title: Short-term experience with a new absorbable composite cage (β-tricalcium phosphate-polylactic acid) in patients after stand-alone anterior cervical discectomy and fusion.
abstract: METHODS
  Prospective clinical single center series with 50 patients to include, with planned follow-up intervals at 3 and 12 months postoperative.
  
  
  OBJECTIVE
  Absorbable cages were developed with the purpose to enhance fusion rates and to reduce the rate of cage subsidence. The gradual increase of load transfer during cage degradation facilitates new bone formation, which possibly leads to higher arthrodesis rates.
  
  
  BACKGROUND
  Absorbable cages consisting of a mixture of polylactic and polyglycolic acid (PLLA-PGLA) or poly (L-lactide-co-D, L-lactide) experimentally showed disappointing results with formation of cartilage and fibrous tissue components, which was much less pronounced using composite cages consisting of a polymer and calciumphosphate.
  
  
  METHODS
  Patients showing degenerative cervical mono- or bi-level pathology were prospectively included. Using anteroposterior and lateral radiographs, segmental height of the treated segments was determined quantitatively. Cage characteristics were described qualitatively. Clinical data such as the Neck Disability Index, pain severity on the visual analogue scale were collected at all time points separately for neck and arm.
  
  
  RESULTS
  A total of 33 patients were included, with a mean age of 51.9 ± 9 years. As cage dislocations occurred in 4 out of 33 patients (12.1%), the study was prematurely discontinued. All patients with cage dislocations were surgically revised. Clinical outcome of the remaining patients showed significant improvement of visual analogue scale neck pain from 6.0 ± 2.5 to 2.8 ± 2.3 (P < 0.005), visual analogue scale arm pain from 5.3 ± 2.7 to 1.6 ± 1.6 (P < 0.005), and Neck Disability Index from 21.2 ± 8.6 to 12.5 ± 9.6 (P < 0.005) after surgery.
  
  
  CONCLUSIONS
  Because of the high rate of cage dislocations, the use of the present composite cage cannot be recommended as a stand-alone device unless implant fixation will not be improved significantly. Evaluation of clinical and radiological long-term effects is essential to estimate the potential benefit of composite cages.
  
  
  METHODS
  2.
authors: Department of Neurosurgery, University Medicine Mannheim, Medical Faculty Mannheim of the University of Heidelberg, Germany.
authors: Christopher
authors: C
authors: Brenke
authors: Stephanie
authors: S
authors: Kindling
authors: Johann
authors: J
authors: Scharf
authors: Kirsten
authors: K
authors: Schmieder
authors: Martin
authors: M
authors: Barth
mesh_terms: D000328:Adult; D002130:Calcium Phosphates / Q000627:therapeutic use; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D004185:Disability Evaluation; D017586:Diskectomy / Q000295:instrumentation / Q000379:methods*; D005500:Follow-Up Studies; D006801:Humans; D019344:Lactic Acid / Q000627:therapeutic use; D008875:Middle Aged; D019547:Neck Pain; D009984:Orthopedic Fixation Devices; D010147:Pain Measurement; D011091:Polyesters; D011108:Polymers / Q000627:therapeutic use; D011446:Prospective Studies; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D002130:Calcium Phosphates; D011091:Polyesters; D011108:Polymers; C485817:beta-tricalcium phosphate; D019344:Lactic Acid; C033616:poly(lactide)