Analysis of the causes of cage subsidence after oblique lateral lumbar interbody fusion / 中国骨伤

OBJECTIVE@#To observe the cage subsidence after oblique lateral interbody fusion (OLIF) for lumbar spondylosis, summarize the characteristics of the cage subsidence, analyze causes, and propose preventive measures.@*METHODS@#The data of 144 patients of lumbar spine lesions admitted to our hospital from October 2015 to December 2018 were retrospectively analyzed. There were 43 males and 101 females, and the age ranged from 20 to 81 years old, with an average of (60.90±10.06) years old. Disease types:17 patients of lumbar intervertebral disc degenerative disease, 12 patients of giant lumbar disc herniation, 5 patients of discogenic low back pain, 33 patients of lumbar spinal stenosis, 26 patients of lumbar degenerative spondylolisthesis, 28 patients of lumbar spondylolisthesis with spondylolisthesis, 11 patients of adjacent vertebral disease after lumbar internal fixation, 7 patients of primary spondylitis in the inflammatory outcome stage, and 5 patients of lumbar degenerative scoliosis. Preoperative dual-energy X-ray bone mineral density examination showed 57 patients of osteopenia or osteoporosis, and 87 patients of normal bone density. The number of fusion segments:124 patients of single-segment, 11 patients of two-segment, 8 patients of three-segment, four-segment 1 patient. There were 40 patients treated by stand-alone OLIF, and 104 patients by OLIF combined with posterior pedicle screw. Observed the occurrence of fusion cage settlement after operation, conducted monofactor analysis on possible risk factors, and observed the influence of fusion cage settlement on clinical results.@*RESULTS@#All operations were successfully completed, the median operation time was 99 min, and the median intraoperative blood loss was 106 ml. Intraoperative endplate injury occurred in 30 patients and vertebral fracture occurred in 5 patients. The mean follow-up was (14.57±7.14) months from 6 to 30 months. During the follow-up, except for the patients of primary lumbar interstitial inflammation and some patients of lumbar spondylolisthesis with spondylolisthesis, the others all had different degrees of cage subsidence. Cage subsidence classification:119 patients were normal subsidence, and 25 patients were abnormal subsidence (23 patients were gradeⅠ, and 2 patients were gradeⅡ). There was no loosening or rupture of the pedicle screw system. The height of the intervertebral space recovered from the preoperative average (9.48±1.84) mm to the postoperative average (12.65±2.03) mm, and the average (10.51±1.81) mm at the last follow-up. There were statistical differences between postoperative and preoperative, and between the last follow-up and postoperative. The interbody fusion rate was 94.4%. The low back pain VAS decreased from the preoperative average (6.55±2.2 9) to the last follow-up (1.40±0.82), and there was statistically significant different. The leg pain VAS decreased from the preoperative average (4.72±1.49) to the final follow-up (0.60±0.03), and the difference was statistically significant (t=9.13, P<0.000 1). The ODI index recovered from the preoperative average (38.50±6.98)% to the latest follow-up (11.30±3.27)%, and there was statistically significant different. The complication rate was 31.3%(45/144), and the reoperation rate was 9.72%(14/144). Among them, 8 patients were reoperated due to fusion cage subsidence or displacement, accounting for 57.14%(8/14) of reoperation. The fusion cage subsidence in this group had obvious characteristics. The monofactor analysis showed that the number of abnormal subsidence patients in the osteopenia or osteoporosis group, Stand-alone OLIF group, 2 or more segments fusion group, and endplate injury group was higher than that in the normal bone mass group, OLIF combined with pedicle screw fixation group, single segment fusion group, and no endplate injury group, and the comparison had statistical differences.@*CONCLUSION@#Cage subsidence is a common phenomenon after OLIF surgery. Preoperative osteopenia or osteoporosis, Stand-alone OLIF, 2 or more segments of fusion and intraoperative endplate injury may be important factors for postoperative fusion cage subsidence. Although there is no significant correlation between the degree of cage subsidence and clinical symptoms, there is a risk of cage migration, and prevention needs to be strengthened to reduce serious complications caused by fusion of cage subsidence, including reoperation.

Effects of posterior pedicle screw internal fixation on early Cage subsidence after oblique lateral lumbar interbody fusion / 西安交通大学学报(医学版)

【Objective】 To investigate the effects of one-stage additional posterior pedicle screws （PPS） internal fixation on early Cage subsidence after oblique lateral interbody fusion （OLIF）. 【Methods】 We made a retrospective analysis of 118 patients with lumbar degenerative diseases treated with OLIF at the Department of Orthopedics， Sir Run Run Shaw Hospital， School of Medicine， Zhejiang University， from January 2016 to December 2019. We divided the patients into OLIF stand-alone group （58 ones） and OLIF with PPS fixation group （60 ones） according to the surgical procedure. All the patients had preoperative frontal and lateral radiographs of the lumbar spine， and CT and MR scans were performed. The clinical outcomes and reoperation rates of the two groups were compared at immediate postoperative follow-up and at 1， 3， 6 and 12 months. X-ray and CT examinations were performed to assess Cage subsidence in both groups at each postoperative follow-up. 【Results】 There was no statistical difference between the two groups in baseline data and surgical segmentation. Of the 118 patients with 141 discs who underwent OLIF surgery， 58 patients with 68 discs received OLIF stand-alone surgery and 60 ones with 73 discs received OLIF with PPS fixation. There were no significant differences in intraoperative bleeding， complications， or postoperative clinical outcomes between the two groups （P>0.05）， and the Cage subsidence rate was 22.4% in OLIF stand-alone group and 5% in OLIF with PPS fixation group， with significant difference between the two groups （P<0.01）. 【Conclusion】 Both OLIF stand-alone and OLIF additional PPS fixation can achieve good early clinical outcomes， and first-stage additional PPS fixation can significantly reduce the occurrence of Cage subsidence in the early postoperative period after OLIF.

Risk Factors of Cage Subsidence after Posterior Lumbar Interbody Fusion

STUDY DESIGN: Retrospective study. OBJECTIVES: The purpose of this study was to evaluate risk factors for subsidence after posterior lumbar interbody fusion (PLIF). SUMMARY OF LITERATURE REVIEW: Body mass index (BMI), bone mineral density (BMD), cage characteristics (titanium or poly-ether-ether-ketone (PEEK)) and degree of disc distraction are risk factors for cage subsidence after PLIF. MATERIALS AND METHODS: From January 2010 to January 2015, a total of 69 patients (93 segments) who were diagnosed with degenerative lumbar spine disease at the current authors' institution and underwent follow-up for at least 1 year were included in this retrospective study. Data on all factors related to cage subsidence were taken into consideration. The degree of association for each of the factors was determined through the calculation of odds ratios (ORs) with a 95% confidence interval. Logistic regression analyses were performed. The P-value that represented statistical significance was set below 0.05. RESULTS: There were no significant associations between fused segment level and cage subsidence (p=0.588), nor were there any significant associations between the kind of cage (titanium or PEEK) and cage subsidence (p=0.371). Using logistic regression, the factors with a P-value below the 0.20 level in univariate analyses were included in the multivariate analyses. In multivariate analyses, diabetes mellitus (DM) (p=0.029, OR, 4.524), osteoporosis (p=0.026, OR, 6.046), and degree of disc distraction (p=0.010, OR, 1.446) had significant associations with cage subsidence. In addition, there were significant associations between cage subsidence and instrument failure (p=0.008, OR, 8.235). CONCLUSIONS: DM and osteoporosis, which may affect bony structures, have significant associations with cage subsidence after PLIF. Cage insertion with excessive disc distraction during surgery may also affect cage subsidence after PLIF.

Comparison According to Fusion Level in ACDF Using PEEK Cage Alone for Degenerative Cervical Disease / 대한정형외과학회잡지

PURPOSE: This study examined the clinical efficacy of an anterior cervical discectomy and fusion (ACDF) with PEEK (polyetheretherketone) cage alone with regard to the clinical and radiological outcomes, as well as the risk factors for the cage subsidence. MATERIALS AND METHODS: A total of 128 patients who underwent group A (1-level, n=48), group B (2-levels, n=57), group C (3-levels, n=23) ACDF using a PEEK cage alone were enrolled in this study. The fusion rate, segmental kyphosis were assessed by radiographs. The clinical outcomes were assessed using the Visual Analog Scale (VAS) and Neck Disability Index (NDI). The risk factors for cage subsidence were analyzed according to the difference in incidence between the subsidence group and non-subsidence group. RESULTS: Solid fusion was achieved in 93.8% (45/48), 71.9% (41/57) and 69.6% (15/23) of subjects in group A, B and C, respectively. Segmental kyphosis was observed in 22.9% (11/48), 43.9% (25/57) and 47.8% (11/23) of subjects in group A, B and C, respectively. The VAS scores changed from 7.79+/-1.01 in group A, 7.74+/-1.09 in group B, 7.91+/-0.79 in group C preoperatively to 4.23+/-1.29 in group A, 5.25+/-1.34 in group B and 5.35+/-1.07 in group C at the last follow up. In addition, the NDI was also improved at the last follow up. The VAS score and NDI at the last follow up were similar in the subsidence and non-subsidence group. The 3-level ACDF (p=0.05), osteoporosis (p=0.01), and old age (p=0.01) were the risk factors for cage subsidence. CONCLUSION: Only 1 level ACDF with PEEK cage alone was similar in clinical and radiologic (solid fusion rate, local kyphosis) outcomes compared to ACDF with published other modalities. Old age, 3 fusion level, osteoporosis, and C6-7 fusion were risk factors for the cage subsidence with higher complication rates.