Background
Oblique and anterior lumbar interbody fusion have been widely performed in the lumbar spinal disease but we cannot get a direct decompression effect with these procedure. Objective: The purpose of this study is to report clinical and imaging outcomes of microscope assisted direct decompression combined with oblique lumbar interbody fusion (OLIF) or anterior lumbar interbody fusion (ALIF).
Methods
Twelve patients who received microscope assisted direct decompression during OLIF or ALIF for lumbar spinal stenosis were enrolled. The OLIF was performed for the lesion upper than the L4-5 or in the case of multisegmental disease. The ALIF was performed for the lesion at the L5-S1. After anterior-approaching surgery, percutaneous fixation of pedicle screw was performed and we did not perform an additional decompression posteriorly in all cases. For the clinical outcomes, we evaluated short form 36 (SF-36), Oswestry disability index (ODI) score and visual analog scale (VAS) pain score. For the imaging outcomes, we obtained postoperative lumbar magnetic resonance imaging (MRI).
Results
The OLIF was performed for 9 patients and the ALIF was performed for 3 patients. In the clinical outcomes, SF-36 was improved from 25.40 to 69.83 and ODI score was also improved from 69.83 to 16.50. VAS pain score of back was improved from 4.3 to 1.6 and VAS pain score of leg was improved from 7.5 to 2.2. In the imaging outcomes, all patients had severe stenosis before surgery. After surgery the severity of the stenosis was reduced to mild state in 9 cases and moderate state in 3 cases postoperatively.
Conclusions
We could obtain the good clinical outcomes and effective decompression through microscope assisted direct decompression during OLIF or ALIF.

Purpose
Anterior lumbar interbody fusion (ALIF) is widely accepted surgical technique in the treatment of lumbar degenerative disc disease, especially with foraminal stenosis. But many surgeons suspect the effectiveness of ALIF in one or multi-level lumbar degenerative disease. The aim of this study is to evaluate the effectiveness of the two-level ALIF in lumbar degenerative disease.
Materials and Methods
Included were the patients who had foraminal stenosis or spinal stenosis with segmental instability (e.g. spondylolisthesis). All patients were studied with plain radiographs and MRI before surgery and plain radiographs at 1 week, 6, 12 and 24 months after surgery. Radiographic measurements included disc height, global lumbar lordosis and existence of lateral fusion mass. To investigate the changes in lumbar global lordosis, the Cobb angle was evaluated on pre- and postoperative standing lateral radiographs from L1 superior endplate to S1 endplate. Union was defined as the presence of trabecular osseous continuity and/or less than 4° mobility between the segments on a flexion and extension radiograph. Details of blood loss, operative time, transfusions during hospitalization, hospital day, and perioperative complications were evaluated. Clinical outcomes were assessed using Visual Analogue Scale (VAS) scores for leg and back pain and Oswestry disability index (ODI) before surgery and at 6, 12 and 24 months after surgery. Paired t-test was used for statistical analysis.
Results
37 patients (10 men and 27 women; age 33-76 years, mean 61.1 years) who had undergone ALIF combined with PLF or percutaneous pedicle screw fixation (PPF) during January 2007 and January 2009 were studied retrospectively. The mean follow-up period was 34.2 months (48-25 months). The affected levels were L3-4-5 in 14 cases and L4-5-S1 in 23 cases. The average hospital days are 10.7 days, showing no difference between PLF and PPF surgery. The average operation time is 286 minutes. Blood loss was variable from 130 mL to 1200 mL (average 621.2 mL). But Blood loss during the ALIF operation was minimal. (220 mL ; range 120-540 mL). Global lumbar lordosis was improved from 29.2 to 37.8. Postoperatively all patients had relief of sciatic pain, and there were no techniqueassociated complications. Complications included sensory deficit (hypo/dysesthesia) in 4 patients, DVT in one patient, ileus in one patient and transient sympathetic symptom in 11 patients. Two patients had wound problem but were treated easily. The VAS score in leg pain was improved from 6.9 to 2.3 with statistical significance at 24 months after surgery. Also, ODI score was decreased from 30.8 to 9.2 significantly at 24 months after surgery. Radiologic evidence of solid fusion was observed in all patients on the basis of motion and screw loosening. The lateral bone mass was observed bilaterally in 26 of the 28 patients (92%). Radiologic ASD was found in 10/37(27%), but only one patient showed symptom and had minor surgery.
Conclusion
ALIF is an effective surgical strategy for the treatment of two-level lumbar degenerative disease and could be a useful alternative to posterior fusion surgery.