Replacing cutting guides with an augmented reality-based navigation system: A feasibility study in the maxillofacial region.

PURPOSE: The work presents outcomes of simulated maxillofacial skeleton osteotomies supported with cutting guides or one of two AR-based intraoperative navigation systems. MATERIAL AND METHODS: The series of osteotomies supported with a cutting guide, simple AR (sAR) or navigated AR (nAR) module were carried out on 15 (five per each method) skull models according to the virtual surgical plan (VSP). Each method was used to support 40 osteotomies involving the upper jaw and 40 involving the orbital region (16 osteotomies on each model). Postoperative computed tomography scans were fused with the VSP to analyse angular deviations from the planned cutting trajectory (°) and the deviations of labelled control points (mm). RESULTS: Guides provided the highest accuracy, with a mean osteotomy angular deviation of 3.73 ± 2.94° and a mean control point deviation of 1.30 ± 0.73 mm. Mean angular deviations for the sAR- and nAR-assisted osteotomies were 5.93 ± 5.12° and 6.75 ± 5.33°, and mean control point deviations amounted to 1.86 ± 0.88 mm and 1.97 ± 0.70 mm.

Biodegradable Fiducial Markers for Bimodal Near-Infrared Fluorescence- and X-ray-Based Imaging.

This study aimed to evaluate, for the first time, implantable, biodegradable fiducial markers (FMs), which were designed for bimodal, near-infrared fluorescence-based (NIRF) and X-ray-based imaging. The developed FMs had poly(l-lactide-co-caprolactone)-based core-shell structures made of radiopaque (core) and fluorescent (shell) composites with a poly(l-lactide-co-caprolactone) matrix. The approved for human use contrast agents were utilized as fillers. Indocyanine green was applied to the shell material, whereas in the core materials, iohexol and barium sulfate were compared. Moreover, the possibility of tailoring the stability of the properties of the core materials by the addition of hydroxyapatite (HAp) was examined. The performed in situ (porcine tissue) and in vivo experiment (rat model) confirmed that the developed FMs possessed pronounced contrasting properties in NIRF and X-ray imaging. The presence of HAp improved the radiopacity of FMs at the initial state. It was also proved that, in iohexol-containing FMs, the presence of HAp slightly decreased the stability of contrasting properties, while in BaSO4-containing ones, changes were less pronounced. A comprehensive material analysis explaining the differences in the stability of the contrasting properties was also presented. The tissue response around the FMs with composite cores was comparable to that of the FMs with a pristine polymeric core. The developed composite FMs did not cause serious adverse effects on the surrounding tissues even when irradiated in vivo. The developed FMs ensured good visibility for NIRF image-supported tumor surgery and the following X-ray image-guided radiotherapy. Moreover, this study replenishes a scanty report regarding similar biodegradable composite materials with a high potential for application.

The Use of Adipose-Derived Stem Cells (ADSCs) and Stromal Vascular Fraction (SVF) in Skin Scar Treatment-A Systematic Review of Clinical Studies.

In recent years, lipofilling became a popular scar treatment method. Its beneficial outcomes have been partly attributed to the regenerative capacity of adipose-derived stem cells (ADSCs), suspended in an extracellular matrix-the stromal vascular fraction (SVF). The aim of this review was to verify if existing data support the clinical use of ADSC-related interventions in scar treatment. A systematic search of the literature was performed in July 2020 in five databases (Medline, Cochrane, Web of Science, Scopus and Embase). Articles written in English, except for reviews, letters and editorials, were identified and screened for eligibility. We looked for reports of any outcomes in scars treated with ADSCs or SVF. Data from selected articles were extracted and the quality of each study was assessed. Five hundred and fourteen studies were identified in the primary search, of which nineteen were eventually included in the systematic review. Extracted data pointed to beneficial microscopic, functional and aesthetic outcomes in a total of 665 patients. Six studies included comparative interventions-platelet-rich plasma or CO2 fractional laser. Collected data give low-to-average quality evidence for beneficial effects of ADSC-related interventions in scar treatment. Some studies suggest that these interventions are noninferior to PRP or fractional CO2 laser.

The Impact of Mastectomy on Women's Visual Perception of Breast Aesthetics and Symmetry: A Pilot Eye-Tracking Study.

BACKGROUND: Little is known about breast cancer survivors' perception of breast attractiveness. A better understanding of this subjective concept could contribute to the improvement of patient-reported outcomes after reconstructive surgeries and facilitate the development of new methods for assessing breast reconstruction outcomes. OBJECTIVES: The aim of this eye-tracking (ET)-based study was to verify whether mastectomy altered women's visual perception of breast aesthetics and symmetry. METHODS: A group of 30 women after unilateral mastectomy and 30 healthy controls evaluated the aesthetics and symmetry of various types of female breasts displayed as highly standardized digital images. Gaze patterns of women from the study groups were recorded using an ET system and subjected to a comparative analysis. RESULTS: Regardless of the study group, the longest fixation duration and the highest fixation number were found in the nipple-areola complex. This area was also the most common region of the initial fixation. Several significant between-group differences were identified; the gaze patterns of women after mastectomy were generally characterized by longer fixation times for the inframammary fold, lower pole, and upper half of the breast. CONCLUSIONS: Mastectomy might affect women's visual perception patterns during the evaluation of breast aesthetics and symmetry. ET data might improve our understanding of breast attractiveness and constitute the basis for a new reliable method for the evaluation of outcomes of reconstructive breast surgeries.

Supporting fibula free flap harvest with augmented reality: A proof-of-concept study.

OBJECTIVE: To analyze a novel navigation system utilizing augmented reality (AR) as a supporting method for fibula free flap (FFF) harvest and fabrication. METHODS: A total of 126 simulated osteotomies supported with a cutting guide or one of two AR-based intraoperative navigation modules-simple AR (sAR) or navigated AR (nAR)-were carried out on 18 identical models of the fibula (42 osteotomies per method). After fusing postoperative computed tomography scans of the operated fibulas with the virtual surgical plan based on preoperative images, the objective outcomes-angular deviations from the planned osteotomy trajectory (o ) and deviations of control points marked on the trajectory (mm)-were determined. RESULTS: All analyzed methods provided similar accuracy of assisted osteotomies. The only significant difference referred to angular deviation in the sagittal plane, which was smaller after the cutting guide-assisted procedures than after the application of sAR and nAR (4.1 ± 2.29 vs. 5.08 ± 3.64 degrees, P = 0.031 and 4.1 ± 2.29 vs. 4.97 ± 2.91, P = 0.002, respectively). Mean deviation of control points after the cutting guide-assisted procedures was 2.76 ± 1.06 mm, as compared with 2.67 ± 1.09 mm for sAR and 2.95 ± 1.11 mm for nAR. CONCLUSION: Our study demonstrated that both novel AR-based methods provided similar accuracy of assisted harvesting and contouring of the FFF as the cutting guides. This fact, as well as the acceptability of the concept by clinicians, justify their further development and evaluation in preclinical settings. LEVEL OF EVIDENCE: NA Laryngoscope, 130:1173-1179, 2020.

Increased temperature-related adeno-associated virus vectors transduction of ovarian cancer cells - essential signatures of AAV receptor and heat shock proteins.

Recombinant adeno-associated viruses (rAAVs) are becoming more commonly used in clinical trials involving gene therapy. Additionally AAV-based drugs have already been registered. Gene therapy aims to increase transduction efficiency, increase in vivo selectivity and reduce side effects. One approach to achieve this is the use of physical factors, such as temperature or more specifically, hyperthermia, which is already utilized in oncology. The aim of the present study was to investigate the effect of hyperthermic conditions (40°C and 43°C) on the rAAV transduction efficiency of ovarian cancer cells (Caov-3 and NIH:OVCAR-3) and non-cancerous cells (AAV-293). The present study was designed to identify functional associations between the level of gene transfer and the expression of representative genes for rAAV transmission (AAVR (AAV receptor), heparan sulfate proteoglycan (HSPG) 1 and HSPG2) and heat shock proteins (HSPs). The expressions of selected genes were measured via reverse transcription-quantitative PCR and cell adhesion/invasion chamber tests were also performed. The results revealed that ovarian cancer cell lines were more efficiently transduced with rAAV vectors at an elevated temperature. Additionally, the expression patterns of AAVR, HSPG1 and HSPG2 genes were different between the tested lines. The expression of certain receptors in ascites-derived NIH:OVCAR-3 ovarian cancer cells was higher compared with tumor-derived Caov-3 cells at 37, 40 and 43°C, which indicates a higher transduction efficiency in the formerly mentioned cells. Ascites-derived ovarian cancer cells were characterized by high expressions of HSP40, HSP90 and HSP70 families. Lower levels of HSP expression were demonstrated in less-effectively transduced Caov-3 cells. Furthermore, expressions of the examined genes changed with increasing temperature. The results indicated that temperature-dependent transduction is associated with the expression of the rAAV receptor and HSP genes. The results of the current study may aid the design of effective protocols for ovarian cancer gene therapy.

Analysis of the Visual Perception of Female Breast Aesthetics and Symmetry: An Eye-Tracking Study.

BACKGROUND: Because of its subjective character, the term "breast attractiveness" is poorly defined and thus its reliable standardized assessment can be particularly challenging. Because of objective analysis of the observer's gaze pattern, eye-tracking technology may provide a better insight into the visual perception of breast aesthetics and symmetry. METHODS: One hundred observers, 50 women and 50 men, assessed the aesthetics and symmetry of eight types of female breasts displayed as digital images on frontal, lateral, and oblique projections. The gaze pattern of each observer was recorded using eye-tracking technology, and gaze data were subsequently analyzed. RESULTS: Although sex and breast type exerted an effect on attention capturing by some areas of interest, key characteristics of gaze patterns in female and male observers were essentially the same. Irrespective of observers' sex, the longest fixation duration and the highest fixation number were recorded for lower breast regions, in particular, for the nipple-areola complex. Mean fixation duration in this area corresponded to 58 and 57 percent of overall observation time for female and male observers, respectively, during the assessment of breast aesthetics; and to 56 and 52 percent of overall observation time for female and male observers, respectively, during the assessment of breast symmetry. CONCLUSIONS: Nipple-areola complex and lower breast are key focus areas for the assessment of breast aesthetics and symmetry. Gaze data collected during this study may constitute a valuable source of reference values for future eye-tracking research on various patient groups' visual perception of breast attractiveness and deformities.

Supporting mandibular resection with intraoperative navigation utilizing augmented reality technology - A proof of concept study.

OBJECTIVE: The aim of this study was to compare the accuracy of simulated mandibular osteotomies performed with cutting guides and two different intraoperative navigation systems based on simple (sAR) and navigated (nAR) augmented reality technology. MATERIAL AND METHODS: A total of 126 osteotomies were performed on 21 identical mandible models according to a prespecified virtual surgery plan. The data from postoperative computed tomography (CT) images were fused with preoperative CT scans to objectively compare the outcomes, i.e. angular deviations from the osteotomy trajectory (°) and displacement of two control points (mm). RESULTS: Osteotomies performed with cutting guides turned out to be the most accurate, with mean angular deviation of 4.94 ± 4.62° and mean control point displacement of 1.65 ± 0.88 mm. Mandibular osteotomies assisted with sAR and nAR were less accurate in terms of mean angular deviations (5.34 ± 3.67° and 7.14 ± 5.19°, respectively) and control point displacements (1.79 ± 0.94 mm and 2.41 ± 1.34 mm, respectively). CONCLUSION: Our findings imply that in future, AR-based intraoperative navigation systems may find application in everyday clinical practice. Although AR technology still requires some improvements, it can already be used for presentation of digital navigation data, enhancing surgeon's awareness and hand-eye coordination during mandibular resection and reconstruction procedures.

Navigation-guided fibula free flap for mandibular reconstruction: A proof of concept study.

OBJECTIVE: To analyze a novel technique of supporting fibula free flap harvest and fabrication with intraoperative navigation technology. MATERIALS AND METHODS: In the first phase of the study, navigation accuracy achieved with two registration methods, namely, point-pair and hybrid technique utilizing point-pair with surface matching, were evaluated in the form of the fiducial (FRE) and target registration error (TRE). Next, a series of 42 simulated navigated fibular osteotomies were conducted on specially manufactured lower leg phantom. Postoperative results were analyzed in the form of the angular and position deviations between the virtually planned and the obtained osteotomies. RESULTS: Mean FRE values obtained with point-pair and hybrid registration methods were 1.82 ± 0.96 mm and 1.41 ± 0.44 mm, respectively. Mean TRE value in the fibula region was 2.00 ± 0.67 mm for the first method and 1.51 ± 0.72 mm for the second. For all performed surgeries, the total mean angular deviation between the planned and actual osteotomy trajectory equaled 3.66° ± 3.60°. The total mean position disparity of osteotomy control points was 1.85 ± 0.99 mm. CONCLUSIONS: Navigation-guided free fibula flap harvest and fabrication, due to encouraging study results and its superiority over currently popular cutting guides in many clinical aspects, may become a routine operative procedure for the reconstruction of complex mandibular defects. The presented method is especially well suited for plastic and maxillofacial surgery.

Aspects of Modern Biobank Activity - Comprehensive Review.

Biobanks play an increasing role in contemporary research projects. These units meet all requirements to regard them as a one of the most innovative and up-to-date in the field of biomedical research. They enable conducting wide-scale research by the professional collection of biological specimens and correlated clinical data. Pathology units may be perceived roots of biobanking. The review aims at describing the concept of biobanks, their model of function and scientific potential. It comprises the division of biobanks, sample preservation methods and IT solutions as well as guidelines and recommendations for management of a vast number of biological samples and clinical data. Therefore, appropriate standard operating procedures and protocols are outlined. Constant individualization of diagnostic process and treatment procedures creates the niche for translational units. Thus, the role of biobanks in personalized medicine was also specified. The exceptionality of biobanks poses some new ethical-legal issues which have various solutions, in each legal system, amongst the world. Finally, distribution and activity of European biobanks are mentioned.

Image-guided bone resection as a prospective alternative to cutting templates­A preliminary study.

OBJECTIVE: To evaluate the accuracy of craniomaxillofacial resections performed with an image-guided surgical sagittal saw. MATERIAL AND METHODS: Twenty-four craniomaxillofacial resections were performed using an image-guided sagittal saw. Surgical outcomes were compared with a preoperative virtual plan in terms of the resected bone volume, control point position and osteotomy trajectory angle. Each measurement was performed twice by two independent observers. RESULTS: The best convergence between the planned and actual bone resection was observed for the orbital region (6.33 ± 4.04%). The smallest mean difference between the preoperative and postoperative control point positions (2.00 ± 0.66 mm) and the lowest mean angular deviation between the virtual and actual osteotomy (5.49 ± 3.17 degrees) were documented for the maxillary region. When all the performed procedures were analyzed together, mean difference between the planned and actual bone resection volumes was 9.48 ± 4.91%, mean difference between the preoperative and postoperative control point positions amounted to 2.59 ± 1.41 mm, and mean angular deviation between the planned and actual osteotomy trajectory equaled 8.21 ± 5.69 degrees. CONCLUSION: The results of this study are encouraging but not fully satisfactory. If further improved, the hereby presented navigation technique may become a valuable supporting method for craniomaxillofacial resections.

Leiomyosarcoma of the external ear--case report.

In head and neck region leiomyosarcoma is a very rare finding. This tumor is usually located in abdominal cavity. We report a case of 78-year-old man with tumor of the auricle that was resected with 0.7 cm margin. Histological and immunohistochemical analysis revealed the leiomyosarcoma. Adjuvant therapy was not advised. During 3 years of follow-up there are no signs of recurrence. Review of the literature shows that the survival of patients with leiomyosarcoma in head and neck region seems to be similar to other kinds of sarcomas in this localization. It is not clear, how large surgical margins should be to achieve satisfactory local control.

Contamination of the surgical field in head and neck oncologic surgery.

BACKGROUND: The purpose of this study was to determine the timing and type of surgical field contamination in 50 consecutive resections for advanced head and neck cancer with same-stage tissue reconstruction and to analyze the relationship between contamination and the surgical site infection. METHODS: Swabs from the surgical field and from surgical drapes close to the field were taken every 2 hours (at 0 hour, 2 hours, 4 hours, and 6 hours) and sent for a standard microbiological diagnostic procedure. Results were recorded in Microsoft Excel and analyzed with SPSS. RESULTS: We collected 336 swabs of which 71% were contaminated. Polymicrobial contamination was observed in 153 samples (45%). Twenty-six species of pathogens were found, the most frequent was Streptococcus species. Surgical site infection with positive culture occurred in 3 patients. CONCLUSION: In head and neck surgery for advanced cancer, standard aseptic procedures do not prevent contamination of the surgical field with physiological bacterial flora of the skin and oral cavity. Although contamination was common, surgical site infection was rare.

[Microsurgical fasciocutaneous and musculocutaneous free flaps in head and neck surgery]. / Zastosowanie mikronaczyniowych wolnych platów powieziowo-skórnych i miesniowo-skórnych w chirurgii glowy i szyi.

OBJECTIVES: Reconstruction of the head and neck continues to pose a significant challenge for reconstructive surgeons. In many cases microsurgical free flaps provide superior functional and aesthetic results with limited donor-site morbidity and are considered as a method of choice. The purpose of this article was to present the experience of our institution with free flaps used for reconstruction of various cutaneous and mucosal defects in the head and neck region. MATERIALS AND METHODS: This is a retrospective study of 9 consecutive patients who received free revascularized soft tissue flaps for reconstruction in the head and neck area. Among flaps performed in this group, there were: 7 radial forarm flaps, 1 anterolateral thigh flap, and 1 rectus abdominis myocutaneous flap. RESULTS: 7 of 9 flaps healed uneventfully. In 2 patients postoperative neck exploration was required due to neck hematoma with signs of compromised venous outflow from flaps. Both flaps were salvaged, however one of them developed partial necrosis. A normal oral diet and an intelligible speech were recovered in all patients. CONCLUSIONS: The use of microsurgical free flaps has proved to be a versatile, reliable and effective method of reconstruction in the head and neck area. Careful postoperative monitoring allows for early detection of flap compromise and appropriate surgical revision which lead to significant improvements in overall success rates.