Non-invasive evaluation of skin tension lines with elastic waves.

BACKGROUND: Since their discovery by Karl Langer in the 19th Century, Skin Tension Lines (STLs) have been used by surgeons to decide the location and orientation of an incision. Although these lines are patient-specific, most surgeons rely on generic maps to determine their orientation. Beyond the imprecise pinch test, there remains no accepted method for determining STLs in vivo. METHODS: (i) The speed of an elastic motion travelling radially on the skin of canine cadavers was measured with a commercial device called the Reviscometer® . (ii) Similar to the original experiments conducted by Karl Langer, circular excisions were made on the skin and the geometric changes to the resulting wounds and excised samples were used to determine the orientation of STLs. RESULTS: A marked anisotropy in the speed of the elastic wave travelling radially was observed. The orientation of the fastest wave was found to correlate with the orientation of the elongated wound (P<0.001, R2 =74%). Similarly, the orientation of fastest wave was the same for both in vivo and excised isolated samples, indicating that the STLs have a structural basis. Resulting wounds expanded by an average area of 9% (+16% along STL and -10% across) while excised skin shrunk by an average area of 33% (23% along STL and 10% across). CONCLUSION: Elastic surface wave propagation has been validated experimentally as a robust method for determining the orientation of STLs non-destructively and non-invasively. This study has implications for the identification of STLs and for the prediction of skin tension levels, both important factors in both human and veterinary reconstructive surgery.

Thoracic bite trauma in dogs and cats: a retrospective study of 65 cases.

OBJECTIVES: To report a case series of thoracic bite trauma in dogs and cats and to evaluate risk factors for mortality. METHODS: A retrospective study concerning thoracic bite wounds in dogs and cats was performed. Lesions were categorized by depth of penetration: no wound, superficial, deep or penetrating. Thoracic radiographic reports were reviewed. Lesion management was classified as non-surgical, wound exploration, or explorative thoracotomy. RESULTS: Sixty-five cases were collected. Twenty-two percent of patients with normal respiratory patterns showed thoracic radiographic lesions. Respiratory distress was not correlated with mortality. Twenty-eight patients were presented with superficial wounds and 13 with deep wounds. Eight patients exhibited penetrating wounds. Radiographic lesions were observed in 77% of dogs and 100% of cats. Explorative thoracotomy was performed in 28% of patients, and surgical wound exploration in 17.2%. With the exception of skin wounds, thoracic wall discontinuity was the most frequent lesion. Thoracotomy was associated with increased length of hospitalisation but was not correlated with mortality. The mortality rate was 15.4%. No studied factor correlated with mortality, and the long-term outcomes were excellent. CLINICAL SIGNIFICANCE: A penetrating injury, more than three radiographic lesions, or both together seemed to be indicative of the need for a thoracotomy. In the absence of these criteria, systematic bite wound explorative surgery is recommended, with extension to thoracotomy if thoracic body wall disruption is observed.

Removal of oesophageal foreign bodies: comparison between oesophagoscopy and oesophagotomy in 39 dogs.

OBJECTIVES: To compare complication rates and outcomes after removal of oesophageal foreign bodies by endoscopy or by oesophagotomy. METHODS: Retrospective evaluation of medical records of dogs with oesophageal foreign bodies treated by endoscopy and/or oesophagotomy. Postoperative clinical signs, management, length of hospitalisation, type and rate of complications, and time interval to return to eating conventional diet were compared. RESULTS: Thirty-nine dogs diagnosed with oesophageal foreign bodies between 1999 and 2011 were included in the study. Most common breeds included West Highland white terrier, Jack Russell terrier and shih-tzu. Successful endoscopic removal was possible in 24 out of 32 cases (Group 1), while surgical removal was successful in 15 out of 15 cases (7 of which had unsuccessful attempts at endoscopic removal) (Group 2). Length of hospitalisation, time to removal of gastrostomy tube and time to eat conventional diet did not differ between the groups. After foreign body removal, the incidence of oesophagitis, oesophageal stricture and perforation observed during repeated endoscopy were similar between the groups. CLINICAL SIGNIFICANCE: In this retrospective study, removal of oesophageal foreign bodies either by oesophagoscopy or oesophagotomy had a similar outcome.

Comparison of radiographic measurements of the patellar tendon-tibial plateau angle with anatomical measurements in dogs. Validity of the common tangent and tibial plateau methods.

OBJECTIVE: To evaluate the validity of the common tangent and conventional tibial plateau angle methods for measuring the patellar tendon angle (PTA) in dogs. METHODS: Radiographs of cadaveric stifles (n = 20) placed at 135° in true lateral position were obtained to measure the PTA with both methods. A Kirschner wire was inserted perpendicularly to the patellar tendon at its insertion on the tibia and the stifle was dissected. Two Kirschner wires were then used to identify the anatomical landmarks of the tibial plateau. A digital image was obtained of the proximal tibia in true lateral position. Six blinded observers measured each PTA digitally while the anatomical PTA was determined by an independent blinded observer from the angle between the line representing the tibial plateau and the Kirschner wire representing the perpendicular to the patellar tendon. The agreement between the methods was determined statistically from an intraclass correlation coefficient (ICC). RESULTS: The global ICC for the common tangent method (0.44) and for the conventional method (0.4) indicated that their overall validity is poor. The measurements obtained by common tangentmethod and conventional method were respectively below and above the anatomical measurements. The reproducibility of the PTA measurements based on images of the dissected stifles was very good. CLINICAL SIGNIFICANCE: Both the common tangent and conventional methods show poor concordance with the anatomical measurement of PTA. Further studies are needed to determine if errors in measurements affect the clinical outcome.