Bone single-photon emission computed tomography and three-dimensional computed tomography in the diagnosis of low costal variation and pathologies.

In general, there are five lumbar vertebras in normal human subjects. But occasionally there are six. In such a situation, a radiologist need to discern between lumbarization of S1 (S1 vertebra becomes segmented and mimics L5) or due to hypoplastic 12(th) ribs, hence the T12 vertebra is wrongly assumed to be L1. These interesting images serve a multimodality approach to right aplasia/left hypoplasia of 12(th) rib, injury of left 11(th) rib and subluxation of left 11(th) Costovertebral joint in a patient with lumbar back pain.

A 37-year-old woman with left low back pain for 3 mount durations was admitted to the department of orthopedic surgery and traumatology. Patient was not described any major trauma. Her laboratory finding was compatible with iron deficiency anemia. Other serologic and hematologic results are within normal limits. On anteroposterior and lateral radiography at first glance, there was six lumbar vertebra [Figure 1a]. This distinction matters little to the health of the patient him/herself but can have a terrible effect if the surgeon decides to operate on him/her and there is a misconception of the level.[123] There are typically no anatomic complications using the anterior approach from beneath the costal margin. The posterior approach requires an incision at the level of the spinous process of the first lumbar vertebra to avoid entering the pleura.[456] On the thoracolumbar computed tomography (CT), there was only five lumbar vertebra and right 12th rib aplasia and left 12th rib hypoplasia [Figure 1b]. But there was no pathological finding to explain the pain.

Figure 1

(a) At first glance, there were six lumbar vertebrae on the anteroposterior radiography (b) There were only five lumbar vertebrae and right 12th rib aplasia and left 12th rib hypoplasia (arrow) on the thoracolumbar computed tomography

The patient with intense low back pain was also further investigated with three phase bone scintigraphy (TPBS), whole body bone scintigraphy (WBBS) and thoracolumbar bone single-photon emission computed tomography (SPECT). There were no abnormal findings on the first two phase of TPBS. On the WBBS, there were not seen the ribs of 12th and moderate diffuse activity involvement was observed on the left 11th rib [Figure 2a]. In the coronal SPECT images, there was diffuse increased uptake in the left 11th rib [Figure 2b]. On the three-dimensional-CT imaging, left 12th hypoplastic rib was observed while right one was not. Also left 11th Costovertebral joint was subluxated [Figure 3]. Ribs 11 and 12 do not attach to an anterior costal cartilage or transverse process, but rather invest into the fascia and musculature of the lateral and posterior abdominal wall. Ribs 11 and 12 are described as having caliper motion, primarily influenced by their relationship to their muscular attachments. The caliper motion of ribs eleven and twelve can be seen to be related to the near-vertical orientation of the small transverse processes of T11 and T12 as well as the way the ribs invest into the abdominal musculature, thoracolumbar fascia, and diaphragm. Another important lower extremity muscle affecting rib cage motion is the quadrates lumborum, which originates from the iliolumbar ligament and the posterior part of the iliac crest, runs along the posterior lateral aspect of the vertebral column, and inserts on the transverse processes of the upper four lumbar vertebra and the inferior aspect of the 12th rib on each side.[7] According to all of these findings, repetitive daily minor posttraumatic subluxation of the left 11th rib and injury was diagnosed in this patient.

Figure 2

(a) There were not seen the ribs of 12th and moderate diffuse activity involvement was observed on the left 11th rib on the whole body bone scintigraphy (b) There was diffuse increased uptake in the left 11th rib (arrow) on the coronal single-photon emission computed tomography images

Figure 3

On the three-dimensional computed tomography imaging, left 12th hypoplastic rib (arrow) was observed while right one was not. Also left 11th costovertebral joint was subluxated