Ultra-structural changes of the lumbar spinal motor neurons after sciatic nerve injury induced by high-speed steel ball

Zhiyong YIN; Ping ZHOU; Hong HUANG

ABSTRACT

BACKGROUND:

What kind of traumatic changes could be observed in remote lumbar spinal cord after high-speed steel ball induced sciatic nerve injury?

OBJECTIVE:

To study the ultra structural changes of lumbar spinal cord motor neurons after the sciatic nerve injury due to high-speed steel ball.

DESIGN:

Retrospective randomized controlled study with experimental animals as subjects.

SETTING:

The field operation research institute of a military medical university college.MATERIALS This study was carried out at the Ballistic Laboratory of Research Institute for Surgery from May 2001 to December 2002. Sixty-five SPF flap-eared rabbits of either gender weighing from 2.5 to 3.0 kg were provided by the Experimental Animal Center of Daping Hospital Affiliated to the Third Military Medical Univeristy of Chinese PLA. All the rabbits were divided randomly into normal control group( n = 5), firearms injury group (n = 30) and cutting injury group( n = 30) . The two latter groups were subdivided into one-day, three-day, one-week, two-week, 4-week and twelve-week groups with 5 rabbits in each group.

METHODS:

The rabbits in the firearms injury group were injured at the midpoint of lateral posterior body surface projection of the right sciatic nerve with 0. 38 g steel ball containing 0.65 g detonators. The right sciatic nerve was cut at the same injury level in the cutting injury group.MAIN OUTCOME

MEASURES:

The following pathologic changes of the lumbar spinal cord were observed with optical and electronic microscope at posttraumatic day 1, day 3 and week 1, week 2, week 4 and week 12 respectively.

RESULTS:

Micro-hemorrhage, neuron swelling and vacuoles were observed in the firearms injury group and the number of motor neurons decreased significantly, but these changes were unobservable in the cutting injury group.

CONCLUSION:

Compared with the cutting group, the injury to the spinal cord was severer in the firearms group and the survival neurons were less.