A multicenter, prospective, randomized study protocol to demonstrate the superiority of a bone-anchored prosthesis for anular closure used in conjunction with limited discectomy to limited discectomy alone for primary lumbar disc herniation


  • Peter Douglas Klassen Department of Neurosurgery, St. Bonifatius Hospital GmbH Department of Neurosurgery Wilhelmstraße 13 49808 Lingen
  • Robert Hes Department of Neurosurgery, AZ Klina, Department of Neurosurgery, Brasschaat, Belgium
  • Gerrit Joan Bouma Sint Lucas-Andreas Ziekenhuis and Academic Medical Center, Department of Neurosurgery, Amsterdam, The Netherlands
  • Sandro Eustacchio LKH-Univ. Klinikum Graz Department of Neurosurgery Graz, Austria
  • Martin Barth University Hospital, Department of Neurosurgery, Bochum, Germany
  • Adisa Kursumovic DONAUISAR Klinikum Deggendorf, Department of Neurosurgery and Interventional Neuroradiology, Deggendorf, Germany
  • Senol Jadik University Hospital, Department of Neurosurgery, Kiel, Germany
  • Volkmar Heidecke Klinikum Augsburg, Department of Neurosurgery, Augsburg, Germany
  • Richard Bostelmann University Hospital, Department of Neurosurgery, Düsseldorf, Germany
  • Claudius Thomé Innsbruck Medical University, Department of Neurosurgery, Innsbruck, Austria
  • Peter Vajkoczy Charité Universitätsmedizin, Department of Neurosurgery, Berlin, Germany
  • Hans Peter Köhler Asklepios Westklinikum Hamburg, Department of Neurosurgery, Hamburg, Germany
  • Javier Fandino Kantonsspital Aarau, Department of Neurosurgery, Aarau, Switzerland
  • Richard Assaker Centre Hospitalier Régional Universitaire de Lille, Department of Neurosurgery, Lille, France
  • Erik Van de Kelft AZ Nikolaas, Sint-Niklaas, Belgium
  • Susanne Fröhlich Orthopädische Klinik und Poliklinik der Universität Rostock, Rostock, Germany
  • Wimar van den Brink Neurochirurgisch Centrum Zwolle, Zwolle, The Netherlands
  • Jason Perrin Universitätsmedizin Mannheim, Department of Neurosurgery, Mannheim, Germany
  • Jasper Wolfs MCH Westeinde, Department of Neurosurgery, Den Hague, The Netherlands
  • Mark Arts MCH Antoniushove, Department of Neurosurgery, Leidschendam, The Netherlands
  • Frederic Martens OLV Ziekenhuis, Department of Neurosurgery, Aalst, Belgium




Disc herniation, Reherniation, Anular closure, Discectomy


Background: Same-level reherniation and progressive degeneration with disc height loss are main causes of poor outcome after discectomy and may necessitate reoperation.  A novel prosthesis for anular closure was developed to address these causes.

Methods: The design of a multicenter, prospective, randomized, post-market superiority trial comparing limited lumbar discectomy augmented with this device (intervention group) with limited lumbar discectomy alone (control group) is presented.

Results: Patients with single-level (L1-S1) posterior or posterolateral disc herniation and radiologic confirmation of neural compression for whom at least six weeks of conservative treatment has failed are eligible.  Patients must have posterior disc height ≥5 mm at index level and baseline Oswestry and VAS leg pain scores of ≥40/100.  Intraoperatively, subjects meeting anular defect size criteria post-discectomy (4-6 mm tall and 6-10 mm wide) will be randomized to study groups in a 1:1 ratio using centralized, web-based software. A Bayesian statistical approach will be used to enroll 400 to 800 subjects who will be followed for at least 24 months.  Two co-primary endpoints will be assessed at 24 months: 1) a composite of leg pain, clinical function, disc height maintenance, and absence of reherniation, reoperation, and device failure; and 2) absence of reherniation based upon independent radiologic analysis.  

Conclusions: This type of analysis is becoming increasingly important as governments and health insurers continue to be pressured to spend limited healthcare funding wisely.


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Original Research Articles