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Biomedical subjects

R B Resnick

Publications and source records attributed to R B Resnick.

At least 19 recordsLinked to original sources
PubMed1996

Tibiotalar contact area and pressure distribution: the effect of mortise widening and syndesmosis fixation.

An unconstrained cadaver ankle model was designed to reevaluate the effect of ankle mortise widening and syndesmotic fixation on the load-bearing characteristics of the tibiotalar joint. Tibiotalar contact area, centroid shift, and mean contact pressure were quantified using a pressure-sensitive film technique. Six fresh-frozen below-knee amputation specimens were axially loaded with 500 N in three positions: neutral, 10 degrees of dorsiflexion, and 20 degrees of plantarflexion. The tibiotalar contact area and centroid position for each specimen in its intact state were first determined and then compared with values obtained after syndesmotic fixation, mortise widening of 2 and 4 mm, and deep deltoid ligament transection. Syndesmotic fixation significantly decreased joint contact area but did not consistently affect centroid position. However, unlike earlier studies, which used more constrained ankle fracture models, mortise widening with or without deltoid rupture was not found to significantly affect contact area, centroid position, or joint contact pressure. When statically loaded, the talus moved to its position of maximal congruence in the mortise, rather than displacing laterally along with the lateral malleolus.

Ankle Joint↗
PubMed1995

Deltoid ligament forces after tibialis posterior tendon rupture: effects of triple arthrodesis and calcaneal displacement osteotomies.

Deltoid ligament forces were studied after observing deltoid ligament insufficiency in several post-triple arthrodesis patients. Six fresh-frozen, below-knee amputation specimens were axially loaded. The results demonstrate that a properly positioned triple arthrodesis produced deltoid ligament forces that were similar to those seen with an intact tibialis posterior tendon. A triple arthrodesis in combination with a lateral displacement calcaneal osteotomy produced deltoid ligament forces that were 76% greater than those seen with the intact tibialis posterior tendon (P < .05). A triple arthrodesis in combination with a medial displacement calcaneal osteotomy produced deltoid ligament forces that were 56% less than those seen with the lateral displacement calcaneal osteotomy (P < .01). Patients with longstanding ruptures of the tibialis posterior tendon and associated peritalar subluxation/dislocation may have less than optimal clinical results after triple arthrodesis, unless the hindfoot can be properly reduced, due to persistent elevated forces in the deltoid ligament and resulting ligament laxity. This study suggests that a medial displacement calcaneal osteotomy in combination with a triple arthrodesis may be a viable treatment when the hindfoot cannot be positioned properly.

Ankle Joint↗
PubMed1995

Arthroscopic removal of an osteoid osteoma of the talus: a case report.

This article describes a patient with a 10-year history of persistent ankle pain. Differential diagnosis included osteoid osteoma and anterior ankle impingement. This patient subsequently underwent arthroscopic excision of a lesion on the talar neck following a complete radiographic work-up, which was nondiagnostic. The diagnosis of osteoid osteoma was finalized upon pathologic study of the arthroscopic shavings. The use of a motorized instrument for excision did not preclude pathologic evaluation of the specimen. Therefore, in an accessible location on the talar neck, arthroscopic excision of an osteoid osteoma can be performed.

Adult↗
PubMed1994

Effect of two nonsteroidal antiinflammatory drugs on heterotopic bone formation in a rabbit model.

Using the model described by Michelsson, 24 mature New Zealand white rabbits underwent mechanical induction of heterotopic ossification in the quadriceps of the right hind limb. The rabbits were equally divided into four groups: indomethacin-treated, piroxicam-treated, and their respective controls. The effect of drug therapy on the production of heterotopic bone was assessed by analyzing plain radiographs of the femur using the grading system described by Scott. The results demonstrated that, while indomethacin is effective in decreasing the formation of heterotopic bone, piroxicam--when used in the dosage previously demonstrated to have no deleterious effect on healing bone--is not. The analysis of piroxicam blood levels demonstrated that the experimental piroxicam dose is inadequate to produce effective plasma blood levels in the rabbit. Therefore, any potential benefit from using piroxicam, as opposed to other nonsteroidal antiinflammatory drugs regarding fracture healing and bone remodeling, cannot be applied for the prophylactic treatment of heterotopic bone formation.

Animals↗
PubMed1992

Buprenorphine: an alternative to methadone for heroin dependence treatment.

Eighty-five heroin addicts who were unwilling to receive methadone maintenance or enter therapeutic communities were assessed, single-blind, for the lowest sublingual dose of buprenorphine that blocked heroin craving (8.0 mg max). All doses were administered daily under observation. After maintenance for 4 to 12 weeks, abstinent subjects (confirmed by urine drug screens) entered a double-blind discontinuation trial and were randomly assigned to receive dose reductions (10% twice weekly for 5 weeks to zero dose, then placebo for 2 weeks) or a stable dose for 7 weeks. Subjects were terminated from discontinuation if heroin was used or they had increased craving/symptoms. Subjects completed the trial if they did not use heroin and had no increase in craving/symptoms. A wide dose range (1.5-8.0 mg/day) was effective in reducing heroin craving and use. Of 73 subjects who received buprenorphine for 4 to 52 weeks, 40 had no prior treatment, despite high levels (mean $/day heroin = 70.5 +/- 94.7) and many years (mean years = 10.7 +/- 8.6) of dependence. Subjects who received dose reductions developed abstinence symptoms, low energy most commonly, associated with drug-seeking behavior. Discontinuation trial outcome (n = 51) shows a highly significant difference between 29 subjects who received dose reductions (28 terminated, 1 completed) and 22 subjects who received no dose reductions (3 terminated; 19 completed) (chi-square = 36.08; p less than .00001). The findings suggest that buprenorphine could be an important medication for reducing demand for heroin by many heroin addicts who remain outside the present health-care system.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Buprenorphine responders: a diagnostic subgroup of heroin addicts?

1. A 26-32 month follow-up of 16 heroin-dependent subjects who entered a pilot trial of treatment with buprenorphine (a mixed agonist/antagonist) suggests that positive response to treatment may identify a subgroup of untreated addicts whose levels of psychosocial functioning are intermediate between those for whom methadone (a pure agonist) or naltrexone (a pure antagonist) would be indicated. 2. Buprenorphine's pharmacologic profile provides a missing link in available modalities for opiate dependence treatment, making it acceptable for many addicts who will not accept methadone maintenance treatment, join a residential therapeutic community, or be successful on naltrexone treatment. 3. Eight of the 16 ss were abstinent from heroin while receiving 0.6-3.9 mg/day buprenorphine and counseling. Responders (mean age 34 yrs) had been heroin dependent for a mean of 9.5 years (range 6-17 yrs), all were self-supporting, 4 lived with a non-addicted spouse, 5 had no prior treatment for addiction and 3 had prior naltrexone treatment, but had discontinued it and relapsed. Non-responders (mean age 30 yrs) had been heroin dependent for a mean of 7.4 yrs (range 2-19 yrs), 7 had no regular employment, all were single and 7 had no prior treatment for addiction. 4. Levels of psychosocial functioning (work, home, leisure) and global assessments of functioning were significantly higher for buprenorphine responders than non-responders (p less than .001 and p less than .01 respectively). 5. A new formulation of buprenorphine needs to be developed for addiction treatment, ideally consisting of 0.5 mg and 2.0 mg sublingual tablets.

Adult↗
PubMed1984

Clonidine hydrochloride detoxification from methadone treatment--the value of naltrexone aftercare.

Treatment outcomes were compared for 2 groups of subjects detoxified from methadone using clonidine. One group of 12 subjects was encouraged to continue in treatment with naltrexone, while the other 12 subjects did not have naltrexone treatment available. Results suggested that those subjects who had naltrexone available were more successful at completing the 10 day detoxification treatment and that the relapse rate at 30 days post-treatment was significantly reduced by naltrexone treatment.

Adult↗
PubMed1984

Methadone and naltrexone in the treatment of heroin dependence.

Over the past 20 years, methadone maintenance has been shown to be a safe, effective treatment for large numbers of heroin addicts. The majority of patients derive major benefits while in treatment, most measurably in the areas of decreased use of illicit opiates, diminished criminality, increased levels of employment and more stable interpersonal relationships. An advantage of methadone maintenance over other treatments is that it attracts and retains a relatively large segment of the addict population and is reasonably cost-effective. Naltrexone is well suited as a transitional treatment for individuals who have progressed using methadone maintenance. Patients completing a course of methadone maintenance should be encouraged to use naltrexone during the postmethadone period, when symptoms of protracted abstinence often lead them to reinitiate use of heroin. Those with stable family relationships, good jobs, minimal antisocial behavior, and low drug-craving before beginning a course of naltrexone appear to benefit most from the treatment. Rates of retention improve when naltrexone is used within a comprehensive rehabilitation program. Although addicted individuals are often stereotyped, they are, in fact, a heterogeneous group representing a range of psychopathologies and life situations. Thus, within any one facility, a variety of modalities should be available to allow treatment to be tailored to the individual. No single treatment is best for all patients, and, moreover, the preferred modality for any one individual may change over time as a result of progress in treatment or varying life circumstances. Multimodality programs that include methadone and naltrexone enable the maximal number of individuals to benefit from treatment.

Heroin Dependence↗
PubMed1984

Cocaine abuse and its treatment.

Increasing numbers of individuals with a diagnosis of cocaine abuse (DSM-III, 305.6) are seeking medical and psychiatric care. The majority of users inhale the drug in powdered form, as cocaine is rapidly absorbed by mucous membranes. The patterns of use resemble those for the use of alcohol and marijuana: recreational, intensified, circumstantial, and compulsive. When cocaine is taken intravenously or by freebasing, individuals are much more vulnerable to developing a compulsive pattern of use that could lead to an organic delusional syndrome. Cocaine causes systemic effects that are similar to those of amphetamine, but they have a much shorter duration of action. Blood pressure, heart rate, feelings of "pleasantness" and "stimulation" are increased, and hunger is decreased. Acute tolerance may develop over hours of continuous use, but it disappears after a short period of abstinence (overnight). In psychomotor testing, performance that is impaired by fatigue is restored to baseline levels. Users like cocaine because they feel more alert, energetic, sociable, and sensual. However, these positive feelings are commonly followed by anxiety, depression, irritability, fatigue, and craving more cocaine. Chronic intoxication is always associated with adverse psychosocial sequelae. Treatment initially must be directed toward the patient's stopping all use of cocaine, employing strategies such as contingency contracts, urinalysis, family intervention, the assignment of financial control to others, or hospitalization. Several psychopharmacologic agents are helpful as an adjunct to a comprehensive treatment plan. Overdoses of cocaine are treated by diazepam and propranolol. Antidepressant medications, both TCAs and MAOIs, often help relieve the symptoms of depression that emerge when chronic use of cocaine is discontinued. Classical and operant conditioning contribute to craving for the drug and opportunities to extinguish these factors are valuable in preventing relapse. Compulsive users often have an Axis II diagnosis of borderline or narcissistic personality disorder, which require long-term psychodynamic psychotherapy.

Antidepressive Agents↗
PubMed1983

Opiate withdrawal using lofexidine, a clonidine analogue with fewer side effects.

In an open clinical trial, lofexidine, an alpha-noradrenergic agonist similar to clonidine, was administered to 30 opiate-dependent outpatient volunteers following abrupt discontinuation of chronic methadone or levo-alpha acetylmethadol (LAAM). Lofexidine significantly reduced opiate withdrawal symptoms without the adverse sedative and hypotensive effects that limit the safety and usefulness of clonidine. Lofexidine might prove to be a safer and more effective nonopiate treatment for opiate withdrawal, especially for ambulatory outpatients; controlled studies are required to confirm this possibility.

Adult↗
PubMed1982

Outpatient opiate detoxification with clonidine.

The finding that clonidine has significant withdrawal-suppressing effects in opiate addicts has led to clinical testing of its utility as a non-opiate treatment for opiate detoxification. Our outpatient studies have shown that clonidine can be used safely and effectively to detoxify opiate-dependent patients without hospitalization. Because of sedative and hypotensive side effects as well as varying sensitivity to the drug, clonidine doses must be individualized according to each patient's blood pressure and symptoms. Clonidine seems best suited for clinical use as a transitional treatment between opiate dependence and naltrexone. Our 10-day outpatient clonidine detoxification procedure has been extremely effective in allowing patients abruptly to discontinue the use of opiates and stay opiate-free long enough to initiate naltrexone treatment. Clonidine's side effects of sedation and hypotension have limited its clinical usefulness, particularly with outpatients, suggesting that other alpha-2 noradrenergic agonists might be found to have similar antiwithdrawal efficacy but without clonidine's undesirable side effects. Initial outpatient testing of lofexidine, a structural analog of clonidine, indicates that this drug may be as effective as clonidine for opiate detoxification and might be more suitable for outpatient treatment if it is found to lack the sedative and hypotensive side effects sometimes found with clonidine.

Ambulatory Care↗