Figure 29: Comparison between changes in secondary muscle spindle afferent activity and detrusor pressure (measured before the surgery; for the implantation of a sacral anterior root stimulator). Paraplegic 9.
A. Activity changes of the afferent fi ber SP2(1) following bladder catheter pulling (Figure 37Ba). Approx. mean activity level is represented by a dashed line at 7.5 IIs/0.8s ((APs -1)/0.8s). The activity above the mean is cross-hatched and is proposed to be due to parasympathetic activation. Root vS4.
B. Detrusor pressure (pressure difference) changes taken from ‘C’. Note that changes in the detrusor pressure show almost exactly the same time course as do the activated changes of the secondary muscle spindle afferent fi ber SP2(1) of ‘A’. Corresponding peaks are correlated by arrows.
C. Abdominal pressure (measured as rectal pressure), intravesical pressure (urinary bladder pressure) and detrusor pressure (pressure difference) during retrograde fi lling before the surgery. One transient detrusor pressure increase, marked ‘B’, is used, after enlargement in ‘B’, to compare with the spindle afferent activity.