The key to getting maximum reimbursement for your IONM procedures 
is to keep yourself upto date with the payers clinical guidelines. Each individual carrier publishes the policies which outlines the rules and regulations regarding the use of a particular CPT, its limitations of coverage and/or medical necessity of that procedure.
It is amazing to see how one payer will pay for neurophysiological services for a spinal surgery due to disc degeneration while others may deny it stating not medically necessary. Not knowing the payer specific guidelines could mean a dip in your reimbursements. These guidelines issued by the payers not only defines the policies of IONM but they also outline the documentation requirements for such procedures necessary for reimbursements.
Not all policies are the same for all the carriers and not all the carriers have policies regarding every CPT code in the CPT manual. While most commercial carriers may have similar or identical policies but it should not be assumed that they are always the same. Even Medicare policies differ from state to state based on the CMS contractors. So it is always a good idea to check for LCD (Local Coverage Determination) defining the policies for IONM in your state. Here are some examples of how guidlelines differes from carriers to carriers and state to state –
Recently Highmark BlueShield of Pennsylvania issued their IONM policy effective January 1st 2012, which is significant to the point where they have stated that “Intraoperative neurophysiology monitoring should be reported under procedure code 95920, regardless of the specific monitoring performed (e.g., brainstem auditory evoked response, somatosensory evoked potentials, etc.). If any of the testing codes for neurophysiological monitoring which are addressed below in the “Description” area of this policy are reported in conjunction with 95920, the services should be combined and processed under 95920 (e.g., 95925 + 95920 = 95920).” This is a substantial change because this means that you can no longer bill SSEPS and MEPS on your claim and that means your receivables are going to get a hit.
On the other hand, payers like Aetna, Cigna, IBX etc. states that baseline study is separate and distinct from the intraoperative monitoring and each procedure can be reported separately.
In another example: CMS contractor Trailblazer (CO, NM, OK, TX) has different guidelines for billing IONM services. According to LCD 2924, this LCD imposes utilization guidelines limitations which is ” Bill only for physician time. Bill each minute of the physician’s timeonce. If multiple patients are monitored simultaneously, bill with CPT code 95999“.
Whereas CMS contractor like NAS (Noridian Administrative Services, LLC) for Arizona describes in their LCD “Intraoperative neurophysiological testing (CPT code 95920) is an add-on code to be filed in addition to the primary procedure(s), e.g., SEP (CPT codes 92585, 92586, 95925, 95926, 95927, 95928, 95929,95930). The primary procedure(s) covers the usual test time of 30-60 minutes. Providers may bill one unit for 95920 for each additional 60 minutes of monitoring beyond what is covered for the primary procedure“.
In another example: Blue Cross and Blue Shield of Alabama considers Intraoperative Neurophysiologic Monitoring which includes SSEPs, BAEPs, EMG of cranial nerves, EEG, motor evoked potentilas using Transcranial electrical stimulation and ECog to be medically necessary during fracture of spine, scoliosis, spial stenosis, spondylolisthesis or spondylosis, carotid endarterectomy etc. For the complete description of the conditions please refer to policy no. 306.
Whereas Novitas Solutions which serves as the Part B Medicare Administrative Contractor (MAC) for Jurisdiction 12 (J12), which includes Delaware, New Jersey, Pennsylvania, Maryland, the District of Columbia and the counties of Arlington and Fairfax in Virginia and the City of Alexandria in Virginia, in their LCD L27499 imposes ICD-9 limitations that support diagnosis to procedure code. For example spinal stenosis, disc degenerative diseases, spondylosis, Postlaminectomy Syndrome, Compression Fractures etc. are not considered medically necessary. For complete coverage of the policy please refer to LCD L27499.
As one can note from above examples that policies vary from carrier to carrier and to reduce denials one should stay abreast of such policy changes. It is very important to verify each payer’s policies and especially when there is a denial to see if the denial is valid. Monitor these policies frequently as payers update them on a regular basis. If a denial is not justified, support your appeal with the copy of the clinical guidelines. Be sure your practice is up to the speed with these revisions to ensure proper insurance reimbursements and reduced claims denials.