Objective—To compare heat generation during insertion, pullout strength, and associated microdamage between a self-tapping positive profile transfixation pin (STTP) and nontapping positive profile transfixation pin (NTTP).
Sample Population—30 pairs of third metacarpal bones (MC3s) from adult equine cadavers.
Procedures—One MC3 of each pair was assigned to the STTP group; the other was assigned to the NTTP group. The assigned pin was inserted into the diaphysis in a lateral to medial direction. Bone temperature increase during pilot-hole drilling and pin insertion was recorded at 1 mm from the final thread position with wire thermocouples at cis and trans cortices. Resistance to axial extraction before and after cyclic loading was measured in a material testing device, and microstructural damage caused by transfixation pin insertion was assessed with scanning electron microscopy.
Results—The STTP group developed a significant increase in bone temperature, compared with the NTTP group. No significant difference was found between the mean maximal pullout strength of the STTP and the NTTP in both non–cyclic-loaded and cyclic-loaded groups. Microdamage to the bone-pin interface was lower when the STTP versus the NTTP was used, but more bone debris was apparent after inserting the STTP.
Conclusion and Clinical Relevance—Because of the significant increase in temperature generation and debris accumulation despite similar pullout strengths and lesser microfracture formation, the STTP likely poses a higher risk of bone necrosis and potential loosening than the NTTP. This might be corrected by redesign of the tapping aspect of the STTP.
Case Description—4 horses with a history of neck pain, abnormal head carriage, and related inability to perform were examined. Cranial nuchal bursitis was diagnosed in 2 horses, and caudal nuchal bursitis was diagnosed in the other 2.
Clinical Findings—All 4 horses had prominent swelling in the region between the frontal bone and temporal fossa (ie, the poll) and abnormal head carriage. Ultrasonographic examination revealed fluid distention and synovial thickening of the cranial or caudal nuchal bursa in all 4 horses. Ultrasonography-guided aspiration of the affected region was performed successfully in 3 horses. Radiography revealed bony remodeling and mineralization over the dorsal aspect of the atlas in 1 horse and a radiolucency at the axis in another. Nuclear scintigraphy revealed an increase in radioisotope uptake at the level of C2 in 1 horse. Although a septic process was considered among the differential diagnoses in all horses, a septic process could only be confirmed in 1 horse.
Treatment and Outcome—All horses were refractory to conservative management consisting of intrabursal injection of anti-inflammatory medications. Bursoscopic debridement and lavage of the affected bursae resulted in resolution of the clinical signs in all horses, and they all returned to their intended use.
Clinical Relevance—Cranial and caudal nuchal bursitis, of nonseptic or septic origin, should be considered as a differential diagnosis in horses with head and neck pain. Horses undergoing surgical intervention consisting of nuchal bursoscopy have the opportunity to return to their original degree of exercise. (J Am Vet Med Assoc 2010;237:823–829)
Objective—To determine prevalence, clinical findings, and long-term survival rate after surgery associated with incarceration of the small intestine through the gastrosplenic ligament (ISIGL) in horses.
Design—Retrospective case series.
Animals—14 horses with ISIGL.
Procedures—Medical records of horses with ISIGL examined between January 1994 and December 2006 were reviewed. Signalment, initial physical examination findings, results of abdominal fluid analysis, and clinical laboratory values were recorded, along with surgical findings, including segment of incarcerated intestine and surgical procedures performed. Long-term survival data were obtained through client interviews.
Results—Clinical findings included small intestinal distention identified via rectal palpation (10/14 horses) or transabdominal ultrasonography (8/11), nasogastric reflux (4/14), and abnormal abdominal fluid (9/9). All horses required intestinal resection and anastomosis. Postoperative complications included adynamic ileus (5/14 horses), incisional infection (4/14), diarrhea (3/14), and laminitis (1/14). No breed or age predilection was detected, although geldings were at increased risk for ISIGL. Long-term survival rate was 79% (11/14 horses).
Conclusions and Clinical Relevance—ISIGL was an uncommon cause of colicin this hospital population. With appropriate surgical intervention and postoperative management, the long-term prognosis for surgically treated horses was fair to good.
Objective—To determine the prevalence of hypomagnesemia
and hypocalcemia in horses with surgical
Animals—35 horses with surgically managed colic.
Procedure—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+ were less than the reference
range in 20 (57%) and 30 (86%) horses before
surgery. Horses with strangulating lesions of the gastrointestinal
tract had significantly lower preoperative
serum concentrations of iMg2+ and iCa2+, as well as a
higher heart rate than horses with nonstrangulating
lesions. Horses that developed postoperative ileus
had significantly lower serum concentrations of iMg2+
after surgery. Serum concentrations of magnesium
and calcium (total and ionized) correlated significantly
with the PR, QRS, QT, and corrected QT (QTc) intervals.
Horses that were euthanatized at the time of
surgery (n = 7) had significantly lower preoperative
serum concentrations of iMg2+, compared with horses
that survived. Neither serum magnesium nor calcium
concentrations were predictors of hospitalization
time or survival.
Conclusions and Clinical Relevance—Hypomagnesemia
and hypocalcemia were common during
the perioperative period, particularly in horses with
strangulating intestinal lesions and ileus. Serum concentrations
of tMg2+ and tCa2+ were less sensitive
than iMg2+ and iCa2+ in detecting horses with hypomagnesemia
and hypocalcemia. ( Am J Vet Res
Objective—To determine the tissue distribution of enrofloxacin after intramammary or simulated systemic administration in isolated perfused sheep udders by measuring its concentration at various sample collection sites.
Sample—26 udders (obtained following euthanasia) from 26 healthy lactating sheep.
Procedures—For each isolated udder, 1 mammary gland was perfused with warmed, gassed Tyrode solution. Enrofloxacin (1 g of enrofloxacin/5 g of ointment) was administered into the perfused gland via the intramammary route or systemically via the perfusion fluid (equivalent to a dose of 5 mg/kg). Samples of the perfusate were obtained every 30 minutes for 180 minutes; glandular tissue samples were obtained at 2, 4, 6, and 8 cm from the teat base after 180 minutes. The enrofloxacin content of the perfusate and tissue samples was analyzed via high-performance liquid chromatography with UV detection.
Results—After intramammary administration, maximun perfusate enrofloxacin concentration was detected at 180 minutes and, at this time, mean tissue enrofloxacin concentration was detected and mean tissue enrofloxacin concentration was 123.80, 54.48, 36.72, and 26.42 μg/g of tissue at 2, 4, 6, and 8 cm from the teat base, respectively. Following systemic administration, perfusate enrofloxacin concentration decreased with time and, at 180 minutes, tissue enrofloxacin concentrations ranged from 40.38 to 35.58 μg/g of tissue.
Conclusions and Clinical Relevance—By 180 minutes after administration via the intramammary or systemic route in isolated perfused sheep mammary glands, mean tissue concentration of enrofloxacin was greater than the minimum inhibitory concentration required to inhibit growth of 90% of many common mastitis pathogens in sheep. Use of either route of administration (or in combination) appears suitable for the treatment of acute mastitis in sheep.