How Serious Is a Cyst on Your Spine?

A cyst on the spine is a fluid-filled sac, not a tumor, and most are benign. Many are found by chance on a scan done for something else and never cause trouble.¹ How serious one is depends less on the cyst itself than on whether it crowds a nerve, so the same kind of cyst can be harmless in one person and the cause of real pain in another.

The Main Kinds of Spinal Cysts

Facet cysts grow from the small joints at the back of the spine, usually in the lower back.² They form where joints are worn, arthritic, or slipping out of line.³ That makes them mostly a condition of later life, and the chance of having one rises with each decade of age.⁴

Tarlov cysts form on the coverings of nerve roots, most often in the sacrum at the base of the spine.⁵ Spinal fluid can seep in through a tiny opening that lets fluid in more easily than out, so some slowly grow.⁶

Other types are uncommon. Arachnoid cysts form in a membrane around the spinal cord and are rare, mostly in the neck or mid-back.⁷ They can be present from birth or follow injury, inflammation, or past surgery.⁸ Dermoid and epidermoid cysts are rare and present from birth, often found in children and young adults.⁹¹⁰ Discal cysts grow next to a spinal disc.¹¹ Ask your doctor which type it is, because the options and risks differ between a facet cyst and a Tarlov cyst.

These cysts are not cancer. MRI can usually tell a true cyst from a tumor, blood, or fat, and the rare cyst with a solid lump inside gets a closer look to rule out a tumor.

How Often a Cyst Causes No Trouble

About 6.5 in 100 people having low-back imaging have a facet cyst.¹² Nearly half of those cysts cause no symptoms.¹³ Tarlov cysts turn up the same way: on low-back MRIs done for disc problems, about 2 in 100 people had one that was not the reason for the scan.¹⁴

Where your pain is offers one clue to whether a cyst matters, alongside the scan and an exam. It is a likely cause when your pain follows the path of the nerve it sits beside, such as leg pain on the same side as a low-back facet cyst. If your pain is on the right and the cyst is on the left, the cyst is less likely to explain it, and your doctor will look elsewhere.

Larger facet cysts are more likely to press on a nerve and cause leg pain.¹⁵ So are cysts on the front side of the joint, closer to the nerve roots.¹⁶ Ask whether your cyst is large or touching a nerve, since that shapes whether it explains your symptoms.

A harmless cyst usually needs no treatment. Doctors may suggest watching for new symptoms rather than repeating scans, and some facet cysts shrink on their own over time.¹⁷

Symptoms When a Cyst Presses on a Nerve

Pain can shoot along the nerve; in the leg it is felt as sciatica. Most people needing surgery for facet cysts had low back pain, leg nerve pain, and leg pain or heaviness when walking that eased with rest.¹⁸ The cyst narrows the space for nerves, much like spinal stenosis.

Facet cyst pain often changes with position. It tends to worsen with standing or walking and ease with rest or bending forward, because posture changes how much room the nerve has. A simple log of when pain hits, what you were doing, and what eased it helps your doctor link symptoms to the cyst.

Tarlov cysts cause a different pattern. One that presses on or pulls a nerve can cause nerve pain, numbness, weakness, sexual problems, and bladder trouble.¹⁹ The pain often spreads over several areas at once, including the pelvis, perineum, and both legs.²⁰ If you have a Tarlov cyst, pain that is hard to pin down and centered low in the pelvis may be worth raising with your doctor. Cysts in the neck are uncommon but can cause arm pain, tingling, and trouble with hand use or balance.²¹

Some changes can mean nerve pressure is getting worse: growing numbness or a patch of skin that feels dead, weakness such as tripping or a foot that slaps the ground, or pain that no longer eases with rest. These call for a prompt appointment rather than waiting for the next routine visit.

When a Spinal Cyst Becomes an Emergency

Cauda equina syndrome is pressure on the bundle of nerves at the bottom of the spine that control the legs, bladder, and bowel.²² It is usually caused by a disc, but a facet cyst that suddenly enlarges can cause it too.²³ In one reported case, an older woman had back pain and foot weakness for a week, then developed numbness around the groin and could not pass urine.²⁴ Emergency surgery removed a bleeding cyst and she recovered fully.²⁵

Go to the emergency room for any of these:

Numbness in the groin, buttocks, or inner thighs, the “saddle” area that would touch a saddle
New trouble passing urine, or leaking urine or stool, which suggests the nerves controlling the bladder and bowel are affected
Sudden weakness in one or both legs, especially alongside the other signs

Do not wait for a scheduled appointment. Say you have a known spinal cyst so staff can look for nerve compression quickly.

Treatments That Do Not Involve Surgery

First steps include anti-inflammatory medicine, gentle physical therapy, and steroid injections for temporary relief.²⁶ In reported cases, rest and physical therapy were followed by the cyst shrinking and symptoms easing enough to cancel planned surgery.²⁷²⁸

When there is no weakness, many doctors give this approach several weeks to a few months. Worsening weakness or bladder signs end the trial early, because waiting then risks nerve damage. Ask your doctor what milestone would mean moving to the next step, so the plan has a clear decision point.

A doctor can also put a needle into the cyst under scan guidance to drain it.²⁹ The visit is done awake, with numbing medicine and live imaging to guide the needle. It usually takes under an hour and you go home the same day. Relief can be immediate if fluid comes out, but the cyst can refill.

Drainage often fails for low-back facet cysts, which are usually thick and jelly-like; it doesn’t work in half or more of cases.³⁰ It can work well elsewhere. In one neck cyst, drainage plus a steroid injection gave relief still lasting four years.³¹ Discal cysts drained this way mostly did very well, though one came back and needed surgery.³²

Surgery and How Well It Works

Surgery is usually considered when a cyst causes weakness, when conservative care has not helped after a fair trial, or in an emergency.

Removing a facet cyst and freeing the nerve relieves back pain and leg pain in about 92 of every 100 people.³³ Some people also need the joint fused if it is unstable.³⁴ Keyhole endoscopic surgery gives results similar to open surgery.³⁵ After endoscopic removal, leg pain scores fell from about 8 to about 2 out of 10, and the share able to walk without limit rose from 1 in 3 to 8 in 10.³⁶ People whose joints looked unstable on MRI did less well.³⁷

Leg pain often eases soon after the nerve is freed. Numbness and weakness recover more slowly, sometimes over months. Most people return to light activity in weeks, and it takes longer after a fusion.

Arachnoid cysts causing major weakness usually need surgery soon, opening or removing the cyst wall.³⁸ About 8 in 10 people having surgery for symptomatic Tarlov cysts reported a better quality of life within a year,³⁹ and their pain at rest fell roughly by half.⁴⁰

A few questions are worth bringing to a surgeon:

Is my joint unstable, and will I need a fusion? That changes the operation and the recovery.
Can this be done endoscopically, through a smaller cut?
How many of these operations do you do? Experience with the procedure matters.
What results should I expect for leg pain versus back pain? Leg pain usually improves more reliably.

Risks of Surgery and Chances of the Cyst Returning

When surgery opens the membrane around the nerves, as with some arachnoid and Tarlov cysts, spinal fluid leaks happen in about 8 in 100 people.⁴¹ A leak makes wound healing problems and infection much more likely.⁴² Facet cyst surgery usually stays outside this membrane. After any such operation, call your surgeon promptly if you notice clear fluid from the wound, a headache that worsens when sitting or standing and eases lying flat, or a soft swelling under the scar.

Cysts can return after drainage or even after surgical removal.⁴³ Dermoid and epidermoid cysts came back in about 1 in 9 people after surgery.⁴⁴ In children with arachnoid cysts, about 9 in 10 were cured or improved, and one needed a drain tube after repeated return.⁴⁵

For facet cysts, recurrence ties to an unstable or worn joint. Core strengthening in physical therapy supports the spine, and it is worth asking about follow-up if your symptoms come back on the same side.

Spinal Cysts in Children

More than half of dermoid and epidermoid cysts are found before age 20.⁴⁶ Bladder problems and pain are the most common signs.⁴⁷ In children with arachnoid cysts, pain, leg weakness, and unsteady walking were common.⁴⁸ Rarely a cyst shifts and causes leg weakness that comes and goes.⁴⁹

Parents can watch for a few things. New bedwetting or bladder accidents in a child who was already toilet trained can point to nerve involvement. A change in walking, tripping, or a stiff leg is another sign. A dimple, tuft of hair, or patch of different skin on the low back can hint at a birth defect of the spine. Mention these to the pediatrician instead of waiting, since early evaluation is easy and reassuring when the cause is minor.

Outcomes after surgery are good. After surgery for dermoid and epidermoid cysts, about 8 in 10 regained feeling and about 7 in 10 regained normal bowel function.⁵⁰ Children with arachnoid cysts had no lasting nerve damage from surgery.⁵¹

1
PubMed. Incidental findings of the lumbar spine at MRI during herniated intervertebral disk disease evaluation ↩︎
2
Matthew Colman, MD. Spinal Cysts ↩︎
3
PubMed Central. Spinal lumbar synovial cysts. Diagnosis and management challenge ↩︎
4
PubMed. The Prevalence of Incidental and Symptomatic Lumbar Synovial Facet Cysts ↩︎
5
Matthew Colman, MD. Spinal Cysts ↩︎
6
PubMed Central. Management of Tarlov cysts: an uncommon but potentially serious spinal column disease—review of the literature and experience with over 1000 referrals ↩︎
7
PubMed Central. A Comprehensive Review of Arachnoid Cysts ↩︎
8
PubMed Central. A Comprehensive Review of Arachnoid Cysts ↩︎
9
Matthew Colman, MD. Spinal Cysts ↩︎
10
PubMed Central. Spinal Dermoid and Epidermoid Cyst: An Institutional Experience and Clinical Insight into the Neural Tube Closure Models ↩︎
11
PubMed Central. Degenerative intraspinal cyst of the cervical spine ↩︎
12
PubMed. The Prevalence of Incidental and Symptomatic Lumbar Synovial Facet Cysts ↩︎
13
PubMed. The Prevalence of Incidental and Symptomatic Lumbar Synovial Facet Cysts ↩︎
14
PubMed. Incidental findings of the lumbar spine at MRI during herniated intervertebral disk disease evaluation ↩︎
15
PubMed. The Prevalence of Incidental and Symptomatic Lumbar Synovial Facet Cysts ↩︎
16
PubMed. The Prevalence of Incidental and Symptomatic Lumbar Synovial Facet Cysts ↩︎
17
Neurochirurgie. Resolution of a synovial cyst of the lumbar spine without surgical therapy — A case report ↩︎
18
PubMed. Lumbar laminectomy for the resection of synovial cysts and coexisting lumbar spinal stenosis or degenerative spondylolisthesis: an outcome study ↩︎
19
PubMed Central. Clinical Experience of Symptomatic Sacral Perineural Cyst ↩︎
20
International Journal of Physical Medicine & Rehabilitation. Electromyography and A Review of the Literature Provide Insights into the Role of Sacral Perineural Cysts in Unexplained Chronic Pelvic, Perineal and Leg Pain Syndromes ↩︎
21
PubMed Central. CT Guided Aspiration of a Cervical Synovial Cyst ↩︎
22
Pain Physician. Acute Cauda Equina Syndrome Secondary to a Lumbar Synovial Cyst ↩︎
23
Pain Physician. Acute Cauda Equina Syndrome Secondary to a Lumbar Synovial Cyst ↩︎
24
PubMed. Facet joint cyst haematoma: a rare cause of cauda equina syndrome ↩︎
25
PubMed. Facet joint cyst haematoma: a rare cause of cauda equina syndrome ↩︎
26
NewYork-Presbyterian. Synovial Cyst on the Spine: Diagnosis & Treatment ↩︎
27
PubMed Central. Spontaneous resolution of synovial lumbar cyst presented with severe symptoms: a case report ↩︎
28
Neurochirurgie. Resolution of a synovial cyst of the lumbar spine without surgical therapy — A case report ↩︎
29
NewYork-Presbyterian. Synovial Cyst on the Spine: Diagnosis & Treatment ↩︎
30
PubMed Central. The diagnosis and management of synovial cysts: Efficacy of surgery versus cyst aspiration ↩︎
31
PubMed Central. CT Guided Aspiration of a Cervical Synovial Cyst ↩︎
32
PubMed Central. Successful treatment of a symptomatic L5/S1 discal cyst by percutaneous CT-guided aspiration ↩︎
33
PubMed Central. The diagnosis and management of synovial cysts: Efficacy of surgery versus cyst aspiration ↩︎
34
PubMed Central. The diagnosis and management of synovial cysts: Efficacy of surgery versus cyst aspiration ↩︎
35
PubMed. Full-Endoscopic Removal of Lumbar Juxtafacet Cysts: A Prospective Multicentric Study ↩︎
36
PubMed Central. Clinical outcomes with endoscopic resection of lumbar extradural cysts ↩︎
37
PubMed Central. Clinical outcomes with endoscopic resection of lumbar extradural cysts ↩︎
38
PubMed Central. Review/Perspective On the Diagnosis and Surgical Management of Spinal Arachnoid Cysts ↩︎
39
PubMed. Surgical Intervention is Associated with Improvement in Health-Related Quality of Life Outcomes in Patients with Symptomatic Sacral Tarlov Cysts: Results from a Prospective Longitudinal Cohort Study ↩︎
40
PubMed. Health-Related Quality-of-Life Outcomes in Surgical Patients With Sacral Tarlov Cysts: A 2-Year Prospective Study ↩︎
41
PubMed. Risk Factors for Postoperative Cerebrospinal Fluid Leakage After Intradural Spine Surgery ↩︎
42
PubMed. Risk Factors for Postoperative Cerebrospinal Fluid Leakage After Intradural Spine Surgery ↩︎
43
PubMed Central. Successful treatment of a symptomatic L5/S1 discal cyst by percutaneous CT-guided aspiration ↩︎
44
PubMed Central. Spinal Dermoid and Epidermoid Cyst: An Institutional Experience and Clinical Insight into the Neural Tube Closure Models ↩︎
45
PubMed. Spinal arachnoid cysts in the pediatric population: report of 31 cases and a review of the literature ↩︎
46
PubMed Central. Spinal Dermoid and Epidermoid Cyst: An Institutional Experience and Clinical Insight into the Neural Tube Closure Models ↩︎
47
PubMed Central. Spinal Dermoid and Epidermoid Cyst: An Institutional Experience and Clinical Insight into the Neural Tube Closure Models ↩︎
48
PubMed. Spinal arachnoid cysts in the pediatric population: report of 31 cases and a review of the literature ↩︎
49
PubMed. Mobile spinal enterogenous cyst resulting in intermittent paraplegia in a child: case report ↩︎
50
PubMed Central. Spinal Dermoid and Epidermoid Cyst: An Institutional Experience and Clinical Insight into the Neural Tube Closure Models ↩︎
51
PubMed. Spinal arachnoid cysts in the pediatric population: report of 31 cases and a review of the literature ↩︎