Ultrasound guided ganglion cyst aspiration and steroid injection

What is a ganglion cyst?

Ganglion cysts are thin-walled fluid-filled sacs commonly seen near the wrist joint but can also occur in other areas, such as the ankle and feet. These cysts typically form near joints or tendons as they originate from the joint or the tendon sheath (the tendon covering). The exact cause of ganglion cysts is not certain, but they are thought to be related to degenerative changes in the joint or tendon that lead to the overproduction of fluid, resulting in the formation of these cysts. The fluid within the cyst is typically thick and jelly-like.

How do I know if I have a ganglion cyst?

The main symptom of a ganglion cyst is the presence of a lump around the wrist or the ankle.

Can a ganglion cyst cause pain?

A ganglion cyst is generally not painful, but occasionally it can be uncomfortable and feel firm to the touch.

The size of the lump may vary, appearing larger or smaller on different days and sometimes disappearing altogether.

A ganglion cyst can cause pressure upon adjacent structures if large enough. It can result in pain or numbness if it is causing pressure upon a nerve within the wrist.

What other conditions can mimic a ganglion cyst?

The most frequently occurring lump around the wrist joint is a ganglion cyst. Other causes of swelling or lumps include fatty lumps such as lipomas, lumps from tendons like giant cell tumours, or nerves like nerve sheath tumours. Ultrasound can diagnose a ganglion cyst and rule out other conditions.

How to diagnose a ganglion cyst?

Ultrasound is the imaging modality of choice for assessing soft tissue lumps. It can accurately diagnose ganglion cysts, determine their size, and identify adjacent critical structures like nerves and vessels.

Are ganglion cysts dangerous?

No, ganglion cysts are not sinister. However, they can be uncomfortable and visually unappealing if they grow to a large size. It is essential to undergo an ultrasound assessment to confirm the diagnosis and eliminate other possible causes of lumps around the wrist.

What is the treatment for ganglion cysts?

Not all ganglion cysts require treatment. Treatment is only indicated if the appearance of the cyst is causing concern or if it is causing pain or discomfort for the patient. An old, traditional treatment method for ganglion cysts involves hitting them with a hard book, like the Bible. Although this might result in cyst rupture, It can cause significant harm to the soft tissues and bones in the wrist. Therefore, this is not recommended as a safe or effective treatment.

Ultrasound-guided ganglion cyst aspiration and steroid injection

Aspiration of the cyst under ultrasound guidance is an option. A large needle is used as the fluid is usually thick and gelatinous. The procedure is more successful with larger cysts. It is important to know that there is a high possibility of cyst recurrence after aspiration, estimated at around 50%. Injecting a small dose of steroid after the aspiration aims to reduce the inflammation in the area and reduce the chance of ganglion cyst recurrence, but this remains a possibility. Using ultrasound guidance will ensure accurate needle placement and avoid injuring important structures adjacent to the ganglion cyst. Surgical treatment can be considered for persistent cysts despite ultrasound-guided aspiration and steroid injection.

How is ganglion cyst aspiration done?

Your doctor will speak to you on the day about the procedure and address your questions. The procedure is done under ultrasound guidance, and you will be positioned according to the site of the cyst. The doctor will assess the area using ultrasound to determine the best approach. Then the skin will be cleaned and prepared at the injection site, and numbing medication can be administered to the skin using a small needle. Then, a needle will be advanced into the cyst under ultrasound guidance to allow for fluid aspiration and injection of steroids. Aspiration of small ganglion cysts can be unrewarding it can result in very little fluid (or no aspirate), but still, the wall of the cyst can be fenestrated a few times to reduce the possibility of fluid accumulation. Steroid injection helps reduce the inflammation in the area and the possibility of cyst recurrence.

What happens after the procedure?

A small plaster is usually applied to the site of the procedure. You can remove this later during the same day. You can eat and drink normally before and after the procedure. You can shower as usual but avoid very hot showers/steam rooms. You can use simple painkillers like paracetamol if you experience pain at the injection site. It’s advised not to drive immediately after the procedure. Rest the area and avoid extraneous activities for at least 48 hours after the procedure.

What are the possible complications of ganglion cyst aspiration/steroid injection?

The complications are very rare in general. These include:

Pain and discomfort for a few days. This is sometimes referred to as a steroid flare.
Temporary bruising due to small blood collection under the skin at the injection site.
Infection. This is very rare but important to be aware of.
Possibility of injury to adjacent structures (like nerves or vessels). This is rare with ultrasound guidance.
Patients must be aware of the possibility of ganglion cyst recurrence after the procedure. A steroid injection would reduce the chance of this.
Patients must be aware that ganglion cysts (especially small ones) usually contain thick fluid that can be difficult to aspirate using a needle.
If you have diabetes, your blood sugar level may temporarily increase after a steroid injection.
If you have high blood pressure, your blood pressure may temporarily increase.
Local fat thinning or skin colour change at the injection site.

How long does the ganglion cyst aspiration procedure take?

The length of the procedure depends on the difficulty of the case and the doctor's experience. Usually, 30 minutes is a reasonable time for the whole procedure (including explanation to the patient and preparation).

How long do I need to rest after a ganglion cyst aspiration?

The recommended rest period after a ganglion cyst removal varies depending on the size and location of the cyst, as well as the type of activities involved. For large cysts in weight-bearing areas like the ankle, avoiding high-impact activities such as sports for around a week is advisable. For small ganglion cysts, the recommended rest period is shorter at approximately 48 hours, especially for low-impact activities such as office work.

Can a ganglion cyst go away?

Yes, ganglion cysts can disappear spontaneously without any treatment.

Can ganglion cysts happen in the foot?

The wrist, foot and ankle are the most common places for a ganglion cyst.

Can a ganglion cyst be surgically removed?

Yes, surgery is a treatment option for ganglion cysts.

Surgical treatment vs ganglion cyst aspiration

This is best discussed with a specialist hand surgeon. Overall, surgical treatment can remove the cyst, but still, there is a high chance of cyst recurrence (approaching 25%). Therefore, conservative treatment might be favoured, including ultrasound-guided aspiration and steroid injection.

How fast will a ganglion cyst come back after aspiration?

This is variable and difficult to predict. It ranges from days to weeks or months.

Does an X-ray show a ganglion cyst?

No. X-rays are good for assessing the bones but not the soft tissues. Ultrasound is the preferred imaging technique to establish the diagnosis and guide aspiration if indicated.