Robert L. Sufit

Chronic compartment syndrome: Diagnosis, management, and outcomes

A consecutive operative series of 100 patients with chronic compartment syndrome involving 233 compart ments is reported. Seven of every eight were athletes, and runners predominated. Exercise-induced symp toms of consistently recurring tightness, aching (in some, sharp pains) in anatomically defined compart ments were pathognomonic. Mean months of symp toms prior to operation was 22; median age was 26 years. Bilaterality occurred in 82. The distribution of compartments was: anterior, 39%; lateral, 12%; and posterior, 48%. Incidental compartment pressures were elevated (x = 23 mmHg). Fasciotomy using local anesthesia was performed on 70 outpatients. At a median of 4.5 months, over 90% were cured or signifi cantly improved in symptoms and/or function. Median time to walking unassisted was 2 days, and to resump tion of conditioned running 21 days. Fasciotomy can be a safe, effective, and economical treatment for chronic compartment syndrome.

The effect of pedaling frequency on glycogen depletion rates in type I and type II quadriceps muscle fibers during submaximal cycling exercise

SummaryThis study was conducted to determine whether the pedaling frequency of cycling at a constant metabolic cost contributes to the pattern of fiber-type glycogen depletion. On 2 separate days, eight men cycled for 30 min at approximately 85% of individual aerobic capacity at pedaling frequencies of either 50 or 100 rev·min−1. Muscle biopsy samples (vastus lateralis) were taken immediately prior to and after exercise. Individual fibers were classified as type I (slow twitch), or type II (fast twitch), using a myosin adenosine triphosphatase stain, and their glycogen content immediately prior to and after exercise quantified via microphotometry of periodic acid-Schiff stain. The 30-min exercise bout resulted in a 46% decrease in the mean optical density (D) of type I fibers during the 50 rev·min−1 condition [0.52 (0.07) to 0.28 (0.04)D units; mean (SEM)] which was not different (P>0.05) from the 35% decrease during the 100 rev · min−1 condition [0.48 (0.04) to 0.31 (0.05)D units]. In contrast, the meanD in type II fibers decreased 49% during the 50 rev·min−1 condition [0.53 (0.06) to 0.27 (0.04) units]. This decrease was greater (P<0.05) than the 33% decrease observed in the 100 rev·min −1 condition [0.48 (0.04) to 0.32 (0.06) units). In conclusion, cycling at the same metabolic cost at 50 rather than 100 rev·min−1 results in greater type II fiber glycogen depletion. This is attributed to the increased muscle force required to meet the higher resistance per cycle at the lower pedal frequency. These data are consistent with the view that force development as opposed to velocity of contraction determines the degree of type II fiber recruitment when the metabolic cost of exercise is held constant.

Relationships between speech intelligibility and the slope of second-formant transitions in dysarthric subjects

The relationship between speech intelligibility on a single-word identification test and the average second-formant (F2) slope of selected test words was examined for a group of 25 men and ten women with amyotrophic lateral sclerosis (ALS). A Spearman rank-order correlation coefficient greater than 0.80 was obtained for both the male and female subjects. This moderately high correlation indicates that the F2 slope index is a useful acoustic measure of speech proficiency in ALS. F2 slope indices are reported for normal control populations of geriatric men and women. In addition, progressive deterioration of the F2 slope index is illustrated in a case study of one woman with ALS.

Physiologic and metabolic response to progressive and prolonged exercise in amyotrophic lateral sclerosis

Physical work capacity in 35 ALS patients and 6 untrained controls was evaluated during progressive bicycle ergometery. In the ALS patients, maximum oxygen consumption (VO2max) and work capacity (Wmax) drop in relation to the decrease in ALS functional score. However, the oxygen cost (ml O2/kpm) of submaximal exercise was significantly increased. Prolonged submaximal exercise tests in six ALS patients and six matched untrained controls indicated that the exercise-induced increase in plasma free fatty acids, beta-hydroxybuty-rate, esterified carnitine, and muscle esterified carnitine was significantly retarded in ALS patients.

A modification of the modified barium swallow

The ability of 64 patients and 7 normal adult subjects to swallow 2 cc (1/2 teaspoon) and 30 cc (gulp from cup) amounts of radiopaque liquid was tested. Bolus size had no influence on the swallowing ability of the normal subjects. However, six of the patients aspirated on the gulp but not on the teaspoon swallows, and three patients aspirated on the teaspoon swallows but not on the gulp. These findings support the need for continued experimental testing of the modified barium swallow protocol if its clinical utility is to be enhanced further.

Suramin‐induced weakness from hypophosphatemia and mitochondrial myopathy. Association of suramin with mitochondrial toxicity in humans

Background. Suramin is an antiparasitic drug being evaluated as an antitumor compound. Suramin therapy commonly causes weakness and is known to cause neuropathy. Two potential causes of suramin‐induced muscular weakness are described.

Visual evoked potential changes following renal transplantation

We have followed a group of 18 uremic patients through living-related donor renal transplantation (RTX) using pattern-reversal VEPs. Recordings were made prior to and 10 weeks after surgery at high, medium and low spatial frequencies. Prior to RTX, mean latency of the P100 component of the VEP was 107 msec. Individual values did not correlate with blood urea nitrogen or creatinine. Patients requiring hemodialysis did not differ from non-dialyzed patients. Ten weeks after RTX P100 latencies were significantly shortened while N75 latencies were unchanged. Several diabetic patients exhibited the appearance of previously unrecorded wave forms. P100 latency increased significantly with increasing spatial frequency before and after transplantation. Diabetic patients demonstrated a consistent increase in P100 amplitude while non-diabetic patients demonstrated a consistent decrease in P100 amplitude after RTX. The data indicate that renal transplantation has beneficial effects on the central nervous system of uremic patients not seen with chronic hemodialysis and that these effects may be quantitatively measured using the VEP. The data further suggest that electrophysiological effects of uremia and diabetes may be additive, but reversible after RTX. Alterations in the uremic and diabetic VEP may be related to retinal or more proximal central nervous system structures.

DEFICIENCY OF MUSCLE CYTOCHROME C OXIDASE (CO) IN LEIGH'S DISEASE

A 3y/o male presented with a progressive neurologic disorder characterized by hypotonia, ophthalmoplegia and ataxia. Post-mortum studies at 4 1/2y revealed Leighs disease. Biochemical findings included elevation of blood lactate (L) (ranging from 1.9 to 7.0mM, normal mean ± SD 1.0±0.4mM), pyruvate (P) (0.11 to 0.25, normal 0.11±0.03mM) and L/P ratio (14 to 35, normal 10 to 18). β-OH-butyrate (BOH), acetoacetate and L were intermittently present in urine. Plasma amino acids were normal. CSF L (4.7mM) and P (0.24mM) were elevated. Increased urinary excretion of glycine and alanine was present. No increase in blood L or P was noted after IV glucose (100mg/kg). During an 18 hr fast blood BOH increased to 2000μM (normal 91±81μM, n=4) with little change in blood L, P, or glucose levels. Skeletal muscle biopsy (pre-mortum) showed absent CO on histochemical staining. Muscle mitochondria exhibited decreased rates of State 3 respiration; 47 natoms O2/min/mg protein with pyruvate/malate and 63 natoms O2/min/mg protein with succinate/rotenone (reported normal rates 147 and 158 natoms O2/min/mg protein, respectively). Muscle cytochrome spectrum obtained from the difference in absorption of reduced and oxidized forms revealed an absence of the 605 nM peak corresponding to CO. This case confirms the findings of Willems JL, et al (Ped 60:850, 1977) indicating that a subgroup of patients with Leighs encephalomyelopathy have CO deficiency.

Intermittent negative pressure ventilation in the treatment of respiratory failure in progressive neuromuscular disease

Five men with degenerative neuromuscular diseases (three with amyotrophic lateral sclerosis [ALS] and two with Duchennes muscular dystrophy [DMD]) who had respiratory failure were treated with intermittent negative pressure ventilation (NPV). One patient with ALS in severe acute respiratory failure was successfully treated with NPV alone. This patient and two other ALS patients in chronic respiratory failure with Paco2 elevation stabilized or improved their vital capacity (VC) and lowered their Paco2 after 5 to 11 weeks of therapy. Finally, intermittent NPV was used to replace 24-hour positive pressure ventilation in two patients with DMD. It is concluded that intermittent NPV may stabilize or temporarily improve the respiratory status in patients with progressive neuromuscular diseases.

Doxacurium and mivacurium do not trigger malignant hyperthermia in susceptible swine

The role of succinylcholine in the precipitation of malignant hyperthermia (MH) necessitates the testing of new neuro-muscular relaxants for their ability to trigger MH in MH-susceptible swine before general human use. We tested doxacurium and mivacurium, two new nondepolarizing bis-benzylisoquinolinium neuromuscular relaxants, at ED95 and at four times ED95 doses in swine previously documented to be MH-susceptible. In none of the 16 animals was MH triggered after administration of these relaxants, whereas all animals developed fatal MH after administration of halothane or halothane plus succinylcholine. Muscle biopsy specimens taken before administration of the relaxant confirmed that all animals had increased sensitivity to halothane, caffeine, or both. Thus, we conclude that doxacurium and mivacurium are not triggering agents of malignant hyperthermia in MH-susceptible swine.