BACKGROUND AND OBJECTIVES: Pain during spinal puncture is a warning that needle tip has touched a nervous structure. If patients refer pain during puncture, it is mandatory to interrupt the technique. Anesthetic solution should not be injected to prevent potential nervous root or spinal cord injury. Needle should be drawn back and have its direction changed before a new advance is attempted. Pain complain is totally impossible if patients are asleep under the influence of general anesthesia and that is why blockade with conscious patients is advisable. Pain is only referred when needle or catheter tip bypass the medium sagital plane to reach the antero-lateral epidural compartment, thus being able to touch nervous rootlets close to intervertebral foramina. Except for studies on skin, subcutaneous tissue and interspinous ligament innervation, this study aimed at reviewing the innervation of some spinal canal structures, namely, ligamentum flavum, posterior longitudinal ligament, dura-mater and intervertebral disk. CONTENTS: Studies on spinal canal innervation are presented in this literature review, aiming at understanding pain during spinal puncture. CONCLUSIONS: Ligamentum flavum is not innervated, thus explaining lack of pain during puncture. Other pains during puncture may be attributed to Luschka's nerve, which innervates posterior longitudinal ligament and dural ventral portion.
ANESTHETIC TECHNIQUES; ANESTHETIC TECHNIQUES; ANESTHETIC TECHNIQUES
