# Diagnostic Limitations and Aspects of the Lumbosacral Transitional Vertebrae (LSTV)
## 1 Introduction
LSTVs pose a diagnostic dilemma for the treating physician, as they may remain undetected on plain radiographs and even on advanced imaging; moreover, even if the malformation is recognized, patients with the LSTV may be asymptomatic or have nonspecific symptoms, such as low-back pain with or without radicular symptoms. Special attention should be given to younger patients under 30 years of age with chronic lumbar symptoms. Here, diagnostic exclusion or confirmation of the LSTV is required [21]. In humbalgia, differences in muscle mass distribution are also associated with lordosis of the lumbar spine [22]. The LSTV are associated with a reduction in muscle volume and an increase in muscle degeneration of both the lumbar and trunk muscles compared to healthy individuals [23]. A differential relationship between lumbalgia and the type of the LSTV can be established. However, the segment affected by the LSTV must be distinguished from the adjacent segment as the cause of the symptoms [24]. Unilateral LSTV result in asymmetric biomechanical stresses. The side with the extra L5/S1 joint bears a greater proportion of the load, resulting in lateral tilt with scoliotic curvature. This local loading leads to greater wear and unilateral muscle activity. In addition, asymmetric motion may also affect disc degeneration [25]. The LSTV may also be associated with spina bifida occult as another pathological change [26; 27]. The topic of scoliosis is addressed in 16 papers. In a study in the Turkish Army, the LSTV were diagnosed in 12.9% of 3132 men [28]. Another regional assignment of prevalence to the southern European population is reported by [PERSON] et al. with 24.9% for the group LSTV Castellvi type II, III and IV [29]. In the work of [PERSON] et al., a prevalence of LSTV in 198 patients with scoliosis is found in 18.2% [30]. The change in segmental mobility is measured in a paper by [PERSON] et al. and summarized as follows: Patients with the LSTV show reduced range of motion in the transitional segment and a significantly increased distribution of motion to the cranially adjacent segment on flexion-extension radiographs. The increased proportion of mobility in the cranial adjacent segment may explain the higher rates of degeneration within the segment [31]. The influence of the LSTV on pelvic alignment with acetabular orientation is also described by the same group [32]. The impact of the LSTV on surgical interventions is also scientifically discussed but is not the focus of this article. An improvement of the patients' quality of life is describedby surgical interventions. This concerns both the lysis of LSTV and the fusion of the segment depending on the degenerative changes [33]. However, surgical problems due to the altered anatomy, especially of the ventral vascular plant, must also be considered in surgical planning [34]. The LSTV have a wide range in diagnosis, especially in type I, which is reflected in the widely scattered prevalence data. The biomechanical limitations and the possible causes of the symptoms are not yet sufficiently differentiated. In particular, there is little information about the intervertebral disc in the LSTV. The aim of this paper is to investigate the diagnosis of the LSTV in relation to LBP. The prevalence of the LSTV in the literature and in our own work should be documented with respect to the problem of diagnosis of LSTV, especially of Castellvi type I.