Minimally Invasive Midline Fusion - Unilateral Expandable Interbody Cage Placement
Dr Nitin Khanna, a leader in minimally invasive spine fusion, has presented his data at the Society for Minimally Invasive Spine Meeting 2020 on radiographic results with use of an expandable minimally invasive lumbar fusion device. The paper discusses the importance of minimally invasive cage position and presents a classification system to evaluate correct placement. His clinical results demonstrate 100% of cages placed in the A or B position.
A retrospective chart review was performed on 17 consecutive patients who underwent a midline lumbar fusion utilizing a single expandable interbody device.
Post-operative radiographs were examined to determine device position, relative to the vertebral bodies.
Device positioning was graded A, B, or C based on the presence of device midline in the medial, middle or lateral third of the superior vertebral body
9 devices were graded "A"; 8 devices were graded "B". None received a grade of "C"
Many surgeons have preferred to utilize a single cage for minimally invasive fusions. The use of a single cage presents a significant challenge as it is difficult to obtain a 30-45 degree angle in order to position the cage in the middle third of the vertebral body
The advantage of the expandable lordotic oblique cage for this procedure is the placement of the cage in the optimal radiographic position prior to expansion
Further research examining subsidence and fusion rates as well as segmental lordosis utilizing this modified midline fusion procedure requires exploration.
