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Duraplasty: Our Current Experience - 3 go / dental&marketing

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<strong>Duraplasty</strong> Surg Neurol<br />

2004;61:55–9<br />

ever possible, but when it is not possible, we prefer<br />

to use homolo<strong>go</strong>us implants.<br />

Despite the theoretical advantages of no risk of<br />

infection of the synthetic materials [2], most of these<br />

have been rejected because of local tissue reactions,<br />

excessive scar formation, meningitic symptoms, or<br />

hemorrhage risk [1,2,13,19,31,33,34,35,41,50].<br />

For many years lyophilized homolo<strong>go</strong>us dura mater<br />

sterilized by � rays (Lyodura) has been widely<br />

used because it is easy to handle and widely available<br />

[9,10,24,39,50]. Unfortunately, the current sterilization<br />

methods do not guarantee them free from<br />

risk of latent virus infections [16,42,49], and some<br />

cases of probable Creutzfeldt-Jacob disease (CJD)<br />

after homolo<strong>go</strong>us dura mater implant have been<br />

reported [42]. However, these cases remain circumstantial<br />

because there are not other cases in patients<br />

treated with the same lot of dura. Moreover,<br />

the use of cadaveric dural grafts has not been prohibited<br />

by World Health Organization [50].<br />

In our institution we have used Tutoplast dura as<br />

dural substitution for many years because it is a<br />

material widely available, waterproof, with tensile<br />

strength, easily suturable, biocompatible, and relatively<br />

inexpensive.<br />

Despite achieving <strong>go</strong>od results in our patients<br />

with Tutoplast Dura implant (no complication in<br />

more than 99% of the cases), we think that the risk<br />

of transmission of prionic disease, even if minimal<br />

and never proven, should proscribe its use. Until<br />

now, iatrogenic transmission of CJD occurred by<br />

corneal implantation, intracranial electrodes, human<br />

growth hormone extracts from cadaveric pituitary<br />

gland, and cadaveric dura mater graft [42]. In<br />

experimental transmission, the CJD agent has been<br />

found in brain, spinal cord, lung, liver, and kidney<br />

[7,27,42]. In the last several years in our institute we<br />

use Tutoplast pericardium that is a homolo<strong>go</strong>us<br />

material with the same advantages of the Tutoplast<br />

dura but likely safer than homolo<strong>go</strong>us dura mater.<br />

In our series, we found postoperative complications<br />

in 4 (1.7%) of the 250 patients subjected to<br />

implant of dural homolo<strong>go</strong>us substitutes. However,<br />

the relationship between dural patch and the complications<br />

in these four cases remains debatable.<br />

In patients No. 1 and No. 2 a postoperative meningeal<br />

syndrome was documented by clinical picture<br />

and laboratory test.<br />

In patient No. 1 meningeal reaction was aseptic,<br />

and the operation was performed in posterior cranial<br />

fossa. In this case we can hypothesize either an<br />

inflammatory reaction of the host against the implanted<br />

material or a spread of blood breakdown<br />

products into subarachnoidal spaces, causing an<br />

irritative meningeal syndrome. The latter hypothe-<br />

57<br />

sis is sustained by the fact that aseptic meningitis<br />

syndrome has been described as a common complication<br />

of posterior cranial fossa surgery<br />

[12,15,17].<br />

In the remaining patients there was an infection,<br />

and in those cases it can be hypothesized as both<br />

an infection arising from dural plasty and a contamination<br />

unrelated to the dural graft.<br />

The latter hypothesis is supported by the fact<br />

that the method of preparation of Tutoplast and<br />

�-irradiation ensures the sterility of the grafts [10]<br />

and because there were no other cases of infection<br />

in patients of our series treated with the same lot of<br />

dura.<br />

In patient No. 2 it could be reasonably assumed<br />

that the development of infection was because of a<br />

contamination from extracranial bacteria. This is<br />

supported by the presence of a connection between<br />

the endocranium and the airways.<br />

In patients No. 3 and No. 4 we found at the previous<br />

surgical wound an SC and submuscular purulent<br />

collection positive for St. Aureus and St. Epidemidis,<br />

respectively.<br />

At reintervention, Patient No. 3 presented SC and<br />

submuscular purulent collection, disappearance of<br />

the dural patch, and no signs of infection on the<br />

cerebellar surface. From these aspects we can presume<br />

that the infection started in the superficial<br />

tissues and destroyed the dural patch.<br />

In Patient No. 4 there was an extradural purulent<br />

collection, complete dural patch resorption, and<br />

signs of inflammatory reaction on cerebellar surface.<br />

Also, in this case we can suppose that infection<br />

is originated extradurally because the cultures<br />

of the purulent SC and submuscular collection were<br />

positive for an infective agent commonly present in<br />

the skin and easily destroyed by �-sterilization.<br />

Keener [21] stated that only fibroblast originating<br />

from soft tissues (muscle, fascia, SC space) regenerate<br />

the dura, and when dural defect is adjacent to<br />

bone, dural healing is inadequate.<br />

In our cases No. 3 and No. 4 dural patch was<br />

adjacent to soft tissue, but it is likely that the septic<br />

contamination and consequent inflammatory reaction<br />

destroyed the dural graft more rapidly than the<br />

time needed for fibrous infiltration and dural regeneration<br />

processes.<br />

Adherence to the cortex were not observed in the<br />

4 patients who underwent an early reoperation or in<br />

the 9 patients reoperated on tardily. Macroscopically,<br />

dural patch was preserved and appeared as<br />

host dura. In 1 patient there was granulation tissue<br />

above the graft when this was exposed in a small<br />

area without bone. In 3 patients who had post-

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