Mamillary and spinous process base wiring did not improve L5-L6 posterolate
ral fusion rate, stiffness, or strength in a previously established rabbit
model. Specimen radiography significantly underestimated fusion rate when c
ompared with manual palpation (37% versus 68%), Fused specimens were signif
icantly stiffer (67.2 N/mm versus 41.1 N/mm) and stronger (177 N versus 121
N) in tension than were nonfused specimens. Deep wound infection, detected
only at the time of sacrifice, apparently was more common with internal fi
xation (43% versus 21%), Noninfected specimens were significantly stiffer (
63.3 N/mm versus 43.0 N/mm) and stronger (176 N versus 107 N) than were inf
ected specimens.