An experimental study of intervertebral disc nucleus pulposus coagulation by alum

Xianyi LIU; Tianyue ZHU

ABSTRACT

BACKGROUND:

The main pathological change of intervertebral disc herniation is that nucleus pulposus protrudes from ruptured annulus fibrosus, thus we can hypothesize that it is possible to prevent disc herniation prior to its protrusion by coagulating it as a whole.

OBJECTIVE:

To observe the coagulation effects of intervertebral disc nucleus pulposus by alum solution.DESIGN, TIME AND

SETTING:

A randomized controlled animal experiment was performed between September 2002 and April 2003 at Department of Animal Experiment, Peking University First Hospital, Beijing China.MATERIALS Twenty-six healthy adult hybrid dogs, 9 for in vitro experiment and 17 for in vivo experiment, weighing 16-21kg, with no restrictions on male and female, were obtained from Department of Animal Experiment, Peking University First Hospital, Beijing, China.

METHODS:

Twenty canine in vitro intervertebral discs obtained from 5 dogs were randomly divided into 4 groups, with 5 discs in each group, and were put into 2.5%, 5%, 10% alum solutions and 0.9% physiological saline, respectively. Effects of disc coagulation were observed after immersing for 1 day and 10 days, respectively. Another 16 in vitro intervertebral discs obtained from 4 dogs, composed of L2/3, L3/4, L4/5, L5/6, were also injected with the above 4 experimental solutions, 0.15ml, respectively. Sixty-eight in vivo intervertebral discs were obtained from 17 dogs and divided into 4 groups blank control group, physiological saline group, 10% alum solution+one puncture point group, and 10% alum solution+two puncture points group, 17 discs in each group. Harvesting time 3 days, 2 weeks, 1 month and 3 months postoperation.MAIN OUTCOME

MEASURES:

Effects of alum solutions on the coagulation of the intervertebral discs and related histological changes were observed and an alum solution of suitable concentration was preliminarily selected. General observation, light microscopic observation and scanning electron microscopic observation were made of the nucleus pulposuses.

RESULTS:

In the in vitro and in vivo experiments, it was found that physiological saline did not produce the effect of coagulation on the nucleus pulposus, while immersion in the alum solution induced nucleus pulposus coagulation in the in vitro intervertebral discs. Also, as the concentration of the alum solution increased, the volume of the coagulated nucleus pulposus gradually decreased. After alum solution was injected into the in vitro intervertebral discs, no nucleus pulposus coagulation appeared. When the 10% alum solution was injected into the in vivo intervertebral discs, nucleus pulposus coagulation occurred, with the strongest coagulation effect reached at 1 month postoperation. This was manifested in the agglutination reaction centered around the puncture point. When there were 2 puncture points, 2 coagulated lumps might appear. There was an increase in the mesenchymal component of the coagulated nucleus pulposus. Histochemical and scanning electron microscopic examinations confirmed the proliferation of large numbers of collagen fibers in the mesenchyme.

CONCLUSION:

Alum can promote nucleus pulposus to coagulate around the injection point. This may be related to the increase of collagens and the fibrosis resulting from stimulation of the nucleus pulposus by alum solution.