Felix M. Duerr

Comparison of Surgical Treatment Options for Cranial Cruciate Ligament Disease in Large‐Breed Dogs with Excessive Tibial Plateau Angle

OBJECTIVE To identify surgical techniques performed by veterinary surgeons for the treatment of cranial cruciate ligament disease in large-breed dogs with excessive tibial plateau angle (eTPA), compare their outcomes, identify risk factors for postoperative complications, and compare outcome and complication rate with tibial plateau leveling osteotomy (TPLO) in dogs without eTPA. STUDY DESIGN Multicenter, case-control study. ANIMALS eTPA group (TPA>or=35 degrees)=58 dogs (78 stifles); control group (TPA<or=30 degrees)=58 dogs (72 stifles). METHODS Control and eTPA group dogs were identified. Medical records, radiographic reviews, and pet-owner interviews were used to identify surgical treatments performed, their complications, and outcome. Odds ratios with 95% confidence intervals, chi(2) tests, and t-tests were calculated to discern differences between eTPA and control-group dogs. RESULTS TPLO was the most common treatment for eTPA. Owner-perceived outcome was superior for eTPA group dogs when TPLO resulted in TPA<or=14 degrees compared with those with postoperative TPA>14 degrees. Loss of tibial plateau leveling during convalescence was the most commonly observed major complication; addition of ancillary implants to TPLO significantly reduced its incidence. Postoperative complications were more common in dogs with eTPA than in dogs without eTPA; however, no difference in owner-perceived outcome was identified. CONCLUSIONS Surgical treatment of dogs with eTPA has a higher complication rate, but comparable outcome to that of dogs without eTPA. CLINICAL RELEVANCE Postoperative TPA<or=14 degrees and addition of ancillary implants are recommended when using TPLO to treat dogs with eTPA.Objective— To identify surgical techniques performed by veterinary surgeons for the treatment of cranial cruciate ligament disease in large-breed dogs with excessive tibial plateau angle (eTPA), compare their outcomes, identify risk factors for postoperative complications, and compare outcome and complication rate with tibial plateau leveling osteotomy (TPLO) in dogs without eTPA. Study Design— Multicenter, case–control study. Animals— eTPA group (TPA≥35°)=58 dogs (78 stifles); control group (TPA≤30°)=58 dogs (72 stifles). Methods— Control and eTPA group dogs were identified. Medical records, radiographic reviews, and pet-owner interviews were used to identify surgical treatments performed, their complications, and outcome. Odds ratios with 95% confidence intervals, χ2 tests, and t-tests were calculated to discern differences between eTPA and control-group dogs. Results— TPLO was the most common treatment for eTPA. Owner-perceived outcome was superior for eTPA group dogs when TPLO resulted in TPA≤14° compared with those with postoperative TPA>14°. Loss of tibial plateau leveling during convalescence was the most commonly observed major complication; addition of ancillary implants to TPLO significantly reduced its incidence. Postoperative complications were more common in dogs with eTPA than in dogs without eTPA; however, no difference in owner-perceived outcome was identified. Conclusions— Surgical treatment of dogs with eTPA has a higher complication rate, but comparable outcome to that of dogs without eTPA. Clinical Relevance— Postoperative TPA≤14° and addition of ancillary implants are recommended when using TPLO to treat dogs with eTPA.

Changes in pH of peritoneal fluid associated with carbon dioxide insufflation during laparoscopic surgery in dogs

OBJECTIVE To evaluate changes in pH of peritoneal fluid associated with CO2 insufflation during laparoscopy in dogs. ANIMALS 13 client-owned dogs and 10 purpose-bred teaching dogs. PROCEDURES Laparotomy was performed on control dogs; peritoneal fluid pH was measured at time of incision of the abdominal cavity (time 0) and 30 minutes later. Laparoscopic insufflation with CO2 was performed and routine laparoscopic procedures conducted on the teaching dogs. Insufflation pressure was limited to 12 mm Hg. Intraperitoneal fluid pH was measured by use of pH indicator paper at 4 time points. Arterial blood gas analysis was performed at the same time points. RESULTS Peritoneal fluid pH did not change significantly between 0 and 30 minutes in the control dogs. For dogs with CO2 insufflation, measurements obtained were a mean of 8.5, 24.5, 44.5, and 72.0 minutes after insufflation. The pH of peritoneal fluid decreased significantly between the first (7.825 +/- 0.350) and second (7.672 +/- 0.366) time point. Blood pH decreased significantly between the first (7.343 +/- 0.078), third (7.235 +/- 0.042), and fourth (7.225 +/- 0.038) time points. The PaCO2 increased significantly between the first (39.9 +/- 9.8 mm Hg) and fourth (54.6 +/- 4.4 mm Hg) time points. Base excess decreased significantly between the first and all subsequent time points. CONCLUSIONS AND CLINICAL RELEVANCE Pneumoperitoneum attributable to CO2 insufflation caused a mild and transient decrease in peritoneal fluid pH in dogs. Changes in peritoneal fluid associated with CO2 insufflation in dogs were similar to those in other animals.

High energy focused shock wave therapy accelerates bone healing. A blinded, prospective, randomized canine clinical trial.

OBJECTIVES To evaluate the influence of shock wave therapy (SWT) on radiographic evidence of bone healing after tibial plateau leveling osteotomy (TPLO). METHODS Healthy dogs between two to nine years of age that underwent TPLO were randomly assigned to receive either electro-hydraulic SWT (1,000 shocks) or sham treatment (SHAM). Treatment or SHAM was administered to the osteotomy site immediately postoperatively and two weeks postoperatively. Three blinded radiologists evaluated orthogonal radiographs performed eight weeks postoperatively with both a 5-point and a 10-point bone healing scale. Linear regression analysis was used to compare median healing scores between groups. RESULTS Forty-two dogs (50 stifles) were included in the statistical analysis. No major complications were observed and all osteotomies healed uneventfully. The median healing scores were significantly higher at eight weeks postoperatively for the SWT group compared to the SHAM group for the 10-point (p <0.0002) and 5-point scoring systems (p <0.0001). CLINICAL SIGNIFICANCE Shock wave therapy applied immediately and two weeks postoperatively led to more advanced bone healing at the eight week time point in this study population. The results of this study support the use of electro-hydraulic SWT as a means of accelerating acute bone healing of canine osteotomies. Additional studies are needed to evaluate its use for acceleration of bone healing following fracture, or with delayed union.

In vitro comparison of proximal ulnar osteotomy and distal ulnar osteotomy with release of the interosseous ligament in a canine model.

OBJECTIVE To determine the effect of proximal ulnar osteotomy (PUO), distal ulnar osteotomy (DUO), and DUO with release of the interosseous ligament (DOLR) on displacement of the proximal ulna at the radioulnar joint. STUDY DESIGN Experimental mechanical study. SAMPLE POPULATION Cadaveric, skeletally mature canine thoracic limb pairs (n=11). METHODS Thoracic limbs disarticulated at the elbow were randomly assigned to 1 of 2 groups: (A) limbs were tested with no treatment (NOTX), then with PUO; (B) limbs were tested with DUO followed by DOLR. A distraction force was applied to the proximal ulna with the distal limb secured in a frame, and displacement of the proximal ulnar segment at the radioulnar joint was recorded. RESULTS Mean displacement was 0.36 mm (95% confidence interval [CI]: 0-1.12 mm) in the NOTX group, 4.68 mm (95% CI: 3.82-5.55 mm) for PUO limbs, 0.95 mm (95% CI: 0.52-1.39 mm) for the DUO group, and 4.36 mm (95% CI: 3.71-5.02 mm) for the DOLR group. Mean ulnar displacement of the DOLR group was significantly different compared with the DUO group, but there was no significant difference between the PUO and DOLR groups. CONCLUSIONS No significant difference was observed in displacement of the proximal ulnar segment after DOLR compared with PUO.

Evaluation of a novel canine activity monitor for at-home physical activity analysis

BackgroundAccelerometers are motion-sensing devices that have been used to assess physical activity in dogs. However, the lack of a user-friendly, inexpensive accelerometer has hindered the widespread use of this objective outcome measure in veterinary research. Recently, a smartphone-based, affordable activity monitor (Whistle) has become available for measurement of at-home physical activity in dogs. The aim of this research was to evaluate this novel accelerometer. Eleven large breed, privately owned dogs wore a collar fitted with both the Whistle device and a previously validated accelerometer-based activity monitor (Actical) for a 24-h time period. Owners were asked to have their dogs resume normal daily activities. Total activity time obtained from the Whistle device in minutes was compared to the total activity count from the Actical device. Activity intensity from the Whistle device was calculated manually from screenshots of the activity bars displayed in the smartphone-application and compared to the activity count recorded by the Actical in the same 3-min time period.ResultsA total of 3740 time points were compared. There was a strong correlation between activity intensity of both devices for individual time points (Pearson’s correlation coefficient 0.81, p < 0.0001). An even stronger correlation was observed between the total activity data between the two devices (Pearson’s correlation coefficient 0.925, p < 0.0001).ConclusionsActivity data provided by the Whistle activity monitor may be used as an objective outcome measurement in dogs. The total activity time provided by the Whistle application offers an inexpensive method for obtaining at-home, canine, real-time physical activity data. Limitations of the Whistle device include the limited battery life, the need for manual derivation of activity intensity data and data transfer, and the requirement of Wi-Fi and Bluetooth availability for data transmission.

Assessment of on-screen measurements, magnification, and calibration in digital radiography

OBJECTIVE To compare calibration methods for digital radiography in terms of measurement accuracy and interobserver variability. DESIGN Prospective study. SAMPLE Digital radiographic images of a 155-mm-long Steinmann pin. PROCEDURES Measurement of pin length on digital radiographs was determined with a 25.4-mm-diameter calibration ball and commercially available software program via 3 calibration methods (ie, no calibration, autocalibration, and manual calibration). Digital radiographs of the calibration ball and pin were obtained with each placed at various vertical heights from the table (7 heights) and horizontal distances from the center of the beam (4 distances). Measurements of pin length on digital radiographs were made by 4 observers who were blinded to the orientation of the calibration ball and pin. RESULTS Pin lengths obtained by each calibration method were significantly different from each other and from the true value. Manual calibration was the most accurate. There was no significant interobserver variability in measurements. There was no significant change in measurements when the calibration ball was moved horizontally, but pin length measurements changed significantly when the ball was moved vertically (away from the table) with an approximate magnification error of 1% per centimeter of distance between the calibration ball and pin. CONCLUSIONS AND CLINICAL RELEVANCE For digital radiography, manual calibration is recommended to achieve the most accurate measurements. Ideally, the calibration ball should be placed at the same vertical height as the object to be measured; however, if this cannot be achieved, the magnification error can be expected to be approximately 1% per centimeter of distance.

The method of attachment influences accelerometer-based activity data in dogs

BackgroundAccelerometer-based activity monitoring is a promising new tool in veterinary medicine used to objectively assess activity levels in dogs. To date, it is unknown how device orientation, attachment method, and attachment of a leash to the collar holding an accelerometer affect canine activity data. It was our goal to evaluate whether attachment methods of accelerometers affect activity counts. Eight healthy, client-owned dogs were fitted with two identical neck collars to which two identical activity monitors were attached using six different methods of attachment. These methods of attachment evaluated the use of a protective case, positioning of the activity monitor and the tightness of attachment of the accelerometer. Lastly, the effect of leash attachment to the collar was evaluated. For trials where the effect of leash attachment to the collar was not being studied, the leash was attached to a harness. Activity data obtained from separate monitors within a given experiment were compared using Pearson correlation coefficients and across all experiments using the Kruskal-Wallis Test.ResultsThere was excellent correlation and low variability between activity monitors on separate collars when the leash was attached to a harness, regardless of their relative positions. There was good correlation when activity monitors were placed on the same collar regardless of orientation. There were poor correlations between activity monitors in three experiments: when the leash was fastened to the collar that held an activity monitor, when one activity monitor was housed in the protective casing, and when one activity monitor was loosely zip-tied to the collar rather than threaded on using the provided metal loop. Follow-up, pair-wise comparisons identified the correlation associated with these three methods of attachment to be statistically different from the level of correlation when monitors were placed on separate collars.ConclusionsWhile accelerometer-based activity monitors are useful tools to objectively assess physical activity in dogs, care must be taken when choosing a method to attach the device. The attachment of the activity monitor to the collar should utilize a second, dedicated collar that is not used for leash attachment and the attachment method should remain consistent throughout a study period.

Comparison of owner satisfaction between stifle joint orthoses and tibial plateau leveling osteotomy for the management of cranial cruciate ligament disease in dogs

OBJECTIVE To compare owner satisfaction between custom-made stifle joint orthoses and tibial plateau leveling osteotomy (TPLO) for the management of medium- and large-breed dogs with cranial cruciate ligament disease (CCLD). DESIGN Owner survey. SAMPLE 819 and 203 owners of dogs with CCLD that were managed with a custom-made stifle joint orthosis or TPLO, respectively. PROCEDURES Client databases of an orthosis provider and veterinary teaching hospital were reviewed to identify potential survey respondents. An online survey was developed to evaluate owner-reported outcomes, complications, and satisfaction associated with the nonsurgical (orthosis group) and surgical (TPLO group) interventions. Survey responses were compared between groups. RESULTS The response rate was 25% (203/819) and 37% (76/203) for the orthosis and TPLO groups, respectively. The proportion of owners who reported that their dogs had mild or no lameness and rated the intervention as excellent, very good, or good was significantly greater for the TPLO group than for the orthosis group. However, ≥ 85% of respondents in both groups reported that they would choose the selected treatment again. Of 151 respondents from the orthosis group, 70 (46%) reported skin lesions associated with the device, 16 (11%) reported that the dog subsequently underwent surgery, and 10 (7%) reported that the dog never tolerated the device. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated high owner satisfaction rates for both interventions. Owners considering nonsurgical management with an orthosis should be advised about potential complications such as persistent lameness, skin lesions, patient intolerance of the device, and the need for subsequent surgery.

Assessment of novel digital and smartphone goniometers for measurement of canine stifle joint angles

OBJECTIVE To evaluate accuracy and reliability of 3 novel goniometers for measurement of canine stifle joint angles and compare the results with those obtained with a universal goniometer (UG). SAMPLE 8 pelvic limbs from 4 canine cadavers. PROCEDURES Each limb was secured to a wooden platform at 3 arbitrarily selected fixed stifle joint angles. Goniometry was performed with 2 smartphone-based applications (novel goniometers A and B), a digital goniometer (novel goniometer C), and a UG; 3 evaluators performed measurements in triplicate for each angle with each device. Results were compared with stifle joint angle measurements on radiographs (used as a gold standard). Accuracy was determined by calculation of bias and total error, coefficients of variation were calculated to estimate reliability, and strength of linear association between radiographic and goniometer measurements was assessed by calculation of correlation coefficients. RESULTS Mean coefficient of variation was lowest for the UG (4.88%), followed by novel goniometers B (7.37%), A (7.57%), and C (12.71%). Correlation with radiographic measurements was highest for the UG (r = 0.97), followed by novel goniometers B (0.93), A (0.90), and C (0.78). Constant bias was present for all devices except novel goniometer B. The UG and novel goniometer A had positive constant bias; novel goniometer C had negative constant bias. Total error at 50° and 100° angles was > 5% for all devices. CONCLUSIONS AND CLINICAL RELEVANCE None of the devices accurately represented radiographically measured stifle joint angles. Additional veterinary studies are indicated prior to the use of novel goniometers in dogs.

Piezoelectric Surgery - A Novel Technique for Laminectomy

ABSTRACT Objective: Piezoelectric surgery is a novel technology that allows for the osteotomy of mineralized tissue with less risk of damaging underlying soft tissue structures. This selective cutting increases the safety of osteotomies performed in close vicinity to delicate structures such as dura mater, blood vessels, and neural tissue. This study aimed to develop and describe the technique of piezoelectric surgery for dorsal laminectomy and to assess its clinical safety in normal sheep. Methods: A piezoelectric, dorsal laminectomy technique was developed using ovine cadavers. Following technique development, six live sheep underwent a piezoelectric (n = 6) two-level dorsal laminectomy at L2-L3 and L4-L5 (PiezoL2-3,4-5), and another 30 live sheep underwent a three-level laminectomy at L1, L3, and L5 (PiezoL1,3,5) for a total of 102 laminectomy sites. Surgery time and postoperative complications were recorded. Results: Dorsal laminectomy was safely and accurately performed in 35/36 study sheep using a Piezoelectric surgical instrument. No dural tears were noted in any animal. Non-ambulatory paraparesis in one study sheep (PiezoL1,3,5) led to euthanasia at 48 hr and only mild epidural hematoma was noted on necropsy. No other major postoperative complications were observed in any of the animals. Subjectively, PiezoL was easy to perform and with a rapid learning curve. Mean surgery time was 105 min (range: 75–165 min; median: 97.5) for PiezoL2-3,4-5 and 93 minutes (range 55–100 min; median: 67.5) for PiezoL1,3,5. Conclusions: Based on our study, PiezoL is considered a safe and viable technique for performing ovine dorsal laminectomy in the preclinical research setting.