Sacral cyst

Introduction to fistula cyst The fistula cyst is a dural cyst that originates from the spinal capsule. Therefore, it is called "intraspinal meningeal cyst" to collectively refer to such diseases. There is no exact statistics on the incidence of fistula cysts in the population. Since the widespread use of MRI in clinical practice, the rate of discovery of fistula cysts has become higher and higher, causing great concern for patients. In fact, understanding the causes and treatment of fistula cysts can greatly reduce this concern. A fistula cyst is a type of meningeal cyst, which is roughly divided into two types: Nabors IB and Nabors II. Patients with epidural meningeal cysts that do not contain spinal nerve fibers are mostly asymptomatic, and 25% of patients with epidural meningeal cysts containing spinal nerve fibers have symptoms. The fistula has a sensory and motor nerve that governs the saddle area, the dorsal side of the thigh, and the perineal area, as well as parasympathetic nerve fibers that control the bowel movements. The cysts press the sciatic nerve near the head. Therefore, the clinical manifestations of fistula cysts are mainly chronic lower back, appendix, and perineal pain. It can also be accompanied by pain in the back of the thigh, sciatica, and even neurogenic claudication. The fistula cysts are common, most of them are asymptomatic, and generally do not need to be treated for asymptomatic patients. For patients with symptoms, active surgical treatment should be performed on the premise of exclusion of disc herniation, spinal stenosis or intraductal tumor. basic knowledge Sickness ratio: 0.001%-0.002% Susceptible people: no special people Mode of infection: non-infectious Complications: lumbar spondylosis

The cause of fistula cyst

Trauma factor (25%)

Trauma caused by various accidents or carrying heavy objects (especially the fistula), fatigue, excessive force, childbirth, epidural anesthesia, resulting in increased cerebrospinal fluid pressure, spinal fluid filled into the cyst, while the cyst becomes larger and oppresses the nerve Form a cyst.

Congenital factors (30%)

The fistula cyst is a dural cyst that originates from the spinal capsule. Therefore, it is called "intraspinal meningeal cyst" to collectively refer to such diseases. Most of the spinal canal cysts are considered congenital. For whatever reason, the formation of a cyst is always due to its initial communication with the subarachnoid space. The cerebrospinal fluid enters with the arterial pulsation and eventually expands due to poor outflow or due to hydrostatic pressure.

Bacterial infection (8%)

It has been reported in some countries that some patients are accompanied by an outbreak of herpes virus in the body, so it is also pointed out that viruses or bacteria may also be one of the causes of cysts.

Fistula cyst prevention

Because the cause of fistula cysts is not clear, there are no preventive measures at present, and early detection and early treatment are the key to prevention. However, it is also possible to pay attention to the following aspects to prevent the occurrence of diseases.

1. Take safety measures to prevent the spine from being damaged by external violence.

2, pay attention to the maintenance of the spine, such as weight-bearing should not be too heavy, so as not to induce spinal lesions.

3, do some exercise activities and exercise that are good for the spine.

Fistula cyst complications Complications lumbar spondylosis

As mentioned above, the fistula cyst is a meningeal cyst, not a tumor, and there is no possibility of malignancy. The cerebrospinal fluid pressure in the cyst is increased, and the surrounding phrenic nerve and bone are compressed. In severe cases, bone destruction can be caused. If the cyst continues to compress peripheral nerve fibers, severe patients may experience sensory, motor dysfunction, and even dysfunction of the bowel and bladder. A rare cyst rupture causes chemical inflammation.

Fistula cyst symptoms common symptoms sciatica lower back pain lumbosacral or lower back pain perineal traction pain

Patients with epidural meningeal cysts that do not contain spinal nerve fibers are mostly asymptomatic, and 25% of patients with epidural meningeal cysts containing spinal nerve fibers have symptoms. The fistula has a sensory and motor nerve that governs the saddle area, the dorsal side of the thigh, and the perineal area, as well as parasympathetic nerve fibers that control the bowel movements. The cysts press the sciatic nerve near the head. Therefore, the clinical manifestations of fistula cysts are mainly chronic lower back, appendix, and perineal pain. It can also be accompanied by pain in the back of the thigh, sciatica, and even neurogenic claudication. There are two types of clinical:

Nabors Type IB

Epidural meningeal cysts (Nabors type IB) that do not contain spinal nerve fibers, are arachnoid fistulas caused by congenital dural diverticulum or congenital dural defects, mostly at the S1-3 level of the fistula, common in adults There is no significant difference between men and women.

Nabors Type II

An epidural meningeal cyst containing spinal nerve fibers, also known as a Tarlov aortic cyst or a spinal nerve root diverticulum (Nabors II), forms a cyst for the abnormal expansion of the distal end of the spinal nerve root sleeve, generally at the S2-3 level. The spinal ganglia or its distal end are more common in adults.

Sacral cyst examination

X-ray examination

It can be found that the erosion of the tibia bone is mainly manifested by the expansion of the fistula, and the bone erosion at the posterior margin of the vertebral body is fan-like. Sometimes there are congenital malformations of the lumbosacral region such as recessive spina bifida, spondylolisthesis, and kyphosis.

CT examination

Bone destruction and space-occupying lesions can be clearly demonstrated, especially for the tibia.

MRI examination

It is the most reliable method for the diagnosis of spinal meningococcal cysts. The cysts are long-shaped sacs, oval and irregular. The cystic fluid signal is similar to the cerebrospinal fluid signal. TlWI is low signal and T2WI is high signal. Type IB is located in the fistula and is separated from the dural sac by fat. Type II is located lateral to the dural sac and there are nerve roots in the sac.

Diagnosis and differentiation of fistula cyst

diagnosis

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

Differential diagnosis

Lumbar disc herniation

Intraspinal meningeal cysts have a slow course, mild and atypical clinical symptoms, and clinical manifestations and signs have similarities with lumbar disc herniation. Characteristics of fistula cysts: cysts are benign lesions, slow growth, long course of disease, symptoms may have intermediate remission; symptoms are lumbosacral pain, perineal sensation hypothyroidism, chronic process; cysts are expansive lesions, spinal X-ray In the plain film, the spinal canal is enlarged, the pedicle is thinned, and the pedicle spacing is widened; MRI can be clearly identified.

Intraductal tumor

The tumors were mostly solid tumors, and the MRI enhanced scan showed tumor enhancement; the Tarlov cyst was located outside the epidural space of the ankle, and there were multiple cystic masses of different sizes, and MRI enhanced scanning cysts were not enhanced.

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