Biomedical Engineering Reference
In-Depth Information
capsule and superficial parenchyma closure with 3-0 or 4-0
synthetic absorbable suture using simple continuous pattern.
often inspect the site of surgery, particularly when
prompted by local sensation such as pain or itchiness, or
just due to simple boredom. The authors recommend
building a database initiated during the quarantine during
which carefully observed animals may display propensities
towards future behavioral patterns such as pulling hair,
playing with body parts, excessive scratching, and self-
biting. These patterns may provide insights into future
postoperative behaviors. The initial touching and picking
may escalate to pulling or jerking, and be directed towards
skin sutures, bandages, percutaneous drains, or implanted
devices. A piece of gauze and adhesive tape applied to the
limb where an intravenous catheter had been placed during
surgery routinely becomes an object of attention and
vigorous attempts to remove it sometimes as soon as 10
Brain
Even very gentle manipulations can be traumatic and lead
to life-threatening postsurgical edema. Vigorous intra-
operative positive pressure hyperventilation reduces brain
swelling by lowering blood CO
2
. Intra- and postoperative
therapies include mannitol,
furosemide, and systemic
corticosteroids.
Duration of Surgery
Quality should never be compromised by speed although
shorter surgeries are generally safer. Longer surgery and
thus longer anesthesia contributes to combinations of
hypotension, hypothermia, hypoglycemia, hypoxia, respi-
ratory and metabolic acidosis, respiratory and central
nervous system depression, and cardiac arrhythmia, each of
which is capable of creating problems ranging from pro-
longed recovery to death. Developing a clear plan of action,
discussing the case with the research team, practicing select
parts of the procedure (e.g. suturing techniques) on
carcasses, and staying focused may reduce the surgery time
quite dramatically. It is recommended to manage the timing
by requesting a written surgical plan inclusive of time
estimates for each section from the research team.
30
minutes after the return to the home cage. Nonhuman
primates are very reluctant to maintain wound dressings of
any kind, and protective jackets are often necessary if
wounds cannot be closed subcuticularly or if surgical drains
must be used. Wounds on hands, feet, and tails are espe-
cially difficult to protect in nonhuman primates and may
require use of both jackets and tranquilizers or sedatives.
e
Sutures, Needles, and Suturing Patterns
Animal subjects are more likely than humans to chew, lick,
and otherwise contaminate sutured wounds. The authors
recommend appropriately sized synthetic, absorbable
sutures for buried applications such as polyglactin 910
(Vicryl
by Ethicon or Polysorb
by USSC), polyglycolic
acid (Dexon
by Davis and Geck), or polydioxanone (PDS
II
by Ethicon). The use of silk sutures in animals is often
associated with excessive tissue reaction, increased
susceptibility to infection (
Turner and McIlwraith, 1982b
),
and wicking (due to braided construction), and is not rec-
ommended unless research need outweighs the risks of
use. Gut or chromic gut are absorbed by inflammation and
lose strength more quickly than synthetic absorbable
sutures and are not a good choice for use in nonhuman
primates. For skin closure it is recommended to use fine,
absorbable sutures in a subcuticular pattern applied using
a small, reverse cutting needle, such as an FS-2. For the
skin the authors recommend synthetic, nonabsorbable,
monofilament sutures, such as nylon (Ethilon
by Ethicon,
Monosof
by USSC, or Surgilon
by Davis and Geck) or
polypropylene (Prolene
by Ethicon, Surgipro
by USSC,
or Surgilene
by Davis and Geck). It is not recommended
to use stainless steel wound clips or staples in the skin of
nonhuman primates. An excellent suture pattern to use in
the skin of nonhuman primates is the cruciate mattress,
which allows easy removal and minimal tissue overgrowth.
To close using the cruciate mattress pattern, the needle is
inserted 7
Record Keeping
Surgical and anesthetic records are important documents
providing unique retrospective account of critical events
that are required by law. The surgeon must focus on the
surgery while a well-trained and experienced veterinary
technician can take accurate perioperative notes and record
important intraprocedural events observed or verbally
communicated by the researcher or the veterinarian.
Medical records are a key element of the veterinary care
program and are considered critical for documenting
animal well-being as well as tracking animal care and use at
a facility (
National Research Council, 2011a
).
Operative and Postoperative
Considerations
Wound Healing and Dressing
More appropriately termed wound repair, wound healing is
a process composed of sequential steps leading to restora-
tion of the continuity of tissue that is mediated by cyto-
kines. Basic mechanisms in wound repair are angiogenesis,
fibroplasia, epithelialization, and wound remodeling and
contraction (
Brown, 2003
). Nonhuman primates are intel-
ligent, curious, industrious, and manually gifted animals
who do not necessarily make cooperative patients. They
10 mm from the edge of the wound on the right
side and passed to the left side where it exits the skin
e
