Interventional computer tomography -a new dimension in horse medicine -Part 1: CT assisted drilling and filling of subchondral cystic lesions in the horse The computed tomography is indispensable to secondary diagnostic in the head and neck area as well as on the limbs of the horse and is used routinely in specialized equine clinics. With this technique a super positional free representation of body parts is possible in different sectional levels and in three-dimensional images. The surgical treatment of subchondral cystic lesions (SCL) in the horse consists of surgical debridement and possibly in the replenishment of the cyst cavity in order to achieve revascularization and bone fusion of the damaged area. Depending on localization, shape and size of the cyst this is done via an arthroscopic or arthrotomic access. As an alternative to intraarticular surgical techniques the subchondral cystic lesions are classically treated by transcortical drilling via radiological control or fluoroscopy. These navigation methods, however, are severely limited due to the only two-dimensional imaging and the obtained information is often not satisfactory for the surgeon. The clinical use of CT-assisted surgical treatment of subchondral cystic lesions in horses (SCL with connection to the carpal joint, fetlock joint, pastern joint and navicular bursa) is shown by various examples. Via three-dimensional computed tomographic control, a gradual drilling of SCL was performed, afterwards the debridement of the cyst content, flushing and filling the cyst cavity and the drill hole. As a result, this surgical technique may also be referred as a sensible alternative to an arthroscopic or arthrotomic approach for difficult to access SCL in the joint region in horses. Further clinical studies are required in order to prove, to what extent the success rate actually improves in comparison to conventional techniques.

SummaryAn eight-year-old Hanoverian gelding was presented with a progressively growing mass in the left cranial region of the saddle area and a history of riding problems. A firm, poorly circumscribed, non-painful tissue was palpable. Diagnostic imaging revealed a calcified mass in the depth of the swelling. This calcified mass was excised out of the musculus longissimus thoracis under general anesthesia. Post surgery the horse developed a non-healing and intermittendly profusely bleeding wound. During the treatment of this non-healing wound tissue samples were sent to a laboratory for histopathological and immunohistochemical analysis. The analysis confirmed a fibrosarcoma. The horse was euthanized because of a very poor prognosis.

Zusammenfassung: Die Verwendung der computertomographischen Schnittbildtechnik hat sich in der Pferdemedizin bewährt und wird in spezialisierten Pferdekliniken routinemäßig eingesetzt. In der orthopädischen Diagnostik wird diese Technik am Vorderbein des Pferdes normalerweise an der distalen Gliedmaße bis zur Karpalregion eingesetzt. The use of computer tomography has proved successful in equine medicine and surgery and is used routinely in specialized equine clinics. In orthopedic diagnostics of the equine forelimb, this technology is most commonly used on the distal limb up to the carpal region. The surgical therapy of subchondral cystic lesions (SCL) in horses involves surgical debridement and if necessary even filling of the cystic cavities to achieve a revascularization and ossification of the defect. This is done via arthroscopy or arthrotomy depending on the localization. Alternatively the technique of transcortical drilling of SCL either under radiographic or fluoroscopic control has been described.. This paper describes the clinical situation and the CT-guided diagnosis in three horses with subchondral cystic lesions in the proximal radius. All horses were clinically examined including diagnostic anesthesia and radiographic images in more than one plane. However, in all horses only the CT-images showed a thin communicating tract to the elbow joint and multiple micro fractures in the proximal radius. The subchondral cystic lesions were subsequently approached via transcortical drilling under radigraphic control, debridement and flushing using specially manufactured surgical instruments, followed by filling the cystic lesions and drilled hole with bone cement. In conclusion the exactly preoperative CT-diagnosis and operation planning with extra articular bone drilling and filling of subchondral lesions serves as a useful alternative method to arthroscopic or arthrotomic procedure. The advantage of this operative procedure is seen in the conservation of the articular cartilage and the immediate stabilization of the subchondral bone. All three horses are healthy and without lameness after this intervention. One horse competes in tournaments at intermediate level, another horse takes part in international show-jumping and the third one in advanced level dressage.

ZusammenfassungEs werden die Möglichkeiten der sonographischen Darstellbarkeit verschiedener Strukturen der Schulterregion des Pferdes erarbeitet, Standarduntersuchungsebenen vorgeschlagen und den Ultraschallbildern angepasste anatomische Vergleichsschnitte erstellt. Außerdem wird ein neuer Punkt zur Arthrozentese vorgestellt und eine umstrittene Verbindung zwischen Bursa intertubercularis und Schultergelenk über-prüft. Die Untersuchungen erfolgten an 23 Gliedmaßen unter Einsatz eines 6,0 / 8,0 MHz Linear-und eines 5,0 / 7,5 MHz Mehrfachwinkelsektorschallkopfes.Schlüsselwörter: Ultraschall, Schultergelenk, Bizepssehne, Bursa intertubercularis, PferdThe sonographic representation of the shoulder region in horses with special consideration of clinically relevant structuresThe possibilities of sonographic representation of various structures in the shoulder region of the horse are elaborated, standardized diagnostical planes suggested and comparative anatomical preparations adapted to the ultrasound pictures made. Furthermore, a new aspect of arthrocentesis is presented and the controversial connection between the bicipital bursa and the shoulder joint is examined. In vivo ultrasound was performed on 23 limbs using a linear probe (6,0 or 8,0 MHz) and a multiple angle sector probe (5,0 or 7,5 MHz). For the sonographical examinations, the shoulder region was divided into 4 diagnostic areas with on overall of 16 diagnostic planes. These diagnostical planes and the structures associated with them were selected for their clinical relevance and their relation to easily palpable anatomical spots in order to ensure an easy reproducibility. The tendon of the biceps brachii muscle was evaluated in its full extension from its origin at the supraglenoid tubercle, along the shoulder joint and the intertubercular groove, up to its transition into the muscle, as well as, the underlying bursa. Furthermore, the 2 terminal tendons of the supraspinatus muscle were examined. The visible shoulder joint portions of the lateral shoulder region (joint capsule, synovial space, scapula, and head of the humerus) were evaluated and the terminal tendon of the infraspinatus muscle as well as the underlying bursa were represented. In the scapula region the scapular spine and the area around the turning point of the suprascapular nerve were examined. All mentioned structures with the exception of the scapular spine were measured by means of a scanner-integrated measuring device. Postmortal arthrocentesis and colouring of the joint was performed on one shoulder of each of the 18 euthanized horses. Hereby, a position just caudally to the infraspinatus tendon, ca. 1 cm caudally to the centre of the caudal eminence of the greater tubercle, was chosen. A methyl blue coloration was used to test the existence of a controversially discussed connection between the shoulder joint and the intertubercular bursa. In one of the 18 examined cases the bursa was also coloured. A connection between these two synovial structures can therefore not be ruled out. Sono...

The possibilities for imaging soft tissue structures, especially fluid-filled cavities such as articulations, bursae or tendon sheaths, have been improved markedly by sonography in recent years. Ultrasonic examinations were performed on the common tendon sheath of the musculus flexor hallucis longus and the musculus tibialis caudalis, from the medioplantar aspect of the tarsus, in 12 sound adult draft- and warm blood horses, and in 5 animals with a distended common sheath. The diagnostic precision of the sonographic examination of the tendon sheath is excellent and is superior to conventional radiography. A nuclear magnetic resonance tomogram of an isolated equine tarsus is presented for comparison method.