LUMBOSACRAL TRANSITIONAL VERTEBRAE IN PATIENTS ATTENDING A TERTIARY CARE HOSPITAL OF NEPAL

1* 2 Sanzida Khatun , Diwakar Kumar Shah Khatun S et al Received : 18 May, 2021 Accepted : 21 July, 2021 Published : 04 November 2021 ISSN: 2542-2758 (Print) 2542-2804 (Online) 1507 Birat Journal of Health Sciences Vol.6/No.2/Issue 15/May-Aug., 2021 Original Research Ar cle


INTRODUCTION
Lumbosacral Transi onal vertebrae (LSTV) are congenital anomalies of lumbosacral vertebral junc on. It may present either as sacraliza on of fi h lumbar vertebrae (L5) or lumbariza on of first sacral vertebrae (S1). Sacraliza on of L5 vertebra involves broadened and elongated transverse process of L5 to its par al or complete fusion with the sacrum. Lumbariza on of S1 involves par al or complete separa on 1 of S1 vertebra from remaining of the sacrum. The iden fica on of LSTV can be done on all imaging modali es, but they are supposedly best imaged on Ferguson 2 radiographs (AP radiographs angled cranially at 30°). The vertebral column supports the weight of the upper part of human body. There is axial transmission of increased magnitude of ver cal compressive forces to lumbosacral joint; the force is extended to lower limbs through sacrum 3 and its ligaments. But when anomaly of L5-S1 region occurs, the iliolumbar ligaments are the sole mechanism 4 resis ng the load. Thus, various secondary pathological spinal condi ons such as intervertebral disc hernia on and/or degenera on, facet joint arthrosis and spinal canal or foraminal stenosis are associated with the presence of 5 LSTV. The failure in the iden fica on may lead to clinical consequences such as errors in diagnosis of disease and 2 lumbosacral procedures. Knowledge regarding varia on in anatomy of lumbosacral vertebrae and its pathology is important in reaching a diagnosis, planning treatment and improving prognosis of various lumbosacral condi ons and diseases. There are very few studies done to es mate the occurrence rate of LSTV in Nepal. This study shall add to the knowledge of prevalence and pa erns of LSTV in popula on of eastern region of Nepal as pa ents from number of places from eastern region of Nepal present to this Hospital. The aim of this study was to determine the prevalence and pa erns of LSTV in pa ents presen ng to Department of Radiology of Nobel Medical College Teaching Hospital, Nepal.

METHODOLOGY
A descrip ve cross-sec onal study was conducted in Department of Radiology of Nobel Medical College Teaching Hospital, Nepal. The study period was from May 1, 2020 to April 30, 2021. The ethical approval was taken from IRC-NMCTH of the ins tu on. The informed consent was signed by the par cipants. Plain radiographs including Antero-posterior (AP) and Lateral views of lumbosacral spine of pa ents referred for the scan for various reasons such as low back pain, injury, monitoring diseases such as osteoporosis and osteoarthri s were analyzed. The pa ents of all age groups were included in the study. The pa ents who had deformity or spinal surgery of lumbosacral area and radiographs with poor image quality were excluded from the study. The study was done in 343 subjects. Simple random sampling was done. th In the plain radiographs of lumbosacral spine, the 12 thoracic vertebrae (T12) where the ribs were a ached were iden fied. The vertebra immediately below this vertebra was designated as first lumbar vertebra (L1). The presence or absence of LSTV was noted by coun ng down ll L5-S1 region craniocaudally. Among the ones which had presence of LSTV, the pa ern was further classified based on Castellvi 7 classifica on as follows. Type I: Dysplas c and enlarged transverse process measuring ≥19mm: A, unilateral; B, bilateral. Type II: Enlarged transverse process with pseudoar cula on with sacrum: A, unilateral; B, bilateral. Type III: Complete fusion of transverse process with sacrum: A, unilateral; B, bilateral. Type IV: Mixed type with type II on one side and Type III on other side. The data was entered and analyzed using Sta s cal Package for Social Sciences 16.0 so ware. The frequencies, percentages, mean and standard devia on was derived by descrip ve analysis.

RESULT
In this study, the radiographs of 343 pa ents were observed. There were 117 (34.1%) male and 226 (65.9%) female pa ents. The age of the pa ents ranged from 6 years to 86 years with a mean of 47±16 years. Out of 343 pa ents, LSTV was found in 61 (17.8%) subjects. The prevalence of LSTV didn't vary much in males and females; LSTV was found in 22 (18.8%) of total (117) males and 39 (17.2%) of total (226) females. Thirty-eight subjects (11.1%) exhibited sacraliza on and 23 (6.7%) showed lumbariza on. Among the male pa ents, 19 (16.2%) had sacraliza on, whereas, 3 (2.6%) had lumbariza on. However, among the female pa ents, lumbariza on was seen in 20 (8.8%) subjects which was more common than in males and sacraliza on was present in 19 (8.4%) subjects. According to Castellvi classifica on, among the 61 subjects with LSTV, type I was the most common type of LSTV which was present in 29 (47.5%) par cipants. Type II and type III was equally frequent and type IV was the least frequently occurring type. Out of most commonly occurring type I LSTV, type I A (unilateral type I LSTV) was present in 8 (13.1%) and type I B (bilateral type I LSTV) was present in 21 (34.4%)of total LSTV subjects. Type II A was found in 10 (16.4%) , type II B in 5 (8.2%) , type III A in 6 (9.8%) , type III B in 9 (14.8%) and type IV in 2 (3.3%) of total LSTV subjects. Table 2 displays genderwise distribu on of different types of LSTV according to Castellvi classifica on. Both in males and females, the most common type of LSTV was type I. In both the genders, type I B was more common that type I A. Type IV LSTV was least frequent among females and absent in males. Table 3 displays distribu on of different types of LSTV in sacraliza on and lumbariza on. Among the sacralized LSTV, type I was found in 15 (39.5%) subjects which was the most prevalent type and type IV was found in only 1 (2.6%) subject. Similarly, among the lumbarized LSTV, type I was found in 14 (60.9%) subjects all of which represented bilateral type (type I B) and type IV was least prevalent which was found only in 1 (4.3%) subject. Pearson's chi-square test was done to see the rela on between types of LSTV and sacraliza on or lumbariza on in which sta s cally significant difference was observed (p value = 0.013).

DISCUSSION
Varia ons in the lumbosacral region of the spine are fairly common. LSTV is a commonly encountered anomaly in lumbosacral region. The present study reports the prevalence of LSTV and its pa ern in popula on of eastern Nepal. In this study, LSTV was found in almost one-fi h of the subjects. Sacraliza on was more common than lumbariza on. In females, however, the frequency of sacraliza on and lumbariza on was almost equal. It has been documented that the prevalence of LSTV varies worldwide. In this study, LSTV was found in 61 (17.8%) subjects out of 343 pa ents. Similar to this finding, the prevalence of LSTV in various studies has been reported to 1,6,[8][9][10][11][12][13][14][15][16][17] be about 10% to 20%.
In contrast to these findings, higher prevalence of LSTV ranging from 23% to 36% have been reported by Lee  In few studies, however, lower frequency of sacraliza on in 11,14,24 comparison with lumbariza on has been demonstrated. Paik et al reported equal prevalences of 5.3% each of 15 sacraliza on and lumbariza on in their study. When classified according to Castellvi classifica on, the most common type of LSTV observed was Type I. Bilateral type I (type I B) LSTV was more common than unilateral type I (type I A) LSTV. The finding in this study that type I LSTV is most prevalent is consistent with the findings of most of the 6,23,26 authors.
However, the data differs from the findings of Bha arai and Apazidis which showed more frequent type I 6,23 A than type I B. Khashoggi et al demonstrated that type I B LSTVwas more common than type I A LSTV which is similar 26 to the finding of this study. The presence of anomaly in this region may be related to occurrence of various pathological and clinical condi ons 3,5 as this is a significant load bearing area of the body. They are usually the result of altered morphology of joints and 28 facets. The associa on of LSTV and lower back pain has 2,5,16,19,28,29 been well documented in various studies.
Castellvi type II and IV type of LSTV, par cularly, have been frequently associated with lower back pain resul ng due to 16,29 pseudoar cula on suscep ble to osteophytes forma on. More degenera ve lumbar disc above LSTV than between LSTV and sacrum in findings in MRI have been documented 5,30 in various studies. Spinal surgeries at incorrect levels have been reported in LSTV due to errors in numeric iden fica on of the vertebrae. This may result in second surgery which may be detrimental to the pa ent and hospital in terms of cost, disease and post-opera ve complica ons. It is impera ve that the spinal surgeons suggest review of plain radiographs along with the MRI to be aware of LSTV to reduce surgical and 2,23 procedural errors. Furthermore, a study demonstrated that the presence of LSTV limits the clinical improvement 31 a er microdisectomy for lumbar disc hernia on. The pa ent and the clinician should also be prepared for clinical discrepancies in cases of anomaly.

LIMITATIONS OF THE STUDY
This study doesn't represent the prevalence of larger popula on as it was a hospital based study. Furthermore, the imaging of the pa ents presen ng to hospital for some underlying factor were analysed which doesn't represent the en re healthy and asymptoma c popula on. Error might have occurred due to presence of extra lumbar rib. The presence of extra lumbar rib could not be confirmed as chest radiograph of same pa ent was not assessed.

RECOMMENDATIONS
Addi onal research with mul ple ins tu on based studies including healthy control group will be required to assess occurrence of LSTV and its associa on with various clinical condi ons. The radiographs of complete trunk of the same par cipant should be assessed to accurately count the vertebrae and the ribs. Mul ple observers to minimize the diagnos c error can be implemented.

CONCLUSION
The LSTV is prevalent in almost one-fi h of subjects presen ng to department of radiology of Nobel Medical College and Teaching Hospital, Biratnagar for lumbosacral scan. Sacraliza on occurs more frequently than lumbariza on, both of which alter the morphology of anatomical structures in spine. The presence of anomaly in this region may be related to occurrence of various pathological and clinical condi ons. It is impera ve that the spinal surgeons and clinicians review plain radiographs along with the MRI to be aware of LSTV to reduce surgical and procedural errors.