Page 92 - Clinical Manual of Small Animal Endosurgery

80 Clinical Manual of Small Animal Endosurgery

needle placement, the joint is distended with lactated Ringer’s solution
containing 2–3 ml of 7.5% ropivacaine (not exceeding 2 mg/kg) and
0.1 mg/kg morphine for a few minutes prior to further intervention. The
arthroscope portal is located using a 22–19-gauge 40–50 mm needle
inserted through the skin and soft tissues just craniodistal to the distal
tip of the acromion, with the needle directed perpendicular to the skin
and the long axis of the limb. The assistant applies traction to the limb
to open the joint space easing this process and fluid egress from the
needle confirms intra-articular placement. A small skin incision is created
adjacent to the locator needle and the arthroscope cannula with blunt
obturator is inserted firmly. A ‘popping’ sensation accompanies penetra-
tion of the joint capsule and fluid egress from the cannula following
obturator removal confirms intra-articular insertion. During insertion of
the arthroscope cannula, the surgeon’s fingers brace the scope against
the skin to prevent over insertion and damage to the shoulder. The
arthroscope is inserted, the fluid-ingress line is connected to the scope
cannula and fluid flow is activated. A 19-gauge or larger needle should
be inserted, replacing the small-gauge needle used to distend the joint or,
alternatively, an instrument cannula may be used as the egress portal.
The entire shoulder joint should be investigated using a systematic
approach, documenting pathological changes on the appropriate chart
(see Table 2.3, arthroscopic assessment of the shoulder). Following thor-
ough inspection of the joint space and intra-articular structures, the
instrument portal is created approximately 1–3 cm from the arthroscope
portal, depending on the size of the dog. A 40–50 mm 22–19-gauge
needle is inserted into the articular space. The needle should be inserted
almost parallel to the arthroscope, aiming to bring the needle tip just in
front of the scope tip, which should be rotated with the view towards
the needle. An instrument portal is created by incising the skin with a
scalpel and inserting a switching stick and cannula through a soft-tissue
tunnel adjacent to the locator needle or alternatively, following the skin
incision, a soft-tissue tunnel is created by opening the tips of Metzen-
baum scissors to create a large instrument portal.

Arthroscopically assisted surgery for OCD of the shoulder
In most cases, the cartilaginous flap is most evident caudally on the
humeral head and has an attachment to normal cartilage at its cranial
aspect (Fig. 3.13). The surgeon should decide between two surgical
techniques: removal en masse or piecemeal removal. Smaller flaps are
better suited to removal en masse whereas large ones tend to fragment
and therefore are perhaps better suited to removal piecemeal using an
instrument cannula.
The free edge of the flap is gently elevated with a probe or switching
stick and a small area of attachment should be preserved to prevent the
flap floating free. A large grasping forceps is inserted and the flap is firmly
grasped along the length of the jaws of the forceps. Twisting the forceps