title: [Keel-implants: Activ-L].
abstract: Due to its modular design, the Activ-L total disc replacement (B. Braun/Aesculap, Tuttlingen, Germany) allows for a flexible anchoring concept either with spikes or one or two keels. It has a semiconstraint design which allows for some movement of a UHMWPE inlay. The minimal invasive surgical technique is highly standardized. Early clinical results are comparable to established disc-replacement devices.
  
  
  OBJECTIVE
  Aim of the surgery is lasting pain relief and complete restauration of segmental mobility without affection of adjacent motion segments.
  
  
  METHODS
  Mono- or multisegmental lumbar disc degeneration leading to low-back pain, refractory to conservative treatment.
  
  
  METHODS
  Infections of vertebra or disc-space, fractures, prior fusion surgery of the affected motion segments, malignancy, osteoporosis, metabolic bone disease, severe conditions affecting general health, conditions prohibitive for anterior abdominal surgery, unclear or non-discogenic low-back-pain.
  
  
  METHODS
  Minimal-invasive anterior approach to the lumbar spine, removal of nucleus and cartilagenous endplates, sizing with trial implant, decision about spike or keel anchoring concept, implantation of prosthesis, x ray-control, wound closure.
  
  
  METHODS
  Bed-rest for 6 hours, stabilizing physiotherapy 3 weeks postoperative.
  
  
  RESULTS
  Level-3 evidence shows early clinical results comparable with published data from previous implants, particle wear of inlay is significantly lower, possibly due to different testing protocols.
authors.affiliation: Abteilung für Wirbelsäulenchirurgie, Hessingpark-Clinic, Augsburg, Germany. karsten.wiechert@hessingpark-clinic.de
authors.forename: Karsten
authors.initials: K
authors.lastname: Wiechert
mesh_terms: D001178:Arthroplasty / Q000295:instrumentation*; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D019736:Prostheses and Implants; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000379:methods*; D013122:Spinal Diseases / Q000601:surgery*; D016896:Treatment Outcome; D021801:Zygapophyseal Joint / Q000601:surgery*