Equine field practice commonly requires short- to medium-term anesthesia being induced in horses for either minor surgical or diagnostic procedures or for urgent medical care in emergency situations. Performing a general anesthetic in the field further increases the risk associated with equine anesthesia which already is high when compared with small animal or human anesthesia, even under best of hospital conditions. For this reason, cases for field anesthesia should be carefully selected and appropriate anesthesia protocols chosen by taking into account the peculiar setting of the location, the physical condition of the patient, and the specific circumstances of the surgical, diagnostic, or other procedures planned. This review provides an overview of the anesthetic techniques suitable for field anesthesia. First, the approach to the equine patient under field as compared with hospital conditions is addressed, followed by a detailed discussion of common field anesthetic protocols reported for use in adult horses and in foals. Finally, anesthetic protocols suitable for horses suffering injuries during or immediately after maximum exercise are addressed.
Vascular disorders play an important role in male infertility. Various modalities of ultrasound examination can be applied to evaluate testicular vasculature and to objectively measure numerous parameters of testicular perfusion. This paper describes techniques of ultrasound examination of testicular vasculature in the stallion, using gray-scale, color, and power Doppler ultrasound. Results of studies on the normal vascular anatomy in the stallion and its variations, the methods of obtaining most optimal measures of testicular perfusion, and the effects of the physiological and pharmacological factors on testicular blood flow are reviewed. There is a growing body of evidence that evaluation of testicular vasculature has a tremendous clinical relevance and should be included in the diagnostic workup of scrotal diseases.
Magnetic resonance (MR) imaging is the gold-standard imaging modality for diagnosing tendon and ligament pathology. MR is capable of detecting lesions that are not visible with other imaging modalities. Pathologic changes in tendons and ligaments are seen on MR as changes in size, shape, and/or signal intensity of the affected structure. All tendons and ligaments have individual characteristics and variations in normal appearance. This chapter describes the normal MR appearance of the tendons and ligaments of the distal limb, as well as discussing the ways in which damage to individual tendons and ligaments affects how they appear on MR images.
A variety of surgical procedures are available to ameliorate the discomfort of tendonitis or desmitis, treat the original cause, or enhance healing. The following current techniques are described: neurectomy of the deep penetrating branch of the lateral plantar nerve, suspensory ligament fasciotomy, desmotomy of the palmar/plantar annular ligament via an extrasynovial approach and using arthroscopic guidance, desmotomy of the accessory ligament of the superficial digital flexor tendon (AL-SDFT, proximal check ligament) via the direct medial approach and via arthroscopic guidance, and desmotomy of the accessory ligament of the deep digital flexor tendon (AL-DDFT, distal check ligament).
Pain is a subjective and complex multidimensional sensory experience that usually occurs as a result of tissue trauma. It is generated after extensive neuronal signal processing within the brain following the activation of peripheral high-threshold sensory receptors (nociceptors), which send nerve impulses from the periphery to the central nervous system. Pain resulting from stimulation of nociceptors can be considered a physiological phenomenon as it helps minimizing further tissue damage by activating reflex withdrawal mechanisms and increasing behavioral, autonomical, and neurohumeral responses that are aimed at maintaining body integrity, preventing further tissue injury and promoting healing. However, if persistent, mechanisms described as peripheral and/or central sensitization alter the pain experience in the patient, transforming physiological pain into maladaptive pain, which is dissociated from the original noxious stimuli or healing process. Thus, maladaptive pain must be considered a pathological condition in and of itself. It is often responsible for persistent discomfort and stress of the horse, which can lead to abnormal behaviors, reduced quality of life and, if uncontrolled, distress and eventually humane destruction of the animal. This article intends to give an overview of the anatomic sides as well as physiological and pathophysiological processes involved in the generation, conduction, and integration of nociceptive signals and presents a pain classification scheme that is more indicative of the neural mechanisms underlying pain phenomena and thus provides the veterinarian with a better direction of how to approach pain therapeutically.
