Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UMHS researchers find clues to growing new jawbones in cancer patients after radiation therapy

23.10.2003


Poor bone quality in rats suggests new therapies to improve human treatment



In limited attempts with individual patients, varying surgeons have found mixed success in a method of growing new human jawbones after radiation therapy to treat head and neck cancer. While some patients have seemed to respond well to the technique, called distraction osteogenesis, others have not.

Researchers at the University of Michigan Health System are looking at how and why distraction osteogenesis works by studying rats and have found clues to the uneven clinical results. They will present their findings Wednesday at the American College of Surgeons Clinical Congress in Chicago.


Distraction osteogenesis is a method of regrowing bone in which the fractured bone is pulled apart millimeters at a time. As the fracture begins to heal, surgeons tug the bone further apart, tricking the body into thinking it must still work to heal the fracture. The body then begins to grow new bone to fill in the gap.

In two studies, UMHS researchers looked at distraction osteogenesis for reconstruction of the jawbone after radiation therapy. In one, the rats were given a low dose radiation; in the second study, the rats got a high dose of radiation. In both studies, new bone was formed. But looking at the new bone under a microscope revealed that it was of poor quality. There were obvious holes within the tissue and the bone was thin and brittle, showing signs of osteopenia (a precursor to osteoporosis). The high-dose radiation resulted in even lower quality bone.

"Clinical researchers are significantly limited in their ability to analyze their success and failure at the level of the bone. It would be difficult and invasive to take specimens from an actual patient’s bone after reconstruction and study the quality and strength. With our rat model, we can cut out the new bone and examine it. We can show that although you can distract, there are some problems with the bone after radiation, and we can determine what those problems are," says lead researcher Steven Buchman, M.D., associate professor of Plastic Surgery at the University of Michigan Medical School.

In humans, researchers would have difficulty making a comprehensive determination of the quality of the bone and the conditions that might improve it. So while it may appear under X-ray or clinical exam to be of normal quality, the overwhelming likelihood is that it is not.

The new research results indicate that the therapy needs to be significantly improved. Buchman says the poor bone quality could account for the uneven results in previous anecdotal clinical cases using distraction osteogenesis in irradiated cancer patients.

"The real significance is we’ve shown the new bone is far from perfect, and now we can look at therapeutic interventions to improve the process of creating new bone after radiation therapy. We have a very reasonable way to study it and determine if we can improve outcomes," Buchman says.

Distraction osteogenesis has been used since the early 1900s to grow and heal larger bones in the lower body. In 1995, surgeons began to use it for facial reconstruction, looking at growing new jaws for children born with small jaws or without jaws. Buchman, director of UMHS’s Craniofacial Anomalies Program, has had success using distraction osteogenesis on children and adults with jaw deformities.

Surgeons next began to wonder about its applications after cancer. Radiation often destroys or compromises the soft tissue in the head and neck. That makes bone grafts difficult after radiation therapy because the bone graft needs a new blood supply, which the irradiated tissue can’t supply. Free tissue transfers, in which tissue is taken from the leg or arm and reattached to the affected area, have been effective. But it’s a lengthy operation that leaves a scar in the leg or arm as well. Distraction osteogenesis has the potential to be an optimal solution.

"Now, knowing that distraction osteogenesis can produce new bone after radiation, we can test techniques and therapeutic interventions to help improve the bone quality. By studying this in the rat model, we can make sure the quality is there before transferring the technique to humans," Buchman says.


Funding for the research came from the National Institutes of Health, the Carls Foundation and the Plastic Surgery Education Foundation.

Nicole Fawcett | UMHS
Further information:
http://www.med.umich.edu/opm/newspage/reporter.htm
http://www.med.umich.edu/opm/newspage/2003/jawbone.htm

More articles from Health and Medicine:

nachricht Nitric oxide-scavenging hydrogel developed for rheumatoid arthritis treatment
06.06.2019 | Pohang University of Science & Technology (POSTECH)

nachricht Infants later diagnosed with autism follow adults’ gaze, but seldom initiate joint attention
24.05.2019 | Schwedischer Forschungsrat - The Swedish Research Council

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Novel communications architecture for future ultra-high speed wireless networks

17.06.2019 | Information Technology

Climate Change in West Africa

17.06.2019 | Earth Sciences

Robotic fish to replace animal testing

17.06.2019 | Ecology, The Environment and Conservation

VideoLinks
Science & Research
Overview of more VideoLinks >>>