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At least 199 records · Page 11Linked to original sources
PubMed1985

The human posterior tibial somatosensory evoked potential: synapse dependent and synapse independent spinal components.

Evidence has been obtained for the existence of two separate events occurring in the human spinal cord following posterior tibial nerve (PTN) stimulation. These events can be recorded on the surface in unanesthetized individuals. The first is an ascending wave which is conducted up to the cord at constant velocity and has a relatively short refractory period consistent with a compound nerve action potential. This represents the afferent volley traversing the lumbosacral plexus and the ascending dorsal columns. A second event, the N22/P22 complex, is surface negative on the back and surface positive anteriorly; its amplitude is maximal 5-15 cm above the level of the L4 spine and its peak latency remains constant at all levels. This activity has a relatively long refractory period. These characteristics of N22/P22 indicate that it is a localized synaptically dependent event conforming to a transverse dipole with dorsal negativity and a simultaneous anterior positivity. The N22/P22 is probably generated in the dorsal grey at the root entry zone. The N22/P22 is analogous to the stationary N13/P13 recorded over the neck following median nerve stimulation.

Adult↗
PubMed1985

Tolerance of peripheral nerve to intraoperative radiotherapy (IORT): clinical and experimental studies.

In our clinical experience combining wide excision and intraoperative radiotherapy (IORT), five patients have developed clinical signs of lumbosacral or sciatic neuropathy within 9 months of receiving IORT to a dose of 20-25 Gy. Three patients showed recovery of nerve function over several months while two patients have shown no recovery and have near complete loss of extremity function. In an attempt to investigate this clinical observation further, the lumbosacral plexus and sciatic nerve of American foxhounds were surgically exposed and received a single dose of IORT ranging from 20-75 Gy. An approximate linear relationship between radiation dose and time to onset of hind limb paresis is found with 19 of 21 irradiated dogs showing clinical signs of nerve injury within an interval of 1-19 months. No recovery of nerve function is seen in these dogs. Histological study of the irradiated nerves demonstrates a loss of nerve fibers, particularly those of the large myelinated type without evidence of vascular occlusion or thrombosis. These studies suggest that peripheral nerve may be a dose-limiting normal tissue in clinical studies of IORT.

Adult↗
PubMed1995

Clinical toxicity of peripheral nerve to intraoperative radiotherapy in a canine model.

PURPOSE: The clinical late effects of intraoperative radiotherapy (IORT) on peripheral nerve were investigated in a foxhound model. METHODS AND MATERIALS: Between 1982 and 1987, 40 animals underwent laparotomy with intraoperative radiotherapy of doses from 0-75 Gy administered to the right lumbosacral plexus. Subsequently, all animals were monitored closely and sacrificed to assess clinical effects to peripheral nerve. This analysis reports final clinical results of all animals, with follow-up to 5 years. RESULTS: All animals treated with > or = 25 Gy developed ipsilateral neuropathy. An inverse relationship was noted between intraoperative radiotherapy dose and time to neuropathy, with an effective dose for 50% paralysis (ED50) of 17.2 Gy. One of the animals treated with 15 Gy IORT developed paralysis, after a much longer latency than the other animals. CONCLUSIONS: Doses of 15 Gy delivered intraoperatively may be accompanied by peripheral neuropathy with long-term follow-up. This threshold is less than that reported with shorter follow-up. The value of ED50 determined here is in keeping with data from other animal trials, and from clinical trials in humans.

Animals↗
PubMed2004

Testicular pain after inguinal hernia repair: an approach to resection of the genital branch of genitofemoral nerve.

BACKGROUND: The neuropathic groin pain after inguinal hernia repair is usually due to a neuroma of the ilioinguinal, iliohypogastric, or genitofemoral nerve. When the postherniorrhaphy pain symptoms include mostly testicular pain, then the genital branch of the genitofemoral nerve comes first in the differential diagnosis. Nerve blocks are helpful in determining which of the three nerves is implicated in the pain syndrome. Although the surgical approach to the ilioinguinal nerve is now well established, it has been difficult to identify the genitofemoral reliably enough to permit resection of this nerve. STUDY DESIGN: Anatomic cadaver dissections of nerves exiting the lumbosacral plexus were performed. Their course was followed to their final terminations. Based on these findings, an operative approach was designed to address the involved nerve at a specific site. The results and outcomes were prospectively followed. RESULTS: The present anatomic study identifies the site within the inguinal canal where the genital branch of the genitofemoral nerve may be identified. The designed operative approach points to the proximal site of the canal to be opened for an exposure. It also dictates that the nerve should be dissected and resected proximal to the surgical repair or mesh reconstruction, which allows its retroperitoneal placement. All four patients were relieved of their preoperative symptoms using this approach. CONCLUSIONS: Severe and chronic testicular pain after inguinal hernia repair can be treated by a designed approach that identifies the genital branch of the genitofemoral nerve in the proximal inguinal canal, its resection point proximal to the previous operative field, and placement behind the peritoneum.

Aged↗
PubMed2005

Intravenous immunoglobulin therapy for idiopathic postoperative lumbosacral plexopathy.

We report a patient who developed an acute lumbosacral plexopathy (LSP) following spinal surgery on lumbos segments. He recovered dramatically following treatment with high-dose intravenous immunoglobulin (IVIg). A 66-year-old man who underwent an L4 to S1 decompressive laminectomy required re-admission after developing contralateral leg pain. Follow-up lumbosacral magnetic resonance imaging showed only mild postoperative changes. Ten days after re-admission, he developed relatively rapid onset ipsilateral inguinal pain and weakness of all his leg muscles with diminished sensation in a lumbosacral plexus distribution. Re-exploration revealed no specific lesion except for adhesions and resulted in no improvement. Following treatment with IVIg (0.4 g/kg daily) for five days, he showed dramatic resolution of motor weakness and pain. There has been no relapse following six months follow-up. Although IVIg treatment does not guarantee a positive response in all types of LSP, it should be considered for severe, rapidly progressive and even for postoperative cases.

Aged↗
PubMed2004

Unilateral lower extremity paralysis after coil embolization of an internal iliac artery aneurysm.

Neurologic complications after treatment of internal iliac artery (IIA) aneurysms are rare, especially if confined to one IIA. We report a patient in whom profound right lower extremity paresis developed after unilateral right IIA coil embolization for treatment of a 4-cm IIA aneurysm, despite the presence of a patent contralateral IIA. This case illustrates the important, yet unpredictable, nature of pelvic blood flow to the distal spinal cord and lumbosacral plexus and the unpredictable consequence of IIA occlusion.

Aged↗
PubMed2004

Stem cell transplantation and other novel techniques for promoting recovery from spinal cord injury.

A number of potential approaches aim to optimize functional recovery after spinal cord injury. They include minimizing the progression of secondary injury, manipulating the neuroinhibitory environment of the spinal cord, replacing lost tissue with transplanted cells or peripheral nerve grafts, remyelinating denuded axons, and maximizing the intrinsic regenerative potential of endogenous progenitor cells. We review the application of stem cell transplantation to the spinal cord, emphasizing the use of embryonic stem cells for remyelinating damaged axons. We speculate that harnessing the potential of endogenously born stem cells already present in the spinal cord represents an important therapeutic target. We also discuss the potential application of peripheral nervous system reconstruction to recovery from spinal cord injury. The principles of peripheral nerve regeneration and concepts of nerve grafting are reviewed. Particular attention is given to peripheral nerve allotransplantation for repairing extensively injured tissue when autologous donor nerve material is scarce. The potential role of nerve transfers for reconstructing the injured spinal cord, particularly the cauda equina and lumbosacral plexus, are also described.

Animals↗
PubMed2006

Strain and excursion of the sciatic nerve in the dog: biomechanical considerations in the development of a clinical test for increased neural mechanosensitivity.

Analysis of human nerve biomechanics has contributed to the validation of clinical tests to diagnose back pain of neural origin. Equivalent clinical tests for dogs would be valuable to differentially diagnose lumbosacral pain. To develop such a test, the increase in strain in the sciatic nerve of dogs and the longitudinal excursion of the nerve in relation to its surrounding structures during hind limb movements were evaluated. A miniature strain gauge was inserted into the sciatic nerve in seven canine cadavers and excursion was measured using a digital calliper. A cumulative increase in strain of 7.2% (+/-2.8%) was observed for the combined movements of hip flexion, stifle extension, hock flexion and digit extension (P<0.0001). Although all components contributed significantly to the increase (P=0.03), the sciatic nerve demonstrated a curvilinear response to increased loading. A 10.0+/-1.0mm excursion was recorded with stifle extension (P=0.002). It was concluded that, the sciatic nerve in dogs accommodates to joint movements by stretching and gliding. This biomechanical analysis has contributed to the development of a clinical test equivalent to the human straight leg raise to evaluate increased mechanosensitivity of the lumbosacral plexus.

Animals↗
PubMed1992

The lithotomy position in colon surgery. Postoperative complications.

The modified lithotomy position frequently is used in general surgery because it gives excellent simultaneous access to the abdomen and perineum. There are a variety of complications that may occur including lumbosacral plexus stretch, sciatic and peroneal nerve injury, and compartment syndrome of the legs. Through preoperative nursing assessment of a patient's age, nutritional status, skin condition, pre-existing disease state, and anticipated type and length of surgical procedure, patients at risk for developing postoperative complications may be identified. The perioperative nurse's role is to use this knowledge to assist the surgical team in safe patient positioning and optimal intraoperative care.

Adolescent↗
PubMed1990

Selected neurologic complications of pregnancy.

Many neurologic disorders, such as eclampsia, pseudotumor cerebri, stroke, obstetric nerve palsies, subarachnoid hemorrhage, pituitary tumors, and choriocarcinoma, can develop in the pregnant patient. Maternal mortality from eclampsia, which ranges from 0 to 14%, can be due to intracerebral hemorrhage, pulmonary edema, disseminated intravascular coagulation, abruptio placentae, or failure of the liver or kidneys. Associated fetal mortality ranges from 10 to 28% and is directly related to decreased placental perfusion. Pseudotumor cerebri can be associated with serious visual complications; thus, the therapeutic goal is to prevent loss of vision. The risk of stroke in the pregnant patient is 13 times the risk in the nonpregnant patient of the same age. The major causes of stroke in pregnant patients are arterial occlusion and cerebral venous thrombosis. Lumbar disk prolapse is common in pregnant patients, and lumbosacral plexus injuries can occur during labor or delivery. In addition, peripheral nerve compression or entrapment syndromes are thought to be caused by the retention of fluid during pregnancy. The incidence of subarachnoid hemorrhage during pregnancy is 1 in every 10,000 patients, a rate 5 times higher than in nonpregnant women. Because of a proliferation of prolactin-secreting cells, the pituitary gland can enlarge dramatically during pregnancy, a change that can disclose a previously unknown tumor or cause a known pituitary tumor to become symptomatic. The incidence of choriocarcinoma is 1 in 50,000 full-term pregnancies but 1 in 30 molar pregnancies. This malignant tumor has a high rate of cerebral metastatic lesions. In addition to these disorders that develop during pregnancy, the pregnant state can affect numerous preexisting neurologic conditions, including epilepsy, headaches, multiple sclerosis, myasthenia gravis, spinal cord injury, and brain tumors. We discuss advice for patients with such conditions who wish to become pregnant, recommendations for medical and surgical management, and surgical considerations for neurologic complications during pregnancy.

Female↗
PubMed2003

Evidence for asymmetric distribution of sciatic nerve endometriosis.

OBJECTIVE: To investigate if a lateral asymmetry exists in the distribution of endometriotic lesions of the sciatic nerve. DATA SOURCES: All articles on sciatic nerve endometriosis identified by MEDLINE and EMBASE database searches were retrieved, and additional reports were collected by systematically reviewing all references. Monographs on endometriosis published in the last 15 years were consulted. METHODS OF STUDY SELECTION: We considered articles in which the presence of an endometriotic lesion of the sciatic nerve and the affected side were assessed. We also included reports lacking histological examination of sciatic nerve specimens but with a surgical diagnosis of pelvic endometriosis. Two authors abstracted data independently on standardized forms. The number of women and the side of the lesion were obtained from individual studies, and the combined frequency of left- and right-side sciatic nerve endometriosis in published reports was computed. TABULATION, INTEGRATION, AND RESULTS: Thirty-two reports including 63 subjects were selected. Endometriosis of the sciatic nerve was on the right side in 41 patients, on the left in 20, and bilateral in two. Considering only patients with unilateral sciatic nerve endometriosis, the observed proportion of right-side lesions (41 of 61 [67.2%]; 95% confidence interval 54.0%, 78.7%) significantly differed from the expected proportion of 50% (chi(2)(1) 7.23, P =.007). Among the 16 cases of histological demonstration of endometriosis infiltrating sciatic nerve roots or fibers, ten had it on the right side (62.5%) and six on the left. Twenty-six of the 38 subjects (68.4%) with surgical demonstration of pelvic endometriosis but without histopathologic evidence of direct sciatic nerve involvement were affected by right cyclic sciatica. CONCLUSION: The finding that two thirds of patients with sciatic nerve endometriosis had right-side lesions constitutes further evidence against the coelomic metaplasia theory. The interposition of the sigmoid colon between the regurgitated endometrial cells implanted on the left posterolateral pelvic peritoneum seems to protect the left lumbosacral plexus and sciatic nerve.

Adolescent↗
PubMed2003

Laterally extended endopelvic resection. Novel surgical treatment of locally recurrent cervical carcinoma involving the pelvic side wall.

OBJECTIVES: To demonstrate the therapeutic potential of the laterally extended endopelvic resection (LEER) especially for patients with recurrent cervical carcinomas involving the side wall of an irradiated pelvis. These patients, suffering from the most common situation of local failure, have so far no longer been considered for curative therapy. METHODS: Extending the lateral resection plane of pelvic exenteration to the medial aspects of the lumbosacral plexus, sacrospinous ligament, acetabulum, and obturator membrane enables the complete removal of a subset of locally advanced and recurrent tumors of the lower female genital tract fixed to the pelvic wall with free margins (R0). Patients selected for LEER were accrued to a prospective outcome trial. RESULTS: Thirty-six patients with recurrent (n = 29) or primary advanced (n = 7) gynecologic malignancies involving the side wall of the lesser pelvis underwent LEER from July 1996 until October 2002. The majority of the patients suffered from cervical carcinoma (n = 29) and had received previous pelvic irradiation (n = 24). Tumor-free (R0) lateral margins were obtained in 34 patients. Severe postoperative complications occurred in 14 patients with one treatment-related death. Five-year survival probability is 49% for the whole group and 46% for those patients considered only for palliation with current treatment options. Most patients without evidence of disease at least 1 year after LEER achieved good quality of life. CONCLUSIONS: LEER can be offered as novel surgical salvage therapy to a selected subset of patients with locally advanced and recurrent cervical carcinoma involving the pelvic wall.

Adult↗
PubMed2005

[Imaging features of neurofibromatosis type 1].

Neurofibromatosis type 1 (NF1) is the most common of all the phakomatoses. It is an autosomal dominant disorder, with about 50% of patients being new mutations. NF1 is diagnosed based on the presence of well established diagnostic criteria. Prominent cutaneous manifestations include cafe-au-lait spots, freckling and cutaneous neurofibromas. CNS lesions are frequent and imaging is valuable for diagnosis, treatment and follow-up of patients. Tumors of the central nervous system are frequent. Optic nerve glioma usually affects younger patients with clinical symptoms in one third of cases. MRI shows fusiform enlargement with variable enhancement of the optic nerve. These tumors are usually non-aggressive with good prognosis. Other gliomas and astrocytomas can occur as well, usually midline in location, that also generally have good prognosis. Non-tumoral white matter lesions, referred as unidentified bright objects or UBO's, are frequently observed, typically in the basal ganglia and posterior fossa structures. These lesions are usually seen during childhood and they typically diminish with age. The distinction between UBO's and other tumors may be difficult to achieve at imaging, and a malignant evolution may very rarely be observed. Patients with NF1 may have hydrocephalus and dural sac anomalies leading to meningocele formation. Neurofibromas and plexiform neurofibromas involve peripheral nerves and nerve sheaths. Plexiform neurofibromas may cause radicular symptoms. They more frequently involve the lumbosacral plexus. Neurofibromas are homogeneous oval shaped tumors that may extend into the spinal canal. Neurofibrosarcoma is the main cause of death of NF1 patients less than 40 years of age. It may develop de novo or from sarcomatous degeneration of a pre-existing plexiform neurofibroma. It should be suspected in patients with new onset of symptoms or patients with changing symptoms. At imaging, it is characterized by a large heterogeneous tumor invading adjacent structures. Osseous lesions have been described including progressive thoracic scoliosis, vertebral anomalies (posterior scalloping is very suggestive), long bones anomalies with frequent bowing of the tibia, sometimes resulting in pseudarthrosis, and rib anomalies with ribbon ribs. Vascular lesions may occur resulting in arterial hypertension and aneurysm formation.

Bone Neoplasms↗
PubMed1997

Mapping of tibial nerve evoked magnetic fields over the lower spine.

Using a low-noise 49-channel dc-SQUID system spinal somatosensory evoked fields (SEF) were recorded which were generated by compound action currents evoked upon posterior tibial nerve stimulation. The SEF mapping showed the action current propagation along the sciatic nerve, lumbosacral plexus and cauda equina in parallel to simultaneously recorded electrical potentials (SEP). For a reliable intraindividual side-to-side comparison of spinal SEFs the right and left tibial nerves were stimulated in alternating order; this procedure minimizes artifactual inter-nerve SEF map differences due to eventual patient-to-sensor displacements which might occur in serial measurements. These large-area lumbar SEF mappings open up several clinical perspectives for magnetoneurography, in particular with respect to the 3D-localization of proximal conduction blocks.

Adult↗
PubMed1999

Sacral spinal cord neurons responsive to bladder pelvic and perineal inputs in cats.

In chloralose-anesthetized or decerebrate male cats, 70% of 73 sacral spinal cord neurons activated from the bladder branch of the pelvic nerve also received excitatory inputs from urethra and/or perineal cutaneous nerves (sensory pudendal in 55% and superficial perineal in 84% of neurons). Only 29% of these neurons were excited by the hindlimb skin and muscle nerves tested. The pelvic nerve-responsive neurons received monosynaptic urethral/perineal input in 25% of cases and required temporal summation of this input in 47% of cases. Of 211 neurons responding to superficial perineal nerve stimulation, 101 were not excited by the other nerves tested. Neurons activated by superficial perineal nerve stimulation were found predominantly in S2. It is likely that the superficial perineal nerve represents an important pathway whereby perineal stimulation influences bladder function.

Animals↗
PubMed2002

Spatial segregation within the sacral parasympathetic nucleus of neurons innervating the bladder or the penis of the rat as revealed by three-dimensional reconstruction.

The purpose of the present investigations was (1) to examine the spatial organization of preganglionic neurons of the sacral parasympathetic nucleus in the lumbosacral spinal cord of male adult rats and (2) to search, in this nucleus, for a possible segregation of sub-populations of neurons innervating the penis or the bladder, respectively. To estimate their spatial organization, neurons of the sacral parasympathetic nucleus were retrogradely labeled by wheat germ agglutinin coupled to horseradish peroxidase applied to the central end of the sectioned pelvic nerve. The sub-populations of lumbosacral neurons innervating the corpus cavernosum of the penis or the dome of the bladder were identified using transsynaptic retrograde labeling by pseudorabies virus injected into these organs in different rats. In both wheat germ agglutinin-labeled and pseudorabies virus-labeled rats, serial coronal sections were cut through the spinal L5-S1 segments. Labeled neurons were revealed by histochemistry (peroxidase experiments) or immunohistochemistry (pseudorabies virus experiments). By means of a three-dimensional reconstruction software developed in our laboratory, three-dimensional models were calculated from each spinal section image series. They revealed the spatial organization of (i) preganglionic neurons and (ii) neurons innervating the bladder or the penis. The different three-dimensional models were subsequently merged into a single one which revealed the segregation, within the sacral parasympathetic nucleus, of the sub-populations of neurons. Neurons labeled by virus injected into the penis extended predominantly from the rostral part of the L6 segment to the rostral part of the S1 segment while those labeled by bladder injections were distributed predominantly from the caudal part of the L6 segment to the caudal part of the S1 segment. These results support the hypothesis of a viscerotopic organization of sacral neurons providing the spinal control of pelvic organs.

Animals↗
PubMed2000

The safety and efficacy of a single dose (500 mg or 1 g) of intravenous magnesium sulfate in neuropathic pain poorly responsive to strong opioid analgesics in patients with cancer.

Neuropathic pain may respond poorly to morphine and is often difficult to relieve. Recent attention has been drawn to the role of the N-methyl-D-aspartate (NMDA) receptor in the potentiation of neuropathic pain. Magnesium is known to block the NMDA receptor. It reduces the neuropathic pain response in animals, and attenuates postoperative pain and migraine in humans. We have examined the safety, tolerability, and efficacy of two intravenous doses of magnesium sulfate in 12 patients with neuropathic pain due to malignant infiltration of the brachial or lumbosacral plexus. The first six patients received 500 mg, the remainder 1 g. Apart from a mild feeling of warmth at the time of the injection, both doses were well tolerated. After receiving 500 mg, three patients experienced complete pain relief and two experienced partial pain relief for up to 4 hours duration; pain was unchanged in one patient. After receiving 1 g, one patient experienced complete relief and four experienced partial pain relief of similar duration; pain was unchanged in one patient. Intravenous magnesium sulfate in these doses appears to be safe and well tolerated. A useful analgesic effect may be obtained in some patients and further evaluation is warranted.

Aged↗