Early results of stand-alone anterior lumbar interbody fusion in iatrogenic spondylolisthesis patients

Abstract

Background Iatrogenic spondylolisthesis is a challenging condition for spinal surgeons. Posterior surgery in these cases is complicated by poor anatomical landmarks, scar tissue adhesion of muscle and dural structures and difficult access to the intervertebral disc. Anterior interbody fusion provides an alternative treatment method, allowing indirect foraminal decompression, reliable disc clearance and implantation of large surface area implants. Materials and methods A retrospective chart review of patients with iatrogenic spondylolisthesis including preand post-operative Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores was performed. Imaging criteria were pelvic incidence, overall lumbar lordosis and segmental lordosis. In addition, the fusion rate was investigated after 6 months. Results Six consecutive patients treated between 2008 and 2011 (4 female, 2 male, mean age 61 ± 7.1 years) were identified. The initially performed surgeries included decompression with or without discectomy; posterior instrumented and non-instrumented fusion. The olisthetic level was in all cases at the decompressed level. All patients were revised with stand-alone anterior interbody fusion devices at the olisthetic level filled with BMP 2. Average ODI dropped from 49 ± 11 % pre-operatively to 26.0 ± 4.0 at 24 months follow-up. VAS average dropped from 7 ± 1 to 2 ± 0. Mean total lordosis of 39.8 ± 2.8°i ncreased to 48.5 ± 4.9°at pelvic incidences of 48.8 ± 6.8°pre-operatively. Mean segmental lordosis at L4/5 improved from 10.5 ± 6.7°to 19.0 ± 4.9°at 24 months. Mean segmental lordosis in L5/S1 increased from 15.1 ± 7.4°to 23.2 ± 5.6°. Cage subsidence due to severe osteoporosis occurred in one case after 5 months, and hence there was no further follow-up. Fusion was confirmed in all other patients. Conclusion Anterior interbody fusion offers good stabilisation and restoration of lordosis in iatrogenic spondylolisthesis and avoids the well-known problems associated with reentering the spinal canal for revision fusions. In this group, ODI and VAS scores were improved.

Anterior stand-alone fusion revisited: a prospective clinical, X-ray and CT investigation

“…Eur Spine J described a significant increase of segmental lordosis following ASAF with Synfix-LR at the level L5/S1 from 15.1°to 23.2°, respectively [69]. As the majority of the global lumbar lordosis is located within the last two key segments L4-S1, the current data reveal that ASAF techniques performed at these levels bear the advantage of a significant lordosis reconstruction, which may ultimately reduce the loads on adjacent levels.…”

„Iatrogenes Wirbelgleiten – Inzidenz, Risikofaktoren, Management“

“…Vor diesem Hintergrund fehlt ein Goldstandard als Therapie der iatrogenen Olisthese. Zusätzlich bleibt offen, wie das Ausmaß einer postoperativen Instabilität, beziehungsweise Olisthese, mit dem klinischen Outcome nach operativer Therapie korreliert [6,17,8]. Die Studienlage zum Management der Olisthese umfasst hauptsächlich die degenerative, isthmische oder dysplastische Form des Wirbelgleitens [23, 25 -27].…”

“…Von der iatrogenen Olisthese betroffene Patienten können Rückenschmerzen und Ischialgien als Symptome zeigen [6,28]. Bei Versagen konservativer Therapiemaßnahmen (inkl.…”

“…Als operative Vorgehen der Wahl kommen in der Regel dorsale Revisions-und Stabilisierungsverfahren für dieses Patientenkollektiv in Frage, um die Stabilität im betroffenen Segment erneut zu gewährleisten [6,32]. Im Rahmen einer dorsalen Revision erschwert jedoch das vernarbte Gewebe die Orientierung und führt somit zu vermehrten Komplikationen (Verletzung der Dura und neuraler Strukturen, etc) [6,28]. Vor diesem Hintergrund gibt es mittlerweile für die iatrogene Olisthese Studien, in denen Fusionsoperationen über einen stand-alone anterioren Zugang vielversprechende Ergebnisse zeigten [6,28].…”

“…Im Gegensatz dazu betrifft die indirekte Form das unmittelbar benachbarte Segment nach einer Fusionsoperation [4]. Die in der Literatur angegebene Inzidenz der iatrogenen Olisthese (3.7 -20 %) sowie der postoperativen Instabilität (0 -63 %) weist allerdings eine hohe Spannweite durch die fehlende einheitliche Definition dieser Diagnose sowie durch die Heterogenität der Patientenkollektive aus [5,6]. Mit zunehmenden minimalinvasiven Dekompressionsoperationen gegenüber der klassischen Laminektomie scheint die Inzidenz der direkten Form abzunehmen.…”