Search

Objective— To evaluate the effect of knotting method on the mechanical properties of large diameter nonabsorbable monofilament suture materials. Study Design—In vitro mechanical evaluation. Methods— A conventional square knot was compared with the surgeon's knot, sliding half-hitch, and clamped square knot. Knotted suture loops were created in a uniform manner and acutely tensioned to failure (20 mm/min loading rate; n = 20 per knot type for each material). Stiffness, yield, and failure characteristics of USP #2 nylon, #2 polybutester, #2 polypropylene, 27 kg test monofilament nylon fishing line, and 27 kg nylon leader material were evaluated. Results— Compared with a conventional square knot, a surgeon's knot decreased stiffness for #2 polypropylene, 27 kg fishing line, and 27 kg leader (P < .05). A sliding half-hitch weakened all materials except 27 kg leader (P < .05). Clamping the first throw of a square knot increased the stiffness of 27 kg leader loops (P < .05). Conclusions— Based on clinically relevant parameters (stiffness and yield), knotting method had no effect on #2 nylon and #2 polybutester. The surgeon's knot is not recommended for #2 polypropylene and 27 kg fishing line and leader material. A sliding half-hitch decreased the yield of leader material. Clamping the first throw of a square knot had no adverse effects on acute properties of tested materials; it increased the stiffness for leader material. Clinical Relevance— Knotting method does influence the structural properties of suture materials and should be considered when tying knots under tension.

Objective— To evaluate the effectiveness of a forced-air warming blanket (FAWB) in minimizing anesthetic-induced hypothermia in cats, and to examine the relationship between esophageal and other estimates of body temperature during skin surface warming. Study Design— Prospective, randomized cross-over trial. Animals— Eight adult domestic shorthair cats (four males and four females) weighing 2.3 to 4.5 kg. Methods— Each cat was anesthetized with halothane in oxygen on four occasions and covered with a modified FAWB. Air delivered to the cats by the FAWB was warmed to approximately 43°C. Each trial lasted 90 minutes and was divided into two consecutive 45-minute periods, during which the FAWB was activated or inactivated thus creating four treatment trials: off/off, on/off, on/on, off/on. Measurements of body temperature from the caudal esophagus, deep rectum, toe-web, and tympanic membrane were recorded at regular intervals throughout each trial and compared. Results— A steady decline in body temperature was observed throughout each trial. Mean body temperature in the cats receiving continual skin surface warming (on/on) was significantly higher than in those receiving no active warming (off/off) and those receiving delayed warming (off/on), from 45 minutes onwards. By 90 minutes, the mean body temperature of cats warmed continuously was 0.9°C higher than in those with no active warming. Notable differences in body temperature were detected between all measurement sites, with the exception of esophagus versus rectum. Rectal and esophageal temperatures did not differ at any time point. Tympanic membrane temperatures measured with either device were lower than esophageal temperatures. Conclusions— The modified FAWB was effective in minimizing the degree of hypothermia experienced in cats anesthetized with halothane for 90 minutes. Deep rectal temperature was an accurate reflection of esophageal temperature in these cats. Clinical Relevance— Forced air warming blankets may prove successful in minimizing anesthetic-induced hypothermia in cats.

This paper reports five new cases of intrathoracic tracheal rupture in cats, and summarizes these cases in conjunction with 11 cases from the literature. Most cats had no obvious respiratory signs at the time of injury, and in half of them the tracheal rupture was the only injury. The interval from trauma to onset of dyspnoea ranged from 1 to 28 days (median 12.5 days). Radiographic findings include loss of continuity of the trachea, often with a gas-filled diverticulum present between separated tracheal rings. With careful attention to surgical technique and anaesthetic management the prognosis for these cats is excellent. All eight of the cats reported in the last 14 years having surgical correction survived and returned to normal. The surgical anatomy, approach and tracheal anastomosis technique is described and recommendations for anaesthetic management are made.

The congenital portosystemic shunts in 23 dogs were closed partially in 18 and completely in five with a single silk ligature. The clinical results were studied and the degree of portosystemic shunting was measured by a scintigraphic method, the results being expressed as the shunt index (SI). In 17 of the dogs, the mean (sd) SI decreased from 0.92 (0.16) before surgery to 0.34 (0.25) during surgery after the attenuation of the shunt, and then to 0.10 (0.12) one month later. The dogs' venous ammonia concentration decreased from 203 (122) microM before surgery to 36 (18) one month after surgery. At the same time the clinical scores improved significantly. There were positive correlations between the SI and the general evaluation of the dogs' well-being by their owners (rs = 0.60), the ammonia concentration (rs = 0.86), and the diameter of the shunt (rs = 0.86). In the other six dogs, the intraoperative and/or postoperative SI was high. In two of them the shunt was further attenuated during a second operation, which resulted in lower SI values; in two a second small shunt was responsible for the high SI; in one multiple portosystemic shunts were found postmortem; and one dog was lost to follow-up.

An eight-year-old, sexually intact, male, 37 kg crossbred dog was referred for investigation of two acute episodes of intestinal bleeding and severe anaemia within a five-month period. There was no evidence of coagulopathy or underlying systemic disease. Technetium-labelled red blood cell scintigraphy suggested the colon as the site of bleeding. Colonoscopy identified a focal area of dilated and tortuous mucosal blood vessels. Histopathology of the resected colon revealed vascular ectasia (angiodysplasia). At nine months post-resection, the dog remained healthy and free of any overt intestinal haemorrhage.

A six-year-old, male Doberman pinscher was presented for acute onset of upper motor neuron tetraparesis. An extradural compressive lesion compatible with intervertebral disk rupture at the sixth to seventh cervical (C6-C7) disk space was evident on myelography. A large, gelatinous mass of pure cryptococcal organisms causing spinal cord compression was identified upon exploratory surgery. Removal of the mass caused relief of clinical signs. No evidence of involvement of other organ systems was found; however, serum and cerebrospinal fluid titers were positive for cryptococcal infection. The dog was treated with fluconazole (5.5 mg/kg body weight, per os sid) until serum titers for cryptococcal infection were negative at seven months postsurgery. To the authors' knowledge, this is the only report of a dog with cryptococcosis treated successfully using fluconazole as a sole agent.

Avian surgery is an exercise of preparedness; this statement is never so true as in emergency and critical care situations. The techniques used in avian surgery are significantly different from those used in larger species and require microsurgical techniques. Before initiating a surgical procedure, the patient must be evaluated and, in many cases, prepared or preconditioned. Rarely is surgery such an emergency that the prognosis would not be improved by readying the patient. Techniques of tissue handling, approaches to the coelomic cavities and a select number of surgical procedures are described.

Forty-seven owners of 48 dogs surgically treated for cranial cruciate ligament deficiency were asked to assess the outcome of treatment at one year postsurgery. A standard visual analogue scale assessment tool was used in all cases and owners were asked to score a variety of generic and disease-specific features. The reliability and responsiveness of the assessment tool were estimated and found to be acceptable; generic features, such as 'level of disability', showed the greatest reliability and responsiveness. The results of assessments by owners were compared to assessments by a veterinary surgeon but few significant correlations were found. Assessments by owners appear to be a useful outcome measure in this disease but are unlikely to be directly comparable to assessments by a veterinary surgeon.

The modified Forssell's procedure was performed on 10 horses in an attempt to cure oral stereotypies. Three horses were cured completely, two horses were considerably improved, and five horses continued to perform the stereotypy after periods of remission ranging from two weeks to six months. This rate of success for the modified Forssell's procedure, as in other published reports, was lower than for the original Forssell's procedure. Surgery to eliminate a stereotypical behaviour pattern may exacerbate the stress for an animal and the modified Forssell's procedure can no longer be recommended for the treatment of oral stereotypies in horses.

The surgical treatment of intrahepatic portosystemic shunts in six cats is described. The preoperative diagnoses were based on the results of abdominal ultrasonography, and mesenteric portography was used during surgery to confirm the diagnosis and establish the morphology of the shunting vessel. In four of the cats the shunt vessel passed through the left division of the liver, compatible with a patent ductus venosus (PDV), in one cat the shunt passed through the central hepatic division and in the other cat it passed through the right hepatic division. During surgery the shunt vessel was manipulated directly either intrahepatically, or post hepatically in the four cats with PDV. In five cats the shunt vessel was partially ligated, and in the other the vessel was completely ligated. The attenuation procedure produced a mean increase in mesenteric venous pressure of 17 cm H2O, with a range from 14 to 20 cm. All the cats recovered from the surgical procedure, but one developed neurological signs shortly after the operation and died from respiratory failure. Four of the cats were clinically normal and required no medication by one month after the operation. One cat required long-term medication to control its continued clinical signs.

Surgery in animals for palliation of clinical signs and treatment of cancer metastases is becoming more popular. Patients must be selected carefully and clear treatment goals established to maximize efficacy and minimize treatment-related morbidity and mortality. Palliative treatment is rendered primarily to control clinical signs and secondarily to prolong life. Ironically, metastasectomy is often performed with the intent to cure. For both considerations, the clinician must be knowledgeable of the natural history of the affecting neoplasia (i.e., how will the patient fare without treatment) and the success rates and expected complications of the surgical procedures being considered. Clinical guidelines for patient selection are presented and discussed for palliative treatment and metastasectomy. Although data are available in the human and veterinary medical literature to aid decision making, sound clinical judgment remains most important for proper patient selection and care.

Preoperative assessment of the cancer patient can be broken down into: (1) What is it? (2) Where is it? and (3) What is the status of the patient? Evaluation of local disease begins with obtaining and interpreting cytologic or histologic (biopsy) samples. Tumor staging involves the assessment of tumor invasion into local tissues, draining lymph nodes, and distant sites, especially the pulmonary parenchyma. Staging is performed with the aid of imaging techniques and special procedures such as lymph node and bone marrow aspiration. Because many veterinary cancer patients are geriatric, examination of physiologic patient status through laboratory and other diagnostic avenues is vital to the appropriate selection and success of therapy. After these questions are answered, appropriate treatment options and an ultimate treatment plan can be formulated. This article describes logical and practical approaches for diagnosis, staging, patient assessment, and treatment planning of the animal presented with tumor disease. With appropriate preoperative assessment, we can offer our patients and clients the best care possible.

Soft tissue sarcomas (STS) are mesenchymal tumors arising from connective tissue elements and are grouped together based on a common biologic behavior. The most common histologic types include malignant peripheral nerve sheath tumors (schwannoma and neurofibrosarcoma) "hemangiopericytoma," fibrosarcoma, and malignant fibrous histiocytoma. These tumors are relatively slow growing yet locally invasive with a high rate of recurrence following conservative management. Appropriate preoperative planning and aggressive surgical resection often result in long-term remission or cure. Identification and evaluation of resection margins are paramount in appropriate case management. The addition of radiotherapy after surgical resection can aid in remission for incompletely resected masses. Systemic chemotherapy for STS should be considered for high-grade tumors with a moderate metastatic potential. Potential prognostic factors include grade, resection margins, size, location, histologic type, and previous treatment, with grade and margins being the most important. Tumor types classified as STS that differ slightly in their presentation or treatment, including synovial cell sarcoma, rhabdomyosarcoma, liposarcoma, and vaccine-associated STS in cats, are discussed. Soft tissue sarcomas can be a frustrating disease to treat, but adherence to solid surgical oncology principles can greatly increase the odds of good disease control.

Skeletal neoplasms in pet animals are uncommon, but can represent a diagnostic and treatment challenge for the veterinary clinician. Osteosarcoma represents the most common histology of primary bone tumor and although the prognosis after treatment is still gaurded, major strides have been made in the treatment of this disease. Treatment success, however, requires a multidisciplinary approach. Additional histologic types cannot be ignored from the diagnosis of cases presenting as bone neoplasms, and many of these can have excellent long-term prognoses if treated appropriately. This article discusses the presentation, diagnosis, and treatment of skeletal neoplasms in general with a specific emphasis on osteosarcoma.

The instruments utilized in ophthalmic surgery are described along with their intended uses. The sterilization and storage of surgical instruments are also discussed. To guide the surgeon in the selection of instruments, examples of instrument packs are included.

Corneal surgery is a common and essential part of veterinary ophthalmology and ranges from simple linear keratotomy for indolent ulcers to penetrating keratoplasty for restoration of optical clarity. Success in corneal surgery relies on an understanding of corneal anatomy, physiology and wound healing, meticulous attention to detail, microsurgical equipment and techniques, and use of appropriate preoperative, intraoperative, and postoperative medications. Surgical management of corneal disease is indicated for corneal ulceration, excision of a mass lesion, reconstructive procedures, therapeutic indications, optical restoration, and cosmetic purposes.

Review of the functional anatomy of ocular adnexal tissues is followed by presentation of surgical procedures aimed at correcting conditions of the eyelids, conjunctiva, and third eyelids of small animals. Procedures used effectively by the primary author are described in detail including instances where combination procedures may be indicated. Some newer, recently described techniques are also briefly discussed. Illustrations of applied anatomy and multiple surgical techniques are provided by illustrator and coauthor Dr. Gheorghe Constantinescu. References are given to encourage readers to further explore alternative techniques focusing on the surgical correction of adnexal diseases of dogs and cats.

Retinal detachment surgery in human patients is currently 90% successful, with most detachments amenable to treatment by scleral buckling procedures. The main obstacle to achieving comparable results in veterinary patients is the active nature of our patients during the postoperative convalescent period. Adapting current techniques to include short-term chorioretinal adhesion by way of tacking, cyanoacrylate adhesives, or other methods has shown substantial promise and should be further investigated in veterinary species. The technology and methods are currently available to produce success rates comparable to those achieved in human patients, and the near future promises to bring further refinements in veterinary applications.

Most cases of glaucoma in small animals ultimately require surgical treatment for long-term control of intraocular pressure. Surgical procedures that have the potential to preserve vision in acute cases are categorized into those that reduce aqueous production (cyclodestructive techniques). Salvage procedures for irreversibly blind eyes include enucleation, implantation of an intraocular prosthesis, and pharmacologic ciliary body ablation. The indications, surgical technique, and complications of these procedures are discussed in this article.

Five cats underwent lobectomy for the management of pneumonia. The mean presurgical duration of treatment was eight months. A potentially immunosuppressive disease process was present preoperatively in two of the five cats. Preoperatively, two of the cats had radiographically diffuse pneumonia, while three had focal pneumonia. A single pulmonary lobe was removed in four cats, with one cat having two pulmonary lobes removed. There were no life-threatening complications and no clinical recurrence noted during a mean follow-up period of 37.8 months. The benefit of pulmonary lobectomy in focal pneumonia may lie in removing the nidus of infection. In diffuse, chronic or medically refractory pneumonia, obtaining an aetiological diagnosis may be the main benefit of lobectomy. Selective lobectomy for the treatment of pneumonia may be beneficial but a thorough preoperative evaluation is warranted.

Multicentre Confidential Enquiries into Perioperative Equine Fatalities (CEPEF) have not been conducted since the initial CEPEF Phases 1-3, 20 years ago.To collect data on current practice in equine anaesthesia and to recruit participants for CEPEF-4.Online questionnaire survey.An online questionnaire was prepared and the link distributed internationally to veterinarians possibly performing equine anaesthesia, using emails, posters, flyers and an editorial. The questionnaire included 52 closed, semiclosed and open questions divided into 8 subgroups: demographic data, anaesthetist, anaesthesia management (preoperative, technical equipment, monitoring, drugs, recovery), areas of improvements and risks and motivation for participation in CEPEF-4. Descriptive statistics and Chi-squared tests for comparison of categorical variables were performed.A total of 199 questionnaires were completed by veterinarians from 14 different countries. Of the respondents, 43% worked in private hospitals, 36% in private practices and 21% in university teaching hospitals. In 40 institutions (23%) there was at least one diplomate of the European or American colleges of veterinary anaesthesia and analgesia on staff. Individual respondents reported routinely employ the following anaesthesia monitoring modalities: electrocardiography (80%), invasive arterial blood pressures (70%), pulse oximetry (60%), capnography (55%), arterial blood gases (47%), composition of inspired and expired gases (45%) and body temperature (35%). Drugs administered frequently or routinely as part of a standard protocol were: acepromazine (44%), xylazine (68%), butorphanol (59%), ketamine (96%), diazepam (83%), isoflurane (76%), dobutamine (46%), and, as a nonsteroidal anti-inflammatory drug, phenylbutazone (73%) or flunixin meglumine (66%). Recovery was routinely assisted by 40%. The main factors perceived by the respondents to affect outcome of equine anaesthesia were the preoperative health status of the animal and training of the anaesthetist.Current practice in equine anaesthesia varies widely, and the study has highlighted important topics relevant for designing a future prospective multicentre cohort study (CEPEF-4). The Summary is available in Chinese - see Supporting information.

To evaluate knot security and tensile failure load of suture tied in simple interrupted, beginning continuous, and ending continuous patterns for 11 suture materials commonly used in small animal surgery.Mechanical study.For each of 11 suture material types, and 5 knot sizes (2, 3, 4, 5, and 6 throws) 2 surgeons each tied 6 knots (n = 12 for each knot size in 11 suture materials). Three types of patterns were evaluated: a simple interrupted square knot, a square knot beginning a simple continuous pattern, and the knot ending a simple continuous pattern. All knots were incubated in healthy canine donor plasma at 40°C for a minimum of 24 hours. Sutures were evaluated for knot security (knots untied, suture failed by breaking, suture slipped from the clamps, or suture untied before testing) and maximum load carried before knot slippage or knot failure (termed tensile failure load).Significant differences were found in knot security and tensile failure load among suture types. There was no significant difference between the simple interrupted knots and the knots at the beginning of a simple continuous pattern; however, both were significantly less likely to fail than the knots tied at the end of a simple continuous pattern. The number of throws per knot had a significant effect for knot security and tensile failure load. Surgeon experience had a significant effect on failure mode and tensile failure load.Suture type, number of throws per knot (knot size), suture pattern, and surgeon experience play an important role in knot security and should be considered when performing surgery.

John Innes discusses developments in treating common articular disorders, such as dysplasia, cruciate ligament rupture and arthritis, from surgical and medical options to the promising targeted genetic medicine.

Objective To investigate whether soft palate resection and tonsillectomy with a bipolar vessel sealing device (BVSD) improves clinical respiratory score. To document histopathological changes to tonsillar tissue following removal with a BVSD. Methods & Results Case series of 22 dogs with clinical signs of upper respiratory obstruction related to brachycephalic airway syndrome. Soft palate and tonsils were removed using a BVSD. Alarplasty and saccullectomy were also performed if indicated. A clinical respiratory score was assigned preoperatively, 24-h postoperatively and 5 weeks postoperatively. Excised tonsillar samples were measured and then assessed histologically for depth of tissue damage deemed to be caused by the device. Depth of tissue damage was compared between two power settings of the device. Soft palate resection and tonsillectomy with a BVSD lead to a significant improvement in respiratory scores following surgery. Depth of tissue damage was significantly less for power setting 1 compared with power setting 2. Using power setting 1, median calculated depth of tonsillar tissue damage was 3.4 mm (range 1.2–8.0). One dog experienced major complications. Conclusion Soft palate resection and tonsillectomy with a BVSD led to significant improvement in clinical respiratory score.

Brain tumors occur commonly in small animals. The clinical history and physical examination findings can strongly suggest their presence. Specifically, an older dog with onset of seizures and behavioral changes, or an older cat with behavioural changes and weakness, should be further evaluated for the presence of a brain tumor. A thorough neurological examination should be performed to localize the lesion(s). Groups of neurological signs will suggest the tumor to be cerebral, cerebellar, or brainstem. Cerebral tumors without brainstem signs carry the best prognosis, especially for cats. Patients suspected of having brain tumors should be imaged with computed tomography, or magnetic resonance imaging. Initial medical therapy includes anticonvulsants and glucocorticosteroids. Cerebral tumors not located on the floor of the calvarium can be successfully excised. These and other tumors can also be treated with radiation therapy.

Neurological deficits suggesting trauma to the spinal cord in the thoracolumbar area are the most common clinical presentation of neurosurgical conditions. By far, the most common cause of thoracolumbar spinal cord dysfunction is intervertebral disc disease. Disc herniation and subsequent spinal cord compression usually requires prompt medical treatment, then referral for high detail radiographs, myelogram, and surgical decompression. Other causes of thoracolumbar spinal cord dysfunction include neoplasia, discospondylitis, fibrocartilaginous embolism, and degenerative myelopathy.

Inadequate peripheral nerve regeneration as a result of trauma contributes greatly to the morbidity of surgical patients. Animals admitted as an emergency often have concurrent orthopaedic injuries that impair mobility and may mask peripheral nerve dysfunction if a thorough neurological examination is not performed. This article reviews the pertinent anatomy of the peripheral nervous system as well as the degenerative and regenerative responses that occur in traumatized nerves. Physical examination and electrodiagnostic techniques that characterize the extent of nerve impairment are described. The management of peripheral nerve lacerations for open and closed wounds is detailed, as well as the presenting clinical signs and prognosis for brachial plexus avulsions, sciatic nerve damage, and sacrococcygeal injury.

Lumbosacral conditions are now recognized as compromising a significant percentage of problems for dogs and cats with rear limb abnormalities. Diagnosis is based on logically ruling out the more common maladies and then performing specific diagnostic procedures that definitively show the lesion(s).

The surgical and medical records of 67 dogs and nine cats which underwent median sternotomy over a five-year period were reviewed. The indication for median sternotomy and the short and longer term complications were recorded. Twenty-six of the dogs died or were euthanased within 48 hours of the surgery as a consequence of the pre-existing disease or complications of the intrathoracic surgical procedure. A further four dogs were enthanased between 48 hours and 14 days following confirmation of neoplastic processes. Thirty-seven dogs were alive at 14 days: of these, seven dogs (19 per cent) experienced short-term wound complications, including haemorrhage, wound infection, thoracic limb neurological deficits and excessive postoperative discomfort. Of the 37 dogs alive for longer term follow-up, eight dogs (22 per cent) experienced wound complications, including haemorrhage, sternal fracture, sternal osteomyelitis and delayed wound healing. No complications were noted in the cats.

Static locked nailing was used to repair fractures of the femoral diaphysis in 15 dogs. The implant consists of a 5, 6, or 7 mm diameter stainless steel rod made up of two parts: the body of the nail, in which there are 13 threaded holes, and a piece without holes that contains a slot for anchoring the jig. Good limb function was obtained after less than 3 weeks in 12 dogs and these dogs remained sound throughout the study. Radiographic examination revealed fracture healing in 11 of the dogs, between 8 and 16 weeks after surgery. One dog was not returned for follow-up evaluation until 22 weeks after surgery; complete healing was apparent from radiographic examination. The remaining three dogs had to have additional operations, one because of lameness caused by excessive length of the distal screws, one because of a nonunion, and the third because of a sequestrum. Fracture healing in these dogs was observed at 18, 21, and 24 weeks respectively. Loosening of one screw and angulation of the bone occurred in one dog. These complications had no adverse effects on clinical outcome.

Five dogs were diagnosed as having unilateral separation of the otic cartilages (auricular and annular). Four dogs had sustained prior trauma (hit by a car). Clinical signs were typical of ear canal stenosis and included swelling at the base of the ear (n = 2), periotic fistulation (n = 2), head tilt toward the affected side (n = 2), and pain when opening the mouth (n = 1). Palpation revealed separation of the horizontal and vertical ear canals. Otoscopic findings included a shallow ear canal and a pseudotympanic membrane across the proximal end of the auricular cartilage. Findings at surgery confirmed the diagnosis of cartilage separation and included an exudate-filled horizontal ear canal and a blind-ending vertical ear canal. Surgical treatment involved isolating the distal end of the annular cartilage (horizontal ear canal), opening and evacuating the horizontal ear canal, and suturing the open end of the annular cartilage to the skin. The length of annular cartilage was variable among the dogs, although each dog had sufficient horizontal canal to appose skin to otic epithelium. The vertical ear canal was not surgically dissected or manipulated. The mean follow-up period was 46 +/- 14 months (range, 31 to 68 months). All five dogs had patent horizontal ear canals when examined at the follow-up examination.

Two dogs had right divisional intrahepatic portacaval shunts within the right lateral lobe of the liver. In both dogs, an extrahepatic portacaval vascular anastomosis was created, using an autologous right external jugular vein graft. The intrahepatic shunts were completely attenuated using a prehepatic intravascular caval approach. The creation of the vascular graft allowed postattenuation rises in portal pressure to be controlled, preventing the development of life threatening portal hypertension. Both dogs recovered from the procedure. One dog is clinically normal and does not require medication (8 months postoperatively); the other dog was euthanatized 5 months after surgery because of renal failure. Scintigraphy studies, performed before surgery, showed significant shunting of portal blood away from the liver (shunt indices 65% and 59%), whereas, similar studies done 4 weeks afterwards showed almost normal portal blood flow (shunt indices 16% and 18%, respectively).

The carbon dioxide laser has become an important surgical instrument in human and veterinary medicine. The unique properties of this laser make it the instrument of choice for precise incision, coagulation, and vaporization of tissue at the body surface with minimal morbidity to the patient. This article describes the instrumentation and techniques used to perform a variety of equine general surgical procedures with the carbon dioxide laser. The benefits of surgery using the carbon dioxide laser include precise dissection with minimal trauma to adjacent tissues, good hemostasis, and the ability of the laser beam's thermal properties to kill bacteria or tumor cells in the operative field.

Equine surgery continues to benefit from advances in laparoscopic techniques. Descriptions of the normal anatomy of the standing horse and advances in instrumentation have improved our ability to perform laparoscopic surgery in both standing and dorsally recumbent horses. The common uses for laparoscopy are diagnostic laparoscopy, cryptorchidectomy, ovariectomy, and diagnostic thoracoscopy. Other reported uses include inguinal hernia repair, ruptured bladder repair, and ventral colopexy.

In this article, videoendoscopy in conjunction with high-speed treadmill exercise and other specialized diagnostic techniques used to measure upper airway function are reviewed as they pertain to the four most commonly diagnosed functional upper airway obstructions: (1) laryngeal hemiplegia, (2) arytenoid chondritis, (3) epiglottic entrapment, and (4) intermittent dorsal displacement of the soft palate. Using experimental and clinical findings obtained with these new instruments and diagnostic techniques, current recommendations for surgery of these obstructions are presented.

In recent years fracture fixation in the horse has changed significantly. New devices, mainly adapted from the human field, have been successfully introduced into large animal surgery. Examples of such implants include the DCS/DHS implant system, the self-tapping screw, the cannulated screw, and the pinless external fixator. However, new devices have also been developed exclusively for equine fracture management, including the interlocking intramedullary nail and the external skeletal fixation device. With these devices the surgeon has more options for repairing fractures in horses. Nevertheless, many problems are still unsolved. Indications exist that during the next few years new, exciting fracture fixation systems will be developed, providing further advancements in the quest for the ideal implant for horses. However, the development stages of these devices are such that mentioning the possibilities here is premature.

Transendoscopic laser surgery provides equine surgeons with a safe, reliable, and minimally invasive method of performing many surgical procedures in the upper respiratory tract. Although the Nd:YAG laser has proven efficacy, other newer lasers such as the diode and holmium: YAG lasers may prove to be useful tools for equine upper respiratory tract surgery. Long grasping forceps and a high quality fiberoptic or video endoscope are critical components necessary for performing transendoscopic laser surgery. For many of the most common upper respiratory tract abnormalities, a laryngotomy can be eliminated, morbidity is minimal, the horse can often return to normal exercise in approximately 7 to 14 days, and trainer and owner acceptance is excellent. Transendoscopic laser surgery is most likely to be cost effective in large referral practices or in a university setting.

Fourteen interfragmentary orthopedic wire configurations were tested in torsion using a transverse fracture polyvinylchloride pipe model. These models included single and double Kirschner pins with and without orthopedic wire added to the configuration. The orthopedic wire was applied in either an encircling, figure-of-eight (skewer pin), or cruciate pattern. Double Kirschner pins were applied in a mono- or biplanar fashion. An external fixator model was also tested. Stiffness, yield load, safe load, and energy of absorption were measured and calculated for each model. Orthopedic wire added to any configuration increased stiffness. All single pin configurations with orthopedic wire and the external fixator had the highest stiffness. Two Kirschner pins had a higher torsional yield load and safe load than single pin configurations with or without orthopedic wire. The external fixator model had the highest torsional yield load, safe load and energy of absorption of all configurations tested. However, the external fixator was only significantly different in safe load from the 900 biplanar configurations with wire and the cross pin configuration with encircling wire. The 900 biplanar configurations with wire and the cross pin configuration with encircling wire were equally as effective as the external fixator model in yield load and energy of absorption.

The speed of mask induction using an in-circuit vaporizer may be influenced by vaporizer setting. To investigate this in clinical patients, 18 dogs were randomly assigned to one of three groups. Each dog was premedicated and then mask induced with isoflurane using a Stephen's in-circuit vaporizer set at 1/2, 3/4, or full ON. We determined inspired isoflurane and oxygen concentrations at the level of the mask, respiratory rate, resistance to mask induction, and time to intubation. No significant differences were found between groups in resistance to induction or in time to intubation. At settings of 3/4 and full ON, inspired isoflurane concentrations at time of intubation ranged from 3.3% to 8.25%, and were significantly higher than those resulting from the 1/2 setting (range 2.1% to 4.6%). We conclude that it may be preferable to avoid settings greater than 1/2 when using the Stephen's vaporizer for mask induction because of the potential adverse effects of high inspired inhalant anesthetic concentrations. In addition, use of higher vaporizer settings may not significantly speed induction.

The clinical effects of sevoflurane, isoflurane, and halothane anesthesia with or without nitrous oxide, were compared in healthy, premedicated cats breathing spontaneously during 90 minutes of anesthesia. The effect of nitrous oxide in accelerating the induction of and recovery from anesthesia was more evident for halothane than for sevoflurane or isoflurane. The cats recovered more rapidly from sevoflurane-oxygen than from either halothane- or isoflurane-oxygen. Heart rates did not significantly change during anesthesia with any of the anesthetics. Arterial blood pressures during sevoflurane-oxygen anesthesia were somewhat higher than those with either isoflurane- or halothane-oxygen. There were no significant differences in arterial blood pressures among sevoflurane, isoflurane, and halothane anesthesia when combined with nitrous oxide. The respiration rate during sevoflurane-oxygen was similar to that during halothane-oxygen. There were no significant differences in respiration rate among sevoflurane, isoflurane, and halothane anesthesia when combined with nitrous oxide. The degree of hypercapnia and acidosis during sevoflurane anesthesia was similar to that observed during isoflurane anesthesia and less than during halothane anesthesia. The three anesthetic regimens, with or without nitrous oxide, induced a similar degree of hyperglycemia and hemodilution during anesthesia. Serum biochemical examination did not reveal any hepatic or renal injuries after each anesthesia.