Ganglion Cyst

Dorsal ganglia most often affect the scapholunate joint, and the scaphoid interosseus ligament and extensor tendons must be considered because they are closely associated with the joint capsule. Volar ganglia are commonly associated with the radioscaphoid and scaphotrapezial joints, with proximity to the palmar cutaneous branch of the median nerve and the median nerve itself. Mucous cysts can be anatomically associated with the germinal matrix and are generally displaced lateral to the midline by the extensor tendon.[2]

Although ganglion cysts can be unilobulated, they are most often multilobulated, with septa made from connective tissue separating the lobes or cavities.[3] Thornburg points out that because there is no epithelial lining of the cyst wall, a ganglion cyst is not a true cyst and, because of this histologic observation, the theories of synovial herniation or synovial tumor formation are not supported and may be disputed.[2]

Hyaluronic acid predominates the mucopolysaccharides that make up the fluid within the cyst’s cavity, whereas collagen fibers and fibrocytes make up the wall lining.[3] The development of these cysts is histologically observable beginning with swollen collagen fibers and fibrocytes, followed by a degeneration and liquefaction of these elements, a termination of degeneration, and, lastly, a proliferation of the connective tissue, resulting in a border that is dense in texture.[3]

The etiology of the ganglion cyst has been described as an outpouching of synovium; as an irritation of articular tissue, creating a new formation; and, the most common and accepted theory, as a degeneration of connective tissue and cystic space formation.[3] It has also been suggested that degeneration of the connective tissue is caused by an irritation or chronic damage causing the mesenchymal cells or fibroblasts to produce mucin.[2]

Ganglion cysts are the most common soft-tissue tumors of the hand and wrist. Although anyone can be affected by ganglion cysts, they occur three times as often in women as they do in men. Mucous cysts are found in the distal interphalangeal (DIP) joint and generally present with osteoarthritis, and therefore, they are most commonly seen in older patients. Ganglion cysts are predominantly seen in young adults.[2] They are comparatively rare in children and thus have not been thoroughly studied in the pediatric population; when they do develop in children, they can often be effectively treated by surgical means.[11, 12]

Regardless of treatment, recurrence is possible, but the cause is unclear.

Rizzo et al performed a study of arthroscopic excision of dorsal wrist ganglia and found statistically significant increases in wrist extension and grip strength postoperatively, as compared to preoperative values.[10] Of the 41 patients in the study, 34 had no pain postoperatively, and seven had mild or occasional pain. Only two patients experienced recurrence, but the ganglia recurred again following a second removal using open excision, suggesting that the arthroscopic technique may not have been the cause of failure. Although some patients reported wrist stiffness after the surgery, motion was fully restored by 6 months for the last patient.

Edwards and Johansen prospectively evaluated outcomes of arthroscopic dorsal wrist ganglia resection and found that the patients experienced significant increased function and decreased pain within 6 weeks after arthroscopic resection; recurrence and complication rates appeared comparable to those of open resections.[8] Ganglion cysts also had a high association with certain interosseous laxities, and recurrent cysts originating from the midcarpal joint were not contraindications for arthroscopic resection. The authors noted that assessment of the midcarpal joint is necessary for complete resection of most ganglion cysts, and identification of a discrete stalk is an uncommon finding and is not necessary for successful resection.

Rocchi et al compared two forms of treatment of volar wrist ganglia: open excision via longitudinal volar skin incision and arthroscopic resection through two or three dorsal ports.[9] The results of the study suggested that arthroscopic resection is a reasonable alternative to open excision in treating radiocarpal volar ganglia, because it is associated with less postoperative morbidity and a better cosmetic result. Midcarpal volar ganglia, however, according to the authors, should still be treated by open removal.

Ganglion cysts can occur at any joint or tendon sheath, but they most often present in the dorsum of the wrist at the scapholunate joint, followed by the volar wrist. (See the images below.) They can also occur in the flexor tendon sheaths, and when located at the distal interphalangeal (DIP) joints, they are termed mucous cysts[2, 5] Of the dorsal wrist ganglia, 75% connect with the dorsal scapholunate interosseous ligament.[2] Many patients who have had asymptomatic cysts for months or even years can present with newly developed pain or limitation of activity.

The skin above the cyst is unchanged, but the mass itself is compressible and movable and transilluminates. Compression of the median nerve cutaneous branches may elicit a sensory or motor nerve palsy when a volar carpal ganglion is present[13] ; this is an indication for surgical removal.

A mucous cyst, at the DIP joint on the dorsum of the hand, will frequently be associated with osteoarthritis and may place pressure on the germinal matrix and cause malformation of the nail. Unlike with the ganglia of the wrist, mucous cysts can cause the overlying skin to become thinned and may even lead to skin rupture.[2] Patients presenting with mucous cysts may complain of pain; however, the cause of the pain is often the associated osteoarthritis rather than the cyst itself.[2]

Ganglion cysts can also be associated with a tendon and may be adherent to the tenosynovium; however, the presence of an extensor digitorum brevis manus muscle must be excluded. Ganglion cysts within bone, termed interosseous cysts, most often affect the scaphoid and lunate and require open surgery for removal; therefore, it is important to determine whether the cyst is the cause of the pain.[2]

Although a plain radiograph will provide visualization of the cyst, it can identify bony abnormalities that may be causing the symptoms or may contraindicate treatment. In older adults, degenerative joint disease may accompany the cyst at the scaphotrapeziotrapezoid joint and can be confirmed by the plain radiograph. Magnetic resonance imaging, ultrasonography, or arthroscopic imaging may prove useful in obtaining confirmation of clinical diagnostic findings.[2, 5, 14]

An Allen test should be performed when cysts are located near the radial artery, including most volar wrist ganglia. Ultrasonography is an inexpensive and noninvasive method of assessing the soft tissue.

Because the hand and wrist are very visible in day-to-day activity, aesthetics can be an indication for treatment but may favor a less invasive intervention,[3] whereas pain, limitation of movement, and nerve palsies are indications for surgical excision.[2]

There are few contraindications for ganglion excision. Caution is advised, however, for those few patients who have only one upper extremity and desire elective removal of a cyst. Any postoperative complication will create a substantially larger impact on such patients.

When the ganglion wall is thin, in the early stages, the cyst can be manually compressed until it bursts, and fluid is absorbed; this is the least invasive treatment.[3] A slightly more invasive approach, with a cure rate of 40%, is aspiration; cure rate is 85% when a minimum of three aspirations are performed.[2]

Corticosteroid injection with aspiration has been indicated by some authors,[5] but Thornburg[2] asserted that it has not proved beneficial and that it should be avoided in cases of mucous cysts because it can cause further thinning of overlying skin.[5] Although 70% of volar retinacular cysts are successfully treated with aspiration,[2] radial volar wrist ganglia are often in close contact with the radial artery and are therefore contraindicated for aspiration.[5]  Ultrasound-guided aspiration/injection appears to be safe and effective for symptomatic lower-extremity ganglion cysts.[15]

Another moderately invasive procedure is cyst puncture. Although it has a 95% cure rate, it is not widely used. In this treatment procedure, a suture is passed through the skin perpendicularly through the cyst and is left there for 3 weeks, increasing the risk of infection.[2]

Kim et al cited two case reports in which the application of electroacupuncture for 20 minutes once a week for 8 weeks reduced the size of the wrist ganglion on follow-up ultrasonography while also relieving the accompanying pain.[16]

Choice of operation

Open removal has been the surgical treatment of choice for ganglion cyst removal, with arthroscopy offering some benefits, including a reduction in intraoperative risks and postoperative complications. Recurrence is seen with all treatment modalities and has been reported to be as high as 40% following open excision of dorsal wrist ganglia.[4, 6]

Regardless of whether the ganglion is removed via open surgery or via arthroscopic excision, when a stalk is visualized, it should be completely removed, or the cyst should be removed at the origin to reduce the risk of recurrence. A recurrence rate of 13-40% has been observed following removal of entire cysts, but when a portion of the capsule is removed as well, recurrence rates decrease to as low as 4%.[2] Some surgeons close the capsule; however, this can lead to reduced, or loss of, wrist flexion, so most surgeons do not close the resulting defect.[2]

Brief splinting of 3-7 days is recommended for both open and arthroscopic ganglionectomy, but it seems that wrist motion within 3-5 days after the procedure can prevent stiffness.[2, 5, 10] A volar ganglion cyst is much more likely to recur than a dorsal ganglion cyst,[4] and care must be taken to protect the radial and ulnar neurovascular bundles because radial artery laceration is the most common vascular complication in volar carpal excision of ganglia.[2] (See the images below.)

Compared to an open ganglionectomy, arthroscopy uses smaller incisions and therefore leaves smaller scars; arthroscopy also allows better visualization and easier identification of other intra-articular pathologies, such as triangular fibrocartilage complex (TFCC) tears or ligament injuries.[4] The scapholunate interosseous ligament is of concern with open dorsal ganglionectomy, and the arthroscopic procedure provides protection of this ligament and allows for better control of excision.[10]

Although arthroscopic excision can be performed for radiocarpal volar ganglia, an open procedure is usually used.[9] When surgery is indicated for a mucous cyst, as it would be if there is nail deformity, pain, or skin thinning, it is important to also remove the osteophytes in an effort to significantly reduce the rate of recurrence.[2]

Procedure

A local block is not sufficient, and an intravenous regional or axillary block is recommended. Prior to an open procedure, an Allen test is performed to ensure collateral blood flow of radial and ulnar arteries.[2, 10] Thornburg also recommends the use of loupe magnification, a tourniquet, and bipolar cautery for open volar ganglionectomy. Because of the possibility of radial artery lacerations during volar carpal ganglion excision, careful protection and retraction of the radial artery are important for volar ganglionectomy following a careful dissection of the artery. If during dissection the cyst wall is not easily freed from the artery, it can be left and the remaining cyst and stalk removed.[2]

A distraction tower and 2.7-mm arthroscope are used for dorsal ganglion excision.[10] The 6R portal and 3-4 or 4-5 portals are most often used, whereas the 1-2 portal is rarely if ever used.[2, 10] In the Rizzo cohort, the average tourniquet time was 30 minutes, with one case of 18 minutes.[10] Aggressive excision, including removal of the stalk and even part of the joint capsule, is important in both surgical techniques for the wrist, but injury to ligaments needs to be avoided. Closure of the capsule is not recommended because of loss of wrist flexion.

A curved transverse incision, as well as T, H, and inverted U incisions, are all appropriate for mucous cyst removal; however, the H incision tends to provide the best visualization of osteophytes, which are recommended to be debrided along with cyst removal.[2] Because mucous cysts are intimately associated with the germinal matrix, care should be taken to avoid damaging this structure, which can extend 5 mm proximal to eponychial fold.[2]

For both open and arthroscopic wrist procedures, brief immobilization in slight extension for volar ganglion excision and slight flexion for dorsal ganglion excision,[5]  followed by early motion, provide the patient with comfort and prevent wrist stiffness.[2]  Following mucous cyst removal, immobilization is unnecessary unless debridement harmed the extensor tendon.[2]

In open and arthroscopic procedures, wrist stiffness is the most common postoperative complication; however, leaving the capsule open during an open procedure tends to reduce the risk of this complication, as does early motion.[2]  Neurovascular injury, especially radial artery laceration, is a possible complication, along with infection, decreased motion, and ligament instability in open excision—namely, of the scapholunate ligament.[2, 4]