Compatible Anesthetic Protocol for TcMEPs

Induction:

• I.V. Anesthetics
• Narcotics
• Short-duration non-depolarizing muscle relaxant

Maintenance:

• N2O - 50 to 60%
• No volatile gases used
• Infusion of I.V. Anesthetics
• Infusion of Narcotics
• Muscle Relaxant: Preferably None, or Maintain NMJ block at 2 out of 4 twitches

Appropriate Spinal Cord Monitoring during Aortic Repair

In contrast to both SSEPs and Descending Neurogenic Spinal Cord EPs, muscle responses to stimulation of the motor cortex (known as Transcranial Motor Evoked Potentials or TcMEPs) are mediated solely by the corticospinal tract and offer a rapid detection of spinal cord ischemia attributed to loss of perfusion to the anterior spinal artery. TcMEPs are the safe, effective and preferred method of monitoring spinal cord motor function during the open surgical repair of thoracoabdominal aortic aneurysms. This technique is useful for localization of the critical segmental arteries and for detection of ischemia throughout the procedure.

Inappropriate Spinal Cord Monitoring during Aortic Repair

During repair of a Type I or II Thoracoabdominal Aortic Aneurysm, it is inappropriate to monitor spinal cord motor function by recording neurogenic responses to stimulation of the cervical or high-thoracic spinal cord.

As early as 1988, it was documented in the animal data that responses to cervical cord stimulation were not mediated by the corticospinal tract (Zapulla, et al). In 1990, Machida et al showed that sensory pathway responses remained intact and motor responses were immediately abolished in the lower extremities after ligation of the arteria radicularis magna - the primary feeder from the aorta to the anterior spinal artery (J Spinal Disorders. 1990 Dec;3[4]:345-52). In 1992, Su et al asserted that neurogenic responses in the legs to cervical cord stimulation were mediated by antidromic "back-firing" of the dorsal columns. This would be analogous to a backwards SSEP.

In the human data, both Toleikis (2000) and Deletis (2001) independently showed that such responses in the legs could be cancelled by performing sensory collision studies. In 2001, Minahan et al reported a few cases in which patients had emerged from spinal cord surgery with paraplegia even after they had "normal" responses to cord stimulation (click on the title of this post). These findings suggest that stimulation of the cord results in responses mediated by antidromic sensory activation and do not represent orthodromic motor activity.

General Billing Requirements for Interpreting Physicians

As licensed medical doctors, Interpreting Physicians are legally accountable for all bills submitted with their names, signatures, provider numbers, and tax ID numbers. Thus, all claims that are submitted containing an Interpreting Physician’s name and associated numbers should ONLY be submitted by his or her own office or preferred billing agent. According to our attorneys, when the Interpreting Physician is the primary biller, collections from such billing should always be received at the Interpreting Physician's location. Then, in accordance with federal guidelines, the Interpreting Physician may purchase a technical service provider's diagnostic test results (See "Purchasing Diagnostic Test Results").

Reimbursement of CPT 95920 is linked to remote physician supervision

Section 410.32(b) of the Code of Federal Regulations (42 CFR) legally defines physician supervision levels. There are basically two different types of physician supervision:

1. The Defined Levels are: 1, 2, 3, 4, 5, and 6
2. The CPT Specific Levels are: 6a, 66, 77a, 77, 21, and 22

The revised Medicare level for physician supervision of IOM is CPT-specific level #22. This specifies that reimbursement of CPT code 95920 is allowed when IOM is performed by a qualified technologist with on-line, real-time contact with a supervising physician. Many other insurance companies have adopted this Medicare guideline. Remote supervsion appears to be an ongoing, acceptable, and payable trend.

Purchasing Diagnostic Test Results

Section 30.2.9 of the CMS Medicare Claims Processing Manual states that an independent interpreting physician may receive payment for the technical component of a diagnostic test which is purchased from an eligible contracted independent entity (company or other physician).

Purchasing Physician Interpretations

Section 30.2.9.1 of the CMS Medicare Claims Processing Manual states that an independent entity that performs diagnostic tests may receive payment for the professional component of a test interpretation which is purchased from a contracted interpreting physician.

Reassignment of Benefits is NOT Required in Our Situation

According to the Code of Federal Regulations (42 CFR) and the Medicare Claims Processing Manual (Sections 30.2.9 and 30.2.9.1) there is no explicit requirement that a formal Reassignment of Benefits Statement be executed in the case of "Purchased Interpretations" or "Purchased Diagnostic Tests". Our service agreements do not involve reassignment at all, but are simply a means of purchasing interpretive services or test results.

HIPAA Compliance Agreements and "Covered Entities"

According to the Health Insurance Portability and Accountability Act (HIPAA) of 1996 (45 CFR) issued by the U.S. Department of Health and Human Services, health care providers are considered to be "covered entities" under federal law. According to our attorneys, this means that HIPAA compliance is implied and a written agreement between service providers is not required.