Biomedical subjects

W Thomas Edwards

Publications and source records attributed to W Thomas Edwards.

5 recordsLinked to original sources

PubMed2006

Preamputation pain and acute pain predict chronic pain after lower extremity amputation.

UNLABELLED: Although previous research suggests that preamputation pain is a risk factor for pain after amputation, little is known about the association between acute postsurgical pain and chronic amputation-related pain. The current prospective study examined the associations of preamputation pain and acute postamputation pain with chronic amputation-related pain. The sample consisted of patients with lower limb amputation (N = 57) who provided both preamputation and postamputation data during a 2-year study period. Preamputation pain intensity and duration were assessed before amputation; acute phantom limb pain (PLP) and residual limb pain (RLP) intensity were assessed on postsurgical days 4 and 5. Acute PLP intensity was the only significant independent predictor of chronic PLP intensity at 6 and 12 months after amputation, whereas preamputation pain intensity was the only significant predictor of chronic PLP intensity at 24 months. Similarly, acute RLP was found to be the best overall predictor of chronic RLP. Other variables (age, gender, level and etiology of amputation, amount of postsurgical pain medication, and duration of preamputation pain) were not associated with chronic pain. These results suggest that higher levels of pain either before or soon after amputation might help to identify individuals at greatest risk for chronic pain problems and most in need of early, intensive pain interventions. PERSPECTIVE: This study suggests that both preamputation pain and acute pain soon after amputation might be associated with bothersome chronic pain. The results support further research on acute pain mechanisms and the effectiveness of early interventions aimed at preventing or managing amputation-related pain.

Acute Disease↗

PubMed2006

Effect of joint stiffness on standing stability.

Standing balance depends on the effective control of the torques at the ankle, knee, and hip. Stiffness at each joint and feedback proportional to joint angle contributes to these torques and to postural stability. This study examines the interaction of multiple joints on the minimum effective joint stiffnesses needed to maintain quiet standing and determines the inherent patterns of sway motion based on dynamic calculations of a four-link, three-joint, sagittal plane model. The equations of motion for quiet standing are solved to obtain the limits of stability for an individual (75 kg, 1.753 m tall) considering different combinations of joint stiffness. These calculations demonstrate that the single-link inverted pendulum model provides a less conservative estimate of minimum stiffness. That is, more stiffness is required at each joint to preserve stability when rotation is permitted at the knee and hip joints. Based on these analyses, the well recognized ankle and hip balance strategies appear to correspond to variations of the inherent patterns of motion of the lowest frequency mode. Additional calculations show that the stability decreases with an increase in body mass index. The present results quantify the interaction of the combined active and passive stiffnesses at the ankle, knee, and hip, and identify the minimum conditions needed for quiet standing. These criteria define standing-balance stability thresholds needed to assess the risk of falling and to guide rehabilitation.

Biomechanical Phenomena↗

PubMed2006

Pain management.

This article provides information regarding treatments for the management of moderate to severe pain in patients who are at the end of life. Discussion focuses on the use of strong opioids and adjuvant analgesics. Special attention also is given to the most frequently used forms of interventional pain management. Although pain in terminally ill patients is not always related to cancer, many of the studies cited in this article were performed in cancer patients, a model that informs much of what is presented.

Adjuvants, Anesthesia↗

PubMed2004

Trial of amitriptyline for relief of pain in amputees: results of a randomized controlled study.

OBJECTIVE: To evaluate whether amitriptyline is more effective than placebo in improving phantom limb pain or residual limb pain. DESIGN: Randomized controlled trial of amitriptyline for 6 weeks. SETTING: University hospital. PARTICIPANTS: Thirty-nine persons with amputation-related pain lasting more than 6 months. INTERVENTION: Six-week trial of amitriptyline (titrated up to 125 mg/d) or an active placebo (benztropine mesylate). MAIN OUTCOME MEASURES: Analyses were conducted to examine whether there was a medication group effect on the primary outcomes (average pain intensity) and secondary outcome measures (disability, satisfaction with life, handicap). RESULTS: No significant differences were found between the treatment groups in outcome variables when controlling for initial pain scores. CONCLUSIONS: Our findings do not support the use of amitriptyline in the treatment of postamputation pain.

Adult↗

PubMedDate not supplied

Measurement and analyses of the effects of adjacent end plate curvatures on vertebral stresses.

BACKGROUND: Vertebral end plates of the lumbosacral spine have various degrees of concavity and convexity. It is believed that the shape of the end plates alters the distribution of loads transferred along the spine, between the vertebrae. Animal models have been regularly used in the design and development of vertebral disc implants and cages; to date, very little information is known about the animal vertebral end plate curvature. PURPOSE: The purpose was to measure and analyze the end plate curvature in the cadaver human male-female, chimpanzee, and canine lumbar vertebral bones. STUDY DESIGN/SETTING: Nondestructive and nontouching scanning method was designed to obtain curvature in anterior-posterior and medial-lateral directions in the cadaver bones. Statistical analysis was performed on the data collected, and this data was then used to create a biomechanical model to evaluate the load transmission. METHOD: Measurements in anterior-posterior and medial-lateral directions were performed on human, canine, and chimpanzee cadaver lumbar bones to obtain accurate data for the end plate curvatures. Six sets of measurements (on human male-female L4 lower to S1 upper end plates) were performed. A parametric vertebral motion segment model (with and without posterior elements) that includes the experimental curvature information was developed. The characteristic kidney-shaped cross-sectional model was created using a parametric equation. This model was used to perform finite element analyses investigating the effects of the location of maximum curvature on the stress distributions. RESULTS: The measurements for different species showed that the canine and chimpanzees, the quadrupeds, have entirely different curvature of their upper end plates compared with those in humans, the bipeds. Also, the curvatures of the human S1 upper end plates are significantly different from the rest of the vertebrae. This is a very useful piece of information in the comparison of these species. The stress distribution varied as the location of the maximum curvature shifted from the center to a more posterior position. The stresses in the vertebral core were found to decrease, with the shell taking more loads. CONCLUSIONS: This provides essential information for rehabilitation and surgical techniques, including designs for various interbody devices such as fusion cages, bone grafts, and disc prosthesis.

Animals↗