Barry Goldstein

Skin response to repetitive mechanical stress : A new experimental model in pig

OBJECTIVES To develop a new animal model for investigating the relations between interface stresses at the skin, adaptation, and breakdown. There were two hypotheses. (1) In skin subjected to varying types of repetitive mechanical stress, the tissue response depends on the direction and magnitude of the load. As the shear stress increases, tissue breakdown occurs earlier. (2) In skin subjected to repetitive mechanical stress of longer duration, there will be evidence of tissue adaptation. DESIGN Multiple case control, single-blind. INTERVENTIONS Varying combinations of normal and shear mechanical loads are applied to pigs skin for short durations (breakdown studies) or longer durations (adaptation studies). MAIN OUTCOME MEASURES Gross evidence of breakdown (visual inspection of skin) and microscopic changes (eg, histologic features of breakdown; thickness of epidermis and dermis; the length and shape of the basement membrane; concentration of inflammatory cells, mast cells, and fibroblasts; and quantity of elastin fibers). RESULTS The instrumentation was reliable and a significant improvement over past models in that shear forces were delivered and measured in a controlled manner. The animal model and tissue methodology provided consistent results, and it was found that skin breakdown occurred earlier as shear forces were increased. Evidence of tissue adaptation occurred in the long-term experiments, although corresponding morphologic changes have been difficult to elucidate. CONCLUSIONS To address the problem of skin breakdown, new animal models are strongly needed to better understand basic biologic processes related to pressure ulcer development.

The Ability of Multi-Site, Multi-Depth Sacral Lateral Branch Blocks to Anesthetize the Sacroiliac Joint Complex

OBJECTIVE To determine the physiologic effectiveness of multi-site, multi-depth sacral lateral branch injections. DESIGN Double-blind, randomized, placebo-controlled study. SETTING Outpatient pain management center. PATIENTS Twenty asymptomatic volunteers. BACKGROUND The dorsal innervation to the sacroiliac joint (SIJ) is from the L5 dorsal ramus and the S1-3 lateral branches. Multi-site, multi-depth lateral branch blocks were developed to compensate for the complex regional anatomy that limited the effectiveness of single-site, single-depth lateral branch injections. INTERVENTIONS Bilateral multi-site, multi-depth lateral branch green dye injections and subsequent dissection on two cadavers revealed a 91% accuracy with this technique. Session 1: 20 asymptomatic subjects had a 25-g spinal needle probe their interosseous (IO) and dorsal sacroiliac (DSI) ligaments. The inferior dorsal SIJ was entered and capsular distension with contrast medium was performed. Discomfort had to occur with each provocation maneuver and a contained arthrogram was necessary to continue in the study. Session 2: 1 week later; computer randomized, double-blind multi-site, multi-depth lateral branch blocks injections were performed. Ten subjects received active (bupivicaine 0.75%) and 10 subjects received sham (normal saline) multi-site, multi-depth lateral branch injections. Thirty minutes later, provocation testing was repeated with identical methodology used in session 1. OUTCOME MEASURES Presence or absence of pain for ligamentous probing and SIJ capsular distension. RESULTS Seventy percent of the active group had an insensate IO and DSI ligaments, and inferior dorsal SIJ vs 0-10% of the sham group. Twenty percent of the active vs 10% of the sham group did not feel repeat capsular distension. Six of seven subjects (86%) retained the ability to feel repeat capsular distension despite an insensate dorsal SIJ complex. CONCLUSION Multi-site, multi-depth lateral branch blocks are physiologically effective at a rate of 70%. Multi-site, multi-depth lateral branch blocks do not effectively block the intra-articular portion of the SIJ. There is physiological evidence that the intra-articular portion of the SIJ is innervated from both ventral and dorsal sources. Comparative multi-site, multi-depth lateral branch blocks should be considered a potentially valuable tool to diagnose extra-articular SIJ pain and determine if lateral branch radiofrequency neurotomy may assist one with SIJ pain.

Diabetes mellitus in individuals with spinal cord injury or disorder

Abstract Background/Objective: To examine diabetes prevalence, care, complications, and characteristics of veterans with a spinal cord injury or disorder (SCI/D). Methods: A national survey of veterans with an SCI/D was conducted using Behavioral Risk Factor Surveillance System (BRFSS) survey questions. Data were compared with national Centers for Disease Control and Prevention BRFSS data for veteran and nonveteran general populations. Results: Overall prevalence of diabetes in individuals with an SCI/D was 20% (3 times higher than in the general population). Veterans with an SCI/D and veterans, in general, had a higher prevalence of diabetes across all age groups; however, those with an SCI/D who were 45 to 59 years of age had a higher prevalence than other veterans. One fourth of the persons with an SCI/D and diabetes reported that diabetes affected their eyes or that they had retinopathy (25%), and 41 % had foot sores that took more than 4 weeks to heal. More veterans, both with (63%) and without an SCI/D (60%), took a class on how to manage their diabetes than the general population (50%). Veterans with an SCI/D and diabetes were more likely to report other chronic conditions and poorer quality of life than those without diabetes. Conclusions: Diabetes prevalence is greater among veterans with an SCI/D compared with the civilian population, but is similar to that of other veterans, although it may occur at a younger age in those with an SCI/D. Veterans with an SCI/D and diabetes reported more comorbidities, more slow-healing foot sores, and poorer quality of life than those without diabetes. Efforts to prevent diabetes and to provide early intervention in persons with SCI/D are needed.

Collagen fibril diameters increase and fibril densities decrease in skin subjected to repetitive compressive and shear stresses

Understanding microstructural changes that occur in skin subjected to repetitive mechanical stress is crucial towards the development of therapies to enhance skin adaptation and load tolerance in patients at risk of skin breakdown (e.g. prosthesis users, wheelchair users). To determine if collagen fibril diameter, collagen fibril density, dermal thickness, epidermal thickness, basement membrane length, and dermal cell density changed in response to repetitive stress application, skin subjected to moderate cyclic compressive and shear stresses for 1h/d, 5d/week, for 4 weeks was compared with skin from an unstressed contralateral control. The lateral aspects of the hind limbs of 12 Landrace/Yorkshire pigs were used. Skin from under the stressed site and a contralateral control site was processed for electron microscopy and light microscopy analysis. Electron microscopy results demonstrated significant (p<0.01) increases in collagen fibril diameter of 15.9%, 22.4%, and 22.9% for the upper, mid, and lower layers of the dermis, respectively, for the stressed skin compared with the control skin. Collagen fibril density (fibrils/unit cross-sectional area) decreased significantly for stressed vs. control by 19.8%, 29.2%, and 31.8% for the upper, mid, and lower layers, respectively. Light microscopy results demonstrated trends of a decrease in dermal thickness and an increase in cell density for stressed vs. control samples, but the differences were not significant. Differences in epidermal thickness and basement membrane length were not significant. These results demonstrate that quantifiable changes occur in collagen fibril architecture but not in the gross tissue morphology following in vivo cyclic loading of pig skin.

Clinical Assessment and Management of Obesity in Individuals With Spinal Cord Injury: A Review

Abstract Background: Diagnosing and managing obesity in individuals with spinal cord injury (SCI) remain challenging. Methods: Literature on the epidemiology, impact, and management of obesity in individuals with SCI was reviewed. Findings: Although nearly 66% of individuals with SCI are either overweight or obese, little guidance is available to measure and monitor obesity in the clinical setting. The use of anthropometric indices and specific cut points available for able-bodied persons is limited by the body composition changes that follow SCI. Indices of upper body obesity warrant examination in SCI because they provide an index of central obesity, which is more closely linked to some obesity-related conditions than is overall obesity. Investigations into the sequelae of excess body fat and its distribution are also needed in SCI because past research in this area has been inconclusive. Although limited, evidence regarding obesity interventions in SCI may be promising. Conclusions: The best anthropometric tool to define obesity in the clinical setting remains unknown. SCI-specific assessment tools and a better understanding of the sequelae of excess body weight will lead to better targeting of prevention and treatment efforts. More research is needed on the individual components of a weight management program unique to SCI. Until then, providers are urged to use a team approach and draw on existing resources and applicable research in able-bodied individuals to facilitate weight management in individuals with SCI.

Incidence of Fractures in a Cohort of Veterans With Chronic Multiple Sclerosis or Traumatic Spinal Cord Injury

OBJECTIVE To measure skeletal fractures in a cohort of veterans with spinal cord dysfunction (SCD) due to multiple sclerosis (MS) or trauma-related spinal cord injury (SCI). DESIGN Retrospective cohort analysis. SETTING Database search. PARTICIPANTS Study subjects were a subset of the 1996 Veterans Health Administration (VHA) National Spinal Cord Dysfunction Registry, from which 8150 patients were identified with either MS (n=1789) or SCI (n=6361). Inpatient and outpatient encounters for nonaxial fractures, based on International Classification of Diseases, Ninth Revision, Clinical Modification codes, were identified through VHA administrative databases between October 1996 and June 2005. VHA Beneficiary Identification Records Locator Subsystem death file identified time of death. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Data from the 1996 VHA National Spinal Cord Dysfunction Registry survey was used to determine duration of disease and motor impairment (4 categories of motor impairment based on self-report of the number of limbs involved and degree of motor loss). Proportional hazard modeling evaluated the time to first fracture and Poisson regression evaluated relative risk (RR) of fracture by cause of SCD and degree of motor impairment, adjusting for age, sex, race, and duration of SCD. RESULTS Subjects were, on average, 52.5 years of age, acquired their SCD 22 years prior, and 386 of 8150 were deceased. During the study period, 4021 fracture encounters were identified representing 1738 unique fractures for 1085 of 7832 subjects, for a mean per-person fracture rate of 3.1 per 100 patient-years at risk. The RR of fracture differed according to cause of SCD and motor impairment. Fracture risk was increased by more than 2-fold in those with some motor impairment (RR=2.33, P<.001), by more than 80% with moderate motor impairment (RR=1.87, P<.001), and almost 70% for those with severe motor impairment (RR=1.67, P<.001), compared with those with little motor impairment. Trauma-related SCI increased the RR of fracture 80% (RR=1.82, P<.001) compared with MS. CONCLUSIONS Persons with SCD have high rates of skeletal fractures. The highest fracture rates occurred in those with some to moderate motor impairment. There were significant differences in risk of fracture according to causal disease, controlling for motor impairment and duration. There appear to be unique contributors to risk of fracture beyond simply disuse.

Rotator Cuff Repairs in Individuals with Paraplegia

Shoulder pain and dysfunction are common problems among those individuals with a spinal cord injury (SCI). Among individuals with SCI who have shoulder pain, the prevalence of rotator cuff tears is 65 TO 71%. To date, there has been little discussion as to the efficacy of various treatments for shoulder pain used in the SCI population. The purpose of this retrospective study was to evaluate the outcome of rotator cuff repairs at the Spinal Cord Injury Center (Veterans Administration Puget Sound Health Care System). Five patients (six shoulders) were identified who had undergone shoulder surgery for rotator cuff tear since 1987. Four individuals (five shoulders) had large rotator cuff tears, and following surgery, none of these repairs resulted in improvement of shoulder function or improvement in active range of motion. The one patient with a smaller tear limited to the supraspinatus had a successful surgical outcome in that he had decreased pain, increased strength, and increased range of motion. There is a general lack of epidemiologic information about shoulder pain in individuals with paraplegia. There is also a remarkable lack of research as to the functional impact of shoulder pain and the outcome of nonsurgical and surgical treatments. This case series, drawn from a population of 511 individuals with spinal cord injury, demonstrates that poor outcome was more likely in those with supraspinatus atrophy, those with upward displacement of the humeral head on x-ray, and in those with tears involving more than one muscle. There is a need for further study of conservative treatment and development of selection criteria for those individuals who are being considered for surgery.

Predictors of pressure ulcer recurrence in veterans with spinal cord injury.

Abstract Background/Objective: To predict recurrence of pressure ulcers (PrUs) in a high-risk populationofveterans with spinal cord injury (SCI). Design:Cross-sectional observational design. Participants: A convenience sample of 64 subjects from 6 Department of Veterans Affairs (VA) SCI Centers who had been admitted to the hospital for the treatment of stage III-IV pelvic PrUs and were healed at the time of discharge back to the community. Main Outcome Measures:Primary outcome measures were pelvic PrU recurrence, defined as selfreported new skin breakdown (stage II or greater) in the pelvic area (not necessarily in the same location as previous ulcer) and time to recurrence. Results:There were no differences between those with/without recurrences with regard to age, age at/level of injury, number of previous ulcers or surgery, rate of or time, to recurrence. Mean age was 56 years; most were white and men, lived at home, and had some college education. Mean time since SCI was 22 years; 28% had tetraplegia; mean number of prior pressure ulcers was 3; and almost one half had a previous ulcer in the same location. The strongest predictor of recurrence in a multivariate logistic regression was African American race (odds ratio = 9.3). Additional predictors included higher scores on the Charlson Co-Morbidity Index (indicating a higher burden of illness), the Salzburg PrU Risk Assessment Scales, and longer sitting time at discharge. Conclusion:Identifying individuals at highest risk for recurrence and developing effective prevention programs are essential rehabilitation goals. We recommend that the unique findings of this exploratory study be considered preliminary until replication of these results is published.

Image processing techniques for quantitative analysis of skin structures

Computer-based image processing and analysis techniques were developed for quantitative analysis of skin structures in color histological sections. Performance was compared with traditional non-image processing counting methods. Skin sections were stained with Massons trichrome, hematoxylin and eosin, picrosirius red, or one of several elastin stains. The image processing software identified the top of the cellular epidermis and the dermal-epidermal junction and then calculated the volume of the cellular layer of the epidermis, epidermal thickness, and the ratio of the dermal-epidermal junction surface area to the in-plane surface area. It also identified cells and collagen and calculated cellular densities and collagen densities in the papillary and reticular layers of the dermis. Attempts to computationally process elastin-stained sections to determine elastin density were unsuccessful. The described techniques were used in a preliminary study to compare mechanically stressed skin with control skin. Results showed significant differences in cellular density in the papillary dermis and collagen density in the reticular dermis for skin subjected to combined shear/compression or tension compared with an unstressed control. Measurements made with the computer technique and traditional technique showed comparable results; the mean difference in measurements for epidermal features was 5.33% while for dermal features it was 2.76%. Significance testing between control and experimental groups showed similar results, though for three of the 28 comparisons the computer method identified a significant difference while the traditional method did not. The computer method took longer to conduct than the traditional method, though with recent advances in computer hardware this time difference would be eliminated.

Axonal sprouting following incomplete spinal cord injury: an experimental model.

Recovery of function following incomplete spinal cord injury may in part result from growth of new connections by spared descending pathways. It has been difficult to demonstrate such anatomical reorganization with traditional anatomic techniques. This study utilizes an immunocytochemical method to demonstrate axonal growth cones within the lumbar spinal cord in rats recovering from an incomplete midthoracic spinal cord injury. Adult rats underwent subtotal section of the midthoracic cord sparing the left lateral funiculus and a portion of the left ventral funiculus. Light microscope immunocytochemistry was performed on sections of lumbar spinal cord with antibodies to identify sprouting axons. These antibodies were used to determine the distribution of growth cones on both sides of the lumbar spinal cord in experimental and control animals. Growth cones were first observed three days after the spinal cord lesion. Specific labeling, similar in appearance to previous reports of growth cone identification, was apparent within the immediate gray and ventral horns on both sides of the cord. These data support the hypothesis of collateral sprouting distal to the lesion site following incomplete spinal cord injury. It further supports the idea that recovery of function following incomplete spinal cord injury is, in part, mediated by spared descending pathways.