Biomedical subjects

Douglas T Hutchinson

Publications and source records attributed to Douglas T Hutchinson.

8 recordsLinked to original sources

PubMed2004

Residual function in peripheral nerve stumps of amputees: implications for neural control of artificial limbs.

PURPOSE: It is not known whether motor and sensory pathways associated with a missing or denervated limb remain functionally intact over periods of many months or years after amputation or chronic peripheral nerve transection injury. We examined the extent to which activity on chronically severed motor nerve fibers could be controlled by human amputees and whether distally referred tactile and proprioceptive sensations could be induced by stimulation of sensory axons in the nerve stumps. METHODS: Amputees undergoing elective stump procedures were invited to participate in this study. Longitudinal intrafascicular electrodes were threaded percutaneously and implanted in severed nerves of human amputees. The electrodes were interfaced to an amplifier and stimulator system controlled by a laptop computer. Electrophysiologic tests were conducted for 2 consecutive days after recovery from the surgery. RESULTS: It was possible to record volitional motor nerve activity uniquely associated with missing limb movements. Electrical stimulation through the implanted electrodes elicited discrete, unitary, graded sensations of touch, joint movement, and position, referring to the missing limb. CONCLUSIONS: These findings indicate that both central and peripheral motor and somatosensory pathways retain significant residual connectivity and function for many years after limb amputation. This implies that peripheral nerve interfaces could be used to provide amputees with prosthetic limbs that have more natural feel and control than is possible with current myoelectric and body-powered control systems.

Action Potentials↗

PubMed2003

Bilateral simultaneous open carpal tunnel release: a prospective study of postoperative activities of daily living and patient satisfaction.

PURPOSE: The purpose of this study was to determine patient function and satisfaction prospectively after bilateral simultaneous open carpal tunnel release (CTR). METHODS: Twenty patients (40 CTR) completed a questionnaire regarding postoperative activities of daily living (ADL), return to work, procedure satisfaction (visual analog scale), and willingness to have the surgery again. RESULTS: The average patient age was 43 years (range, 23-73 y). The hardest task was opening a jar; the easiest task was using the bathroom. Other tasks on the list in descending order of difficulty included driving, household chores, carrying groceries, buttoning, bathing, cooking, writing, dressing, shopping, holding a book, eating, computer use, and holding a phone. Average return to work was 2.6 weeks (range, 3 d-6 wk). Average satisfaction with the surgery was 9.6 of 10 (range, 8-10); 20 of 20 patients (100%) would have the bilateral simultaneous surgery again. CONCLUSIONS: These data are useful for patient education and decision making when considering surgery in patients with bilateral carpal tunnel syndrome, and show that bilateral simultaneous open CTR is a feasible and useful procedure.

Activities of Daily Living↗

PubMed2003

Cyclic loading of olecranon fracture fixation constructs.

BACKGROUND: Despite the good results that are usually reported after fixation at the sites of olecranon fractures and osteotomies, problems such as loss of fixation, nonunion, and the need for revision surgery are still encountered. Various types of fixation have been recommended, but few have been evaluated with use of clinically relevant cyclic load testing at appropriate levels of stress. The purpose of the present study was to test multiple olecranon fixation techniques under physiologic cyclic loads. METHODS: We studied ten cadaveric elbows with use of cyclic loading that simulated (1) active range of motion and (2) pushing up from a chair. Each specimen underwent fixation of a simulated 50% transverse olecranon fracture with use of intramedullary and cortically fixed tension band constructs (in randomized order) followed by fixation with a 7.3-mm-diameter cancellous screw with and without a tension band. Displacement transducers were placed posteriorly on the tension side and anteriorly near the articular surface. RESULTS: Both configurations involving the 7.3-mm-diameter cancellous screw provided the most stable fixation-nearly five times better than that provided by the Kirschner-wire techniques. Use of the tension band in conjunction with the intramedullary screw improved the stability of fixation. In none of the constructs did the AO tension band result in compression across the osteotomy gap. CONCLUSIONS AND CLINICAL RELEVANCE: The use of a 7.3-mm screw in conjunction with a tension band provided better fixation of simulated displaced transverse fractures than did the use of Kirschner wires in conjunction with a tension band or the use of a screw only. The AO principle of converting posterior tensile forces to articular compressive forces was not demonstrated in this study. We therefore question the validity of the tension band concept in olecranon fracture fixation and recommend passive rather than active range of motion in the immediate postoperative period to limit fracture distraction.

Analysis of Variance↗

PubMed2003

Pain levels after injection of corticosteroid to hand and elbow.

The goal of this study was to examine temporal pain response after injection of corticosteroid to the upper extremity (hand and elbow). Visual analog pain questionnaires were prospectively distributed to 133 consecutive patients, and pain levels were recorded for 5 days after injection. Ninety-four patients (71%) completed the questionnaire. Forty-seven (50%) of the 94 patients did not have increased pain after injection; the other 47 patients had increased pain after injection. The increased pain in 39 (83%) of the 47 patients resolved by day 5, lasting a mean of 1.2 days, and these 39 patients eventually had mean pain improvement of 71%. At day 5, 8 (17%) of the 47 patients had increased postinjection pain levels equal to or greater than their preinjection pain. The percentage of patients who transiently experienced increased pain after corticosteroid injection is quite high (50%), but most symptoms abated by day 2. We believe that these data are important for patient education.

Adrenal Cortex Hormones↗

PubMedDate not supplied

Both-bone forearm osteotomy for supination contracture: a cadaver model.

PURPOSE: To quantify the magnitude of rotational correction possible when comparing a single forearm bone osteotomy and fixation with stepwise osteotomy and fixation of both bones in a cadaver model and to determine if the order in which the stepwise osteotomies are performed influences the amount of correction. METHODS: Ten fresh-frozen cadaveric forearms were fixed to a frame positioned in the field of view of a motion-capture system. An experimental supination contracture was induced in full supination. Cadaver forearms were assigned randomly to group I (ulna osteotomy, rotation, plating) or group II (radius osteotomy, rotation, plating). Cadavers in group I were used later in group III (ulna + radius) by completing a radial osteotomy, rotation, and fixation in the forearms with the plated ulna. Similarly the specimens assigned to group II were used later in group IV (radius + ulna) by completing an ulna osteotomy, rotation, and fixation in the forearms with the plated radiuses. Measurements of forearm pronation were made after single-bone (groups I, II) and stepwise both-bone (groups III, IV) rotational osteotomies. RESULTS: Stepwise rotational osteotomy and fixation of the ulna followed by the radius produced significantly more corrective pronation (101 degrees) than rotating the radius followed by the ulna (65 degrees). Rotating the radius gave only moderate correction (58 degrees) and minimal correction was produced by ulna osteotomy alone (15 degrees). CONCLUSIONS: Rotational osteotomy of both forearm bones can create approximately 100 degrees of correction when performed at the proximal ulna followed by the distal radius. If less rotation is needed then the distal radius osteotomy alone can provide approximately 60 degrees of correction.

Biomechanical Phenomena↗

PubMedDate not supplied

The effect of corticosteroid injection for trigger finger on blood glucose level in diabetic patients.

PURPOSE: To determine how corticosteroid injections for trigger finger affect the blood glucose level in diabetic patients and the clinical results of those injections. METHODS: Eighteen diabetic patients receiving a methylprednisolone injection for a single trigger finger were studied. Six patients had type I (juvenile-onset) diabetes and 12 patients had type II (adult-onset) diabetes. Patients recorded their usual blood glucose measurements and then they recorded their blood glucose measurements for 5 days after injection. Clinical efficacy of the injections was measured by avoidance of surgery. RESULTS: There were 3 men and 15 women with an average age of 58 years. The blood glucose level increased after corticosteroid injection for all patients. The first morning after injection showed the biggest increase in blood glucose level: 73% more than the average preinjection levels. By the fifth morning after injection the blood glucose levels still were increased by 26% more than the preinjection levels. This trend was marked particularly in type I diabetic patients, who had an average blood glucose level increase the first morning after injection of 145%, which decreased over 5 days to 22% greater than baseline levels. Sixteen patients had follow-up evaluation over a period of 1 year and of these 16 patients 7 required surgery for this condition. CONCLUSIONS: A digital injection of the corticosteroid methylprednisolone acetate in diabetic patients with trigger finger causes a hyperglycemic effect that lasts for at least 5 days but can help prevent the need for surgery more than half the time. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Adult↗

PubMedDate not supplied

The proximal ulna: An anatomic study with relevance to olecranon osteotomy and fracture fixation.

The purpose of this study was to define the proximal ulna anatomy with respect to olecranon osteotomy and fracture fixation. Thirty-nine cadaver elbows were dissected. The mean ulnar length (triceps insertion to ulnar styloid) was 26.0 cm (range, 27.1-29.0 cm). The mean distance from the triceps insertion to the ulna's varus angulation point was 7.6 cm (range, 6.5-9.0 cm). The distance ratio from the triceps insertion to the proximal ulnar angle to the overall ulna length was consistent, averaging 0.29 (range, 0.23-0.33). The mean diameter of the medullary canal at the ulnar angulation point could accommodate a 7.0- or 7.3-mm intramedullary screw. The mean width of the olecranon bare area (lacking articular cartilage) was 0.53 cm (range, 0.13-0.97 cm), and the mean distance from the triceps insertion to the corresponding area of the bare spot on the dorsal cortex was 2.1 cm (range, 1.4-2.5 cm).

Cadaver↗

PubMedDate not supplied

Use of the elbow compass universal hinge in pediatric patients.

The purpose of this study was to review the Compass Universal Hinge dynamic elbow external fixator in pediatric conditions. Eight patients with diagnoses of ulnar club hand (n = 2), proximal radial synostosis with hypoplastic coronoid (n = 1), pterygium cubitale (n = 2), and elbow arthrofibrosis (n = 3) were identified. Indications for fixator placement were to maintain elbow stability during forearm lengthening (two cases), protect a coronoid reconstruction (one case), increase range of motion via the fixator (two cases), and maintain stability and increase range of motion after open release (three cases). There were five boys and three girls with an average age at surgery of 11.5 (range 3-19) years. In each case, the goal for fixator use was achieved: both forearm lengthenings were completed without elbow instability, the coronoid reconstruction healed in good position, and four of five patients obtained increased range of motion via the fixator (average improved arc of motion of 31 degrees), with all elbows remaining reduced and stable. Complications included four pin tract infections, one of which became osteomyelitis; two broken/loose pins; and two cases of decreased elbow range of motion. Average follow-up was 29 (range 3-62) months. Use of the Compass Universal Hinge dynamic external fixator can be adapted to children and has proven useful in managing certain difficult conditions.

Adolescent↗