INCIDENCE OF LOW BACKACHE IN RELATION TO ANATOMICAL VARIATIONS OF SACRAL HIATUS

Abstract

Lumbago is pain in the area amid the costal margin and inferior gluteal folds. Globally it is the fourth ‘most common cause’ of disability associated years. Heavy weight lifting, twisting, bending, high BMI and sacral developmental defects have been associated with high frequency of low backache. The sacral hiatus is an arched gap on the dorsal surface of the sacrum. It is a continuation of the sacral canal that contains the sacral nerve, coccygeal nerve, fibrous tissue, fatty tissue and filum terminale. Variations of the sacral hiatus are related to increase in risk of iatrogenic problems in caudal procedures as well as mechanical low back pain. The study was conducted to compare the shape, level of apex, level of base, length, anteroposterior, and transverse diameters of hiatus sacralis between cases with low backache and control subjects, compare the incidence of variations of sacral hiatus between males and female cases, compare the demographics and patient characteristics between cases and controls, compare the hiatal variations, demographics and patient characteristics within cases, and determine the relationship of the anatomical variations, demographics and patient characteristics with low back pain. The study was conducted at PNS Shifa hospital and Advanced Radiology Clinic, Karachi after the approval of synopsis (Appendix A) and ethical approval from BUMDC and Advanced Radiology Clinic (Appendix B). Eighty nine cases and eighty nine controls were enrolled by non-probability convenient sampling. The cases were recruited from outpatient departments of rehabilitation medicine, orthopedic surgery and emergency medicine based on presenting complaints and examination while controls were asymptomatic patients presenting to the radiology department from other specialties for the purpose of medical review. Individuals meeting the inclusion criteria after signed informed consent (Appendix C) were included in the research project. Anteroposterior and lateral radiographic images of the lumbosacral spine were obtained through the Toshiba Rotanode X-Ray machine. Using the anteroposterior radiographs, the hiatus was identified inferior to the median sacral crest. The shape, level of apex and level of base were identified on observation. The length was measured from the hiatal apex to a point at the center of its base. The anteroposterior diameter was measured at the apex of the hiatus in the lateral view and the width was measured between the sacral cornua. The participants’ height and weight were measured xiv using the stadiometer. Information regarding demographics and factors related to low back pain were recorded in the subject evaluation proforma (Appendix D). A total of 179 participants were evaluated. High possibility of “low back pain” was found with hiatal shapes inverted ‘U’ and ‘M’, hiatal apex at S1 or S2, base at S3, hiatal length (more than 30mm), transverse width (more than 13mm) and variations in the anteroposterior diameter. Predominance of back pain was observed in married individuals. Prevalence of symptoms was high among cases with no exercise. High incidence was observed among house wives, office workers, and field workers. House work, prolonged standing and bending were most common aggravators of back pain. Association between increased BMI and weight with occurrence of low back pain was established. The current study concluded that there is an association between the variations of hiatal anatomy and low back pain. Possibility of low back pain is present in hiatal shapes inverted ‘U’ and ‘M’, apex above S3, base at S3 or above, long, deep and wide hiatus. A high BMI, sedentary lifestyle, occupation and physical workload are also significantly related to low back pain.