Reliability Study And Preliminary Clinical Application Of The Upper Line Of Posterior Superior Iliac Spine Based On CT Three-Dimensional Reconstruction As A New Localization Marker For Lumbar Vertebral Segments

Objective:The most commonly used method for locating lumbar segments is the intercristal line method,which is the line connecting the highest point of the bilateral iliac crest.The operator locates the L4/L5intervertebral space according to the highest point of the bilateral iliac crest.However,previous studies have found that the location distribution of the intercristal line is affected by the patient’s age,sex,body fat rate and other factors,and the localization accuracy is limited.Segmental localization of lumbar vertebrae is very important in minimally invasive surgery.Intercristal line method often requires C-arm fluoroscopy to verify localization,which is not only time-consuming but also increases radiation exposure of patients and doctors.We found a new method to locate the interspinous space of L5-S1 according to the upper line of posterior superior iliac spine(1.5cm above the vertex of posterior superior iliac spine).This study compared the reliability of lumbar segmental localization between the upper line of posterior superior iliac spine and the intercristal line.The study included two parts:imaging study based on three-dimensional reconstruction of CT and clinical study.Part I:Imaging analysis of the upper line of posterior superior iliac spine based on CT three-dimensional reconstruction in the localization of lumbar segments.To compare the consistency between the upper line of posterior superior iliac spine and the intercristal line and the corresponding spinous process space on the three-dimensional model of lumbar spine and pelvis after CT three-dimensional reconstruction.To explore the feasibility of upper line of posterior superior iliac spine in lumbar segmental localization.Part II:The clinical application research of the upper line of posterior superior iliac spine in the positioning of lumbar segments before minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF).To analyze the reliability and clinical value of the upper line of posterior superior iliac spine in the positioning of lumbar segments.Methods:Part I:A retrospective analysis of 248 patients who underwent lumbar 64 row CT in Henan Provincial People’s Hospital from October 2019 to December 2020,including 118 males and 130 females,with an average age of(48.5±15.4)years.The original CT data of the patients were imported into the Bao Hulu operation simulation software for three-dimensional reconstruction of lumbar vertebrae and pelvis.After marking the lines on the posterior superior iliac spine and the line between the iliac crest on both sides in the three-dimensional model,switch to the X-ray mode,and observe the position distribution of the line between the posterior superior iliac spine and the line between the iliac crest.After marking the upper line of posterior superior iliac spine and the intercristal line on both sides in the three-dimensional model,switch to X-ray mode.The position distribution of the upper line of posterior superior iliac spine and the intercristal line were observed and compared.Part II:84 patients with lumbar degenerative diseases treated by single segment MIS-TLIF in Henan Provincial People’s Hospital from January 2021 to February 2022 were selected.According to the way of preoperative body surface positioning,the patients were randomly divided into experimental group and control group.There were 43 patients in the experimental group,male/female(19/24 cases),aged 54.3±12.4 years.The upper line of posterior superior iliac spine was used to locate the lumbar segment before operation.There were 41 patients in the control group,male/female(20/21 cases),aged 52.8±11.5 years.The intercristal line was used to locate the lumbar segment before operation.X-ray,CT and MRI of lumbar vertebrae were taken routinely before operation in all patients,and single-segment MIS-TLIF was performed in both groups.Record and compare the accuracy of the first localization(the number of patients who successfully located the lumbar segment for the first time/the total number of patients in this group×100%),preoperative location time,location fluoroscopy times and incision length between the two groups.The visual analogue scale(VAS)of pain and Oswestry disability index(ODI)were recorded before and 3days after operation to evaluate the curative effect of the operation.Result:Part I:Among 248 patients,the intercristal line was distributed in L3-L4 interspinous space in 27 cases(10.9%),male/female(18/9);L4-L5 interspinous space in 160 cases(64.5%),male/female(78/82cases);L5-S1 interspinous space in 61 cases(24.6%),male/female(22/39 cases).The upper line of posterior superior iliac spine was distributed in the L5-S1 interspinous space in 218 cases(87.9%),male/female(106/112 cases);S1-S2 interspinous space in 29 cases(11.7%),male/female(12/18 cases).The consistency between the position of upper line of posterior superior iliac spine and the L5-S1interspinous space was higher than that between the intercristal line and L4-L5 interspinous space(87.9%vs 64.5%),with significant statistical difference(X~2=37.048,P<0.05).There was significant difference between the location of intercristal line and gender(X~2=7.274,P<0.05).As the growth of the age,the location of the intercristal line tends to shift to the head side(X~2=16.185,P<0.05).There was no significant difference between the location of upper line of posterior superior iliac spine and gender(X~2=0.786,P>0.05).As the growth of the age,the location of the upper line of posterior superior iliac spine tends to shift to the head side(X~2=7.336,P<0.05).Part II:All patients underwent single segment MIS-TLIF,and there was no significant difference in preoperative general data between the two groups(all P>0.05).The first localization accuracy of the experimental group(79.1%)was higher than that of the control group(56.1%),and the difference was statistically significant(X~2=5.078,P<0.05).The preoperative location time of the experimental group(164.81±14.35s)was significantly lower than that of the control group(182.29±20.62s),and the difference was statistically significant(t=-4.489,P<0.05).The number of preoperative fluoroscopy in the experimental group was 2(2,3)times and that in the control group was 3(2,3).The number of preoperative fluoroscopy in the experimental group was significantly lower than that in the control group(Z=-3.294,P<0.05).There was no significant difference in the incision length between the experimental group(6.49±0.66cm)and the control group(6.67±0.58cm)(t=-1.356,P=0.179).There was no significant difference in VAS and ODI score between the two groups before and 3 days after operation(all P>0.05).The VAS and ODI score of the two groups 3 days after operation were statistically significant compared with those before operation(all P<0.05).Conclusion:The consistency of the position of the upper line of posterior superior iliac spine and the L5-S1interspinous space is higher than that of the intercristal line and the L4-L5 interspinous space.The accuracy of using the upper line of posterior superior iliac spine in clinical application is higher than that of the traditional intercristal line.The use of upper line of posterior superior iliac spine for preoperative segmental location of lumbar spine can shorten the preoperative location time and reduce the X-ray radiation exposure of patients and doctors.This method is a practical and reliable method for preoperative localization.The upper line of posterior superior iliac spine has a certain clinical application value as a new localization mark of lumbar vertebrae.