The Loop Electrosurgical Excision Procedure (LEEP) is one of the most commonly used approaches to treat high grade cervical dysplasia (CIN II/III, HGSIL) discovered on colposcopic examination. In the UK it is known as Large Loop Excision of the Transformation Zone (LLETZ). The procedure has many advantages including low cost, high success rate, and ease of use. The procedure can be done in an office setting and usually only requires a local anesthetic, though sometimes IV sedation or a general anesthetic is used.
When performing a LEEP, the physician uses a wire loop through which an electric current is passed at variable power settings. Various shapes and sizes of loop can be used depending on the size and orientation of the lesion. The cervical transformation zone and lesion are excised to an adequate depth, which in most cases is at least 8 mm, and extending 4 to 5 mm beyond the lesion. A second pass with a more narrow loop can also be done to obtain an endocervical specimen for further histologic evaluation.
The LEEP technique results in some thermal artifact in all specimens obtained due to the use of electricity which simultaneously cuts and cauterizes the lesion, but this does not generally interfere with pathological interpretation.