Data-driven prediction of spinal cord injury recovery: An exploration of current status and future perspectives

Spinal Cord Injury (SCI) presents a significant challenge in rehabilitation medicine, with recovery outcomes varying widely among individuals. Machine learning (ML) is a promising approach to enhance the prediction of recovery trajectories, but its integration into clinical practice requires a thorough understanding of its efficacy and applicability. We systematically reviewed the current literature on data-driven models of SCI recovery prediction. The included studies were evaluated based on a range of criteria assessing the approach, implementation, input data preferences, and the clinical outcomes aimed to forecast. We observe a tendency to utilize routinely acquired data, such as International Standards for Neurological Classification of SCI (ISNCSCI), imaging, and demographics, for the prediction of functional outcomes derived from the Spinal Cord Independence Measure (SCIM) III and Functional Independence Measure (FIM) scores with a focus on motor ability. Although there has been an increasing interest in data-driven studies over time, traditional machine learning architectures, such as linear regression and tree-based approaches, remained the overwhelmingly popular choices for implementation. This implies ample opportunities for exploring architectures addressing the challenges of predicting SCI recovery, including techniques for learning from limited longitudinal data, improving generalizability, and enhancing reproducibility. We conclude with a perspective, highlighting possible future directions for data-driven SCI recovery prediction and drawing parallels to other application fields in terms of diverse data types (imaging, tabular, sequential, multimodal), data challenges (limited, missing, longitudinal data), and algorithmic needs (causal inference, robustness).

Long-term outcome and predictors of neurological recovery in cervical spinal cord injury: a population-based cohort study

This retrospective study analyzed prognostic factors for neurological improvement and ambulation in 194 adult patients (≥ 15 years) with traumatic cervical spinal cord injuries treated at the neurological SCI unit (SCIU) at the Karolinska University Hospital Stockholm, Sweden, between 2010 and 2020. The primary outcome was American spinal injury association impairment scale (AIS) improvement, with secondary focus on ambulation restoration. Results showed 41% experienced AIS improvement, with 51% regaining ambulation over a median follow-up of 3.7 years. Significant AIS improvement (p < 0.001) and reduced bladder/bowel dysfunction (p < 0.001) were noted. Multivariable analysis identified initial AIS C-D (< 0.001), central cord syndrome (p = 0.016), and C0-C3 injury (p = 0.017) as positive AIS improvement predictors, while lower extremity motor score (LEMS) (p < 0.001) and longer ICU stays (p < 0.001) were negative predictors. Patients with initial AIS C-D (p < 0.001) and higher LEMS (p < 0.001) were more likely to regain ambulation. Finally, older age was a negative prognostic factor (p = 0.003). In conclusion, initial injury severity significantly predicted neurological improvement and ambulation. Recovery was observed even in severe cases, emphasizing the importance of tailored rehabilitation for improved outcomes.

Rapid-Onset, Short-Duration Induction of Colorectal Contractions in Anesthetized, Adult, Male Rats

Substantial clinical and preclinical evidence indicates that transient receptor potential vanilloid 1 (TRPV1) receptors are expressed on terminals of colorectal chemoreceptors and mechanoreceptors and are involved in various rectal hypersensitivity disorders with common features of colorectal overactivity. These stimulatory properties of TRPV1 receptors on colorectal function suggested that brief stimulation of TRPV1 might provide a means of pharmacologically activating the colorectum to induce defecation in patients with an "unresponsive" colorectum. The current studies explored the basic features of TRPV1 receptor-induced contractions of the colorectum in anesthetized rats with and without acute spinal cord injury (aSCI). Cumulative concentration-response curves to intrarectal (IR) capsaicin (CAP) solutions (0.003%-3.0%) were performed in anesthetized aSCI and spinal intact rats. CAP produced an "inverted U," cumulative concentration-response curve with a threshold for inducing colorectal contractions at 0.01% and a peak response at 0.1% and slight decreases in responses up to 3%. Decreases in responses with concentrations >0.1% are due to a rapid desensitization (i.e., ≤30 minutes) of TRPV1 receptors to each successive dose. Desensitization appeared fully recovered within 24 hours in spinal intact rats. Colorectal contractions were completely blocked by atropine, indicating a reflexogenic activation of parasympathetic neurons, and responses were completely unaffected by a neurokinin 2 receptor antagonist, indicating that release of neurokinin A from afferent terminals and subsequent direct contractions of the smooth muscle was not involved. IR administration of three other TRPV1 receptor agonists produced similar results as CAP. SIGNIFICANCE STATEMENT: Individuals with spinal cord injury often lose control of defecation. Time-consuming bowel programs using digital stimulation of the rectum are used to empty the bowel. This study shows that intrarectal administration of the transient receptor potential vanilloid 1 (TRPV1) receptor agonist, capsaicin, can induce rapid-onset, short-duration colorectal contractions capable of inducing defecation in spinal cord injured and intact rats. Therefore, TRPV1 agonists show promise as potential therapeutics to induce defecation in individuals with neurogenic bowel.

Lesion characteristics are associated with bowel, bladder, and overall independence following cervical spinal cord injury

CONTEXT/OBJECTIVE

There is a growing global interest in quantifying spinal cord lesions and spared neural tissue using magnetic resonance imaging (MRI) in individuals with spinal cord injury (SCI). The primary objective of this study was to assess the relationships between spinal cord lesion characteristics assessed on MRI and bowel, bladder, and overall independence following SCI.

DESIGN

Retrospective, exploratory study.

PARTICIPANTS

93 individuals with cervical SCI who were enrolled in a local United States Model Systems SCI database from 2010 to 2017.

METHODS

Clinical and MRI data were obtained for potential participants, and MRIs of eligible participants were analyzed. Explanatory variables, captured on MRIs, included intramedullary lesion length (IMLL), midsagittal ventral tissue bridge width (VTBW), midsagittal dorsal tissue bridge width (DTBW), and axial damage ratio (ADR).

OUTCOME MEASURES

Bowel and bladder management scale of the Functional Independence Measure (FIM) and FIM total motor score.

RESULTS

When accounting for all four variables, only ADR was significantly associated with bowel independence (OR = 0.970, 95% CI: 0.942-0.997, P = 0.030), and both ADR and IMLL were strongly associated with bladder independence (OR = 0.967, 95% CI: 0.936-0.999, P = 0.046 and OR = 0.948, 95% CI: 0.919-0.978, P = 0.0007, respectively). 32% of the variation in overall independence scores were explained by all four predictive variables, but only ADR was significantly associated with overall independence after accounting for all other predictive variables (β = -0.469, 95% CI: -0.719, -0.218, P = 0.0004).

CONCLUSIONS

Our results suggest that the MRI-measured extent of spinal cord lesion may be predictive of bowel, bladder, and overall independence following cervical SCI.

Multivariable Prediction Models for Traumatic Spinal Cord Injury: A Systematic Review

Background

Traumatic spinal cord injuries (TSCI) greatly affect the lives of patients and their families. Prognostication may improve treatment strategies, health care resource allocation, and counseling. Multivariable clinical prediction models (CPMs) for prognosis are tools that can estimate an absolute risk or probability that an outcome will occur.

Objectives

We sought to systematically review the existing literature on CPMs for TSCI and critically examine the predictor selection methods used.

Methods

We searched MEDLINE, PubMed, Embase, Scopus, and IEEE for English peer-reviewed studies and relevant references that developed multivariable CPMs to prognosticate patient-centered outcomes in adults with TSCI. Using narrative synthesis, we summarized the characteristics of the included studies and their CPMs, focusing on the predictor selection process.

Results

We screened 663 titles and abstracts; of these, 21 full-text studies (2009-2020) consisting of 33 distinct CPMs were included. The data analysis domain was most commonly at a high risk of bias when assessed for methodological quality. Model presentation formats were inconsistently included with published CPMs; only two studies followed established guidelines for transparent reporting of multivariable prediction models. Authors frequently cited previous literature for their initial selection of predictors, and stepwise selection was the most frequent predictor selection method during modelling.

Conclusion

Prediction modelling studies for TSCI serve clinicians who counsel patients, researchers aiming to risk-stratify participants for clinical trials, and patients coping with their injury. Poor methodological rigor in data analysis, inconsistent transparent reporting, and a lack of model presentation formats are vital areas for improvement in TSCI CPM research.

Can the Initial Parameters of Functional Scales Predict Recovery in Patients with Complete Spinal Cord Injury? A Retrospective Cohort Study

Regaining greater independence in performing daily activities constitutes a priority for people with tetraplegia following spinal cord injury (SCI). The highest expectations are connected with the improvement of hand function. Therefore, it is so important for the clinician to identify reliable and commonly applicable prognostic factors for functional improvement. The aim of this study was to conduct an analysis to assess the impact of initial functional factors on the clinical improvement in patients during early neurological rehabilitation (ENR). This study assessed 38 patients with complete SCI aged 17-78 who underwent ENR in 2012-2022. The analysis included the motor score from the AIS (MS), the Barthel Index (BI) and the SCIM scale values at the beginning of the ENR program and after its completion. During ENR, patients achieved a statistically significant improvement in MS, BI and SCIM. The initial MS and the level of neurological injury constituted the predictors of functional improvement during ENR. Significant statistical relationships were observed primarily in the correlations between the initial MS and BI, and the increase in the analyzed functional scales of SCI patients. Higher initial MS may increase the chances of a greater and faster functional improvement during ENR.

Enabling knowledge translation: implementation of a web-based tool for independent walking prediction after traumatic spinal cord injury

Introduction

Several clinical prediction rules (CPRs) have been published, but few are easily accessible or convenient for clinicians to use in practice. We aimed to develop, implement, and describe the process of building a web-based CPR for predicting independent walking 1-year after a traumatic spinal cord injury (TSCI).

Methods

Using the published and validated CPR, a front-end web application called "Ambulation" was built using HyperText Markup Language (HTML), Cascading Style Sheets (CSS), and JavaScript. A survey was created using QualtricsXM Software to gather insights on the application's usability and user experience. Website activity was monitored using Google Analytics. Ambulation was developed with a core team of seven clinicians and researchers. To refine the app's content, website design, and utility, 20 professionals from different disciplines, including persons with lived experience, were consulted.

Results

After 11 revisions, Ambulation was uploaded onto a unique web domain and launched (www.ambulation.ca) as a pilot with 30 clinicians (surgeons, physiatrists, and physiotherapists). The website consists of five web pages: Home, Calculation, Team, Contact, and Privacy Policy. Responses from the user survey (n = 6) were positive and provided insight into the usability of the tool and its clinical utility (e.g., helpful in discharge planning and rehabilitation), and the overall face validity of the CPR. Since its public release on February 7, 2022, to February 28, 2023, Ambulation had 594 total users, 565 (95.1%) new users, 26 (4.4%) returning users, 363 (61.1%) engaged sessions (i.e., the number of sessions that lasted 10 seconds/longer, had one/more conversion events e.g., performing the calculation, or two/more page or screen views), and the majority of the users originating from the United States (39.9%) and Canada (38.2%).

Discussion

Ambulation is a CPR for predicting independent walking 1-year after TSCI and it can assist frontline clinicians with clinical decision-making (e.g., time to surgery or rehabilitation plan), patient education and goal setting soon after injury. This tool is an example of adapting a validated CPR for independent walking into an easily accessible and usable web-based tool for use in clinical practice. This study may help inform how other CPRs can be adopted into clinical practice.

Effective bowel management in spinal cord injury during inpatient rehabilitation: data from the Dutch spinal cord injury database

STUDY DESIGN

Retrospective Observational Study.

OBJECTIVES

To describe bowel management in individuals with a recently acquired spinal cord injury (SCI) both at admittance and discharge from first inpatient rehabilitation, and to determine factors that contribute to effective bowel management (EBM) at discharge.

SETTING

Specialized rehabilitation centers in the Netherlands.

METHODS

Data from the Dutch Spinal Cord Injury Database (DSCID) collected between 2015 and 2019 was used. EBM was defined by the variables of stool frequency and fecal incontinence. After univariate analysis, a multivariate regression analysis was conducted.

RESULTS

Of 1,210 participants, 818 (68%) did not have EBM at admittance. At discharge, 308 (38%) did still not have EBM (in total 33% of all participants). The odds of having EBM at discharge was 2.82 times higher for participants with ASIA Impairment Scale (AIS) D compared to those with AIS-A (95% CI: 1.38-5.78). Participants with non-traumatic SCI had higher odds of having EBM than those with traumatic SCI (OR: 0.59, 95% CI 0.38-0.91). Use of suppositories, small enema, medication influencing bowel function, and oral laxatives at admittance did not influence EBM significantly at discharge.

CONCLUSIONS

Bowel management improves during first inpatient rehabilitation. However, realizing EBM after a recently acquired SCI is a challenge. This endorses the importance of bowel management during inpatient rehabilitation, especially for people with AIS-A and non-traumatic etiology.

Prediction of Lower Urinary Tract, Sexual, and Bowel Function, and Autonomic Dysreflexia after Spinal Cord Injury

Spinal cord injury (SCI) produces damage to the somatic and autonomic pathways that regulate lower urinary tract, sexual, and bowel function, and increases the risk of autonomic dysreflexia. The recovery of these functions has a high impact on health, functioning, and quality of life and is set as the utmost priority by patients. The application of reliable models to predict lower urinary tract, sexual, and bowel function, and autonomic dysreflexia is important for guiding counseling, rehabilitation, and social reintegration. Moreover, a reliable prediction is essential for designing future clinical trials to optimize patients' allocation to different treatment groups. To date, reliable and simple algorithms are available to predict lower urinary tract and bowel outcomes after traumatic and ischemic SCI. Previous studies identified a few risk factors to develop autonomic dysreflexia, albeit a model for prediction still lacks. On the other hand, there is an urgent need for a model to predict the evolution of sexual function. The aim of this review is to examine the available knowledge and models for the prediction of lower urinary tract, sexual, and bowel function, and autonomic dysreflexia after SCI, and critically discuss the research priorities in these fields.

Prediction of bowel management independence after ischemic spinal cord injury

BACKGROUND

Ischemic spinal cord injury (SCI) belongs to the heterogeneous group of non-traumatic SCI, while the course of sensorimotor and functional recovery is comparable to traumatic SCI. Recently, we derived from data of patients with traumatic SCI a valid model to predict an independent and reliable bowel management one year after SCI.

AIM

To evaluate the performance of this model to predict an independent and reliable bowel management one year following ischemic SCI.

DESIGN

Prognostic study - observational study.

SETTING

European Multicenter Study about Spinal Cord Injury (EMSCI) ClinicalTrials.gov: NCT01571531.

POPULATION

One hundred and forty-two patients with ischemic SCI of various level and severity of injury.

METHODS

The prediction model relied on a single predictor collected within 40 days from injury, the International Standards for Neurological Classification of Spinal Cord Injury total motor score. Bowel outcome one year after SCI derived from the dichotomization of the Spinal Cord Independence Measure (SCIM) item 7 scores. We defined a positive outcome as independent bowel management with regular movements and appropriate timing with no or rare accidents (score of 10 in SCIM version II and score of 8 or 10 in version III).

RESULTS

The model showed a fair discrimination with an area under the receiver operating characteristic (ROC) curve of 0.780 (95% confidence interval=0.702-0.860). In addition, the model displayed an acceptable accuracy and calibration.

CONCLUSIONS

The study extends the validity of our rule to patients with ischemic SCI, thus providing the first model to predict an independent and reliable bowel management in this population.

CLINICAL REHABILITATION IMPACT

The model may be employed in clinical practice to counsel patients, to define the rehabilitation aims and to estimate the need of assistance after discharge, as well as in the research field for the optimization of patients' allocation in the design of future clinical trials.

Longitudinal Trends and Prevalence of Bowel Management in Individuals With Spinal Cord Injury

Background: Neurogenic bowel dysfunction (NBD) following spinal cord injury (SCI) represents a major source of morbidity, negatively impacting quality of life and overall independence. The long-term changes in bowel care needs are not well-reported, preventing consensus on the natural course and optimal management of NBD following injury. Objectives: To understand the changes in bowel management needs over time following SCI. Methods: A retrospective observational study using the National Spinal Cord Injury Model Systems database evaluated the degree of independence with bowel management at discharge from inpatient rehabilitation across time (1988-2016). The prevalence and consecutive trajectory of bowel management was also evaluated at discharge and at each 5-year follow-up period, for 25 years. Results: The majority of individuals discharged from inpatient rehabilitation (n = 17,492) required total assistance with bowel management, a trend that significantly increased over time. However, by 5-years post injury, there was a significant shift in bowel management needs from total assistance to modified independence. In those with consecutive 25-year follow-up data (n = 11,131), a similar shift in bowel management to a less dependent strategy occurred even at chronic time points post injury, primarily in individuals with paraplegia and classified as motor and sensory complete. Conclusion: The findings of this study highlight the need for providing continued multipronged interventions (e.g., rehabilitative, educational, psycho-social) at the different stages of SCI to support individuals not only in the immediate years after discharge but also well into the chronic stages after injury.

The potential of prediction models of functioning remains to be fully exploited: A scoping review in the field of spinal cord injury rehabilitation

OBJECTIVE

The study aimed to explore existing prediction models of functioning in spinal cord injury (SCI).

STUDY DESIGN AND SETTING

The databases PubMed, EBSCOhost CINAHL Complete, and IEEE Xplore were searched for relevant literature. The search strategy included published search filters for prediction model and impact studies, index terms and keywords for SCI, and relevant outcome measures able to assess functioning as reflected in the International Classification of Functioning, Disability and Health (ICF). The search was completed in October 2020.

RESULTS

We identified seven prediction model studies reporting twelve prediction models of functioning. The identified prediction models were mainly envisioned to be used for rehabilitation planning, however, also other possible applications were stated. The method predominantly used was regression analysis and the investigated predictors covered mainly the ICF components of body functions and activities and participation, next to characteristics of the health condition and health interventions.

CONCLUSION

Findings suggest that the development of prediction models of functioning for use in clinical practice remains to be fully exploited. By providing a comprehensive overview of what has been done, this review informs future research on prediction models of functioning in SCI and contributes to an efficient use of research evidence.

Who recovers independent bowel management during the first year following a traumatic spinal cord injury? A case-control study

OBJECTIVES

1) document the characteristics of patients with impaired bowel functioning during the subacute and chronic phases; 2) identify factors associated with recovery of independent bowel functioning during the first year following TSCI in patients who present impaired bowel functioning during the subacute phase, when bowel rehabilitation is completed.

DESIGN

Case-control study on 123 adult TSCI patients. Bowel function assessments using item 7 of the SCIM-III were obtained 3-months following TSCI and during the early chronic phase. Univariate and multivariate analyses were conducted to identify predictors associated with recovery of independent bowel functioning between the initial assessment and follow-up.

RESULTS

Of the 110 patients available for analysis, 54 (49%) displayed impaired bowel functioning 3-months following TSCI. Of these, 19 (35%) recovered independent bowel functioning over the following 9 months. The total motor score (TMS) was the only significant predictor of this outcome. A TMS lower than 42 was 100% predictive of absence of recovery.

CONCLUSION

Recovering independent bowel management 1-year after TSCI was possible in 35% of patients despite impaired bowel functioning during the subacute phase. TMS measured 3-months post-injury could be useful for prognosticating potential for bowel functioning recovery since patients with TMS < 42 are unlikely to recover.

Reliability and validity of the international standards for neurological classification of spinal cord injury in patients with non-traumatic spinal cord lesions

STUDY DESIGN

Prospective, observational study.

OBJECTIVES

The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) represent the gold standard for the assessment of patients with spinal cord injury (SCI) and their measurement properties have been evaluated in patients with traumatic lesions. Albeit the ISNCSCI are widely used also for the assessment and prognosis of patients with non-traumatic SCI, a validation of this grading system in this sample has never been performed. Therefore, the aim of this study is to evaluate the measurement properties of the ISNCSCI in a population of persons with non-traumatic SCI.

SETTING

Three Italian rehabilitation hospitals.

METHODS

The sample included 140 patients with non-traumatic SCI of different etiology, level and grade, for a total of 169 evaluations performed by two examiners. Cronbach's Alpha was used to evaluate the internal consistency of the ISNCSCI various components. The agreement between two examiners of each center in the definition of different components was used to assess the inter-rater reliability. The construct validity was evaluated through the correlation of the ISNCSCI with the Spinal Cord Independence Measure (SCIM).

RESULTS

The ISNCSCI showed substantial internal consistency, and substantial inter-rater agreement for AIS grade, cumulative motor and sensory scores. The motor scores for upper and lower extremity showed fair to moderate correlation with SCIM self-care and motility subscores, respectively. The ISNCSCI total motor score correlated with the total SCIM score.

CONCLUSIONS

Our study demonstrates that the ISNCSCI are a valid and reliable tool for the assessment of patients with non-traumatic SCI.

External Validation Confirms Validity of a Simple Model to Predict Bowel Outcome After Traumatic Spinal Cord Injury

Background. The prediction of functional outcomes after spinal cord injury (SCI) is essential to plan the rehabilitation phase and the social reintegration. Recently, 2 models to predict independent and reliable bowel management 1 year after traumatic SCI have been derived and validated in 2 cohorts of patients included in the European Multicenter Study about Spinal Cord Injury (EMSCI). Objective. We aimed to validate 2 prediction models for bowel outcome after traumatic SCI in a patient sample external to EMSCI. Methods. The simplified model (based on a single predictor, the International Standards for Neurological Classification of Spinal Cord Injury [ISNCSCI] total motor score) and the full model (based on 2 predictors, the ISNCSCI total motor score and item 3a of the Spinal Cord Independence Measure) were applied to the retrospectively collected data of 111 patients with traumatic SCI. Results. The simplified and the full models showed excellent discrimination with an area under the receiver operating characteristic curve of .939 (95% confidence interval (CI) .87-1.00) and .922 (95% CI 0.85-.99), respectively. Both models displayed similar results for sensitivity and negative predictive values; however, the simplified model showed higher values for specificity, positive predictive values, and accuracy. The calibration analysis showed a partial overlap between predicted probabilities and observed proportion, with better and acceptable calibration for the simplified model. Conclusions. Using an independent sample, our study demonstrates the validity of a simple model to predict independent and reliable bowel management 1 year after traumatic SCI.

Neurogenic Bowel in Acute Rehabilitation Following Spinal Cord Injury: Impact of Laxatives and Opioids

Objective: To explore the association between bowel dysfunction and use of laxatives and opioids in an acute rehabilitation setting following spinal cord injury (SCI). Methods: Data was collected regarding individuals with acute traumatic/non-traumatic SCI over a two-year period (2012–2013) during both the week of admission and discharge of their inpatient stay. Results: An increase in frequency of bowel movement (BM) (p = 0.003) and a decrease in frequency of fecal incontinence (FI) per week (p < 0.001) between admission and discharge was found across all participants. There was a reduction in the number of individuals using laxatives (p = 0.004) as well as the number of unique laxatives taken (p < 0.001) between admission and discharge in our cohort. The number of individuals using opioids and the average dose of opioids in morphine milligram equivalents (MME) from admission to discharge were significantly reduced (p = 0.001 and p = 0.02, respectively). There was a positive correlation between the number of laxatives and frequency of FI at discharge (r = 0.194, p = 0.014), suggesting that an increase in laxative use results in an increased frequency of FI. Finally, there was a significant negative correlation between average dose of opioids (MME) and frequency of BM at discharge, confirming the constipating effect of opioids (r = −0.20, p = 0.009).

Prediction of independence in bowel function after spinal cord injury: validation of a logistic regression model

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVES

Recently, logistic regression models were developed to predict independence in bowel function 1 year after spinal cord injury (SCI) on a multicenter European SCI (EMSCI) dataset. Here, we evaluated the external validity of these models against a prospectively accrued North American SCI dataset.

SETTING

Twenty-five SCI centers in the United States and Canada.

METHODS

Two logistic regression models developed by the EMSCI group were applied to data for 277 patients derived from three prospective multicenter SCI studies based in North America. External validation was evaluated for both models by assessing their discrimination, calibration, and clinical utility. Discrimination and calibration were assessed using ROC curves and calibration curves, respectively, while clinical utility was assessed using decision curve analysis.

RESULTS

The simplified logistic regression model, which used baseline total motor score as the predictor, demonstrated the best performance, with an area under the ROC curve of 0.869 (95% confidence interval: 0.826-0.911), a sensitivity of 75.5%, and a specificity of 88.5%. Moreover, the model was well calibrated across the full range of observed probabilities and displayed superior clinical benefit on the decision curve.

CONCLUSIONS

A logistic regression model using baseline total motor score as a predictor of independent bowel function 1 year after SCI was successfully validated against an external dataset. These findings provide evidence supporting the use of this model to enhance the care for individuals with SCI.