Surgical correction of proximal femoral nerve entrapment

ELSEVIER

Peripheral Nerve

SURGICAL FEMORAL

CORRECTION OF PROXIMAL NERVE ENTRAPMENT

Stephen E. Natelson, M.D., F.A.C.S. Fort Sanders Neurosurgical Clinic, Knoxville,

Natelson SE. Surgical correction of proximal femoral nerve entrapment. Surg Neurol 1997;48:326-9. BACKGROUND

Femoral nerve palsy is usually a result of trauma. Isolated

femoral nerve palsy without external trauma is restricted to occasional case reports in various circumstances. CASE

DESCRIPTION

Three cases of nontraumatic femoral nerve palsy are reported who presented with pain and weakness.Symp toms were relieved by transection of the iliopectineal arch. This is believed to be a newly described syndrome. An additional case of femoral nerve entrapment following vaginal hysterectomy is described. This case presented only as a pain syndrome. CONCLUSIONS

There is a syndrome of femoral nerve entrapment at the iliopectineal arch that can be easily relieved by sectioning of this arch, analogous to carpal tunnel syndrome. Several casesof femoral nerve palsy previously reported may be examples of this syndrome. 0 1997 by Elsevier

Science Inc. KEY WORDS

Femoral nerve, iliopectineal arch.

T

he author has encountered several cases of a previously undescribed syndrome of proximal femoral nerve entrapment. Most commonly, the neurosurgeon is called on to treat a femoral nerve injured by external trauma [8,9,12]. Occasionally, the femoral nerve is injured during the course of total hip replacement [ 13,19,21] or transfemoral angiography, including delayed palsy from hematoma

W31. Reports have appeared concerning femoral nerve palsy associated with chronic anticoagulation and retroperitoneal hematoma [ 2,6,7,16,24]. There are isolated reports of femoral nerve palsy occurring in these circumstances: (1) after vaginal delivery [ 151, (2) after vaginal hysterectomy or similar gynecoAddress reprint requests to: Stephen E. Natelson, M.D., F.A.C.S., Fort Sanders Neurosurgical Clinic, 2001 Laurel Avenue, Suite 103, Knoxville, TN 37916. Received August 15, 1996; accepted February 13, 1997. 00903019/97/$17.00 PII s009(r3019(97)00171-7

Tennessee

logic procedure in the lithotomy position [4,22], (3) femoral nerve palsy in certain athletes such as bicyclists [l] and dancers [ 11,181, (4) femoral nerve palsy after a drunken stupor that was dubbed “hanging leg syndrome” [ 171, and (5) femoral nerve palsy in rheumatoid disease [lo]. Some of these cases may be related to the syndrome discussed below [3,14,20].

CASESTUDIES CASE 1 This 67-year-old physician, Chairman of Pathology, who is unusually active in athletic activities including handball, swimming, and hiking in the mountains developed pain in the hip radiating into the right leg in 1991, He reported weakness of the proximal right leg that was difficult to document because he was exceptionally strong and fit. Numerous studies were done including computed tomography (CT) myelogram, magnetic resonance imaging (MRl) of the lumbar spine and retroperitoneal area, and electromyogram (EMG). Testing seemed to indicate an L2 radiculopathy and it was reported by neuroradiologists that the patient had foraminal stenosis at L2-3 and L3-4 on the appropriate side. The patient was taken to surgery in September 1993, after prolonged medical therapy, and foraminotomy was carried out on the right side at L23 and L3-4. Instead of improving, the patient began to limp and discovered that he could not walk well up and down stairs. In July 1995 it was obvious that quadriceps wasting was present and weakness was easy to demonstrate. The previous electromyographer, consulted again, believed the problem was still a lumbar radiculopathy. A second electromyographer was consulted, who demonstrated electrically, to our mutual satisfaction, that the abnormality was limited to femoral nerve innervated structures. There was no history of surgery in the abdomen or groin. In August 1995 the patient un655 Avenue

0 1997 by Elsevier Science Inc. of the Americas, New York, NY 10010

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derwent retroperitoneal release of the femoral nerve entrapped at the iliopectineal arch. The nerve appeared normal, but was tightly compressed at the iliopectineal arch. The patient noted immediate relief of pain and by the sixth postoperative day, without consulting his surgeon, walked one-half mile to see if the pain would come back. It did not. The patient’s strength returned virtually to normal. CASE 2 This 57-year-old housewife complained of pain in the hip radiating into the thigh in December 1994. She was evaluated by a general surgeon for femoral hernia and none was found. An orthopedic surgeon was consulted who felt that the problem was in the hip and/or the greater trochanter, which he injected. An MRl of the lumbar spine was requested, which was normal. The patient’s subjective numbness was felt to be in the L2 distribution. In April 1995 the patient consulted the author and weakness of the quadriceps associated with early atrophy was noted. An EMG demonstrated partial denervation in the muscles innervated by the femoral nerve. The patient had no history of surgery adjacent to the femoral nerve. In July 1995, a retroperitoneal exploration of the femoral nerve demonstrated a tight compression band at the iliopectineal arch. The nerve itself appeared normal. The patient experienced immediate postoperative relief of pain and restoration of strength and has remained well. CASE 3 This 38yearold man developed right hip and leg pain in 1988. He consulted an orthopedic surgeon and a lumbar discectomy was performed without obvious benefit. The patient’s proximal leg gradually weakened and atrophied and he had difficulty ascending and descending the stairs. He denied back pain before or after his back surgery and returned to work. He came for neurosurgical consultation in January 1995, which revealed that his right quadriceps mechanism was trace to l+. EMC showed chronic denervation in the distribution of the femoral nerve. A lumbar MRI scan showed postoperative changes. There was no history of abdominal or inguinal surgery. Retroperitoneal exploration and neurolysis of the femoral nerve at the iliopectineal arch was performed. There was a thickened membrane over the femoral nerve leading to the tight iliopectineal arch, which was also transected. This suggested a previous hematoma or abscess in that location. The patient’s pain was immediately relieved in the postoperative period and his function was almost antigravity 1 day after

Hemostat is under the right femoral nerve. The auqtopsy thor’s index finger is under iliopectineal arch. Auspecimen.

surgery. It rapidly became antigravity and has continued to improve, but is still not quite normal.

DISCUSSION The femoral nerve is formed by contributions from L2, L3, and L4 behind the psoas muscle and presents between the psoas and iliacus muscle lateral and deep to the iliac artery. It runs underneath a thin fascial membrane on the ventral or abdominal side of the psoas muscle and is usually visible through the fascia. The psoas muscle and the femoral nerve continue together under the iliopectineal arch, which is a structure omitted in most anatomy books but described in Hollingshead [5]. The psoas muscle eventually attaches to the lesser trochanter (Figure l), and if the nerve is approached from below the inguinal ligament, the psoas muscle appears between the femoral artery on the medial side and the femoral nerve on the lateral side of the tendon. The iliac vein is more medial than the artery and will not be seen in a limited dissection. The femoral nerve innervates a portion of the psoas muscle before it passes underneath the iliopectineal arch; and almost immediately after passing into the femoral triangle, breaks up into a number of branches of which the sensory branches are more superficial. Included in these branches are the intermediate cutaneous nerve of the thigh, the medial cutaneous nerve of the thigh, and the saphenous nerve whose infrapatellar branch passes just underneath the kneecap. The muscles innervated by the femoral nerve include pectineus, sartorius, rectus femoris, vastus lateralis, vastus intermedius, and vastus medialis. The iliopectineal arch is an obvious source of entrapment in the cadaver as it is

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quite firm and the nerve must change direction at this point. When the nerve is tightly bound, it can be subjected to trauma by motion at the hip joint or expansion of the psoas muscle. It is reasonable to postulate ischemic entrapment during vaginal delivery or gynecologic surgery in the lithotomy position for a prolonged period of time. THE SURGICAL APPROACH The author has employed a low retroperitoneal approach and has encountered no surgical morbidity or complication. Arthur Cushman, M.D., a neurosurgeon in Madison, Tennessee, after hearing the author discuss these cases, encountered two similar cases and reported that he was able to transect the iliopectineal ligament with the laparoscope with excellent results in both. An additional case is now presented with a somewhat similar clinical syndrome but entirely different pathology. CASE 4 This 34year-old female attorney presented in 1988, 3 months after vaginal hysterectomy with A&P repair, complaining of radiating pain into the hip and the medial thigh. There was no obvious weakness or reflex change. Palpation of the femoral nerve produced an increase in symptoms only if pressure was applied. Retroperitoneal exploration, as described earlier, revealed that the intermediate femoral cutaneous nerve took an early origin from the femoral nerve and descended to the groin separately. This branch of the nerve was involved in an adhesive process that drew it to the midline in such a way that the remainder of the femoral nerve was tented up underneath the fascia of the psoas muscle. The length of the adhesion was less than 1 cm. The adhesion was transected with no attempt at neurolysis. The body of the femoral nerve relaxed when this was accomplished. The patient noted immediate relief, which has persisted. In summary, there is an entrapment syndrome of the femoral nerve at the iliopectineal arch that is uncommon but characteristic. Pain into the ipsilatera1 hip region as far down as the knee, paresthesia, and actual weakness of the quadriceps leading to wasting are characteristic of this condition. Correct performance and interpretation of the EMG is crucial to obtaining the diagnosis. The operation is straightforward and perhaps laparoscopic transection of the iliopectineal arch may be appropriate in similar cases. Excellent results are the rule. REFERENCES 1. Berlusconi M, Capitani D. Post-traumatic hematoma of the iliopsoas muscle with femoral nerve entrap-

ment: description

of a rare occurrence in a profes-

sional cyclist. Ital J Orthop Traumatol

1991;17:563-6. 2. Calverley JR, Mulder DW. Femoral neuropathy due to psoas hematoma revisited: report of three cases with serious outcomes. Spine 1992;17:724-6. 3. Coppola AR. Femoral neuropathy. Va Med Q 1974;lOl: 854-5. 4. Hakim MA, Katirii MB. Femoral mononeuropathy induced by the lithotomy position: a report of five cases with a review of literature. Muscle Nerve 1993;16: 891-5. 5. Hollingshead WH. Textbook of anatomy, 3rd ed. Hag-

erstown: Harper & Row, 1974:397-g. 6. Hudson AR, Hunter GA, Waddell JP. Iatrogenic femoral nerve injuries. Can J Surg 1979;22:62-6. 7. Jamjoom ZB, Al-Bakry A, Al-Momen A, Malabary T, Tahan AR, Yucub B. Bilateral femoral nerve compression by uliacus hematomas complicating anticoagulant therapy. Surg Today 1993;23:535-40. 8. Kim DH, Kline DC. Surgical outcome for intra- and extrapelvic femoral nerve lesions. J Neurosurg 1995; 83:783-90. 9. Kirchner R, Halbfass HJ, Martin L. Kompression syn-

drom des nervus femoralis infolge retropertonealer blutung. Chirurg 1981;52:409-11. 10. Kumar S, Ananthan J, Won Z. Case report: posttraumatic hematoma of iliacus muscle with paralysis of the femoral nerve. J Orthop Trauma 1992;6:110-2. 11. Letourneau L, Dessureault M, Carette S. Rheumatoid

iliopsoas bursitis presenting as unilateral nerve palsy. J Rheumatol 1991;18:462-3.

femoral

12. Miller EH, Benedict FE. Stretch of the femoral nerve in a dancer. J Bone Joint Surg [Am] 1985;67-A:315-7. 13. Naude RJT, Thomson SR. Femoral nerve palsy following a subperiosteal haematoma. Injury 1993;24:62-3. 14. Navarro RA, Schmalzried TP, Amstutz HC, Dovey FJ. Surgical approach and nerve palsy in total hip arthroplasty. J Arthroplasty 1995;10:1-5. 15. Papastefanou SL, Stevens K, Mulholland RC. Femoral nerve palsy. Spine 1994;19:2842-4. 16. Pham LT, Bulich LA, Datta S. Bilateral postpartum

femoral neuropathy. Anesth Analg 1995;80:1036-7. 17. Razzuk MA, Linton RR, Darling RC. Femoral neuropathy secondary to ruptured abdominal aortic aneurysms with false aneurysms. JAMA 1967;201:139-40. 18. Rottenberg ME, DeLisa JA. Severe femoral neuropathy with “Hanging Leg” syndrome. Arch Phys Med

Rehabil 1981;62:404-6. 19. Sammarco GJ, Stephens MM. Neurapraxia of the femoral nerve in a modern dancer. Am J Sports Med 19:413-4. 20. Simmons C, Izant TH, Rothman RH, Booth RE, Balderston RA. Femoral neuropathy following total hip ar-

throplasty. J Arthroplasty

1991;6:559-66.

21. Smedh K, Olaison G, Nystrom PO, Hillman J, Sjodahl R. Femoral nerve neurilemmoma in the iliac fossa. Ann Chir Gynaecol 1993;82:62-65. 22. Solheim L, Hagen R. Femoral and sciatic neuropathies after total hip arthroplasty. Acta Orthop Stand 1980; 51:531-4. 23. Walsh C, Walsh A. Post-operative femoral neuropathy. Obstet Gynecol 1992;174:255-63. 24. Warfel BS, Marini SG, Lachman EA, Nagler W. Delayed femoral nerve palsy following femoral vessel catherization. Arch Phys Med Rehabil 1993;74:121 l-5.

Surg Neurol 1997;48:326-9

Femoral Nerve Entrapment

25. Young MR, Norris JW. Femoral neuropathy during anticoagulant therapy. Neurology 1976;26:1173-5. COMMENTARY

Natelson presents in some detail three patients who appear to have spontaneous entrapments of the femoral nerve at the iliopectineal arch. These individuals were helped by release of the nerve at a retroperitoneal level. In a series of 94 femoral neuropathies, where 78 required operation because of deficit and/or pain, we did not see any spontaneous nontumorous neuropathies [ 11. In each case, there was either some history of trauma or there had been an operation on abdomen, thigh, or pelvis. Thus, Natelson’s cases are a welcome addition to the literature. In addition to sending out a prior precipitating history, the patient with femoral distribution pain or loss of seemingly spontaneous origin should always have diabetes mellitus ruled out. The lower pelvic retroperitoneal portion of the femoral nerve can also be exposed by a thigh-tolower quadrant incision by splitting the obliques and then dissecting in a retroperitoneal fashion. David G. Kline,

M.D.

Department of Neurosurgery Louisiana State University New Orleans, Louisiana

syndrome: a primary entrapment of the femoral nerve at the iliopectineal arch. These patients were a 38year-old man, a 67-year-old man, and a 57-yearold woman. The clinical picture consisted of hip pain radiating to the leg, but only as far down as the knee (it would be interesting to study why the pain does not radiate beyond the knee down to the ankle, along the innervation of the saphenous nerve), and weakness of the quadriceps. At the time the femoral nerve was decompressed, the two men had experienced symptoms for 4 and 7 years, respectively; the woman for 6-7 months. One man had undergone a foraminotomy at L&L3 and L3-L4, and the other had had a lumbar diskectomy. The woman was previously treated by injecting an unknown substance into the hip and the greater trochanter. In all patients, EMG revealed denervation of the muscles supplied by the femoral nerve. As the femoral nerve divides into its terminal branches deep to the inguinal ligament, Dr. Natelson decided to perform a retroperitoneal exploration in all three patients. He found the femoral nerve entrapped at the iliopectineal arch and released it. Two patients recovered completely and one improved significantly. The author concludes that excellent results are the rule even after the release of the iliopectineal arch. In the future, other similar experiences will surely

REFERENCE 1. Kim D, Kline D. Surgical outcome for intra- and extrapelvic femoral nerve lesions. J Neurosurg 1995;83: 783-90.

Dr. Natelson had a very singular experience during 1995. In fact, he had the opportunity to treat three patients with a new peripheral nerve entrapment

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be reported;

thus this syndrome

not so rare if, in only 8 months, served three cases.

in reality

Dr. Natelson

Eduardo Femandez, Enrico Marchese,

is

obM.D. M.D.

Istituto di Neurochinrrgia Universitci Cattolica de1Sacro Cuore Rome, Italy