2 The procedure
2.1.1 The procedure is used for patients with either healed or active ulcers (CEAP classifications 5 or 6), caused by chronic venous insufficiency, in whom incompetent calf perforating veins are thought to be an important contributing factor, particularly where conservative management (such as leg elevation, compression therapy and medication) has failed. Deep venous occlusion and/or infected ulcers are usually contraindications to SEPS.
2.1.2 SEPS has also been used for patients with post-thrombotic valvular incompetence, but there is now evidence that this particular group of patients may have poorer outcomes following SEPS, compared with patients with primary valvular incompetence.
2.1.3 SEPS is a minimally invasive alternative to open subfascial perforator vein surgery.
2.2.1 Preoperative evaluation is performed by duplex scanning of the superficial, deep and perforator venous systems to diagnose both valvular incompetence and obstruction. During the operation, the limb is exsanguinated and two endoscopic ports are placed in the subfascial space in the calf at sites remote from the area of venous ulceration. A space-maker balloon is introduced and inflated in this subfascial space to improve access. Carbon dioxide is then insufflated to facilitate dissection. The incompetent perforating veins are clipped and divided with endoscopic scissors or, alternatively, coagulated and divided with an ultrasonic coagulator (harmonic scalpel).
2.3.1 One randomised controlled trial (RCT), two non-randomised comparative studies and two case series were reviewed. The studies showed great potential for bias: there were large losses to follow-up, considerable discrepancies in length of follow-up between SEPS and open procedure groups, and uncertainties about patient selection. The studies that compared SEPS with open procedures found ulcer-healing to be 85% (17/20 patients) to 90% (18/20 patients) in the SEPS groups and 100% (18/18 and 19/19 patients) in the open procedure groups. Ulcer recurrence rates in these studies were 12% (2/17 patients) to 28% (5/18 patients) in the SEPS groups and 22% (4/18 patients) to 68% (13/19 patients) in the open procedure groups. For more details, refer to the 'Sources of evidence' section.
2.3.2 The Specialist Advisors considered the efficacy of this procedure to be unproven. They also noted that the indications for SEPS are not well established.
2.4.1 The results of the RCT showed a considerably lower wound infection rate in the SEPS group of 0% (0/20 patients) compared with the open procedure group's rate of 53% (10/19 patients). This trial was closed early because the high rate of wound infection in the open procedure group made it unethical to continue. One of the non-randomised comparative studies also found the wound complication rate to be lower in the SEPS group (7%, 2/27 patients) when compared with the open procedure group (45%, 13/29 patients). For more details, refer to the 'Sources of evidence' section.
2.4.2 Other reported complications of the SEPS procedure included nerve injury and deep vein thrombosis (DVT). The reported incidence of nerve injury ranged from 0% (0/20 patients) to 7% (2/30 patients); and incidence of DVT ranged from 0% (0/27 patients) to 14% (21/146 limbs). The study that reported 14% incidence of DVT originally had a total of 254 patients, of which data from only 130 patients (146 limbs) were analysed due to high loss to follow-up. In this study, DVTs occurred in 2 patients directly after surgery and in an additional 19 patients during the follow-up period. For more details, refer to the 'Sources of evidence' section.
2.4.3 The Specialist Advisors noted safety concerns similar to those reported in the studies: wound infection, nerve injury, DVT and haematoma.
2.5.1 It was noted that the indications for this procedure are uncertain, and that careful patient selection is particularly important.
 CEAP is a standardised classification system for rating the severity of venous disease where 'C' is for clinical signs, 'E' is for etiologic classification, 'A' is for anatomic distribution and 'P' is for pathophysiologic dysfunction.