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CHAPTER 26
paralysis of the skeletal muscles, there is at first a flaccid paralysis of the detrusor muscle
as well as the striated bladder muscles. Although the bladder wall, thanks to its autono
mous intramural innervation and its inherent elasticity, is not completely atonic, no
effective detrusor contractions are elicitable to overcome the passive blockage of the
vesical orifice. Therefore, retention of urine occurs. Voiding through overflow will take
place only when the maximum of expansibility of the bladder wall is reached and the
passive blockage of the bladder exit and that of the paralysed external urethral sphincter
are overcome by excessive intravesical pressure (ischuria paradoxa, overflow incontin
ence). If over-distension of the bladder is allowed to continue, long standing atonicity
of the bladder wall is inevitable, resulting in adverse effects on detrusor function once the
period of spinal shock has subsided.
The duration of the initial stages of bladder paralysis varies from 8 days to 6-8 weeks.
In complete lesions above the thoraco-lumbar junction, the duration of this stage
depends on various factors:
1
Hypotonicity of the bladder wall due to chronic habitual over-distension developed
previous to the spinal cord lesion.
2 Delayed development of reflex automatism of the isolated cord in upper thoracic and
cervical lesions not infrequently as a result of the degree of longitudinal damage of the
cord associated with its transverse lesion. In such cases the knee and ankle jerks may also
be diminished for longer periods than usual.
3 Age of the patient (in young individuals reflex micturition may occur within a few
days following complete transection of the cord).
4 Efficiency of the initial management of the bladder, in particular whether or not
over-distension during the stage of spinal shock and severe infection was avoided.
II. Stage of automatic or autonomous micturition
Once the stage of spinal shock has subsided, level and type of the cord or conus-cauda
equina lesion, whether complete or incomplete, are determining factors in the patho-
physiology of the bladder. A distinction has to be made between transverse lesions above
the thoraco-lumbar junction without damage to the spinal vesical centre and those where
this centre or its afferent and efferent nerve roots are involved either by direct destruction
(conus-cauda equina lesion) or by longitudinal damage associated with the transverse lesion
at higher level. These facts explain the great varieties of bladder dysfunction occurring
in spinal cord lesions. The following types of spinal cord bladder can be distinguished:
A. THE AUTOMATIC REFLEX BLADDER (SUPRA-NUCLEAR,
ALSO CALLED UPPER MOTOR NEURON TYPE)
EARLY AND INTERMEDIATE STAGES OF VESICAL REFLEX ACTIVITY
In complete transverse lesions above the lumbar-sacral segments, provided the reflex
arc has remained intact, reflex micturition develops as soon as the stage of spinal shock
has subsided and the isolated cord develops its automatic reflex function, unrestrained
