Anterior interosseous syndrome

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Anterior interosseous syndrome
Other namesKiloh-Nevin syndrome I
Specialty Neurology, hand surgery   OOjs UI icon edit-ltr-progressive.svg

Anterior interosseous syndrome is a medical condition in which damage to the anterior interosseous nerve (AIN), a distal motor and sensory branch of the median nerve, classically with severe weakness of the pincer movement of the thumb and index finger, and can cause transient pain in the wrist (the terminal, sensory branch of the AIN innervates the bones of the carpal tunnel).

Contents

Most cases of AIN syndrome are now thought to be due to a transient neuritis, although compression of the AIN in the forearm is a risk, such as pressure on the forearm from immobilization after shoulder surgery. Trauma to the median nerve or around the proximal median nerve have also been reported as causes of AIN syndrome.

Although there is still controversy among upper extremity surgeons, AIN syndrome is now regarded as a neuritis (inflammation of the nerve) in most cases; this is similar to Parsonage–Turner syndrome. Although the exact etiology is unknown, there is evidence that it is caused by an immune-mediated response that can follow other illnesses, such as pneumonia or severe viral illness.[ citation needed ]

Studies are limited, and no randomized controlled trials have been performed regarding the treatment of AIN syndrome. While the natural history of AIN syndrome is not fully understood, studies following patients who have been treated without surgery show that symptoms can resolve starting as late as one year after onset. Other retrospective studies have concluded that there is no difference in outcome in surgically versus nonsurgically treated patients. The role of surgery in AIN syndrome remains controversial. Indications for considering surgery include a known space-occupying lesion that is compressing the nerve (a mass) or fascial compression, and persistent symptoms beyond 1 year of conservative treatment.

Symptoms and signs

The findings are weakness in bending (flexion) the tips of the thumb and index finger. [1]

Clinical signs

In a pure lesion of the anterior interosseous nerve there is weakness of the long flexor muscle of the thumb (Flexor pollicis longus), the deep flexor muscles of the index and middle fingers (Flexor digitorum profundus I & II).

Causes

Injuries of the forearm with compression of the nerve from swelling is the most common cause: examples include supracondylar fractures, often associated with haemorrhage into the deep musculature; injury secondary to open reduction of a forearm fracture; or dislocation of the elbow.⁠⁠ [2] [3]

Direct trauma from a penetrating injury such as a stab wound is a possible cause for the syndrome.[ citation needed ]

Fibrous bands or Arcuate ligament~arcuate (curved) ligaments may entrap the median as well as the anterior interosseous nerve, in which case a patient may experience hand numbness as well as wrist pain.⁠⁠ [4] [5]

Very similar syndromes can be caused by more proximal lesions, such as brachial plexus neuritis.⁠ [6]

Anterior interosseous nerve entrapment or compression injury remains a difficult clinical diagnosis because it is mainly a motor nerve problem, and the syndrome is often mistaken for index finger and/or thumb tendon injury.⁠ [7]

Although there is still controversy among upper extremity surgeons, AIN syndrome is now regarded as a neuritis (inflammation of the nerve) in most cases; this is similar to Parsonage–Turner syndrome. Although the exact etiology is unknown, there is evidence that it is caused by an immune-mediated response that can follow other illnesses, such as pneumonia or severe viral illness.[ citation needed ]

Anatomy

The anterior interosseous nerve is a branch of the median nerve, with a large sensory branch to the wrist bones, which arises just below the elbow. It passes distally, anteriorly along the interosseous membrane and innervates flexor pollicis longus, flexor digitorum profundus to index and middle finger as well as pronator quadratus, and supplies sensory feedback from the wrist bones, i.e. the carpal tunnel, not skin.[ citation needed ]

Diagnosis

Electrophysiologic testing is an essential part of the evaluation of anterior interosseous nerve syndrome. Nerve conduction studies may be normal or show pronator quadratus latency.⁠⁠ [7] Electromyography (EMG) is generally most useful and will reveal abnormalities in the flexor pollicis longus, flexor digitorum profundus I and II and pronator quadratus muscles.⁠⁠ [8] [7]

The role or MRI and ultrasound imaging in the diagnosis of Kiloh-Nevin syndrome is unclear.⁠ [9] [10]

If asked to make the "OK" sign, patients will make a triangle sign instead. This 'pinch-test' exposes the weakness of the flexor pollicis longus muscle and the flexor digitorum profundus I leading to weakness of the flexion of the distal phalanges of the thumb and index finger. This results in impairment of the pincer movement and the patient will have difficulty picking up a small item, such as a coin, from a flat surface. [3] [11]

Ericson's Test

Ericson's Test [12] [13] is a clinical maneuver for assessing the strength of the FDP and FPL muscles in anterior interosseous nerve syndrome, and other proximal entrapments of the median nerve.

In contrast to the "OK sign," Ericson's test isolates the action of the FDP and FPL while eliminating the contribution of the tenodesis effect and other adaptations that patients may use, usually unconsciously, to augment distal pincer strength. Failing to control for compensatory wrist tenodesis can mask an underlying proximal median nerve weakness in a patient who can otherwise make a normal OK-sign.[ citation needed ]

While facing the patient in what resembles an arm wrestling stance, with elbows planted firmly on a level surface and maintained touching the thorax, the examiner uses one hand to lock the patient's wrist in neutral, around which the patient curls his fingers. With the other hand, the examiner then attempts to "peel" back the tips of each individual finger against patient resistance. It is crucial that motion of the upper extremity be restricted to the distal IP joint, and that the MP and PIP joints are in full flexion and wrist neutral or slightly flexed. If the distal flexors of the index finger and thumb are weak, the patient will be unable to resist this motion, and Ericson's test is considered positive for proximal median nerve weakness. [14]

Ericson's test is frequently positive for proximal median nerve weakness (of which AIN syndrome is but one subtype) even in the context of normal imaging, EMG, and nerve conduction studies, which highlights the clinical nature of the diagnosis. Overreliance on electrical diagnostic workup unfairly excludes patients who would otherwise benefit from surgical decompression.[ citation needed ]

Treatment

Surgical decompression can give excellent results if the clinical picture and the EMG suggest a compression neuropathy. [15] [16] [17] In brachial plexus neuritis, conservative management may be more appropriate. [6] Spontaneous recovery has been reported, but is said to be delayed and incomplete. [3] [18]

There may be a role for physiotherapy in some cases, and this should be directed specifically towards the pattern of pain and symptoms. Soft tissue massage, stretches and exercises to directly mobilise the nerve tissue may be used.⁠ [19]

History

The syndrome was first described by Parsonage and Turner in 1948⁠ [20] and further defined as isolated lesion of the anterior interosseous nerve by Leslie Gordon Kiloh and Samuel Nevin in 1952. [21]

Related Research Articles

<span class="mw-page-title-main">Carpal bones</span> Eight small bones that make up the wrist (or carpus) that connects the hand to the forearm

The carpal bones are the eight small bones that make up the wrist (carpus) that connects the hand to the forearm. The term "carpus" and "carpal" is derived from the Latin carpus and the Greek καρπός (karpós), meaning "wrist". In human anatomy, the main role of the carpal bones is to articulate with the radial and ulnar heads to form a highly mobile condyloid joint, to provide attachments for thenar and hypothenar muscles, and to form part of the rigid carpal tunnel which allows the median nerve and tendons of the anterior forearm muscles to be transmitted to the hand and fingers.

<span class="mw-page-title-main">Median nerve</span> Nerve of the upper limb

The median nerve is a nerve in humans and other animals in the upper limb. It is one of the five main nerves originating from the brachial plexus.

<span class="mw-page-title-main">Wrist</span> Part of the arm between the lower arm and the hand

In human anatomy, the wrist is variously defined as (1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand; (2) the wrist joint or radiocarpal joint, the joint between the radius and the carpus and; (3) the anatomical region surrounding the carpus including the distal parts of the bones of the forearm and the proximal parts of the metacarpus or five metacarpal bones and the series of joints between these bones, thus referred to as wrist joints. This region also includes the carpal tunnel, the anatomical snuff box, bracelet lines, the flexor retinaculum, and the extensor retinaculum.

The flexor digitorum profundus is a muscle in the forearm of humans that flexes the fingers. It is considered an extrinsic hand muscle because it acts on the hand while its muscle belly is located in the forearm.

<span class="mw-page-title-main">Ulnar nerve</span> Nerve which runs near the ulna bone

The ulnar nerve is a nerve that runs near the ulna, one of the two long bones in the forearm. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of these fingers, including both front and back of the tips, perhaps as far back as the fingernail beds.

<span class="mw-page-title-main">Wrist drop</span> Medical condition

Wrist drop is a medical condition in which the wrist and the fingers cannot extend at the metacarpophalangeal joints. The wrist remains partially flexed due to an opposing action of flexor muscles of the forearm. As a result, the extensor muscles in the posterior compartment remain paralyzed.

<span class="mw-page-title-main">Radius (bone)</span> One of the two long bones of the forearm

The radius or radial bone is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer than the radius, but the radius is thicker. The radius is a long bone, prism-shaped and slightly curved longitudinally.

<span class="mw-page-title-main">Upper limb</span> Consists of the arm, forearm, and hand

The upper limbs or upper extremities are the forelimbs of an upright-postured tetrapod vertebrate, extending from the scapulae and clavicles down to and including the digits, including all the musculatures and ligaments involved with the shoulder, elbow, wrist and knuckle joints. In humans, each upper limb is divided into the arm, forearm and hand, and is primarily used for climbing, lifting and manipulating objects.

<span class="mw-page-title-main">Phalen maneuver</span> Diagnostic test for carpal tunnel syndrome

Phalen's maneuver is a diagnostic test for carpal tunnel syndrome by an American orthopedist named George S. Phalen.

The flexor pollicis longus is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus. This muscle is unique to humans, being either rudimentary or absent in other primates. A meta-analysis indicated accessory flexor pollicis longus is present in around 48% of the population.

<span class="mw-page-title-main">Galeazzi fracture</span> Medical condition

The Galeazzi fracture is a fracture of the distal third of the radius with dislocation of the distal radioulnar joint. It classically involves an isolated fracture of the junction of the distal third and middle third of the radius with associated subluxation or dislocation of the distal radio-ulnar joint; the injury disrupts the forearm axis joint.

<span class="mw-page-title-main">Anterior interosseous artery</span>

The anterior interosseous artery is an artery in the forearm. It is a branch of the common interosseous artery.

<span class="mw-page-title-main">Anterior interosseous nerve</span>

The anterior interosseous nerve is a branch of the median nerve that supplies the deep muscles on the anterior of the forearm, except the ulnar (medial) half of the flexor digitorum profundus. Its nerve roots come from C8 and T1.

<span class="mw-page-title-main">Carpal tunnel</span> Structure of human wrist

In the human body, the carpal tunnel or carpal canal is a flattened body cavity on the flexor (palmar/volar) side of the wrist, bounded by the carpal bones and flexor retinaculum. It forms the passageway that transmits the median nerve and the tendons of the extrinsic flexor muscles of the hand from the forearm to the hand. The median artery is an anatomical variant. When present it lies between the radial artery, and the ulnar artery and runs with the median nerve supplying the same structures innervated.

<span class="mw-page-title-main">Ulnar neuropathy at the elbow</span> Medical condition

Idiopathic ulnar neuropathy at the elbow is a condition where pressure on the ulnar nerve as it passes through the cubital tunnel causes ulnar neuropathy. The symptoms of neuropathy are paresthesia (tingling) and numbness primarily affecting the little finger and ring finger of the hand. Ulnar neuropathy can progress to weakness and atrophy of the muscles in the hand. Symptoms can be alleviated by the use of a splint to prevent the elbow from flexing while sleeping.

<span class="mw-page-title-main">Cervical spinal nerve 8</span> Spinal nerve of the cervical segment

The cervical spinal nerve 8 (C8) is a spinal nerve of the cervical segment.

<span class="mw-page-title-main">Ulnar claw</span> Deformity of the hand that develops due to ulnar nerve damage

An ulnar claw, also known as claw hand or ‘Spinster’s Claw’, is a deformity or an abnormal attitude of the hand that develops due to ulnar nerve damage causing paralysis of the lumbricals. A claw hand presents with a hyperextension at the metacarpophalangeal joints and flexion at the proximal and distal interphalangeal joints of the 4th and 5th fingers. The patients with this condition can make a full fist but when they extend their fingers, the hand posture is referred to as claw hand. The ring- and little finger can usually not fully extend at the proximal interphalangeal joint (PIP).

<span class="mw-page-title-main">Pronator teres syndrome</span> Medical condition

Pronator teres syndrome is a compression neuropathy of the median nerve at the elbow. It is rare compared to compression at the wrist or isolated injury of the anterior interosseous branch of the median nerve.

<span class="mw-page-title-main">Median nerve palsy</span> Medical condition

Injuries to the arm, forearm or wrist area can lead to various nerve disorders. One such disorder is median nerve palsy. The median nerve controls the majority of the muscles in the forearm. It controls abduction of the thumb, flexion of hand at wrist, flexion of digital phalanx of the fingers, is the sensory nerve for the first three fingers, etc. Because of this major role of the median nerve, it is also called the eye of the hand. If the median nerve is damaged, the ability to abduct and oppose the thumb may be lost due to paralysis of the thenar muscles. Various other symptoms can occur which may be repaired through surgery and tendon transfers. Tendon transfers have been very successful in restoring motor function and improving functional outcomes in patients with median nerve palsy.

<span class="mw-page-title-main">Palmaris profundus muscle</span>

Palmaris profundus is a rare anatomical variant in the anterior compartment of forearm. It was first described in 1908. It is usually found incidentally in cadaveric dissection or surgery.

References

  1. ↑ Sood, M. K.; Burke, F. D. (1997). "Anterior interosseous nerve palsy. A review of 16 cases". The Journal of Hand Surgery. 22 (1): 64–68. doi:10.1016/s0266-7681(97)80020-4. PMID   9061529.
  2. ↑ Penkert, G, and D Schwandt. "[A case of anterior interosseus nerve lesion (Kiloh-Nevin syndrome)]." Handchirurgie 12, no. 1-2 (1980): 19-21. PMID   7250795.
  3. 1 2 3 Van Der Wurff, P, R H Hagmeyer, and W Rijnders. "Case Study: Isolated Anterior Interosseous Nerve Paralysis: The - Kiloh-Nevin Syndrome." The Journal of Orthopaedic and Sports Physical Therapy 6, no. 3 (1984): 178-80. PMID   2065.
  4. ↑ Rask, M R. "Anterior interosseous nerve entrapment: (Kiloh-Nevin syndrome) report of seven cases." Clinical Orthopaedics and Related Research, no. 142: 176-81. PMID   498633.
  5. ↑ Knight, C R, and P Kozub. "Anterior interosseous syndrome." Annals of Plastic Surgery 3, no. 1 (July 1979): 72-6. PMID   543635.
  6. 1 2 Schollen, Wilfried, Ilse Degreef, and Luc De Smet. "Kiloh-Nevin syndrome: a compression neuropathy or brachial plexus neuritis?." Acta Orthopaedica Belgica 73, no. 3 (June 2007): 315-8. PMID   17715720.
  7. 1 2 3 Rosenberg, J N. "Anterior interosseous/median nerve latency ratio." Archives of Physical Medicine and Rehabilitation 71, no. 3 (March 1990): 228-30. PMID   2317141.
  8. ↑ Gessini, L, L Bove, B Jandolo, C Landucci, and A Pietrangeli. "[Anterior interosseus nerve syndrome (Kiloh-Nevin) (author's transl)]." Rivista Di Patologia Nervosa E Mentale 101, no. 1: 1-11. PMID   7244544.
  9. ↑ Roggenland, D, C M Heyer, M Vorgerd, and V Nicolas. "[Nervus interosseus anterior syndrome (Kiloh-Nevin syndrome)--diagnosis with MRI]." RöFo: Fortschritte Auf Dem Gebiete Der Röntgenstrahlen Und Der Nuklearmedizin 180, no. 6 (June 2008): 561-2. PMID   18584776.
  10. ↑ Martinoli, Carlo, Stefano Bianchi, Francesca Pugliese, Lorenzo Bacigalupo, Cristina Gauglio, Maura Valle, et al. "Sonography of entrapment neuropathies in the upper limb (wrist excluded)." Journal of Clinical Ultrasound: JCU 32, no. 9: 438-50. doi : 10.1002/jcu.20067.
  11. ↑ Spinner, M. "The functional attitude of the hand afflicted with an anterior interosseous nerve paralysis." Bulletin of the Hospital for Joint Diseases 30, no. 1 (April 1969): 21-2. PMID   5348010.
  12. ↑ "Median Nerve Entrapments," Ericson WB, Singh V, in "Peripheral Nerve Entrapments: Clinical Diagnosis and Management," Trescot AM, Editor. Springer, April 2016, p369-382
  13. ↑ "Management of Compressive Neuropathies of the Upper Extremity," Kalliainen LK, Ericson WB, in "Grabb and Smith's Plastic Surgery, 8th Edition", Chung K et al editors, Lippincott Williams & Wilkins, 2018. Chapter 70.
  14. ↑ "Dual Oblique Skin Incisions For Proximal Median Entrapment" W.B. Ericson
  15. ↑ Stern, M B. "The anterior interosseous nerve syndrome (the Kiloh-Nevin syndrome). Report and follow-up study of three cases." Clinical Orthopaedics and Related Research, no. 187: 223-7. PMID   6744722.
  16. ↑ Nigst, H, and W Dick. "Syndromes of compression of the median nerve in the proximal forearm (pronator teres syndrome; anterior interosseous nerve syndrome)." Archives of Orthopaedic and Traumatic Surgery. Archiv für Orthopädische und Unfall-Chirurgie 93, no. 4 (April 30, 1979): 307-12. PMID   464765.
  17. ↑ Souquet, R, M Mansat, and J P Chavoin. "[Median nerve compression syndrome at the elbow (author's transl)]." La Semaine Des Hôpitaux: Organe Fondé Par l'Association D'enseignement Médical Des Hôpitaux De Paris 58, no. 17 (April 29, 1982): 1060-4. PMID   6285484.
  18. ↑ Crawford, J P, and W J Noble. "Anterior interosseous nerve paralysis: cubital tunnel (Kiloh-Nevin) syndrome." Journal of Manipulative and Physiological Therapeutics 11, no. 3 (June 1988): 218-20. PMID   3392477.
  19. ↑ Internullo, G, A Marcuzzi, R Busa, C Cordella, and A Caroli. "Kiloh-Nevin syndrome: a clinical case of compression of the anterior interosseous nerve." La Chirurgia Degli Organi Di Movimento 80, no. 3: 345-8. PMID   8681687.
  20. ↑ PARSONAGE, M J, and J W A TURNER. "Neuralgic amyotrophy; the shoulder-girdle syndrome." Lancet 1, no. 26 (June 26, 1948): 973-8. PMID   18866299.
  21. ↑ KILOH, L G, and S NEVIN. "Isolated neuritis of the anterior interosseous nerve." British Medical Journal 1, no. 4763 (April 19, 1952): 850-1. PMC   2023229.
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