Peripheral nerve tumors can occur anywhere in the body. Most of them aren't cancerous (malignant), but they can lead to pain, nerve damage and loss of function in the affected area. Mots peripheral nerve tumors are growths in or near the strands of tissue (axon) that transmit signals from your brain to the rest of your body. However some pelvic bone tumors may also involve the pelvic nerves.
The symptoms and signs of a peripheral nerve tumor develop from direct effects on the main nerve or from the tumor pressing on nearby nerves, blood vessels or tissues. As the tumor grows, it may be more likely to cause signs and symptoms, although tumor size doesn't always determine effects. In case of pelvic nerve tumors, irritation, compression or even destruction of the the sacral plexus or the sciatic nerve will produce pain on the affected nerve's dermatomes, with symptoms such as:
The location of the pain can be highly variable, depending on the nerve(s) affected:
All symptoms usually have something in common: as long as the diagnosis has not been made, the diagnosis remains unknown, the pain is usually labeled as refractory and the treatment is limited to pain control using often disabling medical treatments. If the tumor is not palpable on transvaginal or transrectal examination, MRI will be the first test to evoke a pelvic mass, while confirmation of the nature of the tumor can only be obtained on histopathological examination. Indeed, even if the vast majority of these tumors are benign, the possibility of a malignant tumor should never be ruled out. The MRI examination is therefore essential, but also the neuropelveological examination is very useful: tumor size, duration of symptoms and presence of sensory disturbance possesses little value in differential diagnosis whether the tumor is benign or malignant, but severe motor weakness confirmed by neuropelveological examination is of great diagnostic importance and of high suspicion for malignancy.
In case of isolated tumors of the pelvic nerves, simple resection is usually sufficient. In bone tumors of the pelvis reaching the pelvic nerves (tumor of the pelvic bone or of the sacrum..), however, resection requires tumor free margins, which implies a large and en bloc resection of the bone and the affected nerves.
At the Possover International Medical Center, our management is based on laparoscopic exploration of the pelvis with resection of the tumor. The procedure is performed under general anesthesia avoiding drugs that reduce muscle contractility in the administration of anesthesia. The interventions is usually started by opening the retroperitoneal space and exposure of all vessels surrounding the tumor.
It is well known that radical pelvic surgery can be accompanied by postoperative morbidity. This functional urinary and intestinal tracts morbidity varies, depending on the approach to the pelvis. The perineal or perianal surgical approach causes functional morbidity problems with bladder or rectum continence; the abdominal approach causes problems with hypercontinent bladder retention, chronic constipation, or both.
For this reason, nerve-sparing techniques were developed in different speciality areas and consist mainly of identifying and respecting, as far as possible, the different nerves during resection of anatomical structures. Because of the magnification effect and the possibility of blood-free dissection, even in the depth of the pelvis, laparoscopic surgery became one of the most useful and important instruments in learning the pelvic retroperitoneal anatomy. The combination of a good knowledge of pelvic neuroanatomy and the technique of laparoscopic dissection of the pelvic nerves aided by the magnification of the endoscope allows a very gentle dissection of all structures deep into the pelvis. To gain intraoperative information about the motoric function of the exposed nerves, we developed for many years the technique of laparoscopic neuronavigation, also called the LANN technique. Using anodin electrical stimulation of the nerves, the surgeon is able to gain direct information on the functionality of all exposed nerves making this way intraoperative an individual functional cartography of the all pelvic nerves in each patient. While the sciatic nerve – the biggest nerve of the entire body - is easy to be identified, identification of the different sacral nerves root is not always that easy. In case of doubt, differentiation of the pelvic nerves is obtained by intraoperative electrical stimulation with a laparoscopic probe. While s #4 stimulation does not produce any motor reaction in the lower extremities, stimulation of Sacral Nerve Root #3 is confirmed visually by a deepening and flattening of the buttock groove as well as a plantar flexion of the large toe and to a lesser extent of the smaller toes. Stimulation of Sacral Nerve Root #2 produces an outward rotation of the leg and plantar flexion of the foot as well as a clamp-like squeeze of the anal sphincter from anterior/posterior. Stimulation of Sacral Nerve Root #1 induces a motion of the leg with interne rotation while stimulation of the lumbal root #5 induces a flexion/extension of the foot. Stimulation of the obturator nerve induces an adduction of the leg, while stimulation of the femoral nerve induces an extension of the knee.
Possover M. "Laparoscopic exposure and electrostimulation of the somatic and autonomous pelvic nerves: a new method for implantation of neuroprosthesis in paralysed patients?" J Gynecol Surg – Endoscopy, Imaging, and Allied Techniques 2004;1:87–90
Possover M et al "The Laparoscopic Neuro-Navigation“ - LANN: from a functionnal cartography of the pelvic autonomous neurosystem to a new field of laparoscopic surgery. Min Invas Ther & Allied Technol, 2004;13: 362-367.
Possover M et al. "Anatomy of the sacral roots and the pelvic splanchnic nerves in women using the LANN technique". Surg Lap Endosc Percutan Tech, 2007; 17: 508-510.
Because the laparoscopic approach allows a sufficient and necessary magnification to make microsurgery of the nerves possible, laparoscopy enables the integrity of the nerves to be respected as much as possible. With an open abdomen, because it is not possible to see these nerves placed so profound in the pelvis behind the pelvic vessels, laparotomy does not allow such precision in the dissection of the nerves. Similarly, the rear approach is far too destructive because it requires the resection of a part of the sacral bone.
The laparoscopic exploration not only permits resection with tumor-free margins of the lesions, but also histological confirmations. Primary exposure of the rectum, the ureter and the pelvic nerves make the procedure safe and much easier than classical neurosurgical approaches, and with less risk for postoperative functional morbidities. All vessels surrounding the tumor have to be secured. Primary exposure of the pelvic artery - the internal iliac artery - is strongly recommended, so that in case of hemorrhage, this artery can be directly closed (temporarily or permanently) in order to make bleeding control easier and faster. In case of young women, because desire of pregnancy, the vessels of the uterus have to preserved as much as possible.
Because schwannomas are as their name suggests, a tumor of the Schwann sheath of the nerves, as long as the tumor is benign, the enucleation of the tumor with preservation of the nerves themselves - and therefore with preservation as much as possible the functional integrity of the nerve - can be obtained by laparoscopy. For this purpose, the surgeon must make maximum use of the magnification effect of the endoscope, in order to be able to follow the rules of micro-neurosurgery. Because schwannoma can be malignant tumors, the tumor is dissected keeping the capsules intact and morcellated only within an endobag avoiding strictly any contamination of the abdominal cavity.
Nevertheless, this surgery is not easy. It requires a lot of experience in laparoscopic surgery of pelvic nerves - ISoN-level 3 certified neuropelveologist- within particular an absolute knowledge of the anatomy of pelvic nerves to avoid surgical lesions of them, as well as an absolute knowledge of the anatomy of pelvic vessels to avoid bleeding during the operation. The surgeon must remain calm throughout the operation and dissect the tumor as if it was cancer, i.e. with as little contact with the tumor as possible in order to avoid at all costs a rupture of the capsule with possible spread of tumor cells in the pelvic cavity. The resection of the tumor must be complete in order to avoid a recurrence.
Possover M. "Laparoscopic management of sacral nerve root schwannoma with intractable vulvococcygodynia: report of three cases and review of literature". J Minim Invasive Gynecol. 2013 May-Jun;20(3):394-7.
Operative treatment of tumors in the sacroiliac area is among the most challenging muscloskeletal tumor surgeries. Because almost all the deaths from chondromas result from local recurrence, greater effort to obtain adequate surgical excision has been made over the last decades. Most used common surgical approaches are the posterior, posterolateral, anterior and posterior, anterior and lateral combined approach. The anterior and lateral combined approach is used in the resection of large iliac tumors, and the abdominoinguinal approach is selected for large retroperitoneal tumors. In tumor of the sacrum, exposition is mostly obtained by a posterior midline incision; lateral osteotomies are usually performed through the sacralforamina using a threadwire saw and Kerrison rongeurs. Although various reports analyzed "en-bloc" excision of sacral tumors, there are still technical problems to improve protection of nerve roots, preserve surrounding structures and reduce intraoperative bleeding, maintaining the oncologic result. In posterior approach, because first elevation of the sacrum allows dissection of presacral structures, risk for damages intrapelvic structures is high. Wound infections, neurologic deficits, pelvic instability, and cerebrospinal fluid leakage are the main complications of sacrectomy. Among these complications, extensive hemorrhage is the most serious complication since it may threaten the life of the patient and jeopardize the outcome of surgery. Angelini reported about sacral resection by posterior approach with a mean blood loss by 2961 ml (range; 1000 to 8000 ml) . In a further retrospective study on 173 patients who underwent sacral tumor resection, sixty-nine (39.88%) patients had blood loss greater than 3000 ml. It is obvious that primary control on blood supply of the sacrum and of the parametries may reduce such intraoperative blood loss. The results of several studies suggest preoperative arterial embolization and aortic balloon occlusion. However, indications for performing embolization still remain uncertain. Because of numerous anastomoses between the sacral (medial and lateral), gluteal (inferior and superior) and pudendal vessels, single closure of the internal iliac artery does not protect from hemorrhage. We opted for a primary closure of all parametric vessels including the internal iliac artery, the gluteal and the sacral vessels by laparoscopy before starting with bone resection. Open surgery should have had expose the patient for a greater and unnecessary morbidity. In contrary, control of the pelvic blood supply by laparoscopy do not present major difficulties for pelvic surgeons trained in laparoscopic retroperitoneal surgery. In our patient, primary laparoscopic closure of the pelvic blood supply decrease considerably blood loss despite the massive postgravid pelvic varicosis.
Primary laparoscopic dissection of the ureter and of the bowel had not only protected the patient from severe visceral complications, but also had permitted an adequate exploration of the pelvis for possible retroperitoneal, intraabdominal or even visceral tumor infiltration. The laparoscopic dissection of the tissue surrounding the tumor permits a precise selection of the level of sacral resection with macroscopic tumor-free margins. The introduction of the Gigly saw through the different sacral foramens had also contributed to a precise transaction of the bone under laparoscopic control.
Pelvic bone amputation may also result in pelvic nerves damages. High amputation of the sacrum inevitably results in damages of the sacral nerve roots, the pudendal nerve and the coccygeal plexus. It is well-known that simultaneous abdominosacral resection circumvents many of problems for such advanced procedures since it provides good exposure of the intraabdominal structures, and avoids damage to the sacral nerve roots. Laparoscopic exposure of the sacral plexus and other pelvic somatic nerves, enabled the exploration of their relation to the tumor that had a direct impact on the radicality of the procedure. Laparoscopic dissection of the femoral nerve before psoas muscle resection permit preservation of locomotion while preservation of the sacral nerves roots S3/4 reduce risk for bladder and rectum dysfunctions.
Possover M, Uehlinger K, Exner U. "Laparoscopic assisted resection of a ilio-sacral chondrosarcoma: A single case report".Int J Surg Case Rep. 2014;5(7):381-4.
Vulvodynia is a chronic pain syndrome affecting ...