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Study Design Randomized controlled trial. Objective Despite a large number of publications of outcomes after spinal fusion surgery, there is still no consensus on the efficacy of the several different fusion methods. The aim of this study was to determine whether transforaminal lumbar interbody fusion (TLIF) results in an improved clinical outcome compared with uninstrumented posterolateral fusion (PLF) in the surgical treatment for chronic low back pain. Methods This study included 135 patients with degenerative disk disease ( n = 96) or postdiskectomy syndrome ( n = 39). Inclusion criteria were at least 1 year of back pain with or without leg pain in patients aged 20 to 65 with one- or two-level disease. Exclusion criteria were sequestration of disk hernia, psychosocial instability, isthmic spondylolisthesis, drug abuse, and previous spine surgery other than diskectomy. Pain was assessed by visual analog scale (pain index). Functional disability was quantified by the disability rating index and Oswestry Disability Index. The global outcome was assessed by the patient and classified as much better, better, unchanged, or worse. The patients were randomized to conventional uninstrumented PLF ( n = 67) or TLIF ( n = 68). PLF was performed in a standardized fashion using autograft. TLIF was performed with pedicle titanium screw fixation and a porous tantalum interbody spacer with interbody and posterolateral autograft. The clinical outcome measurements were obtained preoperatively and at 12 and 24 months postoperatively. The 2-year follow-up rate was 98%. Results The two treatment groups improved significantly from preoperatively to 2 years’ follow-up. At final follow-up, the results in the TLIF group were significantly superior to those in the PLF group in pain index (2.0 versus 3.9, p = 0.007) and in disability rating index (22 versus 36, p = 0.003). The Oswestry Disability Index was better in the TLIF group (20 versus 28, p = 0.110, not significant). The global assessment was clearly superior in the TLIF group: 63% of patients scored “much better” in the TLIF group as compared with 48% in the PLF group ( p = 0.017). Conclusions The results of the current study support the use of TLIF rather than uninstrumented PLF in the surgical treatment of the degenerative lumbar spine. The less optimal outcome after uninstrumented PLF may be explained by the much higher reoperation rate.

Introduction One of the most deleterious complications after pedicle subtraction osteotomy (PSO) is proximal junctional failure (PJF), typically leading to reoperations with unpredictable outcome. Various measures to prevent it have been suggested, all, however, with limited success. The purpose of this study was to correlate the occurrence of PJF to preoperative clinical as well as postoperative radiological factors, to define preventive strategies. Patients and Methods This retrospective study included 104 consecutive patients with a kyphotic deformity and sagittal imbalance operated with a PSO. There were 35 men and 71 women, mean age 58 (range, 18–80 years). There were 28 patients with flat back syndrome after lumbar fusion (FBS-LF), 21 degenerative scoliosis (DS), 20 posttraumatic kyphosis (PTK), 16 flat back syndrome after scoliosis surgery (FBS-SF), 9 adult idiopathic scoliosis (AISA), 6 neuromuscular scoliosis (NS), 3 congenital scoliosis (CS), and 1 ankylosing spondylitis (AS). A total of 83 (80%) patients were fused to the thoracolumbar or thoracic level and 21 (19%) patients were fused to the upper thoracic spine. The patients were followed up 12 to 36 months postoperatively with radiographs and reoperations documented for PJF. Results There were 18 patients with PJF requiring revision surgery (17%). In 10 patients PJF occurred before 6 months, in 4 between 6 and 12 months, and in 4 after 12 months. Mean time to PJF was 9 months. There were 16 PJFs of the bony type (fracture) and 2 of the ligamentous type. Mean age among those with PJF was 66 years as compared with 55 years in non-PJF. Female proportion was 77% in PJF and 66% in non-PJF. Patients fused to the thoracolumbar junction had a PJF in 28% of cases compared with 10% of patients with a high thoracic fusion ( p 15 degrees, and also in patients with a mismatch of pelvic incidence and sacral slope. The average local correction by the PSO was 31 degrees. There was no correlation between the magnitude of correction and the occurrence of a PJF. Conclusions A PJF is a common complication to a PSO. We identified the following risk factors; previous lumbar fusion, preoperative osteoporotic fracture, a PI-LL mismatch of > 15 degrees and upper instrumented vertebra in thoracolumbar region, with previous lumbar fusion being the most common risk factor, found in 55% of patients with a PJF. The results of the study add to the difficult selection of patients suitable for a PSO for correction of sagittal imbalance.