Mechanical nociceptive thresholds in the axial skeleton of horses

REASONS FOR PERFORMING STUDY: An objective measure of neck, back and croup pain is needed in horses with musculoskeletal injuries, vague upper limb lameness or poor performance. OBJECTIVES: To establish mechanical nociceptive thresholds (MNTs) within the axial skeleton and evaluate the effects of subject status and ridden exercise. METHODS: Thirty-six mature horses (10 nonridden; 26 actively ridden) were used to assess MNTs evoked by a pressure algometer (PA) with a 1 cm2 rubber plunger tip at 62 midline and bilaterally symmetrical anatomical landmarks along the axial skeleton. Pressure was applied at a uniform rate of application until a local avoidance reaction was noted. The repeatability of 3 consecutive measurements was evaluated. Left-to-right comparisons and the effects of subject status and ridden exercise on MNTs were assessed. RESULTS: MNTs were repeatable and increased in a cranial-to-caudal gradient within the axial skeleton. Typically, there were no significant left-to-right differences. Within-horse variability was less than between-horse variability. Higher MNTs were measured in young, heavy, non-Thoroughbred, castrated males, and in horses that were ridden and actively exercised. CONCLUSIONS AND POTENTIAL RELEVANCE: PA provides an objective, noninvasive, and repeatable tool to measure mechanical nociception in horses. MNTs vary in horses with differing subject status and ridden exercise level.     

Pressure algometry to quantify muscle pain in racehorses with suspected sacroiliac dysfunction

REASONS FOR PERFORMING STUDY: Despite the prevalence of orthopaedic injuries to horses, there is no objective means of quantifying the intensity of musculoskeletal pain. HYPOTHESES: Mechanical nociceptive thresholds (MNT) can be measured repeatably by pressure algometry in horses and MNTs are correlated with both severity of clinical signs and subjective scores of muscle pain on palpation in horses with suspected sacroiliac dysfunction (SID). METHODS: The technique of pressure algometry and its repeatability was tested at 4 anatomical sites on either side of the thoracolumbar and pelvic region in 12 Thoroughbreds in training. In a second series of 15 racing Thoroughbreds, using a different set of landmarks, pain on palpation was assessed by pressure algometry. Horses were grouped based on clinical scores of SID as normal (n = 5), mild (n = 5), moderate (n = 4) and severe (n = 1) suspected SID and scored for muscle pain response by manual palpation. RESULTS: Pressure algometry was shown to be a repeatable measure of MNTs. Horses with suspected SID had significantly lower mean MNT when sites and horses were pooled and showed greater differences in mean algometer measurements between left and right sides, compared to control horses. A significant correlation was found between mean pressure algometry measurements and both suspected SID grade and muscle pain response on palpation. CONCLUSION AND POTENTIAL RELEVANCE: Horses with suspected SID displayed lower MNTs compared to control horses, especially in the pelvic region. This supports a potential role for pressure algometry in providing an objective means of quantifying musculoskeletal pain reflected as a reduced MNT associated with SID and its response to physiotherapy or other treatments.     

The Effect of Pulsed Electromagnetic Fields on Back Pain in Polo Ponies Evaluated by Pressure Algometry and Flexion Testing—A Randomized,Double-blind,Placebo-controlled Trial

This study assessed the therapeutic effect of pulsed electromagnetic fields (PEMF) on the backs of Polo ponies by measuring mechanical nociceptive thresholds (MNTs) and induced back movement. Twenty Polo ponies in regular training and competition were assigned to two groups. A double-blind, placebo-controlled, crossover field study with PEMF was performed, consisting of two 10-day therapy periods. At the beginning and end of each therapy period, the MNTs from 25 sites of the horses backs were assessed by pressure algometry (PA), and induced back movement was evaluated by flexion testing. Baseline MNTs were generally low, with means between 6.4 and 10.0 kg/cm². Significant changes in MNTs occurred nearly equally after both the PEMF and the placebo control treatments (at 5 of 25 or 6 of 25 sites, respectively) and without any regular pattern. Changes were evident, predominantly as decreased MNTs within and between treatment periods. Flexion testing revealed stiffness or avoidance in 19 of 20 horses. Results of the flexion testing showed an increased number of physiologic reactions at the end of both treatment periods compared with baseline values. The effect of PEMF on back pain and range of induced back movement could not be proven in this study. Although pretherapy values indicated the horses might have experienced back pain, all horses were still actively used in sport, and back pain might not have been severe enough to allow a significant effect to be demonstrated.     

The effects of chiropractic, massage and phenylbutazone on spinal mechanical nociceptive thresholds in horses without clinical signs

REASON FOR PERFORMING STUDY: Common methods used to treat back problems in horses need to be assessed objectively. OBJECTIVES: To measure spinal mechanical nociceptive thresholds (MNTs) and evaluate the effects of chiropractic, massage and phenylbutazone, compared with active and inactive control groups. METHODS: Baseline MNTs at 7 sites within the thoracolumbar and sacral regions were measured in 38 healthy mature horses exhibiting no clinical signs of lumbar pain. Horses were assigned to one of 3 treatment groups: instrument-assisted chiropractic treatment, therapeutic massage and phenylbutazone; or 2 control groups: ridden exercise (active control) or routine paddock turnout with no ridden exercise (inactive control). MNT measurements were repeated at 1, 3 and 7 days post treatment. The percentage change from baseline MNT values was calculated within groups. RESULTS: On Day 7, the median MNT had increased by 27, 12 and 8% in the chiropractic, massage and phenylbutazone groups, respectively. MNT changes of <1% were seen within the active and inactive control groups. CONCLUSIONS: Chiropractic treatment and massage therapy increased spinal MNTs within horses not exhibiting signs of lumbar pain. POTENTIAL RELEVANCE: Pressure algometry provides an objective tool to evaluate the effects of commonly used, but currently unproven treatment modalities on spinal MNTs. Future studies need to evaluate combined treatment effects and longer-term MNT changes in horses with documented back pain.     

Effect of Caudal Traction on Mechanical Nociceptive Thresholds of Epaxial and Pelvic Musculature on a Group of Horses With Signs of Back Pain

Direct muscular attachment from lumbar vertebrae to the caudal vertebrae of the tail suggests that caudal traction, also described as a tail pull, may affect lumbar vertebral segments and/or associated soft tissues in horses. Traction is a commonly used human manual therapy technique used for pain relief and anecdotally observed to relieve pain in horses. However, research is lacking validating the efficacy of manual caudal traction on the horse. The objective of this study was to determine if caudal traction has an effect on mechanical nociceptive thresholds (MNTs) in a group of horses with clinical signs of back pain. Pressure algometry was used to measure MNTs of five bilateral anatomical sites in the epaxial and pelvic musculature of 11 horses referred to physiotherapy because of clinical signs of back pain. Measurements were recorded both before and immediately after traction. A significant difference (P ≤ .05) was identified between mean before and after caudal traction algometry measurements in all described sites. The percentage of MNT increase was highest in the thoracic region (83%) compared with the lumbar (50%) and the pelvic (52.4%) regions. These results support an effect of caudal traction in increasing MNTs in the thoracolumbar and pelvic regions in horses. Further research to determine the clinical effect of this technique is warranted.     

Mechanical nociceptive thresholds within the pastern region of Tennessee Walking Horses

REASONS FOR PERFORMING STUDY: 'Soring' is the term used to describe the application of an irritant to the distal forelimbs of gaited horses with the sole intent of inflicting pain and inducing altered gait, illegally practiced in Tennessee Walking Horses. Objective methods for the detection of limb pain due to this practice are, however, lacking. OBJECTIVES: To assess whether Tennessee Walking Horses respond to manual pressures相似文献   

Lameness and poor performance in horses used for team roping: 118 cases (2000-2003)

OBJECTIVE: To determine the types of musculoskeletal problems that result in lameness or poor performance in horses used for team roping and determine whether these problems are different in horses used for heading versus heeling. DESIGN: Retrospective study. ANIMALS: 118 horses. PROCEDURE: Medical records of team roping horses that were evaluated because of lameness or poor performance were reviewed to obtain information regarding signalment, primary use (ie, head horse or heel horse), history, results of physical and lameness examinations, diagnostic tests performed, final diagnosis, and treatment. RESULTS: Among horses evaluated by lameness clinicians, the proportion with lameness or poor performance was significantly greater in horses used for heading (74/118) and lower in horses used for heeling (44/118) than would be expected under the null hypothesis. Most horses examined for poor performance were lame. A significantly greater proportion of horses used for heading had right forelimb lameness (26/74 [35%]), compared with horses used for heeling (7/44 [16%]). Horses used for heading had more bilateral forelimb lameness (18/74 [24%]), compared with horses used for heeling (4/44 [9%]). Horses used for heeling had more bilateral hind limb lameness (3/44 [7%]), compared with horses used for heading (0%). The most common musculoskeletal problems in horses used for heading were signs of pain limited to the distal sesamoid (navicular) area, signs of pain in the navicular area plus osteoarthritis of the distal tarsal joints, and soft tissue injury in the forelimb proximal phalangeal (pastern) region. Heeling horses most commonly had signs of pain in the navicular area, osteoarthritis of the metatarsophalangeal joints, and osteoarthritis of the distal tarsal joints. CONCLUSIONS AND CLINICAL RELEVANCE: Horses used for heading were most commonly affected by lameness in the right forelimb. Horses used for heeling had more bilateral hind limb lameness than horses used for heading.     

Arthrogenic lameness of the fetlock: synovial fluid markers of inflammation and cartilage turnover in relation to clinical joint pain

REASONS FOR PERFORMING THE STUDY: Joint pain is one of the most common causes of lameness in the horse but its pathogenesis is poorly understood. OBJECTIVES: To investigate which synovial fluid markers may be related to the presence of clinically detectable joint pain in the horse. METHODS: Concentrations of structural (CPII, C2C, GAG) and inflammatory markers (PGE2, LTB4, CysLTs, bradykinin and substance P) were measured in fetlock joint fluid from 22 horses in which lameness was localised to the fetlock region by perineural anaesthesia. Levels of these markers were then compared in horses that responded (n = 15) to those that did not (n = 7) to subsequent intra-articular anaesthesia (IAA). RESULTS: Of all markers analysed, only substance P levels were significantly higher (P = 0.0358) in synovial fluid of horses that showed a positive response to IAA compared to those with a negative response to IAA. Notably, while PGE2 levels were found to be elevated in all 22 lame horses compared to sound controls (P = 0.0025), they were not related to the response to IAA. CONCLUSIONS: While levels of PGE2 are elevated in synovial fluid of lame horses that respond to perineural anaesthesia, only substance P is related to joint pain as detected by the response to intra-articular anaesthesia. POTENTIAL RELEVANCE: Substance P is associated with clinically detectable joint pain in the horse. Elevated levels of PGE2 in fetlock-lame horses, regardless of their response to IAA, indicate that either this mediator does not reflect intra-articular pain or that IAA might have limitations in differentiating between intra- and peri-articular sources of pain. Either way, a negative response to IAA may not exclude intra-articular pathology.     

Effects of Low-Level Laser Therapy and Chiropractic Care on Back Pain in Quarter Horses

Low-level laser therapy has been used clinically to treat musculoskeletal pain; however, there is limited evidence available to support its use in treating back pain in horses. The objective of this study was to evaluate the clinical effectiveness of low-level laser therapy and chiropractic care in treating thoracolumbar pain in competitive western performance horses. The subjects included 61 Quarter Horses actively involved in national western performance competitions judged to have back pain. A randomized, clinical trial was conducted by assigning affected horses to either laser therapy, chiropractic, or combined laser and chiropractic treatment groups. Outcome parameters included a visual analog scale (VAS) of perceived back pain and dysfunction and detailed spinal examinations evaluating pain, muscle tone, and stiffness. Mechanical nociceptive thresholds were measured along the dorsal trunk and values were compared before and after treatment. Repeated measures with post-hoc analysis were used to assess treatment group differences. Low-level laser therapy, as applied in this study, produced significant reductions in back pain, epaxial muscle hypertonicity, and trunk stiffness. Combined laser therapy and chiropractic care produced similar reductions, with additional significant decreases in the severity of epaxial muscle hypertonicity and trunk stiffness. Chiropractic treatment by itself did not produce any significant changes in back pain, muscle hypertonicity, or trunk stiffness; however, there were improvements in trunk and pelvic flexion reflexes. The combination of laser therapy and chiropractic care seemed to provide additive effects in treating back pain and trunk stiffness that were not present with chiropractic treatment alone. The results of this study support the concept that a multimodal approach of laser therapy and chiropractic care is beneficial in treating back pain in horses involved in active competition.     

Effect of local analgesia on movement of the equine back

REASONS FOR PERFORMING STUDY: Diagnostic infiltration of local anaesthetic solution is commonly used in cases of equine back pain. Evaluation is subjective and it is not known how local analgesia of the back affects horses without clinical signs of back pain. OBJECTIVES: To evaluate the effect of infiltration of local anaesthetics on the movement of the back in horses without clinical signs of back pain, and to evaluate the usefulness of kinematic studies as an objective and quantitative tool in evaluating local analgesia in clinical practice. METHODS: The kinematics of the back in 10 clinically sound horses were measured on 2 occasions at walk and trot before and after injections with mepivacaine and sodium chloride around the interspinous spaces between T16 and L2. The kinematics were compared between the 2 occasions before injections and before and after each injection. RESULTS: The range of motion (ROM) for dorsoventral flexion-extension (FE) of the back was increased significantly in all measured segments other than T10 at walk, as was lateral bending (LB) at T10, L3 and L5 after injection of mepivacaine. For lateral excursion (LE), total movement increased at all measured segments. At trot the only affected segment was L3, where the injection with mepivacaine decreased the ROM for FE. After injection of sodium chloride the ROM for FE increased at T13 and T17 at walk. Lateral bending and LE were not affected at walk. At trot, LB increased at L3 and L5. CONCLUSIONS AND POTENTIAL RELEVANCE: Diagnostic infiltration of local anaesthetic solution affects the function of the back in clinically sound horses, which must be considered when interpreting the use of this clinical aid in assessing clinical cases of back dysfunction. Kinematics can qualitatively and quantitatively evaluate the effect of local analgesia of the back.     

Locomotor characteristics of horses with navicular disease

OBJECTIVE: To determine whether force-plate evaluation of horses with navicular disease would reveal an abnormal gait that persists despite loss of sensation to the palmar foot region, which may predispose such horses to navicular disease. ANIMALS: 17 clinically normal Thoroughbreds and 8 Thoroughbreds with navicular disease. PROCEDURE: Data on ground reaction forces were obtained in trotting horses, using a force plate. Force-time curve variables for clinically normal horses were derived from 4 points at the beginning and 4 points at the end of the vertical and craniocaudal horizontal plots. Principal component analysis was undertaken separately on beginning-of-stride and end-of-stride data, and the first 2 components were represented graphically. Rotation matrices were applied to equivalent data for horses with navicular disease before and after disruption of sensation by administration of a palmar digital nerve blockade. RESULTS: Prior to nerve block, horses with navicular disease differed significantly from normal horses for beginning-of-stance phase and end-of-stance phase variables. After nerve block, horses with navicular disease maintained the same significant differences from clinically normal horses only for variables at the beginning-of-stance phase. CONCLUSIONS AND CLINICAL RELEVANCE: Horses with navicular disease have abnormal limb-loading force patterns that are not altered by loss of sensation in the palmar region. These abnormal patterns were detected in a horse without navicular disease. Some horses are predisposed to navicular disease as a result of an inherent abnormal gait pattern. Analysis of gait patterns could be used for detection and appropriate management of horses susceptible to development of navicular disease.     

Arthrocentesis of the temporomandibular joint in adult horses

OBJECTIVE: To develop a method for arthrocentesis of the temporomandibular joint in adult horses. ANIMALS: 7 equine cadaver heads and 6 clinically normal adult horses. PROCEDURE: Fluoroscopy, contrast radiography, and computed tomography were used on cadaver specimens to locate the temporomandibular joint, identify externally palpable landmarks for joint access, guide needle placement into the joint, and illustrate regional anatomy. The arthrocentesis technique was performed on 6 live healthy adult horses to determine efficacy and safety of this procedure. RESULTS: Externally palpable structures were identified as landmarks for temporomandibular arthrocentesis, including the lateral border of the condylar process of the mandible, the zygomatic process of the temporal bone, and the lateral pericapsular fat pad. Arthrocentesis was successful in all 6 joints in the live horses, and no complications developed. CONCLUSIONS AND CLINICAL RELEVANCE: The technique identified will improve the ability to examine and treat the temporomandibular joint in horses.     

Doppler ultrasonographic features of thoracic limb arteries in clinically normal horses

OBJECTIVES: To determine blood flow velocities and indices from spectral waveforms obtained by use of Doppler ultrasonography of thoracic limb arteries of horses and to assess interobserver and patient variability associated with the technique. ANIMALS: 9 clinically normal adult horses. PROCEDURE: Left thoracic limb arteries of 8 nonsedated horses were examined at 5 sites by use of pulsed-wave Doppler ultrasonography to determine a range of values for peak systolic, end diastolic, and mean velocities and resistive and pulsatility indices. Interobserver and patient variabilities were determined by 2 operators repeating similar measurements on 1 horse 8 times at weekly intervals. RESULTS: A range of values for each variable measured at the 5 selected sites was obtained. For each variable, strong positive correlations (R > or = 0.7) were detected for > 70% of the site-to-site comparisons made (excluding the coronary band). Among horses, resistive index varied least, whereas over time, mean velocity varied least. Waveform characteristics were consistent with resistive (n = 5) or nonresistive (4) patterns. In the single-horse experiment, waveform characteristics were consistent throughout the 8 weeks, and operator effects were not detected. CONCLUSIONS AND CLINICAL RELEVANCE: Doppler ultrasonography of no one site resulted in more reliable measurements of blood flow characteristics in thoracic limb arteries of horses. Mean velocity and resistive index were the least variable measurements made. Pulsed-wave Doppler ultrasonography may be a useful technique for evaluating diseases that alter normal thoracic limb arterial blood flow in horses.     

Disease-specific changes in equine ground reaction force data documented by use of principal component analysis.

OBJECTIVE: To assess the force plate as a diagnostic aid in equine locomotor abnormalities, particularly for abnormalities such as navicular disease that do not have specific diagnostic criteria. ANIMALS: 17 Thoroughbreds without observable locomotor abnormalities (group A), 6 Thoroughbreds with superficial digital flexor tendon injury (group B), and 8 Thoroughbreds with navicular disease (group C). PROCEDURE: Using a force plate, ground reaction force patterns were recorded at the trot. Peak limb vertical force and force/time curve parameters were derived from 4 identifiable points at the beginning and end of vertical and craniocaudal horizontal plots. Principal component analysis (PCA) of group-A data was undertaken on beginning and end of stride data, and the first 2 components were represented graphically. The PCA rotation matrices were applied to equivalent data for horses of groups B and C. RESULTS: Asymmetry of peak vertical force (PVF) could not be differentiated among groups A, B, and C. Values for group-B horses, however, were significantly outside mean group-A values on the PCA plot for beginning of stride phase variables. Group-B data were within the group-A range for end of stride phase variables. Values for group-C horses were significantly outside the group-A range for beginning of stride phase variables and were outside mean group-A values for end of stride phase variables. CONCLUSIONS: PCA of force/time data provides a sensitive method to evaluate the force/time curve associated with 2 specific injury/disease processes. CLINICAL RELEVANCE: Horses alter weight-bearing in biomechanically distinct ways, thus creating potential for the force plate to become an important diagnostic and prognostic tool.     

Laparoscopic intestinal exploration and full-thickness intestinal biopsy in standing horses: a pilot study

OBJECTIVE: To assess a laparoscopic technique for equine intestinal biopsy. STUDY DESIGN: Experimental study. ANIMALS: Seven adult horses. METHODS: Food but not water was withheld for 36 hours before laparoscopy. In 3 horses (group A) standing, right laparoscopic access to different small intestinal segments was compared with ventral median celiotomy access. Inaccessible segments were identified at necropsy. In 4 horses (group B), the feasibility of obtaining full-thickness duodenal and cecal biopsies and any associated morbidity were evaluated. Biopsy specimens were collected during standing right laparoscopy using a 2-step procedure and intracorporeal suturing technique, and abdominal lavage was performed. Horses were monitored clinically and by abdominal fluid cytology and microbial culture, and repeat laparoscopy was performed on day 6. RESULTS: Standing right flank laparoscopy provided good observation of small intestinal segments and enabled manipulation of all but 15-20 cm of the duodenum and approximately 40 cm more ileum compared with ventral median celiotomy. Group B horses had no complications, no adhesions, and no bacterial growth from peritoneal fluid samples. None of the horses had signs of abdominal pain. CONCLUSION: A 2-stage intestinal biopsy technique performed during standing, right flank laparoscopy may be a safe alternative to exploratory celiotomy and biopsy in normal horses. CLINICAL RELEVANCE: Right flank laparoscopy allows biopsy of intestinal segments including duodenum and 50% more of the ileum than is accessible by ventral median celiotomy. This technique should be evaluated in clinical patients.     

Frequency of musculoskeletal injuries and risk factors associated with injuries incurred in Quarter Horses during races.

OBJECTIVE: To determine the frequency and anatomic location of musculoskeletal injuries incurred by Quarter Horses during races and to compare data from injured horses and matched control horses. DESIGN: Matched case-control study. ANIMALS: 97 Quarter Horses that sustained a musculoskeletal injury during races and 291 horses from the same races that were not injured. PROCEDURE: Data examined included racing history, race-entrant characteristics, racing events determined by analysis of videotapes of races, and, when performed, results of prerace physical inspections. Data for injured horses were compared with data for control horses, using conditional logistic regression. RESULTS: Incidence of a catastrophic injury among Quarter Horses during races was approximately 0.8/1,000 race starts, whereas incidence of musculoskeletal injury during racing was approximately 2.2/1,000 race starts. Odds of musculoskeletal injury were approximately 8 times greater among horses assessed to be at increased risk of injury on the basis of results of prerace physical inspection than for horses not considered to be at increased risk of injury. Evidence was lacking that 2-year-old horses were at increased risk of injury or that sex influenced the risk of injury among Quarter Horses during races. CONCLUSIONS AND CLINICAL RELEVANCE: Incidence of racing injury among Quarter Horses appears to be lower than that observed among Thoroughbreds. Regulatory veterinarians can identify horses at increased risk of injury on the basis of prerace physical inspection, indicating that these inspections could be used to reduce the risk of injury during races.     

Clinical evaluation of the effects of immobilization followed by remobilization and exercise on the metacarpophalangeal joint in horses

OBJECTIVES: To evaluate clinical effects of immobilization followed by remobilization and exercise on the metacarpophalangeal joint (MPJ) in horses. ANIMALS: 5 healthy horses. PROCEDURE: After lameness, radiographic, and force plate examinations to determine musculoskeletal health, 1 forelimb of each horse was immobilized in a fiberglass cast for 7 weeks, followed by cast removal and increasing amounts of exercise, beginning with hand-walking and ending with treadmill exercise. Lameness examination, arthrocentesis of both MPJ, single-emulsion radiographic examination, nuclear scintigraphic examination, ground-reaction force-plate analysis, and computed tomographic examination were done at various times during the study. RESULTS: All horses were lame in the immobilized MPJ after cast removal; lameness improved slightly with exercise. Force plate analysis revealed a significant difference in peak forces between immobilized and contralateral limbs 2 weeks after cast removal. Range of motion of the immobilized MPJ was significantly decreased, and joint circumference was significantly increased, compared with baseline values, during the exercise period. Osteopenia was subjectively detected in the immobilized limbs. Significant increase in the uptake of radionucleotide within bones of the immobilized MPJ after cast removal and at the end of the study were detected. Loss of mineral opacity, increased vascular channels in the subchondral bone, and thickening within the soft tissues of the immobilized MPJ were detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that 8 weeks of enforced exercise after 7 weeks of joint immobilization did not restore joint function or values for various joint measurements determined prior to immobilization.     

Determination and use of mechanical nociceptive thresholds of the thoracic limb to assess pain associated with induced osteoarthritis of the middle carpal joint in horses

OBJECTIVES: To establish reference mechanical nociceptive threshold (MNT) values of the equine thoracic limb and to assess the use of MNT values to detect pain associated with induced osteoarthritis in the middle carpal joint. ANIMALS: 24 adult horses. PROCEDURES: MNT values were evoked by a pressure algometer at 17 sites within each thoracic limb during 2 baseline sessions conducted an average of 5 days apart. Effects of age, sex, weight, and wither height on MNT values were assessed separately for each site. Tolerance of horses to the procedure was graded subjectively and correlated with MNT values. Synovitis and osteoarthritis were induced arthroscopically in the middle carpal joint of 1 randomly selected thoracic limb. The opposite limb served as a sham-operated control limb. Mechanical nociceptive threshold values were recorded weekly and correlated with clinical, radiographic, and necropsy scores measured over 10 weeks. Lower MNT values corresponded with increased pain, whereas higher MNT values indicated reduced pain. RESULTS: A gradual increase in MNT values was detected from proximal-to-distal sites of the thoracic limbs. High MNT values were recorded for geldings and tall horses. In general, tolerance to procedure scores was positively correlated with overall pooled MNT values within each thoracic limb. From 2 to 6 weeks after surgery, the osteoarthritic limb had significantly reduced MNT values within the carpal region. The osteoarthritic limb also had significant changes in clinical examination, radiographic, and necropsy scores, which were poorly correlated with MNT values. CONCLUSIONS AND CLINICAL RELEVANCE: Pressure algometry provided objective assessment of nociception of the thoracic limb; however, MNT values were poorly correlated with clinical variables used to assess osteoarthritis.     

Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 2: Short-term complications

REASONS FOR PERFORMING STUDY: Few studies have assessed short- and long-term complication rates of horses following surgical treatment of colic, a potentially fatal condition. Complications can lead to patient discomfort and increased costs; knowledge of predisposing factors may help to reduce complication rates. OBJECTIVES: To document and analyse short-term complications in 300 horses undergoing colic surgery, and to assess some of the possible predisposing factors. METHODS: History, clinical findings, surgical findings and procedures, and post operative treatments of 300 consecutive surgical colic cases (1994-2001) were reviewed. Comparisons among groups of discrete data were made using chi-squared or Student's t tests as appropriate. RESULTS: Short-term complications in 227 horses following a single laparotomy included colic/pain (28.2%), incisional drainage or infection (26.9%), post operative ileus (13.7%), severe endotoxaemic shock (12.3%), jugular thrombophlebitis (7.5%), septic peritonitis (3.1%) and colitis/diarrhoea (2.2%). Horses with small bowel obstruction had a higher rate of post operative ileus than those with large bowel obstruction. Rates of post operative pain and shock were higher in horses with small colon rather than large colon obstruction, and in those that had an ischaemic rather than a simple obstruction. The rate of wound complications increased with increasing total plasma protein concentration at admission. Horses that had a repeat laparotomy had a higher rate of wound complications compared to those that had a single laparotomy. Application of a stent bandage was associated with a higher rate of wound complications than if no stent was applied; however, application of an incise drape over the wound for recovery was associated with a lower rate of wound complications than for horses that had no protective covering of the wound. CONCLUSIONS: The most common short-term post operative complications following colic surgery were pain, incisional drainage, ileus, endotoxaemiac shock and jugular thrombophlebitis. Some factors that appeared to predispose to these complications were identified. Although many of these factors related to the underlying disease process, a number of factors, including surgical techniques, were identified that might be amenable to modification. POTENTIAL RELEVANCE: Prospective studies to assess the effects of modifying these factors on survival rates should be performed.