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Endometriosis of the Sciatic Nerve

Laparoscopic Treatment of Endometriosis of the Sciatic Nerve

Introduction

Deep infiltrating endometriosis is usually associated with a number of different symptoms and presents a complex treatment challenge.

It is well known that the urinary and intestinal tracts can be affected by endometriosis. However, it is less commonly known that endometriosis can affect the pelvic and sciatic nerve. These and other clinical forms of endometriosis are thought to be very rare. Likewise, a low incidence of other pelvic nerve disorders is reported in the literature. Although endometriosis is one of the most common gynecological disorders affecting millions of women around the world, case reports of sciatic nerve endometriosis are rarely found in the literature.

In 2004, Professor Marc Possover started to draw the attention of his colleagues in the fields of neurology, neurosurgery, orthopedic medicine and pain management to the problem of sciatic nerve endometriosis (because patients normally do not consult a gynecologist for treatment of sciatic nerve pain). Possover had observed an increase in the number of women coming to his department seeking help for suspected endometriosis of the sciatic nerve. Whenever a woman presents with sciatic nerve pain of unclear origin, endometriosis should always be considered as the potential cause, especially if the pain worsens during the menstrual cycle.

Since endometriosis of the sciatic nerve may occur as an isolated entity, the diagnosis of sciatic nerve endometriosis cannot be excluded based on negative magnetic resonance imaging (MRI), computed tomography (CT), vaginal examination and ultrasound findings or even negative pelvic laparoscopy findings. Laparoscopic examination of the sciatic nerve is needed to establish the diagnosis. If suspicion of sciatic nerve endometriosis is confirmed, surgery must be performed for endometriosis removal and nerve relief.

In 2011, Professor Possover reported treating more than 200 cases of endometriosis of the sciatic nerve. It is therefore assumed that this disease is not as rare as previously thought. Moreover, endometriosis can affect all other nerves of the pelvis, including the obturator and femoral nerves.

There are several reasons why the diagnosis of pelvic nerve endometriosis – and other pelvic nerve disorders – is frequently neglected. One is the difficulty in diagnosing such pelvic conditions. Because the laparoscopic surgeon must have a sound knowledge of the complex anatomy of the pelvis – especially of the pelvic nerves – and a great deal of skill and experience in surgery, laparoscopic treatment of endometriosis of the sciatic nerve is the most demanding type of pelvic surgery.

Another major reason for the underdiagnosis of endometriosis of the sciatic nerve is a lack of awareness of the disease. A study published by Professor Possover in 2011 showed that patients with endometriosis of the sciatic nerve had to undergo an average of four surgeries before the correct diagnosis was ultimately established – at a delay of several years.

Moreover, the knowledge and expertise needed for the diagnosis and treatment of endometriosis of the sciatic nerve is spread among different medical disciplines, whose specialists normally do not interact with each other. Endometriosis is typically a gynecological disease, the pelvic nerves are frequently ignored by all medical specialties, the diagnosis of diseases of the nervous system is left up to neurologists, and the treatment of nerve disorders is often reserved to neurosurgeons. Although laparoscopic surgery is the treatment method of choice, neurosurgeons generally do not learn how to perform laparoscopic surgery in medical school, and they generally are not familiar with the anatomy of the pelvis. This is a real dilemma!

Types of endometriosis of the sciatic nerve

There are two basic types of endometriosis of the sciatic nerve: deep infiltrating endometriosis of the rectovaginal septum (space between the rectum and vagina) with involvement of the parametrium (connective tissues on the cervix) and sciatic nerve, and isolated endometriosis of the sciatic nerve.

Deep infiltrating endometriosis with parametrial and sciatic nerve involvement

Deep infiltrating endometriosis of the rectovaginal septum with or without rectal or parametrial involvement can also affect the sciatic nerve roots (sacral nerve roots) or nerves. The second (S2), third (S3) and fourth (S4) sacral nerves may also be involved due to the close proximity of these anatomical structures.

Involvement of the first sacral nerve (S1) is extremely rare, and the fifth lumbar nerve (L5) is almost never involved. Because of the anatomical situation, the condition results in pain in the areas innervated by the aforementioned sacral nerves, i.e., in the genital area (vulvar and pubic pain), coccygeal area (tailbone pain), and the buttocks and/or back of the thigh (sciatica).

Since the S3 and S4 sacral nerves are involved in bladder, bowel and sexual functions, common symptoms include frequent urination (more than 8 times per day), nighttime urination (nocturia), loss of libido and chronic constipation. If the endometriosis damages the nerves responsible for urinary function, urinary retention (inability to urinate) may occur, but is extremely rare. Motor deficits are unlikely to occur. Because of the intimate anatomical relationship between these nerves and the ureters, ureteral involvement is also possible. Preoperative ultrasound assessment of the kidneys is therefore essential.

Isolated endometriosis of the sciatic nerve

As the name implies, this type of endometriosis only affects the sciatic nerve. The cause of the disease is still unknown. Like endometriosis of the bladder and bowel, isolated endometriosis of the sciatic nerve is a highly destructive disease that infiltrates and destroys the affected tissues. Laparoscopic surgery is therefore essential and should be performed as quickly as possible before the nerve damage becomes irreversible.

Laparoscopy is indicated, even if there is only clinical suspicion of isolated sciatic nerve endometriosis. Hormone therapy is unhelpful and perhaps even hazardous because it can result in delayed surgical management of the disease. Endometriosis of the sciatic nerve almost always involves the upper (proximal) part of the sciatic nerve, which merges with L5 lumbar nerve fibers and the S1 and S2 sacral nerve fibers.

Damage to these nerves can lead to motor deficits and may particularly affect movements that involve lifting and lowering of the foot. Bladder or bowel dysfunction rarely develops because most of the nerves that innervate the bladder and rectum contain fibers from the S3 and S4 sacral nerve roots. Nerve pain occurs mainly on the back of the leg, but may also occur on the front of the lower leg. Numbness, sensory disturbances and even a total loss of sensation may occur, depending on the extent of sciatic nerve damage.

Die Therapie dieser Form der Endometriose kann nur in Zentren durchgeführt werden, die sich auf die anspruchsvolle Endometriose-Chirurgie spezialisiert haben. Der Operateur muss sowohl in der Diagnostik als auch der chirurgischen Therapie der Neuropelveologie ausgebildet sein. Die Operation basiert auf der laparoskopischen Darstellung und Entlastung des Nerven, bei der befallene/zerstörte Nervenanteile und alle Endometrioseherde komplett entfernt werden, um einen Rückfall zu verhindern. Ein operativer Eingriff durch den Darm, den Neurochirurgen vorschlagen, bietet keinen ausreichenden Zugang zum Ischiasnerven, und die Endometriose lässt sich nicht vollständig entfernen, da sie sich innerhalb des Beckens und nicht ausserhalb entwickelt. Durch eine Standard-Laparoskopie des kleinen Beckens ohne die direkte Untersuchung des Nerven lässt sich die isolierte Form der Endometriose des Ischiasnerven ebenfalls nicht diagnostizieren.

Isolated endometriosis of the sciatic nerve can only be treated at medical centers specialized in the challenging field of endometriosis surgery. The surgeon must be specifically trained in the diagnosis and surgical management of pelvic nerve disorders. Surgical treatment consists of laparoscopic nerve exposure and neurolysis. All damaged and infiltrated nerve segments and endometriosis implants are removed to prevent recurrence. The intestinal access route proposed by neurosurgeons does not provide sufficient access to the sciatic nerve or a means of complete endometriosis removal because endometriosis develops inside, not outside, the pelvis. Likewise, isolated endometriosis of the sciatic nerve cannot be diagnosed by standard laparoscopy of the minor pelvis without a direct nerve examination.
Thus, laparoscopic surgery is absolutely essential and should be performed as soon as possible to prevent irreversible damage to the sciatic nerve.

Facts and figures

How much blood is lost? < 50 ml, but there is a permanent risk of bleeding.
Is blood transfusion needed? No.
How long does the surgery take? 2 to 4 hours.
Is intensive-care monitoring needed after surgery? No.

How many incisions are made? Three 5 mm incisions in the lower abdominal region.
How long is the hospital stay? 3 to 5 days.
How long until normal activities can be resumed? 3 weeks.
Is there a risk of paralysis? 

No.
Do the sensory deficits disappear? Usually not, but nerve growth may occur in the 
following months or years.

References

Possover M, Henle KP, Schneider T. Laparoscopic therapy for endometriosis and vascular entrapment of sacral plexus. Fertil Steril 2011; 95(2): 756-8.

Possover M. New surgical evolutions in management of sacral radiculopathies. Surg Technol Int 2010; 19: 123-8.

Possover M., Baekelandt J, Flaskamp C, Li D, Chiantera V. Laparoscopic neurolysis of the sacral plexus and the sciatic nerve for extensive endometriosis of the pelvic wall. Minim Invasive Neurosurg 2007; 50: 33-36.

Possover M, Chiantera V. Isolated infiltrative endometriosis of the sciatic nerve: about three cases. Fertil Steril 2007; 87: 417-9.

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