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Biomedical subjects

S J Mubarak

Publications and source records attributed to S J Mubarak.

At least 55 records · Page 3Linked to original sources

Experimental observations on the effects of leg lengthening by the Wagner Method.

A proximal tibial epiphysiodesis was successfully performed on the right hind legs of 23 young lambs, producing an average shortening of 12% of the total length of the tibia. A lengthener was attached to stainless steel pins which were then tapped into the shortened tibia prior to osteotomy. In 16 of the 23 animals it was possible to lengthen the shortened bone at a rate of 0.5 mm twice daily until the discrepancy was corrected. The gait was normal in most of the animals, all had full knee motion with no thigh atrophy, and 16 had limited hock (ankle) joint motion. Lengthening of the tibia by more than 11% consistently produced muscle changes in the leg and cartilage damage in the hock (ankle) joint. Any malalignment of the tibial fragments during lengthening intensified these changes.

Animals↗

Skeletal muscle necrosis in pressurized compartments associated with hemorrhagic hypotension.

Skeletal muscle necrosis is quantified using technetium-99m stannous pyrophosphate (99mTc-PYP) in pressurized muscle compartments after severe blood loss. Six dogs (15 to 20 kg) were anesthetized by pentobarbital sodium (25 mg/kg IV) and hemorrhaged to a hypotensive state. Left hind-leg muscle compartments were pressurized to a level of 20 mm Hg for 6 hours by infusing autologous plasma. Intracompartmental pressure was continuously monitored by the wick catheter. The right leg served as a control. Forty-eight hours following pressurization, 5 mCi of 99mTc-PYP were injected IV, and 3 hours later each dog was sacrificed and pressurized and control muscles were resected simultaneously, weighed, and counted for 99mTc-PYP uptake. Significant uptake appeared in muscle compartments pressurized for 6 hours at 20 mm Hg, indicating that 20 mm Hg in a hypotensive state produces a degree of necrosis as great as that produced by 40 to 50 mm Hg in a normotensive state. We conclude that an acute compartment syndrome occurs in a hypotensive individual at an intramuscular pressure level considerably less than the threshold pressure level in an individual with normal blood pressure.

Acute Disease↗

Intramuscular pressures with limb compression. Clarification of the pathogenesis of the drug-induced muscle-compartment syndrome.

To study muscle necrosis due to prolonged limb compression, we measured intramuscular pressure by inserting wick catheters into 10 volar forearms and 10 anterior tibial compartments of adult volunteers. We then placed the subjects in positions in which victims of drug overdose are commonly found. Intramuscular pressures in the area of direct compression on hard surfaces ranged from 26 to 240 mm Hg, and averaged 101 mm Hg. Most remarkable was a mean pressure of 180 mm Hg on compression of the forearm by the rib cage. These pressures are sufficient to cause muscle and capillary ischemia and necrosis by local obstruction of the circulation. This local injury by limb compression may produce edema sufficient to start compartment tamponade and consequent muscle-compartment and crush syndromes.

Adult↗

Volkmann's contracture in children: aetiology and prevention.

A review was conducted of the records of fifty-five children who were admitted to the Hospital for Sick Children in Toronto between 1955 and 1975 with a diagnosis of Volkmann's contracture in fifty-eight limbs. Ten patients had been transferred to this hospital with established ischaemia after Bryant's traction for a fractured femur; all had a very poor outcome. Thirteen other cases of Volkmann's contracture affecting the superficial posterior compartment had been treated with a fixed Thomas' splint and a Bradford frame after fractures of the femoral shaft. Supracondylar fractures of the elbow resulting in Volkmann's contracture frequently had both an arterial injury and a compartment syndrome. Most of the fifty-five children reviewed here had not had early appropriate treatment. For the past twenty-one years the frequency of Volkmann's contracture has not declined in spite of many published reports on the compartment syndrome, and the hazards of supracondylar fractures and of Bryant's traction.

Adolescent↗

Familial osteochondritis dissecans of the knee.

The autosomal dominant pattern of osteochondritis dissecans and association with mild dwarfism were observed during a study of 4 generations of one family. Twelve of 31 family members had proven osteochondritis dissecans and 8 others appeared to have or (now deceased) have had it; 10 of these 20 patients were of short stature (less than 5%). At the onset, children under 11 years of age had bilateral irregularities of ossification. Three of the 11 adolescents (13-19 years) had osteochondritis dissecans with development of the condition from irregularities of ossification that could be traced in the roentgenograph of one. Two of the 3 surviving adults now in their sixth or seventh decade have osteoarthritis (one moderate, one severe). The younger adults, now in the 20's and 40's, have minimal knee sysmptoms.

Adolescent↗

Rattlesnake bites: current concepts.

The management of snake bites once the patient reaches the hospital should be to obtain the necessary blood parameters (type and cross-matched blood, complete blood count, platelets, PT, PTT, fibrinogen and fibrin split products, electrolytes and calcium), to evaluate the fang marks and the neurovascular status of the involved extremity and to monitor systemic signs and symptoms. These steps are extensively described in the literature, and are commonly agreed upon. We then start intravenous antivenom, after appropriate skin testing for horse serum allergy, beginning with 4--5 vials (8--10 in children) over the initial 30--60 minutes and titrating to cessation of the progression of the toxic signs. Concomitantly, we measure intracompartmental and subcutaneous tissue pressure in all clinically suspected areas. If intracompartment pressures are less than 30 mm Hg, surgical intervention is not necessary; antivenom is continued as necessary and the wick catheter measurements are repeated if indicated. If pressures are greater than 30 mm Hg,immediate surgical decompression is advisable.

Adult↗

Fluid balance within the canine anterolateral compartment and its relationship to compartment syndromes.

Fluid homeostasis within muscle compartments is maintained by four pressures: capillary blood pressure, capillary blood oncotic pressure, tissue-fluid pressure, and tissue fluid oncotic pressure. As determined in the canine anterolateral compartment, capillary blood pressure is 25 +/- 3 millimeters of mercury; capillary blood oncotic pressure, 26 +/- 3 millimeters of mercury, tissue-pbessure, -2 +/- 2 millimeters of mercury; and tissue-fluid oncotic pressure, 11 +/- 1 millimeters of mercury. The wick technique allows direct measurement of tissue-fluid pressure in skeletal muscle and, with minor modifications, is adapted to collect microsamples of interstitial fluid for determinations of tissue-fluid oncotic pressure. The wick technique detects very slight fluctuations in intracompartmental pressure such as light finger compression, injection of small volumes of fluid, and even pulsation due to adjacent arterial pressure. Adjacent muscle compartments may contain different tissue-fluid pressure due to impermeable osseofascial barriers. Our results obtained in canine muscle compartments pressurized by infusion of autologous plasma suggest that risks of muscle damage are significant at intracompartmental pressures greater than thirty millimeters of mercury.

Animals↗

Gluteal compartment syndromes: a report of three cases and management utilizing the Wick catheter.

Contusion or prolonged compression of the buttock produced severe local injury in 3 cases. Rhabdomyolysis with acute renal failure occurred in 2 of these cases, and one of them had an associated sciatic nerve palsy. The affected muscles included the gluteus maximus, gluteus medius, and the tensor fascia latae. Clinically and experimentally, these muscles were shown to be functionally enclosed within separate compartments like the peripheral limb muscles. Prompt decompression in the two cases with pressures exceeding 30 mm Hg resulted in muscle and nerve recovery.

Acute Kidney Injury↗

Acute compartment syndromes: diagnosis and treatment with the aid of the wick catheter.

Intracompartmental pressures were measured by the wick catheter technique in sixty-five compartments of twenty-seven patients who were clinically suspected of having acute compartment syndromes. A pressure of thirty millimeters of mercury or more was used as an indication for decompressive fasciotomy. The range of normal pressure was from zero to eight millimeters of mercury. Eleven of these patients were diagnosed as actually having compartment syndromes and in these patients, twenty-seven compartments were decompressed. Only two patients had significant sequelae. In the sixteen patients (thirty-eight compartments) whose pressures remained less than thirty millimeters of mercury, fasciotomy was withheld and compartment syndrome sequelae did not develop in any patient. Intraoperatively the wick catheter was used continuously in eight patients to document the effectiveness of decompression. Fasciotomy consistently restored pressures to normal except in the buttock and deltoid compartments, where epimysiotomy was required to supplement the fasciotomy. Continuous intraoperative monitoring of pressure by the wick catheter technique allowed us to select the few cases in which primary closure of wounds was appropriate and to decide which patients were best treated with secondary closure.

Adolescent↗

Double-incision fasciotomy of the leg for decompression in compartment syndromes.

Surgical decompression remains the only effective treatment for the ischemia of the muscles and nerves of the leg that constitutes the principal defects in the compartment syndromes. Recently, partial fibulectomy has been proposed as a good way to decompress all four compartments instead of the older double incision. Both methods are effective in satisfactorily reducing intracompartmental pressures, as documented by our wick catheter measurements. However, the double-incision technique is easier, faster, safer, and is the treatment of choice when four-compartment decompressive fasciotomy is indicated.

Compartment Syndromes↗

The wick catheter technique for measurement of intramuscular pressure. A new research and clinical tool.

The wick catheter technique was developed in 1968 for measurement of subcutaneous pressure and has been modified for easy intramuscular insertion and continuous recording of interstitial fluid pressure in animals and humans. Studies in dogs of the anterolateral compartment of the leg in simulation of the compartment syndrome showed the technique to be accurate and reproducible. The wick catheter technique is capable of important clinical applications in the diagnosis and treatment of acute and chronic compartment syndromes.

Animals↗

Genu valgum in children with coxa vara resulting from hip disease.

Three patients with chronic hip disease and progressive coxa vera deformity also had an unrecognized compensatory ipsilateral genu valgum until the primary hip deformity had been corrected operatively. This unrecognized genu valgum may become subtly worse in a growing child because of lateralization of the mechanical axis of the lower extremity with respect to the knee joint. Operative correction of coxa vara acutely moves the mechanical axis farther laterally, causing the occult genu valgum to become clinically apparent. The genu valgum may subtly worsen over time in a growing child because of lateralization of the lower extremity mechanical axis with respect to the knee joint, with the resulting abnormal Hueter-Volkmann forces across the physis causing progressive genu valgum. Recognition of occult genu valgum before correcting coxa vara in children allows the surgeon the better to advise the family about the need for possible subsequent operations on the knee.

Adolescent↗