Management of Perineural Cysts in the Thoracic Spine
For symptomatic thoracic perineural cysts that fail conservative management, microsurgical cyst fenestration or wrapping surgery should be performed, as these techniques provide safe and effective symptom relief with minimal complications.
Initial Diagnostic Workup
MRI of the thoracic spine without IV contrast is the imaging modality of choice for evaluating suspected perineural cysts causing radiculopathy or myelopathy 1. The imaging should assess:
- Cyst location, size, and number
- Degree of nerve root or spinal cord compression
- Presence of associated structural abnormalities 1
CT myelography may be complementary when MRI findings are equivocal or for presurgical planning, though it requires lumbar puncture for intrathecal contrast injection 1.
Conservative Management Approach
Initial conservative therapy should be attempted before considering surgery 2, 3. This includes:
- Oral corticosteroids for symptomatic relief, which may reduce inflammation around compressed nerve roots 2
- Epidural steroid injections as an alternative non-surgical option 2
- Observation with serial MRI at 6-month intervals to document cyst stability 4
Conservative management is appropriate for minimally symptomatic cysts without progressive neurological deficits 3. However, approximately 40% of conservatively managed patients may show symptom progression at long-term follow-up 3.
Indications for Surgical Intervention
Surgery should be considered when:
- Persistent radicular symptoms despite conservative therapy 5, 6, 3
- Progressive neurological deficits or myelopathy 1
- Severe intractable pain affecting quality of life 6, 7
- Bladder or bowel dysfunction 6, 7
A diagnostic cyst aspiration can help identify surgical candidates - patients showing clinical improvement after aspiration are more likely to benefit from definitive surgery 3. In one series, 24 of 28 patients (86%) who improved after aspiration were offered surgery 3.
Surgical Techniques
Microsurgical Cyst Fenestration
This is the most established surgical approach with demonstrated safety and efficacy 3. The technique involves:
- Partial laminectomy for exposure
- Opening and fenestrating the cyst wall
- Decompression of adjacent nerve roots 3
Success rates are excellent: 16 of 17 patients (94%) showed clinical improvement at long-term follow-up with no surgical complications 3.
Novel Wrapping Technique
For cysts causing compression of adjacent nerve roots, wrapping surgery offers an alternative 7. This involves:
- Cyst puncture and CSF aspiration to reduce size
- Dissection of compressed nerve roots from the cyst
- Wrapping with Gore-Tex membrane to prevent reexpansion 7
This technique achieved complete symptom relief in all 7 treated patients, with pain scores dropping from 7.9 to 0.6, and no recurrence during 39-90 months follow-up 7.
Vascularized Fasciocutaneous Flap Technique
For sacral cysts (less applicable to thoracic), cyst fenestration with pedicled vascularized flap successfully obliterated cysts in all cases, though clinical efficacy was more variable (4 of 7 patients improved) 6.
Surgical Excision
Complete surgical excision is curative for symptomatic thoracic perineural cysts 5. One case report demonstrated complete resolution of radicular symptoms after excision of a T1 nerve root perineural cyst that was initially mistaken for a nerve sheath tumor 5.
Follow-up Protocol
Postoperative monitoring should include:
- Clinical assessment of symptom improvement
- Repeat MRI to confirm cyst reduction and nerve root decompression 7
- Long-term surveillance for cyst recurrence (though rare with proper surgical technique) 7
Critical Pitfalls to Avoid
Do not perform surgery on asymptomatic or incidentally discovered cysts - these require only reassurance and do not warrant intervention 4.
Distinguish thoracic perineural cysts from nerve sheath tumors on imaging, as they can appear similar but require different management 5.
Avoid prolonged conservative management in patients with progressive neurological deficits - early surgical intervention prevents irreversible nerve damage 1, 3.
Be aware that traditional surgical approaches carry risks of postoperative pseudomeningocele, intracranial hypotension, and cyst recurrence, making proper surgical technique selection critical 2.