Floor plan - 2013 Annual Meeting - American Association for Hand ...

Repairing Peripheral Nerve Injuries Using Skin-Derived Precursor Cells
Institution where the work was prepared: University of Calgary, Hotchkiss Brain Institute, Calgary, AB, Canada
Sarah K. Walsh, BSc; Raj Midha, MD, MSc; University of Calgary
Previous work has shown that clones of progenitor cells isolated from the dermis of the neonatal and adult murine skin have the ability
to differentiate in vitro into neural crest cell types, including peripheral neurons and glia. These cells, termed skin-derived precursors
(SKPs), also respond to the milieu of the regenerating nerve in vivo and are able to differentiate into GFAP/S-100‚ positive Schwann cells
when transplanted distal to a nerve injury. In our ongoing study, we are exploring the viability and differentiation of SKPs in various nerve
injury models to ascertain their role in promoting nerve regeneration. To this end, the sciatic nerves of CD-1 mice were transected and
chronically denervated. SKPs or SKP-SCs were injected into the subepineurium distal to the transection either immediately following
injury or after 8 weeks of denervation. Immunohistochemical analysis 2-8 weeks following transplantation revealed survival and differentiation
of both naïve and pre-differentiated SKPs, with 73% of the surviving cells injected after established chronic denervation
expressing Schwann cell markers. Eight weeks following SKP transplant, survival of pre-differentiated SKPs was significantly higher than
that of the naïve preparation. This study also examined the potential for SKPs to improve nerve regeneration across a gap bridged by
a freeze-thawed nerve graft. Donor sciatic nerves were collected from adult Lewis rats and decellularized by repeated cycles of freezing
in liquid nitrogen and thawing in warm water bath. These syngeneic grafts were then used to bridge a 12 mm nerve injury gap in
Lewis rat recipients and SKPs-SCs or cultured Schwann cells were injected into the grafted area. Immunohistology after 4 weeks showed
survival of both cell types and early regeneration in SKP seeded grafts (as deemed by NF-stained axon counts) was comparable to those
seeded with Schwann cells. We expect that morphometrical and electrophysiological measurements of cell-treated nerve segments
after 8 weeks survival will show a similar contribution to regeneration. We therefore conclude that SKPs represent an accessible, autologous
source of Schwann cells for transplantation therapies that have the potential to survive over long time periods and improve
regeneration outcomes.
DASH as a Measurement of Outcome in Adult Brachial Plexus Reconstruction
Institution where the work was prepared: Mayo Clinic, Rochester, MN, USA
Keith A. Bengtson; Alexander Shin; Robert Spinner; Allen Bishop; Michelle Kircher; Mayo Clinic
No clear consensus exists on how to measure outcomes after adult brachial plexus reconstruction. The BMRC muscle strength scale is
the most popular measuring tool used to date. Unfortunately, this method has many shortcomings including its imprecision, lack of
inter-rater reliability, as well as the wide range of strength that is covered by the grade of 4/5. The DASH, however, “is the most validated
measure of upper extremity function in upper extremity disorders. The instrument's ease of use in a heterogeneous sample is possibly
its greatest advantage.” (Dowrick 2005). No studies have been published that measure DASH scores both before and after brachial
plexus reconstruction. The purpose of this study is to illustrate the usefulness of the DASH as an outcome measure in adult brachial
plexus reconstruction. Between the dates of November 2004 and October 2006, 34 patients underwent reconstruction of brachial
plexus injuries and completed both pre-operative and post-operative DASH questionnaires. Time of follow-up questionnaire ranged
from 5 months to 26 months (average of 15.4 months) depending on type of surgery and expected time period for neurologic recovery.
Improvement in DASH scores ranged from -27.5 (greater disability) to +29.2 with an average improvement of 11.2. Five different
patient groups were included based on type of neurologic injury. Each group showed a significant change in DASH score before and
after surgical intervention. Such responsiveness to change would indicate that the DASH is a sensitive outcome tool for the study of
adult brachial plexus reconstruction.
REFERENCE:
Dowrick AS. Gabbe BJ. Williamson OD. Cameron PA. Outcome instruments for the assessment of the upper extremity following trauma:
a review. Injury. 36(4):468-76, 2005 Apr.
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