Neoplasia also includes direct seeding of the cerebrospinal fluid (CSF) from primary central nervous system (CNS) tumors such as glioblastoma multiforme, medulloblastoma, ependymoma, and choroid plexus carcinoma. Strictly speaking, the most common cause of arachnoiditis in failed back syndrome is not infectious or from cancer. It is due to non-specific scarring secondary to the surgery or the underlying pathology. Nerve injury
Laceration of a nerve root, or damage from cautery or traction can lead to chronic pain, however this can be difficult to determine. Chronic compression of the nerve root by a persistent agent such as disc, bone (osteophyte) or scarring can also permanently damage the nerve root. Epidural scarring caused by the initial pathology or occurring after the surgery can also contribute to nerve damage. In one study of failed back patients, the presence of pathology was noted to be at the same site as the level of  surgery performed in 57% of cases. The remaining cases developed pathology at a different level, or on the opposite side, but at the same level as the surgery was performed. In theory, all failed back patients have some sort of nerve injury or damage which leads to a persistence of symptoms after a reasonable healing time. Diagnosis
Avoiding post-laminectomy/laminotomy syndrome
Smaller procedures that do not remove bone (such as Endoscopic Transforaminal Lumbar Discectomy and Reconfiguration) do not cause post laminectomy/laminotomy syndrome. Management
Failed back syndrome (FBS) is a well-recognized complication of surgery of the lumbar spine.
Cervical dystonia (spasmodic torticollis): A type of dystonia that affects the head, neck and spine. It can create problems by the characteristic turning of the head and neck from side to side. Blepharospasm:  This type of dystonia causes involuntary contraction of the eyelids. The main concern for this dystonia is that it can cause the eyelids to close involuntarily and for indefinite periods of time. Oromandibular dystonia: A dystonia of the jaw, lips, and/or the tongue. It can make eating and swallowing very complicated due to the jaw being held open or shut for periods of time. Spasmodic dysphonia: A dystonia of the vocal cords. The complications surrounding this form of dystonia are speech related and can cause symptoms such as speech that wavers, speech that sounds like a whisper, or speech that is hesitant. Writers cramp (occupational dystonia): A dystonia that affects the muscles of the hand and  forearm. It is triggered by attempting to write or execute other fine-motor hand functions. Orofacial-Buccal dystonia (Meiges or Brueghals Syndrome): A combination of blepharospasm and oromandibular dystonia. Early-onset torsion dystonia: The most severe type of  dystonia, it begins in an arm or leg and progresses to the rest of the body until the person — in most cases, a child — is reliant on a wheelchair. Treatment
There is no cure for torsion dystonia. However, there are several medical approaches that can be taken in order to lessen the symptoms of the disease.