The association between paraplegia and adverse in-hospital outcomes after major cancer surgeries is virtually unknown. To address this knowledge gap, we relied on a large-scale population-based cohort within the NIS (2000–2019) testing the effect of paraplegia between paraplegic vs. non-paraplegic colectomy, radical hysterectomy, lung resection, gastrectomy and pancreatectomy patients. We made several noteworthy observations as follows.

First, the association between paraplegia and adverse in-hospital outcomes was never specifically and systematically addressed in large scale studies. In consequence, it was unknown to what extent paraplegic patients undergo major cancer surgeries. The current study demonstrated that a very small proportion of patients treated with major cancer surgeries are paraplegics. These rates ranged from 0.2 to 0.3% across the five examined major cancer surgery types. Despite the extremely large sample size available in the current database, the absolute numbers of paraplegic patients within one of the five major cancer surgery types, ranged from elevated at colectomy (n = 957) to relatively low at pancreatectomy (n = 75). These observations indicate the difficulty in systematic assessment of paraplegia effect on various endpoints in surgical patients.

Second, aside from paraplegia that distinguished the cases from non-paraplegic controls, we only identified one important difference in baseline characteristics between these two patient groups, namely CCI. Specifically, even after exclusion of paraplegia within CCI definition, these individuals harbored a higher count than their non-paraplegic counterparts. Interestingly, the magnitude of the difference in CCI was more pronounced at lung resection (42 vs. 29%, p < 0.001), followed by colectomy (52 vs. 43%, p < 0.001), radical hysterectomy (36 vs. 28%, p = 0.008) and gastrectomy (56 vs. 48%, p = 0.03). Additionally, no statistically significant difference in CCI count was identified at pancreatectomy (p = 0.7). Beside CCI, age at admission, sex and teaching hospital status exhibited statistically significant differences that may not be considered as clinically meaningful. However, their contribution requires consideration in statistical testing. In consequence, PSM was applied to maximally reduce or ideally eliminate the source of bias.

Third, after relying on PSM and multivariable adjustment within each of the five examined major cancer surgeries, paraplegia was invariably associated with higher rates of adverse in-hospital outcomes that ranged from twelve to as few as four examined categories. Similarly, the magnitude of the effect associated with paraplegia also ranged from 11-fold to only 1.3-fold increase. Most pronounced effect was recorded after colectomy and radical hysterectomy where paraplegia affected all twelve examined adverse in-hospital outcome categories. Conversely, increases in adverse in-hospital outcomes were respectively recorded in eleven, nine and four endpoints after lung resection, pancreatectomy and gastrectomy. These observations indicate that paraplegia exerts a specific effect on a distinguished number of adverse in-hospital outcomes and its magnitude is also specific for each of the examined major cancer surgery types. In consequence, major cancer surgery types-specific analyses are required. Moreover, a systematic approach such as the one used in the current study is clearly needed to address and quantify the association between paraplegia and adverse in-hospital outcomes according to specific adverse in-hospital outcomes definition.

Fourth, we also examined in-hospital mortality since it represents the most dire potential complication. Here, paraplegic patients invariably exhibited higher rates of in-hospital mortality than their non-paraplegic counterparts. Specifically, paraplegic patients exhibited higher rates of in-hospital mortality after pancreatectomy (16.0% vs. 3.3%; p < 0.001), lung resection (9.4% vs. 1.8%; p = 0.001), colectomy (10% vs. 3%; p < 0.001) and radical hysterectomy (< 4.4% vs. <0.4%; p < 0.001), but not after gastrectomy (p = 0.3). In multivariable analyses, presence of paraplegia independently predicted 3.8-, 5.8- and 6.3-fold higher rates of in-hospital mortality, for colectomy, lung resection and pancreatectomy, respectively. These observations are essential to communicate to paraplegic patients at clinical decision-making and informed consent.

Fifth, we also quantified the effect of paraplegia on length of stay ≥75th-percentile. Expectedly, a larger proportion of paraplegic patients required length of stay ≥75th-percentile. Interestingly, the magnitude of the increase was not related to the absolute length of stay ≥75th-percentile. After multivariable adjustment, the magnitude of the differences between length of stay ≥75th-percentile was greatest after lung resection (absolute: 7 days; OR 2.3), followed by pancreatectomy (absolute: 14 days; OR 2.1), colectomy (absolute: 11 days; OR 1.9), radical hysterectomy (absolute: 5 days; OR 1.8) and gastrectomy (absolute: 15 days; OR 1.5). In consequence, similarly to other examined endpoints, the effect of paraplegia differs according to major cancer surgery types when length of stay ≥75th-percentile represents the endpoints of interest.

Sixth, several mechanisms may explain the excess perioperative morbidity observed in paraplegic patients. Beyond the intrinsic autonomic, cardiovascular, and immune dysregulation associated with paraplegia [27,28,29], secondary factors such as neurogenic bladder and bowel dysfunction, reduced mobility, and impaired skin integrity contribute to urinary tract infections, ileus, and pressure ulcers—complications that may be partially preventable with specialized care [28,29,30,31]. In many general hospitals performing major cancer surgeries, expertise and resources specific to paraplegics’ management are limited. Inadequate bowel/bladder management, suboptimal positioning, and delayed mobilization may thus aggravate postoperative risk [30, 31]. Multidisciplinary co-management or early referral to specialized SCI centers—where structured nursing protocols and rehabilitation support are routine—could mitigate these risks [31, 32]. Where referral is not feasible, targeted education of surgical and nursing staff in bowel, bladder, and skin care protocols may represent a practical alternative. Future studies should examine whether such institutional factors modify perioperative outcomes in paraplegic surgical patients [33].

Taken together, the current observations indicate that paraplegic patients are invariably at higher risk of adverse in-hospital outcomes. The extent and the magnitude of the differences in adverse in-hospital outcomes, length of stay ≥75th-percentile and mortality rates are specific to each of the five examined major cancer surgeries.

The current study provides a first systematic assessment of the effect of paraplegia on 12 different adverse in-hospital outcomes and should ideally be used for medical decision-making at informed consent prior to one of the five examined major cancer surgeries. Despite the novelty of our observations, the present study is not devoid of limitations. First, the current results are only applicable to the five examined major cancer surgeries. They may not be extrapolated to other surgeries that may or may not be oncological. Second, selection and reporting biases may have remained due to the retrospective nature of the NIS. This limitation applies to the current study as well as to all previous analyses relying on the NIS [10,11,12,13,14,15,16,17] or other large-scale retrospective databases, such as the Surveillance Epidemiology and End Results database. Third, despite the very large size of the NIS, paraplegic patients were rare. Due to NIS reporting limitations, specific details could not be provided for some of the comparisons when patients count were less than 11. Instead, only relative metrics, such as OR, could be provided. Additionally, the amount of details included in the current analysis was also limited due to the nature of the NIS. For example, the specific etiology and clinical presentation of paraplegia and its duration, as well as the level of spinal cord injury were not available. Additionally, the NIS lacks relevant clinical data such as cancer stage, mean follow-up, neoadjuvant therapies, emergent versus elective status, and functional status. Furthermore, the small sample size for certain procedures (e.g., gastrectomy and pancreatectomy) precludes general causal conclusions. Moreover, despite the use of a standardized approach, a limited amount of details was available regarding the nature of the complications that were examined. For example, the amount of blood units used in transfusions was not known. Specifically, all of the complications examined within the current database were recorded retrospectively. Last but not least, the NIS exclusively provides in-hospital data. Therefore, it was not possible to assess further complications after the patient was discharged after major cancer surgery. Nevertheless, the present study provides the most detailed and methodologically structured analysis on the association between paraplegia and adverse in-hospital outcomes in paraplegic major cancer surgery patients.

Across the five major oncologic procedures, paraplegic patients consistently exhibited higher rates of adverse in-hospital outcomes. The excess risk was most pronounced after colectomy, radical hysterectomy, and lung resection, moderate after pancreatectomy, and least evident after gastrectomy. Similarly, the magnitude of the disadvantage also varied depending on the definition of adverse in-hospital outcome and major cancer surgery type.