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Biomedical subjects

S J Mubarak

Publications and source records attributed to S J Mubarak.

At least 37 records · Page 2Linked to original sources

Fracture of the tibia complicated by acute compartment syndrome.

A consecutive series of 32 patients with tibia fractures complicated by compartment syndrome was treated with fasciotomy. One group was also treated with closed reduction of the fracture and cast immobilization and compared with a comparable group treated with internal fixation without case immobilization after fasciotomy. All other patients were treated with fasciotomy and reduction followed with either external skeletal fixation, pins and plaster, or skeletal traction. Care of the open fasciotomy incisions, observation of the neurovascular status of the limb, and rehabilitation of the extremity were facilitated by internal fixation operations without subsequent external cast immobilization. The anatomic and functional results in this group were better than those treated with fasciotomy and cast immobilization. All fractures were united by 20 weeks. Complications in both groups were similar, although one deep infection, which was resolved with appropriate treatment, occurred in the group treated with internal fixation. Six open tibia fractures were treated with external skeletal fixation after fasciotomy; the results were less satisfactory, but the initial injuries were also more severe in this group. Patients with closed tibial fractures complicated by compartment syndromes should be treated expeditiously with fasciotomy, followed by stable internal fixation.

Acute Disease↗

Vibratory response in idiopathic scoliosis.

Recent clinical studies have suggested that a neurological lesion may be a cause of adolescent idiopathic scoliosis and animal experiments have implicated the posterior column pathway. We have tried to determine if differences in neurological response could be detected and measured clinically, and have compared the threshold of detection of vibratory sensation in 20 girls with adolescent idiopathic scoliosis with that in 20 clinically normal age-matched controls. A highly significant reduction of the threshold of detection of vibration was seen in the scoliotic group compared to the controls (p less than 0.001). Curve magnitude did not correlate with this threshold for either the upper (r = 0.172) or lower extremity (r = 0.126). Significant asymmetry between right- and left-sided thresholds to vibration was demonstrated in the scoliotic group. Our study supports the concept that an aberration in the function of the posterior column pathway of the cord may be of primary importance in the aetiology of idiopathic scoliosis. A clinically practical test to measure this function is presented.

Adolescent↗

Carpenter syndrome: natural history and clinical spectrum.

Recently, we evaluated three sibs with Carpenter syndrome, permitting further clinical, orthopedic, radiographic, and psychometric delineation of this disorder. All three patients were operated on for craniostenosis at or before 2 months. Although all had gross motor delay in early infancy, two had normal intelligence at 12 months and 10 years, respectively. Bony abnormalities contributed to functional impairment especially in the older children. Preaxial polydactyly of feet was present in all three affected sibs and in all other reported individuals with this condition, allowing differentiation of Carpenter syndrome from the other autosomal-recessive acrocephalopolysyndactyly syndromes.

Adolescent↗

The effect of antivenin on intramuscular pressure elevations induced by rattlesnake venom.

The dose of an antivenin required to neutralize a clinical case of venom poisoning, as well as determining the timing or need to initiate antivenin treatment, is frequently difficult to objectively ascertain. In this study, venom from the southern Pacific rattlesnake, Crotalus viridis helleri, was injected into 29 dog hind limb anterolateral compartments. A solution of C. v. helleri venom (15 mg/ml) was prepared using dessicated venom and saline; 0.2 ml were injected sub-fascially so that each of the compartments received 3 mg of venom. In one group no antivenin was given, in a second group four vials of antivenin were administered i.v. 1 hr post-injection, and in the final group eight vials of antivenin were administered i.v. 1 hr following venom injection. In all groups intracompartment pressures, limb girth and surface temperature were measured at regular intervals over the first 48 hr. In the group receiving eight vials of antivenin the intracompartment pressure reached a peak mean pressure of 49 mm Hg at 2 - 4 hr, and then rapidly fell. In those treated with none or four vials the pressure rose to 70 and 60 mm Hg, respectively, and remained elevated over the first 24 hr. The difference between the former and latter two groups is statistically significant. The findings indicate that the intracompartmental pressure, and presumably destructive damage of the venom, can be controlled by adequate levels of i.v. antivenin. Intracompartmental pressure measurements should be considered as an adjunct in the monitoring and decision-making processes for the treatment of patients bitten by rattlesnakes.

Animals↗

Rattlesnake bites and surgical decompression: results using a laboratory model.

Studies were performed on the hind limbs of dogs and their anterolateral compartments to evaluate the effect of fasciotomy on tissue pressure and necrosis following pit viper envenomation. Venom from the southern Pacific rattlesnake, Crotalus viridis helleri, was injected into either the subcutaneous tissues, the intact anterolateral compartment or the anterolateral compartment following fasciectomy. Interstitial fluid pressure measurements, as well as limb girth and surface temperatures, were obtained over the first 48 hr following venom injection, after which time the compartment contents were examined microscopically. The results demonstrated intracompartment tissue pressure elevations only following intracompartment injections. Fasciectomy prior to injection did not prevent muscle necrosis, though it did reduce maximum compartment pressures. Clinically the limbs in each group could not be differentiated. Intracompartment pressure measurements were able to distinguish between muscle and subcutaneous envenomations by the differences in compartment pressures. These results demonstrate the value of tissue pressure measurements in the evaluation of patients envenomated by rattlesnakes. They also indicate the objectivity necessary to determine the need for surgical decompression.

Animals↗

Hereditary tendo Achillis contractures.

A study was performed on eight patients with tendo Achillis contractures. Family histories were obtained and a short regimen of casting was performed. Hereditary tendo Achillis contracture is an autosomal dominant condition with variable expression. It is a relatively benign condition that is both a cosmetic and functional problem for the patient. The disorder responds well to a short course of casting. Follow-up exercises are necessary to maintain normal ankle motion and heel strike during gait. Operative treatment was not necessary in these patients.

Achilles Tendon↗

Correlation of scoliosis and pulmonary function in Duchenne muscular dystrophy.

Pulmonary function was correlated with patient age and degree of thoracic scoliosis in 25 patients with Duchenne muscular dystrophy in a retrospective, longitudinal study. The observed forced vital capacity (FVC) was found to peak at approximately the age when standing ceases, then to decline rapidly. Thoracolumbar curves were found to be insignificant in adversely affecting pulmonary function in patients with Duchenne muscular dystrophy. Percent FVC was found to be the parameter of pulmonary function that was most strongly correlated with age and scoliosis measurements. In addition, age and thoracic scoliosis together were better predictors of percent FVC than either one alone. Each 1 year of age had approximately the same negative influence on percent FVC that each 10 degrees of thoracic scoliosis had; both decreased percent FVC by approximately 4%. A regression equation for percent FVC is presented which predicts that the patient who has had scoliosis progression halted by spinal fusion would, subsequent to the surgery, show a slower rate of decline of percent FVC and that this rate is quantifiable, predictable, and dependent solely on the patient's advancing age. Therefore, early spinal instrumentation and fusion is advocated in the patient with Duchenne muscular dystrophy.

Adolescent↗

Fluid shifts and muscle function in humans during acute simulated weightlessness.

Head-down tilt is considered an effective experimental model to simulate weightlessness. To determine the acute effects of simulated weightlessness on transcapillary fluid balance, tissue fluid shifts, muscle function, and triceps surae reflex time, eight supine subjects were tilted 5 degrees head down for 8 h. A cephalic fluid shift from the legs was indicated by facial edema, nasal congestion, increased urine flow, decreased creatinine excretion, reduced calf girth, and decreased lower leg volume. As measured by wick catheters inserted under local anesthesia, interstitial fluid pressure in the tibialis anterior muscle (4.6 +/- 0.6 mmHg) and subcutaneous tissue (0.6 +/- 0.5 mmHg) of the lower leg fell significantly to -2.8 +/- 0.5 and -3.8 +/- 0.4 mmHg, respectively. Other transcapillary pressures (capillary and interstitial fluid colloid osmotic pressures) were relatively unchanged. Needle-biopsy specimens, obtained just before and after tilt, indicated that total water content of soleus muscle was unchanged during 8 h of head-down tilt. After head-down tilt, isometric strength and isokinetic strength of the plantar flexors were unchanged. Triceps surae reflex time associated with plantar flexion movement slowed slightly after the tilt maneuver. Collectively these results demonstrated a dehydration effect of head-down tilt on muscle and subcutaneous tissues of the lower leg that may affect muscle function.

Adult↗

A practical approach to compartmental syndromes. Part II. Diagnosis.

The earliest manifestation of a compartment syndrome is elevated intracompartmental pressure. Over a relatively short period of time this increased pressure and ischemia can cause permanent injury to the contents of the compartment if left untreated. To achieve early diagnosis and treatment of a compartment syndrome, recognition of the clinical findings and measurement of intracompartmental pressure must be expeditious.

Catheterization↗

Ultrasound evaluation of the anterior musculofascial compartment of the leg following exercise.

An ultrasonic method is described to measure changes in width of the anterolateral leg compartment in its lower third following exercise. In 20 normal subjects, compartment widths increased an average of 8.6% following exercise, with joggers' compartments increasing 10.1%, as compared to 7.4% in nonjoggers. Control measurements of the compartment width in a cadaver leg showed excellent correlation with the ultrasound measurement. Following exercise, vascular responses and fluid transfers caused an increase in volume of the compartment contents, which is reflected in compartment widening. Because the compartment contents are usually contained by a complete but only moderately compliant wall, intracompartmental pressure will normally rise, and symptoms of a compartment syndrome will result. Diagnosis of exertional compartment syndrome in the leg has usually been made at clinical examination. Measurement of compartment width increase is intended to complement intracompartmental pressure and aid in differentiating the diagnosis of exertional compartment syndrome from shin splints, stress fracture, and tendonitis. Additionally, muscle atrophy, hypertrophy and growth can be recorded by the ultrasound technique.

Adult↗

Role of fascia in maintenance of muscle tension and pressure.

The effect of fasciotomy on muscle tension (measured by a force transducer attached to the tendon) and interstitial fluid pressure (measured by Wick catheters in the muscle belly) was studied in the anterolateral compartments of 13 dog hindlimbs. Muscle tension and pressure were monitored in the tibialis cranialis muscle after low- and high-frequency stimulation of the peroneal nerve to produce twitch- and tetanic-type contractions. Fasciotomy decreased muscle force during the low-frequency stimulation by 16% (35.3 +/- 4.9 to 28.4 +/- 3.9 N) and during the high-frequency stimulation by 10% (60.8 %/- 4.9 to 54.8 +/- 3.9 N). Muscle pressure decreased 50% after fasciotomy under both conditions, 15 +/- 2 to 6 +/- 1 mmHg and 84 +/- 17 to 41 +/- 8 mmHg), respectively. Repeated functional evaluations during the testing procedure indicated that muscle fatigue was not a major factor in these results. It was concluded that fascia is important in the development of muscle tension and changes in interstitial pressure. Furthermore, the results raised questions concerning the merits of performing a fasciotomy for athletes with a compartment syndrome.

Animals↗

Juvenile osteochondritis dissecans of the knee: etiology.

Of 73 patients in whom 122 lesions of osteochondritis dissecans of the knee developed, nearly half had multiple lesions and 30% were of short stature. Endogenous and exogenous traumas play a minor role in the etiology of this disorder. Over half of the children with a history of trauma had bilateral and symmetrical lesions. Constitutional factors, such as hereditary predisposition, endocrine dysfunction, collagen and epiphyseal abnormalities, are frequently associated with juvenile osteochondritis dissecans of the knee.

Adolescent↗

Quantification of intracompartmental pressure and volume under plaster casts.

UNLABELLED: Infusion lines (to elevate intracompartmental pressure experimentally) and wick catheters (to monitor the pressure produced) were inserted into hind-limb muscle compartments in twenty-six dogs. A padded plaster cast was then applied. The effect of the cast on intracompartmental pressure and volume and the effect of first splitting the cast and then cutting the padding were determined. Three different padding were used: dry Webril, Webril soaked in blood and Betadine (povidone-iodine), and Webril soaked in blood and Betadine and then dried. The cast was found to restrict expansion of the compartment volume by approximately 40 per cent. The most significant reductions in pressure in all groups occurred after the cast was cut and spread (mean reduction, 65 per cent). An additional pressure reduction of 10 to 20 per cent occurred after cutting the Webril. After removal of the cast, all limbs maintained some residual elevation of the intracompartmental pressure. CLINICAL RELEVANCE: This study demonstrates the need in clinical practice for continued evaluation and monitoring of a limb even after the cast has been completely removed because of signs and symptoms of a compartmental syndrome.

Animals↗

Quantitation of skeletal-muscle necrosis in a model compartment syndrome.

UNLABELLED: Skeletal-muscle necrosis was evaluated in previously pressurized canine compartments using technetium-99m stannous pyrophosphate and classic histological criteria. Intracompartmental necrosis was quantitated in the anterolateral muscle compartment of each dog by uptake of 99mTc stannous pyrophosphate using the contralateral anterolateral compartment as an internal control. Representative specimens of muscle were sampled in experimental and control legs of each dog and were analyzed by qualitative histological techniques. Muscle necrosis was assessed in compartments forty-eight hours after pressurization to levels of ten to 120 millimeters of mercury for eight hours in thirty-seven dogs. In another dog, neither anterolateral compartment was pressurized so that both compartments acted as control muscle. The results in these experiments identify a threshold pressure level (thirty millimeters of mercury) and duration (eight hours) at which significant muscle necrosis occurs at normal blood pressure. Our findings imply that a quantitative relationship exists between incorporation of 99mTc stannous pyrophosphate and the level of intracompartmental pressure. This uptake technique, however, is not suitable for diagnosing compartment syndrome in patients with a threatened compartment syndrome. We suggest that intracompartmental pressure measurements by the wick-catheter technique, in conjunction with clinical findings, offer the best means for diagnosing compartment syndrome. CLINICAL RELEVANCE: Significant muscle necrosis associated with an impending compartment syndrome occurs at a threshold intracompartmental pressure of thirty millimeters of mercury after eight hours. Since time variables are often unknown in suspected compartment syndromes, fasciotomy is recommended when intracompartmental pressure exceeds thirty millimeters of mercury in a patient with normal blood pressure. The use of this threshold pressure level as an indication for fasciotomy requires a device for measuring intracompartmental pressure such as the wick catheter.

Animals↗

The acute carpal tunnel syndrome.

Acute carpal tunnel syndrome occurred subsequent to fractures of the wrist in four patients. A bone graft operation had been performed on the distal end of the radius in a fifth patient. Each patient underwent a normal neurologic examination immediately posttrauma; only one experienced early return of nerve function. Four patients were treated by carpal tunnel release at 36 to 96 hours after the injury. Carpal canal pressure measurements were performed pre- and postoperatively in one patient.

Acute Disease↗