Analysis of the changes in scalp hair angles: In vivo and in vitro comparison before and after tumescence.

OBJECTIVES

To estimate the hair shaft exit angles and also to check the effect of tumescence on the hair angles.

MATERIALS AND

METHODS

Ten patients undergoing first session of strip hair restoration were included. The strip was marked at the level of external occipital protuberance and superior nuchal line. Three hairs were marked, one near upper end, one near lower end, and one in the middle. About 10 mL of 0.5% xylocaine with adrenaline was used with the needle in the subdermal level. The hair angles were measured. After the strip harvest, small slivers were prepared and photographed. The hair shaft exit angles of the three hairs were calculated using the computer software. The Kruskal-Wallis test and multiple comparisons (Bonferroni's correction) were used to analyze the data statistically.

RESULTS

The mean age of the patients was 23.4 years. The average preinjection (in vivo) hair angle was 52.82° with 52.96° in upper hairs (43.2° -61.2° ), 51.77° in middle hairs (43.4° -61.3° ), and 53.72° in lower hairs (38.4° -61.3° ). The average postinjection (in vivo) hair angle was 65.34° with 65.05° in upper hairs (55.1° -86.4° ), 65.63° in the middle hairs (56.4° -71.2° ), and 65.35° in the lower hairs (51.3° -75.2° ). Similarly, the postexcision (in vitro) hair angles was 71.91° with 70.83° in upper hairs (range, 56.8° -95.7° ), 72.19o in middle hairs (64.3° -78.5° ), and 72.71° in the lower hairs (63.9° -81.4° ).

CONCLUSION

The proper assessment of hair angles is very important and can be altered by the injection technique.