Bone-loading response varies with strain magnitude and cycle number.

date: 11/01/2001
author: Cullen DM, Smith RT, Akhter MP.
publication: J Appl Physiol. 2001 Nov;91(5):1971-6.
pubmed_ID: 11641332

Mechanical loading stimulates bone formation and regulates bone size, shape, and strength. It is recognized that strain magnitude, strain rate, and frequency are variables that explain bone stimulation. Early loading studies have shown that a low number (36) of cycles/day (cyc) induced maximal bone formation when strains were high (2,000 microepsilon) (Rubin CT and Lanyon LE. J Bone Joint Surg Am 66: 397-402, 1984). This study examines whether cycle number directly affects the bone response to loading and whether cycle number for activation of formation varies with load magnitude at low frequency. The adult rat tibiae were loaded in four-point bending at 25 (-800 microepsilon) or 30 N (-1,000 microepsilon) for 0, 40, 120, or 400 cyc at 2 Hz for 3 wk. Differences in periosteal and endocortical formation were examined by histomorphometry. Loading did not stimulate bone formation at 40 cyc. Compared with control tibiae, tibiae loaded at -800 microepsilon showed 2.8-fold greater periosteal bone formation rate at 400 cyc but no differences in endocortical formation. Tibiae loaded at -1,000 microepsilon and 120 or 400 cyc had 8- to 10-fold greater periosteal formation rate, 2- to 3-fold greater formation surface, and 1-fold greater endocortical formation surface than control. As applied load or strain magnitude decreased, the number of cyc required for activation of formation increased. We conclude that, at constant frequency, the number of cyc required to activate formation is dependent on strain and that, as number of cyc increases, the bone response increases.

Case study to evaluate a standing table for managing constipation.

date: 06/01/2001
author: Hoenig H, Murphy T, Galbraith J, Zolkewitz M.
publication: SCI Nurse 2001 Summer;18(2):74-7.
pubmed_ID: 12035465

Standing devices have been advocated as a potentially beneficial treatment for constipation in persons with spinal cord injury (SCI); however, definitive data are lacking. A case of a patient who requested a standing table to treat chronic constipation is presented as an illustration of a method to address this problem on an individual patient level. The patient was a 62-year-old male with T12-L1 ASIA B paraplegia who was injured in 1965. The patient was on chronic narcotics for severe, nonoperable shoulder pain. His bowel program had been inadequate to prevent impactions. A systematic approach was used to measure the effects of a standing table on frequency of bowel movements (BMs) and on length of bowel care episodes. There was a significant (p < 0.05) increase in frequency of BMs and a decrease in bowel care time with the use of the standing table 5 times/week versus baseline. For this patient, the use of the standing table was a clinically useful addition to his bowel care program.

Regulation of bone mass by mechanical strain magnitude.

date: 08/01/1985
author: Rubin CT, Lanyon LE.
publication: Calcif Tissue Int. 1985 Jul;37(4):411-7.
pubmed_ID: 3930039

The in vivo remodeling behavior within a bone protected from natural loading was modified over an 8-week period by daily application of 100 consecutive 1 Hz load cycles engendering strains within the bone tissue of physiological rate and magnitude. This load regime resulted in a graded dose:response relationship between the peak strain magnitude and change in the mass of bone tissue present. Peak longitudinal strains below 0.001 were associated with bone loss which was achieved by increased remodeling activity, endosteal resorption, and increased intra-cortical porosis. Peak strains above 0.001 were associated with little change in intra-cortical remodeling activity but substantial periosteal and endosteal new bone formation.

Use of prolonged standing for individuals with spinal cord injuries.

date: 08/01/2001
author: Eng JJ, Levins SM, Townson AF, Mah-Jones D, Bremner J, Huston G.
publication: Phys Ther. 2001 Aug;81(8):1392-9.
pubmed_ID: 11509069

BACKGROUND AND PURPOSE: Prolonged standing in people with spinal cord injuries (SCIs) has the potential to affect a number of health-related areas such as reflex activity, joint range of motion, or well-being. The purpose of this study was to document the patterns of use of prolonged standing and their perceived effects in subjects with SCIs. SUBJECTS: The subjects were 152 adults with SCIs (103 male, 49 female; mean age=34 years, SD=8, range=18-55) who returned mailed survey questionnaires. METHODS: A 17-item self-report survey questionnaire was sent to the 463 members of a provincial spinal cord support organization. RESULTS: Survey responses for 26 of the 152 respondents were eliminated from the analysis because they had minimal effects from their injuries and did not need prolonged standing as an extra activity. Of the 126 remaining respondents, 38 respondents (30%) reported that they engaged in prolonged standing for an average of 40 minutes per session, 3 to 4 times a week, as a method to improve or maintain their health. The perceived benefits included improvements in several health-related areas such as well-being, circulation, skin integrity, reflex activity, bowel and bladder function, digestion, sleep, pain, and fatigue. The most common reason that prevented the respondents from standing was the cost of equipment to enable standing. DISCUSSION AND CONCLUSION: Considering the many reported benefits of standing, this activity may be useful for people with SCI. This study identified a number of body systems and functions that may need to be investigated if clinical trials of prolonged standing in people with SCI are undertaken.

The vertical wheeler: a device for ambulation in cerebral palsy.

date: 10/01/1985
author: Manley MT, Gurtowski J.
publication: Arch Phys Med Rehabilitation. 1985 Oct;66(10):717-20.
pubmed_ID: 4051716
The vertical wheeler is a new mobility aid that was specifically designed to help improve the quality of life for the handicapped child by providing mobility while standing. Results of a clinical trial in a population of patients with cerebral palsy are presented. Criteria were selected to allow evaluation of the rehabilitative effect of the device on the population. Results showed that the children in this cerebral palsy group all benefited from ambulation with the wheeler. Patients with spastic quadriparesis seemed to gain the most immediate benefit. The device contributed to improved mobility, posture, and self-image. The wheeler was safe and fun for the children. It has the potential for improving the psychologic and medical status of the child with severe locomotion impairment.

Indications for a home standing program for individuals with spinal cord injury.

date: 09/01/1999
author: Walter JS, Sola PG, Sacks J, Lucero Y, Langbein E, Weaver F.
publication: J Spinal Cord Med. 1999 Fall;22(3):152-8.
pubmed_ID: 10685379

Additional analyses were conducted on a recently published survey of persons with spinal cord injury (SCI) who used standing mobility devices. Frequency and duration of standing were examined in relation to outcomes using chi square analyses. Respondents (n = 99) who stood 30 minutes or more per day had significantly improved quality of life, fewer bed sores, fewer bladder infections, improved bowel regularity, and improved ability to straighten their legs compared with those who stood less time. Compliance with regular home standing (at least once per week) was high (74%). The data also suggest that individuals with SCI could benefit from standing even if they were to begin several years after injury. The observation of patient benefits and high compliance rates suggest that mobile standing devices should be more strongly considered as a major intervention for relief from secondary medical complications and improvement in overall quality of life of individuals with SCI.

Effects of a dynamic versus a static prone stander on bone material density and behavior in four children with severe cerebral palsy.

date: 03/01/2002
author: Gudjonsdottir, Bjorg MS/PT, Vicki Stemmons Mercer, PhD, PT
publication: Pediatric Physical Therapy 2002;14:38-46.
pubmed_ID: 17053680

PURPOSE: in this case series, we examined how two types of prone standers affected bone material density and behavioral variables in four children of preschool age with severe cerebral palsy. METHODS: In phase one, four children of preschool age participated in an eight-week standing program, standing for 30 minutes a day, five days a week. Two children stood in a conventional stander, and two stood in a new type of motorized (dynamic) stander that provides intermittent weight bearing. Measurements of bone material density before and after the program revealed increases in bone material density in both children who used a dynamic stander and one child who used a static stander. In phase two, all four subjects stood in both types of stander during three separate test sessions. RESULT: Measures of behavioral variables, including behavioral state, reactivity, goal directedness, and attention span, indicated little or no effect of type of stander on behavior. CONCLUSIONS: These results suggest there is potential value in additional research concerning the effects of static and dynamic standers on bone material density and behavior in children with cerebral palsy.

Follow-up assessment of standing mobility device users.

date: 10/01/1998
author: Dunn RB, Walter JS, Lucero Y, Weaver F, Langbein E, Fehr L, Johnson P, Riedy L.
publication: Assistive Technology. 1998;10(2):84-93.
pubmed_ID: 10339284

The use of standing devices by spinal cord-injured subjects was investigated through a national survey of a sample of individuals who returned their manufacturer’s warranty card to two companies. We obtained a 32% response rate (99/310). The majority of respondents were male (87%) with a median age between 41 and 50 years. Seventy-seven percent were paraplegic and 21% were quadriplegic. Forty percent had between 1 and 5 years experience with their device, and 84% of those responding were currently using their standing device. Forty-one percent used their standing device one to six times a week; two-thirds stood between 30 minutes and 1 hour for each use. Less than 10% of subjects experienced any side effects, such as nausea or headaches, from standing. Twenty-one percent of subjects reported being able to empty their bladder more completely. There was also a favorable response by some individuals on the effects of the standing devices on bowel regularity, reduction of urinary tract infections, leg spasticity, and number of bedsores. Finally, 79% of subjects highly recommended use of standing devices to other people with spinal cord injury. The positive responses of individuals using standing devices is a strong recommendation for the assistive technology community to make these devices more available to individuals with spinal cord injury.

Tilt table standing for reducing spasticity after spinal cord injury.

date: 10/01/1993
author: Bohannon RW
publication: Arch Physical Medicine Rehabilitation. 1993 Oct;74(10):1121-2.
pubmed_ID: 8215868

A patient with a T12 spinal cord injury and intractable extensor spasms of the lower extremities participated in tilt table standing trial on 5 nonconsecutive days to determine if the intervention would affect his spasticity and spasms. Each day’s standing trial was followed by an immediate reduction in lower extremity spasticity (measured using the modified Ashworth scale and pendulum testing). Standing was also accompanied by a reduction in spasms that lasted until the following morning. The reduction of spasms was particularly advantageous to the performance of car transfers. Tilt table standing merits further examination as a physical treatment of spasms that accompany central nervous system lesions.