Sciatic nerve varices are an uncommon condition, however, those involved in the care of patients with venous disease should have some familiarity with them. There is a dearth of information in the literature referable to sciatic nerve varices, therefore, this article will reflect personal experience, communication with others, and small published case series.

Appropriately, sciatic nerve varices were categorized into “nonsaphenous reflux” by Labropoulos et al. These veins were described in vulvar, gluteal, lateral, and posterior thigh, popliteal fossa, and lateral knee areas – and were defined as superficial veins that are not part of the greater or lesser saphenous systems. Nonsaphenous venous (NSV) reflux was found in 72 patients and 84 of 835 limbs (10%) examined with duplex ultrasound. Of the 84 limbs with NSV, incompetent veins from the sciatic nerve were found in nine (10%). Of the entire NSV reflux group, 93% were women, and most were women with at least three pregnancies.1

Therefore, the cause of NSV reflux disease may be found in physiologic factors unique to women. Hormonal variation during progression from onset of menses through menopause and during pregnancy provides stimuli unique to the female. It is therefore plausible that isolated NSV reflux disease, uncommon in men, is an entity predominantly found in women because of a sex-specific mechanism of etiology.

Although the embryologic development of the arterial system of the lower limb is well described, this is not true of the venous system. Within weeks of the axial artery development, a peripheral border vein provides venous outflow from the limb bud. Ultimately, the tibial continuation of this disappears and the fibula portion becomes the anterior tibial, lesser saphenous, and inferior gluteal veins. The retroperitoneal postcardinal vein gives rise to the greater saphenous vein, which gives off the femoral and posterior tibial veins.2

The axial artery in utero is paired with an axial venous network, which may provide a source of collateral venous outflow in the presence of deep venous obstruction.3 With ingrowth of the femoral vein, the axial vein normally involutes, with remnants persisting as the sciatic veins of the glutei and satellite vein of the sciatic nerve.

Nonsaphenous veins are imaged best in the standing position using 4-MHz to 12-MHz linear array transducers. Occassionally, a 3-MHz phased array transducer was used to track the connection of the nonsaphenous veins with the deep system.

In the aforementioned study by Labropoulos, nine limbs (10%) and seven limbs (8%) were found to have reflux in the veins of the sciatic nerve and popliteal fossa, respectively, both of which may be easily mistaken for the small saphenous vein. However, pain often accompanies reflux of the former, because it may stimulate the sciatic nerve. In symptomatic persons, distinguishing the true anatomic site of reflux is necessary to facilitate appropriate and effective treatment. Signs and symptoms assigned to CEAP classes 1 to 3 were found in 90% of limbs.

Notably, differences in clinical severity of NSV reflux and saphenous reflux are apparent. In a previous study of 250 consecutive limbs, 92% were found to have superficial reflux and 37% were found to have skin damage, as compared with only 10% of 84 limbs with NSV reflux alone. The incidence of skin damage is significantly decreased in isolated NSV reflux (P< .0001).4

We have only seen a handful of cases of significant sciatic nerve varices warranting treatment at the Miami Vein Center in the last decade. These patients presented with debilitating pain and visible posterior thigh and calf varicose veins. Our treatment of choice is ultrasound-guided sclerotherapy with 1.5% Sotradecyl Sulfate with or without adjunctive ambulatory phlebectomy. Typically, one or more venous channels are sonographically identifiable in close proximity to the sciatic nerve. The veins are accessed percutaneously with the patient in the prone position. Because of the subsequent inflammatory response incited by sclerotherapy, we avoid treating veins adherent to the sciatic nerve. The results have been satisfactory in the few patients we have treated.

Mel Rosenblatt, MD presented his experience at the Sonoma Venous Anti-conference last year using fluoroscopic-guided sclerotherapy for the treatment of sciatic nerve varices. He also noted multiple venous channels resembling a “horse-tail” by fluoroscopy, and cautioned against overzealous treatment. He did see one sciatic neuropraxia post-procedure which resolved without sequlae.

Sciatic nerve varices are uncommon, present with pain, usually in multiparous women, and are treatable with sclerotherapy. Access can be obtained with either ultrasound or fluoroscopic imaging. Extreme care is necessary during treatment because of the close proximity of the sciatic nerve.

Jose I. Almeida, MD, FACS, RVT is the founder of Miami Vein Center and a Voluntary Assistant Professor of Surgery at University of Miami School of Medicine


REFERENCES:

1. Labropoulos N, Tiongson J, Pryor L, Tassiopoulos AK, Kang SS, Mansour MA, et al. Nonsaphenous superficial vein reflux. J Vasc Surg 2001;34:872-7. Surg 1997;84(Suppl):68.

2. Trigaux JP, Vanbeers BE, Delchambre FE, de Fays FM, Schoevaerdts JC. Sciatic venous drainage demonstrated by varicography in patients with a patent deep venous drainage system. Cardiovasc Intervent Radiol 1989;12:103-6.

3. Arey LB. The vascular system. In: Arey LB, editor. Developmental anatomy. 7th ed. Philadelphia: WB Saunders; 1974. p. 342-74.

4. Labropoulos N, Kang SS, Mansour MA, Giannoukas AD, Buckman J, Baker WH. Primary superficial reflux with competent saphenous trunk. Eur J Vasc Endovasc Surg 1999;18:201-6.