In recent years, newer techniques have enabled increasingly smaller "donor" portions to be transplanted, leading to more cosmetically acceptable results and an increasing number of candidates selecting this solution for hair loss.
History

The use of both scalp flaps, in which a band of tissue with its original blood supply is shifted to the bald area, and free grafts dates back to the 19th century. Modern transplant techniques began in Japan in the 1930s, where surgeons used small grafts, and even "follicular unit grafts" to replace damaged areas of eyebrows or lashes. They did not attempt to treat baldness per se. Their efforts did not receive worldwide attention at the time, and the traumas of World War II kept their advances isolated for another two decades.

The modern era of hair transplantation in the western world was ushered in in the late 1950s, when New York dermatologist Orentreich began to experiment with free donor grafts to balding areas in patients with male pattern baldness. Previously it had been thought that transplanted hair would thrive no more than the original hair at the "recipient" site. Orentreich demonstrated that such grafts were "donor dominant", as the new hairs grew and lasted just as they would have at their original home.

For the next twenty years, surgeons worked on transplanting smaller grafts, but results were only minimally successful, with 2-4 mm "plugs" leading to a doll's head like appearance. Brazilian surgeons led the advances toward "micrografting", "minigrafting" and what is now called "follicular unit transplantation." With microscopic dissection of donor pieces from a resected portion of scalp, individual follicular units containing but 1-3 hairs could be prepared, and individually relocated into needle punctures in the recipient areas. With current techniques, upwards of 50 grafts per square inch are standard.

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