Ganglion Cyst 

Tumors of the hand are found to be benign 95% of the time when excluding a cutaneous malignancy.^[1] Representing about 60% of these benign tumors is the ganglion cyst.^[2] While a definitive etiology is unknown, the theory that the ganglion is the degeneration of the mucoid connective tissue, specifically collagen, has dominated since 1893, when Ledderhose described it as such.^[3] Nonsurgical treatment, arthroscopic surgery, and open surgery have all been used to treat the ganglion cyst, with arthroscopy leading the way with some promising results, especially in reducing the incidence of recurrence of dorsal ganglion cysts.^[4]

Recent studies

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. 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.^[5]

Rocchi et al compared 2 forms of treatment of volar wrist ganglia: open excision via longitudinal volar skin incision and arthroscopic resection through 2 or 3 dorsal ports. 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.^[6]

Multiple nonsurgical modalities have been used over the years for ganglion cyst, including simple aspiration. Surgery often becomes necessary, and recent findings suggest that arthroscopic ganglion excision is a practical and successful means of dorsal ganglion cyst removal.^{[4, 5, 6, 7]}

The problems that ganglion cysts present can be varied and are due to their location. Most often, the cyst will present at the dorsal wrist, accounting for 60-70% of all hand and wrist ganglia^[4] , and arise from the scapholunate joint.^[8] A ganglion cyst can also arise from the radioscaphoid or scaphotrapezial joint volarly.^[8] These locations can cause joint instability, weakness, and limitation of motion.^[8]

Compression of the median nerve can occur when a volar radial ganglion arises within the carpal canal.^[8] The ulnar nerve may also be compressed within the tunnel of Guyon when the ganglion presents on the ulnar side of the wrist. The patient can experience paresthesias and pain from a ganglion cyst, and in such cases, surgical treatment should be considered, to provide a favorable outcome with few complications.

Frequency

Ganglion cysts are the most common soft-tissue tumors of the hand and wrist. Although anyone can be affected by ganglion cysts, they occur 3 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 and are rare in children.^[2]

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]

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, while 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]

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. They can also occur in the flexor tendon sheaths, and when located at the DIP joints, they are termed mucous cysts^{[2, 8]} 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^[9] ; 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]

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] while pain, limitation of movement, and nerve palsies are indications for surgical excision.^[2]

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]

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.