BackgroundHemorrhoids are a common condition that presents with bleeding per rectum, pain at rest and defecation, mucosal discharge, and prolapse. Surgical hemorrhoidectomy is the treatment method of choice for Grade 3 and Grade 4 hemorrhoids. Hemorrhoidectomy is associated with postoperative pain and no single surgical technique has been proved to significantly reduce the pain. We analyzed in our study the effect of lateral internal sphincterotomy with hemorrhoidectomy on postoperative pain, anorectal function, and retention of urine after the Milligan and Morgan technique. MethodsThis randomized, prospective, and comparative study included 200 Grade 3 and Grade 4 hemorrhoids patients who were scheduled for surgical management. The patients were classified randomly into two groups with an equal number of participants: Group A underwent Milligan & Morgan open hemorrhoidectomy and Group B underwent lateral internal sphincterotomy (LIS) in addition to Milligan and Morgan open hemorrhoidectomy. Postoperative pain was recorded using the Visual Analog Scale (VAS) score for up to 48 hours. Postoperative bleeding, urinary retention, and bowel and gas incontinence were noted. Long-term follow-up at six and 24 months for anal stenosis, anal fissure, incontinence, and recurrence was also noted. ResultsPatients who underwent LIS showed a significant reduction in postoperative pain at 12 hours (p=0.0008*), 24 hours (p=0.000*), and 48 hours (p=0.003*); the time taken to request rescue analgesia was similar between the two groups (p=0.07). Side effects, such as postoperative bleeding and urinary retention, were significantly lower after LIS (p=0.001* and p=0.01*, respectively), and gas incontinence was significantly higher after LIS (p=0.002*). The long-term outcomes of anal fissure were significantly higher without LIS at six months (p=0.02*) and 24 months (p=0.04*) and those of anal stenosis were significantly higher without LIS at six months (p=0.04*). ConclusionsFrom our study, we conclude that postoperative pain, bleeding, and urinary retention were significantly lower after LIS, and gas incontinence was transient. The long-term outcomes, which included anal stenosis and anal fissure, were significantly lower after LIS. However, bowel and gas incontinence and recurrence were not altered. Therefore, we conclude that the addition of LIS to hemorrhoidectomy improves patient outcomes in terms of postoperative pain and anorectal function.