Synovial Cysts Article #2

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Synovial Cysts in the Spine Article #2

For patients with degenerative spinal conditions, one cause of their back pain may be synovial cysts. Synovial cysts are benign, fluid-filled sacs that develop in the facet joints of the lumbar spine as a result of degeneration. If large enough, these sacs can cause spinal stenosis - a narrowing of the spinal canal that places pressure on spinal nerves and causes pain. What causes synovial cysts? The synovium is a thin film of tissue that produces fluid to help lubricate the joints. When facet joints in the lumbar spine begin to degenerate, this fluid may build up in an attempt to protect the joint. In some patients, small amounts of the fluid escape from the joint capsule but remain within the synovium, creating a sac-like protrusion. These cysts are not under tremendous pressure and, even if quite large, rarely cause neurological problems or cauda equina (loss of bowel or bladder function).

Many older patients have synovial cysts in their lumbar spines but have no symptoms. Occasionally, however these cysts can cause pain in the lower back that travels down the legs. The pain is relieved when sitting as this position widens the spinal canal and relieves pressure on the nerves. How are synovial cysts diagnosed? A synovial cyst can be seen on a MRI. X-rays should also be done to determine the extent of the degeneration of the facet joints and to assess any other spinal conditions that can cause instability such as spondylolisthesis (when one vertebra slips forward onto another). How are these cysts treated? If the cysts are not causing any symptoms, no treatment except observation is needed. If the patient is experiencing mild discomfort, it may be advisable to simply restrict those activities that are the most uncomfortable. Pain relief medications, injections, and other conservative pain relief options such as physical therapy or chiropractic may also be helpful in relieving pain. However, if the patient's pain is severe, chronic, and interferes with their daily living activities, surgery may be necessary.

Microdecompression techniques may be used to treat synovial cysts. These procedures can be done using minimally invasive techniques and have a relatively short recovery time. However, there is the possibility that the cysts can re-form. Another option is to remove the cyst and fuse the joint in order to assure the cysts will not return. This is a more invasive procedure with a longer recovery time. Since every patient is different, a consultation with an experienced spine specialist is essential.

Synovial cyst, a fluid-filled para-articular mass lined by a synovial membrane, with or without communication with the neighbouring joint. Those that communicate commonly become distended with fluid and show an elevation in intra-articular pressure. Typical processes in which synovial cysts occur include rheumatoid arthritis, the seronegative spondyloarthropathy, osteoarthrosis and crystal deposition disease. Synovial cysts are encountered most commonly about the knee and hip, with the shoulder, elbow, wrist, foot, ankle and hand being involved to a lesser extent. Synovial cysts are of clinical significance because they may appear as a periarticular mass, cause pain or limitation of joint mobility, or compress adjacent neurovascular structures; they may also rupture acutely or dissect or become infected secondarily.

In the , any inflammatory, degenerative, traumatic or neoplastic condition that produces a knee effusion can lead to synovial cyst formation. The most characteristic location is the posterior aspect of the knee related to distension of the gastrocnemius – semimembranosus bursa in response to a knee effusion. These cysts are designated Bakers cysts or popliteal cysts and may dissect between the muscles of the leg or rupture with extravasation of fluid, producing clinical manifestations resembling those of thrombophlebitis. Ultrasonography, radionuclide arthrography, standard arthrography, CT, computed arthrotomography and MR imaging may be useful in the diagnosis of a Baker's cyst. MR imaging may provide the most detailed information regarding the distribution and extent of the process and the degree of synovial inflammation.

Rupture of a Baker's cyst is associated with soft tissue extravasation of fluid contents. Ruptures occurring posteriorly can simulate a compartment syndrome or thrombophlebitis. MR imaging is effective in demonstrating ruptured popliteal cysts. Typically a popliteal cyst is a well-defined mass of variable size with signal intensity characteristics of fluid. Changes in signal intensity characteristics may indicate haemorrhage or intrabursal osteocartilaginous bodies.

The arthrographic appearance of an abnormal synovial cyst varies. In most instances, a well-defined, lobulated structure filled with air and radiopaque contrast material will be revealed. It may have an irregular surface related to hypertrophy of its synovial lining. Alternatively, the entire cyst or a portion of it may rupture, with extravasation of contrast material.

In the hip, any process that leads to elevation of intra-articular pressure results in escape of fluid from the joint through a number of anatomic pathways and serves to decompress the joint. Typically, the fluid passes into a surrounding synovial sac which, with distension, can be seen or palpated. These synovial cysts can also be assessed with imaging methods, including ultrasonography, CT, arthrography, computed arthrotomography and MR imaging.

Synovial cysts are a well-known manifestation of rheumatoid arthritis. The cysts may arise as rupture of the joint capsule with extravasation of fluid and secondary encapsulation or as herniation of the synovial membrane, but usually they represent abnormal distension of various bursae that communicate with the adjacent joint. Rheumatoid synovial cysts have also been described at other sites, including the calf, the ankle, the plantar aspect of the foot, the hip, the hand and wrist, the elbow and the shoulder.

Synovial cysts may also develop in a degenerated apophyseal joint, most frequently at the L4 – L5 spinal level. Cysts that are medial to the ligamentum flavum appear as nearly round structures that displace epidural fat and may indent the dural sac. The capsule of the cyst is usually noticeably denser than the fluid contents and may be calcified. In some cases the fluid in the cyst is replaced with gas.

Intraspinal synovial cysts are more common in women, with 90% of lesions occurring in the lumbar region, predominantly at the L4 – L5 level. Clinical manifestations include motor and sensory deficits and reflex changes. The vast majority of such cysts arise adjacent to apophyseal joints with which they commonly communicate, and these joints are frequently involved with osteoarthritis. Routine radiography in cases of intraspinal synovial cysts shows nonspecific findings. Myelography may also reveal nonspecific findings. CT typically shows a soft tissue mass adjacent to a degenerative apophyseal joint; the mass may contain gas or possess a partially or completely calcified rim. The MR imaging findings of intraspinal synovial cysts include a mass lesion with variable signal intensity, signal void related to the presence of gas, and degenerative changes with fluid or gas collections in the apophyseal joints.

Love & God Bless! /Wolf~President I'm diagonally parked in a parallel universe. "Therefore encourage one another and build each other up, just as in fact you are doing."

1 Thessalonians 5:11

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Thank you for sending me this information - I am printing it off and will be reading it in bed later (Hubby works 3rd shift tonight - I'm not complaining - doubletime pay!).

Synovial Cysts Article #2