Larsen Syndrome and Associated Spinal Deformities.

Larsen syndrome is a rare genetic disorder that affects the connective tissue within the body. The present narrative review aims to examine the genetic basis of Larsen syndrome, clarify its symptoms, and define all the existing therapeutic approaches. A comprehensive search was performed in the PubMed database. Inclusion criteria considered molecular and clinical studies, management and surgical treatment of related deformities, case reports of patients with the syndrome, reviews of the associated anomalies, articles whose full text is available in PubMed, and articles published in the English language. Larsen syndrome is caused by mutations in the FLNB gene, which encodes the cytoskeletal protein filamin B, crucial in the development of the skeleton. Symptoms include joint dislocations, characteristic facial features and anomalies of the spine. Larsen syndrome may be conservatively treated initially, although surgical intervention is usually required. Various surgical techniques, including posterior spinal fusion, anterior decompression, circumferential arthrodesis, and single-stage 360° fixation, have been proposed along with growth-sparing procedures. Preoperative and postoperative care and education ensure optimal results. Further research is needed to identify novel therapeutic modalities for this condition.

Acute effects of smoking on skeletal muscle microcirculation monitored by near-infrared spectroscopy.

BACKGROUND: Cigarette smoking predisposes to vascular disease. Our study aimed to assess the acute effects of cigarette smoking on peripheral microcirculation using near-infrared spectroscopy (NIRS) and to compare microcirculatory function of smokers with that of nonsmokers. METHODS: We examined 65 healthy volunteers: 25 smokers (14 men and 11 women; age range, 20 to 27 years) and 40 nonsmokers (31 men and 9 women; age range, 19 to 38 years). Smokers had refrained from smoking for 2 h prior to the examination. Tissue O(2) saturation (Sto(2)), defined as the percentage of hemoglobin saturation in the microvasculature compartments, was measured with a probe placed on the thenar muscle. Sto(2) baseline values were recorded for 5 min. Subsequently, the brachial artery occlusion technique was applied to evaluate microcirculatory function before, during, and after smoking one cigarette. RESULTS: Sto(2) before smoking was 85 +/- 6% (mean +/- SD), not differing significantly between men and women (84.4 +/- 6.6% vs 85.6 +/- 5.8%, respectively; p = 0.721). Sto(2) did not change significantly during smoking. O(2) consumption rate was significantly greater in women (33.4 +/- 6.7 Sto(2) U/min vs 25.7 +/- 7.1 Sto(2) U/min, p = 0.032) at baseline and throughout the smoking session. O(2) consumption rate was reduced during smoking (p < 0.001) and at 5 min after the smoking session. Smoking had a significant effect on vascular reactivity (p = 0.015), with no significant differences between genders. Five minutes after smoking, vascular reactivity had returned to approximately normal levels. CONCLUSION: Smoking acutely affects microcirculatory function. NIRS is a noninvasive, operator-independent technique that can document these effects. It seems promising for the prospective evaluation of the effects of long-term exposure to cigarette smoke.