Needed Research to Needed Research to Improve Care for Improve Care for

People with Trigeminal People with Trigeminal Neuropathic PainsNeuropathic Pains

Donald Nixdorf, DDS MSAssistant Professor

University of Minnesota

nixdorf@umn.edu

What do YOU think?

• Education– More Awareness in Primary Care (DDS &

MD)

• Better medications & treatments– More effective– Less side-effects

• Improved Diagnostic Criteria– Based on WHAT?

Knowledge of the Knowledge of the MechanismsMechanisms

H.M.S. Salisbury James Lind (1716-1794)

“The number of seaman in time of war who died of shipwreck, capture, famine, fire or sword, are but of inconsiderable in respect of such as are destroyed by the ship diseases, and by the usual maladies of intemperate climates.” – Dr. Lind, 1753

Symptoms of Scurvy

• lethargy

• irritability

• weight loss

• aching of the joints

• bleeding under the skin and nails

• swollen and bleeding gums

• spontaneous bruising

• wounds slow to heal

Scurvy: Timeline 1601 - James Lancaster (sea captain) records lemon juice

as protective against scurvy

1744 - British Admiral George Anson completes trip around the world in the Centurion . Over half of the 2,000 sailors die from scurvy

1747 - Lind’s experiment on the HMS Salisbury

1754 - Lind publishes “A Treatise of the Scurvy”

1775 - Captain James Cook completes historic voyagesSailors remained free from scurvy

1795 - British Navy supplies daily ration of lime or lemon juice

1932 - Waugh and King (U of Pittsburgh) and Szent Gyorgyi (Hungary) isolate and synthesize vitamin C

DiseaseDiscoverer of

preventive measure

Year of discovery of preventive measure

Year of discovery of causal agent

Agent

Scurvy J. Lind 1753 1932 Ascorbic acid

Scrotal cancer P. Pott 1775 1933 Benzo(a)pyrene

Smallpox E. Jenner 1798 1958 Orthopoxvirus

Puerperal fever I. Semmelweis 1847 1879 Streptococcus

Cholera J. Snow 1849 1893 Vibrio cholerae

Bladder cancer L. Rehn 1895 1938 2-Naththylamine

Yellow fever W. Reed et al 1901 1928 Flavivirus

Oral cancer R. Abbe 1915 1974 N-

nitrosonomicotine

Wynder EL. Am J Epidemiol 1994; 547-549

What we are looking for…

Care Provider

Scientist

Epidemiologist

What am I going to do…

• Functional Magnetic Resonance Imaging

ffMRIMRI

Acquisition parameters:TR/TE = 50/3.5 ms, readout bandwidth 20 kHz, FOV 20 x 11.2 x 2.5 mm, matrix 384 x 216 x 16, 16 averages,Acquisition time 2:53 min/scan, total time 46:08 min. The image was reconstructed 2x zero-filling, producing a reconstructed resolution of 26 x 26 x 78 mm.

High Resolution (post-MION) acquisition

Bolan, Yacoub, Garwood, Ugurbil, Harel NeuroImage 2006

Vessel Classification 3D Vessel Reconstruction

blue = veinred = artery

Bolan, Yacoub, Garwood, Ugurbil, Harel NeuroImage 2006

Maximum Intensity Projections (MIP)

MIP of the 3D subtraction (Pre/Post MION)

Bolan, Yacoub, Garwood, Ugurbil, Harel NeuroImage 2006

First human images at 9.4 Tesla

Vaughan et al., MRM 2006

Definitions

Neuropathic Pain needs to fulfill the following criteria:

1) Pain presents in a neuranatomically defined area

2) History of a relevant disease or lesion in the nervous system (dental procedures)

3) Partial or complete sensory loss in all or part of the painful area

4) Confirmation of the lesion or disease by a specific test (i.e. surgical evidence, imaging, neurophys., biopsy)

1. Does persistent pain arise from surgery?

2. What are the factors that would put some patients at higher risk for developing persistent pain than others ?

3. What are the human neuroanatomical & functional mechanisms involved in this type of pain?

…multiple other research questions & steps… What are viable interventions and when

should they best be applied ? (pre-op, intra-op & post-op)

Procedures performed within U.S. (in 100,000/yr)

15,838

40,036

55,874

45,023

0 15,000 30,000 45,000 60,000

All General Surgeries

Nose/Mouth/Pharynx

All Dental Surgeries

Tooth Extractions

Root Canal Therapies

Data from the CDC (2004) & American Dental Association (1999)

309

Take Home • 30% get persistent pain

• 10% are severely affected

Kehlet et al, 2006

in Lancet

Type of Procedure

# Studies in Literature

Post-op nerve

damage

Persistent pain at 12 months

#’s seen in tertiary

pain clinics

BSSO 4 ~75%

(60-88%)

~4%

(0-6%)

some

3rd Molar Extraction

6 ~5%

(0.5-8%)

<1%

(0-0.9%)

few

Root Canal Therapy

4 unknown ~5%

(3-13%)

several

SUMMARYDental Procedures

Procedures performed within U.S. (in 100,000/yr)

792 (5%)

400 (1%)

1,676 (3%)

0 15,000 30,000 45,000 60,000

All General Surgeries

Nose/Mouth/Pharynx

All Dental Surgeries

Tooth Extractions

Root Canal Therapies

Data from the CDC (2004) & American Dental Association (1999)

93 (30%)

13,406 (30%)

Pain & OralPain & OralHealth Quality of Life:Health Quality of Life:

Measuring Success of Root Measuring Success of Root Canal TherapyCanal Therapy

Prospective cohort evaluating non-surgical root canal therapy 1 year after treatment

Aims:1) Determine incidence of persistent pain at 1 year

2) Assess the burden on the individual

3) Evaluate the risk factors associated with developing this type of pain

Laboratory Clinical Practice-based Community- research trials research based

in academic research settings

Why participate in practice-based research networks?

1. Generalizability

2. Sample size