Comparison of suturing models: the effect on perception of basic surgical skills

BACKGROUND

Acquisition of Basic Surgical Skills (BSS) are essential for medical students. The objective was to determine it's fidelity impact.

METHODS

Using four suturing models (SM) (pigskin, sponge, commercial pad, and orange), SM-quality and student-SM interaction were evaluated. After a 1-h class, participants were divided into groups and randomly assigned exercises in SM in 15-min intervals. The experiment included completing three individual simple stitches and a 3-stitch continuous suture in each SM.

RESULTS

Eighty-two medical students participated. Suturing quality was better in pigskin and sponge, which were also the preferred models (p < 0.001). Significant differences in quality between the insertion and exit point, and firmness of knots (p < 0.05) in both simple and continuous sutures, as well as between length and distance in continuous ones (p < 0.001) were identified.

CONCLUSIONS

Acquisition and quality of BSS are influenced by the intrinsic characteristics of SM. An adequate degree of resistance, consistency, and elasticity are necessary.

Schwann Cell Precursor Transplant in a Rat Spinal Cord Injury Model

Background

Differentiation of mesenchymal stem cells into Schwann cell precursors could reverse established lesions and sequelae of medullary transection.

Objective

The objective of this study was to study the clinical response of mesenchymal stem cell transplantation with Schwann precursor cell transplantation in a rat spinal cord injury model, using motor function and histopathologic studies.

Materials and Methods

A total of 28 Sprague-Dawley rats were randomly divided among four groups (n = 7 in each): sham group, control group, mesenchymal stem cell transplant group, and Schwann cell precursor transplant group. The surgical procedure was a laminectomy with transection of the spinal cord at the T11 level in the transplant groups and the injury control group. After 1 week, the transplant groups received stem cells directly in the injury site. Hind limb motor function was assessed using the locomotive scale of Basso, Beattie, and Bresnahan. 1 month after transplantation, all specimens were sacrificed to make a histopathologic description of sections taken from the site of injury and where stem cells were transplanted. Mean scores of mobility were compared using analysis of variance (ANOVA) of one factor with 95% reliability between groups and ANOVA of repetitive measures to evaluate evolution in the same group.

Results

We observed that the control group had statistically greater mobility than the other groups (p < 0.0001) and that the group with spinal injury without treatment had the lowest mean mobility. The mobility score values from the Schwann cell precursor group were statistically higher than the group treated with mesenchymal stem cells (p < 0.0001).

Conclusion

Schwann precursor cells had a greater effect on locomotive function than mesenchymal stem cells.

Dermatology Surgery Training in a Live Animal Model

Background Surgical technique is an important part of resident training, which is the reason why various models have been implemented to acquire this skill. Animal models have been useful in teaching dermatologic suturing techniques. With the advancements in technology, simulators have been developed for these exercises, but at a very high cost. The use of pig heads and freshly killed animals have proven to be effective and low-cost. However, they do not reproduce skin pathologies with accuracy.

Objective To evaluate the effectiveness of a live anesthetized rat model to simulate skin pathologies requiring surgical excision in a dermatologic suture workshop for residents.

Methods We analyze the outcome of a theoretical and practical suturing workshop using live Wistar rats with 13 dermatology residents.

Results The residents showed an improvement in surgical maneuvers, suturing techniques, and in the use of surgical instruments (p < 0.01).

Conclusion The model proposed in the present study was economic, easy to obtain and to manage, and it portrays live and accurate skin response to manipulation. Therefore, it is effective for conducting surgical training sessions in dermatology.

Human Umbilical Vessels: Choosing the Optimal Decellularization Method

There is an increasing demand of small-diameter vascular grafts for treatment of circulatory pathologies. Decellularization offers the possibility of using human blood vessels as scaffolds to create vascular grafts. Umbilical vessels have great potential because of their availability and morphological characteristics. Various decellularization techniques have been used in umbilical vessels, but consensus on which is the most appropriate has not yet been reached. The objective of this review is to analyze the morphological and biomechanical characteristics of decellularized human umbilical arteries and veins with different techniques. Evidence indicates that the umbilical vessels are a viable option to develop small-diameter vascular grafts. Detergents are the agents most often used and with most evidence. However, further studies are needed to accurately analyze the components of the extracellular matrix and biomechanical characteristics, as well as the capacity for recellularization and in vivo functionality.

[Study of peripheral nerve injury in trauma patients]

OBJECTIVE

To determine the prevalence, location, mechanism, and characteristics of peripheral nerve injury (PNI) in trauma patients.

MATERIAL AND METHODS

A retrospective study of medical records with PNI diagnosis secondary to trauma in the period of 2008-2012. The following information was collected: gender, age, occupation, anatomic location, affected nerve, mechanism of injury, degree of injury, costs, and hospitalization time.

RESULTS

The prevalence of PNI is 1.12%. The location of the nerve injury was 61% upper limb, the highest incidence was presented to the brachial plexus (35%) and ulnar nerve (18%). The mechanism of the lesion was sharp injury (19%).

DISCUSSION

The PNI are commonly present in people of a productive age. Neurotmesis was the most frequent degree of lesion. The patients stayed at hospital 2.51 ± 1.29 days and the average cost was 12,474.00 Mexican pesos ± 5,595.69 (US$ 1,007.54 ± 452.21) for one nerve injury.