I work as a patient coordinator at a clinic, and for the last 7 or 8
weeks I have been dealing with pain in my right forearm and wrist
while typing on the keyboard.  I went to my family's physician early
last week and he told me I had a combination of ulnar nerve irritation
(from improper resting of my forearms on the edge of my desk) and mild
case of carpal tunnel syndrome (CTS) (from extended periods on the
keyboard).  My doctor sent me to sent me to see a physical therapist
the day after my appointment; she agreed on the doctor?s diagnosis,
gave me some exercises to do, told me I could take ibuprofen to reduce
the inflammation, and fitted me with some wrist splints to wear while
at work.

It has been about 10 days since I was to the doctor, and my condition
seems to be getting better. The wrist splints really help reduce pain
and discomfort while I am at work and after.  I do feel a little
clumsy when wearing the wrist splints, but when I do not wear them the
pain is about 70% worse. In addition, I have made an effort to better
position myself while at the computer to prevent further injury.

While my condition seems to be improving now, I am really worried
about the condition of my hands down the road.  No one else in my
family has had problems with repetitive injuries.  My overall health
is great, but I am only in my mid 20?s and already have had two
repetitive strain injuries in my right hand.   The other injury was a
case of tendonitis on the extensor tendon of my middle finger (from
using a computer mouse for extended periods), which still bothers a
bit now and then (but I can live with it).  I am going to start dental
school this August, so I am worried that these problems with my right
hand could come back to haunt me later and possibly force me to leave
dental school, or a career as a dentist.

Is there a dentist, orthopedic surgeon, someone suffering from CTS, or
anyone else out there that can offer some advice/insight on my
situation?  Is this type of injury serious enough that I should
reconsider dental school and my dream to become a dentist, or is CTS
something that usually heals and goes away?  I understand vibration
from dental drills can cause CTS, so will I be more susceptible to
re-developing CTS since I already am dealing with it?  Is there enough
variation in dental surgery that repetitive strain injuries to the
hands are usually not a problem?  What occupational hazard
information/data is available on dentists?  What are most common
health related problems that cause practicing dentists to leave the
profession?

I am worried about my future right now.  I worked so hard to get
into dental school ? it was a dream come true.  Any help/insight would
be greatly appreciated.

Thank you,

Concerned Student

Dear Concerned Student,

Thank you for your question on CTS.  As you know, any information
provided is no substitute for direct medical evaluation or advice. 
From your description, you have been evaluated by a physician, which
is a good initial step.

Typically, rest of the effected area, physical therapy, and sometimes
a brace (to minimize further trauma) worn at night are the best first
line therapy for CTS.  For cases that don't respond or are more
severe, surgery is sometimes performed to release the pressure in the
carpal tunnel, which is compressing the nerves to the hand.

------------

Here are pictures of the anatomy:

This is from the Adam CTS website:
http://adam.about.com/reports/000034.htm
http://z.about.com/d/p/440/e/f/19250.jpg

http://sportsdrz.com/images/wrist.jpg

As someone about to embark on a career in the medical arena, you may
be interested in the details of the anatomy, to better understand how
CTS comes about.  From the eMedicine site cited below:

"The carpal canal is a fibroosseous tunnel at the wrist through which
9 flexor tendons and the median nerve pass. The carpal bones define
the dorsal aspect of the carpal canal and are shaped in a concave
arch. The palmar aspect of the carpal canal is defined by the TCL,
which bridges from one side of the carpal arch to the other. Both
intrinsic and extrinsic ligaments of the wrist and hand further
stabilize the carpal bones. The carpal canal is narrowest at the level
of the hook of the hamate, where the canal averages 20 mm in width.

 The TCL attaches to the scaphoid tuberosity and trapezial crest on
the radial side of the wrist and to the pisiform and hook of the
hamate on the ulnar side of the wrist... The TCL is 1.5 mm thick and
21.7 mm in length on average. Proximally, the TCL is a continuation of
the antebrachial fascia in the forearm, and, distally, the TCL
attaches to the fibers of the midpalmar fascia. The TCL is under
tension and helps to maintain the carpal arch. It serves as a
retinacular pulley for the flexor tendons. Cutting the TCL increases
the volume of the carpal canal. Cutting the TCL has also been
postulated to alter the kinematics of the carpus, risk bowstringing of
the flexor tendons, and decrease grip strength.

 A combination of the lateral (C6-7) and medial (C8-T1) cords of the
brachial plexus forms the median nerve. At the wrist and into the
palm, the median nerve divides into terminal motor and sensory
branches with some anatomic variability. The variability is due in
part to the branching point of the recurrent motor branch. An
extraligamentous pattern, with a branching point distal to the TCL, is
the most common. The recurrent motor branch also can divide from the
median nerve underneath the TCL in a subligamentous fashion and then
either wrap around the distal end of the TCL or pass directly through
the TCL to innervate the thenar muscles. Other less common patterns,
such as a branch point proximal to the TCL, exist as well. These
variations can have major surgical implications.

 The ulnar nerve is the other major motor and sensory nerve of the
hand. The ulnar nerve does not pass through the carpal canal but
instead through the Guyon canal located adjacent to the carpal canal
at the wrist. Division of the TCL will change the morphology of the
Guyon canal from triangular to ovoid."

---------------

The same source also discusses the etiology and pathophysiology of CTS:

"The etiology of CTS is multifactorial, with both local and systemic
factors contributing to varying degrees. Symptoms of CTS are a result
of median nerve compression at the wrist, with ischemia and impaired
axonal transport of the median nerve across the wrist. Compression
results from elevated pressures within the carpal canal. Elevated
pressures can develop within the carpal canal despite it not being a
separate closed compartment within the upper extremity. Direct
pressure or a space-occupying lesion within the carpal canal can
increase pressure on the median nerve and produce CTS. Fracture
callus, osteophytes, anomalous muscle bodies, tumors, hypertrophic
synovium, gout and other inflammatory conditions, and infection can
produce increased pressure within the carpal canal. Extremes of wrist
flexion and extension also elevate pressure within the carpal canal.

 Compression of a nerve affects intraneural blood flow. Pressures as
low as 20-30 mm Hg retard venular blood flow in a nerve. Axonal
transport is impaired at 30 mm Hg. Neurophysiologic changes manifested
as sensory and motor dysfunction are present at 40 mm Hg. Further
increases in pressure produce increasing sensory and motor block. At
60-80 mm Hg, complete cessation of intraneural blood flow is observed.
The carpal canal pressures in patients with CTS averaged 32 mm Hg
compared to only 2 mm Hg in control subjects.

 Pressure on the median nerve at a second site remote from the wrist,
termed the double crush syndrome, can further lower the median nerve's
pressure threshold for producing symptoms of CTS. If a nerve is
compressed at multiple sites, traction within the nerve with joint
motion may be produced. In addition to pressure, traction or stretch
has been demonstrated to produce alterations in intraneural
circulation. Elongation of only 8% can impair venular flow, and all
intraneural microcirculation can cease at 15% nerve elongation.

 Many systemic conditions are strongly associated with CTS. These
conditions may directly or indirectly affect microcirculation,
pressure thresholds for nerve conduction, nerve cell body synthesis,
and axon transport or interstitial fluid pressures. Perturbations in
the endocrine system, as observed in individuals with diabetes and
hypothyroidism and in women who are pregnant, are linked to CTS.
Conditions affecting metabolism (eg, alcoholism, renal failure with
hemodialysis, mucopolysaccharidoses) also are associated with CTS.

 The international debate regarding the relationship between CTS and
repetitive motion and work is ongoing. The Occupational Safety and
Health Administration (OSHA) has adopted rules and regulations
regarding cumulative trauma disorders. Occupational risk factors of
repetitive tasks, force, posture, and vibration have been cited.
However, the American Society for Surgery of the Hand has issued a
statement that the current literature does not support a causal
relationship between specific work activities and the development of
diseases such as CTS.

 Psychosocial and socioeconomic issues increasingly are being studied.
In a study of risk factors for CTS in women, the strongest link was a
previous history of another musculoskeletal complaint. Perceptions of
health and tolerance to pain also may influence the development of
CTS."

---------------------


A good, comprehensive resource on CTS is eMedicine.com.  There are
several articles available for free from a variety of viewpoints:

From an orthopedic surgeon (Dr. David Fuller at Cooper University
Hospital) and focuses on carpal tunnel release surgery:
http://www.emedicine.com/orthoped/topic455.htm

Another eMedicine page is written by the Associate Dean at Univ. of
Missouri, and is more broad in scope:
http://www.emedicine.com/EMERG/topic83.htm
As noted on this page, CTS is a very common disorder:
"CTS is the most frequently encountered peripheral compressive
neuropathy. The estimated lifetime risk of acquiring CTS is 10%, the
annual incidence is 0.1% among adults, and overall prevalence of CTS
is 2.7%"

The page goes on to mention the morbidity of not treating CTS:
"If untreated, CTS can result in thenar atrophy, chronic hand
weakness, and numbness in the median nerve distribution of the hand."

The above page also lists anti-inflammatory medications which are
helpful in the treatment of CTS.


The following eMedicine page is more focused on rehabilitation, which
includes physical therapy.  It is written by the Chief of the Physical
Medicine and Rehabilitation Department at the University of Alberta
(Dr. Nigel Ashworth):
http://www.emedicine.com/pmr/topic21.htm

In terms of physical and occupational therapy, this site recommends the following:
"Rehabilitation Program: 

	? 	 Physical Therapy:  Given that CTS is associated with low aerobic
fitness (and increased BMI), it makes inherent sense to provide the
patient with an aerobic fitness program. Stationary biking, cycling,
or any other exercise that puts strain on the wrists probably should
be avoided.

 The use of modalities (eg, ultrasound, phonophoresis, iontophoresis)
may provide relief in some patients. Interestingly, it may be possible
to enlarge the carpal tunnel by specific stretching techniques. Such
an exercise program may provide a new noninvasive treatment for CTS in
the future.
	? 	 Occupational Therapy: Work site ergonomic assessment may help to
reduce potentially exacerbating factors (eg, poor posture, excessive
force). Manufacture of a wrist-hand orthosis with wrist joint in
neutral (to be worn at nighttime for a minimum of 3-4 weeks) is one of
the best evidence-based conservative treatments for CTS. A specific
stretching/strengthening program for the hand and wrist may be useful
in improving strength and dexterity (particularly following surgical
treatment), although it can exacerbate symptoms. Massage and/or nerve
glide techniques offer no proven benefit."

This site also discusses prognosis:

"Prognosis: 

	? 	CTS appears to be progressive over time (though with considerable
fluctuations week to week) and can lead to permanent median nerve
damage. Whether any conservative management can prevent progression is
unclear. Even with surgical release, it appears the syndrome reoccurs
to some degree in a significant number (possibly up to one third after
5 years).
	? 	Initially, approximately 90% of mild-to-moderate CTS cases respond
to conservative management. Over time, a number progress to requiring
surgery.
	? 	Patients with CTS secondary to underlying pathology (eg, diabetes,
wrist fracture) tend to have a less favorable prognosis than those
with no apparent underlying cause.
	? 	Patients with normal EDX studies consistently have much less
favorable operative outcomes (and more complications) than those with
abnormalities on EDX. Axonal loss on EDX indicates less favorable
prognosis."

(EDX: electrophysiologic testing, including nerve conduction studies, etc.)


If you are interested, eMedicine also has information on the
radiological imaging of CTS:
http://www.emedicine.com/radio/topic135.htm

The eMedicine patient-oriented CTS page can be found here:
http://www.emedicinehealth.com/articles/5013-1.asp


-------------------------

More specific to dentistry, there are several articles that address
the questions you raise:

This review article discusses vibration's role in CTS in the dental office:
Szymanska J. Dentist's hand symptoms and high-frequency vibration.
[Review] [33 refs] [Journal Article. Review. Review, Tutorial] Annals
of Agricultural & Environmental Medicine. 8(1):7-10, 2001.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11426919
Here is the abstract:
"The paper discusses characteristics of mechanical vibration as well
as the mechanisms of vibration syndrome. Analysis of the relationship
between the high-frequency vibration and the typical symptoms in the
hands of the dentists is presented. Suggestions have been offered on
how to limit exposure to vibration in the hands of dentists"
The free full-text article is available here:
http://www.aaem.pl/pdf/aaem0102.pdf
The article goes on to discuss suggested techniques for minimizing CTS
in dentists at the end of the article.


Further references to vibration-related CTS can be found here:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Display&dopt=pubmed_pubmed&from_uid=11426919


Another good journal article on CTS among dentists can be found here:
Hamann C. Werner RA. Franzblau A. Rodgers PA. Siew C. Gruninger S.
Prevalence of carpal tunnel syndrome and median mononeuropathy among
dentists.[see comment]. [Journal Article] Journal of the American
Dental Association. 132(2):163-70; quiz 223-4, 2001 Feb.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11217588

This article is not available for free online, however the abstract is available:
"BACKGROUND: The authors undertook a study to determine the prevalence
in dentists of abnormal sensory nerve conduction and/or symptoms of
carpal tunnel syndrome, or CTS, the most common nerve entrapment
syndrome. METHODS: In a cross-sectional study, dentists (n = 1,079)
were screened during the American Dental Association's Annual Health
Screening Program in 1997 and 1998 by means of standard
electrodiagnostic measures in the dominant hand and a self-reported
symptom questionnaire. The authors diagnosed a median mononeuropathy
from a 0.5- or 0.8-millisecond, or ms, prolongation of the median
sensory-evoked peak latency compared to the ulnar latency. They
diagnosed CTS if the subject also had accompanying symptoms of
numbness, tingling or pain. RESULTS: Thirteen percent of screened
dentists were diagnosed with a median mononeuropathy (using a 0.5-ms
prolongation as the criterion), but only 32 percent of these had
symptoms consistent with CTS (4.8 percent overall). When the 0.8-ms
prolongation was used as the electrodiagnostic criterion, only 2.9
percent (overall) were diagnosed with CTS. People with diabetes,
rheumatoid arthritis and obesity were more likely to have a median
mononeuropathy. CONCLUSIONS: The prevalence of symptoms consistent
with CTS in the dominant hand among dentists was higher than the
prevalence in the general population. However, when electrodiagnostic
confirmation is added, the prevalence of CTS was nearly the same as
that among the general population. CLINICAL IMPLICATIONS: Early
recognition of CTS can lead to more effective management. Education
regarding ergonomic risk factors can be an effective preventive
measure."

For a reprint of the above article, you can contact Dr. Hamann
(amann@SmartPractice.com) at the Univ. of Michigan.

Here is another article on the same topic from the above group:
Werner RA. Hamann C. Franzblau A. Rodgers PA. Prevalence of carpal
tunnel syndrome and upper extremity tendinitis among dental
hygienists. [Journal Article] Journal of Dental Hygiene. 76(2):126-32,
2002.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12078576
Here is the abstract:
"PURPOSE: This study was undertaken to determine the prevalence of
carpal tunnel syndrome (CTS) and upper extremity (UE) tendinitis among
dental hygienists. METHODS: In a cross-sectional study dental
hygienists (n = 305) were screened using sensory nerve conduction, a
focused physical examination of the UE, and a symptom questionnaire.
CTS was diagnosed if the subject had slowing of the median nerve at
the wrist and symptoms of numbness, tingling of pain in the median
distribution. Localized tendinitis of the UE was diagnosed if the
subject had focal symptoms and associated findings on physical
examination. RESULTS: Three percent of the participating dental
hygienists were diagnosed with CTS. Thirteen were diagnosed with
shoulder tendinitis, while 6% had a tendinitis of the elbow and 7% had
tendinitis of the hand or wrist. Twenty-eight percent had a diagnosis
of some UE tendinitis or CTS. CONCLUSIONS: The prevalence of hand and
finger symptoms in the dominant hand among dental hygienists in this
study was high, but the prevalence for CTS was nearly the same as the
general population. There was a high rate of UE tendinitis noted
within this population."

You could likely obtain a copy of the reprint of this article from Dr.
Hamann as well.


Here are some other articles dealing with CTS in dentists that you may
find interesting:

White P. Ergonomics in a dental office--an oxymoron?. [Journal
Article] Journal of the Massachusetts Dental Society. 51(2):24-6,
2002.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12108121

Chin DH. Jones NF. Repetitive motion hand disorders. [Review] [41
refs] [Journal Article. Review. Review, Tutorial] Journal of the
California Dental Association. 30(2):149-60, 2002 Feb.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11883427

Mito RS. Fernandez K. Why is ergonomics an issue in dentistry?.
[Journal Article] Journal of the California Dental Association.
30(2):133-4, 2002 Feb.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11881957

Pollack-Simon R.  Ergonomics in the dental office.  Dent Today. 2000 Jun;19(6):92-5
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12524799

Gerwatowski LJ, McFall DB, Stach DJ.  Carpal tunnel syndrome. Risk
factors and preventive strategies for the dental hygienist.  Dent
Health (London). 1992 Oct-Nov;31(5):5-10.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=1291352

-----------

In summary, a significant number of dentists suffer from some type of
CTS and practice preventative and physical therapy-based techniques to
minimize it's effect and progression.  For this reason, I would not
advise against pursuing dentistry, however treating CTS (as you are
doing) is important so that it does not limit your manual ability and
dexterity in the future.

I hope this information was useful.  Please feel free to ask for clarification.

Best,
            -welte-ga