Is mesh fixation necessary in laparoendoscopic techniques for M3 inguinal defects? An experimental study.

BACKGROUND: Although international guidelines recommend not fixing the mesh in almost all cases of laparoendoscopic repairs, in case of large direct hernias (M3) mesh fixation is recommended to reduce recurrence risk. Despite lack of high-quality evidence, the recommendation was upgraded to strong by expert panel. The authors conducted a research experiment to verify the hypothesis that it is possible to preserve the mesh in the operating field in large direct hernias (M3) without the need to use fixing materials. METHOD: The authors conducted an experiment with scientists from Universities of Technology in a model that reflects the conditions in the groin area. By simulating conditions of the highest possible intra-abdominal pressure, they examined the mesh behavior within the groin and its ability to dislocate under the forces generated by this pressure. The experiment involved six spatial implants and one flat macroporous mesh. RESULTS: Heavyweight spatial meshes and lightweight spatial-individualized meshes showed no tendency to dislocate or move directly to the orifice, which was considered a rapid hernia recurrence. Lightweight meshes, both spatial and flat, underwent significant migration and shifting toward the hernial orifices. CONCLUSION: Based on the results, we believe that mesh fixation is not the only alternative to preventing recurrence in complex defects. Similar effects can be achieved using a larger, more rigid, and anatomically fitted implant. The type of implant (rather than its fixation) seems to be a key factor from the point of view of mechanics and biophysics. Clinical trials confirming the results in vivo will allow to supplement or amend the guidelines for the treatment of large inguinal hernias.

Development and Implantation of 3D Anatomically Tailored Polypropylene Mesh for Laparoscopic Inguinal Hernia Repair Designed on the Basis of CT Images (the ILAM Study).

OBJECTIVE: The aim of the ILAM (Individualized Laparoscopic Anatomical Mesh) study was to create and implant a fully individualized mesh based on CT scans, taking into account the published body of knowledge about the material and mechanical behavior of the implant for laparoscopic inguinal hernia repair. SUMMARY BACKGROUND DATA: The team creating and conducting this study consisted of surgeons and engineers. A specific project was made and divided into 4 phases. METHODS: The process of development and implantation was divided into 4 milestones: CT scans and modeling based on predefined subgroups, mesh manufacture, certification and clinical evaluation. RESULTS: The result of the study was the first individually designed hernia mesh to have been implanted in a human subject. After 12 months of follow-up, no recurrences or other complications were reported. CONCLUSIONS: The new mesh provides a better anatomic fit to the patients' inguinal region geometry. Mechanical stability is ensured by the multiple contact points between the implant and the tissues, which generate friction forces. Together with the possibility of shape design (proper overlap), the authors believe that there is no need for mesh fixation. If so, the use of such design meshes can change the guidelines in laparoendoscopic hernia repair in the future.

The influence of flowmeters on rhinomanometry results and detection of nasal airflow asymmetry.

<b><br>Introduction:</b> Rhinomanometry is an otolaryngological diagnostic method used to determine airflow as a function of the pressure drop through the left and right nasal cavities. Airflow is measured using orifice flowmeters that attenuate the flow.</br> <b><br>Aim:</b> This paper describes the results of a study into the effects of flowmeter design on rhinomanometry results and detection of nasal airflow asymmetry.</br> <b><br>Material and methods:</b> Four flowmeters were examined using a 3D printed model of a human nose.</br> <b><br>Conclusions:</b> Each flowmeter interfered with the rhinomanometry results.</br>.

Cranioplasty prosthesis manufacturing based on reverse engineering technology.

BACKGROUND: Most patients with large focal skull bone loss after craniectomy are referred for cranioplasty. Reverse engineering is a technology which creates a computer-aided design (CAD) model of a real structure. Rapid prototyping is a technology which produces physical objects from virtual CAD models. The aim of this study was to assess the clinical usefulness of these technologies in cranioplasty prosthesis manufacturing. MATERIAL/METHODS: CT was performed on 19 patients with focal skull bone loss after craniectomy, using a dedicated protocol. A material model of skull deficit was produced using computer numerical control (CNC) milling, and individually pre-operatively adjusted polypropylene-polyester prosthesis was prepared. In a control group of 20 patients a prosthesis was manually adjusted to each patient by a neurosurgeon during surgery, without using CT-based reverse engineering/rapid prototyping. In each case, the prosthesis was implanted into the patient. The mean operating times in both groups were compared. RESULTS: In the group of patients with reverse engineering/rapid prototyping-based cranioplasty, the mean operating time was shorter (120.3 min) compared to that in the control group (136.5 min). The neurosurgeons found the new technology particularly useful in more complicated bone deficits with different curvatures in various planes. CONCLUSIONS: Reverse engineering and rapid prototyping may reduce the time needed for cranioplasty neurosurgery and improve the prosthesis fitting. Such technologies may utilize data obtained by commonly used spiral CT scanners. The manufacturing of individually adjusted prostheses should be commonly used in patients planned for cranioplasty with synthetic material.

Virtual rhinomanometry based on computed tomography of the paranasal sinuses in patients with nasal septum deviation a pilot study.

AIM: The aim of the study was to compare the flow disturbances in computational fluid dynamics (CFD) technique based on computed tomography (CT) to the results of active anterior rhinomanometry (RMM), in patients with nasal septum deviation (NSD). MATERIAL AND METHODS: In 24 patients with NSD, RMM and CT of the paranasal sinuses were performed as a part of typical clinical management. For each patient, 3D models of air-filled spaces in the nasal cavity were created, based on CT images, and air flow simulations during inhalation were performed using CFD technique. Correlations between RMM, both before and after anemization, during inspiration, and CFD were tested, independently for the left and right side. RESULTS: The obtained correlation coefficients for the comparison of flow in RMM during inspiration and in CFD during simulated inspiration were: before anemization 0.46 for the left side and 0.52 for the right side, after anemization 0.65 for the left side and 0.61 for the right side (p < 0.05). CONCLUSIONS: Moderate correlation was found between the results of real and virtual rhinomanometry, with higher correlation coefficients obtained after anemization, compared to the values before anemization.