Otto I. Lanz

Successful Treatment of a Large Soft Tissue Sarcoma With Irreversible Electroporation

Introduction Irreversible electroporation (IRE) is a promising technique for the focal treatment of pathologic tissues that involves placing minimally invasive electrodes within the targeted region. A series of short, intense electric pulses are then applied to destabilize the cell membrane, presumably by creating nanopores, inducing cell death in a nonthermal manner. The unique therapeutic mechanism of IRE does not rely on tissue temperature changes, as with hyperthermic or cryoablative procedures. Therefore, IRE preserves the extracellular matrix, major tissue vasculature, and other sensitive structures. Treated regions resolve rapidly, with submillimeter resolution between treated and unaffected cells, and are predictable with numerical modeling. Treatments promote an immune response, are unaltered by blood flow, can be administered quickly (approximately 5 minutes), and can be visualized in real time. IRE has been studied extensively in healthy tissue, and tumors have been treated with IRE in mice. IRE has been attempted in humans for prostate, lung, kidney, and liver cancers. Human treatments revealed negligible postablation pain and the ability to apply the pulses in proximity to vital structures. Overall, assessment of the therapeutic efficacy of IRE remains in its infancy. We hypothesize that IRE treatments can be designed and implemented to successfully treat soft tissue malignancies, including large and complex tumors, a crucial step for translation of the technology into routine clinical use. Here we report our treatment of a focal histiocytic sarcoma of the coxofemoral joint in a canine patient. Follow-up examinations demonstrated prolonged relief of cancerassociated pain, preservation of pelvic limb function, and complete tumor regression 6 months after initial treatment.

Laparoscopic ovariohysterectomy in nine dogs

Minimally invasive surgery has been found in humans to reduce pain, incidence of infections, and duration of hospitalization. Minimally invasive procedures are also being described in veterinary medicine. Laparoscopic ovariohysterectomy (OHE) was performed on nine, healthy, intact female dogs using a Harmonic scalpel. Creatine kinase values were determined both before and 12 hours following the laparoscopic OHE; the magnitude of the difference between preoperative and postoperative creatine kinase values did not correlate with length of operative time, length of incisions, or amount of hemorrhage. Complications included one dog that had an omental herniation that was primarily repaired and one dog with seroma formation. Median surgical time for all dogs was 60 minutes (range, 35 to 100 minutes).

Surgery of the ear and pinna

There are several disease processes of the ear and pinna that warrant surgical intervention. This article reviews surgical anatomy and common surgical procedures of the ear and pinna, including aural hematomas, lateral wall resection, vertical ear canal resection, total ear canal ablation and lateral bulla osteotomy, partial pinna resection, and feline inflammatory polyps. The clinical signs, diagnosis, and surgical treatment along with potential complications for each disease process are discussed.

A biomechanical comparison of 3.5 locking compression plate fixation to 3.5 limited contact dynamic compression plate fixation in a canine cadaveric distal humeral metaphyseal gap model.

3.5 locking compression plate (LCP) fixation was compared to 3.5 limited contact dynamic compression plate (LC-DCP) fixation in a canine cadaveric, distal humeral metaphyseal gap model. Thirty paired humeri from adult, large breed dogs were separated into equal groups based on testing: static compression, cyclic compression, and cyclic torsion. Humeral constructs stabilised with LCP were significantly stiffer than those plated with LC-DCP when loaded in static axial compression (P = 0.0004). When cyclically loaded in axial compression, the LCP constructs were significantly less stiff than the LC-DCP constructs (P = 0.0029). Constructs plated with LCP were significantly less resistant to torsion over 500 cycles than those plated with LC-DCP (P<0.0001). The increased stiffness of LCP constructs in monotonic loading compared to constructs stabilised with non-locking plates may be attributed to the stability afforded by the plate-screw interface of locking plates. The LCP constructs demonstrated less stiffness in dynamic testing in this model, likely due to plate-bone offset secondary to non-anatomic contouring and occasional incomplete seating of the locking screws when using the torque-limiting screw driver. Resolution of these aspects of LCP application may help improve the stiffness of fixation in fractures modeled by the experimental set-up of this investigation.

Lumbosacral and pelvic injuries

Pelvic fractures are commonly observed in cats after automobile-induced trauma and frequently affect other organ systems. An organized systematic approach should be followed in the evaluation of pelvic fractures. Common pelvic fracture patterns observed in cats include pubic fractures in combination with unilateral ilial fractures, unilateral sacroiliac luxations, bilateral sacroiliac luxations, and contralateral ilial body fractures. Narrowing of the pelvic canal may preclude normal passage of feces and result in megacolon. Timely and precise surgical intervention is necessary so as to impart a favorable prognosis.

Canine Spinal Nephroblastoma: Long‐Term Outcomes Associated with Treatment of 10 Cases (1996–2009)

OBJECTIVE To report clinical outcome associated with treatment of canine spinal cord nephroblastoma (CSN). STUDY DESIGN Case series. ANIMALS Dogs (n=10) with histopathologically confirmed CSN. METHODS Records of dogs with CSN were reviewed and clinicopathologic, diagnostic imaging, treatment, outcome, and survival data were collected. RESULTS CSN resulted in clinical signs of chronic, progressive T3-L3 myelopathy in young, large breed dogs, with an overrepresentation of German Shepherd Dogs (n=4). All CSN were located between T9 and L2. Dogs treated with cytoreductive surgery (n=6) or radiotherapy (1) survived longer (median, 374 days; range, 226-560 days) than dogs treated palliatively (3; median, 55 days; range, 38-176 days). Tumors confined to an intradural-extramedullary (ID-EM) location were associated with superior survival (n=6; median, 380 days; range, 176-560 days) than tumors with intramedullary (IM) involvement (n=4; median, 140 days; range, 38-269 days). Treatment resulted in temporary improvement in neurologic function in 9 dogs, including all dogs treated surgically, but local disease progression resulted in death of 8 dogs. CONCLUSIONS Results of this observational study suggest that surgical cytoreduction and radiotherapy are effective at improving survival in dogs with CSN, and that ID-EM tumors may be associated with a more favorable prognosis than IM neoplasms.

The effects of a novel lateral extracapsular suture system on the kinematics of the cranial cruciate deficient canine stifle

OBJECTIVE To evaluate the relative position of the femur and tibia in cranial cruciate ligament-intact stifles, cranial cruciate ligament-deficient stifles, and cruciate-deficient stifles following lateral extracapsular suture system (LESS) stabilization under load at specific joint angles. STUDY DESIGN In vitro biomechanical study. METHODS Twenty pelvic limbs from 11 dogs were used to evaluate the relative position of the femur and tibia between three stifle conditions (cranial cruciate ligament-intact, cranial cruciate ligament-deficient, and LESS-stabilized) at a load of 30% of body weight and stifle angles of 125°, 135°, and 145° using electromagnetic tracking sensors. RESULTS Cranial cruciate ligament-deficient stifles had significantly greater (p <0.0001) cranial displacement and internal rotation of the tibia relative to the femur than cranial cruciate ligament-intact or LESS stifles at all stifle angles. Cranial displacement of the tibia relative to the femur for cranial cruciate ligament-intact and LESS stifles were not significantly different from one another at a stifle angle of 125°, but were significantly different at stifle angles of 135° (p = 0.0182) and 145° (p = 0.0012). There was no significant difference in internal rotation of the tibia relative to the femur between the cranial cruciate ligament-intact and LESS stifles at any of the stifle angles. CLINICAL SIGNIFICANCE The LESS procedure effectively decreased cranial tibial displacement and eliminated internal rotation of the tibia relative to the femur in the cranial cruciate ligament-deficient stifles at stifle angles of 125°, 135°, and 145° in vitro.

Recurrence of spontaneous lung lobe torsion in a pug

Lung lobe torsion (LLT) results from a displacement and twisting of a lung lobe around its bronchovascular pedicle. This relatively rare disorder affects dogs, cats, and humans. Etiologies include primary (i.e., spontaneous) and secondary torsion due to thoracic trauma, pleural space disease, thoracic surgery, pulmonary parenchyma disease, and diaphragmatic hernia repair. Although both spontaneous and secondary torsion have been described in small-breed dogs, a spontaneous LLT followed by recurrence of a spontaneous LLT > 2 years later has not been documented. This article describes the presentation, diagnosis, management, and outcome of a pug with recurrent spontaneous LLT.

Noninvasive Blood Perfusion Measurements of an Isolated Rat Liver and an Anesthetized Rat Kidney

A simple, cost effective, and noninvasive blood perfusion system is tested in animal models. The system uses a small sensor to measure the heat transfer response to a thermal event (convective cooling) imposed on the tissue surface. Heat flux data are compared with a mathematical model of the tissue to estimate both blood perfusion and thermal contact resistance between the tissue and the probe. The perfusion system was evaluated for repeatability and sensitivity using isolated rat liver and exposed rat kidney tests. Perfusion in the isolated liver tests was varied by controlling the flow of the perfusate into the liver, and the perfusion in the exposed kidney tests was varied by temporarily occluding blood flow through the renal artery and vein. The perfusion estimated by the convective perfusion probe was in good agreement with that of the metered flow of the perfusate into the liver model. The liver tests indicated that the probe can be used to detect small changes in perfusion (0.005 ml/ml/s). The probe qualitatively tracked the changes in the perfusion in the kidney model due to occlusion of the renal artery and vein.

A Phantom Tissue System for the Calibration of Perfusion Measurements

A convenient method for testing and calibrating surface perfusion sensors has been developed. A phantom tissue model is used to simulate the nondirectional blood flow of tissue perfusion. A computational fluid dynamics (CFD) model was constructed in Fluent(R) to design the phantom tissue and validate the experimental results. The phantom perfusion system was used with a perfusion sensor based on clearance of thermal energy. A heat flux gage measures the heat flux response of tissue when a thermal event (convective cooling) is applied. The blood perfusion and contact resistance are estimated by a parameter estimation code. From the experimental and analytical results, it was concluded that the probe displayed good measurement repeatability and sensitivity. The experimental perfusion measurements in the tissue were in good agreement with those of the CFD models and demonstrated the value of the phantom tissue system.