A cyst is a large, abnormal sac within the body that is typically filled with fluid or pus. Cysts are sometimes caused by a bacterial infection or blockage of any of the body's many glands and ducts. Although commonly mistaken for tumors, cysts tend to be benign and non-life-threatening (although some may be unsightly or uncomfortable). Veterinarians may opt to use a needle to drain the fluid from these vessels, although sometimes, it will be necessary to perform a procedure known as 'open drainage' on the cyst, or surgical removal.  

Due to the invasive nature of the operation, the vet will usually place the dog under a general anesthetic and shave the site where they plan to make the incision. Next, using a scalpel, they will cut through the intervening tissues to reach the cyst, which they will carefully slice open. The cyst can then either be allowed to drain by itself into a pan, or suction can be applied to remove the contents. After the cyst is drained, most vets will opt to remove it entirely (especially if it has become infected). The incision is then sutured closed and the dog allowed to awaken.

Open drainage will alleviate the symptoms associated with a cyst almost immediately. If the cyst has become infected (and the infection has spread) then antibiotics will be required, but the noticeable swelling and inflammation should start to ebb away right after surgery. 

Immediately after surgery, the dog will require painkillers to alleviate any obvious discomfort. Depending on the location of the cyst that was drained, the dog may also need to be fitted with an E-collar to prevent it from tearing out its own sutures. It may also be required that the owner tries to keep exercise to a minimum until the wound is healed. Fortunately, as most cysts tend to occur in the sebaceous glands of the skin, the surgical wound will often not be especially deep and will heal in just over a month. If a serious infection was involved, however, the dog will also need to complete a full course of antibiotics, which will usually take about two to four weeks. The vet may also wish to schedule some follow-up visits to ensure that the surgical incision is healing correctly and the underlying condition is clearing up.

The normal price for open drainage of most cysts can be expected to fall roughly around $250. Depending on location, however, the price may increase further. 

Although a very potent means for dealing with problem cysts, open drainage is not without risks. Elderly dogs are especially at risk of cardiovascular failure when placed under general anesthetic, which may cause some owners to think twice before opting for the surgery. Another potential pitfall is the potential for infection of the incision site, though this can be counteracted by making sure the dog's living environment is thoroughly cleaned when they return from the clinic.

While cysts that occur deep within the body are normally the result of genetic predisposition, sebaceous cysts are somewhat avoidable. They are typically caused by blockages of the sebaceous duct and damage to the hair follicle itself. By making sure a dog's living area meets a good standard of hygiene and by properly grooming and maintaining its coat, an owner can mitigate the risk of cysts developing.