The radial nerve provides motor innervation and sensory innervation to parts of the arm and forearm. Radial nerve injuries can occur due to fractures, lacerations, or compression neuropathies. Treatment depends on the level and severity of injury, and may involve nerve repair/grafting, tendon transfers, or splinting. Common tendon transfers include the palmaris longus to extensor pollicis longus, flexor carpi ulnaris to extensor digitorum communis, and pronator teres to extensor carpi radialis brevis. Postoperative splinting and rehabilitation are important after surgical treatment of radial nerve injuries.
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Radial nerve anatomy and injuries
1. RADIAL NERVE
INJURIES
Dr Siddharth S P
JR3, Department of Orthopaedics
SMS Medical College, Jaipur
Under guidance of Dr Narender Saini sir
2. ANATOMY
• Radial nerve (C5, 6, 7, 8, T1):
continuation/ terminal branch of
posterior cord of brachial plexus.
3. Course:
In the Axilla:
• RN lies anterior to
subscapularis, teres major
& lattisimus dorsi
• RN leaves the axilla via the
triangular hiatus
Motor supply: long head of
triceps
Sensory supply: posterior
cutaneous nerve of arm
4. In the Arm:
• Spiral groove (post.), accompanied
profunda brachi artery.
• Re-enters anterior compartment by
piercing lateral intermuscular septa
Motor supply: triceps, anconeus,
Brachioradialis, ECRL, Brachialis
Sensory : posterior cutaneous nerve of
forearm, lateral cutaneous nerve of arm
5.
6. In the Elbow:
• Anterior to lateral epicondyle, RN divides into its terminal
branches.
Posterior interosseous nerve
Superficial radial sensory nerve
radial nerve innervates the ECRL before it divides into its
two terminal branches: the posterior interosseous (motor)
and superficial (sensory) branches. Additionally, the ECRB
receives its innervation in most limbs (58%) from the
superficial radial nerve rather than from the posterior
interosseous nerve
7. The posterior interosseous nerve splays out into multiple thin
branches as it emerges from the supinator about 8 cm distal to the
elbow joint. Spinner has likened this to the cauda equina, and
repair of the individual branches is difficult. Difficulty in repairing
untidy injuries at this level often has an important influence on the
timing of tendon transfers.
8. In the Forearm:
• PIN reaches back of the forearm by passing around
lateral aspect of the radius b/w the two heads of
supinator.
• Lies b/w superficial & deep extensor muscles
• At distal border of EPB, passes deep to EPL,
descends on the interosseous membrane to
dorsum of the carpus- supply carpal ligaments &
articulations.
14. Radial nerve injuries
Aetiology
Humerus fractures(most common) – Holstein-Lewis fracture occur at the junction of
the middle and distal thirds of humerus. Fractures of the radial head and neck can
damage the posterior interosseous nerve.
Gunshot injuries
Injuries with sharp objects
Iatrogenic injury- surgical blades, K-wires,limb traction or fracture manipulation,
plates, screws and intramedullary nails, and poor positioning
15. Contd
posterior interosseous nerve is frequently injured during elbow surgery such as elbow
arthroplasty, radial head fracture repair and synovectomy. It also lies near the
anterolateral portal, and can be damaged during elbow arthroscopy – a rare
complication.
Compression neuropathies-
Saturday night palsy occurs when compression of the radial nerve at the spiral groove
of the humerus after prolonged pressure occurs.
Other causes of compression- fibrous arch of the lateral head of the triceps muscle,
within the fibrous arcade of Frohse( supinator arch)
16.
17. CLASSIFICATION
TRADITIONAL METHOD – not accurate
1)HIGH (Above elbow)- Elbow extension spared
2)VERY HIGH(involving triceps)- Crutch palsy, Aneurysms of axillary
artery
3)LOW (below elbow)
NEWER CLASSIFICATION
Complete radial nerve palsy vs PIN palsy (loss of finger extension)
18.
19.
20. HISTORY AND PHYSICAL EXAMINATION
Tinel sign
Wound Inspection- Tidy/Untidy
Neurological Examination- 1.Assessment of all muscles distal to injury
2. Sensory examination of affected dermatome
3. Assessment of invloved joints
Specific sensory tests- 1. Static two point discrimination (6mm) for tactile sensation
2. tuning fork tests 250hz for pacinian corpuscle
30hz for Meissner
3.Semmes Wienstein monofilament test for pressure (Merkel
cell)
21. ELECTRODIAGNOSTIC TESTING(EDT)
1. EMG(Electromyography)
2. NCS(Nerve Conduction Studies)
- For documentation and location of injury
- Severity of injury
- Recovery pattern
- Prognosis
- Selection of optimal muscles for tendon transfers
22. LIMITATIONS OF EDT
Only large myelinated fibres
Changes in unmyelinated fibres which are first to be affected
in nerve compressions are not evaluated
Very proximal or distal nerve injurues are difficult to assess
Unreliable assessment of multi-level injuries
Examiner dependant
23. NERVE CONDUCTION STUDY
2 electrodes are placed along the course
of the nerve. The first electrode
stimulates the nerve to fire, and the
second electrode records the generated
action potential.
Amplitude, latency, conduction velocity,
Sensory nerve action potential(SNAP),
Compound motor action
potential(CMAP)
29. TREATMENT
NON-OPERATIVE
Full passive range of motion in all joints of the wrist and hand,
prevention of contractures, including that of thumb index web.
Wrist drop can be treated by splints
Barkhalter has observed that grip strength can be increased to 3 to 5
times by simply stabilizing the wrist with splints.
35. NERVE REPAIR/GRAFTING VS TENDON
TRANSFERS
The time since injury is a critical factor, but late repair of the radial
nerve can produce reasonably good results at least in part because the
nerve is almost entirely motor.
However, if the prognosis for recovery of function after nerve repair is
poor, it would seem prudent to proceed directly to tendon transfers.
36. When attempting late repair, the surgeon must be prepared
to do nerve grafts if the gap is too great to overcome by
direct epineurial repair without tension. Several authors have
shown reasonable results with belated grafting of the radial
nerve. Samardzic and colleagues grafted gaps of 2 to 10 cm,
but Kallio and coworkers concluded that results were better
if the grafts were <5 cm.
38. Apparatus and Instruments for nerve
repair
DeBakey scissors and forceps are useful for handling nerves.
6-0 and 7-0 nylon on an 8-mm vascular needle is useful for epineurial
suturing
8-0, 9-0, and 10-0 should be used for perineurial suturing,for nerve
transfer, and in grafting.
Fibrin clot glue and commercial preparations.
Methods of Suturing
perineurial(i.e., fascicular) and epineurial sutures
Repair of the epineurium is important because it adds strength to the
repair
39.
40. Preparation of the Nerve Bed
The repaired nerve must not be left to lie against a naked tendon; the
synovium must be drawn together. Similarly, lacerated muscle belly is a
very unfavorable bed for a nerve repair, and rotation of either adjacent
synovium or undamaged fat should be done.
Unscarred synovium or fat is best—“raw” muscle is not a good bed; use of
bone or a metal implant is hopeless.
41. Preparation of nerve stumps 3 months after rupture of the
radial nerve. A, The rupture is displayed here. B, Resection was done
until clearly the separate pouting bundles were evident
42. Direct Suture or Graft?
End-to-end suture is preferable as long
as the gap after resection is small, little mobilization of the nerve
is needed to close the gap, and the repaired nerve lies without
tension and without excessive flexion of the adjacent joints.
Direct Suture
1.Primary suture when the operation
is performed within 5 days of injury
2.Delayed primary suture when up to 3 weeks has passed
3.Secondary suture is used for repairs performed 3 weeks or longer
after injury, and it involves resection of neuroma proximally
and glioma distally
43. Closure and Postoperative Care
Local anesthetic (0.5% levobupivacaine) instilled around stumps will greatly ease
postoperative Pain
The splint used should hold the elbow at 90 degrees of flexion, the wrist at between
30 and 40 degrees of flexion,MP joints at about 70 degrees of flexion, and the PIP
joints at no more than 30 degrees of flexion. The dorsal splint extends to the tips of
the fingers and the palmar splint to the PIP joints only.
Prolonged and careful protection of nerve repair is important; about 6 weeks is
needed for the upper limb and as long as 12 weeks for the lower limb.
44. At 3 weeks the splints and sutures are removed
The next splint does not restrict the elbow. The wrist is splinted to prevent
extension beyond 20 degrees. The dorsal hood, which again extends to
the tips of the fingers, limits the MP joints to 30 degrees of flexion and the
PIP joints to 30 degrees.
By 6 weeks the splints are discarded
45. Nerve Grafting
Choice of Graft
- medial cutaneous nerve of the forearm.
- longitudinal exposure
-The nerve is picked up with a light nerve hook and traced
proximally into the axilla while avoiding damage to adjacent
nerves.
-In the middle part of the arm divides into an anterior and
a posterior branch.
-It perforates the deep fascia shortly after this division.
-Both of the divisions are traced down to the level of the
elbow where about 25 cm of nerve can be obtained
46. sural nerve grafting
posterior midline longitudinal
incision that preserves the short
saphenous veins (above the lateral
malleolus, then trace it proximally)
It lies lateral to the short saphenous
vein until the nerve perforates the
deep fascia of the leg, generally at
the junction of the upper two-thirds
and the lower one-third of the limb.
47. TIMING OF TENDON TRANSFERS
Brown advised early transfers to restore wrist, finger, and thumb
extension when there was a poor prognosis for the radial nerve injury
and its repair.
He advised ignoring the nerve and proceeding directly to the tendon
transfers if there was a nerve defect of more than 4 cm, a large wound
or extensive scarring,or skin loss over the nerve.
48. if a good repair of the nerve is achieved, most would wait
several months (at least 5 or 6 after injury in the middle third
of the upper arm) to allow nerve regeneration to occur. They
would only proceed to tendon transfers if it was clear that
inadequate muscle reinnervation had occurred by both
clinical and electrodiagnostic criteria.
59. Brand’s biomechanical and clinical studies that led him to believe that
the FCU should not be used as a tendon transfer for two reasons:
(1) the FCU is too strong and its excursion is too short for
transfer to the finger extensors, and
(2) its function as the prime
ulnar stabilizer of the wrist is too important to sacrifice.
Despite these theoretical concerns, studies have shown no functional
loss of power grip with the FCU set.
61. World War I and World War II enabled a few individuals to
accumulate a lifetime of experience in a very short period,
and most of the articles that established the fundamentals of
transfers for radial nerve palsy were published in the immediate
postwar years.
67. The FCU tendon is transected just proximal to the pisiform and
freed up as far proximally as the incision allows. Separation of
this muscle from its particularly dense fascial attachments is
facilitated by a special tendon stripper designed by Carroll.
The limiting factor in the dissection is the innervation
of the FCU, which enters the muscle in its proximal 4 cm,
so the dissection must not extend this far proximally.
68. 1.PT TO ECRB
The tendon of the PT is identified in the palmar aspect of
the wound and followed to its insertion on the radius.
It is vital that the PT tendon be elongated by freeing up its
insertion with an attached long strip of periosteum.
The PT muscle and tendon are passed subcutaneously
around the radial border of the forearm, superficial to the
BR and ECRL, to be inserted into the ECRB just distal to its
musculotendinous junction.
69. Tension:
• Wrist in 45 degrees of extension
• PT under maximum tension
• If necessary, reinforce juncture with a strip of free tendon graft
73. Tension:
• Wrist in neutral (0 degrees)
• Maximum tension on distal stump of EPL
• PL under maximum tension
Absence of the palmaris longus. In this situation, several
authors have suggested including the EPL into the FCU-to-EDC
transfer, although this approach significantly limits thumb
abduction
75. POTENTIAL PROBLEMS
Excessive radial deviation after FCU harvest
Removing the FCU (an important wrist flexor and the only remaining ulnar deviator) from the wrist may
contribute to radial deviation.
Radial deviation is particularly severe in patients with posterior interosseous nerve palsy who have a
normally functioning , strong ECRL.
The “simplest” way to do avoid this is to resect the distal 2 to 3 cm of the ECRL tendon and suture the
tendon more proximally into the adjacent ECRB, eliminating any possibility of pull through the ECRL
insertion.
76. Superficialis Transfer (Boyes).
A long incision is made on the palmar-radial aspect of the mid-forearm,
and the tendons of the PT, ECRL, and ECRB are exposed.
A J-shaped incision is made on the dorsum of the distal
Forearm.
The FDS III is routed between the FDP and FPL.
The FDS IV is routed to the ulnar side of the profundus
muscle mass and both are then passed through the openings in
the interosseous membrane into the dorsum of the forearm
77. The FDS III is interwoven into the tendons of the EIP and EPL.
The FDS IV is interwoven into the EDC.
The tension is set with an assistant clenching the patient’s
fingers and thumb into a fist and bringing the wrist into 20
degrees of extension. This position is maintained until all the
transferred tendons are attached to their new insertions under
“considerable tension
78. Postoperative Management
Postoperative splints are applied and worn for 4 weeks, at which time the
sutures are removed and a splint is worn day and night.
except during exercise periods, for a further 2 weeks. All external support is
discontinued at 6 weeks postoperatively.
79. FCR TRANSFER
A straight longitudinal incision is made in the
distal half of the palmar-radial aspect of the
forearm between the FCR and PL.
The FCR is passed around the radial border of
the forearm through a subcutaneous tunnel,
which is created with a bluntnosed instrument
that probes natural tissue planes to find the
path of least resistance.
80. • Divide the EDC tendons just proximal to the retinaculum, and reposition
the stumps superficial to the retinaculum.
Tension:
• Wrist in neutral (0 degrees)
• MP joints in neutral (0 degrees)
• FCR under maximum tension
81. ARTICLES
Moussavi et al compared the use of FCR, FCU, or FDS III +
IV for restoration of finger extension in 41 Iranian patients with
isolated radial nerve palsies.They found no difference in the
outcomes of these three procedures, except that all three of
patients who were able to extend their fingers and wrist at the
same time had undergone FDS transfers. They reported mean
DASH scores of 30 to 38 for the three treatment groups and
that 30 of their 41 patients were able to return to work without
difficulty.
82. AUTHORS FAVOURED
METHOD(GREEN TEXTBOOK)
Favored transfers for restoration of function in radial
palsy are PT-to-ECRB, FCR-to-EDC, and PL-to-EPL.
I use FCR to-EDC and PL-to-EPL for posterior interosseous nerve palsies.
83. Radial Nerve Palsy Associated With
Fractures of the Humerus
Early Exploration of the Nerve
Holstein and Lewis advised early operative intervention for patients with
this fracture and an accompanying radial nerve palsy; however,
others have reported that early operative treatment is unnecessary,
including Szalay and Rockwood.
Nerve Exploration for Failure to Improve Spontaneously
The work of Seddon regarding nerve regeneration after axonotmesis
suggests nerve-fiber regeneration occurs at the rate
of approximately 1 mm/day following a latent period of 30
days
84. Nerve Transfer as an Alternative to Tendon
Transfer
Direct transfer of functioning, intact nerves to denervated muscles
(neurotization) is used to restore function in patients
with brachial plexus palsy when no other option is available.
The same concept has been reported in a few cases to restore
wrist, finger, and thumb extension in radial nerve palsy.
