ABILITY TO UNDERSTAND THE CARPAL TUNNEL SYNDROME (CTS) ON ORTHOPAEDIC BOARD EXAMINATION

1.    The Candidate should be able to understand carpal tunnel syndrome or definition (CTS):

Carpal tunnel syndrome (CTS) is a symptomatic compression neuropathy of the median nerve at the wrist area with characterized physiologically by the increasing of pressure within the carpal tunnel and decreased function of the median nerve.

Note:The median nerve arises from the nerve roots of C6, C7 and T1 with sensory fibers innervate the palmar area of the thumb, index finger, middle finger and radial half of the ring fingers and the dorsal aspect of the tip of these fingers. The motoricbranches of the median nerve innervate the thenar muscles (abductor pollicisbrevis, opponenspollicis and flexor pollicisbrevis) and lumbrical muscle of the index and middle finger (fig. 3). 

The median nerve compression as a result of a reduction in tunnel volume or an increase in volume of tunnel contents that can lead to damage it (transient ischemic episode to microvascular disorders).Based on progressive form of CTS; there are three stages of CTS includes:

a.       Stage 1 of CTS (mild): Transient epineural ischemic episodes result in intermittent pain and paresthesia of the median nerve at the hand (nerve transmission disorders). The symptoms occur at night or following specific activities such as driving a car or holding a book or newspaper and others.

b.    Stage 2 of CTS (moderate): The complaintsareconstant paresthesias and tingling, related to disturb intraneural and epineural microcirculation concomitant with intrafascular edema. Electro-diagnostic tests usually reveal abnormal sensory conduction.

c.    Stage 3 of CTS (severe):Sensory and motoric functions are permanently damaged with atrophy of the thenar eminence or thenar muscles. Electro-diagnostic tests are abnormal,demyelinisation and axonal degeneration due to prolonged endoneural edema.

The incidence of CTS is 1-3 per 1000 per year cases and prevalence 50 cases 1000 cases in general populationat US. CTS can be caused by many different diseases, condition and events. It is characterized by patients as producing numbness, tingling, hand and arm pain and muscle dysfunction. CTSiscaused by systemic disease, local mechanical (chronic trauma) and disease factors.The prognosis of CTS is better result treatment in early diagnosis but untreated may worsen and progress to permanent sensory compromise and thenar paralysis, productivity loss and increase management cost.

1.      The Candidate should be able to identify the etiology and risk factorsof CTS:

Note:CTS are related to increased pressure on median nerve in carpal tunnel caused by many factors, includes traumaand chronic trauma such as specific occupations (repetitive motions, substance abuse) and also non-trauma for example:pregnancy, all age (peak incidence between the ages of 50 and 60), females gender are more common than male,  family history, hypothyroidism, diabetic, autoimmune diseases, rheumatological diseases, arthritis, obesity, renal disease, anatomic anomalyand infection disease.

2.      The Candidate should be able to present the history of CTS

Based on AAOS: Level of evidence: V and grade of recommendation: C

The Candidate guidance in appropriate question that should be asked during patient encounters to improve diagnosis

§  Ability to determine the complaints of hand numbness or hand/wrist pain and/or symptoms include:

a.       Duration

b.      Severity/character

c.       Location/radiation

d.      Pace of illness

e.       Previous treatment

f.        Lifestyle and activities

g.       Family history

Note:The sensory and weakness complaint are the most common presented by patient. Because of that, the Candidate must understand the classic complaints of CTS are not pathognomonic and patient usually present pain at night-time, tingling and paresthesias in the median nerve sensory distribution of the hand (fig.3). The complaints are often worse at nighttime and exacerbated by activities. Patients often complainare about thedifficulties of opening the bottle or driving a car or toothbrush/hairbrush and others.

3.      The Candidate should be able to perform the physical examinationof CTS

§  According to AAOS: Level of evidence: V and grade of recommendation: C

The Candidate guidance in appropriate question that should be asked during patient encounters to improve diagnosis

§  Ability to perform physical examination include:

a.    Look: Observation of deformity, swelling, atrophy, skin trophic changes(atrophy of thenar muscle)

b.    Feel: Tenderness,Sensory examination (two-point discrimination and others)

c.    Move: Range of motion of hand and wrist

d.    Special clinical tests: Pinch/grip strength,manual muscle testing of the upper extremity, Provocative tests (Phalen’s test: sensitivity 46-80 and specificity 51-91,Tinel’s sign: sensitivity 28-73 and specificity 44-95, median nerve compression test:sensitivity 04-79 and specificity 25-96, reverse Phalen’sinsufficient evidence).

e.    Discriminatory examination for alternative diagnosis eg. radiculopathy, neuropathy, pain syndrome, arthritis, tendonitis, vascular abnormalities, etc.

f.     Hand diagram

Note:Examination-based clinical diagnosis of CTS is necessary, but not always sufficient. The physician has to exclude cervical spondylosis and cervical disc herniation, therefore the Candidate must evaluate the cervical and upper extremity to exclude radiculopathy, brachial plexopathy of the upper trunk or lateral cord, or pronator syndrome and ulnar nerve compression syndrome

4.      The Candidate should be able to order investigation for CTS diagnosis

How the Candidate decides the CTS diagnosis and to exclude the differential diagnosis by investigations. The clinical diagnosis of CTS is principally established based on the patient’s history and physical examination findings (provocative clinical tests).

§  Ability to order and describe the x-rays (wrist and cervical spine) and laboratory for determination of risk factors such as pregnancy test, rheumatoid, diabetic, hypothyroidism, infection and autoimmune diseaseinvestigations

§  Ability to order and describe the electro-diagnostic test (nerve conduction study).

Note:Level of evidence V and grade of recommendation: C. This study can differentiate CTS from peripheral nerve problem (polyneuropathy, brachial plexopathy or cervical radiculopathy). The Candidate should obtain electro-diagnostic test if clinical and provocative are positive and surgical management is being considered (level of evidence II & III and grade recommendation: B). Although electro-diagnostic test findings are considered the most accurate single diagnostic test, false negatives and false positives are documented.

§  MRI or computerized axial tomography (CAT) investigation is rare use for diagnosis of CTS (level of evidence: V and grade of recommendation: C based on AAOS)

5.      The Candidate should be able to managethe CTS

Note:The management of CTS based on the severity of the disease. Severity of CTS is characterized by worsening clinical symptoms and clearly abnormal electromyography and nerve conduction tests.

Clinical evidence:

a.       Non-operative management is an option in patient diagnosed with CTS. Early surgery is an option when there is clinical evidence of median nerve denervation or if the patient elects to proceed directly to surgical treatment (AAOS recommend.1)

b.      We suggest another non-operative treatment to surgery if the current treatment fails to resolve the symptoms within two weeks to seven weeks (AAOS recommend.2)

c.       Before considering surgery, should be performed local steroid injection or splinting in treating patients with CTS, (AAOS recommend.3)

§  Ability to manage CTS conservatively

Note:The aim of non-operative management is an alleviating mechanical compression of median nerve at the level of the wrist area and treating any risk factors causes. Indication conservative management are mild and moderate of CTS, include nighttime splinting in neutral position of the wrist to minimize intra tunnel pressures, oral medication of NSAIDs, diuretics, and vitamin B6, ultrasound, iontophoresis, steroid and various exercises (stretching exercises can release compression in the tunnel, better joint posture that can decrease nerve compression and improving of the blood flow) and even yoga.

In UK recommendation: Conservative is a better result, if the symptoms are mild or moderate stages and are not progressing:

a.       Explain that symptoms may resolve within six months, especially in young patient (less than 30 years of age), the symptoms are unilateral and short duration symptoms, and precipitating factor in pregnancy women caused by fluid retention in the tunnel.

b.      Advice wearing a wrist splint for maintaining of the wrist at a neutral angle without applying direct compression. Any improvement should be apparent within 12 weeks of use.

c.       Acupuncture may be effective for pain relief in short relief in the short term, although there is no therapeutic benefit.

d.      Advice minimization of activities that exacerbate symptoms. Explain to people who work with computer keyboards that there is little evidence to suggest that modifications at their work place are likely to be of any help in relieving symptoms.

e.       Do not recommend the use of NSAIDs or diuretic drug

§  Ability to manage CTS operatively

The goals of surgery are an improving or relieving of the symptoms, function and quality of life. Standard surgery is a transection TCL by open incision or endoscopy procedures.

Note: Indication operative management are a failure of conservative management, CTS in advancing grade (stage 3) such as constant finger numbness, thenar weakness or atrophy or with thenar denervation by electro-diagnostic test. There are two surgery methods include arthroscopy/endoscopy and open carpal tunnel release (OCTR described by Sir James Learmonth in 1933 is a remaining of the mainstay procedure until now). Principally operative procedure is a transecting transverse carpal ligament (TCL) to increase the volume and decreasingof the pressure around the median nerve (fig. 4).

Success rate for surgery is range from 80-98%

§  Ability to perform OCTR procedure

Note: longitudinal skin incision approximately 2 cm along the thenar crease for OCTR methods (fig.5).

To avoid the occurrence palmar scar over the hamate hook and to minimize injury to the ulnar neurovascular bundle, the incision should be radial to hook of hamate bone (but not significantly more radially for avoiding injury palmar cutaneous branch of median nerve (PCBMN, fig.6)

After skin incision, expose the palmar fascia and incise it by scalpel then transver carpal ligament (TCL) became exposing.Transection should be done after TCL is exposed clearly. Routine neurolysis or epineurotomy during OCTR should be performed and the incision is closed by interrupted suture and then cover by a soft dressing.

§  Ability to perform postoperative care

Note: Formal rehabilitations are not necessary but principally the patient is asked for moving his/her fingers immediately after operation until 7-10 days for removal of suturing and patient usually returns to work normally within 2-6 weeks. Sometime postoperative splinting using for prevention the flexor tendon subluxation out of the tunnel canal

§  Ability to determine outcome and complications of CTS

Note: Eighty to ninety eight percent of the CTS symptoms may be alleviated with minimal complications by OCTR. OCTR complications includenerve (median, ulnar and digital) vessel and tendon lacerations. The incidence of infection is less than 1% and staphylococcus and streptococcusorganisms are the most common affecting.

a.       Firstly, some of CTS patients have an experiencing “Pillar” pain postoperatively (Pillar pain is defined as pain in the thenar or hypothenar regions due to a variety of factors such as scar sensitivity, neuroma of cutaneous nerve endings, changes in carpal arch dynamics or thenar and hypothener muscle origins, and/or decreased median nerve gliding).

b.      Secondly, the patient is still a persistent symptom of CTS caused by incomplete TCL release due to inadequate visualization especially at distal of the retinaculum. The others persistent symptoms of TCS are caused by cervical radiculopathy, brachial plexopathy or a pronator syndrome.

c.       Thirdly, an occult proximal lesion with persistent symptoms by producing a “double crush” phenomenon. Others causes are an intrinsic neuropathy especially in advance cases (stage 3) with preoperative of thenar denervation or systemic polyneuropathy such as diabetic patient.

d.      Fourth (lastly), persistent symptoms may be caused of untreated space lesion in the carpal tunnel for example tumor, ganglion or gout tophus and anatomy variation.

The rate of major complications for OCTR and endoscopy is low from 0.19% for endoscopy procedure (nerve problem such as neuropraxia, numbness, paraesthesia) and 0.49% for OCTR methods for example wound problem with infection, hypertrophic scarring, scar tenderness. The rate of repeat operations required does not differ significantly between two methods (OR 1.24, 95% CI: 0.50 to 3.07).

A younger age of patient and a shorter duration symptoms were associated with a better prognosis but the presence of bilateral symptoms or a positive Phalen’s test were associated with a poor prognosis

REFERENCES:

1.      AAOS (2007). Cinical Practice Guidline on the Diagnosis of Carpal Tunnel Syndrome. 6300 North River Road, Rosemont IL

2.      Ahcan U, Arnez ZM, Bajrovic F and Zorman P (2002). Surgical technique to reduce scar discomfort after carpal tunnel surgery. J Hand Surg 27: 821-827

3.      Fischer B, Gorsche R and Leake P (2004). Diagnosis, Causation and Treatment of Carpal Tunnel Syndrome: An Evidence-Based Assessment. Medical Services Workers’ Compensation Board-Alberta

4.      Rodner CM and Katarincic J (2006). Open Carpal Tunnel Release. Tech.Orthop 21: 3-11

5.      Singh I,Khoo KM, and Krishnamoorthy S (2005). Ann Acad Med Singapore. 23: 94-97

6.      Health Information and Quality Authority (2013). Health Tecnology Assessment of Scheduled Procedures. Release of Carpal Tunnel. Draft for Consultation.