Page 55 - Clinical Manual of Small Animal Endosurgery

Diagnostic Arthroscopy 43

Fig. 2.13 Triangulation device fitted to the arthroscope sleeve. The sharp
switching stick shows triangulation.

Aiming device
Introducing the instruments into the arthroscopic view is technically
challenging for the novice arthroscopist and for each joint approached
during the learning experience. Effective arthroscopic surgery requires
achieving a suitable direction for the instruments that gives an arthro-
scopic view of the instrument tip enabling intuitive control, while ena-
bling manipulation of the instrument handle without interference with
the arthroscope. Initially it is challenging to achieve suitable placement
of the instruments and an aiming device removes the error in this pro-
cedure. The aiming device clips onto the arthroscopic cannula sleeve and
gives a fixed triangulation for the instrument (Fig. 2.13). It is necessary
to attach the aiming device to the cannula at the correct height from the
tip before the cannula is inserted into the joint to ensure that the scope
tip and the instrument meet at the field of view.

Joint distractor
Improved access to small joints is facilitated by distraction or leverage
of the joint, stretching tissues and opening the joint cavity. Distraction
can be achieved by bracing the joint against a fulcrum, like a sandbag
or a customised brace, while an assistant applies directed force to the
distal limb. Distraction of the stifle joint can be also be achieved using
a custom-made distraction device (Fig. 2.14) that engages percutaneously
placed pins inserted into the subchondral bone on adjacent sides of the
joint. The threaded rod of the distractor spans the joint and progressive
tightening of the adjustment wheel tensions the soft tissues of the joint