Classification of Arachnoiditis

       Terminology                              Description                                   
       Arachnoiditis This term refers only to the presence of  inflammation involving the arachnoid
membrane.  Every person in the population
has probably experienced some degree of this during their lifetime.           
Arachnoid Adhesions This term indicates that some strands of
collagen scar are present.  A very common
entity which is rarely of clinical significance.
Adhesive Arachnoiditis
         (Focal)
Focal adhesive arachnoiditis is commonly
seen following trauma, local surgery, and
focal degenerative spinal problems.  Also fairly common and typically without associated clinical symptoms.
Adhesive Arachnoiditis
         (Diffuse)
Diffuse inflammation of the arachnoid with
varying degrees of scarring.  Usually due to
a toxic chemical agent being introduced into the subarachnoid space for diagnostic or treatment purposes. Even when the process
is extensive and advanced it is usually
without associated clinical symptoms if the individual's nervous system is given a chance to adjust to the progressive insult.  If acclimization does not occur or is de-stabilized the clinical symptoms of constant, intractable pain can be devastating to the individual.
Adhesive Arachnoiditis
         (Class I)
First phase of the diffuse inflammatory
process
.  A disease entity.
Adhesive Arachnoiditis
         (Class II)
Second phase of the diffuse inflammatory
process
. A disease entity.
Adhesive Arachnoiditis
         (Class III)
Most advanced phase of the scarring process (non-calcified).  A disease entity.
Arachnoiditis Ossificans
       
The most advanced phase of the process where the scar tissue begins to calcify.  Progressive nerve root compression is
common.  A disease entity.