Combined Transforaminal Lumbar Interbody Fusion and Smiley Face Rod Technique Using Dual-Headed Pedicle Screws for L4 Isthmic Spondylolisthesis and L5 Spondylolysis

Abstract

Spondylolysis with pseudarthrosis may be treated surgically by repairing the spondylolysis using the smiley face rod (SFR) technique. The SFR technique can avoid adjacent segmental disease caused by transforaminal lumbar interbody fusion (TLIF), which is one of the main surgical techniques to treat isthmic lumbar spondylolisthesis. A 59-year-old woman had been playing softball since she was 12 years old and was a member of a prefectural representative team. She sought treatment because of numbness in her left lower limb and difficulty playing softball. Despite conservative treatment for a year, her symptoms did not improve. Physical examination revealed decreased patellar tendon reflexes and numbness and pain from the front of the thigh to the lower leg without muscle weakness. Imaging showed L4 isthmic spondylolisthesis with Meyerding classification grade 2 anterior slip and L5 spondylolysis with pseudarthrosis. We diagnosed L4 radiculopathy caused by L4/5 foraminal stenosis and L4 isthmic spondylolisthesis with L5 spondylolysis. She underwent surgery combining the TLIF of L4/5 and the SFR technique of L5 using dual-headed pedicle screws that can fix two types of rods with L5 pedicle screws. Three months after surgery, fusion between L4/5 and fusion of the L5 pars cleft were confirmed. She resumed sports, and one year postoperatively, she was able to participate in softball games. Two years postoperatively, she could bat, run, and play defense without adjacent segmental disease. Two-segment TLIF increases adjacent segmental disease more than single-segment TLIF. Because the L5 spondylolysis had not slipped, we chose the SFR technique to preserve mobility at L5/S1. The dual-headed pedicle screw fastens two-type rods at the head of the pedicle screw, making it a suitable design for this procedure.