Nerve Repair Using Hydrophilic Polymers to Promote Immediate Fusion of Severed Axons and Swift Return of Function

Our own preclinical animal studies have been designed to take advantage of PEG. We have used
the fusogenic properties of PEG and this has allowed us to demonstrate a rapid and decisive
electrophysiological recovery of either crushed or completely severed sciatic nerves in a
commonly accepted mammalian model for peripheral nerve injury (Bittner et al JSR 2012).

Recently, we modified previously published mammalian techniques. Our goal was to eliminate
laboratory solutions that have not been approved for use in humans and replace them with
readily available reagents commonly used in clinical applications. PEG is commercially
available in many molecular formulations and our earlier experiments with PEG having a
molecular weight of 2 kD. Unfortunately, this molecular weight is not approved by the Food
and Drug Administration (FDA) for human usage. In our more recent preclinical studies, we
have demonstrated that PEG 3.35 kD, the main ingredient in the commonly used cathartic known
as MiraLAX© (MERCK; Whitehouse Station, NJ), actually generates superior fusion over PEG 2KD
in a cut nerve model. Thus the clinical trial that forms the basis of this proposal was
developed with the FDA approved 3.35 kD PEG and these other two FDA approved solutions.

Additional studies in our complex nerve injury model have also demonstrated that the repair
does not have to be performed immediately after nerve injury. Epineural repair with PEG 3.35
kD treatment can be performed up to 24hrs after injury and postoperative CAPs are obtained in
all PEG 3.35 kD treated animals (n=3, data not shown). The remarkable finding is that in the
24-hour injury model, PEG significantly improves behavioral outcome measured at 72 hours
postoperatively.

Based on the published reports and our own in vivo studies, we demonstrate that PEG based
repair can restore CAPs immediately and improve functional recovery significantly post
injury. These preclinical findings suggest that we can offer a novel therapy to test in
humans who have experienced complete transection of a peripheral nerve. Patient risk is
minimized as we have optimized the PEG facilitated fusion technique to utilize commonly used
FDA approved drugs, solutions and electrolytes to augment standard neurorrhaphy techniques.
The experimental protocol entails 100% transection injury to a peripheral nerve followed by a
standard neurorrhaphy. The repair is then irrigated gently with PEG for two minutes and
sterile water in standard fashion is used to wash away the PEG.

The most likely scenarios, that explain rapid compound action potential (CAP) restoration,
are the rapid restoration of cytoplasmic flow within the nerves, the rapid ability of
membranes to depolarize and possibly the prevention of Wallerian degeneration.

Inclusion Criteria:

- Diagnosis of a Sunderland Class 5 traumatic neuropathy (transection injury) of a
digital nerve in the upper extremity

- candidates for immediate operative repair (Arm 1);

- injury proceeding repair no longer than 72 hours; and

- repair within 48 hours of injury that require nerve grafting;

- N0 significant medical comorbidities precluding immediate repair;

- willing to comply with all aspects of the treatment and evaluation schedule over a 12
months period.

We plan to include subjects who have peripheral nerve injuries that are complicated by
significant vascular or orthopedic damage.

Exclusion Criteria:

- Patients will be excluded from enrollment if their injuries exhibit gross
contamination, in circumstances where soft tissue coverage is inadequate, or when
staged repair is planned.

- We will also exclude patients that are diabetic, have been diagnosed with a
neuromuscular disease, or are undergoing chemotherapy, radiation therapy, or other
treatments known to affect the growth of the neural and vascular system.

- We will exclude all patients currently enrolled in another investigational study or
those who are unlikely to complete the normal regime of occupational therapy.
Individuals will be excluded from participation if their time of injury falls outside
study parameters.