Mapping of Thoracodorsal Artery Perforators: Accuracy of Thermography and Handheld Doppler

BACKGROUND

 The versatile musculocutaneous latissimus dorsi flap and the thoracodorsal artery (TDA) perforator flap have developed into indispensable approaches in reconstructive surgery. While the anatomy of the TDA is consistent, the skin perforators vary in location and course. Dynamic infrared thermography (DIRT) recently gained popularity for perforator identification; however, its use and accuracy in thoracodorsal artery perforator (TDAP) mapping is yet to be determined.

METHODS

 TDAPs were visualized in 50 cases by DIRT. Based on the thermographic hotspots, the corresponding perforators were then identified by color duplex ultrasound (CDU) and handheld Doppler in a blinded fashion by two separate examiners.

RESULTS

 The midpoint of all perforator fascia passages was localized 99.7 mm caudal and 13.5 mm medial of the posterior axillary fold. The positive predictive value of perforator identification by dynamic infrared thermography was 86.5% and the correlating perforator fascia passage was 9.9 ± 5.8 mm from the hotspot midpoint, with a maximum of 29 mm. The positive predictive value of perforator identification by handheld Doppler was 95% and the signal was 7.2 ± 5.1 mm from the perforator fascia passage.

CONCLUSION

 DIRT precisely localizes TDAPs. The fusion with CDU combines both modalities' advantages. The combination with handheld Doppler is a fast way of perforator imaging, decreasing the handheld Dopplers' high false positive rate.

Postoperative scaphoid alignment, smoking, and avascular necrosis mostly influence union rate after scaphoid reconstruction: Results from a retrospective single center study involving 370 patients

Current literature does not definitely demonstrate the superiority of any particular scaphoid reconstruction method. The primary goal of this retrospective single center study was to evaluate the influence of reconstruction techniques and other factors on the union rate after reconstruction of scaphoid nonunions. In the study, 370 patients with nonunions classified as stable (Mayo 1) or unstable (Mayo 2) depending on carpal alignment were included. Minimal radiological follow-up was 3 months. Bone healing after scaphoid reconstruction was evaluated using computer tomography scans in 294 and radiograms in 76 patients. Univariate and multivariate logistic regressions were applied in the analysis. Eight statistically significant factors that influenced the union rate were fixation method, type of previous operations, number of all operations, number of reconstructions, smoking, postoperative pathological lateral intrascaphoid angle (LISA>45°), avascular necrosis (AVN), and stability of nonunion. Smoking and postoperative LISA>45° significantly reduced the probability of bone fusion by approximately 4.4 and 9.5 times, respectively. Patients with reduced vascularity in the nonunion site had a 5.2 times lower chance of bone fusion. Our multivariate logistic regression model can explain 32% of failures after scaphoid reconstruction, including postoperative LISA>45°, patients' present record of smoking, and reduced vascularity in the nonunion site. However, bone graft type does not impact the union rate in general; however, in case of AVN, the tendency toward higher union rates was observed for medial femoral condyle free flaps when compared to other types of graft (non-vascularized and pedicled bone grafts considered as one group, p = 0.09).

The Impact of Blue Light Irradiation on Keratinocytes in Vitro

BACKGROUND

This study examined the effects of irradiation with blue light on HaCaT keratinocytes. As irradiation with blue light is known to be antimicrobial, it offers a promising alternative therapy for contaminated wounds. There is evidence that red light promotes wound healing, but the potential benefits of irradiation with blue light have not yet been adequately investigated.

METHODS

The rate of wound closure in sterile and contaminated cells was measured using an in vitro scratch assay wound-healing model. Additionally, cell viability after treatment was determined using a Sulforhodamine B (SRB) assay.

RESULTS

In both the sterile and contaminated groups, treated cells showed delayed wound closure when compared with cells not irradiated with blue light. Additionally, treatment with blue light resulted in poorer viability in the treatment groups.

CONCLUSION

Although irradiation with blue light may offer a promising alternative therapy for reducing bacterial colonization, our data indicate that re-epithelization may be negatively influenced by blue light. Further research is needed to clarify possible wound healing applications.

The corticocancellous press fit iliac crest bone dowel for recalcitrant scaphoid nonunion: analysis of union rate and clinical outcome

INTRODUCTION

Scaphoid nonunion after failed primary treatment remains challenging particularly when entailed by bone loss, avascular necrosis or deformity. We describe a scaphoid augmentation and fixation technique for cases of recalcitrant nonunion after screw placement by autologous press fit corticocancellous dowel. This study aims to provide reliable data on clinical and radiological outcomes and to contextualize in the face of other treatment options.

MATERIAL AND METHODS

The study included 16 patients with recalcitrant nonunion of the scaphoid. All patients received screw removal and scaphoid reconstruction by a dowel shaped non-vascularized corticocancellous bone graft from the iliac crest facilitating packing of the screw channel. Bone union, the scapholunate, radiolunate and intrascaphoidal angles were evaluated on X-ray and CT images, range of motion noted. Additionally grip strength, DASH and Green O'Brien scores were obtained from eight patients.

RESULTS

A union rate of 73% was noted after mean follow-up of 54 months. After revisional reconstruction of the scaphoid an extension-flexion rate of 84% of the healthy side was noted while pronation-supination reached 101%. DASH score averaged at 2.9, rest pain on a numeric rating scale was 0.43 with 99% peak grip force of the healthy side.

CONCLUSION

In complex cases of revisional scaphoid nonunion after screw placement, the corticocancellous iliac crest pressfit dowel is an option for augmentation and stabilization of the scaphoid by preserving the articular surface.

LEVEL OF EVIDENCE

IV, retrospective case series.

Optimization of the preoperative requirements of blood units for the surgical treatment of extra-abdominal soft tissue sarcoma: the TRANSAR score

Background and objectives

Excessive preoperative blood orders frequently occur during the preoperative planning of resections of sarcomas. We aimed to develop a prediction score model that would be able to identify a patient cohort in which the cross-matching could be safely evaded.

Patients and methods

We retrospectively analyzed data of 309 consecutive patients with extra-abdominal soft tissue sarcomas treated between September 2012 and December 2014. Scorecard scores for variables were calculated and summarized to a total score that can be used for risk stratification. The score was used in a logistic regression model. Results of the optimized model were described as a receiver operating characteristic curve.

Results

Preoperative units of red blood cells were requested for 206 (66.7%) patients, of which only 31 (10%) received them. Five parameters were identified with high predictive power. In the visualized barplot, there was an increased risk of blood transfusion with a higher score of TRANSAR.

Conclusion

A TRANSAR score is a new tool that can predict the probability of transfusion for patients with sarcoma. This may reduce the number of preoperative cross-matching and blood product ordering and associated costs without compromising patient care.

Precision of Dynamic Infrared Thermography in Anterolateral Thigh Flap Planning: Identification of the Perforator Fascia Passage

Background The anterolateral thigh (ALT) flap is commonly utilized in reconstructive surgery. Preoperative perforator mapping facilitates dissection. Dynamic infrared thermography can be applied to identify ALT perforators. However, its accuracy has not been evaluated in detail before. Therefore, this study aimed to assess the precision of dynamic infrared thermography in ALT perforator localization.

Methods The survey site was defined as a 25 × 8 cm rectangle on the anterolateral thigh and a coordinate system was established. The area was examined consecutively by dynamic infrared thermography with a FLIR ONE camera after 2-minute fan precooling. Two surgeons then independently performed color duplex ultrasound on the basis of the identified hotpots.

Results Twenty-four healthy subjects were examined. About 74.8% of perforators were musculocutaneous or musculoseptocutaneous. The mean distance between study area center and perforator or hotspot center was 51.8 ± 27.3 and 46.5 ± 26.2 mm, respectively. The mean distance from hotspot center to sonographic perforator fascia passage was 15.9 ± 9.9 mm with a maximum of 48.4 mm. The positive predictive value of thermographic ALT perforator identification was 93%.

Conclusion Thermographic hotspot and perforator location diverge widely in ALT flaps. Dynamic infrared thermography can therefore not be used as standalone technique for preoperative ALT perforator identification. However, the application before color duplex ultrasound examination is a reasonable upgrade and can visualize angiosomes and facilitate the examination.

Does leg dominance influence anterolateral thigh flap perforators?

INTRODUCTION

Thorough knowledge of perforator anatomy can facilitate anterolateral thigh (ALT) free flap harvest. The selection of the right or left thigh as donor area may be supported by preoperative perforator imaging and practical considerations. The study aims to determine if the leg dominance should be taken into account, when choosing the donor thigh for ALT free flap harvest, as muscle mass and perfusion might influence perforator quantity.

METHODS

ALT perforators were localized by color-coded duplex sonography and dynamic infrared thermography on both thighs within a defined 250 × 80 mm area in 24 subjects. Perforator number and thickness of subcutaneous tissue and muscle layer were compared in dominant and nondominant legs.

RESULTS

We found no statistically significant difference comparing sonographically identified ALT perforator numbers and hot spot numbers in dominant and nondominant legs. Yet, we found high interindividual differences. The comparison of subcutaneous tissue and muscle thickness yielded no significant difference.

CONCLUSIONS

Our study yielded no evidence for preference of the dominant or nondominant leg in ALT free flap harvesting. As we found high interindividual differences in perforator number, we suggest to rely on preoperative perforator imaging when choosing the ALT free flap donor thigh.

Thermography Supported Color Duplex Ultrasound Accelerates ALT Perforator Imaging

BACKGROUND

 The anterolateral thigh flap is a versatile and dependable perforator flap and is a popular choice in the reconstruction of various body sites. The variable perforator anatomy suggests preoperative perforator imaging to improve safety and speed of dissection. An innovative perforator imaging technique is thermography, which lately gained attention in plastic surgery.

METHODS

 Thirty-two healthy participants were included in this randomized study. One thigh was examined with dynamic infrared thermography and consecutively with ultrasound, while the contralateral thigh was examined with ultrasound as standalone technology.

RESULTS

 The application of dynamic infrared thermography prior to ultrasound perforator identification significantly accelerated the ultrasound examination duration by 90 to 130 seconds. The mean duplex ultrasound examination duration correlated positively with the hotspot and perforator quantity per thigh.

CONCLUSION

 The addition of thermographic perforator mapping can accelerate color duplex ultrasound anterolateral thigh perforator imaging. Furthermore, thermography supplements color duplex ultrasound with crucial information on angiosome location.

Septic arthritis of the wrist: a retrospective review of 39 cases

LEVEL OF EVIDENCE

III.

Immune-modulating properties of blue light do not influence reepithelization in vitro

Phototherapy is gaining more attention in the treatment of various diseases. Especially, blue light seems to be a promising approach for wound healing promotion due to its antimicrobial and immune-modulating properties. Despite this, there is only little research focusing on the immune-modulating properties of blue light and its possible effects on wound healing. Therefore, we investigated the effects of blue light irradiation on peripheral blood mononuclear cells (PBMC) and the influence on reepithelization in vitro. PBMCs were irradiated with DermoDyne® (DermoDyne HealthCare, Berlin, Germany) and effects on cell viability, cytokine expression, and scratch wound closure were evaluated afterwards. Irradiated cells showed a higher Interleukin-γ concentration while irradiation reduced resazurin concentration in a time-dependent manner. No differences in reepithelization were detectable when keratinocytes were treated with the supernatant of these blue light irradiated PBMCs. Blue light-mediated ex vivo stimulation of PBMCs does not cause faster reepithelization in an in vitro setting. Further research is needed to investigate the wound healing effects of phototherapy with blue light.

Air Flow Cooling Improves Anterolateral Thigh Perforator Mapping Using the FLIR ONE Thermal Camera

BACKGROUND

 Due to the variable vascular anatomy preoperative perforator mapping facilitates anterolateral thigh (ALT) free flap harvesting. Dynamic infrared perforator imaging can assist preoperative planning by displaying hot spots that represent angiosomes. This study aims to compare previously described precooling methods to develop a standardized simplified protocol for ALT perforator planning.

METHODS

 Fifty thighs were examined with a FLIR ONE thermal camera. Four different cold challenges, including alcoholic disinfection, wet laparotomy sponge cooling, fan cooling, and cold pack application, were compared. Hot spot locations within a 250 mm × 80 mm area were compared double-blinded to perforator locations determined by Doppler ultrasonography considered as gold standard.

RESULTS

 The matching rate of thermographic hot spots and sonographically identified perforators was 34.9 ± 22.2%. An increased matching rate of 62.2 ± 42.2% was noted taking only favored perforators (septocutaneous course, diameter >1 mm, distance <3 cm to the center, and visible concomitant veins) into account. Precooling with a fan followed by alcoholic disinfection provided clearest thermograms and fastest results.

CONCLUSION

 Thermographic imaging is a reliable method for perforator imaging. Its supplemental use to ultrasound may reduce examination time and yield additional information. Precooling by air flow or alcoholic disinfection can be easily implemented and provide the best thermograms. The matching rate of thermographic hot spots and perforators increases when taking only clinically relevant perforators into account. Thermal perforator mapping therefore reduces distraction by negligible perforators.

[Acute calcific periarthritis - a differential diagnosis of pyoarthrosis of the hand]

BACKGROUND

 The acute calcific periarthritis is caused by hydroxyapatite deposits in the periarticular soft tissue.The symptoms resemble a pyoarthrosis, explaining high rates of misdiagnosis.

PATIENTS

 Presented are the cases of a 45 and a 46 years old patient, who presented with acute onset of swelling, erythema, functional impairment and pain of the hand. Periarticular calcifications were identified radiologically.

RESULTS

 The symptoms completely resolved in both patients within few days under conservative treatment.

CONCLUSION

 The acute calcific periarthritis should be considered as a differential diagnosis of pyoarthrosis in the hand, especially if no suitable trauma preceeded. Usually conservative treatment with immobilization and antiphlogistic drugs rapidly leads to a complete remission.

Fully digital data processing during cardiovascular implantable electronic device follow-up in a high-volume tertiary center

Background

Increasing numbers of patients with cardiovascular implantable electronic devices (CIEDs) and limited follow-up capacities highlight unmet challenges in clinical electrophysiology. Integrated software (MediConnect^®) enabling fully digital processing of device interrogation data has been commercially developed to facilitate follow-up visits. We sought to assess feasibility of fully digital data processing (FDDP) during ambulatory device follow-up in a high-volume tertiary hospital to provide guidance for future users of FDDP software.

Methods

A total of 391 patients (mean age, 70 years) presenting to the outpatient department for routine device follow-up were analyzed (pacemaker, 44%; implantable cardioverter defibrillator, 39%; cardiac resynchronization therapy device, 16%).

Results

Quality of data transfer and follow-up duration were compared between digital (n = 265) and manual processing of device data (n = 126). Digital data import was successful, complete and correct in 82% of cases when early software versions were used. When using the most recent software version the rate of successful digital data import increased to 100%. Software-based import of interrogation data was complete and without failure in 97% of cases. The mean duration of a follow-up visit did not differ between the two groups (digital 18.7 min vs. manual data transfer 18.2 min).

Conclusions

FDDP software was successfully implemented into the ambulatory follow-up of patients with implanted pacemakers and defibrillators. Digital data import into electronic patient management software was feasible and supported the physician’s workflow. The total duration of follow-up visits comprising technical device interrogation and clinical actions was not affected in the present tertiary center outpatient cohort.

Development of a competency-based formative progress test with student-generated MCQs: Results from a multi-centre pilot study

Introduction: Progress tests provide students feedback on their level of proficiency over the course of their medical studies. Peer-assisted learning and competency-based education have become increasingly important in medical education. Although progress tests have been proven to be useful as a longitudinal feedback instrument, there are currently no progress tests that have been created in cooperation with students or that focus on competency in medical education.

In this study, we investigated the extent to which students can be included in the development of a progress test and demonstrated that aspects of knowledge related to competency can be represented on a competency-based progress test.

Methods: A two-dimensional blueprint for 144 multiple-choice questions (MCQs) covering groups of medical subjects and groups of competency areas was generated by three expert groups for developing the competency-based progress test. A total of 31 students from seven medical schools in Germany actively participated in this exercise. After completing an intensive and comprehensive training programme, the students generated and reviewed the test questions for the competency-based progress test using a separate platform of the ItemManagementSystem (IMS). This test was administered as a formative test to 469 students in a pilot study in November 2013 at eight medical schools in Germany. The scores were analysed for the overall test and differentiated according to the subject groups and competency areas.

Results: A pool of more than 200 MCQs was compiled by the students for pilot use, of which 118 student-generated MCQs were used in the progress test. University instructors supplemented this pool with 26 MCQs, which primarily addressed the area of scientific skills. The post-review showed that student-generated MCQs were of high quality with regard to test statistic criteria and content. Overall, the progress test displayed a very high reliability. When the academic years were compared, the progress test mapped out over the course of study not only by the overall test but also in terms of the subject groups and competency areas.

Outlook: Further development in cooperation with students will be continued. Focus will be on compiling additional questions and test formats that can represent competency at a higher skill level, such as key feature questions, situational judgement test questions and OSCE. In addition, the feedback formats will be successively expanded. The intention is also to offer the formative competency-based progress test online.

Electron theory of fast and ultrafast dissipative magnetization dynamics

For metallic magnets we review the experimental and electron-theoretical investigations of fast magnetization dynamics (on a timescale of ns to 100 ps) and of laser-pulse-induced ultrafast dynamics (few hundred fs). It is argued that for both situations the dominant contributions to the dissipative part of the dynamics arise from the excitation of electron-hole pairs and from the subsequent relaxation of these pairs by spin-dependent scattering processes, which transfer angular momentum to the lattice. By effective field theories (generalized breathing and bubbling Fermi-surface models) it is shown that the Gilbert equation of motion, which is often used to describe the fast dissipative magnetization dynamics, must be extended in several aspects. The basic assumptions of the Elliott-Yafet theory, which is often used to describe the ultrafast spin relaxation after laser-pulse irradiation, are discussed very critically. However, it is shown that for Ni this theory probably yields a value for the spin-relaxation time T(1) in good agreement with the experimental value. A relation between the quantity α characterizing the damping of the fast dynamics in simple situations and the time T(1) is derived.