Remodelling of the sacrum in high-grade spondylolisthesis: a report of two cases

Abstract

IntroductionWiltse et al. [41] proposed a classification of spondylolysis and spondylolisthesis, the different forms being defined as: dysplastic, isthmic, degenerative, traumatic and pathological spondylolisthesis. Most high-grade spondylolisthesis patients have an isthmic form, but often with dysplastic phenomena such as a bifid arch or subluxation of the facet joints.The treatment of high-grade spondylolisthesis (slip percentage of more than 50%, Meyerding grade 3, 4 or 5) is highly controversial. This condition is relatively rarely seen, and large series comparing non-operative and operative treatment or different operative treatments are not available. Although Weinstein mentions, in a review article [40], that 11 non-operated patients with a high-grade spondylolisthesis led an active life with only minor adjustments 18 years after the original diagnosis, most patients and orthopaedic surgeons favour an operative treatment [21]. In the same review article, 21 patients treated by fusion in situ had even fewer symptoms than the untreated group. The degree of slip did not influence the re-sults. However, several other authors mention dissatisfaction among patients after a fusion in situ for high-grade spondylolisthesis [6, 17]. Even neurologic complications are described after fusion in situ [23,32], but they are more frequent after reduction manoeuvres [1, 5, 6, 14,24,26]. The literature seems convincing on the fact that fusion in situ is a good and relatively safe option for patients with significant complaints due to a high-grade spondylolisthesis [13, 15, 16,29,33,34]. This in fact is rather surprising, since the original deformity is not dealt with. MRI observations in two patients lead us to believe that remodelling of the upper sacrum and the lumbo-sacral junction could play a role in achieving these good results. Case reports Case1A 12-year-old girl was first seen with fatigue in the lumbar region of 1 year's duration. She experienced pain in her legs, which disappeared after she stopped jazz ballet and ballroom dancing. Forward bending was severely restricted, to 20°, and straight leg raising was only possible to 45°bilaterally. The strength of the m. ex-Abstract Two young patients are described, who were operated on for high-grade spondylolisthesis. A good posterolateral fusion was achieved, without decompression and without reduction. The clinical course was favourable, the tight hamstring syndrome resolved. Disappearance of the posterior-superior part of the sacrum and of the posterior part of the L5-S1 disc was observed on comparing pre-and postoperative magnetic resonance (MR) images. This resulted in normalisation of the width of the spinal canal. Around the L5 nerve roots in the L5-S1 foramina some fat reappeared. These anatomical changes on MRI could play a role in the disappearance of clinical symptoms.