Reduction and temporary stabilization of acetabular fractures using ASIF mandibular reduction forceps: technique and results using plate fixation in 25 dogs

OBJECTIVE

To report the results of acetabular fracture fixation in 25 dogs in which a specialized forceps (ASIF mandibular reduction forceps, Synthes USA, Paoli, PA) was used to obtain fracture reduction and stabilization.

STUDY DESIGN

A retrospective clinical study.

ANIMAL POPULATION

Twenty-five client-owned dogs with traumatic acetabular fractures.

METHODS

The mandibular reduction forceps (MRF) use a screw on each side of the fracture to attach the clamp directly to the bone and permit direct manipulation of the fragments. Medical records from 25 dogs with acetabular fractures were reviewed to determine the effectiveness of this technique in obtaining, and then maintaining, fracture reduction while a plate was being applied.

RESULTS

Clinical results were considered successful in 24 of 25 dogs; the small size of 1 dog prevented application of the MRF. The final reduction and fixation of the fractures was evaluated as anatomic in 17 dogs, near-anatomic in 6 dogs, and nonanatomic in 1 dog.

CONCLUSIONS AND CLINICAL RELEVANCE

Application of the MRF is an effective technique for aiding the reduction of acetabular fractures in dogs. It maintains reduction while simultaneously permitting unimpeded access to the dorsal acetabular rim, thus facilitating accurate contouring of a plate. Accurate reduction and rigid fixation of articular fractures is essential to prevent secondary osteoarthritis.

Preparation and equipment useful for surgery in small exotic pets

Because many exotic pets are so small, the instrumentation and equipment used for surgery are different from in larger animals. Magnification greatly improves the surgeon's ability to accomplish surgeries in small patients and helps to provide hemostasis because small amounts of blood are significant in these tiny patients. Microsurgical instrumentation is important to allow for proper tissue handling and suture placement. Various other considerations, instrumentation, and equipment are useful when performing surgery on small exotic pets.

Nonreproductive surgery in small mammals

The sophistication of soft-tissue surgery techniques in small mammals is increasing rapidly. Exotic animal practitioners must be familiar with the diseases, conditions, and anatomic variations of each small-mammal species. The small size of these patients should not preclude the use of technologic advances available for other small animals. Despite these challenges, successful resolution of surgical problems in small exotic mammals is not only possible but also should be the expected result of veterinarians' efforts in such cases.

History, Instrumentation, and Techniques of Flexible Endoscopic Laser Surgery in Horses

There are clearly a number of applications for which flexible endoscopic laser surgery has become the state of the art in equine surgery, and the Nd:YAG laser seems to be the most versatile instrument for this type of surgery. Nevertheless, it is critical to understand the advantages and disadvantages of each laser technique. For example, the Nd:YAG laser used in a noncontact fashion seems to be superior when ablation of tissue is required such as treatment of upper airway masses. Conversely, contact Nd:YAG laser techniques have proven themselves to be superior when more precise cutting is advantageous such as treatment of epiglottic entrapment. Ultimately, it seems that a range of lasers is necessary to ensure selection of the most appropriate technique, adding significantly to the expense of equipment but improving the outcome for a range of equine diseases.

Bacterial contamination of suction tips used during surgical procedures performed on dogs and cats

OBJECTIVE

To determine prevalence of bacterial contamination of surgical suction tips.

SAMPLE POPULATION

Surgical tips used during 44 surgical procedures performed on 42 dogs and 2 cats.

PROCEDURE

Surgical procedures were classified into 1 of 3 categories according to degree of bacterial contamination of the surgical site (clean, clean-contaminated, contaminated). Two sets of suction apparatuses were used for test and control suction tips. Test tips were used normally to suction blood and fluid, whereas control tips were placed on the surgical drapes but not in the surgical wound. Suction tips were collected aseptically and placed into thioglycolate broth tubes for qualitative aerobic and anaerobic bacterial culture at the end of each procedure.

RESULTS

Test and control suction tips were contaminated with bacteria during 30 of 44 (68%) procedures. Staphylococcus spp were the predominant bacteria in tips used during clean and clean-contaminated surgeries. When surgery was performed on clean-contaminated or contaminated wounds, prevalence of isolation of other bacteria such as Pseudomonas spp, Streptococcus spp, and Escherichia coli from both test and control suction tips was higher than for clean wounds. Mean time of procedures during which both test and control suction tips became contaminated was not significantly different from time of procedures during which neither tip became contaminated.

CONCLUSION AND CLINICAL RELEVANCE

Surgical suction tips often become contaminated during standard veterinary surgical procedures. The risk of wound infection after surgery may be influenced by bacterial contamination of surgical suction tips.

Facilitation of Asian elephant (Elephas maximus) standing immobilization and anesthesia with a sling

An Asian elephant (Elephas maximus) required general anesthesia for orthopedic foot surgery. The elephant was unable to lie down, so it was placed in a custom-made sling, administered i.m. etorphine hydrochloride in the standing position, and lowered to lateral recumbency. General anesthesia was maintained with isoflurane administered through an endotracheal tube. After surgery, the isoflurane anesthesia was terminated, with immobilization maintained with additional i.v. etorphine. The elephant was lifted to the vertical position, and the immobilizing effects of etorphine were reversed with naltrexone. The suspension system and hoist for the sling were designed specifically for the elephant house.

Warming with a forced air warming blanket minimizes anesthetic-induced hypothermia in cats

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 degrees 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 degrees 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.

An in vitro comparison of hollow ground and trocar points on threaded positive-profile external skeletal fixation pins in canine cadaveric bone

OBJECTIVE

To compare the microstructural damage created in bone by pins with lathe-cut and rolled-on threads, and to determine the peak tip temperature and damage created by positive-profile external fixator pins with either hollow ground (HG) or trocar (T) tips during insertion.

STUDY DESIGN

An acute, in vitro biomechanical evaluation.

SAMPLE POPULATION

Twenty-seven canine tibiae.

METHODS

Lathe-cut thread design with T point (LT-T), rolled-on thread design with T point (RT-T), and rolled-on thread design with HG point (RT-HG) pins were evaluated. Twenty pins of each type were inserted under constant drilling pressure into 12 canine tibiae (12 diaphyseal and 8 metaphyseal sites per pin type). Peak pin tip temperature, drilling energy, end-insertional pin torque, and pullout force were measured for each pin. For the histologic study, five pins of each type were inserted into cortical and cancellous sites in 15 additional tibiae. Entry and exit damage, and thread quality were assessed from 100 micron histologic sections by using computer-interfaced videomicroscopy.

RESULTS

T-tipped pins reached higher tip temperature in both diaphyseal and metaphyseal bone compared with HG-tipped pins. RT-T pins had higher pullout strength (diaphyseal) and end-insertional torque compared with other combinations. No differences in drilling energy or insertional bone damage was found between the three pin types (P < .05).

CONCLUSIONS

T-tipped pins mechanically outperformed HG-tipped pins. Pin tip and thread design did not significantly influence the degree of insertional bone damage.

CLINICAL RELEVANCE

T-tipped pins may provide the best compromise between thermal damage and interface friction for maximizing performance of threaded external fixator pins.

Emergency avian surgery

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.

Principles of microsurgery

The surgical principles and techniques used in ophthalmic microsurgery differ considerably from those used in general surgery. Successful ophthalmic microsurgery requires that the surgeon understand not only the design and complexities of the operating microscope, but how tissues are affected by minute manipulations with microsurgical instruments. Furthermore, ophthalmic microsurgery requires a detailed understanding of how microsurgical techniques need to be adjusted to accommodate the unique features of ocular tissues such as conjunctiva, cornea, and lens. A diligent effort to master the principles of ophthalmic microsurgery is probably the single most important prerequisite to becoming an accomplished ophthalmic surgeon.

Surgery for glaucoma

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.

Ophthalmic instrumentation

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.

Surgery for lens instability

Lens luxation is a common and potentially blinding disease of dogs. If left untreated, degenerative changes in the pathways for aqueous humor result in glaucoma; however, if the lens is removed by ICLE before significant secondary changes occur, vision can be preserved. In addition, it is now possible to restore excellent vision by replacing the luxated lens with a synthetic IOL.

Surgery of the orbit

Orbital surgery is performed infrequently but when necessary, requires detailed understanding of orbital anatomy and the probable biologic behavior and extent of the pathologic process affecting the orbit. Thorough preoperative characterization of an orbital disease allows the surgeon to develop a surgical strategy. Inaccurate or hasty preoperative localization, determination of extension, and diagnosis may result in selection of an inappropriate surgical approach or discretionary surgery when medical treatment is indicated. In most instances, diagnostic images (MR, CT, echography) should always be made and fine-needle aspiration be done before orbital surgery is performed. The choice of surgical approach or combination of approaches is determined primarily by the type, location, size, and extent of disease present. Extensive surgical exposure of the orbit is limited to centimeters or fractions of a centimeter because of the compact anatomy and tight confines of the orbital region. Careful tissue manipulation, surgical dissection, and postoperative assessment are necessary to preserve the globe and functional vision when orbital disease endangers function.

Surgery of the cornea

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.

Surgery for retinal detachment

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.

Surgery of the adnexa

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.

Phacoemulsification. Technology and fundamentals

The number one rule of phacoemulsification and aspiration cataract surgery is to know your machine. This chapter is designed to help the surgeon who is currently using phacoemulsification, or those who wish to understand more about technique, learn the basics and technology of the various types of phacoemulsification machines. Fluidics, pump design, handpiece mechanics, phacoemulsification needles, and fundamentals of phacoemulsification of cataracts will be reviewed.

Removal of a nasal polyp in a standing horse

Diagnosis and removal of a nasal polyp in a horse using standing chemical restraint and readily available equipment are described. Histopathology of the polyp and differential diagnoses are discussed.

Comparison and assessment of casting materials for use in small animals

This paper describes an investigation to evaluate the properties and uses of the different casting materials available for small animals. After a consideration of the properties that make an 'ideal cast', clinically relevant tests were performed on tubular casts of the various products. No single product demonstrated consistent superiority by all the criteria. All the products tested can be useful in a variety of situations, and suggestions for their uses are set out.

Early experience with the use of an interlocking nail for the repair of canine femoral shaft fractures

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.

Structural properties of interlocking nails, canine femora, and femur-interlocking nail constructs

Using standard material testing techniques (bending stiffness, torsional stiffness, and maximum torque to failure or yield torque), the structural properties of interlocking nails (IN), canine femora, and IN/femur constructs were determined. Specimens that were tested included: 6 and 8 mm diameter IN with 5 to 10 screw holes (n = 18), and intact canine femora (n = 10), which also, with an IN inserted, formed the intact construct (IC) group, (n = 10). Specimens in the IC group were first tested with an 8 mm diameter IN with zero screws, followed by one and two screws (4.5 mm diameter) in the proximal and distal femur. A fracture model construct (FMC), (n = 14), consisting of a transverse femoral osteotomy with a 3 mm gap, was used with either 6 mm or 8 mm IN. In the 6 mm FMC, one and two 3.5 mm screws were used sequentially in the proximal and distal femoral segment. In the 8 mm FMC, one and two 3.5 mm screws and one and two 4.5 diameter screws were used similarly. When bending forces were applied parallel to IN screw holes, mean IN stiffness was 20% less than with forces perpendicular to the holes (n = 18), (P < .05). Eight-millimeter IN were 220% stiffer in torsion and 270% stiffer in bending than 6 mm IN (P < .05). Six-millimeter IN had approximately 32% of the bending stiffness and torsional stiffness of intact femurs (P < .05). Eight-millimeter IN had 93% and 79% of the bending stiffness and torsional stiffness, respectively, of intact femurs. Intact femur constructs (8 mm IN with four, 4.5 mm screws) had 147% of the bending stiffness (P < .05), and similar torsional stiffness and maximum torque, as intact femora (P > .05). The mean values of 6 mm FMC with four screws (3.5 mm) were 21% and 33% in torsional stiffness and bending stiffness, respectively, of intact femora values. When tested in torsion, 8 mm FMC failed by bone fracture; 6 mm FMC, in contrast, underwent plastic deformation. In comparing FMC stabilized with an 8 mm IN with two screws (4.5 mm diameter) in each bone segment, to intact femurs, the maximum torque was similar, FMC torsional stiffness was 40% (P < .05), and FMC bending stiffness was 65% (P < .05). These 8 mm FMC percentages are comparable to human IN fracture model construct values, indicating that the 8 mm IN/four screw construct should provide adequate stabilization for many canine diaphyseal femoral fractures.

A mechanical evaluation of the resistance of various interfragmentary wire configurations to torsion

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.