En bloc resection of ligamentum flavum with laminotomy of the caudal lamina in the minimally invasive laminectomy: surgical anatomy and technique.

OBJECTIVE: A CSF leak is a potential complication in a lumbar laminectomy. An analysis of the author's surgical experience identified inadvertent durotomies that occurred when resecting the ligamentum flavum at its insertion into the superior aspect of the caudal lamina. Anatomical analyses of the lumbar canal diameter demonstrate that the insertion point of the caudal ligamentum flavum is the most constrained area of the canal. The surgical technique was modified to eliminate the need for direct action in that anatomical region after the author compared the efficacy of piecemeal resection of the ligamentum flavum with en bloc resection with a laminotomy of the caudal lamina beyond the insertion point of the ligamentum flavum in the lumbar laminectomy. METHODS: An analysis of a single surgeon's experience managing 147 consecutive patients with lumbar stenosis who underwent single-level lumbar hemilaminectomies over a 4-year period was performed. Patients were managed with either piecemeal resection (cohort 1) or en bloc resection with a laminotomy beyond the caudal insertion (cohort 2) of the ligamentum flavum. RESULTS: Seventy-seven patients underwent piecemeal resection (cohort 1), and 70 underwent en bloc resection (cohort 2). There were 5 CSF leaks (6.4%) in cohort 1. There were no CSF leaks in cohort 2. There was a statistically significant difference in operative times between the two groups (p = 0.04), but there was no statistically significant difference in patient-reported outcomes at 6 months between the groups. CONCLUSIONS: En bloc resection of the ligamentum flavum with a laminotomy below the caudal insertion point appears to decrease the risk of a CSF leak by working beyond the most constrained diameter of the lumbar canal to release the caudal insertion of the ligamentum flavum.

Prognostic value of cervical ligamentum flavum thickness as a morphological parameter to predict cervical stenosis.

ABSTRACT: One of major causes of cervical central stenosis (CCS) is thickened change of cervical ligament flavum (CLF). The association of a morphological parameter called cervical ligament flavum thickness (CLFT) with CCS has not been reported yet. Thus, the purpose of this research was to investigate the relationship between CCS and CFJT.Data were obtained from 88 patients with CCS. A total of 87 normal controls also underwent cervical spine magnetic resonance imaging (CSMRI). All subjects underwent axial T2-weighted CSMRI. Using our picture archiving and communications system, thickness of ligament flavum of the cervical spine at C6/7 level was analyzed.The mean CLFT was 1.41 ±â€Š0.24 mm in normal subjects and 2.09 ±â€Š0.39 mm in patients with CCS. The CCS group was found to have significantly (P < .001) higher rate of CLFT than normal subjects. ROC curves were used to assess the usefulness of CLFT as a predictor of CCS. In the CCS group, the best practical cut off-point of CLFT was 1.71 mm (sensitivity = 90.9%; specificity = 90.8%), with AUC of 0.94 (95% confidence interval: 0.90--0.98).Greater CLFT values were associated with greater possibility of CCS. Thus, treating physician should carefully examine CLFT, as it can help diagnose CCS.

The Lumbar Ligamentum Flavum Does Not Have Two Layers and Is Confluent with the Interspinous Ligament: Anatomical Study with Application to Surgical and Interventional Pain Procedures.

Numerous authors over the years have reported that the lumbar ligamentum flavum has two layers. Our routine cadaveric dissections raised the question whether this understanding is correct, as we always have observed only one layer. Thus, the goal of this cadaveric study was to reevaluate the layers of the ligamentum flavum. Twenty lumbar levels from five fresh-frozen cadaveric specimens were used in this study. After dissection of the lumbar spine, the ligamentum flavum and interspinous ligament were exposed. Each lumbar level was transected through the zygapophyseal joint, and hematoxylin and eosin staining, Masson's trichrome staining and Verhoeff-van Gieson staining were performed. Continuation of the interspinous ligament and ligamentum flavum were observed invariably. There was no evidence of the existence of a two-layered ligamentum flavum. The lumbar ligamentum flavum does not consist of two layers, but is confluent instead with the interspinous ligament that attaches to the zygapophyseal joints. To convey this anatomy better, we suggest describing the lumbar ligamentum flavum as a structure that consists of interlaminar and interspinous parts. Precise knowledge of the ligamentum flavum's anatomy can be of clinical value, particularly when epidural anesthesia or lumbar puncture are performed. Clin. Anat. 32:34-40, 2019. © 2019 Wiley Periodicals, Inc.

Morphohistometric study of the ligamentum flavum in cervical, thoracic and lumbar vertebrae: comparative approach

Anatomic characterization and fine structure of the human ligamentum flavum (LF), especially at different spinal levels, represent an attractive focus for the scientific and surgical application. Descriptive anatomical and structural study of LF at the cervical, thoracic and lumbar levels of the vertebral column in human cadavers is carried out here. The aim of the work is to clarify the anatomical features and fine structural differences in the human LF at different vertebral levels (cervical, thoracic and lumbar). Specimens of vertebral column were obtained from 34 human preserved cadavers. Their average age ranged between 56 and 69 years. Morphometric parameters including height, width and thickness of the ligament flavum at the midlevels of cervical, thoracic and lumbar regions were measured. Sections obtained from different levels were stained with different stains. Morphometric measurements involved the relative elastic area, relative collagen area, elastic area and collagen area% were measured.The results of the height, width and thickness of the LF at different spinal levels showed gradual increase in their mean values respectively. The LF midline gaps were found in the cervical, thoracic and lumbar regions. The morphometrical measurements showed that the average elastic area was highest in the cervical region and lowest in the thoracic region. In the lumbar region, the percentages of both elastic area and the collagen area were nearly the same. The characterization of morphological and histological aspects of the LF at different spinal levels will be of great importance for applications in spinal surgery, biomechanical and physical rehabilitation of vertebral column

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Anatomical analysis of the human ligamentum flavum in the thoracic spine: Clinical implications for posterior thoracic spinal surgery.

BACKGROUND: Knowledge of the ligamentum flavum anatomy is important for posterior spinal surgery. However, only a few studies have evaluated the relationship between the thoracic ligamentum flavum and its surrounding structures. This study aimed to clarify the anatomy of the thoracic ligamentum flavum. METHODS: The entire spines from 20 human embalmed cadavers were harvested in an en bloc fashion. All pedicles were vertically cut using a thread bone saw, and the ligamentum flavum from T1-T2 to T12-L1 was painted using a contrast agent containing an iron powder. Computed tomography was performed, and the ligamentum flavum shape (width and height) and its relationship with the spinal bony structures (lamina and foramen height percentage covered by the ligamentum flavum) were analyzed using a three-dimensional analyzing software. RESULTS: The thoracic ligamentum flavum height and width gradually increased from T1-T2 to T12-L1. The caudal lamina height ventrally covered by the ligamentum flavum also increased gradually from the upper (T1-T2: 31.7%) to the lower levels (T12-L1: 41.7%); however, the cranial lamina height dorsally covered by the ligamentum flavum decreased from the upper (12.6%) to the lower levels (4.3%). The neural foramen was covered by the ligamentum flavum in all thoracic spines, except for T1-T2. Between T2-T3 and T12-L1, approximately 50% of the cranial part of the foramens was covered by the ligamentum flavum; however, the caudal part was not covered. CONCLUSIONS: This study using contrasted ligamentum flavum and reconstructed CT provided information on the thoracic ligamentum flavum shape and its relationship with the bony structures. The ventral ligamentum flavum coverage of the cranial lamina increase from cranial to caudal, and the cranial half of the neural foramen is covered by the ligamentum flavum below T2-T3 but not in T1-T2. These findings would help spine surgeons to design and perform safe and adequate posterior thoracic spinal surgeries.

The posterior epidural ligament in the thoracic region: a cadaveric and histological study.

The existence of posterior epidural ligaments (PEL) has been established in the lumbar region, but they have hitherto not been shown to exist in the thoracic vertebral column. Their identification is of clinical significance in respect to incidental durotomy and the circulation of cerebrospinal fluid (CSF). Fourteen thoracic spine sections were dissected by cutting through the intervertebral disc and separating the ligamentum flavum from the vertebra above. The dural sheath was gently retracted anteriorly to identify macroscopic connections between the ligamentum flavum and the dura. Macroscopic connections observed were dissected out, retaining some dural sheath and ligamentum flavum. Histological staining with haematoxylin and eosin and Miller's elastin stain was used to investigate cellular connections. Thoracic PELs were positively identified in 5 of the 14 cadavers (35.7%). Histology showed similarities between the thoracic and lumbar PELs. Fifteen separate PELs were identified within these five thoracic sections. The thoracic PEL has sufficient tensile strength to present a risk to the integrity of the dural sheath during surgery, and surgeons should be aware of these connections when operating on the thoracic spine. PELs may also contribute to the circulation of CSF in the spinal subarachnoid space.

Anatomical analysis of human ligamentum flavum in the cervical spine: Special consideration to the attachments, coverage, and lateral extent.

BACKGROUND: Posterior decompression surgeries of cervical spine such as laminoplasty and laminoforaminotomy are well established and increasing in aging population. The anatomical knowledge of cervical ligamentum flavum (LF) is critical to perform posterior spinal surgeries, however, few studies have evaluated it, especially the relation of LF and neural foramen. METHODS: The whole spine was removed en bloc from 15 formalin-embalmed human cadavers and then divided into two segments along the pedicle bases. A total of 90 LFs from C2-C3 to C7-T1 were measured manually from the ventral side before being painted with iron powder containing contrast agent and scanned by computed tomography. We recorded dimensions, coverage of adjacent laminae, and the relationships between LF and neural foramen or facet joints. Three-dimensional CT data was used to evaluate manually limited areas and make reconstructed images. RESULTS: LF height gradually increased from C2-C3 to C7-T1, and gradually decreased from medial to lateral within each level. LF width and thickness were relatively constant from cranial to caudal. The laminar surface covered by LF gradually increased from 33% in para midline and 30% laterally at C2, and increased to 70% in para midline and 47% laterally at C6, this trend was not completed at C7. The empty zone of the laminar surface (without LF coverage) was located at the upper half of each lamina; this zone gradually decreased from cranial to caudal. The craniomedial side of the cervical facet joint was covered by a mean 4.6 ± 0.7 mm of LF, however, LF did not enter the cervical neural foramen. CONCLUSIONS: LF did not enter the neural foramen in cervical spine unlike lumbar spine. This information might be critical to avoid neurological deterioration after cervical laminoplasty or laminoforaminotomy. Surgeons would imagine the attachments and coverage of LF and its relation to posterior bony structures to perform safe posterior cervical surgeries.

Anatomical analysis of the relation between human ligamentum flavum and posterior spinal bony prominence.

BACKGROUND: Posterior spinal bony prominences are commonly used as landmarks during posterior spinal surgery; however, the exact relationship of these structures with ligamentum flavum (LF) borders and attachments has not been clarified. MATERIALS AND METHODS: Whole spines were removed en bloc from 20 embalmed human cadavers. Plain radiographs and computed tomography (CT) scans of each whole spine were taken, and then the spine was divided in two parts along the pedicle bases. The LFs were painted with contrast dye, and second radiographs and CT scans were taken again. Radiographic data were analyzed using CT image analyzer. RESULTS: The craniolateral border of LF at four upper lumbar levels (from L1/2 to L4/5) located cranial to isthmus in both sides (3.5 mm), meanwhile, it located at or below isthmus in both sides at L5-S1 level (0.5 mm). In the midline, LF attached below the isthmus levels at four upper lumbar levels (4 mm), though it located in the same level of isthmus at L5-S1 (1 mm). The mean distance between medial border of pedicles and lateral border of LF increased from upper to the lower lumbar levels (6.5 mm at L1/2 - 11.4 mm at L5-S1). Distance between interlaminar space and cranial border of LF at the midline gradually increased from 8.2 mm at L1 toward 11.1 mm at L4, it was 9.3 mm in L5. CONCLUSIONS: From the data of new analytical method using contrasted LF and reconstructed CT, the detailed relations between bony prominence and the border of LF were uncovered. Based on these findings and reconstructed LF images superimposed on lamina, surgeons would design safe and adequate lumbar spinal decompression with imagination of overall pictures of the LF from the dorsal side.

Human Lumbar Ligamentum Flavum Anatomy for Epidural Anesthesia: Reviewing a 3D MR-Based Interactive Model and Postmortem Samples.

The ligamentum flavum (LF) forms the anatomic basis for the loss-of-resistance technique essential to the performance of epidural anesthesia. However, the LF presents considerable interindividual variability, including the possibility of midline gaps, which may influence the performance of epidural anesthesia. We devise a method to reconstruct the anatomy of the digitally LF based on magnetic resonance images to clarify the exact limits and edges of LF and its different thickness, depending on the area examined, while avoiding destructive methods, as well as the dissection processes. Anatomic cadaveric cross sections enabled us to visually check the definition of the edges along the entire LF and compare them using 3D image reconstruction methods. Reconstruction was performed in images obtained from 7 patients. Images from 1 patient were used as a basis for the 3D spinal anatomy tool. In parallel, axial cuts, 2 to 3 cm thick, were performed in lumbar spines of 4 frozen cadavers. This technique allowed us to identify the entire ligament and its exact limits, while avoiding alterations resulting from cutting processes or from preparation methods. The LF extended between the laminas of adjacent vertebrae at all vertebral levels of the patients examined, but midline gaps are regularly encountered. These anatomical variants were reproduced in a 3D portable document format. The major anatomical features of the LF were reproduced in the 3D model. Details of its structure and variations of thickness in successive sagittal and axial slides could be visualized. Gaps within LF previously studied in cadavers have been identified in our interactive 3D model, which may help to understand their nature, as well as possible implications for epidural techniques.

Anatomic study and clinical significance of the dorsal meningovertebral ligaments of the thoracic dura mater.

STUDY DESIGN: A dissection-based study of 18 embalmed thoracic specimens. OBJECTIVE: To investigate the properties and clinical significance of the dorsal meningovertebral ligaments of the thoracic dura mater. SUMMARY OF BACKGROUND DATA: Previously, we performed a comprehensive anatomic study on the dorsal meningovertebral ligaments in the lumbosacral and cervical regions, whereby we concluded that the ligaments were an anatomic factor leading to dural laceration and hemorrhage during flavectomy and laminectomy. Unfortunately, thus far, no systematic anatomic study has been undertaken to examine the dorsal meningovertebral ligaments of the thoracic dura mater. METHODS: Eighteen adult embalmed cadavers were studied, and the morphology, orientation, attachment site, and distribution traits of the dorsal meningovertebal ligaments were observed. In addition, the length, width, or diameter and thickness of the ligaments were measured using a Vernier caliper. Two meningovertebal ligaments were removed for histological examination. RESULTS: In the thoracic region, the dorsal meningovertebral ligaments anchored the dura mater to the lamina or ligamentum flavum. The meningovertebral ligaments displayed a relatively even distribution along the upper thoracic region (T1-T7) and a gradual increase in frequency in the lower thoracic region from T7 to T12. The meningovertebral ligaments protrude into the dura and correspondingly become an integral part of the dura. Some ligaments are accompanied by or are attached to blood vessels. Histological examination of the meningovertebral ligaments revealed fibrous connective tissue. CONCLUSION: The dorsal meningovertebral ligaments exist between the dural sac and ligamentum flavum or lamina in the thoracic spine. Based on their anatomic features, meningovertebral ligaments may be one potential cause for dural laceration and epidural hemorrhage. We propose that, during thoracic flavectomy and laminectomy, the meningovertebral ligaments should first be identified and properly handled, thereby minimizing the occurrence of relevant complications. LEVEL OF EVIDENCE: N/A.

Development of an ultrasound phantom for spinal injections with 3-dimensional printing.

BACKGROUND AND OBJECTIVES: This report describes a method for producing anatomically detailed, low-cost ultrasound phantoms of the spine with 3-dimensional printing. An implementation that involves representing a portion of the lumbar spine and the ligamentum flavum with 2 different printing materials and the surrounding soft tissues with agar gel is presented. METHODS: A computed tomography image volume of a patient with normal spinal anatomy was segmented to isolate the spine. Segments representing the ligamentum flavum and a supporting pedestal were digitally added, and the result was printed with a 3-dimensional printer. The printed spine was embedded in agar gel as a soft tissue component. Ultrasound images of the phantom were acquired and compared with those acquired from a human patient. RESULTS: The sonographic appearances of the phantom compared favorably with those observed from the human patient. The soft tissue component was suitable for needle insertions and could be remade replacing the agar. CONCLUSIONS: Ultrasound phantoms that are derived directly from patient anatomy have strong potential as learning tools for ultrasound-guided spinal insertions, and they could be used as preprocedural planning tools in cases involving pathologies, implants, or abnormal anatomies. Three-dimensional printing is a promising method for producing low-cost phantoms with designs that can be readily shared across clinical institutions.

Anatomical characteristics of infra-lamina ridge in Chinese population / Características anatómicas del puente infra-laminar en la población china

The aim of our study was to observe the occurrence rate and morphological characteristics of Infra-Lamina ridge (ILR) in Chinese population and provide a comprehensive reference for its clinical implication. Vertebrae columns of 82 sets of Chinese adult skeletons were collected. The shape of ILR was classified into three types; the occurrence of it in different sides and sexes were counted. The length, width, thickness of ILR were measured using a caliper with 0.02 mm accuracy. The ILR was usually found to occur from C7 to L5, with its frequency higher from T8 to 12, and highest at T10being up to 80.5%. There was significant statistical difference to the occurrence rate by side, sex and vertebral level. The largest values in its length and width were from T9 to T12. The ILR at T10 was largest in dimensions, being 4.1±2.1 mm in length and 4.4±2.3 mm in width. The ILR is more frequently detected in female and at the left side, at the lower thoracic spine with a larger dimension.

El objetivo de nuestro estudio fue observar la tasa de incidencia y características morfológicas del puente infra-laminar (PIL) en la población china y ofrecer una referencia completa por su implicación clínica. Se utilizaron 82 series de vértebras pertenecientes a esqueletos adultos chinos. La forma del PIL se clasificó en tres tipos; además se cuantificó la presenciade la misma en diferentes lados y sexos. La longitud, ancho y grosor del PIL se midieron utilizando un caliper con 0,02 mm de precisión. Se encontró que el PIL por lo general se producía desde C7 a L5 , con una mayor frecuencia entre T8 y T12, la más alta en T10 donde alcanzó el 80,5%. No hubo diferencia estadísticamente significativa en la tasa de ocurrencia según lado, sexo y el nivel de la vértebra. Los mayores valores de longitud y ancho fueron de T9 a T12. El PIL en T10 tuvo las mayores dimensiones, con una longitud de 4,1±2,1 mm y ancho de 4,4±2,3 mm. El PIL se detecta con mayor frecuencia en mujeres y la lado izquierdo, con una mayor dimensión en la columna torácica inferior.

The morphology and clinical significance of the dorsal meningovertebra ligaments in the cervical epidural space.

BACKGROUND CONTEXT: The dural sac is anchored within the vertebral canal by connective tissue called meningovertebral ligaments in the epidural space. During flavectomy and laminectomy, inadvertent disruption of the dorsal meningovertebral ligaments may lead to dura laceration and cerebrospinal fluid (CSF) leaks. All the described dorsal meningovertebral ligaments were located in the lumbar region. A rare study is available about dorsal meningovertebral ligaments of the cervical spinal dura to the adjacent vertebrae. PURPOSE: To identify and describe the dorsal meningovertebral ligaments at each cervical level and discuss their clinical significance. STUDY DESIGN: A dissection-based study of 22 embalmed cadavers. METHODS: The anatomy was studied in 22 whole cervical cadavers (11 females, 11 males), prepared with formaldehyde, whose ages at the time of death ranged from 55 to 78 years. The vertebral canal was divided to expose the dural sac and the spinal nerve roots. At all levels of the cervical vertebra, the morphology, quantity, origin, insertion, and spatial orientation of the dorsal meningovertebral ligaments were determined and the length, width or diameter, and thickness of the ligaments were measured with vernier calipers. RESULTS: The dorsal meningovertebral ligaments in the cervical region anchored the posterior dural sac to the ligamentum flavum or laminae. The number of attachment points on the ligamentum flavum was relatively larger than that on the lamina, and the occurrence rate of dorsal meningovertebral ligaments was 100% at C1-C2 and C4--C5. The thickest ligaments were observed at the C1 and C2 vertebrae. The length of the ligaments varied from 1.50 to 35.22 mm, and the orientation of the ligaments mostly was craniocaudal. The morphology of the dorsal meningovertebral ligaments was divided into four types: strip type, cord type, grid type, and thin slice type. CONCLUSIONS: In the cervical spine, the dorsal meningovertebral ligaments exist between the posterior dural sac and the ligamentum flavum or lamina. The dorsal meningovertebral ligaments may be of clinical importance to surgeons. Dissecting the dorsal meningovertebral ligaments before the cervical flavectomy and laminectomy may be an important step in reducing postoperative dura laceration and CSF leaks, which may result in significant benefits for patients and health-care organizations.

Lateral extent and ventral laminar attachments of the lumbar ligamentum flavum: cadaveric study.

BACKGROUND CONTEXT: Cadaveric descriptions of the deep layer of the lumbar ligamentum flavum (LF), extending between contiguous borders of adjacent laminae and into the lateral spinal canal region are limited. PURPOSE: To provide detailed descriptions of the lumbar LF. STUDY DESIGN: Cadaveric dissection. METHODS: The deep ligamentum flava of 14 formalin-fixed human cadaver lumbar spines (140 levels) were examined to assess their laminar attachments and lateral extents in relation to the intervertebral foramen. RESULTS: The variable attachment of the deep layer of the LF with respect to the cephalad and caudad laminae was identified and described. At each successive caudal level of the lumbar spine, the deep layer appeared to become a more prominent feature of the posterior vertebral column, lining more of the laminae to which it is attached and encroaching further into the posteroinferior region of the intervertebral foramen at its lateral margins. CONCLUSIONS: We describe our observations of the deep LF in the human lumbar spine. These observations have clinical relevance for the interpretation of radiologic imaging and the performance of adequate decompression in the setting of spinal stenosis.

Lumbar ligamentum flavum: spatial relationships to surrounding anatomical structures and technical description of en bloc resection.

BACKGROUND: One structure, the ligamentum flavum, nearly always encountered in lumbar spinal operations, has not been examined as an important anatomical landmark. In this context, we describe its relevance in corridors of small surgical exposures created by minimally invasive spinal approaches. MATERIAL AND METHODS: In cadaveric and intraoperative dissections, we introduce a systematic technique for resection of this ligament and clarify its anatomical relationships with the exiting nerve roots, pedicles, facet capsule, and midline epidural fat. Fixed human cadaveric spines were harvested en bloc to maintain the lower thoracic to sacral segments. A single coronal cut through the anterior portion of the pedicles ensured that the dorsal elements were intact. Viewed from the operative microscope, photographs depict the ligamentum flavum at various intraoperative steps. RESULTS: The ligamentum flavum can undergo safe en bloc sequential resection that widely exposes the disc space for discectomy and interbody fusion. Its superolateral and inferolateral attachments are identifiable landmarks, effective in locating the exiting nerve roots. Corners of the L4-L5 ligamentum flavum mark the axillae of the exiting nerve roots (i.e., its superolateral corner marks the axilla of the L4 nerve roots, and its inferolateral corner marks the shoulder of the L5 nerve roots). CONCLUSION: Our cadaveric and microscopic surgical dissections show the ligamentum flavum as seen in the new corridors of small surgical exposures during minimally invasive surgeries of the lumbar spine. Identifying this landmark, surgeons can envision the location of the nerve roots to help prevent their injury.

Effect of table tilt on ligamentum flavum length measured using ultrasonography in pregnant women*.

The purpose of this study was to assess whether applying dorsal table tilt to a seated parturient positioned for neuraxial anaesthesia (i.e. facing laterally with her legs over the side of the table) increased the size of the target area for the neuraxial needle. We performed lumbar ultrasonography on 20 pregnant women with the table level (0°) and tilted 8° and 15° dorsally. For each position, the size of the 'target area', defined as the visible length of the ligamentum flavum in the longitudinal paramedian view, and the interlaminar distance, were measured at the L3-4 interspace. There were significant increases in the mean (SD) size of the target area with increasing table tilt (10.7 (1.3) mm at 0°, 11.5 (1.3) mm at 8° and 12.2 (1.7) mm at 15°; p < 0.0001). Interlaminar distances were not significantly increased. These data show that using dorsal table tilt in obstetric patients increases the target area for neuraxial needles. Additional research is required to assess whether this eases the placement of neuraxial needles in clinical practice.

The morphology and clinical significance of the dorsal meningovertebra ligaments in the lumbosacral epidural space.

STUDY DESIGN: A dissection-based study of 30 embalmed cadavers. OBJECTIVE: To determine the morphology and morphometry of the dorsal meningovertebral ligaments in the lumbosacral segments and to discuss their clinical significance. SUMMARY OF BACKGROUND DATA: Postoperative cerebrospinal fluid leakage is associated with longer hospital stays and significant implications for the patient, the surgeons, and society as a whole. To protect the dural sac during lumbar surgery, knowledge of the surgical anatomy of the dorsal meningovertebral ligaments is crucial. METHODS: A total of 30 adult embalmed cadavers (52-70 yr of age; mean age of 64 yr) were used. The vertebral canal was divided to expose the dural sac and the spinal nerve roots, and the spinal cord was removed. The morphology, quantity, and attachment of the dorsal meningovertebral ligaments in the lumbosacral region were observed, and the length, width, or diameter and thickness of the ligaments were measured with vernier calipers. RESULTS: The dorsal meningovertebral ligaments in the lumbosacral region connect the dura to the ligamenta flava or the lamina. The number of the attachment points on the ligamenta flava was relatively larger than that on the lamina, and the occurrence rate of dorsal meningovertebral ligaments was 97% at L5-S1. The thickest ligaments were observed at the L5 and S1 vertebrae. The length of the ligaments varied from 5.16 to 40.24 mm, and the ligaments extended caudally from their origin on the dura to their attachment to the lamina or the ligamentum flavum. The morphology of the dorsal meningovertebral ligaments was divided into 5 types: strip type, cord type, "Y"-shaped type, grid type, and thin slice type. CONCLUSION: The dorsal meningovertebral ligaments may contribute to dura laceration and epidural hemorrhage during flavectomy and laminectomy, and an appreciation of this relationship might help reduce the risk of such complications.