Minimally invasive microsurgical decompression of an intervertebral disc protrusion in a dog.

OBJECTIVE: To report the successful treatment of intervertebral disc protrusion with minimally invasive microsurgery in a large breed dog. STUDY DESIGN: Retrospective case report. ANIMAL: A 4-year-old, neutered male, German shepherd dog presented with chronic progressive ambulatory paraparesis and thoracolumbar pain; lumbar intervertebral disc protrusion and severe spinal cord compression at L2-L3 were diagnosed. METHODS: A minimally invasive approach was used to access the target surgical area by using a muscle splitting technique and retractors. Intraoperative fluoroscopy confirmed correct placement. Magnification and illumination through a surgical microscope were used (microsurgery) to perform the spinal cord decompression by means of a foraminotomy and lateral corpectomy. RESULTS: Technically, the combination of fluoroscopy and muscle splitting approach offered adequate minimally invasive access. Microsurgery allowed for precise and efficient spinal cord decompression. Clinically, no immediate postoperative neurological deterioration was observed. Opioid usage was limited to 24 hours postoperatively. Focal muscle swelling was observed postoperatively for 2 days, and hospital stay was 3 days. At 7 weeks postoperatively, neurological examination results were normal, and postoperative MRI confirmed spinal cord decompression. No complications were reported. CONCLUSION: The procedure was associated with a small incision, limited muscle trauma, early improvement of the neurological status, a short hospital stay, and limited postoperative pain. CLINICAL SIGNIFICANCE: This case provides evidence that minimally invasive microsurgery is an effective treatment for intervertebral disc protrusion in large breed dogs and may offer benefits regarding postoperative pain and functional recovery.

Transverse and vertical incisions affect the viability of in vitro-produced embryos submitted to a simplified microsurgery approach.

Integrating in vitro embryo production with embryonic microsurgery facilitates the generation of monozygotic twins. However, despite their potential benefits, these methods have not been widely adopted in commercial settings because of their substantial costs. Hence, there is a need to streamline the bisection procedure while ensuring efficient production of viable demi-embryos. In this study, we investigated the impact of different orientations of microsurgical incisions in relation to inner cell mass on embryonic development, morphology, viability, and expression of cell fate protein markers using a simplified microsurgery approach. Ovaries were transported from the slaughterhouse to the laboratory and aspirated to obtain oocytes that were selected and subjected to in vitro embryo production. The selected expanded blastocysts (n = 204) underwent microsurgery. The blastocysts were immobilized to facilitate incision using an adapted microblade, yielding demi-embryos (vertical incision) and viable embryonic fragments (transverse incision). The structures were then re-cultured for 12 h. Viability was assessed by measuring the re-expansion rate after re-culture, followed by immunofluorescence analysis of proteins (CDX2 and NANOG) and apoptosis analysis using terminal deoxynucleotyl transferase dUTP nick end-labeling (TUNEL). Microsurgically derived embryos exhibited remarkable plasticity, as evidenced by a slight reduction (P < 0.05) in the re-expansion rate (transverse 64.2 % and vertical 57.2 %) compared to that of the control group (blastocysts without microsurgery) (86.7 %). They also demonstrated the ability of morphological reconstitution after culturing. Despite the anticipated decrease (P < 0.05) in the total number of cells and embryo volume, microsurgery did not result in a significant increase (P > 0.05) in the number of apoptotic cells. Furthermore, microsurgery led to higher (P < 0.05) expression of markers associated with pluripotency, indicating its efficiency in preserving regenerative capacity. Moreover, microsurgery, whether followed by immunosurgery or not, made the isolation of embryonic cells easier. In conclusion, both transverse and vertical microsurgery incisions enabled the production of identical demi-embryos and served as tools for isolating embryonic cells without compromising the resumption of development and the apoptotic index.

Comparison of surgical invasiveness between micro-endoscopic discectomy/microscopic discectomy and conventional hemilaminectomy in dogs.

Micro-endoscopic discectomy (MED) or microscopic discectomy (MD) have been performed for disc herniation in humans. The purpose of this study was to compare the invasiveness of the hemilaminectomy in dogs between the approach using a cylindrical retractor for the MED/MD and a conventional open surgical approaches in dogs. First, as preliminary studies, we analyzed the suitability of the cylindrical retractor for the vertebral body of small to medium-sized dogs on the X-ray computed tomographic images using the three-dimensional analysis software, and confirmed that it was possible to open a bone window of an approximate length of 1.72 clto the spinal canal with the cylindrical retractor with a diameter 17 mm using two medium-sized canine cadavers. Next, to determine difference in the invasiveness of hemilaminectomy, the magnitude of tissue damage, surgical stress and postoperative pain were compared between the conventional open approach (hemilaminectomy group: HL group, n=6) and the surgical approach using the cylindrical retractor (MD group, n=6) in 12 beagle dogs. The plasma creatine phosphokinase, C-reactive protein and cortisol concentrations, incision length and University of Melbourne Pain Scale scores after the hemilaminectomy were significantly lower in the MD group than in the HL group. There were no significant differences between the durations of surgery and the other evaluated indices. The approach using the MD can provide a less invasive hemilaminectomy than the conventional approach in dogs.

A jugular bleeding technique in rabbits.

When studying pharmacokinetics in rabbits, researchers must often take multiple blood samples from conscious rabbits. Researchers usually collect these samples via the auricular vein, typically through a port or an indwelling catheter. The authors have developed an easy and efficient alternative method for obtaining multiple blood samples from conscious rabbits via the external jugular vein. This jugular bleeding technique serves as a refinement to blood sampling methods that require rabbits to undergo surgery (e.g., to insert a port) because it requires no alleviation of pain. During a 2-year period, the authors have taken multiple blood samples from more than 400 rabbits and have seen no adverse events attributed to this procedure.

Characterization of a rodent model for the study of arterial microanastomoses with size discrepancy (small-to-large).

Microsurgical autotransplantation of tissues is employed clinically to reconstruct defects following burns, trauma and surgical cancer ablation, and to correct congenital abnormalities. Transplant vessels of <3 mm are anastomosed by hand under the microscope. Experimentally, anastomotic patency rates decrease with increasing vessel diameter mismatch, and clinically, ratios of 3:1 or greater lead to unacceptably low arterial patency rates. A number of surgical techniques for dealing with size mismatch are described, but no one method has found favour, and few controlled studies of technique are reported. In this report, a rodent superficial caudal epigastric artery (SCEA)/femoral artery (FA) model for the study of these techniques is described in detail. The diameter ratio between these vessels lies in the clinically relevant range of 1:1.5-1:2.5. In the male Wistar rat, external vessel diameters were not found to increase markedly in size between animal weights of 300 and 500 g. The length of FA distal to the origin of the SCEA, which is important in allowing undisturbed distal run-off, was found to be negatively associated with animal body weight, implying that a smaller animal would be better for this model. Mean femoral arterial flow rate, measured by transit-time ultrasound, was noted to be statistically and physiologically significantly higher in the right artery when compared with the left. This model has advantages over interposition vein graft models in that it minimizes vessel compliance mismatch, and avoids the need for a second anastomosis.

Surgical treatment of an elbow hygroma utilizing microvascular free muscle transfer in a newfoundland.

Microvascular free muscle transfer utilizing the rectus abdominis muscle, in combination with a mesh skin graft and transarticular external fixator, were used following the surgical excision of an elbow hygroma in a Newfoundland dog. Postoperatively, the dog did well with minimal complications and has yet to have a recurrence 10 months following surgery. This report describes the utility and successful use of the rectus abdominis free tissue transfer in the surgical correction of a difficult elbow hygroma in the dog.

Microsurgical arterial anastomosis in young and adult rats: an evolutive and comparative study

Purpose: To evaluate the caliber of an arterial micro-anastomosis in the young growing animal using a continuous suture technique. Additionally, late morphological changes and blood flows distal to the anastomosis were evaluated. Methods: Seventy-four Wistar rats were submitted to laparotomy to access the aorta for blood flow measurement. The aorta was sectioned using microsurgery technique and an end-to-end anastomosis with continuous suture. After a period of six months to one year, the anastomosis was checked. Results: Regarding the size of the aortas, comparing the pre- and postoperative values, there was an increase of 13.33% in adult animals and 25% in young animals, without any difference in the blood flows. Conclusions: The arteries of young rats show signs of growth at the site of the anastomosis performed with continuous suture.

Urethral prolapse corrected by microsurgery in a cat: a case report.

Urethral prolapse is a rare condition in dogs and cats. A 7-month-old male cat presented with intermittent penile bleeding and a red mass protruding from the tip of the penis. Urethral prolapse was diagnosed by using a surgical microcamera to examine the genital area. Urethroplasty and preputial advancement surgery were performed using a surgical microscope, to successfully correct the urethral prolapse.

Anatomical description of the extratemporal facial nerve under high-definition system: a microsurgical study in rats

Purpose: To describe the microsurgical anatomical aspects of the extratemporal facial nerve of Wistar rats under a high-definition video system. Methods: Ten male Wistar rats (12­15 weeks old), without veterinary diseases, weighing 220­280 g, were used in this study. All animals in this study were submitted to the same protocol and by the same surgeon. A 10-mm incision was made below the bony prominence of the right or left ear, and extended towards the angle of the mandible. The dissection was performed and the main branches of the facial nerve were dissected. Results: The main trunk of the facial nerve has a length of 0.88 ± 0.10 mm and a length of 3.81 ± 1.03 mm, measured from its emergence from the stylomastoid foramen to its bifurcation. Seven branches originating from the facial nerve were identified: posterior auricular, posterior cervical, cervical, mandibular, buccal, temporal, and zygomatic. Conclusions: The anatomy of the facial nerve is comparable to that of humans, with some variations. The most observed anatomical division was the distribution in posterior auricular, posterior cervical, cervical, mandibular, buccal, temporal, and zygomatic branches. There is no statistical difference between the thickness and distance of the structures compared to the contralateral side.

Preliminary tests of a new reversible male contraceptive in bush dog, Speothos venaticus: open-ended vasectomy and microscopic reversal.

Open-ended vasectomies were performed on four male bush dogs (Speothos venaticus), with three having microscopic reversal surgery (vasovasostomy) between 10 and 20 mo post-vasectomy. The key to ease of reversal is leaving the distal (testicular) end open to allow leakage, resulting in a pressure-relieving granuloma. The proximal (abdominal) end is cauterized, providing an effective seal. This technique prevents the buildup of pressure in the epididymis, therefore limiting damage to the male's reproductive capacity. Described here are detailed procedures for both surgeries. One of the three males that underwent vasovasostomy has successfully impregnated his female partner. This study demonstrates that these techniques can be successfully applied to animals. With the two remaining pairs, none of the four individuals were proven breeders prior to the study, so it is not possible to eliminate the possibility of previously existing infertility. This technique may have limited application for carnivores, because vasectomy does not prevent potential adverse effects to females from prolonged, cyclic exposure to endogenous progesterone. In other taxonomic groups (e.g., primates, ungulates, marsupials, and rodents) in which multimale groupings are common, this reversible male sterilization technique could provide managers with the ability to control which males reproduce without eliminating their future reproductive capacity or social interaction.

Avian Soft Tissue Surgery.

Basic surgical instrumentation for avian soft tissue surgery includes soft tissue retractors, microsurgical instrumentation, surgical loupes, and head-mounted lights. Hemostasis is fundamental during the surgical procedures. The indications, approach, and complications associated with soft tissue surgeries of the integumentary (digit constriction repair, feather cyst excision, cranial wound repair, sternal wound repair, uropygial gland excision), gastrointestinal (ingluviotomy, crop biopsy, crop burn repair, celiotomy, coelomic hernia and pseudohernia repair, proventriculotomy, ventriculotomy, enterotomy, intestinal resection and anastomosis, cloacoplasty, cloacopexy), respiratory (rhinolith removal, sinusotomy, tracheotomy, tracheal resection and anastomosis, tracheostomy, pneumonectomy) and reproductive (ovocentesis, ovariectomy, salpingohysterectomy, cesarean section, orchidectomy, vasectomy, phallectomy) systems are reviewed.

Video Telescope Operating Microscopy.

Exotic pet veterinarians frequently have to operate on small animals, and magnification is commonly used. Existing endoscopy equipment can be used with a mechanical arm and telescope to enable video telescope operating microscopy. The additional equipment items and their specifics are described, and several case examples are provided.

Long-term survival of a cat receiving a renal allograft from an unrelated donor.

A 6-year-old, spayed female Persian cat in terminal renal failure was referred to the Veterinary Medical Teaching Hospital for renal transplantation. An allograft from an unrelated donor was placed in the right iliac fossa and cyclosporine and prednisolone were administered as immunosuppressive agents. More than 18 months after surgery the cat was clinically normal and azotemia was absent.

Microsurgery in the clinic and laboratory.

Laboratory animals have been crucial to the development of modern microsurgical techniques which are now routinely used in many clinical departments worldwide. In return, microsurgical techniques are important in biomedical research as they allow many surgical procedures to be performed on rodents instead of dogs, pigs or primates. This has obvious advantages in terms of low cost, the use statistically valid numbers for comparison and the availability of genetically defined animals which are more likely to give valid answers to immunological questions. Microsurgical reconstruction is important in plastic, orthopaedic, urogenital, vascular and peripheral nerve surgery in man and it is likely that it will become part of every surgeon's training in the near future. In this review, the instrumentation essential to any microsurgical enterprise and the sutures available are described. Basic microsurgical techniques for end-to-end and end-to-side anastomosis of small vessels and for joining peripheral nerves, oviducts and other tubular structures are given in outline. Techniques for transplanting kidney, heart, heart and lung, liver, spleen, pancreas, small bowel, stomach, testicle, ovary and whole joint are only outlined but key references are given. Finally, some of the clinical indications for microsurgical reconstruction are reviewed.

Anterior cervical microsurgical approach to the cranial base in the rabbit: technical note.

Current trends in research on craniofacial syndromes have led to enhanced interest in the cranial base as a contributory factor in the development of normal and abnormal midfacial structure. Indeed, attention has focused upon one particular growth plate in the posterior cranial base, the spheno-occipital synchondrosis, since it has been shown that alterations in this structure are associated with profound changes in craniofacial growth. In this report we describe a surgical approach to the cranial base of the rabbit that is safe, simple and reliable. It is applicable to neonatal as well as adult rabbits.

Microsurgical approach to the cerebellomedullar region in rat.

A microsurgical study was carried out on 20 randomized rats in order to delineate a safe technique for cerebellobulbar approaches. The procedure takes 20-30 min and can be performed with minimum blood loss if anatomical landmarks, particularly the m. obliquus capitis cranialis, are respected.

Prosthetic microvenous grafting in the rat femoral vein.

Male Wistar rats were used to evaluate microvenous prosthetic grafting techniques and microvenous prostheses in the femoral vein. With the end-to-end technique to implant microvenous prostheses, there was extensive exposure of vessel wall collagen especially at the suture sites. Thrombus formation then led to complete occlusion in all but one of the 32 prostheses 60 min after implantation. However, with the sleeve anastomotic technique there was only minimal exposure of collagen and minimal thrombus accumulation. Fifty-nine of the 64 microvenous prostheses implanted with the sleeve technique were patent after 1 day, 1, 3, 6, and 12 weeks (patency rate 92%). All patent microvenous prostheses were completely covered by an endothelial layer after 3 weeks. It was concluded that the rat is an appropriate experimental laboratory animal for evaluating new grafting techniques with microvenous prostheses and that the sleeve anastomotic technique gives the highest patency rates with microvenous prostheses.

Chronic implantation of transit-time flow probes on the ascending aorta of rodents.

This study describes the implantation of transit-time flow probes on the ascending aorta of rats while minimizing the risk of postoperative complications. Special emphasis is placed on our new method of rat intubation as well as the production of materials necessary for the implantation procedure such as endotracheal tubes and heparin bonded vessel catheters. The effects of these devices on the response to acute hypoxia were studied in rats following a 5-7 day recovery from the implantation procedure. Systemic and microvascular measurements were made on instrumented rats (n = 5) and non-instrumented controls (n = 3) that were ventilated with 21%, 15%, 10%, 8% and 5% oxygen. Arterial pressure, PO(2), lactate, and base deficit were not different between the implanted and control animals at any inspired oxygen concentration. Microvascular flow in the primary arterioles of the spinotrapezius muscle was also similar between the two groups at all inspired oxygen concentrations. We conclude that this novel methodology facilitates the measurement of whole body oxygen delivery in resting and haemodynamically-stressed rats.

Microsurgical excision of an abdominal mass in a gourami.

A female, sunset, thick-lipped gourami (Colisa labiosa) that weighed 8 g and was 5.4 cm from the snout to the end of the vertebral column was examined because of a 5-mm-diameter, midventrally located mass that had developed suddenly 1 month earlier. Cytologic examination of a sample obtained by use of fine-needle aspiration, survey radiography, positive-contrast radiography of the gastrointestinal tract, and Doppler ultrasonography were performed to evaluate the mass. These procedures were not able to provide a definitive diagnosis, but did facilitate surgical planning. The mass was excised, and the abdominal musculature was repaired, using microsurgical techniques. Redevelopment of the mass was not detected during the 5-month period after surgery. Histologic evaluation of the mass revealed an organized hematoma of undetermined cause. Successful management of this gourami illustrated that size should not be a deterrent to diagnostic evaluation and surgical intervention in diminutive fish.

Management of giant retinal tears in dogs.

Sixteen dogs with giant retinal tears resulting in total retinal detachment (360 degrees) underwent unilateral retinal reattachment surgery. In all dogs, complete vitrectomy was performed, and in most, perfluorooctane liquid was used to unroll and flatten the detached retina. Stainless steel tacks were used to anchor the retina to the choroid and sclera. Silicone oil was injected into the vitreous cavity to provide for permanent retinal tamponade. Endophotocoagulation or cryosurgery was used in several dogs to induce formation of permanent chorioretinal adhesions. Retinal attachment was successful in 14 of 16 dogs, and 13 of 14 dogs in which reattachment was successful retained some degree of vision. Complications included formation of cataracts and corneal erosions, development of glaucoma, and dislodgement of tacks.