News in brief– Highlights from the latest news and research in medical devices

10.1586/17434440.5.2.109 © 2008 Future Drugs Ltd ISSN 1743-4440 109www.future-drugs.com

Deep brain stimulation boosts memory and invokes flashbacks

Researchers at Toronto Western Hospital performed deep brain stimulation on the hypothalamus of a morbidly obese man to try to reduce food cravings and induce weight loss but instead found that this evoked detailed

autobiographical memories and improved memory function.

The team, led by Clement Hamani,aimed to alter the 50-year-old man’sfeeding behavior and treat his obesity byelectrically stimulating the hypothala-mus, the area of the brain that helps toregulate certain metabolic processes.

The subject was awake but anesthe-tized during the procedure; DBS elec-trodes were implanted into both sidesof the hypothalamus and potential siteswere identified by asking the patient toscore between 1 and 10 how hungry hefelt when stimulated. The electrodeswere then secured in position and apulse generator was also implanted. In-depth neurological assessments weremade at the time of the surgery and, 3weeks later, ‘on–off ’ tests were also per-formed so the subject did not knowwhen the electrodes were switched on.They also performed radiological test-ing after 1 month of DBS to see whichareas of the brain were being activatedby the stimulation.

They unexpectedly found that whenstimulated to a certain threshold, at a cer-tain point on the hypothalamus, the sub-ject reported a feeling of déjà vu and feel-ing like he was 20 years old again, in apark with friends and his girlfriend fromwhen he was that age. As the voltage wasincreased, the details of the memoriesbecame clearer and more intense. Associa-tive memory tasks found that stimulationincreased recollection but not familiarity-based recognition. At 3 weeks after sur-gery there were significant improvementson two of the verbal and spatial learningtests, compared with the scores at thetime of surgery. The radiological testingshowed that hypothalamic stimulation in

this subject modulated activity in themesial temporal lobe and influencedmemory functions.

“The subject reported a feeling of déjà vu and feeling like he was

20 years old again.”

In the first 6 months of DBS at high fre-quency there was no change in the weightof the subject but when a lower frequencywas used, the patient lost 12 kg over 5months; he experienced reduced foodcravings and had a decreased tendency tobinge with stimulation. However, duringthe last 4 months of the study, the patient

purposely turned the stimulator off andhis night-time binging returned and heput back on all of his lost weight.

This study has accidentally foundsome very surprising and encouragingresults regarding memory recall andhas shown that it may be possible tomodulate memory function by apply-ing electrical stimulation to variousareas of the brain.

Sources: www.nhs.uk/News/Pages/NewsIndex.aspx

Hamani C, McAndrews MP, Cohn M et al.

Memory enhancement induced by

hypothalamic/fornix deep brain stimulation. Ann.

Neurol. 63, 119–123 (2008).

Doctors able to feel organs using a display screen

Erik Vidholm at the Center for ImageAnalysis at Uppsala University (Sweden)has been involved in developing a newtechnology that uses computerizedimage analysis to determine the size oforgans, or to construct 3D models oforgans when surgery or radiation isbeing planned. It is thought to be afuture possibility for a 3D mouse to beused so doctors can feel their images.

Modern imaging techniques areimproving all the time and the resultingimages can be very complex and diffi-cult to interpret. The Center for ImageAnalysis is just one institution that istrying to establish better methods forexploration and analysis of these imagesfor both diagnostic and treatmentplanning purposes.

“Modern imaging techniques are improving all the time and the resulting images can be very

complex and difficult to interpret.”

One of the interactive methods thatis being developed by the teaminvolves the mouse and keyboardbeing replaced by a pen-like 3Dmouse, which enables the user to feelthe virtual organs. Computer modelscan be adapted to the images of organsand can then be used to measure thevolume and shape of the organ, forexample.

Source: www.uu.se/news

110 Expert Rev. Med. Devices 5(2), (2008)

News in Brief

PET better at detecting treatment response

CT and MRI scans provide anatomicalimages of the area being scanned, whereasPET imaging shows the biologicalfunctioning of the region in real time.

The response of a solid tumor to treat-ment is currently evaluated usingResponse Evaluation Criteria in SolidTumors (RECIST); CT or MRI scansbefore and after treatment are comparedto find the change in tumor size. TheRECIST criteria grades the tumor aseither stable disease, progressive disease,complete response, or partial response.

If conventional imaging and evaluationfails to accurately show response to treat-ment, successful therapies may be discon-tinued. If a patient is not responding, using

PET scanning to evaluate response couldhelp prevent them from undergoing toxictherapies that are not working.

“We knew from our considerable expe-rience with neoadjuvant therapy (treat-ment before surgery) in sarcoma patients,that measuring tumor size correlatedpoorly with response,” said Dr Fritz Eil-ber, Assistant Professor of Surgery, Direc-tor of the Sarcoma Program at UCLA’sJonsson Cancer Center and senior authorof the study. “We have removed manytumors that have not changed in sizewith treatment or have even grown, butare completely dead on pathologic analy-sis. Just because the tumor doesn’t shrinkdoesn’t mean the treatment didn’t work.”

The aim of the study was to evaluatewhether PET with 18F-fluorodeoxyglu-cose (FDG-PET), which measures sugarmetabolism in cells, allows for a more accu-rate evaluation of histopathologic response.A total of 42 patients with biopsy-provenhigh-grade soft-tissue sarcoma had a FDG-PET/CT scan before and after neoadjuvanttreatment. Changes in tumor FDG uptakeand size from the baseline to the follow-up

scan were calculated. The scanner used inthis study combines two imaging modali-ties in one machine, allowing the research-ers to directly compare the scans for tumorsize (measured by CT) and metabolicactivity (PET).

“PET was much more sensitive in pick-ing up response than size-based RECIST,”Eilber said. “RECIST missed a large per-centage of patients that actually had aresponse. PET picked up all of theresponders.”

This study raises questions about the waytumors are monitored during and aftertreatment. Patients should not undergounnecessary treatment or be removed fromtherapies that are working. Eilber and col-leagues are working to confirm their resultsin a larger study and testing new metabolictracers to assess treatment response.

Sources: www.cancer.mednet.ucla.edu

Evilevitch V, Weber WA, Eilber FC et al. Reduction

of glucose metabolic activity is more accurate than

change in size at predicting histopathologic response

to neoadjuvant therapy in high-grade soft-tissue

sarcoma. Clin. Cancer Res. 14, 715–720 (2008).

A study by Jonsson Comprehensive Cancer Center at University of

California, Los Angeles is one of the first to directly compare PET to CT scanning and has shown that PET

imaging is significantly more sensitive and accurate when

measuring treatment response in sarcoma patients.

New adhesive modeled on a gecko’s footEngineers at the University of California,Berkeley (CA, USA), have developed anew adhesive inspired by the sticky feet ofgeckos, which have the ability to climbvertical walls and ceilings. Whereas stand-ard tape or glue sticks to a surface whenpressed onto it, this new adhesive sticks asit slides onto a surface and lifts off withminimal force and no residue.

The material is made from millions ofplastic fibers that establish grip; 42 mil-lion hard plastic microfibers weresqueezed onto each square centimeter.The microfibers are made of polypro-pylene, and are 20 µm long and 0.6 µmin diameter.

They found that on a smooth, clean,vertical surface, two square centimeters ofthe adhesive could hold 400 g. The struc-ture is similar to a microfiber array devel-oped by the same group in 2006. That

material relied upon friction to work butrequired the application of force to makeit stick. Changes made to the plastic back-ing enabled the directional adhesionreported in this new material to work ontruly vertical surfaces.

What sets this new gecko-inspiredadhesive apart from others created so far isthat it is directional, only ‘sticking’ whenit slides along a smooth surface, not whenit is pressed down.

“This difference is critical because ifyou’re climbing up vertical surfaces, youcan’t afford to use a lot of energy pressingdown into the surface to stick,” said coau-thor, Professor Ron Fearing. “Using forceto attach also requires force to detach. Agecko running uphill may be attachingand detaching its feet 20 times a second,so it’d get very tired if it had to work hardto pull its feet off at every step.”

Similar to gecko fiber arrays, the syn-thetic patch maintains contact andincreases shear force with sliding. Thehigh shear force observed (∼210 nN perfiber) suggests that fibers are in side con-tact, providing a larger true contact areathan would be obtained by tip contact.Shear force increased over the course ofrepeated tests, suggesting deformation offibers into more favorable conformations.

So far the new adhesive only works onsmooth clean surfaces so the next aim ofthe team is to develop the material so thatit can adhere to rough surfaces and that itis self-cleaning.

Sources: http://newscenter.berkeley.edu

Lee J, Majidi C, Schubert B, Fearing R. Sliding

induced adhesion of stiff polymer microfiber arrays:

1. Macroscale behaviour. J. Royal Soc. Interface

(10.1098/rsif.2007.1308)

News in Brief

www.future-drugs.com 111

Better medical device information needed to help patients and doctors

“These days, patients are asking theirdoctors for the newest technologiesfrom genetic tests to specific radiationtreatments, and many physicians don’tknow where to turn for the latest evi-dence-based information,” commentedMitchell D. Feldman, Professor of Med-icine at UCSF (CA, USA) and corre-sponding author of the study. “Some-times, the only information out there iswhat the manufacturer provides.”

The team suggests that after US FDAapproval has been obtained for a newmedical device, an ‘evidence based’ tech-nology assessment should be conductedby an independent organization toensure that the devices are in fact safeand beneficial, and to provide data thatcan increase awareness of “the potentialpromise and pitfalls of new technology”,the team writes.

“Patients are asking their doctors for the newest technologies...

and many physicians don’t know where to turn for the latest

evidence-based information.”

The analysis from the UCSF evalu-ated the federal review process, themethod by which devices come to mar-ket, how the scientific literature reportson clinical trials involving medicaldevices, and the effectiveness of inde-pendent review boards in improving atechnology’s medical benefit to patients.They found that out of the thousandsof medical technology applications

Researchers from the University of California, San Francisco, claim that

the approval process for new medical devices does not involve the same level of scrutiny as the

approval process for new drugs and this should be addressed to ensure the safety of any devices that are

approved for public use.

submitted annually to the FDA, lessthan 100 undergo the kind of scrutinythat is required for new drugs. It is alsoreported that the agency relies on man-ufacturers and clinical investigators toinitiate recalls and failure reports whena technology has been revealed to benot beneficial or is potentially harmfulto patients.

“FDA approval should be the start ofthe process toward clinical application,not the end,” Feldman said. “Physiciansand patients just aren’t aware of the lim-itations of the FDA process of initialassessment and oversight of new medi-cal technologies. Assessments by objec-tive entities are a necessary addition toFDA approval – so that deficiencies inclinical evidence, and patient safety

issues that may arise after approval, arerecognized before widespread adoptioninto clinical practice.”

One example of an independentreview organization that should beinvolved in the medical device reviewprocess is the California TechnologyAssessment Forum (CTAF; CA, USA),which was profiled in the report by theUCSF team. The CTAF is a commu-nity forum that is dedicated to objectiv-ity and transparency regarding medicaltechnologies; a community forum fordialog and decisions regarding thesafety and effectiveness of new andemerging technologies.

Sources: http://pub.ucsf.edu

www.ctaf.org

Robotic technique to improve hip surgery training

Professor Justin Cobb, Head of theBiosurgery and Surgical TechnologyGroup at Imperial College London(UK), has conducted a trial on 32undergraduate medical students to testwhether planning before an opera-tion, combined with the latest naviga-tion equipment, could increase thesuccess rates of students practicing hipresurfacing arthroplasty procedures, amethod to correct hip bone deform-ities by coating the femoral head witha chrome alloy cast.

Until now inexperienced surgeonshave only been able to learn and gainthe necessary experience to carry outhip resurfacing operations by repeatedly

performing the operations, risking theneed for painful and expensive correctiveoperations for patients.

The tested navigation tool was AcrobotNavigation, which is similar to a GPStracking system. It helps the surgeon tonavigate during surgery by plotting cor-rect surgical incisions and calculating thecorrect angles for inserting chrome alloyparts needed to repair hip bones.

The tried and tested device has twodigital arms protruding from a console.One arm senses the movement of surgi-cal tools, the other takes detailed imagesof the bones. Information is fed intosoftware, generating a virtual model ofa patient’s hip as it is being operated on,allowing the user to plot the progress ofan operation as it is being performed,which is a vital technique for ensuringthat it is being carried out correctly.

Source: www.imperial.ac.uk/news

Device: Acrobot® Navigation System

Subjects (n): 32

Indication: Surgical navigation

112 Expert Rev. Med. Devices 5(2), (2008)

News in Brief

Biodegradable film to reduce scarring after heart surgery

Researchers at the Society of Thoracic Surgeons annual meeting in Fort Lauderdale announced the safe and effective use of a new biodegradable film in the reduction of scarring in young children undergoing open heart surgery.

REPEL-CV® Adhesion Barrier is a bio-absorbable adhesion barrier film that isdesigned to be placed over the surfaceof the heart at the conclusion of a surgi-cal procedure. The presence of REPEL-CV on the surface of the heart isintended to block the transmission offibrin, a blood component and,thereby, prevent the formation offibrous bands of scar tissue, known asadhesions, between the surface of theheart and surrounding tissue surfaces.

Scarring can be a troublesome occur-rence when multiple surgeries arerequired to treat a patient. It is a normalpart of the healing process but makesfollow-up surgeries much more difficultand lengthy.

“With adhesions, we have to cutthrough tough, fibrous tissue in verydelicate areas – not just between theheart and the sternum, but also in otherareas between vessels and cardiac cham-bers… Often the scarring is severeenough that when we perform a secondsurgery, we find the heart is stuck to the

sternum… This increases the amount oftime a patient has to be under anesthe-sia and potentially could involve morebleeding and the need for transfusion orother blood products,” says Dr AndrewLodge, Pediatric Cardiothoracic Sur-geon at Duke University MedicalCenter (NC, USA) and study leader.“So we are very interested in anythingthat can keep scarring to a minimum.”

Adhesions represent a significantcomplication in secondary open heartsurgical procedures in that they make itdifficult to visualize and access theheart. The removal of these adhesions isan essential but tedious and risky proc-ess, which can extend the length of thesurgical procedure by up to 60 min.This additional time in surgery trans-lates into added cost as well as greaterrisk to the patient due to the extendedexposure to anesthesia.

“With adhesions, we have to cut through tough, fibrous tissue in

very delicate areas... this increases the amount of time a patient has

to be under anesthesia.”

Many other methods and materialshave been tried and tested but REPEL-CV looks very promising. “…if we use

anything we usually use a nonabsorbablemembrane made of Gore-Tex that weplace between the heart and the sternum,but it’s not ideal” says Lodge, anythingforeign that's left in the body can pro-voke an inflammatory response or inviteinfection and “that’s why the idea of anabsorbable film is so attractive.”

“the use of the REPEL-CV® dramatically reduced the

incidence of severe scarring.”

The study, presented at the Society ofThoracic Surgeons annual meeting,involved 103 infants at 15 institutionsaround the USA undergoing open heartsurgery that were expected to undergo asecond procedure. Half of the infants wererandomly assigned to the treatment groupwith the REPEL-CV and the others servedas controls. They found that the use of theREPEL-CV dramatically reduced the inci-dence of severe scarring and no side effectswere noted from the use of the film. Theproduct has not yet been approved by theFDA, although an application for approvalhas been accepted.

Sources: www.dukemednews.org/home

www.physorg.com

www.synthemed.com

Device: REPEL-CV® Adhesion Barrier

Patients (n): 103

Indication: Surgical scarring

About the News in BriefThe News in Brief highlights some of the most important events and launches in medical device research. The editorial team welcomessuggestions for timely, relevant items. If you have newsworthy information, please contact:

Rhian CunliffeAssistant Commissioning Editor, Expert Review of Medical Devices,Future Drugs Ltd, Unitec House,2 Albert Place, London N3 1QB, UKTel.: +44 (0)20 8371 6090; Fax: +44 (0)20 8343 2313;r.cunliffe@future-drugs.com