A biomechanical comparison was conducted on two internal spinal fixation techniques: pins
and Polymethylmethacrylate, and the String of Pearls Interlocking Plate System. Both
techniques were applied to a surgically simulated level L7-S1 complete spinal injury, with the
objective of the study being to compare the stability of the two techniques. Cadaver
specimens from 18 skeletally mature large breed dogs were used. These specimens were
randomly divided into two equal groups and fixated using one of the two internal spinal
The lumbosacral spine specimens (L5-S3) were subjected to a mechanically applied
bending moment, which was applied to the caudal and cranial ends of the specimen.
Biomechanical parameters including range of motion (RoM), neutral zone (NZ), and elastic
zone stiffness (EZS) were used to compare the stability of the two fixation techniques. No
significant difference between the means of the NZ in flexion (p-value=0.3458), extension (pvalue=
0.1255), and the total value (p-value = 0.3458) of the injured lumbosacral (L7-S1) joint
fixated with the two fixation techniques was found. Similarly, no significant difference
between the means of the RoM in flexion (p-value = 0.2386) and extension (p-value =
0.1255), or between the means of the EZS in extension (p-value = 0.4094) was noted.
Therefore, it can be concluded that the stability of the injured joint between the two fixation
techniques is similar.