Thank you for your question.
From what you have described seems like you had L5-S1 laminectomy
appearing after surgery may be related to prolonged retraction or excessive traction on the nerve
though it can not always be explained. Traction has been recommended for less than 48 hours as its effect is only due to bed rest
. Traction by itself is very unlikely to have caused the numbness. The numbness may take long time to resolve upto 6 months and may not always resolve completely. If your pain is getting worse it is worth obtaining the MRI of lumbar spine
with and without contrast as it has already been 3 months, to find or rule out scar tissue or stenosis at the adjacent level.
Please let me know if I can be of further assistance.