If sclerotherapy left my legs with spider veins, is laser treatments the way to go, and how much does that cost?

In most cases, the recurrence of spider veins is due to venous insufficiency left untreated or remnant reticular veins. Always opt for surgeons that are board certified in venous medicine. Best, Dr. Karamanoukian 

For stubborn leg veins that don't respond to sclerotherapy or if a person can't tolerate sclerotherapy pain or thought of a needle, then lasers can be tried. Unfortunately you can develop telangiectatic matting after sclerotherapy in some cases, and laser would be worth trying on this fine network of vessels which a needle cannot get into.

If you developed "spider veins" after having sclerotherapy, you may have developed a phenomenon called matting, which appear as very fine veins- finer than what was present prior to treatment- and can be very difficult to improve with regards to the appearance. Alternatively, when some varicosities, or main trunks of superficial veins (eg Saphenous) are treated, superficial vein patterns can develop. These various conditions must be treated on an individual basis, by someone with extensive experience. There is no one treatment that is the "best"; usually multiple treatment regimens are used with the realization that an improved, but not perfect, result, can be obtained.

As already mentioned by Dr Landi, one of the pitfalls in treating spider veins is missing underlying venous insufficiency - this can be diagnosed with a thorough venous Doppler Ultrasound (Duplex scan). If there is coexistent venous insufficiency, it must be treated before spider veins are treated. Having said that, if there are new small spider vein complexes around the sites of sclerotherapy, these are called telangiectatic matting and are related to the inflammatory response and most should go away within 6 months according to the literature. If they do not, it implies that there is untreated venous insufficiency. There is a new modality of ablation called Varithena - It is new. It does not have long term outcome studies. Short term efficacy and safety is reasonable given the published data in VANISH-1 and VANISH-2. Varithena is NOT covered by insurance. EVLT is the gold standard for the treatment of venous insufficiency. A second good option is VNUS CLosure. A third option is ClariVein (mechanochemical ablation). ClariVein may or may not be covered by medical insurance. VNUS Closure and EVLT are covered by most medical insurances in the US. 

If you have had veins removed and sclerotherapy without improvement and/or worsening,  then you should have a venous reflux ultrasound to look for underlying malfunctioning valves in the saphenous system.  Laser treatment of leg spider veins does not work as well as sclerotherapy.  You should see a vein specialist for a complete venous evaluation.

The gold standard treatment for spider veins is sclerotherapy.  We use a different sclerosant (medication) for reticular veins than we use to treat spider veins.  We get almost all the spider veins with these injections.  If there are scattered spider veins that the patient wishes to treat laser is a good options.  We do offer this treatment to our patient's as well.  We charge based on 20 minutes of injections or laser treatment.  Laser is more expensive than injections.