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Differences In Radiologic And Clinical Outcomes Between Ankylosing Spondylitis Patients With Or Without Pseudarthrosis For Pedicle Subtraction Osteotomy

Posted on:2018-07-02Degree:MasterType:Thesis
Country:ChinaCandidate:X K ChengFull Text:PDF
GTID:2334330542968888Subject:Clinical medicine
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Objectives To compare the differences in radiologic and clinical outcomes between ankylosing spondylitis(AS)patients with or without pseudarthrosis for pedicle subtraction osteotomy(PSO).To evaluate the effectiveness and safety of PSO with posterior fusion crossing pseudarthrosis in correcting thoracolumbar kyphosis secondary to AS,and to investigate the spontaneous bone healing in pseudarthrosis.Summary of Background Data Pseudarthrosis appears as a nonunion occurring transversely through intervertebral disc and/or vertebral body in AS.PSO through pseudarthrosis has been confirmed to be effective and safe to correct thoracolumbar kyphosis for these patients.While,others suggested a supplemental anterior bone grafting after PSO through pseudarthrosis promoting the bone healing of pseudarthrosis.However,osteotomy at the pseudarthrosis level is technically demanding and challenging,and a second-stage anterior fusion may increase the risk of surgical complications related to anterior procedure.To date,few studies focused on the appropriate surgical options for AS patients with pseudarthrosis but not associated with neurological deficits.Methods Twelve AS patients(10 males/2 females)with pseudarthrosis underwent PSO below/above the pseudarthrosis with posterior fusion(group P)and 35 AS patients(32 males/3 females)without pseudarthrosis underwent PSO(group NP)were included in the study.The Oswestry Disability Index(ODI)scores and visual analogue scale(VAS)were used to assess life quality.The sagittal spinal-pelvic parameters including global kyphosis(GK),Cobb angle of pseudarthrosis levels(CPL),thoracic kyphosis(TK),lumbar lordosis(LL),pelvic incidence(PI),pelvic tilt(PT),sacral slope(SS)and sagittal vertical axis(SVA)were measured and compared between the two groups.Results The mean follow-up duration was 27.5 months(range,12-48 months)in group P and 31.7 months(range,24-60 months)in group NP.All of the GK,LL,SVA,VAS and ODI scores improved significantly in group P(p<0.05).The mean correction of GK was 53.0°(from 75.5°± 16.1°before surgery to 22.5°± 13.1° after surgery,p<0.05).GK changed to 24.3° ± 13.3° at the final follow-up with the mean loss of correction of 1.8°.There was a significant difference between the preoperative(-6.4° ± 19.1°)and postoperative(40.70° ± 14.1°)LL(p<0.05).At the final follow-up,it changed to 40.8°±12.6° with a mean loss of correction of 0.1°.The mean SVA improved from 175.8 mm before surgery to 58.2 mm after surgery(p<0.05)with an average correction of 117.6 mm and changed to 50.3 mm at the final follow-up.The CPL was-5.3°±12.8°after surgery and-4.9° ± 14.3°at the final follow-up,with the loss of CPL of 0.3° ± 5.3° in group P.The mean VAS and ODI scores significantly improved from 5.1 and 36.6 before surgery to 1.1 and 9.5 at the final follow-up in group P,and significantly improved from 5.2 and 34.5 to 1.6 and 14.0 in group NP.No significant difference was noted between the two groups(p>0.05)in GK,LL,SVA,VAS and ODI scores.Solid radiological fusion was observed in the segment of pseudarthrosis in 27.5 months on average.At the final follow-up,there was no persistent lucent line at the pseudarthrosis or the osteotomy site.Continuous trabecular bone can be observed crossing the level of the pseudarthrosis and the osteotomy site.ConclusionsFor AS patients with pseudarthrosis not complicating with neurological deficits,PSO below/above the pseudarthrosis with only posterior instrumentation is a method effective for spontaneous bone healing,if the instrumentation crosses the pseudarthrosis.This important finding implies that anterior debridement of pseudarthrosis and supplemental fusion are not indispensable for these patients before or after PSO surgical correction for kyphosis.
Keywords/Search Tags:Ankylosing spondylitis, Kyphosis, Pseudarthrosis, Pedicle subtraction osteotomy, Posterior fusion
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