Aims
Immune‐mediated type 1 diabetes (T1D) in adulthood and latent autoimmune diabetes in adults (LADA) share similar pathological mechanisms but differ clinically in disease progression. The aim of ...this study was to acquire insights into spontaneous and stimulated chemokine secretion of immune cells in different diabetes types.
Materials and Methods
We investigated in vitro spontaneous, mitogen (PI) and antigen (HSP60, p277, pGAD, pIA2) stimulated chemokine secretion of leucocytes from patients with T1D (n = 32), LADA (n = 22), type 2 diabetes (T2D; n = 49), and glucose‐tolerant individuals (n = 13). Chemokine concentration in supernatants was measured for CCL2 (MCP‐1), CXCL10 (IP10) and CCL5 (RANTES) using a multiplex bead array assay.
Results
Spontaneous secretion of CCL2 and CCL5 were higher in LADA compared to T1D and T2D (all p < 0.05) while CXCL10 was similar in the groups. Mitogen‐stimulated secretion of CCL2 in LADA was lower compared to T1D and T2D (all p < 0.05) while CXCL10 and CCL5 were similar in all groups. Upon stimulation with pIA2 the secretion of CCL2 in LADA was lower compared to T2D (p < 0.05). Spontaneous CXCL10 secretion in LADA was positively associated with body mass index (r2 = 0.35; p = 0.0035) and C‐peptide (r2 = 0.30; p = 0.009).
Conclusions
Chemokine secretion is altered between different diabetes types. Increased spontaneous secretion of CCL2 and CCL5 and decreased secretion of CCL2, upon stimulation with PI and pIA2, in LADA compared to T1D and T2D could reflect altered immune responsiveness in LADA patients in association with their slower clinical progression compared to insulin dependence.
Purpose
Arterial hypertension (AHTN), type 2 diabetes mellitus (DM), and atherosclerotic vascular disease (ASVD) are common vascular comorbidities in patients undergoing reconstruction of the head ...and neck region with a microvascular free flap. These conditions may affect flap perfusion (microvascular blood flow and tissue oxygenation), which is a prerequisite for flap survival and thus reconstruction success. This study aimed to investigate the impacts of AHTN, DM, and ASVD on flap perfusion.
Methods
Data from 308 patients who underwent successful reconstruction of the head and neck region with radial free forearm flaps, anterolateral thigh flaps, or fibula free flaps between 2011 and 2020 were retrospectively analyzed. Flap perfusion was measured intraoperatively and postoperatively with the O2C tissue oxygen analysis system. Flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation were compared between patients with and without AHTN, DM, and ASVD.
Results
Intraoperative hemoglobin oxygen saturation and postoperative blood flow were lower in patients with ASVD than in patients without ASVD (63.3% vs. 69.5%,
p
= 0.046; 67.5 arbitrary units AU vs. 85.0 AU,
p
= 0.036; respectively). These differences did not persist in the multivariable analysis (all
p
> 0.05). No difference was found in intraoperative or postoperative blood flow or hemoglobin oxygen saturation between patients with and without AHTN or DM (all
p
> 0.05).
Conclusion
Perfusion of microvascular free flaps used for head and neck reconstruction is not impaired in patients with AHTN, DM, or ASVD. Unrestricted flap perfusion may contribute to the observed successful use of microvascular free flaps in patients with these comorbidities.
INTRODUCTIONThe soleus perforator flap and the peroneal perforator flap could be alternatives to the radial forearm flap for head and neck reconstruction. However, their flap dimensions remain ...unknown. This study aims to determine the dimensions of both flaps and allow preoperative planning for reconstruction based on clinical parameters. MATERIALS & METHODSComputed tomography records of 296 patients dated from 2009 through 2019 were retrospectively analyzed. Virtual three-dimensional flap models of the soleus perforator flap and peroneal perforator flap were aligned to segmented leg models, and flap thickness and volume were determined. Associations of flap thickness and volume with clinical parameters were evaluated, and a calculation method was derived. RESULTSThe soleus perforator flap had an average thickness of 8.7 mm (4.8 mm) and an average volume of 0.9 cm³ (0.5 cm³) per square centimeter surface area. The peroneal perforator flap had an average thickness of 6.4 mm (3.8 mm) and an average volume of 0.8 cm³ (0.4 cm³) per square centimeter surface area. The soleus perforator flap was thicker and more voluminous than the peroneal perforator flap (both p<0.001). For both flaps, leg circumference was the strongest predictor of flap thickness (ß=0.524, p<0.001 and ß=0.700, p<0.001, respectively) and flap volume (ß=0.535, p<0.001 and ß=0.712, p<0.001, respectively). CONCLUSIONDimensions of the soleus perforator and the peroneal perforator flaps are similar to those of the radial forearm flap. Preoperative planning of flap dimensions, such as flap thickness and volume, can help the surgeons select the appropriate flap.
Background In microvascular head and neck reconstruction, ischemia of the free flap tissue is inevitable during microsurgical anastomosis and may affect microvascular free flap perfusion, which is a ...prerequisite for flap viability and a parameter commonly used for flap monitoring. The aim of this study was to investigate the influence of the number of ischemia intervals and ischemia duration on flap perfusion. Methods Intraoperative and postoperative flap blood flow, hemoglobin concentration, and hemoglobin oxygen saturation at 2 and 8 mm tissue depths, as measured with the O2C tissue oxygen analysis system, were retrospectively analyzed for 330 patients who underwent microvascular head and neck reconstruction between 2011 and 2020. Perfusion values were compared between patients without (control patients) and with a second ischemia interval (early or late) and examined with regard to ischemia duration. Results Intraoperative and postoperative flap blood flow at 8 mm tissue depth were lower in patients with early second ischemia intervals than in control patients 102.0 arbitrary units (AU) vs 122.0 AU, P = .030; 107.0 AU vs 128.0 AU, P = .023. Both differences persisted in multivariable analysis. Intraoperative and postoperative flap blood flow at 8 mm tissue depth correlated weakly negatively with ischemia duration in control patients ( r = −.145, P = .020; r = −.124, P = .048). Both associations did not persist in multivariable analysis. Conclusions The observed decrease in microvascular flap blood flow after early second ischemia intervals may reflect ischemia-related vascular flap tissue damage and should be considered as a confounding variable in flap perfusion monitoring.
The myocutaneous anterolateral thigh (ALT) and vastus lateralis (VL) flaps include a large muscle mass and a sufficient vascular pedicle, and they have been used for decades to reconstruct traumatic ...and acquired defects of the head and neck and extremities. In spite of these benefits, musculoskeletal dysfunction was reported in nearly 1 out of 20 patients at follow-up. It is unclear whether the recently proposed muscle-sparing flap-raising approach could preserve VL muscle function and whether patients at increased risk could benefit from such an approach. Therefore, we performed a predictive dynamic gait simulation based on a biological motion model with gradual weakening of the VL during a self-selected and fast walking speed to determine the compensable degree of VL muscle reduction. Muscle force, joint angle, and joint moment were measured. Our study showed that VL muscle reduction could be compensated up to a certain degree, which could explain the observed incidence of musculoskeletal dysfunction. In elderly or fragile patients, the VL muscle should not be reduced by 50% or more, which could be achieved by muscle-sparing flap-raising of the superficial partition only. In young or athletic patients, a VL muscle reduction of 10%, which corresponds to a muscle cuff, has no relevant effect. Yet, a reduction of more than 30% leads to relevant weakening of the quadriceps. Therefore, in this patient population with the need for a large portion of muscle, alternative flaps should be considered. This study can serve as the first basis for further investigations of human locomotion after flap-raising.
Over the last few decades it has been shown that nasoalveolar molding (NAM) has had an effect on the correction of nasal cartilage deformities and the alveolar process. This three-dimensional (3D) ...analysis evaluated the effects of NAM on the alveolar cleft region in patients with unilateral cleft lip and palate.
Alveolar gap volumes were measured in a retrospective review of 40 dental casts of 20 patients with unilateral clef lip and palate before and after treatment. Ten patients who began undergoing NAM immediately after birth were included in this study. An additional 10 patients with unilateral clefts but without NAM were included as a control group. All of the casts (pretreatment and post-treatment) were 3D scanned, and the cleft volumes and anterior gap widths underwent computer-aided evaluations.
NAM resulted in a significant reduction (p < 0.05) in alveolar gap volume and anterior cleft width from birth until lip closure time, while half of the control group showed slight increases in cleft volume. Based on these results, NAM is an effective and helpful treatment that can be used to significantly reduce alveolar gap volume and anterior cleft width in patients with unilateral clefts. Harmonization of the dental arch and a reduction in the alveolar cleft region are desirable treatment goals.
Orbital floor fractures result in critical changes in the shape and inferior rectus muscle (IRM) position. Radiological imaging of IRM changes can be used for surgical decision making or prediction ...of ocular symptoms. Studies with a systematic consideration of the orbital floor defect ratio in this context are missing in the literature. Accordingly, this study on human cadavers aimed to systematically investigate the impact of the orbital floor defect ratio on changes in the IRM and the prediction of posttraumatic enophthalmos.
Seventy-two orbital floor defects were placed in cadaver specimens using piezosurgical removal. The orbital defect area (ODA), orbital floor area (OFA), position and IRM shape, and enophthalmos were measured using computed tomography (CT) scans.
The ODA/OFA ratio correlated significantly (p < 0.001) with the shape (Spearman’s rho: 0.558) and position (Spearman’s rho: 0.511) of the IRM, and with enophthalmos (Spearman’s rho: 0.673). Increases in the ODA/OFA ratio significantly rounded the shape of the IRM (ß: 0.667; p < 0.001) and made a lower position of the IRM more likely (OR: 1.093; p = 0.003). In addition, increases in the ODA/OFA ratio were significantly associated with the development of relevant enophthalmos (OR: 1.159; p = 0.008), adjusted for the defect localization and shape of the IRM. According to receiver operating characteristics analysis (AUC: 0.876; p < 0.001), a threshold of ODA/OFA ratio ≥ 32.691 for prediction of the risk of development of enophthalmos yielded a sensitivity of 0.809 and a specificity of 0.842.
The ODA/OFA ratio is a relevant parameter in the radiological evaluation of orbital floor fractures, as it increases the risk of relevant enophthalmos, regardless of fracture localization and shape of the IRM. Therefore, changes in the shape and position of the IRM should be considered in surgical treatment planning. A better understanding of the correlates of isolated orbital floor fractures may help to develop diagnostic scores and standardize therapeutic algorithms in the future.
Abstract Purpose The orbital floor is frequently involved in head trauma. Current evidence on the use of reconstruction materials for orbital floor repair is inconclusive. Accordingly, this study ...aimed to compare the impact of polydioxanone (PDS) foil thickness on reconstruction of the orbital geometry after isolated orbital floor fractures. Methods Standardized isolated orbital floor fractures were symmetrically created in 11 cadaver heads that provided 22 orbits. PDS foils with thicknesses of 0.25–0.5 mm were inserted. Computed tomography (CT) scans of the native, fractured, and reconstructed orbits were obtained, and orbital volume, orbital height, and foil bending were measured. Results Orbital volume and height significantly ( p < 0.01) increased after the creation of isolated orbital floor fractures and significantly ( p = 0.001) decreased with overcorrection of the orbital geometry after orbital floor reconstruction with PDS 0.25 mm or PDS 0.5 mm. The orbital geometry reconstruction rate did not differ significantly with respect to foil thickness. However, compared to PDS 0.5 mm, the use of PDS 0.25 mm resulted in quantitatively higher reconstructive accuracy and a restored orbital volume that did not significantly differ from the initial volume. Conclusion Orbital floors subjected to isolated fractures were successfully reconstructed using PDS regardless of foil thickness, with overcorrection of the orbital geometry. Due to its lower flexural stiffness, PDS 0.25 mm appeared to provide more accurate orbital geometry reconstruction than PDS 0.5 mm, although no significant difference in reconstructive accuracy between PDS 0.25 mm and PDS 0.5 mm was observed in this cadaveric study.
Although surgical suturing is one of the most important basic skills, many medical school graduates do not acquire sufficient knowledge of it due to its lack of integration into the curriculum or a ...shortage of tutors. E-learning approaches attempt to address this issue but still rely on the involvement of tutors. Furthermore, the learning experience and visual-spatial ability appear to play a critical role in surgical skill acquisition. Virtual reality head-mounted displays (HMDs) could address this, but the benefits of immersive and stereoscopic learning of surgical suturing techniques are still unclear.
In this multi-arm randomized controlled trial, 150 novices participated. Three teaching modalities were compared: an e-learning course (monoscopic), an HMD-based course (stereoscopic, immersive), both self-directed, and a tutor-led course with feedback. Suturing performance was recorded by video camera both before and after course participation (>26 hours of video material) and assessed in a blinded fashion using the OSATS Global Rating Score (GRS). Furthermore, the optical flow of the videos was determined using an algorithm. The number of sutures performed was counted, visual-spatial ability was measured with the mental rotation test (MRT), and courses were assessed with questionnaires.
Students' self-assessment in the HMD-based course was comparable to that of the tutor-led course and significantly better than in the e-learning course (P=0.003). Course suitability was rated best for the tutor-led course (x̄=4.8), followed by the HMD-based (x̄=3.6) and e-learning (x̄=2.5) courses. The median ΔGRS between courses was comparable (P=0.15) at 12.4 (95% CI 10.0-12.7) for the e-learning course, 14.1 (95% CI 13.0-15.0) for the HMD-based course, and 12.7 (95% CI 10.3-14.2) for the tutor-led course. However, the ΔGRS was significantly correlated with the number of sutures performed during the training session (P=0.002), but not with visual-spatial ability (P=0.626). Optical flow (R2=0.15, P<0.001) and the number of sutures performed (R2=0.73, P<0.001) can be used as additional measures to GRS.
The use of HMDs with stereoscopic and immersive video provides advantages in the learning experience and should be preferred over a traditional web application for e-learning. Contrary to expectations, feedback is not necessary for novices to achieve a sufficient level in suturing; only the number of surgical sutures performed during training is a good determinant of competence improvement. Nevertheless, feedback still enhances the learning experience. Therefore, automated assessment as an alternative feedback approach could further improve self-directed learning modalities. As a next step, the data from this study could be used to develop such automated AI-based assessments.
Introduction
In free flaps, 5%–10% of complications are related to failure of sutured vascular anastomoses. Adhesive‐based microvascular anastomoses are potential alternatives but are associated with ...failure rates of 70% in research studies. VIVO is a new adhesive with slow biodegradation within 6 months that has shown a 100% patency rate in research studies over 2 h observation time but long‐term patency has not been evaluated. The authors hypothesize that VIVO will enable a reliable microvascular procedure comparable to sutured anastomoses over a 28‐day period.
Materials and Methods
The right common carotid artery of 60 male Sprague Dawley rats, ~450 g, were used for microvascular end‐to‐end anastomosis. VIVO was applied with reduced sutures with a temporary catheter in one group and in the other with a custom‐shaped memory stent. Anastomoses with eight interrupted sutures served as control. All groups were n = 20. Anastomosis time and bleeding were recorded for each procedure. Doppler flowmetry was performed 20 min, 1, 10, and 28 days postoperatively. Postmortem toluidine staining was used for semi‐quantitative analysis of stenosis, thrombosis, necrosis, and aneurysm formation by histologic evaluation.
Results
No occlusion was detected 20 min and 1 day postoperative, and after 28 days of observation in all anastomoses. The anastomosis time of the VIVO with catheter group was about 32% significantly faster than the VIVO with stent group. In the VIVO group with stent, the bleeding time was ~80% shorter than in the control group with 2.1 ± 0.3 and VIVO with catheter 2.0 ± 0.5 (p ≤ .001 each). Minor and nonsignificant stent‐associated thrombus formation and stent‐typical intraluminal stenosis were detected exclusively in the VIVO with stent group.
Conclusion
Within the limitations of a rat study, the use of VIVO in anastomosis showed promising results. VIVO with catheter was found to be advantageous.
PDF
