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Background: The superior gluteal artery (SGA) passes in between branches of the lumbosacral plexus after arising from the internal iliac artery. Variations in the course of SGA from the internal iliac artery till it passes out of the pelvis through the greater sciatic foramen are very important during pelvic surgeries. Pseudoaneurysm of SGA caused by iatrogenic injuries can compress branches of the lumbosacral plexus, causing foot drops and sciatica. Aims and Objectives: The aim is to study the course of the SGA in relation to branches of the lumbosacral plexus. Materials and Methods: A cross-sectional observational study was done on 25 formalin-fixed human adult cadavers. Dissections were performed in the pelvic region and branches of the internal iliac artery and lumbosacral plexus were identified. SGA was traced on both sides from origin till passing out of the greater sciatic foramen and its relation to branches of lumbosacral plexus was recorded. Results: Three types of pathways taken by SGA were identified in relation to the lumbosacral plexus. The most common path taken by the SGA was between the lumbosacral trunk (LST) and the first sacral nerve. Thirty-five out of 50 were of this type (70%). Ten out of 50 had the second most common type which was between L4 and L5 branches of LST (20%). Five cadavers had SGA lateral to LST (10%). Ten cadavers out of 25 (40%) had side differences in the type of course taken by SGA in relation to the lumbosacral plexus. Conclusion: A surgeon must keep in mind variations in the path taken by SGA in relation to the lumbosacral plexus to prevent pseudoaneurysms of SGA, which in turn can compress branches of lumbosacral plexus, causing foot drop and sciatica.

Background: The superior gluteal artery (SGA) passes in between branches of the lumbosacral plexus after arising from the internal iliac artery. Variations in the course of SGA from the internal iliac artery till it passes out of the pelvis through the greater sciatic foramen are very important during pelvic surgeries. Pseudoaneurysm of SGA caused by iatrogenic injuries can compress branches of the lumbosacral plexus, causing foot drops and sciatica. Aims and Objectives: The aim is to study the course of the SGA in relation to branches of the lumbosacral plexus. Materials and Methods: A cross-sectional observational study was done on 25 formalin-fixed human adult cadavers. Dissections were performed in the pelvic region and branches of the internal iliac artery and lumbosacral plexus were identified. SGA was traced on both sides from origin till passing out of the greater sciatic foramen and its relation to branches of lumbosacral plexus was recorded. Results: Three types of pathways taken by SGA were identified in relation to the lumbosacral plexus. The most common path taken by the SGA was between the lumbosacral trunk (LST) and the first sacral nerve. Thirty-five out of 50 were of this type (70%). Ten out of 50 had the second most common type which was between L4 and L5 branches of LST (20%). Five cadavers had SGA lateral to LST (10%). Ten cadavers out of 25 (40%) had side differences in the type of course taken by SGA in relation to the lumbosacral plexus. Conclusion: A surgeon must keep in mind variations in the path taken by SGA in relation to the lumbosacral plexus to prevent pseudoaneurysms of SGA, which in turn can compress branches of lumbosacral plexus, causing foot drop and sciatica. [ABSTRACT FROM AUTHOR]

Study Design A descriptive cross-sectional study of the anatomical variations, morphometry, and histology of the iliolumbar veins (ILVs). Purpose This study aimed to describe the anatomical variations of the ILVs and determine their tissue composition in South African cadavers of European descent. Overview of Literature A safe anterior surgical approach to the L4/L5 intervertebral disc space requires understanding the anatomy of the ILVs. Limited understanding of ILVs and their variations may lead to inadvertent avulsion of veins with subsequent hemorrhage and damage to the adjacent nerves intraoperatively. Variations in ILVs are population specific, but such reports are limited in the South African population. Methods Eighty-nine adult cadavers were dissected to reveal ILV patterns. The variations (origin, course, and drainage pattern), morphometries, and topography of the ILVs were studied. A total of 19 (10 proximal, nine distal) ILVs were processed for hematoxylin and eosin, Masson’s trichrome, and Verhoeff’s histological staining to determine the tissue composition. Results The ILVs were identified in 100% of the cases, and 45% of the ILVs were anastomosed to each other bilaterally. The right-side ILVs terminated into the posterior surfaces of the iliac vessels (p=0.001), whereas the left-side ILVs terminated into the lateral surfaces (p=0.001). The left-side proximal ILVs had higher elastic fiber composition (p=0.030). The ratio of the ILVs’ elastic fibers to collagen fibers was 1:9, and 61% of the cadavers exhibited type 1 ILV pattern. Moreover, 42% of the ILVs were at the S1 vertebral level with 31% lying between L4 and L5 spinal nerve roots. The obturator nerve coursed anteriorly to the ILVs in 96% of cases. Conclusions The ILV variations described for South Africans present new additional patterns, such as bilateral anastomosis and laterality of the terminal drainage. The ILVs have more collagen fibers than elastic fibers, predisposing them to avulsion during surgical retraction. The identification of all the ILVs is crucial to minimize inadvertent hemorrhage and damage to adjacent structures.

Study Design: A descriptive cross-sectional study of the anatomical variations, morphometry, and histology of the iliolumbar veins (ILVs). Purpose: This study aimed to describe the anatomical variations of the ILVs and determine their tissue composition in South African cadavers of European descent. Overview of Literature: A safe anterior surgical approach to the L4/L5 intervertebral disc space requires understanding the anatomy of the ILVs. Limited understanding of ILVs and their variations may lead to inadvertent avulsion of veins with subsequent hemorrhage and damage to the adjacent nerves intraoperatively. Variations in ILVs are population specific, but such reports are limited in the South African population. Methods: Eighty-nine adult cadavers were dissected to reveal ILV patterns. The variations (origin, course, and drainage pattern), morphometries, and topography of the ILVs were studied. A total of 19 (10 proximal, nine distal) ILVs were processed for hematoxylin and eosin, Masson's trichrome, and Verhoeff's histological staining to determine the tissue composition. Results: The ILVs were identified in 100% of the cases, and 45% of the ILVs were anastomosed to each other bilaterally. The rightside ILVs terminated into the posterior surfaces of the iliac vessels ( p=0.001), whereas the left-side ILVs terminated into the lateral surfaces ( p=0.001). The left-side proximal ILVs had higher elastic fiber composition ( p=0.030). The ratio of the ILVs' elastic fibers to collagen fibers was 1:9, and 61% of the cadavers exhibited type 1 ILV pattern. Moreover, 42% of the ILVs were at the S1 vertebral level with 31% lying between L4 and L5 spinal nerve roots. The obturator nerve coursed anteriorly to the ILVs in 96% of cases. Conclusions: The ILV variations described for South Africans present new additional patterns, such as bilateral anastomosis and laterality of the terminal drainage. The ILVs have more collagen fibers than elastic fibers, predisposing them to avulsion during surgical retraction. The identification of all the ILVs is crucial to minimize inadvertent hemorrhage and damage to adjacent structures. [ABSTRACT FROM AUTHOR]

To describe an ultrasound-guided lateral pre-iliac (LPI) and parasacral (PS) approach in feline cadavers (phase I) and compare the perioperative analgesic use and complications in cats administered LPI and PS blocks (group PNB) or epidural anesthesia (group EPI) for pelvic limb surgery (phase II). Experimental uncontrolled, anatomic and retrospective cohort study. A group of eight feline cadavers and 52 medical records. Bilateral LPI and PS approaches with 0.1 mL kg–1 of dye to stain the femoral and obturator nerves and the lumbosacral trunk, respectively, were performed on each cadaver. Nerve staining effect was evaluated upon dissections (phase I). Perioperative analgesics use, and complication rates were retrospectively compared between groups PNB and EPI (phase II). Continuous data were compared using the Mann–Whitney U test and the prevalence of events with Fisher's exact test. Differences were considered significant when p < 0.05. Dissections revealed that the LPI approach stained 94% and 75% of the femoral and obturator nerves, respectively. The PS approach stained 100% of the lumbosacral trunks. Cats enrolled in group PNB (n = 23) were administered lower doses of intraoperative opioids than those in group EPI (n = 25) (p = 0.006). Intraoperative rescue analgesia was required in 60% and 17.4% of cats enrolled in groups EPI and PNB, respectively (p = 0.003). Group PNB required more intraoperative anticholinergics than group EPI (p = 0.02). There were no differences in postoperative pain scores, analgesic use and complication rates. The ultrasound-guided LPI and PS approach stained the femoral/obturator nerves and the lumbosacral trunk, respectively, in feline cadavers. Furthermore, PNB was associated with lower intraoperative opioid use and similar postoperative pain and analgesic use compared with epidural anesthesia in a cohort of cats undergoing surgery of the pelvic limb. [ABSTRACT FROM AUTHOR]

Background: We aimed to study the mechanism of sacral nerve injury caused by sacral fractures and the relationship between nerve decompression and nerve function.Methods: First, we observed the anatomical features of lumbosacral nerve root region in Sprague-Dawley rats. Next, the rats were divided into the sham, 10 g, 30 g, and 60 g groups for electrophysiological studies on nerve root constriction injury. Then we studied the biomechanical properties of rat nerve roots, lumbosacral trunk, and sacrum. Finally, we established a finite element analysis model of sacral nerve roots injury in rats and determined the correlation between sacral deformation and the degree of sacral nerve roots injury.Result: Anatomical study showed L5 constitutes sciatic nerve, the length of the L5 nerve root is 3.67 ± 0.15 mm, which is suitable for electrophysiological research on nerve root compression injury. After a series of electrophysiological study of L5 nerve roots, our results showed that nerve root function was almost unaffected at a low degree of compression (10 g). Nerve root function loss began at 30 g compression, and was severe at 60 g compression. The degree of neurological loss was therefore positively correlated with the degree of compression. Combining biomechanical testing of the lumbosacral nerve roots, finite element analysis and neuroelectrophysiological research, we concluded when the sacral foramina deformation is >22.94%, the sacral nerves lose function. When the compression exceeds 33.16%, early recovery of nerve function is difficult even after decompression.Conclusion: In this study, we found that the neurological loss was positively correlated with the degree of compression. After early decompression, nerve root function recovery is possible after moderate compression; however, in severe compression group, the nerve function would not recover. Furthermore, FEA was used to simulate nerve compression during sacral fracture, as well as calculate force loading on nerve with different deformation rates. The relationship between sacral fractures and neurological loss can be analyzed in combination with neurophysiological test results.

Internal iliac artery (IIA) shows great deal of variations in its branching pattern. The knowledge of its variant branches is required for successful surgical, orthopedic, plastic surgery and radiological procedures. We observed variations of some of the branches of right IIA in an adult male cadaver. The iliolumbar artery originated from the main trunk of the IIA. After this, IIA divided into anterior and posterior divisions. The posterior division gave lateral sacral and superior gluteal arteries. Superior gluteal artery pierced the lumbosacral trunk before leaving the pelvis. The anterior division further divided into anterior and posterior trunks. Anterior trunk gave rise to superior vesical, inferior vesical, middle rectal and obturator arteries. The posterior trunk gave two inferior gluteal arteries and an internal pudendal artery.

Schwannomais, usually, benign tumor of nerve sheath that occurs evenly along the spinal cord. Intra-pelvic schwannoma is very rare entity that may arise from lumbosacral nerve roots or from sciatic nerve. Radicular pain of the lower limb as a presenting symptom of pelvic schwannoma is extremely rare. In the current report, the patient is presented with a right sided L5 radicular pain typical of lumbar discopathy. Interestingly, a herniated lumbar disc was noted on lumbosacral magnetic resonance imaging (MRI). In pre-operative studies a large pelvic mass was detected in the right pre-sacral area with solid and cystic components consistent with schwannoma. The patient underwent a low midline laparotomy to evacuate the retroperitoneal mass. Uniquely, we found the tumor to be arisen from lumbosacral trunk not from a root or peripheral nerve. Most cases with intra-pelvic schwannoma present so late with vague abdominal and pelvic discomfort or pain, low back pain, urinary and bowel symptoms because of compressive effect of the tumor, or incidentally following gynecologic work-ups; So, these patients are mostly referred to gynecologists and urologists. A neurosurgeon should have a high degree of suspicion to diagnose such an entity among his or her patients presented with pains typical for discopathy. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives: To reveal the variations of the iliolumbar artery and the iliolumabar veins and their correlation with the surrounding important structures. Methods: We dissected the iliolumbar region bilaterally in 20 formalin-fixed adult cadavers. The diameter of the iliolumbar artery at its origin, its length up to the branching point, the distance between the iliolumbar artery and the inferior margin of the fifth lumbar vertebra and the distance between the iliolumbar artery and the bifurcation point of the common iliac artery, were measured. The pattern of drainage, the dimensions, the points of confluence with the common iliac vein and the obliquity of the iliolumbar vein were noted. The correlation between the iliolumbar artery and the veins to the obturator nerve and the lumbosacral trunk was recorded. Results: The iliolumbar artery originated from the posterior trunk of the internal iliac artery or from the internal iliac artery. The mean diameter of the iliolumbar artery, at its origin, was 3.5±0.5 mm. The mean distance between the origin of the iliolumbar artery and the bifurcation point to the iliac and the lumbar branches was 12.2±5.5 mm. The distance between the origin of the iliolumbar artery and the lower edge of the fifth lumbar vertebra was 43.2±11.6 mm. The distance between the origin of the iliolumbar artery and the bifurcation point of the common iliac artery was 38.7±10.6 mm. The mean distance of the iliolumbar veins from the inferior vena cava, overall, was 35± 9.9 mm. The mean width of the mouth of the iliolumbar vein was10.7 ± 5.1 mm and the mean angle of obliquity of the vein with respect to the long axis of the common iliac vein was 75.50 . The tributaries which drained into the main iliolumbar vein were variable. The iliolumbar artery passed anterior in 70% and it passed posterior to the obturator nerve in 30%. The veins were lying anterior to the obturator nerve in 45% and they were lying posterior in 55%. The multiple tributaries which drained into the iliolumbar vein relation of the tributaries were variable, few passed anterior and few passed posterior. The iliolumbar artery was seen anterior to the lumbosacral trunk in 30%, it was posterior in 54%, it was cleaved in 8% and the branches of the artery were passing on either side of the lumbosacral trunk to enclose it like a clasp in 8%. The veins were anterior to the lumbosacral trunk in 40% and they were posterior in 60%. Conclusion: The anatomical features of the iliolumbar artery, the iliolumbar veins and their correlation with the anatomical landmarks, which were presented here, would be helpful in decreasing the iatrogenic trauma to the neurovascular structures in the iliolumbar region.

The sciatic nerve is the sacral plexus terminal branch. The sacral plexus is formed from the anastomosis of the lumbosacral trunk (L4, L5) with the first three anterior branches of the spinal sacral nerves. The sacral plexus is shaped as a triangle, and it is situated in the subperitoneal space of the pelvis, on the anterior side of the piriformis muscle. Before it one can find a fascial blade which separates it from the sanguine and ischial vessels. The sacral plexus gives collateral branches which are then distributed to the somatic structures of the pelvic belt, but also gives a terminal branch, represented by the sciatic nerve. The sciatic nerve is the most important branch of the sacral plexus. All the components of the sacral plexus converge in order to form the sciatic nerve. After it is formed in the manner described above, the sciatic nerve leaves the pelvic subperitoneal space through the infrapiriform foramen, being situated in front of the obturator internus muscle and of the quadratus femoris muscle, and between the two gemellus muscles. It is covered by the gluteus maximus muscle. [ABSTRACT FROM AUTHOR]

Objective: The iliolumbar veins (ILVs) and their high frequency of variations are crucial to lumbosacral spine surgical interventions. Related damage during surgery may result in significant hemorrhage. Variations of ILVs are population specific but such reports are limited in the South African population. The current study examined the anatomy and variations and the tissue composition of the ILVs in South African cadavers of European descent. Methods: Following the ethical waiver: W-CBP-210401-01, Eighty-nine adult cadavers were dissected for ILVs. The variations, morphometrics, and topography of ILVs were studied. Nineteen (ten proximal, nine distal) ILVs were processed for Hematoxylin and Eosin, Masson's trichrome and Verhoeff's histological stains to determine the tissue composition. Results: ILVs were identified in 100% of cases. 45% of ILVs anastomose with each other bilaterally. Right sided ILVs terminated into posterior surfaces of the iliac vessels (p=.001), while left sided terminated into lateral surfaces (p=.001). 61% of the cadavers exhibited classification type 1 of ILVs pattern. 42% of ILVs were at S1 vertebral level with 31% lying between L4 and L5 spinal nerve roots. Left side PILVs had higher elastic fiber composition (p=.030). ILVs elastic to collagen fiber area ratio was 1:9. Conclusion: ILV variations described in this study present new additional patterns, like bilateral anastomosis and laterality of the terminal drainage and ILV lying between L4 and L5 spinal nerve roots. ILVs have more collagen fibers than elastic fibers, predisposing them to avulsion during surgical retraction. Identification of all ILVs is important to minimize inadvertent hemorrhage and injury to adjacent structures. [ABSTRACT FROM AUTHOR]

Objectives: To reveal the variations of the iliolumbar artery and the iliolumabar veins and their correlation with the surrounding important structures. Methods: We dissected the iliolumbar region bilaterally in 20 formalin-fixed adult cadavers. The diameter of the iliolumbar artery at its origin, its length up to the branching point, the distance between the iliolumbar artery and the inferior margin of the fifth lumbar vertebra and the distance between the iliolumbar artery and the bifurcation point of the common iliac artery, were measured. The pattern of drainage, the dimensions, the points of confluence with the common iliac vein and the obliquity of the iliolumbar vein were noted. The correlation between the iliolumbar artery and the veins to the obturator nerve and the lumbosacral trunk was recorded. Results: The iliolumbar artery originated from the posterior trunk of the internal iliac artery or from the internal iliac artery. The mean diameter of the iliolumbar artery, at its origin, was 3.5±0.5 mm. The mean distance between the origin of the iliolumbar artery and the bifurcation point to the iliac and the lumbar branches was 12.2±5.5 mm. The distance between the origin of the iliolumbar artery and the lower edge of the fifth lumbar vertebra was 43.2±11.6 mm. The distance between the origin of the iliolumbar artery and the bifurcation point of the common iliac artery was 38.7±10.6 mm. The mean distance of the iliolumbar veins from the inferior vena cava, overall, was 35± 9.9 mm. The mean width of the mouth of the iliolumbar vein was10.7 ± 5.1 mm and the mean angle of obliquity of the vein with respect to the long axis of the common iliac vein was 75.50. The tributaries which drained into the main iliolumbar vein were variable. The iliolumbar artery passed anterior in 70% and it passed posterior to the obturator nerve in 30%. The veins were lying anterior to the obturator nerve in 45% and they were lying posterior in 55%. The multiple tributaries which drained into the iliolumbar vein relation of the tributaries were variable, few passed anterior and few passed posterior. The iliolumbar artery was seen anterior to the lumbosacral trunk in 30%, it was posterior in 54%, it was cleaved in 8% and the branches of the artery were passing on either side of the lumbosacral trunk to enclose it like a clasp in 8%. The veins were anterior to the lumbosacral trunk in 40% and they were posterior in 60%. Conclusion: The anatomical features of the iliolumbar artery, the iliolumbar veins and their correlation with the anatomical landmarks, which were presented here, would be helpful in decreasing the iatrogenic trauma to the neurovascular structures in the iliolumbar region. [ABSTRACT FROM AUTHOR]

Background: We aimed to study the mechanism of sacral nerve injury caused by sacral fractures and the relationship between nerve decompression and nerve function. Methods: First, we observed the anatomical features of lumbosacral nerve root region in Sprague-Dawley rats. Next, the rats were divided into the sham, 10 g, 30 g, and 60 g groups for electrophysiological studies on nerve root constriction injury. Then we studied the biomechanical properties of rat nerve roots, lumbosacral trunk, and sacrum. Finally, we established a finite element analysis model of sacral nerve roots injury in rats and determined the correlation between sacral deformation and the degree of sacral nerve roots injury. Result: Anatomical study showed L5 constitutes sciatic nerve, the length of the L5 nerve root is 3.67 ± 0.15 mm, which is suitable for electrophysiological research on nerve root compression injury. After a series of electrophysiological study of L5 nerve roots, our results showed that nerve root function was almost unaffected at a low degree of compression (10 g). Nerve root function loss began at 30 g compression, and was severe at 60 g compression. The degree of neurological loss was therefore positively correlated with the degree of compression. Combining biomechanical testing of the lumbosacral nerve roots, finite element analysis and neuroelectrophysiological research, we concluded when the sacral foramina deformation is >22.94%, the sacral nerves lose function. When the compression exceeds 33.16%, early recovery of nerve function is difficult even after decompression. Conclusion: In this study, we found that the neurological loss was positively correlated with the degree of compression. After early decompression, nerve root function recovery is possible after moderate compression; however, in severe compression group, the nerve function would not recover. Furthermore, FEA was used to simulate nerve compression during sacral fracture, as well as calculate force loading on nerve with different deformation rates. The relationship between sacral fractures and neurological loss can be analyzed in combination with neurophysiological test results., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Xu, Jiang, Mu, Li, Zhang, Jiang and Xu.)

Abstract The scrotal nerves in the rat were studied electrophysiologically to describe their topographic organization in the skin and in the dorsal roots, and to determine if the electrical properties of these afferents are under the influence of testosterone. There are 2 afferent nerve branches innervating this area, the proximal scrotal branch supplying the proximal half of the scrotum (PSb), and the distal scrotal branch supplying the distal half (DSb). Results showed that afferent axons from PSb enter the spinal cord through the L5 and L6 dorsal roots, and axons from DSb enter the cord through the L6 and S1 dorsal roots. Mechanical stimulation of the scrotal skin exposed 3 dermatome areas, the L5, L6, and S1, with L6 being the longest dermatome with intermingled terminals from PSb and DSb. Decreased levels of testosterone after castration increased the threshold to trigger the activity of scrotal afferents, and the exogenous administration of the hormone reverted it. This effect was similar in the dorsal penile nerve. The decrease in androgen levels produced a reduction in the skin sensory field to mechanical stimuli that was restored after the administration of the hormone. As the scrotal nerves are highly stimulated during copulation in parallel with the dorsal penile nerve, it is suggested that the sensory field of the scrotal skin could be closely related to the modifications in sexual behavior after testosterone manipulation. [ABSTRACT FROM AUTHOR]

Variations of the peripheral nerve plexuses are important to those clinicians who diagnose and treat patients with pathology of their parts. During routine dissection, a postfixed lumbosacral plexus with a furcal nerve arising from L5, not L4, was discovered. In addition, the case was found to have a split L5 ventral ramus. Such a variation might become clinically significant during clinical presentations of radiculopathy. With a better understanding of the fucal nerve variation presented here, along with previously documented variations, the diagnostic and treatment procedures for atypical radiculopathy can be refined, reducing the rates of nerve injury and failed back surgery., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Variations in the course of the lumbar plexus and lumbosacral trunk have been explored with respect to variant nerve roots being indicated in atypical sciatic pain. Typically, the furcal nerve emerges from the L4 nerve root, with a single contribution. However, we report a case where the furcal nerve was found to arise not only from the L4 nerve but also from the obturator nerve. This anatomical variation is explored in terms of its clinical significance and implications in lumbar and sacral plexus associated procedures., (Copyright © 2020. Published by Elsevier Masson SAS.)