Epidural Electrical Stimulation of the Lumbosacral Spinal Cord Improves Trunk Stability During Seated Reaching in Two Humans With Severe Thoracic Spinal Cord Injury

Synergistic implications of combinatorial rehabilitation approaches using spinal stimulation on therapeutic outcomes in spinal cord injury

OBJECTIVE

The objective of this narrative review was to locate and assess recent articles employing a combinatorial approach of transcutaneous spinal cord stimulation or epidural spinal cord stimulation with additional modalities. We sought to provide relevant knowledge of recent literature and advance understanding on outcomes reported, to better equip those working in neurorehabilitation and neuromodulation.

METHODS

Articles were selected and analyzed based on study approach, stimulation parameters, outcome measures, and presence of neurophysiological data to support findings.

RESULTS

This narrative review analyzed 44 recent articles employing a combinatorial approach of transcutaneous spinal cord stimulation or epidural spinal cord stimulation with additional modalities. Our findings showed that limited research exists regarding such combinatorial approaches, particularly when considering modalities beyond activity-based training. There is also limited consistency in neurophysiological and quality of life outcomes.

CONCLUSION

Articles involving transcutaneous spinal cord stimulation or epidural spinal cord stimulation with other modalities are limited in the current body of literature. Authors noted variety in approach, sample size, and use of participant perspective. Opportunities are present to add high quality research to this body of literature.

SIGNIFICANCE

Transcutaneous spinal cord stimulation and epidural spinal cord stimulation are emerging in research as viable avenues for targeting improvement of function after traumatic spinal cord injury, particularly when combined with activity-based training. This body of literature demonstrates viable areas for growth from both neurophysiological and functional perspectives. Further, exploration of novel combinatorial approaches holds potential to offer enhanced contributions to clinical and neurophysiological rehabilitation and research.

Functional outcomes and participants' perspectives during short-term application of spinal stimulation in individuals with spinal cord injury

OBJECTIVE

The primary objective of this study was to quantify changes in performance of task-specific motor activities over 12 motor rehabilitation sessions with lumbosacral spinal cord stimulation (SCS) via either transcutaneous stimulation or epidural stimulation. Both stimulation modalities have been used in recent years to restore functions lost to spinal cord injury (SCI). Secondary outcomes examine participants' perspectives captured via the User Experience Questionnaire (UEQ) upon study completion to further understand their perception of SCS.

METHODS

Six individuals with SCI completed 12 sessions with one modality of SCS during supine and/or side-lying, seated forward reaching, and standing activities. Changes in volitional lower extremity movement, the number of points of contact needed at hips and/or knees to facilitate standing, and changes in seated forward reaching distance were used to quantify performance. The UEQ was administered to gauge participants' perspectives following use of SCS to enable functions impaired due to SCI.

RESULTS

For all participants, performance of motor activities improved with SCS compared to without stimulation. Responses for the UEQ showed an overall positive perception of trialing SCS with rehabilitation to enhance motor functions impaired by SCI.

CONCLUSIONS

Regardless of injury severity, location of injury, time since SCI, or SCS modality, all participants experienced gains in motor function in the presence of SCS combined with a condensed rehabilitation program. However, no evidence of sustained motor functions was found in the absence of SCS. UEQ results highlight the positive perception of SCS with rehabilitation as well as the importance of consulting persons with lived experience of SCS during clinical trial design and protocol development.Trial registration: ClinicalTrials.gov identifier: NCT05095454.

Effects of Robotic Postural Stand Training with Epidural Stimulation on Sitting Postural Control in Individuals with Spinal Cord Injury: A Pilot Study

(1) Background. High-level spinal cord injury (SCI) disrupts trunk control, leading to an impaired performance of upright postural tasks in sitting and standing. We previously showed that a novel robotic postural stand training with spinal cord epidural stimulation targeted at facilitating standing (Stand-scES) largely improved standing trunk control in individuals with high-level motor complete SCI. Here, we aimed at assessing the effects of robotic postural stand training with Stand-scES on sitting postural control in the same population. (2) Methods. Individuals with cervical (n = 5) or high-thoracic (n = 1) motor complete SCI underwent approximately 80 sessions (1 h/day; 5 days/week) of robotic postural stand training with Stand-scES, which was performed with free hands (i.e., without using handlebars) and included periods of standing with steady trunk control, self-initiated trunk and arm movements, and trunk perturbations. Sitting postural control was assessed on a standard therapy mat, with and without scES targeted at facilitating sitting (Sit-scES), before and after robotic postural stand training. Independent sit time and trunk center of mass (CM) displacement were assessed during a 5 min time window to evaluate steady sitting control. Self-initiated antero-posterior and medial-lateral trunk movements were also attempted from a sitting position, with the goal of covering the largest distance in the respective cardinal directions. Finally, the four Neuromuscular Recovery Scale items focused on sitting trunk control (Sit, Sit-up, Trunk extension in sitting, Reverse sit-up) were assessed. (3) Results. In summary, neither statistically significant differences nor large Effect Size were promoted by robotic postural stand training for the sitting outcomes considered for analysis. (4) Conclusions. The findings of the present study, together with previous observations, may suggest that robotic postural stand training with Stand-scES promoted trunk motor learning that was posture- and/or task-specific and, by itself, was not sufficient to significantly impact sitting postural control.

Spinal Cord Epidural Stimulation Improves Lower Spine Sitting Posture Following Severe Cervical Spinal Cord Injury

Cervical spinal cord injury (SCI) leads to impaired trunk motor control, negatively impacting the performance of activities of daily living in the affected individuals. Improved trunk control with better sitting posture has been previously observed due to neuromuscular electrical stimulation and transcutaneous spinal stimulation, while improved postural stability has been observed with spinal cord epidural stimulation (scES). Hence, we studied how trunk-specific scES impacts sitting independence and posture. Fourteen individuals with chronic, severe cervical SCI with an implanted neurostimulator performed a 5-min tall-sit task without and with trunk-specific scES. Spine posture was assessed by placing markers on five spine levels and evaluating vertical spine inclination angles. Duration of trunk manual assistance was used to assess independence along with the number of independence changes and average independence score across those changes. With scES, the sacrum-L1 inclination and number of independence changes tended to decrease by 1.64 ± 3.16° (p = 0.07; Cohen's d = 0.53) and 9.86 ± 16.8 (p = 0.047; Cohen's d = 0.59), respectively. Additionally, for the participants who had poor sitting independence without scES, level of independence tended to increase by 12.91% [0%, 31.52%] (p = 0.38; Cohen's d = 0.96) when scES was present. Hence, trunk-specific scES promoted improvements in lower spine posture and lower levels of trunk assistance.

Multi-Site Spinal Cord Transcutaneous Stimulation Facilitates Upper Limb Sensory and Motor Recovery in Severe Cervical Spinal Cord Injury: A Case Study

Individuals with cervical spinal cord injury (SCI) rank regaining arm and hand function as their top rehabilitation priority post-injury. Cervical spinal cord transcutaneous stimulation (scTS) combined with activity-based recovery training (ABRT) is known to effectively facilitate upper extremity sensorimotor recovery in individuals with residual arm and hand function post SCI. However, scTS effectiveness in facilitating upper extremity recovery in individuals with severe SCI with minimal to no sensory and motor preservation below injury level remains largely unknown. We herein introduced a multimodal neuro-rehabilitative approach involving scTS targeting systematically identified various spinal segments combined with ABRT. We hypothesized that multi-site scTS combined with ABRT will effectively neuromodulate the spinal networks, resulting in improved integration of ascending and descending neural information required for sensory and motor recovery in individuals with severe cervical SCI. To test the hypothesis, a 53-year-old male (C2, AIS A, 8 years post-injury) received 60 ABRT sessions combined with continuous multi-site scTS. Post-training assessments revealed improved activation of previously paralyzed upper extremity muscles and sensory improvements over the dorsal and volar aspects of the hand. Most likely, altered spinal cord excitability and improved muscle activation and sensations resulted in observed sensorimotor recovery. However, despite promising neurophysiological evidence pertaining to motor re-activation, we did not observe visually appreciable functional recovery on obtained upper extremity motor assessments.

Neuromodulation for recovery of trunk and sitting functions following spinal cord injury: a comprehensive review of the literature

Trunk stability is crucial for people with trunk paralysis resulting from spinal cord injuries (SCI), as it plays a significant role in performing daily life activities and preventing from fall-related accidents. Traditional therapy used assistive methods or seating modifications to provide passive assistance while restricting their daily functionality. The recent emergence of neuromodulation techniques has been reported as an alternative therapy that could improve trunk and sitting functions following SCI. The aim of this review was to provide a broad perspective on the existing studies using neuromodulation techniques and identify their potentials in terms of trunk recovery for people with SCI. Five databases were searched (PubMed, Embase, Science Direct, Medline-Ovid, and Web of Science) from inception to December 31, 2022 to identify relevant studies. A total of 21 studies, involving 117 participants with SCI, were included in this review. According to these studies, neuromodulation significantly improved the reaching ability, restored trunk stability and seated posture, increased sitting balance, as well as elevated activity of trunk and back muscles, which were considered early predictors of trunk recovery after SCI. However, there is limited evidence regarding neuromodulation techniques on the improvement of trunk and sitting functions. Therefore, future large-scale randomized controlled trials are warranted to validate these preliminary findings.

Combined Transcutaneous Electrical Spinal Cord Stimulation and Task-Specific Rehabilitation Improves Trunk and Sitting Functions in People with Chronic Tetraplegia

The aim of this study was to examine the effects of transcutaneous electrical spinal cord stimulation (TSCS) and conventional task-specific rehabilitation (TSR) on trunk control and sitting stability in people with chronic tetraplegia secondary to a spinal cord injury (SCI). Five individuals with complete cervical (C4-C7) cord injury participated in 24-week therapy that combined TSCS and TSR in the first 12 weeks, followed by TSR alone for another 12 weeks. The TSCS was delivered simultaneously at T11 and L1 spinal levels, at a frequency ranging from 20-30 Hz with 0.1-1.0 ms. pulse width biphasically. Although the neurological prognosis did not manifest after either treatment, the results show that there were significant increases in forward reach distance (10.3 ± 4.5 cm), right lateral reach distance (3.7 ± 1.8 cm), and left lateral reach distance (3.0 ± 0.9 cm) after the combinational treatment (TSCS+TSR). The stimulation also significantly improved the participants' trunk control and function in sitting. Additionally, the trunk range of motion and the electromyographic response of the trunk muscles were significantly elevated after TSCS+TSR. The TSCS+TSR intervention improved independent trunk control with significantly increased static and dynamic sitting balance, which were maintained throughout the TSR period and the follow-up period, indicating long-term sustainable recovery.

Robust Control of the Human Trunk Posture Using Functional Neuromuscular Stimulation: A Simulation Study

The trunk movements of an individual paralyzed by spinal cord injury (SCI) can be restored by functional neuromuscular stimulation (FNS), which applies low-level current to the motor nerves to activate the paralyzed muscles to generate useful torques, to actuate the trunk. FNS can be modulated to vary the biotorques to drive the trunk to follow a user-defined reference motion and maintain it at a desired postural set-point. However, a stabilizing modulation policy (i.e., control law) is difficult to derive as the biomechanics of the spine and pelvis are complex and the neuromuscular dynamics are highly nonlinear, nonautonomous, and input redundant. Therefore, a control method that can stabilize it with FNS without knowing the accurate skeletal and neuromuscular dynamics is desired. To achieve this goal, we propose a control framework consisting of a robust control module that generates stabilizing torques while an artificial neural network-based mapping mechanism with an anatomy-based updating law ensures that the muscle-generated torques converge to the stabilizing values. For the robust control module, two sliding-mode robust controllers (i.e., a high compensation controller and an adaptive controller), were investigated. System stability of the proposed control method was rigorously analyzed based on the assumption that the skeletal dynamics can be approximated by Euler-Lagrange equations with bounded disturbances, which enables the generalization of the control framework. We present experiments in a simulation environment where an anatomically realistic three-dimensional musculoskeletal model of the human trunk moved in the anterior- posterior and medial-lateral directions while perturbations were applied. The satisfactory simulation results suggest the potential of this control technique for trunk tracking tasks in a typical clinical environment.

Single Lead Epidural Spinal Cord Stimulation Targeted Trunk Control and Standing in Complete Paraplegia

A 25-year-old male with T3 complete AIS A was implanted with percutaneous spinal cord epidural stimulation (scES; eight contacts each) leads and a Medtronic Prime advance internal pulse generator. The two leads were placed at the midline level to cover the region of the T11–T12 vertebrae. Five days after implantation, X-ray showed complete migration of the left lead outside the epidural space. Two weeks after implantation, reprogramming of the single right lead (20 Hz and 240 µs) after setting the cathode at 0 and the anode at 3 resulted in target activation of the abdominal muscles and allowed for the immediate restoration of trunk control during a seated position, even with upper extremity perturbation. This was followed by achieving immediate standing after setting the single lead at −3 for the cathode and +6 for the anode using stimulation configurations of 20 Hz and 240 µs. The results were confirmed with electromyography (EMG) of the rectus abdominus and lower extremity muscles. Targeted stimulation of the lumbosacral segment using a single lead with a midline approach immediately restored the trunk control and standing in a person with complete paraplegia.

Historical development and contemporary use of neuromodulation in human spinal cord injury

PURPOSE OF REVIEW

There is a long history of neuromodulation of the spinal cord after injury in humans with recent momentum of studies showing evidence for therapeutic potential. Nonrandomized, mechanistic, hypothesis-driven, small cohort, epidural stimulation proof of principle studies provide insight into the human spinal circuitry functionality and support the pathway toward clinical treatments.

RECENT FINDINGS

Individuals living with spinal cord injury can recover motor, cardiovascular, and bladder function even years after injury using neuromodulation. Integration of continuous feedback from sensory information, task-specific training, and optimized excitability state of human spinal circuitry are critical spinal mechanisms. Neuromodulation activates previously undetectable residual supraspinal pathways to allow intentional (voluntary) control of motor movements. Further discovery unveiled the human spinal circuitry integrated regulatory control of motor and autonomic systems indicating the realistic potential of neuromodulation to improve the capacity incrementally, but significantly for recovery after severe spinal cord injury.

SUMMARY

The discovery that both motor and autonomic function recovers with lumbosacral spinal cord placement of the electrode reveals exciting avenues for a synergistic overall improvement in function, health, and quality of life for those who have been living with the consequences of spinal cord injury even for decades.

Axon Regeneration: A Subcellular Extension in Multiple Dimensions

Axons are a unique cellular structure that allows for the communication between neurons. Axon damage compromises neuronal communications and often leads to functional deficits. Thus, developing strategies that promote effective axon regeneration for functional restoration is highly desirable. One fruitful approach is to dissect the regenerative mechanisms used by some types of neurons in both mammalian and nonmammalian systems that exhibit spontaneous regenerative capacity. Additionally, numerous efforts have been devoted to deciphering the barriers that prevent successful axon regeneration in the most regeneration-refractory system-the adult mammalian central nervous system. As a result, several regeneration-promoting strategies have been developed, but significant limitations remain. This review is aimed to summarize historic progression and current understanding of this exciting yet incomplete endeavor.

Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis

Epidural electrical stimulation (EES) targeting the dorsal roots of lumbosacral segments restores walking in people with spinal cord injury (SCI). However, EES is delivered with multielectrode paddle leads that were originally designed to target the dorsal column of the spinal cord. Here, we hypothesized that an arrangement of electrodes targeting the ensemble of dorsal roots involved in leg and trunk movements would result in superior efficacy, restoring more diverse motor activities after the most severe SCI. To test this hypothesis, we established a computational framework that informed the optimal arrangement of electrodes on a new paddle lead and guided its neurosurgical positioning. We also developed software supporting the rapid configuration of activity-specific stimulation programs that reproduced the natural activation of motor neurons underlying each activity. We tested these neurotechnologies in three individuals with complete sensorimotor paralysis as part of an ongoing clinical trial ( www.clinicaltrials.gov identifier NCT02936453). Within a single day, activity-specific stimulation programs enabled these three individuals to stand, walk, cycle, swim and control trunk movements. Neurorehabilitation mediated sufficient improvement to restore these activities in community settings, opening a realistic path to support everyday mobility with EES in people with SCI.

Invasive and Non-Invasive Approaches of Electrical Stimulation to Improve Physical Functioning after Spinal Cord Injury

This review of literature provides the latest evidence involving invasive and non-invasive uses of electrical stimulation therapies that assist in restoring functional abilities and the enhancement of quality of life in those with spinal cord injuries. The review includes neuromuscular electrical stimulation and functional electrical stimulation activities that promote improved body composition changes and increased muscular strength, which have been shown to improve abilities in activities of daily living. Recommendations for optimizing electrical stimulation parameters are also reported. Electrical stimulation is also used to enhance the skills of reaching, grasping, standing, and walking, among other activities of daily living. Additionally, we report on the use of invasive and non-invasive neuromodulation techniques targeting improved mobility, including standing, postural control, and assisted walking. We attempt to summarize the effects of epidural stimulation on cardiovascular performance and provide a mechanistic explanation to the current research findings. Future trends such as the combination of epidural stimulation and exoskeletal-assisted walking are also discussed.

Restoring Sensorimotor Function Through Neuromodulation After Spinal Cord Injury: Progress and Remaining Challenges

Spinal cord injury (SCI) is a major disability that results in motor and sensory impairment and extensive complications for the affected individuals which not only affect the quality of life of the patients but also result in a heavy burden for their families and the health care system. Although there are few clinically effective treatments for SCI, research over the past few decades has resulted in several novel treatment strategies which are related to neuromodulation. Neuromodulation-the use of neuromodulators, electrical stimulation or optogenetics to modulate neuronal activity-can substantially promote the recovery of sensorimotor function after SCI. Recent studies have shown that neuromodulation, in combination with other technologies, can allow paralyzed patients to carry out intentional, controlled movement, and promote sensory recovery. Although such treatments hold promise for completely overcoming SCI, the mechanisms by which neuromodulation has this effect have been difficult to determine. Here we review recent progress relative to electrical neuromodulation and optogenetics neuromodulation. We also examine potential mechanisms by which these methods may restore sensorimotor function. We then highlight the strengths of these approaches and remaining challenges with respect to its application.

Voluntary Modulation of Evoked Responses Generated by Epidural and Transcutaneous Spinal Stimulation in Humans with Spinal Cord Injury

Transcutaneous (TSS) and epidural spinal stimulation (ESS) are electrophysiological techniques that have been used to investigate the interactions between exogenous electrical stimuli and spinal sensorimotor networks that integrate descending motor signals with afferent inputs from the periphery during motor tasks such as standing and stepping. Recently, pilot-phase clinical trials using ESS and TSS have demonstrated restoration of motor functions that were previously lost due to spinal cord injury (SCI). However, the spinal network interactions that occur in response to TSS or ESS pulses with spared descending connections across the site of SCI have yet to be characterized. Therefore, we examined the effects of delivering TSS or ESS pulses to the lumbosacral spinal cord in nine individuals with chronic SCI. During low-frequency stimulation, participants were instructed to relax or attempt maximum voluntary contraction to perform full leg flexion while supine. We observed similar lower-extremity neuromusculature activation during TSS and ESS when performed in the same participants while instructed to relax. Interestingly, when participants were instructed to attempt lower-extremity muscle contractions, both TSS- and ESS-evoked motor responses were significantly inhibited across all muscles. Participants with clinically complete SCI tested with ESS and participants with clinically incomplete SCI tested with TSS demonstrated greater ability to modulate evoked responses than participants with motor complete SCI tested with TSS, although this was not statistically significant due to a low number of subjects in each subgroup. These results suggest that descending commands combined with spinal stimulation may increase activity of inhibitory interneuronal circuitry within spinal sensorimotor networks in individuals with SCI, which may be relevant in the context of regaining functional motor outcomes.

Recruitment order of motor neurons promoted by epidural stimulation in individuals with spinal cord injury

Spinal cord epidural stimulation (scES) combined with activity-based training can promote motor function recovery in individuals with motor complete spinal cord injury (SCI). The characteristics of motor neuron recruitment, which influence different aspects of motor control, are still unknown when motor function is promoted by scES. Here, we enrolled five individuals with chronic motor complete SCI implanted with a scES unit to study the recruitment order of motor neurons during standing enabled by scES. We recorded high-density electromyography (HD-EMG) signals on the vastus lateralis muscle, and inferred the order of recruitment of motor neurons from the relation between amplitude and conduction velocity of the scES-evoked EMG responses along the muscle fibers. Conduction velocity of scES-evoked responses was modulated over time, while stimulation parameters and standing condition remained constant, with average values ranging between 3.0±0.1 and 4.4±0.3 m/s. We found that the human spinal circuitry receiving epidural stimulation can promote both orderly (according to motor neuron size) and inverse trends of motor neuron recruitment, and that the engagement of spinal networks promoting rhythmic activity may favor orderly recruitment trends. Conversely, the different recruitment trends did not appear to be related with time since injury or scES implant, nor to the ability to achieve independent knees extension, nor to the conduction velocity values. The proposed approach can be implemented to investigate the effects of stimulation parameters and training-induced neural plasticity on the characteristics of motor neuron recruitment order, contributing to improve mechanistic understanding and effectiveness of epidural stimulation-promoted motor recovery after SCI.

Transcutaneous spinal cord stimulation improves postural stability in individuals with multiple sclerosis

BACKGROUND

Widespread demyelination in the central nervous system can lead to progressive sensorimotor impairments following multiple sclerosis, with compromised postural stability during standing being a common consequence. As such, clinical strategies are needed to improve postural stability following multiple sclerosis. The objective of this study was therefore to investigate the effect of non-invasive transcutaneous spinal stimulation on postural stability during upright standing in individuals with multiple sclerosis.

METHODS

Center of pressure displacement and electromyograms from the soleus and tibialis anterior were recorded in seven individuals with multiple sclerosis during standing without and with transcutaneous spinal stimulation. Center of pressure and muscle activity measures were calculated and compared between no stimulation and transcutaneous spinal stimulation conditions. The relationship between the center of pressure displacement and electromyograms was quantified using cross-correlation analysis.

RESULTS

For transcutaneous spinal stimulation, postural stability was significantly improved during standing with eyes closed: the time- and frequency-domain measures obtained from the anterior-posterior center of pressure fluctuation decreased and increased, respectively, and the tibialis anterior activity was lower compared to no stimulation. Conversely, no differences were found between no stimulation and transcutaneous spinal stimulation when standing with eyes open.

CONCLUSION

Following multiple sclerosis, transcutaneous spinal stimulation improved postural stability during standing with eyes closed, presumably by catalyzing proprioceptive function. Future work should confirm underlying mechanisms and explore the clinical value of transcutaneous spinal stimulation for individuals with multiple sclerosis.

The 2020 Yearbook of Neurorestoratology

COVID-19 has been an emerging and rapidly evolving risk to people of the world in 2020. Facing this dangerous situation, many colleagues in Neurorestoratology did their best to avoid infection if themselves and their patients, and continued their work in the research areas described in the 2020 Yearbook of Neurorestoratology. Neurorestorative achievements and progress during 2020 includes recent findings on the pathogenesis of neurological diseases, neurorestorative mechanisms and clinical therapeutic achievements. Therapeutic progress during this year included advances in cell therapies, neurostimulation/neuromodulation, brain-computer interface (BCI), and pharmaceutical neurorestorative therapies, which improved neurological functions and quality of life for patients. Four clinical guidelines or standards of Neurorestoratology were published in 2020. Milestone examples include: 1) a multicenter randomized, double-blind, placebo-controlled study of olfactory ensheathing cell treatment of chronic stroke showed functional improvements; 2) patients after transhumeral amputation experienced increased sensory acuity and had improved effectiveness in work and other activities of daily life using a prosthesis; 3) a patient with amyotrophic lateral sclerosis used a steady-state visual evoked potential (SSVEP)-based BCI to achieve accurate and speedy computer input; 4) a patient with complete chronic spinal cord injury recovered both motor function and touch sensation with a BCI and restored ability to detect objects by touch and several sensorimotor functions. We hope these achievements motivate and encourage other scientists and physicians to increase neurorestorative research and its therapeutic applications.

Clinical guidelines for neurorestorative therapies in spinal cord injury (2021 China version)

Treatment of spinal cord injury (SCI) remains challenging. Considering the rapid developments in neurorestorative therapies for SCI, we have revised and updated the Clinical Therapeutic Guidelines for Neurorestoration in Spinal Cord Injury (2016 Chinese version) of the Chinese Association of Neurorestoratology (Preparatory) and China Committee of International Association of Neurorestoratology. Treatment of SCI is a systematic multimodal process that aims to improve survival and restore neurological function. These guidelines cover real-world comprehensive neurorestorative management of acute, subacute, and chronic SCI and include assessment and diagnosis, pre-hospital first aid, treatment, rehabilitation, and complication management.