1. A method for implanting a rod implant along a spine of a patient back, the method comprising: a) minimally invasively passing the rod implant distally through a first minimally invasive incision in the patient back by causing a first end of the rod implant to distally displace along a first central longitudinal channel of a first elongated guide tool minimally invasively extending through the first minimally invasive incision from a first connection of a distal region of the first elongated guide tool to a head of a first bone anchor at a proximal region of the first bone anchor, the first bone anchor implanted in a first vertebra of the spine, and the head comprising a first rod-receiving channel; b) after the first end has minimally invasively passed through the first minimally invasive incision as recited in step a), exiting the first end from the first central longitudinal channel via a first longitudinally extending side slot of the first elongated guide tool and displacing the first end towards a second elongated guide tool along a trajectory diagonal to a longitudinal axis of the first elongated guide tool, the second elongated guide tool minimally invasively extending through a second minimally invasive incision from a second connection of a distal region of the second elongated guide tool to a head of a second bone anchor at a proximal region of the second bone anchor, the second bone anchor implanted in a second vertebra of the spine, and the head of the second bone anchor comprising a second rod-receiving channel; c) entering the first end into a second central longitudinal channel of the second elongated guide tool via a second longitudinally extending side slot of the second elongated guide tool; and d) causing the rod implant near the first end to enter the second rod-receiving channel and the implant rod near a second end of the rod implant opposite the first end to enter the first rod-receiving channel.
1. A method for implanting a rod implant along a spine of a patient back, the method comprising: a) minimally invasively passing the rod implant distally through a first minimally invasive incision in the patient back by causing a first end of the rod implant to distally displace along a first central longitudinal channel of a first elongated guide tool minimally invasively extending through the first minimally invasive incision from a first connection of a distal region of the first elongated guide tool to a head of a first bone anchor at a proximal region of the first bone anchor, the first bone anchor implanted in a first vertebra of the spine, and the head comprising a first rod-receiving channel; b) after the first end has minimally invasively passed through the first minimally invasive incision as recited in step a), exiting the first end from the first central longitudinal channel via a first longitudinally extending side slot of the first elongated guide tool and displacing the first end towards a second elongated guide tool along a trajectory diagonal to a longitudinal axis of the first elongated guide tool, the second elongated guide tool minimally invasively extending through a second minimally invasive incision from a second connection of a distal region of the second elongated guide tool to a head of a second bone anchor at a proximal region of the second bone anchor, the second bone anchor implanted in a second vertebra of the spine, and the head of the second bone anchor comprising a second rod-receiving channel; c) entering the first end into a second central longitudinal channel of the second elongated guide tool via a second longitudinally extending side slot of the second elongated guide tool; and d) causing the rod implant near the first end to enter the second rod-receiving channel and the implant rod near a second end of the rod implant opposite the first end to enter the first rod-receiving channel. 15. The method of claim 1 , wherein the first and fourth side slots are aligned with the first rod-receiving channel when the rod implant enters the first rod-receiving channel.