Biomedical subjects

R G Alvarez

Publications and source records attributed to R G Alvarez.

13 recordsLinked to original sources

PubMed2001

Shock wave therapy (Orthotripsy) in musculoskeletal disorders.

Extracorporeal shock wave therapy, which now is used routinely for urolithiasis, has gained increasing acceptance in Europe for some musculoskeletal problems and has led to the inception of clinical studies in the United States. The authors have reviewed the available literature to assess the biologic effects of shock waves on human musculoskeletal tissues, the credibility of published studies on therapeutic applications, and the potential for more widespread application of this modality to various skeletal and near-skeletal disorders. The primary advantage of extracorporeal shock wave therapy is its noninvasive nature and seemingly minimal complications when applied to musculoskeletal tissues.

High-Energy Shock Waves↗

PubMed2000

Tibiocalcaneal arthrodesis for the management of severe ankle and hindfoot deformities.

PURPOSE: The purpose of this investigation was to evaluate the outcome of tibiocalcaneal arthrodesis using an adolescent condylar blade plate for severe ankle and hindfoot deformities. MATERIALS AND METHODS: We retrospectively reviewed the records of patients managed at our institutions between 1989 and 1996 whose tibiocalcaneal arthrodeses were performed with adolescent condylar blade plates and allograft bone. In these 30 patients (14 men, 16 women; average age, 53 years), the etiologies of the nonbraceable deformity included: diabetic neuroarthropathy with talar fragmentation and resorption (26), inflammatory arthritis (3), and posttraumatic avascular necrosis of the talus with collapse (1). Due to the severity of the deformity in 28 of these patients, the alternative treatment would have been amputation. Thirteen patients had undergone previous surgeries, eight had documented osteomyelitis, and 13 had ulcers ranging from 2 to 27 mm. At surgery, the remnants of the talus were removed. Morcellized bone graft mixed with tobramycin/vancomycin powder was inserted into the arthrodesis site and then fixed with a rigid plate. Intravenous antibiotics, followed by oral antibiotics, were given until wound healing and suture removal. Follow-up averaged 48 months (19 to 112 months). RESULTS: Tibiocalcaneal fusion was achieved in 28/30 patients at an average of 16 weeks (12 to 18 weeks). Complications occurred in seven patients: two developed stress fractures of the tibia at the proximal end of the blade plate, three had superficial cellulitis that resolved with antibiotic therapy, and two had nonunions. CONCLUSION: Tibiocalcaneal arthrodesis using an adolescent condylar blade plate and allograft bone can be a successful procedure in the patient with severe neuropathic ankle deformity and can achieve a stable plantigrade foot for limited community ambulation with relatively few complications.

Adult↗

PubMed1998

Thromboembolism after foot and ankle surgery. A multicenter study.

Thromboembolic disease presents a potentially fatal complication to patients undergoing orthopaedic surgery. Although the incidence after hip and knee surgery has been studied and documented, its incidence after surgery of the foot and ankle is unknown. For this reason, a prospective multicenter study was undertaken to identify patients with clinically evident thromboembolic disease to evaluate potential risk factors. Two thousand seven hundred thirty-three patients were evaluated for preoperative risk factors and postoperative thromboembolic events. There were six clinically significant thromboembolic events, including four nonfatal pulmonary emboli, after foot and ankle surgery. The incidence of deep vein thrombosis was six of 2733 (0.22%) and that of nonfatal pulmonary emboli was four of 2733 (0.15%). Factors found to correlate with an increased incidence of deep vein thrombosis were nonweightbearing status and immobilization after surgery. On the basis of these results, routine prophylaxis for thromboembolic disease after foot and ankle surgery probably is not warranted.

Adolescent↗

PubMed1995

Controversies in treating talus fractures.

Controversies of talus fractures are related to the rare incidence of these fractures and the even more sparse, clinically based, objective research examining treatment outcomes. This article outlines various talus fracture types, treatment, and treatment controversies. A discussion section summarizing treatment controversies of talar neck fractures, the most common talus fracture, is also included.

Adult↗

PubMed1994

Rattlesnake bite complications in 19 children.

The Western diamondback rattlesnake, Crotalus atrox, is responsible for the majority of snakebites in Sonora, Mexico. We report 19 cases of children who were attacked by these snakes. Most of the rattlesnake attacks occurred in rural areas during the summer. The children's ages ranged from one to 15 years. The lower extremities, especially the legs, were most often bitten. The signs and symptoms presented by these patients included: pain, edema, limitation of motion, ecchymosis, bleeding and necrosis in the area of the bite, epistaxis, hematuria, and vomiting. Hospital treatment included: parenteral electrolyte solutions, antivenom serum, antibiotics, tetanus toxoid, blood transfusions, hydrocortisone, heparin, and peritoneal dialysis. In one case a fasciotomy was necessary. The observed complications on envenomations included: hemolysis, local necrosis, coagulation disorders, paresthesia, somnolence, and acute renal failure. One death occurred from disseminated intravascular coagulation.

Adolescent↗

PubMed1994

Tibiocalcaneal arthrodesis for nonbraceable neuropathic ankle deformity.

Seven patients with nonbraceable, neuropathic ankle joints have been successfully treated by tibiocalcaneal arthrodesis utilizing an adolescent condylar blade plate, large cannulated AO screws, and a special cancellous allograft mixture. All patients had fragmentation and partial resorption of the talus. This procedure was considered as an alternative to below-knee amputation. Goals were limb salvage and limited community ambulation. Criteria for proceeding with the fusion were a commitment by the patient to 6 to 8 months of nonweightbearing ambulation, a biopsy and culture of the talus revealing no evidence of infection, and a nonbraceable deformity of the foot and ankle that would otherwise require amputation. A toe-level Doppler index or a transcutaneous oxygen index of greater than 0.45 was required. All patients were treated initially in a total contact cast or bivalved total contact ankle-foot orthosis (AFO) until wounds and swelling were controlled and there was no erythema. Presence of an ulcer did not preclude surgery. The arthrodesis used a combination of 7.0-mm AO cannulated screws and an adolescent condylar blade plate. A special preparation of fresh-frozen, irradiated, cancellous allograft mixed with tobramycin and vancomycin powder was used. All ankles fused solidly in an average of 5.2 months. No infectious complications were encountered. Two patients developed a stress fracture of the tibia at the proximal aspect of the blade plate before use of a bivalved AFO. These healed with nonoperative treatment in 6 weeks. All patients were satisfied with their result at their latest follow-up (average 26.9 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Ankle Joint↗

PubMed1987

Occurrence of the plantaris tendon in patients sustaining subcutaneous rupture of the Achilles tendon.

Many surgeons treat closed subcutaneous rupture of the Achilles tendon with primary surgical repair. Reinforcement of the primary repair can be accomplished easily using the plantaris tendon. Unfortunately, in the population of patients who sustain this injury, the plantaris is absent in 60% of patients. This is a statistically significant difference when compared to the absence of the plantaris tendon of less than 10% in reported cadaveric studies.

Achilles Tendon↗

PubMed1983

Further studies on the effects of ketotifen on guinea pig ileum.

Ketotifen (Ke) at the concentration of 10(-5) M or greater significantly inhibits guinea pig ileum contractions induced by cumulative dose response curves to Pg alpha F2 or BaCl2. This inhibitory effect of Ke is also observable against ileal contractions induced by isotonic and hypertonic solutions with high K+ and by electrical stimulation. In contrast to the long term antihistaminic effect of DSCG and Ke, the latter drug exhibits a shorter inhibitory effect when Ach and electrical stimulation are used to induce ileal contractions shortly after Ke is removed by washing from the organ bath. This nonspecific protective effect of Ke on smooth muscle against various spasmogens resembles the one reported recently by us for DSCG and might be relevant to the antiallergic and antiasthmatic properties of both drugs.

Acetylcholine↗

PubMed1982

Further studies on the effects of disodium cromoglycate on guinea pig ileum.

Transmural electrical stimulation was carried out on innervated strips of the longitudinal muscle of guinea pig ileum. Disodium cromoglycate (DSCG) inhibited the electrically induced contractions. Five minutes later, prostaglandin E2 (2.5 ng/ml) was added to the bath and it reversed the action of DSCG. Furthermore, DSCG inhibits significantly the guinea pig ileum contractions induced by nicotine and also those induced by histamine and acetylcholine on ileum denervated by cooling. These results suggest that DSCG effects on guinea pig ileum contraction are mediated by membrane-stabilizing properties of this drug on smooth muscle fibres as well as on myenteric plexus.

Animals↗

PubMed1981

Ascorbic acid and pyridoxine in experimental anaphylaxis.

Two vitamins, ascorbic acid (AA) and pyridoxine have been suggested by others as useful drugs for the treatment of bronchial asthma, although the views concerning AA or controversial. We have tested both vitamins in some models of histamine release and experimental anaphylaxis. AA does not inhibit mast cell degranulation induced by phospholipase A and histamine release from isolated rat mast cells induced by compound 48/80 or antigen (egg albumin). On the contrary, in the latter tests pyridoxine exerts inhibition in a range of concentrations from 10(-3)-10(-2) M. We conclude: 1. There is no experimental basis for considering ascorbic acid as a prophylactic antiasthmatic drug as is disodium cromoglycate. 2. Pyridoxine must receive additional basic and clinical investigations in this field.

Anaphylaxis↗

PubMed1981

New light on the mechanism of action of disodium cromoglycate.

Disodium cromoglycate (DSCG) shows a prolonged protective effect against histamine on the smooth muscle of guinea pig ileum. Preventing allergen-induced mediator release from mast cells as well as protection of smooth muscle against mediators already released can both explain a beneficial effect of DSCG in the treatment of bronchial asthma and food allergy. It is believed that disappointing clinical trials with many new anti-allergic drugs, e.g. RS 7540, can be explained by the lack of protective effect on the smooth muscle of target organs.

Animals↗

PubMed1980

Effect of some membrane stabilizing drugs on histamine-induced contraction of guinea pig ileum.

The effect of disodium cromoglycate (DSCG), pyridoxine and procaine on histamine-induced contraction of isolated guinea pig ileum was investigated. The antiallergic drug DSCG exerted a protective action on ileum against histamine either when it was present or after it was washed out. Procaine, a local anesthetic exerted a similar pharmacological action on ileum to that of DSCG. On the other hand, pyridoxine protected guinea pig ileum against histamine only when it was present in the bath and this effect quickly disappeared after removing of pyridoxine. The mechanism of action of both DSCG and procaine is discussed in relation to their membrane stabilizing effect and inhibition of calcium transport, whereas effect of pyridoxine resembled to some extent, the action of theophylline.

Animals↗

PubMedDate not supplied

Lateral roentgenographic projections of the acromioclavicular joint.

Although the acromioclavicular joint is frequently injured in both contact and noncontact sports, the treatment is nonspecific, as demonstrated by the numerous methods of treatment currently employed. Despite treatment, some shoulders still develop chronic symptoms and disability during overhead lifting, throwing, and swinging. Perhaps these difficulties develop as a result of an incomplete evaluation of the joint and because the exact nature of the injury is not appreciated. Therefore, the shoulder develops chronic problems. We have routinely utilized a lateral roentgenogram of the acromion to evaluate the acromioclavicular joint. This has significantly aided us in the diagnosis and treatment of acromioclavicular joint injuries, especially when there was posterior dislocation of the distal clavicle. This presentation reviews standard roentgenography of the acromioclavicular joint and illustrates the method of obtaining the lateral projection as described by O. M. Alexander. We will also show how this method has helped us clinically in detecting posterior dislocations of the distal end of the clavicle.

Accidents, Traffic↗