Effect of a modified Nd:YAG laser technique on neuroma formation: An experimental study in rat sciatic nerve.
OBJECTIVE
Traumatic transection of a peripheral nerve is inherently associated with the development of neuroma at the end of the proximal stump, often leading to therapy-resistant pain. This study was designed to evaluate whether the neodymium:yttrium aluminum garnet (Nd:YAG) laser could prevent neuroma formation after neurectomy.


METHODS
The sciatic nerves of 14 rats were diffuse coagulated by defocused Nd:YAG laser (12 W power), and subsequently transected with additional focused laser energy. The control group consisted of contralateral nerves transected by microscissors. The nerves were reexposed at different time intervals up to 9 weeks after surgery, and evaluation consisted of macroscopy, and light and transmission electron microscopy.


RESULTS
True neuroma formation could not be observed after laser transection, and only five nerves formed a neuromatous bulb, with minimal adhesions to surrounding tissue. Microscissor transection resulted in widespread amputation neuromas, consisting of regenerating axons and connective tissue, and nervous tissue regenerating into surrounding tissue. Laser-transected nerves showed degenerative changes of the axons and myelin, while proliferation of Schwann cells could not be observed. No outgrowth of axons could be observed outside the coagulated proximal stump. An epi/perineurial layer was present, covering the nerve stumps. Microscissor-transected nerves showed proliferation of fibroblasts and Schwann cells, forming minifascicles, and vigorous outgrowth of axons into the tissue and even into the distal nerve stump.


CONCLUSIONS
Within the limitations of this study it is concluded that the formation of amputation neuromas is suppressed by Nd:YAG laser application by thermal coagulation of the nerve and suppression of Schwann-cell proliferation.
Menovsky
T
T
Department of Neurosurgery, University Hospital Nijmegen St. Radboud, 6500 HB Nijmegen, The Netherlands.
Beek
J F
JF
Weerman
M V
MV
van Overbeeke
J J
JJ
D000818:Animals; D005260:Female; D053685:Laser Therapy / Q000009:adverse effects; D017169:Neoplasms, Post-Traumatic / Q000473:pathology / Q000517:prevention & control; D009463:Neuroma / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D010524:Peripheral Nervous System Neoplasms / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000293:injuries / Q000473:pathology / Q000601:surgery*