Castration in the standing horse combining laparoscopic and conventional techniques.

BACKGROUND: Standing laparoscopic castration without orchidectomy has been shown to be a reliable method of castration in animals with abdominal cryptorchidism, but it cannot be recommended as a method of castration in those with inguinal cryptorchidism or normal males. An alternative laparoscopic method for the castration of horses with descended testes was developed. OBJECTIVES: To report the results of laparoscopy-assisted abdominal transection of the spermatic cord and a modified open method in the standing horse for castration of descended testes in unilateral abdominal cryptorchids. STUDY DESIGN: Descriptive case series. METHODS: Fifteen unilateral abdominal cryptorchids were castrated laparoscopically by performing intra-abdominal ligation of both spermatic cords. The spermatic cord of the cryptorchid testis was not transected. After intra-abdominal transection of the spermatic cord of the descended testis, the testis was removed by an open castration technique in the standing horse. Data collected included time taken to perform the surgical procedure, surgical complications and post-operative recovery. RESULTS: Abdominal testes were located on the right side in eight horses and on the left in seven. The surgical procedure was easy to perform and few intra- or post-operative complications were seen. Pulse and respiration rates and rectal temperatures remained within normal limits during the evaluation period in all but one animal, which displayed transient pyrexia. The scrotal and laparoscopic incisional wounds healed well without any signs of swelling or exudate. In one Warmblood, there was prolapse of subcutaneous tissue the day after surgery, which retracted in 3 days. The owners were contacted by telephone at 2-3 months after discharge. Post-operative recovery had been uneventful in all horses. MAIN LIMITATIONS: This study included a small number of cases in which all surgeries were performed by or under the supervision of the same surgeon. Follow-up was limited to telephone reports from owners. CONCLUSIONS: A laparoscopic technique that is combined with an open scrotal incision to remove the descended testis in the standing horse was developed and shown to be a safe and reliable option for the castration of unilateral abdominal cryptorchids.

How securely is the testicular artery occluded in the spermatic cord by using a ligature?

REASONS FOR PERFORMING STUDY: There are no studies on the ideal ligature technique for the spermatic cord. OBJECTIVES: To compare the maximal resistance pressure in the testicular artery and the maximal tensile forces to produce failure of 2 different ligature techniques used for ligation of the equine spermatic cord. METHODS: The capabilities of 2 types of ligatures, single knot loop and double knot loop, were assessed using a pressure-resistance test in testicular arteries and with an in vitro mechanical evaluation of the tensile strength by single cycle-to-failure testing. RESULTS: In the pressure-resistance test, the mean ± s.d. peak force at failure of the single knot loop was 354.4 ± 91.7 mmHg and for the double knot loop 303.2 ± 62.0 mmHg. There was no significant difference between the maximal load to failure of the single knot loop and double knot loop technique. The pressure needed for rupture was significantly higher (P = 0.001) than for leakage. The maximal tensile force at failure of the single knot loop was significantly higher than the double knot loop (P = 0.028). There was no significant difference in load elongation properties to failure between the single knot loop and double knot loop. CONCLUSIONS: Although no significant differences were obtained in the pressure-resistance test, the single knot loop sustained significantly greater load to failure than the double knot loop in single cycle-to-failure testing. Based on these findings, it would appear that the performance of the single knot loop should be superior to the double knot loop. POTENTIAL RELEVANCE: Both ligature techniques are able to withstand the normal physiological intravascular pressure. The single knot loop has the greater breaking strength of the 2 ligatures tested and is less time consuming to perform and may therefore have advantages during equine castration.

Surgical thrombectomy in horses with aortoiliac thrombosis: 17 cases.

REASONS FOR PERFORMING STUDY: Aortoiliac thrombosis (AIT) is a progressive vascular disease characterised by an exercise-induced hindlimb lameness. After developing a surgical technique, a follow-up study was required. OBJECTIVES: To assess the surgical results of a surgical thrombectomy in horses with AIT, a chronic arterial occlusive disease of the aorta and its caudal arteries. METHODS: Seventeen cases showed the typical signs of AIT and diagnosis was confirmed by Doppler-ultrasonography. Average age of the horses was 12 years. Seven stallions, 6 mares and 4 geldings were included. RESULTS: The thrombus was located in the left hindlimb (5 cases), the right hindlimb (9 cases) or in both hindlimbs (3 cases). Two cases were operated on both limbs with a few days between surgeries. Nine (53%) horses regained their athletic performance and 2 horses were able to work for at least 30 min without complaint, instead of the initial 5 min prior to surgery. During surgery one horse had to be subjected to euthanasia because the thrombus was too tightly attached to the arterial wall and could not be removed. Two horses were subjected to euthanasia post operatively due to severe myopathy and one due to a femoral fracture during recovery. Two reocclusions of the treated artery occurred 4 months after surgical intervention: one horse was reoperated and, due to the extent of the thrombus and quality of the arterial wall, the horse was subjected to euthanasia; the other horse was subjected to euthanasia without a second surgery. A severe complication was the appearance of AIT in the contralateral limb after surgery as result of occlusion caused by an embolus loosened by the procedure. Post anaesthetic myopathy was seen in 4 (24%) of the cases and could be so severe that euthanasia had to be considered. CONCLUSION AND POTENTIAL RELEVANCE: Surgical intervention by means of a thrombectomy in horses with AIT should be considered; 65% of the horses regained athletic activity and 53% of the operated horses in this study performed at their previous level. Adequate padding, correct positioning, prevention of intraoperative hypotension and keeping surgery time as short as possible, are important parameters to prevent post operative myopathy.

Clinical efficacy of local administration of ceftiofur in a Staphylococcus aureus infection in tissue cages in ponies.

Ceftiofur concentrations in an infected and uninfected environment were compared and the efficacy of locally administered ceftiofur was evaluated in an experimental infection with Staphylococcus aureus in tissue cages. Eight ponies had tissue cages (TCs) implanted s.c. on each side of the neck. Into one of the cages 150 mg of ceftiofur was administered and fluid samples were taken to determine ceftiofur concentrations. After 1 week the other TC was infected with S. aureus and subsequently treated with 150 mg ceftiofur administered locally into the TC once daily for 21 days. Samples of fluid were taken to determine ceftiofur concentrations and for bacterial counts. Ceftiofur concentrations did not differ significantly in the infected and uninfected environments after single dose of 150 mg of ceftiofur. Concentrations were considerably in excess of the minimum inhibitory concentration (MIC) of the S. aureus strain used. A marked decrease of viable bacteria in tissue cage fluid (TCF) occurred. In five of seven ponies; however, the infection was not eliminated and abscess formation occurred. Therefore, local application of ceftiofur alone is not advisable for infections with S. aureus in secluded sites in horses, but should be used only with adjunctive therapy.

The complex blood supply to the equine testis as a cause of failure in laparoscopic castration.

REASONS FOR PERFORMING STUDY: Intra-abdominal ligation/ transection of the spermatic cord may result in necrosis of the testis; castration of abdominal cryptorchids via laparoscopy has therefore become common. Notwithstanding some adaptations of the technique, a small percentage of operations fail, prompting research into the anatomical background and clinical relevance of the procedure. HYPOTHESIS: That an alternate blood supply may prevent complete necrosis of the testis after spermatic cord transection. OBJECTIVE: To establish the prevalence of the problem in normal and cryptorchid stallions. METHODS: In a preliminary study, the spermatic cords of 8 normal stallions were ligated and transected at different sites and in various manners. Five weeks later the testes were removed and the vitality of both the testes and epididymes was evaluated. In a prospective clinical trial, intra-abdominal spermatic cord transection was performed in 241 cryptorchid and normal stallions. In cases of surgical failure, the testes were removed and histology performed. RESULTS: Examination of the specimen removed from the 8 animals of the preliminary study revealed that all epididymes were completely or largely spared. All except one testis were completely necrotic. In the patients that underwent surgery all abdominally retained testes (n = 123) were necrotic, while 5 out of 88 inguinally retained and 8 out of 236 normally descended testes had partially survived. The pattern of survival differed between inguinally retained and normally descended testes. The epididymes of these 13 horses were (largely) vital. The (partial) survival of the epididymes and inguinally retained testes was ascribed to an alternate blood supply via anastomosing vessels derived from the cremasteric artery. A tributary from the external pudendal artery was considered responsible for the partial survival of normally descended testes. CONCLUSIONS AND POTENTIAL RELEVANCE: After intra-abdominal transection of the entire spermatic cord, 5.6% of inguinally retained and 3.4% of normally descended testes failed to become completely necrotic, as a result of an alternate blood supply via the cremasteric and/or external pudendal artery. Therefore, laparoscopic castration without orchidectomy cannot be recommended as a trustworthy method for castration of inguinal cryptorchids and normal stallions.

Accuracy of diagnostic arthroscopy for the assessment of cartilage damage in the equine metacarpophalangeal joint.

REASONS FOR PERFORMING STUDY: There are many noninvasive diagnostic methods used for evaluating chronic progressive joint disease, but each has severe limitations in the detection of early articular cartilage damage. OBJECTIVES: To evaluate the accuracy of arthroscopy as a diagnostic method for the assessment of the severity of cartilage surface damage on the proximal articular margin of the equine first phalanx (P1). HYPOTHESIS: That arthroscopic assessment of the visible cartilage provides 1) a good indication of the integrity of the cartilage surface and 2) a good estimation of the status of the cartilage surface of the entire articular area of P1. METHODS: Arthroscopic examination of the dorsal pouch of the metacarpophalangeal joint was performed in the left front limbs of 74 slaughter horses (age 5 months to 23 years). The appearance of the visible cartilage of P1 was scored by 2 independent arthroscopists, using the SFA arthroscopic grading system. The joints were dissected after completion of the arthroscopic procedure. The cartilage degeneration index (CDIP1) was determined and used as a quantitative measure for the overall degree of cartilage surface deterioration on the articular area of P1. Further, CDI values were determined for the dorsal articular margin of P1 (CDIdam), i.e. the area that can be visualised with arthroscopy. The CDIdam values were classified into 3 groups (CDIdam<25%, minor lesions; 25%45%, severe lesions). Differences between the 2 arthroscopists were evaluated statistically in a nonparametric test and Pearson correlation coefficients (r) with matching P values were determined for the correlations between SFA and CDIdam and between CDIP1 and CDIdam. The level of significance was set at P<0.05. RESULTS: Differences between SFA scores of the 2 arthroscopists were not significant (P = 0.22). In the group of joints with minor cartilage changes, there was no correlation between SFA and CDIdam (r = 0.12; P = 0.71), but there was a significant correlation between CDIP1 and CDIdam (r = 0.95; P<0.01). In the group with moderate cartilage damage, there was an increase in correlation between SFA and CDIdam (r = 0.27; P = 0.09) and a decrease in the correlation between CDIP1 and CDIdam (r = 0.48; P<0.01). In the group with severe cartilage changes, there was a significant correlation between SFA and CDIdam (r = 058; P<0.01), but no significant correlation between CDIP1 and CDIdam (r = 0.43; P = 0.06). CONCLUSIONS: Arthroscopic assessment of cartilage lesions on the proximal articular surface of P1 in joints with minor cartilage damage leads to an underestimation of the actual damage because proteoglycan depletion and light cartilage fibrillation cannot be detected arthroscopically. In cases with mild cartilage damage, the status of the cartilage surface of the visible area of P1 is a good representation of the status of the entire articular surface. In cases with severe cartilage lesions, there is an overestimation of real damage. In such joints, the arthroscopic scoring system provides reliable information, but the visible area is not representative of the entire articular surface. POTENTIAL RELEVANCE: From a practical viewpoint, it can be stated that the arthroscopic grading of visible lesions on the equine P1 gives the best impression of overall cartilage damage in joints with moderately severe cartilage lesions. It should be realised, however, that this is the result of an underestimation due to the shortcomings of the grading system, which is neutralised by an overestimation due to the fact that the severity of lesions on the visible area of P1 is not representative for the entire articular surface.

Hormonal, metabolic and physiological effects of laparoscopic surgery using a detomidine-buprenorphine combination in standing horses.

OBJECTIVE: To assess the hormonal, metabolic and physiological effects of laparascopic surgery performed under a sedative analgesic combination of detomidine and buprenorphine in standing horses. STUDY DESIGN: Prospective study. ANIMALS: Eight healthy adult Dutch Warmblood horses and five healthy adult ponies undergoing laparoscopy were studied. Five healthy adult horses not undergoing laparoscopy were used as a control group. METHODS: The sedative effect of an initial detomidine and buprenorphine injection was maintained using a continuous infusion of detomidine alone. The heart and respiratory rate, arterial blood pH and arterial oxygen and carbon dioxide tensions were monitored, while blood samples were taken for the measurement of glucose, lactate, cortisol, insulin and nonesterified fatty acids (NEFA). The same variables were monitored in a control group of horses which were sedated, but which did not undergo surgery. At the end of the sedation period the effects of detomidine were antagonized using atipamezole. RESULTS: The protocol provided suitable conditions for standing laparoscopy in horses. Laparoscopy induced obvious metabolic and endocrine responses which, with the exception of NEFA values, were not significantly different from changes found in the control group. While atipamezole did not produce detectable adverse effects, it is possible that anatagonism may not be essential. CONCLUSIONS: The technique described reliably produces adequate sedation and analgesia for laparoscopic procedures. The level of sedation/analgesia was controlled by decreasing or increasing the infusion rate. Antagonism of the effects of detomidine may not be necessary in all cases.

[Hematogenous (suspected-)septic inflammation of the synovial fossa in the adult horse: rare but deceptive (3 case reports)]. / De haematogene (verdacht-) septische ontsteking van synoviale holten bij het volwassen paard: zelzaam maar verraderlijk (drie casussen).

Septic inflammation of the synovial fossa in the horse is a severe disorder that can lead to permanent invalidity. The synovitis can occur as a result of a perforating trauma, or via the blood (haematogenous). The latter route is rare in the adult horse. Three cases of suspected haematogenous septic synovitis are described in adult horses (older than 1 year). In two horses, timely and adequate treatment resulted in recovery, but this was followed by fatal recurrence. In one of these horses a persistent primary infection was found as cause; the other horse was not available for autopsy. The third horse was euthanized without treatment because the primary process was difficult to treat. It can be concluded that, in horses with suspected haematogenous septic inflammation of the synovial fossa, attention should be paid to the primary process--it is not enough to treat the synovitis alone.

A study on the pathogenesis of equine sesamoiditis: the effects of experimental occlusion of the sesamoidean artery.

In this study the potential role of circulatory disturbances in the pathogenesis of sesamoiditis was investigated by studying the clinical and histological effects of experimental occlusion of the sesamoidean artery, which is the main nutrient artery of the proximal sesamoid bone (PSB). For this purpose, five adult Dutch Warmblood horses were used in which the sesamoidean artery was occluded with polyvinyl alcohol foam particles. Bone labelling was carried out with oxytetracycline and calcein. All animal were checked clinically three times a week and radiographically at days 14, 21, 28 and 35. At day 35 the animals were killed and the fetlock was dissected and macroscopically evaluated. The PSBs were isolated and radiographed and the soft tissues adjacent to the abaxial side of the PSBs were histologically examined [routine histology and for the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP)]. The PSBs were divided into bony slices which were radiographed and evaluated histologically (routine, SP, CGRP, fluorescence). All horses showed a slight lameness that gradually diminished. Radiographically enlarged vascular channels were seen in only one horse. Histological data showed that on average 60% (range 37-89%) of the total area had been deprived of vascularization. In two horses an increase in the extent of the arterial network from the basal side of the PSB was seen. Only in the horse with the greatest extent of occlusion were bone necrosis and a reactively increased uptake of fluorochromes adjacent to the occluded arteries found. Bone density did not change. The distribution of neuropeptides in the surrounding soft tissues was not affected by the occlusion. From this study, it can be concluded that a large part of the arterial supply to the PSB can be interrupted without provoking histological and/or radiographic changes that are consistent with clinical sesamoiditis. Therefore, it seems very improbable that circulatory disturbances are a primary aetiopathogenic factor in the disease.