A novel self-gripping long-term resorbable mesh providing temporary support for open primary ventral and incisional hernia

A novel synthetic fully long-term resorbable self-gripping mesh has been recently developed to reinforce soft tissue where weakness exists during ventral hernia repair open procedures. This resorbable mesh is a macroporous, knitted, poly-L-lactide, poly-trimethylene carbonate copolymer monofilament mesh with the ProGrip™ technology, providing grips on one side of the mesh. A new poly-L-lactide, poly-trimethylene copolymer was developed to provide the required features for mechanical support during at least 20 weeks covering the critical healing period, including resistance to fatigue under cyclic loading conditions, as it occurs in patients. The yarns and mesh initial physical and biomechanical properties were characterized. Then, the mesh mechanical strength was evaluated over time. The mechanical properties of the proposed mesh were found to be above the generally recognized threshold value to mechanically support the repair site of a hernia over a 20-week period during in-vitro cyclic loading test. The mesh performance was evaluated in vivo using a published preclinical porcine model of hernia repair at 4-, 12- and 20-weeks post implantation. The burst strength of the hernia repair sites reinforced with the new mesh were higher at 4 & 12 weeks and comparable at 20 weeks to the one of the native abdominal walls. At all time points, the mesh was well tolerated with moderate inflammation and was fast integrated in the abdominal wall at 4 weeks. Particularly, the grips were nicely engulfed in the newly formed connective tissue. They must facilitate the anchoring of the mesh by their extension from the mesh and their mushroom shape. The preclinical data of the self-gripping resorbable mesh suggests that it has all the favorable characteristics for future clinical use during ventral hernia repair open procedures.

OC-070 A NOVEL SELF-GRIPPING LONG-TERM RESORBABLE MESH PROVIDING TEMPORARY SUPPORT FOR PRIMARY VENTRAL AND INCISIONAL HERNIA

Medtronic recently developed a novel synthetic fully long-term resorbable self-gripping mesh to reinforce soft tissue where weakness exists during ventral hernia repair procedures. This resorbable mesh is a macroporous, knitted, poly-L-lactide, poly-trimethylene carbonate copolymer monofilament mesh with the ProGrip™ technology.

The biocompatibility profile of the mesh has been extensively established and documented. No systemic nor local adverse reactions have been observed from implantation to complete resorption and metabolization of the mesh in a subcutaneous implantation preclinical rabbit model.

Its performance was evaluated at 20 weeks using a modified published preclinical porcine model of hernia repair (Martin, 2013; Deeken, 2013). Histologic examination of the implantation sites confirmed that this novel mesh was well tolerated and led to new extracellular collagen matrix formation. The burst strength of the hernia repair sites reinforced with the new mesh was statistically equivalent to the one of the native abdominal walls.

Currently marketed ProGrip™ meshes have been clinically and successfully used with less mechanical fixation devices than non-self-gripping meshes (Chastan, 2009; Rangwani, 2021). The new self-gripping long-term resorbable mesh fixation performance was demonstrated to be statistically equivalent to the one of ProGrip™ Self-Gripping Polyester Mesh both in ex-vivo testing and in an in vivo porcine model. This should support the ease-of-use feature of the mesh with a limited need for additional mechanical fixation, which will likely be associated with a shorter surgical time.

The preclinical tests of the self-gripping resorbable mesh are compelling enough to make it a new mesh candidate for future clinical use.

Standing laparoscopic abdominal lavage using a suction-irrigation device in 2 horses with primary suppurative peritonitis

The use of a laparoscopic suction-irrigation device in 2 standing horses for lavage of the abdomen for the treatment of primary suppurative peritonitis is reported. Two horses were presented with a 1- to 2-week history of weight loss. Abdominocentesis revealed highly elevated total nucleated cell count. Peritoneal lavage systems were placed in both horses, but complications prevented adequate lavage. Both horses underwent standing laparoscopy; the dorsal abdomen was explored and the abdomen was profusely lavaged, using a suction-irrigation device. The procedure was efficient and allowed adequate visualization of the dorsal abdomen and lavage. A successful outcome was achieved in both cases. Key clinical message: Lavage of the abdomen of horses with peritonitis can be achieved under standing sedation, using a laparoscopic technique. In appropriately selected cases, this allows for adequate visualization of the dorsal abdomen and efficacious abdominal lavage.

The Used Electrocautery Loop in the Equine Proximal Phalanx

An 18-month-old 420 kg Standardbred colt was admitted for removal of three type I proximal plantar osteochondral fragments of the proximal phalanx. An electrocautery loop probe was used for the arthroscopic removal of the osteochondral fragments. Distension of the metatarsophalangeal joints was achieved using a 1.5% glycine solution. Under arthroscopic guidance, the soft tissue attachments of the osteochondral fragments were transected with the electrocautery loop probe. Once freed of all soft tissue attachments, the fragments were removed with a Ferris-Smith intervertebral disc rongeur. The electrocautery loop probe permitted an easy, precise and smooth dissection of intra-articular soft-tissue structures. Six weeks after the operation, the colt had returned to training. After eight months, the colt remained sound and was racing. The loop electrocautery probe was used as an alternative to manual sharp instruments in the arthroscopic treatment of Type I proximal plantar osteochondral fragments of the proximal phalanx.

An electrocautery loop probe was used in the arthroscopic treatment of type I proximal plantar osteochondral fragments of the proximal hind phalanx in a Standardbred horse. The loop electrocautery probe was used as an alternative to manual sharp instruments.

Biomechanical and computational evaluation of two loading transfer concepts for pancarpal arthrodesis in dogs

OBJECTIVE

To evaluate 2 plate designs for pancarpal arthrodesis and their effects on load transfer to the respective bones as well as to develop a computational model with directed input from the biomechanical testing of the 2 constructs.

SAMPLE

Both forelimbs from the cadaver of an adult castrated male Golden Retriever.

PROCEDURES

CT imaging was performed on the forelimb pair. Each forelimb was subsequently instrumented with a hybrid dynamic compression plate or a castless pancarpal arthrodesis plate. Biomechanical testing was performed. The forelimbs were statically loaded in the elastic range and then cyclically loaded to failure. Finite element (FE) modeling was used to compare the 2 plate designs with respect to bone and implant stress distribution and magnitude when loaded.

RESULTS

Cyclic loading to failure elicited failure patterns similar to those observed clinically. The mean ± SD error between computational and experimental strain was < 15% ± 13% at the maximum loads applied during static elastic loading. The highest bone stresses were at the distal extent of the metacarpal bones at the level of the screw holes with both plates; however, the compression plate resulted in slightly greater stresses than did the arthrodesis plate. Both models also revealed an increase in bone stress at the proximal screw position in the radius. The highest plate stress was identified at the level of the radiocarpal bone, and an increased screw stress (junction of screw head with shaft) was identified at both the most proximal and distal ends of the plates.

CONCLUSIONS AND CLINICAL RELEVANCE

The FE model successfully approximated the biomechanical characteristics of an ex vivo pancarpal plate construct for comparison of the effects of application of different plate designs.

Finite element analysis of a novel pin-sleeve system for external fixation of distal limb fractures in horses

The transfixation pin cast (TPC) is an external skeletal fixation technique used to treat horses with distal limb fractures, but its use is often associated with pin-loosening and an increased risk of treatment failure. To address implant loosening, the pin sleeve cast system (PSC) was recently designed and consists of a pin-sleeve unit inserted into the bone. Each pin runs through a sleeve placed in the bone, making contact at two fixed points only within the sleeve. Each pin is attached to a ring embedded in a resin cast. In this report, the mechanical performance of a traditional TPC pin arrangement was compared with that of the PSC using validated finite element models of bone substitutes previously tested in vitro. The PSC resulted in a marked reduction in peak strain magnitude around the pins and a more even distribution of strain across the bone cortex. The two systems resulted in comparable proximal fragment displacement and had a similar stress concentration around bone defects during implant removal. The findings suggest that the PSC load transfer mechanism is effective even in geometrically complex structures like equine bones.

Adaptive response of equine intestinal Na+/glucose co-transporter (SGLT1) to an increase in dietary soluble carbohydrate

Experimental and epidemiological evidence suggests that consumption of hydrolyzable carbohydrate, hCHO (grain), by horses is an important risk factor for colic, a common cause of equine mortality. It is unknown whether the small intestinal capacity to digest hCHO and/or to absorb monosaccharides is limiting, or even if horses can adapt to increased carbohydrate load. We investigated changes in the brush-border membrane carbohydrate digestive enzymes and glucose absorptive capacity of horse small intestine in response to increased hCHO. Expression of the Na(+)/glucose co-transporter, SGLT1, was assessed by Western blotting, immunohistochemistry, Northern blotting, QPCR, and Na(+)-dependent D-glucose transport. Glucose transport rates, SGLT1 protein, and mRNA expression were all 2-fold higher in the jejunum and 3- to 5-fold higher in the ileum of horses maintained on a hCHO-enriched diet compared to pasture forage. Activity of the disaccharidases was unaltered by diet. In a well-controlled study, we determined SGLT1 expression in the duodenal and ileal biopsies of horses switched, gradually over a 2-month period, from low (<1.0 g/kg bwt/day) to high hCHO (6.0 g/kg bwt/day) diets of known composition. We show that SGLT1 expression is enhanced, with time, 2-fold in the duodenum and 3.3-fold in the ileum. The study has important implications for dietary management of the horse.

Ventral laparoscopic abomasopexy on adult cows

Displacement of the abomasum is frequently diagnosed by veterinarians in bovine practice and numerous surgical techniques have been developed to treat and prevent this condition. Complications secondary to those techniques are related to their degree of invasiveness and the development of postoperative wound infections. The objectives of this study were to describe a safe and reliable abomasopexy technique by laparoscopy and to assess postoperative adhesion formation. A ventral laparoscopic abomasopexy was performed on 10 adult dry cows. The abomasum was fixed with 4 simple interrupted sutures using USP 2 polydioxanone suture material. No major complications were encountered during the surgery. Abomasal adhesions were visually evaluated by laparoscopy 3 mo postoperatively. This technique proved to be simple and safe, and it provided adequate abomasum fixation in healthy dry cows. It could be used to surgically correct left displaced abomasum.

General principles of laparoscopy

Laparoscopic surgery is minimally invasive and minimally traumatic in cattle. It allows the animal to return rapidly to production. These techniques are destined to develop further, especially in the dairy and show cattle industries, where recovery periods must be as short as possible. Although it is important to remain skeptical about new procedures if they do not offer advantages over open techniques, in many cases laparoscopy is clearly superior. Laparoscopy is not an easy surgical technique. It requires a good knowledge of anatomy and abdominal topography and rigorous training. It must be performed with great care and delicacy because complications, such as perforated organs, can occur. Laparoscopy also requires the use of sophisticated and costly technology.

Arthroscopic Removal of Axial Osteochondral Fragments of the Proximoplantar Aspect of the Proximal Phalanx Using Electrocautery Probes in 23 Standardbred Racehorses

OBJECTIVES

To describe the outcome after arthroscopic electrosurgical excision of axial osteochondral (OC) fragments of the proximal plantar aspect of the 1st phalanx (P1) in horses.

STUDY DESIGN

Retrospective study.

POPULATION

Twenty-three Standardbred racehorses.

METHODS

Medical records of Standardbred racehorses that had arthroscopic dissection of axial OC fragments of the proximal plantar aspect of P1 with electrocautery probes were reviewed. Horses were positioned in dorsal recumbency; a 1.5% glycine solution was used to maintain joint distension. The arthroscope portal was in the proximal plantar joint pouch and OC fragments were approached using either an ipsilateral or a contralateral triangulation technique. Dissection of the fibrous attachments was performed using loop and hook electrocautery probes. Follow-up was obtained by telephone questionnaire of owners or trainers and examination of race summary records.

RESULTS

Thirty-three axial OC fragments were removed from 28 metatarsophalangeal joints (left, 14; right, 14). No major operative or postoperative complications occurred. Seven of 8 (79%) of horses that raced before surgery raced after surgery. Thirty-six percent (n=4) of horses that had not raced before surgery raced after surgery.

CONCLUSION

Intra-articular electrosurgery is a safe, easy alternative to conventional excision of axial OC fragments of the proximal plantar aspect of P1.

CLINICAL RELEVANCE

Arthroscopic excision using electrocautery probes is a valid alternate method for removal of axial OC fragments of the proximal plantar aspect of P1. In addition, the dorsal recumbency position facilitates removal of several fragments and multiple joint surgery.

Intraosseous Gentamicin Perfusion of the Distal Metacarpus in Standing Horses

OBJECTIVE

To report tissue gentamicin concentrations after intraosseous (IO) perfusion in standing horses.

STUDY DESIGN

In vivo study.

ANIMALS OR SAMPLE POPULATION

Twelve horses.

METHODS

Sedated horses had a cannulated cortical bone screw inserted into the dorsolateral aspect of the treated metacarpus and a tourniquet applied proximally. Gentamicin (2.2 mg/kg) diluted in sterile saline solution (0.1 mL/kg) was infused through the screw. Two horses were euthanatized at each time interval: 0, 2, 6, 12, 24, and 36 hours. Synovial fluid and bone samples were collected distal to the screw from both forelimbs. Gentamicin concentrations were measured using fluorescence polarization immunoassay.

RESULTS

The highest synovial fluid gentamicin concentrations were 385+/-273 microg/mL (mean+/-SD) in the metacarpophalangeal joint, 225+/-205 microg/mL in the proximal interphalangeal joint, 215+/-205 microg/mL in the distal interphalangeal joint, 382+/-195 microg/mL in the digital flexor tendon sheath, and 206+/-161 microg/mL in the navicular bursa. The highest bone concentrations of gentamicin were 55+/-30 microg/g in the distal metacarpus, 34+/-27 microg/g in the proximal, 16+/-15 microg/g in the middle, and 16+/-2.2 microg/g in the distal phalanges, and 27+/-17 microg/g in the proximal and 24+/-11 microg/g in the distal sesamoid bones.

CONCLUSION

Standing IO perfusion of gentamicin resulted in local antibiotic concentrations in the synovial structures and bones of the distal aspect of the limb that exceed the reported minimum inhibitory concentration of pathogens commonly implicated in equine orthopedic infections.

CLINICAL RELEVANCE

Standing IO perfusion of gentamicin in the distal aspect of the limb should be considered for treatment of orthopedic infections of this region in horses.

Use of an endoscopic suturing device for laparoscopic resection of the apex of the bladder and umbilical structures in normal neonatal calves

OBJECTIVE

To develop a laparoscopic technique using an endoscopic suturing device for the resection of the apex of the bladder and the umbilical structures in large-animal neonates. Study Design-Experimental study. Animals or Sample Population-Seven healthy male Holstein calves.

METHODS

A laparoscopic technique for resection of the apex of the bladder was developed on 2 calf cadavers, then evaluated on 5 anesthetized calves. The calves were positioned in dorsal recumbency, and 4 ventral abdominal portals were used. The umbilical vessels were double-ligated using an endoscopic suturing device and subsequently transected. The apex of the bladder was transected between a row of laparoscopic clips applied near the apex and atraumatic laparoscopic forceps applied distally; then, the edges were apposed using an endoscopic suturing device. The dissected umbilical remnants were removed from the abdomen through a small incision centered at the umbilicus. One month later, the calves were euthanatized and a second-look laparoscopy performed; then, bladders were collected for gross and histologic examination.

RESULTS

No major complications occurred during or after surgery. The endoscopic suturing device permitted both effective ligation of the umbilical vessels and closure of the bladder. During second-look laparoscopy, healing of the peritoneal surface of the bladder and umbilical vessels was assessed to be excellent in 4 calves. A focal adhesion of omentum to the bladder suture line was observed in 1 calf. Focal adhesions of the omentum to the umbilical incision site occurred in 2 calves. The bladder mucosa was completely healed at the surgical sites.

CONCLUSION AND CLINICAL RELEVANCE

Resection of the apex of the bladder and umbilical vessels in calves can be accomplished laparoscopically using an endoscopic suturing device.

Use of synovial fluid markers of cartilage synthesis and turnover to study effects of repeated intra-articular administration of methylprednisolone acetate on articular cartilage in vivo

In vivo the effects of intra-articular (IA) corticosteroids on articular cartilage remain controversial. This study was designed to examine this issue using synovial fluid (SF) markers of cartilage metabolism. Paired radiocarpal joints, without clinical or radiographic signs of joint disease, were studied in 10 adult horses. Aseptic arthrocentesis was performed weekly for 13 weeks. IA injections of methylprednisolone acetate (MPA) into the treatment joint and the vehicle into the control joint were performed at weeks 3, 5 and 7. We used radioimmunoassays on SF samples which measure a keratan sulfate epitope (KS) and the 846 epitope on cartilage aggrecan (PG) and the C-propeptide (CPII) of cartilage type II procollagen which is released following synthesis of this molecule. Gel chromatography was performed on selected SF samples to evaluate the sizes of SF PG molecules. The total joint KS and the 846 epitopes were both present on a heterogeneous population of mainly molecules which, from chromotographic analysis, appeared to be mainly fragments of the articular cartilage aggrecan. They were significantly elevated in MPA joints whereas CPII was significantly reduced compared to the control during the treatment period. These results indicate that the repeated use of IA MPA leads to a potentially harmful inhibition of procollagen II synthesis and an increased release of degradation products of the PG aggrecan from articular cartilage.

Alterations in cartilage type-II procollagen and aggrecan contents in synovial fluid in equine osteochondrosis

The etiology and pathophysiology of osteochondrosis remain poorly understood because it is difficult to obtain material from lesions in the early stage of this disease and because there is no satisfactory experimental animal model. We wished to determine whether there are changes in articular cartilage turnover in equine osteochondrosis, which closely resembles the human disease, by assaying cartilage matrix molecules in synovial fluids. We used immunoassays that measure a keratan sulfate epitope and the epitope 846 on the cartilage proteoglycan aggrecan and the C-propeptide of cartilage type-II procollagen, which is released following the synthesis of this molecule, to analyse synovial fluids from equine tarsocrural joints with and without osteochondrosis. In young horses with osteochondrosis, there was a significant increase of C-propeptide of type-II procollagen accompanied by a decrease in the 846 and keratan sulfate epitopes. The results identify differential alterations in aggrecan and type-II collagen turnover in the cartilage matrix in young animals with osteochondrosis that may contribute to the pathological degeneration of articular cartilage in this disease.

Use of electrocautery probes in arthroscopic removal of apical sesamoid fracture fragments in 18 Standardbred horses

OBJECTIVE

To develop a technique for arthroscopic excision of apical sesamoid fracture fragments using electrocautery probes.

ANIMALS OR SAMPLE POPULATION

A total of 18 Standardbred horses.

METHODS

Arthroscopic removal of apical sesamoid fracture fragments using both hook and loop electrocautery probes was performed on 18 Standardbred horses. The fracture fragments were approached using either an ipsilateral (3) or contralateral (15) arthroscopic triangulation technique. Distension of the metacarpo- (metatarso)-phalangeal joints was achieved using a 1.5% glycine solution. Under arthroscopic guidance, both the suspensory and intersesamoidean ligament attachments to the abaxial and the axial margins of the apical fragment were transected using a hook electrocautery probe. Subsequently, the palmar (plantar) soft tissue attachments to the apical fragment were transected with a loop electrocautery probe. Once freed of soft tissue attachments, the apical fragment was removed with Ferris-Smith intervertebral disc rongeur. The arthroscopic portals were closed in a routine manner.

RESULTS

Horse ages ranged from 2 to 8 years (median, 2.5 years). Eighteen apical sesamoid fracture fragments were removed from the left (8) and right (8) hind limbs and the left (1) and right (1) forelimbs. Apical fragments occured in 15 lateral and 3 medial proximal sesamoid bones. No major complications occurred during or after surgery. The electrocautery probes permitted an easy and precise dissection of all soft tissue attachments to the apical sesamoid fracture fragments in all horses. Follow-up time was 7 to 44 months (median, 26 months); 10 of 14 horses returned to racing. Seven of nine horses that raced before surgery raced again and three of five that had not raced before surgery, raced afterwards.

CONCLUSION

Arthroscopic excision of apical sesamoid fracture fragments can be accomplished arthroscopically using electrocautery probes.

CLINICAL RELEVANCE

Arthroscopic electrosurgery is an efficient and safe alternative for intra-articular dissection in horses.

Use of laparoscopic equipment to divide abdominal adhesions in a filly

Exploratory laparoscopy of the right dorsal portion of the abdominal cavity was performed on a Standardbred filly because of signs of mild abdominal pain of 7 days' duration. On the basis of clinical examination, diagnosis was suppurative peritonitis, abdominal adhesions in the area of the right ovary, and right displacement and impaction of the pelvic flexure of the ascending colon. During laparoscopy, an abdominal adhesion between the right uterine horn, the cecum, and the pelvic flexure was identified. The abdominal adhesions were either stretched with laparoscopic forceps used as a probe or dissected bluntly with the tips of a pair of 10-mm laparoscopic Kelly forceps. Antibiotics were administered for 21 days after surgery. The horse fully recovered and raced 11 months after the surgery.

Paralumbar fossa laparoscopic ovariectomy in horses with use of Endoloop ligatures

OBJECTIVE

The purposes of this study were to develop a technique of paralumbar fossa laparoscopic ovariectomy using Endoloop ligatures and to avoid a laparotomy incision for ovary removal by using a 33-mm diameter muscle spreader trocar-cannula unit.

ANIMALS OR SAMPLE POPULATION

Seven mares.

METHODS

Bilateral laparoscopic ovariectomy was performed under general anesthesia in two horses and under neuroleptanalgesia and local anesthesia in five standing mares. Ovaries were approached from the ipsilateral paralumbar fossa through two portal sites located in the paralumbar fossa and a third between the 17th and 18th ribs. Insufflation of the abdominal cavity was achieved using an automatic carbon dioxide insufflator. Two Endoloop ligatures were placed on the mesovarium. The cannula, located in the center of the paralumbar fossa, was removed, and a 33-mm diameter trocar-cannula unit, with a cone-shaped muscle spreader extremity, was inserted through the same portal. The mesovarium was transected between the ovary and the ligatures. The ovaries were removed from the abdomen through the 33-mm diameter cannula. The abdominal wall was closed in a routine manner.

RESULTS

No major complications occurred during or after surgery.

CONCLUSION

Paralumbar fossa laparoscopic ovariectomy in mares using Endoloop ligatures and the 33-mm diameter trocar-cannula unit was an effective technique for ovariectomy of normal ovaries in this study.

CLINICAL RELEVANCE

Endoloop ligatures provide a viable alternative for laparoscopic ligation of ovarian pedicles in mares.

Laparoscopic abdominal anatomy of foals positioned in dorsal recumbency

Eleven foals (nine cadavers and two anesthetized) positioned in dorsal recumbency were examined to describe normal abdominal anatomy viewed by laparoscopy. The foals ages ranged from 1 to 150 days. Insertion sites were selected for a Verres needle, laparoscope and instrument portals to avoid trauma to the umbilical structures. The abdominal cavity was insufflated to a pressure of 10 to 12 mm Hg using an automatic carbon dioxide insufflator. Laparoscopic examination allowed excellent observation of the umbilical structures, the bladder, the genital tract, the inguinal area, the liver and segments of the intestinal tract in all foals. However, the duodenum and ileum were not identified. An embryonic vestige of the yolk stalk (ductus pedunculi vitellini) was identified in six foals. In four foals, this appeared as a fibrous band extending from the umbilicus to the cranial abdominal cavity where it inserted on the small intestine. In two foals only the fibrous umbilical portion of the band was observed.