**6. Median nerve**

#### **6.1. Anatomy**

The median nerve is formed in the axilla by a branch each from the medial and lateral chords of the brachial plexus, receiving fibers from C6, C7, C8 and T1 roots. It arises anterior to the axillary artery, descending distally through the arm lateral to the brachial artery till it reaches the medial aspect of the arm. It is important to know that the median nerve has no branches above the cubital fossa. It enters the cubital fossa lateral to the brachialis tendon passing between the two heads of the pronator teres giving off the anterior interosseus branch (Figure 1).

**Figure 2.** Branches and supplied muscles by the median nerve in the forearm.

the lateral aspect of the fourth digit. (Figure 3).

**6.3. Pronator teres syndrome (Proximal compression)**

**6.2. Median nerve entrapment**

techniques for their release.

*6.3.1. Sites of compression*

supracondylar process of humerus).

Finally, it enters the hand through the carpal tunnel, running beneath the transverse carpal ligament, superficial to nine tendons: four of the flexor digitorium superficialis, four of the flexor digitorium profundus and one of the flexor pollicis longus. Distally it supplies the thenar eminence muscles and the lateral two lumbricalis, providing sensation to the first 3 digits and

Compression Neuropathies http://dx.doi.org/10.5772/55316 107

There are three well-described entrapment syndromes involving the median nerve or its branches, namely pronator teres syndrome, anterior interosseous syndrome and carpal tunnel syndrome according to the level of entrapment. Each one of these syndromes presents with different clinical signs and symptoms, electrophysiologic results and requires different

This is the most proximal compression site of the median nerve. It is due to compression of the median nerve as it passes through pronator teres. It may also be compressed upon the lacertus fibrosus (fascial sheet attached to biceps tendon), at the arched origin of the flexor digitorium superficialis or at the ligament of Struthers (connects medial epicondyle with a

**Figure 1.** Median nerve descending lateral to brachial artery, giving off the anterior interosseus branch between the two heads of the pronator teres.

The nerve continues in the forearm between the flexor digitorium profundus and flexor digitorium superficialis, giving off above the wrist the palmar cutaneous branch that supplies the skin of the central portion of the palm. In the forearm it supplies the pronator teres, flexor carpi radialis, flexor digitorium superficialis and profundus, flexor pollicis longus and pronator quadratus [6] (Figure 2).

**Figure 2.** Branches and supplied muscles by the median nerve in the forearm.

Finally, it enters the hand through the carpal tunnel, running beneath the transverse carpal ligament, superficial to nine tendons: four of the flexor digitorium superficialis, four of the flexor digitorium profundus and one of the flexor pollicis longus. Distally it supplies the thenar eminence muscles and the lateral two lumbricalis, providing sensation to the first 3 digits and the lateral aspect of the fourth digit. (Figure 3).

#### **6.2. Median nerve entrapment**

**6. Median nerve**

two heads of the pronator teres.

pronator quadratus [6] (Figure 2).

The median nerve is formed in the axilla by a branch each from the medial and lateral chords of the brachial plexus, receiving fibers from C6, C7, C8 and T1 roots. It arises anterior to the axillary artery, descending distally through the arm lateral to the brachial artery till it reaches the medial aspect of the arm. It is important to know that the median nerve has no branches above the cubital fossa. It enters the cubital fossa lateral to the brachialis tendon passing between the two heads of

106 Peripheral Neuropathy - A New Insight into the Mechanism, Evaluation and Management of a Complex Disorder

**Figure 1.** Median nerve descending lateral to brachial artery, giving off the anterior interosseus branch between the

The nerve continues in the forearm between the flexor digitorium profundus and flexor digitorium superficialis, giving off above the wrist the palmar cutaneous branch that supplies the skin of the central portion of the palm. In the forearm it supplies the pronator teres, flexor carpi radialis, flexor digitorium superficialis and profundus, flexor pollicis longus and

the pronator teres giving off the anterior interosseus branch (Figure 1).

**6.1. Anatomy**

There are three well-described entrapment syndromes involving the median nerve or its branches, namely pronator teres syndrome, anterior interosseous syndrome and carpal tunnel syndrome according to the level of entrapment. Each one of these syndromes presents with different clinical signs and symptoms, electrophysiologic results and requires different techniques for their release.

#### **6.3. Pronator teres syndrome (Proximal compression)**

#### *6.3.1. Sites of compression*

This is the most proximal compression site of the median nerve. It is due to compression of the median nerve as it passes through pronator teres. It may also be compressed upon the lacertus fibrosus (fascial sheet attached to biceps tendon), at the arched origin of the flexor digitorium superficialis or at the ligament of Struthers (connects medial epicondyle with a supracondylar process of humerus).

#### *6.3.2. Diagnosis*

The onset is insidious and is suggested when the early sensory disturbances are greater on the thumb and index finger, mainly tingling, numbness and dysaesthesia in the median nerve distribution. Patients will also complain of increased pain in the proximal forearm and greater hand numbness with sustained power gripping or rotation because these movements tighten the fibrous origin of the superficial flexor muscles beneath which the median nerve passes. There is no nocturnal preference.

**6.4. Anterior interosseous syndrome**

the deep level of the anterior compartment of the forearm.

muscle (accessory head of flexor pollicis longus).

The anterior interosseous nerve classically innervates these muscles: flexor pollicis longus, pronator quadratus and the radial half of flexor digitorium profundus. These muscles are in

Compression Neuropathies http://dx.doi.org/10.5772/55316 109

The most common cause of this syndrome is a spontaneous fracture, probably due to brachial neuritis. Other causes include a space-occupying lesion, open fractures, elbow dislocation, compartment syndrome affecting the flexor compartment of the forearm, compression by the deep head of the pronator teres, the arch of flexor digitorium superficialis, or by Gantzer's

It presents principally as weakness of the index finger and thumb, and the patient may complain of diffuse pain in the proximal forearm, which may be exacerbated during exercise and diminished with rest. The vast majority of patients begin with pain in the upper arm, elbow and forearm, often preceding the motor symptoms. Pain is a common feature of anterior interosseus nerve compression, but it is not a predictive sign for differentiating an inflamma‐

During physical exam, the patient will be unable to bend the tip of the thumb and tip of index finger. The typical symptom is the inability to form an "O" with the thumb and index finger. Since flexor pollicis longus and flexor digitorium profundus to the index and middle finger are paralyzed, the patient will not be able to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Sometimes, the motor branches to pronator teres, flexor carpi radialis and/or palmaris longus are also involved. [7] Spinner [8] has described a sign in which upon making a fist, the tips of the index finger and thumb remain conspicuously excluded. The examination of the pronator quadratus is difficult and unreliable. With the elbow bent at 90º, the patient is asked to forcibly pronate the forearm against

The anterior interosseus nerve provides no sensory fibers to the skin, therefore, the sensation and sweating in the median nerve distribution is preserved. Abnormal sensibility in the median nerve distribution in the presence of an anterior interosseus syndrome, suggests a proximal median compression neuropathy involving fascicles of the anterior interosseus

Electrophysiologic tests may reveal denervation and weakness of the muscles innervated by the anterior interosseous nerve. Other studies like an MRI should be necessary in order to

discard space-occupying lesions and the involvement of bone and other structures.

*6.4.1. Innervation*

*6.4.3. Diagnosis*

*6.4.2. Causes of compression*

tory from a mechanical origin.

resistance of the examiner.

nerve. [9]

In the physical exam we may find a positive Tinel's sign at site of proximal compression within the antecubital fossa, negative over the carpal tunnel. Phalen's test will be negative. Generally, the neurophysiological exam will be normal, although in severe cases we may find fibrillations and sharp positive spikes in pronator quadratus and flexor pollicis longus.

#### *6.3.3. Treatment*

Surgical decompression is the definitive treatment. The incision should be distal to the elbow, oblique and parallel to the proximal margin of the pronator teres muscle, followed by an external neurolysis of the nerve performed proximally between the two heads of the pronator teres, and distally as it passes beneath the flexor digitorium superficialis muscle.

**Figure 3.** Carpal tunnel limits and branches of the median nerve in the hand.

#### **6.4. Anterior interosseous syndrome**

#### *6.4.1. Innervation*

*6.3.2. Diagnosis*

*6.3.3. Treatment*

There is no nocturnal preference.

The onset is insidious and is suggested when the early sensory disturbances are greater on the thumb and index finger, mainly tingling, numbness and dysaesthesia in the median nerve distribution. Patients will also complain of increased pain in the proximal forearm and greater hand numbness with sustained power gripping or rotation because these movements tighten the fibrous origin of the superficial flexor muscles beneath which the median nerve passes.

108 Peripheral Neuropathy - A New Insight into the Mechanism, Evaluation and Management of a Complex Disorder

In the physical exam we may find a positive Tinel's sign at site of proximal compression within the antecubital fossa, negative over the carpal tunnel. Phalen's test will be negative. Generally, the neurophysiological exam will be normal, although in severe cases we may find fibrillations

Surgical decompression is the definitive treatment. The incision should be distal to the elbow, oblique and parallel to the proximal margin of the pronator teres muscle, followed by an external neurolysis of the nerve performed proximally between the two heads of the pronator

and sharp positive spikes in pronator quadratus and flexor pollicis longus.

teres, and distally as it passes beneath the flexor digitorium superficialis muscle.

**Figure 3.** Carpal tunnel limits and branches of the median nerve in the hand.

The anterior interosseous nerve classically innervates these muscles: flexor pollicis longus, pronator quadratus and the radial half of flexor digitorium profundus. These muscles are in the deep level of the anterior compartment of the forearm.

#### *6.4.2. Causes of compression*

The most common cause of this syndrome is a spontaneous fracture, probably due to brachial neuritis. Other causes include a space-occupying lesion, open fractures, elbow dislocation, compartment syndrome affecting the flexor compartment of the forearm, compression by the deep head of the pronator teres, the arch of flexor digitorium superficialis, or by Gantzer's muscle (accessory head of flexor pollicis longus).

#### *6.4.3. Diagnosis*

It presents principally as weakness of the index finger and thumb, and the patient may complain of diffuse pain in the proximal forearm, which may be exacerbated during exercise and diminished with rest. The vast majority of patients begin with pain in the upper arm, elbow and forearm, often preceding the motor symptoms. Pain is a common feature of anterior interosseus nerve compression, but it is not a predictive sign for differentiating an inflamma‐ tory from a mechanical origin.

During physical exam, the patient will be unable to bend the tip of the thumb and tip of index finger. The typical symptom is the inability to form an "O" with the thumb and index finger. Since flexor pollicis longus and flexor digitorium profundus to the index and middle finger are paralyzed, the patient will not be able to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Sometimes, the motor branches to pronator teres, flexor carpi radialis and/or palmaris longus are also involved. [7] Spinner [8] has described a sign in which upon making a fist, the tips of the index finger and thumb remain conspicuously excluded. The examination of the pronator quadratus is difficult and unreliable. With the elbow bent at 90º, the patient is asked to forcibly pronate the forearm against resistance of the examiner.

The anterior interosseus nerve provides no sensory fibers to the skin, therefore, the sensation and sweating in the median nerve distribution is preserved. Abnormal sensibility in the median nerve distribution in the presence of an anterior interosseus syndrome, suggests a proximal median compression neuropathy involving fascicles of the anterior interosseus nerve. [9]

Electrophysiologic tests may reveal denervation and weakness of the muscles innervated by the anterior interosseous nerve. Other studies like an MRI should be necessary in order to discard space-occupying lesions and the involvement of bone and other structures.

#### *6.4.4. Treatment*

If the onset was spontaneous and there is no evident lesion on MRI, supportive care and corticosteroid injections with observation for 4 to 6 weeks is usually accepted management. The degree of recovery is unpredictable. If the symptoms continue we may continue with a surgical treatment where a detachment or resection of the deep head of the pronator teres muscle is performed. If there is no evident recovery, we may have to consider tendon transfers. **6.6. Anomalous interconnections**

syndrome:

hand.

*6.6.1. Diagnosis*

entity [13] (Table 1).

In some cases we may find these anomalous interconnections that may explain some clinical findings not attributable to the median nerve like little finger numbness in carpal tunnel

Compression Neuropathies http://dx.doi.org/10.5772/55316 111

**• Richie-Cannieu**: Motor and sensory interconnections from median to ulnar nerve in the

It is mainly clinic, but complementary electrophysiologic tests should be ordered. It is typically first manifested by numbness, discomfort and parestesias of the thumb, index finger, middle finger and the radial side of the ring finger. As the symptoms progress, the patient may be awakened from sleep, referring constant numbness and pain. Pain may develop on the anterior wrist or at distal forearm at the carpal tunnel entrance (Durkin sign) and may be aggravated by elevation of the hand. Skin sensibility is not disturbed in the distribution of the palmar cutaneous branch as this branch is subcutaneous and does not pass through the carpal tunnel. Phalen and Tinel tests are highly reliable for diagnosis of carpal tunnel syndrome. If both tests are positive, there is a 91% chance of an accurate diagnosis. In advanced stages of carpal tunnel

syndrome we may find thenar atrophy, which is associated with axonal damage [12].

Graham et al, developed a list of 6 clinical criteria (CTS-6) for the diagnosis of carpal tunnel syndrome, having all of them a statistically significant probability of being associated with this

Electrodiagnostic studies are reliable for evaluation of suspected carpal tunnel syndrome, but in questionable cases, clinical evaluation supersedes these studies. Abnormalities on electro‐ physiologic testing, in association with specific symptoms and signs, are considered the criterion standard for carpal tunnel syndrome diagnosis. Electrophysiologic testing also can provide an accurate assessment of how severe the damage to the nerve is, thereby directing management and providing objective criteria for the determination of prognosis. Carpal tunnel syndrome is usually divided into mild, moderate and severe. In general, patients with mild carpal tunnel syndrome have sensory abnormalities alone on electrophysiologic testing, and patients with sensory plus motor abnormalities have moderate carpal tunnel syndrome. However, any evidence of axonal loss is classified as severe carpal tunnel syndrome. [14]. Electromyography shows fibrillation and positive sharp spikes in severe compression with muscle atrophy. Nerve conduction may reveal an increase in terminal sensory latency, sensory conduction velocity or motor conduction velocity when compared with the other hand.

No imaging studies are considered routine in the diagnosis of carpal tunnel syndrome. Magnetic resonance imaging of the carpal tunnel is particularly useful preoperatively if a space-occupying lesion in the carpal tunnel is suggested. MRI does not rule out the multitude of other differential diagnoses and it is time consuming and resource intensive. [15] The same thing occurs with the use of ultrasound in the diagnosis of this entity, because there can be

**• Martin Gruber**: Motor interconnections from median to ulnar nerve in forearm.

#### **6.5. Carpal tunnel syndrome**

This is the most frequently encountered compression neuropathy in the upper limb. It is a mechanical compression of the median nerve through the fixed space of the rigid carpal tunnel. The incidence in the United States has been estimated at 1 to 3 cases per 1,000 subjects per year, with a prevalence of 50 cases per 1,000 subjects per year. [10] It is more common in women than in men (2:1), perhaps because the carpal tunnel itself may be smaller in women than in men. The dominant hand is usually affected first and produces the most severe pain. It usually occurs in adults, being the peak age range for development 45 to 60 years, and only 10% of patients are younger than 30 years. The risk of developing carpal tunnel syndrome is not confined to people in a single industry or job, but it is especially common in those performing assembly line work, manufacturing, sewing, cleaning and poultry or fish packing.

#### *6.5.1. Anatomy*

The carpal tunnel runs beneath the transverse carpal ligament, which transversely connects the pisiform, hamate, scaphoid and trapezium and longitudinally connects the deep fascia of the forearm and the palmar fascia. It contains the median nerve, 9 tendons previously described and the motor branch of the median nerve. There are three major patterns of branching of the recurrent motor branch: extraligamentous (50%), subligamentous (31%) and transligamentous (23%) [11].

#### *6.5.2. Carpal tunnel pressure*

The lowest carpal tunnel pressure at rest with wrist in neutral position is 2.5mmHg. In full wrist flexion it normally rises up to 30mmHg. In patients with carpal tunnel syndrome, this pressure rises to 30mmHg and 90mmHg respectively (Phalen's test provokes this rise in pressure).

#### *6.5.3. Etiology*

There is still some controversy among the activities that may be a direct cause of carpal tunnel syndrome. It is believed to be idiopathic in the majority of cases and it has been related to repetitive prolonged wrist extension causing mechanical irritation, synovitis and eventually compressive neuropathy of the median nerve. Trauma can be another cause of this syndrome mainly among 5% of wrist fractures and 60% of lunate dislocations. Other rare disorders include renal failure and haemodialysis, hypothyroidism, pregnancy and some spaceoccupying lesions like ganglions and nerve tumours.

#### **6.6. Anomalous interconnections**

In some cases we may find these anomalous interconnections that may explain some clinical findings not attributable to the median nerve like little finger numbness in carpal tunnel syndrome:


#### *6.6.1. Diagnosis*

*6.4.4. Treatment*

*6.5.1. Anatomy*

(23%) [11].

pressure).

*6.5.3. Etiology*

*6.5.2. Carpal tunnel pressure*

occupying lesions like ganglions and nerve tumours.

**6.5. Carpal tunnel syndrome**

If the onset was spontaneous and there is no evident lesion on MRI, supportive care and corticosteroid injections with observation for 4 to 6 weeks is usually accepted management. The degree of recovery is unpredictable. If the symptoms continue we may continue with a surgical treatment where a detachment or resection of the deep head of the pronator teres muscle is performed. If there is no evident recovery, we may have to consider tendon transfers.

110 Peripheral Neuropathy - A New Insight into the Mechanism, Evaluation and Management of a Complex Disorder

This is the most frequently encountered compression neuropathy in the upper limb. It is a mechanical compression of the median nerve through the fixed space of the rigid carpal tunnel. The incidence in the United States has been estimated at 1 to 3 cases per 1,000 subjects per year, with a prevalence of 50 cases per 1,000 subjects per year. [10] It is more common in women than in men (2:1), perhaps because the carpal tunnel itself may be smaller in women than in men. The dominant hand is usually affected first and produces the most severe pain. It usually occurs in adults, being the peak age range for development 45 to 60 years, and only 10% of patients are younger than 30 years. The risk of developing carpal tunnel syndrome is not confined to people in a single industry or job, but it is especially common in those performing

assembly line work, manufacturing, sewing, cleaning and poultry or fish packing.

The carpal tunnel runs beneath the transverse carpal ligament, which transversely connects the pisiform, hamate, scaphoid and trapezium and longitudinally connects the deep fascia of the forearm and the palmar fascia. It contains the median nerve, 9 tendons previously described and the motor branch of the median nerve. There are three major patterns of branching of the recurrent motor branch: extraligamentous (50%), subligamentous (31%) and transligamentous

The lowest carpal tunnel pressure at rest with wrist in neutral position is 2.5mmHg. In full wrist flexion it normally rises up to 30mmHg. In patients with carpal tunnel syndrome, this pressure rises to 30mmHg and 90mmHg respectively (Phalen's test provokes this rise in

There is still some controversy among the activities that may be a direct cause of carpal tunnel syndrome. It is believed to be idiopathic in the majority of cases and it has been related to repetitive prolonged wrist extension causing mechanical irritation, synovitis and eventually compressive neuropathy of the median nerve. Trauma can be another cause of this syndrome mainly among 5% of wrist fractures and 60% of lunate dislocations. Other rare disorders include renal failure and haemodialysis, hypothyroidism, pregnancy and some spaceIt is mainly clinic, but complementary electrophysiologic tests should be ordered. It is typically first manifested by numbness, discomfort and parestesias of the thumb, index finger, middle finger and the radial side of the ring finger. As the symptoms progress, the patient may be awakened from sleep, referring constant numbness and pain. Pain may develop on the anterior wrist or at distal forearm at the carpal tunnel entrance (Durkin sign) and may be aggravated by elevation of the hand. Skin sensibility is not disturbed in the distribution of the palmar cutaneous branch as this branch is subcutaneous and does not pass through the carpal tunnel. Phalen and Tinel tests are highly reliable for diagnosis of carpal tunnel syndrome. If both tests are positive, there is a 91% chance of an accurate diagnosis. In advanced stages of carpal tunnel syndrome we may find thenar atrophy, which is associated with axonal damage [12].

Graham et al, developed a list of 6 clinical criteria (CTS-6) for the diagnosis of carpal tunnel syndrome, having all of them a statistically significant probability of being associated with this entity [13] (Table 1).

Electrodiagnostic studies are reliable for evaluation of suspected carpal tunnel syndrome, but in questionable cases, clinical evaluation supersedes these studies. Abnormalities on electro‐ physiologic testing, in association with specific symptoms and signs, are considered the criterion standard for carpal tunnel syndrome diagnosis. Electrophysiologic testing also can provide an accurate assessment of how severe the damage to the nerve is, thereby directing management and providing objective criteria for the determination of prognosis. Carpal tunnel syndrome is usually divided into mild, moderate and severe. In general, patients with mild carpal tunnel syndrome have sensory abnormalities alone on electrophysiologic testing, and patients with sensory plus motor abnormalities have moderate carpal tunnel syndrome. However, any evidence of axonal loss is classified as severe carpal tunnel syndrome. [14]. Electromyography shows fibrillation and positive sharp spikes in severe compression with muscle atrophy. Nerve conduction may reveal an increase in terminal sensory latency, sensory conduction velocity or motor conduction velocity when compared with the other hand.

No imaging studies are considered routine in the diagnosis of carpal tunnel syndrome. Magnetic resonance imaging of the carpal tunnel is particularly useful preoperatively if a space-occupying lesion in the carpal tunnel is suggested. MRI does not rule out the multitude of other differential diagnoses and it is time consuming and resource intensive. [15] The same thing occurs with the use of ultrasound in the diagnosis of this entity, because there can be problems differentiating the median nerve from surrounding soft tissue, and some studies report that it does not correlate well with both clinical and electrodiagnostic criteria, limiting its role in diagnosis. [16]

*6.6.3. Complications*

**7. Ulnar nerve**

joint [23] (Figure 4).

**Figure 4.** Ulnar nerve anatomy at the elbow.

**7.1. Anatomy**

Some of the complications reported can be complex regional pain syndrome, scar pain, pillar pain, infection, injury to the palmar cutaneous branch or to the motor branch of the median nerve, vascular or tendon injury, and recurrence reported in 1% or less of the patients.

Compression Neuropathies http://dx.doi.org/10.5772/55316 113

The ulnar nerve contains fibers from C8 and T1 and is the largest terminal branch of the medial cord of the brachial plexus. The nerve enters the arm with the axillary artery and courses medially to the brachial artery before piercing the intermuscular septum approaching the elbow. It then travels along the border of the medial head of the triceps and enters the postcondylar groove lateral to the medial epicondyle [22]. At the elbow, the ulnar nerve enters the forearm between the medial epicondyle and the olecranon through the cubital tunnel. The roof of the cubital tunnel is a fibrous aponeurosis that thickens to form the cubital tunnel retinaculum or arcuate ligament of Osborne. This retinaculum connects the tendinous origin of the humeral and ulnar heads of the flexor carpi ulnaris, giving off branches to the elbow


**Table 1.** Diagnostic Clinical Criteria for Carpal Tunnel Syndrome

#### *6.6.2. Treatment*

It can be divided in non-operative and surgical decompression of the carpal tunnel. The nonoperative treatment is based in splintage of the wrist in a neutral position for three weeks and steroid injections. This therapy has variable results, with a success rate up to 76% during one year, but with a recurrence rate as high as 94%. Non-operative treatment is indicated in patients with intermittent symptoms, initial stages and during pregnancy [17].

The only definitive treatment for carpal tunnel syndrome is surgical expansion of the carpal tunnel by transection of the transverse carpal ligament. There is much controversy over what is the most appropriate surgical technique for decompression of the carpal tunnel, either by and open or by an endoscopic approach. In an attempt to resolve this issue, numerous prospective randomized trials have been reported comparing both techniques in terms of safety, efficacy, perioperative morbidity, relative costs and the return to preoperative func‐ tional status with variable results. One of the latest studies regarding this matter, was a systematic review performed in 2007 by Sholten et al, published by the Cochrane Collaboration that compared both techniques, reporting equal outcome scores by three months and with rates of complications similar in most studies, concluding there is no strong evidence to support the need for conversion from open techniques to endoscopic or more limited techni‐ ques. In addition, some other authors like Atroshi and Trumble have similar conclusions, reporting that both techniques appear to be safe and effective methods of treating carpal tunnel syndrome with no clear long-term differences in outcomes measures to support one method as clearly superior to the other. The decision as to which procedure is most appropriate, therefore, remains a matter of choice for surgeons and patients [18,19].

Other approaches like neurolysis of median nerve have been studied. Mackinnon found that it is not beneficial, with recurrence of symptoms because of internal wound healing. It would just be indicated in patients with thenar atrophy, loss of sensation or the presence of a neuroma. [20] Likewise, synovectomy is just indicated in cases of severe thenosynovytis resulting from rheumatoid arthritis, amyloidosis or renal failure. [21]

#### *6.6.3. Complications*

problems differentiating the median nerve from surrounding soft tissue, and some studies report that it does not correlate well with both clinical and electrodiagnostic criteria, limiting

112 Peripheral Neuropathy - A New Insight into the Mechanism, Evaluation and Management of a Complex Disorder

**CTS-6. Diagnostic Clinical Criteria for Carpal Tunnel Syndrome**

It can be divided in non-operative and surgical decompression of the carpal tunnel. The nonoperative treatment is based in splintage of the wrist in a neutral position for three weeks and steroid injections. This therapy has variable results, with a success rate up to 76% during one year, but with a recurrence rate as high as 94%. Non-operative treatment is indicated in patients

The only definitive treatment for carpal tunnel syndrome is surgical expansion of the carpal tunnel by transection of the transverse carpal ligament. There is much controversy over what is the most appropriate surgical technique for decompression of the carpal tunnel, either by and open or by an endoscopic approach. In an attempt to resolve this issue, numerous prospective randomized trials have been reported comparing both techniques in terms of safety, efficacy, perioperative morbidity, relative costs and the return to preoperative func‐ tional status with variable results. One of the latest studies regarding this matter, was a systematic review performed in 2007 by Sholten et al, published by the Cochrane Collaboration that compared both techniques, reporting equal outcome scores by three months and with rates of complications similar in most studies, concluding there is no strong evidence to support the need for conversion from open techniques to endoscopic or more limited techni‐ ques. In addition, some other authors like Atroshi and Trumble have similar conclusions, reporting that both techniques appear to be safe and effective methods of treating carpal tunnel syndrome with no clear long-term differences in outcomes measures to support one method as clearly superior to the other. The decision as to which procedure is most appropriate,

Other approaches like neurolysis of median nerve have been studied. Mackinnon found that it is not beneficial, with recurrence of symptoms because of internal wound healing. It would just be indicated in patients with thenar atrophy, loss of sensation or the presence of a neuroma. [20] Likewise, synovectomy is just indicated in cases of severe thenosynovytis resulting from

with intermittent symptoms, initial stages and during pregnancy [17].

therefore, remains a matter of choice for surgeons and patients [18,19].

rheumatoid arthritis, amyloidosis or renal failure. [21]

its role in diagnosis. [16]

2: Nocturnal numbness

6: Loss of 2-point discrimination

4: Tinel's sign 5: Phalen's test

*6.6.2. Treatment*

1: Numbness and tingling in the median nerve distribution

**Table 1.** Diagnostic Clinical Criteria for Carpal Tunnel Syndrome

3: Weakness and/or atrophy of the thenar musculature

Some of the complications reported can be complex regional pain syndrome, scar pain, pillar pain, infection, injury to the palmar cutaneous branch or to the motor branch of the median nerve, vascular or tendon injury, and recurrence reported in 1% or less of the patients.
