Entrapment neuropathies of the upper extremity - 수근관증후군에 관한 모든 것

[문형철]

상지 신경의 포착증후군의 진단과 치료에 관하여

- 정중신경포착증후군 carpal tunnel syndrome

드디어 찾았다. 신경스트레칭의 횟수와 시간을 언급한 자료

The author of this paper utilizes a technique that includes 3 sets of 10 repetitions in each set, at a moderate pace and a 3 second hold at the final stretched position.

Entrapment neuropathies of the upper extremity.pdf

Anatomic Variations of the Median Nerve in the carpal tunne.pdf

Treatment of carpal tunnel syndrome.pdf

Abstract

Painful tingling, numbness, weakness of the hands or upper extremities may be the result of the entrapment of a peripheral nerve. Although these problems are common, they sometimes lead to diagnostic and management difficulties. A thorough knowledge of the anatomy of the common entrapment sites, the pathophysiology of the nerve injury, a detailed history and physical examination together with electrodiagnostic studies usually lead physicians to the right management. Most common upper extremity entrapment neuropathies are encountered in this review.

- 통증성 찌릿찌릿함, 저림, 손 또는 상지의 근력약화는 정중신경 포착의 결과일 수 있음. 

- 수근관 증후군은 매우 흔하지만, 때로 진단과 치료가 어려움. 

- 정중신경이 포착되는 해부학적 위치이해를 통해, 신경손상의 병리, 자세한 병력청취, 이학적 검사, EMG검사 등을 정확히 하고 치료에 응용할 수 있음. 

Introduction

Entrapment or compressive neuropathies are important and widespread debilitating clinical problems, especially in patients with predisposing occupations or with certain medical disorders. They are caused by mechanical dynamic compression of a short segment of a single nerve at a specific site, frequently as it passes through a fibro-osseous tunnel, or an opening in fibrous or muscular tissue. 

By far the most common is median nerve entrapment in the wrist leading to so-called carpal tunnel syndrome (CTS). CTS is one of the most common orthopedic conditions, with an estimated incidence of nearly 1% annually in the USA, which makes almost 2.8 million new cases per year [1] and the surgery performed for CTS accounts for the most common operation performed on the hand [2, 3]. Its overall incidence varies between 0.125% and 5.8% of the population, depending on the criteria used for population surveying [4–9]. 

In the upper limbs, ulnar nerve and posterior interosseous branch of the radial nerve can also be entrapped leading to cubital tunnel syndrome (CuTS) and radial tunnel syndrome (RTS) respectively. Other entrapment neuropathies have been recognized in the upper extremity, involving the superficial sensory radial nerve, the anterior interosseous nerve, the median nerve in the elbow region (e.g. pronator syndrome), the ulnar nerve at the base of the palm (Guyon’s canal), the palmar cutaneous branch of the median nerve, and various components of the brachial plexus (neurogenic thoracic outlet syndrome). 

Anatomical variations, a hypertrophied subscapularis muscle may lead to entrapment of the suprascapular nerve [10, 11]. Detailed anatomical studies have been performed to clarify the basic mechanical aspects of these syndromes. Yet, there is still discussion regarding the best methods for eval‎uating patients both initially and in follow-up, and the most appropriate treatment. 

New radiographic and electromyographic methods may allow rapid and accurate assessment of the location and severity of nerve compression. 

This review focuses on most common upper extremity entrapment neuropathies which are the CTS, CuTS, RTS and neurogenic thoracic outlet syndrome. Anatomical considerations, patient eval‎uation, indications for conservative treatment and surgical intervention, outcomes, and complications are discussed.

1. Carpal Tunnel Syndrome

Anatomy and Pathophysiology

The carpal bones and intercarpal ligaments at its medial, lateral and posterior borders form the carpal tunnel. The anterior border is formed by the transverse carpal ligament and flexor retinaculum [12, 13]. The flexor retinaculum (FR) as a whole can be divided into three parts from proximal to distal. The antebrachial fascia forms the proximal part of the FR. A superficial fascial layer is inseparable from the thickened deep investing antebrachial fascia, which is anterior to the median nerve and continuous with the transverse carpal ligament distally. The two layers separate to enclose the flexor carpi radialis tendon radially and the contents of Guyon’s canal and flexor carpi ulnaris tendon ulnarly. Thus, the deep investing antebrachial fascia at this level is volar to the contents of the carpal tunnel and dorsal to Guyon’s canal [14]. 

다른 논문자료

Treatment of carpal tunnel syndrome.pdf

The transverse carpal ligament proper represents the middle third of the FR and forms the palmar ‘roof’ of the carpal tunnel. It inserts into the scaphoid tuberosity and ridge of the trapezium radially and the hamulus and pisiform ulnarly where it is narrowest between the hamate hook and trapezial ridge.

The distal third is the aponeurosis between the thenar and hypothenar muscles, from which these muscles originate. The thickness of the FR over the carpal tunnel is 10 times that of the antebrachial fascia [14]. A cross-section at the wrist reveals a tunnel tightly packed with the median nerve and the nine extrinsic flexor tendons of the thumb and fingers (flexor pollicis longus tendon, four flexor digitorum superficialis tendons and four flexor digitorum profundus tendons) and synovium.

The median nerve normally divides into six branches at the distal end of the FR. The six branches include the recurrent motor branch encompassing: a proper digital nerve to radial side of the thumb; a short common digital nerve to the first web space that quickly divides into a proper digital nerve to the ulnar side of the thumb and a proper digital nerve to the radial side of the index finger; and two common digital nerves to the second and third web spaces.

Lanz defined four categories of variations found in this nerve in the carpal tunnel: 1) variations in the course of

the thenar branch; 2) accessory branches at the distal carpal tunnel; 3) high division of the distal median nerve; and 4) accessory branches proximal to the carpal tunnel. 

Furthermore, the motor branch may arise in the forearm, or may be separated by the persistent median artery or an aberrant muscle only to join distal to the transverse carpal ligament [15]. Studies of carpal tunnel dimensions using computed tomography or magnetic resonance imaging have yielded some consistent and some inconsistent anatomical

findings [16–18]. In one of them, post-operative tunnel volume was found to be increased by 24.2% at 6 weeks and this increase in volume was also found at 8 months follow-up. 

Tunnel contents were displaced anteriorly after decompression at both 6 weeks and 8 months, but the carpal arch width was not changed [17]. In the other three studies, however, carpal arch width increased by between 7% and 11% after surgery [16, 18].

It has been hypothesized that median nerve compression most likely occurs in wrist flexion at the proximal edge of the transverse carpal ligament where it joins the deep investing fascia of the forearm, the anatomic explanation for Phalen’s sign. Alternately, the median nerve may be compressed where the carpal tunnel is narrowest at the level of the hook of the hamate by either synovial hypertrophy or a space-occupying lesion [14]. 

Using dynamic imaging techniques, several investigators have shown changes in position of carpal contents [17–18], and changes in pressure within the canal [21–24]. Imaging studies of median nerve during wrist flexion have demonstrated that patients with carpal tunnel syndrome are more likely than normal patients to have limited median nerve motion in the carpal canal. The nerve in normal patients moved radially and posteriorly to a position interposed between the flexor

tendons during wrist flexion. The nerve in patients with carpal tunnel syndrome was more likely to remain in position at the FR. 

The limited motion of the nerve in these cases may predispose the nerve to compression during wrist flexion leading to carpal tunnel symptoms [25]. It was reported by Szabo and Chidgey that tunnel pressure after repeated flexion/extension movements took significantly longer to recover in patients with CTS than in normal subjects [24]. Decreased median nerve motion during flexion was observed in patients with nonspecific forearm pain with median nerve compression in another study [26]. 

The sliding of median nerve in response to not only wrist, but also elbow, shoulder and neck movements was analyzed in a study by Dilley et al. [27] and the median nerve was found to be unloaded  when the shoulder was adducted or elbow flexed. It was reported in the same study that even when the nerve was loaded in the shoulder abducted, elbow straight and wrist in 60º extension, the blood flow to or conduction in the median nerve was unaffected. It was concluded that the median nerve was well designed to cope with changes in bed length caused by limb movements [27].

다른논문자료

The three leading theories of causation of CTS are: 

1) repeated compression leading to ischemia, edema formation in the subendoneurial space and the synovium and eventually fibrosis [28], 

2) tethering of the nerve due to scar tissue leading to reduced nerve gliding and ischemia [29–31], and 

3) localized mechanical pressure from structures such as the FR causing local nerve damage [32]. These theories may overlap, e.g., an increase in extraneurial pressure may push the nerve against a stiff tissue and lead to a localized injury due to mechanical pressure.

Anatomic variations

Various congenital variations intrinsic to the carpal tunnel, anomalous lumbrical origins, presence of a flexor digitorum superficialis muscle belly [33, 34], bifid median nerves, either at the forearm or wrist level [35–38] have been reported. It should be kept in mind that anomalous muscles are occasionally found in this region and can lead to CTS [39, 40]. A patient having both carpal and ulnar tunnel symptoms was reported to have a muscle originating at the tendon of the palmaris longus and ulnar antebrachial fascia that split and extended through Guyon’s canal to join portions of the

abductor digiti minimi and the FR [40]. Transfer of sensory information between ulnar and median nerves is described [41]. A communicating branch conveying sensory information from the little finger passing from median to ulnar just proximal to the wrist was reported by Saeed and Davies [42]. It was not until this anomalous symptoms were relieved although open release of the carpal tunnel was performed 7 years before.

Patient Eval‎uation

Clinical assessment includes Phalen’s test (appearance or worsening of paresthesia with maximal passive wrist

flexion for one minute) and Tinel’s sign (paresthesia in the median territory elicited by gentle tapping over the carpal tunnel). Tinel’s sign has a sensitivity of 60% and a specificity of 67%; the corresponding values for Phalen’s test are 75% and 47% [43, 44]. When conducted in the proper setting, these tests can provide useful information. In a clinical setting, an assessment of strength, sensory loss, and pain is sufficient to monitor the progress of the syndrome. 

Electrodiagnostic testing should be carried out in most cases. Sensory fibers are used to measure the nerve

conduction velocity from the finger or palm to the wrist and motor conduction velocity from the wrist to the thenar muscles. 

The palmar serial sensory study – sequential measurements at short distances over the course of the nerve in the palm – improves the sensitivity of sensory conduction testing [45]. Electromyography of thenar muscles innervated by the median nerve is also usually done. Eval‎uation of selected patients with imaging in addition to nerve conduction studies may be important, as a proportion of symptomatic patients fail to show a decreased median nerve conduction velocity [19, 46].

Mesgarzadeh et al. noted four general findings by MRI in CTS regardless of the etiology, including swelling of the median nerve (best eval‎uated at the pisiform level), flattening of the nerve at the hamate level, palmar bowing of the FR, and increased T2 signal in the median nerve [47]. MRI was also shown to be able to discern unexpected causes of typical CTS prior to surgery, such as a large adductor pollicis muscle, a persistent median artery, an excessive amount of fat tissue within the tunnel, a ganglion cyst, and synovial hypertrophy related to rheumatoid arthritis.

다른 자료 참조) 

MR Imaging of wrist, hand.pdf

Other methods of imaging the region of the carpal tunnel, like ultrasound and thermography have been eval‎uated

[48–50]. The high spatial resolution and exquisite flow detection methods of ultrasound allows analysis of many superficial soft tissue structures. Abnormalities such as tenosynovitis, synovial hypertrophy, ganglia, giant cell tumor of the tendon sheath, lipomas, aberrant musculovascular anatomy and bursae, metabolic edema and infiltrative processes (e.g. amyloidosis) have all been identified as causes of carpal and tarsal tunnel syndromes [51–53]. Thermography shows clear abnormalities in CTS, but is not reliable for the diagnosis of bilateral cases and has limited value in the differential diagnosis [50].

The standard means of diagnosis is accepted to be the electrodiagnostic testing together with clinical eval‎uation [54]. Most electromyographers consider the following results abnormal (with control for the patient’s age and limb temperature): an absolute sensory latency of more than 3.7 msec, a difference of 0.4 msec or more between values obtained for the median nerve and those obtained for the radial or ulnar nerve, a motor conduction latency of more than 4.0 msec, and an incremental change of 0.4 msec in the palmar serial sensory study with the use of measurements made at standard distances [55]. Eval‎uation of F-wave responses [56, 57], or combined indices of median versus ulnar nerve conduction data [58, 59], could be used for better diagnosing the possibility of the so called ‘double crush’ phenomenon [60], and in demonstrating higher sensitivity and specificity in routine CTS diagnosis [58, 59].

Treatment

Conservative treatment includes the avoidance of the use of wrist, using a wrist splint in a neutral position for day and night time, anti-inflammatory medication. Patients with minimal or intermittent symptoms usually get benefit from this kind of nonsurgical management. According to the Practice Parameter of the American Academy of Neurology, local steroid injections are considered a treatment for mild CTS [61]. Several investigators have reported that local steroid injection

into the carpal tunnel is an effective treatment of CTS [62–65]. Improvements of nerve conduction parameters beginning as early as 1 month and lasting for at least 6 months by local steroid injections were reported by Hagebeuk and de Weerd [66]. 

Subjective measures were also improved in this study, although these measures were not correlated with the improvements in nerve conduction parameters. Surgical intervention is recommended for patients with CTS if they have failed conservative management, or if they have intolerable pain, constant numbness, or any weakness limiting their activities. The procedure is usually done on an outpatient basis and has a good record of success. The surgical technique is either standard open release or endoscopic release. The complication and success rates are similar, but patients return to work sooner and with less pain and debilitation after endoscopic procedures [67].

Complications of carpal tunnel release can be generally reported as incomplete release, neuropraxia or injury

to the median or ulnar nerve, inadvertent entrance into Guyon’s canal, injury to the digital nerves, the ulnar artery and the superficial palmar arch [68, 69].

Abstract 

Carpal tunnel syndrome (CTS) results from the entrapment of the median nerve at the wrist. It is the most common entrapment syndrome causing frequent disability especially to working populations. Aside from the surgical release approach there are other non-invasive therapeutic methods for the treatment of CTS. This paper will review the evidence regarding neurodynamic testing and neuromobilization of the median nerve as a treatment approach to CTS.

The author of this paper utilizes a technique that includes 3 sets of 10 repetitions in each set, at a moderate pace and a 3 second hold at the final stretched position.

ABSTRACT

Carpal tunnel syndrome (CTS) is a common focal peripheral neuropathy. Increased pressure in the carpal tunnel results in median nerve compression and impaired nerve perfusion, leading to discomfort and paresthesia in the affected hand. Surgical division of the transverse carpal ligament is preferred in severe cases of CTS and should be considered when conservative measures fail. A through knowledge of the normal and variant anatomy of the median nerve in the wrist is fundamental in avoiding complications during carpal tunnel release. This paper aims to briefly review the anatomic variations of the median nerve in the carpal tunnel and its implications in carpal tunnel surgery.

Figure 3: Lanz classification of the median nerve anatomical variations at the wrist. Group I, Thenar branch variations; 1A:

subligamentous; 1B: transligamentous; 1C: ulnarwards; 1D: supraligamentous. Group 0, extraligamentous thenar branch. Group II, distal accessory thenar branch. Group IV, proximal accessory thenar branch; 4A: running directly in the thenar muscles; 4B: joining another branch. Group III, high division of the median nerve; 3A: without an artery of muscle; 3B: with artery; 3C: with lumbrical muscle.

[송영석]

혼자서 할 수 있는 방안을 생각하면 김송준소장님 스트레칭 방법중에 비슷한 게 있네요 ㅎㅎㅎ