The heart pumps blood to supply oxygen and nutrients to all parts of the body. Arteries carry blood from the heart towards the body parts, while veins carry blood from the body parts back to the heart. Veins contain one-way valves to prevent the blood from flowing backwards. If the one-way valve becomes weak, some of the blood can leak backwards through the valve, collect in the vein upstream of the valve, and then become congested as the pressure builds. This congestion will cause the vein to abnormally enlarge. These enlarged veins can be seen on the surface of the skin as either varicose veins or spider veins.
Varicose veins are swollen and raise the surface of the skin. Spider veins are similar to varicose veins, but they are smaller, are often red or blue in color, and are closer to the surface of the skin than varicose veins. They are also known as telangectasias. They can cover either a very small or very large area of skin. Spider veins are connected to larger vein systems through reticular veins. As such, spider veins aren't necessary for circulation, rather they result when high pressure in veins from faulty valves stretch out the normally small and invisible surface skin veins forming abnormally distended and visible veins. Since venous pressure is highest in the legs, spider veins are most commonly found on the lower extremities, but they can be found anywhere on the surface of the skin.
At present there are two main treatment options for spider veins: sclerotherapy and surface laser treatment.
Sclerotherapy involves injecting a sclerosing solution into the vein, causing it to shrink and fade from the surface of the skin. Having this treatment can also reduce the symptoms that are commonly associated with spider veins, including, burning, itching, cramping and swelling. With time the appearance of the spider veins fades to a variable degree. Laser therapy focuses light on the vein which preferentially absorbs the light and suffers injury.
There are a number of shortcomings of sclerotherapy to treat spider veins. Serious medical complications from sclerotherapy are relatively rare, however, they may occur. Risks include the formation of blood clots in the superficial and deep veins, which is referred to as superficial vein thrombophlebitis and deep vein thrombosis, both of which are serious medical conditions that can have severe short term and long term consequences. Some deep vein thrombosis (DVT) can break loose and can travel to the lungs (pulmonary embolism), which can be fatal. Foam sclerotherapy has reportedly caused transient ischemic attacks, suggesting that the sclerotherapy can travel to the brain and cause damage. Additionally severe inflammation and adverse allergic reactions to the sclerosing solution can occur. Occasionally, skin injury known as an ulcer, a form of skin necrosis which leaves a small but permanent scar, can occur.
In addition to these potential serious reactions, there are a number of very common outcomes to sclerotherapy that are undesirable. A common cosmetic complication is pigmentation irregularity. These are brownish splotches on the affected skin that may take months to fade, sometimes up to a year or more. This is also known as staining or shadowing. Another problem that can occur is “telangiectatic matting,” in which fine reddish blood vessels appear around the treated area, sometimes requiring further injections or laser treatments to help fade the reddish discoloration. Both of these complications are thought to be related to severe and persistent inflammation that results from the chemical damage to the vein after sclerotherapy. In some cases, discoloration can persist when the hemoglobin from the damaged vein is absorbed by the skin, leaving a permanent brownish discoloration to the skin. Another problem with sclerotherapy is that the concentration and treatment effect of the sclerotherapy solution is different at different points along the vein depending on the distance from the injection site and the degree of vein branch aborization distal to the injection site. As the sclerosant travels in the vein it becomes less concentrated leading to variable zones of treatment that vary from too much to just right to too little. This effect is often undesirable to patients.
Another option is to use surface laser to treat spider veins. The energy is absorbed by the hemoglobin in the blood causing a local reaction that heats the vein and injures the endothelium and other vascular wall structures. During laser treatment, a laser is applied to the skin over the spider veins. Laser energy causes the spider veins to coagulate and shrink. Laser therapy is most effective for small and medium size spider veins because it is unable to adequately injure vessels. Most patients experience mild discomfort similar to having a small rubber band snapping against skin and treatments usually do not require sedatives, pain medications, or injections of local anesthetic. Immediately following treatment, spider veins will be darker and more visible. Over two to six weeks, a percentage of the spider veins usually fade while others persist, thus more than one treatment is necessary. Retreating the areas requires a long treatment interval because the cumulative effect can cause skin necrosis or sloughing. With both sclerotherapy and laser therapy the post treatment skin can react unfavorably to sunlight in the healing phase, leading most practitioners to caution against sun exposure either before or after treatment. Many patients seeking treatment for spider and reticular veins are doing so due to their desire to obtain sun exposure, thus limiting treatment sessions to times when patients can reliably expect to keep their veins out of the sun before or after the treatment.
Clearance is neither complete nor immediate with both sclerotherapy and surface laser, which have significant undesirable effects. In each case there is enough injury to cause a wound healing response as the vein fades away over time. Failure to clear the spider vein occurs when the injury is insufficient to the vein wall structure. In the case of sclerotherapy, this happens in the far reaches of vein from the injection site, resulting in uneven and incomplete results. With laser, this occurs when there is insufficient heat generated to damage the inside of the vein. The larger the vein, the more likely the laser to be unsuccessful in clearing the spider vein. Alternatively, sclerotherapy can result in a prolonged wound healing phase where the vein is visibly damaged, yet it takes months to become invisible as the body's inflammatory system works to clear the damaged vein through the wound healing process.
Both sclerotherapy and surface skin laser involve injuring the internal vein structure in a fashion that results in thrombosis of the vein and injury to the vein. With sclerotherapy, the injury is in the form of a chemical irritant to the internal lining of the vein, known as the endothelium. With surface laser, a focused beam of light with variable absorption characteristics is utilized to travel from the hand piece through the skin to injure the underlying vein. Vein injury triggers in a wound healing response. The wound healing response is known to include following steps: 1) Inflammation; 2) FibroProliferation; 3) Contraction and 4) Remodeling. It is generally understood that a wound will not heal until the initial inflammatory step is complete. Thus minimizing inflammation is key to the speed and completeness of treatment.
This is the problem with sclerotherapy. In sclerotherapy the degree of endothelial and sub endothelial damage is variable along the length of the treated vein, as is the degree of inflammation. Patients complain of feeling pain and heat along the treated veins for many months. Areas of entrapped coagulated blood usually associated with discolorization, all of which patients find undesirable. When this occurs, return visits are often required to puncture and drain these areas. Residual areas of entrapped, inflamed and coagulated blood persist and impact the degree of discomfort and lessen patient satisfaction. This can persist for many months and sometimes for more than a year. Most patients require multiple treatments and degree of residual discolorization and discomfort lengthen the interval between treatments. Due to these limitations, patients often choose not to continue with treatments and they are left with residual discoloration.
An alternative vein treatment method is ambulatory phlebectomy, also known as phlebectomy. Phlebectomy is a technique commonly utilized for larger diameter, branch varicose veins that are visible by bulging out of the skin when the patient is standing Phlebectomy always involves cutting the skin, fishing out the vein, and pulling on it to break or injure the vein, and then applying pressure. With this technique, the vein is marked with the patient standing, and then once the overlying skin and subcutaneous tissues are anesthetized, a small incision is made and a hook is inserted into the incision to hook the vein. Once the vein is hooked, the operator pulls the hook and vein out, snapping the vein, most often removing a small segment of vein in the process. This process is repeated, on average for 10 to 20 incisions per treatment session. The disrupted veins are then compressed in a dressing that allows the vein segments to clot off, preventing continued bleeding. Alternatively, some surgeons ligate each end of the vein so that the small vein segment can be removed without allowing the remaining segments to continue to bleed. Incision sizes range from 5 cm to 0.5 cm. Small diameter veins, such as reticular veins and spider veins are generally too small to be treated with this technique.
One problem with current ambulatory phlebectomy is that that it is difficult to find the veins when the patient is laying down for treatment. Usually the veins are marked with a permanent felt tip pen when the patient is standing. Then the patient is put in the supine or prone position for treatment. At this point, the veins become decompressed and no longer visible. When attempting to perform phlebectomy, the area to be treated is anesthesized, then a knife blade is used to incise the skin overlying the vein that was marked with a felt tip pen. A crochet hook or specially designed phlebectomy hook is put into the wound and the operator attempts to find the vein. Once the vein is found, it is pulled out of the incision and either avulsed or clamped, cut and tied. If the skin is lax and moves relative to the vein when the patient goes from the standing to laying position, the operator can be unsuccessful in finding the vein, especially if the incision in the skin is small.
An additional embodiment is endovenous treatment. With endovenous treatment, a catheter is threaded into a vein, usually under ultrasound guidance, and the catheter tip uses laser, radiofrequency or steam to damage the inside of the vessel wall. As the catheter is withdrawn, the length of the vein is treated. Ideal veins for endovenous treatment are larger diameter (usually 3 mm to 20 mm), relatively straight (because curving veins cannot be cannulated as successfully), and remote from the surface of the skin (because the skin can be burned if the vein is too near the skin, resulting in significantly increased pain and discoloration). Thus this is usually reserved for the great and small saphenous veins, and occasionally, larger straighter incompetent perforator veins. Disadvantages of endovenous therapy include the limitations on the type of veins (larger, straight, deeper) that can be treated. Furthermore, the degree of damage surrounding the vein is variable, ranging from too little (and thus failed treatment) to too severe, leading to pain and collateral damage to other vessels and nerves. One device used to treat spider veins is described in U.S. Pat. No. 6,224,618 to Gordon. Gordon teaches a handheld device that consists of a sharp trocar-like tip divided into two tines for straddling a vein and permitting the physician to cut the vein by rotating the instrument. Although this technique and device have proved successful there is a continuing need for improved spider vein obliteration tools.
USPTO Backgrounds
USPTO Backgrounds