title: Posterior lumbar interbody fusion with instrumented posterolateral fusion in adult spondylolisthesis: description and association of clinico-surgical variables with prognosis in a series of 36 cases.
abstract: BACKGROUND
  We present our experience in the treatment of patients with isthmic or degenerative spondylolisthesis, by means of a posterior lumbar interbody fusion (PLIF) and instrumented posterolateral fusion (IPLF), and we compare them with those published in the literature. We analyse whether there exists any statistical association between the clinical characteristics of the patient, radiological characteristics of the disease and our surgical technique, with the complications and the clinical-radiological prognosis of the cases.
  
  
  METHODS
  We designed a prospective study. A total of 36 cases were operated. The patients included were 14 men and 22 women, with an average age of 57.17±27.32 years. Our technique consists of PLIF+IPLF, using local bone for the fusion. The clinical results were evaluated with the Visual Analogical Scale (VAS) and the Kirkaldy-Willis criteria. The radiological evaluation followed the Bratingan (PLIF) and Lenke (IPLF) methodology. A total of 42 variables were statistically analysed by means of SPSS18. We used the Paired Student's T-test, logistic regression and Pearson's Chi-square-test.
  
  
  RESULTS
  The spondylolisthesis was isthmic in 15 cases and degenerative in 21 cases. The postoperative evaluations had excellent or good results in 94.5% (n = 34), with a statistically significant improvement in the back pain and sciatica (p < 0.01). The rate of circumferential fusion reached was approximately 92%. We had 13.88% of transitory morbility and 0% of mortality associated with our technique. A greater age, degree of listhesis or length of illness before the intervention, weakly correlated with worse clinical results (p< -0.2). In our series, the logistical regression showed that the clinical characteristics of the patient, radiological characteristics of the lesion and our surgical technique were not associated with greater postoperative complications.
  
  
  CONCLUSIONS
  Although a higher level of training is necessary, we believe that the described technique is a very effective decision in cases of spondylolisthesis, isthmic or degenerative, refractory to conservative treatment, for the obtaining the best clinical results and rates of fusion, with similar risks to those of the other published techniques. Our statistical analysis could contribute to improve outcomes after surgery.
authors.affiliation: Department of Neurosurgery, Son Espases University Hospital, Mallorca, Spain.
authors.forename: Monica
authors.initials: M
authors.lastname: Lara-Almunia
authors.affiliation: Department of Neurosurgery, University Hospital of Salamanca, Salamanca, Spain.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Gomez-Moreta
authors.affiliation: Department of Neurosurgery, University Hospital of Salamanca, Salamanca, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Hernandez-Vicente
keywords: Spondylolisthesis; cages; instrumented posterolateral fusion; posterior lumbar interbody fusion; spinal fusion