INTRODUCTION:
Fibrin sealant
has been used for many years and has a wide range of clinical applications for
suture support, tissue adhesion, and hemostasis. Fibrin sealant imitates the
final phase of the blood coagulation process. Fibrinogen is converted to fibrin
on a tissue surface by the action of thrombin, which is then cross-linked by
factor XIIIa, creating a mechanically stable fibrin network. This fibrin
network is thought to reduce the amount of postoperative bleeding by sealing
capillary vessels and enabling raw operative surfaces of cartilage graft to
adhere. The potential advantages of the use of such substances include
prevention of hematoma, reduction in surgical time, reduction in flap edema,
and shorter recovery time andexcellent healing. The physiologic mechanism that
creates fibrin sealant was first described by Morawitz in 1905.
We
have reviewed the world literature to find out if any study in micro-ear surgery
is done but could not find any confirmed study. Ours is the first pilat study to know the efficacy of evicel
sealant in reconstructive tympanoplasty.
Fibrin glue was originally described in 1970 and is formed by polymerizing
fibrinogen with thrombin and calcium.2 It was originally prepared using donor
plasma; however, because of the low concentration of fibrinogen in plasma, the
stability and quality of the fibrin glue were low.3 Commercially pretreated
fibrin sealant products were developed to increase the efficacy of forming a
stable clot.These products are heat treated, which greatly reduces the risk of
disease transmission. The fibrin sealant and delivery system are easy to store
and rapid to construct, and, therefore, have enjoyed some use in reconstructive tympanoplasty and cosmetic
surgery.
Fibrin sealant
(human) (Evicel; Johnson & Johnson– Wound Management, Somerville, New
Jersey) is a plasma cryoprecipitate-based sealant that consists of 2
components: (1) biological active component–2 (BAC2), also called human
clottable protein, which consists predominantly of fibrinogen and (2) thrombin.
BAC2, a concentrated solution of clottable plasma proteins, consists mainly of
fibrinogen and other proteins. The thrombin solution contains highly purified human
thrombin and calcium chloride for activation of clotting of the final combined
product. Thrombin is a highly specific protease that transforms the fibrinogen
contained in BAC2 into fibrin. Fibrin sealant (human) (Evicel; Johnson &
Johnson– Wound Management, Somerville, New Jersey) is a plasma
cryoprecipitate-based sealant that consists of 2 components: (1) biological
active component–2 (BAC2), also called human clottable protein, which consists
predominantly of fibrinogen and (2) thrombin. BAC2, a concentrated solution of
clottable plasma proteins, consists mainly of fibrinogen and other proteins.
The thrombin solution contains highly purified human thrombin and calcium
chloride for activation of clotting of the final combined product. Thrombin is
a highly specific protease that transforms the fibrinogen contained in BAC2
into fibrin. It is indicated as supportive treatment in patients undergoing
reconstructive tympanoplasty.
ABOUT EVICEL SEALANT:
u Thaws within 10 minutes at 37°C (and
must not be kept at this temperature for longer than 10 minutes); within 1 hour
at 20°C to 25°C (room temperature); or within 1 day at 2°C to 8°C
(refrigerator). Once thawed, EVICEL® must not be refrozen. Once at room
temperature, EVICEL® must not be refrigerated
u All-Human formulation –
EVICEL® Fibrin Sealant does not contain aprotinin or bovine derivatives
and does not expose patients to the risks associated with aprotinin264
u Multiple, clog-resistant tip options
– Standard 6 cm tip or 35 cm Rigid or 45 cm Flexible tip.
IMPORTANT RISK INFORMATION:
u Do not inject directly into the
circulatory system. Intravascular application of EVICEL® may result in
life-threatening thromboembolic events.
u Do not use in individuals known to
have anaphylactic or severe systemic reaction to human blood products.
u Do not use for the treatment of
severe or brisk arterial bleeding
Most common adverse events reported
in clinical trials (=5%) are bradycardia,
nausea, hypokalemia, insomnia,
hypotension, pyrexia, graft infection, vascular
graft occlusion, peripheral edema,
and constipation.
Evicel is
provided as a single-use human surgical sealant kit consisting of 2 packages,
the first containing 1 vial each of frozen sterile solutions of BAC2 (Biological
Active Componant 2) and thrombin and the second containing the sterile
application device. It is the only totally human protein–derived, bovine-free
fibrin sealant commercially available in the United States. The unit cost for 2
mL of fibrin sealant plus the applicator is $200(1Rs.12000). The vials are
stored in a freezer; when removed and thawed, they are stable for 24 hours. The
vials are readily thawed in 5 minutes without the use of a rapid-warming
device. After the BAC2 and thrombin solutions are thawed, they are drawn into a
unique trilumenal (2 syringe lumens and 1 air lumen for spraying) catheter
application device. As the plungers are depressed simultaneously, the solutions
are mixed by the applicator and sprayed into the operative site.
The applicator
gently sprays the fibrin sealant into the operative wound as a thin layer and,
therefore, allows a relatively small volume (1 mL) of sealant to be delivered
evenly. The solutions mix as they exit the catheter during administration, are
applied topically by dripping and once applied are transparent. The
reconstituted preparation mimics the final steps in physiologic coagulation.
Fibrinogen is converted to fibrin on the wound surface in presence of calcium
ions by the actions of thrombin and factor XIII, all derived from human plasma.
A stable cross-linked fibrin clot is formed over the neotympanum.
Recently we have
done 50 cases of type one tympanoplasties with inlay composite cartilage graft.
After the surgical procedure is over the evicel (1.5 ml) solution is applied
over the surface of the graft material by the evicel triluminal applicator and
it was kept for over 3 to 5 minutes to form a solid layer over the neotympanum.
So far 50 casers being treated with this technique and found to be excellent in
graft take up (98%) and without medialization or lateralization . No
complications encountered during evicel application. Graft take was 98% post operatively.
More study will be required for its efficacy in reconstructive tympanoplasty.We
plan to do more cases with varied middle ear pathology like ossiculoplasty, ossiousplasty
( Bony defect reconstruction as attic, defect, PSQ defect and canal wall defect.
Its effect on graft fixing is very encouraging which inspired us to take up
this study in middle ear reconstruction.
RESULTS:
u The results were evaluated in the
form of graft uptake, hearing outcome and complications.
u Healed neo-tympanic membrane, which
moves on seigelization was taken as successful graft take-up, while any
residual perforations or retraction of neo-tympanum were taken as failures.
u Postoperative and preoperative
pure-tone audiograms were compared. Hearing gain and mean residual gaps were
evaluated in speech frequencies of 500, 1000, and 2000 Hz.
ADVANTAGES:
u Reduction in the graft displacement
as a cause of failure
u Ease of use. Comes with the
application device and is easy to set up and ready to use.
u Works on all types of grafts so your
primary surgery does not need any alterations.
u Application takes just an extra few
minutes at the end of the surgery.
DRAWBACKS
u Need for a longer study with more
number of cases to prove its statistical significance
u Affordability and Availability of
the fibrin sealant.
TO SUMMURIZE:
u The pilot study shows promising
results.
u Encourage ENT surgeons to use a
fibrin sealant and publish your results and feedback regarding the same.
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