Ultrasonographic abnormalities detected in the sacroiliac area in twenty cases of upper hindlimb lameness

REASONS FOR PERFORMING STUDY

The pelvis is covered with extensive musculature and often presents a challenge in diagnostic imaging. Ultrasonography provides diagnostic information about soft tissue, articular cartilage and bone surfaces, although little information exists about the normal ultrasonographic appearance of the equine sacroiliac region.

OBJECTIVES

To determine the clinical applicability of ultrasonographic examination in horses with sacroiliac pain.

METHODS

Horses presented to the University of Minnesota Veterinary Teaching Hospital for hindlimb lameness were evaluated and lower limb lameness was ruled out with examination and local anaesthesia. Twenty cases were diagnosed with sacroiliac pain, characterised by response to palpation over the tuber sacrale. Seven of the 20 had visible asymmetry of the tuber sacrale. Ultrasonography was performed percutaneously and per rectum. Structures imaged were measured and compared to normal reference measurements. Other methods used to confirm diagnoses included thermography, scintigraphy and radiology.

RESULTS

All 20 cases with sacroiliac pain showed ultrasonographic abnormalities of the sacroiliac area. Abnormalities were detected in the dorsal sacroiliac ligaments. Ligament size was significantly different from the normal ranges (P < 0.01). Malalignment of the sacroiliac area and sacral fractures were also imaged.

CONCLUSIONS

Ultrasonography of the sacroiliac region aided diagnosis of ligament damage and displacement of bone surfaces; and may aid in monitoring the progression of healing.

POTENTIAL RELEVANCE

Diagnostic ultrasound is readily available to most practitioners. Therefore the findings of this study show that diagnosis of sacroiliac injuries is possible in the field.

Detailed ultrasonographic mapping of the pelvis in clinically normal horses and ponies

OBJECTIVE

To map the equine pelvis using ultrasonography, validated by use of computed tomography (CT), magnetic resonance imaging (MRI), and measurements of frozen cadaver slices.

ANIMALS

6 ponies and 6 horses.

PROCEDURE

Ultrasonographic examination of the pelvis was performed on 6 clinically normal ponies. Measurements were obtained for imaged structures. Computed tomography, MRI, and measurements of frozen sections were performed after death and used to verify measurements. Linear regression determined the degree of correlation between measurements obtained ultrasonographically and the other modalities. Six clinically normal horses were then examined by use of ultrasonography. For each structure measured mean, SD, and range were calculated.

RESULTS

Data obtained from ponies revealed high correlations between ultrasonographic findings and those of CT, MRI, and frozen section measurements (r2 = 0.97, r2 = 0.99, and r2 = 0.99, respectively). Differences between structures measured on each side of the pelvis were not significant. Variation in size of structures was not associated with weight of horses. A correlation was not found between weight of horses and ponies and size of structure.

CONCLUSIONS AND CLINICAL RELEVANCE

Ultrasonography can be used to accurately measure and evaluate the musculoskeletal structures of the pelvis of horses. The use of CT, MRI, and measurements of frozen sections provided a means of validating the ultrasonographic measurements. Reference range values determined in our study can be used to evaluate horses with suspected pelvic disease.

Percutaneous ultrasound-guided pyelography aided diagnosis of ectopic ureter and hydronephrosis in a 3-week-old filly

Ultrasound-guided percutaneous pyelography has previously been used in dogs to diagnose ectopic ureter. To the authors' knowledge its use has never been reported in the horse. This paper reports the technique used in a three-week-old filly with a suspected ectopic ureter. Pyelography can be performed under sedation and is a relatively simple, safe procedure. The technique enables assessment of individual renal function through collection and analysis of urine from each renal pelvis.

Diagnostic thermography

Thermography is a practical aid in the clinical evaluation of the equine patient. It is particularly germane to the evaluation of lameness. This modality specifically increases the accuracy of diagnosis. Thermography is the pictorial representation of skin temperature. The technique involves the detection of infrared radiation, which can be directly correlated to blood flow. To be accurate, thermography must be performed in a controlled area free of drafts. The area should be protected from sunlight to avoid erroneous heating of the skin, and the horse's hair length should be uniform. Thermography detects heat before it is perceptible during routine physical examination and thus is useful for the early detection of laminitis, stress fractures, and tendinitis. It offers a noninvasive means of evaluating the blood supply to an injured region and represents one of the only reliable noninvasive means to evaluate blood flow to the foot of the horse. Thermography is also useful for the early identification of stress injuries to the contralateral limb of convalescing orthopedic patients. Thermography is an excellent adjunct to clinical examination as well as being complementary to other imaging techniques such as radiology, ultrasonography, and scintigraphy.

An in vitro biomechanical comparison of interlocking nail constructs and double plating for fixation of diaphyseal femur fractures in immature horses

OBJECTIVE

To compare the biomechanical properties of intact immature horse femurs and 3 stabilization methods in ostectomized femurs.

ANIMAL OR SAMPLE POPULATION

Eighteen pairs of femurs from immature horses aged 1 to 15 months, and weighing 68 to 236 kg.

METHODS

Thirty-four immature horse femurs were randomly assigned to 1 of 5 test groups: 1) interlocking intramedullary nail (IIN) (n = 6); 2) IIN with a cranial dynamic compression plate (I/DCP) (n = 6); 3) 2 dynamic compression plates (2DCP) (n = 8); 4) intact femurs tested to failure in lateromedial (LM) bending (n = 6); and 5) intact femurs tested to failure in caudocranial (CaCr) bending (n = 8). Mid-diaphyseal ostectomies (1 cm) were performed in all fixation constructs. Biomechanical testing consisted of 4 nondestructive tests: CaCr bending, LM bending, compression, and torsion, followed by bending to failure. All groups were tested to failure in LM bending with the exception of 1 group of intact femurs tested to failure in CaCr bending. Stiffness and failure properties were compared among groups.

RESULTS

The 2DCP-femur construct had greater structural stiffness in nondestructive bending than the IIN-femur construct in either LM or CaCr bending, and the I/DCP-femur construct in LM bending. Only the I/DCP and 2DCP fixations were similar to intact bone in nondestructive-bending tests. In addition, the 2DCP-femur construct had greater structural and gap torsional stiffness than the I/DCP-femur construct, and greater gap torsional stiffness than the IIN-femur construct. However, all of the fixation methods tested, including the 2DCP-femur construct, had lower structural stiffness in torsional loading compared with intact bone. No significant differences in structural stiffness were found between intact bones and femur constructs tested nondestructively in compression. In resistance to LM bending to failure, the 2DCP-femur construct was superior to the IIN-femur construct, yet similar to the I/DCP-femur construct. Also, evaluation of yield and failure loads revealed no significant differences between intact bone and any of the femur constructs tested to failure in LM bending.

CONCLUSIONS

In general, the 2DCP-femur construct provided superior strength and stiffness compared with the IIN and I/DCP-femur constructs under bending and torsion.

CLINICAL RELEVANCE

Double plating of diaphyseal comminuted femoral fractures in immature horses may be the best method of repair, because in general, it provides the greatest strength and stiffness in bending and torsion.

Arthroscopic surgery in a reticulated giraffe (Giraffa camelopardalis reticulata)

An 8-mo-old captive male reticulated giraffe (Giraffa camelopardalis reticulata) developed an acute lameness (grade IV/V) of the right forelimb, with swelling of the metacarpophalangeal joint. A traumatic injury was suspected based on clinical, radiographic, and arthroscopic evaluation. Several abnormalities were identified arthroscopically, including synovitis, cartilage damage, and an osteochondral fragment. Medial collateral ligament damage was also suspected based on radiographic evaluation. Arthroscopy provided a means of diagnosis and treatment of the abnormalities identified. The lameness in this giraffe resolved within 6 wk following arthroscopic surgery.

Adrenergic, cholinergic, and nonadrenergic-noncholinergic intrinsic innervation of the jejunum in horses

OBJECTIVE

To determine the major neurotransmitters that regulate contractile activity in the jejunum of horses.

SAMPLE POPULATION

Jejunal specimens from 65 horses without gastrointestinal tract lesions.

PROCEDURE

Jejunal smooth muscle strips, oriented in the plane of the circular or longitudinal muscular layer, were suspended isometrically in muscle baths. Neurotransmitter release was induced by electrical field stimulation (EFS) delivered at 30 and 70 V intensities and at various frequencies on muscle strips maintained at low or high muscle tone. To detect residual nonadrenergic-noncholinergic neurotransmission, the response of muscle to EFS in the presence of adrenergic and cholinergic blockade was compared with the response in the presence of tetrodotoxin.

RESULTS

Atropine (ATR) decreased the contractile response of muscle strips to EFS under most conditions. However, ATR increased the contractile response of high-tone circular muscle. Adrenergic blockade generally increased the muscle responses to 30 V EFS and in high-tone longitudinal muscle but decreased contractile responses in high-tone circular muscle. Tetrodotoxin significantly altered the responses to EFS, compared with adrenergic and cholinergic receptor blockade.

CONCLUSIONS

Acetylcholine and norepinephrine appear to be important neurotransmitters regulating smooth muscle contractility in the equine jejunum. They induce contraction and relaxation, respectively, in most muscle preparations, although they may cause opposite effects under certain conditions. In addition, nonadrenergic-noncholinergic excitatory and inhibitory influences were detected.

CLINICAL RELEVANCE

Acetylcholine or norepinephrine release within the myenteric plexus of horses may alter gastrointestinal motility.

Endoscopy of the intertubercular bursa in horses

Forelimbs from 3 anesthetized horses and 16 fresh cadaver horses were used to describe the endoscopic anatomy of the intertubercular bursa and outline the surgical portals that provide the greatest access to structures within the bursa. A lateral arthroscopic portal was made proximal to the deltoid tuberosity of the humerus into the distal bursal recess. A second portal was created proximal to the humeral tubercles that entered the proximal bursal space. These approaches provided consistent viewing and instrument access to the lateral intertuberal groove, the greater and intermediate humeral tubercles, and the synovial membrane of the proximal and distal bursal recesses. The intermediate tubercle and heavy muscle mass restricted access to the medial intertuberal groove and lesser tubercle. This technique may provide a less invasive alternative to bursotomy in the surgical management of selected horses with intertubercular bursitis. Clinical applications include cartilage debridement, fragment removal, partial synovectomy, and high-volume lavage.

Treatment of a comminuted frontal-plane fracture of the distal phalanx in a horse

Successful treatment of a comminuted frontal plane fracture of the distal phalanx in a horse is described. The bone fractured through the solar canal, close to the insertion of the deep digital flexor tendon. A hoof case was used to reduce bending and tensile stresses on the solar surface by limiting expansion of the hoof wall during weightbearing. In addition, the heel was elevated, using 3 degrees wedge pads incorporated within the hoof cast, to reduce distraction at the fracture site caused by the pull of the deep digital flexor tendon. Two casts were used over a 4-month period. Complete radiographic healing of the fracture was evident 4 months after injury. At this time the horse was lame at the trot. The owner reported the horse to be sound 7 months after injury. Reexamination 12 months after injury revealed a clinically normal foot and no lameness.

Influence of adrenergic and cholinergic mediators on the equine jejunum in vitro

OBJECTIVE

To characterize the response of equine jejunal smooth muscle to adrenergic and cholinergic mediators.

DESIGN

Evaluation of myogenic responses, using an in vitro model.

SAMPLE POPULATION

Intestinal tissues were obtained from horses without gastrointestinal tract disorders or systemic disease.

PROCEDURE

Baseline myogenic tone and amplitude and frequency of contraction were determined for suspended jejunal muscle strips. The level of adrenergic and cholinergic regulation was assessed, using atropine and adrenoceptor antagonists. The response of the muscles to norepinephrine was characterized, using adrenergic blockade and alpha- and beta-agonists.

RESULTS

Adrenergic and cholinergic blockade had minimal effect on baseline myogenic activity. However, alpha 1- and beta 2-agonists induced significant (P < 0.05) decreases in the amplitude and frequency of contraction. Surprisingly, alpha 2-agonists caused an increase in the contraction amplitude of longitudinal muscle fibers (neurogenic in origin). Change in circular muscle activity was not induced by alpha 2-agonists. Norepinephrine induced a similar selective response and was inhibited by yohimbine.

CONCLUSIONS

Baseline jejunal activity appears to be myogenic in origin and can function independently of sympathetic and parasympathetic input. However, intestinal smooth muscle can be affected by adrenergic agonists and potentially by increased concentrations of circulating catecholamines. Norepinephrine may act by altering the activity of other neurotransmitters. Differing responses between circular and longitudinal muscle fibers indicates a need to evaluate both components.

CLINICAL RELEVANCE

Selective alpha 2-agonists may be potentially useful for motility modification of the equine jejunum. Therapeutic use of adrenergic blockade will be effective only in cases of increased adrenergic stimulation.

Aneurysm of the cranial mesenteric artery in a cow

Exploratory laparotomy of an adult dairy cow, examined because of acute signs of persistent abdominal pain, revealed a firm pulsatile mass with associated fremitus just distal to the origin of the cranial mesenteric artery. The cow died acutely 2.5 days after surgery. A dilated, thin-walled, sacculated aneurysm, which had ruptured, was located along the proximal portion of the cranial mesenteric artery. It was postulated that the aneurysm developed secondary to structural defects in the arterial wall, but caused no clinical signs until enlargement and local tissue stretching or circulatory disturbances caused intestinal ischemia, resulting in abdominal pain. Aneurysms of visceral arteries in cattle should be considered as another differential diagnosis for signs of abdominal pain after more common causes such as severe bloat, mesenteric root volvulus, intussusception, cecal dilatation/volvulus, and uterine torsion have been excluded.

Hepatic lobe torsion as a cause of colic in a horse

A 14-year-old Arabian gelding was examined for colic. An exploratory celiotomy was subsequently performed and the left lobe of the liver was found to be twisted. The lobe was resected using a TA-90 surgical stapling instrument. Histologic examination of the resected liver indicated portal vein and sinusoid dilation and congestion with blood. There were focal areas of necrosis and bacterial cocci and rods throughout the section. The histologic findings were consistent with hepatic lobe torsion. After surgery, the horse was treated with broad spectrum antibiotics, anti-inflammatory drugs, heparin, and intravenous fluids. The horse recovered without complications, although serum liver enzymes remained elevated for more than 1 week after surgery. Seven months after surgery the horse showed no adverse affects from the disease.

Nonsurgical treatment of cubital subchondral cyst-like lesions in horses: seven cases (1983-1987)

Subchondral cyst-like lesions of the cubital joint were diagnosed in 7 horses at the teaching hospital between 1983 and 1987. Diagnosis of the lesions was made by administration of intra-articular local anesthesia and/or radiographically. Initial treatment for all horses consisted of stall rest for 60 to 90 days. In addition, 2 horses were administered sodium hyaluronate intra-articularly, 1 horse was given injections of polysulfated glycosaminoglycans IM, and 1 horse was given phenylbutazone orally. Follow-up information was compiled 6 weeks to 4 years after initial examination. At the time of follow-up inquiry, 6 horses were sound for intended use and only 1 horse became lame when exercised. A logical approach to choice of surgical or nonsurgical treatment is proposed on the basis of these findings and those reported in the literature.

Thermography as an aid to the clinical lameness evaluation

Thermography has been shown to be a practical aid in the clinical evaluation of lameness. This modality specifically increases the accuracy of diagnosis. Thermography represents skin temperature, usually pictorially. The techniques involve contacting and noncontacting modalities. Noncontacting thermography, which detects infrared radiation, is the most accurate. In order to be accurate, thermography must be performed in a temperature-controlled, draft-free area. The area should be protected from sunlight to avoid erroneous heating of the skin, and the hair length should be uniform. Thermography detects heat before it is perceptible during routine physical examination; therefore, it is useful for early detection of laminitis, stress fractures, and tendinitis. It offers a noninvasive means of evaluating the blood supply to an injured part and offers one of the only reliable means to evaluate blood flow to the foot of horses with navicular syndrome. Thermography also is useful for the early identification of stress injuries to the contralateral limb of convalescing orthopedic patients. Thermography is an excellent adjunct to clinical and radiographic examination. It is complementary to other imaging techniques such as ultrasonography and scintigraphy.

Ethmoidal hematoma in nine horses

Ethmoidal hematoma was diagnosed in 9 horses by results of physical examination, endoscopy, radiography, and histologic examination of tissues. The horses had stertorous breathing (n = 4) or intermittently sanguineous nasal discharge (n = 7). All horses underwent sinusotomy and extirpation of the lesion. At reexamination 15 to 104 months after surgery (mean, 61 months), 3 horses had recurrence of ethmoidal hematoma, and 1 horse had ethmoidal hematoma involving the contralateral ethmoturbinates. One of the horses with recurrence of ethmoidal hematoma also developed a contralateral lesion; both lesions recurred and additional surgeries were performed.

Strength characteristics and failure modes of suture patterns in severed goat tendons

The load-to-gap formation, maximum load, gap present at maximum load, and failure mode were compared among four suture patterns: Bunnell-Mayer, modified Kessler, Mason-Allen, and simple interrupted. Sixty-four goat tendons were sutured with 2-0 monofilament polypropylene in one of the patterns and distracted at 92 cm/min with an electrohydraulic materials testing system. All tests were filmed at 40 frames/sec with an intermittent pin registered camera. The load-to-gap formation was not significantly different among the Bunnell (13.3 +/- 1.5 newtons [N]), Kessler (12.8 +/- 1.3 N), and simple interrupted (11.7 +/- 1.7 N) patterns. The Mason-Allen pattern was significantly different )8.2 +/- 0.5 N). The Bunnell-Mayer had the highest mean maximum load to failure (43.0 +/- 1.6 N) followed by the modified Kessler (34.1 +/- 1.9 N). There was no difference between the Mason-Allen (22.9 +/- 1.4 N) and simple interrupted (21.2 +/- 1.4 N). All of the patterns permitted at least a 1 cm gap to form when the maximum load was applied. The Bunnell pattern caused severe constriction of the tendon and failed by suture material disruption. The modified Kessler caused some focal constriction, but the suture material pulled out before breaking and sliced the tendon in the process. The Mason-Allen and the simple interrupted patterns sliced the tendon as the suture pulled out of the tendon.

Injuries to the cranial cruciate ligament and associated structures: summary of clinical, radiographic, arthroscopic and pathological findings from 10 horses

The clinical, radiographic, arthroscopic and pathological findings of 10 horses with injury to the cranial cruciate ligament are presented. The most consistent clinical signs included moderate to severe distension of the femoropatellar joint and a Grade III to a Grade V out of V lameness. Craniocaudal instability could be elicited in five horses under general anaesthesia and in one conscious horse. Radiographic evaluation of the stifles revealed that avulsion fracture of the medial intercondylar eminence was the most common finding in six out of 10 horses. Arthroscopic examination of the affected femorotibial joints were performed in five horses. This confirmed the presumptive diagnosis of cranial cruciate ligament injury or rupture. Post mortem examinations were performed on two horses which documented partial tears of the cranial cruciate ligament.

Diagnosis and treatment of the navicular syndrome in horses

Navicular syndrome can be treated in a variety of ways. This is related to the fact that it has a variety of causes. Prognostically, most horses will improve with treatment. One can expect about 50 per cent of the horses to become useably sound for 1 year, no matter what treatment is used. The disease is progressive, and affected horses eventually will need to be retired because of lameness. The author's therapeutic approach is to utilize shoeing as the primary therapy. Shoeing is performed to correct structural problems and to ensure that shoeing is physiologically sound. Nonsteroidal anti-inflammatory drugs are not used unless radical changes have been made in the shoeing. In cases of confirmed distal interphalangeal joint synovitis, either sodium hyaluronate or polysulfated glycosaminoglycans will be used in conjunction with shoeing. In cases where decreased circulation is documented, isoxsuprine hydrochloride will be administered if shoeing alone has not improved the horse within 6 weeks. If therapy does not improve the horse within 6 to 12 weeks, palmar digital neurectomy is recommended.

Shoeing principles for the management of navicular disease in horses

Navicular disease was diagnosed in 36 horses. Each horse was treated, using shoeing as the only major means of treatment. Phenylbutazone was used initially for 10 days after shoeing. Shoeing was designed to correct preexisting problems, enhance physiologic function of the foot, and ease breakover of the foot. The horses were evaluated over a period ranging from 12 to 54 months. The lameness improved in all horses. Thirty-one of the 36 horses treated were not lame when last evaluated. Shoeing was most effective when performed within 8 months of the first signs of lameness. Also, horses used for show ring performance classes had a better response to treatment than did horses used for gaming or jumping.

Small intestine incarceration through the epiploic foramen of the horse

Fifteen horses were referred to Purdue University or to the University of Georgia because of colic. Each of these horses had small intestine incarcerated through the epiploic foramen. However, signs of pain, gastric reflux, and small intestine distention were not consistent signs, as would have been expected with small intestine strangulation/obstruction. In 10 of the 15 cases, abdominal fluid analysis provided the decisive information needed for surgical intervention. Surgery was performed in 14 cases. The small intestine was incarcerated through the epiploic foramen in a right-to-left direction in 12 cases and in a left-to-right direction in 3 cases. The intestinal incarceration was reduced by gentle traction on the adjacent unaffected intestine. Resection and anastomosis were performed in 10 cases. Twelve of the 14 surgical patients died, and it was believed that the failure to intervene surgically at an earlier time contributed to these poor results. Surgery was delayed in most cases because of the inconsistent clinical signs observed in these horses. It was concluded that small intestine incarceration through the epiploic foramen should be suspected in any case of colic that has inconsistent physical findings and does not resolve in short time. Further, serial abdominal fluid analysis should be used in such cases in order to detect changes or trends that would indicate a lesion requiring surgical intervention.

Thermographic evaluation of horses with podotrochlosis

The distal forelimbs of 10 clinically normal horses with hair clipped on 1 limb were thermographically scanned before and after exercise. The thermal patterns, temperature distribution, and temperature changes after exercise were determined and compared with those of 8 horses with podotrochlosis. Clipping the hair did not cause changes in the thermal patterns, but the clipped limbs were warmer than the unclipped limbs. The temperature of the limbs of horses with podotrochlosis did not increase as much after exercise as did the limbs of normal horses. The failure of skin temperature increase correlated with the radiographic evidence of enlarged vascular foramina in the navicular bone. Because the failure to increase skin temperature after exercise is the result of low blood flow, the enlarged vascular foramen can be related to a state of low blood flow.

Rectal prolapse in the horse

Eleven horses with rectal prolapses were examined at Purdue University. Nine of the 11 prolapses were corrected by submucosal resection. Four of those were treated by a modified submucosal resection that apposes mucosa as well as submucosa. Follow-up of 8 cases, at intervals ranging from 4 months to 6 years, established that rectal prolapse did not recur following the resection.

Blockade of biogenic amine synthesis: its effect on the responses to leptazol and dexamphetamine in rats

1. The convulsive effects of leptazol in the rat are potentiated by prior treatment with dexamphetamine.2. An intact dopamine synthesis is necessary for the potentiation of the convulsive action of leptazol.3. An intact noradrenaline synthesis is not necessary for this action of amphetamine, as long as the dopamine synthesis is intact.4. An intact 5-hydroxytryptamine synthesis is not necessary for the potentiation to be shown.5. Blockade of either noradrenaline, dopamine or 5-hydroxytryptamine synthesis has no direct effect on leptazol convulsions.6. It is possible that it is an intact 3-4 dihydroxyphenylalanine (dopa) synthesis rather than an intact dopamine synthesis that is involved.

Effect of pretreatment with monoamine oxidase inhibitors or (+)-amphetamine on leptazol convulsions in mice and rats

IT has been claimed that monoamine oxidase inhibitors inhibit the actions of leptazol in experimental animals (Chow & Hendley, 1959; Prockop, Shore & Brodie, 1959; Yen, Salvatore & others, 1962). But other workers have failed to confirm this anticonvulsant action (Kobinger, 1958; Lessin & Parkes, 1959) and some have claimed a proconvulsant effect (Sansome & Dell'Omodarme, 1963; Spoerlein & Ellman, 1961). Reports of the effect of (+)-amphetamine on leptazol convulsions are equally conflicting. Small doses capable of antagonizing electroshock convulsions are described as ineffective against leptazol according to Wolff & Stock (1966), whilst Friebel & Klatt (1959) demonstrated a proconvulsant action. Reserpine enhances the effect of leptazol in animals, the greatest effect appearing to coincide with maximal depletion of tissue amines. If the animals are pretreated with a monoamine oxidase inhibitor before receiving reserpine, however, the subsequent sensitivity of the animal to leptazol is reduced (Pfeifer & Galambos, 1967) or is unaffected (Chen & Bohner, 1961; Spoerlein & Ellman, 1961).

We report initial observations during a re-examination of the interaction between leptazol and five representative monoamine oxidase inhibitors.