Anatomic And Imaging Measurement Of Paraspinal Intermuscular Space On Approach For Posterior Lumbar Surgery

Objective 1.To observe the anatomic features of the paraspinal intermuscular(Wiltse)space,in order to provide the morphological data for the Wiltse approach in the posterior lumbar surgery.2.To observe and measure the distances from the inlets of Wiltse space to posterior median line of each intervertebral disc on CT and MRI pictures,and to analyze the factors(posion)influencing the location of inlets.3.To compare operative time,bleeding volume and postoperative pain score after operation between the group aided by CT and MRI and the group without CT and MRI,and evaluate the effect of CT and MRI in aiding posterior lumbar surgery along paraspinal intermuscular(Wiltse)space approach.Method 1.Ten adult cadavers were dissected on the right to observe the Wiltse space and adjacent elements,and the surgical simulation along paraspinal approach Wiltse approach was taken on the left to survey the structures and anatomic features of the paraspinal approach Wiltse approach.2.CT and MRI measurement Two hundred patients from November 2015 through January 2017 taken lumbar examination in Xintai People’s Hospital were divided into A and B groups randomly,100 in each group.All patients were taken lumbar plain scans,group A in supine position,and group B in prone position,50 from each group were scanned by CT,the rest were scanned by MRI.The images of paravertebral Wiltse space from each side of each lumbar vertebrae were observed and the distances from the inlets of Wiltse space to posterior median line were measured.3.Pedicle screw fixation along paraspinal Wiltse approach assisted by CT and MRI and its curative effect Thirty patients,from January 2016 through June 2016 in Xintai People’s Hospital for treating lumbar vertebrae compression fractures with pedicle screw fixation in the posterior lumbar vertebra paravertebral space,were divided into groups A and B,15 for each.The pedicle screw fixation for all patients was performed under fluoroscopy,the skin incision in group A was selected according to the surgeon’s experience,while in group B located by MR imaging,and the angle and depth of screw going through bilateral Wiltse approach matching exactly to the data measured from CT pictures.The intraoperative blood loss,postoperative drainage,the time of operation and hospitalization were recorded,and VAS scores were marked to evaluate the patients’ pain before and 72 hours after operation.Results 1.The Wiltse space is a space lying between the multifidus and longissimus,covered by aponeurosis of longissimus,filled with a few of adipose and connective tissue.In upper lumbar vertebrae(L1,L2),the distance from Wiltse space to the posterior median line was shorter than that in the lower lumbar vertebrae.From L1 to L5,the distances on the right were 1.67±0.21,2.17±0.32,2.61±0.24,3.11±0.24 and 3.39±0.42 cm,those on the left were 1.62±0.31,1.98±0.42,2.54±0.35,3.09±0.45 and 3.43±0.4cm.In the Wiltse space the articular process,transverse process and intervertebral foramen of lumbar vertebrae could be exposed.2.The Wiltse space can be displayed on 820 from 1000 CT pictures counting 82%,and on 945 from 1000 MRI pictures being 94.5%,thus the MRI displayed more the Wiltse space than CT did with statistical significance(P <0.05).The distances from Wiltse space to the posterior median line in prone position were slightly larger than those in prone position,and those in right resembled those in left,and statistical analysis showed no statistical significance among distances positions and sides(p> 0.05).The distances measured from L1 to L3 for male were larger than those for female with statistically significant difference(p<0.05),but those from L4 to L5.3.The operation time,the blood loss,hospitalization time and the VAS score in group A were 2.20±0.14 hours,348±13.93 ml,330±16.93 ml,2.60±0.82,16.8 ± 2.31 days,while those in group B were 1.59±0.13 hours,242±15.54 ml,233±12.51 ml,1.91±0.79,15.6±1.54 days.Statistical analysis indicated that the operation time,blood loss,drainage volume and VAS score in group B decreased significantly than did in group A with statisticaldifference(p<0.05),but the hospitalization time in group B shorted than that did in group A with no statistical significance(p> 0.05).Conclusion 1.The Wiltse space was a natural clearance in the deep paravertebral muscules,covered by the aponeurosis of longissimus.Through the space,the articular process,pedicle of vertebral arch and foramen intervertebrale could be well exposed.Awaring the Wiltse space and its’ adjacent structures is favor to surgeon operating along the paraspinal approach.2.The Wiltes space can clearly showed by MRI,and the data obtained by MRI in supine position can reflect real anatomical information on operating location and provide a valuable reference for locating the incision during a Wiltse paraspinal approach surgery.3.MRI combined with MSCT can accurately locate the incision during the pedicle screw fixation along posterior lumbar intervertebral space approach,and ensure the nailing channel,thus lessening operating injury and improving success rate of operation.