Comparison of transepithelial and conventional photorefractive keratectomy in myopic and myopic astigmatism patients: a randomized contralateral trial.

BACKGROUND: To assess transepithelial photorefractive keratectomy (tPRK) in terms of corneal epithelial healing rate, postoperative pain, postoperative discomfort, and visual and refraction outcomes compared to mechanical epithelial debridement PRK (mPRK) and alcohol-assisted PRK (aaPRK). METHODS: In this double-masked, randomized clinical trial, thirty-nine patients underwent tPRK in one eye and mPRK in the fellow eye (arm A), and 33 patients underwent tPRK in one eye and aaPRK in the contralateral eye (arm B). All surgical procedures were done using the Schwind Amaris excimer laser. The area of corneal epithelial defect in all eyes was captured and analyzed using ImageJ software. RESULTS: Mean epithelial healing time was respectively 3.74 ± 0.82 and 3.59 ± 0.79 days in tPRK versus mPRK (P = 0.21) in arm A, and 3.67 ± 0.92 and 3.67 ± 0.74 days in tPRK versus aaPRK (P = 1.00) in arm B. Accounting for the initial corneal epithelial defect area, the epithelial healing rate was faster in conventional PRK groups compared to tPRK (both P<0.001) in both arms. However, there was no significant difference in safety, efficacy, spherical equivalent refractive accuracy, or corneal haze development between tPRK and conventional PRK groups (all P > 0.05). CONCLUSIONS: All three methods are effective in terms of visual and refractive outcomes. However, although time to complete re-epithelialization was similar with the three methods, the epithelial healing rate was faster in conventional PRK considering the initial corneal epithelial defect area, and the patients experienced less pain and discomfort in the first postoperative day. TRIAL REGISTRATION: IRCT, IRCT20200317046804N1 . Retrospectively registered 5 May 2020.

Purse-string suture versus full-thickness skin graft: An efficacy and safety comparison study.

Purse-string suture (PSS) and full-thickness skin graft (FTSG) are two different approaches to the closure of circular skin defects. In this study, we compare the feasibility and the aesthetic outcome of these two techniques in high operatory risk non-melanoma skin cancer (NMSC) patients. We performed a retrospective study on 65 patients, treated with PSS or FTSG, and evaluated after a minimum follow-up of 6 months. The post-surgery assessment was based on the Vancouver scar scale (VSS) and differences in terms of defect areas, operative and healing times were performed both with parametric and nonparametric tests. Operative times in PSS were significantly lower than those needed for FTSG, without perioperative adverse events; PSS required a waiting time before removing the suture greater than FTSG. After surgery, PSS resulted in a median defect area reduction of 73%. No significant differences were found in the median value for VSS in the two groups. Based on our clinical experience, the PSS advantages in terms of feasibility, rapidity of execution, and mean defect area reduction were confirmed. So, this technique seems to be appropriate for fragile patients affected by NMSC, that cannot hold long surgical sessions.

A Novel, Efficient, Unit Circle-Based, Method for Positioning and Operating Cryo-Surgical Probes in Convex Target Areas.

A novel method for positioning and operating needle-like cryo-surgical probes in 2D convex target areas is presented. The method is based on the recorded dynamic performance of a single probe, termed "unit circle," (UC) embedded in a semi-infinite, tissue-like medium. Up to 15 cryo-probes, inserted into the same depth, are operated uniformly for 2-5 min. A predetermined number of probes are rearranged inside the target area until a "tight configuration" is obtained. The probes are initially arranged inside the target area such that the "lethal temperature" circles produced by them are tangent to its contour and to both adjacent lethal temperature circles. Subsequently, all probes are repositioned inwardly, each at a specific distance that depends on the local radius of curvature of the target area. Resulting total "defect areas"-internal and external-for a number of demonstrated cases, amounted to between 2.5% and 7.6% of the target area. The lower values of the defect areas were obtained with increasing numbers of inserted probes coupled with shorter operating times. Possible freezing damages to regions beyond the target area were reduced by up to about 30% for these cases. Similar results were obtained for a case of combined convex-concave target area, treated with additional, externally inserted, heating probes.

Assessment of predictive factors for recurrence in laparoscopic ventral hernia repair using a bridging technique.

AIM: To assess the long-term incidence and predictive factors for recurrence after laparoscopic ventral hernia repair using a bridging technique. METHODS: The study group consisted of 213 consecutive patients operated by laparoscopy for primary ventral (n = 158) or incisional hernia (n = 55) between 2001 and 2014. Patients had a repair without fascia closure by intra-peritoneal onlay placement of a Parietex® composite mesh centred on the defect with an overlap of at least 3 cm. Clinical outcome was assessed by a combination of office consultation, patient's electronic medical file review and telephone interview. RESULTS: There were 144 men and 69 women with a mean age of 55 ± 12 years and a BMI of 32 ± 6. With a mean follow-up of 69 ± 44 months, a recurrent hernia was noted in 16 patients (7.5%). Univariate analysis showed a statistically significant higher recurrence rate in the following conditions: incisional hernia (15%), BMI ≥ 35 (21%), defect width >4 cm (27%), defect area >20 cm2 (27%), mesh overlap <5 cm (32%) and ratio of mesh area to defect area (M/D ratio) ≤12 (48%). Multivariate logistic analysis revealed that M/D ratio was the only independent predictive factor for recurrence (coefficient -0.79, OR 0.46, p < 0.002). With a M/D ratio ≤8, between 9 and 12, between 13 and 16, and ≥17, the recurrence rate was, respectively, 70, 35, 9 and 0% (p < 0.001). CONCLUSIONS: In laparoscopic repair of ventral hernia using a bridging technique, an overlap of at least 5 cm is not all that is required to prevent hernia recurrence. The M/D ratio is the most important predictive factor for recurrence. A ratio of 13 appears as the threshold under which that technique cannot be recommended and 16 as the threshold over which the risk of recurrence is virtually nil. If a satisfactory M/D ratio cannot be achieved, other surgical repair should be proposed to the patient.

Relationship between ventral hernia defect area and intra-abdominal pressure: dynamic in vivo measurement.

BACKGROUND: It is an acceptable concept that the ventral hernia defect area will increase with a rise in intra-abdominal pressure (IAP). The literature lacks the evidence about how much this increase is in vivo. The aim of this study was to objectively measure the change in the ventral hernia defect area with increasing intra-abdominal pressure. METHODS: In a prospective study of laparoscopic ventral hernia repair, the area of hernia defect was measured from inside the abdomen using a sterile paper ruler. The horizontal (width) and vertical (length) measurements of the defect were taken at two pressure points: (IAP = 8 mmHg) and (IAP = 15 mmHg). The hernia defect area was calculated as an oval shape using a standard formula. RESULTS: Eighteen consecutive patients with a ventral hernia were included in this study (8 males: 10 females). Median age was 60 years (30-81), body mass index (BMI) was 29.9 (22.6-37.6). Changing the IAP significantly, (P < 0.001) changed the values of horizontal and vertical measurements, and the calculated area of the ventral hernia defect. The median calculated defect area, as an oval shape, was 5.6 cm(2) (Q1-Q3 = 3.5-15.5) and 6.9 cm(2) (Q1-Q3 = 4.5-18.7) at 8 and 15 mmHg IAP, respectively. The calculated area of mesh required to cover the defect with a 5 cm overlap increased by a median of 5% (Q1-Q3 = 3-6%). The change in defect area did not differ significantly between obese and non-obese patients (P = 0.5). CONCLUSIONS: Dynamic, rather than static, measurements of ventral hernia area during laparoscopy provide a simple way of in vivo objective measurement that helps the surgeon choose the appropriate area of mesh. When choosing mesh area, we support the trend toward a larger overlap of at least 5 cm if less precise methods of measuring defect area are been used.

Association of the Stability Ratio With Postoperative Clinical Function and Recurrence of Instability in Patients With Anterior Shoulder Instability: A Retrospective Cohort Study.

Background: The stability ratio (SR) is used to assess the stability of the glenoid in anterior shoulder instability (ASI). However, the association between the SR and postoperative clinical function and instability recurrence after arthroscopic Bankart repair is unknown. Hypothesis: Patients with a higher SR would have better postoperative clinical scores and a lower incidence of recurrent instability than patients with a lower SR after arthroscopic Bankart repair. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 62 patients who underwent arthroscopic Bankart repair for ASI between 2013 and 2019 were enrolled. All patients had at least 2 years of follow-up data. The preoperative SR was calculated via biomechanical testing based on patient-specific 3-dimensional glenoid models, and patients were evenly divided into 2 groups: high SR (≥16.13%) and low SR (<16.13%). Baseline information (patient characteristics, clinical history, bone defect area [BDA], and SR), clinical scores at the final follow-up (Single Assessment Numerical Evaluation, Western Ontario Shoulder Index, and American Shoulder and Elbow Surgeons), and instability recurrence were compared between the 2 groups. Results: No significant differences were found in the baseline information between the high- and low-SR groups, except for the BDA (8.5% [high-SR group] vs 11.9% [low-SR group]; P = .01). No patients in the high-SR group had recurrent instability, while 6 patients (19.4%) had recurrent instability in the low-SR group (P = .02). Patients in the high-SR group had superior clinical outcomes compared with those in the low-SR group in terms of postoperative Western Ontario Shoulder Index scores (median, 205 vs 410, respectively; P = .006) and American Shoulder and Elbow Surgeons scores (median, 98.3 vs 95, respectively; P = .02). Conclusion: In the present study, the SR was significantly associated with postoperative clinical function and recurrence of instability after arthroscopic Bankart repair in patients with ASI.

Effects and metabolism of fish collagen sponge in repairing acute wounds of rat skin.

Objective: Study the repair effect of tilapia collagen on acute wounds, and the effect on the expression level of related genes and its metabolic direction in the repair process. Materials and methods: After the full-thickness skin defect model was constructed in standard deviation rats, the wound healing effect was observed and evaluated by means of characterization, histology, and immunohistochemistry. RT-PCR, fluorescence tracer, frozen section and other techniques were used to observe the effect of fish collagen on the expression of related genes and its metabolic direction in the process of wound repair. Results: After implantation, there was no immune rejection reaction, fish collagen fused with new collagen fibers in the early stage of wound repair, and was gradually degraded and replaced by new collagen in the later stage. It has excellent performance in inducing vascular growth, promoting collagen deposition and maturation, and re-epithelialization. The results of fluorescent tracer showed that fish collagen was decomposed, and the decomposition products were involved in the wound repair process and remained at the wound site as a part of the new tissue. RT-PCR results showed that, without affecting collagen deposition, the expression level of collagen-related genes was down-regulated due to the implantation of fish collagen. Conclusion: Fish collagen has good biocompatibility and wound repair ability. It is decomposed and utilized in the process of wound repair to form new tissues.

Measurement of the Balance Stability Angle to Predict the Stability Ratio in Patients With Recurrent Anterior Shoulder Dislocation: A Novel Computed Tomography-Based Protocol.

Background: The stability ratio (SR) is an important biomechanical parameter for evaluating glenoid stability in patients with recurrent anterior shoulder dislocation (RASD), and it cannot be practically and conveniently measured in clinical scenarios. Purpose: To investigate a novel computed tomography (CT)-based protocol to estimate the SR efficiently. Study Design: Descriptive laboratory study. Methods: A total of 102 patients with RASD were included. Demographic information, CT scans, and bone defect area (BDA) were collected. The new protocol, based on balance stability angle (BSA) measurements on CT, was conducted to estimate the SR (SRCT) by 2 surgeons independently. Biomechanical testing was then performed on patient-specific 3-dimensional (3D)-printed glenoid models to calculate the SR (SR3Dprint), which was used to (1) analyze the reliability of SRCT and (2) examine if the BDA could predict SR3Dprint. To validate whether the 3D-printed glenoid could reflect the actual biomechanical properties of the shoulder, the SR from 5 cadaveric glenoid specimens (SRcadaver) was also calculated and compared with that from the 3D-printed glenoid (SR3Dprint) under 6 osteotomy conditions. Linear regression and intraclass correlation coefficients (ICCs) were used for statistical analysis. Results: The interrater reliability of SRCT measurements was high (ICC = 0.95). SRCT was highly correlated with SR3Dprint (R 2 = 0.86; ICC = 0.92). The mean BDA was 11.44% ± 6.72% by the linear ratio method, with a weak correlation with SR3Dprint (R 2 = 0.31; ICC = -0.46). The cadaveric validation experiment indicated that SRcadaver was highly correlated with SR3Dprint (R 2 = 0.86; ICC = 0.77). Conclusion: Results indicated that (1) the proposed CT-based protocol of obtaining BSA measurements is promising for the SR estimation in patients with RASD, (2) the BDA was not an effective parameter to predict the biomechanical SR, and (3) the 3D-printed glenoid could reflect the biomechanical properties of cadaveric shoulders regarding the SR estimation. Clinical Relevance: Traditional BDA measurements cannot accurately reflect the biomechanical stability of the glenoid. The newly proposed CT-based protocol is practical for surgeons to estimate the SR.

A new criterion to predict recurrence after laparoscopic ventral hernia repair: mesh/defect area ratio.

<b>Introduction:</b>Minimizing recurrence in hernia surgery is one of the major aims. Defining surgeon-dependent risk factors for recurrence is therefore of great importance in laparoscopic ventral hernia repair (LVHR). This study aims to analyze the predictive value of the mesh area/defect area ratio (M/D ratio) in terms of recurrence as a new criterion in LVHR.</br> </br> <b>Methods:</b> A total of 124 patients were enrolled in the study. Age, gender, hernia type, body mass index, defect size, size of the mesh, mesh overlapping, area of the defect, area of the mesh, M/D ratio, postoperative complications, follow-up time, recurrences and timing of recurrence were also recorded. The potential variables that may affect recurrence were examined by univariate and multivariate analysis.</br> </br> <b>Results:</b> There were 12 (9.7%) recurrences in our series. A statistically significant difference was found if either the mesh/defect ratio was ≤6 or >6 (p = 0.012). Multivariate analysis confirmed that M/D ratio was the only independent parameter for recurrence. </br></br><b>Conclusion:</b> Understanding M/D ratio concept and using it in surgical clinical practice may help reduce recurrence rates after LVHR.</br>.

Head-compliant microstrip split ring resonator for non-invasive healing monitoring after craniosynostosis-based surgery.

A soft and highly directive, proximity-coupled split-ring resonator fabricated with a liquid alloy, copper and polydimethylsiloxane (PDMS) is presented. The same was designed for sensing osteogenesis of calvarial bone. As dielectric properties of bone grafts in ossifying calvarial defects should change during the osteogenesis process, devices like this could monitor the gradual transformation of the defect into bone by differentiating changes in the dielectric properties as shifts in the resonance frequency. Computational Software Technology (CST) Microwave Studio®-based simulation results on computational head models were in good agreement with laboratory results on head phantom models, which also included the comparison with an in-vivo measurement on the human head. A discussion based on an inductive reasoning regarding dynamics' considerations is provided as well. Since the skin elasticity of newborn children is high, stretching and crumpling could be significant. In addition, due to typical head curvatures in newborn children, bending should not be a significant issue, and can provide higher energy focus in the defect area and improve conformability. The present concept could support the development of soft, cheap and portable follow-up monitoring systems to use in outpatient hospital and home care settings for post-operative monitoring of bone healing after reconstructive surgical procedures.

Effect of different defect areas of medial femoral condyle cartilage on peripheral cartilage stress: Three-dimensional finite element analysis / 中国组织工程研究

BACKGROUND: Although it has been found in many studies that three-dimensional finite element analysis can be used in the study of knee joint biomechanics, there are few researches on different defect areas of medial condyle cartilage of the femur. OBJECTIVE: To analyze the stress change trend of perimeter articular cartilage before and after the occurrence of different defect areas of medial femoral condyle cartilage, providing biomechanical data for patients with knee medial femoral condyle cartilage defect. METHODS: One normal adult had been selected to establish a three-dimensional finite element model. Material mechanical properties were input to Abaques software with divided grid model. After controlling boundary condition with mechanical load, structural nonlinear finite element was calculated. First, the load stress distribution of knee cartilage and meniscus was observed under normal stress. Articular cartilage stress distribution was observed with load conditions in different defects (0, 6, 8, 10, 12, 14, 16, 18 and 20 mm) of medial femoral condyle. The stress changes on the cartilage were analyzed during the defect of medial femoral condyle. This study was approved by the Ethics Committee of First Affiliated Hospital of Kunming Medical University. The volunteer signed the informed consent. RESULTS AND CONCLUSION: (1) Material properties, boundary conditions and the introduction of loads were defined successfully. The stress cloud chart and its stress data were obtained from different diameter defects of cartilage in medial condyle of knee joint. According to statistical analysis, the stress on the femoral condyle and tibial plateau cartilage had significant changes compared with no defects when the medial femoral condyle cartilage had defects of 10 mm (area 0. 78 cm2) and 12 mm (area 1. 13 cm2). (2) The stress change trend of the cartilage of the medial condyle of the knee joint under the condition of different diameter defects was calculated based on the analysis of the application of three-dimensional finite element method. (3) Results suggest that the defect with the diameter of 10 mm (area 0. 78 cm2) of medial femoral condyle may be the minimum diameter advised for operation intervention of cartilage repair.

Comparison of MRI and arthroscopy on defect area measurement of knee joint cartilage / 实用放射学杂志

Objective To explore the consistency of knee articular cartilage defect area by magnetic resonance imaging (MRI)and arthroscopy.Methods Thirty-six patients (36 knees)with knee cartilage lesions were collected in our study.The defect area meas-urement of knee articular cartilage by MRI and arthroscopy was compared.Results A total of 92 lesions were detected by both MRI and arthroscopy with an average of 2.6 defects per knee.Preoperative MRI resultes demonstrated the mean defect area per knee was (1.9±1.5)cm2 ,while arthroscopic measurement after debridement indicated the mean defect area per knee was (2.9±2.6)cm2 , which had significant difference(P <0.001).The area measured by MRI was less than that by arthroscopy,and the mean difference was (1.7 ± 1.1)cm2 .The mean area measured by MRI was 70.1% of that by arthroscopy.Conclusion Arthroscopy and MR have good consistency in the number of articular cartilage defect lesions .MRI can reflect the knee articular cartilage defect area directly or indirectly,and be capable of accurate positioning and qualitative diagnosis.

A Size Change of Bone Defect Area after Autogenous Calvarial Bone Graft

Calvarial bone grafting in craniomaxillofacial trauma and facial reconstructive surgery is now widely recognized and accepted as a standard procedure. One of the commonly reported problems of calvarial bone graft is the contour defect caused by partial resorption of the graft. But, there are few reports that discuss the fate of the calvarial bone graft based on the quantitative data. In this article, the changes of grafted calvarial bone were evaluated using 3-dimensional computed tomography(CT). 9 patients were observed with the CT scans at 2mm thickness immediately after operation and at the time of last follow-up. The area of the bone defect was segmented on the 3-dimensional CT image and calculated by AnalyzeDirect 5.0 software. The immediate postoperative bone defect area of the recipient site and the donor site were 612.9mm2 and 441.5mm2, respectively, which became 1028.1mm2 and 268.8mm2, respectively at the last follow-up. In conclusion, the bone defect area was less increased on the donor site of calvarial bone graft than on the recipient site. And the CT scan is a valuable imaging method to assess and follow-up the clinical outcome of calvarial bone grafting.