Background and Objectives Tissue cores, implanted into the subarachnoid space during subarachnoid injections, can develop into intraspinal lumbar epidermoid tumors. The availability of smaller needles has made spinal anesthesia more popular. Therefore, this prospective, randomized, blinded study was undertaken to determine whether tissue coring occurs with two of the currently used 25-gauge spinal needles.

Methods Fifteen 25-gauge Quincke and seventeen 25-gauge Whitacre spinal needles, in which cerebrospinal fluid (CSF) was not identified and the local anesthetic solution not injected, were obtained from adult male patients undergoing spinal anesthesia. The needles were then evaluated by a pathologist following randomization with similar sterile, unused spinal needles. Twenty additional needles, ten of each type, in which CSF was identified and through which local anesthetic was injected, were also randomized with similar sterile, unused spinal needles and examined.

Results Tissue cores were identified in 12 of the 15 Quincke and 7 of the 17 Whitacre spinal needles in which CSF was not identified (P < .05). Of the 20 needles in which CSF was identified and local anesthetic injected, no tissue cores were identified in the 10 Whitacre needles and only one small tissue core was identified in the 10 Quincke needles. All the tissue cores were identified as fat tissue.

Conclusions The 25-gauge Quincke and 25-gauge Whitacre spinal needles currently used in anesthesia can produce tissue coring.