The authors have no proprietary or commercial interest in any of the materials discussed in this article.

This study assessed the relationship between hematocrit levels and severity of obstructive sleep apnea (OSA) and examined how this relationship was affected by the degree of hypoxia as well as by possible confounding factors. Two-hundred sixty three subjects (189 men and 74 women) underwent nocturnal polysomnography with oximetry and had measurements of hematocrit, hemoglobin, white blood cell count, body mass index (BMI), blood pressure (BP), and 24-h urine norepinephrine (NE). Patients with severe OSA [respiratory disturbance index (RDI) >30] had significantly higher hematocrit values than patients with mild to moderate OSA or nonapneic controls (p < 0.01). However, only one patient had a hematocrit in the range of clinical polycythemia. Hematocrit levels were significantly correlated with BMI, BP, urinary NE, RDI, percent of time spent at oxygen saturation <90%, and with mean oxygen saturation. Multiple linear regression analysis revealed that mean oxygen saturation, RDI, and percent of time spent at oxygen saturation <90% were significant predictors of hematocrit level, even after controlling for gender, ethnicity, 24-h urine NE, BMI, and BP (p < 0.05). The severity of OSA is significantly associated with increased hematocrit, even after controlling for possible confounding variables. However, nocturnal hypoxemia in OSA does not usually lead to clinical polycythemia.

The value of parameters in Hertel’s exophthalmometry was measured by using orbit computerized tomography (CT) in this study. We selected images that revealed the center of the lens, the largest eyeball contour and the optic canal on the axial view of orbit CT. Parameters of exophthalmometry on orbit CT were the distance between the lateral orbital rims of both eyes (A), the shortest distance from the corneal center to line A (B), the B/A ratio, the distance between the lateral orbital rim and the medial orbital rim (C), the length of the line passing through the lens center from the apex to line C (D) and the D/C ratio. To compare the center position of the eye, we measure the axial length (E) and the longest distance between the corneal apex and the posterior pole (F) which is parallel to line B. We also calculated B-F/2 and Hertel-F/2 in order to know if there is a difference between measurements of orbit CT and of Hertel’s exophthalmometer. Subjects were classified into group 1 (aged 8–13 years old) and group 2 (aged 20 years old more). Sixteen subjects were enrolled in group 1 (32 eyes). In group 2, 100 subjects were male (200 eyes) and 35 were female (70 eyes). In group 1, the mean value was 89.94 mm for A, 13.49 mm for B, 35.13 mm for C, 10.64 mm for D, 24.40 mm for E, 24.20 mm for F, 0.15 for the B/A ratio and 0.30 for the D/C ratio. In group 2, the mean value was 100.93 mm for A, 15.03 mm for B, 38.78 mm for C, 12.03 mm for D, 24.62 mm for E, 24.33 mm for F, 0.15 for the B/A ratio and 0.31 for the D/C ratio. There was a statistically significant difference between the two groups for parameters A, B, C and D (p = 0.001), but no significant difference for the B/A (p = 0.239) and D/C ratios (p = 0.803). In the males and females of group 2, there was a statistically significant difference for the B/A ratio (p = 0.028). We suggest that the value of the D/C ratio (0.30–0.31) could be used as the index of protrusion. The normal values of exophthalmometry parameters measured by orbit CT could also be helpful to evaluate the exact protrusion in orbital diseases.

The authors have tried to improve RT technique using gasless TAA and achieved acceptable surgical outcomes. The rapid evolution of surgical robot technology and our constant effort to advance RT technique using gasless TAA would make it possible to reduce the perioperative morbidity and gain the best possible operative and oncologic outcomes.