Laparoscopic nephrectomy in a porcine model

Videolaparoscopic prostatectomy in porcine model for training residents

Introduction:

Surgical training models prepare the resident for a more ethical surgical practice as well as providing a less steep learning curve. In urology, there are well-known models of pyeloplasty simulation, urethro-vesical anastomosis and nephrectomy, which have helped in the training of urology residents (1–3). Learning laparoscopic prostatectomy is a difficult surgery and requires advanced surgical skill from the surgeon (4), requires operate without a direct view of the surgical field in a two-dimensional space and with longer instruments (5).

Laparoscopic prostatectomy step by step makes the surgeon's learning curve less difficult, lead to less intraoperative complications, such as blood loss, while also enabling shorter operative time and less positive surgical margins (6).

The objective of surgical models is to simulate surgical procedures in a reliable way thus preparing the surgeon for his daily practice, surgical simulations in animal models have been described to compensate for inadequate clinical exposure (7).

The canine model of prostate cancer has many similarities with humans. Despite trying to develop a model that is as credible as possible, there are ethical issues in several countries, such as Brazil, that do not allow the use of live dogs for scientific experimentation and there is a difficulty in not standardizing the animals used (8, 9).

The swine surgical training model is widely known, accepted and used as a valuable tool in the teaching of new surgeons (10).

The porcine video laparoscopic prostatectomy model allows the urologist in training to exercise the skills required in a real surgical situation, practicing them in a single session (10). We will present an experimental model in pigs for training urology residents in laparoscopic radical prostatectomy with current techniques (11–13).

The limitations found are that the prostate has no limits as well defined as in humans, the urethra is long and coiled, the fat surrounding the pelvic organs is scarce and there is no postoperative follow-up for evaluating functionality after the procedure, as well as the effectiveness of the surgery with surgical margins. However, it is similar in surgical model presented, it is reproducible and can provide a realistic simulation environment to the beginner surgeon.

Material and Methods:

In this paper, according to the institutional protocol approved by the institutional ethics and research committee FMUSP n° 964/2017 and protocol was in accordance with current international regulations for the use of animals in Research: Reporting In Vivo Experiments (ARRIVE) guide. Ten male pigs weighing 20 to 22kg were used. The animals were anesthetized with a combination of Telazol (5mg/kg), Xylazine (1.5mg/kg), Cetamine (22mg/kg) and Atropine (0.04mg/kg) for orotracheal intubation followed by Isoflurane (2%). Animals were euthanized at the end of the procedure with a lethal dose of KCl (2mEq/kg). The trocar insertion points were marked using the epigastric vessels and umbilical region as reference points. Initially, urethral catheterization was performed using a hydrophilic Nitinol guidewire, followed by a perineal incision to dissect the tortuous urethra of the porcine model. A malleable urethral catheter 8Fr was inserted into their bladder. The animal was placed in the Trendelenburg position inserted and 12mm trocars were inserted in its umbilical region, utilizing 10mm in the surgeon's dominant hand, 5mm in his non-dominant hand of the surgeon, and 5mm in the first assistant's trocar.

The surgeon replicates the steps performed in a laparoscopic radical prostatectomy in humans, including the bladder catheterization, dissection of the anterior bladder plane, the vesicular and prostatic dissection, the suture of the dorsal venous plexus, a prostatectomy, an urethral vesical anast omosis, as well as the waterproof test, even including the performing of surgical steps using current concepts of anterior urethral suspension as the reconstruction of the posterior plane of the rhabdosphincter.

Results:

All steps of surgery could be reproduced in all ten porcine cases. No significant bleeding was observed and the surgical time was gradually reduced fifty percent from case one to last cases.

Conclusions:

The porcine model allowed the surgeon to replicate all the steps usually performed in a laparoscopic radical prostatectomy. The junior surgeons are better prepared to such difficult surgery. However, further studies will be necessary to prove the impact of the animal model presented in urological clinical practice.

Chicken and porcine models for training in laparoscopy and robotics

PURPOSE OF REVIEW

To review the most recent literature and contemporary role of the use of porcine and chicken models in laparoscopic and robotic simulation exercises, for training and skill assessment.

RECENT FINDINGS

There are multiple types of the simulators which include mechanical, virtual reality, hybrid simulators and animal models. The recent literature has seen insurgence of several of such simulators, specifically the animate ones comprising porcine and chicken models. The different training models reported have evolved from generalized and simpler, to a more task dedicated and complex versions. Unlike in the past, the recent publications include analysis of these models incorporating different measures of validity assessment.

SUMMARY

On account of the natural tissue properties inherent to these porcine and chicken models, they are proving to be instrumental in acquisition of higher surgical skills such as dissection, suturing and use of energy sources, all of which are required in real-time clinical scenarios be it laparoscopy or robotic-assisted procedures. In-vivo training in the animal model continues to be, perhaps, the most sophisticated training method before resorting to real-time surgery.

Laparoscopic animal surgery for training without sacrificing animals; introducing the rabbit as a model for infantile laparoscopy

INTRODUCTION

Improvement in laparoscopic skills requires practicing, and it is mostly beneficial when live animal models are considered for use. Apart from pelvic trainer, dogs and rabbits are used as the animal models for training laparoscopic surgeries at our center. Every effort is made to keep the animals alive after surgery.

MATERIALS AND METHODS

From January 2007 to January 2010, German shepherd dogs and Angora rabbits were selected as the animal models for laparoscopic skill training. Under general anesthesia, trainees performed several laparoscopic surgeries under the supervision of experienced surgeons.

RESULTS

A total number of 72 animals including 54 dogs and 18 rabbits were used for training laparoscopy. In total, some 107 different laparoscopic procedures were performed by trainees including nephrectomy, nephropexy, vesicotomy and vesicorrhaphy, vasectomies, spermatic cord ligation, and unilateral oophrectomy. There were one vascular and two visceral injuries in the rabbit model that were laparoscopically controlled, and conversion to open surgery happened in one case due to the failure in extracting the specimen from the abdominal cavity. Three visceral and six vascular injuries occurred in the canine model. Total mortality was five including three rabbits and two dogs.

CONCLUSIONS

The sacrifice of the animal is important to be avoided from both ethical and technical stand points. Dogs and rabbits are good models for laparoscopic training in urology, and it is possible to keep the animals alive after surgery by close monitoring. We also found the rabbit to be a good model for practicing infantile laparoscopic surgery, as it simulates the real surgery in this difficult age group.

Methods for laparoscopic training using animal models

To reduce the learning curves in humans, several training models have been developed for teaching laparoscopic surgery. The aim of various in vitro or in vivo training models is to help surgeons acquire basic laparoscopic skills such as hand-eye coordination, depth perception, and knot-tying, which should always be acquired prior to organ- or procedure-specific skills. Inexpensive video box trainers are best suited for this purpose. However, advanced laparoscopic skills, such as dissection, cutting, coagulation, and stitching, require more sophisticated animal or human cadaver models. The perfect training model should teach the skills required and should be inexpensive, universally available, and anatomically and physiologically identical to an anesthetized patient. In this paper, we review the different animal models for acquiring advanced laparoscopic skills and try to define their advantages and disadvantages.

Endoscopic approach for carotid artery surgery

BACKGROUND

Although recent advances in the treatment of carotid artery stenosis have included endovascular angioplasty and stent placement, carotid endarterectomy is still the approach of choice for carotid disease and is one of the most commonly performed operations today. Minimally invasive surgeries involving the neck have recently been performed for thyroid and parathyroid diseases. The purpose of this study was to evaluate the feasibility of an endoscopic approach for carotid artery surgery in a large animal model.

METHODS

Eight 25- to 30-kg pigs were used. Animals underwent endoscopic carotid dissection with carbon dioxide insufflation at 10 mmHg. A 1.5- to 2-cm arteriotomy was made in the common carotid artery. Four animals underwent direct arteriotomy closure, and four animals underwent synthetic patch graft placement using intracorporeal suturing techniques. Open examination of the operative site and carotid angiograms were performed at the end of the procedure. Operative time was recorded in the last four cases.

RESULTS

All animals tolerated the procedure well and carotid artery repair was successfully performed in all cases using a four-trocar technique. The entire extent of the cervical common and internal carotid arteries was exposed up to the cranial base. Cranial nerves and cervical structures were clearly visualized and preserved. No bleeding occurred at the end of the procedure. Carotid angiograms confirmed patent, nonstenotic vessels in all cases.

CONCLUSION

Endoscopic approach for carotid surgery is technically feasible in the porcine model. This approach may represent a valuable option for surgery of the carotid artery since it offers the advantages of minimally invasive techniques while maintaining the benefits of surgical arterial repair.

Minimally invasive spine surgery: an animal model for endoscopic approach to the anterior cervical and upper thoracic spine

BACKGROUND

Minimally invasive video-assisted techniques are currently used for thoracic and lumbar spine surgery with the aim of reducing the morbidity. Recently, an endoscopic approach has been used for endocrine neck surgery, with reduced pain and improved cosmetic results.

PURPOSE

To develop an animal model for an endoscopic neck approach to the anterior cervical and upper thoracic spine.

METHODS

Five pigs were used. A combination of one 5- and two 3-mm laparoscopic instruments was used to dissect the spine, and dedicated instrumentation was then used to perform discectomies. Carbon dioxide was insufflated at 10 mm Hg. Dissection was carried out upward and downward on the anterior aspect of the spine; discectomy was performed at various levels and evaluated at autopsy.

RESULTS

All pigs tolerated the procedure well. Visibility of the cervical spine was excellent, and exposure from C1 to T3 was obtained. For discectomy, an additional 10-mm trocar was inserted, and discectomy of C3-C4 and C4-C5 was performed. Proper location and adequacy were confirmed at autopsy.

CONCLUSION

The endoscopic neck approach allows exposure of the entire cervical spine and the upper thoracic spine in the porcine model. This approach has the potential to reduce the morbidity associated with the open cervical approach and provides a wider view and exposure than conventional open surgery. The availability of the porcine model allows the acquisition of the necessary technical skills before introducing this advanced procedure in humans.

Hydro-jet dissection for laparoscopic nephrectomy: a new technique

OBJECTIVES

The Hydro-Jet technique has been used to cut various industrial materials. In the medical field, this technique has been successfully used for selective dissection of the parenchyma of organs such as the liver. Recently, this technique was successfully used for laparoscopic cholecystectomy in humans. We developed a new Hydro-Jet probe and a technique of Hydro-Jet dissection during laparoscopic nephrectomy (LN) in a porcine model and compared the results with those of conventional laparoscopy.

METHODS

Fourteen pigs underwent unilateral LN using the Hydro-Jet and a conventional LN on the contralateral side. A Muritz 1000 Hydro-Jet generator was used. An adjustable water pressure gauge allowed manual control up to a maximum of 30 atm, and coagulation was applied by way of a bipolar thermoapplicator. The bent end of the probe allowed both blunt dissection and concomitant high-pressure water application. Results were compared with regard to ease of anatomic dissection, complications, and operative time between the two techniques.

RESULTS

LN was successful in all animals with no conversion to open surgery. The dissector allowed anatomic planes to be created in a relatively bloodless field, and continuous water flow allowed a clear view for the operator. The high-pressure stream resulted in excellent dissection of adventitial and soft tissue adjacent to vascular structures, with complete preservation of vessels and ureter for selective ligation. The dissection time was shortened (mean 27 minutes for the Hydro-Jet versus 40 minutes for the conventional technique).

CONCLUSIONS

To our knowledge, we describe the first report of Hydro-Jet dissection for LN as an alternative to the conventional technique. The improved anatomic dissection may decrease complications. Moreover, shorter operating times were achieved, which may result in cost savings. Further studies in humans are necessary to investigate this technique.

Common laparoscopic procedures in swine: a review

Swine serve as excellent models for many laparoscopic procedures. As more operations are being performed laparoscopically, it is essential for the surgeon to have a good understanding of laparoscopic techniques. This manuscript reviews some commonly performed laparoscopic operations with an emphasis on models in swine. Porcine anatomy is generally similar to human anatomy with some minor differences. Practice on porcine models can help refine techniques and increase efficiency and skill.

A porcine model for laparoscopic adrenalectomy

Laparoscopic adrenalectomy has been successfully performed and described in humans. Though it is presently not widely employed it offers tremendous potential for adrenal surgery. It remains, however, an advanced technique requiring demonstration and practice. The aim of this study is to develop a porcine model of adrenalectomy for teaching and advancing the technique applicable to human surgery. Five female pigs weighing 10-20 kg underwent bilateral adrenalectomy by the lateral approach using endotracheal intubation. The left adrenal was resected with the pig in the right decubitus position. The animal was repositioned to left decubitus and the right adrenal was resected. In each case four 10-mm trochars were placed over the respective flanks. There was no need to mobilize the colon or liver (in the pig model). The peritoneum over each gland was incised and the gland dissected in a cephalocaudal manner. The vessels were ligated and divided particularly those from the vena cava. Upon completion blood loss (< 100 cc) and operating times (mean 60 min for the left and 90 min for the right) were assessed and the animal was sacrificed. The glands were weighed (mean 1.23 g R and 1.15 g L) and measured. Using this model, experience is gained in positioning the subject as well as trocars, in fine dissection in a lateral orientation, and in techniques of hemostasis. Although porcine and human adrenal anatomy differ in some details the pig constitutes an excellent model for the development of the technical experience required to perform adrenalectomy in humans.