Discussion

In this systematic review and meta-analysis of 878,116 adult patients undergoing lumbar spinal surgery across four studies, we found that individuals with IBD had significantly higher odds of experiencing adverse postoperative outcomes compared to non-IBD controls. Pooled analyses revealed increased risks of both serious and minor complications, including surgical wound infections, VTE/PE, pneumonia, UTIs, AKI, MI, sepsis and need for blood transfusion. Across specific outcomes, these risks often approached or exceeded a 2-fold increase in odds compared to non-IBD patients and warrant clinical consideration. These risks are more than double the odds compared to non-IBD patients and warrant strong clinical consideration. Although all-cause 90-day hospital readmission rates were not significantly different between groups, emergency department returns were markedly higher in IBD patients. However, given the considerable heterogeneity, pooled effects should be taken as exploratory rather than confirmatory estimates.

The increased odds of infectious complications among patients with IBD are well documented in the literature and are biologically plausible given the immunosuppressive nature of therapies commonly used in IBD management. ^{Reference Law, Bell, Koh, Bao, Jairath and Narula16–Reference Liu, Deng and Chen18} Furthermore, it has been established that having active IBD increases the risk of development of various infections. ^{Reference Coward, Benchimol and Kuenzig27–29} Corticosteroids and anti-TNF agents are independently associated with a significantly increased risk of postoperative infections, particularly intra-abdominal infections. ^{Reference Hanzel, Almradi and Istl15,Reference Law, Bell, Koh, Bao, Jairath and Narula16,Reference Dave, Purohit, Razonable and Loftus30} These risks are amplified when patients are on combination immunosuppressive regimens. ^{Reference Beaugerie and Kirchgesner31} In our analysis, IBD patients had significantly higher odds of surgical site infection (OR = 1.21), pneumonia (OR = 2.31), UTI (OR = 2.29) and sepsis compared to non-IBD controls, highlighting the clinical relevance of these prior findings. Our findings are consistent with evidence from multiple large cohort studies and meta-analyses in non-spinal IBD surgery, which demonstrate similarly elevated perioperative complication risks in this population, ^{Reference Law, Bell, Koh, Bao, Jairath and Narula16,Reference McKenna and Lightner17} as well as across major abdominal and orthopedic procedures. ^{Reference Epple32,Reference Long, Martin, Sandler and Kappelman33} In addition, these findings are consistent with broader literature across other surgical contexts. For example, patients with IBD undergoing arthroplasty or bariatric surgery also demonstrate increased risk of infectious complications. ^{Reference Epple32,Reference Long, Martin, Sandler and Kappelman33}

Similarly, we found that IBD patients had significantly higher odds of developing AKI (OR = 1.91) and requiring blood transfusion (OR = 1.64) following any form of lumbar spine surgery. These associations may be mechanistically explained by chronic inflammation, hypovolemia and use of nephrotoxic medications in IBD, which predispose patients to renal injury, as well as anemia of chronic disease and nutrient malabsorption, which increase the likelihood of transfusion. ^{Reference Yu, Jung and Lee34–Reference Rahal, Karaoui, Mailhac, Tamim and Shaib36} These results highlight a substantial burden of systemic complications in this surgical population and align with prior evidence on the physiologic vulnerabilities associated with IBD. ^{Reference Xu, Ding, Cheng, Yang and Zhang37–Reference Liu, Zhang and Ye39} Population-based studies have also confirmed an increased risk of AKI in IBD patients, particularly following colectomy or major surgery, ^{Reference Yang, Ludvigsson, Olén, Sjolander and Carrero38–Reference Antunes, Neto and Nascimento40} and prior research has shown that IBD patients undergoing surgical procedures are more likely to require perioperative blood transfusions, especially in the presence of preoperative anemia or active disease. ^{Reference Antunes, Neto and Nascimento40–Reference Abeysiri, Chau and Richards45}

Our findings regarding cardiovascular complications also align with the broader IBD literature, which has consistently shown increased risks of ischemic stroke, MI, VTE/PE and systemic infections in patients with IBD, even outside the operative setting. ^{Reference Aniwan, Pardi, Tremaine and Loftus46–Reference Sun, Halfvarson and Appelros48} In our analysis, IBD patients had significantly higher odds of MI (OR = 1.76) following lumbar spine surgery. These results are supported by prior epidemiologic studies in non-operative IBD cohorts, which demonstrate a modest but persistent long-term increase in ischemic cardiovascular events over years of follow-up, independent of traditional cardiovascular risk factors. ^{Reference Aniwan, Pardi, Tremaine and Loftus46–Reference Sun, Halfvarson and Appelros48}

Despite the significantly elevated rates of surgical complications in IBD patients, the lack of a statistically significant difference in 90-day hospital readmission rates is noteworthy. In our analysis, readmission rates did not differ between groups (OR = 1.08), suggesting no meaningful increase in re-hospitalization among IBD patients. However, as this observation may reflect measurement limitations and heterogeneity, no causal inference should be drawn. In addition, because large datasets code administrative outcomes, such as readmission, more reliably than clinical complications, the true magnitude of postoperative morbidity in IBD patients may be underestimated by readmission metrics alone. Prior studies have similarly shown that IBD patients often do not experience increased hospital readmissions despite higher postoperative morbidity, even when comorbidities and disease severity are controlled for. ^{Reference Nguyen, Bollegala and Chong49–Reference Micic, Gaetano and Rubin51} This apparent disconnect may reflect the success of perioperative planning, early discharge protocols or outpatient complication management. However, the increased emergency department return rate observed in our study (OR = 2.44) suggests that IBD patients may still experience early postoperative challenges that are not fully captured by readmission metrics. In a recent multivariable prediction model developed among adults hospitalized for acute UC-related indications, Dziegieleski et al. have suggested that for UC patients, gastroenterologist consultation within the prior year (adjusted OR [aOR] 0.11, 95% CI, 0.04–0.39), male sex (aOR 3.27, 95% CI, 1.33–8.05), length of stay (OR 0.94, 95% CI, 0.88–1.01) and narcotic prescription at discharge (OR 1.96, 95% CI, 0.73–5.27) as significant predictors of 90-day re-hospitalization. ^{Reference Dziegielewski, Gupta and Lombardi52} Patients undergoing lumbar surgery should have close follow-up if they are discharged with narcotics.

There is also a clinically meaningful overlap between IBD and AS, a spondyloarthritis characterized by axial skeletal inflammation. AS occurs more frequently in patients with IBD, and subclinical gut inflammation is common among individuals with AS. Shared immunologic pathways, including the IL-23/IL-17 axis and TNF-α, may contribute both to spinal vulnerability and heightened perioperative inflammatory responses. These mechanistic links underscore that spinal pathology in IBD may be influenced not only by general systemic inflammation but also by coexisting spondyloarthropathic processes. ^{Reference Mowlah and Soldera53–Reference Subramanian, Saxena, Kang and Pollok55}

Only two studies ^{Reference Seddio, Katsnelson and Smith-Voudouris24,Reference Zhang, Chi and Manley26} provided data on surgical treatment outcomes such as reoperation rates, and other important outcomes, including functionality, long-term pain and motor strength, were not described in any of the studies. Regarding surgical outcomes, existing studies report mixed findings depending on the type of spinal procedure. ^{Reference Seddio, Katsnelson and Smith-Voudouris24,Reference Zhang, Chi and Manley26} Seddio et al. found no significant difference in five-year reoperation-free survival between IBD and non-IBD patients undergoing posterior lumbar fusion, suggesting that the presence of IBD did not negatively affect long-term outcomes in fusion surgery. ^{Reference Seddio, Katsnelson and Smith-Voudouris24} In contrast, Zhang et al. reported that patients with IBD who underwent lumbar discectomy experienced significantly higher rates of revision discectomy within two years and were more likely to require subsequent lumbar fusion within three years. Additionally, although not statistically significant, revision procedures occurred earlier on average in the IBD cohort, by approximately 27.3 days for discectomy and 54.5 days for fusion. ^{Reference Zhang, Chi and Manley26}

Overall, the four included studies differed in design, data source and clinical questions, which likely contributed to heterogeneity across pooled outcomes. Seddio et al. ^{Reference Seddio, Katsnelson and Smith-Voudouris24} used the PearlDiver database to examine single-level posterior lumbar fusion and demonstrated increased 90-day adverse events and emergency department visits, but no difference in 5-year reoperation rates, suggesting that short-term morbidity does not necessarily translate to reduced long-term surgical durability. In contrast, Tanenbaum et al., ^{Reference Tanenbaum, Kha, Benzel, Steinmetz and Mroz14} using the NIS, evaluated only in-hospital complications and found no increased odds of perioperative complications after lumbar fusion, highlighting how inpatient-only surveillance can underestimate early postoperative morbidity. Elali et al. ^{Reference Elali, Nian, Rodriguez, Conway, Saleh and Razi25} analyzed 1–2 level lumbar fusions and reported higher rates of medical complications, readmissions and length of stay in IBD patients, aligning more closely with Seddio et al. ^{Reference Seddio, Katsnelson and Smith-Voudouris24} but differing from Tanenbaum et al. ^{Reference Tanenbaum, Kha, Benzel, Steinmetz and Mroz14} due to broader 90-day surveillance and inclusion of hospital cost data. Zhang et al. ^{Reference Zhang, Chi and Manley26} focused exclusively on lumbar discectomy and uniquely identified higher revision and recurrence rates in IBD patients, suggesting that the impact of IBD may differ by procedure type. Together, these study-specific differences demonstrate that the relationship between IBD and postoperative outcomes may vary depending on database structure, timing of outcome capture (in-hospital vs 90-day vs multi-year) and the underlying surgical procedure performed.

These findings suggest that IBD may not universally impair surgical durability but could be associated with higher reoperation risk in specific contexts such as non-fusion procedures. However, given the underlying bone mineralization abnormalities and systemic inflammation in IBD, ^{Reference Aberra, Lewis, Hass, Rombeau, Osborne and Lichtenstein56,Reference Qaiyum, Lim and Inman57} it is biologically plausible that fusion procedures may also carry elevated mechanical or hardware-related risks. The earlier and more frequent revisions seen in discectomy patients with IBD may be attributable to systemic inflammation, delayed healing, corticosteroid and other medication utilization or other disease-related factors. ^{Reference Mowlah and Soldera53} This highlights the need to consider IBD status in preoperative planning, particularly when selecting a surgical approach and counseling patients on postoperative expectations. Steroids and immunosuppressive therapies may play a key role here, as chronic and high-dose corticosteroid use is associated with impaired wound healing and increased infectious complications, while long-term biologic therapy has been linked to elevated postoperative infection risk in IBD. ^{Reference Wang, Armstrong and Armstrong58,Reference Baker and George59} However, none of the included studies provided granular data on steroid dose, duration or immunotherapy timing, limiting our ability to quantify their contribution to postoperative spine-surgery risk. This represents an important area for future study, particularly given the widespread use of these therapies in IBD management. ^{Reference Akiyama, Alshehri and Suzuki60}

Overall, these findings serve as an important reminder that patients with IBD face elevated medical and surgical risks when undergoing lumbar spine procedures. Treating surgeons may consider incorporating preoperative optimization, including assessment and stabilization of active inflammation, nutritional status and bone health, careful review of medications that impair wound healing (e.g., corticosteroids, biologics, NSAIDs) and early involvement of anesthesia and gastroenterology for perioperative planning. Postoperatively, increased vigilance for infection, delayed wound healing, dehydration and potential fusion-related complications is warranted.

Notably, follow-up time was limited to five years in Seddio et al. and three years in Zhang et al. ^{Reference Seddio, Katsnelson and Smith-Voudouris24,Reference Zhang, Chi and Manley26} Further investigation into longer-term outcomes of lumbar spine surgery in patients with IBD should be considered to better understand the durability of surgical interventions in this population, as well as potential disease-specific factors that may influence recovery, recurrence and overall quality of life. It is important to note that data were only available for all-cause hospital readmission and emergency department visits. It is unclear the number of patients who returned to the hospital for surgery-specific concerns, such as postoperative complications or treatment failure. Future research should be considered to evaluate the rate and nature of surgery-related returns to care, including infections, hardware issues, neurologic deterioration or inadequate symptom relief. A clearer understanding of these events would help delineate true surgical morbidity from unrelated health issues, allowing for more accurate assessment of procedure safety and efficacy.

This review has several limitations. All included studies were retrospective cohort analyses based on large administrative datasets, which are susceptible to misclassification, coding bias and residual confounding. We also lacked granular data on multiple domains, including disease activity, IBD subtype (e.g., CD vs. UC), surgical procedure type (e.g., decompression vs. fusion), immunosuppressive medication type, nutritional status and surgical complexity, which are all key modifiers of postoperative outcomes. For example, prior research suggests corticosteroid dosage is a critical determinant of postoperative infectious risk, ^{Reference Orgun, Nordestgaard, Poulsen, Gogenur and Ellervik54–Reference Aberra, Lewis, Hass, Rombeau, Osborne and Lichtenstein56} but we were unable to stratify by dose due to data limitations. Additionally, substantial statistical heterogeneity was present across many outcomes, even after sensitivity analyses were conducted. Finally, the small number of included studies for several outcomes limited our ability to perform subgroup analyses by procedure type or IBD subtype and precluded a formal publication bias assessment in most cases. Prospective cohort studies with detailed clinical data and patient-reported outcomes are needed to better understand surgical candidacy, optimize perioperative care and personalize risk stratification.

To our knowledge, this is the first meta-analysis to comprehensively evaluate lumbar spine surgery outcomes in IBD patients, incorporating 15,763 individuals with IBD across multiple large-scale databases. By examining a wide range of complications, this study provides a nuanced understanding of postoperative risk in this medically complex population.