The majority of acute anal fissures resolve without surgical intervention. The goals of nonoperative therapy are straightforward and consist of three components. The first component is to remove the underlying pathology responsible for the creation of the fissure. This often means the alleviation of constipation and straining, as well as avoidance of other causes of anal trauma. Frequent sitz baths, stool softeners, adequate fluid intake and a high-fibre diet are recommended. The second component involves the relaxation of the internal anal sphincter to improve blood flow and allow healing. This can be achieved through topical nifedipine, topical nitro-glycerine or botulinum toxin injections. The third component consists of reducing the symptoms from the fissure, which are typically bleeding and pain. Topical analgesics such as 2% lidocaine jelly are usually prescribed.

Local application of muscle relaxing therapy may be used in healing chronic anal fissure when considerable risk for surgery is present. These therapies include nitro-glycerine ointment, botulinum toxin, calcium channel blockers (diltiazem or nifedipine), hydrocortisone or topical anaesthetic ointment principally lignocaine, sitz baths. These therapies esp. GTN offers symptomatic relief and anti-inflammatory effects and possibility of avoiding surgery.

When chronic fissures develop, healing is more difficult to achieve. Conservative methods are likely to fail and have a higher failure rate with chronically recurring anal fissures. In these situations, the gold standard is the lateral internal sphincterotomy (LIS). Lateral internal sphincterotomy is the surgical treatment of choice for refractory anal fissures and may be offered without pharmacologic treatment failure according to the practice parameters by the American Society of Colon and Rectal Surgeons.

Although these commonly performed anorectal operations are short in duration the dense sensory supply of the perineum leads to significant post-operative pain, making adequate anaesthesia crucial.

General or regional (spinal, caudal) anaesthesia is predominantly used for anorectal surgery. Ano-rectal surgeries performed under conventional anaesthesia (GA/SA) are fraught with numerous side effects, such as, drowsiness, headache, nausea, vomiting, sore throat, backache, post operative pain and urinary retention. In addition to the need for anaesthetists’ expertise, GA/SA impose restrictions on pre/post procedural oral intake & movement, necessitate close inpatient post operative monitoring and contribute towards additional operation room time consumption, making them rather patient and surgeon unfriendly.

In the recent years several studies explored the use of local anaesthesia for anorectal surgery as an outpatient procedure with encouraging results. But significant proportion of surgeons still tend to perform LIS in the hospital, using spinal anaesthesia despite associated side effects and burden of hospitalization.

The aim of this study is to further explore the viability of peri-anal block in Lateral Internal Sphincterotomy.