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June 1998
Volume 62 |
Number 6
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| Perioperative
Ulnar Nerve Injury - A Continuing Medical and Liability Problem |
Frederick W. Cheney, M.D., Director
ASA Closed Claims Project
Data from the ASA Closed Claims Project continues to indicate
that severe anesthesia-related injuries such as death and brain
damage are becoming less frequent.1
This is not the case, however, with anesthesia-related perioperative
nerve injury.
In 1990, we first reported an analysis of anesthesia-related
nerve injury claims from the ASA Closed Claims Project, which
is a standardized collection of adverse anesthesia-related outcomes
collected from the closed malpractice claims of 35 insurance organizations.2
Of 1,541 total anesthesia claims in the database in 1990, 15 percent
were for nerve injury with 34 percent of the total nerve injuries
being of the ulnar nerve.2 Of the
2,642 claims added to the database since that time, 17 percent
(n = 445) were for nerve injury. The most common nerves involved
are shown in Table 1.
Table 1
Most Frequent Claims for Nerve Injury by Gender
| Nerve |
# Claims |
% of 445 |
% Female |
% Male |
| All nerve damage claims |
445 |
>
100% |
49% |
51% |
| Ulnar Nerve |
113 |
25% |
21% |
79% |
| Brachial Plexus |
83 |
19% |
57% |
43% |
| Spinal Cord |
73 |
16% |
49% |
51% |
| Lumbosacral |
| Nerve Root |
67 |
15% |
70% |
30% |
| Sciatic Nerve |
23 |
5% |
61% |
39% |
Ulnar nerve injury accounted for 25 percent (n = 113)
of the total nerve injuries with a heavy male predominance as
compared with injuries to other commonly affected nerves (Table
1). General anesthesia was used in 86 percent (n = 97) of the
claims for ulnar nerve injury while in the remainder of the ulnar
nerve claims, regional or local anesthesia was utilized.
The mechanism of ulnar nerve injury was rarely explicitly
stated in the claim file, as was the case in our earlier report.
This occurred in spite of the fact that the closed claims reviewed
after 1990 contained much more information than those in the original
report. The mechanism was apparent in 12.3 percent (n = 14 of
113) of claims for ulnar nerve injury. Of these 14 claims, the
injury was clearly pre-existing in nine, one was related to the
surgical procedure, another due to the use of crutches and three
were associated with the performance of an axillary block. Paresthesias
were not present during performance of the block in any case.
It is remarkable that the mechanisms of anesthesia-related
ulnar nerve injury usually cited in the literature were never
explicitly stated in any claim file in spite of intensive medicolegal
investigation.3,4 Anesthesia-related
perioperative ulnar nerve injury is often ascribed to malposition
of the elbow with the ulnar nerve being compressed during surgery
on a hard surface, or stretched in some fashion. It is notable
that in 28 of the 113 claims (25 percent), extra padding over
the elbows was explicitly noted in the file. This casts some doubt
on the commonly cited nerve compression mechanisms of intraoperative
anesthesia-related ulnar nerve injury.
Further evidence against an all-inclusive malposition
nerve compression theory of causation is the fact that eight claims
for perioperative ulnar nerve injury were from patients who had
spinal, epidural or local anesthesia for lower body surgical procedures.
All were awake or sedated during the surgical procedure, with
signs and symptoms of the ulnar neuropathy usually becoming apparent
one to four days after surgery. It would seem reasonable that
an awake or lightly sedated patient would be aware of compression
or stretch of the ulnar nerve extreme enough to cause injury.
It is instructive to consider some of the key factors
that influence the way in which claims for ulnar nerve injury
are often resolved. Because the mechanism of ulnar nerve injury
is not usually apparent, plaintiff's attorneys sometimes try to
invoke the legal doctrine of "res ipsa loquitor" (the thing speaks
for itself). Strictly speaking, the doctrine of res ipsa loquitur
applies to situations in which four criterion are satisfied: 1)
the injury is not expected to arise except from negligence, 2)
the mechanism of injury is under the exclusive control of the
physician, 3) the patient does not contribute to the mechanism
of injury, and 4) the explanation for the injury is more accessible
to the physician than the patient. Without the doctrine of res
ipsa loquitur, the plaintiff bears the burden of proof to show
that negligence was the cause of injury. When the doctrine of
res ipsa loquitur is invoked, the situation is reversed and the
defendant must show that care was not negligent.
Ulnar nerve injury cases are often "custom made" for the
doctrine of res ipsa loquitur because it is easy for the plaintiff
to find medical experts who will testify that 1) those injuries
only arise if the patient is positioned or monitored in an incorrect
or negligent manner and 2) the cause of the injury is most likely
related to some aspect of medical care. Although judges rarely
permit the res ipsa doctrine in nerve injury cases, the plaintiff's
attorneys and plaintiff's experts usually present similar arguments,
thus accomplishing the same result. Most cases are settled short
of the courtroom, but this is the background against which many
of these claims are resolved.
The combination of lack of apparent mechanism of injury
and the willingness of experts to attribute ulnar neuropathy to
improper positioning and padding leads to an interesting relationship
between standard of care and payment for the injury. In 76 percent
of the claims, the closed claims reviewers judged the care as
having met the appropriate standard, while the care was judged
as inappropriate or substandard in only 6 percent of the cases
[Table 2]. One would expect that, with the care being judged as
appropriate in most cases, payment to the plaintiff would rarely
be made. This was not the case, however, as payment was made in
about half of the claims where care was judged appropriate. Payment
was even made in 50 percent of the claims where the patient was
awake or sedated during regional anesthesia and surgery performed
on the lower body.
Table 2
Incidence of Payments for Ulnar Nerve Injuries
|
|
Incidence of Payment(a) |
| Standard of Care |
n |
% Total |
n |
%(b) |
Median Payment |
| Standard |
86 |
76.1% |
35 |
40.7% |
$29,500 |
| Substandard |
7 |
6.2% |
5 |
71.4% |
$75,000 |
| Unable to Judge |
20 |
17.7% |
10 |
50.0% |
$55,000 |
a.payment data missing in 14 claims
b.% based on number of ulnar nerve injury claims in care group |
On the other hand, payment was made in five of the seven
claims where care was judged inappropriate. Inappropriate care
did seem to command a higher median payment although the number
of paid claims (n = 5) in the group is too small for statistical
comparison. While median payment for all ulnar nerve injuries
was $34,375, when care was judged inappropriate it was $75,000
[Table 2].
Clearly, factors other than appropriateness of care influence
whether or not payment is made. These include the persistence
and skill of the plaintiff's attorney, the willingness of the
insurance company to pay for the nuisance value of a claim and
the economic effect of the injury on the claimant's employment
and lifestyle.
In conclusion, anesthesia-related perioperative nerve
injury presents a perplexing problem for the anesthesiologist
because the mechanism of the injury is unclear and preventive
strategies are not apparent. Because the injury has a relatively
low overall incidence (1 in 2,729 patients in a general surgical
population),5 prospective studies
of any preventative measures would be exceedingly difficult to
do. In our 1990 report, we made the statement that: "In certain
susceptible patients nerve injury may occur in spite of conventionally
accepted methods of positioning and padding."2 Unfortunately,
that statement is still true today.
References:
- Cheney FW. Anesthesia patient safety and
professional liability continue to improve. ASA NEWSLETTER.
1997; 61(6):18-20.
- Kroll DA, Caplan RA, Posner K, Ward RJ, Cheney
FW. Nerve injury associated with anesthesia. Anesthesiology.
1990; 73:202-207.
- Britt BA, Joy N, Mackay MB. Anesthesia-related
trauma caused by patient malpositioning, In: Gravenstein N,
Kirby RR. eds. Complications in Anesthesiology. 2nd ed.
Philadelphia: Lippincott-Raven; 1996:365-389.
- McAlpine FS, Seckel BR. Martin JT. ed. Complications
of positioning: The peripheral nervous system. In: Martin JT.
ed. Positioning in Anesthesia and Surgery. 2nd ed. Philadelphia:
W.B. Saunders Co; 1987:303-328.
- Warner MA, Warner ME, Martin JT. Ulnar neuropathy.
Anesthesiology. 1994; 81:1332-1340.
Frederick W. Cheney, M.D., is
Professor and Chair, Department of Anesthesiology, University
of Washington School of Medicine, Seattle, Washington.
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