Haebeom Lee

The Effects of Static and Dynamic Loading on Biodegradable Magnesium Pins In Vitro and In Vivo

Here we systematically assess the degradation of biodegradable magnesium pins (as-drawn pure Mg, as-cast Mg-Zn-Mn, and extruded Mg-Zn-Mn) in a bioreactor applying cyclical loading and simulated body fluid (SBF) perfusion. Cyclical mechanical loading and interstitial flow accelerated the overall corrosion rate, leading to loss of mechanical strength. When compared to the in vivo degradation (degradation rate, product formation, uniform or localized pitting, and stress distribution) of the same materials in mouse subcutaneous and dog tibia implant models, we demonstrate that the in vitro model facilitates the analysis of the complex degradation behavior of Mg-based alloys in vivo. This study progresses the development of a suitable in vitro model to examine the effects of mechanical stress and interstitial flow on biodegradable implant materials.

Feasibility of Stifle Medial Meniscal Release in Toy Breed Dogs with and without a Joint Distractor

OBJECTIVE To investigate the feasibility of medial meniscal release (MMR) during stifle arthroscopy in toy breed dogs with and without a joint distractor. STUDY DESIGN Experimental cadaveric study. SAMPLE POPULATION Stifles (n = 40) from 20 canine cadavers (1.8-5.1 kg). METHODS Paired stifles were randomly assigned to the joint distractor group and the control group (n = 20 each). All stifles underwent arthroscopic transection of the cranial cruciate ligament followed by a release of the caudomedial meniscotibial ligament. After the procedures, all stifles were disarticulated. The degree of released meniscus was recorded subjectively by 5% increments. A MMR success was defined as a complete transection. The areas of femoral and tibial articular cartilage damage were calculated using india ink staining and digital imaging. The results were compared between groups and odds ratios were calculated. RESULTS All stifle arthroscopies were successful. The success rate of MMR was significantly higher (P = .013) with a joint distractor than without a joint distractor. MMR was 7.4 times more likely to succeed with a joint distractor than without a joint distractor. The distal femoral articular cartilage was significantly more damaged (P = .011) in the stifles without a joint distractor than in the stifles with a distractor. No difference was found between the 2 groups for damage to the tibial cartilage (P = .058). CONCLUSION Stifle arthroscopic MMR is feasible in toy breed dogs. Using a joint distractor is recommended for arthroscopic treatment based on our results because it significantly reduced the rate of incomplete release as well as iatrogenic cartilage damage.

Evaluation of porcine xenograft in collateral ligament reconstruction in beagle dogs.

This study evaluated the effectiveness of irradiated porcine tendon xenografts for lateral collateral ligament (LCL) reconstruction. Twenty healthy adult beagle dogs underwent LCL reconstruction using irradiated porcine tendons treated with poly-gamma-glutamic acid. Serological and histological assessments were performed to evaluate host immunological response at 3 and 12 months after surgery. The healing and functional integrity of the LCL reconstructions were assessed by mechanical testing and gait analysis. Histological assessment of the porcine xenografts showed gradual host cellular infiltration and graft collagen remodeling during the healing process. Porcine xenografts showed angiogenesis and no signs of inflammatory reaction. Additionally, biomechanical and gait evaluations supported graft functional integration with no differences between normal and porcine xenograft reconstruction at 12 months after surgery. Irradiated porcine xenografts showed greater cellular responses and healing properties in short- and long-term evaluations. Irradiated porcine tendons appear to be useful as xenografts for the reconstruction of damaged ligaments.

Comparison of the effects of isoflurane versus propofol-remifentanil anesthesia on oxygen delivery during thoracoscopic lung lobectomy with one-lung ventilation in dogs

This study compared effects of isoflurane inhalation (ISO) and propofol-remifentanil combined total intravenous anesthesia (TIVA) on oxygenation during thoracoscopic lung lobectomy with 30-min one-lung ventilation (1LV). Thoracoscopic right middle lung lobectomy was performed in ten dogs divided into ISO and TIVA groups, and cardiopulmonary parameters were measured with blood gas analysis. Throughout the study, isoflurane was inhaled up to 1.5%, and the infusion rates of propofol and remifentanil were 0.2 to 0.4 mg/kg/min and 6 to 11 µg/kg/h, respectively. Cardiac index was not affected in the ISO group, but it increased during 1LV in the TIVA group. There were significant alterations in arterial oxygen pressure, arterial oxygen saturation, oxygen content, and shunt fraction associated with 1LV in each group. However, oxygen delivery did not decrease significantly due to open chest condition, 1LV, or surgical maneuver in either group, rather it increased during 1LV in the TIVA group. All parameters showed no significant difference between groups. Pulmonary vascular resistant index was unaffected in both groups, and there was no difference between groups except in re-ventilation phase. Accordingly, the effect of both anesthetic regimens on oxygenation was not different between groups and can be used with short-term 1LV for thoracoscopic lung lobectomy in dogs.

Treatment of a giant pulmonary emphysematous cyst with primary bronchoalveolar papillary carcinoma in a Shih Tzu dog

OBJECTIVE To report the surgical treatment of a pulmonary emphysematous cyst concurrent with primary pulmonary bronchoalveolar papillary carcinoma in a dog. STUDY DESIGN Clinical case report. ANIMALS 12-year-old 6.4 kg spayed female Shih Tzu dog. METHODS The dog presented for surgical treatment of pulmonary emphysema. Radiography revealed that more than half of the left caudal lung lobe was enlarged and hyperlucent and computed tomography (CT) confirmed the presence of an emphysematous space. Thoracoscopic lung lobectomy was attempted but was converted to an intercostal thoracotomy due to poor visualization and pleural adhesions. A left caudal total lung lobectomy was performed using a self-cutting endoscopic stapler. RESULTS The dog recovered uneventfully and a postoperative histopathologic diagnosis of pulmonary cystic bronchoalveolar papillary carcinoma was made. Re-evaluation using a CT scan with contrast study on postoperative days 27 and 177 revealed no evidence of residual, metastatic, or recurrent lesions. The dog has been doing well since surgery during the 11 month follow-up period. CONCLUSION This case report suggests a potential relationship between pulmonary emphysematous diseases and primary lung tumors in dogs.

Laparoscopic kidney biopsy in dogs: Comparison of cup forceps and core needle biopsy

OBJECTIVE To investigate the feasibility of laparoscopic kidney biopsy with cup biopsy forceps in dogs (CupBF), and to compare to the use of a core biopsy needle (CoreBN). STUDY DESIGN Experimental; randomized, controlled design. ANIMALS Eight healthy, adult Beagle dogs. METHODS Dogs were randomized to undergo laparoscopic biopsy of the right kidney using either 5 mm CupBF or a 16 gauge CoreBN. Intraoperative hemorrhage of the biopsy site was monitored. Biopsy quality was evaluated for tissue fragmentation and crushing, presence of renal cortex with or without medulla, and number of glomeruli. Postoperative packed cell volume, urinalysis, and ultrasonographic appearance of the biopsy site were evaluated. RESULTS Biopsy specimens were obtained by both techniques and reliable hemostasis was achieved with direct compression in all dogs. The histologic score for CupBF biopsies was not significantly different from CoreBN biopsies. One CoreBN biopsy contained both renal cortex and medullar, while all CupBF biopsies contained cortex only. The mean (SD) number of glomeruli was significantly higher in CupBF biopsies [60 (9.1)] than CoreBN biopsies [26 (4.3)]. There was no gross hematuria, perirenal hematoma, or hydronephrosis in any dog postoperative. CONCLUSION Laparoscopic kidney biopsy in dogs using 5 mm cup biopsy forceps is feasible with minimal risk and more glomeruli obtained compared to laparoscopic kidney biopsy using 16 gauge core biopsy needles.

OPHTHALMIC EXAMINATION IN COMMON KESTRELS (FALCO TINNUCULUS) FROM SOUTH KOREA

Abstract The purpose of this study was to establish reference ophthalmic findings in the common kestrel (Falco tinnunculus). Twenty healthy adult kestrels were included in this study. Ophthalmic examinations included slit lamp biomicroscopy, fundus exam, Schirmer tear test, conjunctival bacterial culture and isolation, corneal touch threshold, tonometry, and corneal diameter measurement. Mean tear production was 7.4 ± 3.27 mm/min, and mean intraocular pressure measured via applanation tonometry was 10.5 ± 3.15 mm Hg. In addition, the mean corneal touch threshold was 29.8 ± 20.1 mm, and the mean corneal diameter was 9.8 ± 1.1 mm. Of the 25 conjunctival swabs, 23 (92%) yielded bacterial growth. Most of these bacteria were gram positive (69.6%); the most predominant genus was Staphylococcus. This study presents reference values for ophthalmic examinations in common kestrels.

Arthroscopic detection of medial meniscal injury with the use of a joint distractor in small-breed dogs

The goal of the present study was to evaluate the diagnostic value of a joint distractor in arthroscopy in small-breed dogs. Sixty stifle joints, which were collected from thirty cadavers, were used in this study. To simulate different injuries, no medial meniscal tear, a full-thickness vertical longitudinal tear, a partial-thickness vertical longitudinal tear, full- and partial-thickness vertical longitudinal tears, or a peripheral detachment were created on the caudal horn of the medial meniscus of each stifle joint along with rupture of the cranial cruciate ligament. Each stifle joint then underwent arthroscopy with and without a joint distractor. The sensitivity (Sn), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and correct classification rate (CCR) for the diagnosis of each type of medial meniscus pathology were calculated. For arthroscopy with and without a joint distractor, the Sn was 85% and 60%, the Sp was 96% and 92%, the PPV was 85% and 65%, the NPV was 96% and 90%, and the CCR was 94% and 86%, respectively. Arthroscopy is an effective diagnostic method for the assessment of medial meniscal pathologies in small-breed dogs, especially when performed with the aid of a joint distractor.

Bilateral Patellar Groove Replacement (PGR) in a Dog with Iatrogenic Trochlear Groove Damage

A 2-year-old, 1.94 kg spayed female Toy Poodle was referred for revision surgery for patellar reluxation following surgery for bilateral medial patellar luxation (MPL). Intermittent non-weight-bearing lameness of the right hindlimb and weight-bearing lameness of the left hindlimb were evident on general inspection. A physical examination revealed that there was a bilateral grade 4 MPL. On radiographs, the medial and lateral trochlear ridge was bilaterally worn out. Patellar groove replacement (PGR) was performed in two stages to replace the bilateral femoral trochlea that had a severely worn out groove. Corrective femoral osteotomy with increasing anteversion angle, tibial tuberosity transposition, medial releasing, lateral imbrications and PGR were performed on the right hindlimb. Six months after surgery on the right hindlimb, a PGR prosthesis was positioned medially on the frontal plane and tibial tuberosity transposition and lateral imbrications were performed on the left hindlimb. Two weeks after surgery, reluxation of the patella occurred on the left hindlimb. The tibial tuberosity transposition was performed to realign the patella more laterally than the previous surgery, and a patellar sling was applied. Two years after the last surgery, the patient showed no pain on the stifle joint and satisfactory weight-bearing ambulation. Reluxation did not recur. PGR maybe a successful treatment for dogs with iatrogenically damaged and/or worn out patellar grooves.

Total hip replacement in two dogs with unsuccessful femoral head ostectomy.

An English setter (case 1) and a Tibetan mastiff (case 2) presented with intermittent weight-bearing lameness on the right hind limb when trotting. The dogs had a history of femoral head and neck ostectomy (FHNO). Orthopedic examination revealed pain and crepitus on the right hip joint. The dogs underwent total hip replacement (THR). At the 2-year (case 1) and 1-year (case 2) follow-up, both dogs had resumed normal activity without lameness. The muscle mass and range of motion were significantly improved in the affected hind limb. In conclusion, FHNO with poor functional outcomes can be successfully ameliorated with THR.