The evolution of endovenous radiofrequency ablation (VNUS Closure) of varicose veins
Department of General and Vascular Surgery
Department of General and Vascular Surgery-
Middlesex – UK
Extraluminal and intraluminal devices using monopolar energy have been utilized in the past to treat varicose veins. This report describes the development of these minimally invasive electrosurgical techniques.
Saphenous nerve injury, full-thickness skin burns, and high recurrence rates were the usual complications after such procedures. Radiofrequency ablation (VNUS Closure) is a new endovenous computer-feedback controlled application of bipolar electrothermal energy which reduces thermal spread to neighbouring tissues, thus avoiding the above problems.
Preliminary clinical VNUS Closure results demonstrate that this is a safe and effective minimally invasive alternative to the traditional high saphenous tie and strip.
Great saphenous vein reflux is commonly treated by high ligation of the saphenofemoral junction (SFJ) and stripping of the great saphenous vein (GSV) from groin to below knee level.1-3 Nonetheless, dissatisfaction with the above procedure incited many surgeons to develop alternative ways in treating varicose veins: ambulatory phlebectomy,4-6 injection sclerotherapy7,8 and cryotherapy.9
Ambulatory phlebectomy and sclerotherapy do not address the underlying reflux, and therefore a significant number of recurrences occur post-procedure.10,11
More recently a new minimally invasive endovenous technique (VNUS Closure Sunnyvale San Jose) has evolved, which obliterates GSV reflux from within the vein as it utilizes bipolar electrothermal energy.12,13 Various electrothermal devices have been used in the past employing mainly monopolar energy via an endoluminal or extraluminal route to ablate the GSV. This article describes the evolution of electrosurgical techniques in the treatment of varicose veins since their introduction by Politowski in 1959.14
The following search strategy was conducted on the Medline database: I. Varicose veins AND thermal energy II. Varicose veins AND Electrocoagulation III. Varicose veins AND Electrofulguration IV. Varicose veins AND diathermy. All abstracts were reviewed with subsequent analysis of relevant articles and cross-references.
THE EVOLUTION OF ELECTROSURGICAL
TREATMENT OF VARICOSE VEINS
Politowski applied endovenous high frequency current via rod-shaped electrodes following ligation of tributaries and ligation of the SFJ. He also utilized a second incision at the ankle in order to advance the electrode from distal to proximal. He also treated the short saphenous vein in the same manner after ligation of the saphenopopliteal junction, which was preoperatively identified by phlebogram. Postoperatively, elastic bandages and splints were applied to immobilize the patient until the 12th postoperative day. Politowski confirms in his animal experiments the efficacy of electrocoagulation of veins, demonstrating the histological changes of vein wall thickening with a closed lumen. His study included 231 patients, of whom 22 underwent the procedure for concomitant leg ulceration and 12 for cosmetic reasons only. Third-degree burns were encountered in 8 patients, requiring subsequent excision, 3 patients developed a wound infection, 4 patients suffered a permanent saphenous nerve injury, and 1 patient developed a pulmonary embolism. Seventy out of the 231 patients were followed up for 4 years, and according to the report, all of them sustained marked regression of their symptoms and only 6 patients developed recurrence of their varicosities. Politowski’s conclusion at the time was that his results were encouraging, although 2 years later when he presents the results from 389 patients15 he admitted that the technique demands a certain dexterity and experience in order to avoid saphenous nerve injury which occurred in 20% of his patients, and skin burns (complication rate not mentioned in his article).
Werner describes the use of percutaneous diathermy in order to ablate varicosities and perforators. In his series the GSV was still treated with a high tie and strip down to the ankle. A timer was used in order to control discharge at the electrode to avoid skin burns. Postoperatively the leg was bandaged and the patient was allowed to walk on the same day. Forty patients were studied in this group with a follow-up of 1 year. Skin burns and paresthesia were noted, but the author gave no figures. Nevertheless, the author concluded that the operation accomplishes its purpose, with cosmetic results superior to the prevailing method.16
Schanno17 utilized a similar high-frequency electric generator with an internal timer in order to treat primary and secondary varicose tributaries of the GSV and short saphenous vein (SSV) by a subcutaneously placed electrode. Again a standard high tie and strip of the GSV and SSV was performed prior to electrocoagulation of the tributaries. In his study group 34 patients had 52 legs treated. He distinguished between excellent (18 patients), good (13), and poor (3) results depending on the necessity of postoperative sclerotherapy. Five skin burns were noted in 4 patients but no peripheral nerve injuries were seen in his study group.
In 1972 Watts18 used a fluon-coated wire attached to a conventional diathermy machine in order to ablate the GSV from within the lumen introducing the wire at the ankle and advancing it to the SFJ after having the SFJ ligated. The wire is withdrawn at 2.5 cm per second after elevation of the leg. Unfortunately no data is given by the author regarding the number of patients treated and complications encountered. Watt states though that there is no significant difference in the results, comparing it with conventional stripping.
O’Reilly19 used filiform endovenous diathermy which he passed from the groin distally to below knee after crossectomy. Short 1-second bursts of diathermy discharge were used at 1-to 2-cm intervals as the catheter was gradually withdrawn. His report analyzes 68 procedures in 48 patients with a maximum follow-up of 3 years. Two patients developed transient infrapatellar anesthesia. Only one skin burn occurred in his series, and one patient died secondary to a myocardial infarction.
Stallworth used a high-frequency cautery probe to obliterate tributaries and perforators subcutaneously through 1 to 2 mm incisions. He treated 705 patients with a follow-up varying from 6 months to 12 years. He stated that his results have been excellent in patients with primary varicose veins, and estimated a saving of $385 per patient.20
Gradman21 tried in 1994 to determine whether venoscopic electrocautery of saphenous vein tributaries can eliminate reflux into varices and reduce the need for further avulsion or sclerotherapy. All of the 12 patients studied underwent a preoperative duplex scan to identify and mark tribu-taries of the GSV. Retrograde venoscopy as described in a previous article22 was performed through a transverse venotomy at the proximal GSV. The catheter is advanced into the tributaries and 1-second bursts with 10 to 15W energy are delivered to the veins and repeated at 1-cm intervals up to its junction to the GSV. In 9 patients (75%) the GSV was completely preserved and in 3 patients (25%) the GSV was partially thrombosed near the cannulated tributaries. Seven patients improved clinically but required further sclerotherapy, and one patient developed a skin burn. However, the follow-up in this series was only 2 months.
Chevru et al, had described previously the use of endovascular coils and balloons under angiographic control to obliterate arteriovenous fistulas intraoperatively at the time of tibial bypass in diabetic patients with in-situ saphenous vein bypass.23 However, this technique has never been utilized for the treatment of varicose veins.
Recently, endovenous radiofrequency ablation has been used to treat an incompetent GSV (VNUS Closure, developed by VNUS Medical Technologies, Sunnyvale, CA, USA). This catheter-based device delivers bipolar electrothermal energy via electrodes with a temperature feedback loop using a thermocouple, which allows it to be applied in a controlled manner. This ensures transmural heating of the vein wall while minimizing thermal spread to adjacent tissues. The technique is described in greater detail elsewhere.12 Reports are appearing in the literature of the success of VNUS Closure in treating GSV-reflux without the previously encountered skin burns and high rates of saphenous nerve paresthesia.24-26 The efficacy of this technique has also been confirmed by ultrasound scan surveillance of the permanently closed GSV and surveillance of the SFJ, which does not exhibit any signs of neovascularization.27 This has been proposed as the principal cause of recurrent SFJ incompetence in previous studies.28,29 VNUS Closure can also be utilized to treat reflux in side branches of the GSV and recurrent varicose veins where an incompetent GSV30 persists either due to neovascularization at the SFJ or a persisting midthigh perforator.31
Boné first described in 1999 the technique of endoluminal laser energy application for the treatment of varicose veins.32 Since then this modality has been further developed at the Cornell University in New York to treat the incompetent GSV.33,34 Endovascular laser therapy (EVLT) causes nonthrombotic vein occlusion by thermal destruction of the vein wall via 810-nm-wavelength laser energy. Excellent clinical results are observed at 1 to 3 years, with this technique with a low complication rate.34,35 Both novel endovenous procedures, VNUS Closure and EVLT, appear to be a safe and effective minimally invasive alternative treatment option for patients with GSV reflux, but both techniques are still subject to ongoing investigations.
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