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PubMed1976

[Gross and light microscopic observations of the pudendal nerve of the guinea pig (author's transl)].

Using thirty six adult guinea pigs, the course and distribution of the pudendal nerve was observed macroscopically and then the constitution of the myelinated nerve fibers in these branches was studied with the fan-wise split preparation method (Fukuyama) and the cross sections embeded in paraffin wax. The main findings are summarized as follows: 1) The pudendal plexus in the guinea pig is formed most frequently by a bigeminal nerve which arises from the ventral ramus of the second sacral nerve at an average rate of 55.0% and the pudendal nerve is so independent from the sciatic nerve that the most part of the bigeminal nerve runs into the pudendal nerve. 2) The perineal nerve of the guinea pig arises most frequently with four roots (43.3%). The myelinated fiber constitution of this nerve is as follows: The small-sized fibers occupy 49.8%, the medium--sized 21.9%, the large--sized 15.1%, the maximum--sized 13.1% on an average, and the nerve fiber diameters observed in the cross section shows a bimodality in their distribution, of which the fibers in the higher peak are 1 mu to 2 mu and in the lower peak 5 mu to 8 mu. 3) The dorsal nerve of the penis or clitoris of the guinea pig arises most frequently with one root from the originating roots of the perineal nerve. The relationship between the sciatic and dorsal nerve appears to be scanty. The myelinated fibers of this nerve comprise 50.8% of small--sized, 28.4% of medium--sized, 14.7% of large--sized and 6.2% of maximum--sized fibers on an average. The fiber sized histograms constructed in the cross section shows a unimodality laying at 1 mu to 3 mu and the dorsal nerve of the clitoris contains more medium fibers 3 mu to 6 mu than the perineal nerve. From these results, it seems clear that the genital corpuscles are supplied by these medium fibers. 4) The inferior rectal nerve of the guinea pig arises from the perineal nerve in all cases, however, it is very slender. 5) The branch to the Obturator internus arises from the originating root or main trunck of the perineal nerve (51.7%). The myelinated fiber constitution of this branch is as follows: The maximum--sized fibers occupy 67.6%, the large--sized 16.2%, the small--sized 9.5% and the medium sized 6.8%. On the other hand, the fiber diameters observed in the transverse section are distributed around three peaks lying at 1 mu, 8 mu to 9 mu and 12 mu to 13 mu. 6) The branch to the accessory head of the Semitendinosus arises from the pudendal nerve at an average rate of 91.7%, of which this branch arises most frequently with one root from the originating root of the perineal nerve. The myelinated fiber constitution is as follows: The maximum--sized fibers 50.0%, the large--sized 23.9%, the small--sized 15.9% and the medium--sized 10.2% on an average. The histogram shows that myelinated fibers in this muscular branch consist of two groups of 1 mu to 2 mu and 12 mu to 14 mu...

Animals↗
PubMed1985

The components of the hypogastric nerve in male and female guinea pigs.

A quantitative study has been made of the neural components of the hypogastric nerves of male and female guinea pigs using retrograde transport of horseradish peroxidase (HRP) to identify the population of neurones projecting in the nerve trunk, and electronmicroscopic analysis of the myelinated and unmyelinated axons present. Application of HRP to the transected axons of the hypogastric nerve labelled the cell bodies of sensory neurones in lumbar and sacral dorsal root ganglia, preganglionic neurones in the lumbar and sacral spinal cord, and postganglionic neurones in the inferior mesenteric ganglion and in the lumbar paravertebral chain; some ganglion cells of the pelvic plexus were also labelled. The number and distribution of each type of neurone with axons in the hypogastric nerve differed between the sexes: in particular, about twice as many preganglionic axons were present in the male as in the female.

Afferent Pathways↗
PubMed1995

Innervation of the smooth muscle of the lower urinary tract.

The lower urinary tract in mammals consists of the bladder, a storage organ for urine, and the urethra through which urine is expelled to the outside. In the male the urethra extends outside the body as the penis. The lower urinary tract is innervated by pelvic (parasympathetic) nerves and hypogastric nerves which combine on each side at the pelvic plexus. Fibres pass to the bladder, urethra, genital organs, rectum and blood vessels. In addition to the pelvic and hypogastric nerves there is sacral outflow to skeletal muscle, such as the external sphincters of the urethra and anus, in the pudendal nerve and the sympathetic chain extends caudally with branches lying in the sacral outflow that supply the penis and other organs though not the bladder. Bladder evacuation and penile erection are produced by activity of the pelvic nerves whereas sympathetic activity usually dominates during urine storage and penile flaccidity, though it may not be essential for either.

Animals↗
PubMed2003

Choroid plexus carcinoma presented with spinal dysfunction caused by a drop metastasis: a case report.

A 2-year-old girl demonstrating gait disturbance and dysuria was evaluated and showed two large remote tumors at the left lateral ventricle and lower spinal canal. Pathological analysis demonstrated both of the tumors to be choroid plexus carcinoma (CPC) with high MIB-1 labeling index. The enhanced mitotic propensity would have contributed to an early stage of drop metastasis from the primary site to the sacral sac and following accelerated formation of a longitudinal tumor, which had grown in the subarachnoid space conforming to the spinal canal and finally caused the presenting symptoms of spinal dysfunction. This report shows that CPC can develop exophytically in the subarachnoid space as well as in the ventricle simultaneously before appearance of clinical symptoms and confirms the importance of extensive neuroimaging in its evaluation.

Brain Neoplasms↗
PubMed1984

Neuroanatomy of penile erection: its relevance to iatrogenic impotence.

The neuroanatomy of erection in men is not well defined. Recently, we isolated successfully the cavernous nerves for acute and chronic neurostimulation to induce penile erection in dogs and monkeys. We then investigated the anatomy of these nerves in humans by cadaveric dissection and serial histologic sectioning. Our experience in tracing the spinal nuclei responsible for vesical and urethral function by transportation of horseradish peroxidase enabled us to explore the location and organization of the spinal center for erection. Thus, systemic knowledge of the neuroanatomy of erection was accumulated. The spinal nuclei for control of erection are located in the intermediolateral gray matter at the S1 to S3 and T12 to L3 levels in dogs, and the S2 to S4 and T10 to L2 levels in humans. From these sacral nuclei axons issue ventrally and join the axons of the nuclei for the bladder and rectum to form the sacral visceral efferent fibers. These fibers emerge from the anterior root of S2 to S4, and join the sympathetic fibers to form the pelvic plexus, which then branches out to innervate the bladder, rectum and penis. The fibers innervating the penis (cavernous nerves) travel along the posterolateral aspect of the seminal vesicle and prostate, and then accompany the membranous urethra through the genitourinary diaphragm. These fibers are located on the lateral aspect of the membranous urethra and ascend gradually to the 1 and 11 o'clock positions in the proximal bulbous urethra. Some of the fibers penetrate the tunica albuginea of the corpus spongiosum, while others spread to the trifurcation of the terminal internal pudendal artery and innervate the dorsal, deep and urethral arteries. Shortly before the 2 corpora cavernosa merge the cavernous nerves penetrate the tunica albuginea along with the deep artery and cavernous vein. The terminal branches of these nerves innervate the helicine arteries and the erectile tissue within the corpora cavernosa. Because of the intimate relationship of the cavernous nerves to the rectum, prostate and urethra, they can be damaged easily during urological and pelvic procedures. This systemic knowledge of the human cavernous nerves from the spinal center to the erectile tissue should permit a better understanding of erection and impotence. Furthermore, with the aid of intraoperative neurostimulation, the cavernous nerves may be identified and preserved, thereby preventing iatrogenic impotence.

Animals↗
PubMed1995

Intraoperative somatosensory evoked potential monitoring during acute pelvic fracture surgery.

Independent clinical neurological evaluation and intraoperative somatosensory evoked potential (SSEP) monitoring was performed on 30 vertically unstable hemipelvis fractures in 28 patients undergoing acute open reduction and internal fixation. Preoperative ipsilateral neurologic injury of the sciatic/lumbosacral plexus was noted in 15 of 30 fractures (50%). Significant unilateral SSEP changes occurred during manipulative reduction of two displaced sacroiliac joints and one sacral fracture. Because of the expeditious response of the surgical team, with release of traction/retraction, SSEP returned to baseline and no patient sustained an iatrogenic nerve injury or worsening of their preoperatie neurologic status. The incidence of postinjury lumbosacral plexopathy in unstable pelvic fractures is high (50%) when careful preoperative evaluation including SSEP is performed. The use of intraoperative SSEP monitoring is feasible in acute posterior pelvic fracture surgery and can help identify potential intraoperative iatrogenic lumbosacral neurological compromise.

Adolescent↗
PubMedDate not supplied

[A rare case of nerve-sheath sarcoma with rhabdomyoblastic differentiation (malignant triton tumor)].

Malignant peripheral nerve sheath tumors (MPNST) are spindle-cell sarcomas that appear in a setting of neurofibroma or schwannoma or are associated with peripheral nerves or demonstrate nerve sheath differentiation. Malignant triton tumor (MTT) is a subtype of MPNST that also contain tissue with skeletal muscle differentiation (embryonal, plemorphic and botryoid rhabdomyosarcoma). The estimated incidence of MPNSTs in patients with NF1 is 2-5% compared with 0.0001% in the general population and approximately 69% of the reported cases of MTT are associated with von Recklinghausen disease. In July 2002 a 37-year old man was readmitted to the Department of Oncologic Surgery of the S. Camillo-Forlanini Hospital in Rome for both a right-sided retroperitoneal paravertebral not palpable mass, incidentally detected at a follow-up MRI, and a left-sided popliteal mass, discovered at clinical evaluation. Seventeen months before, when the patient underwent surgery at the same Department for both a left-sided paravertebral inferior mediastinal neurofibroma and a right-sided axillary neurofibroma, diagnosis of von Recklinghausen disease (NF1) was made, according to the criteria established by the NIH Consensus Development. Conference on Neurofibromatosis of 1987. A xifopubic laparotomy was performed: the tumor appeared to be localized, well-capsulated and strictly associated to the lumbar and sacral nervous radicles (L4, L5, S1) without evidence of invasion. The tumor was completely resected with sparing of the psoas muscle and the lumbar plexus through a subperineural dissection technique. No intra-operative pathologic examination was performed. Postoperative pathologic findings showed evidence for a trition tumor. The popliteal mass was resected too and resulted to be a neurofibroma just like the tumors resected 17 months before when diagnosis of von Recklinghausen disease was made. The patient was disease free 6 months after initial surgery. Sarcoma arising in anatomic site other than extremity and superficial trunk are often more difficult to control because of anatomic constraints, delayed disease presentation, proximity to neurovascular and osseous structures and toxicity for normal adjacent tissues that limits the use of adequate radiation doses. Indeed, the anatomic site is an important prognostic factor in STS and the prognosis for retroperitoneal tumors is considerably worse than for extremity tumors. Reported local recurrence rates for retroperitoneal sarcomas range from 40% to 80% and, in marked contrast to extremity STS, most of patients can and do die from local recurrence in the absence of metastasis. In contrast to the benefit most patients with high grade soft tissue sarcomas of the extremities receive from adjuvant radiation and chemotherapy, these modalities have been of little value for retroperitoneal tumors. To overcome the problem of dose limitation, intraoperative electron beam radiotherapy (IORT) in combination with ERBT has been proposed. IORT plus ERBT was found to improve local control of disease in recent clinical trials. Current chemotherapy for retroperitoneal sarcomas is ineffective. Local adjuvant therapy such as intraperitoneal chemotherapy or experimental immunotherapy seems to be attractive in theory, but needs further investigations through prospective randomized multicentric trials. In conclusion, to date aggressive surgical management remains the most effective modality for selected primary and recurrent retroperitoneal soft tissue sarcomas including MPNSTs and the subtype MTT. Patients with incomplete resection and other risk factors such as younger age and high grade tumors may be suitable candidates for investigational adjuvant therapy.

Adult↗
PubMed2000

[Preserving autonomic nerves in rectal surgery. Results of surgical preparation on human cadavers with fixed pelvic sections].

INTRODUCTION: Preservation of sexual function and voiding capacity after rectal cancer surgery has increased after adopting the technique of nerve-sparing dissection and total mesorectal excision. Still the rate of sexual and urinary dysfunction ranges between 25 and 67%. The precise locations where nerve damage occurs have not been looked at systematically. MATERIAL AND METHODS: In ten human corpses and two formalin-fixed human pelvises the autonomous pelvic nerves were isolated. Their relation according to surgical mobilization of the rectum were photodocumented. RESULTS: Pelvic autonomous nerves are clearly defined structures with only minor interindividual variability. The inferior mesenteric plexus forms a dense network around the inferior mesenteric artery (AMI) to a distance of 5 cm from the aorta. The distance between the lateral rectum and the pelvic plexus is only 2-3 mm. The anterior rectum is almost directly adherent to the neurovascular bundle, separated only by Denonvillier's fascia. The parasympathetic branches of the sacral segments S2-S5 cannot be isolated using the standard surgical approach. CONCLUSION: (1) The nomenclature of fascias and the course of the autonomous pelvic nerves is not clearly defined in the literature; (2) a high tie of the AMI leads to damage of the sympathetic nerves; (3) the narrow space between the anterior and lateral rectum makes sharp dissection under direct vision necessary; (4) fascias and nerves can be used as guiding structures during mobilization; (5) a preservation of selected parasympathetic roots in the small pelvis is not feasible using the standard surgical approach.

Autonomic Nervous System↗
PubMed2003

Presacral arteriovenous fistula: case report.

OBJECTIVE AND IMPORTANCE: We describe a case of arteriovenous fistula in front of the sacrum. Drainage induced epidural venous dilation in the sacral spinal canal. The fistula was embolized endoarterially with n-butyl-2-cyanoacrylate via its iliac arterial feeders. In follow-up digital subtraction angiography 1 month later, the fistula was found to be totally closed. The patient was followed up clinically for 2.5 years. She has remained symptom-free. CLINICAL PRESENTATION: A previously healthy 43-year-old woman presented with severe gluteal and perineal pain and a local sensation of hyperesthesia. The primary computed tomographic scan of the lumbosacral spine was normal, and emergency laparoscopy showed no signs of any pathological lesions. Magnetic resonance imaging discovered an unidentified mass in the sacral spinal canal, and the patient was hospitalized for neurosurgery. However, surgery on this mass had to be discontinued because of profuse bleeding, and the patient was referred for angiography. INTERVENTION: Diagnostic catheter angiography revealed a high-flow arteriovenous fistula anterior to the sacrum, and the mass detected earlier by magnetic resonance imaging seemed to be a dilated epidural vein draining the fistula. The feeders of the fistula originated in both internal iliac arteries, and the fistula was occluded via these arteries in two angiographic sessions. CONCLUSION: A paraspinal arteriovenous fistula may have venous drainage through the epidural venous plexus, and the ectatic veins may induce radicular symptomology. To the best of our knowledge, a paraspinal fistula at such a presacral location has not been documented previously. An unidentified mass in the sacral spinal canal should be suspected of being a dilated vascular structure. Prompt angiographic examinations with an option for embolization should be performed, and open surgical intervention should be avoided.

Adult↗
PubMed2004

The gluteal perforator-based flap in repair of pressure sores.

The gluteal perforator-based flap is designed according to the localisation of sacral perforator vessels. These vessels penetrate the gluteus maximus muscle and reach the intrafascial and suprafascial planes, and the overlying skin forming a rich vascular plexus. The gluteal perforator-based flaps described in this paper are highly-vascularised, have minimal donor site morbidity, do not require the sacrifice of the gluteus maximus muscle and rarely lead to post-operative complications. We believe these easy-to-perform flaps might be considered as the first choice in the repair of gluteal pressure sores.

Adult↗
PubMed1976

[Vascularization of the anal canal].

The arterial blood supply of the anal canal derives from the superior, middle and inferior rectal arteries, whose branches reach the anal submucosa. Three main arterial trunks in the right anterior, right posterior and left lateral positions can be isolated below the pectinate line. They come, for the most important part, from the superior rectal artery. On the course of the anal submucosal venous plexus are fusiform, saccular or serpiginous dilatations confined to the lower half of the anal canal. This plexus is mainly tributary of the superior rectal vein to the portal system and secondly, of the middle and inferior rectal veins and the lateral sacral veins to the inferior vena cava. Arterio-venous direct communications have been demonstrated by serial section and by radiography of cadaveric specimens and by selective inferior mesenteric arteriography in patients. The erectile property of the anal submucosa as suggested by large vascular spaces, arterio-venous shunts and glomic systems may function in the erectile mechanism.

Anal Canal↗
PubMedDate not supplied

Sacral agenesis with associated anomalies (caudal regression syndrome): autopsy case report.

Autopsy findings of an infant with sacral agenesis and multiple anomalies of the lower half of the body which fit the description of the caudal regression syndrome are reported. The lumbosacral plexus of nerves was more abundant on one side despite symmetrical lumbar vertebral dysgenesis with agenesis below S1. The presence of intrathecal kidney tissue has not been previously reported in this syndrome. Diethylopropion hydrochloride, an appetite supressant, which was ingested by the patient's mother during the first month of pregnancy, was cited as a possible etiologic agent.

Abnormalities, Multiple↗