Detailed description of median nerve injuries and management

1. Dr. Hardik Dodia

2. ANATOMY
 Roots from the lateral
(C5, 6, 7) and medial
(C8, T1) cords, which
embrace the third part
of the axillary artery,
and unite anterior or
lateral to it

3. COURSE IN THE ARM
 Enters the arm lateral to
the brachial artery.
 Near the insertion of
coracobrachialis ,crosses in
front of the artery
 Descending medial to it to
the cubital fossa where it is
posterior to the bicipital
aponeurosis and anterior
to brachialis, separated by
the latter from the elbow
joint.

5. COURSE IN THE FOREARM
• Enters the forearm
between the heads of
pronator teres .
• It crosses to the lateral
side of the ulnar artery,
from which it is
separated by the deep
head of pronator teres.

6. COURSE IN THE FOREARM
 Descends through the
forearm posterior and
adherent to flexor
digitorum superficialis
and anterior to flexor
digitorum profundus.

7. BRANCHES IN FOREARM
1) ANTERIOR
INTEROSSEOUS NERVE:
 Arises between two heads
of pronator teres
 Descends between and
deep to FPL and FDP along
with anterior interosseus
artery
 Supplies FPL, index+
middle finger FDP and
Pronator quadratus

8. 2) MUSCULAR BRANCHES to:
 Pronator teres
 Flexor carpi radialis
 Palmaris longus and
 Flexor digitorum superficialis.
3) OTHER BRANCHES:
 Articular branch
 Palmar cutaneous branch

9. AT WRIST
 5 cm proximal to the flexor
retinaculum it emerges
from behind the lateral
edge of FDS
 Lies between the tendons
of flexor digitorum
superficialis and flexor
carpi radialis
 Passes laterally from
beneath the tendon of PL,
deep to retinaculam

10. IN HAND…
MOTOR BRANCHES
 Thenar muscles
 First two lumbricals
SENSORY SUPPLY
 Digital branches

11. 3) Branches in the hand:
1) the lat .terminal branch :
A) 3 common palmer digital branches.
B) recurrent muscular branch.
2) the med . Terminal branch :
It gives 2 common palmer brs :
-The lat. Branch.
-The med. Branch.

14. 6) Its End

15. -Main trunk :
All superficial muscles of the front of the forearm
except flex. Capri ulnaris.

16. - Ant. Interosseous br.:
- supplies 2 ½ muscles :
All deep muscles of the front of forearm except
the med. ½ of flex. Digit. Profound.
Lat. Terminal br : 4 muscles
i.e. the 1st lumbrical m + all thenar m (except add .poll.)
Med. Terminal br.: 2nd lumbrical m

17. -The palmer cutaneous br.: Arises in the lower
end of forearm & descends to the hand to supply the
skin of the lat. 2/3 of the palm.
Lat. Terminal br.
Gives 3 palmer digital branches
Med. Terminal br.:
Gives 2 palmer digital brs.

18. -
-Main trunk
Supplies elbow & sup. Radioulnar joint .
-Ant. Interosseous
Supplies wrist & inf . Radioulnar joint

19. To the radial &
ulnar arteries.
So patients with
lesions
Dry scaly skin
and brittle
nails.

20. Topographic Anatomy

22. ETIOLOGY
 Trauma
 Leprosy
 Carpal tunnel syndrome
 Poliomyelitis
 Neurological Ds- Spinal muscular atrophy
Syringomyelia
Congenital absence of thenar muscle

23. CLASSIFICATION
HIGH LOW
 Lesion is at or proximal to the
origin of anterior interosseus
nerve in the proximal forearm
 PL, PT, FCR, FDS, index and
middle finger FDP, FPL and
the PQ muscles are paralysed.
 Lesion is distal to the origin
of anterior interosseus nerve
 APB, superficial head of FPB
and Opponens pollicis are
paralysed.

24. (1) Paralysis of all muscles supplied .
(2) loss of pronation of the forearm .
(3) weak flexion of the wrist .
(4) loss of the flexion & opposition of the thumb.

25. (1) hyper-extended thumb .
(2) adduction .
(3) flat thenar eminence .
- lat. 2/3 of the palm of the hand .
-lat. 3 ½ fingers anteriorly & their distal
halves posteriorly.

26. - lat. 2/3 of the palm of the hand .
-lat. 3 ½ fingers anteriorly & their distal
halves posteriorly.
-Paralysis of the 5 hand muscles supplied by the
nerve.
-The forearm muscles escape the injury as they are
supplied at elbow.

29. CLINICAL EXAMINATION
 Pointing index finger – FDS and FDP
 Ulnar deviation of wrist while flexing it - FCR
 Pen test – APB
 Ape thumb deformity – Opponens Pollicis

30. Work up
Radiographs
• X ray of arm and forearm to detect or rule out a
fracture
EMG and NCV study
Performed initially to provide a baseline, but
unless the nerve is severed, no changes will be
observed for 3-6 weeks.
• Help to locate the site of injury
• Help to monitor the nerve recovery over time.

32. Timing of nerve repairs
Open injuries
 Require early exploration.
 Sharp lacerations can be repaired immediately and directly.
 Wound must be relatively clean and free of gross
contamination.
 A primary repair is not recommended with injuries
secondary to a crush injury /significant soft tissue damage.
 At 3 weeks (or when the wound permits), the nerve is re-
explored, and definitive repair or graft can be performed.
 At that time, the zone of injury is apparent based on the
extent of scar formation.

33. Closed injuries
 In closed or blunt trauma, initial management is
expectant with close observation.
 If complete recovery is not observed within 6 weeks,

 Electrodiagnostic studies should be obtained for
baseline evaluation.

34.  Monthly clinical and EMG evaluation

 If motor unit potentials are seen with EMG, ►
spontaneous reinnervation is anticipated,
 Lack of clinical or electrical evidence of
reinnervation at 3 months requires operative
exploration.

35. Principles of nerve repair
 The results have improved with the advent of
microsurgical techniques.
1)Quantitative pre-operative assessment of motor and
sensory systems
2)Microsurgical technique including proper
magnification, instrumentation, and microsutures
3)Tension-free repair-prime object
4)When a tension-free direct repair is not technically
possible, use of an interpositional nerve graft
5)Primary repair when the conditions permit

36. 6)Postural manuevers can’t substitute tension free repair
7)Fascicular repair when fascicular anatomy discernible
and epineural repair when it is indiscernible
8)Delay in repair for approximately 3 weeks in cases
where primary repair is not optimal (e.g, with a severe
crush, stretch, or loss of nerve tissue)
9)Early protected range of movement to allow nerve
gliding
10)Post op physiotherapy to maintain range of motion
and assist in postoperative sensory and motor re-
education and rehabilitation to maximize the clinical
outcome

38. Biomechanics and deformity
 Thumb opposition is a complex movement requiring
trapeziometacarpal (CMC) joint abduction, flexion, and
pronation.
 Abduction, Pronation flexion at CMC joint
 Abduction and flexion at MCP joint
 Flexion and Extension at IP joint
 Axial thumb rotation, usually 90 degrees of pronation and
60 degrees of supination.
 Prime muscle of thumb opposition is the APB, although
both the opponens pollicis and FPB also produce some
opposition.

44.  Considerable diversity in the pattern of innervation-
reason behind intact opposition after isolated MNP
 Superficial head of the FPB has dual median and ulnar
innervation in 30% of hands, whereas its deep head
has dual innervation in 79% of cases
 Oblique head of the adductor pollicis has dual ulnar
and median innervation in 35% of cases
 Thenar muscles sometimes do have dual nerve supply
from ulnar nerve.

45.  Martin Gruber Anastomosis- motor nerve
interconnection between median (or anterior
interroseus) and ulnar nerve in proximal forearm.
 17 percent of people have it.

46. Restoration of functions
 Restore Sensation by primary repair of nerve
 Restore thumb functions Opponens plasty
 In high Median nerve lesions- Restore FPL, Index
finger Digitorum and Opponens plasty.
 Restoration of all this function requires tendon
transfer

47. Tendon Transfer principle
 Supple Joints
 Soft tissue equilibrium
 Adequate Excursion
 Appropriate Strenght of Donor
 Expendable Donor
 Straight line of pull
 Synergy
 Single transfer Single Function

49. Surgeon must have a clear picture of the
functional disability
 Indication for an opponensplasty is loss of
function due to loss of opposition
 Careful patient counselling about the possible
functional benefit, the rehabilitation process,
and the likely outcome of surgery is mandatory
 If there is also loss of, or absent, sensation in the
median nerve territory, this may reduce any
potential benefit of an opponensplasty

50. Prevention and Preoperative
Treatment of Contractures
 It is always easier to prevent a soft tissue contracture
than to correct an established one
 Prevented by passive thumb abduction and opposition
exercises and by abduction splints
 Temporary internal splintage of the thumb
metacarpal in abduction with a K wire may be
indicated
 Established soft tissue contractures must be corrected
by releasing skin, fascia over Ad PL , first dorsal
interossei ,joint capsule or joint itself

52. Selection of motor
 Muscle selected for opponensplasty must be
expendable, and this muscle must have strength and
potential excursion similar to that of the APB and
opponens pollicis muscles
 Should have a tension fraction similar to that of the
combined APB and opponens pollicis tension (1.1 + 1.9
= 3.0) and a muscle fiber length that is at least as long
as that of the APB-3.7 cm
 Avoid tendon graft

53. Pulley design
 Hypothenar fibrous raphe
 Around FCU tendon
 Hooked FCU tendon
 Distal FCU strip attached to ECU
 Angle between PL and flexor retinaculam
 Window in flexor retinaculam

54. Four standard
opponensplasties
 Superficialis opponensplasty:
1)Royle-thompson technique
2)bunnell technique
 Burkhalter EIP opponensplasty
 Huber ADM transfer
 Camitz opponensplasty (palmaris longus)

55. SUPERFICIALIS opponensplasty
Superficialis tendon harvest:
Royle and thompson both divided ring finger
superficialis tendon at its middle phalnyx insertion
North and Littler recommended division proximal to
its bifurcation through window between A1 and A2
pulleys with finger fully flexed

56. Royle-Thompson opponensplasty:
 Ring finger FDS as motor
 Angle between flexor retinaculam & palmar
aponeurosis as pulley
 Inserted on insertion of APB
 Attachment to the thumb is then sutured while the
thumb is held in full opposition and the wrist is in
neutral for 4-6wks

57. Bunnell’s opponensplasty
 Ring finger FDS through FCU pulley made from distal
4 cm of FCU tendon
 Inserted with a dorsoulnar-venteroradial drill hole at
base of proximal phalanx
 Thumb immobilised in full opposition with neutral
wrist for 4-6 weeks
 DEMERITS OF SUPERFICIALIS TRANSFER:
Not useful for high MNP

60. Burkhalter EIP opponensplasty
 EIP divided proximal to extensor hood, retrived
proximal to extensor retinaculam
 Tunelled superficial to FCU with ulnar border of wrist
as pulley
 Distal attachment:
Isolated MNP-APB
Immobilise thumb in full opposition with 30 degree
wrist flexion

63. Advantage:
 Useful for both high and low MNP
 More stable, adjustable natural pulley
 Easy to perform
Disadvantage:
short fiber length of EIP

64. Huber’s ADM opponensplasty
 Two insertion divided along with pisiform attachment,
leaving behind FCU attachment and pedicle
 No pulley needs to be used, turned 180* to insert on APB
 As having only sufficient length, invariably remain in
adequate tension. Used mostly in patients with congenital
thenar atrophy as it gives bulk to thenar territory
 Splinted post op for 3-4 wks
DISADVANTAGE:
 Difficult to perform
 Critical blood supply

67. Camitz PL opponensplasty
 For carpal tunnell syndrome, done simultaneous with
decompression
 Conform position of tendon preop
 Avoid injury to palmar cutaneous branch of median
nerve
 Divide tendon with 1 cm strip of aponeurosis and
inserted on APB/ EPB/ MP joint capsule, no pulley
used

71. OTHER OPPONENSPLASTIES
 ECU OPPONENSPLASTY
 ECRL OPPONENSPLASTY
 EDM OPPONENSPLASTY
 COMPROMISE OPPONENSPLASTY
EPL/FPL opponensplasty

74. Post op management
 Thumb immobilized in opposition for 3 wks after most
opponensplasty with cast/ cyanoacrylate glue
 Wrist immobilized in neutral, as, extrinsic tendons
crosses wrist. Transfer of muscles with short
excursions, like, EIP, should be relaxed by wrist in 30*
flexion
 Early thumb & wrist movement emphasised after
3wks,except, high MNP+ UNP/profound sensory loss
like in leprosy-protect Camitz PL opponensplasty for
up to 3mth

75. HIGH MEDIAN NERVE PALSY
THUMB OPPOSITION:
 Pt use APL and extrinsic extensors to position their
thumb when picking up an article from flat surface
 Thumb remain in supination and extension, pt
pronate hand either by pronating forearm or internally
rotating shoulder-so, can’t use sight as substitute for
sensory loss-so, few recommend early opponensplasty
 EIP,EPL and EDM are most readily available

76. HIGH MEDIAN NERVE PALSY
Timing and selection of transfer:
 Prime aim is to restore thumb+ index finger flexion with
opposition
 BR,ECRL and ECU-available options, ECU may be required
for opponensplasty-all three having excursion less than
recipient
 Sensory loss is most imp single disability, some believe it
strong contraindication
 Due to poor recovery in sensory fn and opposition after
nerve repair, early transfer less recommended
 Transfer only if after max recovery, pt and surgeon believe it
as cause of debility and it will improve hand function

77. INDEX FINGER FLEXION:
 Only in pts who need strength on radial side of hand
 ECRL to Index Profundus transfer/side-to-
sidesuturing with other finger profundus tendons in
distal forearm
 For ECRL transfer, tension is adjusted when finger is
fully extended with wrist flexed 30* to avoid excess
tension

80. THUMB FLEXION:
 To achieve 30 mm excursion , BR muscle
freed in distal 2/3 forearm
 Tension set as above
 Because, BR is primarily elbow flexor, weak
thumb flexion when elbow flexed

81. COMPLICATIONS
Aggravation of Swan neck deformity:
 Special consideration for pts with hyperextensible
joints-
 1)transfer of ECRL to index and middle finger FDS
 2)transfer of ECRL to index and middle finger FDP
with FDP sutured to A4 pulleys
 3)transfer of ECRL to index and middle finger FDP
with DIP joint arthrodesis

82. CONCLUSION
 TENDON TRANSFER CAN RESTORESELECTEDMOTOR FN
AFTER HIGH AND LOW MNP, BUT THEIRABILITY
RESTRICTED BY SEVERITY OF SENSORY LOSS
 EIP/PLTRANSFER IMP FOR LOW PALSY AND
SIMULTANEOUS BR/ECRL TRANSFER FORHIGH PALSY

83. Nerve Transfers

84. Motor roots
1) Radial ECRB to AIN
2) Musculocutaneous Brachialis branch to AIN

87. Sensory roots
 Dorsal cutaneous branch of ulnar nerve coapted with
end to side with radial side of median nerve to restore
first web space function.
 Distal third webspace is end to side with ulnar nerve

89. MEDIAN NERVE COMPRESSION
NEUROPATHY
 CARPAL TUNNEL SYNDROME
 PRONATOR TERES SYNDROME
 ANTERIOR INTERROSEUS SYNDROME

90. It is compression of median n. as it passes through the
carpal tunnel.
(1) dislocation of one of the carpal bones.
(2) thickening of the tendons passing.
(3) myxoedema or tumour inside the carpal tunnel .

91. As in the injury below the elbow but there is no sensory
loss in the palm because the palmer cutaneous br . Passes
outside the carpal tunnel.
The characteristic deformity of all median n.
injuries is monkey hand.

92. Atrophy

96. CLINICAL FEATURES
 SYMPTOMS
Pain
paresthesia
tingling
Awakens the pt. at night
 SIGNS
Decreased grip strength
Thenar muscle atrophy
Tinels sign

97. MANAGEMENT
conservative
- General measures
- Splints
- Oral medications
- Local injection
- Ultrasonic therapy
Surgery – Division of tranverse carpal ligament

98. PRONATOR SYNDROME
 Ligament of Struthers. (Most common)
 Anamolous bony spur in supracondylar process.
 Bicipital aponeurosis.
 Symptomatic treatment
 Correction of cause

100. Anterior interosseus syndrome
 Accesory head of FPL
 Fibrous arch of FDS
 Aberrant palmaris profundus
 Fascial bands of deep head of pronator teres
 Symptomatic treatment
 Correction of the cause

102. .