Nerve block: perianal block

(Redirected from Perianal block)


Perineal innervation.
  • Perianal blocks have been shown to be comparable to general anesthesia for in terms of pain control in anal procedures including surgeries [1]
  • "Perianal block is a safe, feasible, reliable, and reproducible mode of anesthesia." [2]



  • Overlying infection
  • Allergy to chosen anesthetic
  • Uncooperative patient

Equipment Needed

  • 20 cc Syringe with a 27 Gauge Needle
  • Spare 18 Gauge Needle (to draw up anesthetic)
  • Local Anesthetic (e.g. Lidocaine or Bupivacaine)
  • Silk Tape
  • Pillow or Blankets
  • Packaged, Moist Towelette


  • Obtain informed consent
  • Place the patient in the prone position, placing either a pillow or blankets under their hips for comfort and ideal positioning
  • Using tape, separate the patient's buttocks from one another to better visualize the perianal area
  • Draw up anesthetic into 20 cc syringe using 18 Gauge Needle
  • Ensure that the perianal area is clean by removing debris with moist towelette
  • Peripheral to the anal sphincter, choose multiple injection sites that allow for fanning circumferentially around the anus
  • Advance 27 Gauge needle into one of these preselected areas
  • Aspirate to rule out intravascular placement prior to injecting 3 -5 mL of anesthetic
  • Continue to the other preselected areas, fanning the needle circumferentially in order to surround the anal area with local anesthetic


See Also

External Links


  1. Gerjy, R. et al. Randomized clinical trial of stapled haemorrhoidopexy performed under local perianal block versus general anaesthesia. Br J Surgy. 2008; 95(11):1344-51.
  2. Bharathi, R. et al. Evidence based switch to perianal block for ano-rectal surgeries. International Journal of Surgery. 2010; 8:29–31
  3. Nystrom, PO. et al. Local perianal block for anal surgery. Tech Coloproctol. 2004; 8(1):23-6