Medical Specialist!! (医療忍者!!, Supesharisuto!!) is chapter 164 of the Naruto manga.
Because Orochimaru is unable to fight in his current state, Kabuto battles Tsunade in his place. He informs Orochimaru that Jiraiya is nearby and likely en route, so they relocate. Jiraiya, Shizune, and Naruto just miss them, but pick up the trail. Unskilled with taijutsu and otherwise outmatched, Kabuto tries to end the battle quickly. He damages Tsunade's throat to disable her while keeping her alive, but she shirks it off and attacks him. He recovers and attempts to take advantage of her fear of blood, but Jiraiya and the others appear between them.