Page 19 - BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery, 2nd Edition

BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

Mallet and osteotome absorbable suture material (e.g. poliglecaprone 25 or poly-
dioxanone) is recommended because it produces low
A mallet and osteotome are needed to separate the two tissue drag and does not have interstices that can poten-
VetBooks.ir (e.g. during mandibulectomy, maxillectomy, dorsal rhino- tially harbour bacteria. Polydioxanone provides extended
mandibles at the symphysis or to make precise bone cuts
support for 1–2 months and may be chosen in a compro-
tomy or ventral bulla osteotomy).
mised patient when it is suspected that oesophageal heal-
ing may be prolonged.
Rib shears Repair of a diaphragmatic rupture and intercostal thora-
It is occasionally necessary to remove a rib to improve the cotomy closure necessitate the use of suture material that
access obtained via an intercostal thoracotomy. Standard provides prolonged wound support, such as polydioxanone
bone cutters, used with care, are capable of performing or non-absorbable monofilament nylon. Median sternotomy
this task. However, rib shears are available that have a closure must be very secure and is achieved using large-
single blade that apposes a curved protective edge, which gauge polydioxanone or stainless steel wire sutures, which
reduces the risk of iatrogenic thoracic damage. have the highest tensile strength of all the suture materials.
Non-absorbable suture material, traditionally polypropyl-
Saws ene, is used for securing the laryngeal cartilages during
arytenoid lateralization surgery. Polypropylene is the least
Power saws remove the physical effort of cutting through thrombogenic suture material and is the material of choice
bone and are essential because of the control and accu-
for vascular surgery. Monofilament nylon with a swaged-on
racy of cut they afford. The blades are available in various reverse-cutting needle is preferred for skin sutures, inclu-
sizes and move back and forth (reciprocating) in an arc of
ding those apposing cartilage during closure of aural surgi-
5 or 6 degrees parallel to (sagittal) or at a right angle to cal procedures. Tying secure knots is an essential surgical
(oscillating) the drive shaft (Figure 1.12). The cutting teeth
skill, which may be particularly challenging within a deep
move only a small distance on the bone and adjacent soft thoracic cavity with the added distraction of the heart and
tissues are usually unaffected. The saw, blades and power
lung movements.
cable can be dismantled and sterilized. The heat produced An absorbable suture material is preferred for wound
by friction may cause heat necrosis of the bone and
closure in the oral cavity and oropharynx so that sedation
this is minimized by cooling the blade with sterile saline or anaesthesia for suture removal can be avoided.
during use. Sagittal and oscillating saws are used for
Chromic catgut persists in the oral cavity for approxi-
dorsal rhinotomies, mandibulectomies, maxillectomies and mately 4–7 days, which is considered to be ideal in
zygoma surgeries. It is mandatory to use a sagittal or oscil-
humans. However, a longer-lasting synthetic material is
lating saw for a median sternotomy to divide the sternebrae preferred in dogs and cats to avoid early wound break-
accurately in the midline. Dedicated sterno tomy saws are
down. Polyglactin 910 and polyglycolic acid are good for
available, which have a protective underplate to reduce the procedures in which healing is relatively rapid, but they
risk of the blade inadvertently lacerating adjacent struc- may elicit an inflammatory reaction in oral tissue, due to
tures upon entry into the chest. Piezoelectric surgery uti- their multifilament nature. Synthetic monofilament sutures
lizes tips that vibrate (distances range from 60 to 200 µm) induce the least foreign body reaction in oral tissues.
when precisely cutting through hard tissue, whilst leaving Poliglecaprone 25 (1 metric (5/0 USP), 1.5 metric (4/0 USP)
soft tissue untouched by the process (Reiter, 2013).
or 2 metric (3/0 USP), depending on the size of the animal
and the type of procedure being performed) has become a
very popular suture material and may persist in the oral
cavity for approximately 3–5 weeks. Polydioxanone is used
where prolonged suture strength is required (e.g. palate
surgery) and may persist in the oral cavity for 6–8 weeks
(LaBagnara, 1995). Square or surgeon’s knots should be
followed by at least three more throws to ensure knot
security in the oral cavity (Reiter, 2013).

Surgical needles
Swaged needles glide smoothly and efficiently through
tissue and are considered mandatory for atraumatic soft
tissue surgery. Needles with varying curvatures (e.g. to
(a) (b) ½ circle) are most versatile and commonly used. Taper-
point needles are non-cutting round needles, which are
The sternebrae of a large dog may be cut using (a) an
1.12 oscillating saw or (b) a sagittal saw. used for viscera, muscle, fat and cardiovascular tissues.
They are also preferred for wound closure in the oral cavity
and oropharynx, thus reducing trauma to already inflamed
or friable tissues. Certain cardiovascular procedures
Surgical biomaterials require the use of suture material with a needle swaged on
Suture materials to both ends. Small, swaged-on circle, reverse-cutting
needles may cause minimal tissue drag, but have the
Many of the synthetic absorbable suture materials are potential to tear through delicate or inflamed tissue.
appropriate for use in soft tissue surgery. Poliglecaprone
25, polyglactin 910 and polyglycolic acid lose a significant
portion of their tensile strength relatively rapidly (1–2 Surgical staplers
weeks) and are suitable for subcutaneous tissues and Mechanical staplers are an efficient alternative to manual
muscle. The oesophagus, similar to the rest of the gastro- suturing for a variety of intrathoracic procedures. When
intestinal tract, heals rapidly, and use of a monofilament applied correctly, surgical staplers provide consistent and

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