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PubMed1991

Threshold dose for peripheral neuropathy following intraoperative radiotherapy (IORT) in a large animal model.

Radiation injury to peripheral nerve is a dose-limiting toxicity in the clinical application of intraoperative radiotherapy, particularly for pelvic and retroperitoneal tumors. Intraoperative radiotherapy-related peripheral neuropathy in humans receiving doses of 20-25 Gy is manifested as a mixed motor-sensory deficit beginning 6-9 months following treatment. In a previous experimental study of intraoperative radiotherapy-related neuropathy of the lumbro-sacral plexus, an approximate inverse linear relationship was reported between the intraoperative dose (20-75 Gy range) and the time to onset of hind limb paresis (1-12 mos following intraoperative radiotherapy). The principal histological lesion in irradiated nerve was loss of large nerve fibers and perineural fibrosis without significant vascular injury. Similar histological changes in irradiated nerves were found in humans. To assess peripheral nerve injury to lower doses of intraoperative radiotherapy in this same large animal model, groups of four adult American Foxhounds (wt 20-25 kg) received doses of 10, 15, or 20 Gy to the right lumbro-sacral plexus and sciatic nerve using 9 MeV electrons. The left lumbro-sacral plexus and sciatic nerve were excluded from the intraoperative field to allow each animal to serve as its own control. Following treatment, a complete neurological exam, electromyogram, and nerve conduction studies were performed monthly for 1 year. Monthly neurological exams were performed in years 2 and 3 whereas electromyogram and nerve conduction studies were performed every 3 months during this follow-up period. With follow-up of greater than or equal to 42 months, no dog receiving 10 or 15 Gy IORT shows any clinical or laboratory evidence of peripheral nerve injury. However, all four dogs receiving 20 Gy developed right hind limb paresis at 8, 9, 9, and 12 mos following intraoperative radiotherapy. These experimental data suggest that intraoperative doses of less than 20 Gy may not result in clinically significant peripheral nerve injury with follow-up of 3.5 years. Longer (5 yrs) follow-up with planned sacrifice of the remaining dogs is scheduled to assess any late peripheral nerve damage.

Animals↗
PubMed2004

Pattern of sensory innervation of the perineal skin in the female rat.

Here we describe the nerves innervating the perineal skin together with their sensory fields in the adult female rat. Electrophysiological recording showed that the lumbosacral and L6-S1 trunks, in part by way of the sacral plexus, transmit sensory information from the perineal skin via four nerves: the viscerocutaneous branch of the pelvic nerve innervating the skin at the midline between the vaginal opening and anus, the sensory branch of the pudendal nerve innervating the clitoral sheath, the distal perineal branch of the pudendal nerve innervating a broad area of skin adjacent to the vaginal opening and anus, and the proximal perineal branch of the sacral plexus innervating a broad area of skin adjacent to the clitoris and vaginal opening. The sensory fields of three of these nerves overlapped to some degree: the viscerocutaneous branch of the pelvic and the distal perineal branch of the pudendal nerves at the midline skin between the vaginal opening and the anus, and the distal perineal branch of the pudendal nerve and the proximal perineal branch of the sacral plexus at the skin lateral to the vaginal opening. Such overlap might provide a safeguard helping to ensure that somatosensory input from the perineal region important for triggering reproductive and nonreproductive reflexes reaches the CNS.

Animals↗
PubMed1992

Schwann cells are not required for guidance of motor nerves in the hindlimb in Splotch mutant mouse embryos.

The topogenesis of the hindlimb nerves of Splotch homozygous mutant mouse embryos was studied using light and electron microscopy. Homozygous mutants show multiple defects of neural crest-derived tissues. The defects increase along a rostro-caudal gradient. The cervical and upper thoracic segments have small spinal ganglia, and Schwann cells are associated with the spinal nerves. In the lumbo-sacral region neurulation is not complete, and the derivatives of the neural crest are missing. The lumbo-sacral nerve trunks are formed by ventral roots only. They are occasionally associated with presumptive glial cells that have migrated from the spinal cord for a short distance. Beyond the vertebral primordia, the spinal nerves are not accompanied by Schwann cells. No compartmentalization of the axons within the lumbo-sacral nerves was visible, whereas Schwann cells did segment the nerve into the fascicles in brachial nerves. The lumbo-sacral plexus develops, and its branches grow into the hindlimb despite the absence of Schwann cells. On day 13.5 of gestation, the lumbo-sacral nerve trunks extend well into the distal calf. They are topographically correctly positioned. Their branches enter the muscle primordia and form contacts with their mesenchymal cells though the cutaneous branches are missing. Generally, the outgrowth of lumbo-sacral nerves is slower than in phenotypically normal littermates, whose nerves reach the foot plate at corresponding stages of development. These results demonstrate that the lumbo-sacral plexus and the topographically correct position of lumbo-sacral nerve trunks develop despite the absence of Schwann cells. Therefore Schwann cells are not necessary for the outgrowth and guidance of axons within the limb.

Animals↗
PubMed1990

Computer-aided intelligence: application of an expert system to brachial plexus injuries.

When confronted with a patient with a brachial plexus injury, how often as neurosurgeons do we consult an atlas to confirm the anatomy of the brachial plexus and then attempt to establish the location of the lesion? Similar difficulties are encountered with lumbar and sacral plexus lesions. In a project organized to assist the neurosurgeon in this time-consuming task, a computer program that can rapidly determine the site of a lesion in a brachial, lumbar, or sacral plexus injury was created. Using known anatomical pathways (37 clinically relevant upper and 20 lower extremity muscle innervations), and relying solely upon the neurological motor examination, rapid computer-assisted diagnosis is possible. When more than one final common pathway lesion occurs (for example, multiple root avulsions of the brachial plexus), possible lesion sites can be obtained. An interactive dialogue between the user and the program helps to determine the location of the lesion. The program can be run on any IBM-compatible personal computer and is presented as an instrument that provides assistance in cases of complex peripheral nerve injuries, when expert consultants are unavailable. In addition, it can be used as an aid to learning and as a review of basic neuroanatomy.

Artificial Intelligence↗
PubMedDate not supplied

Continuous parasacral sciatic nerve block: two case reports.

OBJECTIVE: This study investigated the use of a continuous parasacral sciatic nerve block for anesthesia and postoperative analgesia for lower extremity surgery. METHODS: A continuous parasacral sciatic nerve block was performed in two patients (triple ankle arthrodesis and below-knee amputation). The sacral plexus was identified using an insulated Tuohy needle and a nerve stimulator. A catheter was placed near the elements of the sacral plexus via the Tuohy needle. RESULTS: In both patients, surgical anesthesia was successfully established through the parasacral catheter with lidocaine 1% (1/200,000 epinephrine), and postoperative analgesia was successfully established with a bolus of bupivacaine 0.375% (1/200,000 epinephrine) and maintained with a continuous infusion of bupivacaine 0.1% (8 mL/h) for 48 hours. CONCLUSION: We conclude that continuous parasacral sciatic nerve block can provide anesthesia and long-term analgesia for operative procedures of the foot and leg.

Amputation, Surgical↗
PubMed1988

Clinical significance of sacral and pudendal nerve anatomy.

The neuroanatomy and neurophysiology of the external urethral closure mechanisms still are under debate because the motor fibers that emanate from the sacral plexus and pudendal nerve to supply this segment have not been traced, nor has their functional interrelationship been established. Therefore, we dissected 3 male human cadavers (aged 31 to 69 years) by tracing the entire sacral plexus, particularly the pudendal nerve, from the cauda equina throughout the branching of the nerves to their final destination. The dissection demonstrated that the extrinsic urethral sphincter, formed by the rhabdosphincter around the membranous urethra as well as the levator ani muscle and pelvic floor (especially the transversus perinei muscle), is innervated by somatic nerve fibers that emanate primarily from sacral roots S2 and S3. In 5 patients with neurogenic lower urinary tract dysfunction electrostimulation of the sacral root and pudendal nerve markedly increased intraurethral closure pressures. Stimulation of the pudendal nerve or its transversus perinei branch alone resulted in an increase in intraurethral closure pressure to 60 to 70 cm. water--an increase similar to that produced by stimulation of the sacral root without neurotomy. By means of neurotomy and/or neural blockade with lidocaine we were able to differentiate between the contributions of each muscular element to the external sphincteric mechanism. Almost 70 per cent of the closure pressure of the external urethral sphincter is induced by stimulation of the S3 ventral root, while the other 30 per cent derives from S2 and S4 neuronal impulses.

Adult↗
PubMed1982

Malignant neurilemmoma of left atrium.

A 31-year-old woman, whose chief complaint was back pain, was found to have an echocardiographic abnormality suggestive of a left atrial myxoma. Angiography clearly showed a large radiolucent mass protruding from the left atrium into the left ventricle during diastole. X-rays of the sacrum disclosed the presence of a malignant tumour. Biopsy specimens taken from the tumour in the sacral plexus showed a malignant neurilemmoma. Despite extensive chemotherapy, widespread metastases developed and the patient died four months after admission. Necropsy disclosed three discrete tumours in the left atrium, which were found to be malignant neurilemmoma, shown on histology to be metastases from the primary in the sacral plexus.

Adult↗
PubMed1988

Retroperitoneal nerve sheath tumors: an unusual cause of pelvic mass.

Solitary nerve sheath tumors can arise in peripheral, cranial, or sympathetic nerves at virtually any anatomic site. Although origin along the nerves of the retroperitoneal space is not uncommon, these tumors rarely present as pelvic masses. We describe two patients found to have benign nerve sheath tumors of the sacral plexus. Neurilemomas (schwannomas) and neurofibromas are thought to result from a proliferation of perineural cells. These tumors are characteristically firm, smooth, and asymptomatic. They range in size from 1-2 mm to over 20 cm. Surgical excision can usually be accomplished by enucleation of the tumor without damage to the adjacent nerve. Resection of sacral plexus tumors requires knowledge of pelvic retroperitoneal anatomy to avoid injuries to the nearby vascular and urinary structures.

Adult↗
PubMedDate not supplied

The parasacral sciatic nerve block.

BACKGROUND AND OBJECTIVES: The clinical utility of a new parasacral approach for conduction block of the sciatic nerve was investigated, with critical examination of onset, extent, and success rates when this block was used for surgical procedures below the knee. METHODS: Thirty ASA I-III patients presenting for surgery on the lower limb were enrolled. All received 30 mL of 1.5% lidocaine with 1:200,000 epinephrine following nerve stimulator identification of the sciatic nerve at < or =0.2 mA or less. Trans-sartorial saphenous nerve blocks were performed to provide anesthesia to the medial leg. RESULTS: Overall success for surgical anesthesia with this block was 97%. All components of the sacral plexus could be blocked with this approach, and 93% of patients displayed evidence of obturator nerve motor block. However, no patient displayed evidence of obturator sensory anesthesia that could be mapped. Saphenous nerve blocks were 100% effective in providing surgical anesthesia for the procedures performed. CONCLUSIONS: The parasacral approach to the sciatic nerve exhibits a high success rate, resulting in anesthesia of the entire sacral plexus and generally in motor block of the obturator nerve was an interesting observation.

Adult↗
PubMed1977

[Reverberation of the hindlimb rudimentation on its innervation in squamate reptiles].

When the dimensional reduction of the hind limb begins, a first caudal displacement of the lombar part of the lombo-sacral plexus - which involves the loss of the first root of the sacral part -- appears with a threshold in the increase in the number of presacral vertebrae. This a first indication of the serpentiform tendancy. Others thresholds can conduct to produce the disappearance of the sacral vertebrae and sacral root. The qualitative reduction only concerns the terminal branches of the plexus and does not seem to be associated with the vertebral elongation. If a caudo-proximal reduction of the brachial plexus occurs early in the lepidosaurian line and exists in all the Squamata, even in the Iguana which have well developed limbs, it is not the same for the reduction of the lombo-sacral plexus which does not appear in these Iguana. At last, if the reduction modalities of the both plexus are often differents, their supposed displacements facilitate the extension of the intermediate vertebral region.

Animals↗
PubMed1991

Unusual amyloid polyneuropathy with predominant lumbosacral nerve roots and plexus involvement.

We report a 25-year-old patient with a progressive asymmetric peripheral neuropathy of the distal lower limbs. Imaging studies showed enlargement of lumbosacral roots, plexus, and proximal sciatic nerve. Sacral plexus biopsy revealed amyloidosis associated with endoneurial edema. Immunohistochemistry with anti-prealbumin, serum amyloid A, and immunoglobulin light chain antisera failed to label the amyloid.

Adult↗
PubMedDate not supplied

[Plexus lesions following radiation therapy. Report of nineteen cases (author's transl)].

Nineteen patients with plexus lesions following radiation therapy were investigated: fifteen with brachial plexus, 4 with lumbar or sacral plexus involvement. Symptoms at onset are usually sensory. Motor disturbances occur either simultaneously or after some delay, their course is generally gradual and unfavourable. Areflexia appears early and was present in every case. Important cutaneous lesions (radiodermitis) and considerable induration of soft tissues were observed in every patient. Diagnosis is a relapse of the mitotic process. Severity of prognosis makes imperative a definite technique of radiation therapy. In all the patients included in this study, dosage had exceded 1,600 rets. Patients were tentatively treated with D-penicillamine, an inhibitor of collagen synthesis.

Brachial Plexus↗
PubMed1982

[Reconstruction of the lumbosacral plexus of an embryo at stage 23 (25mm) and an embryo at stage 16 (7,5mm)].

Two embryos, one at stage 23 and another at stage 16, are reconstructed in view of studying the evolution of the lumbosacral plexus. At stage 16, the sacral plexus begins its development with anastomosis of L5, S1 and S2 roots, while the pelvic member is scarcely sketched. At stage 23, the evolution is complete, the pelvis is entirely constitued and the femoral, sciatic and obturator nerves of adult type. The coccygian plexus is in process of construction.

Humans↗
PubMed1980

Ischaemic neuropathy of the lumbosacral plexus following intragluteal injection.

A lesion of the lumbo sacral plexus may result from an inadvertent intra-arterial injection of vasotoxic drugs into one of the gluteal arteries. Symptoms and follow-up of three cases are reported. The neuropathy is attributed to a toxic endarteritis with retrograde propagation of spasm and thrombosis. Swelling an bluish discoloration of the buttocks ("embolia cutis medicamentosa") as well as an impaired circulation in the homolateral leg are associated with the neurological syndrome in fully developed cases and makes possible a correct diagnosis.

Adult↗
PubMed2000

The relationship between the lumbosacral enlargement and the conus medullaris during the period of fetal development and adulthood.

The spinal cord is situated within the vertebral canal by the third month of intrauterine life. The spinal cord possesses two symmetrical enlargements, which constitute the segments of the plexuses: the cervical enlargement for the brachial plexus and the lumbosacral enlargement for the lumbar and sacral plexus. In our study, we aimed to investigate the relationship between the termination level of the lumbosacral enlargement (TLLE) and that of the conus medullaris (TLCM) during the period of fetal development and adulthood. We used a total of 75 cases: 25 fetuses (male: 16, female: 9) whose crown-rump length ranged between 90-190 mm, 25 premature and full-term neonates (male: 17, female: 8) whose post-menstrual ages ranged between 33-55 weeks, and 25 adults (male: 12, female: 13) aged between 22-72 years. The dissection technique for fetuses, ultrasonography for premature and full-term newborns, and magnetic resonance imaging (MRI) for adults were used to determine lumbosacral enlargement and TLCM. The differences between the TLCM and the termination level of the largest part of the transverse diameter of the lumbosacral enlargement were investigated. The differences between the TLLE and TLCM were found in different ratios from the period of fetal development to adulthood. Therefore, during medical treatment and surgical procedures this should be taken into account to avoid complications.

Adult↗
PubMed1987

Anatomy and computed tomography of the normal lumbosacral plexus.

The main nerves of the pelvis and lower limbs arise from the lumbar and sacral plexuses. These nerves can be affected by any of a large number of pathologic processes that occur in the paravertebral and pelvic regions. Understanding of the neurological findings related to paravertebral and pelvic pathology needs complete and accurate knowledge of the anatomy of these regions. The axial transverse sections of computed tomography give perfect visualisation of the anatomy of osseous, muscular, and vascular structures of the vertebral and paravertebral area and pelvic walls. Visualisation of the nerves in this regions is much more difficult, because direct demonstration of nervous structures by computed tomography is usually impossible. To be able to identify components of the lumbosacral plexus on axial CT sections the radiologist has to know the location of the nervous structures and the relationships of these structures to vascular, muscular and osseous structures which are easily demonstrated.

Humans↗
PubMed2005

Anatomy and imaging of lumbar plexus.

Sensory and motor innervation of the whole lower limb is due to lumbo-sacral-plexus that arises from the spinal roots L1-S3. The whole lower limb can be blocked from its origin to the foot for surgical procedures or for postoperative analgesia. Single or continuous lumbar plexus blockade can be an alternative to general anesthesia and central block in elective and traumatic hip or femur repair, for knee surgery and for postoperative analgesia. To understand the relative plexus depth and the relationship between the plexus and the closer structure in order to avoid complicance, the aid of imaging technique such as CT-scan, MRI and ultrasounds can be considered.

Anesthesia, Spinal↗