Objective  To compare effect of isobaric lumbar anesthesia at low blocking planar and saddle anesthesia in anorectal surgery.

  Methods  Totally 80 patients with anorectal surgery were randomly divided into saddle anesthesia group (n=40) and lumbar anesthesia at low blocking planar group (n=40). In the saddle anesthesia group, 5.0 mg bupivacaine combined with 0.3 mL 10% glucose was injected into the tail slowly under the normal sitting position, while 5.0 mg 0.5% isobaric bupivacaine was injected into the tail slowly under the left lying position in the low plane lumbar anesthesia group, and anesthesia plane was controlled at the level of L_4~5. The operation time of anesthesia, onset time of anesthesia, duration of analgesia, autonomic micturition recovery time, lower limb movement blocking and urine retention were compared between the two groups.

  Results  The patients in both groups completed operation successfully. In the lumbar anesthesia at low blocking planar group, the operation time of anesthesia, duration of analgesia and autonomic micturition recovery time were significantly shorter than those in saddle anesthesia group (P < 0.05), and the incidence rate of urinary retention was significantly lower than that in saddle anesthesia group (P < 0.05).

  Conclusion  Compared with saddle anesthesia, isobaric lumbar anesthesia at low blocking planar is easy to operate in clinical practice, which has advantages of better anesthetic effect, less influence on lower limb movement function and circulation, and lower incidence rate of postoperative urinary retention.