General Discussion

One of the contributors to foraminal stenosis is the osteophyte that arises from the inferior endplate of the cranial vertebrae, extending into the foramen.

Anecdotally, these seem to be present most often at L5/S1. I'm interested in hearing whether others here have had success addressing these L5/S1 osteophytes endoscopically. I feel like it should be something that can be accessed, but in practice I've had difficulty doing so successfully.

I find that in patients with even a moderately high crest, it is very difficult to reach the medial osteophyte via transforaminal approach due to the caudally-angled trajectory that's required. The more medial you go, the more inferiorly you travel within the foramen. You're also simultaneously trying to protect the exiting L5 root while crossing it dorsally, and I think the risk of DRG irritation is high.

More recently, I've tried taking a contralateral sublaminar approach. I've been doing these biportal, with the thought that I could use an osteotome to cut the osteophyte off flush with the vertebral body. While I've been able to resect the more medial aspect of the osteophyte successfully, I've found it difficult to follow the osteophyte laterally, particularly as the vertebral body and osteophyte begin to curve ventrally. Once I advance about the mid-pedicle line, I lose good visualization of the osteophyte and nerve root, which makes me hesitant to continue any sort of aggressive resection.

A couple thoughts I've had.

1) Start with a more lateral entry point. Currently I've been making my starting incisions at the ipsilateral medial pedicle line, but since I'm not trying to do any ipsilateral decompression, starting more laterally should provide me better access to the contralateral foramen. My thought would be on an axial slice, to connect the contralateral osteophyte to the ipsilateral spinolaminar junction, then extend that line to the skin to find the starting distance off midline.

2) Be more aggressive with resecting the contralateral ventral SAP. This "raises the roof" of the foramen and should give me better visualization of/access to the lateral foramen, allowing me to safely follow the osteophyte and nerve root out more laterally.

3) A combined approach - address the medial osteophyte using a sublaminar contralateral approach, and the lateral osteophyte via transforaminal approach.

For those who do both, I'm also interested in people's thoughts on doing this uniportal vs biportal. In a tight space, having the camera and instruments in-line might be easier than simultaneously trying to visualize the foramen while also fitting an off-axis instrument into that space. The uniportal drill is more controlled for drilling the osteophyte right up against the nerve. Also, having the beveled retractor would theoretically allow me to retract/protect the exiting nerve and be more aggressive with the osteophyte resection.

Would love to hear others' thoughts. Thanks in advance!