3. Surgical anatomy
• Medial cord
• Nothing in the arm
• Crosses behind the elbow in the
cubital tunnel
• Under FCU
• Supplies 1&1/2 muscles
• Crosses in to the hand out side
the carpal tunnel
4. Classification of Nerve injury
Seddon’s classification system
• Neurapraxia
• Axonotmesis
• Neurotmesis
Sunderland’s classification system
Grade 1-5
Modification (mackinnon)
Grade 6
8/22/2015 8:51 PM 4
7. Ulnar nerve injury
• Frequently injured at the medial epicondyle or at the wrist
• Types
• At wrist: 'low'
• At elbow 'high
8. • High-level ulnar nerve lesions
• all injuries to the nerve proximal to the innervation of the FCU and
FDP.
• Patients with such injuries present with
• an absence of sensation in the small finger and ulnar half of
the ring finger,
• loss of the intrinsic motors in the hand
• loss of motor function in the FDP to the small and ring
fingers.
9. • Low-level ulnar nerve lesions
• occur distal to the innervation of the FCU and FDP.
• This lesion presents with similar sensory deficits, although the
dorsal sensory branch might be spared and dorso ulnar hand
sensation thus preserved.
• clawing is more pronounced than in patients with high ulnar
nerve lesions
• Wrist flexion strength is maintained through a functional FCU.
10. Clinical Signs
• There are many clinical signs and specific tests for loss of ulnar
nerve motor function
• (Duchenne’s sign)
• Froment’s
• Wartenberg’s sign
• is inability to adduct the extended little finger to touch the extended ring
finger
11. Factors influencing ulnar nerve repair
• The age of the patient
• The level of injury
• The delay between the time of injury and repair
• The nature and extent of the injury can also affect the outcome
• The experience and techniques of the surgeon
12. Timing Of The Nerve Repair
• Sharply transected nerves
• Immediate repair
• Crushed, avulsed, blast injuries
• Nerve ends tacked together
• Repair delayed for 3 weeks or until wound bed permits
• Re-exploration
• Neuroma excision, nerve grafts
• Bleeding control ,trimming of fascicles ,loose epineural suturing
• Closed injuries treated expectantly for 12 weeks
14. • Low-level lesions
• frequently occur just proximal to
the wrist.
• Release of the carpal tunnel and
Guyon’s canal aids exposure of
the nerve and mobilization to
reduce gapping at the repair site.
• Wrist flexion frequently is required
to facilitate the repair
15. Summary
• Patient age, the site and extent of the injury, and the delay of
treatment significantly influenced the outcome after repair of ulnar
nerve injuries
• High-level lesions and lesions that are close to the elbow can also
benefit from nerve transposition
• Splinting wrist flexion and/or elbow extension with carpal tunnel and
Guyon’s canal releases are necessary for lesions that are closer to the
wrist
16. references
• H. James Pfaeffle, MD, PhD, Thanapong Waitayawinyu, MD,Thomas E.
Trumble, MD* Ulnar Nerve Laceration and Repair
• Birch R, Raji AR. Repair of median and ulnar nerves: primary suture is
best. J Bone Joint Surg Br 1991;73(1):154–7
• Gelberman R. Operative nerve repair and reconstruction, vol. 1.
Philadelphia: JB Lippincott; 1991.
• Ruijs AC, Jaquet JB, Kalmijn S, et al. Median and ulnar nerve injuries: a
meta-analysis of predictors of motor and sensory recovery after
modern microsurgical nerve repair. Plast Reconstr Surg 2005;
116(2):484–484
Editor's Notes
A first-degree injury or neurapraxia involves a temporary conduction block with demyelination of the nerve at the site of injury. Electrodiagnostic study results are normal above and below the level of injury, and no denervation muscle changes are present. No Tinel sign is present. Once the nerve has remyelinated at that area, complete recovery occurs. Recovery may take up to 12 weeks.
A second-degree injury or axonotmesis results from a more severe trauma or compression. This causes Wallerian degeneration distal to the level of injury and proximal axonal degeneration to at least the next node of Ranvier. In more severe traumatic injuries, the proximal degeneration may extend beyond the next node of Ranvier. Electrodiagnostic studies demonstrate denervation changes in the affected muscles, and in cases of reinnervation, motor unit potentials (MUPs) are present. Axonal regeneration occurs at the rate of 1 mm/d or 1 in/mo and can be monitored with an advancing Tinel sign. The endoneurial tubes remain intact, and, therefore, recovery is complete with axons reinnervating their original motor and sensory targets
A third-degree injury was introduced by Sunderland to describe an injury more severe than second-degree injury. Similar to a second-degree injury, Wallerian degeneration occurs, and electrodiagnostic studies demonstrate denervation changes with fibrillations in the affected muscles. In cases of reinnervation, MUPs are present. Regeneration occurs at 1 mm/d, and progress may be monitored with an advancing Tinel sign. However, with the increased severity of the injury, the endoneurial tubes are not intact, and regenerating axons therefore may not reinnervate their original motor and sensory targets.
The pattern of recovery is mixed and incomplete. Reinnervation occurs only if sensory fibers reach their sensory end organs and motor fibers reach their muscle targets. Even within a sensory nerve, recovery can be mismatched if sensory fibers reinnervate a different sensory area within the nerve's sensory distribution. If the muscle target is a long distance from the site of injury, nerve regeneration may occur, but the muscle may not be completely reinnervated due to the long period of denervation.
A fourth-degree injury results in a large area of scar at the site of nerve injury and precludes any axons from advancing distal to the level of nerve injury. Electrodiagnostic studies reveal denervation changes in the affected muscles, and no MUPs are present. A Tinel sign is noted at the level of the injury, but it does not advance beyond that level. No improvement in function is noted, and the patient requires surgery to restore neural continuity, thus permitting axonal regeneration and motor and sensory reinnervation.
A fifth-degree injury is a complete transection of the nerve. Similar to a fourth-degree injury, it requires surgery to restore neural continuity. Electrodiagnostic findings are the same as those for a fourth-degree injury.
A sixth-degree injury was introduced by Mackinnon to describe a mixed nerve injury that combines the other degrees of injury. This commonly occurs when some fascicles of the nerve are working normally while other fascicles may be recovering, and other fascicles may require surgical intervention to permit axonal regeneration.
The ulnar nerve is most commonly injured at the elbow, where it lies behind the medial epicondyle,
The injuries at the elbow are usually associated with fractures of the medial epicondyle.
At the wrist, where it lies with the ulnar artery in front of the flexor retinaculum.
The superficial position of the nerve at the wrist makes it vulnerable to damage from cuts and stab wounds
Weakness of the intrinsic musculature results in clawing of the small and ring
fingers with metacarpophalangeal (MCP) joint hyperextension and proximal interphalangeal joint
flexion
Low level
Paralyzes intrinisic hand muscles except thenar eminence & lumb 1,2
Inability to abduct or adduct fingers(introssei muscles)or adduct thumb(aductor polices muscle
Causes claw hand characterised by wasted hypothenar muscles ,hyperextended MCP joints and flexed PIP & DIP joints of fingers 4&
Because FDP function is intact, clawing is more pronounced than in patients with high ulnar nerve
lesions because of the intact flexor tone at the small
and ring finger interphalangeal joints with loss of
tone at the MCP joints
(Duchenne’s sign)
Clawing, with hyperextension at MP joints and flexion at IP joints, is the characteristic resting posture of the ring and little fingers
Froment’s sign—marked thumb IP joint flexion when pinching sheets of paper between the thumb and index finger—indicates paralysis of the adductor pollicis and first dorsal interosseous muscles, with replacement of their pinch function by the FPL
Wartenberg’s sign
is inability to adduct the extended little finger to touch the extended ring finger. This is due to the EDM abducting the little finger (despite paralysis of the hypothenar muscles)
Many factors affect the outcome of peripheral nerve repair
Patient age has been shown to be the most important
factor, with younger patients achieving better results[3–5,7]. High-level lesions rarely regain motor function after a repair [4]. Delay in diagnosis
or treatment is another important factor
High-level lesions are treated with subcutaneous transposition to help reduce tension on the
After repair, the nerve is prevented from
returning to the cubital tunnel with a dermofascial sling by suturing a flap of fascia from the
flexor pronator origin to the subcutaneous tissue
on the anterior flapThe laceration is extended in a longitudinal fashion (Fig. 5), and subcutaneous flaps are created.
As with lacerations at more proximal levels, we perform longitudinal extensions to gain exposure (Fig. 7). The closer the injury is to the palm, the
reater the need is for carpal tunnel release, and it is helpful to plan the incision with that in mind. Blunt dissection is used to identify the nerve
outside the zone of injury. Guyon canal is then released by incising the palmar carpal ligament
Splinting wrist flexion and/or elbow extension with carpal tunnel and Guyon’s canal releases are necessary for lesions that are closer to the wrist.
Arterial repairs combined with nerve repairs especially in low-level injury can provide superior outcomes
