Pressure changes under the ischial tuberosities of seated individuals during sacral nerve root stimulation

Neuromuscular stimulation via the sacral nerve roots is proposed for prevention of ischial pressure ulcers following a spinal cord injury (SCI). Acute effects of sacral functional magnetic stimulation (FMS) on seat interface pressure changes were investigated in five nondisabled volunteers. Similar effects were demonstrated with functional electrical stimulation in people with SCI who used a sacral anterior root stimulator implant. The results indicated that sacral nerve root stimulation, either by FMS or implanted electrical stimulation, induced gluteus maximus contraction and mild pelvic tilt sufficient for clinically significant reductions in ischial pressures during sitting.     

Blood perfusion changes during sacral nerve root stimulation versus surface gluteus electrical stimulation on in seated spinal cord injury

The objective of this article is to examine dynamic changes of ischial blood perfusion during sacral nerve root stimulation against surface functional electrical stimulation (FES). Fourteen adults with suprasacral spinal cord injury (SCI) were recruited. The gluteal maximus was activated by surface FES or stimulating sacral nerve roots by functional magnetic stimulation (FMS) or a sacral anterior root stimulator implant (SARS). Ischial skin index of hemoglobin (IHB) and oxygenation (IOX) was measured.Skin blood perfusion was significantly higher during FMS than the baseline (IHB 1.05 ± 0.21 before vs.1.08 ± 0.02 during stimulation, p = 0.03; IOX 0.18 ± 0.21 before vs. 0.46 ± 0.30, p = 0.01 during stimulation). Similarly, when using the SARS implant, we also observed blood perfusion significantly increased (IHB 1.01 ± 0.02 before vs.1.07 ± 0.02 during stimulation, p = 0.003; IOX 0.79 ± 0.81 before vs. 2.2 ± 1.21 during stimulation, p = 0.036). Among four participants who completed both the FMS and FES studies, the magnitude of increase in both parameters was significantly higher during FMS. This study demonstrates sacral nerve root stimulation confer better benefit on blood perfusion than applying traditional FES in SCI population.     

The use of sensory electrical stimulation for pressure ulcer prevention

Pressure ulcer prevention is critically important for many people with reduced mobility. The authors investigated whether sensory (sub-motor-threshold) electrical stimulation (ES) may provide a convenient preventive intervention. A double-blinded, repeated measures study design was used to test the hypothesis that repeated use of sensory surface ES improves tissue health status in individuals with motor paralysis. Six adult males with complete spinal cord injury (SCI) were randomly assigned to treatment or control groups. The treatment group received the ES intervention, whereas the control group received a control sham intervention. Repeated tissue health assessments included transcutaneous oxygen tension (T_cPO₂), interface pressure mapping, and gluteal computed tomography (CT) studies. An initial increase in T_cPO₂ following use of subthreshold ES was observed but was not sustained at follow-up. No statistically significant changes before and after treatment were found in regional T_cPO₂, gluteal muscle area or pressure distribution. Thus subthreshold ES does not appear to have any sustained effects on tissue health status indicative of reduced pressure ulcer risk for individuals with SCI. This implies that a contractile muscle response is critically important and further that subthreshold ES is unlikely to prevent pressure ulcers. Further studies are needed to find solutions for preventing pressure ulcers in high-risk populations.     

Effects of regular use of neuromuscular electrical stimulation on tissue health

Changes in tissue health were monitored in a group of spinal cord injury (SCI) individuals with the use of an implanted neuromuscular electrical stimulation (NMES) system to provide standing and to facilitate standing transfers. Tissue health was evaluated through monitoring tissue oxygen levels in the ischial region along with measuring interface pressures at the seating support interface. Baseline assessments were done at study enrollment and repeated on completion of a conditioning exercise program. Serial assessments of tissue health were performed on eight NMES implant recipients. Unloaded tissue oxygen levels in the ischial region tended to increase after following the NMES exercise program for 8 weeks. Concurrently, pressure distributions at the seating support interface tended to change such that although the total pressure acting at the interface did not change, ischial region pressures showed a significant decrease. These changes indicate that chronic use of NMES has a quantifiable benefit on tissue health.     

骶神经根电刺激对鼠神经原性膀胱储尿功能的影响

背景神经原性膀胱最为典型也最有临床意义的表现为患者的储尿功能障碍,其发生大多直接或间接与骶神经根功能的失调有关,因而骶神经根埋植式电刺激被认为是一种可能的较好的治疗手段,可通过对骶髓排尿及控尿中枢的调节而改善储/排尿.目的探讨骶神经根埋植式电刺激对大鼠神经原性膀胱储尿功能的影响.设计完全随机的对照实验研究.地点和材料 Wistar雌性大鼠 20只,体重 180～ 220 g,由第三军医大学动物实验中心提供.制作神经原性大鼠膀胱模型,并将其随机分为刺激组及对照组.干预 刺激组予埋植式骶神经根电刺激治疗,对照组予假手术.主要观察指标 电刺激 1月后观察尿动力学改变及 Caspase3mRNA表达的变化.结果 电刺激 1月后膀胱储尿能力明显加强,膀胱容量增加 (0.095± 0.083) mL,顺应性显著升高 (t=-3.92,P< 0.05), Caspase3mRNA表达较对照组显著降低 (0.58± 0.44).结论 骶神经根电刺激可显著改善神经原性膀胱的储尿能力,并能延缓逼尿肌细胞的凋亡,保存逼尿肌功能.     

Design of the advanced commode-shower chair for spinal cord-injured individuals

The purpose of this development project was to design a new commode-shower chair that can be safely used by individuals with spinal cord injuries (SCI) and their caregivers. The need for this new design was consumer-driven. Patients and caregivers identified the following fatal flaws in the commode-shower chairs used in Spinal Cord Injury (SCI) centers: 1) risk for patient falls during transfers, propelling, and while leaning over for showering; 2) risk for pressure ulcers due to inadequate padding and seat positioning for lengthy bowel care regimes; 3) inadequate caregiver access to the perianal area of the patient to perform bowel care procedures; and, 4) wheel-related inability to properly position the chair directly over the toilet. The new, self-propelled chair addresses each of these concerns. Lockable, swing-away, pivoting armrests and improved, lever-activated brakes were designed to facilitate safe transfers. An innovative foot-lift was invented to facilitate washing of feet. Larger handrims were designed to aid in propulsion in wet environments. To prevent pressure ulcers, a chair frame and padding combination was designed to facilitate a seating position that optimally distributes body weight to prevent the development of pressure ulcers in the sacral and ischial areas. To address the common risk of heel ulcers, footrests, featuring edgeless, rounded heel cups, were designed. A new tubular chair frame, a new seat and smaller wheels were designed to enhance caregiver access and ensure proper chair positioning over the toilet. Following its successful clinical evaluation at the Milwaukee and Tampa VA Medical SCI Centers, the Advanced commode-shower chair is being patented by the Department of Veterans Affairs (VA). The VA has partnered with Everest & Jennings, to make this chair available commercially.     

The effect of surface electric stimulation of the gluteal muscles on the interface pressure in seated people with spinal cord injury

van Londen A, Herwegh M, van der Zee CH, Daffertshofer A, Smit CA, Niezen A, Janssen TW. The effect of surface electric stimulation of the gluteal muscles on the interface pressure in seated people with spinal cord injury.

Objective

To study effects of surface electric stimulation of the gluteal muscles on the interface pressure in seated persons with spinal cord injury (SCI).

Design

One session in which alternating and simultaneous surface electric stimulation protocols were applied in random order.

Setting

Research laboratory of a rehabilitation center.

Participants

Thirteen subjects with SCI.

Intervention

Surface electric stimulation of the gluteal muscles.

Main Outcome Measures

Interface pressure, maximum pressure, pressure spread, and pressure gradient for the stimulation measurement. Variables were compared using 2-tailed paired t tests.

Results

Alternating and simultaneous stimulation protocol caused a significant (P<.01) decrease in interface pressure (-17±12mmHg, -19±14mmHg) and pressure gradient (-12±11mmHg, -14±12mmHg) during stimulation periods compared with rest periods. There was no significant difference in effects between the 2 protocols.

Conclusions

Surface electric stimulation of the gluteal muscles in persons with SCI causes a decrease in interface pressure. This might restore blood flow in compressed tissue and help prevent pressure ulcers.     

不同频率功能性磁刺激对脊髓损伤后尿潴留患者排尿功能的影响

目的:观察不同频率功能性磁刺激(FMS)作用于骶3(S3)神经根对脊髓损伤后尿潴留患者排尿功能恢复的影响。方法:纳入45例脊髓损伤后神经源性膀胱的患者,根据患者选择治疗方法的不同,按随机数字表法分为5 Hz组(采用5 Hz频率FMS治疗)、20 Hz组(采用20 Hz频率FMS治疗)和假刺激组(采用与5 Hz组同参数同...     

What Lies Beneath: Why Some Pressure Injuries May Be Unpreventable for Individuals With Spinal Cord Injury

ObjectiveTo investigate intersections between pressure injury (PrI) history, muscle composition, and tissue health responses under physiologically relevant loading conditions for individuals with spinal cord injury (SCI).DesignRepeated measures study design with annual follow-up for up to 3 years.SettingTertiary care center.ParticipantsPersons with SCI (N=38). Exclusion criteria included having an open pelvic region PrI at the time of recruitment, presence of systemic disease, and/or known sensitivity to contrast.InterventionsNot applicable.Main Outcome MeasuresGluteal muscle composition, ischial interface pressures, tissue oxygenation.ResultsIschial region mean interface pressures are the same for individuals with or without a PrI history. Tissue oxygenation is lower during sitting for persons with a PrI history. Individuals with >15% gluteal intramuscular fat were statistically highly significantly (P<.001) more likely to have a history of severe or recurrent PrI. Intramuscular adipose tissue (IMAT) levels within the gluteal muscle may remain low over time or muscle tissue in the gluteal muscle region may be almost entirely replaced by IMAT. In the current study cohort, it was found that muscle composition also continues to change over time even for individuals with long-standing SCI.ConclusionsSoft-tissue compositional changes, specifically IMAT, provides a reliable indicator of PrI history and may provide a key to personalized PrI risk status for persons with SCI. The current findings confirm that interface pressure mapping alone is a limited indicator for PrI development.     

Comparison of direct bladder and sacral nerve stimulation in spinal cats.

Neuroprosthetic techniques have been used to facilitate voiding via electrical stimulation for bladder management following spinal cord injury (SCI), but high urethral resistance has been a problem. This problem was investigated here in the chronic, spinal, male cat (C6-T1) using direct bladder and sacral nerve stimulation. Direct bladder stimulation was only conducted during terminal procedures with an open abdomen and with four hook electrodes inserted into the bladder wall. Sacral stimulation was conducted daily during the 10 weeks post-SCI and during terminal procedures. Stimulation was conducted with both implanted epidural electrode and surface electrodes over the sacral bone. Both of these sacral methods stimulated anterior and posterior roots. However, these sacral methods were generally ineffective for inducing voiding during the study. In three of the five animals investigated, stimulation did not empty the bladder. In the remaining two animals, the bladder was emptied with sacral stimulation, but only after return of bladder reflex activity, 2 to 4 weeks post-injury. When poor voiding occurred in spite of high bladder pressures, it indicates high urethral resistance. This was confirmed using video cystourethrography where the membranous urethra was observed to remain closed following stimulation. Direct bladder stimulation was then compared to sacral nerve stimulation during terminal procedures. Direct bladder stimulation induced voiding at a high rate both during and after stimulation, whereas sacral nerve stimulation with implanted electrodes induced voiding at a lower rate and only after stimulation. A simple urethral resistance measure, the ratio of bladder pressure to voiding rate, was lower with direct bladder stimulation than sacral nerve stimulation. Stimulation-facilitated voiding has also been associated with the development of bladder wall hypertrophy. This problem was investigated by evaluating bladder wall thickness postmortem in three groups of animals: the first group was the spinal-stimulated animals detailed above; the additional two groups were a spinal-nonstimulated but instrumented group maintained for 10 weeks following injury, and an intact group of animals. The stimulated spinal cats tended to have the thickest bladder wall followed by the nonstimulated spinal cats. The wall thickness of intact animals served as a control.     

Functional magnetic stimulation of the colon in persons with spinal cord injury

OBJECTIVE: To evaluate the usefulness of functional magnetic stimulation (FMS) as a noninvasive method to stimulate the colon in individuals with spinal cord injury (SCI). DESIGN: A prospective before-after trial consisting of 2 protocols. SETTING: FMS laboratories of 2 SCI centers. PARTICIPANTS: Two able-bodied men and 13 men with SCI levels ranging from C3 to L1. Protocol 1 consisted of 9 subjects, 2 of whom were excluded from the analysis. Protocol 2 consisted of 4 subjects. INTERVENTION: Commercially available magnetic stimulators with round magnetic coils (MCs) were used. Protocol 1 measured the effects of FMS on rectal pressure by placing the MC on the transabdominal and lumbosacral regions. Protocol 2 consisted of a 5-week stimulation period to investigate the effects of FMS on total and segmental colonic transit times (CTTs). MAIN OUTCOME MEASURE: An increase in rectal pressure and a decrease in CTT by magnetic stimulation. RESULTS: Data were averaged and the standard error of the mean was calculated. Statistically significant changes in rectal pressure and CTT were also measured. Rectal pressures increased from 26.7 +/- 7.44cmH(2)O to 48.0 +/- 9.91cmH(2)O, p =.0037, with lumbosacral stimulation, and from 30.0 +/- 6.35cmH(2)O to 42.7 +/- 7.95cmH(2)O, p =.0015, with transabdominal stimulation. With FMS, the mean CTT decreased from 105.2 to 89.4 hours, p =.02. CONCLUSION: FMS is able to stimulate the colon and reduce CTT. FMS is a noninvasive, technological advancement for managing neurogenic bowel in patients with SCI.     

Pelvic movement and interface pressure distribution during manual wheelchair propulsion

OBJECTIVE: To investigate the movement of the ischial tuberosities and the redistribution of interface pressure during manual wheelchair propulsion. DESIGN: Measurement of ischial tuberosity positions and comparison with corresponding position of the zones of peak pressure by using independent samples t tests. Analysis of variance was used to compare peak and average pressures under static and dynamic conditions. SETTING: Human locomotion laboratory. PARTICIPANTS: Ten subjects with spinal cord injury (SCI) and 10 individuals with no disabilities. INTERVENTIONS: Manual wheelchair propulsion on a stationary wheelchair ergometer at the subject's maximum propulsion speed. MAIN OUTCOME MEASURES: Seat interface pressure and the 3-dimensional position of the pelvis were measured with a pressure mat and an optical motion analysis system. RESULTS: During wheelchair sprinting, the ischia were located at 19.2+/-11.7 mm behind the corresponding peak pressure locations. The anteroposterior rocking of the pelvis was 11.2 degrees and 5.2 degrees for the normal and SCI group, respectively. The average interface pressure over the ischial tuberosity area was lower under dynamic conditions. It was also observed in the SCI group that there was a concentration of high-pressure gradients around the peak pressure areas of the buttock during dynamic propulsion. CONCLUSION: Peak pressure locations did not concur exactly with the ischial tuberosities during propulsion. The movements of the ischial bone and the cyclic loading imposed on the tissue underneath the ischial tuberosities during dynamic conditions may have implications for the etiology of decubitus ulcers.     

Blood flow in the gluteus maximus of seated individuals during electrical muscle stimulation

Blood flow was measured under the ischial tuberosites of seated individuals during electrical stimulation of the gluteus maximus muscles. Eight able-bodied and six spinal cord injured subjects were studied. Muscle blood flow was measured via radioactive tracer (133xenon) clearance. Retention of xenon in adipose tissue prevented accurate measurement of blood flow in cutaneous and subcutaneous tissue. Average muscle blood flow for both subject groups was increased during stimulation as compared to rest. All subjects showed an increase in muscle blood flow during stimulation. The statistical significance from a paired student t-test was greater for able-bodied subjects (p less than .05) than for spinal cord injured subjects (p = .12). The increase in muscle blood flow produced by electrical muscle stimulation in seated individuals supports the hypothesis that electrical muscle stimulation can help prevent pressure sores.     

Long-term prevention of pressure ulcers in high-risk patients: a single case study of the use of gluteal neuromuscular electric stimulation

OBJECTIVE: To evaluate the efficacy of gluteal neuromuscular electric stimulation (NMES) using implanted percutaneous electrodes to improve regional tissue health and decrease the risk of pressure ulcer development. DESIGN: Case study of long-term use of gluteal NMES. SETTING: Community. PARTICIPANT: A patient with a C4-level American Spinal Injury Association grade A spinal cord injury, 22 years postinjury at study enrollment, and a clinical history of regular grade II and occasional IV ischial pressure ulcers. INTERVENTION: Gluteal NMES using an electric stimulation system comprising a combination of implanted percutaneous electrodes and an external stimulator (controller). MAIN OUTCOME MEASURES: Objective measurements of tissue health comprising evaluation of gluteal muscle thickness, interface pressures, and regional blood flow. Subjective self-reported sitting tolerance. RESULTS: Increased gluteal muscle thickness and blood flow together with reduced regional interface pressures occurred. Weight-shifting because of alternating left and right gluteal NMES became more effective over time as the muscles strengthened. Sitting tolerance more than doubled. CONCLUSIONS: A gluteal NMES system has been developed that provides both improved regional tissue health and dynamic weight shifting while seated in the wheelchair. In the current case, regular daily use had a positive impact on multiple indirect indicators of tissue health. Continued use was indicated as the positive effects were lost when stimulation was discontinued.     

Self-controlled dorsal penile nerve stimulation to inhibit bladder hyperreflexia in incomplete spinal cord injury: a case report

Intermittent catheterization is not always successful in achieving continence in spinal cord injury (SCI) and often requires adjunctive methods. Electric stimulation of sacral afferent nerves reduces hyperactivity of the bladder. This report describes application of self-controlled dorsal penile nerve stimulation for bladder hyperreflexia in incomplete SCI. The patient was a 33-year-old man with C6 incomplete quadriplegia who managed his bladder with intermittent self-catheterization and medication. Despite this, he continued to have reflex bladder contractions that he could feel but could not catheterize himself in time to prevent incontinence. We performed cystometry with dorsal penile nerve stimulation and analyzed data of home use of stimulation. During cystometry, the suppressive effect of electric stimulation on hyperreflexic contractions was reliable and reproducible. The patient could start stimulation on sensing bladder contraction, and the suppression of reflex contraction lasted several minutes after stopping brief stimulation. When using stimulation at home, the rate of leakage between catheterization decreased, and catheterized volume increased significantly.     

Effects of absorbent incontinence pads on pressure management mattresses

AIM: The aim of this paper is to report a study to determine the effects of absorbent pads on the pressure-relieving properties of 'standard' and pressure management mattresses. BACKGROUND: Pressure ulcers and incontinence often co-exist. There is a strong association between poor mobility and continence problems and patients using pressure management products are therefore also likely to be using absorbent pads. METHODS: An instrumented articulated anthropometric phantom with simulated soft body 'tissues' in the gluteal and sacral areas was used as the 'subject'. The phantom was raised and lowered on to three mattresses (standard foam, visco-elastic foam and surface-cut foam) in three states: naked, wearing a dry pad (Tena Super, SCA Hygiene AB) and wearing a wet pad. The pressure mapping device Xsensor was used to record the distribution of pressure over the sacral and ischial areas of the phantom. Peak pressure was used as the primary outcome variable and 10 repeats were made on each mattress under each condition. RESULTS: There were substantial and significant differences for all three mattresses in recorded peak pressures between the naked buttocks and the buttocks wearing a dry pad. There were no significant differences between measurements made using the dry vs. wet pad. Peak pressures frequently occurred over areas of pad folds. Additional testing showed that pads that were 'smoothed' by hand had significantly lower peak pressures than 'unsmoothed' pads. CONCLUSIONS: Absorbent pads have a substantial adverse effect on the pressure redistribution properties of mattresses. Pad folds appear to contribute to this effect, which can be ameliorated slightly by smoothing. Absorbent pad manufacturers should consider engineering pads that minimize disruption to pressure management. Further examination of continence and pressure management products is necessary to establish optimum combinations for nursing care.     

Emerging clinical applications of electrical stimulation: opportunities for restoration of function.

Emerging clinical application of electrical stimulation in three systems is reviewed. In the bladder, stimulation of sacral posterior roots reduces reflex incontinence and significantly improves bladder capacity. With the combination of anterior and posterior root stimulation, bladder control can be achieved without the need for rhizotomy. Preliminary research demonstrates that bladder contractions may also be generated by stimulation of the urethral sensory branch of the pudendal nerve, even after acute spinal cord transection, while inhibition of the bladder and control of urge incontinence can be achieved by stimulation of the whole pudendal nerve. Spinal cord stimulation can modulate the activity of the intrinsic cardiac nervous system involved in the regulation of regional cardiac function and significantly reduce the pain associated with angina pectoris. Finally in the area of upper airway disorders, functional electrical stimulation has great potential for increasing life support as well as for quality of life in chronic ailments, particularly obstructive sleep apnea and dysphagia.     

骶神经电刺激治疗顽固性排尿功能障碍

目的观察骶神经电刺激(sacral nerve stimulafion,SNS)治疗顽固性排尿功能障碍的临床效果.方法对1例确诊为顽固性排尿功能患者行骶3孔神经电刺激治疗.结果电刺激治疗8 d后及拔除电极后第1,4,8周,B超测定剩余尿量为0,尿失禁、尿频、尿急等临床症状均明显改善,每次排尿量正常.结论骶神经电刺激能有效地治疗顽固性排尿功能障碍.     

Osteoporosis in women with spinal cord injuries

Decreased bone density and increased fracture risk are seen in patients with SCI. The bone resorption rate is markedly increased. Hypercalciuria, low PTH, and low 1,25 (OH)2 vitamin D are commonly seen. Bed-rest studies show similar findings, but of lesser magnitude. Therapies to treat or prevent osteoporosis include optimal nutrition (with care to avoid exacerbating hypercalciuria). Weight-bearing or functional electrical stimulation cycle ergometry may prevent some of the bone loss, especially in acutely injured patients. Estrogen should be considered in postmenopausal or amenorrheic women, but not if they are at high risk of thromboembolism. More research on effects of estrogen is needed in this population. Bisphosphonates may also help prevent the acute bone loss; oral routes must not be used in recumbent patients. Thiazides could be useful as adjunct therapy.     

Bilateral anterior superior iliac spine pressure ulcers: a case report

The most frequent sites for pressure ulcers are the occiput, sacrum, ischial tuberosities, trochanters, lateral malleoli, and posterior heels. A 27-year-old woman with Wegener's granulomatosis was admitted to our rehabilitation unit after spending 65 days in an intensive care unit and 40 days in an internal medicine ward. She required mechanical ventilation because of respiratory failure. Adequate oxygenation was only achieved in the prone position. As a result, she developed bilateral anterior superior iliac spine pressure ulcers. Pressure ulcers in this location have not been reported in the literature. Complicating factors included variable levels of oxygenation, malnutrition, anemia, and steroid therapy. Complete healing, documented with serial photographs, occurred over 9 months. Although prone positioning can improve pulmonary gas exchange, it exposes the patient to unique complications. When it is required, specific care should be directed to the unusual weight-bearing surfaces to avoid pressure ulcers.