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Pérez et al. End-to-side neurorrhaphy for early reinnervation

this decrease was not significant. This was not observed The current study demonstrates the clinical importance
in the current study. It is possible that neurotomy of limiting muscular damage by using a “babysitter” to
of the donor nerve, by itself may in fact enhance preserve motor function after proximal nerve injuries in
reinnervation of the recipient nerve, perhaps due to the upper extremity before muscle atrophy is completely
a normal inflammatory response with recruitment of established. Several factors may alter the result. First,
neurotrophic factors. [19] both the injury mechanism and the experimental model
are crucial. Crush injury distal to the coaptation site
After repair of the neurotomy of the peroneal nerve has been found to increase the rate of myelin formation
by means of EEN, and connection to the tibial nerve in regenerating axons. [23] Further research is required
with an ESN using a neural graft with removal of an to determine the role of pre-injury, as deliberate donor
epineural window, an 18% extra-axonal density was nerve axotomy is critical for optimization of motor neural
obtained closer to the muscle in the group 0, partially regeneration as demonstrated in several studies. [16-18]
avoiding muscular atrophy and therefore improving the Recent research suggests that the number of axonal
motor and sensory functions. sprouts correlate with the degree of donor nerve
manipulation secondary to liberation of neurotrophic
A novel experimental model using the common factors, rather than the extent of the axotomy per se. [24]
peroneal nerve demonstrated that muscle mass The results of the current study suggest that the same
preservation was better achieved with sensory surgical principals can be applied to clinical practice
reinnervation rather than with motor reinnervation. No with patients. Clinical recovery is potentially faster
differences were found in this model when comparison and more efficient as the distance for nerve growth
was made between surgical techniques, whether they is shortened with the nerve graft placed near to the
were end-to-side or end-to-end. [20] muscle rather than waiting for normal axonal growth
from the injury´s site of origin. With the proposed
When the group treated with Viterbo´s principles (group treatment, irreversible muscular atrophy was avoided
2) was compared with our study group (group 3), a similar by supplying the target muscles with a constant neural
nerve graft diameter was found, but with a 36% increase impulse by means of this babysitter procedure. [25]
in axonal density in our proposed treatment group. Several applications for the ESN are currently being
studied. [26-30] The authors of the current study intend to
As a corrective procedure, EEN was combined with a study the usefulness of this procedure in the scenario
nervous graft coapting the peroneal and tibial nerves of acute trauma of the upper limb by creating nerve
through an epineural window by means of an ESN. bridges at the wrist crease in order to ameliorate ulnar
The number of new neural fibers exceeded those nerve injury, as it has been found that intrinsic muscle
present prior to section of the nerve, indicating a clearly function tends to be compromised despite the efforts of
beneficial sensory and motor effect. A significant a primary end-to-end repair.
decrease in axonal size, including the thickness of
myelin bands, was accompanied by a regenerative In conclusion, this study revealed a lower index of
process (sprouting); it is possible that when axons muscle fiber destruction, and can be a reliable method
regain their normal size and myelin bands reaches for reconstruction in high neural injuries. These results
their normal thickness, that the number of axons be may assist surgeons in the treatment of high neural
equal to the number of axons in the group 0. Although injuries in humans by performing nerve bridges at the
the current study protocol required that study subjects level of the wrist.
be sacrificed to obtain muscle and nerve samples, it Financial support and sponsorship
would be interesting to measure this parameter in a
later study. It is now accepted that collateral sprouting None.
is the main mechanism of nerve regeneration following
end-to-side neurorrhaphies. [17] Haninec et al. [21] Conflicts of interest
conducted a study to determine the utility of ESN There are no conflicts of interest.
from C5 to the ulnar nerve for motor and sensory
reinnervation. More collateral branches were found Patient consent
in the group in which a perineural window had been There were no patients involved.
performed. Although direct implantation of fibers into
the target muscle has been recently performed, it can Ethics approval
be avoided by performing an end-to-side procedure as The Ethics and Investigation Committees reviewed
proposed by Poppler et al. [22] and approved the investigation protocol (Protocol no.

22 Plastic and Aesthetic Research ¦ Volume 4 ¦ February 22, 2017