scholarly journals The association between lower Hounsfield units on computed tomography and cage subsidence after lateral lumbar interbody fusion

2020 ◽  
Vol 49 (2) ◽  
pp. E8
Author(s):  
Zhuo Xi ◽  
Praveen V. Mummaneni ◽  
Minghao Wang ◽  
Huibing Ruan ◽  
Shane Burch ◽  
...  

OBJECTIVEOne vexing problem after lateral lumbar interbody fusion (LLIF) surgery is cage subsidence. Low bone mineral density (BMD) may contribute to subsidence, and BMD is correlated with Hounsfield units (HUs) on CT. The authors investigated if lower HU values correlated with subsidence after LLIF.METHODSA retrospective study of patients undergoing single-level LLIF with pedicle screw fixation for degenerative conditions at the University of California, San Francisco, by 6 spine surgeons was performed. Data on demographics, cage parameters, preoperative HUs on CT, and postoperative subsidence were collected. Thirty-six–inch standing radiographs were used to measure segmental lordosis, disc space height, and subsidence; data were collected immediately postoperatively and at 1 year. Subsidence was graded using a published grade of disc height loss: grade 0, 0%–24%; grade I, 25%–49%; grade II, 50%–74%; and grade III, 75%–100%. HU values were measured on preoperative CT from L1 to L5, and each lumbar vertebral body HU was measured 4 separate times.RESULTSAfter identifying 138 patients who underwent LLIF, 68 met the study inclusion criteria. All patients had single-level LLIF with pedicle screw fixation. The mean follow-up duration was 25.3 ± 10.4 months. There were 40 patients who had grade 0 subsidence, 15 grade I, 9 grade II, and 4 grade III. There were no significant differences in age, sex, BMI, or smoking. There were no significant differences in cage sizes, cage lordosis, and preoperative disc height. The mean segmental HU (the average HU value of the two vertebrae above and below the LLIF) was 169.5 ± 45 for grade 0, 130.3 ± 56.2 for grade I, 100.7 ± 30.2 for grade II, and 119.9 ± 52.9 for grade III (p < 0.001). After using a receiver operating characteristic curve to establish separation criteria between mild and severe subsidence, the most appropriate threshold of HU value was 135.02 between mild and severe subsidence (sensitivity 60%, specificity 92.3%). After univariate and multivariate analysis, preoperative segmental HU value was an independent risk factor for severe cage subsidence (p = 0.017, OR 15.694, 95% CI 1.621–151.961).CONCLUSIONSLower HU values on preoperative CT are associated with cage subsidence after LLIF. Measurement of preoperative HU values on CT may be useful when planning LLIF surgery.

2006 ◽  
Vol 5 (6) ◽  
pp. 534-539 ◽  
Author(s):  
Aaron R. Cutler ◽  
Saquib Siddiqui ◽  
Mohan Avinash L. ◽  
Virany H. Hillard ◽  
Franco Cerabona ◽  
...  

Object Transforaminal lumbar interbody fusion (TLIF) is an accepted alternative to circumferential fusion of the lumbar spine in the treatment of degenerative disc disease, spondylolisthesis, and recurrent disc herniation. To maintain disc height while arthrodesis takes place, the technique requires the use of an interbody spacer. Although titanium cages are used in this capacity, the two most common spacers are polyetheretherketone (PEEK) cages and femoral cortical allografts (FCAs). The authors compared the clinical and radiographic outcomes of patients who underwent TLIF with pedicle screw fixation, in whom either a PEEK cage or an FCA was placed as an interbody spacer. Methods The charts and x-ray films obtained in 39 patients (age range 33–68 years, mean 44.7 years) who underwent single-level TLIF between October 2001 and April 2004 and in whom either a PEEK cage (18 patients) or FCA (21 patients) was placed as an interbody spacer were evaluated in a retrospective study. Radiological outcome was based on fusion rate and a comparison of the initial postoperative lordotic angle on standing lateral radiographs with that at long-term follow up (mean follow up 15.1 months, minimum 12 months). To control for variations in radiographic magnification, the authors used lordotic angle as an indirect measure of disc space height. Clinical outcome was assessed using the Oswestry Disability Index (ODI). There were no major complications in either group. Radiographically documented fusion occurred in all patients in the PEEK group and 95.2% of those in the FCA group. Pseudarthrosis developed in one patient in the FCA group, and this patient underwent additional surgery. In both groups, the mean lordotic angle changed by less than 2.20° during the postoperative period, and the mean postoperative ODI score was more than 40 points lower than the mean preoperative score. There was no significant difference between the two groups in mean change in lordotic angle (p = 0.415) and mean change in ODI score (p = 0.491). Conclusions Both PEEK cages and FCAs are highly effective in promoting interbody fusion, maintaining postoperative disc space height, and achieving desirable clinical outcomes in patients who undergo TLIF with pedicle screw fixation. The advantages of PEEK cages include a lower incidence of subsidence and their radiolucency, which permits easier visualization of bone growth.


2006 ◽  
Vol 5 (3) ◽  
pp. 228-233 ◽  
Author(s):  
Sang-Ho Lee ◽  
Byung-Uk Kang ◽  
Sang Hyeop Jeon ◽  
Jong Dae Park ◽  
Dae Hyeon Maeng ◽  
...  

Object The aim of this study was to evaluate the efficacy of anterior lumbar interbody fusion (ALIF) augmented by percutaneous pedicle screw fixation (PSF) for revision surgery in the lumbar spine and to determine the prognostic factors affecting surgical outcomes. Methods The population included 54 consecutively treated patients in whom revision surgery involving ALIF with PSF was performed between 2001 and 2004. There were 22 men and 32 women, whose mean age was 59.5 years (range 25–78 years). The diagnoses prior to revision ALIF were as follows: degenerative disc disease in 25 patients, instability/spondylolisthesis in 15, recurrent disc herniation in seven, and pseudarthrosis in seven. The mean follow-up period was 24 months (range 12–52 months). The mean visual analog scale score for back and leg pain decreased, respectively, from 7.8 to 2.3 and 8.0 to 2.3 (p < 0.001). The mean Oswestry Disability Index score improved from 70 to 25% (p < 0.001). Radiological evidence of fusion was noted in 52 of 54 patients. The mean preoperative segmental lordosis, whole lumbar lordosis, and sacral tilt were 15.2, 35.5, and 28.3°, respectively; these values were significantly increased to 20.4, 40.7, and 31.4°, respectively, after revision surgery (p < 0.001). The increase in sacral tilt was positively correlated with improvement in back pain (p = 0.028) and functional status (p = 0.025). Conclusions The results demonstrate that ALIF followed by PSF can be an effective alternative in revision surgery of the lumbosacral spine in selected cases. Not only can solid fusion be achieved, sagittal alignment can also be restored in the majority of patients.


2021 ◽  
Author(s):  
Yichuan Qin ◽  
Bin Zhao ◽  
Jie Yuan ◽  
Chaojian Xu ◽  
Junqiang Su ◽  
...  

Abstract Background: The influence of cage position on postoperative cage subsidence has been paid increasing attention. The best cage position in oblique lumbar interbody fusion (OLIF) is still unclear. This study aimed to evaluate the biomechanical effects of different cage positions with stand-alone (SA) methods and bilateral pedicle screw fixation (BPSF) in the osteoporotic lumbar spine after OLIF.Methods: A finite element (FE) model of an intact L3-L5 lumbar spine was constructed. After validation, an osteoporosis model (OP) was constructed by assigning osteoporotic material properties. SA models (SA1, SA2, SA3) and BPSF models (BPSF1, BPSF2, BPSF3) in which a cage was placed in the anterior, middle and posterior third of the L5 superior endplate (SEP) were constructed at the L4-L5 segment of the OP. The L4-L5 range of motion (ROM), the stress of the L5 SEP, the stress of the cage and the stress of fixation were compared among the different models.Results: According to the degree of ROM of L4-L5, the stress of the L5 SEP and the stress of the cage for most physiological motions, the SA and BPSF models were ranked as follows: SA2<SA1<SA3, BPSF2<BPSF1<BPSF3. In BPSF2, the stress of fixation was minimal in most motions. At the same cage position, the ROM of L4-L5, the stress of the L5 SEP and the stress of the cage in the BPSF models were significantly reduced compared with those in SA models; compared with SA2, BPSF2 had a maximum reduction of 83.24%, 70.71% and 73.52% in these parameters, respectively.Conclusions: Placing the cage in the middle third of the L5 SEP for OLIF could reduce the maximum stresses of the L5 SEP, the cage and the fixation, which may reduce the risk of postoperative cage subsidence, endplate collapse and fixation fracture in the osteoporotic lumbar spine. Compared with SA OLIF, BPSF could provide sufficient stability for the surgical segment and may reduce the incidence of the aforementioned complications.


2009 ◽  
Vol 10 (6) ◽  
pp. 610-616 ◽  
Author(s):  
Sung Hun Park ◽  
Woo Min Park ◽  
Cheul Woong Park ◽  
Kwan Soo Kang ◽  
Young Keun Lee ◽  
...  

Object The purpose of this study was to determine whether anterior lumbar interbody fusion (ALIF) followed by percutaneous translaminar facet screw fixation is effective in elderly patients with degenerative spinal disease. Methods Twenty-nine patients > 60 years old who underwent ALIF with percutaneous translaminar facet screw fixation from January to June 2004 were studied. The radiological and clinical data of these patients were collected and analyzed. The mean follow-up period was 14.6 months (range 12–17 months). Results The mean preoperative, immediate postoperative, and 6- and 12-month postoperative posterior disc heights were 7.1, 11.6, 9.8, and 9.8 mm, respectively. Subsidences of posterior disc height > 20% developed in 9 patients (30%). The significant risk factor for subsidence was found to be 2-level operations (p = 0.023). The mean preoperative Oswestry Disability Index score and visual analog scale scores for the back and leg were 24.4, 6.6, and 7.5, respectively, and improved postoperatively to 14.2, 1.5, and 1.8, respectively. Conclusions Minimally invasive ALIF followed by percutaneous translaminar facet screw fixation was performed as a minimally invasive surgical technique in elderly patients. However, in certain circumstances such as multilevel operations or in patients with severe osteoporosis, significant cage subsidence can develop.


2010 ◽  
Vol 12 (5) ◽  
pp. 525-532 ◽  
Author(s):  
Kyeong Hwan Kim ◽  
Sang-Ho Lee ◽  
Dong Yeob Lee ◽  
Chan Shik Shim ◽  
Dae Hyeon Maeng

Object The purpose of the present study was to evaluate the efficacy of anterior polymethylmethacrylate (PMMA) cement augmentation in instrumented anterior lumbar interbody fusion (ALIF) for patients with osteoporosis. Methods Sixty-two patients with osteoporosis who had undergone single-level instrumented ALIF for spondylolisthesis and were followed for more than 2 years were included in the study. The patients were divided into 2 groups: instrumented ALIF alone (Group I) and instrumented ALIF with anterior PMMA augmentation (Group II). Sixty-one patients were interviewed to evaluate the clinical results, and plain radiographs and 3D CT scans were obtained at the last follow-up in 46 patients. Results The mean degree of cage subsidence was significantly higher in Group I (19.6%) than in Group II (5.2%) (p = 0.001). The mean decrease of vertebral body height at the index level was also significantly higher in Group I (10.7%) than in Group II (3.9%) (p = 0.001). No significant intergroup differences were observed in the incidence of radiographic adjacent-segment degeneration (ASD) or in terms of pain and functional improvement. The incidences of clinical ASD (23% in Group I and 10% in Group II) were not significantly different. There was 1 case of nonunion and 3 cases of screw migration in Group I, but none resulted in implant failure. Conclusions Anterior PMMA augmentation during instrumented ALIF in patients with osteoporosis was useful to prevent cage subsidence and vertebral body collapse. In addition, PMMA augmentation did not increase the nonunion rate and incidence of ASD.


2021 ◽  
Vol 15 (1) ◽  
pp. 35-40
Author(s):  
Kyriakos Kitsopoulos ◽  
Bernd Wiedenhoefer ◽  
Stefan Hemmer ◽  
Christoph Fleege ◽  
Mohammad Arabmotlagh ◽  
...  

Background: Compared with static cages, expandable cages for Transforaminal Lumbar Interbody Fusion (TLIF), are thought to require less posterior bony removal and nerve root retraction. They may allow the creation of a greater lordotic angle and lordosis restoration. Objective: This study investigated whether TLIF using an expandable lordotic interbody cage facilitates an improvement in both segmental lordosis and the restoration of intradiscal height. Methods: A total of 32 patients with 40 operated segments underwent TLIF surgery for lumbar degenerative disc disease and were consecutively included in this prospective observational study. Of those patients, 25 received monosegmental treatment, six were treated bisegmentally, and one was treated trisegmentally. All patients were assessed clinically and radiographically preoperatively, as well as one week, six months, and two years postoperatively. Results: Two patients required revision for screw loosening and pseudarthrosis. In four patients, the endplate was violated intraoperatively due to cage placement. Postoperatively, cage subsidence was observed in four patients. Significant improvement in the mean degree of spondylolisthesis was noted at the two-year mark. Mean segmental lordosis improved postoperatively. A significant increase in mean disc height of the treated segment was also found. Overall, with the exception of pain, no significant clinical or radiographic changes were reported between the first postoperative week and the two-year year follow-up mark. The mean pain, functional, and quality of life outcomes improved significantly from the preoperative to postoperative period, with no deterioration between six months and two years. Conclusion: This study demonstrates that favorable outcomes can be achieved by using an expandable titanium cage in TLIF procedures.


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