Journal of the American Academy of Orthopaedic Surgeons
336
The symptom complex of pain,
numbness, tingling, and paresthe-
sias in the anterolateral thigh not
associated with a surgical procedure
was first described by Bernhardt in
1878. In 1885, Hager was the first to
postulate that compression of the
lateral femoral cutaneous nerve
(LFCN) was the cause of the pain.
In 1895, Roth reported on five pa-
tients with similar presentations
and initially coined the term “meral-
gia paresthetica” from the Greek
words meros (“thigh”) and algos
(“pain”). Perhaps the most famous
case is that of Sigmund Freud, who
described symptoms in himself as
well as in one of his sons.
1
Anatomic Considerations
Familiarity with the underlying
neuroanatomy of the affected region
is key to understanding the patho-
logic changes that occur in meralgia
paresthetica. In particular, the ori-
gin of the LFCN and its relation to
the other structures about the ilium
are characteristics that must be con-
sidered.

The LFCN is an entirely sensory
nerve that is usually derived from
one of several different combina-
tions of the lumbar nerve roots,
including L1 and L2, L2 and L3, and
L3 alone.
2
Piersol reported that the
LFCN can also be partially or entirely
derived from adjacent peripheral
nerves, such as the genitofemoral
and femoral nerves.
3
Keegan and
Holyoke
4
reported LFCN variation
in 30% of 50 cadaveric dissections.
The nerve emerges from the lat-
eral aspect of the psoas muscle. It
runs beneath the iliac fascia as it
crosses the anterior surface of the ili-
acus muscle and travels along this
retroperitoneal route across the
ilium toward the anterior superior
Dr. Grossman is Orthopedic Sports Medicine
Fellow, Kerlan-Jobe Orthopedic Clinic, Los
Angeles, Calif. Dr. Ducey is in private prac-
tice in Bellville, NJ. Dr. Nadler is Attending
Physician, Department of Physical Medicine

and Rehabilitation, New Jersey Medical School,
Newark. Dr. Levy is in private practice in
Summit, NJ.
Reprint requests: Dr. Grossman, Kerlan-Jobe
Orthopedic Institute, Suite 125, 6801 Park
Terrace, Los Angeles, CA 90045.
Copyright 2001 by the American Academy of
Orthopaedic Surgeons.
Abstract
Meralgia paresthetica is a symptom complex that includes numbness, paresthe-
sias, and pain in the anterolateral thigh, which may result from either an
entrapment neuropathy or a neuroma of the lateral femoral cutaneous nerve
(LFCN). The condition can be differentiated from other neurologic disorders by
the typical exacerbating factors and the characteristic distribution of symptoms.
The disease process can be either spontaneous or iatrogenic. The spontaneous
form is usually mechanical in origin. The LFCN is subject to compression
throughout its entire course. Injuries most commonly occur as the nerve exits
the pelvis. The regional anatomy of the LFCN is highly varied and may account
for its susceptibility to local trauma. Relief of pain and paresthesias after injec-
tion of a local anesthetic agent is helpful in establishing the diagnosis. If no
improvement is found, proximal LFCN irritation should be sought. Idiopathic
meralgia paresthetica usually improves with nonoperative modalities, such as
removal of compressive agents, nonsteroidal anti-inflammatory drugs, and, if
necessary, local corticosteroid injections. If intractable pain persists despite
such measures, surgery can be considered, although whether neurolysis or tran-
section is the procedure of choice is still controversial. Iatrogenic meralgia
paresthetica has been found to occur after a number of orthopaedic procedures,
such as anterior iliac-crest bone-graft harvesting and anterior pelvic procedures.
Prone positioning for spine surgery has also been implicated. Variations in the
anatomy of the LFCN about the anterior superior iliac spine may place the

nerve at higher risk for damage. Although nonoperative management usually
results in satisfactory results, efforts should be made to avoid injury at the time
of surgery.
J Am Acad Orthop Surg 2001;9:336-344
Meralgia Paresthetica: Diagnosis and Treatment
Mark G. Grossman, MD, Stephen A. Ducey, MD,
Scott S. Nadler, DO, and Andrew S. Levy, MD
Mark G. Grossman, MD, et al
Vol 9, No 5, September/October 2001
337
iliac spine (ASIS). Distally, it enters
the anterior region of the thigh by
passing under, through, or above
the inguinal ligament. It is in this re-
gion that the nerve most commonly
becomes trapped or injured during
surgery (Fig. 1).
Most commonly, the LFCN passes
1 cm medial to the ASIS at the level
of the inguinal ligament, although
there is considerable anatomic varia-
tion.
5,6
It is important to understand
the regional anatomy and have a
working knowledge of the most
common variations that can precipi-
tate entrapment and increase sus-
ceptibility to injury during surgery.
Aszmann et al

7
delineated the fre-
quency of five variant locations of
the LFCN in 52 cadavers (Fig. 2). In
type A, the nerve overlies the iliac
crest (which occurred in 4% of the
cadavers in that study). In type B, it
is ensheathed by the inguinal liga-
ment (27%). In type C, the LFCN is
ensheathed by the tendinous origin
of the sartorius (23%). In type D, it
is deep to the inguinal ligament and
medial to the sartorius (26%). In type
E, it is positioned medially on top of
the iliopsoas (20%). Of note, 34 (65%)
of the cadavers had symmetrical dis-
tribution of nerves.
Other authors have noted multi-
ple branches of the LFCN crossing
the inguinal ligament. The intersec-
tion with the inguinal ligament can
be up to 2 cm lateral to, adjacent to,
or as much as 6 cm medial to the
ASIS.
6
Murata et al
8
characterized
the degree of risk of injury to por-
tions of the LFCN in relation to

bone-graft harvesting from the ante-
rior iliac crest. In their anatomic
study, 9.9% of the dissected nerves
lay in peril on top of or near the iliac
crest. The LFCN lies at a marked
angle to the inguinal ligament. This
angle can become more acute with
extension of the hip; therefore, ex-
treme positions should be avoided
intraoperatively.
Distal to the inguinal ligament,
the LFCN splits into anterior and
posterior divisions. Each penetrates
the fascia lata several centimeters
below the ASIS. The anterior branch
innervates the area from the anterior
thigh to the knee. The posterior
branch supplies the lateral thigh up
to the level of the greater trochanter.
Epidemiology
Although spontaneous meralgia
paresthetica occurs in all age groups,
9
it is most frequently noted in middle-
aged individuals. It may be more
prevalent in children than has been
reported in the literature.
10
The
spontaneous condition is generally

regarded as uncommon. Ecker and
Woltman
11
showed an incidence of 3
cases in 10,000 general clinic patients.
Jones
12
reported the diagnosis in
6.7% to 35% of patients referred for
leg discomfort. There is no consen-
sus in the literature about whether
there is a sex predominance.
Etiology
The etiology of this mononeuropa-
thy is highly variable. The disease
process may be categorized as either
spontaneous or iatrogenic. The spon-
taneous form occurs in the absence
of any prior surgical procedure that
may have injured the LFCN at some
point along its pathway, and can be
further categorized as either idio-
pathic or metabolic. The iatrogenic
form is a well-known complication
of many common orthopaedic proce-
dures. Both mechanical and meta-
bolic factors may be involved.
Mechanical Factors
The LFCN is subject to injury at
several sites along its course. Irri-

tation most often occurs at or near
the site where the LFCN pierces or
crosses the inguinal ligament. The
nerve is superficial at this point and
lies at an acute angle in hip exten-
sion. Stookey
13
noted that standing
aggravates symptoms and sitting
helps to relieve them. Predisposing
anatomic variations, such as types
A, B, and C in the classification of
Aszmann et al,
7
increase the likeli-
hood of compression.
External causes, such as the
wearing of seat belts,
11
girdles,
11
and tight trousers,
14
can result in
direct pressure on the LFCN. Obe-
sity, pregnancy, and other condi-
tions associated with increased ab-
dominal pressure may predispose
to entrapment.
6

Pelvic disease, such
as an intra-abdominal tumor, has
reportedly presented as meralgia
paresthetica.
15
The nerve may also
become trapped in a retroperitoneal
location or at the point where it pene-
trates the fascia lata. In rare in-
stances, a bone tumor in the iliac crest
near the ASIS can present as meralgia
paresthetica.
16
Metabolic Factors
Metabolic disorders such as dia-
betes mellitus, alcoholism, and lead
poisoning can cause an isolated
Figure 1 The anatomic course of the
LFCN. (Adapted with permission from
Mirovsky Y, Neuwirth M: Injuries to the
lateral femoral cutaneous nerve during
spine surgery. Spine 2000;25:1266-1269.)
LFCN
Likely point of
compression
Meralgia Paresthetica
Journal of the American Academy of Orthopaedic Surgeons
338
neuropathy of the LFCN. However,
the cause of metabolic neuropathy

has not been well defined.
In diabetes, there are two current
theories. One hypothesis involves
abnormalities in the metabolism of
pyruvate, sorbitol, and lipids. Spe-
cifically, the slowing of nerve con-
duction has been experimentally
linked to activation of the polyol
(sorbitol) pathway by glucose.
17
Sec-
ondary alterations in myo-inositol
and phosphoinositide metabolism
result in impairment of sodium-
potassium adenosine triphosphatase
activity, which leads to nerve dys-
function. The second hypothesis is
that in diabetes the nerve swells due
to decreased axoplasmic transport,
rendering it more susceptible to
compression.
18
Optimization of
blood glucose levels has not provided
relief for affected patients.
The treatment goal and therapeu-
tic approach for metabolic meralgia
paresthetica remain the same as
those for the mechanical form of the
disease. Similar treatment is also

employed for meralgia paresthetica
associated with inflammatory disor-
ders, such as lupus neuropathy.
18
Evaluation
The clinical presentation of meralgia
paresthetica includes pain, numb-
ness, and/or dysesthesia in the
region of the anterolateral thigh.
There is often a delay in diagnosis
in patients with these symptoms
and even failure to recognize the
entity. It is important for the clini-
cian to be familiar with the presen-
tation and treatment of this condi-
tion, because if undetected it may
lead to significant patient distress
and disability. Figure 3 is an algo-
rithm for the evaluation and treat-
ment of meralgia paresthetica.
History and Physical
Examination
Patients typically describe numb-
ness, tingling, pain, burning, and
decreased sensitivity to pain, touch,
and temperature in the distribution
of the LFCN. Hypersensitivity to
touch and dysesthesias may also be
reported. Palpating the area in
question usually aggravates symp-

toms. Many patients have tender-
ness over the lateral inguinal liga-
ment at the point where the nerve
crosses the ligament. The condition
is often exacerbated by hip exten-
sion during walking or getting into
and out of an automobile. An area
Figure 2 Five common variant locations of the LFCN as it exits the abdomen. In type A,
the LFCN overlies the iliac crest (frequency in the study by Aszmann et al
7
of 52 cadavers,
4%). In type B, the nerve is ensheathed by the inguinal ligament (27%). In type C, it is
ensheathed by the tendinous origin of the sartorius (23%). In type D, the nerve is deep to
the inguinal ligament and medial to the sartorius (26%). In type E, it is positioned medial-
ly on top of the iliopsoas (20%). (Adapted with permission from Aszmann OC, Dellon ES,
Dellon AL: Anatomical course of the lateral femoral cutaneous nerve and its susceptibility
to compression and injury. Plast Reconstr Surg 1997;100:600-604.)
Type A Type B Type C
Type D Type E
Mark G. Grossman, MD, et al
Vol 9, No 5, September/October 2001
339
of hair loss may be present on the
thigh secondary to repetitive rub-
bing of the region by the patient.
This massaging is a common at-
tempt to relieve symptoms and is an
important diagnostic clue.
The clinical presentation is usu-
ally unilateral; however, 20% of

patients present with bilateral com-
plaints.
11
Other neurologic, gastro-
intestinal, and urogenital symptoms
are not part of the process; their
presence should suggest that the leg
symptoms are due to a condition
other than meralgia paresthetica.
The constellation of signs and
symptoms that has been described
usually enables the physician to
make a diagnosis based on the histo-
ry and physical examination find-
ings. A Tinel’s sign is frequently pres-
ent 1 cm medial and inferior to the
ASIS, but is dependent on anatomic
variation. The nerve may be palpa-
ble in thin patients, which may cause
irritation. Rapid relief of symptoms
with a local anesthetic nerve block
can confirm the diagnosis.
Electrodiagnostic Testing
When the history and physical
examination are nonconfirmatory,
electrodiagnostic testing may be
effective in establishing the diagno-
sis. Two techniques for evaluating
nerve conduction can be used. The
first method involves stimulating

the LFCN as it exits the pelvis near
the ASIS and recording potentials
distally. The second technique in-
volves stimulating distally along the
course of the nerve and recording
proximally in the region of the ASIS.
Measurements on the unaffected
side should always be recorded, as
these responses are typically of
small amplitude.
19
Somatosensory evoked potentials
(SSEPs) can also be utilized with
segmental or dermatomal tech-
niques. An abnormal latency or a
side-to-side decrement greater than
50% is considered abnormal.
20,21
Wiezer et al
22
found that SSEPs
were useful in determining whether
meralgia paresthetica was caused
by an injury in a region proximal to
the ASIS. However, on comparing
the results of nerve conduction
studies with the SSEP findings in 30
patients with clinical evidence of
unilateral meralgia paresthetica,
Seror

23
found that nerve conduction
studies were more accurate.
Differential Diagnosis
Any patient with a motor deficit,
reflex changes, or sensory deficits
not specific to the LFCN should be
completely evaluated. Other causes
of anterolateral thigh pain must be
considered. A plain radiograph
should be obtained to assess the pel-
vic architecture as well as to elimi-
nate pelvic tumors and osteoarthritis
Positive Negative
Condition resolved
No further treatment
Condition unresolved
Condition
resolved
Condition
unresolved
No further
treatment
Surgical
exploration
Evaluate further for underlying
condition (e.g., neuropathy,
radiculopathy, proximal
entrapment)
Initial treatment with NSAIDs,

protection, avoidance of compression
Pharmacologic intervention
Local steroid injection
History that suggests idiopathic meralgia paresthetica:
• Location of sensory alteration in anterolateral thigh
• Pain, numbness, dull ache, itching, tingling
• History of trauma to region
• History of diabetes, alcoholism, or lead poisoning
• No previous surgery that might have affected the LFCN
Diagnostic regimen:
• Diagnostic nerve block
• Electrodiagnostic testing
• Somatosensory evoked potentials
Physical examination findings that suggest
idiopathic meralgia paresthetica:
• Sensory changes (hypesthesia, hyperesthesia,
dysesthesia present over anterolateral thigh)
• Signs/symptoms exacerbated by hip extension
Figure 3 Algorithm for the evaluation and treatment of idiopathic meralgia paresthetica.
Meralgia Paresthetica
Journal of the American Academy of Orthopaedic Surgeons
340
of the hip as potential etiologic
factors.
Differentiation of inguinal re-
gional entrapment of the LFCN due
to upper lumbar nerve compression
or intra-abdominal compression is
more challenging. In such cases,
local block would not be expected to

relieve the symptoms. Any con-
comitant gastrointestinal or urogen-
ital symptoms should immediately
raise suspicion of a pelvic mass.
Ultrasound, computed tomogra-
phy, or magnetic resonance imaging
can be used to assess the retroperi-
toneal region. The entity most com-
monly confused with meralgia
paresthetica is lumbar disk disease.
Meralgia paresthetica is purely sen-
sory in nature and does not follow
distinct dermatomal distributions,
in contrast to disk disease, in which
there may be motor or reflex def-
icits. In the patient with meralgia
paresthetica, there should be no sci-
atic notch tenderness or a positive
response to the straight-leg-raising
test. Symptoms are usually relieved
with hip flexion. Both clinical exam-
ination and electromyography can
usually differentiate the entities.
However, magnetic resonance imag-
ing may be necessary to establish the
diagnosis. Somatosensory evoked
potentials have been used success-
fully by several authors to support a
diagnosis of meralgia paresthetica if
further clarification is needed.

24
Nonoperative Management
Nonoperative treatment of patients
with focal compression of the LFCN
should be directed at correcting the
underlying disorder. A history of
recent weight gain, tightness when
wearing trousers, or recent trauma
should be sought. The patient should
be warned to avoid compression, and
application of protective padding
over the region should be considered.
Nonsteroidal anti-inflammatory
drugs are the mainstay of treatment
to alleviate inflammation, which may
cause intrinsic compression. The use
of tricyclic antidepressants, anticon-
vulsants, and antiarrhythmic agents
may be initiated to treat the effects of
neuropathic pain.
25
Topical agents,
such as capsaicin and lidocaine-
prilocaine cream, can also be tried to
decrease surface hypersensitivity.
26
Meralgia paresthetica in pregnancy
usually resolves after delivery.
5
Local injection of xylocaine with a

corticosteroid may be beneficial to
decrease local inflammation. This
should be performed 1 cm medial to
the ASIS or in the region of maximal
tenderness. Repeat injections may be
required, as determined by the clini-
cal course. Local infiltration resulted
in complete relief for 32 (74%) of 43
patients in one study with a follow-
up interval of 1 year.
27
Edelson and
Stevens,
10
however, found a lack of
response to steroids in children.
Overall, nonoperative treatment
has yielded excellent results. How-
ever, most clinical series have em-
ployed numerous treatment methods;
therefore, the efficacy of individual
modalities is unclear. In a review of
29 patients, Ecker and Woltman
11
reported that approximately two
thirds showed improvement with
nonoperative treatment at the 2-
year follow-up evaluation. How-
ever, no details were offered regard-
ing the condition of those for whom

nonoperative therapy was a failure.
Williams and Trzil
6
demonstrated
relief of symptoms with nonopera-
tive care in more than 91% of 277
patients with meralgia paresthetica.
Bollinger
28
reported a 25% recovery
rate in his series of 158 patients.
Surgical Intervention
Nonoperative treatment alone will
reduce the severity of most patients’
symptoms to an acceptable level.
Only when the complaints become
intractable and disabling should
surgery become an option. Surgical
procedures for meralgia paresthetica
date back to 1885. Three basic sur-
gical techniques have evolved for
this disorder: neurolysis of only the
constricting tissue, neurolysis and
transposition of the LFCN, and tran-
section with excision of a portion of
the LFCN.
Neurolysis
Macnicol and Thompson
29
re-

ported on 25 patients with refractory
meralgia paresthetica. Exploration
and decompression of the LFCN 18
months after the onset of pain was
successful in 11 (44%) of these pa-
tients at an average follow-up inter-
val of 5.5 years. On the basis of their
results, the authors recommended
surgery for patients with symptoms
with a duration of less than 1 year as
well as clearly defined sensory loss.
Nahabedian and Dellon
18
noted
complete relief of symptoms in 18
of 23 patients and partial relief in 4
others after surgical decompression
of the nerve. Edelson and Stevens
10
reported the results of treatment of
21 lesions in 13 children. After oper-
ative decompression, there was com-
plete relief of pain from 14 lesions,
occasional pain but no disability
from 5 lesions, and persistent pain
only with sports activities with 2
lesions.
Neurolysis and Transposition
Keegan and Holyoke
4

described
two cases in which LFCN release
and medial transposition provided
good results. Aldrich and van den
Heever
30
described a suprainguinal
ligament approach for release and
transposition. In both studies, per-
formance of this procedure was con-
tingent on the nerve appearing as a
single trunk at the ASIS. No larger
series in which this particular tech-
nique was used have been reported.
Transection
Williams and Trzil
6
reported the
data on 24 patients with meralgia
paresthetica that was unrelieved by
Mark G. Grossman, MD, et al
Vol 9, No 5, September/October 2001
341
nonoperative measures. Sectioning
of the LFCN successfully relieved
symptoms in 23 of the 24 patients.
Although sectioning of the nerve
results in permanent anesthesia in
the anterolateral thigh, there were
no other serious sequelae.

Transection Versus Neurolysis
In 1995, van Eerten et al
31
com-
pared the results of transection and
neurolysis in 21 patients after failure
of nonoperative treatment. Transec-
tion was performed in 11 patients
and neurolysis in 10 patients. The
average follow-up interval was 74
months. Complete relief of symp-
toms occurred in 9 patients who
underwent transection, compared
with 3 patients in whom neurolysis
was used. Therefore, the authors
recommended transection as the
procedure of choice.
Ivins
32
performed neurolysis in
four of eight operative cases of me-
ralgia paresthetica. All four patients
had consistent immediate relief,
but the symptoms recurred 2 to 24
months later. All four subsequently
underwent resection of the LFCN
and had no recurrence. The other
four underwent initial transection
and had persistent relief at long-
term follow-up (3 to 6 years).

Whether the preferred surgical
management is neurolysis or tran-
section remains controversial. Pro-
ponents of neurolysis assert that the
nerve should be decompressed
from just proximal to the pelvic
brim to as far distally as possible.
They believe this will provide ade-
quate decompression and successful
surgery without the disadvantage of
creating permanent anterolateral
anesthesia. Some surgeons have
reported unpleasant hyperesthesias
with resection, whereas others have
reported dysesthesias after neu-
rolysis but not after transection.
31
Symptoms in an intact nerve may
be due to an LFCN neuroma, which
neurolysis cannot ameliorate. Re-
section should, therefore, be cura-
tive, providing more predictable
relief but at the expense of the sen-
sory innervation.
The initial step should be to per-
form neurolysis with decompres-
sion. Resection is contemplated
only after failure of neurolysis. In
certain situations, transection may
be the treatment of choice if neurol-

ysis and/or transposition is not
feasible. Transection may be ap-
propriate if the LFCN has been
irreparably damaged by pressure,
if there are multiple branches of the
LFCN exiting the pelvis, if the
LFCN crosses the iliac crest, or if an
adult patient has had symptoms
for more than 1 year.
Surgical Technique
As the entire nerve should be ex-
plored, an adequate incision must
be made to allow for the anatomic
variations that have been reported.
With the patient under general
anesthesia, a 3- to 5-cm oblique or S-
shaped incision is made 2 cm distal
to the area of tenderness at the pre-
sumed pelvic brim exit of the LFCN.
Exposure is carried down to the
level of the LFCN. Once identified,
the nerve is examined for pathologic
changes (Fig. 4). The nerve is then
released toward the thigh and into
the retroperitoneum, with excision
of all overlying and underlying fas-
cia, including the compressive por-
tion of the inguinal ligament.
The nerve must be properly ex-
posed for transection. The nerve is

then pulled distally and sectioned
so that the released proximal end
falls back in the pelvis, thereby
avoiding neuroma formation. A
nerve segment of at least 4 cm must
be resected, including any portion
with obvious pathologic changes.
Iatrogenic Meralgia
Paresthetica
Meralgia paresthetica has been re-
ported after several types of surgical
procedures in the region of the ASIS.
The surgical approaches may either
directly injure the nerve or endanger
the nerve with local scarring.
33
These procedures include acetabular
fracture surgery,
34,35
pelvic osteoto-
mies,
36
and bone-graft harvesting
from the iliac crest.
33,37-39
It has also
been reported after several nonor-
thopaedic interventions, such as
bariatric surgery
40

and laparoscopic
hernia repair.
41
Symptoms of antero-
lateral dysesthesia after surgery in
the region of the hip or pelvis should
suggest the presence of meralgia
paresthetica.
Nonoperative modalities, in-
cluding the use of nonsteroidal anti-
inflammatory drugs, looser clothing,
and steroid injections, are impor-
tant initial measures. Resolution of
symptoms generally occurs within 3
months. However, persistent symp-
toms may necessitate surgical inter-
vention.
There has not yet been a well-
controlled study comparing the use
of neurolysis and transection in the
treatment of postsurgical meralgia
paresthetica. However, most authors
of larger series recommend transec-
tion because of the potential for neu-
roma formation.
Figure 4 Exploration of the LFCN reveals
entrapment of the nerve. White arrow
indicates inguinal ligament; arrowhead,
LFCN; black arrow, point of entrapment
between two slips of inguinal ligament.

Meralgia Paresthetica
Journal of the American Academy of Orthopaedic Surgeons
342
Bone-Graft Harvesting From
the Anterior Iliac Crest
Injury to the LFCN has been re-
ported in as many as 10% of cases in
series in which bone was harvested
from the anterior iliac crest.
33,37-39
Kurz et al
39
described three mecha-
nisms for nerve injury in this setting:
neurotmesis as the nerve crosses the
anterior iliac crest, neurapraxia due
to retraction of the iliacus during
exposure of the ilium, and crush
injury to the outer table of the iliac
crest secondary to excessive strip-
ping. One recommendation is to
keep incisions 2 cm lateral to the
ASIS.
39
The LFCN is lateral to the
ASIS when it crosses the iliac crest in
as many as 10% of cases.
5-8
When taking a graft from the
outer table of the iliac crest, it is

important to avoid penetration of
the inner table, so as to prevent in-
jury as the LFCN crosses the iliacus
muscle. Careful retraction and dis-
section of the inner table will also
limit injury to the LFCN. If the
LFCN is found to be injured, the
nerve should be severed and allowed
to retract into the pelvic region. This
will decrease the incidence of neu-
roma formation. Overall, meticu-
lous hemostasis and dissection will
minimize hematoma and scar for-
mation. Use of a drain may be ben-
eficial in preventing postoperative
hematoma formation.
Newer coring techniques for
bone-graft harvesting from the iliac
crest have also been implicated in
LFCN damage.
42
Although there
are many potential advantages to
the coring technique for graft har-
vesting, one must understand that
with certain anatomic variants the
LFCN is still in danger. Recom-
mendations to avoid injury include
making a 1-cm incision at least 5 cm
but no more than 8 cm posterior to

the ASIS. Retractors should be
placed after careful blunt dissection
to the crest and should remain fixed
during coring to minimize the risk
of neurotmesis.
Spine Procedures
Spine surgery carries the risk of
LFCN injury during bone-graft har-
vesting from the anterior iliac crest,
prone positioning, and retroperito-
neal approaches. Mirovsky and
Neuwirth
43
found a 20% complica-
tion rate in 105 patients who under-
went a spine procedure. Each subset
of spine procedures or approaches
was examined separately. Compres-
sion was implicated as the cause of
LFCN damage when a Hall-Relton
frame was used for posterior spinal
fusions. All the bilateral injuries
were found in this group. Bone-
graft harvesting from the anterior
iliac crest was also implicated in the
anterior cervical fusion group. Two
patients who did not recover func-
tion after 1 year were in this group.
It may be assumed that the nerve
was transected during the surgical

approach. Retraction of the psoas
during retroperitoneal dissection
was also found to be a cause of
LFCN neurapraxia, as the LFCN
travels just lateral to the muscle in
the pelvic region.
Because of the small numbers of
patients in the subgroups in that
study, it was not possible to mea-
sure the prevalence of LFCN injury
in each. However, 89% of all injured
nerves had recovered by 3 months.
Avoiding excessive retraction about
the LFCN and using adequate pad-
ding during prone positioning may
decrease the incidence of postopera-
tive meralgia paresthetica. It is im-
portant that patients be informed
about the potential occurrence of this
complication.
Use of Ilioinguinal and
Iliofemoral Approaches
The ilioinguinal approach to the
acetabulum risks injury to the LFCN.
The nerve may be injured due to
excessive retraction, postoperative
scar or hematoma formation, or di-
rect injury. Hospodar et al
35
per-

formed cadaver dissections utilizing
the ilioinguinal approach to deter-
mine its relationship to the LFCN.
At some points, the nerve was as
much as 40 mm away from the ASIS.
Therefore, if the LFCN is not found
near the ASIS, careful medial dissec-
tion may be necessary to locate the
nerve.
De Ridder et al
34
performed a
two-part study: an anatomic study
and a clinical correlation. An ilioin-
guinal approach was used on 200
cadavers. The LFCN was found to
be normal in position in 149 (74%)
and abnormal in 51 (26%). A clini-
cal retrospective analysis found 82
patients with postoperative LFCN
sensory changes after use of an
ilioinguinal approach. Eleven had
persistent symptoms after 1 year,
and 5 went on to require surgical in-
tervention. In a second group of 40
patients treated after the first group,
a perioperative protocol was insti-
tuted to diminish the risk of meral-
gia paresthetica. The LFCN was
identified and neurolysis was per-

formed in 33 patients. The remain-
ing 7 patients underwent transection
of the nerve because of an intraoper-
ative lesion. No complaints were
noted at 1 year. The transection
group had a decrease in the area of
insensate distribution. Overall, the
incidence of decreased sensation in
their series was 35%, and painful
dysesthesias occurred in 5% of their
patients.
Recommendations regarding
acetabular approaches include
flexing the hip to minimize LFCN
tension and trimming the anterior
iliac crest before wound closure to
avoid excessive retraction of the
nerve. Knowledge of the anatomic
variations should lessen direct
injury. If intraoperative injury is
discovered, transection may be
necessary to avoid neuroma for-
mation. Most symptoms subside
by 3 to 6 months after surgery.
The patient should always be
informed of the risk of potential
LFCN injury when discussing
these acetabular approaches.
Mark G. Grossman, MD, et al
Vol 9, No 5, September/October 2001

343
Summary
Meralgia paresthetica is a mono-
neuropathy of the LFCN. The con-
dition may be categorized as either
spontaneous or iatrogenic. The
spontaneous form may be further
categorized as either mechanical or
metabolic in origin. A thorough
clinical history and physical exami-
nation will often be sufficient for
accurate diagnosis of the disorder.
Nonoperative treatment is usually
successful. However, a small num-
ber of patients will need operative
intervention. Most iatrogenic cases
of meralgia paresthetica abate with
time. It is essential to clearly in-
form patients about the risk of
LFCN injury before surgery about
the ASIS. Meticulous intraopera-
tive technique may decrease the
incidence of the disorder after
pelvic surgery.
References
1. Schneck JM: Sigmund Freud, Josef
Breuer, and Freud’s self-observations
on meralgia paresthetica. N Y State J
Med 1983;83:968-969.
2. Sunderland S: Nerves and Nerve Injuries.

Edinburgh: E & S Livingstone, 1968.
3. Huber GC (ed): Human Anatomy: Includ-
ing Structure and Development and Prac-
tical Considerations, 9th ed. Philadel-
phia: JB Lippincott, 1930, pp 2104-2106.
4. Keegan JJ, Holyoke EA: Meralgia
paresthetica: An anatomical and surgi-
cal study. J Neurosurg 1962;19:341-345.
5. Ghent WR: Further studies on meral-
gia paresthetica. Can Med Assoc J 1961;
85:871-872.
6. Williams PH, Trzil KP: Management
of meralgia paresthetica. J Neurosurg
1991;74:76-80.
7. Aszmann OC, Dellon ES, Dellon AL:
Anatomical course of the lateral fem-
oral cutaneous nerve and its suscepti-
bility to compression and injury. Plast
Reconstr Surg 1997;100:600-604.
8. Murata Y, Takahashi K, Yamagata M,
Shimada Y, Moriya H: The anatomy
of the lateral femoral cutaneous nerve,
with special reference to the harvest-
ing of iliac bone graft. J Bone Joint Surg
Am 2000;82:746-747.
9. Massey EW, Pellock JM: Meralgia
paraesthetica in a child. J Pediatr 1978;
93:325-326.
10. Edelson R, Stevens P: Meralgia pares-
thetica in children. J Bone Joint Surg

Am 1994;76:993-999.
11. Ecker AD, Woltman HW: Meralgia
paresthetica: A report of one hundred
and fifty cases. JAMA 1938;110:1650-1652.
12. Jones RK: Meralgia paresthetica as a
cause of leg discomfort. Can Med
Assoc J 1974;111:541-542.
13. Stookey B: Meralgia paresthetica: Eti-
ology and surgical treatment. JAMA
1928;90:1705-1707.
14. Boyce JR: Meralgia paresthetica and
tight trousers [letter]. JAMA 1984;
251:1553.
15. Suber DA, Massey EW: Pelvic mass
presenting as meralgia paresthetica.
Obstet Gynecol 1979;53:257-258.
16. Tharion G, Bhattacharji S: Malignant
secondary deposit in the iliac crest mas-
querading as meralgia paresthetica.
Arch Phys Med Rehabil 1997;78:1010-1011.
17. Kim J, Kyriazi H, Greene DA: Normal-
ization of Na(+)-K(+)-ATPase activity
in isolated membrane fraction from
sciatic nerves of streptozocin-induced
diabetic rats by dietary myo-inositol
supplementation in vivo or protein
kinase C agonists in vitro. Diabetes
1991;40:558-567.
18. Nahabedian MY, Dellon AL: Meralgia
paresthetica: Etiology, diagnosis, and

outcome of surgical decompression.
Ann Plast Surg 1995;35:590-594.
19. Dumitru D: Electrodiagnostic Medicine.
Philadelphia: Hanley & Belfus, 1995,
p 672.
20. Lagueny A, Deliac MM, Deliac P,
Durandeau A: Diagnostic and prog-
nostic value of electrophysiologic tests
in meralgia paresthetica. Muscle Nerve
1991;14:51-56.
21. Sener HO, Ulkatan S, Selcuki D: Effect
of thigh flexion on somatosensory
evoked potentials in meralgia pares-
thetica. Acta Neurol Belg 1999;99:194-197.
22. Wiezer MJ, Franssen H, Rinkel GJ,
Wokke JH: Meralgia paresthetica:
Differential diagnosis and follow-up.
Muscle Nerve 1996;19:522-524.
23. Seror P: Lateral femoral cutaneous
nerve conduction vs somatosensory
evoked potentials for electrodiagnosis
of meralgia paresthetica. Am J Phys Med
Rehabil 1999;78:313-316.
24. Po HL, Mei SN: Meralgia paresthetica:
The diagnostic value of somatosensory
evoked potentials. Arch Phys Med
Rehabil 1992;73:70-72.
25. Massey EW: Sensory mononeuropa-
thies. Semin Neurol 1998;18:177-183.
26. Puig L, Alegre M, de Moragas JM:

Treatment of meralgia paraesthetica
with topical capsaicin [letter]. Derma-
tology 1995;191:73-74.
27. Prabhakar Y, Bahadur RA, Mohanty
PR, Sharma S: Meralgia paraesthetica.
J Indian Med Assoc 1989;87:140-141.
28. Bollinger A: Meralgia paraesthetica:
Clinical picture and pathogenesis
based on 158 personal cases [German].
Schweiz Arch Neurol Psychiatry 1961;
87:58-102.
29. Macnicol MF, Thompson WJ: Idio-
pathic meralgia paresthetica. Clin
Orthop 1990;254:270-274.
30. Aldrich EF, van den Heever CM:
Suprainguinal ligament approach for
surgical treatment of meralgia pares-
thetica: Technical note. J Neurosurg
1989;70:492-494.
31. van Eerten PV, Polder TW, Broere
CAJ: Operative treatment of meralgia
paresthetica: Transection versus neu-
rolysis. Neurosurgery 1995;37:63-65.
32. Ivins GK: Meralgia paresthetica, the
elusive diagnosis: Clinical experience
with 14 adult patients. Ann Surg 2000;
232:281-286.
33. Weikel AM, Habal MB: Meralgia
paresthetica: A complication of iliac
bone procurement. Plast Reconstr Surg

1977;60:572-574.
34. de Ridder VA, de Lange S, Popta JV:
Anatomical variations of the lateral
femoral cutaneous nerve and the con-
sequences for surgery. J Orthop
Trauma 1999;13:207-211.
35. Hospodar PP, Ashman ES, Traub JA:
Anatomic study of the lateral femoral
cutaneous nerve with respect to the
ilioinguinal surgical dissection. J
Orthop Trauma 1999;13:17-19.
36. Grossbard GD: Hip pain during ado-
lescence after Perthes’ disease. J Bone
Joint Surg Br 1981;63:572-574.
37. Massey EW: Meralgia paresthetica
secondary to trauma of bone graft. J
Trauma 1980;20:342-343.
38. Banwart JC, Asher MA, Hassanein RS:
Iliac crest bone graft harvest donor site
morbidity: A statistical evaluation.
Spine 1995;20:1055-1060.
39. Kurz LT, Garfin SR, Booth RE: Har-
Meralgia Paresthetica
Journal of the American Academy of Orthopaedic Surgeons
344
vesting autogenous iliac bone grafts: A
review of complications and tech-
niques. Spine 1989;14:1324-1331.
40. Macgregor AM, Thoburn EK: Meralgia
paresthetica following bariatric sur-

gery. Obes Surg 1999;9:364-368.
41. Dibenedetto LM, Lei Q, Gilroy AM,
Hermey DC, Marks SC Jr, Page DW:
Variations in the inferior pelvic path-
way of the lateral femoral cutaneous
nerve: Implications for laparoscopic
hernia repair. Clin Anat 1996;9:232-236.
42. van den Broecke DG, Schuurman AH,
Borg ED, Kon M: Neurotmesis of the
lateral femoral cutaneous nerve when
coring for iliac crest bone grafts. Plast
Reconstr Surg 1998;102:1163-1166.
43. Mirovsky Y, Neuwirth M: Injuries to
the lateral femoral cutaneous nerve
during spine surgery. Spine 2000;25:
1266-1269.