Laparoscopic Ovariectomy in Mares Using a Polyamide Tie-Rap

Laparoscopic cryptorchidectomy using a resorbable self-locking loop device in dorsally recumbent horses

OBJECTIVE

To report the use and feasibility of a self-locking resorbable loop device for cryptorchidectomy.

STUDY DESIGN

Clinical prospective study.

POPULATION

Twenty horses.

METHODS

Horses suspected to have an abdominal testicle/s after admission work-up were enrolled. Horses were anesthetized in dorsal recumbency and a standard laparoscopic technique was performed. The looped device was inserted into the abdomen, glided around the testis/cord and tightened. Then, the spermatic cord was transected prior testis removal. Surgical procedure details and remarks, perioperative complications and total surgical time were recorded. Short- (>3 weeks) and long-term (>6 months) follow-ups were obtained by telephone questionnaire.

RESULTS

Median total surgical time was 67 min (range: 43-189 min) and significantly shortened after the first four horses. The loop device was easily glided around 13/20 abdominal testes and required more time and technical skills around larger testes (≥3 years). Excellent intraoperative hemostasis was achieved in 17 horses. Three horses demonstrated mild intraoperative bleeding that required retightening, device replacement or adding a second device, respectively. Three horses developed mild postoperative hemoabdomen identified ultrasonographically and were successfully managed medically. Follow-up revealed no significant complications related to the procedure. One horse was euthanized for colic 4 months after surgery and one died of hemolytic shock 17 months postoperatively.

CONCLUSION

This device represents another method to perform equine cryptorchidectomy that requires minimal training and laparoscopic expertise but demands knowledge of the device and application to prevent complications.

CLINICAL SIGNIFICANCE

Laparoscopic cryptorchidectomy using this device is an alternative technique for horses <3 years.

A preliminary investigation of the subcutaneous tissue reaction to a 3D printed polydioxanone device in horses

BACKGROUND

A 3D printed self-locking device made of polydioxanone (PDO) was developed to facilitate a standardized ligation technique. The subcutaneous tissue reaction to the device was evaluated after implantation in ten horses of mixed age, sex and breed and compared to loops of poly(lactic-co-glycolic acid) (PLGA). In two of the horses, the implants were removed before closing the skin. The appearance of the implants and surrounding tissue was followed over time using ultrasonography. Implants were removed after 10 and 27 (± 1) days for histologic examination.

RESULTS

On macroscopic inspection at day 10, the PDO-device was fragmented and the surrounding tissue was oedematous. On ultrasonographic examination, the device was seen as a hyperechoic structure with strong acoustic shadowing that could be detected 4 months post-implantation, but not at 7 months. Histology revealed a transient granulomatous inflammation, i.e., a foreign body reaction, which surrounded both PDO and PLGA implants. The type and intensity of the inflammation varied between individuals and tissue category.

CONCLUSIONS

The 3D printed PDO-device caused a transient inflammatory reaction in the subcutaneous tissue and complete resorption occurred between 4 and 7 months. Considering the intended use as a ligation device the early fragmentation warrants further adjustments of both material and the 3D printing process before the device can be used in a clinical setting.

Current Use of Equine Laparoscopy in Urogenital Disorders: A Scoping Review of the Literature from 2000 to 2021

(1) Background: Laparoscopic surgery replaced traditional invasive techniques for the treatment of common urogenital disorders in equids. The aim of this review is to evaluate applications and the development of urogenital laparoscopy from 2001 to 2021. (2) Methods: A scoping review of literature was undertaken according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines for scoping reviews on three databases (NCBI-PubMed, Web of Science-Thompson Reuters, and SciVerse Scopus). (3) Results: A total of 452 papers were identified. After duplicate removal and title screening, 181 papers underwent abstract screening. Of these, 160 + 10 papers (cited by others) were assessed for eligibility according to the PICOs. A total of 132 papers were considered eligible. Most of the research was focused on ovaries and testes, followed by urinary bladder and general articles about laparoscopy in horses. We identified 43 original studies (33%, RCT, NoRCT, and experimental trials), 39 case series/retrospective studies (29%), 37 case reports (28%), and 13 reviews (10%, narrative or systematic). (4) Conclusions: Gonadal disorders were the most investigated. Hand-Assisted Laparoscopic Surgery (HALS) and laparoscopic-assisted surgery represent valuable options for more challenging conditions (uterine and urinary bladder disorders).

Use of Polyamide (Nylon) Cable Ties for Vascular Ligation of Healthy Equine Jejunal Mesentery

Jejunal vascular ligation is an essential step in performing jejunojejunostomy. Hand sewn ligation is typically used and can increase operative time with long sections of bowel to be removed. Nylon cable ties (NCT) have been used for vascular ligation in horses but are yet to be investigated for application on the mesenteric vasculature of the gastrointestinal tract. Our objective was to evaluate the efficacy and short-term safety of NCT jejunal mesenteric vessel ligation in healthy horses. Eight healthy adult horses underwent midline celiotomy. A segment of jejunal mesentery was identified (≥4 arcades). Briefly, three fenestrations (proximal, middle, distal) were made 5–10 mm apart adjacent to the first and last vascular arcade to be ligated. Two sterilized NCT were passed to encircle the mesentery through the proximal and middle fenestrations, separated by intact mesentery. NCT were closed tightly and the vascular pedicle transected with Mayo scissors through the distal fenestration. Jejunojejunostomy was then performed and the mesentery sutured closed. The number of vascular arcades and time to ligate using NCT were recorded. At 2 weeks, horses underwent repeat celiotomy to assess the healing of the NCT ligation site and an equal number of vascular arcades were hand sewn double ligated using 2-0 Polyglactin 910 as a timed comparison. NCT mesenteric ligation was significantly faster than hand sewn methods (P < 0.01). Effective hemostasis was achieved in all cases. There was no evidence of local infection or adhesions at 14 days post-operatively. Further investigation in the long-term effects in horses as well as horses with strangulating jejunal lesions are needed for clinical application.

Use of Tubo-Ovarian Ligation Via Colpotomy as A Potential Method for Sterilization in Mares

The goal of this study was to develop a safe, effective, and economical method for permanent sterilization of mares based upon tubo-ovarian ligation performed via colpotomy. In this study, we evaluated the application of a nylon cable tie (zip-tie) to the ovarian pedicle and oviduct of mares to induce ovarian ischemia and tubal ligation without removal of ovaries. Initially, efficiency of zip-ties on the ovarian pedicle was tested in vitro and in vivo. Based on the absence of leakage through the zip-tie ligated vessels in anatomic specimens, we confirmed the potential efficacy of the technique. Next, ligation of the ovarian pedicle via a standing colpotomy was conducted in five mares. Although the surgical procedure in these mares appeared to be quick and efficient, all five mares were noted to develop ovarian adhesions to surrounding abdominal viscera in either one or both ovaries postoperatively. Ovarian ischemia led to loss of ovarian activity based upon ultrasound examination, which was confirmed by a low plasma progesterone concentration in four of the five mares. During the postoperative period, four mares demonstrated clinical signs related to the ovarian adhesions and were euthanized. The postoperative complications associated with ovarian adhesions to abdominal viscera presented significant challenges, limiting the success of this study. While this technique resulted in ovarian ischemia and atrophy in four out of the five mares, we were unable to assess long-term effects on the health and reproduction of the mares due to the ovarian adhesions to the surrounding tissues and the potential for secondary complications. Although technically feasible, tubo-ovarian ligation via colpotomy does not appear to be a viable option for sterilization of mares using the described technique due to ovarian adhesions post procedure.

In Vivo Versus In Vitro Degradation of a 3D Printed Resorbable Device for Ligation of Vascular Tissue in Horses

A resorbable 3D printed polydioxanone (PDO) device is manufactured to facilitate ligation of vascular tissue during surgery. The device must provide sufficient mechanical performance throughout the healing period. Therefore, degradation and mechanical performance of the device are investigated as a function of in vivo and in vitro aging. During aging the PDO device released cyclic and linear water-soluble products. In vivo aging resulted in higher relative number of linear oligomers in comparison to in vitro aging. A major loss of mechanical performance is observed after only 10 days in vivo and the Young's modulus (E) and tensile strength at break (σ_b ) decreased by 28% and 54%, respectively. This is in contrast to in vitro aging, where no loss of mechanical properties is observed during the same period. The in vivo aged devices exhibit clear holes in the matrices after 28 days, while apparent cracks are observed first after 140 days in vitro. These results highlight the sensitivity of the degradation process of resorbable devices with regards to the interactions of the device with the surrounding environment (tissues) and demonstrate the importance of in vivo testing as compliment to in vitro testing before clinical use of devices.

Use of polyamide cable ties during experimental omentectomy in adult horses with histopathological assessment

OBJECTIVE

To report the use of nylon cable ties (NCT) for omentectomy in the horse.

STUDY DESIGN

Experimental study.

ANIMALS

Eight healthy adult horses.

METHODS

Horses underwent nylon cable tie (NCT) ligation of the greater omentum after ventral midline celiotomy. The time required to complete the omentectomy was recorded. Horses were recovered for 14 days before repeat celiotomy, adhesions assessment, and histological examination of the omentectomy site using a proposed histologic grading scheme. The total time for omentectomy procedure and histologic score was assessed for normality. Data are expressed as mean ± standard deviation.

RESULTS

NCT ligation provided sufficient hemostasis to complete the omentectomy (28 ± 15 s), without rescue ligation. No gross evidence of intra-abdominal adhesion or morbidity was associated with the omentectomy site 14 days after surgery. NCT were intact at the site of application, covered with smooth fibrous connective tissue. Adiponecrosis with minimal inflammation and fibrovascular occlusion of omental vessels was present at the surgical site. Mild inflammation was present at the NCT-tissue interface.

CONCLUSION

The use of NCT resulted in fast and effective omentectomy in healthy horses without short-term evidence of inflammatory reaction or intra-abdominal adhesion.

CLINICAL SIGNIFICANCE

The described technique provides an alternative for omentectomy in healthy adult horses.

Effects of Leaving Amputated Ovaries Intra-Abdominally during Elective Bilateral Standing Laparoscopic Ovariectomy in Equids

Simple Summary

When removing the ovaries of a mare via laparoscopic technique, there is potential to drop the ovary in the abdomen when trying to exteriorize it through the abdominal wall. If the ovary can no longer be seen with the laparoscope, then the procedure is converted to a flank incision and the ovary is identified and removed by hand. Having to convert the procedure negates the benefits of the minimal invasive laparoscopic procedure and increases the risk of post-operative complications. The objective of this study was to identify if amputated ovaries left in the abdomen during surgery would atrophy or if they would regain a blood supply and produce hormones. After surgery, the mare’s hormone values were at low levels and an improvement in all mare’s behavior and general herd dynamics was observed. While this study does not encourage to leave ovaries in the abdomen after amputation, we report no complications related to their voluntary release into the abdomen.

Abstract

There is risk of dropping an amputated ovary within the abdomen during standing laparoscopic ovariectomies in mares. If the ovary can no longer be directly visualized with the laparoscope, the procedure is then converted to a flank laparotomy for manual retrieval of the ovary which negates the minimally invasive nature of the laparoscopic procedure. The objective was to identify if ovaries left in the abdomen after amputation would atrophy or if they re-vascularize. Standing bilateral ovariectomies were performed in mature mares, but after transection of the ovarian pedicle, the ovaries were intentionally dropped and left within the abdomen. Post-operative endocrine values were at basal levels and an improvement in all mare’s behavior and general herd dynamics was observed. While this study does not encourage to leave ovaries in the abdomen after amputation, we report no complication related to their voluntary release into the abdomen.

Left paralumbar fossa approach combined with mesocolon fenestration for bilateral equine ovariectomy

OBJECTIVE

To describe a standing left paralumbar fossa approach combined with mesocolon fenestration for bilateral equine ovariectomy.

STUDY DESIGN

Prospective experimental clinical study.

ANIMALS

Four healthy client-owned mares and 1 client-owned Molly mule.

METHODS

Mares were restrained in standing stocks and sedated with an α2 -agonist continuous infusion to effect. The abdominal cavity was approached via a left paralumbar fossa approach, and the contralateral right ovary was accessed through an incision in the mesocolon. The location of the window was adjusted to allow triangulation, adequate visualization, and manipulation of the contralateral right ovary. Each ovarian pedicle was ligated with extracorporeal ligatures prior to sharp transection. The ovaries were dropped and left within the abdomen as part of another study. The incision in the mesocolon was closed with laparoscopic staples. Mares were monitored hourly while hospitalized, and a questionnaire was completed by the owners 90 days after surgery.

RESULTS

Both ovarian pedicles were successfully ligated and transected in all mares through the left paralumbar fossa approach and mesocolon fenestration. The only complications consisted of mild incisional emphysema in 2 of 5 equids, with all resolving spontaneously. All equids returned to intended use at 90 days.

CONCLUSION

The left paralumbar fossa approach combined with mesocolon fenestration provided adequate access to both ovaries with minimal morbidity in this small population.

CLINICAL SIGNIFICANCE

A unilateral left paralumbar fossa approach and fenestration of the mesocolon should be considered as an alternative to traditional approaches for bilateral laparoscopic ovariectomies in equids.

Influence of caudal epidural analgesia on cortisol concentrations and pain-related behavioral responses in mares during and after ovariectomy via colpotomy

OBJECTIVE

To determine the influence of epidural detomidine and morphine on serum corticosteroid concentrations and pain-related behavioral responses in mares during and after ovariectomy via colpotomy.

STUDY DESIGN

Blinded prospective study.

ANIMALS

Nine university-owned mares.

METHODS

Five of 9 horses received caudal epidural detomidine hydrochloride (0.01 mg/kg) and morphine sulfate (0.1 mg/kg) prior to surgery. All horses received local anesthetic around the ovarian pedicle, 0.02 mg/kg butorphanol IV at the start of the procedure and after first ovary removal, were sedated as required throughout the procedure, and were monitored for leg lifting, grunting, and abdominal tensing. Horses were monitored hourly for pain postoperatively. Heart rate was recorded every 4 hours, and photographs were taken to assess pain according to the horse grimace scale (HGS). Control group horses (n = 4) were treated with butorphanol (0.02 mg/kg IV) every 4 hours for 24 hours postoperatively. All horses received oral phenylbutazone 18 hours postoperatively. Serum cortisol was measured prior to the procedure, after first and second ovary removal, and 8 and 24 hours postoperatively.

RESULTS

No differences were detected between horses receiving caudal epidural detomidine and morphine and those that received systemic opioids. A decrease in HGS score occurred after phenylbutazone administration.

CONCLUSION

Administration of caudal epidural detomidine and morphine resulted in similar pain-related behavior and corticosteroid concentrations as did administration of systemic butorphanol every 4 hours for 24 hours postoperatively.

CLINICAL SIGNIFICANCE

Caudal epidural detomidine and morphine may mitigate the requirement for frequent systemic opioid administration after a potentially painful procedure.

Degradation profile and preliminary clinical testing of a resorbable device for ligation of blood vessels

A resorbable device for ligation of blood vessels was developed and tested in vitro to reveal the degradation profile of the device and to predict the clinical performance in terms of adequate mechanical support during a healing period of 1week. In addition, preliminary clinical testing was performed that showed complete hemostasis and good tissue grip of renal arteries in five pigs. The device was made by injection molding of poly(glycolide-co-trimethylene carbonate) triblock copolymer, and it consisted of a case with a locking mechanism connected to a partly perforated flexible band. A hydrolytic degradation study was carried out for 7, 30 and 60days in water and buffer medium, following the changes in mass, water absorption, pH and mechanical properties. A new rapid matrix-free laser desorption ionization-mass spectrometry (LDI-MS) method was developed for direct screening of degradation products released into the degradation medium. The combination of LDI-MS and electrospray ionization-mass spectrometry analyses enabled the comparison of the degradation product patterns in water and buffer medium. The identified degradation products were rich in trimethylene carbonate units, indicating preferential hydrolysis of amorphous regions where trimethylene units are located. The crystallinity of the material was doubled after 60days of hydrolysis, additionally confirming the preferential hydrolysis of trimethylene carbonate units and the enrichment of glycolide units in the remaining solid matrix. The mechanical performance of the perforated band was followed for the first week of hydrolysis and the results suggest that sufficient strength is retained during the healing time of the blood vessels.

A review of equine laparoscopy

Minimally invasive surgery in the human was first identified in mid 900's. The procedure as is more commonly practiced now was first reported in 1912. There have been many advances and new techniques developed in the past 100 years. Equine laparoscopy, was first reported in the 1970's, and similarly has undergone much transformation in the last 40 years. It is now considered the standard of care in many surgical techniques such as cryptorchidectomy, ovariectomy, nephrosplenic space ablation, standing abdominal exploratory, and many other reproductive surgeries. This manuscript describes the history of minimally invasive surgery, and highlights many of the techniques that are currently performed in equine surgery. Special attention is given to instrumentation, ligating techniques, and the surgical principles of equine minimally invasive surgery.

A new resorbable device for ligation of blood vessels - A pilot study

BACKGROUND

During surgery, controlled haemostasis to prevent blood loss is vital for a successful outcome. It can be difficult to ligate vessels located deep in the abdomen. A device that is easy to use and enables secure ligatures could be beneficial. Cable ties made of nylon have been used for ligation but the non-resorbable material caused tissue reactions. The objective of this study was to use a resorbable material to construct a device with a self-locking mechanism and to test its mechanical strength and ligation efficiency.

METHODS

The device was manufactured by injection moulding of polydioxanone, a resorbable polymer used for suture materials. Polydioxanone with inherent viscosities of 1.9 dL/g and 1.3 dL/g were tested. The device consisted of a perforated flexible band which could be pulled through a case with a locking mechanism. After a first version of the device had been tested, some improvements were made. The locking case was downsized, corners were rounded off, the band was made thicker and the mould was redesigned to produce longer devices. Tensile tests were performed with the second version.The first version of the device was used to ligate the ovarian pedicle in a euthanized dog and to test echogenicity of the device with ultrasound. Compression of vessels of the ovarian pedicle was examined by histology. Both versions of the device were tested for haemostasis of and tissue grip on renal arteries in six anaesthetised pigs.

RESULTS

The tensile strength of the flexible band of the devices with inherent viscosity of 1.9 dL/g was 50.1 ± 5.5 N (range 35.2-62.9 N, n = 11) and the devices with inherent viscosity of 1.3 dL/g had a tensile strength of 39.8 ± 8.1 N (range 18.6-54.2 N, n = 11). Injection moulding of the polymer with lower inherent viscosity resulted in a longer flow distance.Both versions of the device had an effective tissue grip and complete haemostasis of renal arteries was verified. The device attached to the ovarian pedicle could be seen with ultrasound, and vessel compression and occlusion were verified by histology.

CONCLUSIONS

Tests of functionality of the device showed complete haemostasis and good tissue grip. Devices with a band of sufficient length were easily applied and tightened in tissue.

Laparoscopic ovariectomy in standing donkeys by using a new instrument

Bilateral laparoscopic ovariectomy was performed in six female donkeys. Laparoscopic ovariectomy was performed in standing position by using a new laparoscopic instrument which was developed by the authors. We used the instrument for isolation, coagulation and cutting of mesovarium. One laparoscope portal and two instrument portals were located in each paralumbar fossa. The ovary was removed through an enlarged second portal. The contralateral ovary was removed through the opposite paralumbar fossa. Hemostasis, coagulation and cutting of the mesovarium were achieved successfully using the new laparoscopic instrument. The time required for removal of each ovary was between 2 and 4 min (average 2.8 min). While the total time of unilateral ovariectomy was between 10 and 15 min (average 12 min). No additional ligature was required in all operations. There was no complication, hemorrhage or oozing of blood from the mesovarium during or after the operations. In conclusion, laparoscopic ovariectomy in donkeys by using this new instrument was safe and effective. The new instrument reduced the time of operation and provided a viable hemostasis and coagulation for blood vessels within the mesovarium. Also cutting of the mesovarium was very easy.