Sagittal whole-spine magnetic resonance imaging in 750 consecutive outpatients: accurate determination of the number of lumbar vertebral bodies

Anterior spinal fusion (ALIF/OLIF/LLIF) with lumbosacral transitional vertebra: A systematic review and proposed treatment algorithm

•Key anterior approaches differences in LSTV include vascular (aortic bifurcation/iliocaval confluence), muscular (psoas) and osseus anatomy (inter-crestal tangent/pubic symphysis), when compared to non-LSTV.•There are increased surgical deviations but not significantly greater complications for anterior approaches in LSTV.•Vascular awareness while accessing L45 will be in the presence of a more cephalad ABF and ICC with sacralized L5, and access to the deeper L56 level will be in the presence of a more caudal ABF and ICC in lumbarized S1.

Diagnostic treatment-level discrepancies in patients with lumbosacral radicular pain and lumbar spine anomalies

BACKGROUND

Lumbosacral transitional vertebra can result in an anomalous number of lumbar vertebrae associated with wrong level treatment. The primary aim of this study was to characterize discrepancies between reported referring levels and levels from MRI reports with treated levels. The secondary aim was to analyze interobserver variability between a pain physician and a radiologist when determining levels and classifying lumbosacral transitional vertebrae.

METHODS

Between February 2016 and October 2019, a retrospective case series of prospectively collected data of the affected levels mentioned in referrals, MRI reports and treated levels was performed. The counting process, level determination, classification of lumbosacral transitional vertebrae and a secondary control were carried out by independent researchers using a standard methodology.

RESULTS

Of the 2443 referrals, 143 patients had an anomalous number of lumbar vertebrae; of these, 114 were included for analysis. The vertebral level noted in the patient's file, in the referral, and the reported level of treatment differed in 40% of these cases. The vertebral level between the MRI reports and treatment differed in 46% of cases. The interobserver reliability (radiologist vs pain physician) for classifying a transitional vertebra was fair ((κ=0.40) and was substantial (κ=0.70) when counting the vertebrae.

CONCLUSION

In the presence of lumbar spine anomalies, we report a high prevalence of discrepancies between referral levels and MRI pathological findings with treatment levels. Further research is needed to better understand clinical implications.

Association between lumbosacral transitional vertebrae and spinal pathologies based on T2 whole-spine sagittal magnetic resonance imaging

PURPOSE

To assess the association between 4, 5, or 6 lumbar spine vertebrae and the presence of lumbar spinal pathologies.

METHODS

We reviewed all MRI reports and images performed between August 1st, 2018 and July 31st, 2019. Lumbar spine pathologies such as disc herniation, lytic spondylolisthesis, and spinal stenosis were recorded. The reviewer studied the T2 sagittal screening of the entire spine and counted down manually from C2 to T12 on the assumption that there are seven cervical and twelve dorsal vertebrae. We then recorded whether there were four, five, or six lumbar vertebrae.

RESULTS

Our work incorporated a total of 1985 patients for whom T2-weighted entire spine sagittal MR images were obtainable. The study cohort's average age was 52.2 ± 15.9 years, comprising 944 males and 1041 females. One hundred and thirty-three patients (6.7%) had 4 lumbar-type vertebrae; 1799 (90.6%) had 5 lumbar-type vertebrae; and 53 (2.7%) had 6 lumbar-type vertebrae. There was a statistically significant difference between the rates of 6 lumbar-type vertebrae in males versus females (p < 0.05). There was a statistically significant difference with more spinal stenosis patients in the 6 lumbar-type vertebrae compared to the 4 or 5 lumbar-type vertebrae groups (p < 0.001).

CONCLUSION

Our study shows that spinal stenosis is significantly more common in patients with 6 lumbar-type vertebrae.

Transitional vertebrae and numerical variants of the spine : prevalence and relationship to low back pain or degenerative spondylolisthesis

AIMS

Although lumbosacral transitional vertebrae (LSTV) are well-documented, few large-scale studies have investigated thoracolumbar transitional vertebrae (TLTV) and spinal numerical variants. This study sought to establish the prevalence of numerical variants and to evaluate their relationship with clinical problems.

METHODS

A total of 1,179 patients who had undergone thoracic, abdominal, and pelvic CT scanning were divided into groups according to the number of thoracic and lumbar vertebrae, and the presence or absence of TLTV or LSTV. The prevalence of spinal anomalies was noted. The relationship of spinal anomalies to clinical symptoms (low back pain, Japanese Orthopaedic Association score, Roland-Morris Disability Questionnaire) and degenerative spondylolisthesis (DS) was also investigated.

RESULTS

Normal vertebral morphology (12 thoracic and five lumbar vertebrae without TLTV and LSTV) was present in 531 male (76.7%) and 369 female patients (75.8%). Thoracolumbar transitional vertebrae were present in 15.8% of males and 16.0% of females. LSTV were present in 7.1% of males and 9.0% of females. The prevalence of the anomaly of 16 presacral mobile vertebrae (total number of thoracolumbar vertebrae and TLTV) without LSTV was 1.0% in males and 4.1% in females, and that of the anomaly of 18 vertebrae without LSTV was 5.3% in males and 1.2% in females. The prevalence of DS was significantly higher in females with a total of 16 vertebrae than in those with normal morphology. There was no significant correlation between a spinal anomaly and clinical symptoms.

CONCLUSION

Overall, 24% of subjects had anomalies in the thoracolumbar region: the type of anomaly differed between males and females, which could have significant implications for spinal surgery. A decreased number of vertebrae was associated with DS: numerical variants may potentially be a clinical problem. Cite this article: Bone Joint J 2021;103-B(7):1301-1308.

Lumbar plain radiograph is not reliable to identify lumbosacral transitional vertebra types according to Castellvi classification principle

Background

The anteroposterior view of the lumbar plain radiograph (AP-LPR) was chosen as the original and first radiographic tool to determine and classify lumbosacral transitional vertebra with morphological abnormality (MA-LSTV) according to the Castellvi classification. However, recent studies found that AP-LPR might not be sufficient to detect or classify MA-LSTV correctly. The present study aims to verify the reliability of AP-LPR on detecting and classifying MA-LSTV types, taking coronal reconstructed CT images (CT-CRIs) as the gold criteria.

Methods

Patients with suspected MA-LSTVs determined by AP-LPR were initially enrolled. Among them, those who received CT-CRIs were formally enrolled to verify the sensitivity of AP-LPR on detecting and classifying MA-LSTV types according to the Castellvi classification principle.

Results

A total of 298 cases were initially enrolled as suspected MA-LSTV, among which 91 cases who received CT-CRIs were enrolled into the final study group. All suspected MA-LSTVs were verified to be real MA-LSTVs by CT-CRIs. However, 35.2% of the suspected MA-LSTV types judged by AP-LPR were not consistent with the final types judged by CT-CRIs. Two suspected type IIIa and 20 suspected type IIIb MA-LSTVs were verified to be true, while 9 of 39 suspected type IIa, 9 and 3 of 17 suspected type IIb, and 11 of 13 suspected type IV MA-LSTVs were verified to truly be type IIIa, IIIb, IV and IIIb MA-LSTVs by CT-CRIs, respectively. Incomplete joint-like structure (JLS) or bony union structure (BUS) and remnants of sclerotic band (RSB) between the transverse process (TP) and sacrum were considered to be the main reasons for misclassification.

Conclusion

Although AP-LPR could correctly detect MA-LSTV, it could not give accurate type classification. CT-CRIs could provide detailed information between the TP and sacrum area and could be taken as the gold standard to detect and classify MA-LSTV.

Re-examining the Spectrum of Lumbosacral Transitional Dysmorphisms: Quantifying Joint Asymmetries and Evaluating the Anatomy of Screw Fixation Corridors

Objective

Although a wide range of sacral dysmorphisms has been documented with lumbosacral transitional vertebrae (LSTV) variations, quantitative characterization of the upper segment morphology and articular anatomy across the array of lumbosacral transitions are hardly found in the literature. This study presents LSTV anomalies as a series of sequential morphological changes (the LSTV spectrum) and quantitatively compares 6 LSTV subtypes with normative sacral dimensions including the anatomy at the upper sacral segments used for percutaneous sacroiliac screw insertion.

Methods

Seven linear dimensions were measured from LSTV subtypes and normal sacral variants from dried adult sacral specimens. The auricular, superior articular and facet surface areas were quantified. Obliquity and thickness of osseous corridors used for sacroiliac screw fixation were measured. Data were statistically compared within and between LSTV subtypes and the normal variants.

Results

LSTVs presented a wide range of morphometric differences in comparison to the normal bones. Grouping LSTV according to auricular surface positions (high, normal, and low) demonstrated significant between-group differences in the obliquity and thickness at the S1 and S2 segmental corridors.

Conclusion

Frequent occurrence of LSTV in the general population may require evaluation of anatomical parameters in these variations for safe sacroiliac instrumentation around this region.

Psoas proximal insertion as a simple and reliable landmark for numbering lumbar vertebrae on MRI of the lumbar spine

OBJECTIVE

To evaluate the value of psoas muscle proximal insertion for correct numbering of the lumbar vertebrae in MRI, in particular in case of lumbosacral transitional vertebra (LSTV).

METHODS

Two radiologists assessed 477 MRI scans of the lumbar spine with a sagittal localizer sequence on the whole spine for numbering vertebrae caudally from C2. Proximal insertion of the psoas was determined as the most proximal vertebra with psoas over half of its body on coronal T2 STIR sequence. The last lumbar vertebra was named considering both its number and the presence or absence of LSTV according to Castellvi classification. These same parameters were also assessed on 207 PET-CT scans of another cohort including the whole spine.

RESULTS

Proximal insertion of the psoas was L1 in 94.1% of cases: 98.5% in case of modal anatomy, 81.4% in case of LSTV, and 51.7% in case of missing or supernumerary lumbar vertebra without LSTV. There was no statistically significant difference between MRI and CT data. The inter-reader agreement for determination of psoas proximal insertion was excellent (kappa = 0.96).

CONCLUSION

Proximal insertion of the psoas muscle is a helpful marker for correct numbering of the lumbar vertebrae in MRI and to detect a complete lumbosacral segmentation anomaly.

KEY POINTS

• Proximal insertion of the psoas muscle can be easily identified on a coronal T2 STIR sequence. • Psoas proximal insertion on the spine almost always designates the first lumbar vertebra and is helpful to accurately number all lumbar vertebrae, especially in case of lumbosacral transitional vertebra. • Conversely, when psoas muscle does not insert five lumbar bodies above the apparent lumbosacral joint, the probability of variation in the number of lumbar vertebrae is high.

Spinal Enumeration by Morphologic Analysis of Spinal Variants: Comparison to Counting in a Cranial-To-Caudal Manner

Objective

To compare the spinal enumeration methods that establish the first lumbar vertebra in patients with spinal variants.

Materials and Methods

Of the 1446 consecutive patients who had undergone computed tomography of the spine from March 2012 to July 2016, 100 patients (62 men, 38 women; mean age, 47.9 years; age range, 19-88 years) with spinal variants were included. Two radiologists (readers 1 and 2) established the first lumbar vertebra through morphologic analysis of the thoracolumbar junction, and labeled the vertebra by counting in a cranial-to-caudal manner. Inter-observer agreement was established. Additionally, reader 1 detected the 20th vertebra under the assumption that there are 12 thoracic vertebra, and then classified it as a thoracic vertebra, lumbar vertebra, or thoracolumbar transitional vertebra (TLTV), on the basis of morphologic analysis.

Results

The first lumbar vertebra, as established by morphologic analysis, was labeled by each reader as the 21st segment in 65.0% of the patients, as the 20th segment in 31.0%, and as the 19th segment in 4.0%. Inter-observer agreement between the two readers in determining the first lumbar vertebra, based on morphologic analysis, was nearly perfect (κ value: 1.00). The 20th vertebra was morphologically classified as a TLTV in 60.0% of the patients, as the first lumbar segment in 31.0%, as the second lumbar segment in 4.0%, and as a thoracic segment in 5.0%.

Conclusion

The establishment of the first lumbar vertebra using morphologic characteristics of the thoracolumbar junction in patients with spinal variants was consistent with the morphologic traits of vertebral segmentation.

A review of lumbosacral transitional vertebrae and associated vertebral numeration

PURPOSE

To review the current literature on methods of accurate numeration of vertebral segments in patients with Lumbosacral transitional vertebrae (LSTVs). LSTVs are a common congenital anomaly of the L5-S1 junction. While their clinical significance has been debated, unquestionable is the need for their identification prior to spinal surgery. We hypothesize that there are no reliable landmarks by which we can accurately number transitional vertebrae, and thus a full spinal radiograph is required.

METHODS

A Pubmed and EMBASE search using various combinations of specific key words including "LSTV", "lumbosacral transitional vertebrae", "count", "vertebral numbering", and "number" was performed.

RESULTS

The gold standard for spinal segment numeration in patients with LSTV remains whole spine imaging and counting caudally, starting from C2. If whole spine imaging is not available, the use of the iliac crest tangent sign on coronal magnetic resonance imaging (MRI) has fairly reliable sensitivity and specificity (81 and 64-88%, respectively) for accurate numeration of LSTV. The role of paraspinal anatomic markers such as the right renal artery, superior mesenteric artery, aortic bifurcation, and conus medullaris, for identification of vertebral levels is unreliable and should not be used.

CONCLUSIONS

A sagittal whole spine view should be added as a scout view when patients obtain lumbar MRI to standardize the vertebral numbering technique. To date, there has been no other method for accurate numeration of a transitional vertebral segment, other than counting caudally from C2. These slides can be retrieved under Electronic Supplementary Material.

Incidence of numerical variants and transitional lumbosacral vertebrae on whole-spine MRI

Objectives

This study sets out to prospectively investigate the incidence of transitional vertebrae and numerical variants of the spine.

Materials and methods

Over a period of 28 months, MRIs of the whole spine were prospectively evaluated for the presence of transitional lumbosacral vertebrae and numerical variants of the spine.

Results

MRI of the whole spine was evaluated in 420 patients, comprising 211 female and 209 male subjects. Two patients had more complex anomalies. Lumbosacral transitional vertebrae were seen in 12 patients: eight sacralised L5 (3 male, 5 female) and four lumbarised S1 (3 male, 1 female). The incidence of transitional vertebrae was approximately 3.3. % (14/418). Thirty-two (7.7 %) of 418 patients had numerical variants of mobile vertebrae of the spine without transitional vertebrae. The number of mobile vertebrae was increased by one in 18 patients (12 male, 6 female), and the number was decreased by one in 14 patients (4 male, 10 female).

Conclusions

Numerical variants of the spine are common, and were found to be almost 2.5 times as frequent as transitional lumbosacral vertebrae in the study population. Only whole-spine imaging can identify numerical variants and the anatomical nature of transitional vertebrae. The tendency is toward an increased number of mobile vertebrae in men and a decreased number in women.

Main messages

• Numerical variants of the spine are more common than transitional vertebrae.

• Spinal numerical variants can be reliably identified only with whole-spine imaging.

• Increased numbers of vertebrae are more common in men than women.

• Transitional lumbosacral vertebrae occurred in about 3.3 % of the study population.

• The incidence of numerical variants of the spine was about 7.7 %.

Thoracolumbar junction: morphologic characteristics, various variants and significance

OBJECTIVE:

This study aimed to assess the types of vertebral segments at the thoracolumbar junction, as they relate to the most caudal ribs, to evaluate the reliability of this assessment using axial CT with curved planar reformatting (CPR) images, to describe the morphologic characteristics of a thoracolumbar transitional vertebra (TLTV), to introduce a new classification system for the TLTV and to evaluate the reliability of the classification system using axial CT with CPR images.

METHODS:

This was a retrospective review of 744 consecutive patients who underwent spine CT imaging that included the thoracolumbar junction. Two radiologists (Readers 1 and 2) independently evaluated the axial CT with CPR images for all cases (n = 744). Each radiologist differentiated the vertebral segments at the thoracolumbar junction as TLTV or non-TLTV (thoracic segment or lumbar segment). In addition, each radiologist classified the 94 patients with the TLTV using a novel classification system. Interobserver agreement between the two radiologists regarding the differentiation of vertebral segments at the thoracolumbar junction was analysed with kappa statistics. Similarly, intra- and interobserver agreement regarding TLTV classification was analysed with kappa statistics.

RESULTS:

Interobserver agreement between the two readers with respect to the differentiation of vertebral segments at the thoracolumbar junction via axial CT with CPR images was nearly perfect (κ-value: 0.959). Interobserver agreement between the two readers with respect to TLTV classification using axial CT with CPR images was nearly perfect (κ-value: 0.846). In addition, intraobserver agreement for Reader 1 was also nearly perfect (κ-value: 0.877).

CONCLUSION:

Morphologic analysis of the thoracolumbar junction may help accurate spinal enumeration.

ADVANCES IN KNOWLEDGE:

Consideration of various variants at the thoracolumbar junction should help radiologists and clinicians to interpret the morphology of the thoracolumbar junction. This may facilitate communication with the referring clinician, thereby reducing the error in spinal enumeration.

Merits of different anatomical landmarks for correct numbering of the lumbar vertebrae in lumbosacral transitional anomalies

PURPOSE

Anatomical landmarks and their relation to the lumbar vertebrae are well described in subjects with normal spine anatomy, but not for subjects with lumbosacral transitional vertebra (LSTV), in whom correct numbering of the vertebrae is challenging and can lead to wrong-level treatment. The aim of this study was to quantify the value of different anatomical landmarks for correct identification of the lumbar vertebra level in subjects with LSTV.

METHODS

After IRB approval, 71 subjects (57 ± 17 years) with and 62 without LSTV (57 ± 17 years), all with imaging studies that allowed correct numbering of the lumbar vertebrae by counting down from C2 (n = 118) or T1 (n = 15) were included. Commonly used anatomical landmarks (ribs, aortic bifurcation (AB), right renal artery (RRA) and iliac crest height) were documented to determine the ability to correctly number the lumbar vertebrae. Further, a tangent to the top of the iliac crests was drawn on coronal MRI images by two blinded, independent readers and named the 'iliac crest tangent sign'. The sensitivity, specificity and the interreader agreement were calculated.

RESULTS

While the level of the AB and the RRA were found to be unreliable in correct numbering of the lumbar vertebrae in LSTV subjects, the iliac crest tangent sign had a sensitivity and specificity of 81 % and 64-88 %, respectively, with an interreader agreement of k = 0.75.

CONCLUSION

While anatomical landmarks are not always reliable, the 'iliac crest tangent sign' can be used without advanced knowledge in MRI to most accurately number the vertebrae in subjects with LSTV, if only a lumbar spine MRI is available.

Is the iliolumbar ligament a reliable identifier of the L5 vertebra in lumbosacral transitional anomalies?

OBJECTIVE

Sufficiently sized studies to determine the value of the iliolumbar ligament (ILL) as an identifier of the L5 vertebra in cases of a lumbosacral transitional vertebra (LSTV) are lacking.

METHODS

Seventy-one of 770 patients with LSTV (case group) and 62 of 611 subjects without LSTV with confirmed L5 level were included. Two independent radiologists using coronal MR images documented the level(s) of origin of the ILL. The interobserver agreement was analysed using weighted kappa/kappa (wκ/κ) and a Fischer's exact test to assess the value of the ILL as an identifier of the L5 vertebra.

RESULTS

The ILL identified the L5 vertebra by originating solely from L5 in 95 % of the controls; additional origins were observed in 5 %. In the case group, the ILL was able to identify the L5 vertebra by originating solely from L5 in 25-38 %. Partial origin from L5, including origins from other vertebra was observed in 39-59 % and no origin from L5 at all in 15-23 % (wκ = 0.69). Both readers agreed that an ILL was always present and its origin always involved the last lumbar vertebra.

CONCLUSION

The level of the origin of the ILL is unreliable for identification of the L5 vertebra in the setting of an LSTV or segmentation anomalies.

KEY POINTS

• The origin of the ILL is evaluated in subjects with an LSTV. • The origin of the ILL is anatomically highly variable in LSTV. • The ILL is not a reliable landmark of the L5 vertebra in LSTV.

Is any landmark reliable in vertebral enumeration? A study of 3.0-Tesla lumbar MRI comparing skeletal, neural, and vascular markers

PURPOSE

This study aimed to determine the reliability of the iliolumbar ligament (ILL), 12th costa, aortic bifurcation (AB), right renal artery (RRA), and conus medullaris (CM) for numbering of vertebral segments.

SUBJECTS AND METHODS

Five hundred five patients underwent routine lumbar MRI examinations including a cervicothoracic sagittal scout and T1 and T2-weighted sagittal and axial turbo spin echo images. Images were evaluated by two radiologists separately.

RESULTS

The identifiability of ILL and 12th costa were 85.7% and 48.1%. AB, RRA, and CM were located more caudally in lumbarized S1 and more cranially in sacralized L5 cases.

CONCLUSION

Landmarks suggested by previous studies are not reliable alternatives to cervicothoracic scout images due to wide ranges of distribution and inconsistencies in identification.

Ten percent of patients with adolescent idiopathic scoliosis have variations in the number of thoracic or lumbar vertebrae

BACKGROUND

Surveys have demonstrated that wrong-site surgery of the spine is performed by up to 50% of spine surgeons over the course of a career. Inaccurate identification of appropriate vertebral levels is a common reason for wrong-site spine surgery. The present study examined the prevalence of variations in the number of vertebrae in patients with adolescent idiopathic scoliosis.

METHODS

A retrospective review of radiographs and reports of 364 consecutive patients undergoing operative treatment for adolescent idiopathic scoliosis at a single center was performed. The study included eighty-eight male patients (24%) and 276 female patients (76%) with a mean age of fourteen years (range, ten to twenty years). Radiographs were reviewed to assess the number of thoracic and lumbar vertebrae and the presence of a lumbosacral transitional vertebra.

RESULTS

Ten percent of the patients (thirty-eight) had an atypical number of vertebrae in the thoracic and/or lumbar spine. Twenty-one patients (5.8%) had an atypical number of thoracic vertebrae, with fourteen having eleven thoracic vertebrae and seven patients having thirteen. Twenty-four patients (6.6%) had an atypical number of lumbar vertebrae, with four having four lumbar vertebrae and twenty patients having six. A lumbosacral transitional vertebra was present in 6.3% (twenty-three) of the patients. Multilevel vertebral anomalies were present in 1.9% of the patients (seven of 364). A variation in the number of vertebrae had been identified in 0.5% (two) of the reports by the radiologist.

CONCLUSIONS

Variations in the number of thoracic or lumbar vertebrae were found in 10% of patients with adolescent idiopathic scoliosis but had been identified in only 0.5% of the radiology reports.

Redefining lumbosacral transitional vertebrae (LSTV) classification: integrating the full spectrum of morphological alterations in a biomechanical continuum

In light of advancements in imaging techniques and basic science studies, this study proposes modifications in the existing Castellvi's classification for better clinical and biomechanical correlation of LSTV subtypes. LSTVs are commonly occurring variations of the lower spine. The current system does not include functionally important structural variations of the neural arch components and sacral auricular surfaces induced by LSTV afflictions within the classification. This study is an attempt to integrate vital biomechanical correlates into the proposed modification. Emerging diagnostic and clinical evidence also point out the need of understating subdivisions within LSTV anomalies as distinctly stratified entities to get a better correlation with the biomechanical continuum involved with LSTV associated low back pain. Important neural arch element and sacral auricular surface alterations associated with each LSTV subtypes were studied from a large number of osseous samples and data available from published LSTV related clinical and morphological studies. Sacralisation and lumbarisation were designated separate stratifications in the proposed revision, with arrangement of the LSTV subtypes as members of a LSTV anatomical 'array' extending cranio-caudally at the lumbo-sacral junction. The proposed modification is capable of identifying LSTV associated structural defects (in anterior and posterior elements), their exact level of occurrence and status of facet and auricular surface morphologies. Coding for the inclusion of biomechanically important alterations associated with LSTV types within the proposed new classification would probably be helpful in better clinical correlation of LSTV.

Numbering of vertebrae on MRI using a PACS cross-referencing tool

BACKGROUND

For the detection and documentation of numeric variations on spine magnetic resonance imaging (MRI), different techniques have previously been introduced. However, these methods require additional special imaging algorithms, software, or devices. We intend to introduce a vertebral numbering method using the existing picture archiving and communication system (PACS) and MRI system.

PURPOSE

To assess the accuracy of a method for numbering presacral vertebrae based on the cross-referencing of two sagittal MRI series.

MATERIAL AND METHODS

This study was a retrospective review of 224 consecutive patients who underwent both lumbar MRI with cervicothoracic scan and whole spine radiographic examinations. A radiologist and a neurosurgeon independently counted the number of presacral vertebrae in a cranial-to-caudal approach with cross-referencing of cervicothoracic and lumbar MRI sagittal series on the PACS workstation. Radiographic numbering from the cervical through the thoracic to the lumbar vertebrae, as a reference standard, was completed independently by the two reviewers. An analysis of the inter-observer and intermodality agreements of radiography and MRI was done.

RESULTS

In all cases except one, concordant numbering existed between the two modalities of MRI cross-referencing and radiographs combination. Both observers agreed completely, with no inter-observer discordance.

CONCLUSION

The number of vertebrae could be identified consistently by counting caudally from C2 with cross-referencing cervicothoracic and lumbosacral sagittal MRI scans on the PACS workstation.

Spine segmentation and enumeration and normal variants

This article provides a comprehensive review of spine segmentation and enumeration. This important and relatively underappreciated issue, when neglected, frequently results in confusion in vertebral numbering and ultimately may result in wrong segment interventions. The authors supplement this topic with a discussion of normal variants.

Incidental vertebral lesions

Incidental vertebral lesions on imaging of the spine are commonly encountered in clinical practice. Contributing factors include the aging population, the increasing prevalence of back pain, and increased usage of MR imaging. Additionally, refinements in CT and MR imaging have increased the number of demonstrable lesions. The management of incidental findings varies among practitioners and commonly depends more on practice style than on data or guidelines. In this article we review incidental findings within the vertebral column and review management of these lesions, based on available Class III data.

Relationship of sacral articular surfaces and gender with occurrence of lumbosacral transitional vertebrae

BACKGROUND CONTEXT

Research on lumbosacral transitional vertebra (LSTV) has yielded important information on the structural alterations of the sacrum associated with LSTV. Nevertheless, very little data are available on the relationship of a given type of LSTV with either a typical pattern of sacral morphology or its gender distribution in the population.

PURPOSE

To investigate the probable relationship between different variants of LSTVs with sacral morphology at the articular surfaces of the bone and the gender distribution of the anomalies in the population.

STUDY DESIGN

Cross-sectional descriptive study involving dried human sacral bones and meta-analysis of data available related to LSTVs.

METHODS

Three hundred twenty sacra were screened for the presence of LSTV, the type of auricular surface, and facet joints in them. Samples were grouped against their sexes, type of the auricular surfaces present in them, the nature of facet joints, and the variety of LSTV (if present). Data on LSTV from reliable Internet databases were collected to account for the prevalence of LSTV in the population in terms of the types of the anomaly and their gender distribution.

RESULTS

The detection rates of LSTV in the present study were similar to those observed in available literature. Accessory L5-S1 articulations and lumbarization of S1 were more commonly observed in the women. Sacralization was seen to be predominantly distributed in men. Higher auricular surfaces were associated with accessory articulations; lower auricular surfaces were present with partially separated S1 segment and in L5-S1 specimens. Morphology of the facets significantly altered in LSTV with accessory articulations.

CONCLUSIONS

Different lumbosacral transitions share a stronger, definite, and specific patterns of relationship with certain sacral morphologies and gender. It is important to recognize the nuances of these connections so as to understand low back pain conditions in the setting of a typical sacral articular morphology or the sex of the individual.

Wrong-level surgery: A unique problem in spine surgery

Background:

Even though a lot of effort has gone into preventing operating at the wrong site and wrong patient, wrong-level surgery is a unique problem in spine surgery.

Methods:

The current method to prevent wrong level spine surgery performed is mainly relied on intra-operative X-ray. Unfortunately, because of the unique features and anatomy of the spinal column, wrong level spine surgery still happens. There are situations that even with intraoperative X-ray, correct level still cannot be reliably identified.

Results:

Examples of patient whose surgery can easily be performed on the wrong level are illustrated. A protocol to prevent wrong-level spine surgery preformed is developed.

Conclusion:

The consequence of wrong-level spine surgery not only generates another surgery of the intended level; it is usually also associated with lawsuit. Strictly following this protocol can prevent wrong-level spine surgery.