The patient was operated by me 23-August-2013 for spondylolisthesis L5-S1 and extruded disc L4-5. Transpedicular screw fixation L4,L5 and S1 was done with insertion of TLIF at L5-S1 level, using Alphatec Spine Isobar TTL module in system. The patient noticed escalation of right sciatica 12-September-2013. Check X-ray done 19-September-2013 showed slipping of the rods: the right slipped down 10 mm and the left up for the same distance, but it was not noticed by me at that time. Check for infection was negative. The patient was treated conservatively. The patient then came 24-November-2013 claiming that the LBP and right sciatica still the same last month and he is feeling click in the back. The right sciatica persist even when sleeping. Control X-ray done 23-November-2013 showing the same picture as before with more slippage of the rods. The transpedicular screws are in good position. SLRS was 80 degrees both sides with pain in the left. There is no sensory motor deficit.

MRI lumbar spine done 25-November-2013 ruled out escalation of other events.

The old incision refreshed and the nuts exposed. The left rod was shifted up and out of the lower nut. The same finding was seen in the right upper nut. The connector was in place with the left nut was loose. All the nuts in the left rod were loose, but in place. The connector, all nuts and both rods were removed. The transpedicular screws were in good condition. The old rods were 5 cm length. New rods 65 mm long with more bending than the previous ones were inserted and about 15 mm away from the upper and lower nuts were fixed tightly and new cross connector was applied. Vigorous physical strain was applied after that, to ensure that no loose elements are present. Routine closure of the wound. The stages of surgery were documented by the C-arm.

Smooth postoperative recovery.

It is the first time happening that both rods slipped out the nuts. It is recommended to change the rod construction to be beaded, to prevent escalation of such events, or at least to have rods with several lengths with widened spherical endings, to prevent outside slipping of the nuts.