The emerging significance of amyloid deposits in the ligamentum flavum of spinal stenosis patients: A review.

Spinal stenosis is one of the most common neurosurgical diseases and a leading cause of pain and disability. Wild-type transthyretin amyloid (ATTRwt) has been found in the ligamentum flavum (LF) of a significant subset of spinal stenosis patients who undergo decompression surgery. Histologic and biochemical analyses of ligamentum flavum specimens from spinal stenosis patients, normally discarded as waste, have the potential to help elucidate the underlying pathophysiology of spinal stenosis and possibly allow for medical treatment of stenosis as well screen for other systemic diseases. This review article discusses the utility of analyzing LF specimens following spinal stenosis surgery for wild-type transthyretin amyloid (ATTRwt) deposits. Screening of cardiac ATTRwt amyloidosis (ATTRwt-CM) through LF specimens have led to the early diagnosis and treatment of cardiac amyloidosis in several patients, with more expected to benefit from this process. Emerging evidence in the literature also point to ATTRwt as a contributor to a previously unrecognized subtype of spinal stenosis in patients who may in the future benefit from medical therapy. In this article, we review the current literature with regards to the early detection of ATTRwt-CM via LF screening as well the possible contribution of ATTRwt deposits in the LF to spinal stenosis development.