Mini-transforaminal lumbar interbody fusion (Mini-TLIF) and other minimally invasive approaches introduced for the purpose of treating lumbar degenerative disc disease and instability are achieving high success and safety rates as the conventional approaches. Moreover, it has less soft tissue damage, minimal blood loss, and less hospital stay.

A prospective study was conducted from 2012 to 2014 on 28 patients who were subjected to Mini-open TLIF combined with transpedicular screw fixation for spondylolisthesis and degenerative disc disease. Two paramedian approaches were done, 4 cm for each, to insert the pedicular screws, along with inserting unilateral TLIF cage with autologous bone graft. Decompression was done either unilateral or bilateral according to the patient side of radiculopathy. Sixteen patients (57.2%) were diagnosed with degenerative spondylolisthesis, 7 patients (25%) were diagnosed with isthmic type spondylolisthesis, and 5 patients (17.8%) were diagnosed with degenerative disc disease, 2 of them(7.1%) had previous operations at the same level. Twenty patients (71.4%) were operated at the L4/5 level, and 8 patients (28.6%) at the L5/S1 level.

All patients were able to ambulate the next day of surgery. The mean estimated blood loss was 251.79mL. The average hospital stay was 4.14 days. The average follow-up was 9 months. The mean visual analog scale was 1.86 at discharge, 1.68 after 3 months, and 1.38 after 6 months. After 6 months of the operation, MacNab's criteria were good in 23 patients and excellent in 5 patients. We had one case with transient weakness, 2 cases of screw malposition without clinical manifestations, and one case of infection.

Mini-TLIF approach is an efficient and safe approach for treating instability and degenerative diseases of the lumbar spine. The clinical outcome is encouraging and it may be an operation of choice for lumbar spinal fusion in selected patients.