Abstract
Objective:
To systematically determine whether usage of the spinal cord stimulation (SCS) system to restore cough may improve Bowel Management (BM) in individuals with SCI.
Design:
Experimental studies (Clinical trial).
Setting:
In-patient hospital setting for electrode insertion; out-patient setting for measurement of respiratory pressures; home setting for application of SCS.
Participants:
Participants (N = 5) with cervical spinal cord injury.
Intervention:
A fully implantable SCS cough system was surgically placed in each subject. SCS was applied at home, 2-3 times/day, on a chronic basis, every time bowel regimen was performed and as needed for secretion management. Stimulus parameters were set at values resulting in near maximum airway pressure generation (P), which was used as an index of expiratory muscle strength. Participants also employed SCS during their bowel routine.
Main Outcome Measure(s):
Airway pressure generation achieved with SCS. Weekly completion of Bowel Routine Log including BM time, mechanical measures and medications employed.
Results:
Mean P during spontaneous efforts was 30±8cmH2O. Following a period of reconditioning, SCS resulted in P of 146±21cmH2O. The time required for BM routines was reduced from 118±34 min to 18±2 min (p<0.05) and was directly related to the magnitude of P development during SCS. Mechanical methods for BM were completely eliminated in 4 patients. No patients experienced fecal incontinence as result of SCS. Each participant also reported marked overall improvement associated with BM.
Conclusions:
Our results of this pilot study suggest that SCS to restore cough may be a useful method to improve BM and life quality for both SCI patients and their caregivers. Our results indicate that the improvement in BM is secondary to restoration of intra-abdominal pressure development.
Keywords: Spinal Cord Injury, Tetraplegia, Bowel Management, Rehabilitation
Abnormalities in bowel function occur in a majority of individuals with spinal cord injury (SCI) and have a significant negative impact on their quality of life. In fact, surveys of SCI patients rate bowel dysfunction as a moderate to severe life-limiting problem, causing major restrictions on their social activities and quality of life.1–6 It is not surprising therefore that improving bowel function is rated as one of the highest priorities among these individuals.4,7,8,9
Upper motor neuron bowel syndrome or spastic bowel is defined by spinal cord lesions above the conus medullaris and is usually associated with constipation and fecal retention. Nervous connections between the spinal cord and colon are intact resulting in preserved reflex coordination and stool propulsion.10 Stool evacuation in these individuals usually occurs by means of reflex activity secondary to a stimulus introduced into the rectum, such as digital stimulation. The lower motor neuron bowel syndrome or flaccid bowel results from injury at the conus medullaris and cauda equina and is usually characterized by constipation but also a significant risk of incontinence.
Constipation in SCI occurs as a consequence of altered intestinal motility which leads to longer colonic transit times.10 As a result, one of the more important dysfunctions associated with BM is the excessive time required to complete routines. These sessions which are often required several times/week are estimated to last an average of 1.5-2.4 hours.11–13 In addition, other measures including suppositories, laxative, stool softeners and mechanical maneuvers are usually required, as well. It is likely therefore that any therapy with the potential to impact bowel regimen, would have a significant positive impact on life quality in individuals with SCI.
In our current clinical trial to restore an effective cough in individuals with cervical SCI, bi-polar spinal cord stimulation (SCS) is applied over the dorsal epidural surface at the T9 and T11 levels. SCS results in marked contraction of the expiratory muscles and the generation of large intra-abdominal and airway pressures resulting in the restoration of an effective cough.14,15–19 Although not systematically assessed, study participants often reported improvement in BM time as a beneficial side effect. Therefore, we modified our clinical protocol to prospectively investigate the impact of SCS on BM.
In a recent case report, we found that SCS has a significant beneficial clinical impact on BM including reductions in required medications and mechanical methods and marked reductions in the time required for BM routines.20 In the current investigation, we extend this initial finding by systematically and prospectively assessing the effects of SCS on BM in each of the last 5 subjects enrolled in our clinical trial to restore cough. The results of this pilot study demonstrate the SCS has a marked beneficial effect on BM with the additional finding that improvement in BM time is directly related to the magnitude of airway pressure development.
Methods
This interventional clinical trial (Clinical Trials Registry: NCT01659541) was approved by the Investigational Review Boards at MetroHealth Medical Center and the National Institute of Neurological Disorders and Stroke. All participants provided written informed consent prior to enrollment in the study.
Demographic and clinical information of each subject is provided in Table 1. All subjects were male. Cervical SCI resulted from trauma in 4 and an abscess in 1. Each subject had a motor complete cervical SCI (American Spinal Injury Association Impairment Scale A). Each subject was in stable medical condition at the time of study entrance. The time of injury was relatively recent in all, ranging between 2-4 years. No subjects had significant lung, cardiac or brain disease.
Table 1.
Clinical Data of the Participants
| Participant | Sex | Age (y) | Cause of Injury | Level of Injury | AIS | Elapsed Time Since Injury (y) | Spontaneous Inspiratory Capacity (L) (% predicted) |
Maximum Expiratory Pressure (cmH2O) (% predicted) |
|---|---|---|---|---|---|---|---|---|
| 1 | M | 50 | Equipment Accident | C4-C6 | A | 3 | 3.1 (92) | 59 (25) |
| 2 | M | 36 | Spinal Cord Abscess | C3-C6 | A | 3 | 1.4 (39) | 21 (9) |
| 3 | M | 35 | Fall | C6 | A | 4 | 2.5 (80) | 21 (9) |
| 4 | M | 30 | Diving Accident | C3 | A | 2 | 1.9 (61) | 33 (14) |
| 5 | M | 33 | MVA | C7/T1 | A | 2 | 1.0 (29) | 16 (7) |
| Mean | 37 | 3 | 2.0 (60) | 30 (14) |
Abbreviations: M, male; MVA, motor vehicle accident; AIS, American Spinal Cord Injury Impairment Scale
Placement and Use of the Electrical Stimulation System
Two wire leads, each with two electrode contactsa, were inserted percutaneously onto the dorsal epidural surface of the spinal cord via a needle placed in the upper lumbar region of the back.14,16 Under fluoroscopic guidance, each lead was advanced to the region of the upper T9 spinal level and placed in parallel. The fixed distance between the electrodes of each lead resulted in the lower electrodes being positioned near the T11 spinal level. Each lead was connected to a radiofrequency receiver (Finetech Medical Ltd, Welwyn Garden City, Herfordshire, United Kingdomb) which was implanted in a subcutaneous pocket over the anterior chest wall. Contraction of the expiratory muscles during SCS was verified intra-operatively both by visual observation and palpation of the abdominal muscles.
Following a 5-6 week recovery period, bi-polar electrical stimulation (T9-T11) was initiated by activating a small portable external transmitter connected to an antenna, which was secured to the skin with tape over the implanted receiver. The transmitter was activated by depressing a small button on the device. Due to disuse atrophy of the expiratory muscles, a period of repeated muscle stimulation over the course of several weeks was necessary to restore expiratory muscle strength. Following an initial evaluation, subjects applied SCS every 30 seconds for 5-10 minutes, 2-3 times/day in the home setting. For each individual, stimulus parameters were set at values resulting in maximal airway pressure generation. Subjects used the device 2-3 times/day, on a chronic basis to maintain expiratory muscle strength.21, 22 Subjects were also instructed to use the device for evacuation of secretions or airway clearance, as needed. Subjects also used their device during bowel routines at their discretion.
Vital signs were closely monitored following the initial application of SCS. If absolute systolic blood pressure exceeded 140 mmHg systolic or 90 mmHg diastolic, stimulation was held until values returned to baseline or less than 140 mmHg systolic or 90 mmHg diastolic. Increases in blood pressure was observed in 2 of the 5 individuals. However, with repeated use of SCS, blood pressure changes in association with SCS resolved completely over the course of several weeks with continued daily SCS.
Measurements
Each subject recorded the details of their BM for a 2-3-week period prior to implantation of the SCS stimulation system at weeks #1, 2, 3, 4, 8, 12, 17 and 21 following initiation of SCS (Table 2). Details of their BM routine including BM time, medications taken, employment of mechanical methods, frequency of bowel related activities and use of SCS were also recorded. Subjects also completed a weekly BM questionnaire rating the degree of change in their BM.
Table 2.
Medications and Methods Used to Facilitate Bowel Routine
| Participant | Pre-Implant | Week #1 | Week #2 | Week #3 | Week#4 | Week#8 | Week #12 | Week #17 | Week#21 |
|---|---|---|---|---|---|---|---|---|---|
| 1 | O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
O: Fiber,Colace (b.i.d) R: Enema (q.o.d), Suppositories |
| 2 | O: Senna (q.d) Colace (q.d) Milk of Magnesia (q.d) R: Suppositories (Dulcolax, Bisacodyl) Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Senna (q.d) Colace (q.d) Milk of Magnesia (q.d) R: Suppositories (Dulcolax, Bisacodyl) Mechanical Methods: Digital Evacuation |
O: Senna (q.d) Colace (q.d) Mirelax (q.d) R: Suppositories (Bisacodyl) Mechanical Methods: Digital Evacuation |
O: Senna (q.d) Colace (q.d) Mirelax (q.d) R: Suppositories (Bisacodyl) Mechanical Methods: Digital Evacuation |
O: Senna (q.d) Colace (q.d) Mirelax (q.d) R: Suppositories (Bisacodyl) Mechanical Methods: Digital Evacuation |
O: Senna (q.d) Colace (q.d) Mirelax (q.d) R: Suppositories (Bisacodyl) Mechanical Methods: Digital Evacuation |
O: Senna (q.d) Colace (q.d) Mirelax (q.d) R: Suppositories (Bisacodyl) Mechanical Methods: Digital Evacuation |
O: Senna (q.d) Colace (q.d) Mirelax (q.d) R: Suppositories (Bisacodyl) Mechanical Methods: Digital Evacuation |
O: Senna (q.d) Colace (q.d) Mirelax (q.d) R: Suppositories (Bisacodyl) Mechanical Methods: Digital Evacuation |
| 3 | O: Senna (q.i.d) Colace (b.i.d) R: Enema (q.o.d) Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Senna (q.i.d) Colace (b.i.d) R: Enema (q.o.d) Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Senna (q.i.d) Colace (b.i.d) R: Enema (q.o.d) Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Senna (q.i.d) Colace (b.i.d) R: Enema (q.o.d) Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Senna (q.i.d) Colace (b.i.d) R: Enema (q.o.d) Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Senna (q.i.d) Colace (b.i.d) R: Enema (q.o.d) Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Senna (q.i.d) Colace (b.i..d) R: Enema (q.o.d) |
O: Senna (q.i.d) Colace (b.i..d) R: Enema (q.o.d) |
O: Senna (q.d) Colace (q.d) R: Enema (q.o.d) |
| 4 | O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: Prune juice R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
| 5 | O: None R: None Mechanical Methods: Digital anorectal stimulation Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
O: None R: None Mechanical Methods: Digital Evacuation |
Participants returned to the out-patient clinic for follow-up measurements at week #0 (first day of stimulation), and at weeks #4, #8, #12, #17 and #21, following initiation of SCS. Airway pressure generation was assessed using a BIOPAC Data Acquisition and Analysis System with AcquKnowledge software, MP100 system with TSD 160 pressure transducer (Biopac Systems Inc., 42 Aero Camino, CA, USA).16 Measurements were made in the seated posture with use of a tight-fitting full face mask.
Measurements were made at functional residual capacity (FRC), total lung capacity (TLC) and at TLC with maximal subject expiratory effort.
Statistical Analyses
Data obtained prior to implantation were compared with data obtained after implantation of the cough system using a nonparametric analog (Freidman Test) to the standard repeated measures analysis of variance. Statistical significance was assumed at P<0.01. This alpha level was chosen as a correction for inflated type I error rates because of multiple comparisons. Results are reported as mean ± SE.
Results
Respiratory parameters of each of the study participants is provided in Table 1. Subjectively, each subject complained of difficulty generating an effective cough and mobilizing secretions. Objective evidence of significant paresis of their expiratory muscles was demonstrated by measurements of maximum expiratory pressure which was less than 30% predicted measured at TLC.
Consequent to muscle reconditioning, daily use of SCS resulted in the gradual increase in airway pressure generation over the course of the initial 4 to 17 weeks following which this parameter plateaued (Figure 1). Measured with 40V stimulation (50Hz, 0.2ms pulse width), airway pressure increased during SCS at FRC, TLC and TLC with maximum expiratory effort. As expected, pressure generation increased with increasing stimulus amplitude between 10 and 40V following the reconditioning period (Figure 2). For example, mean maximum airway pressure was 25±14, 52±24 and 77±21 cmH2O at 10V and 102±18, 132±23 and 144±20 cmH2O at 40V, when measured at FRC, TLC and TLC with maximal expiratory effort respectively. Each subject found 20-30V stimulation to be adequate for clearance of secretions and therefore used these voltages on a chronic basis.
Figure 1.
Mean airway pressures during SCS at FRC, TLC and at TLC with subject maximal expiratory effort. Mean spontaneous expiratory airway pressure is shown for comparison.
Figure 2.
Relationship between stimulus amplitude and mean airway pressures during SCS at FRC, TLC and at TLC with subject maximal expiratory effort. Mean spontaneous expiratory airway pressure is shown for comparison.
Subjects were not instructed to employ specific stimulation parameters for BM. Rather, each subject self-selected the number of stimulations applied, and voltages used for BM. The range of these parameters are summarized in Figure 3. Typically, 2-3 applications of SCS (20-30V, 50Hz, 0.2 pulse width) were applied every 2-7 min. and repeated several times.
Figure 3.
Typical pattern of SCS employed for BM. Subjects usually initiated their BM routine with oral and/or rectal medications. After a variable time period, they employed SCS (2-3 times) every 2-7 mins. Total time for BM ranged between 12 and 25 min.
The average frequency of BM activities for each study participant before and after initiation of SCS is provided in Table 3. Each subject engaged in their BM routine between 3 and 5 times/week. Prior to use of SCS, each subject employed mechanical methods including digital anorectal stimulation and digital evacuation. Three of the 5 subjects required medications including Colace and Senna. Two subjects required enemas and/or suppositories. One subject used only prune juice. Over the course of the subsequent 21 weeks of daily SCS, the use of mechanical methods became unnecessary in 2 subjects. The need for digital anorectal stimulation was eliminated in 2 of the 3 remaining subjects but each still employed digital evacuation. The use of medications for BM was reduced in 2 patients. Following SCS, each subject continued to employ their BM routine 3-5 times/week.
Table 3.
Average Frequency of Bowel Activities
| Participant | Pre-Implant | Week #1 | Week #2 | Week #3 | Week#4 | Week#8 | Week #12 | Week #17 | Week#21 |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 4/week | 4/week | 4/week | 4/week | 4/week | 4/week | 4/week | 4/week | 4/week |
| 2 | 4/week | 5/week | 5/week | 5/week | 5/week | 5/week | 5/week | 5/week | 5/week |
| 3 | 4/week | 4/week | 4/week | 4/week | 4/week | 4-5/week | 3/week | 3/week | 3/week |
| 4 | 7/week | 4/week | 4/week | 5/week | 4/week | 4/week | 4/week | 4/week | 4/week |
| 5 | 3/week | 3/week | 3/week | 3/week | 3/week | 3/week | 3/week | 3/week | 3/week |
The mean time required for BM during each session, for each subject is shown in minutes (Figure 4A) and as percent control (Figure 4B) over the course of the 21-week period of SCS. BM time decreased in each subject. Mean BM time fell from mean 118 ± 34 min pre-implant to 18 ± 2 min at week 21 (p<0.05). In percentage terms, BM time fell by 84 % at week #21. The largest changes however occurred by week #4 as the amount of time required for BM fell to 28.7% and 17.7% of control values by weeks #4 and 21, respectively.
Figure 4.
Amount of time in min (upper panel) and as a percent of control values (lower panel) required for bowel management over the course of the 21-week study period. period. There was a progressive reduction in the time required for bowel management after use of SCS. Most of the reductions in required time occurred within the first 4 weeks of the study period. See text for further explanation.
The gradual reduction in BM time was related to the increase in maximum airway pressure generation with SCS over the course of the reconditioning period. In Figure 5, airway pressure generation with 20V (left panel) and 30V (right panel) stimulation is plotted against BM time (R2=0.99 and R2=0.96, respectively). The flexibility of the polynomial regression technique allowed for the addition of a quadratic term, which keeps the models linear in the parameters. With 20V stimulation, there was a progressive decrease in BM time as airway pressure generation increased. This was most marked between 20 and 90 cmH2O. With 30V stimulation, BM time decreased until a plateaued was reached at ~110 and 130 cmH2O.
Figure 5.
Relationship between mean airway pressure generation during SCS with 20V (left hand panel) and 30V (right hand panel) and mean amount of time required for bowel management. The reduction in the amount of time required for BM was directly related to the degree of airway pressure generation. With 20V stimulation, there was a progressive reduction in BM time with increasing airway pressure generation. With 30V stimulation, there was also a progressive reduction in BM time with increasing pressure development which plateaued at ~120 cmH2O following which no further improvements were observed.
The subjective changes in BM on a 7-point scale ranging between markedly worse to marked improvement are shown in Figure 6. By week #3, each subject reported that SCS resulted in marked improvement in their BM routine. Moreover, this improvement persisted over the course of the 21-week study period.
Figure 6.
Mean subjective assessment of the degree of change in participants’ bowel management routine following use of SCS. There was marked improvement by week #1 and this degree of improvement persisted for the remainder of the 21-week study period.
Discussion
This is the first case series to demonstrate that activation of the expiratory muscles to restore cough via SCS has the beneficial side effect of improving BM in cervical SCI. While there was some reduction in required medications and need for mechanical methods for BM, the greatest benefit of SCS was a marked reduction in BM time. This represented an average reduction in time commitment from 118 min, 3-7 times/week or approx. 8.3 hours/week for both the study participant and caregiver to 18 min, 3-5 times/week or approx. 1.1 hours/week. Not surprisingly, these changes were associated with marked subjective improvement in these subjects’ BM. The significance of the findings of this report lie in the fact that individuals with SCI are more concerned with control of their intestinal function than with urinary control and body image.4
Interestingly, the pattern of usage of SCS for BM in this investigation (Figure 4) somewhat mimics recommended techniques for BM in that ano-rectal stimulation is typically followed by 5-10 minutes to assess effect, followed by repeat stimulation. If no stool if observed following repeated stimulation, the BM routine is completed.23
Study Limitations
This study encompasses only a small absolute number of SCI subjects. These results will need to be confirmed in a larger population sample. However, the fact that 5 consecutive individuals with cervical level of SCI each experienced a dramatic improvement in BM is highly significant and suggests that SCS has the potential to improve the lives of a substantial number of SCI patients.
Potential Mechanisms
The mechanism by which SCS improves BM is not clear. However, the results of this study demonstrate a significant relationship between the magnitude of airway pressure generation and BM time. This result suggests that the major impact of SCS on BM time is the development of large intra-abdominal pressures. This is not an entirely surprising finding since patients with cervical SCI have paralysis of virtually all of their expiratory muscles and therefore unable to generate the large intra-abdominal pressures typically employed during normal defecation. This mechanism has also been suggested by other investigators.24,25
Previous studies have shown that intra-abdominal pressures typically range between 135 and 270 cmH2O during normal defecatory maneuvers.26 Interestingly, the improvement in BM time plateaued with the development of airway pressures of ~120 cmH2 O, above which there were no further improvements. It should be noted that while intra-abdominal pressure was not measured in this study, it is likely that this pressure was somewhat higher than airway pressure and therefore in the range of that generated during normal defecation.
The ultimate consequences of increases in intra-abdominal pressure via SCS on colonic motility index, absolute transit times, peristalsis and autonomic function are beyond the scope of this study but merit further investigation.
Comparison to previous studies
Other electrical stimulation techniques have also been shown to improve BM in individuals with SCI. Sacral anterior root stimulation (S2-S4), which was placed to improve neurogenic bladder dysfunction,27,28 resulted in significantly less use of suppositories, digital stimulation and evacuation and enemas. Also, the proportion of subjects totally dependent on assistance during defecation was lower. In one study29 time for bowel evacuation was reduced from 26 to 12 min. This procedure also involves dissection of the sensory roots at these levels and for this reason is not appealing to many subjects with SCI. In another study involving persons who underwent SCS, employed with the intent to restore locomotor function, the time for defecation also decreased in 2 of 3 individuals. However, medication usage for BM and oral laxative usage was unchanged.25,30 Of note, this procedure required invasive laminotomy incisions for electrode placement. In a third study, surface stimulation of the abdominal wall using an abdominal belt with embedded electrodes in SCI individuals also resulted in a modest reduction in BM management time. Compared to these other stimulation methods, SCS compares very favorably in that there is marked improvement in BM including both significant reductions in BM time and reduction in usage of medications and mechanical methods. Moreover, the electrodes can be permanently placed, employing only minimally invasive techniques.
Clinical Implications
As mentioned, previous surveys of persons with SCI rate bowel dysfunction as a moderate to severe life-limiting problem, resulting in a major restriction on their social activities and quality of life.5,31,32 For this reason, some persons with SCI resort to colostomy placement to address this problem.10,33 This procedure however is not without its own complications and disadvantages including frequent colostomy bag replacement, costs of supplies, unpleasant odors, negative effects on body image and self-confidence and potential negative effects on sexual interactions. In individuals in whom constipation is the major complaint therefore, SCS appears to be a much more acceptable alternative to improving BM.
Lower thoracic SCS has now been shown to restore an effective cough, thereby reducing the incidence of respiratory tract infections, reduce the need for caregiver support and improve quality of life. In addition, this technique has been shown to improve pulmonary function and based upon some reports, restore the ability to sneeze, as well.14,17 Since SCS results in marked expiratory muscle contraction and the development of large airway pressures, it is not entirely surprising that SCS would improve other bodily functions which usually require forceful contraction of this muscle group such as defecation.
Side Effects/Complications
The most significant complication of lower thoracic SCS is the development of autonomic dysreflexia (AD) during the initial application of electrical stimulation in ~40-50% of study participants. We have observed signs of AD including increases in blood pressure and reductions in pulse but without the development of any symptoms. In the current study, this occurred in 2 of our 5 subjects but, as in our previous reports, the observed changes abated over several weeks of continued SCS.
Importantly, none of our study participants developed fecal incontinence secondary to SCS. This was not a surprising finding as none of the previous 24 study participants in our clinical trials to restore cough had developed this complication.
Conclusions
The results of this pilot study demonstrate that lower thoracic SCS employing wire lead electrodes which can be placed utilizing minimally invasive techniques results in substantial improvement in BM as reflected in marked reductions in BM time and reductions in use of medications and mechanical methods. The improvement in BM time is directly related to the increases in airway pressure associated with SCS. Lower thoracic SCS has the potential to represent the primary modality for BM in persons with cervical SCI and secondary constipation. This technique therefore merits further study including a larger population sample, effects of SCS on gut motility and colonic transit time and ultimately quality of life.
Acknowledgements
The valuable assistance of a statistician, Charles Thomas, BS is appreciated.
Funding: This work was supported by the National Institute of Neurological Disorders and Stroke [grant number U01 NS083696]. This project was supported by the Clinical and Translational Science Collaborative (CTSC) of Cleveland which is funded by the National institutes of Health (NIH), National Center for Advancing Translational Science (NCATS), Clinical and Translational Science Award (CTSA) grant, UL1TR002548.
This work was supported by the NIH-NINDS (U01 NS083696), CTSA (UL1TR0002548). This investigation was approved by the Institutional Review Board of MetroHealth Medical Center (IRB15-00014). Clinical Trials Registry: NCT01659541; FDA IDE: G980267. The valuable assistance of a statistician, Charles Thomas, BS is appreciated.
Footnotes
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Conflict of Interest Notification:
Conflicts of interest: Dr. DiMarco holds two United States Patents for technology related to the content of this paper: Method and Apparatus for Electrical Activation of the Expiratory Muscles to Restore Cough (5,999,855); Bipolar Spinal Cord Stimulation to Activate the Expiratory Muscles to Restore Cough (8,751,004).
ClinicalTrials.gov Identifier: NCT01659541
Suppliers
a. Ardiem Medical, Inc., Indiana, PA, USA
b. Finetech Medical Ltd., Welwyn Garden City, Herfordshire, UK
c. Biopac Systems Inc., 42 Aero Camino, CA, USA
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