. 2020 Aug;14(4):544-551.
doi: 10.14444/7072.
Epub 2020 Jul 31.
Affiliations
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et al.
Int J Spine Surg.
.
Abstract
Background:
Ligamentum flavum cysts have been rarely described in the literature and are one of the rare causes of neural compression and canal stenosis. Very few cases of their association with neurologic deficits are reported to date, and association with acute onset weakness is even rarer.
Clinical presentation:
We report our experience with 3 cases of ligamentum flavum cyst that presented with acute onset weakness and also present a comprehensive literature review on lumbar ligamentum flavum cysts reported to date. All 3 patients had symptoms of severe neurogenic claudication and presented to us with acute onset of motor weakness in lower limbs. Ligamentum flavum cyst was located in the midline in 2 cases and laterally in 1 case. We performed excision of the cyst and decompression with fusion in 2 cases and decompression alone in 1 case. All 3 cases had significant improvement in their neurologic status postoperatively. Histopathological examination confirmed ligamentum flavum cyst in all 3 cases. We performed a PUBMED and EMBASE database search using the MeSH (Medical Subject Headings) terms “ligamentum flavum” and “cysts” for articles published to April 2019. We could identify 7 studies describing 20 cases of lumbar ligamentum flavum cysts with motor weakness in the literature. Only 1 case had been described with an acute onset of weakness.
Conclusions:
Ligamentum flavum cysts should remain in the differential diagnosis of a patient who has symptoms of lumbar canal stenosis and presents with acute onset of neurological deficits. Such patients have a good improvement with surgery.
Keywords:
acute onset neurologic deficit; cyst excision and confirmed on histopathology; ligamentum flavum cyst; literature review and case series; lumbar spine.
This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery. Copyright © 2020 ISASS.
Conflict of interest statement
Figures
Case 1. (a, b) Sagittal T1- and T2-weighted magnetic resonance images of the patient showing a lesion hypointense on T1 and hyperintense on T2 within the posterior spinal canal at the L4–L5 level compressing the thecal sac (marked with blue arrow). (c, d) Axial T1- and T2-weighted MRI image at the L4–L5 level of the patient showing a lesion with hypointense signal (similar to cerebrospinal fluid signal) on T1 imaging and hyperintense signal on T2 imaging in the midline and slightly to the left (marked with blue arrow). (e, f) Anteroposterior and lateral x-rays of the lumbosacral spine of the patient showing degenerative changes at the L4–L5 and L5–S1 levels. Grade 1 spondylolisthesis at L5–S1 can be appreciated on the lateral view.
Case 1. (a, b) Postoperative anteroposterior and lateral x-rays of the patient showing posterior instrumentation from L4 to S1 and transforaminal lumbar interbody fusion at the L5–S1 level. (c) Image showing the excised ligamentum flavum cyst measuring about 1 cm in length. (d) Histopathological slide of the cyst shows a cystic lesion lined by a fibro-connective tissue with mild chronic inflammatory infiltrate and fibroblast proliferation. Few proliferating blood vessels are seen. There is no lining epithelium, consistent with a ligamentum flavum cyst.
Case 2. (a, b) Sagittal T1- and T2-weighted magnetic resonance images of the patient showing a lesion hyperintense on T2 and hypointense on T1 at the L4–L5 level within the posterior spinal canal compressing the thecal sac (marked with blue arrow). (c, d) Axial T1- and T2-weighted magnetic resonance images at the L4–L5 level of the patient showing a lesion with hypointense signal (similar to cerebrospinal fluid signal) on T1 and hyperintense on T2 in the midline (marked with blue arrow) compressing the thecal sac.
Case 2. (a, b) Postoperative anteroposterior and lateral x-rays of the patient showing posterior instrumentation from L4 to S1 with accurately placed screws. (c) Specimen showing the excised laminae (marked with white arrow) along with ligamentum flavum (marked with yellow arrow) en masse. The ligamentum flavum cyst (marked with blue arrow) can be clearly seen on the inner surface of the ligamentum flavum. (d) Histopathological slide of the cyst showing fibro-elastic tissue with chondroid metaplasia and areas of calcification. There is no lining epithelium, consistent with a ligamentum flavum cyst.