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Study DesignRetrospective cohort study.PurposeThis study aimed to investigate relationships between clinical outcomes and radiographic parameters in patients with pseudoarthrosis after posterior lumbar interbody fusion (PLIF).Overview of LiteratureIn some patients with pseudoarthrosis after PLIF, clinical symptoms improve following surgery, although pseudoarthrosis can often be one of the complications. However, there are no previous reports describing differences between patients with pseudoarthrosis after PLIF who have obtained better clinical outcomes and those who have not.MethodsTwenty-seven patients who were diagnosed with pseudoarthrosis after single-level PLIF with cortical bone trajectory screw fixation (CBT-PLIF) were enrolled in this study. They were divided into two groups based on mean improvement of 22 points on the Oswestry Disability Index (ODI) at the 2-year follow-up. Group G consisted of 15 patients who showed improvement on the ODI of ≥22 points, and group P consisted of the residual 12 patients. Radiographic parameters, percentage of slip, lumbar lordosis (LL), segmental lordosis, segmental range of motion, screw loosening, and subsidence were compared between the two groups.ResultsThere were no significant differences between the two groups on radiographic parameters except for postoperative changes in LL. Although surgery-induced changes in LL showed no significant difference between the two groups, changes in LL from before surgery to 2-year follow-up and during postoperative 2-year follow-up were significantly better in group G (mean change of LL: +3.5° and +5.1°, respectively) compared to group P (mean change of LL: −4.6° and −0.5°, respectively) (pConclusionsPatients with greater improvement in ODI gained LL over the 2-year follow-up, whereas patients with less improvement in ODI lost LL during the 2-year follow-up. These results indicate that there is a significant correlation between clinical outcomes and LL even in patients with pseudoarthrosis after single-level CBT-PLIF.
ABSTRACT
Study DesignRetrospective cohort study.PurposeThis study aimed to investigate relationships between clinical outcomes and radiographic parameters in patients with pseudoarthrosis after posterior lumbar interbody fusion (PLIF).Overview of LiteratureIn some patients with pseudoarthrosis after PLIF, clinical symptoms improve following surgery, although pseudoarthrosis can often be one of the complications. However, there are no previous reports describing differences between patients with pseudoarthrosis after PLIF who have obtained better clinical outcomes and those who have not.MethodsTwenty-seven patients who were diagnosed with pseudoarthrosis after single-level PLIF with cortical bone trajectory screw fixation (CBT-PLIF) were enrolled in this study. They were divided into two groups based on mean improvement of 22 points on the Oswestry Disability Index (ODI) at the 2-year follow-up. Group G consisted of 15 patients who showed improvement on the ODI of ≥22 points, and group P consisted of the residual 12 patients. Radiographic parameters, percentage of slip, lumbar lordosis (LL), segmental lordosis, segmental range of motion, screw loosening, and subsidence were compared between the two groups.ResultsThere were no significant differences between the two groups on radiographic parameters except for postoperative changes in LL. Although surgery-induced changes in LL showed no significant difference between the two groups, changes in LL from before surgery to 2-year follow-up and during postoperative 2-year follow-up were significantly better in group G (mean change of LL: +3.5° and +5.1°, respectively) compared to group P (mean change of LL: −4.6° and −0.5°, respectively) (pConclusionsPatients with greater improvement in ODI gained LL over the 2-year follow-up, whereas patients with less improvement in ODI lost LL during the 2-year follow-up. These results indicate that there is a significant correlation between clinical outcomes and LL even in patients with pseudoarthrosis after single-level CBT-PLIF.
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STUDY DESIGN: Retrospective cohort study. PURPOSE: We recently reported that when compared to posterior lumbar interbody fusion (PLIF) using traditional pedicle screw fixation, PLIF with cortical bone trajectory screw fixation (CBT-PLIF) provided favorable clinical outcomes and reduced the incidence of symptomatic adjacent segment pathology, but resulted in relatively lower fusion rates. Since titanium-coated polyetheretherketone (PEEK) cages (TP) could improve and accelerate fusion status after CBT-PLIF, early fusion status was compared between CBT-PLIF using TP and carbon PEEK cages (CP). OVERVIEW OF LITERATURE: A systematic review demonstrated that clinical studies at this early stage show similar fusion rates for TP compared to PEEK cages. METHODS: We studied 36 consecutive patients undergoing CBT-PLIF with TP (TP group) and 92 undergoing CBT-PLIF with CP (CP group). On multiplanar reconstruction computed tomography (MPR-CT) at 6 months postoperatively, vertebral endplate cysts (cyst signs) were evaluated and classified as diffuse or local cysts. Early fusion status was assessed by dynamic plain radiographs and MPR-CT at 1 year postoperatively. RESULTS: The incidences of cyst signs, diffuse cysts, and early fusion rate in the TP and CP groups were 38.9% and 66.3% (p0.05), respectively. Combining the two groups, 22 of 36 patients with diffuse cysts had nonunion at 1-year follow-up, compared to only three of 92 patients with local cysts or without cyst signs (p<0.01). CONCLUSIONS: Despite having fewer patients with endplate cysts at 6 months (a known risk factor for nonunion), the TP group had the same fusion rate as the CP group at 1-year follow-up. Thus, TP did not accelerate the fusion process after CBT-PLIF.
Subject(s)
Humans , Carbon , Cohort Studies , Follow-Up Studies , Incidence , Pathology , Pedicle Screws , Retrospective Studies , Risk FactorsABSTRACT
STUDY DESIGN: Clinical case series. PURPOSE: In the posterior lumbar interbody fusion (PLIF) procedure in our institute, the cephalad screw trajectory follows a mediolateral and caudocephalad directed path according to the original cortical bone trajectory (CBT) method. However, the starting point of the caudal screw is at the medial border of the pedicle on an articular surface of the superior articular process, and the trajectory takes a mediolateral path parallel to the cephalad endplate. The incidence of caudal screw loosening after PLIF with this modified CBT screw method was investigated, and significant risk factors for caudal screw loosening were evaluated. OVERVIEW OF LITERATURE: A biomechanical study of this modified caudal screw trajectory using the finite element method reported about a 20% increase in uniaxial yield pullout load compared with the traditional trajectory. However, there has been no clinical study concerning the fixation strength of this modified caudal screw trajectory. METHODS: The subjects were 193 consecutive patients who underwent single-level PLIF with modified CBT screw fixation. Caudal screw loosening was checked in computed tomography at 6 months after surgery, and screw loosening was defined as a radiolucency of 1 mm or more at the bone-screw interface. RESULTS: The incidence of caudal screw loosening after lumbosacral PLIF (46.2%) was significantly higher than that after floating PLIF (6.0%). No significant differences in sex, brand of the instruments, and diameter and length of the caudal screw were evident between patients with and without caudal screw loosening. Patients with caudal screw loosening were significantly older at the time of surgery than patients without caudal screw loosening. CONCLUSIONS: Fixation strength of the caudal screw after floating PLIF with this modified CBT screw technique was sufficiently acceptable. Fixation strength after the lumbosacral procedure was not.
Subject(s)
Humans , Clinical Study , Incidence , Methods , Pedicle Screws , Risk FactorsABSTRACT
STUDY DESIGN: Prospective cohort study. PURPOSE: To identify differences in time-dependent perioperative changes between the Japanese Orthopaedic Association (JOA) score and the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) score in patients with cervical spondylotic myelopathy (CSM) and posterior longitudinal ligament (OPLL) who underwent cervical laminoplasty. OVERVIEW OF LITERATURE: The JOA score does not take into consideration patient satisfaction or quality of life. Accordingly, the JOACMEQ was designed in 2007 as a patient-centered assessment tool. METHODS: We studied 21 patients who underwent cervical laminoplasty. We objectively evaluated the time-dependent changes in JOACMEQ scores and JOA scores for all patients before surgery and at 2 weeks, 3 months, 6 months, and 1 year after surgery. RESULTS: The average total JOA score and the recovery rate improved significantly after surgery in both groups, with a slightly better recovery rate in the OPLL group. Cervical spine function improved significantly in the CSM group but not in the OPLL group. Upper- and lower-extremity functions were more stable in the CSM group than in the OPLL group. The effectiveness rate of the JOACMEQ for measuring quality of life was quite low in both groups. In both groups, the Spearman contingency coefficients were dispersed widely except for upper- and lower-extremity function. CONCLUSIONS: Scores for upper- and lower-extremity function on the JOACMEQ correlated well with JOA scores. Because the JOACMEQ can also assess cervical spine function and quality of life, factors that cannot be assessed by the JOA score alone, the JOACMEQ is a more comprehensive evaluation tool.