A mini pig model for visualization of perforator flap by using angiography and MIMICS

A trial to visualize perforators images from CTA with a tablet device: experience of operating on minipigs

A reliable method for precise perforator mapping can be extremely valuable in perforator flap surgery. In this study, we attempted to map perforator location using 3-dimensional computed tomography angiography (CTA), a newly developed application, and a tablet device. Preliminary examinations to test the device were conducted in mini-pigs. We used 5 female mini-pigs. Preoperative imaging of the vasculature was undertaken with CTA in the prone position, following Iopamidol (200 ml) injection via the internal jugular vein. Prior to the examination, we placed round markers on the backs of the mini-pigs. To assess accuracy, we compared the perforator positions acquired with an optical position measurement device with the perforator positions acquired with the tablet device. Furthermore, we compared the perforator positions with the tablet navigation device, which we measured directly. We measured 12 perforators with the optical position measurement device. The mean difference was 10 mm (minimum, 2 mm; maximum, 20 mm). We measured these perforators with the tablet navigation device. The mean difference was 5.4 mm (minimum, 0 mm; maximum, 20 mm). The perforator flaps were elevated safely. The perforator flaps could be elevated safely using our device, as the mean difference was only 10 mm, which is acceptable for navigating perforator flap operations. Pig backs are triangular in shape; therefore, we were unable to place markers on the contralateral side. Thus, for clinical applications of the device, we should determine the ideal marker locations.

Anatomical differences in the abdominal wall between animal species with implications for the transversus abdominis plane block: a systematic review

PURPOSE

With the increased use of simulation-based training using animal models for the education of surgical and anaesthetic techniques, an increased understanding of the anatomy of such models and how they compare to humans is required. The transversus abdominis plane block is a regional anaesthetic technique that requires an understanding of the abdominal wall anatomy along with proficient ultrasound use. The current review aims to compare the anatomy of the abdominal wall across species, particularly focussing on the pertinent differences within the class of mammals, and secondarily, it aims to address the implications of these differences for the use of simulation-based training of the transversus abdominis plane block.

METHODS

To achieve this, the PubMed, Web of Science and Google Scholar databases were searched for relevant literature. Studies pertaining to the musculature, vasculature or innervation of the anterolateral abdominal wall across species were included.

RESULTS

The mammalian abdominal wall differs in its musculature, vasculature or innervation from that of amphibians, birds or reptiles; however, among species of mammals, the structure of the abdominal wall follows a similar framework. Particular differences among mammals include the additional muscular layer of the panniculus carnosus found in most mammals other than humans, the variable arterial origins and dominant vascular supply of the abdominal wall and the number of thoracolumbar nerves innervating the abdominal wall.

CONCLUSION

When using animal models for simulation-based training, the pig is recommended for the transversus abdominis plane block given its closely homologous abdominal wall structure, availability and larger comparative size.

Saphenous Artery Perforator Flaps in Minipigs: Anatomical Study and a New Experimental Model

This study describes the anatomy of the saphenous artery (SA) perforators in minipigs and the development of a new animal model. First, the anatomic characteristics of the SA and perforators in minipigs were examined after latex-lead oxide perfusion. Subsequently, the right hind limbs of 10 minipigs were used to generate capillary perforator flaps (group A; utilizing the SA and 5.5 cm of deep fascia above the knee), while all perforators of the left hind limbs were reserved (group B). Four additional minipigs were used to evaluate SA perforator flaps with capillary perforators plus sarcolemma and a small amount of muscle (group C). Preoperative and postoperative CTA of both hind limbs confirmed that all perforators were ligated in groups A and C. The average length of the SA was 14.86 ± 0.76 mm. The diameters of the SA at initiation, the medial tibial condyle, and the medial malleolus were 1.73 ± 0.15 mm, 1.50 ± 0.12 mm, and 1.30 ± 0.13 mm, respectively. There were 7.09 ± 1.16 perforators per hind limb, with an average diameter of 0.40 ± 0.13 mm (range, 0.10-0.78 mm), and the majority (96.2%) had a diameter >0.2 mm. The survival rates of the flaps in groups A, B, and C were 32 ± 39%, 100%, and 60.2 ± 17%, respectively. The position of the SA in minipigs is constant, its diameter is relatively large, and it has many perforators, allowing it to be used as a reliable model of perforator flaps, including capillary perforator flaps.

A Novel Perforator Flap Training Model Using a Chicken Leg

INTRODUCTION

Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg.

METHODS

A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised.

RESULTS

The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes.

CONCLUSION

This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training.

Effects of dietary protein/energy ratio on growth performance, carcass trait, meat quality, and plasma metabolites in pigs of different genotypes

BACKGROUND

The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes.

METHODS

Bama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups (Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment) in a 2 × 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases.

RESULTS

We observed significant interactions (P < 0.05) between breed and diet for total fat percentage, intramuscular fat (IMF) content, protein content in biceps femoris (BF) muscle, and plasma urea nitrogen (UN) concentration in the nursery phase; for average daily gain (ADG), average daily feed intake (ADFI), dry matter, IMF content in psoas major (PM) muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced (P < 0.05) growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher (P < 0.05) ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower (P < 0.05) feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN.

CONCLUSIONS

Compared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.

In vitro development of porcine transgenic nuclear-transferred embryos derived from newborn Guangxi Bama mini-pig kidney fibroblasts

Porcine transgenic cloning has potential applications for improving production traits and for biomedical research purposes. To produce a transgenic clone, kidney fibroblasts from a newborn Guangxi Bama mini-pig were isolated, cultured, and then transfected with red and green fluorescent protein genes using lipofectamine for nuclear transfer. The results of the present study show that the kidney fibroblasts exhibited excellent proliferative capacity and clone-like morphology, and were adequate for generation of somatic cell nuclear transfer (SCNT)-derived embryos, which was confirmed by their cleavage activity and blastocyst formation rate of 70.3% and 7.9%, respectively. Cells transfected with red fluorescent protein genes could be passed more than 35 times. Transgenic embryos cloned with fluorescent or blind enucleation methods were not significantly different with respect to cleavage rates (92.5% vs. 86.8%, p > 0.05) and blastocyst-morula rates (26.9% vs. 34.0%, p > 0.05), but were significantly different with respect to blastocyst rates (3.0% vs. 13.2%, p < 0.05). Cleavage (75.3%, 78.5% vs. 78.0%, p > 0.05), blastocyst (14.1%, 16.1% vs. 23.1%, p > 0.05) and morula/blastocyst rates (43.5%, 47.0% vs. 57.6%, p > 0.05) were not significantly different between the groups of transgenic cloned embryos, cloned embryos, and parthenogenetic embryos. This indicates that long-time screening by G418 caused no significant damage to kidney fibroblasts. Thus, kidney fibroblasts represent a promising new source for transgenic SCNT, and this work lays the foundation for the production of genetically transformed cloned Guangxi Bama mini-pigs.

Construction of a three-dimensional model of renal stones: comprehensive planning for percutaneous nephrolithotomy and assistance in surgery

OBJECTIVES

To construct a three-dimensional (3D) model of renal stones to facilitate comprehensive planning for percutaneous nephrolithotomy (PCNL) and to assist in surgery.

METHODS

Fifteen patients with complex renal stones, including one patient with a horseshoe kidney, eight patients with partial/complete staghorn, and six patients with multiple renal stones, participated in our study. Computed tomography images of the unenhanced, arterial, venous, and excretory phases were obtained before surgery. Image segmentation and 3D reconstruction of the renal stones were performed using Mimics 12.1 software. A virtual safe and reliable percutaneous renal access route were established for each patient by comprehensive planning based on the 3D model of renal stones. PCNL was subsequently performed with the assistance of the 3D model. Patient demographics, surgical details, and postoperative treatment parameters were recorded.

RESULTS

The 3D models of renal stones accurately represented the interrelationships between the intrarenal arteries and veins, collecting system, stones, and adjacent anatomical structures. PCNL was completed successfully in all 15 patients. The mean operating time was 75.6 ± 13.4 min. The change in hemoglobin concentration was 1.2 ± 0.3 g/l. The one-stage stone-free rate was 93.3%, and the final stone-free rate was 100%. No major postoperative complications were noted, except for postoperative pain in one case.

CONCLUSION

Construction of a 3D model of renal stones with the aim of minimizing the risks of percutaneous procedures and achieving higher one-stage stone-free rates is feasible for comprehensive PCNL planning and assistance in patients with complex renal stones.

Microvascular porcine model for the optimization of vascularized composite tissue transplantation

BACKGROUND

Devastating extremity injuries are prevalent but most often survivable on the modern battlefield. The complexity of these injuries requires advanced methods of reconstruction. This study is designed to validate the feasibility of gracilis myocutaneous flap transplantation via microvascular free tissue transfer in a porcine model. This model will facilitate study of autotransplant physiology as well as vascularized composite allotransplantation as an evolving method for reconstructing previously nonreconstructable injuries.

MATERIAL AND METHODS

A donor gracilis myocutaneous flap is procured from Yorkshire swine. The right external carotid artery and internal jugular vein are prepared as the recipient axis for microvascular anastomoses. Group 1 undergoes immediate microvascular anastomosis with resultant 1-h ischemic period. Group 2 undergoes delayed anastomosis with 3-h ischemic period. Markers of ischemia-reperfusion injury are evaluated after anastomosis and on postoperative days 1, 2, 7, and 14.

RESULTS

A novel porcine model for microvascular composite tissue transplantation is demonstrated. Ischemia period-dependent elevations in circulating biomarkers (lactate dehydrogenase [LDH], creatine kinase [CK], and aspartate transaminase [AST]) demonstrate the effects of prolonged ischemia. Both groups showed marked LDH elevation without significant statistical intergroup difference (P=0.250). The difference in CK and AST levels at 24h showed strong significance (P<0.0001).

CONCLUSIONS

A novel method of vascularized gracilis myocutaneous flap transplantation was validated in the Yorkshire swine. Assays for skeletal muscle tissue injury (LDH, CK, and AST) showed ischemia period-dependent response providing assessment of ischemia-reperfusion injury at the cellular level. Subsequent studies will evaluate agents that mitigate ischemia-reperfusion injury and transition these findings to potentiate vascularized composite allotransplantation.