Transvaginal Mesh Insertion in the Ovine Model

Summary

This protocol describes mesh implantation in the ovine rectovaginal septum using a single vaginal incision technique, with and without the trocar-guided insertion of anchoring arms.

Abstract

This protocol describes mesh insertion into the rectovaginal septum in sheep using a single vaginal incision technique, with and without the trocar-guided insertion of anchoring arms. Parous sheep underwent the dissection of the rectovaginal septum, followed by the insertion of an implant with or without four anchoring arms, both designed to fit the ovine anatomy. The anchoring arms were put in place using a trocar and an "outside-in" technique. The cranial arms were passed through the obturator, gracilis, and adductor magnus muscles. The caudal arms were fixed near the sacrotuberous ligament, through the coccygeus muscles. This technique allows for the mimicking of surgical procedures performed in women suffering from pelvic organ prolapse. The anatomical spaces and elements are easily identified. The most critical part of the procedure is the insertion of the cranial trocar, which can easily penetrate the peritoneal cavity or the surrounding pelvic organs. This can be avoided by a more extensive retroperitoneal dissection and by guiding the trocar more laterally. This approach is designed only for experimental testing of novel implants in large animal models, as trocar-guided insertion is currently not used clinically.

Introduction

Pelvic organ prolapse is clinically diagnosed in half of women who had at least one vaginal delivery, but subjectively, it bothers half of women overall¹. The mainstay of therapy is surgical reconstruction using either native tissue or implant materials, but each of these methods has its limitations, including recurrence or local complications^2,3,4. The ideal implant has not yet been identified; hence, there is an ongoing demand for product innovation and for the development of a proper pipeline for preclinical experimentation prior to the introduction....

Protocol

Ethical approval for this experiment was obtained from the Ethics Committee on Animal Experimentation of the KU Leuven (P065/2013). Animals were treated in accordance with current national guidelines on animal welfare.

1. Material and the Experimental Animal

1. Surgery preparation
   1. In the surgical theater cover a table with a sterile drape and prepare one sterile curved trocar (Figure 1, panel A), sterile surgical instruments, sutures, and sterile gauze. Perform the entire surgical procedure in sterile conditions if the experiment includes follow-up. Place all instruments on the table to be ready for use dur....

Results

Management in a Longer Observation Setup

Following the surgical procedure, vaginal packing (a saline-solution-soaked gauze package inserted in the vagina immediately after the surgery) may be inserted for 24 h to secure the implant position. The sheep should be placed in a recovery cage and its respiratory function followed until full recovery. Later, it is possible to place the sheep in the stable and to allow .......

Discussion

Here, we describe an experimental procedure in sheep, aimed to mimic vaginal dissection and transvaginal mesh insertion of an implant with or without anchoring arms. The subsequent steps and instruments were inspired by surgical procedures done for POP and stress urinary incontinence^15,16,19,20. After initial anatomical dissections, there were still some problems during experimental mesh insert.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Animals:
parous female sheep (45 - 65 kg)	Zoötechnical Institute of the KU Leuven	NA	experimetnal animal
Sterile clothing:
sterile drape 45 x 75 cm	Lohmann & Rauscher, Regensdorf, Germany	33002	other material
sterile OR drape 150 x 180 cm	Lohmann & Rauscher, Regensdorf, Germany	33009	other material
sterile glowes 2x	Lohmann & Rauscher, Regensdorf, Germany	16652	other material
sterile surgical gown 2x	Lohmann & Rauscher, Regensdorf, Germany	19342	other material
surgical head cap 2x	Lohmann & Rauscher, Regensdorf, Germany	17427	other material
surgical face mask 2x	Lohmann & Rauscher, Regensdorf, Germany	11983	other material
Other surgical material
implant	FEG Textiltechnik GmbH, Aachen, Germany	NA	purposely designed implant
3/0 polypropylene suture	Prolene, Ethicon, Diegem, Belgium	8762H	suture material
3/0 polygecaprone suture	Vicryl, Ethicon	J311H	suture material
gauze swabs 10 x 10 cm 10x, 12-ply	Lohmann & Rauscher, Regensdorf, Germany	11574	other material
syringe 10 mL	Becton Dickinsosn S.A., Madrid, Spain	300613	aqua-dissection
needle 16 gauge	Terumo, Leuven, Belgium	NN-2238R	aqua-dissection
Surgical equipment:
blade no.22	Fine science isntruments, Heidelberg, Germany	10022-00	surgical instruments
Allis tissue forceps 1x	Fine science isntruments, Heidelberg, Germany	11091-15	surgical instruments
Standart pattern forceps 1 x 2 theeth 1x	Fine science isntruments, Heidelberg, Germany	11023-14	surgical instruments
Standart pattern forceps straight serrated 1x	Fine science isntruments, Heidelberg, Germany	11000-14	surgical instruments
Scalpel handle 1x	Fine science isntruments, Heidelberg, Germany	10004-13	surgical instruments
Halstead-Mosquito forceps 2x	Fine science isntruments, Heidelberg, Germany	13008-12	surgical instruments
Standart pattern scissors 1x	Fine science isntruments, Heidelberg, Germany	14001-14	surgical instruments
Metzenbaum scissors 1x	Fine science isntruments, Heidelberg, Germany	14016-18	surgical instruments
Crile Wood needle holder 1x	Fine science isntruments, Heidelberg, Germany	12003-15	surgical instruments
Kell forceps 1x	Fine science isntruments, Heidelberg, Germany	13018-14	surgical instruments
Long Starr Self-Retaining Retractor with eight 5 mm sharp stay hooks	Cooper Surgical, Tumbull, USA	3704	surgical instruments
Heaney Simon Vaginal Retractor	Medical supplies & equipments co., Katy, Texas, USA	403-129FSI	surgical instruments
Trocar (Insnare)	Bard, West Sussex, United Kingdom	NA	any trocar on market for transvaginal mesh implantation
Medication:
amoxilicilline clavulanate 1000 mg / 300 mL (Ampiciline)	GSK, Wavre, Belgium	NA	antibiotics
buprenorfin 0.3 mg/mL + chlorocresol 1.35 mg/mL (Vetregesic)	Ecuphar, Oostkamp, Belgium	NA	analgesia
ketamin HCL 100 mg/mL (Ketamine 1000)	Ceva Sante Animale, Brussels, Belgium	NA	anesthesia
isoflurane (IsoFlo)	Abbott Laboratories Ltd, Maidenhead, Berkshire, UK	NA	anesthesia
polyvidone iodium 7.5% (Braunol)	B. Braun Medical, Machelen, Belgium	NA	local desinfection
saline solution 500 mL	B. Braun Medical, Machelen, Belgium	NA	aqua-dissection
Xxylazine HCl , 1 mL/50 kg	Vexylan, Ceva Sante Animale, Belgium	NA	premedication
atropine Sulfate 15 mg/mL (),	Viatris, Belgium	NA	premedication