Læknablaðið - 15.05.1993, Blaðsíða 42

212
LÆKNABLAÐIÐ 1993; 79: 212
NÝR DOKTOR í LÆKNISFRÆÐI
ÞORVALDUR JÓNSSON
Þann 4. desember 1992 varði Þorvaldur
Jónsson læknir doktorsritgerð við háskólann í
Lundi. Ritgerðin nefnist á frummáli: »Changes
in early strength of intestinal anastomoses«.
Fer ágrip hér á eftir.
The early healing of anastomoses in the
rat small bowel was investigated. Strength
was measured as intestinal suture-holding
capacity, i.e. anastomotic breaking strength
with the sutures in place. The accumulation
of neutrophil granulocytes in the anastomosis
was quantified with a myeloperoxidase (MPO)
assay, and the content and solubility of
anastomotic collagen (hydroxyproline) were
assessed. Three days after surgery anastomotic
strength had decreased by as much as 85%,
depending on the suture technique used. The
decrease was completely abolished in animals
that were preoperatively made neutropenic
with antineutrophil serum. One day after
surgery the decrease was also fully prevented
by systemic administration of the soya bean
trypsin inhibitor (STI), a serine proteinase
inhibitor, while the effect of STl after three
days was incomplete. Systemic treatment with
the tissue inhibitor of metalloproteinsases
(TIMP), a physiological inhibitor of the
matrix metalloproteinases, had a significant
and dose-related effect on strength one
day after surgery, but no effect after three
days. The increased inflammatory reaction
caused by diathermy was not detrimental
to early anastomotic strength. A model was
developed to regulate suture tying tension',
i.e. the tension applied when the sutures
are knotted. The decrease in anastomotic
strength was proportional to the tying tension.
The size of the tissue bites also infiuenced
strength, but not to the same degree as tying
tension. Interrupted and continuous sutures
Key words: Anastomosis, animal studies, collagen,
hydroxyproline, myeloperoxidase, neutrophil leukocyte,
proteinases, proteinase inhibitors, surgical technique,
wound healing.
had similar effect on strength if the tying
tension was taken into account. Except for the
neutropenic state, the changes in anastomotic
strength did not correlate with the anastomotic
MPO activity, nor were they accompanied by
comparable changes in anastomotic collagen
content or solubility. These findings suggest
that the pathophysiological mechanisms
responsible for the decrease in the early
strength of intestinal anastomoses are
neutrophil-dependent, and to a substantial
degree mediated by serine proteinases, while
the role of the matrix metallproteinases
seems limited. It is speculated that tightly
tied sutures may upset the balance between
neutrophil proteinases and their inhibitors in
the intestinal wound.