Transection

Transection is the injury that turns a graft into a loss before it ever reaches the recipient area: the follicle cut, crushed or bent sharply enough during extraction or dissection that it cannot survive transplantation. The transection rate — damaged units as a share of attempts — is the core quality metric of a harvesting team, and one of the few numbers in this field that can be measured during the case rather than a year later.

In FUE, transection happens where the punch meets a follicle it cannot see. Follicles descend at an angle that differs from the visible shaft angle, splay below the surface, and curve — dramatically so in tightly curled hair. Punch diameter, sharpness, scoring depth and the alignment of the operator’s wrist decide whether the extracted cylinder contains an intact unit or a divided one. In strip surgery the risk moves to the bench, where dissection under magnification protects follicles only as well as the bench team is trained.

The countermeasures are unglamorous: proper tumescence to stabilise tissue, punch selection matched to the patient’s follicle geometry rather than to habit, controlled scoring depth, and — above all — inspection. Serious teams examine grafts under magnification as they are sorted, log partial and complete transections separately, and feed the number back to the operator during the session, so technique adjusts in minutes rather than after a poor result.

Rates worth trusting come with a counting method attached. Commonly cited targets sit in the low single digits for experienced hands, but the honest figure is whatever the bench actually logs — and it varies legitimately with hair curl, skin character and graft type, which is why tightly curled donor hair deserves specific experience rather than generic confidence. A quoted rate with no protocol behind it is an ornament.

Speed pressure is the silent driver: transection climbs when harvest pace is set by the schedule rather than by the tissue. That makes the metric a good probe of how a clinic really runs — and, in training settings, the single most useful number for tracking a new operator’s learning curve.