With very large herniations, the entire cauda equina can be compressed and functionally compromised. This causes saddle anesthesia and can cause urinary retention and incontinence. Any claim of absolute contraindication would invariably be challenged. Often, these patients are the most insistent and difficult to manage. Occasionally, these are patients whose back pain improved after discectomy for a large central disc herniation.
Disc herniations are so ubiquitous that it is easy to be cavalier in diagnosis.
Step back and ensure the completeness of the workup prior to proceeding with the operation. All surgeons can recall several cases in which a diabetic plexopathy or an epidural metastasis was missed. Often, MRI is performed prior to plain radiographs. MRI is very sensitive in delineating lumbar disc herniations. Far lateral discs are best evaluated with this test.