Biomedical Engineering Reference
In-Depth Information
can be either soft latex (Penrose) or a more rigid tube made
of polypropylene, Silastic, or red rubber (
Miller, 2003
). It is
difficult to maintain functional drains as nonhuman
primates like to investigate and remove foreign material
they can grasp. Active drains need to be connected to
a source of negative pressure (syringe, suction device) and
thus are difficult to use in nonhuman primates.
Subcutis (the hypodermis) is composed of a more
superficial adipose layer resting on the deeper panniculus
muscle. While undermining the skin, staying below the
panniculus muscle layer will preserve the subdermal plexus
to secure blood circulation. Blunt separation while avoiding
larger vessels is advised. For closure, synthetic, absorbable
materials with low tissue reactivity should be used.
Hemostasis using ligation or electrocautery and elimination
of dead space contributes to progressive healing. When
closing muscles after implantation surgery, the muscle and
muscle fascia should be used to create as much separation
as possible between the implant and the skin before the
latter is closed. For fascia closure, using synthetic, mono-
filament, nonabsorbable material where the strength is
critical is advised. Synthetic, absorbable material may be
used where the strength is not critical. For muscle closure,
using synthetic absorbable or nonabsorbable material is
recommended.
Skull
The skull needs to be treated with respect for normal bone
architecture! First, gently mobilize the skin and muscles
and avoid traumatizing the pericranium (periosteum over
cranial bones) in order to preserve bone nourishment during
healing. The authors discourage a commonly practiced
procedure of scraping off the pericranium for better
adherence of bone cement. If bone thinning is needed, the
appropriate drill and drill bits are necessary. In spite of the
availability of new technologies (e.g. nitrogen-powered
drills,
Figure 14.3
C,D),
Skeletal Muscle
For surgical manipulation of the skeletal muscle, a blunt
separation to minimize bleeding and post-traumatic
swelling is recommended. Separation along, rather than
across, the muscle fibers reduces trauma, secondary
hemorrhage, and swelling. Fascia is a thin, strong,
connective membrane located on the outside of the muscle
which provides strength when included in muscle closure.
the authors recommend using
(A)
(B)
(C)
(D)
FIGURE 14.3
Drills.
(A) Manual drills. (B) Electric drill. (C,D) Nitrogen-powered drill.
