Title: RELATIONSHIP BETWEEN CRANIAL DEFECT AND PHYSIOLOGY OF CEREBROSPINAL FLUID: An experimental study in
1RELATIONSHIP BETWEEN CRANIALDEFECT AND
PHYSIOLOGY OF CEREBROSPINAL FLUID An
experimental study inrabbits
- Dr. Ersin Erdogan
- Department of Neurosurgery Gulhane
- Military Medical School
- Ankara, TURKEY
2Objective
- The aim of this study is to determine the effect
of craniectomy on the flow kinetics of CSF, in
vivo.
3Introduction
- 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
200331201-206
4Introduction
- 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 Dec51(4)479-81.
5Material and Methods
- 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
6cisternography with 30050 microcurie/0.1 cc
Tc-99m-diethylenetriamine pentaacetic acid
(Tc-99m-DTPA) injected into the 4th ventricle of
the rabbits via insulin injector.
Kusumi and
Plouffe 1979
7Scanning
The rabbit was positioned laterally, with the
lateral cranial surface facing the detector of
the gamma camera
8(Rabbit 3) The control cisternography of the
rabbit performed at the 3rd month
postoperatively. The reframed 1 hour follow-up
image.
9Scanning
- 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.
10Scanning
- 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.
11Surgery
- 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.
12Statistical analysis
- Differences in DTPA clearance t 1/2 before and
after craniectomy were compared using the
Wilcoxon Signed Ranks test.
13Results
- 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.
14Statistically significant difference was not
found between these results according to Wilcoxon
Signed Ranks test.
15The exponential fit applied-time/activity curve
obtained from the region of interest drawn on
the site of injection.
16Conclusion
- 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.
17Conclusion
- 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.
18(No Transcript)