Which is my pathology ?
What is a synovial cyst?
It’s an abnormal mass that can develop in different places on your hand. The most common position is on the back of the wrist. However, it can also appear at the front of the wrist, or more rarely at the base of a finger. This mass is made up of hyaluronic acid and forms at the wrist joint. The precise causes triggering its appearance are not yet well understood. Synovial cysts are most common in young adults, but can sometimes be found in children or the elderly. They usually form spontaneously, for no particular reason, and gradually increase in size over several months. Often, the patient does not notice the lump until late in life, perhaps after trauma or intense exertion. It is common for the size of the mass to vary with joint use. These cysts are always benign and present no risk of transformation into cancer. However, they may cause pain or aesthetic discomfort.
What treatment options are available?
Given the generally benign nature of the condition, it is possible to opt for a surveillance approach and not undertake any treatment. If the synovial cyst causes little or no pain, it’s perfectly feasible to leave it in place, apart from the mass itself and its possible cosmetic consequences. In some cases, a needle puncture may be performed to drain the fluid contained in the cyst, followed by a corticosteroid injection. However, it’s important to note that the recurrence rate is high with this approach, as the cyst is not removed but simply drained. Despite this, this procedure can quickly and effectively relieve pain without the need for surgery. If the synovial cyst is large and has a significant local impact, surgical removal may be considered. As far as pre-operative examinations are concerned, it is generally not necessary to carry out additional tests to confirm the diagnosis of synovial cyst, as the diagnosis is based primarily on clinical examination. However, your doctor may consider ordering an ultrasound and/or X-ray. Although synovial cysts are not visible on X-rays, these tests can help identify a possible underlying cause (such as osteoarthritis or the after-effects of trauma). MRI is generally not the examination of choice, and is not performed as a first-line procedure.
The procedure
The most commonly used anesthesia is locoregional anesthesia, which means anesthesia limited to the upper limb only. In special cases, general anesthesia may be considered. The anaesthetist will explain these options during your pre-anaesthetic consultation. A cuff will be placed at the root of your arm to act as a tourniquet and reduce bleeding, making the surgical procedure safer. The surgical procedure involves removing the tissue pocket containing the synovial fluid. Generally, this is achieved by a short skin incision of a few centimetres, centred on the swelling. Occasionally, removal may also be performed arthroscopically. In this case, the surgeon makes small punctiform openings of a few millimetres around the wrist, at a distance from the cyst. Certain events can interfere with the smooth running of the operation. For example, any local infection in the skin close to the area to be operated on may lead to postponement of the operation. A general infectious episode, even a minor one such as a cold, can also lead to the operation being postponed. Failure to follow preoperative instructions can also result in a potential postponement. It is therefore crucial to follow prescriptions, particularly with regard to preoperative showers, fasting schedules and stopping certain medications. Complications during the operation are possible, including temporary damage to small peripheral nerves. This may explain post-operative skin sensory disturbances around the incisions. As a rule, these disturbances regress. Accidental injury to tendons in the vicinity of the surgical area is very rare. Post-operative complications can also occur. As with any joint surgery, infectious complications can occur. This can be as simple as a skin infection around the scar, but can sometimes – although much more rarely – lead to a deeper infection that can reach the joint, in which case it becomes an emergency. Any redness, pain, swelling or abnormal discharge from the scar should prompt you to contact your surgeon as soon as possible. Post-operative bleeding may also occur, sometimes resulting in a hematoma. In most cases, this bleeding is limited, but in certain situations, a puncture or re-operation may be necessary. Post-operative pain is relatively common in the first few weeks, particularly when mobilizing the wrist. The opening of the joint capsule required to completely remove the cyst can lead to scarring fibrosis in the capsule, causing temporary pain, particularly when the wrist is flexed. Occasionally, excessive and abnormal stiffness may develop. This is generally attributed to algoneurodystrophy (increased sensitivity to pain). As with any surgical procedure, the scar may remain visible or even be perceived as unsightly.
After surgery, it is common for your surgeon to prescribe dressing care for the scar. If the sutures are not absorbable, they will generally be removed within two weeks of the operation. Post-operative immobilization is not systematic, but a semi-rigid Velcro splint may be prescribed for a few weeks’ comfort. Physiotherapy sessions are not systematic. Recovery of the operated joint’s suppleness is generally achieved through self-education movements. Moderate pain is common after surgery, and can be relieved by painkillers. These pains generally occur when stretching the operated joint, in connection with the deep healing process. Potential pain diminishes over the weeks and is generally moderate. Despite complete and meticulous excision, there is a significant risk of recurrence of the synovial cyst (at least 10%).
Your intervention in practice
Before the operation, you will be given precise instructions concerning skin preparation (shower to be taken), any medication to be stopped and fasting periods to be respected. These instructions will be given to you during the pre-anaesthetic consultation. As far as hospitalization is concerned, this surgery is generally performed on an outpatient basis, except in the event of a medical problem requiring a short hospital stay. After the operation, it is essential to have someone to accompany you home. The length of time you will be off work will depend on your occupation and your daily activities. It is advisable to suspend all sporting activities involving the operated joint for about a month.
