Carpal tunnel

2. Carpal Tunnel Syndrome

3. Definition
•Sign and symptoms secondary to compression
of the median nerve in the carpal tunnel

4. History
•CTS First described by
Sir James Paget 1854
•First CTR performed
Sir James Learmonth 1933
•Popularised by Phalen in the 1950s with a series of
articles
•Introduction of endoscopic release 1985-1987
–Dr Agee, Dr Chow, Dr Okutsu

5. Anatomy - median nerve

6. Attachment of the transverse carpal ligament
Content of the carpal tunnel
Relationship with the Guyon’s tunnel

7. Anatomy - Carpal Tunnel
•The bony borders are: radially, the tubercle of the scaphoid and the
tubercle of the trapezium; ulnarly the triquetrum, pisiform and hook of
the hamate. The lunate lies in the floor of the tunnel.
•Nine tendons run through the tunnel: the 4 FDS, the 4 FDP, and FPL. FCR
runs in a separate fascial compartment on the radial side of the tunnel.
The middle and ring FDS tendons are superficial to the index and little
finger FDS tendons. The FDS and FDP tendons all share a common sheath;
the tendons appear to be invaginated into the sheath from the radial side.
The FPL tendon has its own synovial sheath.
•The recurrent motor branch can be extraligamentous; subligamentous;
transligamentous. Rarely, it can take origin from the ulnar side of the
median nerve, and it can come to lie on top of the transverse carpal
ligament.

8. Anatomy - PCB median nerve

9. Extra-ligamentous
Sub-ligamentous
Trans-ligamentous
The recurrent motor branch
of the median nerve

10. Microstructure of the median nerve in the
carpal tunnel
•The nerve is composed of 6-40 fascicles with
an average of 24. Epineurial tissue makes up
around 42% of the nerve.
•Sensory fibres outnumber motor fibres 9:1.
The motor nerve fibres are situated anteriorly.

11. Physiology
•Excursion of the nerve
– with flexion/extension is 7-14mm at the wrist
– 5-7mm at the elbow.
•Resting pressure in normal patients is 2.5mmHg.
–Full flexion or extension increases the pressure to 30mmHg in normal
patients
–90-100mmHg in patients with CTS
–Contraction of finger and thumb flexors may increase pressure 3-6
times above resting values.
•Reduced epineural blood flow is the earliest manifestation of
nerve compression
–and may occur at a pressure of 20-30mmHg.
–Reduced axoplasmic transport occurs at pressures of 30mmHg.

12. Pathophysiology of CTS
•Night numbness is caused by a number of factors:
•Horizontal position results in a redistribution of fluid
to the upper limbs
•Drainage by the action of the muscle pump is
diminished
•There is a tendency towards wrist flexion at night
•The blood pressure drops during late night and early
morning, resulting in decreased perfusion pressure

13. Epidemiology
•Carpal tunnel syndrome is the most common
compression neuropathy.
•Median age is 51.
•Women are affected 4:1
•More common in industrialized societies.
•High rate of bilateral compression.
•More common in the dominant arm.
•50% associated with Raynaud’s phenomenon.

14. Aetiology
•Reduction in the size of the carpal tunnel:
–Trauma
–Acromegaly
–osteoarthritis
•Increase in the volume of the contents of the carpal tunnel:
–Inflammation: Nonspecific tenosynovitis of the flexor
tendons; RA; gout; amyloid.
–Swellings: ie. Ganglia; lipoma; tumour.
–Endocrine abnormalities: ie. Pregnancy; diabetes; thyroid
disease.
•Congenital developmental conditions
–Persistent median artery
–Abnormal muscle bellies - eg. FDS, palmaris profundus
–Proximal or hypertrophied lumbricals

15. Symptoms
•Nocturnal numbness and paraesthesias almost
pathoneumonic
–This is because of redistribution of blood from the legs
while the patient is recumbent, with dilation of blood
vessels in the carpal tunnel.
–Shaking the hand gets the blood out of the dilated vessels.
•The pain should radiate only to the elbow.
•The patient may complain of dropping things.

16. Signs
•Numbness doesn’t have to be exactly anatomical but there should be a
big difference between the thumb and little finger.
–Numbness often affects the middle finger first then the thumb and
index.
–The palmar sensory branch should be spared so there should be
normal sensation over the thenar eminence.
•Thenar wasting is a late sign and implies you have missed the boat.
•Phalen’s sign may be positive with either volar flexion (Phalen’s volar test)
or dorsiflexion (Phalen’s dorsal test). Overall sensitivity of 75%, specificity
of 0.47.
•Tinel’s sign has a sensitivity of 0.60 and a specificity of 0.67.
•Durkan’s direct median nerve compression test is the most sensitive
(0.87) and specific (0.90).

17. Phalen’s Test

18. Durkan’s Test

19. Nerve Conduction Studies
•The main benefit of NCS is to provide objective evidence for
the diagnosis.
•False negative rate of 8%. (These patients have symptoms
and respond to carpal tunnel release but have normal NCS).
•EMG evidence of denervation of the thenar muscles provides
evidence of the severity of compression.
•Discrepancy between clinical findings and NCS
–Interestingly, no consensus could be reached regarding
the patient with classic/probable symptoms without
abnormal NCS findings. This is the group where diagnosis
is often debated between hand surgeons and neurologists.

21. DDx
1.Pronator syndrome:
–compression by the ligament of Struthers, supracondylar process, bicipital
aponeurosis, within pronator teres and under FDS arch. Hand numbness and
nocturnal pain and numbness is rare.
1.Anterior interosseous syndrome
2.Brachial neuritis
3.Thoracic outlet syndrome
4.Cervical radiculopathy
5.RSD
6.Raynaud’s phenomenon
7.TIA

22. Treatment: Non-surgical
•Only if no sign of motor damage.
•Reduce oedema with diuretic or steroid.
•Splint to reduce nocturnal flexion – splint in
neutral.

23. Steroid Injection
•Transient relief occurs in 80% of patients after steroid injection
•But only 22% of patients with steroid injections are pain free at 12 months
(These patients were also splinted).
–It is most useful early in the disease, when there has been less than 1
yr of symptoms
–there is no weakness or thenar atrophy
–less than 2ms prolongation of distal motor and sensory latencies.
•Technique of injection:
– a 22-gauge needle is introduced between FCR and PL
–angled dorsally and distally at 45 degrees
–It is advanced until it reaches the floor of the tunnel, and then
withdrawn 5mm
–A water soluble preparation is used
• e.g. dexamethasone acetate plus lignocaine
•if any immediate paraesthesias occur the injection is stopped.

24. Non-surgical treatment (other than steroid
injection) for carpal tunnel syndrome
[Review] Volume (1), 2006, [no page #]
The Cochrane Library, Copyright 2006, The Cochrane Collaboration
O'Connor, D; Marshall, S; Massy-Westropp, N
Date of Most Recent Update: 15-August-2005
Implications for practice:
•Moderate evidence shows significant short-term benefit from
oral steroids.
•Limited evidence shows significant short-term benefit from
splinting
•yoga and carpal bone mobilization do not produce significant
benefit.

25. Surgical Treatment
•Open Carpal Tunnel Release
–Open technique
–Limited incision technique
•Endoscopic Carpal Tunnel Release(1985)
–Two incision technique Dr James Chow (Southern Illinois)
–Distal single incision technique Dr Michael Murphy (John
Hopkins Univ, Baltimore)
–Proximal single incision technique Dr John Agee
(Sacramento, California)

26. Open Carpal Tunnel Release
-Surgical Landmarks

27. Open carpal tunnel
release
-Structures to avoid
1.Palmar cutaneous
br of median nerve
2.Superficial palmar
arch

28. Open Carpal Tunnel Release

29. Postoperative course and results for Open
CTR
•Grip strength returns to normal in 3 months.
•Surgery is most successful when done early; Patients with
intermittent numbness do better than patients with constant
numbness.
•Overall excellent results in 80% (Mayo clinic). 5% have
worsened function.
•MRI shows a 20-30% increase in the carpal tunnel volume
after surgery. MRI also shows that Guyon’s canal enlarges
after carpal tunnel release.
•Measurement of pressures within the carpal tunnel before
and after release demonstrate marked decreases in resting
pressures after release of the ligament.

30. Endoscopic Techniques - CTR
•Two incisions
•Distal one incisions
•Proximal one incisions

31. Two incisions technique by James Chow
Slotted tube technique
Adv: Visualise the distal and proximal margin of TCL
Disadv: Two portals. One portal in the palm

32. Single distal portal endoscopic technique
Advantage: Visualise the superficial arch and the distal margin of TCL
Disadvantage: the incision is in the palm

33. Single distal portal endoscopic technique

34. single proximal
portal technique
-John Agee from
Sacrimento
California
-The equipmenmt is
manufactured by Microaire
Pty Ltd.

35. Endoscopic carpal
tunnel release
-single portal
technique

36. Outcome:
Endoscopic vs Open

37. The Cochrane Database of Systematic Reviews
Surgical treatment options for carpal tunnel syndrome [Review]
Volume (1), 2006, [no page #]
Scholten, R; Bouter, LM; Gerritsen, A; Uitdehaag, BM; de Vet,
HCW; van Geldere,
D
Date of Most Recent Update: 17-August-2005
Cochrane Neuromuscular Disease Group.
Dr. Rob Scholten, Director, Dutch Cochrane Centre, Academic Medical Center, Room
J1B - 108-1, P.O. Box 22700, AMSTERDAM, 1100 DE, NETHERLANDS. Phone: [phone]
5602, Fax: [phone], E-mail: [email protected], N
Background: Carpal tunnel syndrome is a common disorder, for which several
surgical treatment options are available.
Objectives: To compare the efficacy of the various surgical techniques in
relieving symptoms and promoting return to work and/or activities of daily
living and to compare the occurrence of side-effects and complications, in
patients suffering from carpal tunnel syndrome.
Search strategy: We updated the searches in 2003. We conducted computer-aided
searches of the trials register of the Cochrane Neuromuscular Disease Group
(searched in July 2003), the Cochrane Central Register of Controlled Trials (The
Cochrane Library, Issue 2, 2003), MEDLINE (January 1966 to August 2003), EMBASE
(January 1980 to August 2003) and tracked references in bibliographies.
Selection criteria: Randomised controlled trials comparing various surgical
techniques for the treatment of carpal tunnel syndrome.
Data collection and analysis: Two reviewers performed study selection,
assessment of methodological quality and data abstraction independently of each
other.
Main results:
Twenty-three studies were included in the review. The methodological quality of
the trials was fair to good. However, the application of allocation concealment
was mentioned explicitly in only one trial. Many studies failed to present the
results in sufficient detail to enable statistical pooling. Pooling was also
impeded by the vast variety of outcome measures that were applied in the various
studies.
None of the existing alternatives to standard open carpal tunnel release seem to
offer better relief from symptoms in the short- or long-term. There was
conflicting evidence about whether endoscopic carpal tunnel release resulted in
earlier return to work and/or activities of daily living than open carpal tunnel
release.
Conclusions: There is no strong evidence supporting the need for replacement of
standard open carpal tunnel release by existing alternative surgical procedures
for the treatment of carpal tunnel syndrome.
-Reviewed 23 studies RCT
-Good methodology
-Pooling of results was not possible
because of differing outcome
measures
-alternatives to open CTR does not
offer better relief of symptoms
-Result of early return to work with
endoscopic mean is conflicting
Conclusion: No evidence to
support replacement of open CTR

38. A Systematic Review of Reviews Comparing
the Effectiveness of Endoscopic and Open
Carpal Tunnel Decompression
Achilleas Thoma, M.D., M.Sc., Karen Veltri, M.Sc., Ph.D., Ted Haines, M.D., M.Sc.,
and Eric Duku, M.Sc.
Hamilton, Ontario, Canada
(Plast. Reconstr. Surg. 113: 1184, 2004.)
Controversy persists regarding the benefit of endoscopic
carpal tunnel release compared with open carpal
tunnel release for pain, numbness, strength, return to
work and function, scar tenderness, and complications.
For surgeons, a recommended first source of information
on treatment effectiveness is a review of high-methodologic-
quality articles. This review of reviews was undertaken
to answer this clinical question regarding these outcomes.
Cochrane, MEDLINE, EMBASE, CINAHL, and Health-
STAR databases were searched using the key words “endoscopic
carpal tunnel,” with limits “review or overview”
and dates from 1989 to present. Five key journals were
hand-searched. Any review with a reference to at least one
randomized controlled trial that compared endoscopic
carpal tunnel release to open carpal tunnel release was to
be included. Two reviewers independently scanned titles
and abstracts for potential relevance. Selection as relevant
was confirmed through a review of full texts. Disagreements
were resolved through discussion and consensus.
The selected reviews were assessed for methodologic quality
on the basis of the scale of Hoving et al. Of 48 articles
initially identified, seven pertinent reviews were selected.
Of these seven, three reviews of high methodologic quality
concurred that there is no difference between the two
techniques in symptom relief and that the evidence is
conflicting for return to work and function. The risk of
permanent median nerve injury does not differ between
the techniques. The reviews indicated that the endoscopic
carpal tunnel release technique is worse in terms of reversible
nerve injury but superior in terms of grip strength
and scar tenderness, at least in short-term follow-up. Several
trials have not been incorporated in these reviews and
statistical pooling has not been conducted. Further systematic
review with meta-analysis may permit more definitive
conclusions about the relative effectiveness of these
two techniques, particularly with regard to return to work
and function.
Controversy between the two techniques
Reviewed articles from 1989-2002
48 articles on the topic
7 articles are pertinent to the question
3 of high quality methodology
-both techniques relief symptoms
-conflicting result regarding return to work
and function
-no difference in the risk of median n. injury
-endoscopic has worse reversible nerve
injury
-Endoscopic has superior grip strength and
and less scar tenderness

39. Point for discussion
•ECTR & OCTR ONLY relieve the mechanical
component of the pathology
•i.e. that they do not address the biochemical,
pathophysiology, endocrine or hormonal
aspects of the disease
•i.e. we can perform a brilliant CTR but if the
nerve has more than a mechanical problem
then the pt will not get a full relief.

40. Point for discussion
•When Durkan’s, Phalen’s & Tinel’s tests are all
negative, that the nerve is "no longer able to
be irritated"
•ie that it has undergone some pathological
change, such as intra-neural fibrosis or other,
that prevents a positive response.

41. Complications
•Early
–Transection of the median nerve or the superficial arch
–Haematoma
–Pain, swelling and stiffness
–Recurrent Branch injury
–Infection
•Late
–RSD
–Hypertrophic scar
–Median nerve neuritis
–Palmar fasciitis
–Fibrosis of carpal tunnel
–Recurrence
•Revision carpal tunnel release
–Only 25% of patients have complete relief of symptoms. 25% have no relief.
The rest have partial relief.