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Nerve injury associated with laparoscopic inguinal herniorrhaphy
Nerve injury associated with laparoscopic inguinal herniorrhaphy Prakash Sampath, MD, Charles J. Yeo, MD, and James N. Campbell, MD, Baltimore, Md.
Background. As laparoscopic herniorrhaphy becomes more popular, it is important to realize the potential for injury to surrounding neural structures, with attendant severe disability. Methods. Herein are discussed two patients with disabling neuralgia afier laparoscopic herniorrhaphy. Results. Both patients were treated with transabdominal removal of their prosthetic materials and anchoring staples, with dramatic symptomatic improvement. Conclusions. The surgeon should be aware of the anatomic considerations accompanying laparoscopic herniorrhaphy. In regard to nerve injury, laparoscopic herniorrhaphy may pose certain disadvantages over traditional hernia repairs. It may diminish the ability to appreciate the course of nerves in the inguinal region and their relationship to the spermatic cord, and injury to nerves may be difficult to recognize and treat. (SuRcERY 1995;118:829-33.) From the Departments of Neurosurgery and Surgery, TheJohns Hopkins University School of Medicine, Baltimore, Md.
INTRAOPERATIVE COMPI,ICATIONSd u r i n g o p e n inguinal
h e r n i o r r h a p h y are u n c o m m o n but are well known to the surgeon. Traditional inguinal herniorrhaphy, a technique that has been improved a n d refined since Bassini's description in 18841 has a high success rate. However, accidental injury to the intestine, urinary bladder, contents of the hernia sac, structures of the spermatic cord, a n d s u r r o u n d i n g vascular a n d nervous structures have all been described. 2 In an a t t e m p t to avoid some of these complications, a n d to improve patient comfort and reduce recurrence rates, the so-called tension-free hernia repair has been popularized by using extraperitoneal prosthetic mesh. 35 An extension of this technique d u r i n g the era o f minimally invasive surgery has b e e n the introduction o f laparoscopic hernia repair, placing mesh via a transperitoneal approach. Today there is increasing enthusiasm for laparoscopic h e r n i a repair. 6"9 The technique involves posterior prosthetic patching over Hesselbach's triangle a n d the internal inguinal ring (deep ring) without the n e e d for fascial apposition. T h e mesh is a n c h o r e d in place by staples a n d m a i n t a i n e d in position by i n t r a a b d o m i n a l pressure. Proponents o f the laparoscopic m e t h o d of h e r n i a repair cite advantages such as improved patient comfort, less a b d o m i n a l pain, fewer complications, a n d earlier return to n o r m a l activities.79 T h e rate o f h e r n i a
Accepted for publication March 9, 1995. Reprint requests: Charles J. Yeo, MD, Department of Surgery, The Johns Hopkins Hospital,Blalock606, 600 N. WolfeSt., Baltimore, MD 21287-4606. Copyright 9 1995 by Mosby-YearBook, Inc. 0039-6060/95/$5.00 + 0 11/56/65397
recurrence over long-term follow-up after laparoscopic h e r n i o r r h a p h y is presently unknown. A n u m b e r o f complications of laparoscopic h e r n i a repair are now b e i n g recognized. Complications direcdy associated with general anesthesia, urinary bladd e r injury, intestinal perforation, osteitis pubis, injury to major vessels, a n d bowel obstruction caused by adhesions from the laparoscopically placed mesh have all been described, s-l~ In addition, reports of injury to neural structures coursing through the groin have b e e n published 8, 10, l 1-13as the use of laparoscopic h e r n i a repair increases. In this article we discuss two patients with injury to neural structures occurring as a result of iaparoscopic h e r n i o r r h a p h y .
CASE R E P O R T S Patient 1. A 35-year-old man presented with right-sided groin pain and swelling of 3 months' duration. Examination revealed a right indirect inguinal hernia and repair was recommended. The patient elected laparoscopic hernia repair, performed at his local community hospital. At laparoscopy the peritoneum surrounding the lateral and medial aspect of the inferior epigastric vessels was opened, and dissection was carried down to expose the inguinal endopelvic fascia and internal inguinal ring. A moderate-sized right indirect hernia was identified and reduced. Further dissection identified the pubic tubercle, ilioinguinal ligament, and Cooper's ligament medially and the epigastric and femoral vessels anteriorly. A 10 x 8 cm piece of polypropylene (Marlex; Bard Vascular Systems, Billerica, Mass.) mesh was inserted to cover the arc of the pubic tubercle, Cooper's ligament, and the anterior conjoined tendon. The mesh was stapled in place both medial and lateral to the endopelvic fascia and then partially covered with peritoneum, as has been previously described. 14 On awakening from general anesthesia, the patient comSURGERY
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Fig. 1. Schematic diagram depicts anterior view of right lumbar nerve roots and their branches. Inguinal region receives sensory innervation from Tr2 to L4.
plained of swelling and sharp, stabbing pain in the region of the right groin and thigh. During the next few months the pain resolved partially, but the patient experienced persistent numbness in his right groin, scrotum, and anterior thigh. In addition, he experienced dyspareunia with retrograde ejaculation. The patient underwent extensive workup for continued pain, numbness, and worsening sexual function. Magnetic resonance imaging of his lumbosacral spine and pelvis failed to reveal nerve root compression or morphologic abnormality within the distribution of the lumbar plexus. During this time the patient was seen, evaluated, and treated by several different physicians with no improvement in his symptoms. Examination at The Johns Hopkins Hospital 1 year after his laparoscopic hernia repair revealed altered sensation over the fight anterior thigh and groin in the distribution of the lateral femoral cutaneous nerve. Strength of the thigh muscles and patellar reflex were normal. The patient elected surgical exploration of the previous herniorrhaphy site. A transabdominal approach was used, and the fight pelvis was exposed. The polypropylene mesh was found to extend from the pubic tubercle laterally beyond the internal ring close to the anterior superior iliac spine. Exuberant scarfing was noted in the area around the lateral femoral cutaneous nerve, and a staple had been placed directly through the middle of the nerve, anchoring the mesh in place. The staple was removed, and the nerve was dissected free of the overlying mesh and left intact. Further
Fig. 2. Illustration depicts positions of lateral femoral cutaneous nerve on iliacus muscle, femoral nerve, and two branches of genitofemoral nerve on psoas muscle. dissection identified an uninjured femoral nerve. The genitofemoral nerve entered the area of the mesh and could not be followed further because of scarring; it was divided in its location overlying the psoas muscle. The polypropylene mesh lateral to the internal ring was rem(wed but w'as left intact in the area of Hesselbach's triangle. Immediately after the operation the patient noted a marked improvement in his fight groin and thigh pain. Twelve-month follow-up revealed improving residual dysesthetic sensations in his right groin and anterior thigh. His sexual function returned toward normal as his pain improved. Patient 2. A 47-year-old woman presented with left groin pain and a bulge of 1 month's duration. Examination revealed a left femoral hernia and repair was recommended. Laparoscopic hernia repair was performed at her local community hospital. At laparoscopy the femoral hernia was reduced, and a Gore-Tex (W.L. Gore and Associates Inc., Flagstaff, Ariz.) patch was stapled to Cooper's ligament (from the pubic tubercle to the iliac vein), circumferentially around the iliac vessels, and lateral to the vessels. Immediately after laparoscopic herniorrhaphy the patient required a 3-day hospital admission for control of pain in her left groin and anterior thigh. Her pain failed to improve during the next few months, despite oral narcotic analgesics and multiple evaluations by her treating surgeons. The patient presented to The Johns Hopkins Hospital 4 months after laparoscopic herniorrhaphy. Examination revealed no hernia and an ilioinguinal-lateral femoral cutaneous
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T a b l e I. E n t r a p m e n t neuropathies
Genitofemoral
Sensory changes
Posterior abdominal wall, femoral or inguinal region Groin, scrotum, upper thigh Hyperalgesia
Point tendemess
Internal inguinal ring
Hip joint movement
Hyperextension or external rotation of hip increases pain Loss of cremasteric reflex; ejaculatory dysfunction
Common site of entrapment Pain
Associated signs
neuralgia. The patient elected exploration of the previous herniorrhaphy site. Via a transabdominal approach the GoreTex patch was found to extend from the internal ring to the midline, being held in position circumferentially by at least 25 metallic staples. The Gore-Tex patch was completely removed, as were all staples, one of which had pierced the lateral femoral cutaneous nerve. No inguinal or femoral hernias were identified after patch removal. Immediately after the operation the patient noted nearly complete relief of her left groin pain, which had been maintained at 6-month follow-up. She had no evidence of recurrent hernia.
DISCUSSION Injury to s u r r o u n d i n g neural structures d u r i n g traditional inguinal h e r n i o r r h a p h y is a well-recognized complication and is well known to most surgeons. 2' 15 Nerves e n c o u n t e r e d d u r i n g open h e r n i o r r h a p h y are normally protected from injury but sometimes may be severed o r e n t r a p p e d leading to n e u r o m a formation or pain. Neural injury or e n t r a p m e n t after laparoscopic herniorrhaphy has been described, s' 10, 1H.~ with most cases being transient and requiring no specific therapy. However, as illustrated by these two cases a n d described by others, ll'Ls severe nerve injury can accompany laparoscopic inguinal h e r n i a repair, requiring additional surgical intervention for successful management. For example, Eubanks et al. 11 have described five patients with severe groin pain after laparoscopic hernia repair, three of whom required repeat laparoscopy for removal o f staples placed t h r o u g h the lateral femoral cutaneous nerve. The inguinal region, which includes the spermatic cord, inguinal canal, a n d s u r r o u n d i n g subcutaneous tissue, skin, a n d musculoskeletal a n d neurovascular structures, receives sensory innervation e x t e n d i n g from the twelfth thoracic nerve (T12) to the ventral b r a n c h
Ilioinguinal
Femoral
Medial to anterior superior iliac spine
Posterior abdominal wall posterior to inguinal ligament Groin, anterior and medial thigh Hyperalgesia or dysesthesia
Groin, scrotum, flank Hypoalgesia or hyperalgesia Medial to anterior superior iliac spine; anterior abdomen Limitation of internal rotation; extension of hip increases pain Weakness of lower abdominal wall
None
Minimal hip extension increases pain Quadraceps muscle weakness and atrophy; loss of patellar reflex
of the fourth l u m b a r r o o t (L4) (Fig. 1). T h e cutaneous branches o f the l u m b a r plexus include the iliohypogastric, ilioinguinal, femoral, lateral femoral cutaneous, genitofemoral, a n d o b t u r a t o r nerves. In m e n the testes also receive innervation from the spermatic sympathetic plexus. T h e genitofemoral nerve arises from the first a n d second l u m b a r vertebral plexus. It descends dorsal to the parietal p e r i t o n e u m on the surface o f the psoas muscle befbre bifurcating into the genital and femoral branches (Fig. 2). T h e genital branch (external spermatic nerve) traverses the internal inguinal ring to supply the cremaster muscle in m e n and the skin o f the mons pubis a n d labium majus in women. T h e femoral branch (lumboinguinal nerve) o f the g e n i t o f e m o r a l nerve is the cutaneous nerve to the femoral triangle. Inj u r y to this nerve (so-called genitofemorai neuralgia) results in constant b u r n i n g o r sharp pain in the inguinal region (Table I) radiating to the genitalia a n d the medial u p p e r thigh. 16' 17 T h e ilioinguinal nerve is f o r m e d from the first lumb a r nerve. It courses retroperiteoneally before piercing the transversus abdominis muscle near the anterior iliac crest. In stepwise fashion it courses t h r o u g h both the transversus abdominis a n d internal oblique muscles to e m e r g e t h r o u g h the external inguinal ring (Fig. 3). A frequent anatomic variation is an a b e r r a n t sensory trunk that j o i n s with the genital b r a n c h of the genitofemoral nerve. Ilioinguinal e n t r a p m e n t (Table I) has effects similar to those o f genitofemoral neuralgia, with pain a n d b u r n i n g in the inguinal region a n d groin. 18' 19 T h e femoral nerve (L2-L4) traverses the pelvis between the psoas a n d iliacus muscles to course u n d e r the inguinal ligament lateral to the femoral artery. T h e lateral femoral cutaneous nerve (L2-L3) follows a m o r e
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Fig. 3. Illustration depicts position of ilioinguinal nerve as it traverses inguinal canal and exits through external inguinal ring to enter hemiscrotum. In some cases the ilioinguinal nerve may innervate investing structures of the testicle, as shown here. In many cases the terminal branches of the ilioinguinal nerve do not reach the testicle and instead supply the lower groin and upper scrotal area. lateral retroperitoneal path, typically coursing through the inguinal ligament. Injury to either of these nerves can cause pain and associated sensory loss to the lateral upper thigh. ~~ Motor weakness of the quadriceps muscles with loss of the patellar reflex is a hallmark of femoral neuropathy (Table I). It is often difficult to diagnose severe nerve injury after inguinal herniorrhaphy because transient anesthesia or pain in the distribution of one of these nerves is not an u n c o m m o n postoperative occurrence. Because the sensory distribution of nerves in the inguinal region overlaps, a specific entrapment syndrome in a given patient may be difficult to recognize initially. Severe pain (neuralgia) with sensory complaints immediately after operation should alert the surgeon to the possibility of nerve entrapment and, if persistent, should p r o m p t further investigation. Radiographic studies such as pelvic magnetic resonance imaging, percutaneous nerve or facet blocks that alleviate pain at a particular spinal level, or nerve conduction studies may be helpful in determining specific nerve involvement. As laparoscopic herniorrhaphy becomes more popular, the possibility of nerve injuries related to the procedure may increase. Nerve injury may be one of the more c o m m o n (albeit unrecognized) postoperative causes
Surgery November 1995 for patient discomfort and should be an important consideration to the surgeon. There are several reasons for nerve injury during laparoscopic herniorrhaphy. First, the ability to identify and follow the course of a nerve in the operative field may be diminished during laparoscopic repair. The ilioinguinal nerve, for example, may be seen piercing the transversus abdominis muscle, but its passage through the oblique muscles and its relationship to the spermatic cord may not be easy to determine. This may lead to the inadvertent stapling of a prosthetic patch to the nerve. Avoidance of placing deep staples lateral to the internal inguinal ring in the endopelvic fascia may reduce ilioinguinal nerve injury, but the frequent anatomic variation encountered with nerves in this region means that nerve injury is possible even if appropriate care is taken. Second, the laparoscopic surgeon's ability to transpose or divide an encountered nerve to prevent neuroma formation or scarring may be more limited than with open approaches. Further, although laparoscopic reoperation to correct nerve injury has been successful for simple staple removal, 11 it may not be appropriate for all cases. This becomes a specific problem when a nerve is accidentally severed or injured during dissection or hernia repair. U n d e r such circumstances if the nerve does not require repair it is important to separate the free ends of a nerve to avoid subsequent n e u r o m a formation and involvement with the mesh and to sharply divide the nerve as proximal as possible. Nerves encountered during herniorrhaphy that can be sacririced with minimal chance of long-term morbidity include the genitofemoral and ilioinguinal nerves. Injury to the femoral nerve requires repair, because this nerve provides motor input to the muscles of the anterior thigh. Third, the genitofemoral nerve with its course through the internal inguinal ring may be more susceptible to injury via the laparoscopic approach. In patient 1 previously described, the genitofemoral nerve was scarred beneath the mesh and was impossible to dissect free. With the mesh being placed over the internal ring, the genitofemorai nerve may be at risk for compression by the mesh, especially if fibrosis occurs adjacent to the mesh. As with all new procedures a learning curve is associated with laparoscopic herniorrhaphy. Inexperience or lack of knowledge and familiarity of the inguinal anatomy as seen laparoscopically may result in surgical mishaps involving misplacement of prosthetic patches or staples, which can lead to nerve injuries. Furthermore, as experience with laparoscopic hernia repair increases, modifications in repair technique may decrease the risk of nerve injury. For example, it is now considered a mistake by some authorities to place staples dorsal to the iliopubic tract, lateral to Cooper's ligament, in the
Surgery Volume 118, Number 5 so-called z o n e o f d a n g e r , 21' 22 t h u s r e d u c i n g t h e risk o f i n j u r y to t h e iliac a r t e r y a n d vein a n d lateral f e m o r a l cut a n e o u s n e r v e . Also, i m p r o v e m e n t s in l a p a r o s c o p i c e q u i p m e n t m a y r e d u c e t h e risk o f n e r v e injury. M a n y o f t h e c u r r e n t i n t e r n a l s t a p l i n g devices u s e d to a n c h o r mesh in place have deep depths of staple penetration, which can inadvertently injure neural structures. Even in the hands of experienced laparoscopic hernia surgeons, some patients may have nerve injury and a s s o c i a t e d n e u r a l g i a . Early r e o p e r a t i v e n e r v e d e c o m pression in properly selected patients may be the best way to m a n a g e t h e s e difficulties. I n s o m e cases l a p a r o scopic reoperation may provide adequate visualization to allow f o r a s s e s s m e n t o f t h e n e r v e i n j u r y a n d a p p r o priate repair. In other circumstances open transabdominal e x p l o r a t i o n m a y b e n e e d e d . T h e c h a l l e n g e is to i d e n t i f y w h i c h p a t i e n t s h a v e n e r v e i n j u r y t h a t will n o t i m p r o v e w i t h o u t t r e a t m e n t a n d to d i r e c t a p p r o p r i a t e and prompt treatment. We thank Ms. D o n n a Cavi for the original illustrations. REFERENCES
1. Bassini E. Nuovo metodo per la cura radicale dell'ernia. Atti Cong Ass Med Ital 1887;2:179. 2. Nyhus LM, Bombeck C'I', Klein MS. Hernias. In: Sabiston DC, ed. Textbook of surgery: the biological basis of modern surgical practice. 14th ed. Philadelphia: WB Saunders Co, 1991:1134-48. 3. Lichtenstein IL, Schulman AG, Amid PK. The tension free hernioplasty. AmJ Surg 1989;157:188-93. 4. RivesJ. Surgical treatment of the inguinal hernia by the Dacron patch: principles, indications, technique and results. Int Surg 1967;47:360-4. 5. Schulman AG, Amid PK, Lichenstein IL. The safety of mesh repair for primary inguinal hernia--results of 3019 operations from five diverse surgical sources. Am Surg 1992;58:255-7.
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6. CorbittJD. Laparoscopic herniorrhaphy. Surg Laparosc Endosc 1991;1:23-5. 7. Ger R, Monroe K, Duvivier R. Management of indirect inguinal hernias by laparoscopic closure of the neck of the sac. AmJ Surg 1990;159:371-3. 8. Payne JH, Grininger LM, Izawa MT, Podoll EF, Lindahl PJ, Balfour J. Laparoscopic or open inguinal herniorrhaphy? A randomized prospective trial. Arch Surg 1994;129:973-81. 9. McKernanJB, Laws HL. Laparoscopic repair of inguinal hernias using a totally extraperitoneal prosthetic approach. Surg Endosc 1993;7:26-8. 10. MacFayden BV, Arregui ME, CorbittJD Jr, et al. Complications of laparoscopic herniorrhaphy. Surg Endosc 1993;7:155-8. 11. Eubanks S, Newman L III, Goehring L, et al. Meralgia paresthetica: a complication of laparoscopic herniorrhaphy. Surg Laparosc Endosc 1993;3:381-5. 12. Kraus MA. Laparoscopic identification of preperitoneal nerve anatomy in the inguinal region. Surg Endosc 1994;8:377-81. 13. Seid AS, Amos E. Entrapment neuropathy in laparoscopic hemiorrhaphy. Surg Endosc 1994;8:1050-3. 14. Toy FK, Smoot RTJr. Laparoscopic hernioplasty update. J Laparoendosc Surg 1992;2:19%205. 15. Condon RE, Nyhus LM. Complications of groin hernia and of hernia repair. Surg Clin North Am 1971;51:1325-36. 16. Lala RK, Rat S, Pidgeon CN, Dujovny M. Genitofemoral neuralgia. Surg Neurol 1977;8:280-2. 17. Harms BA, DeHaas DR, StarlingJR. Diagnosis and management of genitofemoral neuralgia. Arch Surg 1984;119:339-41. 18. Starling JR, Harms BA, Schroeder ME, Richman PI.. Diagnosis and treatment of genitofemoral and ilioinguinal entrapment neuralgia. SURGERY1987;102:581-6. 19. Kopell HP, Thompson WAL, Postel AH. Entrapment neuropathy of the ilioinguinal nerve. N Engl J Med 1962;226:16-9. 20. Moosman DA, Oelrigh TM. Prevention of accidental trauma to the ilioinguinal nerve during inguinal herniorrhaphy. AmJ Surg 1977; 133:146-8. 21. Fitzgibbons RJ, CampsJ, Cornet DA, et al. Laparoscopic inguinal herniorrhaphy: results ofa multicenter trial. Ann Surg 1995;221: 3-13. 22. Talamini MA. Hernia complications. Laparosc Sttrg 1994;2:114-9.
Background. As laparoscopic herniorrhaphy becomes more popular, it is important to realize the potential for injury to surrounding neural structures, with attendant severe disability. Methods. Herein are discussed two patients with disabling neuralgia afier laparoscopic herniorrhaphy. Results. Both patients were treated with transabdominal removal of their prosthetic materials and anchoring staples, with dramatic symptomatic improvement. Conclusions. The surgeon should be aware of the anatomic considerations accompanying laparoscopic herniorrhaphy. In regard to nerve injury, laparoscopic herniorrhaphy may pose certain disadvantages over traditional hernia repairs. It may diminish the ability to appreciate the course of nerves in the inguinal region and their relationship to the spermatic cord, and injury to nerves may be difficult to recognize and treat. (SuRcERY 1995;118:829-33.) From the Departments of Neurosurgery and Surgery, TheJohns Hopkins University School of Medicine, Baltimore, Md.
INTRAOPERATIVE COMPI,ICATIONSd u r i n g o p e n inguinal
h e r n i o r r h a p h y are u n c o m m o n but are well known to the surgeon. Traditional inguinal herniorrhaphy, a technique that has been improved a n d refined since Bassini's description in 18841 has a high success rate. However, accidental injury to the intestine, urinary bladder, contents of the hernia sac, structures of the spermatic cord, a n d s u r r o u n d i n g vascular a n d nervous structures have all been described. 2 In an a t t e m p t to avoid some of these complications, a n d to improve patient comfort and reduce recurrence rates, the so-called tension-free hernia repair has been popularized by using extraperitoneal prosthetic mesh. 35 An extension of this technique d u r i n g the era o f minimally invasive surgery has b e e n the introduction o f laparoscopic hernia repair, placing mesh via a transperitoneal approach. Today there is increasing enthusiasm for laparoscopic h e r n i a repair. 6"9 The technique involves posterior prosthetic patching over Hesselbach's triangle a n d the internal inguinal ring (deep ring) without the n e e d for fascial apposition. T h e mesh is a n c h o r e d in place by staples a n d m a i n t a i n e d in position by i n t r a a b d o m i n a l pressure. Proponents o f the laparoscopic m e t h o d of h e r n i a repair cite advantages such as improved patient comfort, less a b d o m i n a l pain, fewer complications, a n d earlier return to n o r m a l activities.79 T h e rate o f h e r n i a
Accepted for publication March 9, 1995. Reprint requests: Charles J. Yeo, MD, Department of Surgery, The Johns Hopkins Hospital,Blalock606, 600 N. WolfeSt., Baltimore, MD 21287-4606. Copyright 9 1995 by Mosby-YearBook, Inc. 0039-6060/95/$5.00 + 0 11/56/65397
recurrence over long-term follow-up after laparoscopic h e r n i o r r h a p h y is presently unknown. A n u m b e r o f complications of laparoscopic h e r n i a repair are now b e i n g recognized. Complications direcdy associated with general anesthesia, urinary bladd e r injury, intestinal perforation, osteitis pubis, injury to major vessels, a n d bowel obstruction caused by adhesions from the laparoscopically placed mesh have all been described, s-l~ In addition, reports of injury to neural structures coursing through the groin have b e e n published 8, 10, l 1-13as the use of laparoscopic h e r n i a repair increases. In this article we discuss two patients with injury to neural structures occurring as a result of iaparoscopic h e r n i o r r h a p h y .
CASE R E P O R T S Patient 1. A 35-year-old man presented with right-sided groin pain and swelling of 3 months' duration. Examination revealed a right indirect inguinal hernia and repair was recommended. The patient elected laparoscopic hernia repair, performed at his local community hospital. At laparoscopy the peritoneum surrounding the lateral and medial aspect of the inferior epigastric vessels was opened, and dissection was carried down to expose the inguinal endopelvic fascia and internal inguinal ring. A moderate-sized right indirect hernia was identified and reduced. Further dissection identified the pubic tubercle, ilioinguinal ligament, and Cooper's ligament medially and the epigastric and femoral vessels anteriorly. A 10 x 8 cm piece of polypropylene (Marlex; Bard Vascular Systems, Billerica, Mass.) mesh was inserted to cover the arc of the pubic tubercle, Cooper's ligament, and the anterior conjoined tendon. The mesh was stapled in place both medial and lateral to the endopelvic fascia and then partially covered with peritoneum, as has been previously described. 14 On awakening from general anesthesia, the patient comSURGERY
829
830
Sampath et al.
Surgery November 1995
F'el:
,0
Lal:
Fig. 1. Schematic diagram depicts anterior view of right lumbar nerve roots and their branches. Inguinal region receives sensory innervation from Tr2 to L4.
plained of swelling and sharp, stabbing pain in the region of the right groin and thigh. During the next few months the pain resolved partially, but the patient experienced persistent numbness in his right groin, scrotum, and anterior thigh. In addition, he experienced dyspareunia with retrograde ejaculation. The patient underwent extensive workup for continued pain, numbness, and worsening sexual function. Magnetic resonance imaging of his lumbosacral spine and pelvis failed to reveal nerve root compression or morphologic abnormality within the distribution of the lumbar plexus. During this time the patient was seen, evaluated, and treated by several different physicians with no improvement in his symptoms. Examination at The Johns Hopkins Hospital 1 year after his laparoscopic hernia repair revealed altered sensation over the fight anterior thigh and groin in the distribution of the lateral femoral cutaneous nerve. Strength of the thigh muscles and patellar reflex were normal. The patient elected surgical exploration of the previous herniorrhaphy site. A transabdominal approach was used, and the fight pelvis was exposed. The polypropylene mesh was found to extend from the pubic tubercle laterally beyond the internal ring close to the anterior superior iliac spine. Exuberant scarfing was noted in the area around the lateral femoral cutaneous nerve, and a staple had been placed directly through the middle of the nerve, anchoring the mesh in place. The staple was removed, and the nerve was dissected free of the overlying mesh and left intact. Further
Fig. 2. Illustration depicts positions of lateral femoral cutaneous nerve on iliacus muscle, femoral nerve, and two branches of genitofemoral nerve on psoas muscle. dissection identified an uninjured femoral nerve. The genitofemoral nerve entered the area of the mesh and could not be followed further because of scarring; it was divided in its location overlying the psoas muscle. The polypropylene mesh lateral to the internal ring was rem(wed but w'as left intact in the area of Hesselbach's triangle. Immediately after the operation the patient noted a marked improvement in his fight groin and thigh pain. Twelve-month follow-up revealed improving residual dysesthetic sensations in his right groin and anterior thigh. His sexual function returned toward normal as his pain improved. Patient 2. A 47-year-old woman presented with left groin pain and a bulge of 1 month's duration. Examination revealed a left femoral hernia and repair was recommended. Laparoscopic hernia repair was performed at her local community hospital. At laparoscopy the femoral hernia was reduced, and a Gore-Tex (W.L. Gore and Associates Inc., Flagstaff, Ariz.) patch was stapled to Cooper's ligament (from the pubic tubercle to the iliac vein), circumferentially around the iliac vessels, and lateral to the vessels. Immediately after laparoscopic herniorrhaphy the patient required a 3-day hospital admission for control of pain in her left groin and anterior thigh. Her pain failed to improve during the next few months, despite oral narcotic analgesics and multiple evaluations by her treating surgeons. The patient presented to The Johns Hopkins Hospital 4 months after laparoscopic herniorrhaphy. Examination revealed no hernia and an ilioinguinal-lateral femoral cutaneous
Surgery Volume 118, Number 5
Sampath et al.
831
T a b l e I. E n t r a p m e n t neuropathies
Genitofemoral
Sensory changes
Posterior abdominal wall, femoral or inguinal region Groin, scrotum, upper thigh Hyperalgesia
Point tendemess
Internal inguinal ring
Hip joint movement
Hyperextension or external rotation of hip increases pain Loss of cremasteric reflex; ejaculatory dysfunction
Common site of entrapment Pain
Associated signs
neuralgia. The patient elected exploration of the previous herniorrhaphy site. Via a transabdominal approach the GoreTex patch was found to extend from the internal ring to the midline, being held in position circumferentially by at least 25 metallic staples. The Gore-Tex patch was completely removed, as were all staples, one of which had pierced the lateral femoral cutaneous nerve. No inguinal or femoral hernias were identified after patch removal. Immediately after the operation the patient noted nearly complete relief of her left groin pain, which had been maintained at 6-month follow-up. She had no evidence of recurrent hernia.
DISCUSSION Injury to s u r r o u n d i n g neural structures d u r i n g traditional inguinal h e r n i o r r h a p h y is a well-recognized complication and is well known to most surgeons. 2' 15 Nerves e n c o u n t e r e d d u r i n g open h e r n i o r r h a p h y are normally protected from injury but sometimes may be severed o r e n t r a p p e d leading to n e u r o m a formation or pain. Neural injury or e n t r a p m e n t after laparoscopic herniorrhaphy has been described, s' 10, 1H.~ with most cases being transient and requiring no specific therapy. However, as illustrated by these two cases a n d described by others, ll'Ls severe nerve injury can accompany laparoscopic inguinal h e r n i a repair, requiring additional surgical intervention for successful management. For example, Eubanks et al. 11 have described five patients with severe groin pain after laparoscopic hernia repair, three of whom required repeat laparoscopy for removal o f staples placed t h r o u g h the lateral femoral cutaneous nerve. The inguinal region, which includes the spermatic cord, inguinal canal, a n d s u r r o u n d i n g subcutaneous tissue, skin, a n d musculoskeletal a n d neurovascular structures, receives sensory innervation e x t e n d i n g from the twelfth thoracic nerve (T12) to the ventral b r a n c h
Ilioinguinal
Femoral
Medial to anterior superior iliac spine
Posterior abdominal wall posterior to inguinal ligament Groin, anterior and medial thigh Hyperalgesia or dysesthesia
Groin, scrotum, flank Hypoalgesia or hyperalgesia Medial to anterior superior iliac spine; anterior abdomen Limitation of internal rotation; extension of hip increases pain Weakness of lower abdominal wall
None
Minimal hip extension increases pain Quadraceps muscle weakness and atrophy; loss of patellar reflex
of the fourth l u m b a r r o o t (L4) (Fig. 1). T h e cutaneous branches o f the l u m b a r plexus include the iliohypogastric, ilioinguinal, femoral, lateral femoral cutaneous, genitofemoral, a n d o b t u r a t o r nerves. In m e n the testes also receive innervation from the spermatic sympathetic plexus. T h e genitofemoral nerve arises from the first a n d second l u m b a r vertebral plexus. It descends dorsal to the parietal p e r i t o n e u m on the surface o f the psoas muscle befbre bifurcating into the genital and femoral branches (Fig. 2). T h e genital branch (external spermatic nerve) traverses the internal inguinal ring to supply the cremaster muscle in m e n and the skin o f the mons pubis a n d labium majus in women. T h e femoral branch (lumboinguinal nerve) o f the g e n i t o f e m o r a l nerve is the cutaneous nerve to the femoral triangle. Inj u r y to this nerve (so-called genitofemorai neuralgia) results in constant b u r n i n g o r sharp pain in the inguinal region (Table I) radiating to the genitalia a n d the medial u p p e r thigh. 16' 17 T h e ilioinguinal nerve is f o r m e d from the first lumb a r nerve. It courses retroperiteoneally before piercing the transversus abdominis muscle near the anterior iliac crest. In stepwise fashion it courses t h r o u g h both the transversus abdominis a n d internal oblique muscles to e m e r g e t h r o u g h the external inguinal ring (Fig. 3). A frequent anatomic variation is an a b e r r a n t sensory trunk that j o i n s with the genital b r a n c h of the genitofemoral nerve. Ilioinguinal e n t r a p m e n t (Table I) has effects similar to those o f genitofemoral neuralgia, with pain a n d b u r n i n g in the inguinal region a n d groin. 18' 19 T h e femoral nerve (L2-L4) traverses the pelvis between the psoas a n d iliacus muscles to course u n d e r the inguinal ligament lateral to the femoral artery. T h e lateral femoral cutaneous nerve (L2-L3) follows a m o r e
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Fig. 3. Illustration depicts position of ilioinguinal nerve as it traverses inguinal canal and exits through external inguinal ring to enter hemiscrotum. In some cases the ilioinguinal nerve may innervate investing structures of the testicle, as shown here. In many cases the terminal branches of the ilioinguinal nerve do not reach the testicle and instead supply the lower groin and upper scrotal area. lateral retroperitoneal path, typically coursing through the inguinal ligament. Injury to either of these nerves can cause pain and associated sensory loss to the lateral upper thigh. ~~ Motor weakness of the quadriceps muscles with loss of the patellar reflex is a hallmark of femoral neuropathy (Table I). It is often difficult to diagnose severe nerve injury after inguinal herniorrhaphy because transient anesthesia or pain in the distribution of one of these nerves is not an u n c o m m o n postoperative occurrence. Because the sensory distribution of nerves in the inguinal region overlaps, a specific entrapment syndrome in a given patient may be difficult to recognize initially. Severe pain (neuralgia) with sensory complaints immediately after operation should alert the surgeon to the possibility of nerve entrapment and, if persistent, should p r o m p t further investigation. Radiographic studies such as pelvic magnetic resonance imaging, percutaneous nerve or facet blocks that alleviate pain at a particular spinal level, or nerve conduction studies may be helpful in determining specific nerve involvement. As laparoscopic herniorrhaphy becomes more popular, the possibility of nerve injuries related to the procedure may increase. Nerve injury may be one of the more c o m m o n (albeit unrecognized) postoperative causes
Surgery November 1995 for patient discomfort and should be an important consideration to the surgeon. There are several reasons for nerve injury during laparoscopic herniorrhaphy. First, the ability to identify and follow the course of a nerve in the operative field may be diminished during laparoscopic repair. The ilioinguinal nerve, for example, may be seen piercing the transversus abdominis muscle, but its passage through the oblique muscles and its relationship to the spermatic cord may not be easy to determine. This may lead to the inadvertent stapling of a prosthetic patch to the nerve. Avoidance of placing deep staples lateral to the internal inguinal ring in the endopelvic fascia may reduce ilioinguinal nerve injury, but the frequent anatomic variation encountered with nerves in this region means that nerve injury is possible even if appropriate care is taken. Second, the laparoscopic surgeon's ability to transpose or divide an encountered nerve to prevent neuroma formation or scarring may be more limited than with open approaches. Further, although laparoscopic reoperation to correct nerve injury has been successful for simple staple removal, 11 it may not be appropriate for all cases. This becomes a specific problem when a nerve is accidentally severed or injured during dissection or hernia repair. U n d e r such circumstances if the nerve does not require repair it is important to separate the free ends of a nerve to avoid subsequent n e u r o m a formation and involvement with the mesh and to sharply divide the nerve as proximal as possible. Nerves encountered during herniorrhaphy that can be sacririced with minimal chance of long-term morbidity include the genitofemoral and ilioinguinal nerves. Injury to the femoral nerve requires repair, because this nerve provides motor input to the muscles of the anterior thigh. Third, the genitofemoral nerve with its course through the internal inguinal ring may be more susceptible to injury via the laparoscopic approach. In patient 1 previously described, the genitofemoral nerve was scarred beneath the mesh and was impossible to dissect free. With the mesh being placed over the internal ring, the genitofemorai nerve may be at risk for compression by the mesh, especially if fibrosis occurs adjacent to the mesh. As with all new procedures a learning curve is associated with laparoscopic herniorrhaphy. Inexperience or lack of knowledge and familiarity of the inguinal anatomy as seen laparoscopically may result in surgical mishaps involving misplacement of prosthetic patches or staples, which can lead to nerve injuries. Furthermore, as experience with laparoscopic hernia repair increases, modifications in repair technique may decrease the risk of nerve injury. For example, it is now considered a mistake by some authorities to place staples dorsal to the iliopubic tract, lateral to Cooper's ligament, in the
Surgery Volume 118, Number 5 so-called z o n e o f d a n g e r , 21' 22 t h u s r e d u c i n g t h e risk o f i n j u r y to t h e iliac a r t e r y a n d vein a n d lateral f e m o r a l cut a n e o u s n e r v e . Also, i m p r o v e m e n t s in l a p a r o s c o p i c e q u i p m e n t m a y r e d u c e t h e risk o f n e r v e injury. M a n y o f t h e c u r r e n t i n t e r n a l s t a p l i n g devices u s e d to a n c h o r mesh in place have deep depths of staple penetration, which can inadvertently injure neural structures. Even in the hands of experienced laparoscopic hernia surgeons, some patients may have nerve injury and a s s o c i a t e d n e u r a l g i a . Early r e o p e r a t i v e n e r v e d e c o m pression in properly selected patients may be the best way to m a n a g e t h e s e difficulties. I n s o m e cases l a p a r o scopic reoperation may provide adequate visualization to allow f o r a s s e s s m e n t o f t h e n e r v e i n j u r y a n d a p p r o priate repair. In other circumstances open transabdominal e x p l o r a t i o n m a y b e n e e d e d . T h e c h a l l e n g e is to i d e n t i f y w h i c h p a t i e n t s h a v e n e r v e i n j u r y t h a t will n o t i m p r o v e w i t h o u t t r e a t m e n t a n d to d i r e c t a p p r o p r i a t e and prompt treatment. We thank Ms. D o n n a Cavi for the original illustrations. REFERENCES
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