Introduction

Chronic venous insufficiency (CVI) is a common health problem that affects the quality of life in many individuals [1]. CVI can result from incompetent either deep or superficial systems [2]. One of the valuable classification systems for CVI is the Clinical-Etiological-Anatomical-Pathophysiological (CEAP) classification; this classification demonstrates the differences between the CVI patients according to the level of the incompetent segment [3], and gives us the opportunity to individualize the treatment for each patient and prevents recurrence [4].

Short saphenous vein (SSV) reflux is an important and often overlooked cause of chronic venous insufficiency. Its manifestations are often confused with reflux in the great saphenous vein (GSV). Short saphenous veins exhibit several anatomical variations in course and site of drainage in addition to proximity to sural nerve which require careful vein map** especially with the recent era of thermal ablation [5] to avoid probable neural injury and deep vein thrombosis (DVT) [6]. An overlooked incompetent short saphenous vein may be responsible for residual or recurring symptoms after varicose vein interventions [7].

The development of endovascular techniques in the treatment of varicose veins reduced the hospital stay and the recovery period; endovenous thermal ablation was one of the accepted tools worldwide, yet it has certain limitation regarding the diameter of the vein and the site of incompetent segment, the thermal injury to the skin and the nearby structures [6]. The incidence of nerve injuries has been infrequent in the published series, but an insufficient amount of data exists to accurately quantify it. In 2017, Budak et al. performed SSV ablation procedures for 52 patients and the results showed 100% success rates and improvements in quality of life; the incidence of sural neuritis was 3.8%; this report opens the door for using such technique widely [7].

This study aimed to evaluate the outcome of radiofrequency ablation of incompetent short saphenous vein as well as its variants in patients suffering from chronic venous insufficiency.

Patients and Methods

This prospective study was conducted on 56 patients who suffered from symptoms of chronic venous insufficiency (either primary or recurrent) attended to outpatient clinic and were referred for duplex scan to affected limb/s where short saphenous vein insufficiency was detected as reverse flow in the saphenous vein > 0.5 s (Grade I) after calf compression or with straining. Cases who had secondary varicosity due to prior DVT, not fit, or refused thermal ablation were excluded. Vein map** (beginning from mid of the leg until termination), diameter, and wall condition (healthy/fibrosed) were done for all veins showing reflux. All patients were assessed clinically according to CEAP classification and VCSS; also, they should fulfill AVVQ before operation, and sign informed written consent for operation and publication. An IRB approval was received (R.20.07.940—2020/07/15).

Duplex study was done using 7.5 MHz superficial probe (Logiq 7, GE machine). The examination begins with the patient in the recumbent position to assess the patency of deep veins. Then, the patient was asked to stand up and the rest of the examination was performed to assess the presence of incompetent veins/valves and incompetent saphenofemoral/saphenopopliteal junction; diameter and grade of incompetence were determined for each incompetent segment; special attention was given to assess course and termination site of incompetent SSV; it is marked on patient’s skin to guide further procedures (Fig. 1). Duplex scan was done 3–7 prior to thermal intervention and repeated 1-week post-intervention. Whole examination required 20–30 min.

Fig. 1
figure 1

Pre-operative vein map** of incompetent short saphenous vein (SSV) (red line) and its connection with an incompetent great saphenous vein (GSV)

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Pre-operative duplex evaluation was done while patient was standing to ensure the diagnosis and detection of the reflux. After giving spinal anesthesia, the short saphenous vein (SSV) was accessed using needle and 7 Fr sheath from supine position at the level of the mid leg with slightly flexed and laterally rotated knee (Fig. 2). The radiofrequency catheter ClosureFast® (Covidien IIc, MA, USA) was advanced through the short saphenous vein until it reaches 2 cm before the saphenopopliteal junction. Some patients had continuation of the short saphenous vein in the thigh that joined the great saphenous vein; in these patients, thermal ablation of the incompetent segment was adjusted to follow vein map**. Tumescent anesthetic solution (10 ml lidocaine 2%, 20 ml 8.4% sodium bicarbonate, 1 ml adrenaline in 500 mL 0.9% saline) was injected by hand injection aided by ultrasonographic guidance all around the short saphenous vein tremendously aiming to protect the sural nerve from the heat liberated from the catheter. Ablation of the incompetent small saphenous vein was performed from below saphenopopliteal junction by 2 cm until the site of mid leg. After completion of the procedure, wrap** of elastic bandage was done and kept for 1 week.

Fig. 2
figure 2

Access of the short saphenous vein (SSV) using 7 Fr sheath in supine position and slight external rotation

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Every patient had follow-up visits 1-week post-procedure, then after 1, 6, and 12 months. Evaluation made by scoring systems (venous clinical severity score), quality of life score (Aberdeen Varicose Vein Questionnaire) [8] 1-month post-procedure, results were compared to pre-operative evaluation. Duplex report included dimensional measures, state of reflux, residual patency of the ablated segment and all these findings were compared to pre-operative data. Values for pre- and post-intervention scores were compared by Student’s t test (for Gaussian) or Wilcoxon test (for non-Gaussian); a statistical threshold of less than 5% was used as the criterion for statistical significance.

Results

This study was conducted on 56 patients from July 2020 to October 2021; 34 patients (25 ladies and 9 gentlemen) met the inclusion criteria with median age 35 (IQR 9); the total number of incompetent SSVs in examined patients was 52; 33 of them had associated incompetent great saphenous vein (GSV); 4 patients had a history of unilateral great saphenous vein strip** (Table 1).

Table 1 Patient’s demographics (n = 34)
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Duplex scan revealed 22 limbs with anatomical variations for the short saphenous vein; the SSV had one communication to the GSV in 15 limbs, one SSV had 2 communications with GSV, five SSVs terminated in deep veins in mid-thigh, and one SSV terminated at the superior gluteal vein. The mean diameter of SSV was 4.9 mm SD 1.0, and the mean time frame for SSV ablation procedure in each leg was 37.5 SD 13.7 min (Table 2).

Table 2 CEAP C classification, radiographic and operative findings (n = 52 legs)
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Technical success was reached by total occlusion of the SSV at the end of the procedure confirmed by the duplex US which occurred in 100% of the cases. The adverse effects were in the form of post-operative pain 18%, bruises and ecchymosis in 68%, swelling in 18%, phlebitis in 9%, paresthesia along the distribution of sural nerve in 9%, and none of the patients had suffered from deep vein thrombosis (DVT) (Table 3).

Table 3 Incidence of complications (pain, ecchymosis, swelling) (n = 34)
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The median follow-up period was 365 days (IQR 6), 91% of the patients completed 6-month follow-up, and 79.4% of patients completed 12-month follow-up; the occlusion rate at 6 months was 98.1% and at 12 months was 94.2%. The median VCSS reduced from 13.5 (IQR 12) pre-operatively to 3 (IQR 6) 1-month post-operatively [Z < 0.001], while the median AVVQ was reduced from 27.1 (IQR 18.8) to 5.6 (IQR 7.2) [Z < 0.001] 1 month after the procedure (Figs. 3 and 4). The distribution of patients according to CEAP C classification has been shown in Fig. 5.

Fig. 3
figure 3

Boxplot diagram for venous clinical severity score (VCSS) pre-operative and 1-month post-operative

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Fig. 4
figure 4

Boxplot diagram for Aberdeen Varicose Vein Questionnaire (AVVQ) pre-operative and 1-month post-operative

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Fig. 5
figure 5

Patient distribution according to CEAP C classification pre-operative and 12-month post-operative

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Discussion

Short saphenous vein reflux is one of the great concerns in the management of chronic venous insufficiency; being responsible for approximately 15% of CVI causes [9], it also acts as a back-door for recurrence of symptoms after treatment of patients for great saphenous vein incompetence; difficult localization of the saphenopopliteal junction and different anatomical variations in addition to close proximity to sural nerve make the treatment of saphenous vein incompetence a challenging procedure [10].

The usual course of SSV begins posterior to lateral malleolus as a continuation of lateral marginal vein of the foot, closely related to the sural nerve. It turns upwards along the lateral aspect of tendocalcaneus, until it reaches the upper leg where it perforates the deep fascia in the lower part of the popliteal fossa between the heads of the gastrocnemius muscle ending at the popliteal vein. Five types of termination were classified; Type A: SPJ about 5 cm above the knee crease (83%), further subdivided into A1 and A2 according to absence or presence of a common trunk with the medial gastrocnemial veins respectively. Type B: SSV terminates at popliteal vein ≥ 5 cm above the knee crease (6%). Type C: the SSV does not end at the popliteal vein, but it extends to GSV by the Giacomini vein (5%). Type D: SSV ends into plexiform veins in the thigh muscles (5%). Type E: SSV ends at the level of the leg and does not extend to popliteal fossa (1%) [11]. However, to avoid miscommunications and mix with other classifications, we prefer to describe the course and termination of each SSV combined with map** to ensure proper recognition of the SSV by the clinician.

In the last 3 decades, the endovenous tools replaced the surgery [12]; endovenous laser ablation (EVLA) has shown moderate evidence of superiority than conventional surgery in short saphenous vein reflux regarding the rate of recanalization and quality of life [13]; SSV ablation and risk of sural nerve injury were due to the close relation of the short saphenous vein to the sural nerve; usually, the sural nerve may be lateral to SSV in majority of cases (87% the SSV is medial to the sural nerve and 13% lateral to it at the level of gastrocnemius muscle origin) [14]; this variability in relation makes accurate identification of sural nerve is difficult and makes it liable for iatrogenic injury either during dissection around the SSV or during strip** [14]; this renders a complication rate in 20% of the cases undergoing surgical removal [15]. These statistics are not clear in radiofrequency ablation procedure due to paucity of data and reports, but theoretically, the injection of generous intumescent anesthesia around the vein under the guidance of ultrasound aids in prevention of neural injury in radiofrequency ablation; in our study, the percentage of neural paresthesia was 9%; all of them resolved completely after 2 weeks up to 6 months post-procedure; according to reported studies, the percentage varied from 0 to 26% [9]; this percentage is lower than conventional surgery (20%) but still higher than EVLA (less than 2%) [16].

In our study, we performed 52 ablations for incompetent short saphenous veins in 34 patients; we started to ablate the SSV 2 cm apart from saphenopopliteal junction; we did not report any cases of DVT; in some studies, DVT incidence ranged between 0 and 8% [9, 17]; we achieved total occlusion of short saphenous vein in all patients; this success translated into significant reduction of venous clinical severity score from 13.5 (IQR 12) to 3 (IQR 6), and improvement of the quality of life according to Aberdeen varicose venous questionnaire from 27.1 (IQR 18.8) to 5.6 (IQR 7.2). SSV variants were recorded in 22 limbs (42%) which is relatively a high incidence that could be explained by the fact of selection of cases suffering from recurrent lower limb varicosities. Thermal ablation procedure was adjusted according to vein map** in these cases leading to higher success rate.

In this prospective case series study, despite the good results for radiofrequency ablation in SSV, the level of evidence of its effectiveness is still low; due to the absence of a control group, small number of cases recruited, short follow-up period, but in the future, the application of this technique on large scale of patients with comparing it to other modalities as EVLA, sclerotherapy, and conventional surgery, plus increasing the follow-up duration can raise the level of evidence for such interventions.

Conclusion

Endovenous radiofrequency ablation can be considered in the treatment of patients with chronic venous insufficiency due to short saphenous vein (SSV) incompetency, duplex assessment to delineate SSV course and variants with further adjustment of treatment plan ensures higher success rate and lower incidence of complications.