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The effects of puncture of fresh cadaver dura with 20-, 22-, 26- and 29-gauge needles were observed. A 'tin-lid' phenomenon, manifested with all needle sizes, was capable of sealing the resultant hole. The larger the needle, the larger the hole, while rotation of the needle bevel 90 degrees to the fibres altered the shape of the hole. Holes made in thicker parts of the dura tended to retract more rapidly than those in thinner areas.
Dittmann et al. (Mon,) studied this question.