“I didn’t know that back pain could be unilateral. it’s not from the left (healthy) side. it’s central and right accompanied by inflammation (burning sensation) exactly where the discectomy and laminectomy were done”. Nerve pain can mimic unilateral lower back pain. Sometimes it is difficult to differentiate.
“Isn’t nerve decompression comes “built-in” with fusion? when you restore proper disc height the foramen should be wide open and the is no herniated disc to pinch the nerve”. Not always. If there is a collapse of the disc allowing the nerve to be compressed, then the restoration of disc height through a fusion will decompress the root. If however, there is a mass in the spinal canal (herniation), the realignment by fusion will not decompress the root. You would need a direct decompression of that nerve root (microdiscectomy).
“Are different fusion techniques suitable for different pathologies? e.g (from what I saw and understood) ALIF could be a better option for single level fusion with no spine instability or deformities it’s less destructive and could be done without the support rods connected to spine by pedicle screws”. The answer is unsupported anterior fusions (ALIF/OLIF) without the posterior instrumentation (pedicle screws) has a much higher failure rate due to the lack of ability of anterior instrumentation to “grab hold” or “bite” into strong vertebral structures. This “lack of hold” allows motion which can lead to nonunion or “no fusion”.