Fabrication of 3D Printed poly(lactic acid) strut and wet-electrospun cellulose nano fiber reinforced chitosan-collagen hydrogel composite scaffolds for meniscus tissue engineering.

The main goal of the study was to produce chitosan-collagen hydrogel composite scaffolds consisting of 3D printed poly(lactic acid) (PLA) strut and nanofibrous cellulose for meniscus cartilage tissue engineering. For this purpose, first PLA strut containing microchannels was incorporated into cellulose nanofibers and then they were embedded into chitosan-collagen matrix to obtain micro- and nano-sized topographical features for better cellular activities as well as mechanical properties. All the hydrogel composite scaffolds produced by using three different concentrations of genipin (0.1, 0.3, and 0.5%) had an interconnected microporous structure with a swelling ratio of about 400% and water content values between 77 and 83% which is similar to native cartilage extracellular matrix. The compressive strength of all the hydrogel composite scaffolds was found to be similar (∼32 kPa) and suitable for cartilage tissue engineering applications. Besides, the hydrogel composite scaffold comprising 0.3% (w/v) genipin had the highest tan δ value (0.044) at a frequency of 1 Hz which is around the walking frequency of a person. According to the in vitro analysis, this hydrogel composite scaffold did not show any cytotoxic effect on the rabbit mesenchymal stem cells and enabled cells to attach, proliferate and also migrate through the inner area of the scaffold. In conclusion, the produced hydrogel composite scaffold holds great promise for meniscus tissue engineering.

Three-Dimensional Printing Assisted Preoperative Surgical Planning for Cerebral Arteriovenous Malformation

Objective@#: The aim of this study to investigate the benefits of patient-based 3-dimensional (3D) cerebral arteriovenous malformation (AVM) models for preoperative surgical planning and education. @*Methods@#: Fifteen patients were operated on for AVMs between 2015 and 2019 with patient-based 3D models. Ten patients’ preoperative cranial angiogram screenings were evaluated preoperatively or perioperatively via patient-based 3D models. Two patients needed emergent surgical intervention; their models were solely designed based on their AVMs and used during the operation. However, the other patients who underwent elective surgery had the modeling starting from the skull base. These models were used both preoperatively and perioperatively. The benefits of patients arising from treatment with these models were evaluated via patient files and radiological data. @*Results@#: Fifteen patients (10 males and five females) between 16 and 66 years underwent surgery. The mean age of the patients was 40.0±14.72. The most frequent symptom patients observed were headaches. Four patients had intracranial bleeding; the symptom of admission was a loss of consciousness. Two patients (13.3%) belonged to Spetzler-Martin (SM) grade I, four (26.7%) belonged to SM grade II, eight (53.3%) belonged to SM grade III, and one (6.7%) belonged to SM grade IV. The mean operation duration was 3.44±0.47 hours. Three patients (20%) developed transient neurologic deficits postoperatively, whereas three other patients died (20%). @*Conclusion@#: Several technological innovations have emerged in recent years to reduce undesired outcomes and support the surgical team. For example, 3D models have been employed in various surgical procedures in the last decade. The routine usage of patient-based 3D models will not only support better surgical planning and practice, but it will also be useful in educating assistants and explaining the situation to the patient as well.

Scapular spine base fracture with long outside-in superior or posterior screws with reverse shoulder arthroplasty

Background@#The purpose of the present study was to determine how long superior screws alone or in combination with posterior placement of metaglene screws protruding and penetrating into the scapular spine in reverse total shoulder arthroplasty affect the strength of thescapular spine in a fresh cadaveric scapular model. @*Methods@#Seven fresh cadaver scapulas were allocated to the control group (short posterior and superior screws) and seven scapulars to thestudy group (spine base fixation with a four long screws, three with both long superior and long posterior screws). @*Results@#The failure load was lower in the spine fixation group (long screw, 869 N vs. short screw, 1,123 N); however, this difference did notreach statistical significance (p>0.05). All outside-in long superior or superior plus posterior screws failed due to scapular spine base fracture; failures in the short screw group were due to acromion fracture. An additional posterior outside-in screw failed to significantly decrease the failure load of the acromion spine. @*Conclusions@#The present study highlights the significance of preventing a cortical breach or an outside-in configuration when a superioror posterior screw is inserted into the scapular spine base.

Scapular spine base fracture with long outside-in superior or posterior screws with reverse shoulder arthroplasty

Background@#The purpose of the present study was to determine how long superior screws alone or in combination with posterior placement of metaglene screws protruding and penetrating into the scapular spine in reverse total shoulder arthroplasty affect the strength of thescapular spine in a fresh cadaveric scapular model. @*Methods@#Seven fresh cadaver scapulas were allocated to the control group (short posterior and superior screws) and seven scapulars to thestudy group (spine base fixation with a four long screws, three with both long superior and long posterior screws). @*Results@#The failure load was lower in the spine fixation group (long screw, 869 N vs. short screw, 1,123 N); however, this difference did notreach statistical significance (p>0.05). All outside-in long superior or superior plus posterior screws failed due to scapular spine base fracture; failures in the short screw group were due to acromion fracture. An additional posterior outside-in screw failed to significantly decrease the failure load of the acromion spine. @*Conclusions@#The present study highlights the significance of preventing a cortical breach or an outside-in configuration when a superioror posterior screw is inserted into the scapular spine base.

Comparison of Biomechanical Properties of Dura Mater Substitutes and Cranial Human Dura Mater : An In Vitro Study

OBJECTIVE: The aim of this study was to investigate the biomechanical differences between human dura mater and dura mater substitutes to optimize biomimetic materials.METHODS: Four groups were investigated. Group I used cranial dura mater (n=10), group II used Gore-Tex® Expanded Cardiovascular Patch (W.L. Gore & Associates Inc., Flagstaff, AZ, USA) (n=6), group III used Durepair® (Medtronic Inc., Goleta, CA, USA) (n=6), and group IV used Tutopatch® (Tutogen Medical GmbH, Neunkirchen am Brand, Germany) (n=6). We used an axial compression machine to measure maximum tensile strength.RESULTS: The mean tensile strengths were 7.01±0.77 MPa for group I, 22.03±0.60 MPa for group II, 19.59±0.65 MPa for group III, and 3.51±0.63 MPa for group IV. The materials in groups II and III were stronger than those in group I. However, the materials in group IV were weaker than those in group I.CONCLUSION: An important dura mater graft property is biomechanical similarity to cranial human dura mater. This biomechanical study contributed to the future development of artificial dura mater substitutes with biomechanical properties similar to those of human dura mater.

Biomechanical Properties of the Cranial Dura Mater with Puncture Defects: An In Vitro Study

OBJECTIVE: The primary aim of this investigation was to explore the nature of dura mater biomechanics following the introduction of puncture defect(s).METHODS: Twenty-eight dura mater specimens were collected during autopsy from the department of forensic medicine of the authors' institution. Specimens were divided randomly into one of four groups : group I (cranial dura mater; n=7), group II (cranial dura mater with one puncture defect; n=7); group III (cranial dura mater with two puncture defects; n=7), and group IV (cranial dura mater with three puncture defects; n=7).RESULTS: The mean±standard deviation tensile strengths of the dura mater were 8.35±3.16, 8.22±3.32, 7.13±1.77, and 6.94±1.93 MPa for groups I, II, III, and IV, respectively. There was no statistical difference between all groups. A single, two or more punctures of the dura mater using a 20-gauge Quincke needle did not affect cranial dura tensile strength.CONCLUSION: This biomechanical study may contribute to the future development of artificial dura mater substitutes and medical needles that have a lower negative impact on the biomechanical properties of dura mater.

Comparison of Biomechanical Properties of Dura Mater Substitutes and Cranial Human Dura Mater : An In Vitro Study

OBJECTIVE: The aim of this study was to investigate the biomechanical differences between human dura mater and dura mater substitutes to optimize biomimetic materials. METHODS: Four groups were investigated. Group I used cranial dura mater (n=10), group II used Gore-Tex® Expanded Cardiovascular Patch (W.L. Gore & Associates Inc., Flagstaff, AZ, USA) (n=6), group III used Durepair® (Medtronic Inc., Goleta, CA, USA) (n=6), and group IV used Tutopatch® (Tutogen Medical GmbH, Neunkirchen am Brand, Germany) (n=6). We used an axial compression machine to measure maximum tensile strength. RESULTS: The mean tensile strengths were 7.01±0.77 MPa for group I, 22.03±0.60 MPa for group II, 19.59±0.65 MPa for group III, and 3.51±0.63 MPa for group IV. The materials in groups II and III were stronger than those in group I. However, the materials in group IV were weaker than those in group I. CONCLUSION: An important dura mater graft property is biomechanical similarity to cranial human dura mater. This biomechanical study contributed to the future development of artificial dura mater substitutes with biomechanical properties similar to those of human dura mater.

Biomechanical Properties of the Cranial Dura Mater with Puncture Defects: An In Vitro Study

OBJECTIVE: The primary aim of this investigation was to explore the nature of dura mater biomechanics following the introduction of puncture defect(s). METHODS: Twenty-eight dura mater specimens were collected during autopsy from the department of forensic medicine of the authors' institution. Specimens were divided randomly into one of four groups : group I (cranial dura mater; n=7), group II (cranial dura mater with one puncture defect; n=7); group III (cranial dura mater with two puncture defects; n=7), and group IV (cranial dura mater with three puncture defects; n=7). RESULTS: The mean±standard deviation tensile strengths of the dura mater were 8.35±3.16, 8.22±3.32, 7.13±1.77, and 6.94±1.93 MPa for groups I, II, III, and IV, respectively. There was no statistical difference between all groups. A single, two or more punctures of the dura mater using a 20-gauge Quincke needle did not affect cranial dura tensile strength. CONCLUSION: This biomechanical study may contribute to the future development of artificial dura mater substitutes and medical needles that have a lower negative impact on the biomechanical properties of dura mater.