Age, body mass index, and osteoporosis are more predictive than imaging for adjacent-segment reoperation after lumbar fusion
- Department of Neurosurgery, Lahey Clinic, Burlington, Massachusetts, United States.
- Department of Neurosurgery, University of Utah, Clinical Neurosciences Center, Salt Lake City, Utah, United States.
Andrew Y. Yew, MD, Department of Neurosurgery, Lahey Clinic, Burlington, Massachusetts, United States.
DOI:10.25259/SNI_667_2021Copyright: © 2021 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Nii-Kwanchie Ankrah1, Ilyas M. Eli2, Subu N. Magge1, Robert G. Whitmore1, Andrew Y. Yew1. Age, body mass index, and osteoporosis are more predictive than imaging for adjacent-segment reoperation after lumbar fusion. 06-Sep-2021;12:453
How to cite this URL: Nii-Kwanchie Ankrah1, Ilyas M. Eli2, Subu N. Magge1, Robert G. Whitmore1, Andrew Y. Yew1. Age, body mass index, and osteoporosis are more predictive than imaging for adjacent-segment reoperation after lumbar fusion. 06-Sep-2021;12:453. Available from: https://surgicalneurologyint.com/surgicalint-articles/11088/
Background: Adjacent-segment disease (ASD) is a well-described long-term complication after lumbar fusion. There is a lack of consensus about the risk factors for development of ASD, but identifying them could improve surgical outcomes. Our goal was to analyze the effect of patient characteristics and radiographic parameters on the development of symptomatic ASD requiring revision surgery after posterior lumbar fusion.
Methods: In this retrospective cohort study, we identified patients who underwent lumbar fusion surgery and revision surgery from May 2012 to November 2018 using an institutional lumbar fusion registry. Patients having both pre- and post-operative upright radiographs were included in the study. Revision surgeries for which the index operation was performed at an outside hospital were excluded from analysis. Univariate analysis was conducted on candidate variables, and variables with P
Results: Of the 106 patients identified, 21 required reoperation (29 months average follow-up). Age >65 years (OR 4.14, 95% CI 1.46–11.76, P= 0.008), body mass index (BMI) >34 (OR 1.13, 95% CI 1.04–1.23, P = 0.004), and osteoporosis (OR 14, 95% CI 1.38–142.42, P = 0.03) were independent predictors of reoperation in the multivariate analysis. Increased facet diastasis at fusion levels (OR 0.60, 95% CI 0.42–0.85, P = 0.004) was associated with reduced reoperation rates. Change in segmental LL at the index operation level, rostral and caudal facet diastasis, vacuum discs, and T2 hyperintensity in the facets were not predictors of reoperation.
Conclusion: Age >65, BMI >34, and osteoporosis were independent predictors of adjacent-segment reoperation after lumbar spinal fusion.
Keywords: Adjacent segment disease, Fusion, Imaging, Lumbar lordosis, Reoperation, Spine
Lumbar instrumented fusion is a common procedure for the treatment of a variety of degenerative spinal disorders including lumbar spondylolisthesis and is supported by multiple guidelines.[
Current surgical techniques are highly effective in achieving improved patient outcomes with high rates of bony fusion, up to 90–95%.[
Adjacent-segment degeneration is defined based on degenerative changes seen at adjacent segments on radiological imaging, whereas adjacent-segment disease (ASD) requires both radiologic degeneration and clinical symptoms.[
The exact pathogenesis of ASD is yet to be elucidated. Numerous patient, radiographic, and clinical risk factors have been published, but most lack consensus. Factors reported in the literature include age, female sex, osteoporosis, posterior interbody fusion, fusion length, pre-existing adjacent-level disc degeneration, sagittal alignment, and lumbar stenosis.[
An institutional review board approved retrospective single-center study was performed using the lumbar fusion registry at our institution to identify patients who underwent index lumbar fusion surgery with instrumentation and their revision surgery here from May 2012 to November 2018. Patients older than 18 years of age who underwent 1st-time lumbar fusion and had pre- and postoperative upright lumbar radiographs were included in the study. Patients who lacked pre- or post-operative radiographs or who underwent revision surgeries for which the index operation was performed at an outside hospital were excluded from the study. Patients who fit these criteria but did not require revision for ASD were used for comparison.
Variables and outcomes
Candidate variables obtained from patient records included sex, age, diagnosis of osteoporosis, number of levels fused, pre- and post-operative segmental lordosis at the index fusion level and adjacent segments, preoperative T2 signal hyperintense signal in the facets, preoperative facet diastasis (the maximum distance between the inferior articular process and the superior articular process for a given joint measured in millimeters), preoperative disc space height, pre- and postoperative lumbar lordosis (LL), amount of disc space distraction if interbody placed, change in pre- versus post-operative segmental lordosis at the fusion levels, history of trauma, and body mass index (BMI).
Age >65 years was considered elderly. For BMI, we used the standard accepted medical definition to classify patients: overweight (BMI 25–29.9), mild obesity (30–34.9), moderate obesity (35–39.9), and severe obesity (≥40).[
Univariate analysis was conducted on candidate variables. Candidate variables with P < 0.2 were selected for multivariate logistic regression. Data were analyzed using standard SPSS statistical software 25 (IBM Corp, Armonk, New York, USA). Mean values for continuous variables were compared using t-test whereas categorical variables were compared using Chi-squared. P < 0.05 was deemed statistically significant.
A total of 106 patients who underwent lumbar fusion and met the inclusion criteria for the study were identified. Of these, 21 (19.8%) required revision surgery. The average length of follow-up was 29 months after the index operation.
The mean age was 60.2 years for the non-ASD group (no revision surgery) and 67.1 years for the ASD group (P = 0.02) [
The radiographic characteristics of patients with and without ASD after posterior lumbar fusion are shown in
Intervertebral disc space height measurements did not differ significantly between the two groups, either before or after surgery, suggesting that this study lacked any power to detect whether intervertebral disc height was a predictor or not [
For index-level segmental lordosis, the mean pre- and postoperative values were only marginally different between patients who required reoperation and those who did not (P > 0.05 for both). Unsurprisingly, change in segmental lordosis was not statistically significant. Comparing those whose segmental lordosis remained the same and those who had a decrease versus patients who had an increase in segmental lordosis, there was no statistically significant difference in reoperation rates (P = 0.47). When comparing the rostral adjacent segment pre- and post-operative segmental lordosis, there was no statistically significant difference between the two groups. The change in segmental lordosis between both groups was also not statistically significant. When categorized into same versus decrease versus increase in segmental lordosis, there was again no statistically significant difference in reoperation rates (P = 0.63). Caudal pre- and post-operative segmental lordosis was not significantly different between the two groups with P = 0.08 and P = 0.03, respectively. Again, when the difference in caudal pre- and post-operative segmental lordosis is categorized into same versus decrease versus increase in lordosis, univariate analysis showed no statistically significant difference, with P = 0.12 [
Variables with P < 0.2 were used in the binary logistic regression analysis [
In this study, we retrospectively reviewed our institutional lumbar fusion registry and identified 106 patients who met inclusion criteria to investigate predictors of ASD. Our main aim was to assess clinical and radiographic risk factors that contributed to the development of ASD. According to our results, age >65 years, BMI >34, and osteoporosis were independent predictors of reoperation whereas radiographic measurements and changes were not overall predictors of reoperation.
There was no statistically significant difference in the pre- and post-operative LL in either group [
Evaluation of segmental LL in our study found that the mean angles were similar in the non-ASD and ASD groups, with no significant change in pre- and post-operative segmental LL. Similarly, there was no significant difference in rostral segmental lordosis between the two groups, although there was a significant difference in the caudal postoperative segmental lordosis between the two groups, with the mean segmental LL higher in non-ASD group and less likelihood of reoperation with a higher segmental LL. However, on multivariate analysis, this did not turn out to be an independent predictor of reoperation.
There was no statistically significant change in disc space height at the level of surgery, or at the rostral and caudal adjacent levels. Although the caudal pre- and post-operative disc space measurements fulfilled our criteria for inclusion in the logistic regression, they were not significant predictors in that analysis. Similarly, Makino et al.[
According to our multivariate analysis, age >65 years was associated with an increased risk of developing ASD requiring surgery. The literature suggests mixed results on the role of age in predicting ASD in general. Several studies indicate age as a risk factor,[
BMI is an objective measure that can be followed in relation to formation of ASD. Higher BMI results in increased stress on the lumbar spine, which can accelerate disc degeneration caused by the increased burden to absorb the loading forces.[
We found that osteoporosis was associated with an increased risk of reoperation, which is consistent with findings seen by Hashimoto et al.[
This was a retrospective single-institution study with a small number of patients that had reoperation and thus had the inherent limitations of that study type. This may limit the generalizability of the findings. Data were unavailable in some patients, and some data points were not collected because of either loss of data or poor image quality. The length of follow-up was shorter in the non-ASD group, which may be a potential source of bias, as longer follow-up generally results in higher reoperation rates because of the natural history of lumbar degenerative disease. The accuracy of measurement of angles and disc space may have been compromised if a slight movement led to a change in measured values. We were unable to carry out analysis on pelvic parameters because the imaging studies did not include the femoral heads.
In this study, we retrospectively reviewed 106 patients who underwent lumbar fusion, of which 21 (19.8%) of the patients required revision surgery for the treatment of ASD. We found that age >65, BMI >34, and osteoporosis were independent predictors of ASD leading to reoperation.
This study was completed under ethical guidelines and was approved by the institutional review board.
Institutional Review Board (IRB) permission obtained for the study.
There are no conflicts of interest.
1. Alentado VJ, Lubelski D, Healy AT, Orr RD, Steinmetz MP, Benzel EC. Predisposing characteristics of adjacent segment disease after lumbar fusion. Spine (Phila Pa 1976). 2016. 41: 1167-72
2. Arif S, Brady Z, Enchev Y, Peev N. Is fusion the most suitable treatment option for recurrent lumbar disc herniation? A systematic review. Neurol Res. 2020. 42: 1034-42
3. Bagheri SR, Alimohammadi E, Froushani AZ, Abdi A. Adjacent segment disease after posterior lumbar instrumentation surgery for degenerative disease: Incidence and risk factors. J Orthop Surg (Hong Kong). 2019. 27:
4. . Clinical guidelines on the identification evaluation, and treatment of overweight and obesity in adults-the evidence report. National institutes of health. Obes Res. 1998. 6: 51S-209S
5. Cobb J. Outline for the study of scoliosis. Am Acad Orthop Surg Instr Course Lect. 1948. 5: 261-75
6. Dunlop RB, Adams MA, Hutton WC. Disc space narrowing and the lumbar facet joints. J Bone Joint Surg Br. 1984. 66: 706-10
7. Eck JC, Sharan A, Ghogawala Z, Resnick DK, Watters WC, Mummaneni PV. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine Part. 7 Lumbar fusion for intractable low-back pain without stenosis or spondylolisthesis. J Neurosurg Spine. 2014. 21: 42-7
8. Flippin M, Harris J, Paxton EW, Prentice HA, Fithian DC, Ward SR. Effect of body mass index on patient outcomes of surgical intervention for the lumbar spine. J Spine Surg. 2017. 3: 349-57
9. Groff MW, Dailey AT, Ghogawala Z, Resnick DK, Watters WC, Mummaneni PV. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine Part. 12 Pedicle screw fixation as an adjunct to posterolateral fusion. J Neurosurg Spine. 2014. 21: 75-8
10. Harrop JS, Youssef JA, Maltenfort M, Vorwald P, Jabbour P, Bono CM. Lumbar adjacent segment degeneration and disease after arthrodesis and total disc arthroplasty. Spine (Phila Pa 1976). 2008. 33: 1701-7
11. Hashimoto K, Aizawa T, Kanno H, Itoi E. Adjacent segment degeneration after fusion spinal surgery-a systematic review. Int Orthop. 2019. 43: 987-93
12. Kong C, Li X, Sun X, Ding J, Guo M, Lu S. Complications in elderly patients undergoing lumbar arthrodesis for spinal stenosis. World Neurosurg. 2019. 132: e949-55
13. Lee JC, Choi SW. Adjacent segment pathology after lumbar spinal fusion. Asian Spine J. 2015. 9: 807-17
14. Lee JC, Kim Y, Soh JW, Shin BJ. Risk factors of adjacent segment disease requiring surgery after lumbar spinal fusion: Comparison of posterior lumbar interbody fusion and posterolateral fusion. Spine (Phila Pa 1976). 2014. 39: E339-45
15. Makino T, Honda H, Fujiwara H, Yoshikawa H, Yonenobu K, Kaito T. Low incidence of adjacent segment disease after posterior lumbar interbody fusion with minimum disc distraction: A preliminary report. Medicine (Baltimore). 2018. 97: e9631
16. Maragkos GA, Atesok K, Papavassiliou E. Prognostic factors for adjacent segment disease after L4-L5 lumbar fusion. Neurosurgery. 2020. 86: 835-42
17. Martin BI, Mirza SK, Spina N, Spiker WR, Lawrence B, Brodke DS. Trends in lumbar fusion procedure rates and associated hospital costs for degenerative spinal diseases in the United States, 2004 to 2015. Spine (Phila Pa 1976). 2019. 44: 369-76
18. Mummaneni PV, Dhall SS, Eck JC, Groff MW, Ghogawala Z, Watters WC. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine Part. 11 Interbody techniques for lumbar fusion. J Neurosurg Spine. 2014. 21: 67-74
19. Ou CY, Lee TC, Lee TH, Huang YH. Impact of body mass index on adjacent segment disease after lumbar fusion for degenerative spine disease. Neurosurgery. 2015. 76: 396-401
20. Park P, Garton HJ, Gala VC, Hoff JT, McGillicuddy JE. Adjacent segment disease after lumbar or lumbosacral fusion: Review of the literature. Spine (Phila Pa 1976). 2004. 29: 1938-44
21. Phan K, Nazareth A, Hussain AK, Dmytriw AA, Nambiar M, Nguyen D. Relationship between sagittal balance and adjacent segment disease in surgical treatment of degenerative lumbar spine disease: Meta-analysis and implications for choice of fusion technique. Eur Spine J. 2018. 27: 1981-91
22. Puvanesarajah V, Cancienne JM, Werner BC, Jain A, Singla A, Shimer AL. Perioperative complications associated with posterolateral spine fusions: A study of elderly medicare beneficiaries. Spine (Phila Pa 1976). 2018. 43: 16-21
23. Radcliff KE, Kepler CK, Jakoi A, Sidhu GS, Rihn J, Vaccaro AR. Adjacent segment disease in the lumbar spine following different treatment interventions. Spine J. 2013. 13: 1339-49
24. Resnick DK, Watters WC, Mummaneni PV, Dailey AT, Choudhri TF, Eck JC. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine Part. 10 Lumbar fusion for stenosis without spondylolisthesis. J Neurosurg Spine. 2014. 21: 62-6
25. Resnick DK, Watters WC, Sharan A, Mummaneni PV, Dailey AT, Wang JC. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part. 9 Lumbar fusion for stenosis with spondylolisthesis. J Neurosurg Spine. 2014. 21: 54-61
26. Saavedra-Pozo FM, Deusdara RA, Benzel EC. Adjacent segment disease perspective and review of the literature. Ochsner J. 2014. 14: 78-83
27. Scemama C, Magrino B, Gillet P, Guigui P. Risk of adjacent-segment disease requiring surgery after short lumbar fusion: Results of the french spine surgery society series. J Neurosurg Spine. 2016. 25: 46-51
28. Vazifehdan F, Karantzoulis VG, Igoumenou VG. Sagittal alignment assessment after short-segment lumbar fusion for degenerative disc disease. Int Orthop. 2019. 43: 891-8
29. Wang H, Ma L, Yang D, Wang T, Liu S, Yang S. Incidence and risk factors of adjacent segment disease following posterior decompression and instrumented fusion for degenerative lumbar disorders. Medicine (Baltimore). 2017. 96: e6032
30. Wang JC, Dailey AT, Mummaneni PV, Ghogawala Z, Resnick DK, Watters WC. Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part. 8 Lumbar fusion for disc herniation and radiculopathy. J Neurosurg Spine. 2014. 21: 48-53
31. West JL, Bradford DS, Ogilvie JW. Results of spinal arthrodesis with pedicle screw-plate fixation. J Bone Joint Surg Am. 1991. 73: 1179-84
32. Zhong ZM, Deviren V, Tay B, Burch S, Berven SH. Adjacent segment disease after instrumented fusion for adult lumbar spondylolisthesis: Incidence and risk factors. Clin Neurol Neurosurg. 2017. 156: 29-34