Endogenous adipose tissue as a hemostatic: use in microsurgery

Investigation of Autologous Fat Transfer in Capsule Formation around Silicone Implants in a Rat Model

BACKGROUND

In this experimental study, the authors investigated whether fat placement in the pocket during implant insertion affects capsule formation.

METHODS

Twenty albino Wistar rats, 400 g each, were used. The rats were divided into two groups, A and B, of 10 rats each. At the dorsum of each rat, four pockets (2 × 2 cm each) were dissected, two left and two right of the midline. In each pocket, a 1 × 1 × 1.5-cm silicone implant was inserted. In the two left pockets, only silicone implants were placed (control). In the two right pockets, 0.4 ml of fat was injected around the implant. Animals in group A were killed 2 months postoperatively, and those in group B were killed 4 months postoperatively. The implants were dissected with the capsule and sent for histopathologic examination.

RESULTS

The data of the fat transfer group was compared with control in groups A and B. Capsule thickness, neovascularization, myofibroblast layer thickness, and mast cell population demonstrated no statistically significant difference in either group A (p = 0.385, p = 0.862, p = 0.874, and p = 0.210, respectively) or group B (p = 0.338, p = 1.000, p = 0.288, and p = 0.344, respectively). Inflammation was statistically significantly less (p = 0.07) at 4 months (group B) in the fat transfer group compared to the control group. Likewise, cellularity was statistically significantly less (p = 0.019) at 4 months for the fat transfer group compared with the control group.

CONCLUSION

Fat injection in the pocket during implant placement may reduce inflammation and cellularity of capsules and predispose to faster capsule maturation.

CLINICAL RELEVANCE STATEMENT

PLEASE PROVIDE 1- TO 2-SENTENCE STATEMENT.

Errores ergonómicos en un curso básico de entrenamiento en microcirugía

Introducción. La implementación de la ergonomía en microcirugía minimiza las posiciones forzadas que causan dolor y molestias, las cuales están asociadas a errores en la técnica.Objetivo. Determinar los errores ergonómicos en microcirugía para caracterizar la relación entre las malas posturas y el dolor en diferentes zonas del cuerpo.Materiales y métodos. Estudio de tipo observacional que incluyó 71 estudiantes de un curso básico de microcirugía. Se utilizaron dos formatos de evaluación ergonómica: en el primero, el instructor registraba el desempeño del estudiante en cada ejercicio y, en el segundo, el estudiante evaluaba la presencia de molestias físicas por medio de una escala de dolor. Por último, se determinó la relación entre la posición ergonómica y la presencia de dolor.Resultados. Se observó un desempeño regular en la posición de pies (57%); de brazos y antebrazos (17%); de espalda (17%), y de cabeza y cuello (5.7%). El 25.3% reportó dolor en la región lumbar; el 19.7%, en la zona de músculo trapecio; el 18.5%, en el cuello; el 14%, en las manos, y el 8.5%, en otras zonas del cuerpo no especificadas. Se evidenció desorganización del instrumental en el 45.8% de los casos.Conclusiones. Las malas posiciones observadas en los participantes se relacionaron con molestias y dolor en las zonas lumbar y del músculo trapecio. Las posturas incorrectas de cabeza, cuello y brazos generaron molestias en la zona de hombros y espalda, mientras que las posiciones erradas de piernas y pies sensibilizaron la región lumbar.

The Benefits of Expert Instruction in Microsurgery Courses

BACKGROUND

 Microsurgery requires repeated practice and training to achieve proficiency, and there are a variety of curriculums available. This study aims to determine the importance of an expert instructor to guide students through procedures. We compared student proficiency across two microsurgery courses: one with (Columbia University, United States [CU] cohort) and one without a dedicated microsurgery instructor (University of Thessaloniki, Greece [UT] cohort).

METHODS

 Students were divided into two cohorts of 22 students (UT cohort) and 25 students (CU cohort). Student progress was evaluated by examining patency (lift-up and milking tests), anastomotic timing, and quality (Anastomosis Lapse Index [ALI]) of end-to-end arterial and venous anastomoses on day 1 and again on day 5. Chi-squared tests evaluated patency immediately and 30 minutes postoperation. t-Tests evaluated anastomotic timing and ALI scores. p-Values < 0.05 were considered significant.

RESULTS

 We evaluated progress within and between each cohort. Within the CU cohort, the quality of the arterial and venous anastomosis improved, respectively (by 54%, p = 0.0059 and by 43%, p = 0.0027), the patency of both the arterial and venous anastomosis improved, respectively (by 44%, p = 0.0002 and by 40%, p = 0.0019), and timing of arterial and venous anastomosis reduced respectively (by 36%, p = 0.0002 and by 33%, p = 0.0010). The UT cohort improved the quality of their arterial anastomoses (by 29%, p = 0.0312). The UT cohort did not demonstrate significant improvement in the other above-mentioned parameters. The CU cohort improved materially over the UT cohort across categories of quality, patency, and timing.

CONCLUSION

 There are clear benefits of an expert instructor when examining the rate of progress and proficiency level attained at the conclusion of the course. We suggest students who are seeking to maximize proficiency in microsurgical procedures enroll in courses with an expert instructor.

Generation, Endothelialization, and Microsurgical Suture Anastomosis of Strong 1-mm-Diameter Collagen Tubes

Tissue-engineered vascular grafts that are based on reconstituted extracellular matrices have been plagued by weak mechanical strength that prevents handling or anastomosis to native vessels. In this study, we devise a method for making dense, suturable collagen tubular constructs of diameter ≤1 mm for potential microsurgical applications, by dehydrating tubes of native rat tail type I collagen and crosslinking them with 20 mM genipin. Crosslinked dense collagen tubes with 1 mm inner diameter yielded ultimate tensile strength of 342 ± 15 gF and burst pressure of 1313 ± 156 mm Hg, comparable to the strength of a rat femoral artery, and supported endothelial cell adhesion and growth. End-to-end anastomosis of 0.5-mm-diameter tubes to explanted arteries displayed anastomotic strength of 82 ± 21 gF, which is sufficient for surgical applications. In vivo implantation of cell-free tubes as interpositional grafts in the rat femoral circulation yielded stable anastomosis with blood flow for 20 min. Seeded dense collagen tubes represent a promising alternative to venous graft that can potentially be used to bridge between short artery stubs in replantation surgeries.

The rat model in microsurgery education: classical exercises and new horizons

Microsurgery is a precise surgical skill that requires an extensive training period and the supervision of expert instructors. The classical training schemes in microsurgery have started with multiday experimental courses on the rat model. These courses have offered a low threat supervised high fidelity laboratory setting in which students can steadily and rapidly progress. This simulated environment allows students to make and recognise mistakes in microsurgery techniques and thus shifts any related risks of the early training period from the operating room to the lab. To achieve a high level of skill acquisition before beginning clinical practice, students are trained on a comprehensive set of exercises the rat model can uniquely provide, with progressive complexity as competency improves. This paper presents the utility of the classical rat model in three of the earliest microsurgery training centres and the new prospects that this versatile and expansive training model offers.