Measurement of interscalene space volume in diagnosis of thoracic outlet syndrome: a cadaver study

The aim of this study was to measure the volume of interscalene space in thoracic outlet region on cadavers and radiological images and to analyze the potential value of these measurements in diagnosis and treatment of thoracic outlet syndrome (TOS).

The dimensions of the anterior interscalene space in 8 formalin-fixed human cadavers were studied by direct measurement and additionally evaluation of the volume of this space were done by using mold and volume calculation formula of square pyramid, due to resembling a pyramid. In the second phase of this study, interscalene space volume was calculated by formula and compared to calculations from computed tomography (CT) sections in 18 TOS and 16 control patients.

There was a strong correlation between the volume calculated by formula (4.79 ± 2.18 cm3) and by mold (4.84 ± 1.58 cm3), (R = 0.934, p = 0.001) in cadavers. The average volume measured in TOS patients (2.05 ± 0.32 cm3) was significantly smaller than control patients (4.30 ± 1.85 cm3, p < 0.0001). There were excellent or good results in 14 patients whereas in 4 patients who had neurogenic TOS achieved fair results after surgery. In these 4 patients the average volumes of abnormal sides were close to the healthy sides.

In our study, volume of interscalene space in TOS patients was statistically smaller than control group. Also, the volume was even smaller in patients with excellent or good results after surgery. In this respect, volumetric measurements from CT sections could be used in diagnosis and treatment selection in TOS patients.