS: A frontal exit was present in 2071 orbits and a supraorbital exit in 953. Neither a frontal exit nor a supraorbital exit was found in 11 orbits. The most common type of frontal exit was the notch type, followed by the foramen type and none. The mean distance from the nasion to the frontal exit was 24.70 ± 3.50 mm on the right side and 23.69 ± 3.42 mm on the left side. CONCLUSION: In conclusion, various types of supraorbital transcranial exits were observed, of which the frontal notch was the most common. This is the first study to conduct a consistent analysis of a large sample of skulls to characterize the distribution of supraorbital transcranial exit types using a comprehensive and clear set of criteria.

Terasakiella salincola sp. nov., a marine alphaproteobacterium isolated from seawater, and emended description of the genus Terasakiella.

A Gram-reaction-negative, S-shaped, motile, poly-ß-hydroxybutyrate-accumulating, facultatively anaerobic, beige-pigmented bacterium, designated strain KMU-80T, was isolated from seawater collected from the Republic of Korea. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the novel isolate was affiliated with the family Methylocystaceae, of the class Alphaproteobacteria, and that it possessed the greatest sequence similarity (96.7 %) to Terasakiella pusilla NBRC 13613T. The DNA G+C content of KMU-80T was 48.3 mol%, and ubiquinone 10 was the sole respiratory quinone. The predominant cellular fatty acids consisted of C18 : 1ω7c (60.2 %), C16 : 0 (13.4 %) and C16 : 1ω7c and/or C16 : 1ω6c (11.1 %). Strain KMU-80T had phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminolipid, an unidentified phospholipid and four unidentified lipids as polar lipids. Based on its distinct phylogenetic position and the combination of genotypic and phenotypic characteristics, this strain is considered to represent a novel species of the genus Terasakiella, for which the name Terasakiella salincola sp. nov. is proposed. The type strain of T. salincola sp. nov. is KMU-80T (= KCCM 90274T = NBRC 112846T). An amended description of the genus Terasakiella is also provided.

Orbital Wall Restoring Surgery for Inferomedial Blowout Fracture.

Repairing a large inferomedial blowout fracture remains a challenge to orbital surgeon. The authors restored the fracture using combined transnasal and transorbital approaches using support of both paranasal sinuses. The authors compared surgical results of this novel method with those of the traditional procedure. Of 106 inferomedial blowout fracture patients who underwent surgical treatment between March 2007 and July 2013, 50 patients were selected in our study: 25 patients underwent the traditional procedure as controls, and the other 25 patients underwent orbital wall restoring surgery by our combined approach. Outcomes were evaluated in terms of the orbital volume ratio (OVR) and changes in Hertel scale. The OVR in the experimental group (7.19%) decreased more significantly than in the control group (2.71%) (P < 0.05). In conclusion, the orbit was restored more successfully following orbital wall restoring surgery with dual support than by using the traditional inferomedial blowout fracture procedure.

3D Printing of Collagen Scaffold with Enhanced Resolution in a Citrate-Modulated Gellan Gum Microgel Bath.

3D printing in a microgel-based supporting bath enables the construction of complex structures with soft and watery biomaterials but the low print resolution is usually an obstacle to its practical application in tissue engineering. Herein, high-resolution printing of a 3D collagen organ scaffold is realized by using an engineered Gellan gum (GG) microgel bath containing trisodium citrate (TSC). The introduction of TSC into the bath system not only mitigates the aggregation of GG microgels, leading to a more homogeneous bath morphology but also suppresses the diffusion of the collagen ink in the bath due to the dehydration effect of TSC, both of which contribute to the improvement of print resolution. 3D collagen organ structures such as hand, ear, and heart are successfully constructed with high shape fidelity in the developed bath. After printing, the GG and TSC can be easily removed by washing with water, and the obtained collagen product exhibits good cell affinity in a tissue scaffold application. This work offers an easy-to-operate strategy for developing a microgel bath for high-resolution printing of collagen, providing an alternative path to in vitro 3D organ construction.

Retromandibular reduction of medially dislocated condylar process fractures.

BACKGROUND: Condylar process fractures account for one-third of all mandibular fractures, and the distal fragment is prone to dislocate to the medial side due to the pulling of the lateral pterygoid muscle. Retromandibular approaches are commonly used, but the intraoperative view becomes limited in medially dislocated fractures. This study summarized a series of cases of retromandibular reduction for medially dislocated condylar process fractures and described our supplementary procedure to realign the dislocated condylar process. METHODS: Nine patients with medially dislocated condylar process fractures underwent surgical correction from January 2012 to December 2016. In 6 of them, it was possible to realign the fractures with a conventional retromandibular approach, but for 3 cases of severe dislocation to the middle cranial fossa, a supplementary transoral procedure was carried out. The angle difference between the ramus and condyle, ramus height, and maximal mouth opening (MMO) were evaluated. RESULTS: All 9 cases were restored to the proper anatomical alignment without any major complications, and postoperative images revealed successful union. The angle difference was 8.94°±4.11° preoperatively, and 0.99±0.49° at the 6-month follow-up. The pretreatment ramus height difference was 6.12±6.09 mm, and the postoperative difference was 0.18±0.10 mm. These changes after surgery were statistically significant. The MMO before surgery was 11.44±3.0 mm, and the postoperative MMO was 37.2±2.9 mm, reflecting a significant increase after reduction. CONCLUSIONS: Retromandibular reduction is a useful method in medially dislocated condylar process fractures, and additional transoral assistance should be considered to realign condylar processes that severely dislocate to the middle cranial fossa.

Orthodromic transfer of the temporalis muscle in incomplete facial nerve palsy.

BACKGROUND: Temporalis muscle transfer produces prompt surgical results with a one-stage operation in facial palsy patients. The orthodromic method is surgically simple, and the vector of muscle action is similar to the temporalis muscle action direction. This article describes transferring temporalis muscle insertion to reconstruct incomplete facial nerve palsy patients. METHODS: Between August 2009 and November 2011, 6 unilateral incomplete facial nerve palsy patients underwent surgery for orthodromic temporalis muscle transfer. A preauricular incision was performed to expose the mandibular coronoid process. Using a saw, the coronoid process was transected. Three strips of the fascia lata were anchored to the muscle of the nasolabial fold through subcutaneous tunneling. The tension of the strips was adjusted by observing the shape of the nasolabial fold. When optimal tension was achieved, the temporalis muscle was sutured to the strips. The surgical results were assessed by comparing pre- and postoperative photographs. Three independent observers evaluated the photographs. RESULTS: The symmetry of the mouth corner was improved in the resting state, and movement of the oral commissure was enhanced in facial animation after surgery. CONCLUSIONS: The orthodromic transfer of temporalis muscle technique can produce prompt results by applying the natural temporalis muscle vector. This technique preserves residual facial nerve function in incomplete facial nerve palsy patients and produces satisfying cosmetic outcomes without malar muscle bulging, which often occurs in the turn-over technique.

Surgical management of a mandible subcondylar fracture.

Open reduction and anatomic reduction can create better function for the temporomandibular joint, compared with closed treatment in mandible fracture surgery. Therefore, the double miniplate fixation technique via mini-retromandibular incision was used in order to make the most stable fixation when performing subcondylar fracture surgery. Those approaches provide good visualization of the subcondyle from the posterior edge of the ramus, allow the surgeon to work perpendicularly to the fracture, and enable direct fracture management. Understanding the biomechanical load in the fixation of subcondylar fractures is also necessary in order to optimize fixation methods. Therefore, we measured the biomechanical loads of four different plate fixation techniques in the experimental model regarding mandibular subcondylar fractures. It was found that the loads measured in the two-plate fixation group with one dynamic compression plate (DCP) and one adaption plate showed the highest deformation and failure loads among the four fixation groups. The loads measured in the one DCP plate fixation group showed higher deformation and failure loads than the loads measured in the two adaption plate fixation group. Therefore, we conclude that the selection of the high profile plate (DCP) is also important in order to create a stable load in the subcondylar fracture.

Analysis of incidences and types of complications in mandibular angle ostectomy in Koreans.

A prominent mandibular angle is considered to be unattractive in Asians because it gives the face a square, coarse, and muscular appearance. Asian women desire to have an ovoid, reduced, and slender face by aesthetic mandibular angle resection. Mandibular angle ostectomy has been known to be effective and to satisfy both surgeons and patients. Especially in Korea, it has become as popular as facial bone contouring surgery, which reduces lower facial width. However, a narrow surgical field hinders direct view of the site, making a procedure that is rather difficult to perform. Despite thorough presurgical planning and attention, there can be many complications and unfavorable results. The purpose of this study is to find out the cause of these complications of mandibular angle ostectomy and to develop methods that could prevent these complications from occurring. A questionnaire consisting of 30 questions regarding mandibular angle ostectomy was sent to 40 Korean plastic surgeons. Data from 33 surgeons were analyzed. The total number of operations was 1251, and among them complications appeared in 124 operations, a complication rate of 9.9%. In regards to severe complications, there were 8 cases of subcondyle fracture of the mandible and 6 cases of severe bleeding. Transient facial nerve injury, infection, trismus, asymmetry, undercorrection, overcorrection, secondary angle formation, and entrapped bony segment were also noted as complications. We will report the cause and the prevention methods for each complication.