Photo/IllutrationOkayama University Hospital’s Hisakazu Nishimori, second from left, and Uchiyama Manufacturing Corp.’s Akiko Kawaguchi, second from right, in Okayama’s Kita Ward on April 1 (Michiko Nakamura)

  • Photo/Illustraion

OKAYAMA--Plunging a syringe into human tissue right down to the bone is not for the squeamish nor recommended without practice, but it is the only way to extract bone marrow.

Volunteers are hardly lining up to be used as pin cushions, so medical students have few opportunities to practice skills that are deemed difficult to acquire in cases involving leukemia and other serious blood diseases.

Only medical interns are allowed to insert a syringe into a patient under the supervision of senior doctors.

But now help is at hand.

Okayama University Hospital here worked with a long-established local manufacturer of cork bottle caps to jointly develop a simple and reasonably priced tool that realistically replicates the process to extract bone marrow. It went on sale in early April.

Bone marrow extraction is an essential process for diagnosing leukemia, and hypoplastic anemia, an intractable illness. The diseases can only be identified by extracting a patient’s bone marrow, where blood is made.

During bone marrow testing, the examiner uses a syringe with a needle measuring 3 millimeters across to penetrate the subject’s hipbone to extract liquid or tissue of the bone marrow inside.

The examination requires fairly difficult manual skills, so medical students are typically only given opportunities during “practical training” to attend and observe the process.

Even when the students are permitted to rehearse the procedure, the training materials used are quite different from the reality of performing it on a patient. For example, an apple and a "kamaboko" board, a wooden base for kamaboko fish meat paste, are used to simulate human bone and its marrow.

Hisakazu Nishimori, an assistant professor at Okayama University Hospital’s Department of Hematology and Oncology, was desperate to find a realistic way to fill the void between observing the procedure and rehearsing with an apple and the real thing.

Nishimori started searching for materials that resemble bone marrow in texture and feel. His quest took him to hardware stores, where he went around touching all kinds of materials, including wood.

He wanted to find something that felt grainy, porous and dense at the same time. Something clicked, when he touched cork.

Nishimori approached a department at Okayama University that handles academic-industry collaboration, which put him in touch with Uchiyama Manufacturing Corp. in the city’s Naka Ward.

UMC began manufacturing cork bottle caps during the Meiji Era (1868-1912). The company now focuses on manufacturing and developing automobile parts. It had just set up a department called “new business development office” with an eye toward diversification when Nishimori got in touch.

"His proposal was something we had never imagined," department head Akiko Kawaguchi recalled. "Every one of us was surprised to learn that cork resembles bone marrow.”

In the event, UMC decided to take up the challenge.

Nishimori was given a number of cork samples with different densities by UMC to choose from for material to make prototypes based on combinations of hardness and thickness of the imitation bone part on the surface.

The product that won the day comprises an adapter base housing a cartridge made of cork. The cartridge, measuring 10 centimeters across and 8 cm deep, is covered by a layer of resin to imitate bone.

It allows the user to realistically sense, among other things, the distinctive feel of bone being penetrated and the motion of the hand grappling to extract tissue.

The product is marketed as “Kotsuzui Senshi Seikenjaa,” a name that Nishimori came up with.

“Kotsuzui” is Japanese for bone marrow. The other words are a pun designed to give a sense of intimacy.

“Senshi” is a Japanese homophone for “aspiration,” a medical term meaning puncture and “warrior.” “Seikenjaa” is Okayama dialect for “It’s biopsy!” Ending with “jaa,” it also sounds like a typical name for a warrior in children’s hero stories.

The product was unveiled at a meeting of the Japanese Society of Hematology in Osaka last October. When medical practitioners at the venue were invited to try it out, 90 percent of them said that it replicated texture of the real thing, officials said.

At least one university hospital has already begun using the product in a practical training class for students.

A “first-time set,” comprising an adapter base and a cartridge, costs 50,000 yen ($450). A replacement cartridge is available for 15,000 yen. Each cartridge can be penetrated about 50 times, officials said.