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

ASPN SCIENTIFIC PAPER SESSION D
Brachial Plexus Surgery in a German Center for Peripheral Nerve Surgery
Institution where the work was prepared: University of Tuebingen, Tuebingen, Germany
Nektarios Sinis, MD; Tatjana Lanaras; Hans-Eberhard Schaller, MD; University of Tuebingen
Brachial plexus lesions are still associated with complete or partial plegia of affected muscles even though the microsurgical concepts
and treatment options were improved during the past twenty years. This work should provide an overview of strategies and outcomes
of 42 patients operated in a center for peripheral nerve surgery in the southwest of Germany. The patients were followed after surgery
and examined for muscle strength of different muscle groups following the classification introduced by Loved et al. (M0 ñ no function
to M5 ñ full function) and sensitivity (differentiation of blunt and sharp touch in different dermatomes). They were asked with a short
questionnaire about their experiences and daily life after surgery. The longest follow-up was 96 months while the shortest was four.
Mean time past between trauma and operation was 7.1 months. 93% of the patients received a grafting procedure using the sural nerve.
Different procedures were applied referring to the underlying pathology: Intercostal nerve transfer, end-to-side coaptation of donor and
recipient nerves (one case of phrenic nerve to axillary nerve), direct grafting between roots, cords and trunks to different recipient
nerves. At the time of examination 27 patients had a follow-up time of at least 36 months. Only these patients presented a measurable
function in the affected extremity. In general the results for reconstruction of proximal muscle groups were more satisfactory than those
in distally located muscles (e. g. short muscles of the hand, exception the deltoid muscle). Elbow ñ flexion was restored in 56 % of cases
(i. e. muscle strength of at least M3). Triceps function was successfully reconstructed in 26 % of cases. Hand function was in contrast poor
except of one case with full regeneration after neurolyisis. Nevertheless, some developed an acceptable force of the forearm muscle
groups with the ability to flex the wrist in 37 % and for wrist extension in 17 %. Results were estimated as acceptable for biceps reconstruction
but poor for the other muscle groups. Some treatment strategies which are today under frequent discussion (contralateral C7transfer,
banked autografts, Oberlin procedure) were not applied. However, some of these techniques may provide a key to improve
the results, therefore frequent exchange in form of specialist meetings for different concepts and surgical techniques should be performed
by centers operating brachial plexus lesions in order to share their experiences with the others.
Effect Of Nerve Growth Factor (NGF) Releasing Polylactic-Co-Glycolic Acid (PLGA)
Microspheres On Peripheral Nerve Regeneration
Institution where the work was prepared: Mayo Clinic, Rochester, MN, USA
Ralph De Boer, MD1; Huan Wang, MD, PhD1; Andrew M. Knight, PhD1; Robert J. Spinner1; M.J.A. Malessy2; Michael
J. Yaszemski, MD, PhD1; Anthony J. Windebank, MD1; (1)Mayo Clinic, (2)Leiden University Medical Center
INTRODUCTION:
Autologous nerve grafting is the standard method for repair of a peripheral nerve when direct coaptation is not feasible. Optimization
of artificial nerve conduits by incorporation of trophic factors may enhance nerve regeneration and improve outcomes for patients.
Consistent delivery of trophic factors for a prolonged period of time is therefore required. We have characterized the long term release
of nerve growth factor, using a microsphere delivery system and evaluated the effect on functional regeneration in a rat sciatic nerve
injury model.
METHODS:
In vitro: 125I-NGF was incorporated into PLGA microspheres with lactic to glycolic acid ratios of 50:50 (1A - inherent viscosity 0.1 dL/g);
50:50 (4A - inherent viscosity 0.4 dL/g); 50:50 (7A - inherent viscosity 0.7 dL/g); 75:25 and 85:15. Microspheres were placed in a transwell
and continuously shaken at 37'C for 10 weeks. Release of radioactivity into the medium was measured weekly by ?-counting. Biological
activity of released NGF was established using the E15 rat dorsal root ganglion (DRG) assay In vivo: An animal study has been initiated
with PLGA nerve conduits loaded with NGF releasing microspheres bridging a 10 mm gap in the rat sciatic nerve. An autologous nerve
graft and a conduit filled with saline were used as the positive and negative control respectively. Electrophysiological (CMAP, SEP), sensory
(Hargreaves) and motor testing (motion analysis) were carried out at baseline and at two week intervals after surgery. Retrograde
tracing will be performed before sacrificing the rats at 17 weeks. Sciatic nerves, along with appropriate spinal cord segments and dorsal
root ganglia will be harvested and analyzed for cell counting and nerve morphometric measurements.
RESULTS:
In vitro: Microspheres could be designed to gradually release NGF at a rate of 0.2-2.5% of total per day. There was a small (