Transcript PowerPoint Presentation - THE INFLUENCE OF CRANIECTOMY …

RELATIONSHIP BETWEEN CRANIAL
DEFECT AND PHYSIOLOGY OF CEREBROSPINAL
FLUID: An experimental study in
rabbits
Dr. Ersin Erdogan
Department of Neurosurgery Gulhane
Military Medical School
Ankara, TURKEY
Objective
The aim of this study is to determine the effect of
craniectomy on the flow kinetics of CSF, in vivo.
Introduction
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Decompressive craniectomy performed;
to reduce the increased intracranial pressure due to
different etiological factors,
may cause clinical findings which called “Sinking skin flap
or trephined syndrome”
Mizumaki Y, Oka N, Itoh K, Endo S. A case of traumatic hydrocephalus after large craniectomy for
acute subdural hematoma. No Shinkei Geka 2003;31:201-206
Introduction
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When cranioplasty had been applied to the cases of
craniectomy, the objective and subjective improvements in
clinical, cognitive and physiological findings were
observed.
Erdogan E, Duz B, Kocaoglu M, Izci Y, Sirin S, Timurkaynak E. “The effect of cranioplasty on
cerebral hemodynamics: evaluation with transcranial Doppler sonography.” Neurol India. 2003
Dec;51(4):479-81.
Material and Methods
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The experiments were conducted using eleven
male New Zealand white rabbits weighing
between 1500 and 1800 g
The rabbits were anesthetized with a combination
of ketamine and xylazine
cisternography with 300±50 microcurie/0.1 cc Tc-99mdiethylenetriamine pentaacetic acid (Tc-99m-DTPA)
injected into the 4th ventricle of the rabbits via insulin
injector.
Kusumi and Plouffe 1979
Scanning
The rabbit was positioned laterally, with the
lateral cranial surface facing the detector of
the gamma camera
(Rabbit # 3) The
control cisternography of the rabbit performed
at the 3rd month postoperatively. The reframed 1 hour follow-up image.
Scanning
Dynamic data acquisition in every
minute for a period of one hour was
performed
 Data
were generated over the
subsequent 60-minute at 60 second per
frame in a dynamic mode after regions
of interest were placed around the
injection site.
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Scanning
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The computer-generated time activity curve
for region of interest by using commercially
available software (Entegra). Using data
clearance half time (t 1/2) for each region of
interest was generated in seconds using an
exponential fit.
The t 1/2 values of pharmaceutical agent for
each study were calculated with the same
method and the results were recorded.
Surgery
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After the preoperative cisternography, all
rabbits were anesthetized The scalp was
shaved, prepped with Betadine, and a midline
scalp incision was made.
The periosteum was reflected laterally and a
craniectomy was performed with microscopic
magnification. The dura was exposed
overlying right cerebral hemisphere and the
scalp was then closed.
The mean width of cranial defect was 1/3 of
hemicranium.
Statistical analysis
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Differences in DTPA clearance t 1/2
before and after craniectomy were
compared using the Wilcoxon Signed
Ranks test.
Results
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Four rabbits died in the 7th day of the
experiment and a total of 5 rabbits died at the
end of 3rd month and they were excluded from
this study. The t 1/2 values and median (mean;
minimum-maximum) t 1/2 values obtained
preoperatively, 24th hour, 7th day and 3rd
month postoperatively are summarized in
Table.
Table: The T1/2 values of the rabbits in preoperative
and postoperative period.
Pre operati ve
Rabbi t
24th h ou r
7th day
3rd month
postoperati ve
postoperati ve
postoperati ve
1
1589
1361
1728
3303
2
1838
2322
2847
2194
3
2795
2861
-
-
4
2357
3255
-
-
5
2237
1634
3110
1339
6
1857
3595
-
-
7
1522
1726
2000
1180
8
1932
2100
1838
-
9
1343
1768
2480
2477
10
2663
2261
-
-
11
2148
1901
2030
1731
Statistically significant difference was not found between these results
according to Wilcoxon Signed Ranks test.
The exponential fit applied-time/activity curve obtained
from the region of interest drawn on the site of injection.
Conclusion
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There is no doubt that the physiology of CSF
is being influenced by cranial defect.
The most important evidence of this situation
is variations of CSF pressure.
This pathophysiological change of CSF due
to cranial defect is not clear, but it could be
related to overproduction or decreased
absorption of CSF that may increase
pressure.
Conclusion
Our study is the first experimental study,
which investigated the physiology of
CSF kinetics via cisternography by
protecting in vivo conditions.
 Certainly, we stated that cranial defect
do not cause statistically significant
difference on the CSF kinetics.
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