Regeneration of intervertebral disc tissue by resorbable cell-free polyglycolic acid-based implants in a rabbit model of disc degeneration.
METHODS
: Different biologic strategies exist to treat degenerative disc disease. Tissue engineering approaches favor autologous chondrocyte transplantation. In our one-step-approach, a resorbable cell-free polyglycolic acid (PGA)-based implant is immersed in serum from whole blood and implanted into the disc defect directly after discectomy.


OBJECTIVE
: The aim of our study was to investigate the capacity of a cell-free implant composed of a PGA felt, hyaluronic acid, and serum to recruit disc cells and stimulate repair tissue formation in vivo after microdiscectomy in a rabbit model.


BACKGROUND
: Disc tissue has a limited ability to regenerate after the degeneration process was once initiated. Therefore, we developed a cell-free resorbable implant that is able to attract local cells into the defect and induce proper repair tissue formation.


METHODS
: The cell-free implant consisting of PGA and hyaluronic acid was immersed in allogenic serum and implanted into the disc defect after discectomy in New Zealand white rabbits. One week and 6 months after the operation, the disc height index and the T2-weighted signal intensity index were determined using plane radiographs and magnetic resonance imaging. Finally, discs were explanted and investigated histologically. Animals with discectomy only served as controls.


RESULTS
: In our animal studies, we could demonstrate that the T2-weighted signal intensity of the operated discs decreased in both groups 1 week after surgery. However, after 6 months, the T2-weighted signal intensity index increased by 45% in the implanted group whereas the index decreased further by 11% in the sham group. This corresponded to changes in the disc height index. Furthermore, the histologic examinations indicated cell migration into the defect and showed tissue regeneration.


CONCLUSIONS
: The implantation of a cell-free PGA-hyaluronic acid implant immersed in serum after discectomy induces regeneration, resulting in improvement of the disc water content and preservation of the disc height 6 months after surgery.
Abbushi
Alexander
A
Department of Neurosurgery, Charité, Campus Virchow-Klinikum, University Medicine of Berlin, Germany.
Endres
Michaela
M
Cabraja
Mario
M
Kroppenstedt
Stefan Nicolas
SN
Thomale
Ulrich Wilhelm
UW
Sittinger
Michael
M
Hegewald
Aldemar Andres
AA
Morawietz
Lars
L
Lemke
Arne-Jörn
AJ
Bansemer
Victor-Götz
VG
Kaps
Christian
C
Woiciechowsky
Christian
C
D020341:Absorbable Implants; D000818:Animals; D004195:Disease Models, Animal; D017586:Diskectomy; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D007403:Intervertebral Disc / Q000473:pathology / Q000502:physiology* / Q000601:surgery; D008297:Male; D011100:Polyglycolic Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D011817:Rabbits; D012038:Regeneration / Q000502:physiology*; D013122:Spinal Diseases / Q000473:pathology / Q000628:therapy*; D023822:Tissue Engineering
D011100:Polyglycolic Acid; D006820:Hyaluronic Acid