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Ulnar
Nerve Surgery - Cubital Tunnel Syndrome
Cubital tunnel syndrome is a condition that involves
the ulna nerve as it crosses the elbow. Cubital tunnel
syndrome is the effect of pressure on the ulnar nerve,
one of the main nerves of the hand. It can result in
a variety of problems, including pain, swelling, weakness
or clumsiness of the hand and tingling or numbness of
the ring and small fingers. It also often results in
elbow pain on the side of the arm next to the chest.
Learn more about this condition in the "Anatomy
and Causes" section of this web site.
The condition can be treated with various procedures.
Learn about the various options below.
In
situ decompression
Indications for in situ decompression of the ulnar
nerve at the elbow are as follows:
- Mild ulnar nerve compression
- Documented mild slowing on EMG as the ulnar nerve
passes into and through the proximal FCU
- Absence of pain around the medial epicondyle
- A nerve that does not sublux with elbow flexion
- Normal osseous anatomy and retrocondylar groove
at the elbow and findings at surgery consistent with
compression under the fibrous arcade
Advantages of simple decompression are that it is simple
and easy to perform. The complication rate is low. In
contrast to other methods, in situ decompression avoids
damage to the vascular supply of the nerve. The operation
is less traumatic to the patient, and the documented
results are equally successful to those of other decompression
procedures. In situ decompression requires minimal or
no postoperative immobilization.
The advantages of the modified in situ technique include
the ability to release the ulnar nerve in areas of compression
with minimal disturbance of the blood supply. This procedure
avoids subluxation of the ulnar nerve, which may lead
to recurrence of symptoms secondary to repeated contusion
of the nerve as it snaps over the medial epicondyle.
The disadvantages of simple decompression are the potentially
higher recurrence rate and the risk of continued subluxation
of the ulnar nerve over the medial epicondyle, if that
was present preoperatively.
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Medial
epicondylectomy
The best indication for a medial epicondylectomy is
nonunion of an epicondyle fracture with ulnar nerve
symptoms. Other indications are a poor bed for the ulnar
nerve in the retrocondylar groove or ulnar nerve subluxation.
The advantages of a medial epicondylectomy are that
it provides a more thorough decompression of the ulnar
nerve than a simple release. This results in a minitransposition
of the ulnar nerve. Compared to an anterior transposition,
a medial epicondylectomy better preserves the blood
supply to the nerve, results in less injury to the nerve,
and preserves the small proximal nerve branches that
might be sacrificed with an anterior transposition.
The disadvantages of a medial epicondylectomy are that
it allows greater migration of the ulnar nerve with
elbow flexion. Potential exists for elbow instability
if the collateral ligaments are damaged. Bone pain and
nerve vulnerability at the epicondylectomy site may
occur. Compared to a simple decompression, the possibility
of elbow stiffness or an elbow flexion contracture developing
is greater. In addition, a medial epicondylectomy often
is a poor choice for athletes who throw because of the
significant stresses placed on the medial aspect of
the elbow joint.
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Anterior
transposition
The three types of anterior transposition are subcutaneous,
intramuscular, and submuscular.
Indications for an ulnar nerve transposition are an
unsuitable bed for the nerve secondary to the presence
of osteophytes, a tumor, a ganglion, an accessory anconeus
epitrochlears muscle, heterotopic bone, significant
bursal tissue or other mass. Other indications are significant
tension on the ulnar nerve as implicated with a positive
elbow flexion test result or symptoms aggravated by
activities requiring flexion, subluxation of the ulnar
nerve with elbow flexion, a deformity at the elbow secondary
to a valgus elbow or a tardy ulnar palsy, and the presence
of valgus instability at the elbow. Soft tissue coverage
must be adequate for the transposition of the nerve
and a medial elbow that is not subjected to repeated
minor trauma.
The advantages of an anterior transposition are that
it moves the ulnar nerve from an unsuitable bed to one
that is less scarred. The nerve is effectively lengthened
a few centimeters with transposition. This decreases
tension on the nerve with elbow flexion.
The disadvantages of an anterior transposition are
that it is a more technically demanding procedure than
a simple ulnar nerve decompression. The risk of complications
is increased when the nerve is moved from its natural
bed and there is a potential for devascularization of
the ulnar nerve.
With an anterior subcutaneous transposition, several
modifications are used to maintain the nerve in the
transposed position. These include the use of epineural
sutures, the creation of a fascial dermal or myofascial
sling, or the creation of a subcutaneous fascial sling.
A subcutaneous transposition may be the procedure of
choice in athletes who throw who do not have muscular
atrophy. These athletes may lose forearm strength from
a submuscular transposition and a simple decompression
may not provide adequate relief of symptoms.
The advantages of a subcutaneous transposition include
that it is easy to perform. It is a good procedure when
subluxation and traction on the nerve are contributing
to the patient's symptoms.
The disadvantages of a subcutaneous transposition include
that the nerve may be hypersensitive after surgery because
of its new superficial location. Potential exists for
disruption of the ulnar nerve blood supply with the
transposition.
Intramuscular transposition is the least popular decompression
method. It yields the fewest excellent results and the
most recurrences with severe ulnar nerve compression.
The advantages of an intramuscular transposition include
that it buries the nerve deeply, yet provides a tunnel
for the nerve to pass through. It also allows the nerve
to be entirely surrounded by vascularized muscle tissue.
The disadvantages of an intramuscular transposition
include that it is a complicated procedure. It involves
significant soft tissue dissection. Risk of perineural
scar is increased, and the procedure may expose the
nerve to repeated muscular contractions.
A submuscular transposition offers the best results
with the fewest recurrences with severe ulnar nerve
compression.
A submuscular transposition is the best salvage procedure
when previous surgery has failed because it places the
nerve in an unscarred bed. It also works well for patients
who are very thin, in whom a subcutaneous transposition
may result in an area of hypersensitivity over the transposed
nerve. Many consider it the procedure of choice for
symptomatic athletes who throw.
Contraindications for submuscular transposition include
significant scarring or distortion of the elbow joint
capsule, such as in a malunited fracture or in a patient
who has undergone excisional arthroplasty.
The disadvantages of a submuscular transposition are
that it is a technically demanding procedure. Because
of the extensive dissection, recovery for the patient
is more difficult and risk of elbow flexion contracture
is 5-10%. Patients also may develop extensive scar formation
from the procedure, and it is a difficult procedure
to revise if the patient has a recurrence.
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