Partial Sacralization Left L5 Segment Is Again Appreciate

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A Review of Symptomatic Lumbosacral Transitional Vertebrae: Bertolotti'due south Syndrome

International Journal of Spine Surgery January 2015, 9 42; DOI: https://doi.org/ten.14444/2042

Abstract

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 primal 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 take of import implications on surgical approaches and techniques. LSTV are oft 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 accurateness. Uncertainty regarding the cause, clinical significance, and treatment of LSTV persists. Some authors advise an association between LSTV types II and IV and low back hurting. Pseudoarticulation betwixt the transverse process and the sacrum creates a "false articulation" susceptible to arthritic changes and osteophyte germination 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 forth with a positive effect from a local injection helps distinguish the transitional vertebra every bit a pregnant hurting source. Surgical resection is reserved for a subgroup of LSTV patients who fail conservative treatment and whose pain is definitively attributed to the dissonant pseudoarticulation.

Conclusions Due to the common finding of low back pain and the broad 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 amend demonstrate the effectiveness of surgical resection and help guide handling.

• LSTV
• Bertolotti's Syndrome
• transitional vertebrae

Introduction

Lumbosacral transitional vertebrae (LSTV) are congenital spinal anomalies, in which an elongated transverse procedure of the last lumbar vertebra fuses with varying caste to the "first" sacral segment.¹ LSTV, as a morphological variation, spans a spectrum from partial/complete L5 sacralization to partial/complete S1 lumbarization.^{2, three} When the L5 vertebra fuses completely to the sacrum, 4 lumbar vertebrae exist, whereas when S1 separates entirely from the sacrum, 6 lumbar vertebrae exist and the sagittal contour of the spine becomes more than lordotic.⁴ Many intermediate incomplete transitions accept likewise been recognized and classified as LSTV.⁵

Castellvi et al. classified LSTV into 4 types (Figure one). Blazon I includes unilateral (Ia) or bilateral (Ib) dysplastic transverse processes, measuring at least xix mm in width (craniocaudad dimension). Type II exhibits incomplete unilateral (IIa) or bilateral (IIb) lumbarization/sacralization with an enlarged transverse process that has a diarthrodial joint between itself and the sacrum. Type 3 LSTV describes unilateral (IIIa) or bilateral (IIIb) lumbarization/sacralization with complete osseous fusion of the transverse process(es) to the sacrum. Type 4 involves a unilateral type II transition with a type Iii on the contralateral side.^{3, six}

Estimates of the prevalence of LSTV in the general population vary widely throughout the literature due to differences in definition and diagnostic modalities, ranging from 4.0% -35.9% with a mean of 12.iii%.^{3, five, 7, 8} In a study of 211 participants, Apazidis et al. adamant Type IA most common with a prevalence of 14.7%;⁷ however, Blazon I is generally considered to have no clinical significance and does not require farther attending in clinical exercise.⁶ In an asymptomatic population, Nardo et al. determined that Type I and Type II were each responsible for more than 40% of full occurrences of LSTV, while Type Three and Blazon IV deemed for 11.five% and v.25% of occurrences, respectively.⁹ In unilaterally occurring malformations, the incidence is significantly higher on the left side, a finding which remains unexplained.¹⁰

The prevalence of LSTV is higher in men compared to women (28.ane% vs. 11.one%).⁹ Sacralization is more common in males, meanwhile accompaniment L5-S1 articulations and lumbarization of S1 are more common in women.¹¹ Cases of families with increased incidence of LSTV suggest a genetic component.12 HOX10/HOX11 genes influence axial blueprint of lumbar and sacral vertebrae. Mutations in these genes may play a function in the formation of LSTV.^five

Anatomical Variations

The presence of an LSTV disrupts normal spine biomechanics and anatomy. The sacrum, lying at the base of the vertebral cavalcade, optimizes the dissipation of the weight of the upper body toward the sacroiliac (SI) articulation past working every bit a fused mass of boney elements.^xi The sacrum's ability to dissipate load depends on its size and its surface area with the SI joint. Although HOX genes regulate sectionalisation of the vertebral column into individual vertebral segments, formation of transitional states at the lumbosacral junction may be greatly influenced by the functional requirements of load transmission at the SI junction. According to cadaver studies, sacra incorporating L5 possess significantly smaller heights than the normal sacra if the fused L5 vertebra is excluded from the measurement. This process of "improver" or "diminution" of segments to or from the sacrum depends on the load-bearing capacity of the normal (S1-S5) sacrum at a very rudimentary stage of its formation. Therefore, a small sacrum with inadequate SI articulation surface area may contain L5 to enhance load-bearing capacity, while a sacrum with over competent load bearing capacity may release S1.¹³

Boney abnormalities associated with LSTV impact surgery in the lumbosacral region. In the case of sacralization, all dimensions, including pedicle superlative, sagittal and transverse dimensions, and sagittal angulation are reduced, and downward gradient is increased. ^fourteen The meridian of the pars interarticularis (PI) and the widths of laminae are significantly smaller in the terminal lumbar segment of sacralized specimens. Minor PI may predispose spondylolysis and spondylolisthesis at lumbo-sacral junctions associated with transitional variations, and warrant special attention to avoid iatrogenic injuries.^xv Lumbarization of S1 results in a shorter distance between facet and sacral promontory, more obtuse pedicles in the sagittal airplane and less steep in front. Therefore, pedicle screws should be directed more obtusely in the sagittal aeroplane and at a reduced down inclination.^xiv LSTV possess a reduced number of trabeculae of cancellous bone. Consequently, screw placements and subsequent pullouts should be reviewed.¹⁶

LSTV exhibit altered articular facets at the L5-S1 junction such that the facets are smaller and more coronally oriented. Lumbarization results in the smallest facet linear dimension, smallest expanse, and maximal coronal orientation. Sacralization demonstrates insignificant alteration in facet morphology. Facet asymmetry is predominantly associated with accessory L5-S1 articulations, but is seen in all LSTV subtypes. These alterations are possibly related to depression back pain situations.¹⁷

The clan between LSTV with morphological alterations of neural arch elements and auricular surfaces is well established. Considering the biomechanical importance of these morphological alterations in maintaining stability of the lumbar spine, Mahato suggests re-defining and modifying the electric current classification of LSTV. Including facet and auricular surface condition would allow clinicians to clearly delineate the entire range of information required to visualize and clinically interpret any subtype of LSTV affliction (Table 1).²

Table 1

Redefining lumbosacral transitional vertebrae (LSTV) classification through integrating the full spectrum of morphological alterations in a biomechanical continuum.²

The disc elevation beneath a lumbosacral segment is significantly decreased in LSTV types II, 3, and IV.^{18, 19} The presence of a bilateral boney fusion decreases disc height more severely compared to segments with potential for motion (unilateral fusion). The common finding of a narrowed L5-S1 intervertebral disc associated with an LSTV should not be considered disk degeneration or displacement.¹⁹ In improver, the sagittal alignment is most ordinarily neutral, unlike the typical lordotic L5-S1 disc.

In an anatomical study of 70 cadavers, Aihara et al. establish that the iliolumbar ligaments at the level immediately higher up transitional vertebrae are thinner and weaker than those in cadavers without LSTV. The weak iliolumbar ligaments consequence in vertebral segment instability and could subsequently atomic number 82 to early disc degeneration. The germination of an articulation or boney union between vertebra and sacrum through the transverse process may represent an adaptive mechanism to compensate for a weak iliolumbar ligament and to preserve stability.²⁰

LSTV touch the terminal level of the conus medullaris (TLCM). Compared to controls, the TLCM is significantly higher in the presence of a sacralized L5 and significantly lower in the presence of a lumbardized S1. This finding may assistance clinicians identify the neurological discrepancies observed among neurologic injuries at the thoracolumbar junction. ²¹

In 1980, McCulloch and Waddell proposed that the functional L5 nerve root ever originates from the "last mobile" segment of the spine. The last mobile segment of the spine is defined equally the lowest level with a fully formed disc space, bilateral facet joints and ii free transverse processes which do not articulate with the ala of the sacrum or the pelvis. Therefore, in the example of a sacralized L5, the functional L5 nerve root corresponds to the anatomical L4 nerve root. In patients with a lumbardized S1, the concluding fully mobile level is commonly L6-S2, and the functional L5 nervus root corresponds with the L6 nerve root.²² Chang et al. agreed, concluding that neurologic symptoms caused by the L6 nerve root compression resemble those of the L5 rather than the S1 nerve root compression in the normal configuration. ²³ In 2008, Kim et al. suggested in the instance of lumbardized S1 (L6), the distribution of motor and sensory symptoms caused by the lumbardized S1 (L6) nerve root stimulation is similar to that of the S1 nerve root stimulation in the normal configuration.²⁴ Furthermore, Hinterdorfer et al. implemented intraoperative electrophysiological monitoring by means of evoked EMG to compare segmental innervation in patients with 5LVB and 6LVB. This study provides stiff evidence that the function of the lumbosacral nerve root is not significantly altered in patients with 6LVB, meaning that the L6 nerve root is equivalent to the S1 nerve root in patients with 5LVB. In improver, the root emerging from L6/S not only primarily resembles the S1 root but also shows characteristics of the S2 nerve, with a trend to innervate the biceps femoris muscle.²⁵ Seyfert, with careful use of cremasteric reflex, concluded that lumbarization shows a dermatome gap between the lumbar dermatomes C1-C3 and the sacral dermatomes S2 and S3, which lay significantly more ventral than in patients with a normal spinal configuration.²⁶ The alteration in nerve root innervation caused by a transitional vertebra may make information technology difficult to detect the pain generator. Therefore, in patients receiving epidurals or selective nerve root blocks, one should be aware of a transitional segment before initiating the injection. ²⁴

Lumbardized sacrums represent a relative contraindication for lateral transpsoas interbody fusion at L5-half dozen due to migration of neural anatomy inside the psoas musculus. Smith et al. reported that 8 out of ten patients with 6 lumbar vertebrae were converted to an alternative approach after a corridor through the psoas muscle was not constitute. Centric MRI reveals a teardrop-shaped psoas discrete from the lateral edge of the disc infinite in patients with transitional anatomy unapproachable at L5-6, resembling L5-S1 in normal beefcake. Preoperative axial MRI and intraoperative advanced neuromonitoring can help avoid injury.²⁷

Surgeons must consider the likelihood of vascular variation in the presence of an LSTV. According to Weiner et al., 11 out of 12 patients undergoing anterior lumbar interbody fusion at the functional junction above a fixed transitional level required pregnant alteration of the approach secondary to vascular variation. The more than caudal location of the junction between the mutual iliac veins and the inferior vena cava prohibits safe access to the functional L5-S1 disc beneath this junction. Appropriately, an approach lateral to the junction with mobilization of the left mutual iliac vein and inferior vena cava to the right of the midline is almost e'er required, similar to the approach to the L4-L5 disc.²⁸

Clinical Significance

Low back pain in the presence of an LSTV was originally noted by Mario Bertolotti in 1917 and termed "Bertolotti'southward Syndrome". According to Quinlan et al., the prevalence of Bertolotti'southward syndrome is 4.vi% in the full general population and xi.4% in patients under the age of 30.²⁹ Amongst 8280 patients seeking care for low back pain, Paik et al. found x.6% had LSTV types II, 3, or IV, with sacralization accounting for 5.three% and lumbarization accounting for 5.three%.⁵ Throughout the literature, the prevalence of LSTV in patients seeking care for low back pain ranges from iv.vi%-35.6%.^{7, 29} Due to its broad prevalence, Quinlan et al. encourages physicians to consider Bertolotti'due south syndrome in the differential diagnosis for low back pain, especially in younger patients.²⁹

The potential association between LSTV and low back pain has been debated since it was first described past Bertolotti almost a century ago.^five Amidst 4636 patients from the Osteoarthritis Initiative (OAI) cohort, Nardo et al. plant that 53.ix% of the patients without an LSTV reported depression back hurting. 46% of patients with a Blazon I and xl% of patients with a Type III LSTV reported low back hurting, suggesting these anomalies might be a protective factor. 73% of patients with Type 2 and 66% of patients with Type IV LSTV reported low back pain. Type 2 and Type IV LSTV positively correlate with increased prevalence and greater severity of low back and buttock pain and with lower physical activity levels.^{ix, thirty} Tang et al.'s recent study of 928 individuals with LSTV supported the association between Type Two LSTV with low back and gluteal pain, with respective odds ratios of 2.56 and v.38. The odds ratios for low dorsum and gluteal pain given the presence of a Blazon IV LSTV are four.28 and vi.82, respectively.^eight

Conversely, other authors believe that lumbosacral transitional segments are quite mutual in the general population and may not be seen with college prevalence in patients reporting depression back pain.⁷ In 1977, Tini et al. plant an insignificant divergence between incidence of LSTV in patients with low back hurting (half-dozen.seven%, n=4000) and in the general population (5%, due north=1873).¹² Several other studies constitute similar outcomes, concluding no difference in pain, disability level or neurological signs betwixt individuals with and without an LSTV.^{7, 18, 31–33}

A third opinion suggests that low back pain complaints might exist worse, but non more frequent in the presence of an LSTV. Worse hurting may result from the concentration of external stress on adjacent vertebral levels.^{34, 35} Among 881 immature male patients, Taskaynatan et al. reported that the presence of an LSTV increased the severity of the patient'southward clinical picture and severity of pain.³⁴ According to Yavuz et al., subjects with depression back pain and no malformation reported an average hurting level on the Visual Analog Scale for Hurting (VAS) of 2.2 versus 4.viii in patients with low dorsum hurting and a transitional vertebra.³⁵

Structural Pathologies

Bertolotti stated equally early equally 1917 that an LSTV may produce low back hurting due to arthritic changes occurring at the site of pseudoarthrosis.³⁶ Pain in the presence of an LSTV may also arise from disc herniation or degeneration, facet joint arthrosis, or spinal culvert or foraminal stenosis.^v In 1989, Elster et al.'southward radiographic study of 2000 patients suggested that the overall incidence of structural pathology, including significant disc protrusion, nerve root culvert stenosis, spondylolysis, and sclerosis at "false joints" is non appreciably higher in LSTV patients than in patients without such vertebrae.³⁷

Avimadje et al. constitute 52.7% of patients with a lumbar disc herniation also had an LSTV, while only 18.iii% of the control grouping had an LSTV.³⁸ Among patients with unilateral LSTV, 75.9% of the lumbar disc herniations occurred on the same side every bit the transitional vertebrae.³⁹ Patients with a transitional vertebra experience disc herniation more oftentimes (17% vs. xi%) and at a younger age (35 years old vs. 59 years old) compared to patients without a transitional vertebra. ³² Since historic period-related degenerative changes are common in the disc above a normal L5, the effect of transitional vertebrae may exist obscured in centre age. The possible increased prevalence of disc protrusion or extrusion above the transitional vertebra could lead to radiating pain as a event of nerve root compression and chemical irritation.¹⁸

The probability of finding LSTV in patients with clinically significant spinal symptoms is one.75 times college than in patients with non-spinal complaints. This probability increases to 2.3 times among patients with symptoms severe enough to crave an MRI and increases to three.half-dozen times among patients with last mobile disc herniation requiring discectomies. Therefore, information technology is possible to conclude that LSTV are more likely to be nowadays in patients with clinically significant spinal symptoms and fifty-fifty more than so in those operated on for disc herniation of the last mobile disc.⁴⁰

Although the association betwixt LSTV and pain continues to be debated, universal agreement throughout the literature describes an altered pattern of degenerative changes in patients with LSTV. Hypermobility and abnormal torque moments at the level immediately to a higher place the transitional vertebra and restricted movement betwixt the L5 and S1 vertebra result in degenerative changes at the level above the anomalous articulation.^{18, 20} Disc protrusion and/or extrusion occurs more often at the level supradjacent to the LSTV than at the aforementioned level in patients without an LSTV (45.3% vs. thirty.3%). This is also truthful for disc degeneration (52.eight% vs. 28%), facet degeneration (threescore.4% vs. 42.6%) and nervus root culvert stenosis (52.8% vs. 27.9%).⁴¹ Otani et al. reported 83% of patients with a disc herniation in the presence of an LSTV experienced symptoms arising from the last caudal mobile segment. Patients with disc herniation and no transitional vertebrae most frequently (59%) had symptoms arising from the 2nd last mobile segment. ³²

Disc bulge or herniation is exceedingly rare at the interspace below a transitional vertebra.^{20, 23, 32, 37, 39, 42} Increasing the mechanical connection of a lumbosacral transitional vertebra protects the disc at the transitional level. The greater the osseous bridging at the transitional level, the more than the transitional disc seems to exist preserved from degeneration.⁴³ The protective outcome of transitional vertebrae acts stronger on the annulus fibrosus than on either the nuclear complex or endplates. Overall, the effect of transitional vertebrae on the side by side discs may mimic the situation later a fusion operation when movement at 1 or more than disc spaces is restricted in relation to other disc levels.¹⁸

The incidence of spinal stenosis and spondylolysis is not significantly higher in patients with an LSTV.^{37, 44} However, the presence of an LSTV makes the magnitude of anterior slippage more severe. The greatest average slippage of L4 (19.iii%) occurs in sacralized patients. In lumbardized patients, the boilerplate slip of L4 is fourteen.5%, while in control groups, the average sideslip of L4 is11.4%.⁴⁵

Unilateral LSTV result in asymmetrical biomechanical alterations. The side begetting the additional L5/S1 relationship supports a larger proportion of load, resulting in lateral tipping of the iliac crest and convexity of a scoliotic curve towards the side of the articulation. The sacroiliac joint on the side of the LSTV will increment the auricular surface area, probably resulting in increased loading of that joint, greater article of clothing and irritation of the joint, greater fixation on exam, and increased 1 sided musculus activeness.⁴⁶ Asymmetry can cause early degenerative changes inside the normal contralateral facet joint, giving rising to facet pain.⁴⁷ Furthermore, asymmetrical move may also influence disc degeneration.⁴⁸

In Type Ii LSTV, the pseudoarticulation betwixt the transverse process and the sacrum creates a "false joint", in which degenerative changes accept occasionally been noted in clinical studies.⁴⁶ The presence of sclerotic changes and osteophytes near the fake articulation imply slight motion in these vertebrae. Initial studies suggested that the side with degenerative changes in the joint between the transverse procedure of the transitional vertebra and the pelvis do non correlate with the side of pain.³⁷ More recently, still, Connolly et al. demonstrated that eighty% of young patients with low back pain and an LSTV had high uptake on bone scintigraphy at the transverse-sacral articulation. The transverse-sacral articulation was the only abnormality in 63% of these depression back pain patients, suggesting that localized stress at the articulation contributes to low dorsum pain.⁴⁹

S1 lumbarization has been implicated in compression neuropathy of the S1 nerve root.^xiii The presence of an LSTV can result in pinching of a lumbar spinal nerve between the transverse process of the 5th lumbar vertebra and the sacral ala, a condition known as "Far-Out Syndrome."^50–52 Osteoporosis resulting from "micromotion" at dysplastic facet joints at the level below the transitional vertebra tin can issue in extraforaminal entrapment of the spinal nerve leading to radiculopathy.^fifty Neural compression by new bone formation below an LSTV occurs with a reported prevalence of 13% and can be symptomatic in up to 70% of these patients.⁵³

Imaging Lumbosacral Transitional Vertebrae

Nigh incorrect level surgical procedures occur in patients with numeric variant spines and/or LSTV.12 Spine physicians and radiologists must consider the possibility of numeric and morphological variations in lumbosacral images in gild to avoid intervention or surgery at the incorrect level.⁴² To determine the location of a specific vertebral body on a sagittal radiograph, the last vertebra with a rectangular shape is generally considered to be L5, then the vertebral bodies are numbered from the lesser to the tiptop. Still, in the presence of an LSTV the rectangular shaped last vertebra can be L4 or L6.⁵

The 30° angled AP radiograph (Ferguson radiograph) serves as the reference standard method to find LSTV (Effigy two). Sagittal images highlight transitional lumbosacral anatomy, such as "squaring" of the transitional vertebral trunk and reduced top of the transitional disc (Effigy 3). Axial images depict pseudoarthrosis or fusion of the terminal lumbar vertebra with the sacrum.¹

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Fig. two

Appearances of LSTV based on Castellvi et al. (a) Blazon 1b with bilaterally enlarged L5 transverse procedure only no articulation with the sacrum. (b) Type 2a with unilateral pseudarthrosis. (c) Type 2b with bilateral pseudarthroses. (d) Blazon 3a with unilateral fusion of the enlarged transverse process to the sacral ala. (e) Blazon 3b with bilateral fusion. (f) Blazon four appearance with fusion on the left side and a pseudarthrosis on the right.¹

Standard AP radiographs demonstrate 76%-84% accuracy for LSTV detection and 53%-58% accuracy to classify LSTV. Diagnostic errors in identification of vertebral levels on sagittal lumbar MRI are also common. ⁴³ Co-ordinate to Tokgoz et al., 1.3% of patients with normal segmentation were misdiagnosed on MRI as having an LSTV, 35.1% of the patients with an LSTV were misdiagnosed as having normal sectionalization, and threescore% of the patients with a correctly diagnosed LSTV had an incorrect number of vertebral levels.⁵⁴

O'Driscoll et al. classified iv types of lumbosacral junctions based on sagittal T1/T2 lumbar spine MRIs. In Type 1 no disc material is present. Type 2 denotes a small residual disc not extending for the whole AP diameter of the sacrum. Type 3 represents a well-formed disc extending for the whole AP diameter of the sacrum, while Type four is identical to Type 3 but with an abnormal upper sacral outline analogous to the "squaring" appearance on sagittal radiographs. Type four correlates with a fused LSTV (Castellvi Blazon 3 or Blazon IV).⁵⁵ Furthermore, Desmond et al. utilized sagittal T2-weighted spinecho MRI in patients with LSTV to classify the transitional disc as Type i or Type 2. A Type 1 transitional disc is smaller than the disc at the side by side mobile segment, maintains T2-weighted signal intensity, lacks an intra-nuclear cleft, shows no testify of fusion between anterior vertebral torso endplates and assembly with the pseudoarthrosis of the transverse vertebra of the LSTV to the sacrum. A Type 2 transitional disc is smaller than Blazon one, maintains its point intensity, lacks an intra-nuclear scissure, shows testify of anterior endplate fusion and concave endplates to the disc and is associated with the consummate fusion of the LSTV to the sacrum.⁵⁶

LSTV patients oft demonstrate exaggerated lumbar lordotic curvature and a lack of precipitous angulations at the lumbosacral junction on mid-sagittal MRI. An bending formed by a line parallel to the superior surface of the sacrum and a line perpendicular to the axis of the scan table on mid-sagittal T2-weighted MRI >39.8° predicts the presence of an LSTV with eighty% sensitivity and 80% specificity. In addition, an angle formed by a line parallel to the superior endplate of the L3 vertebra and a line parallel to the superior surface of the sacrum >35.nine° predicts the presence of an LSTV with 80% sensitivity and 54% specificity. ⁴⁸ It should be noted that the magnitude of the angle formed between the lumbosacral junction vertebral endplates (lumbosacral intervertebral disc bending) is not a useful diagnostic tool.⁵⁷

Farshad et al. abet measuring the differences per segment of the vertical mid-vertebral angle (Diff-VMVA) and the vertical anterior vertebral angle (Unequal-VAVA) of the iii most caudal segments of the lumbar spine to merely and reliably place LSTV. A Diff-VMVA of ≤ +10° identified type Iii and Four LSTV with a sensitivity of 100% and a specificity of 89% on MRI and with a sensitivity of 94% and a specificity of 74% on lateral radiograph. In terms of Unequal-VAVA, a sensitivity of 100% and a specificity of 76% were achieved with a cut-off value of 28°.⁵⁸

Paik et al. suggest routinely calculation sagittal T2W images to the lumbar MRI protocol and thoracolumbar sagittal T2W images to the cervical MRI protocol. In addition to screening of circumstantial lesions, wholespine sagittal T2W images play an essential role in accurate vertebral numbering. Numbering caudally from C2 on whole-spine MR images and utilizing morphological classification past Castellvi enables proper identification of both numeric and morphological vertebral variations (Figure four).^five Plain radiographs of the thoracolumbar junction enable hypoplastic true ribs to be differentiated from big transverse processes and therefore enable correct identification of the L1 vertebral trunk.^{22, 57}

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Fig. 4

A instance of L6 vertebra with blazon IIa transition. Left, T2-weighted sagittal cervicothoracic and (correct) lumbar images in the cross-referencing fashion of the movie archiving and communication system. This simultaneously demonstrates the marking at the T12–L1 disc space. Counting the vertebral levels caudally from C2 reveals this patient to accept 25 presacral vertebrae or 6 lumbar vertebrae.⁵

Milicic et al. advise that the suspicion of an LSTV in a child requires sagittal images of the sacrum and coccygeal bone on T2 weighted sequence in addition to MR imaging scans of the lumbosacral spine. The clinician should count upwards from S5 and precisely determine S1. Conclusion of S1 enables detection of the L5 and, in plow, all other vertebrae.⁵⁹

Paraspinal structures in positions outside their frequent location may signify the presence of a transitional vertebra. On sagittal images, the aortic bifurcation, IVC confluence, right renal artery, celiac trunk, and superior mesenteric artery root are located ane-3 levels more caudal than normal in the case of lumbarization, and 1-iii levels more cephalic than normal in the instance of sacralization.⁶⁰ Nonspinal anatomic landmarks are problematic, still, because of their variable location and potential changes with age.⁵⁷

Although Hughes et al. concluded that the iliolumbar ligament e'er arises from L5,⁶¹ a more accurate conclusion of their research would be that the iliolumbar ligament arises from the concluding lumbar vertebra, which could be L4, L5, or L6, depending on the segmentation of the spine.⁶² Therefore, the iliolumbar ligament does not permit for absolute numbering of the vertebral cavalcade and the iliolumbar ligament is not a consistent tool to number the spine, as information technology does not e'er signal the L5 level.⁵⁷

An anomalous number of presacral vertebrae is 7x more probable in the presence of an LSTV. In improver, the presence of an LSTV is associated with a college incidence of a concomitant thoracolumbar TV (TLTV) and vice versa. Identification of an LSTV should prompt boosted imaging to verify numbering, particularly if an intervention is contemplated. Clinicians should retrieve that no landmark is consistentlyreliable, so an explicit statement regarding how the lumbosacral junction was determined must be made in the imaging report.⁵⁷

Diagnosis And Treatment Of Bertolotti'S Syndrome

Low back hurting is a prevalent problem with multiple causes. Approximately 80% of adults seek a physician's help for low back pain at some point in their lives. Given the wide prevalence of LSTV, information technology is important that depression back pain in the presence of an LSTV is not automatically attributed to the radiographic finding of an enlarged transverse process.⁶³ A diagnosis of Bertolotti's syndrome should exist cautiously considered with appropriate patient history, imaging studies, and diagnostic injections.⁶⁴ Every bit with other causes of low back pain, the initial treatment of symptomatic LSTV is clinical, including a combination of NSAIDS and rehabilitative physical therapy.⁶⁵ There is a lack of consensus, however, regarding the handling of this condition, and the number of studies and instance reports in the literature reporting on the diagnosis and outcomes of patients with symptomatic LSTV is sparse.^{64, 66}

The literature includes 4 reports of either chiropractic direction or physical therapy to treat symptomatic LSTV. Muir et al. reported 2 patients with Castellvi Type IIa LSTV presenting with limited ipsilateral flexion coincided with ipsilateral muscular symptomatology similar to piriformis syndrome. 1 patient experienced 70% improvement in symptoms afterwards ii weeks of spinal manipulation, soft tissue therapies, practice and stretching. The other patient reported comeback in pain and perceived mobility after 4 weeks of similar handling.⁶⁶ 2 additional case reports described patients with low back pain and an LSTV that resolved following spinal manipulation, stretching and practice.^{67, 68} The authors proposed that the decreased mobility at the L5/S1 junction brought on by an LSTV results in biomechanical changes and contradistinct weight distribution at this level. These changes increment stress on the muscles in the region of the sacroiliac and lumbosacral junction on the affected side. Therefore, the authors indicated a role for conservative care in patients with LSTV, not to relieve pressure on an impinged nerve, but instead to address muscular alterations in the lumbopelvic musculature.⁶⁶

Because of its simplicity, low expense, and wide availability, functional flexion-extension radiography is the nearly thoroughly studied and the nearly widely used method in the imaging diagnosis of lumbar intervertebral instability. Flexion-extension lateral views allow measurement of the sagittal translation of a vertebra with respect to the underlying one and the amount of vertebral rotation in the sagittal airplane.⁶⁹ According to Little et al., strengthening and stabilizing exercises probably take moderate benefit on patients with low back pain associated with abnormal motion patterns identified on dynamic x-ray studies.^lxx Lessons in the Alexander technique offering an individualized arroyo to develop skills that aid patients recognize, understand, and avoid poor habits affecting postural tone and neuromuscular coordination. Footling et al. randomized 579 patients with recurrent low back pain to normal care, to vi Alexander technique lessons, or to 24 Alexander lessons. 24 lessons in the Alexander technique taught by registered teachers provided long-term benefits for patients with chronic or recurrent depression back pain. The authors reported changes in postural tone and changes in load and position. These findings supported the hypothesis that the Alexander technique could potentially reduce back pain by limiting musculus spasm, strengthening postural muscles, improving coordination and flexibility, and decompressing the spine.⁷⁰ Several studies take also examined the effects of Pilates method in people with chronic depression dorsum pain. The literature defines Pilates method equally a mind-body exercise that focuses on core stability, muscle control, breathing, strength, flexibility, and posture. Pilates method involves conscious use of trunk muscles to stabilize the pelvic-lumbar region. The electric current consensus suggests that Pilates methodbased exercises are more effective than no treatment or minimal physical do interventions in the management of chronic low back hurting.⁷¹

L4/5 articulation radiofrequency sensory ablation has been reported to provide 100% relief of buttock pain for sixteen months in one patient with an LSTV.⁷² Additionally, Endo et al. reported immediate disappearance of low back pain in a patient with an LSTV following electric denervation of the space betwixt the transverse process of the 5th lumbar vertebra and the sacral ala. The authors advocated electric denervation as a minimally invasive and potentially constructive method for pain eradication.⁷³

Injections of steroids or local anesthetics into the transverse process pseudoarticulation site tin can be both diagnostic and provide immediate, albeit temporary, pain relief.⁶⁴ Almeida et al. advocated performing these blocks with a minimal amount of coldhearted delivered precisely to the betoken of interest.⁶⁵ Mitra et al. reported an improved Oswestry score from 33 to 26 in a 64-year-sometime female with a Type IIb LSTV 1 month post-obit a local anesthetic and corticosteroid injection administered to the transverse procedure-ilium joint.⁷⁴ In a retrospective study of 12 patients with unilateral lumbo-sacral dissonant articulation with aforementioned side low back or buttock pain, 9 patients reported a l% decrease in pain after 1 month. 7 out of 8 patients who were re-evaluated 24 months later improved or were symptom free.³⁸ Marks et al. reported that vii out of 10 patients with chronic low back pain and an dissonant lumbosacral articulation obtained worthwhile relief later on steroid injection of the anomalous lumbosacral articulation and 1 patient remained hurting complimentary at 24 months.⁷⁵

A diagnostic injection at the pseudoarticulation site not merely provides pain relief but also helps determine if the LSTV is a significant source of the patient'south low back pain and radicular symptoms. Li et al. relied on patient response to injection as an exclusionary test for surgery. Specifically, if the injection did not provide relief, the patient was not considered a surgical candidate. Discography may be useful if the disc higher up the transitional vertebra is thought to be the source of the pain.⁶³

Bone scintigraphy complements the evaluation of patients with depression back pain thought to ascend from LSTV articulations. LSTV articulations increase uptake on bone scintigraphy secondary to degeneration and metabolic activity of the anomalous articulation (Figure 5). Pekindil et al. evaluated 28 patients in whom a lumbosacral transitional vertebral articulation had been identified radiographically. On planar imaging, normal-to-minimally and normal-to-moderately non-focal increased uptake was observed in patients without degenerative changes and with degenerative changes, respectively. The authors stated that when increased uptake is seen on the upper 1/2 to 1/iii part of the sacroiliac joint on planar images, this should non exist mistaken for sacroiliac joint affliction and degenerative LSTV articulations should peculiarly be considered in the differential diagnosis. On SPECT imaging, the patients who had no degenerative changes at the dissonant joint had non-focal balmy uptake. However, in symptomatic patients with degenerative changes in which no crusade was found for low back pain by clinical, laboratory, CT and os SPECT examinations, in that location was focal markedly increased uptake on SPECT imaging. The authors advocated that focal, markedly increased uptake may show the metabolically agile degenerative changes of LSTV articulation and may aid to reveal pain arising from LSTV articulations.⁷⁶

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Fig. five

Female patient age 62 with depression back pain and with degenerative type IIA LSTV articulation (arrows) on the right side on apparently motion picture. (B) Non-focal, moderately increased uptake (big pointer) on the upper sacroiliac joint area at the planar scan. Note also the not-focal, minimal, tracer activity (modest arrow) respective to the right enlarged transverse process. (C) Coronal SPECT image demonstrates focal, markedly increased activity (pointer) located in the degenerative dissonant joint area. This patient was diagnosed equally having active degenerative affliction.⁶³

Almeida et al. proposed a diagnostic-therapeutic algorithm based on the clinical and surgical feel they acquired treating five patients with low back pain in the presence of an LSTV (Figure 6). These 5 patients did not ameliorate with clinical handling, including non-steroidal anti-inflammatory drugs (NSAIDS), physiotherapy and physical exercises. The patients were submitted to an coldhearted block at the contact of the mega-apophysis with the sacrum, which provided temporary pain relief in all 5 patients. Thereafter, they underwent radiofrequency neurolysis, whereby 3 patients experienced simply a partial command of the hurting and ii experienced meaning improvement. The latter 2 patients underwent mega-apophysis surgical resection and achieved complete resolution of symptoms during the ane year follow upwards. The authors recommended considering mega-apophysis surgical resection for the sub-group of patients with low dorsum pain and LSTV who fail conservative handling, only feel temporary relief with anesthetic block. Other associated causes of low back pain should be considered if coldhearted block of the anomalous articulation does not provide pain relief.⁶⁵

Jonsson et al. described 11 patients with low dorsum pain ipsilateral to an LSTV. None of the patients had signs or symptoms of lumbar nervus root compression. nine out of the 10 patients who had an injection of local anesthetic into the anomalous joint experienced pain reduction or alleviation. These 9 patients subsequently underwent resection of the abnormal joint. At 6 to 42 months postoperatively, 7 patients reported total alleviation of pain, and two experienced meaning comeback.⁷⁷

Santavirta et al. surgically treated sixteen patients with radiographically diagnosed LSTV and chronic, persistent depression dorsum pain with either posterolateral fusion or resection of the transitional articulation. 10 of the 16 operatively treated patients showed improvement of their low back hurting. The results were similar in the group treated with fusion and in the group treated with resection. eleven patients had persisting episodes of sciatica (versus 13 preoperatively). At follow-up the first disc above the fused segment was found to be degenerative in seven out of eight cases, and in the group treated with resection the beginning disc above the transitional vertebra was degenerated in 5 out of 8 cases. three patients from each grouping were treated with second operations. Compared to xvi conservatively treated controls, the operatively treated patients had slightly better Oswestry pain scores, however the total Oswestry inability calibration scores did not differ. Given that the results of surgical handling were simply slightly better than conservative handling, the authors suggested operative treatment in only very select patients who should be advisedly examined for disc pathology. The authors recommended resection if the patient's pain can be definitively attributed to the transitional joint, conservative treatment fails, and no disc pathology tin can be detected. Posterolateral fusion may be considered if the transitional disc is degenerated, and the disc to a higher place the transitional vertebra is intact.⁷⁸

Ugokwe et al. achieved 97% pain resolution in one patient with a minimally invasive approach to resect an enlarged transverse process and the accompanying anomalous pseudoarticulation at the L5 level. The same authors published the results of seven patients who underwent minimally invasive paramedian tubular-based resection of symptomatic LSTV. The mean age at the time of surgery was 43.3 years and the mean historic period at diagnosis of Bertolotti's syndrome was twoscore.2 years. The median elapsing of low-back pain and/or radicular symptoms was 8 years prior to surgery. 3 of 7 patients reported complete resolution of depression back hurting, 2 of 7 patients had reduced low-back hurting, and 2 patients experienced initial relief but return of low-back pain at ane and 4 years postoperatively. three of the vi patients with radicular pain had complete relief of this symptom.⁶⁴

Only 8 cases of impingement of a nerve root by a bony spur at the articulation between the transverse process of a transitional vertebra and the sacrum have been reported in the literature. 6 of these patients underwent surgical intervention. In a patient described by Abe et al, MRI revealed mild degenerative changes with minimal posterior disc bulging and impingement of the left L5 nervus root by bony spur formation at the anterior exit zone of the nerve root foramen below a transitional vertebra. Selective nervus root sheath infiltration of the left L5 nerve root was performed. The patient's hurting was reproduced over the same surface area of the left leg during insertion of the needle. Immediately after the injection of a 2-mL solution of 2% lidocaine hydrochloride with contrast, these symptoms completely disappeared. Selective radiculography demonstrated foraminal impingement of the nerve root betwixt the lateral bony spur and the medial intervertebral disc. Given that 3 lesions demonstrated by MRI could accept been the symptomatic lesion, selective radiculography proved useful in differentiating the symptomatic lesion of the nerve root. The authors then performed an anterior decompression (left-sided, muscle splitting, extra peritoneal arroyo/Fraser's Incision), which resulted in complete resolution of back hurting and numbness by the follow-upward examination i year after surgery.⁵¹ Kikuchi et al reported two boosted cases of inductive decompression for far-out syndrome below a transitional vertebra. Anterior decompression was performed for both cases using a Fraser incision and resulted in successful resolution of symptoms. The authors advocated anterior decompression for cases of far-out syndrome refractory to selective nerve root block, explaining that this approach allows for a more complete decompression in the context of entrapment more inductive of the exit zone of the foramen compared to other pathologies. The authors stated that it would take been difficult to obtain a wide, well-illuminated, and dry surgical field from the posterior arroyo.^{51, 79}

Ichihara et al. however, reported no difficulty with decompression using a posterior arroyo for one patient who obtained good relief of radicular pain. The authors described posterior decompression equally an easy, safe, and useful treatment for radicular pain acquired by an L5 nerve far-out syndrome when conservative treatments neglect to obtain good relief.⁵²Weber and Ernestus reported a patient with radicular pain and a unilateral anomaly of the right transverse procedure of L5 resulting in foraminal stenosis of the L5 spinal nervus and, specially, entrapment outside the foramen between the big transverse process of the sacral ala. Following foraminal and extraforaminal decompression of the nerve via an extraforaminal approach, the patient reported no radicular or lumbar pain at 12 months follow upwardly.^l Miyoshi et al. employed selective radiculography and nerve root block followed by computed tomography to highlight foraminal entrapment of the L5 nerve root via osteophytes below a transitional vertebra. The patient underwent posterior decompression past resection of the osteophytes using an operating microscope and the patient experienced good relief of radicular pain. The authors emphasized that selective radiculography is the most reliable modality to diagnose far-out entrapment of the L5 nerve root and that CT in combination with radiculography clearly demonstrates not only the degree of L5 nerve root impingement, only also the etiology of the L5 nerve root compression.^fourscore

Shibayama et al. described a patient with an enlarged correct-sided transverse process at L6, moderate compression of the dural sac on the right side at L5-6, and mild compression of the right L6 spinal nerve. Although microendoscopic decompression of the spinal canal provided little relief, extraforaminal decompression of correct L6 relieved both low dorsum pain and sciatica. The authors suggested that intractable sciatica secondary to an enlarged transverse process could arise from impingement of the nerve root extraforaminaly rather than betwixt the transverse process and the sacrum.⁸¹ It is frequently difficult to differentiate symptomatic and asymptomatic extraforaminal stenosis secondary to osteophyte formation on conventional MRI lonely. With the use of 3D MR lumbosacral radiculography, Byun et al. associated indentation or swelling at the L5 nerve root with symptomatic extraforaminal stenosis. These radiographic findings were distinctively absent in cases of asymptomatic extraforaminal stenosis.⁸²

Resection of a correct-sided unilateral anomalous lumbosacral articulation provided 90% relief of left low back hurting and complete relief of left leg symptoms in i patient with a contralateral symptomatic L6-S1 facet joint. The authors suggested that the patient'southward pain was non associated with the anomalous articulation itself, simply was probably due to additional stress placed on the normal contralateral joint. In this case, pain relief resulted from reduced stress on the symptomatic facet.⁴⁷

Conclusions

Although Bertolotti's syndrome was first described well-nigh a century ago, contend continues regarding the prevalence, clinical significance, radiographic identification and treatment of symptomatic LSTV. While early studies depicted LSTV equally a rare anatomical anomaly, studies incorporating revised definitions and improved imaging techniques suggest LSTV may be nowadays in upwards to 35.ix% percent of the general population.⁷

The formation of an LSTV may serve as a compensatory response to inadequate load bearing capacity of the sacrum^xiii or spinal instability secondary to weak iliolumbar ligaments.²⁰ The resulting morphological alterations have important implications on spine surgery. Almost wrong level surgical procedures occur in patients with numeric variant spines or LSTV.¹² Changes of neural arch elements and auricular surfaces complicate the placement of pedicle screws in an LSTV.^{14, 16} Lumbar interbody fusion at the junction above a stock-still transitional level requires an alternative approach due to migration of neuronal anatomy within the psoas muscle and the more caudal location of the junction between the common iliac veins and inferior vena cava.^{27, 28}

Spine physicians must identify the presence of LSTV prior to surgical intervention. The Ferguson radiograph serves every bit the reference standard method to detect LSTV, though diagnostic errors and inaccurate identification of vertebral levels on both standard radiographs and MRI are common.⁴³ The use of whole-spine images as well as geometric relationships between the sacrum and lumbar vertebra help increase accuracy.^{5, 57, 58}

Investigations regarding the association between LSTV and clinically pregnant low dorsum pain accept yielded inconsistent and conflicting results. Throughout the literature, Type II and Type IV are most consistently associated with back and buttock pain and decreased physical activity levels.^{ix, 30} Symptoms associated with LSTV Blazon II potentially ascend from degenerative changes in the pseudoarticulation between the transverse process and the pelvis.⁴⁶ The formation of osteophytes in these "false joints" can cause nerve root compression.⁵³ Disc herniation and degeneration almost always occur at the level supradjacent to the LSTV and may occur more ofttimes and at younger ages than in individuals without an LSTV.^{18, xx, 32}

The pathophysiology of Bertolotti's syndrome remains obscure and there is no consensus nigh the most advisable therapy for each patient. Due to its multifactorial causes and the mutual findings of low dorsum pain in the general population, it is essential to differentiate low back pain acquired by transverse mega-apophysis contact with the sacrum from other sources of dorsum pain in patients with LSTV.⁶⁵ A positive radionuclide written report along with a positive upshot from a local injection is most helpful in establishing the diagnosis of a symptomatic pseudoarticulation. Meanwhile, selective radiculography serves as a reliable modality to diagnose far-out entrapment of the L5 nervus root. CT in combination with radiculography helps identify the point of impingement and the etiology of the L5 nerve root compression.^lxxx

The literature contains a total of 43 cases of surgical intervention for symptomatic LSTV. 27 patients were treated with resection, 8 underwent fusion, half dozen patients were treated for far-out syndrome, and the remaining 2 cases involved surgical intervention for extraforaminal nerve root impingement or pain contralateral to the LSTV.^{47, fifty–52, 63, 77–81} Only Santavirta et al. compared the surgically treated patients to a bourgeois treatment control group. The results of surgical handling were only slightly amend. The authors of these cases advocated for operative treatment of Bertolotti's syndrome in very select patients whose refractory hurting is definitively attributed to the transitional vertebrae.⁷⁸ Given the paucity of prove, further investigations with larger patient cohorts are needed to better understand the clan between the anomalous transverse process and low back pain that occurs with LSTV and to improve demonstrate the effectiveness of surgical intervention.⁶⁴

Disclosures

The authors declare no relevant financial disclosures.

• Copyright © 2015 ISASS - This manuscript is generously published free of charge by ISASS, the International Society for the Advancement of Spine Surgery

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