Topography of haemorrhoidal arteries 117 to well established technical guidelines, the intended loca- tion of the staple line is too difﬁcult to standardize, as demonstrated by the wide range of anatomicopathologi- cal results reported by Ohana and co-workers19. Based on these data and the present ﬁndings, only a suture located within the distal 2 cm of the low rectum plays a role in the control of arterial overﬂow in patients treated with SH. However, even if SH and Doppler-guided ligation of haemorrhoidal arteries were applied, some doubts about Longo’s procedure remain with respect to the circum- ferential suture performed with the speciﬁcally designed stapling device. This type of suture cannot ensure selective ligation of haemorrhoidal arteries as it can also involve both major and minor arterial vessels. Moreover, the cir- cumferential suture could generate an unpredictable risk of venous outﬂow blockage, thus damaging the drainage system, as described previously13. The correlation between SH and rectal vasculariza- tion was highlighted in another study in which a perineal Doppler probe was used in patients who underwent SH for HD and a group of healthy subjects20. Baseline measure- ments differed signiﬁcantly between patient and control groups. Postoperative follow-up showed no signiﬁcant alterations in physiological parameters. Patients with a higher rate of recurrence of HD had higher baseline arte- rial ﬂow velocity values. The study showed that SH did not reduce arterial inﬂow in the vessels feeding the anorectal vascular plexus. The present data may explain the reasons for the failure to reduce vascular overﬂow. In that study20, the anastomosis was performed 3·5 – 4 cm above the den- tate line, a level at which most terminal arterial branches are not in the submucosa. Indeed, a meta-analysis of large- scale studies of patients undergoing SH demonstrated that these patients are more likely to develop recurrent HD with prolapse and bleeding at any time than those having conventional haemorrhoidectomy21,22. The goal of THD and DG-HAL is signiﬁcantly to reduce arterial overﬂow to haemorrhoidal piles by dearte- rialization, that is Doppler-guided ligation of the haemor- rhoidal arteries in the upper part of the low rectum. The results of these operations seem promising23 – 31. In par- ticular, most studies have shown that recurrent bleeding is limited to a minority of patients (5 – 20 per cent after THD; 1 – 21 per cent after DG-HAL)23 – 31. However, traditional dearterialization might fail to include the haemorrhoidal arteries in some sites owing to their deep location (within the muscularis propria or in perirectal fat), particularly on the anterior side of the rectum. The reported frequency of recurrent bleeding in patients undergoing dearterialization alone using the ‘high arterial ligation’ technique (31 per cent)26 supports this  2011 British Journal of Surgery Society Ltd Published by John Wiley & Sons Ltd view. When mucopexy is included in THD or DG-HAL procedures, the possibility of excluding arteries may be lower as the running suture (even one that begins in the upper part of the low rectum to perform high ligation of haemorrhoidal arteries) is usually continued by transﬁx- ing the mucosa and submucosa to the ARJ, thus involving arterial branches directed to the haemorrhoidal piles. By selectively ligating the haemorrhoidal arteries using a very precise Doppler system26, the THD technique can accurately identify the location of arterial vessels in the submucosa of the low rectum, thus achieving a signiﬁcant reduction in arterial overﬂow to haemorrhoids. Based on the present ﬁndings, dearterialization should be more effec- tive if performed 1 and 2 cm from the ARJ, where almost all of the arteries are localized in the submucosa, with a mean depth of 1·9 – 2·4 mm. In contrast, arterial ligation 3 cm from the ARJ may not be effective in certain sectors. At this level, 67·1 per cent of the vessels identiﬁed were located in the submucosa. Above this level, a smaller per- centage of submucosal arteries was found, possibly making dearterialization less accurate at higher levels. This study provides new insight into the functional anatomy of haemorrhoids, with a direct impact on patho- physiology and treatment. The location of almost all the branches of the SRA in the submucosa provides a clear tar- get for surgical treatments that recognize vascular overﬂow as a fundamental factor in the aetiology of HD. Opti- mizing dearterialization is essential for improving clinical outcome. In this regard, Doppler imaging plays a pivotal role during the surgical procedure by providing precise identiﬁcation, then guided ligation of arteries. Clinical tri- als are required to conﬁrm the therapeutic implications of these ﬁndings. Acknowledgements The authors declare no conﬂict of interest. References 1 Lucha PA. Pathophysiology of hemorroidal disease. In Surgical Treatment of Hemorrhoids, Khubchandani I, Paonessa N, Azimuddin K (eds). Springer: London, 2009; 15–17. 2 Loder PB, Kamm MA, Nicholls RJ, Philips RK. Haemorrhoids: pathology, pathophysiology and aetiology. Br J Surg 1994; 81: 946–954. 3 Thomson WH. The anatomy and nature of piles. In The Haemorrhoid Syndrome, Kaufman HD (ed.). Abacus Press: Tunbridge Wells, 1981; 15–33. 4 Shaﬁk A. Surgical anatomy of hemorrhoids. In Surgical Treatment of Hemorrhoids, Khubchandani I, Paonessa N, Azimuddin K (eds). Springer: London, 2009; 7–13. www.bjs.co.uk British Journal of Surgery 2012; 99: 112–118