Anesthesia (13)

Abstract

An in vitro study of dural lesions produced by 25‐gauge Quincke and Whitacre needles evaluated by scanning electron microscopy. (Hospital de Mostoles, Madrid Spain) Reg Anesth Pain Med 2000;25:393–402.This study evaluated the dural lesions produced by Whitacre and Quincke spinal needles in the external and internal surface of the dura mater of the lower spine area in an attempt to gain more insight into the pathophysiology of postdural puncture headaches (PDPH). The T11‐L4 dural membranes from 5 fresh (immediately after extraction of organs for transplantation) male patients declared brain dead, ages 23, 46, 48, 55, and 60, were excised by anterior laminectomy. Morphologic orientation of the membrane and normal pH were maintained; 100 punctures at 90‐degree angles were done with a new needle each time, 50 with 25‐gauge Whitacre and 50 with 25‐gauge Quincke needles. Half of the punctures with the Quincke needles were done with the bevel in the parallel direction to the axis of the spinal cord, and the rest with the bevel perpendicular to it. Fixation in solutions of 2.5% glutaraldehyde phosphate buffer, followed by dehydration with acetone, was done 15 min after the punctures. The acetone was removed and the specimens were metallized with carbon followed by gold and inspected under a scanning electron microscope. When the area of the dural lesions found in the external and internal surfaces produced by the 2 types of needles was compared, no significant differences were found. The percentage of lesion closing area with the Quincke needles was 88.3% and 82.7% in the external and internal surfaces, respectively. With the Whitacre needles, the percentage of closing was 86.8% and 84.8% in the epidural and arachnoid surfaces, respectively. There were differences noted in the morphology of the lesions. The Whitacre needles produced coarse lesions with significant destruction in the dura's fibers while the Quincke needles produced a “U”‐shaped lesion (flap) that mimics the opened lid of a tin can, regardless of the tip's direction. Conclude that the needles produced lesions in the dura with different morphology and characteristics. Lesions with the Quincke needles resulted in a clean‐cut opening in the dural membrane while the Whitacre needle produced a more traumatic opening with tearing and severe disruption of the collagen fibers. The lower incidence of PDPH seen in the Whitacre needles may be explained, in part, by the inflammatory reaction produced by the tearing of the collagen fibers after dural penetration. The inflammatory reaction may result in a significant edema, which may act as a plug limiting the leakage of the cerebrospinal fluid. Comment by Andrew D. Rosenberg, MD.This is an interesting article that explains why a patient will develop a postdural puncture headache (PDPH) after receiving a spinal with a Quincke needle and not after a Whitacre‐type needle. The explanation is based more upon an inflammatory reaction than the direction of the needle cut. The Quincke needle appears to make a sharp cut while the Whitacre needle induced an inflammatory response including edema, which could block off the dura from leaking. It is very interesting that the response seen after the Whitacre needle was utilized occurred as quickly as it did. The article introduces the question as to whether a Quincke needle or a Whitacre needle is associated with more trauma to the dura, and which is better for decreasing the incidence of PDPD.