1. David Pastel, MD, Steffen Haider, MD, Nu NA, BSc, Mohsin Ghadiali, md
Symptomatic lumbar facet synovial cysts: Clinical outcomes following percutaneous CT-guided cyst rupture with intra-articular steroid injection
Poster # 195
David Pastel, MD, Steffen Haider, MD, Nu NA, BSc, Mohsin Ghadiali, md

2. Disclosures
None

3. Purpose
Prospectively evaluate clinical outcomes following percutaneous rupture of symptomatic lumbar face synovial cysts (LFSC) with intra- articular steroid injection.

4. Background
Synovial cysts arising from the lumbar spine facet joints are most commonly seen in the setting of degenerative spondylosis of the facet joints (1-6).
The incidence of lumbar facet synovial cysts (LFSC) detected by imaging ranges from 0.8% to 2.0% (7).
LFSCs most frequently involve the L4-L5 level, the site of maximum spinal instability (Assam, Gorey, Onofrio, Sabo).

5. Background
Clinical diagnosis is best achieved by MRI because of its superior contrast resolution (Davis, Imai, Hemminghytt, Jackson, Liu, Yuh, Marichal, Tillich, Mahallati).
Typically LFSC are T2 hyperintense, but the signal intensity is variable and can affect outcomes.
Cambron et al reported improved outcomes with T2 hyperintense cysts relative to intermediate and low signal intensity cysts. (Cambron et al AJNR 2013).

6. Background
LFSC that project into the spinal canal can cause radiculopathy (87%), neurogenic claudication (44%), sensory loss (43%) and motor weakness (27%) (8).
Surgical resection, with or without concomitant fusion, and percutaneous rupture have been described as treatment modalities for this disease.
Percutaneous rupture of LFSCs are most commonly performed indirectly via the facet joint using fluoroscopic or CT-guidance.

7. Methods
44 patients with symptomatic lumbar facet synovial cysts (LFSCs) receiving attempted CT-guided synovial cyst rupture with intra- articular steroid injection as primary treatment were prospectively reviewed.
Inclusion criteria consisted of lower extremity radiculopathy corresponding to the location of a LFSC on a lumbar spine MRI performed at least 2 months prior to percutaneous rupture.

8. Methods
Numeric pain scores, pain medication use, and Oswestry Disability Index (ODI) and SF-12 questionnaires were collected pre-procedure and after 1 week, 1 month, 6 months, and 1 year following the procedure.
Previous surgical history, technical success of cyst rupture and need for subsequent surgery or lumbar epidural steroid injection were recorded.

9. Baseline Patient Characteristics
Total Patients undergoing cyst rupture 44
Male
43% (n=19)
Mean Age
65 years (SD 12, range 43 to 94)
BMI
Obese (BMI > 30)
28 (SD 7)
30% (n=13)
Any Prior lumbar procedure
Lumbar epidural spinal injection
Lumbar Surgery
LFSC rupture
32% (n= 14)
25% (n=11)
7% (n=3)
5% (n=2)
Self-reported Daily Pain medication (Pre-procedure)
Opiate
Non-opiate pain medication
No daily pain medication
70% (n=31)
16% (n=7)
54% (n=24)
31% (n=13)
Cyst Level
L2/3
L3/4
L4/5
L5/S1
Multi-level
2%, (n=1)
18%, (n=8)
61%, (n=27)
16%, (n=7)
Cyst diameter
9.2mm (SD 3.4, N=24)

10. Table 2 Cyst rupture Outcomes
Technically Successful Cyst Ruptures
84% ( 37 / 44)
Repeat cyst rupture
7% (3 / 44)
Lumbar epidural spinal injection within 1 year
25% (11 / 44)
Lumbar Surgery within 1 year after rupture
Mean time to surgery if required
128 days (SD 76)

11. Procedure Methodology
Moderate sedation was administered and 1% lidocaine buffered with sodium bicarbonate was used for local anesthesia.
A 20-ga spinal needle was then advanced under intermittent CT fluoroscopy into the facet joint and 1–2mL of Omnipaque 350) diluted in normal saline at a ratio of 1:10 was injected to confirm continuity of the facet joint with the synovial cyst.
In patients with osteophytes covering the facet joint, a 14-ga coaxial system was used to access the facet joint.

12. Procedure Methodology
Once the cyst was opacified with contrast, a high-pressure syringe was used to rupture the cyst into the epidural space by use of dilute contrast.
A technically successful cyst rupture was determined by the loss of resistance method and by extravasation of contrast outside the confines of the cyst wall on CT.
After cyst rupture, 80 mg of methylprednisolone was injected into the facet joint.
Patients were observed for 1 hour after the procedure.

13. Results
Percutaneous LFSC rupture was technically successful in 84% of cases, with failure associated with previous lumbar procedures and surgery.
25% required surgery within 1 year which did not correlate with technical success of cyst rupture (p=1.0).
Three LFSCs that recurred after an initial successful rupture were successfully managed with repeat rupture.

14. Table 3: Outcomes over time series by General Linear Mixed Model
Worst Numeric Pain
ODI
SF 12 PCS
SF 12 MCS
Time
Mean (95% CI) P p
Pre
8.5 (7.7 , 9.4)
.000
34 (28 , 40)
.011
30 (27 , 34)
52 (47 , 56)
.643
One week
3.6 (2.6 , 4.5)
.259
12 (6 , 18)
.045
45 (41 , 49)
.111
58 (56 , 60)
.010
One month
4.7 (3.6 , 5.9)
.738
18 (12 , 24)
.443
40 (36 , 45)
.800
51 (47 , 55)
.455
Six month
4.5 (3.3 , 5.7)
.962
21 (15 , 28)
.974
38 (33 , 42)
.188
53 (48 , 57)
.908
One year
4.5 (3 , 6)
ref
21 (12 , 31)
41 (36 , 46)
53 (49 , 57)
**p-values correspond to differences in scores compared to the reference 1 score, i.e., significant differences in pain or function compared to the study end-point.
Models include covariate effect modifiers listed in Table 4
Scores obtained after a patient progressed to surgery were excluded.

15. Results
Numeric pain scores, ODI, and SF12 physical composite scores all demonstrated significant improvement all time points.
At 1 year follow-up, numeric pain scores decreased from 8.5 to 4.5 (p<0.001), ODI improved from 34 to 21 (p=0.011) and SF12 PCS improved from 30 to 41 (p<0.001).
SF12 mental composite score significantly improved at 1 week (52 to 58, p=0.010), but was not significant at any other time point.

20. Results
A history of previous lumbar spine intervention was associated with a higher combined post-procedure numeric pain score (+2) and a higher combined post-procedure ODI score (+17) compared to those without prior lumbar procedures (p=.014 and <.001 respectively).
There was a trend towards worse SF12 PCS scores (p=.085) in this subgroup, but no difference in MCS scores (p=..244).

21. Results
Obesity was associated with a higher combined post-procedure pain score (+2.2) when accounting for baseline differences (p=0.01), but no difference in ODI and SF12 PCS MCS scores p= .722, .258, .373).
Rupture success had no impact upon any outcome scores (p=.24 to .59) when accounting for baseline differences, although this was the smallest sub-group with only 7 patients.

22. Results
LESIs were performed upon 25% of patients within the year after LFSC rupture and was not associated with any measured patient characteristics, including progression to lumbar surgery (p=0.406) or prior lumbar procedures (p=0.722).
Patients undergoing LESI within one year after LFSC rupture had similar pre-procedure pain and function to those that did not (p=0.52 and 0.97), but reported worse combined post-procedure pain scores(+2.9, p=.001), ODI (+11, p=.014), and SF12 MCS (-7, p=.034) (Table 4).
SF12 PCS scores were unchanged (Table 4).

23. Table 4: Modification of the Effect of LFSC Rupture by Co-Morbidities and Rupture Success
Direction of difference indicated by +/-. Value indicates the difference in score between presence and absence of covariate accounting for baseline differences.
Prior Lumbar Procedure
Obesity (BMI>30)
Rupture Success
Subsequent LESI
Subsequent Surgery
Effect Modifiers
∆ Score (95% CI) p
∆ Score (95% CI) p
Numeric Pain Score
+2.0 (0.4 , 3.6)
.014
+2.2 (0.5 , 3.9)
.010
+0.6 (-1.6 , 2.7)
.593
2.9 (1.3 , 4.5)
.001
-1.5 (-3.2 , 0.2)
.089
ODI
+17 (8 , 26)
.000
+2 (-8 , 11)
.722
-8 (-20 , 5)
.240
+11 (2 , 20)
-5 (-15 , 4)
.262
SF 12 PCS
-6 (-13 , 1)
.085
-4 (-10 , 3)
.258
-2 (-12 , 8)
.585
-5 (-12 , 2)
.148
+6 (0 , 13)
.050
SF 12 MCS
.244
-3 (-9 , 4)
.373
-3 (-11 , 5)
.481
-7 (-13 , -1)
.034
**General linear mixed model with interaction terms. p-values correspond to the significance of differences in score changes pre to combined post-procedure by covariates
**Scores obtained after a patient progressed to surgery were excluded.

24. Results
72% of patients self-reported regular pain medication use at the time of procedure, including 16% opiate and 54% non-opiate regimens.
39% were able to wean entirely off pain medication by 1 week post- procedure (McNemar p=0.001).
Excluding patients who progressed to back surgery, this response was durable through 1 year with 34% remaining weaned off pain medication (McNemar p=.039).

27. Conclusion
Our results confirm along multiple outcome measures that percutaneous rupture of symptomatic LFSCs rupture is a durable and effective treatment.
44 patients with lumbar facet synovial cysts showed significantly improved functional health and well-being, decreased low back pain disability, and decreased use of pain medication.

28. Conclusion
Obese patients and those with a history of previous lumbar spinal surgery or percutaneous spinal procedures scored lower on several post-procedure patient-reported outcome measures.
Unsuccessful cyst rupture did not predict need for subsequent surgery.

29. References
Abdullah AF, Chambers RW, Daut DP. Lumbar nerve root compression by synovial cysts of the ligamentum flavum. 1984;60:617–20.
Brish A, Payan HM. Lumbar intraspinal extradural ganglion cyst. Journal of neurology, neurosurgery, and psychiatry [Internet] Dec;35(6):771–5.
Kao CC, Uihlein A, Bickel WH, Soule EH. Lumbar intraspinal extradural ganglion cyst. J Neurosurg 1968;29:168–72.
Kurz LT, Garfin SR, Unger AS, et al. Intraspinal synovial cyst causing sciatica. J Bone Joint Surg Am 1985;67:865–71.
Alicioglu B, Sut N. Synovial cysts of the lumbar facet joints: a retrospective magnetic resonance imaging study investigating their relation with degenerative spondylolisthesis. Prague medical report [Internet] Jan;110(4):301–9.

30. References
Allen TL, Tatli Y, Lutz GE. Fluoroscopic percutaneous lumbar zygapophyseal joint cyst rupture: a clinical outcome study. The spine journal : official journal of the North American Spine Society [Internet] May;9(5):387–95.
Apostolaki E, Davies AM, Evans N and Cassar-Pullicino VN. MR imaging of lumbar facet joint synovial cysts. European Radiology Volume 10, Number 4 (2000),
Pytel P, Wollmann RL, Fessler RG et al. Degenerative Spine Disease Pathologic Findings in 985 Surgical Specimens. Am J Clin Pathol 2006;125:
Martha JF, Swaim B, Wang DA, et al. Outcome of percutaneous rupture of lumbar synovial cysts: a case series of 101 patients. The spine journal : official journal of the North American Spine Society [Internet] Dec;9(11):899–904.
Doyle AJ, Merrilees M. Synovial cysts of the lumbar facet joints in a symptomatic population: prevalence on magnetic resonance imaging. Spine [Internet] May 15;29(8):874–8.