Outcome of retrospective and prospective multicenter cooperative clinical studies of spinal lipoma aiming for elucidating its natural history and for planning its treatment, and usefulness of neuroendoscope in its diagnosis and surgery assistance

The rate of manifestation of spinal lipoma (SL) is essentially unknown and propriety of its treatment is still controversial. Started in 2006 a prospective study by 7 facilities (COE-SB Top 7) to elucidate the natural history by such a mean as seeing the age distribution in SL manifestation, and to find applicable factors for conducting prophylactic surgery by such evaluation as improvable symptoms and surgical complication. Facilities also retrospectively summarized their outcomes of surgery and of conservative follow-up in the past 5 years. Further, evaluated was the usefulness of neuroendoscopic observation and assistance in diagnosis and operation, because diagnosis for predicting the neurological prognosis is often difficult by preoperative MRI alone and is changeable by surgical findings due to complex SL structures. This paper is a report describing tentative results of the prospective study above in the first 1 year, of the retrospective one and of the endoscopic utility. Subjects were 45 patients (21 cases, <1 year after birth; asymptomatic, 29 and symptomatic, 16) in the prospective study and 261 patients (asymptomatic, 159 and symptomatic, 102) in the retrospective. The endoscope used was an Oi-Samii Handy Pro type. Neurological symptom was assessed by Spina Befida Neurological Scale (1992). Patients were classified according to Embryo-pathogenetic and Surgico-anatomical Classification of Spina Bifida (2002). Results were: the prevalence was 15% at birth and increased afterwards; prognosis post surgery was poor in transitional SL; symptomatic improvement by operation was small; operative complication was scarce; and endoscope was conceivably useful for diagnosis and operative assistance. (R.T.)