Using the biomechanical model chapter 6 we

Using the biomechanical model (chapter 6) we demonstrated that RGTAs are effec-
tive in reducing the pull out force, i.e. neural adhesions, after nerve crush injury.
Regulation of HBGF activity by RGTAs effectuates a reduction of extraneural scar for-
mation, in particular regulation of TGF-beta, which promotes collagen deposition and
fibrosis.
The results of this study do not reveal positive or negative influence of RGTAs on
axonal regeneration as measured by magnetoneurography (chapter 3 & 4). Also, no
improved or accelerated recovery pattern of static TSF (chapter 2) was demonstrated
during the six weeks following injury. A lack of improved conduction capacity using
RGTAs may be explained by the type of injury. Following crush injury (axontmesis),
axonal regeneration is complete and relatively fast compared to total transection of a
nerve (neurontmesis). It is possible that the positive effect of RGTAs, i.e. reduction of
intraneural fibrosis, is not relevant in this type of injury in the rat model. When severi-
ty of injury is increased, for example in a nerve repair model, acceleration and improve-
ment of regeneration by the use of RGTAs may be demonstrated.
When comparing pull out force (POF) results of chapter 6 and chapter 7, there is no
significant difference between crush injury control groups six weeks after crush injury.
Mean POF (+ SEM) of control HA-gel study is 230.26 (+ 11.59 g) and mean POF (+
SEM) of control RGTA study is 206.96 g (+ SEM 13.90). The small difference may be
caused by the fact that these studies were performed by different investigators at differ-
ent time points. Yet, a striking difference is noted between the antiadhesion effect of HA-
gel and RGTAs. HA-gel effectuates a decrease of 29% in peak force, whereas RGTAs
accomplish a decrease of 67% in peak force after nerve crush injury. To demonstrate a
significant difference between both antiadhesion therapies both strategies should be
114

Research Perspectives
The general aim of this thesis was to quantify physiological and pathophysiological
processes, associated with the site of a possible nerve injury, in the rat sciatic nerve
model. Validated experimental methods providing quantifiable outcome data can pro-
vide solid evidence for potential beneficial strategies to promote recovery after periph-
eral nerve injury. It is not feasible to review all future possibilities in this field of
research. However, a few research perspectives can be summarized, which are directly
related to this thesis:
- In future experimental studies on promotion of recovery after nerve injury, the
type of assessment technique should carefully be considered. A quantifiable
measure is preferred, which is directly related to the hypothesis of the experi-
ment.
- Experimental research using Magnetoneurography requires an investment in
technical knowledge. The financial aspects of the recording set up are compara-
ble to other conventional neurophysiological methods. When deciding to per-
form neurophysiological measurements as an assessment method, ex vivo meas-
urements are preferable over conventional electrophysiology.