| Objectives:1.Constructing the piglet models of novel low-profile growth-inducing system and dual growing rods system to compare the effects of the novel low-profile growth-inducing system and the dual growing rods system on the growth performance of spine.2.Compare the effects of the novel low-profile growth-inducing system and the dual growing rods system on the growth and development of the intervertebral disc,vertebral body,spinal canal and pedicle of piglet.Methods:1.Establishing the piglet models of the novel low_profile growth-inducing system and the dual growing rods system to observe their effects on the growth performance of spine.18 piglets(6-week old,female)were randomly divided into A,B,C groups of 3,each group of 6.Group A:the novel low-profile growth-inducing system was implanted.Fisheye nails were implanted on both sides of T5-T6,T15-L1.Gland double ear nails were implanted on both sides of T10 and T11.The appropriate length of titanium rod was pre-bended according to sagittal kyphosis angle,and the titanium rod was connected with fisheye nails through subcutaneous intermuscular penetration technique.After adjusting the force line of titanium rod,the Gland double ear nails on both sides of T10-T11 segment were locked and fixed.The appropriate length of titanium rod was reserved on both sides of head and tail for sliding of titanium rod.The fisheye nails at T5-T6 and T15-L1 segments could allow the titanium rod to slide with the growth of spine.Group B:the dual growing rods system was implanted.Traditional universal pedicle screws were implanted on both sides of T5-T6,T15-L1.The appropriate length of titanium rod was pre-bended according to sagittal kyphosis angle.After adjusting the force line of the titanium rod,the titamium rod was connected with a domino connector and reserved the appropriate length of the titanium rod.The titanium rods will be stretched out at the 3rd,6th and 9th week after operation.Group C:control group,bilateral articular processes of T5-T6,T10-T11 and T15-L1 were exposed unilaterally without screw placement.X and CT scans were performed on three groups of piglet models on the day after operation and 3rd month after operation respectively.Observing the fusion of the facet joints,Measuring the length of T5-L1 and its growth value.The total operative time,operation times and intraoperative blood loss were calculated and analyzed statistically.2.Effects of the novel low-profile growth-inducing system and the dual growing rods system on the growth and development of vertebral body,spinal canal,pedicle and intervertebral disc in piglets:dividing the vertebral bodies(T5-L1)based on the intervention segment into 3 groups.Intervened vertebrae 1:T5-T6,T15-L1(group A with fisheye screws,group B with traditional universal pedicle screws).Intervened vertebrae 2:(group A with gland double ear nails,group B without screw,but titanium rods with donino connection).Intervened vertebrae 3:T7-T9,T12-T14(all without screw).Intervertebral discs were also divided into three groups.Discs 1:T5/T6,T15/L1;Discs 2:T10/T11;Discs 3:T6-T10,T11-T15.CT scans were performed on three groups of piglet models on the day after operation and 3rd month after operation respectively.The HVB,TDVB,APDB,TDVC,APDC,PedW,TL,PedH and the average height of disc were measured and analyzed statistically.Results;1.Three groups of piglet models were successfully established.A and B groups of screws and titanium rods were well connected without screw loosening,rod breaking and nail pulling.1 pig of the dual growing rods group had superficial infection nearby the domino connector on the third day after the third distraction.After the debridement,iniection was controlled and the wound healed.The rest of the piglets successfully completed the experiment.After awake,piglets could walk freely without any complications such as claudication and paralysis.hn group A,there were 6 operations in 6 piglets.24 operations were performed in 6 piglets in group B(except a debridement).The average operation time of each piglets in group A was 130.83±13.19min.The average operation time of each piglets in the B group was 186.67±32.50min.The average blood loss in group A was 54.17±4.92ml,and the average blood loss in group B was 96.67±5.16ml.The average operation time and average blood loss in group B were larger than those in group A,and the difference was significant(P<0.05).At 3rd month after operation,in the intervention segment of the novel low-profile growth-inducing system group,there was no obvious degeneration and fusion in the articular space of the facet joint;in the intervention segment of the dual growing rods system group,multiple facet osteophytes were formed and the facet joints were fused.There was no significant difference in the length of T5-L1 spine between groups A,B and C on the day after operation(P>0.05).At 3rd month after operation,the length of T5-L1 segment in group A was 31.92±0.61cm with a growth value of 7.56±1.30 cm;the length of T5-L1 segment in group B was 32.14±1.15cm with a growth value of 7.21±1.63cm;and the length of T5-L1 segment in group C was 34.13±0,29cm with a growth value of 10.55±0.41cm.There was no significant difference in the length and growth value of T5-L1 spine between group A and group B(P>0.05).The length and growth value of T5-L1 spine in group A and B were lower than those in group C(P<0.05).2.On the day after operation,there were no significant differences in the average height of disc,vertebral body related parameters(HVB,TDVB and APDB),spinal canal related parameters(TDVC and APDC),pedicle related parameters(PedWs TL and PedH)between the three groups(P>0.05).3.At 3rd month after operation,Discs 1:The average height of intervertebral disc in group A was higher than that in group B(P<0.05).There was no significant difference between group A and group C(P>0.05).The average height of intervertebral disc in group B was lower than that in group C(P<0.05).There was no significant difference in the average height of intervertebral disc between groups A,B and C(P>0.05)for disc 2(T10/T11)and disc 3(T6-T10,T11-T15).4.At 3rd month after operation,Intervened vertebrae 1(T5-T6,T15-L1):There was no significant difference in TDVB,APDB,TDVC,APDC,PedW,TL,PedH between group A and group C(P>0.05),but HVB in group A was smaller than that in group C(P<0.05);TDVB,APDB,PedW,PedH in group B were not significantly different from those in group C(P>0.05),while HVB,TDVC,APDC and TL in group B were smaller than those in group C(P<0.05).There was no significant difference in HVB,TDVB,APDB,PedW,PedH between group A and group B(P>0.05).TDVC,APDC and TL in group A were larger than those in group B,and the difference was statistically significant(P<0.05).Intervened vertebrae 2(T10-T11):There was no significant difference in TDVB,APDB,TDVC and TL between group A and group C(P>0.05),but HVB,APDC,PedW and PedH in group A were smaller than those in group C(P<0.05);HVB,APDB,TDVB,TDVC,APDC,PedW,TL,PedH in group B were not significantly different from those in group C(P>0.05);TDVB,APDB,TDVC and PedH in group A were not significantly different from those in group B(P>0.05).HVB,APDC,PedW and PedH in group A were less than those in group B,and the difference was statistically significant(P<0.05).Intervened vertebrae 3(T7-T9,T12-T14):There was no significant difference in APDB,TDVB,TDVC,APDC,PedW,TL,PedH between group A and group C(P>0.05).HVB in group A was smaller than that in group C,with statistical significance(P<0.05).There was no significant difference in APDB,TDVB,TDVC,APDC,PedW,TL,PedH between group B and group C(P>0.05).HVB in group B was smaller than that in group C,with statistical significance(P<0.05).There was no significant difference in HVB,APDB,TDVB,TDVC,APDC,PedW,TL,PedH between group A and group B(P>0.05).Conclusions:1.The novel low-profile growth-inducing system allowed the growth of piglet’s spine and had similar growth efficiency with the dual growing rods system.Although both of them hinder the growth of the spine to some extent,the novel low-profile growth-inducing system has less operation times,shorter operation time,less intraoperative bleeding and no obvious fusion of the facet joints,which is more advantageous than the dual growing rods system requiring repeated stretching and lengthening operation.2.For the disc 1:the dual growing rods system hindered the growth of the average height of the intervertebral disc,while the novel low-profile growth-inducing system had no significant effect on the growth of the average height of the intervertebral disc;for disc 2 and disc 3:the novel low-profile growth-inducing system and the dual growing rods system had no obvious effect on the average height growth and development of the intervertebral disc in piglets.3.Intervened vertebrae 1:The novel low-profile growth-inducing system had no significant effect on the growth and development of TDVB,APDB,TDVC,APDC,PedW,TL and PedH,but had some hindrance on the growth and development of HVB;the dual growing rods system had no significant effect on the growth and development of TDVB,APDB,PedW and PedH,and had some hindrance on the growth and development of HVB,TDVC,APDC and TL.The novel low-profile growth-inducing system has less effect on the growth and development of TDVC,APDC and TL than the dual growing rods system.4.Intervened vertebrae 2:The novel low-profile growth-inducing system had no significant effect on the growth and development of TDVB,APDB,TDVC and TL,but had some hindrance on the growth and development of HVB,APDC,PedW and PedH.The dual growing rods system had no significant effect on the growth and development of HVB,APDB,TDVB,TDVC,APDC,PedW,TL and PedH.The growth and development of HVB,APDC,PedW and PedH were less affected by the dual growing rods system than by the novel low-profile growth-inducing system.5.Intervened vertebrae 3:The growth and development of APDB,TDVB,TDVC,APDC,PedW,TL and PedH were not significantly affected by the novel low-profile growth-inducing system and the dual growing rods system,and the growth and development of HVB were inhibited. |
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