Anatomy And Preliminary Clinical Research Of The Paraspinal Approach For Treatment Of Thoracolumbar Fractures-dislocation By One-stage Decompression And Reconstruction

Objetives:(1) To study the local anatomical structure of paraspinal approach tothe thoracolumbar in adult cadavers and to measure the parameters on MRI to providethe reference data for anterior and middle column reconstruction.of the thoracolumbarfracture-dislocation.(2) A preliminary evaluation of clinical outcomes was carried outby comparing the clinical data of perioperative period and the post-operativefollow-up between the paraspinal approach group (group A) and the posterior medianapproach group (group B).Materials&Methods:(1) Ten adult cadavers treated by formalin were applied in theanatomy study. The observation of the structure of paraspinal approach and themorphology of multifuds were done after exposing the musulus multifuds. Thedistances between the posterior midline and the outer edge of multifuds, and theconjunction of multifuds with vertebral plate, and the superior articular process weremeasured at each level of the thoracolumbar segment.(2) Fifty MRI withtranspedicular cross-sectional plane from the adults without spinal fracture-dislocationwere selected for measurement of the length of operative channel and the tilt angle ofoperative channel and the operative scale. The distance the skin surface of the outeredge of the multifud and the posterior edge of vertebral body was measured torepresent the operative channel. The angle between the outer edge of the spinal cordand multifud was measured to represent the operative angle. The exposing area of thevertebral body through the angle was measured to represent the operative scale.(3)Thirty-five patients who suffered from thoracolumbar fractures-dislocation andtreated by anterior and middle column reconstruction were selected from Chen ZhouFirst People’s Hospital affiliated to University of South China according to the inclusion and exclusion criteria, from January2010to March2013. Sixteen patientswere classified into the paraspinal approach group (group A) and19patients into theposterior median approach group (group B). The operative time, intraoperative bloodloss and postoperative drainage were evaluated; The anterior height of vertebral body,the area of spinal canal and the Cobb’s angle of the suffered vertebra were measuredpreoperatively and postoperatively. The ODI score were carried out preoperativelyand1month,3months,6months and12month post-operative follow-up. The VASscore were recorded preoperatively and3days,1week,1month,6monthspostoperatively and12months post-operative follow-up. The parameters above werecompared between group A and group B.Results:(1) The gap of multifuds and longissimus muscle is easily observed andseparated by connective fiber. The gap was filled with loose connective tissue withsome muscle fiber on the surface at thorcolumbar segment.There are no nerve andblood vessel at the surface of multifuds. The nerve and blood vessel was founded inthe surface of longissimus muscle. The distance between the outer edge of multifudsand the posterior midline at T11level is15.85±3.19mm, T12level is16.29±3.09mm、 L1level is19.30±3.10mm、 L2level is21.17±4.39mmrespectively; The distance that the conjunction of multifuds with vertebral plate to theposrerior midline at T11level is16.64±2.47mm,T12level is17.52±2.26mm,L1levelis19.23±2.43mm,L2level is20.39±2.26mm; The distance that the superior articularprocess to the posrerior midline at T11level is18.16±2.62mm,T12level is19.45±2.59mm,L1level is21.49±1.49mm,L2level is22.36±0.63mm.(2) The lengthof operation channel at T11level is52.81±2.28mm,T12level is56.68±2.03mm,L1level is61.31±4.18mm,L2level is65.14±1.74mm; The tilt angle of operation channelat T11level is9.79±1.45°,T12level is10.03±1.27°,L1level is10.46±1.17°，L2levelis11.01±1.08°; The area can be processed at T11level is41.24±3.66%,T12level is40.40±2.90%,L1level is41.25±2.25%,L2level is41.68±1.86%.(3) There wassignificantly differences in operative time, intraoperative blood loss, postoperativedrainage and the low back pain relief beween in group A and in group B (p<0.05);There are no significantly differences in the anterior height of vertebral body, the area of spinal canal and the Cobb’s angle of the suffered vertebra between group A andgroup B (p>0.05).Conclusions:(1) The gap of multifuds and longissimus muscle is natural. The surfaceof longissimus muscle have nerve and blood vessel distributed, it should be protectedduring operation. The surface projection point of paraspinal approach to the posteriormidline is15.85-21.17mm, it can help us to locate the position of the operationincision; The distance that the conjunction of multifuds with vertebral plate to theposterior midline is16.64-20.39mm, it can provide reference data for the width oflaminectomy. The length of operation channel is52.81-65.14mm; The tilt angle ofoperation channel is9.79°-11.01°; The operative area is40.40%-41.68%of thevertebral cross-sectinal area. These measurement illustrate that the paraspinalapproach for treatment of thoracolumbar fractures-dislocation by anterior and middlecolumn reconstruction is safe and practicable.(2) The paraspinal approach group is superior to posterior medianapproach group in operative time, intraoperative blood loss, postoperative drainageand the low back pain relief, but the effective of reduction and reconstruction is nearly.The paraspinal approach for treatment of thoracolumbar fractures-dislocation byone-stage decompression and reconstruction can be one of the selections for treatmentthoracolumbar fractures-dislocation.