Minimally invasive transforaminal lumbar interbody fusion with unilateral pedicle screw fixation (UNILF): outcomes at 7 years.

PURPOSE: To assess clinical, functional and radiographical results of one-level minimally invasive transforaminal interbody fusion with unilateral pedicle screw fixation (UNILIF) in the treatment of stable lumbar degenerative diseases with a minimum of 5 years of follow-up. MATERIAL AND METHOD: From January 2012 to December 2016, clinical and radiological data of patients with degenerative lumbar disease managed by UNILIF were prospectively collected. Patients with a follow-up that ended before 5 years were excluded. SF-12, Oswestry disability index (ODI) and visual analog scale (VAS) were collected preoperatively, at 2 years and at the last follow-up. A full-spine standing radiograph was performed at each follow-up appointment. RESULTS: Mean operative time was 74.7 (± 19) minutes, mean blood loss was 131.1 (± 207) ml and mean follow-up was 7.5 (± 1.7) years. All functional scores and VAS were significantly improved between the preoperative and the 2 years postoperative. Between the 2 years postoperative and the last follow-up ODI and VAS continued to significantly improved. Fusion rate was 98.6% on radiographic analysis at follow-up. CONCLUSION: UNILIF method is a safe and effective surgical strategy. It provides a durable improvement in functional score over 7 years of follow-up with a stable radiological correction over time.

Intraoperative neurophysiological monitoring in scoliosis surgery: literature review of the last 10 years.

INTRODUCTION: Patients with spinal deformities undergoing corrective surgery are at risk for iatrogenic spinal cord injury (SCI) and subsequent neurological deficit. Intraoperative neurophysiological monitoring (IONM) allows early detection of SCI which enables early intervention resulting in a better prognosis. The primary aim of this literature review was to search if there are threshold values of TcMEP and SSEP in the literature that are widely accepted as alert during IONM. The secondary aim was to update knowledge concerning IONM during scoliosis surgery. METHOD: PubMed/MEDLINE and Cochrane library electronic databases were used to search publication from 2012 to 2022. The following keywords were used: evoked potential, scoliosis, surgery, intraoperative monitoring and neurophysiological. We included all studies dealing with SSEP and TcMEP monitoring during scoliosis surgery. Two authors reviewed all titles and abstracts to identify studies that met the inclusion criteria. RESULTS: We included 43 papers. Rates of IONM alert and neurological deficit varied from 0.56 to 64% and from 0.15 to 8.3%, respectively. Threshold values varied from a loss of 50 to 90% for TcMEP amplitude, whereas it seems that a loss of 50% in amplitude and/or an increase of 10% of latency is widely accepted for SSEP. Causes of IONM changes most frequently reported were surgical maneuver. CONCLUSION: Concerning SSEP, a loss of 50% in amplitude and/or an increase of 10% of latency is widely accepted as an alert. For TcMEP, it seems that the use of highest threshold values can avoid unnecessary surgical procedure for the patient without increasing risk of neurological deficit.

Clinical predictive model of lumbar curve Cobb angle below selective fusion for thoracic adolescent idiopathic scoliosis: a longitudinal multicenter descriptive study.

PURPOSE: To implement a clinically applicable, predictive model for the lumbar Cobb angle below a selective thoracic fusion in adolescent idiopathic scoliosis. METHODS: A series of 146 adolescents with Lenke 1 or 2 idiopathic scoliosis, surgically treated with posterior selective fusion, and minimum follow-up of 5 years (average 7) was analyzed. The cohort was divided in 2 groups: if lumbar Cobb angle at last follow-up was, respectively, ≥ or < 10°. A logistic regression-based prediction model (PredictMed) was implemented to identify variables associated with the group ≥ 10°. The guidelines of the TRIPOD statement were followed. RESULTS: Mean Cobb angle of thoracic main curve was 56° preoperatively and 25° at last follow-up. Mean lumbar Cobb angle was 33° (20; 59) preoperatively and 11° (0; 35) at last follow-up. 53 patients were in group ≥ 10°. The 2 groups had similar demographics, flexibility of both main and lumbar curves, and magnitude of the preoperative main curve, p > 0.1. From univariate analysis, mean magnitude of preoperative lumbar curves (35° vs. 30°), mean correction of main curve (65% vs. 58%), mean ratio of main curve/distal curve (1.9 vs. 1.6) and distribution of lumbar modifiers were statistically different between groups (p < 0.05). PredictMed identified the following variables significantly associated with the group ≥ 10°: main curve % correction at last follow-up (p = 0.01) and distal curve angle (p = 0.04) with a prediction accuracy of 71%. CONCLUSION: The main modifiable factor influencing uninstrumented lumbar curve was the correction of main curve. The clinical model PredictMed showed an accuracy of 71% in prediction of lumbar Cobb angle ≥ 10° at last follow-up. LEVEL OF EVIDENCE IV: Longitudinal comparative study.

Fusion and clinical outcomes of lumbar interbody fusion for low-grade isthmic spondylolisthesis.

INTRODUCTION: Low-grade isthmic spondylolisthesis (ISPL) is generally treated by circumferential fusion with interbody graft, although there is no consensus on technique. HYPOTHESIS: The various interbody fusion strategies provide satisfactory fusion rates and clinical results. METHODS: A multicenter retrospective study analyzed lumbar interbody fusion for low-grade ISPL performed between March 2016 and March 2019. Techniques comprised: circumferential fusion on a posterior or a transforaminal approach (PLIF, TLIF: n=57), combined anterior (ALIF)+posterolateral fusion (ALIF+PLF: n=60), and ALIF+percutaneous posterior fixation (ALIF+PPF: n=55). Function was assessed on a lumbar and a radicular visual analog scale (AVS-L, VAS-R), Oswestry Disability Index (ODI) and Short Form 12 (SF12). RESULTS: Among the 129 patients, 85.3% showed fusion (Lenke 1 or 2), with no significant differences between the ALIF-PLF or ALIF-PPF groups and the PLIF or TLIF groups (p=0.3). Likewise, there was no difference in fusion rates between the ALIF-PPF and ALIF-PLF subgroups (p=0.28). VAS-L (p<0.001) and VAS-R (p<0.0001), ODI (p<0.001) and SF12 physical (PCS) (p<0.01) and mental component sores (MCS) (p<0.001) all showed significant improvement at 12months. Combined approaches provided greater clinical efficacy than TLIF or PLIF for lumbar (p<0.0001) and radicular pain (p<0.05), ODI (p<0.0001) and SF12 PCS (p<0.01). At 12months, there was no clinical difference between the ALIF-PPF and ALIF-PLF subgroups. However, patents with interbody non-union (Lenke 3 or 4) had lower SF12 PCS scores (p<0.004) and VAS-L ratings (p<0.001) than Lenke 1-2 patients. CONCLUSION: Low-grade ISPL treated by circumferential arthrodesis and interbody graft showed 85.3% consolidation at 2years, with equivalent outcomes between anterior and posterior techniques. Successful fusion was associated with better clinical results. LEVEL OF EVIDENCE: IV.

Surgical management of isthmic spondylolisthesis: A comparative study of postoperative outcomes between ALIF and TLIF.

INTRODUCTION: Circumferential fusion by the anterior (ALIF) or transforaminal (TLIF) approach combined with posterior instrumentation is currently used for the surgical treatment of low-grade isthmic spondylolisthesis. But few studies have compared the clinical and radiological outcomes of various interbody fusion techniques. The objective of this study was to compare the clinical and radiological results at 2 years postoperative of two fusion techniques-TLIF versus ALIF plus posterior instrumentation-for low-grade isthmic spondylolisthesis in adults. MATERIALS AND METHODS: This was an observational multicenter study done at nine French healthcare facilities specialized in spine surgery. The inclusion criteria were minimum age of 18 years, grade 1-3 isthmic spondylolisthesis, ALIF+posterior fixation (ALIF+PS) or TLIF, minimum follow-up of 2 years. Clinical and radiological evaluations were done preoperatively and at 2 years of follow-up. A lumbar CT scan was done at 1 year postoperative to evaluate fusion. RESULTS: The cohort consisted of 89 patients (50 women, 39 men) with a mean age of 47.7±12.3 (18-79) years. The patients in the ALIF groups (n=71) had a significantly longer hospital stay than those in the TLIF group (n=18): 5.7 days versus 4.6 days (p=.04). However, their medical leave from work was significantly shorter: 31.0 weeks versus 40.7 (p=.003). Lumbar pain VAS diminished faster in the ALIF groups, with a significantly larger drop than the TLIF group in the first 3 months postoperative. Only the increase in lumbar disc lordosis was larger in the ALIF group: 11.7°±12.0° versus 6.0°±11.7° (p=.036). There was a significant correlation between the increase in global lordosis and reduction in lumbar VAS at 2 years postoperative (ρ=-0.3295; p=.021). CONCLUSION: ALIF+PS provides a faster relief of postoperative low back pain than TLIF but there are no significant clinical differences between techniques at 2 years of follow-up. Despite better restoration of disc lordosis in the ALIF+PS group, there was no difference in the restoration of global lordosis. LEVEL OF EVIDENCE: III; multicenter comparative study.

Minimally invasive unilateral lumbar interbody fusion (UNILIF) in over-80-year-olds. Continuous series of 42 patients at 1.4 years' follow-up.

INTRODUCTION: In lumbar stenosis, surgery aims to improve quality of life in increasingly elderly patients. Minimally invasive techniques better suit the requirements of elderly patients with increasing functional demand. HYPOTHESIS: The UNILIF unilateral lumbar interbody fusion technique improves functional scores at 1 year in over-80 year-olds, with low morbidity. METHOD: Patients undergoing minimally invasive decompression with transforaminal lumbar interbody fusion (TLIF) associated to unilateral pedicle screwing for degenerative lumbar stenosis were analyzed at a minimum 1 year's follow-up. SF12, Oswestry Disability Index (ODI) and Quebec scores and sagittal spinopelvic radiographic parameters were assessed at follow-up. Surgical and general complications were also collated. RESULTS: In all, 42 patients (64.3% female; mean age, 83.7±2.9 years) were treated by UNILIF at levels L2-L3 (3.8%), L3-L4 (15.4%), L4-L5 (71.2%) and L5-S1 (9.6%). Mean follow-up was 520±226 days (range, 340-1166 days). Mean preoperative SF12 score was 77.5±10.9, with significant improvement at last follow-up: 81.9±138 (p<0.05). Mean preoperative ODI was 44.4%±14.0, with significant improvement at last follow-up: 32.4%±13.3 (p<0.001). Mean preoperative Quebec score was 42.9±19.9, with significant improvement at last follow-up: 28.5±21.9 (p<0.001). Spinopelvic sagittal balance was not affected by the UNILIF procedure. There were no cases of infection or severe general complications during follow-up, although 2 cases of non-union required revision surgery. CONCLUSION: Lumbar stenosis surgery by UNILIF improved functional scores at 1 year, with low morbidity. It is a suitable strategy for degenerative lumbar stenosis in elderly patients. LEVEL OF EVIDENCE: IV, non-comparative cohort study.