[Therapeutic efficiency in multisegmental fusions of the lumbar spine]

The aim of this study was to evaluate of the efficiency of an internal fixateur used since 1998 in multisegmental spondylodesis of the lumbar spine.

The prospective study included 105 patients with degenerative changes or instabilities of the lumbar spine, who underwent an anterior and posterior stabilisation of more than two segments. The minimum period of follow-up was more than 6 months. There were several objective scores used for the evaluation of the efficiency (Oswestry score/visual analogue scale [VAS]). In addition, the quality of the new internal implant was assessed concerning the rate of loosening and failure of the implant. This new internal fixateur, produced as a titanium alloy, consists of pedicle screws and longitudinal rods with 5 mm diameter and connection elements. Upon pulling the nut a square stabilised situation is created. Altogether the three-segmental stabilisations predominated (n=77), 23 patients received a four-segmental, four patients a five-segmental stabilisation and one received a stabilisation of six levels, mainly involving the segments L3/4 to L5/S1. Because of severe deformities in 14 cases the pedicle screws were applied by computer-assisted navigation (Navitrak).

In 12 patients (11.4%) radiological signs of loosening of the inserted pedicle screws in the vertebra were diagnosed. The radiological analysis resulted in pseudarthrosis of 4 (1.2%) of the 349 amalgamated segments. There were no cases of material failure. The average value of the pain score preoperatively (VAS) was 7.7 (5-10, SA 1.3) and postoperatively 4.6 (1-10, SA 1.8). With regard to the Oswestry disability index the preoperative average value amounted to 51.9% (30-91, SA 11.8) and postoperatively 35% (12-74, SA 11.8). In all 98 (93.3%) patients were satisfied, 7 (6.7%) patients reported a decline of the subjective outcome.

This system achieved a high degree of patient satisfaction and showed a low rate of pseudarthrosis. Furthermore, it can be inserted for short and long fusions, as well in deformities.