Child s Nerv Syst (1997) 13:298 – 335 © Springer-Verlag 1997 INVITED PAPER Congenital lumbosacral lipomas Alain Pierre-Kahn Michel Zerah Dominique Renier Giuseppe Cinalli Christian Sainte-Rose Arielle Lellouch-Tubiana Francis Brunelle Martine Le Merrer Yves Giudicelli Jacques Pichon Bernard Kleinknecht François Nataf Abstract Congenital lumbosacral lipomas can be responsible for pro- gressive defects. The general feeling is that tethering of roots, filum, or cord probably explains this evolu- tion, and that untethering of these structures could prevent late deteri- oration. Like the vast majority of neurosurgeons, we too have rou- tinely and systematically operated on lumbosacral lipomas, even in the ab- sence of neurological deficits. This policy stemmed from our belief that spontaneous neurological deteriora- tion was frequent, recovery from preoperative deficits rare, and sur- gery both efficient and benign in na- ture. After 22 years of experience, we felt that it was necessary to re- view our series of 291 lipomas (38 lipomas of the filum and 253 of the conus) operated on from 1972 to 1994. To reassess the value of pro- phylactic surgery, we attempted an accurate evaluation of (1) the risk of pathology, (2) the risks involved in surgery, (3) the postoperative out- come with respect to preoperative deficits, and (4) the postoperative outcome in asymptomatic patients at 1 year and at maximum follow-up. Special attention was paid to 93 pa- tients whose postoperative follow-up was more than 5 years (average 8.7, median 8, range 5–23 years). Of these 93 patients, 39 were asympto- matic preoperatively (7 with lipoma of the filum and 32 with lipoma of the conus). Lipomas of the filum and of the conus are entirely different lesions and were studied separately. In 6 cases prenatal diagnosis had been possible. The mean age at sur- gery was 6.4 years. Low back skin stigmata were present in 89.4% of cases. Preoperative neurological def- icits existed in 57% of the patients and were congenital in 22%. Clinical signs and symptoms recorded were pain in 13.3% of the patients and/or neurological deficits affecting sphincter (52%), motor (27.6%) and sensory (22.4%) functions. Deficits were progressive in 22.4% of cases, slowly progressive in 58.8% of these and rapidly progressive in the re- maining 41.2%. In 36 patients (13.2%) the lipomas were seen to grow either subcutaneously or intra- spinally. Among these patients, 21 were infants, 2 were obese ado- lescents, and 10 were pregnant women. The metabolism of the fat within the lipomas was studied in 11 patients and found to be similar to that at other sites. Lipomas were associated with various other malfor- mations, either intra- or extraspinal. These associated anomalies were rare in the case of lipomatous filum (5.2%) but frequent with lipomas of the conus, except for intracranial malformations (3.6%). Therapeutic objectives were spinal cord untether- ing and decompression, sparing of functional neural tissue and preven- tion of retethering. Procedures used to achieve these goals were subtotal removal of the lipoma, intraoperative monitoring, duroplasty, and some- Received: 25 November 1996 A. Pierre-Kahn () · M. Zerah · D. Renier G. Cinalli · C. Sainte-Rose · F. Nataf Department of Pediatric Neurosurgery, Groupe Hospitalier Necker-Enfants Malades, 149, Rue de Sèvres, F-75743 Paris Cedex 15, France Tel.: (33) 1-44 49 42 52 Fax: (33) 1-44 49 42 50 A. Lellouch-Tubiana Department of Anatomo-Pathology, Groupe Hospitalier Necker-Enfants Malades, 149, Rue de Sèvres, F-75743 Paris Cedex 15, France F. Brunelle Department of Pediatric Radiology, Groupe Hospitalier Necker-Enfants Malades, 149, Rue de Sèvres, F-75743 Paris Cedex 15, France M. Le Merrer Department of Genetics, Groupe Hospitalier Necker-Enfants Malades, 149, Rue de Sèvres, F-75743 Paris Cedex 15, France Y. Giudicelli Department of Biochemistry, Hôpital Necker-Enfants Malades, 149, Rue de Sèvres, F-75743 Paris Cedex 15, France J. Pichon Department of Neurological Rehabilitation and Physical Therapy, Hôpital de la Salpêtrière, 47, Boulevard de l’Hôpital, F-75013 Paris, France B. Kleinknecht Department of Neurophysiology, Groupe Hospitalier Necker-Enfants Malades, 149, Rue de Sèvres, F-75743 Paris Cedex 15, France