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Topic:Surgery

Surgery for horses encompasses a range of procedures performed to diagnose, treat, or manage various medical conditions. These procedures may involve soft tissue or orthopedic interventions and require specialized techniques to accommodate the unique anatomical and physiological characteristics of equines. Common surgical procedures in horses include colic surgery, fracture repair, and arthroscopy. The success of equine surgery depends on numerous factors, including the type of procedure, the horse's overall health, and post-operative care. This page compiles peer-reviewed research studies and scholarly articles that explore surgical techniques, outcomes, and advancements in equine surgical practices.
Survey of arthroscopic surgery for carpal chip fractures in thoroughbred racehorses in Japan.
The Journal of veterinary medical science    April 20, 2001   Volume 63, Issue 3 329-331 doi: 10.1292/jvms.63.329
Shimozawa K, Ueno Y, Ushiya S, Kusunose R.Medical and racing records of 155 Thoroughbred racehorses that underwent arthroscopic surgery for carpal chip fractures were investigated. Articular damage for 98.4% of the fractures was classified as G1 or G2 using McIlwraith's criteria. The rate of return to racing after surgery was 82.6%. Evaluation of racing performance after surgery was attempted using a placing index (PI) based on race finish position. There was no significant difference in the PI distribution between horses that underwent surgery and other healthy horses.
Petrographic and geochemic evaluation of equine enteroliths.
American journal of veterinary research    March 30, 2001   Volume 62, Issue 3 350-358 doi: 10.2460/ajvr.2001.62.350
Hassel DM, Schiffman PS, Snyder JR.To characterize the texture, mineralogic features, and chemical features of enteroliths obtained from horses. Methods: Enteroliths from 13 horses with colic. Methods: Enteroliths were harvested from 13 horses that underwent ventral midline celiotomy for treatment of colic or necropsy because of colonic obstruction and rupture caused by enteroliths. Dietary and environmental history were determined via questionnaires or evaluation of medical records. In 7 horses that underwent surgical treatment for enterolithiasis, samples of colonic contents were obtained via an enterotomy in the pelvic flexu...
Comparison of detomidine and romifidine as premedicants before ketamine and halothane anesthesia in horses undergoing elective surgery.
American journal of veterinary research    March 30, 2001   Volume 62, Issue 3 359-363 doi: 10.2460/ajvr.2001.62.359
Taylor PM, Bennett RC, Brearley JC, Luna SP, Johnson CB.To compare detomidine hydrochloride and romifidine as premedicants in horses undergoing elective surgery. Methods: 100 client-owned horses. Methods: After administration of acepromazine (0.03 mg/kg, IV), 50 horses received detomidine hydrochloride (0.02 mg/kg of body weight, IV) and 50 received romifidine (0.1 mg/kg, IV) before induction and maintenance of anesthesia with ketamine hydrochloride (2 mg/kg) and halothane, respectively. Arterial blood pressure and blood gases, ECG, and heart and respiratory rates were recorded. Induction and recovery were timed and graded. Results: Mean (+/- SD) d...
External skeletal fixation in the management of equine mandibular fractures: 16 cases (1988-1998).
Equine veterinary journal    March 27, 2001   Volume 33, Issue 2 176-183 doi: 10.1111/j.2042-3306.2001.tb00597.x
Belsito KA, Fischer AT.Fifty-three cases of equine mandibular fractures were managed surgically from 1988-1998, of which 16 (30%) were repaired by external skeletal fixation (ESF). Three surgical methods were utilised: transmandibular 4.76 or 6.35 mm Steinmann pins incorporated into fibreglass casting material or nonsterile dental acrylic (methyl methacrylate - MMA) bars reinforced with steel; transmandibular 9.6 mm self-tapping threaded pins +/- 4.76 or 6.35 mm Steinmann pins incorporated into MMA bars reinforced with steel; and 4.5 mm or 5.5 mm ASIF cortical bone screws incorporated into MMA bars reinforced with s...
An in vitro biomechanical comparison of interlocking nail constructs and double plating for fixation of diaphyseal femur fractures in immature horses.
Veterinary surgery : VS    March 7, 2001   Volume 30, Issue 2 179-190 doi: 10.1053/jvet.2001.21396
Radcliffe RM, Lopez MJ, Turner TA, Watkins JP, Radcliffe CH, Markel MD.To compare the biomechanical properties of intact immature horse femurs and 3 stabilization methods in ostectomized femurs. Methods: 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 caudo...
Treatment of methicillin-resistant Staphylococcus epidermidis infection following repair of an ulnar fracture and humeroradial joint luxation in a horse.
Journal of the American Veterinary Medical Association    March 7, 2001   Volume 218, Issue 4 554-527 doi: 10.2460/javma.2001.218.554
Trostle SS, Peavey CL, King DS, Hartmann FA.A 27-month-old Rocky Mountain Horse was examined because of a fracture of the proximal portion of the ulna and luxation of the humeroradial joint (Monteggia fracture). Open reduction was performed, using a mechanical distractor, and the ulnar fracture was stabilized by application of a bone plate and screws. After surgery, the horse developed an infection of the surgical site, and bacterial culture of fluid from the surgical site yielded a pure growth of methicillin-resistant Staphylococcus epidermidis susceptible to oxytetracycline, erythromycin, rifampin, and vancomycin. Treatment with oxyte...
The effect of implanting gentamicin-impregnated polymethylmethacrylate beads in the tarsocrural joint of the horse.
Veterinary surgery : VS    March 7, 2001   Volume 30, Issue 2 126-131 doi: 10.1053/jvet.2001.21392
Farnsworth KD, White NA, Robertson J.To determine the effect of intra-articular gentamicin-impregnated polymethylmethacrylate (PMMA) beads inserted in the equine tarsocrural joint on the synovial fluid, synovial lining, and cartilage, and to determine the peak and sustainable gentamicin concentrations in synovial fluid and plasma. Methods: Pharmacokinetic, cytologic, and histologic study of the effect of gentamicin-impregnated PMMA on normal equine tarsocrural joints. Methods: Five healthy adult horses. Methods: Gentamicin-impregnated PMMA bead strands (3 strands each of 40 beads, with each strand containing 100 mg gentamicin) we...
Clinical experiences with axial deviation of the aryepiglottic folds in 52 racehorses.
Veterinary surgery : VS    March 7, 2001   Volume 30, Issue 2 151-160 doi: 10.1053/jvet.2001.21389
King DS, Tulleners E, Martin BB, Parente EJ, Boston R.To describe the clinical findings in 52 racehorses with axial deviation of the aryepiglottic folds (ADAF) and to report outcome in 33 of these horses after either rest or transendoscopic laser excision of aryepiglottic fold tissue. Methods: Retrospective study. Methods: Racehorses admitted for high-speed treadmill (HST) evaluation of poor performance. Methods: Medical records and videotapes of resting and exercising videoendoscopic examinations were reviewed. Racing performance records and owner or trainer interviews, at least 1 year after HST examination, were used to compare results after ei...
Thoracoscopic-assisted diaphragmatic hernia repair using a thoracic rib resection.
Veterinary surgery : VS    March 7, 2001   Volume 30, Issue 2 175-178 doi: 10.1053/jvet.2001.21395
Malone ED, Farnsworth K, Lennox T, Tomlinson J, Sage AM.To describe the surgical treatment of a dorsal diaphragmatic hernia in an adult horse using thoracic rib resection aided by thoracoscopy and a flank incision. Methods: Case report. Methods: One client-owned horse. Results: A six-year-old Dutch warmblood gelding was admitted for colic-associated colonic incarceration in a diaphragmatic hernia. Seven weeks after the initial colic surgery, the gelding underwent surgery to repair the defect. Thoracoscopy and a flank incision were used to identify the location of the hernia and the subsequent site of rib resection. The stomach was adhered to the ed...
Surgical arthrodesis of distal tarsal joints in 17 horses clinically affected with osteoarthritis.
Australian veterinary journal    February 28, 2001   Volume 79, Issue 1 26-29 doi: 10.1111/j.1751-0813.2001.tb10634.x
Adkins AR, Yovich JV, Steel CM.To evaluate the outcome of 17 horses that underwent surgical arthrodesis of the tarsometatarsal and distal intertarsal joints for treatment of lameness due to osteoarthritis. Methods: Retrospective clinical study using client-owned animals. Methods: Horses with hindlimb lameness were diagnosed with osteoarthritis of the distal tarsal joints following relief of lameness after intra-articular anaesthesia or intra-articular corticosteroid injection. Surgery to stimulate ankylosis was performed on 27 hocks by placing 3 diverging 3.2 mm drill holes approximately 3 cm through the tarsometatarsal and...
Caecal impactions managed surgically by typhlotomy in 10 cases (1988-1998).
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 74-76 doi: 10.1111/j.2042-3306.2000.tb05338.x
Roberts CT, Slone DE.Surgical management of caecal impactions has included several different procedures suggested over the years. Complete bypass of the caecum through an ileocolic or jejunocolic anastomosis has become common practice for first time caecal impaction management, especially when dysfunction is suspected. In our practice, however, caecal impactions have been managed surgically by typhlotomy alone and of the 10 cases (July 1988-June 1998), 9 underwent surgery for first time caecal impactions, received a typhlotomy, and had survived an average of 43 months at time of case review. At the time of surgery...
Muscle thickness and neuron density in the caecum of horses with chronic recurrent caecal impaction.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 69-73 doi: 10.1111/j.2042-3306.2000.tb05337.x
Schusser GF, Scheidemann W, Huskamp B.In this study, the hypothesis that caecal smooth muscle layers would be thinner and the linear neuron density of myenteric plexus greater was tested in normal horses compared to those with chronic recurrent caecal impaction. Four normal horses and 18 horses with chronic recurrent caecal impaction were subjected to euthanasia and 7 tissue samples were collected from each horse at different regions of the caecum (apex, dorsal body, cranial base, dorsal base, caudal base, caudal body, ventral body). Twelve horses with chronic recurrent caecal impaction were treated surgically. Only one tissue sam...
Risk factors for reduced postoperative fecal output in horses: 37 cases (1997-1998).
Journal of the American Veterinary Medical Association    February 24, 2001   Volume 218, Issue 3 414-420 doi: 10.2460/javma.2001.218.414
Little D, Redding WR, Blikslager AT.To determine prevalence and risk factors for development of ileus of the large intestine after surgery in horses, identified by reduced postoperative fecal output (RPFO). Methods: Retrospective study. Methods: 37 horses that developed RPFO after undergoing general anesthesia for reasons unrelated to the gastrointestinal tract. Methods: Fecal output was obtained from medical records as number of defecations per 24-hour period after surgery; RPFO was defined as < or = 3 defecations per 24-hour period after surgery. The reference population included 48 horses that defecated > or = 4 times during ...
Equine basal cell tumors: 6 cases (1985-1999).
Journal of veterinary internal medicine    February 24, 2001   Volume 15, Issue 1 43-46 doi: 10.1892/0891-6640(2001)0152.3.co;2
Slovis NM, McEntee MC, Fairley RA, Galuppo LD, Théon AP.Basal cell tumors are rare benign tumors in horses. Over a 15-year period, 6 horses were diagnosed with basal cell tumors. The tumors were well-circumscribed. freely moveable, firm, raised papules, nodules, or masses that ranged from 0.6 to 5 cm in diameter. Five of the 6 tumors were ulcerated. Based on gross appearance, the tumors were diagnosed as sarcoids, and 1 was diagnosed as a melanoma. The range of age of affected horses was 6-26 years. The tumors were identified clinically 1 week to 3 years before excision. In 4 horses for which information was available, complete surgical excision wa...
Fistulation of the auditory tube diverticulum (guttural pouch) with a neodymium:yttrium-aluminum-garnet laser for treatment of chronic empyema in two horses.
Journal of the American Veterinary Medical Association    February 24, 2001   Volume 218, Issue 3 405-361 doi: 10.2460/javma.2001.218.405
Hawkins JF, Frank N, Sojka JE, Levy M.Two horses with chronic empyema of the auditory tube diverticulum (guttural pouch) were refractory to medical treatment; empyema was bilateral in 1 horse and unilateral in the other. Both horses were treated by fistulation of the cartilage of the pharyngeal orifice by use of a neodymium:yttrium-aluminum-garnet laser in a noncontact manner. To maintain patency of the fistulae, indwelling catheters were placed into the openings created by the laser. For both horses, long-term follow-up did not reveal complications, and both owners were satisfied with results of the procedure. The authors recomme...
Evaluation of uniformity of morphological injury of the large colon following severe colonic torsion.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 98-100 doi: 10.1111/j.2042-3306.2000.tb05343.x
van Hoogmoed L, Snyder JR, Pascoe JR, Olander HJ.This report describes the evaluation of uniformity of morphological injury of the large colon following severe colonic torsion in 17 horses presented to the Veterinary Medical Teaching Hospital. In 16 horses, twist occurred at the colonic base and in 1 at the sternal and diaphragmatic flexure. Eleven of the 17 horses were subjected to euthanasia at surgery and 6 of 17 following surgical correction within 4 days postoperatively. The objective of this study was to determine if the degree of histological changes present at the pelvic flexure were uniformly distributed throughout the regions of th...
Celiotomy closure via permanent implantation of polyamide in horses.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 101-103 doi: 10.1111/j.2042-3306.2000.tb05344.x
Beroza GA, Perry RW, Cotter DM.Permanent implantation of nonabsorbable materials is appropriate in many surgical circumstances but is not commonly used to close equine celiotomies. This paper describes a simple method of continuous nonabsorbable implantation of polyamide suture used successfully to close 48 equine celiotomies. Forty-eight clean or clean-contaminated celiotomies were successfully performed over 5 years using this technique. The postsurgical survival observation period ranged from 1-6 years (median 3.5 years). There were 45 long-term survivors (93.75%). Only 2 minor implant complications (4.4%) were observed ...
Standing laparoscopic herniorrhaphy in stallions using cylindrical polypropylene mesh prosthesis.
Equine veterinary journal    February 24, 2001   Volume 33, Issue 1 91-96 doi: 10.2746/042516401776767476
Mariën T.Standing laparoscopic herniorrhaphy was performed in 9 stallions. Appropriate analgesia was achieved by sedation with detomidine and local flank infiltration with mepivacaine. Three portal sites at the paralumbar fossa were used to perform the herniorrhaphy by means of triangulation. A cylindrical polypropylene mesh was inserted and fixated in the inguinal canal. Subsequent adhesion formation resulted in an obliterated inguinal canal within 2 weeks. This minimal invasive technique allowed us to perform a testis sparing herniorrhaphy in the standing horse.
Comparison of radiography and scintigraphy in the diagnosis of dental disorders in the horse.
Equine veterinary journal    February 24, 2001   Volume 33, Issue 1 49-58 doi: 10.2746/042516401776767458
Weller R, Livesey L, Maierl J, Nuss K, Bowen IM, Cauvin ER, Weaver M, Schumacher J, May SA.Scintigraphy, with 99mTechnetium methylenediphosphonate (99mTc-MDP) and 99mTc-labelled leucocytes, was compared to radiography in the diagnosis of dental disease in the horse in a prospective case-controlled study, comprising 30 horses with clinical signs of dental disease and 30 control horses. In each case, right and left lateral, ventral and dorsal soft tissue and bone phase scintigraphic images were obtained after i.v. injection of 1 GBq/100 kg bwt 99mTc-MDP, using a gamma camera. The same views were acquired in 10 horses with clinical signs of dental disease and 12 control horses after in...
Diagnosis and treatment of chronic recurrent caecal impaction.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 65-68 doi: 10.1111/j.2042-3306.2000.tb05336.x
Huskamp B, Scheidemann W.Ninety-six horses with chronic recurrent caecal impaction associated with hypertrophy of muscle layers in the caecal base or in the whole caecum were examined from 1990 to 1996. Enlargement of the caecocolic orifice was completed surgically in 58 horses. Of those horses having surgery, 50 were discharged from the hospital while 8 were subjected to euthanasia at the hospital due to complications. Twenty-seven of the 50 horses discharged were normal at follow-up while 23 died or were subjected to euthanasia due to acute or recurrent colic, recurrent impaction in the ascending or descending colon...
Design and clinical use of a modified colon tray for large colon evacuation in the horse.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 81-85 doi: 10.1111/j.2042-3306.2000.tb05340.x
Mariën T, Adriaenssen A, Segers L.A modified colon tray to perform large colon evacuations in horses was designed. A funnel-shaped accessory was constructed to create a mechanical separation between the sterile and nonsterile part of the tray. Sterile hooks were used to make a temporary and stabile colostomy. Thirty horses with surgical correction of nonstrangulating large colon obstruction underwent a large colon evacuation with this modified tray. The surgical procedure was uncomplicated and resulted in a positive outcome in 29 horses. This less labour-intensive way to evacuate the large colon results in minor contamination ...
Subchondral cystic lesions of the proximal extremity of the tibia in horses: 12 cases (1983-2000).
Journal of the American Veterinary Medical Association    February 24, 2001   Volume 218, Issue 3 408-413 doi: 10.2460/javma.2001.218.408
Textor JA, Nixon AJ, Lumsden J, Ducharme NG.To determine clinical and radiographic features of subchondral cystic lesions (SCL) of the proximal extremity of the tibia in horses that could be used to classify these lesions as being related to osteochondrosis or osteoarthritis and to evaluate results of surgical debridement. Methods: Retrospective study. Methods: 12 horses with 14 SCL. Methods: Medical records and radiographs obtained before and after treatment were reviewed. Results: In 6 young horses (8 lesions), SCL were considered to be related to osteochondrosis; all involved the lateral tibial condyle. The remaining 6 horses were ma...
Transendoscopic laser treatment of rostral displacement of the palatopharyngeal arch in four horses.
Journal of clinical laser medicine & surgery    February 24, 2001   Volume 17, Issue 2 49-52 doi: 10.1089/clm.1999.17.49
Blikslager AT, Tate LP, Tudor R.To document the use and clinical outcome of transendoscopic laser techniques for treatment of rostral displacement of the palatopharyngeal arch (RDPA) in horses. Background: Rostral displacement of the palatopharyngeal arch is a rare cause of upper respiratory noise and exercise intolerance in horses, and may be associated with abnormal laryngeal anatomy. There are few reports of successful treatment of this condition, and no reports of the treatment of RDPA using laser techniques. Methods: The diagnosis of RDPA was based on the presence of palatal tissue covering the dorsal aspect of the aryt...
Effect of a leukocyte-depleting filter in an extracorporeal circuit used for low-flow ischemia and reperfusion of equine jejunum.
American journal of veterinary research    February 24, 2001   Volume 62, Issue 1 87-96 doi: 10.2460/ajvr.2001.62.87
Van Hoogmoed LM, Snyder JR, Nieto JG, Harmon FA, Timmerman BL.To determine effect of leukocyte depletion on hematologic, morphologic, and metabolic variables of equine jejunum after induction of arterial low-flow ischemia and reperfusion by use of an extracorporeal circuit. Methods: 14 healthy adult horses. Methods: A segment of jejunum was surgically removed and maintained in an isolated circuit for 3 hours (control group), arterial flow was reduced to 20% of baseline for 40 minutes followed by 1 hour of reperfusion (low-flow group), or leukocyte depletion was filter-induced, and low-flow ischemia and reperfusion were conducted as in the low-flow contro...
Short- and long-term survival and prevalence of postoperative ileus after small intestinal surgery in the horse.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 42-51 doi: 10.1111/j.2042-3306.2000.tb05333.x
Freeman DE, Hammock P, Baker GJ, Goetz T, Foreman JH, Schaeffer DJ, Richter RA, Inoue O, Magid JH.The records of 74 horses that recovered from anaesthesia after surgery for a small intestinal lesion from 1994 to 1999 were reviewed. Sixty-three horses (85%) had a strangulating lesion and 43 of these (68%) had a resection and anastomosis. Four of 11 horses (36%) without a strangulating lesion had a resection and anastomosis. Sixty-three horses (85%) survived to discharge, with a survival rate of 53/63 in horses with a strangulating lesion (84%) and 10/11 (91%) in others. For all lesions, short-term survival for all end-to-end anastomoses (91%; 21/23) and for no resection (92%; 23/25) were su...
Effects of intraluminal distention and decompression on microvascular permeability and hemodynamics of the equine jejunum.
American journal of veterinary research    February 24, 2001   Volume 62, Issue 2 225-236 doi: 10.2460/ajvr.2001.62.225
Dabareiner RM, White NA, Donaldson LL.To determine whether intraluminal distention and subsequent decompression of the equine jejunum affects intestinal blood flow, hemodynamics, and microvascular permeability. Methods: 5 healthy adu t horses. Methods: Horses were anesthestized and underwent exploratory laparotomy. Two jejunal segments were identified as sham-operated or instrumented segments. After baseline values were obtained, intraluminal distention was created in the experimental segment to induce an ntraluminal pressure of 18 cm H2O. After 120 minutes of distention, the intestine was decompressed for 120 minutes. Mesenteric ...
Effect of extensive ileal resection with a large resulting mesenteric defect and stapled ileal stump in horses with a jejunocaecostomy: a comparison with other anastomotic techniques.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 52-58 doi: 10.1111/j.2042-3306.2000.tb05334.x
Bladon BM, Hillyer MH.Extensive resection of the ileum of the horse, using automated stapling equipment followed by a stapled jejunocaecostomy, without closure of the mesenteric defect, was evaluated prospectively as a surgical treatment for lesions involving the distal small intestine. Of 153 horses treated surgically for colic, 10 horses with strangulating lesions involving the distal ileum were treated by extensive resection and jejunocaecal anastomosis leaving a residual mesenteric defect. These were compared with 12 horses with jejunoileal lesions treated by jejunocaecal anastomosis with closure of the mesente...
Nephrosplenic entrapment in the horse: a retrospective study of 174 cases.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 95-97 doi: 10.1111/j.2042-3306.2000.tb05342.x
Hardy J, Minton M, Robertson JT, Beard WL, Beard LA.The clinical findings and outcome of 161 horses diagnosed with 174 episodes of nephrosplenic entrapment (NSE) were reviewed retrospectively. The median age at presentation was 5 years (9 months to 24 years), and duration of colic was 2-92 h. Nasogastric reflux was present in 49 of 113 horses (43.4%) and was significant (> or = 21) in 32 (28.3%) horses. The recurrence rate was 13/161 (8.1%). Thirteen horses (13/174, 7.5%) had other lesions including small intestinal obstruction (4), 360 degrees large colon torsion (5), gastric rupture (2), thromboembolic colic (1) and small colon infarction (1)...
Colic surgery in 206 juvenile thoroughbreds: survival and racing results.
Equine veterinary journal. Supplement    February 24, 2001   Issue 32 32-36 doi: 10.1111/j.2042-3306.2000.tb05331.x
Santschi EM, Slone DE, Embertson RM, Clayton MK, Markel MD.The purpose of our study was to determine the types of lesions that cause colic in juvenile Thoroughbreds, factors associated with these lesions and the subsequent survival and athletic performance of the juveniles. The age of juvenile Thoroughbreds requiring surgical exploration for abdominal pain has an influence on the type of lesion causing colic. The short-term survival rate (discharge from the hospital) after colic surgery for foals was 85% and was strongly influenced by the lesion causing colic. Thirteen percent of juveniles recovered from the first surgery experienced another severe co...
Prevalence and prognostic importance of hypomagnesemia and hypocalcemia in horses that have colic surgery.
American journal of veterinary research    February 24, 2001   Volume 62, Issue 1 7-12 doi: 10.2460/ajvr.2001.62.7
Garcia-Lopez JM, Provost PJ, Rush JE, Zicker SC, Burmaster H, Freeman LM.To determine the prevalence of hypomagnesemia and hypocalcemia in horses with surgical colic. Methods: 35 horses with surgically managed colic. Methods: Serum concentrations of total magnesium (tMg2+) and calcium (tCa2+), as well as ionized magnesium (iMg2+) and calcium (iCa2+) were analyzed before surgery and 1, 3, 5, and 7 days following surgery. A lead-II ECG and pertinent clinical data were also obtained at each time. Results: Preoperative serum tMg2+ and iMg2+ concentrations were below the reference range in 6 (17%) and 19 (54%) horses, respectively. Serum concentrations of tCa2+ and iCa2...