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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.

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The function assessments of the case groups. (a) Postoperative Majeed standards of two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS) with different types of vertical sacral fractures, respectively. (b) Statistical analysis of postoperative Majeed standards between two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS).
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Figure 7: The function assessments of the case groups. (a) Postoperative Majeed standards of two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS) with different types of vertical sacral fractures, respectively. (b) Statistical analysis of postoperative Majeed standards between two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS).

Mentions: Postoperative X-ray and CT scans demonstrated that both groups of patients achieved satisfactory reductions, and the PTMP and SIJS were fixed in satisfactory positions (Figure 1(b) and 1(c)). All 33 patients in two groups had no damage to blood vessels during the operation, showed no infection at the incision, no loosening or disruption of the internal fixation after operation, while their fractures all healed. However, in one patient of S group, the screw was fixed in the sacral foramina which injured the sacral nerve. The symptoms improved after screw replacement in revision surgery and drug use for the nutrient nerve. In two patients of S group, the screws were too short, but did not extract from the sacrum. Postoperative Majeed standards of the P group cases were between 62 and 93 points, with an average of 80.0 points. Within the total, there were six excellent cases, nine good cases, and two fair cases. The rate of excellent and good outcomes was 88.2%. Postoperative Majeed standards of the S group cases ranged from 71 to 94 points, with an average of 82.3 points. Within the total, there were six excellent cases, 10 good cases, and no fair cases. The excellent and good rate was therefore 100%. When percutaneous PTMP fixation cases including Denis I, II, III type sacral fractures and percutaneous SIJS fixation cases including Denis I, II type sacral fractures were compared, the postoperative Majeed standards, and the excellent and good rates of the two groups of clinical cases, did not demonstrate any statistically significant differences (P > 0.05), as can be seen in Figure 7.


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 function assessments of the case groups. (a) Postoperative Majeed standards of two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS) with different types of vertical sacral fractures, respectively. (b) Statistical analysis of postoperative Majeed standards between two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 7: The function assessments of the case groups. (a) Postoperative Majeed standards of two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS) with different types of vertical sacral fractures, respectively. (b) Statistical analysis of postoperative Majeed standards between two groups of clinical cases (percutaneous PTMP vs. percutaneous SIJS).
Mentions: Postoperative X-ray and CT scans demonstrated that both groups of patients achieved satisfactory reductions, and the PTMP and SIJS were fixed in satisfactory positions (Figure 1(b) and 1(c)). All 33 patients in two groups had no damage to blood vessels during the operation, showed no infection at the incision, no loosening or disruption of the internal fixation after operation, while their fractures all healed. However, in one patient of S group, the screw was fixed in the sacral foramina which injured the sacral nerve. The symptoms improved after screw replacement in revision surgery and drug use for the nutrient nerve. In two patients of S group, the screws were too short, but did not extract from the sacrum. Postoperative Majeed standards of the P group cases were between 62 and 93 points, with an average of 80.0 points. Within the total, there were six excellent cases, nine good cases, and two fair cases. The rate of excellent and good outcomes was 88.2%. Postoperative Majeed standards of the S group cases ranged from 71 to 94 points, with an average of 82.3 points. Within the total, there were six excellent cases, 10 good cases, and no fair cases. The excellent and good rate was therefore 100%. When percutaneous PTMP fixation cases including Denis I, II, III type sacral fractures and percutaneous SIJS fixation cases including Denis I, II type sacral fractures were compared, the postoperative Majeed standards, and the excellent and good rates of the two groups of clinical cases, did not demonstrate any statistically significant differences (P > 0.05), as can be seen in Figure 7.

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