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Myelopathy Secondary to C5-C7 Cervical Synovial Cyst


The patient is a 53-year-old male presenting with the chief complaint of progressive weakness in his hands and legs. These symptoms became noticeable 3 months prior to his presentation and have progressively worsened.

At baseline, he ambulated independently despite knee and ankle contractures secondary to dermatomyositis, diagnosed at 18 months of age. In the few weeks preceding his admission, he started to require a walker and became wheelchair dependent since admission.

He also reported dropping objects and difficulty with fine motor movements. He denied any history of recent injury or trauma. He denied symptoms of urinary or bowel incontinence.


The physical examination was significant for weakness in the upper and lower extremities. The patient's exam revealed:

  • Profound weakness in the proximal muscles of the shoulder and hip girdle with 2/5 bilateral deltoids, hip flexors and knee extensors.
  • 2/5 strength in his left interossei and 3/5 strength on the right. His interossei were moderately atrophic.
  • Demonstrated a positive finger escape sign bilaterally.
  • Lower extremity exam demonstrated weakness throughout with 3/5 strength.
  • He reported paresthesia in the C6 to T1 distributions, mainly on the left.
  • Sensation was intact throughout the lower extremity.
  • Biceps and brachioradialis tendons were hyper-reflexive bilaterally.
  • Positive Hoffman’s sign bilaterally.
  • Patellar and Achilles tendon reflexives were 2+.
  • Down-going Babinski reflexes bilaterally.
  • Unable to ambulate secondary to unsteady gait and weakness.

Pre-treatment Imaging

The MRI of his cervical spine revealed a large extradural mass (8.4 mm in the anteroposterior dimension x 9.8 mm in the transverse dimension and 15 mm in the cranio-caudal dimension). It appeared to originate from the left C5-C6 facet and extended down to the C6-C7 level, displacing the thecal sac to the right (Fig. 1).

MRIs cervical spine; large extradural mass (synovial cyst)Figure 1. Cervical MRIs revealed a large extradural mass.

There was a mild spondylolisthesis of C6 on C7 with associated disc protrusion and posterior longitudinal ligament and ligamentum flavum hypertrophy to suggest instability at this level (Fig. 2A, 2B).

cervical sagittal MRIs, mild spondylolisthesis of C6 on C7Figure 2A. Cervical sagittal MRIs show mild spondylolisthesis of C6 on C7.

cervical axial MRIFigure 2B. Cervical axial MRIs.

The MRIs of the thoracic and lumbar spine were unremarkable for additional cysts or pathology.


Myelopathy secondary to a large multilevel cervical synovial cyst extending from C5 to C7.

Suggest Treatment

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Selected Treatment

Surgical decompression with fusion was recommended and the patient elected to proceed.

The patient underwent surgical decompression with instrumentation and fusion from a posterior approach. Bilateral laminectomies were made from C5 to C7.

An extradural mass was identified on the left and was carefully peeled from the dura and resected. The specimen was sent to pathology; and despite the classic appearance of a synovial cyst, diagnosis of synovial cyst was confirmed. (Fig. 3).

hemotoxylin and eosin staining of the tissue with fibrosis degenerative and vascular changes. 10X ERG staining vascular channelsFigure 3. Hemotoxylin and Eosin (H&E) staining of the tissue with fibrosis degenerative changes and vascular changes. 10X ERG staining highlights the vascular channels in the tissue.

Histopathology of cystic lesions derived from the synovial and ligamentous structures of the spine have been reported to demonstrate varied histological appearances.1

Lateral mass screws were inserted from C5-C7 using the Magerl technique (Fig. 4).

Lateral mass screws were inserted from C5-C7Figure 4. Lateral mass screws were inserted from C5-C7.

The patient tolerated the procedure well.


In the immediate post-operative period, the patient regained strength in his interossei muscles; however, he had minimal improvement in his lower extremities. Fortunately, at 3 months follow up, the patient showed substantial improvement in both upper and lower extremity strength.

The patient is currently able to ambulate with a walker and continues to make progress with spinal rehabilitation.

Authors' Case Discussion

Cervical synovial cysts are much less common than in the lumbar region.2,3,4 Machino et al, reported a total of 133 cervical cyst cases (including their own) as of 2012.5 Lyons et al, reported 35 cases of sub-axial cervical synovial cysts over a 17-year period.2 The most common level affected was at the C7-T1 level.

The etiology of synovial cysts is debated. One school of thought believes that cysts result from hypermobility of the facet joint.6 However, Lyons et al did not find a correlation of increased hypermobility on imaging at the C7-T1 level in their study looking at sub-axial cysts.7 Their alternative explanation postulates that the C7-T1 level represents a transitional zone that provides unique biomechanical forces and stresses on the facet joint. This would account for the higher incidence at the C7-T1 level versus the more mobile C6-C7 level.8

Spondylolisthesis and degenerative disc disease is commonly found in association with cervical cyst, which supports the mechanical stress theory.8,9 Independent of the etiology, subsequent degeneration of the facet joint can lead to the protrusion of the synovial membrane through a defect in the joint capsule, which results in cyst formation.6,8,9,10 As a result, sub-axial cysts occur more commonly in older patients or those with rheumatologic disease.8,11

Patients with sub-axial cervical cysts can present with myelopathy or radiculopathy, depending on the site of compression.12,13 Centrally located cysts will tend to cause myelopathic symptoms, while more lateral cysts typically present with radiculopathy from nerve root compression. Symptoms can progress rapidly. MRI is the preferred imaging for diagnosis and has low signal on T1 and high signal intensity on T2-weighted images.5,6 A peripherally enhancing mass will be seen if gadolinium contrast is used.

Gas within a cyst is pathognomonic for a synovial cyst. No intervention is required in asymptomatic cysts and spontaneous resolution has been reported. CT guided aspiration can provide a less invasive alternative if surgical decompression is not clearly indicated.14,15

Surgical decompression is effective for sub-axial cervical cysts that are symptomatic with neurologic deficit.8 Exposure is dependent on the size and location of the cyst. The posterior approach is commonly used for decompression given that the cysts are usually found along the posterolateral aspect of the spinal canal. Posterior cyst decompression can be achieved using a hemilaminectomy or full decompressive laminectomy.

Fusion would theoretically decrease the risk of recurrence by eliminating movement and degeneration of the facet joints. However, there are no documented cases where recurrence has occurred after surgical decompression without fusion.8 Patients may benefit from fusion in the presence of facet disease, multilevel degenerative disc disease, sagittal deformity, spondylolisthesis, or iatrogenic instability due to the decompression.8

If possible, resection of the cyst should include removal of the synovial lining. However, if the dura is adherent to the overlying cyst, compromising the dura to achieve complete synovial resection is not recommended given the low risk of recurrence, even with partial excision.5 Cyst removal using an anterior approach with corpectomy and fusion has also been described with successful results and can be used when indicated.4,16

In the previous literature, there is only one report documenting a cyst involving multiple levels and requiring multilevel decompression. Nijensohn et al, reported a cyst originating from the C5-C6 facet joint and extending proximally to C4-C5, requiring decompression at these levels.17 Posterior spinal fusion was used in this case. An additional report by Takano in 1992 reports a C3-C4 cyst from the ligamentum flavum, requiring a C3-C6 laminectomy without fusion.18 These are the only two previously documented reports of cervical cyst requiring multilevel decompression.

1. Chebib I, Chang CY, Schwab JH, Kerr DA, Deshpande V, Nielsen GP. Histopathology of synovial cysts of the spine. Histopathology. 2018 May;72(6):923-929.

2. Lyons MK, Birch BD, Krauss WE, Patel NP, Nottmeier EW, Boucher OK. Subaxial cervical synovial cysts: report of 35 histologically confirmed surgically treated cases and review of the literature. Spine. 2011;36(20):E1285-9.

3. Kao CC, Winkler SS, Turner JH. Synovial cyst of spinal facet: case report. J Neurosurg. 1974;41:372–6.

4. Jabre A, Shahbabian S, Keller JT. Synovial cyst of the cervical spine. Neurosurgery. 1987;20:316–18.

5. Machino M, Yukawa Y, Ito K, Kato F. Cervical degenerative intraspinal cyst: a case report and literature review involving 132 cases. BMJ Case Rep. 2012.

6. Shima Y, Rothman SL, Yasura K, Takahashi S. Degenerative intraspinal cyst of the cervical spine: case report and literature review. Spine. 2002 Jan 1;27(1):E18-22.

7. Christophis P, Asamoto S, Kuchelmeister K, Schachenmayr W. ‘‘Juxtafacet cysts’’, a misleading name for cystic formations of mobile spine (CYFMOS). Eur Spine J. 2007;16:1499–505.

8. Bydon M, Lin JA, de la Garza-Ramos R, Sciubba DM, Wolinsky JP, Witham TF, Gokaslan ZL, Bydon A. The role of spinal fusion in the treatment of cervical synovial cysts: a series of 17 cases and meta-analysis. J Neurosurg Spine. 2014;21(6):919-28.

9. McGuigan C, Stevens J, Gabriel CM. A synovial cyst in the cervical spine causing acute spinal cord compression. Neurology. 65:1293, 2005.

10. Cudlip S, Johnston F, Marsh H. Subaxial cervical synovial cyst presenting with myelopathy. Report of three cases. J Neurosurg. 1999;90(1)(Suppl):141–4.

11. Morio Y, Yoshioka T, Nagashima H, Hagino H, Teshima R. Intraspinal synovial cyst communicating with the C1-C2 facet joints and subarachnoid space associated with rheumatoid atlantoaxial instability. Spine. 2003;28:E492–495.

12. Bisson EF, Sauri-Barraza JC, Niazi T, Schmidt MH. Synovial cysts of the cervicothoracic junction causing myelopathy: report of 3 cases and review of the literature. Neurosurg Focus. 2014;35(1):E3.

13. Kayser F, Divano L, Vermer JF. Ganglion cyst of the cervical spine causing radiculopathy. J Radiologie. 1998;79(7):687–9.

14. Abrahams JJ, Wood GW, Eames FA, Hicks RW. CT-guided needle aspiration biopsy of an intraspinal synovial cyst (ganglion): case report and review of the literature. AJNR. 1988;9:398–400.

15. Kostanian VJ, Mathews MS. CT guided aspiration of a cervical synovial cyst. Case report and technical note. Interv Neuroradiol 2007;13:295–8.

16. Moon HJ, Kim JH, Kim JH, Kwon TH, Chung HS, Park YK. Cervical juxtafacet cyst with myelopathy due to postoperative instability. Case report. Neurol Med Chir (Tokyo). 2010;50(12):1129-31.

17. Nijensohn E, Russell EJ, Milan M. Brown T. Calcified synovial cyst of the cervical spine: CT and MR evaluation. J Comput Assist Tomogr. 1990;14.3:473–476.

18. Takano Y., Homma T., Okumura H., Takahashi H. E. Ganglion cyst occurring in the ligamentum flavum of the cervical spine: a case report. Spine. 1992;17(12):1531–1533. doi: 10.1097/00007632-199212000-00020.

Case Peer Discussion

The case presented illustrates progressive neurologic compromise as a result of posterior compression of the spinal cord secondary to a left-sided synovial cyst. While this patient has multiple preexisting conditions that affect his mobility, the acute nature of his presenting neurologic condition warrants a more immediate approach. Despite findings of multilevel degenerative cervical discs and facet spondylosis, based on the MRI findings, the patient’s symptoms do not include significant neck pain. The discovery of spondylolisthesis would not be unexpected. Decompression of the spinal cord is our goal. Spinal decompression is accomplished via traditional open laminotomy or less invasive tubular techniques. The tubular approach can negate the need for posterior fusion with instrumentation and would be this reviewer's preferred method.

Authors' Response to Case Peer Discussion

Dr. Knight, thank you for your comments:

Facet joint cysts occur due to a combination of degenerative and destabilizing changes in the spine.1 The most reliable data for facet joint cysts exists in the lumbar region. In a series of 166 patients treated, 17 patients had a recurrence at the same level after an average final follow-up of 36 months. All the patients who had recurrence had decompression alone.2 In a series of 314 consecutive patients, a higher number of re-operations in the non-fusion group (8.8%) occurred as compared with the fusion group (2.2%).3 Due to the cyst size, location, and spondylolisthesis at C6-C7 we felt that laminectomy and fusion was the appropriate choice.

1. Xu R, McGirt MJ, Parker SL, et al. Factors associated with recurrent back pain and cyst recurrence after surgical resection of one hundred ninety-five spinal synovial cysts: Analysis of one hundred sixty-seven consecutive cases. Spine 2010;35(10):1044-1053.

2. Campbell R, Phan K, Mobbs R. Classification of Lumbar Facet Joint Cysts Using the NeuroSpine Surgery Research Group (NSURG) Grading Score and Correlation with Recurrence and Clinical Outcomes. World Neurosurg. 2018;Vol. 119:e502-e512.

3. van Dijke M, Janssen SJ, Cha TD, et al. Comparison of Decompression With and Without Fusion for Patients With Synovial Facet Cysts. Clin Spine Surg. 2017;(30)10: E1399-E1404.

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