Abstract
Background
Robotic-assisted surgery is increasingly available in rural Michigan, but outcomes in these populations remain unclear. National data suggest robotic colectomies are associated with improved outcomes compared with open procedures, but evidence for rural patients is limited. This study compared postoperative outcomes of open, laparoscopic, and robotic right colectomies among rural and urban Michigan residents.
Methods
The HCUP State Inpatient Sample (2016-2018) identified adults undergoing right colectomy. Rural and urban residence was classified using Urban Influence Codes (UIC); rural residence was defined as codes 3-12. Complications included prolonged ileus, pneumonia, surgical site infection, abscess, septicemia, hemorrhage/hematoma, urinary tract infection, in-hospital death, and length of stay ≥5 days. ICD-10 codes identified surgical approach. Logistic regression estimated adjusted odds ratios (aORs), controlling for demographic and clinical covariates.
Results
Among rural residents, minimally invasive approaches were associated with lower odds of complications than open surgery, with robotic procedures showing the lowest odds. Urban residents undergoing robotic colectomies experienced greater reductions in odds of pneumonia and urinary tract infections than rural residents.
Discussion
Minimally invasive right colectomy was associated with lower odds of complications compared with open surgery. Robotic techniques showed the most favorable outcomes, though benefits appeared greater among urban residents. These disparities may reflect institutional experience, infrastructure, or access to robotic platforms. Given the limitations of administrative data and observational design, results should be interpreted as associations rather than causation. Further studies incorporating hospital- and surgeon-level data and post-discharge outcomes are needed to clarify rural-urban differences and guide equitable surgical care.
Key Takeaways
• Among Michigan residents undergoing right colectomy, minimally invasive approaches—especially robotic—were associated with significantly lower odds of postoperative complications compared to open surgery. • Rural patients undergoing robotic colectomy had lower odds of complications than those receiving open or laparoscopic surgery, though urban patients experienced even greater benefit from robotic techniques. • These findings suggest potential geographic disparities in outcomes that may be influenced by differences in surgical expertise, hospital resources, and access to robotic technology.
Introduction
Right colectomies are a standard surgical treatment for a range of benign and malignant conditions, including inflammatory bowel disease, cecal volvulus, ischemia, trauma, infection, and colon cancer. 1 Since the early 1990s, minimally invasive approaches—primarily laparoscopic and, more recently, robotic surgery—have played an increasingly prominent role in colorectal operations.2-5 Robotic-assisted techniques offer potential ergonomic advantages over laparoscopy, including enhanced precision, instrument articulation, and surgeon comfort.6,7 The da Vinci® surgical system remains the most widely adopted robotic platform. 7
Several studies using national data sets have reported that robotic colectomies are associated with decreased postoperative complications, morbidity, and mortality compared to open surgery.2-4 However, comparisons between robotic and laparoscopic approaches have yielded mixed findings: some studies report no significant differences in postoperative outcomes, while others suggest a modest advantage for robotic procedures.2-4,8-15
Most of these studies originate from high-volume urban centers, where robotic surgery is more commonly performed and where surgeons often have specialized training.8,16 As robotic technology has become more widely available, its use has expanded into smaller, non-metropolitan regions, including across Michigan. 17 However, most existing literature focuses on urban patients or hospital-based outcomes.2-4,10-12 In contrast, there is limited research evaluating outcomes specifically among patients residing in rural areas—even though minimally invasive right colectomies remain commonly performed in these populations. 18
This study aims to compare postoperative complication rates following open, laparoscopic, and robotic right colectomies among patients residing in rural Michigan. Additionally, we evaluate whether the benefits observed with robotic surgery differ between rural and urban residents. To our knowledge, this is the first study to examine outcomes associated with minimally invasive right colectomy by surgical approach using a statewide data set stratified by patient rurality. Understanding these patterns may help guide equitable surgical planning and resource allocation for rural populations.
Methods
This study utilized the Michigan State Inpatient Database, part of the Healthcare Cost and Utilization Project (HCUP), for the years 2016 through 2018. 19 A total of 32 730 hospitalizations were identified with ICD-10 procedure codes corresponding to right colectomy. Patients under the age of 18 were excluded, resulting in an analytic sample of 32 579 adult cases. Among these, 5237 patients underwent an open right colectomy, 2151 underwent a laparoscopic procedure, and 25 191 underwent a robotic procedure.
Rural and urban residence was classified using the Urban Influence Codes (UIC) developed by the US Department of Agriculture Economic Research Service. 20 This system categorizes counties based on population size and proximity to metropolitan areas. For this study, rural residence was defined as UIC codes 3 through 12, indicating non-metropolitan areas. Based on this classification, 5353 hospitalizations (16.4% of the total sample) involved patients residing in rural areas. To allow for comparative analysis, urban residents undergoing similar procedures were also evaluated.
Demographic variables extracted from the data set included age, sex, and race. Socioeconomic status was approximated using the median household income for the patient’s ZIP code, categorized into quartiles. Patient comorbidities were assessed using ICD-10 codes mapped to the Charlson Comorbidity Index (CCI), a validated tool that assigns weighted scores to 17 chronic conditions to estimate overall disease burden. 21 A continuous CCI score was calculated for each patient.
Postoperative complications were identified using ICD-10 codes and included: prolonged ileus, pneumonia, surgical site infection, intra-abdominal abscess, septicemia, acute anemia, hemorrhage or hematoma, urinary tract infection, accidental puncture or laceration, in-hospital mortality, and prolonged length of stay (≥5 days).
Statistical analyses were conducted using IBM SPSS Statistics version 26.0. Descriptive comparisons across procedure types were made using chi-square tests for categorical variables and one-way ANOVA for continuous variables. Separate logistic regression models were used to estimate the adjusted odds ratio (aOR) of each complication for laparoscopic and robotic approaches, using open surgery as the reference. Models were adjusted for variables significantly associated with procedure type, including age, sex, income quartile, CCI score, and diagnosis of colon cancer. Analyses were stratified by rural and urban residence. Because multiple complication endpoints were analyzed, we acknowledge the increased risk of type I error. No formal correction for multiplicity was applied, and results should therefore be interpreted with caution, emphasizing effect sizes and clinical significance. Differences between rural and urban strata were considered potentially meaningful if the absolute difference in aORs was ≥10%.
Results
Background Characteristics by Procedure Type for Rural Residents
Bivariate Differences in Complication Rates by Procedure Type for Rural Residents
Adjusted Odds Ratios (aORs) for Complications Following Robotic and Laparoscopic Right Colectomies Compared to Open Procedures, Stratified by Rural and Urban Residence
1Analyses were adjusted for available background factors significantly associated with procedure type (age, gender, and income), the continuous Charlson Comorbidity Index, and diagnosis of colon cancer. Adjusted odds ratios (aORs) with 95% confidence intervals are reported. Results are presented separately for rural and urban patients. Differences between regions were considered potentially meaningful if the absolute difference in odds ratios was ≥10%. Parentheses represent the 95% confidence intervals.
2Laparoscopic approach.
Robotic surgery was more frequently performed among urban residents than rural residents (78.4% vs 71.7%; χ2(2) = 115.38, P < .001). While overall complication patterns were similar across geographic groups, certain outcomes showed greater benefit among urban residents. Applying an absolute difference threshold of ≥10% in aORs, urban residents experienced more favorable outcomes from robotic surgery for pneumonia and urinary tract infection, and from laparoscopic surgery for accidental puncture.
Discussion
Minimally invasive and open approaches to right colectomy have been widely studied in the surgical literature.2-4,8-15 However, few studies have stratified outcomes by geographic residence, limiting understanding of how these techniques perform in rural vs urban populations. As robotic platforms become increasingly available in non-metropolitan regions, examining patient-level outcomes by rurality is essential. 17
In the present study, rural patients who underwent open right colectomy experienced the highest rates of postoperative complications, while those who underwent minimally invasive procedures—particularly robotic—had significantly lower odds of complications. These findings are consistent with previous literature reporting improved outcomes for minimally invasive techniques, though prior studies have not typically examined rural subpopulations separately.2-4,8-15
When comparing laparoscopic and robotic procedures among rural residents, robotic colectomies were associated with the lowest odds of complications. This pattern aligns with some prior research suggesting a potential advantage of robotic approaches over laparoscopy, though other studies have reported comparable outcomes.8,9 The technical advantages of the da Vinci® system—such as enhanced ergonomics, tremor filtration, three-dimensional visualization, and increased instrument articulation—may contribute to these observed differences.6,7 In addition, expanding robotic training during surgical residency and fellowship may further optimize outcomes as experience accumulates.
Interestingly, urban residents undergoing robotic or laparoscopic colectomy appeared to experience even greater reductions in odds of complications than rural residents, particularly with respect to pneumonia, urinary tract infections, and accidental puncture. Several factors may contribute to these disparities, including differences in hospital infrastructure, surgical team experience, availability of specialized staff, and patient selection. The higher utilization of robotic surgery among urban residents in our data set may also reflect broader institutional adoption, surgeon familiarity, or differences in referral patterns.
These findings suggest potential disparities related to health care infrastructure, surgical expertise, and access to robotic platforms. However, because this analysis is observational and based on administrative data, outcomes can only be interpreted as associations. Robotic and laparoscopic approaches were associated with lower odds of complications compared with open surgery, but causality cannot be inferred.
As the adoption of robotic surgery continues to expand into rural communities, addressing barriers such as limited infrastructure and training capacity will be important. Still, our data do not establish that outcome differences are directly attributable to access alone, as institutional experience and patient mix likely contribute. Enhancing robotic surgery capacity and training in rural settings may be one potential strategy, but these findings should be considered hypothesis-generating rather than prescriptive.
This study has several strengths. It utilized a large, population-based data set with sufficient sample size to perform stratified analyses by rural and urban residence. It also adjusted for important covariates, including comorbidities, age, sex, and socioeconomic status and used a validated comorbidity index. The use of ZIP code-level residence data allowed for accurate classification of rurality based on standardized USDA criteria.
This study has several limitations. The administrative nature of the data set limits available clinical detail, including surgical complexity, operative time, or provider experience. Income was estimated at the ZIP code level and may not accurately reflect individual socioeconomic status. Additionally, the data set captures only inpatient events and does not include post-discharge complications or long-term outcomes. Finally, findings from Michigan may not be generalizable to rural populations in other states with differing health care infrastructure or population demographics.
Because multiple complication endpoints were analyzed, there is an increased risk of type I error. We did not apply a formal correction for multiple comparisons, and results should therefore be interpreted with caution, emphasizing effect sizes and clinical significance in addition to statistical significance. This analysis is also subject to coding bias inherent in administrative databases. ICD-10 procedure and diagnosis codes may be misclassified, underreported, or inconsistently applied across institutions, which may influence results.
Another limitation is the unusually high proportion of robotic colectomies (77%) observed in our data set compared with national estimates. Michigan has been identified as an early adopter of robotic surgery, with statewide use across general surgical procedures rising 8.4-fold between 2012 and 2018, and colectomy-specific robotic utilization increasing approximately 6.5-fold over the same period.17,22 This rapid regional uptake likely contributed to elevated robotic case proportions in our cohort but also raises the possibility of selection bias related to local practice patterns.
Finally, HCUP SID lacks surgeon- and hospital-level identifiers, which prevents adjustment for provider or institutional volume. Outcomes of minimally invasive and robotic procedures are strongly influenced by surgeon experience and hospital expertise. Therefore, rural-urban differences observed in this study may reflect institutional characteristics as much as patient-level access factors.
Conclusion
Minimally invasive right colectomy was associated with lower odds of complications compared to open procedures among Michigan residents, with robotic approaches showing the most favorable outcomes. Both rural and urban patients benefited, though urban residents appeared to experience greater reductions in odds for certain complications.
These findings suggest potential disparities that may be influenced by institutional experience, infrastructure, and access to robotic platforms. Given the limitations of administrative data and the observational design, results should be interpreted as associations rather than causation. Future studies incorporating hospital- and surgeon-level data, post-discharge outcomes, and institutional capacity are needed to clarify rural-urban differences and guide strategies to promote equitable access to advanced surgical care.
Footnotes
Author Note
Michigan HCUP NIS Approval #: HCUP Data Re-Use Request #28132.
Ethical Considerations
This study was approved for use of de-identified administrative data and did not involve direct human subjects research; therefore, institutional review board (IRB) approval and informed consent were not required.
Author Contributions
Ryan T. Davis, MD: Conceptualization, methodology, data interpretation, manuscript drafting, and overall project administration.
Ibrahim B. Baida, MD: Data acquisition, statistical interpretation, and manuscript revision.
Jacob A. Applegarth, MD: Data acquisition, statistical interpretation, and manuscript revision.
Beth A. Bailey, PhD: Data analysis, statistical modeling, and critical manuscript review.
Nathan M. Novotny, MD: Study supervision, clinical oversight, and final manuscript review.
Declaration of Conflicting Interest: The authors declare no potential conflicts of interest with respect to the research, authorship, or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data Availability Statement
The data used in this study are available through the Healthcare Cost and Utilization Project (HCUP) Michigan Inpatient Sample. Access may be granted upon request and approval through the Michigan Health and Hospital Association and HCUP Data Re-Use procedures.