Lumbar Intervertebral Foramen Research Articles

Classification of Osteophytes Occurring in the Lumbar Intervertebral Foramen.

Surgeons have limited knowledge of the lumbar intervertebral foramina. This study aimed to classify osteophytes in the lumbar intervertebral foramen and to determine their pathoanatomical characteristics, discuss their potential biomechanical effects, and contribute to developing surgical methods. We conducted a retrospective, non-randomized, single-center study involving 1224 patients. The gender, age, and anatomical location of the osteophytes in the lumbar intervertebral foramina of the patients were recorded. Two hundred and forty-nine (20.34%) patients had one or more osteophytes in their lumbar 4 and 5 foramina. Of the 4896 foramina, 337 (6.88%) contained different types of osteophytes. Moreover, four anatomical types of osteophytes were found: mixed osteophytes in 181 (3.69%) foramina, osteophytes from the lower endplate of the superior vertebrae in 91 (1.85%) foramina, osteophytes from the junction of the pedicle and lamina of the upper vertebrae in 39 foramina (0.79%), and osteophytes from the upper endplate of the lower vertebrae in 26 (0.53%) foramina. The L4 foramen contained a significantly higher number of osteophytes than the L5 foramen. Osteophyte development increased significantly with age, with no difference between males and females. The findings show that osteophytic extrusions, which alter the natural anatomical structure of the lumbar intervertebral foramina, are common and can narrow the foramen.

Clinical efficacy and imaging analysis of oblique lateral lumbar interbody fusion in the treatment of different types of lumbar intervertebral foramen stenosis

PurposeTo analyze and study the clinical efficacy and imaging indexes of oblique lateral lumbar interbody fusion (OLIF) in the treatment of lumbar intervertebral foramen stenosis(LFS) caused by different causes.Method33 patients with LFS treated with OLIF from January 2018 to May 2022 were reviewed. Oswestry Dysfunction Index (ODI) and visual analogue scale (VAS) were calculated before and after operation. Segmental lordotic angle (SLA), lumbar lordotic angle (LLA) and segmental scoliosis angle (SSA), disc height (DH), posterior disc height (PDH), lateral disc height (LDH), foraminal height (FH), foramen width (FW) and foraminal cross-sectional area (FSCA) were measured before and after operation.ResultThe VAS and ODI after operation were significantly improved as compared with those before operation. Compared with pre-operation, the DH, PHD increased by 67.6%, 94.6%, LDH increased by 107.4% (left), 101.7% (right), and FH increased by 30.2% (left), 34.5% (right). The FSCA increased by 93.1% (left), 89.0% (right), and the FW increased by 137.0% (left), 149.6% (right). The postoperative SSA was corrected by 74.5%, the postoperative SLA, LLA were corrected by 70.2%, 38.1%, respectively. All the imaging indexes were significantly improved (p < 0.01).ConclusionThe clinical efficacy and imaging data of OLIF in the treatment of LFS caused by low and moderate lumbar spondylolisthesis, intervertebral disc bulge and reduced intervertebral space height, degenerative lumbar scoliosis, articular process hyperplasia or dislocation have been well improved. OLIF may be one of the better surgical treatments for LFS caused by the above conditions.

Morphometric MRI analysis of lumbar spine intervertebral foramen

The article presents morphometric MRI-analysis of the lumbar intervertebral foramen for anatomical study of the size of Kambin safety triangle and the vulnerability of the exiting spinal nerve during transforaminal interventions. 200 discs were studied in 50 patients after transforaminal endoscopic intervention. Standard DICOM image viewing program for MRI in T1 WI and T2 WI modes was used for the measurement. The most distant location of the exiting spinal nerve from the intervertebral disc was observed at the level of L5S1 vertebrae (9.82 mm, 0.95CI (9,53 10,10), p&lt;0.05). The narrowest safety triangle turned out to be at the level of L2‑L5 vertebrae, where the distance did not differ statistically (1.97–2.28 mm, p&gt; 0.05). A similar pattern was revealed for the distance between the exiting root and the intervertebral joint. The greatest angle between the exiting spinal nerve and the disc plane was found at the level of L5S1 (134.68 °, 0.95CI (132.39 136.97), p&lt;0.001). The angle was close to a straight one at the other levels. The exiting root located dorsal to the disc plane at the cranial levels (L2L3, L3L4) in all cases, in contrast to L5S1 level, where it always located ventrally. Thus, the greatest narrowness of the Kambin safety triangle was revealed in the intervertebral foramen of the cranial lumbar segments (L2L3, L3L4). Transforaminal interventions require special attention to the exiting spinal nerve at these levels, and possibly additional bone resection to widen the foramen.

Changes in the lumbar intervertebral foramen between supine and standing posture in patients with adult spinal deformity: a study with upright computed tomography.

To quantitatively assess the impact of supine and standing positions on the morphological changes in the lumbar intervertebral foramen (LIF) in patients with adult spinal deformity (ASD) using upright CT and conventional supine CT. Thirty patients with ASD were prospectively enrolled in this study. All subjects underwent standing whole spine posterior/anterior radiographs, lateral radiographs, and whole spine CT, both in the supine and upright standing positions. Two orthopedic surgeons independently measured nine radiographic parameters in the radiograph and the lumbar foraminal area (FA) and height (FH) in supine and upright CT. Statistical analyses were performed to evaluate the risk of LIF decrease when standing upright compared to the supine position. The chi-squared, t test, Pearson's coefficients, intra- and inter-rater reliabilities, and ROC curves were calculated. The level of significance was set at p < 0.05. Among the 300 LIFs, both the lumbar FA and FH were either increased or decreased by > 5% in approximately 30% of LIFs each. The FA decreased in the lower lumbar spine. The concave side had a significantly higher rate of decreased FA and FH than the convex side (p < 0.05 and < 0.05, respectively). ROC analysis showed that narrowing of the intervertebral disc (cutoff > 0.05°) is a risk factor for decreased FA and FH. This study describes the details of the changes in the neuroforamen using a novel upright CT. In patients with ASD, approximately 30% of LIFs either increased or decreased in size by > 5% when standing. The risk factors for LIF decrease are the lower lumbar spine, concave side, and narrow side of the disc wedge.

Automated Magnetic Resonance Image Segmentation of Spinal Structures at the L4-5 Level with Deep Learning: 3D Reconstruction of Lumbar Intervertebral Foramen.

Objective3D reconstruction of lumbar intervertebral foramen (LIVF) has been beneficial in evaluating surgical trajectory. Still, the current methods of reconstructing the 3D LIVF model are mainly based on manual segmentation, which is laborious and time‐consuming. This study aims to explore the feasibility of automatically segmenting lumbar spinal structures and increasing the speed and accuracy of 3D lumbar intervertebral foramen (LIVF) reconstruction on magnetic resonance image (MRI) at the L4‐5 level.MethodsA total of 100 participants (mean age: 42.2 ± 14.0 years; 52 males and 48 females; mean body mass index, 22.7 ± 3.2 kg/m2), were enrolled in this prospective study between March and July 2020. All participants were scanned on L4‐5 level with a 3T MR unit using 3D T2‐weighted sampling perfection with application‐optimized contrast with various flip‐angle evolutions (SPACE) sequences. The lumbar spine's vertebra bone structures (VBS) and intervertebral discs (IVD) were manually segmented by skilled surgeons according to their anatomical outlines from MRI. Then all manual segmentation were saved and used for training. An automated segmentation method based on a 3D U‐shaped architecture network (3D‐UNet) was introduced for the automated segmentation of lumbar spinal structures. A number of quantitative metrics, including dice similarity coefficient (DSC), precision, and recall, were used to evaluate the performance of the automated segmentation method on MRI. Wilcoxon signed‐rank test was applied to compare morphometric parameters, including foraminal area, height and width of 3D LIVF models between automatic and manual segmentation. The intra‐class correlation coefficient was used to assess the test‐retest reliability and inter‐observer reliability of multiple measurements for these morphometric parameters of 3D LIVF models.ResultsThe automatic segmentation performance of all spinal structures (VBS and IVD) was found to be 0.918 (healthy levels: 0.922; unhealthy levels: 0.916) for the mean DSC, 0.922 (healthy levels: 0.927; unhealthy levels: 0.920) for the mean precision, and 0.917 (healthy levels: 0.918; unhealthy levels: 0.917) for the mean recall in the test dataset. It took approximately 2.5 s to achieve each automated segmentation, far less than the 240 min for manual segmentation. Furthermore, no significant differences were observed in the foraminal area, height and width of the 3D LIVF models between manual and automatic segmentation images (P > 0.05).ConclusionA method of automated MRI segmentation based on deep learning algorithms was capable of rapidly generating accurate segmentation of spinal structures and can be used to construct 3D LIVF models from MRI at the L4‐5 level.

Potential Application of MR-MR-US Fusion Imaging Navigation with Needle Tail Intelligent Positioning in Guiding Puncture in Percutaneous Transforaminal Endoscopic Discectomy.

This study sought to investigate the feasibility of using magnetic resonance-magnetic resonance-ultrasound (MR-MR-US) fusion imaging navigation (FIN) with needle tail intelligent positioning (NTIP) to guide puncture in percutaneous transforaminal endoscopic discectomy (PTED). First, in a pig experiment, we found that puncture errors in lumbar intervertebral foramen (LIF) puncture using magnetic resonance-magnetic resonance-ultrasound (MR-MR-US) FIN with NTIP for experienced and novice operators were 2.00 ± 1.00 and 2.57 ± 0.98 mm, respectively (p=0.231), suggesting this technique was minimally dependent on experience. Then, two experienced surgeons agreed (inter-observer agreement к=0.801) that the quality of MR-MR fusion images was good or sufficient. Finally, we performed PTED in eight patients using MR-MR-US FIN with NTIP, and no significant complications were reported during LIF puncture. Overall, MR-MR-US FIN with NTIP may be a potential application for guiding puncture in PTED, but more clinical studies with a larger sample size are required to further evaluate the advantages of MR-MR-US FIN with NTIP.

Immediate alteration of the lumbar intervertebral foramen during the so-called osteopathic locking technique: A preliminary analysis on healthy subjects

BackgroundDegenerative processes in the lumbar spine can lead to a decrease of the disc height and an alteration of the foramen with potential compression of the nerve root. Several osteopathic manipulative techniques are designed to improve the intervertebral joints and the foraminal area. ObjectiveThis study was intended to explore the effect of so-called osteopathic manipulative locking technique (OMLT) on the lumbar foramen. MethodsTen asymptomatic volunteers underwent CT scan examination in neutral position and during OMLT targeting the L4-L5 level on the left side. Two subjects were excluded from the sample due to lumbosacral transitional anomaly. Anatomical modeling was obtained by segmenting imaging CT data. 3D kinematics and intervertebral foramen dimensions (height, width and area) were computed for both positioning. ResultsThe findings indicate that OLMT applied on the L4-L5 level consisted in small combined angular motions including extension, contralateral Lateral Bending and contralateral Axial Rotation. These motion components result in a significant alteration of the foramen height on the targeted side. In contrast, other foramen variables remained unchanged on both sides. ConclusionBetter understanding of how osteopathic manipulative technique may affect the intervertebral motion and the foraminal area could improve the knowledge in osteopathic approaches. Further investigations are needed to confirm these primary outcomes and to determine the potential clinical effects of such an application.

Cervical Spondylopathy and Lumbar Intervertebral Disc Herniation Coexist in Free Radical Metabolism and Focus Separation in the Body.

Lumbar disc herniation is a common lumbar disease in clinics, which is related to improper use of lumbar vertebrae and osteoporosis. Surgical removal of nucleus pulposus and maintenance of lumbar structural stability are important for the treatment of lumbar disc herniation. At present, in clinical percutaneous intervertebral foramen endoscopic surgery for lumbar disc herniation, interlaminar and intervertebral foramen approaches can be selected. Different approaches have different degrees of difficulty in the treatment of lumbar disc herniation, and the clinical effects that may be obtained are different. In this study, we observed the influencing factors of plasma nitric oxide (NO) and free radical metabolism in patients with lumbar disc herniation and the correlation between the effects of focus separation. The organic combination of local and total illness differentiation and dialectics, conventional acupuncture, and electrical stimulation was highlighted in this study, which linked local acupoints squeezed by nerve roots with distant acupoints along meridians. The use of authoritative quantitative standards and a multifactor assessment of the disease can accurately represent the disease's severity. The patient's condition changes in each period may be expressed more accurately, thoroughly, and objectively through the rise or reduction of the score, making self-evaluation easier for the patient. Electroacupuncture at point may be one of the most important strategies to minimize free radical damage, based on changes in plasma levels.

Spine system changes in soldiers after load carriage training in a plateau environment: a prediction model research

BackgroundLow back pain is the most common spinal disorder among soldiers, and load carriage training (LCT) is considered the main cause. We aimed to investigate changes in the spine system of soldiers after LCT at high altitudes and the change trend of the lumbar spine and surrounding soft tissues under different load conditions.MethodsMagnetic resonance imaging scans of the lumbar spines of nine soldiers from plateau troops were collected and processed. We used ImageJ and Surgimap software to analyze changes in the lumbar paraspinal muscles, intervertebral discs (IVDs), intervertebral foramina, and curvature. Furthermore, the multiple linear regression equation for spine injury owing to LCT at high altitudes was established as the mathematical prediction model using SPSS Statistics version 23.0 software.ResultsIn the paraspinal muscles, the cross-sectional area (CSA) increased significantly from 9126.4 ± 691.6 mm2 to 9862.7 ± 456.4 mm2, and the functional CSA (FCSA) increased significantly from 8089.6 ± 707.7 mm2 to 8747.9 ± 426.2 mm2 after LCT (P < 0.05); however, the FCSA/CSA was not significantly different. Regarding IVD, the total lumbar spine showed a decreasing trend after LCT with a significant difference (P < 0.05). Regarding the lumbar intervertebral foramen, the percentage of the effective intervertebral foraminal area of L3/4 significantly decreased from 91.6 ± 2.0 to 88.1% ± 2.9% (P < 0.05). For curvature, the lumbosacral angle after LCT (32.4° ± 6.8°) was significantly higher (P < 0.05) than that before LCT (26.6° ± 5.3°), while the lumbar lordosis angle increased significantly from 24.0° ± 7.1° to 30.6° ± 7.4° (P < 0.05). The linear regression equation of the change rate, △FCSA% = − 0.718 + 23.085 × load weight, was successfully established as a prediction model of spinal injury after LCT at high altitudes.ConclusionThe spinal system encountered increased muscle volume, muscle congestion, tissue edema, IVD compression, decreased effective intervertebral foramen area, and increased lumbar curvature after LCT, which revealed important pathophysiological mechanisms of lumbar spinal disorders in soldiers following short-term and high-load weight training. The injury prediction model of the spinal system confirmed that a load weight < 60% of soldiers’ weight cannot cause acute pathological injury after short-term LCT, providing a reference supporting the formulation of the load weight standard for LCT.

The Mechanism and Therapeutic Effect of Lumbar Intervertebral Disc Foramen Puncture on Neuropathic Pain Based on Digital Medical Technology

Lumbar disc herniation is a relatively common disease in orthopedics, most patients will experience varying degrees of waist pain after suffering from this disease, and severe cases may even be paralysed. In recent years, with the rapid progress of science and technology, minimally invasive surgery technology is also developing rapidly, and its advantages are also very prominent. Puncture technology, as one of the most important and difficult points, has a high requirement for doctors, so it is particularly important to master this technology thoroughly. In order to apply this technique more in clinical practice, improve its accuracy and success rate, and increase the efficiency of operation, 40 patients with lumbar intervertebral disc herniation were selected and randomly divided into experimental group (20 cases) and control group (20 cases). According to the principle of lumbar intervertebral space puncture, its length and angle were adjusted with high precision. Percutaneous lumbar intervertebral foramen puncture locator was used for treatment in the experimental group and the control group was treated with routine nursing intervertebral foramen puncture. The number of punctures, the time needed for successful puncture, the number of successful projections, puncture complications, and clinical efficacy of the two puncture methods were analyzed. The results showed that in the analysis of clinical puncture indicators, the number of punctures, the time needed for puncture, and fluoroscopy times in the experimental group were significantly different from those in the control group (P &lt; 0.01). The puncture method was determined through the design of the surgical approach to alleviate the symptoms as much as possible after operation. In the visual analogue score, follow-up showed that the visual analogue score of the experimental group was significantly lower than that of the previous one month and the last follow-up, with statistical significance (P &lt; 0.01), and the excellent and good rate was significantly increased by using lumbar intervertebral disc puncture, which was 94.7%. Therefore, through this study, it is found that the new type of lumbar intervertebral perforation positioning designed in this study can significantly improve the accuracy of puncture, the success rate increased significantly, and the experiment achieved the desired results. Although there are some shortcomings in the experiment, it still provides experimental basis for the clinical application of lumbar intervertebral disc puncture in the later stage.

Dimensional Changes of Lumbar Intervertebral Foramen in Direct Anterior Approach-Specific Hyperextension Supine Position.

ObjectiveTo investigate the changes in the lumbar intervertebral foramen (LIVF) dimensions from neutral supine to direct anterior approach (DAA)‐specific hyperextension supine position through a standardized three‐dimensional (3D) reconstruction computerized tomography (CT) method.MethodsA total of 35 healthy volunteers (18 men and 17 women) were included in this retrospective study. The mean age of enrolled subjects was 28.9 ± 5.0 years. In September 2018, all the individuals underwent a 3D CT scan of the lumbar spine in neutral and 30° hyperextension supine positions, which mimicked the patient’s position in DAA total hip arthroplasty (THA). The dimensions of the LIVF, including foraminal area, height, and width, were measured on 3D reconstructed CT models at all lumbar foraminal levels. Foraminal area was defined as the area bounded by the adjacent superior and inferior vertebral pedicles, the posterosuperior boundary of the inferior vertebral body, the surface of the intervertebral disc posteriorly, the posteroinferior boundary of the superior vertebral body, and the surface of the ligamentum flavum anteriorly. Foraminal height was defined as the longest distance between the border of the superior and the inferior pedicle. Foraminal width was defined as the shortest distance between the posteroinferior edge of the superior vertebrae and the opposing boundary. Subgroup analysis and multiple linear regression were used to evaluate the relationship between percentage changes of the LIVF dimensions and side, sex, and age.ResultsThe LIVF dimensions varied significantly between the two positions at all levels (P < 0.05). From neutral to hyperextension supine position, the foraminal area reduced by 20.1% at lumbar 1–2 (L1–2), 22.6% at L2–3, 19.9% at L3–4, 18.1% at L4–5, and 12.0% at lumbar 5–sacral 1 (L5–S1) level, respectively; the foraminal height reduced by 9.5% at L1–2, 10.5% at L2–3, 9.5% at L3–4, 9.6% at L4–5, and 6.1% at L5–S1 level, respectively; the foraminal width reduced by 12.8% at L1–2, 14.5% at L2–3, 13.0% at L3–4, 10.4% at L4–5, and 8.4% at L5–S1 level, respectively. The changes in LIVF dimensions were biggest at L2–3 level and smallest at L5–S1 level. Subgroup analysis showed that there were no significant differences in the percentage changes of LIVF dimensions between the sexes and sides (P > 0.05). Multiple linear analysis showed that the percentage changes of LIVF dimensions were not related to side, sex, and age (P > 0.05).ConclusionThe dimensions of the LIVF showed significant decrease at all levels in the DAA‐specific hyperextension supine position compared with the neutral supine position, and the percentage changes of LIVF dimensions were not influenced by side, sex, and age.

Micro-anatomical structures of the lumbar intervertebral foramen for full-endoscopic spine surgery: review of the literatures.

Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive spinal surgical technique. PELD can be performed via 2 routes, transforaminal (TF) or interlaminar. The TF approach is a well-established modality in the treatment of patients with herniated lumbar discs. This technique makes the most of the space within the intervertebral foramen where, as Kambin claimed, the safe approach to the lesion is possible. Knowledge of the lumbar artery with its branches and various ligaments of anatomies of the intervertebral foramen are needed to perform successful surgeries and to reduce complications.

X-ray measurement and analysis on parameters of intervertebral foramen in the lower lumbar spine associated with the superior articular process

Objectives: In this study, we aimed to supplement the database of intervertebral foramen by measuring the parameters of the lower lumbar spine related to the articular process of the X-ray, which could lay a theoretical foundation for the individualized surgery of transforaminal endoscopic spine technique (TEST). Methods: Anteroposterior and lateral X-rays of the lumbar spine from 104 adults (50 male and 54 female) who met the measurement criteria were selected. The height and width of the intervertebral foramen, the height of the intervertebral space, the length from the superior articular process (SAP) to the lower edge of the upper lumbar pedicle, and the length from SAP to posterior margin of superior vertebra posterior edge were measured. Results: There was no significant difference in the shape of the lower lumbar intervertebral foramen between normal adult men and women. There were significant differences in parameters related to the lower lumbar intervertebral foramen between the age group from 40 to 60 and above 60, and especially those related to the SAP. Conclusion: Parameters of the lower lumbar intervertebral foramen were obtained from 104 normal adults, which supplemented the lumbar intervertebral foramen database. After the age of 60, the morphology of the lower lumbar intervertebral foramen was significantly changed in normal adults, and especially parameters related to the SAP. This study provided a reference for individualized minimally invasive surgery using TEST for elderly people over 60 years of age. Keywords : Transforaminal endoscopic spine technique; Superior articular process; Intervertebral foramen; Lower lumbar spine; X-ray; Age

Relationship of the Exiting Nerve Root and Superior Articular Process in Kambin's Triangle: Assessment of Lumbar Anatomy Using Cadavers and Computed Tomography Imaging

Percutaneous transforaminal endoscopic diskectomy has been a major treatment for lumbar disk herniation. However, damage to exiting nerve roots is one of the most severe complications in this surgery. In this paper, the relationship of the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen was assessed using cadavers and computed tomography (CT) imaging. The anatomic relationship between the exiting nerve root and the superior articular process in Kambin's triangle of the intervertebral foramen was investigated on 6 cadavers. The distance between the exiting nerve and the superior articular process of the L1-2 to L5-S1 intervertebral foramina was measured using multiplane reconstruction. The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle was quite narrow both in cadaver and CT imaging study. The distance of the L5-S1 intervertebral foramen was the greatest, which was no more than 5.77 ± 0.56 mm. The distances increased gradually from the tip to the root, and the distances between the root and the tip were 0.91 ± 0.31 to 1.86 ± 0.57 mm, which took on a trapezoid shape that was relatively narrow at the proximal end and wider at the distal end. The bone-nerve space between the exiting nerve root and the superior articular process in Kambin's triangle of the lumbar intervertebral foramen wasexceedingly narrow. It is necessary to perform a foraminoplasty to enlarge the working space and decrease the possibility of injury to the exiting nerve root.

Morphometric measurement of lower lumbar intervertebral foramina based on digital three-dimensional simulation.

This study aimed to investigate the morphology of the lower lumbar intervertebral foramina through use of a digital three-dimensional (3D) simulation model to guide the endoscope through the intervertebral foramina. Individuals without disease affecting the lumbar vertebrae underwent computed tomography (CT) scanning in the supine position. The CT images obtained were imported to medical software to reconstruct a 3D model of the lumbar vertebrae. The stereoscopic longitudinal and transverse diameters of the lumbar intervertebral foramina were measured directly on the established simulation model. Comparisons in terms of sex and age were performed using t-test or analysis of variance. In total, 100 individuals were included in the study. Average longitudinal and transverse diameters of the lower lumbar intervertebral foramen decreased moving inferiorly. The longitudinal and transverse diameters of the lower lumbar intervertebral foramina were similar between sexes and between age groups. However, longitudinal diameter decreased with age (P 0.05). The reconstructed lumbar vertebrae simulation model presented in this study has high fidelity to the structure of the human lumbar spine. This approach provides individualized, accurate, standardized, and detailed guidance for endoscopic surgery through the lumbar intervertebral foramen.

Magnetic resonance imaging anatomy and morphometry of lumbar intervertebral foramina to guide safe transforaminal subarachnoid punctures.

Percutaneous transforaminal lumbar punctures (TFLPs) offer alternative access routes to the lumbar subarachnoid cistern. Safe fluoroscopic insertion of a needle through a lumbar intervertebral foramen (IVF) should ideally avoid the exiting spinal nerve and surrounding vascular pedicles. A crescentic region in the posterior aspect of IVF is the conventional position for needle placement during TFLP, but the underlying anatomic basis for this has not been evaluated fully. To enhance TFLP safety, we defined the morphometry of normal lumbar IVFs and precise locations of neurovascular structures in the IVF posterior crescent. We retrospectively reviewed high-resolution T2-weighted lumbar spine magnetic resonance images of 40 normal adults to establish normative dimensions of each IVF from L1 to L5 bilaterally. We segmented the IVF posterior crescent into three parts, and within each, measured the areas occupied by neurovascular structures. We statistically correlated the presence or absence of neurovascular structures in each crescent segment using a chi-square test. The mean morphometrics for all 304 IVFs in 10 males and 30 females of similar ages were: area 115.3 ± 29.5 mm2 ; height 18.0 ± 2.4 mm; and width at mid-disc level 5.6 ± 2.1 mm. We found a significant association between crescent segment and presence or absence of neurovascular structures (χ2 = 95.9, p < .001). A post-hoc calculation of adjusted standardized residuals identified a significant association between the middle crescent segment and absence of neurovascular structures. Thus, the middle segment of the IVF posterior crescent is significantly most devoid of neurovascular structures, and more often would be the safest target for needle placement during TFLP.

Three-Dimensional Morphological Characteristics of Lower Lumbar Intervertebral Foramen with Age.

Intervertebral foramen is the doorway of nerve root and it plays an important role of radiculopathy and surgical treatment of intervertebral foramen diseases. The purpose of the study is to obtain three-dimensional (3D) morphological characteristics of lumbar intervertebral foramen and their relationship with age. Pedicle-superior articular process (P-SAP), disc height between adjacent vertebra (DH), pedicle-inferior vertebrae (P-IV), inferior posterior vertebrae-superior articular process (IPV-SAP), and bony boundary area (BBA) were measured in entrance, middle slice, and exit of lumbar intervertebral foramen for 25 males of different age groups. Spinous process to intervertebral foramen entrance (SP-IFE) was measured for 25 males of different age groups. Overall, P-SAP and P-IV decreased and IPV-SAP increased from the entrance to the exit of intervertebral foramen for L3/4-L5S1. DH decreased at entrance slice, middle slice, and exit slice for L3/4-L5S1 with age. Significant difference with aging was found only at the middle slice of L3/4 and L4/5 for P-SAP. And the significant decrease of IPV-SAP was observed at middle slice of L3/4, entrance slice of L4/5 and L5S1, and exit slice of L5S1. SP-IFE is not consistent for all subjects. In addition, the decrease of BBA at L3/4 and L4/5 was observed earlier than at L5S1. The present study described detailed information of intervertebral foramen, which may be of benefit for better understanding of the pathology and surgical planning for intervertebral foramen diseases.

Evaluation of foraminal cross-sectional area in lumbar spondylolisthesis using kinematic MRI.

To evaluate the kinematic change of cross-sectional area of lumbar intervertebral foramen in degenerative lumbar spondylolisthesis patients using multi-positional MRI. Multi-positional MRI was performed on 31 patients diagnosed with single or multilevel degenerative lumbar spondylolisthesis and 31 control patients without degenerative lumbar spondylolisthesis. Foraminal area (FA) was measured at the lumbar spondylolisthesis level in degenerative lumbar spondylolisthesis group and at L3-4, L4-5, and L5-S1 level in the control group. FA was measured bilaterally in neutral, flexion, and extension positions. The difference in FA between the groups was analyzed using Mann-Whitney U test, and the difference between positions within groups was analyzed using Wilcoxon signed-rank test. Degenerative lumbar spondylolisthesis group showed significantly smaller FA on both sides and on average in all three positions compared to the control group (p < 0.05 all). From neutral to flexion position, the change in FA was significantly smaller in the degenerative lumbar spondylolisthesis group than in the control group on both sides and on average (p < 0.005 all). In degenerative lumbar spondylolisthesis group, the FA showed no significant change from neutral to flexion, but showed significant change from neutral to extension (p < 0.005 all). FA in the degenerative lumbar spondylolisthesis group was smaller than in the control group. There was no difference in FA in degenerative lumbar spondylolisthesis group from neutral to flexion, only from neutral to extension. Patients with degenerative lumbar spondylolisthesis have a higher chance of developing foraminal stenosis.

Spinal Nerve Position and Morphometric Analysis with Silicon Molds in the Cadaveric Lumbar Intervertebral Foramen

Spinal Nerve Position and Morphometric Analysis with Silicon Molds in the Cadaveric Lumbar Intervertebral Foramen

Morphometric Changes of the Lumbar Intervertebral Foramen after Percutaneous Endoscopic Foraminoplasty under Local Anesthesia.

Percutaneous endoscopic diskectomy (PED) for the lumbar spine is a relatively new technique that is becoming more common due to its relatively less invasive nature. However, one possible serious complication is an exiting nerve injury when the cannula of the endoscope is inserted into the neural canal through the intervertebral foramen. A technique to enlarge the intervertebral foramen, called foraminoplasty, was recently established to insert the cannula safely into an appropriate position in the neural canal. In this study we performed foraminoplasty during PED under local anesthesia on 15 patients. Using computed tomography scans before and after surgery, the morphometric changes of the intervertebral foramen were evaluated. Surgery-related complications were reviewed. There were 13 men and 2 women, 21 to 86 years of age (mean: 47.1 years). Disk levels were 13 cases at L4-L5, one case at L3-L4, and one case at L5-S1. In 50% of the cases, the mean foraminal area significantly increased from 58.6 mm2 before surgery to 88.4 mm2 after surgery (p < 0.05 by paired t test). The diameter of the foramen was increased at all three points: the lower end plate of the superior vertebrae, the disk, and the upper end plate of the inferior vertebrae. The area increased ∼ 1.5 times, especially at the upper end plate of the inferior vertebrae. In all cases, no exiting nerve injury was encountered during PED. Foraminoplasty was an effective method for avoiding exiting nerve root injury during transforaminal PED.