각종화합물의 주입이 가견요추간판(家犬腰椎間板)에 미치는 영향에 관한 실험적연구

Abstract

[한글]

[영문]

For centuries, the problem of low-back pain and sciatica has often been an enigma

to the medical profession. although much excellent work has been done on the

subject of backache, there is much left to be answered. An imposing list of

possible causes for this syndrome has been compiled which implicates various

structures and tissues in the pelvic and abdominal regions, however, convincing

pathological and anatomical evidence to incriminate these various structures is

frequently not to be found in patients who complain of low-back and sciatic pain.

Since the demonstration of Mixter and Barr, rupture of an intervertebral disc or

posterior protrusion of an intervertebral disc has been recognized as a clinical as

well as pathological entity and there has been a growing tendency among clinicians

to attribute low-back pain to derangements of the lumbar intervertebral discs in

the absence of other demonstrable causes. Furthermore, there are many who believe

that the lesions of an intervertebral disc are the only cause of idiopathic

low-back pain with or without sciatica. However, in many instances, we are not only

at a loss for an explanation of mechanism by which pain is produced but also

difficult to demonstrate the exact pathogenesis how the derangements of an

intervertebral disc is brought about.

This particular problem received a great deal of attention by many workers who

put forth many theories and arguments concerning degeneration of an intervertebral

disc and its relation to backache. Among the evidences, a trauma or physical

factors impinging upon an intervertebral disc has been considered to be playing a

major role in producing such lesions.

Quite frequently a practice of modern medicine requires a lumbar puncture for

diagnostic, anesthetic or therapeutic purposes. Particularly the use of lumbar

puncture in the investigation of lesions of the central nervous system has become

so standarized that it is almost as much of a routine procedure as the systematic

study of the reflexes.

The possibilities of serious damage to an intervertebral disc by needle puncture

are evident from the reports of many observers. Furthermore, over-enthusiasm is

leading some surgeons to deliberate insertion of a needle through the disc for the

purpose of injecting radio-opaque material for diagnostic purpose. Much concern has

been expressed by some who warned the possible deleterious effects of such

procedures.

While this particular problem has been a concern to many clinicians and

8investigators in this field, we know of no work previously done dealing with this

specific problem. Therefore a following experiment is planned to investigate the

effects of injecting various chemical solutions directly into the intervertebral

discs and clarify some aspects of disc degeneration.

Materials and Methods:

Fourty healthy mongrel dogs of various breeds were utilized. Each animals was

subjected to simple X-ray visualization of spinal column and myelography to check

the abnormalities of spine before experimental procedures. The chemical solutions

selected were Pantopaque, Diodrast, Procaine hydrochloride and Normal Saline which

are commonly used in the practice for the purposes of myelography, discography,

subarachnoidal block or other diagnostic procedures.

The animals were divided into five groups, namely pantopaque group, diodrast

group, procaine group, saline group and multiple puncture group.

Under pentothal sodim anesthesia, pararectal incision was made to visualize the

lumbar intervertebral discs trans-peritoneally. Under direct observation of an

individual disc, 0.2 to 0.4 c.c. of designated solutions were injected through 21

gauge needle. Each animal received injections into 4 intervertebral discs. The

multiple punctures were made with 21 gauge needle for 10 to 15 times into the disc.

Following injection of pantopaque and diodrast each animal was X-rayed to confirm

the correct insertion of dyes into the disc.

After operative procedures, the animals were sacrificed in the intervals of 24

hours, 72 hours, 1 week, 2 weeks, 3 weeks and 4 weeks respectively. Individual disc

was separated from the vertebral column, the gross features carefully recorded and

photographed and fixed into 10% neutral formalin. Paraffin section were stained

with Hematoxylin and Eosin, Periodic Acid Schiff reaction, Toluidine blue and

Mallory's Azan Stains.

Results:

As compared with the control discs, the experimental discs all showed one or more

of pathological changes as shown in the tables and figures. The most devastating

damage had occurred in the annulus fibrosus and nucleus pulposus.

Macroscopically, the cartilage plates showed little or no alterations except for

some fragmentation and hemorrhage in the multiple puncture group. The changes in

the annulus fibrosus were more marked in the multiple puncture group and less

marked in the diodrast and pantopaque groups, these changes were characterized by

irregularity of running fibers of annulus resulting in disorganized pattern at the

boundaries with the nucleus pulposus. The surfaces often showed irregular ups and

downs. The nucleus pulposus of the multiple puncture group showed hemorrhage,

fragmentation and irregular bulging of structures. In some discs, the entire

nuclear material was lost at the time of examination. The nucleus pulposus of

saline injected discs showed irregular shrinkage and fragmentation. The procaine

injected discs showed somewhat transparant appearance of discs and discoloration of

surface appearance. The diodrast injected discs showed cloudy discoloration.

Brownish surface with hemorrhagic spots were often present but these changes

gradually disappeared as the time lapsed. The pantopaque group showed little

changes in the gross appearance of nucleus but considerably the nuclear materials

were lost.

Microscopically, the majority of the experimental discs showed inflammatory

reactions centered around the sites of needle punctures. The inflammatory reaction

occurred quite early and became fibrotic very soon but the fibroblastic reaction

was mainly localized on the surface and the inner portions of annulus remained

broken for a long time. Oftentimes, small blood vessels invaded into the bundles of

annulus. Fragmentation and radial splitting of the annulus together with mucinous

swelling and degeneration was very common, Vacuolization of annulus was also

frequently observed.

Oftentimes, particularly in the multiple puncture group, the nuclear materials

herniated through the openings created by broken annulys. the herniated materials

formed swollen pockets surrounded by fibrosis and healed inflammatory reaction.

The nucleus pulposus of saline injected group showed extreme shrinkage of

cytoplasm of notochordal cells with loss of much of them. The procaine injected

group showed more of ground substance which were stained heavily with P.A.S. and

Toluidine blue stains. The cells in this group showed shrinkage of cytoplasm but

also contained scattered swollen physalipherous cells. The diodrast group showed

more changes in the annulus and cartilage plates and created herniation of nuclear

material. The nucleus pulposus showed loss of cells, and irregular fragmentation of

reticular fibers.

The pantopaque group showed similar changes with that ween in diodrast group but

the cellular degeneration was quite more apparent. Hemorrhage, inflammation and

fragmentation of nuclear material were the common findings in the multiple puncture

group.

The cartilage plates remained relatively intact in all the experimental discs

however in some, cystic degeneration and calcification was noted.

Comment and Conclusion:

From the data obtained above, it is quite apparent that injection of various

chemical solutions into an intervertebral disc causes a significant pathological

alterations. The fact that simple multiple puncture and injection of normal saline

has also caused serious damage to an intervertebral disc should be seriously taken

as a clear warning toward the abuse of inadequate lumbar punctures.

In many aspects, the morphological changes seen in the present investigation were

quite similar to the changes seen in so-called degenerated discs. Although there

were some minor differences between the chemicals utilized, the changes appeared to

be of similar nature and severity. The multiple puncture of an intervertebral disc

created, however, the most devastating damage among the groups.

Intervertebral disc is not just a static anatomical structure but is a dynamic

structure constantly functioning. From the earliest investigations, it has been

said that the efficient functioning of the disc depends largely on the elasticity

of the nucleus pulposus and that this in turn is closely related to its

water-binding capacity. It is also known that in early life a water content of

80∼88% is usually quoted and in later life figures of 70% may occur.

This change is usually accompanied by an alteration of morphology of the nucleus.

The changes in the water-binding capacity have been thought to be related to the

biochemical alterations occurring in the degenerated disc. The delicate mechanism

of water balance can be upset by eve minute tears in the annulus or the plates if

one assumes that the disc is an osmotic system.

There are others who claim that the imbibition pressure and not the osmotic

pressure is responsible for the hydration of nucleus pulposus. In any event,

however, the derangement of this water-binding mechanism caused by introduction of

chemical solutions might have caused such a degenerative changes observed in this

investigation.

It appeared that the interaction between the nucleus and the chemical substances

were only related to the physical factors and not to the chemical interaction.

It is convincingly proven that direct trauma to an intervertebral disc by needle

puncture can cause serious damage to the disc and that injection of radio-opaque

materials into the disc may also bring serious consequences.