Comparison of different approaches to small saphenous vein reflux treatment: a retrospective study in two centers

ABSTRACT BACKGROUND: Diagnosis and treatment of small saphenous vein (SSV) insufficiency is of utmost importance for relieving chronic venous insufficiency symptoms. OBJECTIVES: To investigate the efficacy and safety of five different treatment approaches among patients with SSV insufficiency. DESIGN AND SETTING: Two-center retrospective clinical study, conducted at cardiovascular surgery clinics in a local training and research hospital and a state hospital. METHODS: A total of 282 extremities of 268 patients with SSV insufficiency alone who were treated for symptomatic varicose veins between January 2012 and January 2017 were included in the study. All extremities included in the study were divided into five groups as follows: high ligation + stripping; radiofrequency ablation (RFA); cyanoacrylate closure (CAC); and endovenous laser ablation (EVLA) at the wavelengths 980 nm and 1,470 nm. RESULTS: Although the recurrence rate at six months was similar among the treatment groups, we found significant differences in recurrence rates at one year, with lower rates in the CAC, RFA and 1,470 nm EVLA groups, compared with the other treatments (P = 0.005). No sural neuritis was observed in the CAC group. The pigmentation rate was higher in the two EVLA groups (980 nm and 1,470 nm). CONCLUSIONS: Our study results showed that although CAC, RFA and EVLA at 1,470 nm seemed to be effective methods for treating SSV insufficiency alone, CAC and RFA had better aesthetic results than EVLA at 1,470 nm. We consider that endovenous non-thermal techniques for treating SSV insufficiency may be preferable because of relatively low risk of nerve injury.


INTRODUCTION
The small saphenous vein has been less suspected in the etiology of venous insufficiency than the great saphenous vein, since it is located in the posterior aspect of the leg with a relatively short length and diameter and less reflux. The prevalence of small saphenous vein insufficiency alone has been found to be 3.5%. 1 About 20% of patients with venous insufficiency symptoms are diagnosed with small saphenous vein insufficiency. 2 In particular, a small saphenous vein diameter of ≥ 4 mm has been shown to be associated with venous reflux. 2 The main symptoms of small saphenous vein insufficiency include pain and burning sensation, itching, heaviness, cramps and restless legs. Symptom severity is closely associated with the degree of chronic venous insufficiency. 3 Therefore, diagnosis and treatment of small saphenous vein insufficiency is of utmost importance for relieving the symptoms.
The saphenopopliteal junction is located 2 to 4 cm proximally to the popliteal skin crease, where it is included in the popliteal vein, and it is seen in about 83% of the cases. This junction terminates in a normal fashion in only 62% of the cases, since the medial gastrocnemial vessels and small saphenous vein terminate in a common trunk in one-fourth of patients. 4 In addition, the small saphenous vein is closely connected to the sural nerve from the apex of the calf to the ankle. 4 Because of this close connection with the sural nerve and a high number of anatomical variations in the popliteal fossa, surgical treatment of small saphenous vein insufficiency is more complicated than is treatment of great saphenous vein insufficiency. 5 Although the basic surgery for treating small saphenous vein insufficiency consists of ligation and/or stripping, inappropriate or improper ligation results in failure in 22% of the cases with one-year and three-year recurrence rates of 31.6% and 51.7%, respectively. 6,7 Over the last decade, endovascular treatment methods have become popular and have been included in the European guidelines for treatment of small saphenous vein insufficiency. 3 However, no consensus regarding the surgical treatment of small saphenous vein insufficiency has yet been established.
Moreover, although the efficacy and safety of different treatments for small saphenous vein insufficiency have already been studied, the number of studies is relatively low, compared with those on great saphenous vein insufficiency. Also, the majority of these studies were limited to head-to-head study designs.

OBJECTIVE
In the present study, we aimed to investigate the efficacy and safety of five different treatment approaches among patients with small saphenous vein insufficiency alone.   In the non-thermal procedure, the junction was compressed and collapsed under the guidance of Doppler ultrasonography and glue was continuously injected using a cyanoacrylate system, along the course of the small saphenous vein. Meanwhile, external compression was applied. Once the procedure had been terminated, compression of the small saphenous vein was maintained for an additional 30 seconds. The success rates from the endovascular techniques were evaluated through color Doppler ultrasonography.

Postoperative follow-up
For all patients who underwent conventional surgery or thermal endovascular treatment, an elastic bandage was used. After the elastic bandage was removed, class 2 (25 to 30 mmHg) compression stockings were applied for six weeks, in accordance with the guideline recommendations. 4 On the other hand, neither elastic bandages nor compression stockings were applied to the patients who received cyanoacrylate closure.
The severity of pain was evaluated using a numerical rating was given for prophylaxis of thromboembolism. The patients were examined by a specialist physician, but not by the surgeon who had performed the treatment, in the outpatient clinic at six and 12 months after the operation.

Statistical analysis
The statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS), version 17.0 software (SPSS Inc., Chicago, IL, USA). Descriptive data were expressed as the mean ± standard deviation (SD) for continuous variables and as numbers and percentages for categorical variables. The chi-square test or Fisher's exact test was used to compare categorical variables between the groups. Analysis of variance (ANOVA) or the Kruskal-Wallis test was used to assess continuous variables in independent groups, for parametric and nonparametric variables, respectively.
A P-value of 0.05 was considered statistically significant.

RESULTS
A total of 282 extremities of 268 patients who were treated for small saphenous vein insufficiency were included in this analysis. Although there was no significant difference in the recurrence rate at six months among the treatment groups (P = 0.319), we found a statistically significant difference in the recurrence rate at one year. This indicated lower recurrence rates in the cyanoacrylate closure, endovenous laser ablation at the wavelength 1470 nm and radiofrequency ablation groups, compared with the other treatments (P = 0.005) ( Table 2).
In addition, there were statistically significant differences in the numerical rating scale scores among the treatment groups.
The pain scores were lowest in the cyanoacrylate closure group (P < 0.001). The numerical rating scale scores were similar in the radiofrequency ablation and 1,470 nm endovenous laser ablation groups, with significantly lower scores than among the patients treated with high ligation + small saphenous vein stripping and with endovenous laser ablation at the wavelength 980 nm ( Table 2).   week after the operation in all the study groups. Two patients (7.1%) had thrombophlebitis in the cyanoacrylate closure group. There was no significant difference in the preoperative venous clinical severity score scores among the groups (P = 0.493). In addition, there was no significant difference in the postoperative (at one year) venous clinical severity score scores among the groups except for high ligation + small saphenous vein stripping group (P = 0.025).
Using each treatment approach, we found a statistically significant clinical improvement in the venous clinical severity score scores, irrespective of the recurrence rate ( Table 4). In a previous study, the recurrence rates were reported to be 31.6% and 51.7% at one and three years, respectively, among patients undergoing small saphenous vein ligation and/or stripping. 7 In a recent study, however, the recurrence rate was shown to be 4.3% among patients undergoing modified high ligation and segmental stripping, although the sample size was small. 10   In one study, the success rate from the procedure was reported to be 97% at six weeks, among patients with small saphenous vein insufficiency that was treated with laser ablation at the wavelength 980 nm. However, in that study, it was only possible to evaluate 60% of the patients. 19 In another study, Park et al. showed that the success rate from the procedure was 94%, one year after the procedure, among patients with small saphenous vein insufficiency that was treated with endovenous laser ablation at the wavelength 980 nm,

DISCUSSION
although it was only possible to evaluate 40% of the patients. 20 In addition, previous studies revealed that the anatomical success rate was similar between the endovenous laser ablation procedures at the wavelengths 980 nm and 1,470 nm. 14 There were some limitations to the present study. It had a small sample size with unequal sizes among the treatment groups. In addition, it was not possible to thoroughly evaluate patient satisfaction due to missing data in the quality-of-life questionnaires. Although the retrospective design can be deemed to be another limitation, we believe that this study will provide additional information for the body of knowledge on this subject, given that no head-tohead studies comparing five different methods for treating small saphenous vein insufficiency alone are available in the literature.

CONCLUSION
Our study showed that although cyanoacrylate closure, radiofrequency ablation and endovenous laser ablation at the wavelength 1,470 nm seemed to be effective methods for treating small saphenous vein insufficiency alone, cyanoacrylate closure and radiofrequency ablation had better esthetic results than those from endovenous laser ablation at 1,470 nm. Although complication rates tend to decrease with increasing experience in endovascular procedures over time, thermal ablation therapies will always imply a risk of neurological complications. Therefore, we consider that endovenous non-thermal techniques for treating small saphenous vein insufficiency may be preferable because of their relatively low risk of nerve injury.