C- DISLOCATIONS OF THE VERTEBRAL COLUMN
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his own further experiences and the data given from other workers in this field, the risk
of laminectomy in causing death, in particular in tetraplegics, or producing irreversible
damage of the cord is too great to consider this procedure as suitable in the immediate
management of injuries of the spinal cord and cauda equina.
Prevention of post-traumatic necrosis of the spinal cord
(a) Cooling the spinal cord at the site of injury
Experiments have been carried out for some time on this subject by Dr R.M.White
of the Department of Neurosurgery at Case Western Reserve University School of
Medicine in Cleveland. He reported his results at a Congress of Neurological Surgeons
in Denver 1972 (reported in the
Medical World News,
10 November 1972).
The underlying theory is to reverse, at least partially, the effect of cord injury by
cooling the cord to prevent the development of post-traumatic necrosis initiated by the
trauma. It is assumed that there is a definite time lag before the process of necrosis is
fully developed and that during this time the long fibre pathways are mostly intact.
Therefore, if this process can be stopped in the acute stage, then useful spinal cord func
tion can be preserved. This theory is contrary to the generally held opinion that the spinal
function is immediately and permanently lost following traumatic disruption of the cord.
The patient has to be treated within 4 to 6 hr after injury, which in itself seriously
restricts the use of this method. The technique consists in performing a standard lami
nectomy, removing three laminae of the injured site. When the dura is exposed and the
cord is found to be so swollen or displaced that it is impinging on the dura, it is recom
mended that the dura must be cooled for an hour before it is opened. Following opening
of the dura, tubes are placed above and below the lesion, which are connected to a heat
exchanger and the fluid pumped with an ordinary heart-lung machine. The wound
is then slowly filled with ice-cold normal saline until the pump moves the cold fluid
through the system to the heat exchanger and back to the wound. A high flow-rate of
500 ccs to 1,000 ccs per minute is established. Temperature measurements in the muscles
of the wound near the cord are made and kept to less than 20°C. The cooling is continued
for 3 hr, then the dura is left open and the muscles, fascia and skin are closed in the
usual way.
Ten patients with cervical cord injuries and tetraplegia were reported. However,
according to Dr White they were not an 'ideal group'. Five of these patients underwent
an emergency laminectomy and were treated with 3 hr of direct cord cooling. Only
three had some return of neurological function in the lower limbs and in two of these
the return of function was marked. No exact details about the clinical symptomatology
before and after cooling were given. Moreover, three of the untreated patients also had
some significant improvement in the upper limbs. Dr White himself came to the conclusion
that 'Unfortunately no definite study has yet been published that absolutely establishes
that direct cooling of the spinal cord is in fact beneficial'. Moreover, in my opinion, the
theoretical basis of the theory is not yet proven by systematic histological findings. It
must be pointed out—and the three untreated patients are a clear proof—that spinal
