Objective
To evaluate the efficacy and safety of anorganic bone matrix (ABM)/P-15 compared with local autograft bone in posterior lumbar interbody fusion (PLIF) with pedicle screws for degenerative lumbar diseases.
Methods
This is a retrospective analysis of consecutive series of 138 patients undergoing 1 or 2 levels PLIF from 2015 to 2020 in our single institute. Local autograft bone or ABM/P-15 (i-factor, Cerapedics Inc., Westminster, Colorado USA) were used for interbody fusion. The successful fusion was defined as the segmental cobb angle of less than 5 degrees of in flexion/extension X-rays and continuity of the trabecular bony bridging in computed tomography (CT) images.
Results
Among a total of 138 patients, total levels of fusion were 202, of which 74 were in 1 level fusion and 128 were in 2 level fusion. And 93 used ABM/P-15 and 109 used local autograft bone. The evaluation time of fusion status was 1 year after surgery. Successful fusion based on X-ray images was achieved 84.1% (90/107) for local autograft bone and 91.3% (84/92) for ABM/P-15 (p=0.127). Based on CT images, 86.9% (93/107) of autograft group and 95.6%(87/91) of AMP/P-15 group showed successful fusion respectively (p=0.034). Occurrence rate of autolysis was 14% (15/107) for local autograft bone and 17.6% (16/91) for ABM/P-15. Subsidence rates were 11.2% (12/107) for local autograft bone and 9.99% (9/91) for ABM/P-15. Hollow formation around pedicle screw was noted in 9.3% (10/107) for local autograft bone and 2.2% (2/91) for ABM/P-15.
Conclusions
The use of AMP/P-15 for lumbar interbody fusion surgery can be a good substitute for local autograft bone in terms of better fusion rate and similar complication rate on radiologically.

Extreme lateral interbody fusion (XLIF) and direct lateral interbody fusion (DLIF) are novel minimally invasive transpsoas approaches to the lumbar spine for performing fusions. Advantages of DLIF include easier technique, faster recovery, minimal complication, high fusion rate, and possibility of achieving better alignment. Many previous reports have evaluated outcomes of DLIF. The authors described surgical procedure of DLIF and reviewed clinical outcomes, radiological outcomes, and complications from various literatures. In conclusion, the DLIF seems to be a valuable minimally invasive surgical tool for the fusion in patients with various diseases, including degenerative disc disease, instability, stenosis, scoliosis, tumor, infection, and adjacent segment degeneration.

Protecting cranially located facet joints during pedicle screw placement is one of the modifiable factors that could prevent possible adjacent level problems related with spinal fusion procedure. Placing pedicle screws percutaneously appears to be more challenging in the technical aspect than performing with traditional open technique because of its limited selecting entry point for screw placement. The authors have reported surprisingly higher incidence and risk factors of cranial facet joint violations by percutaneously placed pedicle screws. The purpose of this literature was to illustrate the surgical technique focusing on the tips to avoid cranial facet joint violation during percutaneous placement of pedicle screws.