The Bundesliga leaders face an uphill battle to reach the quarter-finals after second-half goals from Son Heung-min, Jan Vertonghen and Fernando Llorente in the last-16 first-leg clash at Wembley.
Several players are said to have had haircuts in the team hotel after the final training session and team meeting, resulting in questions being raised about the focus of the squad.
Dortmund CEO Hans-Joachim Watzke assured that the hairdresser’s visit was an unrelated matter, but revealed that pre-match activities will be reviewed.
"It certainly has no influence on a team's performance,” Watzke told Bild.
“There are sporting reasons for our defeat, and we need to analyse them.
"It's clear the defeat also leads to a critical media view of the hairdresser's visit.
“And that's why [sporting director] Michael Zorc and [squad manager] Sebastian Kehl will review this with the players."
Dortmund welcome Spurs to the Westfalenstadion for the second leg on March 5.
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