Outcome of Mears procedure for Sprengel��s deformity

Background:

Sprengel’s shoulder is characterized by scapular maldescent and malposition, causing restriction of shoulder and cervical spine movements. It is associated with a variety of other congenital anomalies. Various surgical procedures have been described to treat this anomaly with no consensus as to the surgical procedure of choice. We report the results of the Mears procedure in the treatment of Sprengel’s shoulder.

Materials and Methods:

Seven children between the age group of two and six years were treated for Sprengel’s deformity, with omovertebral bar, and other congenital anomalies. The Cavendish score and Rigault radiological score were used to assess the severity of the deformity, and the position of the scapula relative to the cervical spine, respectively. The Mears procedure involved scapular osteotomy, par tial scapular excision, and release of a long head of triceps. Clavicular osteotomy was done only in two cases to decrease the risk of traction injury to the brachial plexus. Postoperatively, the patients were immobilized in a shoulder sling and range of motion exercises were started as early as possible. The patients were followed regularly at six weeks, three months and regularly at six-months interval.

Results:

The mean improvement in flexion and abduction was 45 ° (40 – 70 °) and 50 ° (40 – 70 °), respectively, which was the combined glenohumeral and thoracoscapular movement. The cosmetic and functional improvement by this procedure was acceptable to the patients. Minor scar hypertrophy was seen in two cases.

Conclusion:

The Mears procedure gives excellent cosmetic and functional results. This procedure addresses the functional aspect of the deformity and is much more acceptable to the patient and parents.     

Increased GABAergic output in the ventromedial hypothalamus contributes to impaired hypoglycemic counterregulation in diabetic rats

OBJECTIVE

Impaired glucose counterregulation during hypoglycemia is well documented in patients with type 1 diabetes; however, the molecular mechanisms underlying this defect remain uncertain. We reported that the inhibitory neurotransmitter γ-aminobutyric acid (GABA), in a crucial glucose-sensing region within the brain, the ventromedial hypothalamus (VMH), plays an important role in modulating the magnitude of the glucagon and epinephrine responses to hypoglycemia and investigated whether VMH GABAergic tone is altered in diabetes and therefore might contribute to defective counterregulatory responses.

RESEARCH DESIGN AND METHODS

We used immunoblots to measure GAD₆₅ protein (a rate-limiting enzyme in GABA synthesis) and microdialysis to measure extracellular GABA levels in the VMH of two diabetic rat models, the diabetic BB rat and the streptozotocin (STZ)-induced diabetic rat, and compared them with nondiabetic controls.

RESULTS

Both diabetic rat models exhibited an ~50% increase in GAD₆₅ protein as well as a twofold increase in VMH GABA levels compared with controls under baseline conditions. Moreover, during hypoglycemia, VMH GABA levels did not change in the diabetic animals, whereas they significantly declined in nondiabetic animals. As expected, glucagon responses were absent and epinephrine responses were attenuated in diabetic rats compared with their nondiabetic control counterparts. The defective counterregulatory response in STZ-diabetic animals was restored to normal with either local blockade of GABA_A receptors or knockdown of GAD₆₅ in the VMH.

CONCLUSIONS

These data suggest that increased VMH GABAergic inhibition is an important contributor to the absent glucagon response to hypoglycemia and the development of counterregulatory failure in type 1 diabetes.Iatrogenic severe hypoglycemia is the most serious acute complication in insulin-treated diabetes, and it remains the limiting factor in maintaining proper glycemic control (1,2). The brain, and particularly the ventromedial hypothalamus (VMH), plays a crucial role in sensing hypoglycemia and initiating the physiological counterregulatory responses that rapidly correct it (3–6), namely the release of glucagon and epinpehrine (7). In longstanding type 1 diabetes, however, these mechanisms are either lost or become impaired, making these individuals more susceptible to the threat of hypoglycemia (8). Although the mechanism(s) underlying these defects have not been identified, it has been postulated that impaired glucose counterregulation in type 1 diabetes stems from a number of factors. The first of which is the simultaneous loss of endogenous insulin secretion and, in association, the capacity to release glucagon in response to hypoglycemia (9). The latter is thought to be the result of a number of intra- and extrapancreatic factors, including the loss of β-cells and thus the capacity to suppress the local release of insulin (10–12), zinc (13,14), and the neurotransmitter γ-aminobutyric acid (GABA) (15) during hypoglycemia. These factors together, when coupled with excessive administration of exogenous insulin, act to suppress glucagon release. Second, adaptations that occur within the central and peripheral nervous system have been implicated in the impaired glucagon as well as epinephrine responses as well, including alterations in brain glucose and monocarboxylic acid transport and metabolism, and changes in neural innervation of the islet (16–23). The precise mechanisms and the relative contributions of the many disturbances in peripheral and central signals to counterregulatory failure in type 1 diabetes still are unclear.Glucose and glucose deprivation have been shown to alter GABA levels within the brain (24–27), but the evidence for its role in regulating glucose counterregulation remains somewhat controversial. Our laboratory reported that GABA acts within the VMH to modulate the magnitude of both the glucagon and epinephrine responses to hypoglycemia in nondiabetic rats (28). Subsequently, we demonstrated that increased GABAergic tone in the VMH was an important contributor to counterregulatory failure in nondiabetic rats exposed to recurrent antecedent hypoglycemia (29). Studies in nondiabetic humans also have shown that activation of GABA_A receptors with systemic delivery of the benzodiazepine analog, alprazolam, reduces counterregulatory and neuroendocrine responses to hypoglycemia in primates and healthy human subjects (30–32). Conversely, administration of modafinil to healthy human subjects to lower brain GABA concentrations was reported to improve adrenergic sensitivity and some aspects of cognitive function during hypoglycemia but did not significantly affect counterregulatory hormone release (33).The current study was undertaken to investigate whether GABA inhibitory tone is increased in the VMH in two rodent models of type 1 diabetes and whether GABA contributes to defective counterregulation during hypoglycemia in diabetes. Our data suggest, for the first time, that increased hypothalamic GABAergic neurotransmission plays a significant role in the loss of the glucagon response as well as the impairment of epinephrine release seen in rats with type 1 diabetes during acute hypoglycemia and that these counterregulatory defects are reversed by specifically reducing excessive GABA tone in the VMH.     

Manifestation of Long QT syndrome with normal QTc interval under anesthesia: a case report

Patients with congenital Long QT are known to have normal QT interval in symptom-free period and in the early years of life. Precipitating factors like surgical stress, interactions with anesthetic agents prolonging QT interval, and electrolyte imbalances can manifest with life threatening arrhythmias in congenital or acquired Long QT syndrome. We report a case of concealed LQTS manifesting under anesthesia and its subsequent perioperative course.