Limits...
Parallel analysis of finite element model controlled trial and retrospective case control study on percutaneous internal fixation for vertical sacral fractures.

Chen H, Wu L, Zheng R, Liu Y, Li Y, Ding Z - BMC Musculoskelet Disord (2013)

Bottom Line: Accordingly, the high values of the maximum displacements/stresses of the plate-fixation model group approximated those of the screw-fixation model group.However, further simulation of Denis I, II and III type fractures in each group of models found that the biomechanics of the plate-fixation models became increasingly stable and compatible, whereas the biomechanics of the screw-fixation models maintained tiny fluctuations.When treating Denis III fractures, the biomechanical effects of the pelvic ring of the plate-fixation model were better than the screw-fixation model.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Orthopedics, Yiwu Central Hospital, Wenzhou Medical College, Yiwu 322000, China.

ABSTRACT

Background: Although percutaneous posterior-ring tension-band metallic plate and percutaneous iliosacral screws are used to fix unstable posterior pelvic ring fractures, the biomechanical stability and compatibility of both internal fixation techniques for the treatment of Denis I, II and III type vertical sacral fractures remain unclear.

Methods: Using CT and MR images of the second generation of Chinese Digitized Human "male No. 23", two groups of finite element models were developed for Denis I, II and III type vertical sacral fractures with ipsilateral superior and inferior pubic ramus fractures treated with either a percutaneous metallic plate or a percutaneous screw. Accordingly, two groups of clinical cases that were fixed using the above-mentioned two internal fixation techniques were retrospectively evaluated to compare postoperative effect and function. Parallel analysis was performed with a finite element model controlled trial and a case control study.

Results: The difference of the postoperative Majeed standards and outcome rates between two case groups was no statistically significant (P > 0.05). Accordingly, the high values of the maximum displacements/stresses of the plate-fixation model group approximated those of the screw-fixation model group. However, further simulation of Denis I, II and III type fractures in each group of models found that the biomechanics of the plate-fixation models became increasingly stable and compatible, whereas the biomechanics of the screw-fixation models maintained tiny fluctuations. When treating Denis III fractures, the biomechanical effects of the pelvic ring of the plate-fixation model were better than the screw-fixation model.

Conclusions: Percutaneous plate and screw fixations are both appropriate for the treatment of Denis I and II type vertical sacral fractures; whereas percutaneous plate fixation appears be superior to percutaneous screw fixation for Denis III type vertical sacral fracture. Biomechanical evidence of finite element evaluations combined with clinical evidence will contribute to our ability to distinguish between indications that require plate or screw fixation for vertical sacral fractures.

Show MeSH

Related in: MedlinePlus

The distribution nephogram of displacements/stresses. The representative distributions of (a) the sum displacements and (b) von Mises stresses in two surgical FE models with Denis III type fractures (PTMP vs. SIJS) both under flexion states.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3750865&req=5

Figure 6: The distribution nephogram of displacements/stresses. The representative distributions of (a) the sum displacements and (b) von Mises stresses in two surgical FE models with Denis III type fractures (PTMP vs. SIJS) both under flexion states.

Mentions: Finally, in fractured sacral zones I, II or III, the displacement distributions and the stress distributions in the posterior pelvic ring of the P-fixation models all showed progressive symmetry, whereas the S-fixation models had no symmetry. Moreover, the peak von Mises stresses of the sacral fracture surfaces of P-fixation models were obviously lower than those of S-fixation models. The most obvious symmetry emerged at sacrum zone III fractures of the P-fixation models, as shown in Figure 6.


Parallel analysis of finite element model controlled trial and retrospective case control study on percutaneous internal fixation for vertical sacral fractures.

Chen H, Wu L, Zheng R, Liu Y, Li Y, Ding Z - BMC Musculoskelet Disord (2013)

The distribution nephogram of displacements/stresses. The representative distributions of (a) the sum displacements and (b) von Mises stresses in two surgical FE models with Denis III type fractures (PTMP vs. SIJS) both under flexion states.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750865&req=5

Figure 6: The distribution nephogram of displacements/stresses. The representative distributions of (a) the sum displacements and (b) von Mises stresses in two surgical FE models with Denis III type fractures (PTMP vs. SIJS) both under flexion states.
Mentions: Finally, in fractured sacral zones I, II or III, the displacement distributions and the stress distributions in the posterior pelvic ring of the P-fixation models all showed progressive symmetry, whereas the S-fixation models had no symmetry. Moreover, the peak von Mises stresses of the sacral fracture surfaces of P-fixation models were obviously lower than those of S-fixation models. The most obvious symmetry emerged at sacrum zone III fractures of the P-fixation models, as shown in Figure 6.

Bottom Line: Accordingly, the high values of the maximum displacements/stresses of the plate-fixation model group approximated those of the screw-fixation model group.However, further simulation of Denis I, II and III type fractures in each group of models found that the biomechanics of the plate-fixation models became increasingly stable and compatible, whereas the biomechanics of the screw-fixation models maintained tiny fluctuations.When treating Denis III fractures, the biomechanical effects of the pelvic ring of the plate-fixation model were better than the screw-fixation model.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Orthopedics, Yiwu Central Hospital, Wenzhou Medical College, Yiwu 322000, China.

ABSTRACT

Background: Although percutaneous posterior-ring tension-band metallic plate and percutaneous iliosacral screws are used to fix unstable posterior pelvic ring fractures, the biomechanical stability and compatibility of both internal fixation techniques for the treatment of Denis I, II and III type vertical sacral fractures remain unclear.

Methods: Using CT and MR images of the second generation of Chinese Digitized Human "male No. 23", two groups of finite element models were developed for Denis I, II and III type vertical sacral fractures with ipsilateral superior and inferior pubic ramus fractures treated with either a percutaneous metallic plate or a percutaneous screw. Accordingly, two groups of clinical cases that were fixed using the above-mentioned two internal fixation techniques were retrospectively evaluated to compare postoperative effect and function. Parallel analysis was performed with a finite element model controlled trial and a case control study.

Results: The difference of the postoperative Majeed standards and outcome rates between two case groups was no statistically significant (P > 0.05). Accordingly, the high values of the maximum displacements/stresses of the plate-fixation model group approximated those of the screw-fixation model group. However, further simulation of Denis I, II and III type fractures in each group of models found that the biomechanics of the plate-fixation models became increasingly stable and compatible, whereas the biomechanics of the screw-fixation models maintained tiny fluctuations. When treating Denis III fractures, the biomechanical effects of the pelvic ring of the plate-fixation model were better than the screw-fixation model.

Conclusions: Percutaneous plate and screw fixations are both appropriate for the treatment of Denis I and II type vertical sacral fractures; whereas percutaneous plate fixation appears be superior to percutaneous screw fixation for Denis III type vertical sacral fracture. Biomechanical evidence of finite element evaluations combined with clinical evidence will contribute to our ability to distinguish between indications that require plate or screw fixation for vertical sacral fractures.

Show MeSH
Related in: MedlinePlus