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The Eyes Are the Window to the Brain: New Brain Surgery Procedure Finds Success Thanks to Medical Device Standards

Surgeons at Johns Hopkins have successfully used a new procedure for brain surgery that involves entry through an incision in the eyelid, rather than through the top of the skull. This method, which is considered to be less invasive and less damaging, is made possible with the help of medical device standards.

In the procedure, doctors make an incision in the natural crease of the eyelid to access the brain. A microscope- and computer-guided endoscope, fitted with a camera, is then used to thread other surgical instruments into the soft tissue to perform the operation.

The method is expected to be viable for several kinds of brain operations, including removing cancerous tumors, correcting broken skull bones caused by trauma, and correcting spinal fluid leaks that can result from previous, more invasive skull surgeries.

The new procedure is supported by standards for medical devices. One such standard assures the quality and durability of the tools used to make the eyelid incision. ASTM F1089-02, Standard Test Method for Corrosion of Surgical Instruments, was developed by ASTM International, a member and audited designator of the American National Standards Institute (ANSI).

The design of surgical equipment is also guided by ANSI/AAMI HE75:2009, Human factors engineering - Design of medical devices. This American National Standard helps to make medical devices easier to use and less prone to user error, which in turn can lead to more successful surgeries. This standard was developed by the Association for the Advancement of Medical Instrumentation (AAMI), an ANSI member and accredited standards developer.

High-tech maps created by advanced computed tomography (CT) and magnetic resonance imaging (MRI) scans of the brain are critical to the procedure, guiding the path of the surgical instruments that will be used in the operation. These scans are also covered by standards, such as IEC 62464-1 Ed. 1.0 b:2007, Magnetic resonance equipment for medical imaging - Part 1: Determination of essential image quality parameters. Developed by the International Electrotechnical Commission (IEC), this standard specifies measurement procedures for the determination of many essential medical MR equipment image quality parameters.

This standard was developed by the IEC Technical Committee (TC) 62B, Diagnostic Imaging Equipment. The United States National Committee (USNC)-approved Technical Advisory Group (TAG) Administrator for this TC is the Medical Imaging & Technology Alliance (MITA). MITA is a division of the National Electrical Manufacturers Association (NEMA), an ANSI member and accredited standards developer.

Endoscopes are another key element of the procedure. These tiny tools are inserted through the eyelid to allow the surgeon to examine the brain. Standards are in place to assure the performance of these tools, including ISO 8600-1:2005, Optics and photonics -- Medical endoscopes and endotherapy devices -- Part 1: General requirements. This standard provides terms and definitions essential to the development and use of endoscopes.

This document was developed by the International Organization for Standardization (ISO) Technical Committee (TC) 172, Optic and photonics, subcommittee (SC) 5, Microscopes and endoscopes. The ANSI-accredited U.S. TAG Administrator for this TC and SC is the Optics and Electro-Optics Standards Council, an ANSI member and accredited standards developer.

With the help of standards, this new medical advancement may make many brain surgeries less labor-intensive for doctors and easier to recover from for patients. To learn more, see this Science Daily article.


Jana Zabinski

Senior Director, Communications & Public Relations


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Beth Goodbaum

Journalist/Communications Specialist


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