Abstract:Background: Distraction osteogenesis (DO) is an approach for bone lengthening and reconstruction. The pixel value ratio (PVR), an indicator calculated from X-ray images, is reported to assess the final timing for the external fixator removal. However, the early PVR and its potential influencing factors and the relationship between the early PVR and clinical outcomes are rarely discussed. Therefore, this study was employed to address these issues.Methods: A total of 125 patients with bone lengthening were inves… Show more
“…Balakumar et al [13] found that PVR may be a reliable indicator of bone graft fusion to aid clinical decision by measuring and analyzing PVR of bone grafts in 30 patients. Some studies have shown gender differences in adults, and Liu et al [1] studied the gender of long bone lengthening and found no signi cant difference which is consistent with our study, and there was no difference in PVR between the genders of children. For the effect of obesity or weight on BMD, Garvey [14] et al concluded that there is an effect in adults, with a signi cant negative correlation between obesity and BMD (β = -0.003).…”
Section: Discussionsupporting
confidence: 92%
“…Distraction osteogenesis (DO) is a technique for regeneration of bone, it stimulates bone tissue regeneration and reconstruction by giving the bone tissue a tension of stretching. The pixel-to-value ratio (PVR) is a metric measured by x-ray images that has been used in many studies to assess the time of nal external xator removal [1] [2]. However, all of this studies only describes its in uence after long bone lengthening [3].…”
Background
the aim of this study was to investigate the value and potential influencing factors of pixel value ratio (PVR) in early phase of mandible healing by distraction osteogenesis.
Methods
We performed a retrospective analysis on 342 patients with bilateral mandibular lengthening surgery, measured PVRs in osteotomy position of children before surgery, and monitored PVRs in early stage of bone regenerating at 1st, 2nd and 3rd month respectively after surgery. The potential effects of gender, weight, and age on fixation period were also analyzed.
Results
PVRs before osteotomy and at 1st, 2nd and 3rd month after osteotomy were (R0.96 ± 0.04, L0.97 ± 0.05), (R0.4 ± 0.1, L0.42 ± 0.1), (R0.68 ± 0.11, L0.71 ± 0.11), (R0.97 ± 0.04, L0.98 ± 0.04) which had significant differences (p < 0.001). We found no significant difference in PVRs by gender. In terms of age, there was a significant difference in PVRs between children aged less than 28 days and older than 120 days before surgery. There were also significant differences between those aged less than 28 days and older than 120 days, and children aged 8–28 days and aged 29–60 days at the 3rd month after surgery. Consider weight, children with birth weight less than 4 kg and those with admission weight less than 2.5 kg were significant different.
Conclusion
PVRs were gradually increased during the early 3 months after the osteotomy. Gender had no effect on PVRs, while age, birth weight, and admission weight had a greater effect. Our results may inform the assessment of PVRs and potential impact of patients with early bone lengthening.
“…Balakumar et al [13] found that PVR may be a reliable indicator of bone graft fusion to aid clinical decision by measuring and analyzing PVR of bone grafts in 30 patients. Some studies have shown gender differences in adults, and Liu et al [1] studied the gender of long bone lengthening and found no signi cant difference which is consistent with our study, and there was no difference in PVR between the genders of children. For the effect of obesity or weight on BMD, Garvey [14] et al concluded that there is an effect in adults, with a signi cant negative correlation between obesity and BMD (β = -0.003).…”
Section: Discussionsupporting
confidence: 92%
“…Distraction osteogenesis (DO) is a technique for regeneration of bone, it stimulates bone tissue regeneration and reconstruction by giving the bone tissue a tension of stretching. The pixel-to-value ratio (PVR) is a metric measured by x-ray images that has been used in many studies to assess the time of nal external xator removal [1] [2]. However, all of this studies only describes its in uence after long bone lengthening [3].…”
Background
the aim of this study was to investigate the value and potential influencing factors of pixel value ratio (PVR) in early phase of mandible healing by distraction osteogenesis.
Methods
We performed a retrospective analysis on 342 patients with bilateral mandibular lengthening surgery, measured PVRs in osteotomy position of children before surgery, and monitored PVRs in early stage of bone regenerating at 1st, 2nd and 3rd month respectively after surgery. The potential effects of gender, weight, and age on fixation period were also analyzed.
Results
PVRs before osteotomy and at 1st, 2nd and 3rd month after osteotomy were (R0.96 ± 0.04, L0.97 ± 0.05), (R0.4 ± 0.1, L0.42 ± 0.1), (R0.68 ± 0.11, L0.71 ± 0.11), (R0.97 ± 0.04, L0.98 ± 0.04) which had significant differences (p < 0.001). We found no significant difference in PVRs by gender. In terms of age, there was a significant difference in PVRs between children aged less than 28 days and older than 120 days before surgery. There were also significant differences between those aged less than 28 days and older than 120 days, and children aged 8–28 days and aged 29–60 days at the 3rd month after surgery. Consider weight, children with birth weight less than 4 kg and those with admission weight less than 2.5 kg were significant different.
Conclusion
PVRs were gradually increased during the early 3 months after the osteotomy. Gender had no effect on PVRs, while age, birth weight, and admission weight had a greater effect. Our results may inform the assessment of PVRs and potential impact of patients with early bone lengthening.
“…Our previous study has shown that the early PVR was moderately negatively associated with HI and LI, which suggests that the early PVR can effectively reflect the clinical outcome of DO (16). However, the four cortices were taken as a whole.…”
AimsWe aimed to explore the associations of the early PVR in four cortices with Healing Index (HI), Lengthening Index (LI), and External Fixator Index (EFI) in the bone union and non-union groups.MethodsA total of 52 patients, including 39 bone union and 13 bone non-union subjects, were recruited in this study. The general characteristics and PVR in four cortices in each group were explored. Afterward, the early PVR in four cortices, including medial, lateral, anterior, and posterior sides, were compared. Finally, the associations of the early PVR in four cortices with HI, LI, and EFI were also investigated.ResultsThe general characteristics of these patients were consistent, except for HI (31.54 ± 12.24 vs. 45.08 ± 27.10, P = 0.018) and EFI (57.63 ± 18.15 vs. 71.29 ± 24.60, P = 0.046). The growth of regenerated callus was asymmetrical in the bone union group (the posterior PVR seems to grow faster), whereas no statistical difference was obtained in the bone non-union group. Furthermore, the posterior PVR in the bone union group was significantly higher than that in the bone non-union group (the first month: 0.96 ± 0.17 vs. 0.86 ± 0.06, p = 0.047; the second month: 0.98 ± 0.14 vs. 0.89 ± 0.09, p = 0.041; the third month: 1.00 ± 0.12 vs. 0.92 ± 0.09, p = 0.039). Most importantly, the posterior PVR was inversely associated with HI, LI, and EFI (the first month: r = −0.343, p = 0.041; r = −0.346, p = 0.042; r = −0.352, p = 0.041; the second month: r = −0.459, p = 0.004; r = −0.277, p = 0.101; r = −0.511, p = 0.002; the third month: r = −0.479, p = 0.003; r = −0.398, p = 0.018; r = −0.551, p = 0.001) in the bone union group, respectively. However, this finding was lost in the bone non-union group.ConclusionThe early posterior cortex PVR seems to grow faster than the medial, lateral, and anterior sides in the bone union group, which represents an asymmetrical development pattern. Moreover, the posterior cortex PVR was negatively associated with HI, LI, and EFI, respectively. The posterior cortex PVR may be a novel and reliable detection index in the process of DO.
“…Moreover, the early PVR seemed to be moderately inversely associated with HI and LI, respectively. In another word, the early PVR of callus may partly reflect the potential clinical outcome for DO [ 25 ]. On the basis of these above, our study further figured out the PVR growth pattern in bone nonunion during DO.…”
Section: Discussionmentioning
confidence: 99%
“…Then, the ratio of the regenerated callus PV to the adjacent bone PV was calculated. The higher PVR indicated that the regenerated callus was closer to the reference bone, whereas the lower PVR reflected a lower immaturity of the callus [ 17 , 25 ]. The formula for the calculations of PVR were as follows: Fig.…”
Background
The clinical characteristics of bone nonunion during distraction osteogenesis (DO) were rarely discussed. This study was employed to specify the difference between bone union and nonunion during DO.
Methods
The patients with bone lengthening were recruited in our study. The bone union cases indicated the ones that remove the external fixator successfully, whereas the bone nonunion represented the bridging callus did not appear even after 9 months (an absence of bridging callus for at least three out of four cortices on plain radiographs) that needs autogenous bone transplantation. The differences in the pixel value ratio (PVR) growth of regenerated callus, lengthening index (LI), healing index (HI), external fixation index (EFI) and blood biochemical indexes between bone union and nonunion were analyzed.
Results
A total of 8 bone nonunion and 27 bone union subjects were included in this study. The PVR growth in bone nonunion was significantly lower than that in bone union (0.19 ± 0.06 vs. 0.32 ± 0.16, P = 0.048). Interestingly, the HI and EFI in bone nonunion was significantly higher than that in bone union (62.0 ± 31.4 vs. 37.0 ± 27.4, P = 0.036; 75.0 ± 30.9 vs. 49.9 ± 16.1, P = 0.006). However, no significant difference with regard to LI was identified (0.76 ± 0.52 vs. 0.77 ± 0.32, P = 0.976). Moreover, the circulating level of urea and lymphocyte count in bone union was significantly lower than that in bone nonunion (4.31 ± 1.05 vs. 5.17 ± 1.06, P = 0.049; 2.08 ± 0.67 vs. 2.73 ± 0.54, P = 0.018). On the contrary, the circulating level of magnesium in bone union was significantly higher than that in bone nonunion (0.87 ± 0.07 vs. 0.80 ± 0.07, P = 0.014).
Conclusion
Compared to the bone union, the PVR growth was significantly lower, whereas the HI and EFI was significantly higher in the bone nonunion. Moreover, the circulating level of urea, magnesium and lymphocyte count was also different between these two. Therefore, the PVR, HI and EFI seems to be reliable and sensitive indicators to reflect the bone nonunion during DO, which might be considered in bone lengthening. Further prospective studies are still needed to elaborate the concerned issues.
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