12th Rib Length as a Predictor of Anatomical Variations in the Lumbosacral Plexus Associated with Atypical Radiculopathy in Lumbar Disc Herniation

12th Rib Length as a Predictor of Anatomical Variations in the Lumbosacral Plexus Associated with Atypical Radiculopathy in Lumbar Disc Herniation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article 12th Rib Length as a Predictor of Anatomical Variations in the Lumbosacral Plexus Associated with Atypical Radiculopathy in Lumbar Disc Herniation Hidaka Anetai, Juri Teramoto, Takafumi Ono, Toshiaki Kiribayashi, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5812659/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 May, 2025 Read the published version in Spine → Version 1 posted You are reading this latest preprint version Abstract Study Design : A combined clinical and cadaveric observational study. Objectives : To investigate whether anatomical variations in the lumbosacral plexus (LSP) are associated with diagnostic discrepancies in lumbar disc herniation (LDH) and to corroborate clinical findings with anatomical evidence. Summary of Background Data : LDH is typically diagnosed based on clinical neurological symptoms and the level of the compressed spinal nerve root (the responsible lesion) identified by magnetic resonance imaging. However, in some patients, radiculopathy symptoms do not always align with the responsible lesion, complicating the diagnosis. This discrepancy may be linked to anatomical variations in the LSP, although the exact cause remains unclear. LSP roots may exhibit cranio-caudal deviations, which tends to be associated with shorter or longer 12th ribs, providing a potential basis for investigation. Methods : We examined 12th rib length in 144 patients with LDH at Juntendo University Hospital and investigated the relationship between LSP branch deviations and 12th rib length in 29 Japanese cadavers, donated to Juntendo University School of Medicine. Results : Of the total, 102 cases showed matching radiculopathies and responsible lesions (matched group), while 42 cases exhibited discrepancies (mismatched group). The mismatched group was subdivided into: 19 cases with radiculopathy at a lower level than predicted by the responsible lesion (lower-level radiculopathy type) and 23 cases with radiculopathy at a higher level (higher-level radiculopathy). These types were significantly associated with shorter and longer 12th ribs, respectively, suggesting cranial and caudal deviations in LSP branches, confirmed by anatomical examination. Conclusion : These findings suggest that contradictory neurological symptoms in LDH may be largely due to cranio-caudal deviations in the LSP and its branches. Furthermore, the 12th rib length may help predict these anatomical variations, potentially improving diagnostic accuracy in LDH. Orthopedic Surgery 12th rib radiculopathy lumbar disc herniation lumbosacral plexus lumbar plexus sacral plexus anatomic variation cranial deviation caudal deviation variation prediction clinical anatomy diagnosis Figures Figure 1 Figure 2 Figure 3 Figure 4 Key points 12th Rib Length as Predictor: 12th rib length may predict anatomical variations in the lumbosacral plexus (LSP) linked to atypical radiculopathy in lumbar disc herniation. LSP Variations and Radiculopathy: Anatomical variations in LSP branches are associated with atypical radiculopathy, offering diagnostic insights beyond MRI findings. Improved Diagnosis: Measuring the 12th rib length could enhance diagnostic accuracy in lumbar disc herniation when MRI results are inconclusive. Mini abstract Atypical neurological symptoms in patients with LDH that contradict MRI findings are likely caused by anatomical variations in the LSP and its branches. These variations can be predicted by the 12th rib length, offering the potential to improve diagnostic accuracy in LDH. Introduction Lumbar disc herniation (LDH) is a degenerative condition in which the lumbar intervertebral disc, including the nucleus pulposus, is displaced and protrudes into the spinal canal. Patients with LDH often experience low back pain and lumbar radiculopathy, both of which decrease quality of life and social productivity 1 , 2 . Clinical diagnosis is typically based on neurological symptoms, such as dermatomal sensory and myotomal motor abnormalities, and the height of the herniated lumbar intervertebral disc and compressed spinal nerve root (the responsible lesion) identified by magnetic resonance imaging (MRI) or computed tomography (CT) 3 , 4 . However, in some patients, observed radiculopathies contradict the neurological symptoms expected from the responsible lesion's height 5 , 6 . This discrepancy can hinder accurate diagnosis and delay appropriate surgical interventions. Identifying the cause of this discrepancy is clinically valuable. We speculate that it is related to anatomical variations in the lumbosacral plexus (LSP) and its branches. The LSP comprises the lumbar and sacral plexuses that branch into several nerves innervating the skin sensory and muscles of the pelvic and lower limb regions 7 – 9 . The lumbar plexus typically consists of the ventral rami of the 1st to 4th lumbar nerves (L1 to L4), while the sacral plexus consists of the L4 to S4 nerves. However, the origins of these plexuses and their branches occasionally deviate cranially or caudally 10 – 14 . For instance, L5 may join the femoral and obturator nerves, a phenomenon known as caudal deviation; conversely, L3 may join the sacral plexus, termed cranial deviation. These cranial and caudal deviations of the LSP roots are commonly referred to as pre-fixed and post-fixed LSPs, respectively 12 , 13 , 15 . Although these deviations in the LSP roots and their branches are speculated to potentially explain the discrepancy between observed radiculopathy and the responsible lesions in patients with LDH, their exact relationship remains unclear, as LSP roots are not accurately identifiable through routine imaging techniques 16 . A recent cadaveric study reported that cranial and caudal deviations in the lumbar plexus tend to be associated with shortening or elongation of the 12th rib, respectively 17 . This relationship has also been observed in the LSP in Japanese macaques 18 , suggesting that these anatomical patterns are not merely coincidental. Based on these anatomical findings, the 12th rib length could serve as a marker to estimate LSP deviations in patients, and help identify whether discrepancies in radiculopathy and responsible lesions in patients with LDH arise from LSP variations. If proven, evaluating LSP variation through the 12th rib length could provide insights into atypical radiculopathy in these patients. In this study, we examined the 12th rib length to estimate variations in the LSP origins in patients with LDH whose neurological symptoms either matched or mismatched the MRI evidence of the responsible lesion. Shortening or elongation of the 12th rib, associated with cranial or caudal deviations in the LSP origin, was observed in patients with LDH with contradictory symptoms. These findings suggest that the discrepancy may be attributed to variations in the LSP. Additionally, variations in the roots of all the LSP branches innervating lower limb and their relationship to 12th rib length were re-examined in human cadavers to expand on previous anatomical findings and establish more robust clinically oriented anatomical evidence. Based on these clinical and anatomical findings, we discuss their potential application in the clinical evaluation, diagnosis, and treatment of LDH. Materials and methods Clinical examinations This study included 144 patients (92 males and 52 females) diagnosed with LDH at Juntendo University Hospital between 2017 and 2022. The patients' average age was 43.99 ± 17.72 years (mean ± standard deviation). Patients with LDH with multiple herniations, cauda equina syndrome, or severe spine deformities were excluded. The protocol was approved by The Ethics Committee of the Juntendo University School of Medicine (Approval No. E21-0147-H01) and conducted in accordance with the Declaration of Helsinki (2013) for experiments involving humans. Clinical data, including age, sex, height, neurological symptoms, CT thorax images, and MRI evidence of the responsible lesion, were collected and analyzed. The 12th rib length was measured as the straight distance between its proximal costal head and distal apex on anterior CT images. Accurate measurement along the curved 12th ribs on CT was challenging due to their three-dimensional curvature. Additionally, the 12th rib length was corrected for body size differences by calculating the ratio of rib length to height. For clinical relevance, the corrected 12th rib length was determined using the formula: corrected 12th rib length = mean of height × (individual 12th rib length/height), as described in a previous study 18 . Patients were categorized into two groups: those whose neurological symptoms matched the responsible lesion on MRI and those with contradictory symptoms. In these groups, the ratio of 12th length to height were analyzed using the Kruskal–Wallis test, with Bonferroni post hoc tests applied. Statistical analyses were performed using GraphPad Prism 10 (GraphPad Software, Inc., La Jolla, CA). Statistical significance was set at p<0.05. Anatomical re-examinations We re-examined the LSP, including all its branches innervating the lower limb, and the 12th rib length in 57 sides of 29 Japanese cadavers (14 males, 15 females). The average age of the individuals was 85.06 ± 9.64 years (mean ± standard deviation). All cadavers were donated to Juntendo University School of Medicine for educational and research purposes, with written consent obtained from the individuals and their families. The protocol for this anatomical examination was approved by the Ethics Committee of the Juntendo University School of Medicine (Approval No. 2014138) and conducted in accordance with the Declaration of Helsinki and the Japanese law “Act on Body Donation for Medical and Dental Education”. Deviations in the origins of the LSP branches were examined macroscopically and recorded using digital photographs (Nikon 5600, Nikon, Japan) and line drawings. The LSP branches innervating the lower limb, including the lateral femoral cutaneous, femoral, obturator, superior gluteal, inferior gluteal, common peroneal, tibial, and posterior femoral cutaneous nerves, were analyzed. Their origins were classified into three types: typical, cranially deviated, and caudally deviated. The relationship between the origin types of the LSP branches and the 12th rib length was then analyzed by Analysis of variance (ANOVA), followed by the Bonferroni post hoc test (p<0.05). The length of the 12th rib was measured both as the actual length along the rib and as the straight-line distance (similar to CT measurements in the clinical examination) from the costal head to the distal apex. These measurements were then corrected by femur length, as femur length strongly correlates with height in humans 19 , 20 . Due to the aging process and associated spinal deformities in the cadavers, height was not used to correct for body size differences. For clinical relevance, the corrected 12th rib length was calculated as: corrected 12th rib length = (mean femur length) × (individual 12th rib length/femur length). Results Clinical examinations Our analysis included 144 patients diagnosed with LDH, with the majority having L5/S1 or L4/L5 intervertebral disc herniation. The 144 patients were initially divided into two groups based on whether the observed radiculopathies corresponded to the responsible lesions on MRI (matched group) or not (mismatched group). Matched group A total of 102 patients (62 males and 40 females) were included in the matched group. The mean age was 45.16 ± 18.24 years. The mean ratio of 12th rib length to height was 0.062 ± 0.013, and the mean corrected 12th rib length was 104.1 ± 21.73 mm (Table 1 ). Table 1 Relationship between observed radiculopathies and 12th rib length Groups & types Numbers Ratio of 12th rib length to height (mm) Corrected 12th rib length (mm) Matched group 102 0.062 ± 0.013 104.1 ± 21.73 Mismatched group Lower-level radiculopathy type 19 0.043 ± 0.02 71.46 ± 33.84 Higher-level radiculopathy type 23 0.077 ± 0.007 132.76 ± 13.21 Mismatched group In the mismatched group, 42 patients (30 males and 12 females) were included. The mean age in this group was 41.1 ± 16 years. The mismatched group was further categorized into two types of discrepancies. Nineteen of the 42 cases exhibited radiculopathy at a lower level than expected based on the level of the responsible lesion (e.g., S1 radiculopathy caused by an L5 lesion), termed the lower-level radiculopathy type. The remaining 23 cases showed radiculopathy at a higher level than predicted (e.g., L5 radiculopathy caused by an S1 lesion), termed the higher-level radiculopathy type. The mean ratio of 12th rib length to height was 0.043 ± 0.02 for the lower-level radiculopathy type and 0.077 ± 0.007 for the higher-level radiculopathy type in the mismatched group (Table 1 ). The ratio of 12th rib length was significantly longer in the higher-level radiculopathy type and shorter in the lower-level type compared to the matched group (Fig. 1 ). The mean corrected 12th rib length was 71.46 ± 33.84 mm for the lower-level radiculopathy type and 132.76 ± 13.21 mm for the higher-level radiculopathy type. Anatomical re-examinations Variations in LSP branches origin All branches arising from the LSP were examined, and their variations in origin were detailed, as summarized in Table 2 . The origin pattern with the highest frequency was classified as the typical type, while cranial- and/or caudal-deviated types were identified for each nerve. No cranial deviations were observed in the obturator and superior gluteal nerves, and no caudal deviations were found in the lateral and posterior femoral cutaneous nerves. Table 2 Anatomical variations in the LSP branches and their relation to 12th rib length Nerves Origins Numbers Type Ratio of 12th rib length to femur length (mm) Corrected 12th rib length (mm) lateral femoral cutaneous nerve L1, L2 10 cranial deviated 0.21 ± 0.07 78.64 ± 27.01 L1 ~ L3 2 L2 21 L2, L3 24 typical 0.35 ± 0.05 128.11 ± 19.87 femoral nerve L1 ~ L4 15 cranial deviated 0.18 ± 0.06 66.65 ± 21.66 L2 ~ L4 27 typical 0.28 ± 0.07 100.82 ± 24.91 L2 ~ L5 15 caudal deviated 0.37 ± 0.05 134.01 ± 17.65 obturator nerve L2 ~ L4 39 typical 0.23 ± 0.07 84.99 ± 26.88 L2 ~ L5 3 caudal deviated 0.37 ± 0.04 134.31 ± 15.54 L3, L4 9 L3 ~ L5 6 superior gluteal nerve L4 ~ S1 33 typical 0.22 ± 0.07 80.12 ± 26.06 L4 ~ S2 6 caudal deviated 0.35 ± 0.05 128.68 ± 17.46 L5, S1 4 L5 ~ S2 14 inferior gluteal nerve L4 ~ S1 1 cranial deviated 0.21 ± 0.07 74.56 ± 24.51 L5, S1 15 L5 ~ S2 39 typical 0.31 ± 0.09 110.44 ± 31.11 S1, S2 2 caudal deviated 0.32 ± 0.01 116.01 ± 4.64 common peroneal nerve L4 ~ S1 22 cranial deviated 0.19 ± 0.05 67.11 ± 18.59 L4 ~ S2 23 typical 0.32 ± 0.05 114.8 ± 18.35 L5 ~ S2 12 caudal deviated 0.37 ± 0.05 134.6 ± 18.16 tibial nerve L4 ~ S1 1 cranial deviated 0.17 ± 0.04 61.48 ± 16.09 L4 ~ S2 14 L4 ~ S3 32 typical 0.3 ± 0.06 106.58 ± 22.32 L5 ~ S3 10 caudal deviated 0.39 ± 0.05 139.91 ± 17.66 posterior femoral cutaneous nerve S1, S2 19 cranial deviated 0.24 ± 0.08 85.1 ± 29.86 S2 1 S1 ~ S3 14 S2, S3 23 typical 0.34 ± 0.06 123.42 ± 22.88 12th rib length The LSP was categorized into three types—typical, cranial-deviated, or caudal-deviated—based on the origins of its main branches, including the femoral, obturator, and lumbosacral trunk, which forms the upper part of the sacral plexus ( Fig. 2 and Supplementary Fig. 1) . The 12th rib length (and the ratio of actual 12th rib length to femur length) was significantly shorter in cranial-deviated LSPs and longer in caudal-deviated LSPs. When examining each nerve of the LSP, including the femoral, common peroneal, and tibial nerves, the 12th rib length (and its ratio to femur length) was significantly shorter in the cranial-deviated type and longer in the caudal-deviated type compared to the typical type ( Fig. 3 ) . No significant differences were found between the typical and caudal-deviated types, nor between the cranial-deviated and caudal-deviated types for the inferior gluteal nerve. The obturator and superior gluteal nerves only showed caudal deviations, and in these cases, the 12th rib length was significantly longer. Conversely, the lateral and posterior femoral cutaneous nerves showed cranial deviations only, with a significant shortening of the 12th rib. In addition, longer 12th ribs were associated with increased three-dimensional curvature, and as the 12th rib lengthened, the difference between the straight distance and the distance along the curved 12th rib also increased (Fig. 4 ). Discussion In this study, we identified a significant relationship between contradictory neurological symptoms and 12th rib length in patients with LDH. Specifically, we observed that the lower-level radiculopathy type was associated with shorter 12th ribs, while the higher-level radiculopathy type was linked to longer 12th ribs. Furthermore, our cadaveric re-examination of the LSP, with a focus on LSP branches in relation to the 12th rib length, strengthens and extends the findings of Tokita et al. (2021) 17 , offering robust support for our clinical results. Notably, in this re-examination, we conducted a detailed analysis of several branches arising from the sacral plexus in addition to the lumbar plexus branches, demonstrating for the first time that cranial and caudal deviations of the LSP and most of its branches were statistically associated with shorter or longer 12th ribs, respectively. These findings were significant in establishing a clear anatomical basis for the observed clinical discrepancies, as the L5 or S1 roots—forming upper part of the sacral plexus—were more frequently affected by L4/L5 or L5/S1 LDH. Our results indicate that higher-level radiculopathy is associated with caudal deviations in the LSP and its branches, while lower-level radiculopathy corresponds to cranial deviations. These anatomical deviations in the origins of the LSP and its branches are likely responsible for the observed discrepancy between clinical symptoms and the MRI-confirmed level of the herniated disc. These variations may substantially affect the diagnostic accuracy of LDH. Indeed, while imaging techniques for LDH are widely used, their diagnostic accuracy remains controversial 4 . Moreover, these discrepancies in symptom could lead to significant challenges in local diagnosis, potentially contributing to increased surgical invasiveness and failed back surgery syndrome 6 . If the variations in the LSP and its branches could be assessed during the diagnostic process, it would likely improve diagnostic accuracy, thereby reducing the risks of misdiagnosis and unnecessary procedures. Based on both our clinical and anatomical findings, we propose that 12th rib length could serve as a useful predictor for the anatomical variations in the LSP and its branches, as well as the related neurological symptoms in patients with LDH. The relationship between variations in the LSP, including its branches, and contradictory radiculopathies has been suggested by previous studies 21 , 22 , although the precise nature of this relationship remains largely unexplored. Earlier attempts to evaluate LSP variations in living humans through methods such as X-ray examination 23 or reflex testing 24 were not practical in routine clinical settings. In contrast, our method, based on measuring 12th rib length, offers a simpler, more accessible approach, which could be widely implemented across various medical institutions. We also observed that longer 12th ribs are associated with increased three-dimensional curvature, which suggests that the length of these ribs may often be underestimated in clinical practice. This underestimation could obscure caudal deviations of the LSP and its branches, which are linked to higher-level radiculopathy. By measuring the 12th rib length along its actual curvature—as done in our cadaveric study—this issue could be mitigated. However, this process can be labor-intensive when using CT or MRI in clinical practice. If other morphological predictors can be identified, combining them with 12th rib length may enable a more accurate estimation of caudal deviations in the LSP and its branches in patients. Elongation of the 12th rib, along with caudal deviations in the LSP and its branches, is reported to be associated with the development of a supernumerary 13th rib (an elongated costal process of the first lumbar vertebra) 17 , 18 , 25 . Bardeen (1900) noted that changes in the length of the 12th rib could correlate with variations in the thoracolumbar vertebral formula, including the thoracization of the first lumbar vertebra, lumbarization of the 12th thoracic or first sacral vertebra, sacralization of the fifth lumbar vertebra, and other transitional vertebral morphologies 26 . These relationships were long speculated to be linked to deviations in the roots of the LSP and its branches 11 , 13 , 27 , 28 , although recent precise anatomical analyses by Ishiguro et al. (2020) have disputed this connection 29 . These findings suggest that elongation of the 12th rib may be associated with additional morphological changes in the vertebral column and ribs. Consequently, we are conducting further analyses to investigate these relationships in more detail. If these morphological changes can be clearly identified, combining this information with the evaluation of 12th rib length—i.e., using a combination of multiple predictors—could allow for a more accurate estimation of caudal deviations in the LSP and its branches in patients with LDH. This would, in turn, help minimize the risk of oversight and improve diagnostic accuracy. Conclusion In this study, we have demonstrated that contradictory neurological symptoms—specifically lower or higher-level radiculopathy—are significantly associated with shorter or longer 12th ribs, respectively, in patients with LDH. Our anatomical re-examination clearly shows that a shorter 12th rib corresponds to cranial deviations in the LSP and its branches, while a longer 12th rib correlates with caudal deviations. These findings suggest that such deviations in the LSP play a crucial role in the observed neurological discrepancies in patients with LDH. Consequently, variations in the LSP and its branches can be inferred based on the 12th rib length, offering a potential tool to improve the diagnostic accuracy of LDH. However, the longer 12th ribs and associated caudal deviations may be prone to underestimation on CT; and therefore, overlooked in clinical practice. Future studies could further refine these findings by identifying additional skeletal morphological changes associated with caudal deviations. Such advancements could significantly enhance the accuracy of LDH diagnosis and improve patient outcomes. Declarations Funding information This work was supported by JSPS KAKENHI Grant number 24K20479. Acknowledgment The authors sincerely thank the patients who participated to clinical examination and the deceased who donated their bodies to science so that anatomical examination could be performed. Results from such research can potentially increase mankind's overall knowledge that can then improve patient care. Therefore, these patients, donors and their families deserve our highest gratitude. We would like to thank Mr. Naoaki Kimura and Mr. Hironori Matsuda for their technical assistance. We also would like to thank Editage (www.editage.jp) for English language editing. Ethics The protocol of the clinical and anatomical examination were both approved by The Ethics Committee of the Juntendo University School of Medicine (Approval No. E21-0147-H01 and No. 2014138) and conducted in accordance with the Declaration of Helsinki (2013) for experiments involving humans. Conflict of interest The authors declare no potential conflict of interest. References Maetzel A, Li L. The economic burden of low back pain: A review of studies published between 1996 and 2001 . Best Pract Res Clin Rheumatol 2002;16:23–30. Selim AJ, Ren XS, Fincke G, et al. The importance of radiating leg pain in assessing health outcomes among patients with low back pain. Results from the veterans health study . Spine 1998;23:470–4. Wu L, Liu L. Analysis of the application value of MRI and CT diagnosis of lumbar disc herniation . Proc Anticancer Res 2020;4. Pojskic M, Bisson E, Oertel J, et al. 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Observations on the autonomic nervous system and on vertebral and neural segmentation in monkeys . Trans Zool Soc Lond 1938;23:315–78. Bardeen CR. Costo-vertebral variation in man . Anat Anz 1900;18:377–82. Jackson C. Morris’s Treatise on Anatomy: A Complete Systematic Treatise by English and American Authors. Philadelphia: P. Blakiston's son; 1914. Kawashima T, Sato F. Prominent caudal shift of the lumbar plexus roots in spines with 18 thoracolumbar vertebrae . Surg Radiol Anat 2023;45:1245–56. Ishiguro K, Kawashima T, Sato F. The phenotypic morphology of human lumbar plexus roots associated with changes in the thoracolumbar vertebral count and trade-off . Sci Rep 2020;10:127. Additional Declarations The authors declare no competing interests. Supplementary Files FigureS1.tif Supplemental digital content 1. Supplemental Figure 1. Photographs of typical LSP (A) and schematic diagram (B). Branch origins indicated. Abbreviations: CPN, common peroneal nerve; FN, femoral nerve; IGN, inferior gluteal nerve; LFCN, lateral femoral cutaneous nerve; ON, obturator nerve; PFCN, posterior femoral cutaneous nerve; SGN, superior gluteal nerve; TN, tibial nerve. Cite Share Download PDF Status: Published Journal Publication published 21 May, 2025 Read the published version in Spine → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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Anetai","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/klEQVRIiWNgGAWjYBACAyjNw89wAMxgbIDwCWlJYOCRbABqOUCKFgYDkCUILXiAOQPzswcff9jJGB88Y/b4Q8Ud2X4G5ocfGGTu4NRi2cBmbjgjIZnH7MAZc4MDZ54Zz2xgM5Zg4HmG22H3H5hJ8yQwg7SYSRxsO5y44QCDGdAvh3FrOcD+TfpPQj2PcQNIyz+QFvZvBLTwmEkzJBzmMWAAaWkAaeEhZAtPmWRP2nEeiQPHyiTOHDtsPLOZp1giAZ9fDrBvk/hhU23PP+PwNomKmsOy/eztGz987MEdYgggcQDKYAbixJ4DuFXCAX8DMu8HMVpGwSgYBaNghAAAjo5ZDHxbg8kAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0003-4170-5595","institution":"Department of Nursing, School of Health Sciences, Tokyo University of Technology, Tokyo, Japan","correspondingAuthor":true,"prefix":"","firstName":"Hidaka","middleName":"","lastName":"Anetai","suffix":""},{"id":401001002,"identity":"abee8099-5d56-490b-91ef-35cb448a1172","order_by":1,"name":"Juri Teramoto","email":"","orcid":"","institution":"Department of Medicine for Orthopaedics and Motor Organ, Juntendo University Graduate School of Medicine, Tokyo, Japan","correspondingAuthor":false,"prefix":"","firstName":"Juri","middleName":"","lastName":"Teramoto","suffix":""},{"id":401001003,"identity":"3a28e0d2-bc0e-44fe-8fd2-ef1d1827b8ea","order_by":2,"name":"Takafumi Ono","email":"","orcid":"","institution":"Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, Tokyo, Japan","correspondingAuthor":false,"prefix":"","firstName":"Takafumi","middleName":"","lastName":"Ono","suffix":""},{"id":401001004,"identity":"1f25905d-4fba-463d-99b5-83f96f897564","order_by":3,"name":"Toshiaki Kiribayashi","email":"","orcid":"","institution":"Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, Tokyo, Japan","correspondingAuthor":false,"prefix":"","firstName":"Toshiaki","middleName":"","lastName":"Kiribayashi","suffix":""},{"id":401001005,"identity":"89706002-5f39-4a2f-b89f-5f5f6098a677","order_by":4,"name":"Hidetoshi Nojiri","email":"","orcid":"","institution":"Department of Medicine for Orthopaedics and Motor Organ, Juntendo University Graduate School of Medicine, Tokyo, Japan","correspondingAuthor":false,"prefix":"","firstName":"Hidetoshi","middleName":"","lastName":"Nojiri","suffix":""},{"id":401001006,"identity":"b58bb048-a013-4b9f-8f03-870d2176f124","order_by":5,"name":"Yukoh Ohara","email":"","orcid":"","institution":"Spine and Spinal Cord Center, Juntendo University Hospital, Tokyo, Japan","correspondingAuthor":false,"prefix":"","firstName":"Yukoh","middleName":"","lastName":"Ohara","suffix":""},{"id":401001007,"identity":"48ff0a68-ad7f-449d-a2bf-37c8f2bd9686","order_by":6,"name":"Muneaki Ishijima","email":"","orcid":"","institution":"Department of Medicine for Orthopaedics and Motor Organ, Juntendo University Graduate School of Medicine, Tokyo, Japan","correspondingAuthor":false,"prefix":"","firstName":"Muneaki","middleName":"","lastName":"Ishijima","suffix":""},{"id":401001008,"identity":"23c4cba8-c106-40d6-81a1-669dae059e10","order_by":7,"name":"Koichiro Ichimura","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIiWNgGAWjYBACNgYehgMgBj+EYmBsAFM8RGiRbABSB4jRApc0AGlEaMED+NjPHjx0s+2evPHBM2aPP1Tcke1nYH74gUHmDm6H8eQlHM5tKzbcduCMucGBM8+MZzawGUsw8DzDrUWCxwCoJYERqMVM4mDb4cQNBxjMgM49TFCL/eYGkJZ/IC3s34jSkriBAaSlAaSFh4AtPDkGh3POJSTPOHCsTOLMscPGM5t5iiUS8PhFvv2M8eecsgTb/hmHt0lU1ByW7Wdv3/jhYw/uEEMAiQNQBjMQJ/YcwK0SDvgbkHk/iNEyCkbBKBgFIwQAANbeXMt+U4dLAAAAAElFTkSuQmCC","orcid":"","institution":"Department of Anatomy and Life Structure, Juntendo University Graduate School of Medicine, Tokyo, Japan","correspondingAuthor":true,"prefix":"","firstName":"Koichiro","middleName":"","lastName":"Ichimura","suffix":""}],"badges":[],"createdAt":"2025-01-12 08:29:58","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-5812659/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5812659/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1097/BRS.0000000000005400","type":"published","date":"2025-05-22T00:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":73759617,"identity":"a1b19c89-46a5-4424-b317-65187258eae6","added_by":"auto","created_at":"2025-01-14 11:17:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":295955,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between radiculopathy type and the 12th rib length-to-height ratio. Boxplots show differences, tested using the Kruskal–Wallis test and Bonferroni post hoc test. Statistical significance: p\u0026lt;0.05.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-5812659/v1/6a990a58066dece53fc33e23.png"},{"id":73759619,"identity":"e7777f71-4e4e-4bf7-99be-2afb941b7f86","added_by":"auto","created_at":"2025-01-14 11:17:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1206028,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Diagrams of three LSP types; (B) Relationship between LSP type and 12th rib length ratio. Differences tested using ANOVA with Bonferroni post hoc test. Statistical significance: p\u0026lt;0.05. \u003cstrong\u003eAbbreviations\u003c/strong\u003e: FN, femoral nerve; LSP, lumbosacral plexus; LST, lumbosacral trunk; ON, obturator nerve.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-5812659/v1/3ecee08681c1637c8530dd7c.png"},{"id":73759618,"identity":"c8285384-8a04-4f6c-96fa-a1d61dea06fa","added_by":"auto","created_at":"2025-01-14 11:17:24","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1185023,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between origin type and the 12th rib length-to-height ratio in LSP branches. Boxplots show differences, tested using ANOVA with Bonferroni post hoc test. Statistical significance: p\u0026lt;0.05.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-5812659/v1/3d0860c6fc4a2aa9200c3190.png"},{"id":73759622,"identity":"e323a331-9637-416e-9619-f278c09b76ea","added_by":"auto","created_at":"2025-01-14 11:17:24","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":437401,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between the actual curved 12th rib length and the difference between its curved distance and straight-line distance.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-5812659/v1/f87ac16fed63759844a4abe3.png"},{"id":83502786,"identity":"5b68ac9d-8b85-4581-9019-d6948c206271","added_by":"auto","created_at":"2025-05-27 14:00:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3479566,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5812659/v1/729bfa54-b879-47b8-a60a-db895152698b.pdf"},{"id":73759624,"identity":"0658ac2b-b979-4437-a77c-c995fa2625cb","added_by":"auto","created_at":"2025-01-14 11:17:24","extension":"tif","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":4220088,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSupplemental digital content 1. \u003c/strong\u003eSupplemental Figure 1. Photographs of typical LSP (A) and schematic diagram (B). Branch origins indicated. Abbreviations: CPN, common peroneal nerve; FN, femoral nerve; IGN, inferior gluteal nerve; LFCN, lateral femoral cutaneous nerve; ON, obturator nerve; PFCN, posterior femoral cutaneous nerve; SGN, superior gluteal nerve; TN, tibial nerve.\u003c/p\u003e","description":"","filename":"FigureS1.tif","url":"https://assets-eu.researchsquare.com/files/rs-5812659/v1/72362971f988610e027f7a7d.tif"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003e12th Rib Length as a Predictor of Anatomical Variations in the Lumbosacral Plexus Associated with Atypical Radiculopathy in Lumbar Disc Herniation\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Key points","content":"\u003col start=\"1\" type=\"1\"\u003e\n \u003cli\u003e12th Rib Length as Predictor: 12th rib length may predict anatomical variations in the lumbosacral plexus (LSP) linked to atypical\u0026nbsp;radiculopathy in lumbar disc herniation.\u003c/li\u003e\n\u003c/ol\u003e\n\u003col start=\"2\" type=\"1\"\u003e\n \u003cli\u003eLSP Variations and Radiculopathy: Anatomical variations in LSP branches are associated with atypical radiculopathy, offering diagnostic insights beyond MRI findings.\u003c/li\u003e\n\u003c/ol\u003e\n\u003col start=\"3\" type=\"1\"\u003e\n \u003cli\u003eImproved Diagnosis: Measuring the 12th rib length could enhance diagnostic accuracy in lumbar disc herniation when MRI results are inconclusive.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Mini abstract","content":"\u003cp\u003eAtypical neurological symptoms in patients with LDH that contradict MRI findings are likely caused by anatomical variations in the LSP and its branches. These variations can be predicted by the 12th rib length, offering the potential to improve diagnostic accuracy in LDH.\u003c/p\u003e"},{"header":"Introduction","content":"\u003cp\u003eLumbar disc herniation (LDH) is a degenerative condition in which the lumbar intervertebral disc, including the nucleus pulposus, is displaced and protrudes into the spinal canal. Patients with LDH often experience low back pain and lumbar radiculopathy, both of which decrease quality of life and social productivity\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Clinical diagnosis is typically based on neurological symptoms, such as dermatomal sensory and myotomal motor abnormalities, and the height of the herniated lumbar intervertebral disc and compressed spinal nerve root (the responsible lesion) identified by magnetic resonance imaging (MRI) or computed tomography (CT)\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. However, in some patients, observed radiculopathies contradict the neurological symptoms expected from the responsible lesion's height\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. This discrepancy can hinder accurate diagnosis and delay appropriate surgical interventions. Identifying the cause of this discrepancy is clinically valuable. We speculate that it is related to anatomical variations in the lumbosacral plexus (LSP) and its branches.\u003c/p\u003e \u003cp\u003eThe LSP comprises the lumbar and sacral plexuses that branch into several nerves innervating the skin sensory and muscles of the pelvic and lower limb regions\u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. The lumbar plexus typically consists of the ventral rami of the 1st to 4th lumbar nerves (L1 to L4), while the sacral plexus consists of the L4 to S4 nerves. However, the origins of these plexuses and their branches occasionally deviate cranially or caudally\u003csup\u003e\u003cspan additionalcitationids=\"CR11 CR12 CR13\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. For instance, L5 may join the femoral and obturator nerves, a phenomenon known as caudal deviation; conversely, L3 may join the sacral plexus, termed cranial deviation. These cranial and caudal deviations of the LSP roots are commonly referred to as pre-fixed and post-fixed LSPs, respectively\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Although these deviations in the LSP roots and their branches are speculated to potentially explain the discrepancy between observed radiculopathy and the responsible lesions in patients with LDH, their exact relationship remains unclear, as LSP roots are not accurately identifiable through routine imaging techniques\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. A recent cadaveric study reported that cranial and caudal deviations in the lumbar plexus tend to be associated with shortening or elongation of the 12th rib, respectively\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. This relationship has also been observed in the LSP in Japanese macaques\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e, suggesting that these anatomical patterns are not merely coincidental. Based on these anatomical findings, the 12th rib length could serve as a marker to estimate LSP deviations in patients, and help identify whether discrepancies in radiculopathy and responsible lesions in patients with LDH arise from LSP variations. If proven, evaluating LSP variation through the 12th rib length could provide insights into atypical radiculopathy in these patients.\u003c/p\u003e \u003cp\u003eIn this study, we examined the 12th rib length to estimate variations in the LSP origins in patients with LDH whose neurological symptoms either matched or mismatched the MRI evidence of the responsible lesion. Shortening or elongation of the 12th rib, associated with cranial or caudal deviations in the LSP origin, was observed in patients with LDH with contradictory symptoms. These findings suggest that the discrepancy may be attributed to variations in the LSP. Additionally, variations in the roots of all the LSP branches innervating lower limb and their relationship to 12th rib length were re-examined in human cadavers to expand on previous anatomical findings and establish more robust clinically oriented anatomical evidence. Based on these clinical and anatomical findings, we discuss their potential application in the clinical evaluation, diagnosis, and treatment of LDH.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e\u003cstrong\u003eClinical examinations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study included 144 patients (92 males and 52 females) diagnosed with LDH at Juntendo University Hospital between 2017 and 2022. The patients' average age was 43.99 ± 17.72 years (mean ± standard deviation). Patients with LDH with multiple herniations, cauda equina syndrome, or severe spine deformities were excluded. The protocol was approved by The Ethics Committee of the Juntendo University School of Medicine (Approval No. E21-0147-H01) and conducted in accordance with the Declaration of Helsinki (2013) for experiments involving humans.\u003c/p\u003e\n\u003cp\u003eClinical data, including age, sex, height, neurological symptoms, CT thorax images, and MRI evidence of the responsible lesion, were collected and analyzed. The 12th rib length was measured as the straight distance between its proximal costal head and distal apex on anterior CT images. Accurate measurement along the curved 12th ribs on CT was challenging due to their three-dimensional curvature. Additionally, the 12th rib length was corrected for body size differences by calculating the ratio of rib length to height. For clinical relevance, the corrected 12th rib length was determined using the formula: corrected 12th rib length = mean of height × (individual 12th rib length/height), as described in a previous study\u003csup\u003e18\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003ePatients were categorized into two groups: those whose neurological symptoms matched the responsible lesion on MRI and those with contradictory symptoms. In these groups, the ratio of 12th length to height were analyzed using the Kruskal–Wallis test, with Bonferroni post hoc tests applied. Statistical analyses were performed using GraphPad Prism 10 (GraphPad Software, Inc., La Jolla, CA). Statistical significance was set at p\u0026lt;0.05.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAnatomical re-examinations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe re-examined the LSP, including all its branches innervating the lower limb, and the 12th rib length in 57 sides of 29 Japanese cadavers (14 males, 15 females). The average age of the individuals was 85.06 ± 9.64 years (mean ± standard deviation). All cadavers were donated to Juntendo University School of Medicine for educational and research purposes, with written consent obtained from the individuals and their families. The protocol for this anatomical examination was approved by the Ethics Committee of the Juntendo University School of Medicine (Approval No. 2014138) and conducted\u0026nbsp;in accordance with the Declaration of Helsinki and the Japanese law “Act on Body Donation for Medical and Dental Education”.\u003c/p\u003e\n\u003cp\u003eDeviations in the origins of the LSP branches were examined macroscopically and recorded using digital photographs (Nikon 5600, Nikon, Japan) and line drawings. The LSP branches innervating the lower limb, including the lateral femoral cutaneous, femoral, obturator, superior gluteal, inferior gluteal, common peroneal, tibial, and posterior femoral cutaneous nerves, were analyzed. Their origins were classified into three types: typical, cranially deviated, and caudally deviated. The relationship between the origin types of the LSP branches and the 12th rib length was then analyzed by Analysis of variance (ANOVA), followed by the Bonferroni post hoc test (p\u0026lt;0.05).\u003c/p\u003e\n\u003cp\u003eThe length of the 12th rib was measured both as the actual length along the rib and as the straight-line distance (similar to CT measurements in the clinical examination) from the costal head to the distal apex. These measurements were then corrected by femur length, as femur length strongly correlates with height in humans\u003csup\u003e19\u003c/sup\u003e\u003csup\u003e, 20\u003c/sup\u003e. Due to the aging process and associated spinal deformities in the cadavers, height was not used to correct for body size differences. For clinical relevance, the corrected 12th rib length was calculated as: corrected 12th rib length = (mean femur length) × (individual 12th rib length/femur length).\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eClinical examinations\u003c/h2\u003e \u003cp\u003eOur analysis included 144 patients diagnosed with LDH, with the majority having L5/S1 or L4/L5 intervertebral disc herniation. The 144 patients were initially divided into two groups based on whether the observed radiculopathies corresponded to the responsible lesions on MRI (matched group) or not (mismatched group).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eMatched group\u003c/h3\u003e\n\u003cp\u003eA total of 102 patients (62 males and 40 females) were included in the matched group. The mean age was 45.16\u0026thinsp;\u0026plusmn;\u0026thinsp;18.24 years. The mean ratio of 12th rib length to height was 0.062\u0026thinsp;\u0026plusmn;\u0026thinsp;0.013, and the mean corrected 12th rib length was 104.1\u0026thinsp;\u0026plusmn;\u0026thinsp;21.73 mm (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eRelationship between observed radiculopathies and 12th rib length\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eGroups \u0026amp; types\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNumbers\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRatio of 12th rib length to height (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCorrected 12th rib length (mm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMatched group\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e102\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.062\u0026thinsp;\u0026plusmn;\u0026thinsp;0.013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e104.1\u0026thinsp;\u0026plusmn;\u0026thinsp;21.73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMismatched group\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLower-level\u003c/p\u003e \u003cp\u003eradiculopathy type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.043\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e71.46\u0026thinsp;\u0026plusmn;\u0026thinsp;33.84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigher-level\u003c/p\u003e \u003cp\u003eradiculopathy type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e0.077\u0026thinsp;\u0026plusmn;\u0026thinsp;0.007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e132.76\u0026thinsp;\u0026plusmn;\u0026thinsp;13.21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eMismatched group\u003c/h2\u003e \u003cp\u003eIn the mismatched group, 42 patients (30 males and 12 females) were included. The mean age in this group was 41.1\u0026thinsp;\u0026plusmn;\u0026thinsp;16 years. The mismatched group was further categorized into two types of discrepancies. Nineteen of the 42 cases exhibited radiculopathy at a lower level than expected based on the level of the responsible lesion (e.g., S1 radiculopathy caused by an L5 lesion), termed the lower-level radiculopathy type. The remaining 23 cases showed radiculopathy at a higher level than predicted (e.g., L5 radiculopathy caused by an S1 lesion), termed the higher-level radiculopathy type.\u003c/p\u003e \u003cp\u003eThe mean ratio of 12th rib length to height was 0.043\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02 for the lower-level radiculopathy type and 0.077\u0026thinsp;\u0026plusmn;\u0026thinsp;0.007 for the higher-level radiculopathy type in the mismatched group (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The ratio of 12th rib length was significantly longer in the higher-level radiculopathy type and shorter in the lower-level type compared to the matched group (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The mean corrected 12th rib length was 71.46\u0026thinsp;\u0026plusmn;\u0026thinsp;33.84 mm for the lower-level radiculopathy type and 132.76\u0026thinsp;\u0026plusmn;\u0026thinsp;13.21 mm for the higher-level radiculopathy type.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAnatomical re-examinations\u003c/h3\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eVariations in LSP branches origin\u003c/h2\u003e \u003cp\u003eAll branches arising from the LSP were examined, and their variations in origin were detailed, as summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The origin pattern with the highest frequency was classified as the typical type, while cranial- and/or caudal-deviated types were identified for each nerve. No cranial deviations were observed in the obturator and superior gluteal nerves, and no caudal deviations were found in the lateral and posterior femoral cutaneous nerves.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAnatomical variations in the LSP branches and their relation to 12th rib length\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNerves\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOrigins\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNumbers\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eType\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eRatio of 12th rib length to femur length (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCorrected 12th rib length (mm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003elateral femoral \u003c/p\u003e \u003cp\u003ecutaneous nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL1, L2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003ecranial deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e0.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e78.64\u0026thinsp;\u0026plusmn;\u0026thinsp;27.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL1\u0026thinsp;~\u0026thinsp;L3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL2, L3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e24\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e128.11\u0026thinsp;\u0026plusmn;\u0026thinsp;19.87\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003efemoral nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL1\u0026thinsp;~\u0026thinsp;L4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ecranial deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e66.65\u0026thinsp;\u0026plusmn;\u0026thinsp;21.66\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL2\u0026thinsp;~\u0026thinsp;L4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e27\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e100.82\u0026thinsp;\u0026plusmn;\u0026thinsp;24.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL2\u0026thinsp;~\u0026thinsp;L5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ecaudal deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e134.01\u0026thinsp;\u0026plusmn;\u0026thinsp;17.65\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eobturator nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL2\u0026thinsp;~\u0026thinsp;L4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e39\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e84.99\u0026thinsp;\u0026plusmn;\u0026thinsp;26.88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL2\u0026thinsp;~\u0026thinsp;L5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003ecaudal deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e0.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e134.31\u0026thinsp;\u0026plusmn;\u0026thinsp;15.54\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL3, L4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL3\u0026thinsp;~\u0026thinsp;L5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003esuperior gluteal nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e33\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e80.12\u0026thinsp;\u0026plusmn;\u0026thinsp;26.06\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003ecaudal deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e0.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e128.68\u0026thinsp;\u0026plusmn;\u0026thinsp;17.46\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL5, S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL5\u0026thinsp;~\u0026thinsp;S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003einferior gluteal nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ecranial deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.21\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e74.56\u0026thinsp;\u0026plusmn;\u0026thinsp;24.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL5, S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL5\u0026thinsp;~\u0026thinsp;S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e39\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.31\u0026thinsp;\u0026plusmn;\u0026thinsp;0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e110.44\u0026thinsp;\u0026plusmn;\u0026thinsp;31.11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eS1, S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ecaudal deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.32\u0026thinsp;\u0026plusmn;\u0026thinsp;0.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e116.01\u0026thinsp;\u0026plusmn;\u0026thinsp;4.64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003ecommon peroneal nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ecranial deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e67.11\u0026thinsp;\u0026plusmn;\u0026thinsp;18.59\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e23\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.32\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e114.8\u0026thinsp;\u0026plusmn;\u0026thinsp;18.35\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL5\u0026thinsp;~\u0026thinsp;S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ecaudal deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e134.6\u0026thinsp;\u0026plusmn;\u0026thinsp;18.16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003etibial nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ecranial deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e61.48\u0026thinsp;\u0026plusmn;\u0026thinsp;16.09\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL4\u0026thinsp;~\u0026thinsp;S3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e32\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e106.58\u0026thinsp;\u0026plusmn;\u0026thinsp;22.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eL5\u0026thinsp;~\u0026thinsp;S3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ecaudal deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e139.91\u0026thinsp;\u0026plusmn;\u0026thinsp;17.66\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003eposterior femoral \u003c/p\u003e \u003cp\u003ecutaneous nerve\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eS1, S2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003ecranial deviated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e0.24\u0026thinsp;\u0026plusmn;\u0026thinsp;0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003e85.1\u0026thinsp;\u0026plusmn;\u0026thinsp;29.86\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eS2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eS1\u0026thinsp;~\u0026thinsp;S3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eS2, S3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e23\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etypical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e0.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e123.42\u0026thinsp;\u0026plusmn;\u0026thinsp;22.88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e12th rib length\u003c/h2\u003e \u003cp\u003eThe LSP was categorized into three types\u0026mdash;typical, cranial-deviated, or caudal-deviated\u0026mdash;based on the origins of its main branches, including the femoral, obturator, and lumbosacral trunk, which forms the upper part of the sacral plexus \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e \u003cb\u003eand Supplementary Fig.\u0026nbsp;1)\u003c/b\u003e. The 12th rib length (and the ratio of actual 12th rib length to femur length) was significantly shorter in cranial-deviated LSPs and longer in caudal-deviated LSPs.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWhen examining each nerve of the LSP, including the femoral, common peroneal, and tibial nerves, the 12th rib length (and its ratio to femur length) was significantly shorter in the cranial-deviated type and longer in the caudal-deviated type compared to the typical type \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e. No significant differences were found between the typical and caudal-deviated types, nor between the cranial-deviated and caudal-deviated types for the inferior gluteal nerve. The obturator and superior gluteal nerves only showed caudal deviations, and in these cases, the 12th rib length was significantly longer. Conversely, the lateral and posterior femoral cutaneous nerves showed cranial deviations only, with a significant shortening of the 12th rib. In addition, longer 12th ribs were associated with increased three-dimensional curvature, and as the 12th rib lengthened, the difference between the straight distance and the distance along the curved 12th rib also increased (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we identified a significant relationship between contradictory neurological symptoms and 12th rib length in patients with LDH. Specifically, we observed that the lower-level radiculopathy type was associated with shorter 12th ribs, while the higher-level radiculopathy type was linked to longer 12th ribs. Furthermore, our cadaveric re-examination of the LSP, with a focus on LSP branches in relation to the 12th rib length, strengthens and extends the findings of Tokita et al. (2021)\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e, offering robust support for our clinical results. Notably, in this re-examination, we conducted a detailed analysis of several branches arising from the sacral plexus in addition to the lumbar plexus branches, demonstrating for the first time that cranial and caudal deviations of the LSP and most of its branches were statistically associated with shorter or longer 12th ribs, respectively. These findings were significant in establishing a clear anatomical basis for the observed clinical discrepancies, as the L5 or S1 roots\u0026mdash;forming upper part of the sacral plexus\u0026mdash;were more frequently affected by L4/L5 or L5/S1 LDH.\u003c/p\u003e \u003cp\u003eOur results indicate that higher-level radiculopathy is associated with caudal deviations in the LSP and its branches, while lower-level radiculopathy corresponds to cranial deviations. These anatomical deviations in the origins of the LSP and its branches are likely responsible for the observed discrepancy between clinical symptoms and the MRI-confirmed level of the herniated disc. These variations may substantially affect the diagnostic accuracy of LDH. Indeed, while imaging techniques for LDH are widely used, their diagnostic accuracy remains controversial\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Moreover, these discrepancies in symptom could lead to significant challenges in local diagnosis, potentially contributing to increased surgical invasiveness and failed back surgery syndrome\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. If the variations in the LSP and its branches could be assessed during the diagnostic process, it would likely improve diagnostic accuracy, thereby reducing the risks of misdiagnosis and unnecessary procedures. Based on both our clinical and anatomical findings, we propose that 12th rib length could serve as a useful predictor for the anatomical variations in the LSP and its branches, as well as the related neurological symptoms in patients with LDH.\u003c/p\u003e \u003cp\u003eThe relationship between variations in the LSP, including its branches, and contradictory radiculopathies has been suggested by previous studies\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e, although the precise nature of this relationship remains largely unexplored. Earlier attempts to evaluate LSP variations in living humans through methods such as X-ray examination\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e or reflex testing\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e were not practical in routine clinical settings. In contrast, our method, based on measuring 12th rib length, offers a simpler, more accessible approach, which could be widely implemented across various medical institutions.\u003c/p\u003e \u003cp\u003eWe also observed that longer 12th ribs are associated with increased three-dimensional curvature, which suggests that the length of these ribs may often be underestimated in clinical practice. This underestimation could obscure caudal deviations of the LSP and its branches, which are linked to higher-level radiculopathy. By measuring the 12th rib length along its actual curvature\u0026mdash;as done in our cadaveric study\u0026mdash;this issue could be mitigated. However, this process can be labor-intensive when using CT or MRI in clinical practice. If other morphological predictors can be identified, combining them with 12th rib length may enable a more accurate estimation of caudal deviations in the LSP and its branches in patients.\u003c/p\u003e \u003cp\u003eElongation of the 12th rib, along with caudal deviations in the LSP and its branches, is reported to be associated with the development of a supernumerary 13th rib (an elongated costal process of the first lumbar vertebra)\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Bardeen (1900) noted that changes in the length of the 12th rib could correlate with variations in the thoracolumbar vertebral formula, including the thoracization of the first lumbar vertebra, lumbarization of the 12th thoracic or first sacral vertebra, sacralization of the fifth lumbar vertebra, and other transitional vertebral morphologies\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. These relationships were long speculated to be linked to deviations in the roots of the LSP and its branches\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e, although recent precise anatomical analyses by Ishiguro et al. (2020) have disputed this connection\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. These findings suggest that elongation of the 12th rib may be associated with additional morphological changes in the vertebral column and ribs. Consequently, we are conducting further analyses to investigate these relationships in more detail. If these morphological changes can be clearly identified, combining this information with the evaluation of 12th rib length\u0026mdash;i.e., using a combination of multiple predictors\u0026mdash;could allow for a more accurate estimation of caudal deviations in the LSP and its branches in patients with LDH. This would, in turn, help minimize the risk of oversight and improve diagnostic accuracy.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this study, we have demonstrated that contradictory neurological symptoms\u0026mdash;specifically lower or higher-level radiculopathy\u0026mdash;are significantly associated with shorter or longer 12th ribs, respectively, in patients with LDH. Our anatomical re-examination clearly shows that a shorter 12th rib corresponds to cranial deviations in the LSP and its branches, while a longer 12th rib correlates with caudal deviations. These findings suggest that such deviations in the LSP play a crucial role in the observed neurological discrepancies in patients with LDH. Consequently, variations in the LSP and its branches can be inferred based on the 12th rib length, offering a potential tool to improve the diagnostic accuracy of LDH. However, the longer 12th ribs and associated caudal deviations may be prone to underestimation on CT; and therefore, overlooked in clinical practice. Future studies could further refine these findings by identifying additional skeletal morphological changes associated with caudal deviations. Such advancements could significantly enhance the accuracy of LDH diagnosis and improve patient outcomes.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by JSPS KAKENHI Grant number 24K20479.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors sincerely thank the patients who participated to clinical examination and the deceased who donated their bodies to science so that anatomical\u0026nbsp;examination\u0026nbsp;could be performed.\u0026nbsp;Results from such research can potentially increase\u0026nbsp;mankind's overall knowledge that can then improve patient care. Therefore, these patients, donors\u0026nbsp;and their families deserve\u0026nbsp;our highest gratitude. We would like to thank Mr. Naoaki Kimura and Mr. Hironori Matsuda for their technical assistance.\u0026nbsp;We\u0026nbsp;also would\u0026nbsp;like to thank Editage (www.editage.jp) for English language editing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe protocol of the clinical and anatomical examination were both approved by The Ethics Committee of the Juntendo University School of Medicine (Approval No. E21-0147-H01 and No. 2014138) and conducted in accordance with the Declaration of Helsinki (2013) for experiments involving humans.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no potential conflict of interest.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eMaetzel A, Li L. 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Stature estimation formulae from radiographically determined limb bone length in a modern Japanese population\u003cem\u003e.\u003c/em\u003e \u003cem\u003eLeg Med (Tokyo)\u003c/em\u003e 2009;11:260\u0026ndash;6.\u003c/li\u003e\n \u003cli\u003eMahakkanukrauh P, Khanpetch P, Prasitwattanseree S, et al. Stature estimation from long bone lengths in a Thai population\u003cem\u003e.\u003c/em\u003e \u003cem\u003eForensic Sci Int\u003c/em\u003e 2011;210:279.e1\u0026ndash;7.\u003c/li\u003e\n \u003cli\u003eMatejč\u0026iacute;k V. Anatomical variations of lumbosacral plexus\u003cem\u003e.\u003c/em\u003e \u003cem\u003eSurg Radiol Anat\u003c/em\u003e 2010;32:409\u0026ndash;14.\u003c/li\u003e\n \u003cli\u003eWarner T, Tubbs RS. Lumbar plexus. In: \u003cem\u003eSurgical Anatomy of the Lateral Transpsoas Approach to the Lumbar Spine\u003c/em\u003e. Elsevier; 2020:45\u0026ndash;81.\u003c/li\u003e\n \u003cli\u003eHarshavardhana NS, Dabke HV. 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Prominent caudal shift of the lumbar plexus roots in spines with 18 thoracolumbar vertebrae\u003cem\u003e.\u003c/em\u003e \u003cem\u003eSurg Radiol Anat\u003c/em\u003e 2023;45:1245\u0026ndash;56.\u003c/li\u003e\n \u003cli\u003eIshiguro K, Kawashima T, Sato F. The phenotypic morphology of human lumbar plexus roots associated with changes in the thoracolumbar vertebral count and trade-off\u003cem\u003e.\u003c/em\u003e \u003cem\u003eSci Rep\u003c/em\u003e 2020;10:127.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"Juntendo University Graduate School of Medicine","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"12th rib, radiculopathy, lumbar disc herniation, lumbosacral plexus, lumbar plexus, sacral plexus, anatomic variation, cranial deviation, caudal deviation, variation prediction, clinical anatomy, diagnosis","lastPublishedDoi":"10.21203/rs.3.rs-5812659/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5812659/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eStudy Design\u003c/strong\u003e: A combined clinical and cadaveric observational study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjectives\u003c/strong\u003e: To investigate whether anatomical variations in the lumbosacral plexus (LSP) are associated with diagnostic discrepancies in lumbar disc herniation (LDH) and to corroborate clinical findings with anatomical evidence.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSummary of Background Data\u003c/strong\u003e: LDH is typically diagnosed based on clinical neurological symptoms and the level of the compressed spinal nerve root (the responsible lesion) identified by magnetic resonance imaging. However, in some patients, radiculopathy symptoms do not always align with the responsible lesion, complicating the diagnosis. This discrepancy may be linked to anatomical variations in the LSP, although the exact cause remains unclear. LSP roots may exhibit cranio-caudal deviations, which tends to be associated with shorter or longer 12th ribs, providing a potential basis for investigation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: We examined 12th rib length in 144 patients with LDH at Juntendo University Hospital and investigated the relationship between LSP branch deviations and 12th rib length in 29 Japanese cadavers, donated to Juntendo University School of Medicine.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: Of the total, 102 cases showed matching radiculopathies and responsible lesions (matched group), while 42 cases exhibited discrepancies (mismatched group). The mismatched group was subdivided into: 19 cases with radiculopathy at a lower level than predicted by the responsible lesion (lower-level radiculopathy type) and 23 cases with radiculopathy at a higher level (higher-level radiculopathy). These types were significantly associated with shorter and longer 12th ribs, respectively, suggesting cranial and caudal deviations in LSP branches, confirmed by anatomical examination.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e: These findings suggest that contradictory neurological symptoms in LDH may be largely due to cranio-caudal deviations in the LSP and its branches. Furthermore, the 12th rib length may help predict these anatomical variations, potentially improving diagnostic accuracy in LDH.\u003c/p\u003e","manuscriptTitle":"12th Rib Length as a Predictor of Anatomical Variations in the Lumbosacral Plexus Associated with Atypical Radiculopathy in Lumbar Disc Herniation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-14 11:17:19","doi":"10.21203/rs.3.rs-5812659/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b7fe1920-8ffb-4985-8223-d362cd2f6a86","owner":[],"postedDate":"January 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":42735832,"name":"Orthopedic Surgery"}],"tags":[],"updatedAt":"2025-05-27T14:00:50+00:00","versionOfRecord":{"articleIdentity":"rs-5812659","link":"https://doi.org/10.1097/BRS.0000000000005400","journal":{"identity":"spine","isVorOnly":true,"title":"Spine"},"publishedOn":"2025-05-22 00:00:00","publishedOnDateReadable":"May 22nd, 2025"},"versionCreatedAt":"2025-01-14 11:17:19","video":"","vorDoi":"10.1097/BRS.0000000000005400","vorDoiUrl":"https://doi.org/10.1097/BRS.0000000000005400","workflowStages":[]},"version":"v1","identity":"rs-5812659","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5812659","identity":"rs-5812659","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}