Histomorphometric and Radiographical Changes After Lumbar Implantation of the PEEK Nonfusion Interspinous Device in the BB.4S Rat Model

Barz, Thomas; Lange, Jörn; Melloh, Markus; Staub, Lukas P.; Merk, Harrry R.; Klöting, Ingrid; Follak, Niels (2013). Histomorphometric and Radiographical Changes After Lumbar Implantation of the PEEK Nonfusion Interspinous Device in the BB.4S Rat Model. Spine, 38(5), E263-E269. Lippincott Williams & Wilkins 10.1097/BRS.0b013e318280c710

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Study Design. An experimental animal study.
Objective. To investigate histomorphometric and radiographical
changes in the BB.4S rat model after PEEK (polyetheretherketone)
nonfusion interspinous device implantation.
Summary of Background Data. Clinical effectiveness of the
PEEK nonfusion spine implant Wallis (Abbott, Bordeaux, France;
now Zimmer, Warsaw, IN) is well documented. However, there is
a lack of evidence on the long-term effects of this implant on bone,
in particular its influence on structural changes of bone elements of
the lumbar spine.
Methods. Twenty-four male BB.4S rats aged 11 weeks underwent
surgery for implantation of a PEEK nonfusion interspinous device or
for a sham procedure in 3 groups of 8 animals each: 1) implantation
at level L4–L5; 2) implantation at level L5–L6; and 3) sham surgery.
Eleven weeks postoperatively osteolyses at the implant-bone
interface were measured via radiograph, bone mineral density of
vertebral bodies was analyzed using osteodensitometry, and bone
mineral content as well as resorption of the spinous processes were
examined by histomorphometry.
Results. Resorption of the spinous processes at the site of the
interspinous implant was found in all treated segments. There was
no significant difference in either bone density of vertebral bodies or histomorphometric structure of the spinous processes between
adjacent vertebral bodies, between treated and untreated segments
and between groups.
Conclusion. These findings indicate that resorption of spinous
processes because of a result of implant loosening, inhibit the
targeted load redistribution through the PEEK nonfusion interspinous
device in the lumbar spinal segment of the rat. This leads to reduced
long-term stability of the implant in the animal model. These results
suggest that PEEK nonfusion interspinous devices like the Wallis
implants may have time-limited effects and should only be used for
specified indications.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Evaluative Research into Orthopaedic Surgery

UniBE Contributor:

Staub, Lukas


600 Technology > 610 Medicine & health




Lippincott Williams & Wilkins




Ives Gerber

Date Deposited:

16 Jun 2014 11:08

Last Modified:

05 Dec 2022 14:32

Publisher DOI:


PubMed ID:






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