Scanning Electron Microscopy Study On Filum Terminale With Tethered Cord Syndrome

BackgroundClassically TCS has been defined as a spectrum of congenital anomalies resulting in an abnormally low position of the conus medullaris that may lead to neurological, musculoskeletal, urological, or gastrointestinal abnormalities. Some scholars attributed it to a thickened filum terminale, and the term "filum terminale syndrome" was coined; others found symptomatic inprovement following the sectioning of the filum terminale and coined the term "tethered spinal cord". Most commonly TCS is related to spinal dysraphism. The signs and symptoms correlate with the radiological definition in which the conus medullaris is anatomically lower than the L2 vertebra. More recently, there have been descriptions of TCS in which patients are described to have the conus medullaris in a normal position on imaging but presenting with signs and symptoms consistent with TCS. Most of the patients with normal conus position but TCS are reported to have associated findings such as cutaneous stigmata, vertebral abnormalities, intradural lipoma, and neurological abnormalities on examination. In this patient population, symptoms of pain and bowel or bladder incontinence appeared to be responsive to detethering.There have been a lot of researches on TCS at home and abroad, but its basic research lagged behind, especially the structure of pathological filum terminale with TCS. For lack of comprehensive and systematic researches, its ultrastructural system will be further improved.ObjectiveTo determine the ultrastructural change of pathological filum terminale with TCS and improve the understanding in pathology and provide steady proof for diagnosis and treatment of tethered cord syndrome (TCS), fila terminalia (FTs) ultrastructure of children with TCS will be researched.MethodsBetween January and July 2009, a total of 50 affected children were admitted for treatment at the Third Affiliated Hospital of Zhengzhou University. This population included 24 males and 26 females between 1 day and 14 years of ages with an averge age of 3.5 years. Fifty fila from these children were sectioned, and divided into two groups by their thickness:one was thicker FTs (thickness over 2mm); the other was normal FTs (thickness not over 2mm). Their transverse and longitudinal sections were respectively submitted for scanning electron microscopy analysis.ResultsUltrastructural analysis confirmed the presence of abundant collagen bundles and adipocytes, sparse or invisible elastic and reticular fiber inside FT, but the latter two libers were still visible in the relative normal areas of FT; some abnormalities, such as thickening, distortion, adhesion or fusion to piece, relatively dense and disorderly arrangement at a different degree, were quite common for collagen fiber, some areas looked blurry and some crystallization appeared occasionally on their surface. In the second group, those changes as mentioned above were still exhibited, but slightly relatively. All the changes mentioned in both groups may exist alone, or concomitantly, rarely simultaneously. Moreover, they can be often seen focally, or disffusely occasionally. Conclusions1) Pathological filum with TCS often is thicker than normal filum, but normal filum is not necessary really normal, with a abnormal ultrastructure;2) The degree of structure changes is not always consistent with clinical manifestation s;3) Pathological filum with TCS often show abnormal proliferation of non-elastic components, such as collagen fibers, fat cells.