Long-Term Effectiveness of Direct CT-Guided Aspiration and Fenestration of Symptomatic Lumbar Facet Synovial Cysts

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Fig 1.
Successful CT-guided cyst puncture, aspiration, and fenestration. A, Axial T2-weighted MR image demonstrates bilateral L4–5 facet synovitis and a thin-rimmed T2-hyperintense cyst arising from the left L4–5 facet joint. B, Intraprocedural CT image shows contrast opacification of the cyst via injection into a 22-ga spinal needle placed within the left L4–5 facet joint (step 1). A second 22-ga spinal needle has been advanced coaxially into the cyst via a translaminar approach (step 2). C, CT image obtained after cyst aspiration and repeat fenestration demonstrates successful cyst perforation with leakage of contrast into the epidural space (arrow, step 3). D, Follow-up MR imaging shows resolution of the treated cyst.
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Fig 2.
Calcified synovial cysts. A, Axial T2-weighted MR image shows severe bilateral L5–S1 facet arthrosis with thick-rimmed facet cysts (arrows), which result in severe lateral recess narrowing on the right and indentation of the thecal sac on the left. B, Axial CT image shows peripheral calcification of both cysts (arrows). Direct cyst puncture and fenestration were not performed in this patient, who instead underwent CT-guided facet injections and nerve blocks and ultimately required an operation.

Table 1:

Demographic data

Table 2:

Differences in imaging characteristics of cysts between responders and nonresponders

	Responders	Nonresponders	P Value
LFSC size (mean) (SD) (mm)	10.1 (3.7)	9.3 (2.5)	.62^{^a}
Cyst level (No.) (%)			.66^{^b}
L1–L2	1 (2)	0 (0)
L2–L3	3 (5)	1 (17)
L3–L4	6 (10)	1 (17)
L4–L5	35 (60)	2 (33)
L5–S1	13 (22)	2 (33)
MRI central canal stenosis (No.) (%)			.70^{^b}
None	19 (33)	2 (33)
Mild	9 (15)	0 (0)
Moderate	11 (19)	1 (17)
Severe	19 (33)	3 (50)
MRI signal intensity (No.) (%)			.011^{^b}
High T2 with a thin rim	39 (72)	1 (17)
High T2 with a thick rim	13 (24)	5 (83)
Low T2	2 (4)	0 (0)
CT characteristics (No.) (%)			.027^{^b}
Calcified	14 (24)	4 (67)
Not calcified	44 (76)	2 (33)

Table 3:

Differences in imaging characteristics of cysts between patients who required surgery and those who did not at long-term follow-up