Signs of injury to the vertebræ.—Separation of the spinous processes was often indicated by slight deformity, either evident or palpable, local pain, tenderness, mobility, and crepitus. In some cases these local signs were reinforced by evidence of cord injury. Fractures involving the laminæ differed merely in the degree to which the above signs were developed. Fractures of the transverse processes were generally only to be assumed from the position and direction of the wounds, the assumption being sometimes strengthened in probability by evidence of injury to the cord and nerves.
Fractures of the centra were also frequently only to be assumed from the direction of the wound tracks, and possibly from evidence of nerve injury. When no paralysis supervened, interference with the movements of the back, or pain, was so slight as to be inappreciable, especially in the presence of concurrent injury to other parts, which was seldom absent. I only once saw any angular deformity from this injury, and that slight, and not apparent before the end of three weeks. In this particular a very striking difference exists between injuries from small-calibre bullets and larger ones such as the Martini-Henry. In the only instance of Martini-Henry fracture of the spine that came under my notice, the centrum was severely comminuted and deformity was obvious. Still, as in so many particulars, the difference was only one of degree, since comminution of the centra in gunshot wounds has always been observed to be slight in nature compared with what is met with in the compression fractures of civil life.
A few words will suffice to dismiss the questions of diagnosis, prognosis, and treatment of the above injuries. The diagnosis depended on attention to the signs above indicated, the prognosis almost entirely on the concurrent injury to the nervous system, which will be considered later, and the treatment consisted in enforcing rest alone.
Injuries to the Spinal Cord accompanying Small-calibre Bullet Wounds of the Vertebræ
Anatomical lesions.—In introducing the subject of the nature of the lesions of the spinal cord and membranes, I should again enforce the statement that their character and degree, in comparison with the slight accompanying bone damage, are pathognomonic of gunshot wounds, and that these characters find their completest exemplification in injuries produced by bullets of small calibre, endowed with a high grade of velocity. Again, that the varying degrees of damage depend comparatively slightly on the position of the bone lesion, apart from actual encroachment on the canal, while the degree of velocity retained by the bullet at the moment of impact is all-important. In no other way are the divergent results to be explained which follow an apparently identical injury, in so far as extent, position, and external evidence of damage to the spinal column are concerned.
Injuries to the nerve roots of the nature of concussion and contusion, are dealt with in Chapter IX.
Pure concussion of the spinal cord may, I believe, be studied from a better standpoint in the case of small-calibre bullet injuries than in any others, since in many instances it is, I think, possible to exclude any complications such as wrenches and strains of the vertebral column, and ascribe the symptoms to the pure effect of extreme vibratory force communicated to the cord by its enveloping bony canal. The condition must be considered under the two headings of slight and severe.
In slight concussion the usually transient effects of the injury, and its happy tendency not to destroy life, place us in a state of uncertainty as to the occurrence of anatomical changes, since no opportunity of post-mortem examination occurred. The clinical condition included under this term corresponds with that implied in 'spinal concussion' in civil practice. One point of extreme interest, whether the subjects of small-calibre bullet spinal concussion will in the future suffer from the remote effects common to similar sufferers in civil life from other causes such as railway collisions, still remains for future determination. An ample field for such observations has at any rate been created by the present war.
In severe concussion a far more highly destructive action is exerted. This condition may be followed by complete disorganisation of the cord, accompanied or not by multiple parenchymatous hæmorrhages into its substance. Either or both of these pathological conditions are produced by the impact of the bullet with the spine, given a sufficiently high degree of velocity, and it is difficult to separate clinically the resulting symptoms. This is a matter perhaps of less importance, since it stands to reason that a vibratory force, capable of rupturing the spinal capillaries, would at the same time damage the nervous tissue.
In speaking of concussion of this degree, it should be clearly recognised that a general condition, such as is indicated by the use of the term 'concussion of the brain,' is in no wise implied. The condition is really far more nearly allied to one of contusion, a strictly localised portion of the spinal cord undergoing the destructive process which affects the segments below only in so far as it interrupts the normal channels of communication with the higher centres.