Application of ALCOCK Tube Ultrasound-guided Internal Pudendal Nerve Block in Postoperative Anal Analgesia


ALCOCK tube, Analgesia, Anus surgery, Nerve block


How to Cite

Qiu, R., Bi, Z., Li, X., Zheng, X., Zheng, B., & Chen, P. (2023). Application of ALCOCK Tube Ultrasound-guided Internal Pudendal Nerve Block in Postoperative Anal Analgesia. Iranian Red Crescent Medical Journal, 25(8).


Background: While surgery is the most effective treatment for anorectal diseases, traditional anesthesia methods are increasingly regarded not suitable for the clinical needs of anorectal patients. Although pudendal nerve block can play a good analgesic role in the anal region, the traditional pudendal nerve block is performed under blind probing, which is inaccurate in positioning, has poor anesthesia effect, and causes many complications.

Objectives: At present, ultrasound-guided pudendal nerve block for analgesia has emerged in clinical practice. Therefore, the present study aimed to investigate the analgesic effect of ALCOCK tube ultrasound-guided internal pudendal nerve block in anal surgery.

Methods: A prospective study was conducted. A total of 134 patients who underwent anal surgery in Hangzhou Lin'an District First People's Hospital from May, 2021 to July, 2022 were divided into three categories according to mixed hemorrhoids, anal fistula, and anal fissure and randomly divided into control and experimental groups. The two groups were treated with corresponding surgical treatment, and the experimental group was treated with bilateral pudendal nerve block under the guidance of ALCOCK tube ultrasound at the end of the operation. The operation time, blood loss, initial postoperative pain time, and visual analogue scale, postoperative pain score at each time point, incidence of complications, and patient satisfaction were recorded and analyzed.

Results: The operation time of the experimental group was significantly longer than that of the control group, the bleeding volume of anal fistula in the experimental group was more than the control group, the first pain time of anal fistula in the experimental group was higher than that of the control group. The first pain score of anal fistula in the experimental group was lower than that of the control group. Follow-up showed that the pain scores of anal fistula and anal fissure groups were inconsistent 48 h after surgery. The total incidence of adverse reactions was lower, and the patient satisfaction was higher in the experimental group than in the control group.

Conclusion: The application of internal pudendal nerve block under the guidance of ALCOCK tube ultrasound in anal surgery has a good analgesic effect and high patient satisfaction, which is worthy of promotion.


Kelley K, Schulman C, Lu K, Tsikitis V. Benign anal disease: implementation of an educational program across specialties. J Surg Res. 2019;243:249-54. doi: 10.1016/j.jss.2019.05.045. [PubMed: 31252348].

Schwandner O. Quality indicators in the treatment of anal fistulas. Der Chirurg. 2019;90:270-8. doi: 10.1007/s00104-019-0794-7. [PubMed: 30683947].

Lightner A, Click B, Yamamoto T, Spinelli A, Kotze P. Management of isolated anal strictures in crohn's disease. Dis Colon Rectum. 2020;63(12):1639-47. doi: 10.1097/DCR.0000000000001834. [PubMed: 33149025].

Kumar A, Sinha N, Bhardwaj A, Goel S. Clinical risk assessment of chronic kidney disease patients using genetic programming. Comput Methods Biomech Biomed Engin. 2022;25(8):887-95. doi: 10.1080/10255842.2021.1985476. [PubMed: 34726985].

de Parades V, Fathallah N, Blanchard P, Zeitoun J, Bennadji B, Atienza P. Horseshoe tract of anal fistula: bad luck or an avoidable extension? Lessons from 82 cases. Colorectal Dis. 2012;14(12):1512-5. doi: 10.1111/j.1463-1318.2012.03034.x. [PubMed: 22443225].

Van Backer J, Jordan M, Leahy D, Moore J, Callas P, Dominick T, et al. Preemptive analgesia decreases pain following anorectal surgery: a prospective, randomized, double-blinded, placebo-controlled trial. Dis Colon Rectum. 2018;61(7):824-9. doi: 10.1097/DCR.0000000000001069. [PubMed: 29771804].

Ismail M, Kamal A, Ghobashy S, Al Baz A, Roshdy M. Comparison of pain control during trus guided biopsies between basal peri-prostatic local infiltration anesthesia versus combined topical anal lignocaine ointment and local infiltration anesthesia. J Egypt Soc Parasitol. 2015;45(2):285-9. doi: 10.12816/0017572. [PubMed: 26485846].

Reif de Paula T, Nemeth S, Kurlansky P, Simon H, Miller L, et al. A randomized controlled trial examining the impact of an anorectal surgery multimodal enhanced recovery program on opioid use. Ann Surg. 2022;275(1):22-9. doi: 10.1097/SLA.0000000000004701. [PubMed: 33351458].

Wongchai A, Jenjeti R, Priyadarsini I, Deb N, Bhardwaj A, Tomar P. Farm monitoring and disease prediction by classification based on deep learning architectures in sustainable agriculture. Ecol Model. 2022;474: 110167. doi: 10.1016/j.ecolmodel.2022.110167.

Pélissié M, Fischbach E, Lecointre L, Faller E, Akladios C. Pudendal neurolysis by laparoscopy. J Minim Invasive Gynecol. 2021;28(5):938. doi: 10.1016/j.jmig.2020.11.003. [PubMed: 33217560].

Zhu L, Zhou Z, Shen D, Chen A. Ipsilateral S2 nerve root transfer to pudendal nerve for restoration of external anal and urethral sphincter function: an anatomical study. Sci Rep. 2019;9(1):13993. doi: 10.1038/s41598-019-50484-7. [PubMed: 31570751].

Ceulemans A, De Looze D, Van de Putte D, Stiers E, Coppens M. High post-operative pain scores despite multimodal analgesia in ambulatory anorectal surgery: a prospective cohort study. Acta Chir Belg. 2019;119(4):224-30. doi: 10.1080/00015458.2018.1500802. [PubMed: 30189793].

Bendtsen T, Parras T, Moriggl B, Chan V, Lundby L, Buntzen S, et al. Ultrasound-guided pudendal nerve block at the entrance of the pudendal (alcock) canal: description of anatomy and clinical technique. Reg Anesth Pain Med. 2016;41(2):140-5. doi: 10.1097/AAP.0000000000000355. [PubMed: 26780419].

Anil VT, Nawaf A, Abdulrhman MA, Olfat MM, Arpit B, Bharat S. Multispectral image analysis for monitoring by IoT based wireless communication using secure locations protocol and classification by deep learning techniques. Optik. 2022;271:170122. doi: 10.1016/j.ijleo.2022.170122.

Amarenco G, Lanoe Y, Ghnassia R, Goudal H, Perrigot M. Alcock's canal syndrome and perineal neuralgia. Rev Neurol. 1988;144(8-9):523-6. [PubMed: 3187310].

Imbelloni L, Beato L, Beato C, Cordeiro J, de Souza D. Bilateral pudendal nerves block for postoperative analgesia with 0.25% S75:R25 bupivacaine. Pilot study on outpatient hemorrhoidectomy. Rev Bras Anestesiol. 2005;55(6):614-21. doi: 10.1590/s0034-70942005000600004. [PubMed: 19468535].

Tepetes K, Symeonidis D, Christodoulidis G, Spyridakis M, Hatzitheofilou K. Pudendal nerve block versus local anesthesia for harmonic scalpel hemorrhoidectomy: a prospective randomized study. Tech Coloproctol. 2010;14:1-3. doi: 10.1007/s10151-010-0614-z. [PubMed: 20683750].

Di Giuseppe M, Saporito A, La Regina D, Tasciotti E, Ghielmini E, Vannelli A, et al. Ultrasound-guided pudendal nerve block in patients undergoing open hemorrhoidectomy: a double-blind randomized controlled trial. Int J Colorectal Dis. 2020;35(9):1741-7.doi: 10.1007/s00384-020-03630-x. [PubMed: 32474710].

Jiaqing H, Linlin W, Abu Bakkar S, Zulkiflee A, Arpit B, Bharat S. Forecasting GHG emissions for environmental protection with energy consumption reduction from renewable sources: A sustainable environmental system. Ecological Modelling. 2023;475:110181. doi: 10.1016/j.ecolmodel.2022.110181.

Fadel M, Peltola L, Pellino G, Frunza G, Kontovounisios C. The role of pudendal nerve block in colorectal surgery: a systematic review. J Invest Surg. 2021;34(11):1238-45. doi: 10.1080/08941939.2020.1786611. [PubMed: 32633163].