Download Superior Cluneal Nerve Entrapment Eight Years after Decubitus

Blackwell Science, LtdOxford, UKPPRPain Practice1530-70852005 World Institute of Pain54364366Case ReportSuperior Cluneal Nerve EntrapmentAKBAS Et al.
CLINICAL REPORT
Superior Cluneal Nerve
Entrapment Eight Years after
Decubitus Surgery
Mert Akbas, MD; Arif Yegin, MD; Bilge Karsli, MD
Department of Anesthesiology, Division of Algology, Akdeniz University Medical Faculty,
Antalya, Turkey
Abstract
Background and Objective: Superior cluneal nerve (SCN)
entrapment is one of the infrequent etiologies of low back
pain (LBP), which is rarely diagnosed. Few clinical reports
have been published in the literature. We present a case of
severe LBP radiating to the ipsilateral buttock after decubitus
surgery.
Case Report: A 62-year-old man weighing 85 kg presented
to the algology department, suffering from severe LBP of
6 months duration. The pain was in the right iliac crest region
with radiation to the ipsilateral buttock. After admission, his
history was taken, physical examination was performed, and
further evaluations were made. He was suspected of having
facet and right sacroiliac joint pain. Two tender points were
found 6.5 and 7.5 cm to the right of the midline over the iliac
crest. Local anesthetic with corticosteroid was injected at the
tender points over the right iliac crest. Five minutes after the
injection, the pain dissipated.
Conclusion: SCN entrapment should be considered in
patients who suffer from LBP radiating to the iliac crest and
buttock after other causes of LBP have been excluded. Key Words: cluneal nerve, decubitus surgery, diagnosis
Address correspondence and reprint requests to: Mert Akbas, MD,
Department of Anesthesiology, Akdeniz University Medical Faculty, 07070
Antalya, Turkey. Tel: +90-242-2274343-55375; Fax: +90-242-2278836; Email: [email protected].
© 2005 World Institute of Pain, 1530-7085/05/$15.00
Pain Practice, Volume 5, Issue 4, 2005 364–366
INTRODUCTION
Evaluation of soft tissue often reveals nerve entrapment
distal to the spine. When this occurs, generally it is
thought to be referred pain, not the direct cause of the
patient’s pain. Complaints of pain over the medial portion of the iliac crest and in the gluteal or lumbosacral
area tend to be diagnosed as a facet syndrome, a lower
lumbar disc problem, or an iliolumbar syndrome. Superior cluneal nerve (SCN) entrapment is one of the less
common etiologies, which is rarely diagnosed. Few clinical reports have been published.
Here we present a case of cluneal nerve entrapment
resulting in severe low back pain (LBP) radiating to the
ipsilateral buttock after decubitus surgery.
CASE REPORT
A 62-year-old man weighing 85 kg presented with
unremitting LBP. He provided a history of having
undergone coronary artery bypass surgery 8 years previously. His postoperative course was complicated, and
he remained in the intensive care unit (ICU) for
2 months because of respiratory insufficiency. During
his ICU stay, he developed a decubitus ulcer in the right
sacro-gluteal region. He subsequently underwent decubitus ulcer surgery after discharge from the ICU. Two
weeks after surgery, he was discharged from hospital
without any further complication. He presented to the
algology department 8 years later suffering from severe
LBP of 6 months duration, localized to the right iliac
Superior Cluneal Nerve Entrapment • 365
crest with radiation to the ipsilateral buttock. He was
previously treated with physical therapy and medications, including nonsteroidal anti-inflammatory drugs,
without relief.
After admission to the algology department, a history
and physical examination were performed, and radiologic, orthopedic, and neurological evaluations were
undertaken. On examination, straight-leg-raising tests
were negative bilaterally. Both forward and backward
bending were painful and limited. Pain worsened with
spine rotation and crouching. Palpation over the sacroiliac joints, spinous processes, and interspinous ligaments was less painful. The patient was suspected of
having facet and right sacroiliac joint pain. Tender
points were found 6.5 and 7.5 cm to the right of the
midline over the iliac crest. The tender points, upon
tactile stimulation, elicited pain radiating from the low
back down to the buttock, consistent with the distribution of SCN branches. His pain on a visual analog scale
was 8 to 9 out of 10.
Radiological examination included anteroposterior,
lateral, and bilateral oblique radiographs of the lumbosacral spine; anteroposterior suprapubic radiographs
of the pelvis and the sacroiliac joints; and magnetic
resonance imaging (MRI) of the lumbosacral spine.
These studies revealed no pathologic findings. Orthopedic and neurosurgical consultations also revealed no
abnormalities.
A combination of local anesthetic and corticosteroid
was injected into the tender points over the right iliac
crest. This was effective in reducing the pain within
5 minutes. The patient was discharged after a 1-hour
observation with a complete pain relief and no need for
additional medication. He was evaluated 4 days later at
which time he remained pain-free. Seven days after the
first procedure, the pain returned, and he underwent a
second injection. The second procedure was also
effective in reducing the pain. Over the next 2 weeks,
his pain decreased gradually. During his final visit, at
3 months, he had no pain complaints.
TECHNIQUE
The patient was taken to the operating room and positioned prone under sterile surgical conditions. The
right posterior iliac crest was marked at 6.5, 7.5, and
8.5 cm for the approximate location of the SCN under
fluoroscopic guidance. Tender points at 6.5 and 7.5 cm
lateral to midline (L4) at the level of the right iliac
crest over the distribution of SCN, were each infiltrated with 3 mL of 0.2% ropivacaine with 20 mg tri-
amcinolone. Complete pain relief was obtained after
the procedure. During the second procedure infiltrations with 2 mL of 0.2% ropivacaine with 10 mg
triamcinolone were used.
DISCUSSION
Neural entrapment involves a mechanical irritation of a
specific peripheral nerve when it becomes locally compressed at a given anatomical site.1 An extensive literature search revealed relatively few reports describing
SCN entrapment and therapy.1–6
Common entrapment neuropathies include intercostal, median (carpal tunnel), lateral femoral cutaneous,
and ulnar and peroneal nerves.7 Lu et al.8 initially
described the anatomic relationship of the SCN to the
posterior iliac crest and thoracolumbar fascia. They dissected 15 cadavers and found that the medial branch of
the SCN is confined within a tunnel created by the
thoracolumbar fascia and the superior rim of the iliac
crest as the nerve passes over the iliac crest. The location
is 7 to 8 cm lateral to the midline on the iliac crest, just
lateral and superior to the posterior superior iliac spine.
If this pain location was due to a facet syndrome, the
facet affecting the superior cluneal nerves would be at
the level of T12, L1, or L2, whose nerves come out
through the lumbosacral fascia at the lateral origin of
the sacrospinalis muscles and cross over the dorsal part
of the posterior iliac crest.9 Pressure over the involved
facet joint often evokes pain in facet syndrome, and the
pain would typically be relieved if the facet joint was
injected. The tender point involved corresponded to the
insertion of the iliolumbar ligament, but the insertion of
the iliolumbar ligament is on the anterior aspect of the
iliac crest and cannot be palpated.10 However, injection
of a trigger point in this area might offer relief because
of its effect on the adjacent cluneal nerve.
All branches of the SCN extend from a perforating
point on the fascia to their cutaneous innervation on the
buttock. In this case, the SCNs were probably entrapped
between the rigid fibers of the thoracolumbar fascia and
the iliac crest.
Nerve compression lesions usually result from the
combination of several types of trauma on the nerve,
including traction, friction, and repetitive compression,
which lead to local edema in the surrounding tissue and
interference with the normal sliding movement of the
nerve. In SCN entrapment neuropathy, the anatomic
and functional bases for the development of the lesions
are a rigid fascial edge and stretch of the gluteus maximus and skin over a large area by flexion of the hip
366 • akbas et al.
joint, especially during activity. The nerve becomes
subjected to stretching forces that cause tissue edema,
irritation, inflammatory cell infiltration, and scarring,
which leads to the subsequent entrapment.5
Entrapment neuropathies are usually treated conservatively, unless the symptoms become severe and weakness or atrophy develops.7 Diagnostic blocks with local
anesthetics can be used and, if successful in relieving the
pain, the patient may be treated by injection of local
anesthetics with steroid, surgical release, cryotherapy, or
phenol injection.7 In this case, we performed 2 SCN
injections with local anesthetic and steroid. The patient
remained pain-free at 3 months following treatment.
In summary, SCN entrapment should be considered
for individuals with LBP radiating to the iliac crest and
buttock when other causes of LBP have been excluded.
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