Lumbosacral transitional vertebrae: classification, imaging findings, and clinical relevance

Determination of lumbosacral transitional vertebrae in kidney urinary bladder x-ray films in the Saudi population

OBJECTIVES

To investigated the rate of occurrence of lumbosacral transitional vertebrae (LSTV), spinal variant, in kidney urinary bladder (KUB) plain radiographs in a Saudi population.  Methods: Between January 2012 to January 2015, KUB plain films obtained from patients at King Abdulaziz University Hospital, Jeddah, Saudi Arabia, were reviewed, and the presence or absence of LSTV was documented and classified as incomplete or complete. Patients who had evidence of spinal surgery that would obscure the view were excluded.  Results: A total of 2078 patients underwent KUB examinations during the study period; LSTV anomalies were detected in 158 of these. Sacralization was present in 153 (96.8%) of this cohort, while lumbarization was present in 5 (3.2%). A total of 136 (86.1%) of the sacralized segments were of the incomplete type, whereas 17 (10.7%) were complete. Of the lumbarized vertebrae, 3 (1.8%) were incomplete, and 2 (1.2%) were complete. The most frequent type in men was type Ib (28.5%) for sacralized segments, and type IIb for lumbarized segments (0.6%). In women, type Ia was the most common form of sacralized segments (11.3%) and type IIb was the most common form of lumbarized segments (2.8%). Conclusion: The prevalence of LSTV in Saudi patients is 7.6%, with a higher incidence of sacralization than lumbarization. Further studies with larger sample sizes and longer follow-up time are needed to demonstrate the clinical significance thereof.

Malformed vertebrae: a clinical and imaging review

A variety of structural developmental anomalies affect the vertebral column. Malformed vertebrae can arise secondary to errors of vertebral formation, fusion and/or segmentation and developmental variation. Malformations can be simple with little or no clinical consequence, or complex with serious structural and neurologic implications. These anomalies can occasionally mimic acute trauma (bipartite atlas versus Jefferson fracture, butterfly vertebra versus burst fracture), or predispose the affected individual to myelopathy. Accurate imaging interpretation of vertebral malformations requires knowledge of ageappropriate normal, variant and abnormal vertebral morphology and the clinical implications of each entity. This knowledge will improve diagnostic confidence in acute situations and confounding clinical scenarios.

This review article seeks to familiarize the reader with the embryology, normal and variant anatomy of the vertebral column and the imaging appearance and clinical impact of the spectrum of vertebral malformations arising as a consequence of disordered embryological development.

Teaching points

• Some vertebral malformations predispose the affected individual to trauma or myelopathy.

• On imaging, malformed vertebrae can be indistinguishable from acute trauma.

• Abnormalities in spinal cord development may be associated and must be searched for.

• Accurate interpretation requires knowledge of normal, variant and abnormal vertebral morphology.

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.

The morphological relationship between lumbosacral transitional vertebrae and lumbosacral pedicle asymmetry

Introduction

The clinical significance of lumbosacral transitional vertebrae (LSTV) has been reported. However, the association between LSTV and lumbosacral pedicle anatomical anomaly has not been investigated. We hypothesized that LSTV might be associated with lumbosacral anatomical anomaly. The purpose of this study was to examine the morphological association between LSTV and lumbosacral pedicle asymmetry (PA) using computed tomography (CT).

Methods

A retrospective review of CT images of 347 lumbosacral degenerative disease patients was performed. We divided the subjects into two groups: the normal and LSTV groups. LSTV was classified based on Castellvi's classification. PA was defined as a difference of more than 20° between the right and left angles of the pedicle.

Results

Seventy out of 347 lumbosacral degenerative disease patients (20.17%) were diagnosed with LSTV. In the normal group, only a 0.54% incidence of PA was seen; however, with respect to the LSTV group, a 9.29% incidence of PA was seen. A significant difference in PA incidence was observed between the groups (p < 0.001). Type IIIa and Type IV in the LSTV group showed a statistically significant PA incidence rate (p = 0.004 and p = 0.039, respectively).

Conclusions

Our study demonstrated that there was a significant difference in the incidence of PA between LSTV subjects and normal subjects. Moreover, the incidence of PA was significantly higher in LSTV subjects with severe anomaly. These results suggested that lumbosacral spine anomaly might have a close relationship with the incidence of PA and lumbosacral nerve root asymmetry. Therefore, morphological evaluation of the pedicle is important for preoperative surgical management, especially in cases using pedicle screws. This information could lower the incidence of pedicle screw malposition when pedicle screws are inserted at the lumbosacral spine.

Differentiation and classification of thoracolumbar transitional vertebrae

The literature states that transitional vertebrae at any junction are characterized by features retained from two adjacent regions in the vertebral column. Currently, there is no published literature available that describes the prevalence or morphology of thoracolumbar transitional vertebrae (TLTV). The aim of this study was to identify the qualitative characteristics of transitional vertebrae at the thoracolumbar junction and establish a technique to differentiate the various subtypes that may be found. A selection of vertebral columns from skeletal remains (n = 35) were evaluated in this study. Vertebrae were taken based on features that are atypical for vertebrae in each relative region. The transitional vertebrae were qualitatively identified based on overlapping thoracic and lumbar features of vertebrae at the thoracolumbar junction. The following general overlapping characteristics were observed: aplasia or hypoplasia of the transverse process, irregular orientation on the superior articular process and atypical mammillary bodies. The results show that the most frequent location of the transitional vertebrae was in the thoracic region (f = 23). The second most frequent location was in the lumbar region (f = 10). In two specimens of the selection (f = 2), an additional 13th thoracic vertebra was present which functioned as a transitional vertebra. This study concluded that one can accurately identify the characteristics of transitional vertebrae at the thoracolumbar junction. In addition, the various subtypes can be differentiated according to the region in the vertebral column the vertebra is located in and the relative number of vertebral segments in the adjacent regions of the vertebral column. This provides a qualitative tool for researchers to differentiate the transitional vertebrae from distinctly different typical thoracic or lumbar vertebrae at the thoracolumbar junction.

Clinical Outcomes After Posterior Lumbar Interbody Fusion: Comparison of Cortical Bone Trajectory and Conventional Pedicle Screw Insertion

STUDY DESIGN

This study is a retrospective cohort study using prospectively collected data.

OBJECTIVE

To compare the effectiveness of posterior lumbar interbody fusion (PLIF) using the cortical bone trajectory (CBT) and conventional pedicle screw (PS) techniques.

SUMMARY OF BACKGROUND DATA

There are few published studies to date comparing PLIF using CBT technique with PLIF using the conventional PS technique.

METHODS

We studied 119 consecutive patients who underwent single-level PLIF between 2010 and 2014 with a minimum 12-month follow-up. Forty-two patients underwent CBT-PLIF (the CBT group) and 77 underwent conventional PS-PLIF (the PS group). Clinical outcomes were assessed by the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and visual analog scale (VAS). To assess perioperative pain, a 6-point Numeric Rating Scale score and the total amount of diclofenac sodium suppositories used were recorded. The operative time and blood loss were recorded. Muscle damage was evaluated by serum creatine kinase concentrations. Fusion status was evaluated using 3-dimensional computed tomography 12 months postoperatively. We used inverse probability of treatment weighting based on the propensity score to reduce confounding factors.

RESULTS

There were no significant between-group differences in operative time or fusion rates, whereas the CBT group experienced significantly less blood loss, lower postoperative creatine kinase levels, less diclofenac sodium suppositories, and lower Numeric Rating Scale scores than the PS group did. The change in the JOABPEQ subdomain score for social life function 1 month postoperatively was the only significantly different factor among the JOABPEQ and VAS scores.

CONCLUSIONS

Both procedures were comparable in terms of clinical outcomes and fusion rates, but CBT-PLIF provided the additional benefits of less blood loss, less intraoperative muscle damage, less perioperative pain, and earlier recovery to normal activities.

Lumbosacral Transitional Segments: An Interventional Spine Specialist's Practical Approach

The presence of a lumbosacral transitional vertebrae (LSTV) should prompt a more detailed preprocedural evaluation of the vertebral column to accurately determine spinal levels. An LSTV should prompt the use of corroborating intraprocedural imaging to verify morphology. The most important factors in treating lumbosacral transitional segments are communication among treating physicians to ensure segmental enumeration consistency and associated appropriate patient treatment.

Proximate cause, anatomical correlates, and obstetrical implication of a supernumerary lumbar vertebra in humans

OBJECTIVES

Three issues are considered on variation in number of presacral vertebrae (PSV) in humans: (1) sexual difference in number of PSV, (2) inactivation of Hoxd-11 gene as etiology for a supernumerary lumbar vertebra, and (3) anatomical correlates of a supernumerary lumbar vertebra, including lumbar-sacral nearthrosis, and pelvic size.

MATERIALS AND METHODS

Sample was 407 skeletonized females and 1,318 males from United States; ages at death were 20 to 49 years. Two subsamples of males were used: (1) 98 with modal numbers of cervical, thoracic, lumbar, and sacral vertebrae (PSV = 24) and (2) 45 with a supernumerary lumbar vertebra but modal numbers for other vertebral segments (PSV = 25). Measurements were taken of ulna, second metacarpal, vertebrae, femur, and pelvis; presence of lumbar-sacral nearthrosis was observed.

RESULTS

Although 90% of females and males have 24 PSV, females have higher frequency of 23 PSV and males have higher frequency of 25 PSV. Compared to males with 24 PSV, males with 25 PSV and supernumerary lumbar vertebra show (1) no difference in anatomies associated with inactivation of Hoxd-11, and (2) higher frequency of lumbar-sacral nearthrosis and smaller pelvic inlet circumference.

DISCUSSION

Sexual difference in number of PSV may be due to tempo of somite formation and Hox gene activation. Hypothesis is not supported that a supernumerary lumbar vertebra is due to inactivation of Hoxd-11. The presence of a supernumerary lumbar vertebra is associated with small pelvic inlet circumference, which can be obstetrically disadvantageous.

An Unusual Case Report of Bertolotti's Syndrome: Extraforaminal Stenosis and L5 Unilateral Root Compression (Castellvi Type III an LSTV)

Introduction:

Castellvi Type III lumbosacral transitional vertebrae (LSTV) is an unusual case of Bertolotti’s syndrome (BS) due to extraforaminal stenosis, especially manifesting in elderly patients.

Case Report:

We report a case of BS in a 62 years old Greek female. The signs of the clinical examination are low back pain, sciatica, hypoesthesia, and pain to the contribution of L5 nerve. Imaging techniques revealed an LSTV Type III a (complete sacralization between LSTV and sacrum).

Conclusion:

Despite the fact that LSTV is a congenital lesion, the clinical manifestation of BS may present in the elderly population. The accumulative effect of the gradual degeneration of intervertebral foramen (stenosis) may lead to the compression of extraforaminal portion of the nerve root.

Computational simulation study on ilio-sacral screw fixations for pelvic ring injuries and implications in Asian sacrum

OBJECTIVES

Despite a high possibility of technique-related complications, ilio-sacral (IS) screw fixation is the mainstay of operative management in posterior pelvic ring injuries. We aimed to make IS screw trajectory with fully intraosseous path that was optimal and consistent, and confirm the possibility of transiliac-transsacral (TITS) screw fixation in Asian sacrum.

METHODS

Eighty-two cadaveric sacra (42 males and 40 females) were enrolled and underwent continuous 1.0-mm slice computed tomography (CT) scans. CT images were imported into Mimics^® software to reconstruct three-dimensional model of the pelvis. To simulate IS screws, we inserted 7.0-mm-sized TITS cylinder for first (S₁) and second (S₂) sacral segment and 7.0-mm oblique cylinder for S₁. TITS cylinder could not be inserted into S₁ of 14 models (sacral variation models) but could be inserted into the S₂ of all models. The actual length of virtual IS screws was measured, and anatomic features of safe zone (SZ_S2) including the area, horizontal distance (HD_S2), and vertical distance (VD_S2) were evaluated by the possibility of TITS screw fixation in the S₁.

RESULTS

When the oblique cylinder was directed toward the opposite upper corner of S₁ at the level of the first foramen, there was no cortical violation regardless of sacral variation. The average length of TITS cylinder was 152.3 mm (range 127.9-178.2 mm) in S₁ and 136.0 mm (range 97.8-164.1 mm) in S₂, and for oblique cylinder it was 99.2 mm (range 82.4-132.2 mm). The average VD_S2, HD_S2, and the area of SZ_S2 were 15.5 mm (range 8.7-24.4 mm), 18.3 mm (range 12.7-26.6 mm), and 221.1 mm² (range 91.1-386.7 mm²), respectively. The VD_S2 and SZ_S2 of sacral variation were significantly higher than those of normal (both p = 0.001).

CONCLUSIONS

Considering the high variability of the S₁, it is better to direct the IS screw trajectory toward the opposite upper corner of the S₁ at the level of first sacral foramen. If a TITS screw is needed, the transverse fixation for the S₂ could be performed alternatively due to its sufficient osseous site even in Asian sacrum.

Localizing the L5 Vertebra Using Nerve Morphology on MRI: An Accurate and Reliable Technique

BACKGROUND AND PURPOSE

Multiple methods have been used to determine the lumbar vertebral level on MR imaging, particularly when full spine imaging is unavailable. Because postmortem studies show 95% accuracy of numbering the lumbar vertebral bodies by counting the lumbar nerve roots, attention to lumbar nerve morphology on axial MR imaging can provide numbering clues. We sought to determine whether the L5 vertebra could be accurately localized by using nerve morphology on MR imaging.

MATERIALS AND METHODS

One hundred eight cases with full spine MR imaging were numbered from the C2 vertebral body to the sacrum with note of thoracolumbar and lumbosacral transitional states. The origin level of the L5 nerve and iliolumbar ligament were documented in all cases. The reference standard of numbering by full spine imaging was compared with the nerve morphology numbering method. Five blinded raters evaluated all lumbar MRIs with nerve morphology technique twice. Prevalence and bias-adjusted κ were used to measure interrater and intrarater reliability.

RESULTS

The L5 nerve arose from the 24th presacral vertebra (L5) in 106/108 cases. The percentage of perfect agreement with the reference standard was 98.1% (95% CI, 93.5%-99.8%), which was preserved in transitional and numeric variation states. The iliolumbar ligament localization method showed 83.3% (95% CI, 74.9%-89.8%) perfect agreement with the reference standard. Inter- and intrarater reliability when using the nerve morphology method was strong.

CONCLUSIONS

The exiting L5 nerve can allow accurate localization of the corresponding vertebrae, which is essential for preprocedure planning in cases where full spine imaging is not available. This neuroanatomic method displays higher agreement with the reference standard compared with previously described methods, with strong inter- and intrarater reliability.

Incorporation of Whole Spine Screening in Magnetic Resonance Imaging Protocols for Low Back Pain: A Valuable Addition

STUDY DESIGN

A retrospective review of lumbar magnetic resonance imaging (MRI) studies conducted at the Department of Radiodiagnosis & Imaging of a Tertiary Care Armed Forces Hospital between May 2014 and May 2016.

PURPOSE

To assess the advantages of incorporating sagittal screening of the whole spine in protocols for conventional lumbar spine MRI for patients presenting with low back pain.

OVERVIEW OF LITERATURE

Advances in MRI have resulted in faster examinations, particularly for patients with low back pain. The additional detection of incidental abnormalities on MRI helps to improve patient outcomes by providing a swifter definitive diagnosis. Because low back pain is extremely common, any change to the diagnostic and treatment approach has a significant impact on health care resources.

METHODS

We documented all additional incidental findings detected on sagittal screenings of the spine that were of clinical significance and would otherwise have been undiagnosed.

RESULTS

A total of 1,837 patients who met our inclusion criteria underwent MRI of the lumbar spine. The mean age of the study population was 45.7 years; 66.8% were men and 33.2% women. Approximately 26.7% of the patients were diagnosed with incidental findings. These included determining the level of indeterminate vertebrae, incidental findings of space-occupying lesions of the cervicothoracic spine, myelomalacic changes, and compression fractures at cervicothoracic levels.

CONCLUSIONS

We propose that T2-weighted sagittal screening of the whole spine be included as a routine sequence when imaging the lumbosacral spine for suspected degenerative pathology of the intervertebral discs.

Can the possibility of transverse iliosacral screw fixation for first sacral segment be predicted preoperatively? Results of a computational cadaveric study

OBJECTIVES

The purpose of this study was to predict the possibility of transverse iliosacral (TIS) screw fixation into the first sacral segment (S₁) and introduce practical anatomical variables using conventional computed tomography (CT) scans.

MATERIALS AND METHODS

A total of 82 cadaveric sacra (42 males and 40 females) were used for continuous 1.0-mm slice CT scans, which were imported into Mimics^® software to produce a three-dimensional pelvis model. The anterior height (BH) and superior width (BW) of the elevated sacral segment was measured, followed by verification of the safe zone (SZ_S1 and SZ_S2) in a true lateral view. Their vertical (VD_S1 and VD_S2) and horizontal (HD_S1 and HD_S2) distances were measured. VD_S1 less than 7mm was classified as impossible sacrum, since the transverse fixation of 7.0 mm-sized IS screw could not be done safely.

RESULTS

Fourteen models (16.7%; six females, eight males) were assigned as the impossible sacrum. There was no statistical significance regarding gender (p=0.626) and height (p=0.419). The average values were as follows: BW, 31.4mm (SD 2.9); BH, 16.7mm (SD 6.8); VD_S1, 13.4mm (SD 6.1); HD_S1, 22.5mm (SD 4.5); SZ_S1, 239.5mm² (SD 137.1); VD_S2, 15.5mm (SD 3.0); HD_S2, 18.3mm (SD 2.9); and SZ_S2, 221.1mm² (SD 68.5). Logistic regression analysis identified BH (p=0.001) and HD_S1 (p=0.02) as the only statistically significant variables to predict the possibility. Receiver operating characteristic curve analysis established a cut-off value for BH and HD_S1 of impossible sacrum of 20.6mm and 18.6mm, respectively.

CONCLUSION

BH and HD_S1 could be used to predict the possibility of TIS screw fixation. If the BH exceeds 20.6mm or HD_S1 is less than 18.6mm, TIS screw fixation for S₁ should not be undertaken because of narrowed SZ.

The Sommersdorf mummies-An interdisciplinary investigation on human remains from a 17th-19th century aristocratic crypt in southern Germany

Sommersdorf Castle (Bavaria, Germany) is a medieval castle complex which has been inhabited by the aristocratic family von Crailsheim. The deceased were entombed in a crypt located in the parapets underneath the castle’s church, resulting in mummification of the bodies. Based on the family chronicle and oral history, identities have been ascribed to the mummies. The aim of the study is therefore to test the accuracy of the historical records in comparison to archaeological, anthropological and genetic data. Today, the crypt houses eleven wooden coffins from the 17^th to 19^th century AD. In ten of these, mummified and scattered human remains were found. Archive records were studied in order to identify names, ancestry, titles, occupation, date of birth and death, and place of interment of the individuals. The coffins were visually inspected and dated by typo-chronology, and the mummified and scattered skeletal remains were subjected to a physical anthropological examination. In total, the crypt contains the remains of a minimum number of nine individuals, among them three adult males, five adult females and one infant. A detailed scientific examination, including prior conservation, ancient DNA analyses, and computed tomography (CT), was performed on five mummies. By means of the CT data age at death, sex, body height, pathologies, and anatomical variants were investigated. CT analysis further showed that the bodies were naturally mummified. Mitochondrial DNA analyses revealed that the tested individuals are not maternally related. In addition, health, living conditions and circumstances of death of the entombed individuals could be highlighted. Being confronted with the strengths, weaknesses and limitations of each methodological approach, probable identification was achieved in two cases.

Lumbosacral Transitional Vertebra: Possible Role in the Pathogenesis of Adolescent Lumbar Disc Herniation

OBJECTIVE

To investigate the role of lumbosacral transitional vertebra (LSTV) in the pathogenesis of adolescent lumbar disc herniation (ALDH) and the association between LSTV type and the herniation level of ALDH.

METHODS

This study was a retrospective case-control analysis of roentgenographic images. All adolescent patients who received surgical treatment for L4/5 or L5/S1 single level lumbar disc herniation in our department from 2010 to 2015 were eligible for the ALDH group. All adolescent patients admitted to our hospital during the same period and who had ever undergone a plain anteroposterior radiologic examination of the abdomen and met the inclusion criteria that ensured the absence of any spinal disorders were selected into the control group. The anteroposterior lumbar or abdomen roentgenograms were collected to identify the LSTV. The incidence of LSTV in the ALDH group and the control group were compared. Among the ALDH group, the association between LSTV type (sacralization or lumbarization) and the herniation level of ALDH were evaluated.

RESULTS

A total of 80 adolescent patients were included in the ALDH group and 92 asymptomatic adolescents were included in the control group. LSTV was found in 24 patients (30%) in ALDH group compared with 7 patients (7.6%) in the control group (P < 0.001; odds ratio, 5.2; 95% confidence interval 2.1, 12.9). Among the adolescent patients with sacralization, the L4/5 disc herniation was significantly more common than L5/S1 (81.3% vs. 18.7%; P = 0.019).

CONCLUSIONS

The LSTV is associated with LDH in adolescents and the sacralization of L5 may contribute to the L4/5 disc herniation in adolescent patients.

The Degenerative Spine

Degenerative disease of the spine is a leading cause of back pain and radiculopathy, and is a frequent indication for spine MR imaging. Disc degeneration, disc protrusion/herniation, discarhtrosis, spinal canal stenosis, and facet joint arthrosis, as well as interspinous processes arthrosis, may require an MR imaging workup. This review presents the MR imaging patterns of these diseases and describes the benefit of the MR imaging in these indications compared with the other imaging modalities like plain radiographs or computed tomography scan.

Role of Anatomical Landmarks in Identifying Normal and Transitional Vertebra in Lumbar Spine Magnetic Resonance Imaging

Study Design

Retrospective study.

Purpose

Identification of transitional vertebra is important in spine imaging, especially in presurgical planning. Pasted images of the whole spine obtained using high-field magnetic resonance imaging (MRI) are helpful in counting vertebrae and identifying transitional vertebrae. Counting vertebrae and identifying transitional vertebrae is challenging in isolated studies of lumbar spine and in studies conducted in low-field MRI. An incorrect evaluation may lead to wrong-level treatment. Here, we identify the location of different anatomical structures that can help in counting and identifying vertebrae.

Overview of Literature

Many studies have assessed the vertebral segments using various anatomical structures such as costal facets (CF), aortic bifurcation (AB), inferior vena cava confluence (IC), right renal artery (RRA), celiac trunk (CT), superior mesenteric artery root (SR), iliolumbar ligament (ILL) psoas muscle (PM) origin, and conus medullaris. However, none have yielded any consistent results.

Methods

We studied the locations of the anatomical structures CF, AB, IC, RRA, CT, SR, ILL, and PM in patients who underwent whole spine MRI at our department.

Results

In our study, 81.4% patients had normal spinal segmentation, 14.7% had sacralization, and 3.8% had lumbarization. Vascular landmarks had variable origin. There were caudal and cranial shifts with respect to lumbarization and sacralization. In 93.8% of cases in the normal group, ILL emerged from either L5 alone or the adjacent disc. In the sacralization group, ILL was commonly seen in L5. In the lumbarization group, ILL emerged from L5 and the adjacent disc (66.6%). CFs were identified at D12 in 96.9% and 91.7% of patients in the normal and lumbarization groups, respectively. The PM origin was observed from D12 or D12–L1 in most patients in the normal and sacralization groups.

Conclusions

CF, PM, and ILL were good identification markers for D12 and L5, but none were 100% accurate.

Anatomical differences in patients with lumbosacral transitional vertebrae and implications for minimally invasive spine surgery

OBJECTIVE

The objective of this study was to investigate the neurovascular and anatomical differences in patients with lumbosacral transitional vertebrae (LSTV) and the associated risk of neurovascular injury in minimally invasive spine surgery.

METHODS

The authors performed a retrospective study of CT and MR images of the lumbar spine obtained at their institution between 2010 and 2014. The following characteristics were evaluated: level of the iliac crest in relation to the L4–5 disc space, union level of the iliac veins and arteries in relation to the L4–5 disc space, distribution of the iliac veins and inferior vena cava according to the different Moro zones (A, I, II, III, IV, P) at the L4–5 disc space, and the location of the psoas muscle at the L4–5 disc space. The findings were compared with findings on images obtained in 28 age- and sex-matched patients without LSTV who underwent imaging studies during the same time period.

RESULTS

Twenty-eight patients (12 male, 16 female) with LSTV and the required imaging studies were identified; 28 age- and sex-matched patients who had undergone CT and MRI studies of the thoracic and lumbar spine imaging but did not have LSTV were selected for comparison (control group). The mean ages of the patients in the LSTV group and the control group were 52 and 49 years, respectively. The iliac crest was located at a mean distance of 12 mm above the L4–5 disc space in the LSTV group and 4 mm below the L4–5 disc space in the controls. The iliac vein union was located at a mean distance of 8 mm above the L4–5 disc space in the LSTV group and 2.7 mm below the L4–5 disc space in the controls. The iliac artery bifurcation was located at a mean distance of 23 mm above the L4–5 disc space in the LSTV group and 11 mm below the L4–5 disc space in controls. In patients with LSTV, the distribution of iliac vein locations was as follows: Zone A, 7.1%; Zone I only, 78.6%; Zone I encroaching into Zone II, 7.1%; and Zone II only, 7.1%. In the control group, the distribution was as follows: Zone A only, 17.9%; Zone A encroaching into Zone I, 75%; and Zone I only, 7.1%. There were no iliac vessels in Zone II in the control group. The psoas muscle was found to be rising away laterally and anteriorly from the vertebral body more often in patients with LSTV, resulting in the iliac veins being found in the “safe zone” only 14% of the time, greatly increasing the risk of vascular injury.

CONCLUSIONS

In patients with LSTV, the iliac crest is more likely to be above the L4–5 disc space, which increases the technical challenges of a lateral approach. The location of the psoas muscle rising away laterally and ventrally in patients with LSTV compared with controls and with the union of the iliac veins occurring more often above the L4–5 disc space increases the risk for iatrogenic vascular injury at the L4–5 level in this patient population.

Are Transitional Vertebra and Spina Bifida Occulta Related with Lumbar Disc Herniation and Clinical Parameters in Young Patients with Chronic Low Back Pain?

OBJECTIVE

Lumbosacral transitional vertebra (LSTV) and spina bifida occulta (SBO) are widespread within the lumbosacral spine. Their connection to lumbar disc herniation (LDH) and/or lower back pain has been debated in the current literature; however, there is no consensus. The purpose of this study is to evaluate the relationship between the frequency of LSTV and SBO with that of LDH among young patients with chronic lower back pain.

STUDY DESIGN

Cross-sectional.

MATERIALS AND METHODS

A total of 1094 patients with lower back pain, aged between 20 and 40 years, with lower back pain history persisting for longer than 12 weeks were studied. All the patients in the study were evaluated with standard pelvic radiographs and lumbar vertebra magnetic resonance imaging. The severity of pain was measured using the visual analog scale, and the effect of lower back pain on daily life activities was measured using the Oswestry disability index. The patients were separated into two groups: Group 1 consisted of patients without LDH, and Group 2 consisted of patients with LDH. Additionally, these two groups were separated into three subgroups: Non-LSTV-SBO, LSTV, and SBO.

RESULTS

It was determined that LSTV frequency was significantly higher (p=0.004) in the lumbar disc herniation group 2. In addition, the existence of LSTV increased the risk of lower back pain (p<0.001, p<0.001) and disability (p<0.001, p<0.001) in young patients with and without LDH or not. However, the presence of SBO did not increase lower back pain (p=0.251, p=0.200) and disability (p=0.134, p=0.161) in both groups.

CONCLUSION

A relationship was detected between the frequency of LDH and LSTV in young patients with chronic lower back pain between the ages of 20 and 40 years. Also, the presence of LSTV was found to increase the risk of lower back pain and disability.

Utility of the LevelCheck Algorithm for Decision Support in Vertebral Localization

STUDY DESIGN

An automatic radiographic labeling algorithm called "LevelCheck" was analyzed as a means of decision support for target localization in spine surgery. The potential clinical utility and scenarios in which LevelCheck is likely to be the most beneficial were assessed in a retrospective clinical data set (398 cases) in terms of expert consensus from a multi-reader study (three spine surgeons).

OBJECTIVE

The aim of this study was to evaluate the potential utility of the LevelCheck algorithm for vertebrae localization.

SUMMARY OF BACKGROUND DATA

Three hundred ninety-eight intraoperative radiographs and 178 preoperative computed tomographic (CT) images for patients undergoing spine surgery in cervical, thoracic, lumbar regions.

METHODS

Vertebral labels annotated in preoperative CT image were overlaid on intraoperative radiographs via 3D-2D registration. Three spine surgeons assessed the radiographs and LevelCheck labeling according to a questionnaire evaluating performance, utility, and suitability to surgical workflow. Geometric accuracy and registration run time were measured for each case.

RESULTS

LevelCheck was judged to be helpful in 42.2% of the cases (168/398), to improve confidence in 30.6% of the cases (122/398), and in no case diminished performance (0/398), supporting its potential as an independent check and assistant to decision support in spine surgery. The clinical contexts for which the method was judged most likely to be beneficial included the following scenarios: images with a lack of conspicuous anatomical landmarks; level counting across long spine segments; vertebrae obscured by other anatomy (e.g., shoulders); poor radiographic image quality; and anatomical variations/abnormalities. The method demonstrated 100% geometric accuracy (i.e., overlaid labels within the correct vertebral level in all cases) and did not introduce ambiguity in image interpretation.

CONCLUSION

LevelCheck is a potentially useful means of decision support in vertebral level localization in spine surgery.

LEVEL OF EVIDENCE

N/A.

Particularities of anterior fusion in L4-L5 isthmic spondylolisthesis

PURPOSE

L4-L5 isthmic spondylolisthesis may be associated with lumbosacral transitional vertebrae (LSTV) and altered venous vascular anatomy. The objectives of this study were to describe the anatomical characteristics of L4-L5 ISPL and the intraoperative difficulties encountered during the approach for anterior lumbar interbody fusion (ALIF).

METHODS

This is a retrospective review of 20 ALIFs for L4-L5 ISPL. The anatomy of the common iliac veins confluence and the position of L4-L5 with respect to the projection of the iliac crest were analysed on CT-scan. Intraoperative difficulties were noted.

RESULTS

A LSTV was present in 60% of cases, associated with abnormally distal positioning of L4-L5 below the projection of the iliac crest. The common iliac veins confluence was abnormally proximal compared to L4-L5. No complication was noted, even if the approach was unusually difficult in 11 cases.

DISCUSSION

Anterior lumbotomies are difficult because the left common iliac vein courses transversely across the left anterolateral aspect of the L4-L5 disc and L5 vertebral body, increasing the risk of vascular injury. Those difficulties have led us to abandon lumbotomies to treat L4-L5 ISPL to favour a pure anterior approach (midline) or an exclusive posterior approach.

LEVEL OF EVIDENCE

IV (retrospective study).

Conflicting calculations of pelvic incidence and pelvic tilt secondary to transitional lumbosacral anatomy (lumbarization of S-1): case report

Advancements in the understanding of adult spinal deformity have led to a greater awareness of the role of the pelvis in maintaining sagittal balance and alignment. Pelvic incidence has emerged as a key radiographic measure and should closely match lumbar lordosis. As proper measurement of the pelvic incidence requires accurate identification of the S-1 endplate, lumbosacral transitional anatomy may lead to errors. The purpose of this study is to demonstrate how lumbosacral transitional anatomy may lead to errors in the measurement of pelvic parameters. The current case highlights one of the potential complications that can be avoided with awareness. The authors report the case of a 61-year-old man who had undergone prior lumbar surgeries and then presented with symptomatic lumbar stenosis and sagittal malalignment. Radiographs showed a lumbarized S-1. Prior numbering of the segments in previous surgical and radiology reports led to a pelvic incidence calculation of 61°. Corrected numbering of the segments using the lumbarized S-1 endplate led to a pelvic incidence calculation of 48°. Without recognition of the lumbosacral anatomy, overcorrection of the lumbar lordosis might have led to negative sagittal balance and the propensity to develop proximal junction failure. This case illustrates that improper identification of lumbosacral transitional anatomy may lead to errors that could affect clinical outcome. Awareness of this potential error may help improve patient outcomes.

Patterns of congenital bony spinal deformity and associated neural anomalies on X-ray and magnetic resonance imaging

PURPOSE

Congenital malformations of the bony vertebral column are often accompanied by spinal cord anomalies; these observations have been reinforced with the use of magnetic resonance imaging (MRI). We hypothesized that the incidence of cord anomalies will increase as the number and complexity of bony vertebral abnormalities increases.

METHODS

All patients aged ≤13 years (n = 75) presenting to the pediatric spine clinic from 2003-2013 with congenital bony spinal deformity and both radiographs and MRI were analyzed retrospectively for bone and neural pathology. Chi-squared analysis was used to compare groups for categorical dependent variables. Independent t tests were used for continuous dependent variables. Significance was set at p < 0.05.

RESULTS

Fifty-five percent of congenital spine deformity patients (n = 41) had associated spinal cord anomalies on MRI. Complex bony abnormalities had a higher incidence of cord anomalies than simple abnormalities (67, 37 %; p = 0.011). Mixed deformities of segmentation and formation had a higher incidence of cord anomalies (73 %) than failures of formation (50 %) or segmentation (45 %) alone (p = 0.065). Deformities in the sacrococcygeal area had the highest rate of spinal cord anomalies (13 of 15 patients, 87 %). In 35 cases (47 %), MRI revealed additional bony anomalies that were not seen on the radiographs.

CONCLUSIONS

As the number of bony malformations increased, we found a higher incidence of cord anomalies. Clinicians should have increased suspicion of spinal cord pathology in the presence of mixed failures of segmentation and formation.

SPECT/CT bone scintigraphy to evaluate low back pain in young athletes: common and uncommon etiologies

Low back pain of various etiologies is a common clinical presentation in young athletes. In this article, we discuss the utility of SPECT/CT bone scintigraphy for the evaluation of low back pain in young athletes. The spectrum of lower spine lesions caused by sports injuries and identifiable on bone scan is presented along with strategies to avoid unnecessary irradiation of young patients. Also covered are pitfalls in diagnosis due to referred-pain phenomenon and normal skeletal variants specific to this age group.

The Clinical Significance of Lumbosacral Transitional Vertebrae on the Surgical Outcomes of Lumbar Discectomy: A Retrospective Cohort Study of Young Adults

OBJECTIVE

To evaluate whether the presence of lumbosacral transitional vertebrae (LSTV) affects the clinical outcomes of microdiscectomy (MD) in young adults with lumbar disc herniation.

METHODS

We retrospectively included 398 patients who were followed-up for at least 2 years after MD for lumbar disc herniation at L4/5 (disc above the LSTV). The patients were divided into 2 groups. Group A was made up of 31 patients in whom LSTV was detected. Group B, in contrast, was made up of 35 patients in whom LSTV was not detected. The LSTV were classified using plain radiographs and three-dimensional computed tomography by Castellvi et al. The primary outcome measure was pain intensity at each follow-up visit assessed with visual analog scale for back and leg. Secondary outcome measures included the Oswestry Disability Index, a 12-item short-form health survey for quality of life, complications, and recurrence rate.

RESULTS

After surgery, the visual analog scale scores for the back and leg decreased significantly in both groups. However, the back pain intensity in group A worsened at 12 and 24 months postoperatively. The Oswestry Disability Index scores and 12-item short-form health survey (both mental and physical) worsened at 12 and 24 months postoperatively in group A. Two cases of reherniation (6.5 %) were observed in group A, who required reoperation.

CONCLUSIONS

LSTV can limit a patient's clinical improvement after MD with regard to pain intensity and recurrence. Caution must be taken when a patient is scheduled to undergo surgery.

Effects of unilateral posteroanterior mobilization in subjects with sacralized lumbosacral transitional vertebrae

AIM OF THE STUDY

To find out the efficacy of unilateral posteroanterior (PA) mobilization over type IA and type IIA sacralized lumbosacral transitional vertebrae in patients with low back pain with or without leg pain.

RESEARCH DESIGN

experimental randomized control study.

SAMPLE SIZE

30 subjects,

SAMPLING

simple random sampling. GROUP A - 15 subjects - self lumbar mobility and stretching exercises + Unilateral PA mobilization + hot pack. GROUP B - 15 subjects - self lumbar mobility and stretching exercises + hot pack. Before initiating treatment, subjects were assessed for dependent variables: Pain intensity by VAS, Forward bending and side bending ROM by modified finger to floor method with the help of an inch-tape and functions by Modified Oswestry Functional Disability Questionnaires. Post test measurements were taken after completion 2 weeks of therapy. The results of the study suggest that unilateral PA pressure is an effective mobilization method in reducing low back pain, improving ROM and related disability as compared to impairment based exercises alone in patients with low back pain with or without radiation to lower limbs having abnormally large transverse processes and hypomobile type IA and IIA lumbo-sacral transitional vertebrae.

Degenerative disease of the lumbar spine

In the last 25 years, scientific research has brought about drastic changes in the concept of low back pain and its management. Most imaging findings, including degenerative changes, reflect anatomic peculiarities or the normal aging process and turn out to be clinically irrelevant; imaging tests have proven useful only when systemic disease is suspected or when surgery is indicated for persistent spinal cord or nerve root compression. The radiologic report should indicate the key points of nerve compression, bypassing inconsequential findings. Many treatments have proven inefficacious, and some have proven counterproductive, but they continue to be prescribed because patients want them and there are financial incentives for doing them. Following the guidelines that have proven effective for clinical management improves clinical outcomes, reduces iatrogenic complications, and decreases unjustified and wasteful healthcare expenditures.

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 %.

Effect of Anatomic Variability and Level of Approach on Perioperative Vascular Complications With Anterior Lumbar Interbody Fusion

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

The study aim was to determine the prevalence of vascular complications associated with anterior lumbar interbody fusion (ALIF) as a function of anatomic variation and the number of levels fused.

SUMMARY OF BACKGROUND DATA

ALIF often requires mobilization of the great vessels, particularly when exposing levels above L5-S1. The exposure can be more challenging in the setting of spondylolisthesis or transitional anatomy.

METHODS

This retrospective review of prospectively collected data from our spine database identified 204 patients who had undergone single level (n = 142) or multilevel (n = 62) ALIF from 2008 to 2013 with minimum 6-month follow-up. Average age was 58 years; 57% were female. Preoperative radiographic assessment for spondylolisthesis and transitional anatomy was performed. Body mass index, estimated blood loss, and levels of ALIF were recorded. Intraoperative vascular injury, postoperative deep venous thrombosis, and pulmonary embolism events were noted.

RESULTS

Eleven patients experienced postoperative thromboembolic events and were more likely to have had intraoperative vascular injury compared with patients who did not develop a vascular complication (36% and 5%, respectively; P = 0.004). Estimated blood loss was significantly higher in patients with spondylolisthesis when compared to patients without spondylolisthesis (520 cc vs. 103 cc, respectively; P = 0.017) or transitional anatomy (347 cc vs. 262 cc, respectively; P = 0.022). Patients undergoing multilevel ALIF had significantly higher blood loss than patients undergoing a single level procedure (684 cc vs. 107 cc; P < 0.001). Patient characteristics, blood loss, anatomic variation, and level of approach were not associated with the development of postoperative thromboembolic complications.

CONCLUSION

Performing ALIF in the setting of spondylolisthesis or transitional anatomy resulted in higher blood loss. Patients undergoing multilevel rather than single level ALIF experienced greater blood loss. Because patients with intraoperative vascular injury had increased likelihood of postoperative thromboembolic event, thrombosis prophylaxis should be considered in these patients.

LEVEL OF EVIDENCE

4.

Preoperative retrolisthesis as a risk factor of postdecompression lumbar disc herniation

OBJECT

In this study, the authors aimed to identify specific risk factors for postdecompression lumbar disc herniation (PDLDH) in patients who have not undergone discectomy and/or fusion.

METHODS

Between 2007 and 2012, 493 patients with lumbar spinal stenosis underwent bilateral partial laminectomy without discectomy and/or fusion in a single hospital. Eighteen patients (herniation group [H group]: 15 men, 3 women; mean age 65.1 years) developed acute sciatica as a result of PDLDH within 2 years after surgery. Ninety patients who did not develop postoperative acute sciatica were selected as a control group (C group: 75 men, 15 women; mean age 65.4 years). Patients in the C group were age and sex matched with those in the H group. The patients in the groups were also matched for decompression level, number of decompression levels, and surgery date. The radiographic variables measured included percentage of slippage, intervertebral angle, range of motion, lumbar lordosis, disc height, facet angle, extent of facet removal, facet degeneration, disc degeneration, and vertebral endplate degeneration. The threshold for PDLDH risk factors was evaluated using a continuous numerical variable and receiver operating characteristic curve analysis. The area under the curve was used to determine the diagnostic performance, and values greater than 0.75 were considered to represent good performance.

RESULTS

Multivariate analysis revealed that preoperative retrolisthesis during extension was the sole significant independent risk factor for PDLDH. The area under the curve for preoperative retrolisthesis during extension was 0.849; the cutoff value was estimated to be a retrolisthesis of 7.2% during extension.

CONCLUSIONS

The authors observed that bilateral partial laminectomy, performed along with the removal of the posterior support ligament, may not be suitable for lumbar spinal stenosis patients with preoperative retrolisthesis greater than 7.2% during extension.

Evaluation and Treatment of Low Back Pain: A Clinically Focused Review for Primary Care Specialists

Low back pain (LBP) is a leading cause of disability worldwide. In the absence of a classification system for pain syndromes, classification of LBP on the basis of the distribution of pain as axial (pain generally localized to the low back) or radicular neuropathic (pain radiating to the lower extremities) is relevant to clinical practice because the distribution of pain is often a corollary of frequently occurring disease processes involving the lumbar spine. Common sources of axial LBP include the intervertebral disc, facet joint, sacroiliac joint, and paraspinal musculature, whereas common sources of radicular pain include a herniated intervertebral disc and spinal stenosis. The accuracy of historical and physical examination findings has been established for sacroiliac joint pain, radiculopathy, and lumbar spinal stenosis. However, the accuracy of similar data, so-called red flags, for identifying the underlying medical sources of LBP has been overstated. Diagnostic imaging studies can be useful, and adherence to established guidelines can protect against overuse. Multiple pharmacological trials exist for the management of LBP; however, the long-term outcomes of commonly used drugs are mixed. For carefully selected patients with axial LBP, radiofrequency denervation techniques can provide sustained pain relief. In patients with radicular pain, transforaminal epidural steroid injections may provide short-term pain relief, but neurostimulation may confer more enduring benefits of refractory symptoms. Pain-related indications for commonly performed operations include spinal decompression for radicular symptoms as well as spinal fusion or disc prosthesis for discogenic LBP. Physical modalities and psychological treatments can improve pain and functioning, but patient preferences may influence treatment adherence.

Does Lumbosacral Transitional Vertebra Have Any Influence on Sacral Tilt?

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

To compare the sacral tilt (ST) angle between patients with and without lumbosacral transitional vertebra (LSTV).

SUMMARY OF BACKGROUND DATA

Although LSTV is a common malformation of the lumbosacral region, data regarding the effect of LSTV on the tilt of sacrum is limited.

METHODS

Anterioposterior and lateral lumbar radiographs of patients with low back pain performed between March 2013 and September 2013 were extracted from the medical electronic database. Among these radiographs, those belonging to patients with Castellvi types II, III, and IV LSTV were identified. The angle of ST was measured on lateral lumbar radiographs and compared with that of age- and sex-matched controls without LSTV.

RESULTS

Of the 1588 radiographs extracted from the database, 96 (6.1%) were positive in terms of Castellvi types II, III and IV LSTV. 85 of them were found to be eligible for analysis. Patients with LSTV had significantly smaller ST angle than those without LSTV (p = 0.000). However, this angle did not differ among types (II, III and IV) of LSTV (p = 0.788).

CONCLUSION

Results of this study revealed that patients with LSTV had less ST--that is to say more vertical sacrum-than those without this malformation.

LEVEL OF EVIDENCE

4.

Conus Medullaris Level in Vertebral Columns With Lumbosacral Transitional Vertebra

BACKGROUND

The estimated prevalence of lumbar or sacral transitional vertebrae (LSTV) in the population is 4% to 30%. Few small patient series have studied the normal level of the conus medullaris (CM) in individuals with LSTV.

OBJECTIVE

To determine, by using a large cohort of patients, whether individuals of all ages with LSTV have different CM positions in the spinal canal in comparison with the rest of the population with normal vertebral columns.

METHODS

We performed an institutional retrospective analysis of spinal magnetic resonance images on individuals with LSTV of all ages, sexes, and pathologies during a 10-year period. Fifty-seven percent of patients (n = 467) had a lumbarized vertebra and 43% had sacralized vertebra (n = 355). Mean age at the time of the study was 55 ± 19 years (range 1-97 years). Fifty-two percent were male and 48% were female. Sixty percent of subjects with a sacralized vertebra were female, and 54.5% of those with a lumbarized vertebra were male (P = .001).

RESULTS

The CM in individuals with a lumbarized vertebra was seen to be lower at L1-2 to L2s, than un those with a sacralized vertebra where most conuses were at T12-L1 to L1s (P ≤ 0.001). The CM level was similarly distributed among sexes and ages.

CONCLUSION

In our series, the CM level, when lumbarization occurred, was lower, with a mean level at L1-L2, whereas a more superior mean level at T12-L1 was seen when sacralization occurred. CM level was not influenced by sex, age, or pathology other than tethered cords.

The clinical importance of lumbosacral transitional vertebra in patients with adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective review of radiographs.

OBJECTIVE

The objective of this study was to (1) determine the prevalence of lumbosacral transitional vertebra (LSTV) with computed tomography (CT) and (2) correlate LSTV presence with lumbar disc degeneration at each level by magnetic resonance imaging.

SUMMARY OF BACKGROUND DATA

LSTV is a frequently observed abnormality. Although its prevalence in patients with adolescent idiopathic scoliosis (AIS) has been shown, no studies have yet examined the clinical importance of LSTV in patients with AIS.

METHODS

This study included 385 consecutive patients who underwent surgery for AIS at a single center. Plain radiographs and CT scans were used to detect LSTV. Disc degeneration was analyzed at the L3-4, L4-5, and L5-S1 disc levels with magnetic resonance imaging. The difference in disc degeneration at each level by the presence of LSTV was also analyzed. The effect of lumbar curve type on the disc degeneration of each level was then determined. To minimize confounding factors, logistic regression analysis was performed.

RESULTS

The overall prevalence of LSTV in patients with AIS confirmed by CT scans was 12.2% (47/385). The proportion of grade II or more disc degeneration at the L4-5 level was higher in the LSTV(+) group than in the LSTV(-) group (29.8% vs.19.2%) although it was not statistically significant (P = 0.093). Large lumbar curves showed a positive correlation with disc degeneration at the L5-S1 level (P = 0.022).

CONCLUSION

The prevalence of LSTV in patients with AIS was 12.2%. A trend of early degeneration in L4-5 level discs was found in patients with AIS with LSTV although it was not statistically confirmed. Disc degeneration at the L5-S1 level is related to a large lumbar curve. If patients with AIS with large lumbar curves have LSTV, consideration should be given to stopping the distal fusion at L3 instead of L4.

LEVEL OF EVIDENCE

4.

Localization and Segmentation of 3D Intervertebral Discs in MR Images by Data Driven Estimation

This paper addresses the problem of fully-automatic localization and segmentation of 3D intervertebral discs (IVDs) from MR images. Our method contains two steps, where we first localize the center of each IVD, and then segment IVDs by classifying image pixels around each disc center as foreground (disc) or background. The disc localization is done by estimating the image displacements from a set of randomly sampled 3D image patches to the disc center. The image displacements are estimated by jointly optimizing the training and test displacement values in a data-driven way, where we take into consideration both the training data and the geometric constraint on the test image. After the disc centers are localized, we segment the discs by classifying image pixels around disc centers as background or foreground. The classification is done in a similar data-driven approach as we used for localization, but in this segmentation case we are aiming to estimate the foreground/background probability of each pixel instead of the image displacements. In addition, an extra neighborhood smooth constraint is introduced to enforce the local smoothness of the label field. Our method is validated on 3D T2-weighted turbo spin echo MR images of 35 patients from two different studies. Experiments show that compared to state of the art, our method achieves better or comparable results. Specifically, we achieve for localization a mean error of 1.6-2.0 mm, and for segmentation a mean Dice metric of 85%-88% and a mean surface distance of 1.3-1.4 mm.

A Review of Symptomatic Lumbosacral Transitional Vertebrae: Bertolotti's Syndrome

BACKGROUND

Lumbosacral transitional vertebrae (LSTV) are increasingly recognized as a common anatomical variant associated with altered patterns of degenerative spine changes. This review will focus on the clinical significance of LSTV, disruptions in normal spine biomechanics, imaging techniques, diagnosis, and treatment.

METHODS

A Pubmed search using the specific key words "LSTV," "lumbosacral transitional vertebrae," and "Bertolotti's Syndrome" was performed. The resulting group of manuscripts from our search was evaluated.

RESULTS

LSTV are associated with alterations in biomechanics and anatomy of spinal and paraspinal structures, which have important implications on surgical approaches and techniques. LSTV are often inaccurately detected and classified on standard AP radiographs and MRI. The use of whole-spine images as well as geometric relationships between the sacrum and lumbar vertebra increase accuracy. Uncertainty regarding the cause, clinical significance, and treatment of LSTV persists. Some authors suggest an association between LSTV types II and IV and low back pain. Pseudoarticulation between the transverse process and the sacrum creates a "false joint" susceptible to arthritic changes and osteophyte formation potentially leading to nerve root entrapment. The diagnosis of symptomatic LSTV is considered with appropriate patient history, imaging studies, and diagnostic injections. A positive radionuclide study along with a positive effect from a local injection helps distinguish the transitional vertebra as a significant pain source. Surgical resection is reserved for a subgroup of LSTV patients who fail conservative treatment and whose pain is definitively attributed to the anomalous pseudoarticulation.

CONCLUSIONS

Due to the common finding of low back pain and the wide prevalence of LSTV in the general population, it is essential to differentiate between symptoms originating from an anomalous psuedoarticulation from other potential sources of low back pain. Further studies with larger sample sizes and longer follow-up time would better demonstrate the effectiveness of surgical resection and help guide treatment.

The Impact of Lumbosacral Transitional Vertebrae on Therapeutic Outcomes of Transforaminal Epidural Injection in Patients with Lumbar Disc Herniation

BACKGROUND

Although some studies have evaluated the clinical impact of lumbosacral transitional vertebrae (LSTV), few have attempted to determine an effective conservative treatment method for lumbar disc herniation (LDH) presenting concurrently with LSTV.

METHODS

We prospectively enrolled 291 consecutive patients who were followed-up for at least one year after transforaminal epidural injection (TFEI) for LDH. We confirmed the presence of LSTV with Paik et al.'s method, the Castellvi classification, and the Southworth and Bersack method. Clinical outcomes were evaluated with a visual analogue scale (VAS) for pain intensity and the Oswestry Disability Index (ODI) for functional status.

RESULTS

Of the 291 patients, 47 (16.2%) had LSTV, including 33 with sacralization and 14 with lumbarization, while 244 (83.8%) did not have LSTV. Patients in both groups improved significantly after TFEI in terms of the VAS (P < 0.001) and ODI (P < 0.001) scores. However, LDH patients with LSTV had a worse clinical outcome after six months of TFEI than did those without LSTV, with a significant difference between groups for both the VAS (P < 0.01) and ODI (P = 0.01) scores. LDH patients with sacralization had worse post-treatment clinical outcomes than LDH patients with lumbarization (P < 0.001) or LDH patients without LSTV (P < 0.001).

CONCLUSIONS

Sacralization can reduce the improvement after TFEI among LDH patients, while lumbarization appears to have no direct effect on TFEI outcomes. The presence of sacralization should be identified before TFEI, and if present, patients should be informed that the outcomes of TFEI may not be as good as they would be if sacralization was not present.

Transsacral screw safe zone size by sacral segmentation variations

Variations in sacral segmentation may preclude safe placement of transsacral screws for posterior pelvis fixation. We developed a novel automated 3D technique to determine the safe zone size for transsacral screws in the upper two sacral segments in 526 adult pelvis computed tomography scans. Safe zone sizes were then compared by gender and sacral segmentation variations (number of neuroforamen and the presence/absence of lumbosacral transitional vertebrae, ± LSTV). Ten millimeters was used as the safety threshold for a large screw. 3 (0.6%), 366 (70%), and 157 (30%) sacra had 3, 4, or 5 neuroforamen, respectively. Eighty-eight (17%) were +LSTV. Safe zone size depended on gender, number of neuroforamen in -LSTV sacra and presence of LSTV (p < 0.001) but not on the uni- or bilateral nature of the LSTV. 17% of -LSTV sacra were below the safety threshold in S1, 27% in S2, whereas 3% of +LSTV sacra were below in S1, 74% in S2. Of -LSTV sacra that cannot take an S1 screw safely, 77% can do so in S2, leaving only 4% of sacra that cannot accommodate a screw safely in either upper segment. The results demonstrate a predictable pattern of safe zone size based on gender and sacral segmentation variations.

Prevalence of lumbosacral transitional vertebrae in dogs in the Czech Republic

Lumbosacral transitional vertebra is a common congenital anomaly of the spine in dogs. It is a predisposing factor for degeneration of the lumbosacral spine and development of cauda equina syndrome or hip dysplasia in affected dogs. The aim of the study was to determine breed predisposition, types, and prevalence of lumbosacral transitional vertebrae in the canine population in the Czech Republic. The value of laterolateral radiographs of the lumbosacral junction in the diagnosis of LTV was also evaluated. Prevalence of lumbosacral transitional vertebrae was determined by reviewing ventrodorsal radiographs of pelvis with an extended hip of 1,878 dogs. Lumbosacral transitional vertebrae were detected in 188 dogs (10%). German Shepherd, Alaskan Malamute and Bohemian Shepherd were found to be highly predisposed breeds. The most common type of lumbosacral transitional vertebra was type II with separation of the first sacral vertebra from sacrum and presence of rudimentary intervertebral space between S1 and the sacral median crest (37.8% of the lumbosacral transitional vertebrae). Type I was detected in 29.2% and the asymmetric type of the lumbosacral transitional vertebra (type III) in 33%. Laterolateral radiograph of the lumbosacral spine was evaluated in 126 dogs from 188 with lumbosacral transitional vertebrae. Rudimentary intervertebral disc space between S1 and S2 in laterolateral radiographs was detected in 100% of lumbosacral transitional vertebrae with type II and III, and was not detected in type I. The findings on lumbosacral transitional vertebrae in the Czech Republic will extend knowledge about the disease. Both ventrodorsal hip-extended and laterolateral radiographs should be recommended for routine screening and reliable differentiation among the three different types of lumbosacral transitional vertebra.

Lumbosacral transitional vertebrae and its prevalence in the Australian population

Study Design Retrospective cohort study. Objective Lumbosacral transitional vertebrae (LSTV) are a common congenital anomaly, and they can be accurately identified on anteroposterior (AP) radiographs of the lumbosacral spine. This study attempts to determine the prevalence of this congenital anomaly and to increase awareness among all clinicians to reduce the risk of surgical and procedural errors in patients with LSTV. Methods A retrospective review of 5,941 AP and lateral lumbar radiographs was performed. Transitional vertebrae were identified and categorized under the Castellvi classification. Results The prevalence of LSTV in the study population was 9.9%. Lumbarized S1 and sacralized L5 were seen in 5.8 and 4.1% of patients, respectively. Conclusion LSTV are a common normal variant and can be a factor in spinal surgery at incorrect levels. It is essential that all clinicians are aware of this common congenital anomaly.

Abnormal rib count in scoliosis surgery: impact on the reporting of spinal fusion levels

PURPOSE

Variation in rib numbering has been noted in adolescent idiopathic scoliosis (AIS), but its effect on the reporting of fusion levels has not been studied. We hypothesized that vertebral numbering variations can lead to differing documentation of fusion levels.

METHODS

We examined the radiographs of 161 surgical AIS patients and 179 control patients without scoliosis. For AIS patients, the operative report of fusion levels was compared to conventional vertebral labeling from the first thoracic level and proceeding caudal. We defined normal counts as 12 thoracic (rib-bearing) and five lumbar (non-rib-bearing) vertebrae. We compared our counts with data from 181 anatomic specimens.

RESULTS

Among AIS patients, 22 (14 %) had an abnormal number of ribs and 29 (18 %) had either abnormal rib or lumbar count. In 12/29 (41 %) patients, the operative report differed from conventional labeling by one level, versus 3/132 (2 %) patients with normal numbering (p < 0.001). However, there were no cases seen of wrong fusion levels based on curve pattern. Among controls, 11 % had abnormal rib count (p = 0.41) compared to the rate in AIS. Anatomic specimen data did not differ in abnormal rib count (p = 1.0) or thoracolumbar pattern (p = 0.59).

CONCLUSIONS

The rate of numerical variations in the thoracolumbar vertebrae of AIS patients is equivalent to that in the general population. When variations in rib count are present, differences in numbering levels can occur. In the treatment of scoliosis, no wrong fusion levels were noted. However, for both scoliosis patients and the general population, we suggest adherence to conventional labeling to enhance clarity.