Association of Kyphosis and Spinal Skeletal Abnormalities with Intrathoracic Stomach: A Link Toward Understanding its Pathogenesis

Background: Modern-day concepts about the pathogenesis of an intrathoracic stomach include crural diaphragm muscular deterioration, loss of phrenoesophageal ligament integrity, and presence of abdominothoracic pressure gradients. The role of spinal abnormalities has received little attention. Based on clinical observation, we hypothesized that kyphosis and other spinal diseases are components of the pathophysiology of an intrathoracic stomach. Study Design: The study population consisted of 98 patients (men, n = 22; women, n = 76; mean age 69.4 years) undergoing operations for type III or IV hiatal hernia with an intrathoracic stomach. Twenty-four age- and gender-matched control patients without hiatal hernia undergoing pulmonary or pleural procedures were used for comparison. Chest radiographs were assessed for spinal abnormalities, including degree of kyphosis, measured from superior T4 to inferior T12 (modified Cobb method), spinal fractures, osteoporosis, and scoliosis. Statistical analyses included two-sample t-test and Fisher's exact test. Results: Patients with intrathoracic stomach had a greater degree of kyphosis than control patients (Cobb angle, 50.2 degrees versus 39.7 degrees; p < 0.001). This difference was most pronounced in women (Cobb angle, 51.7 degrees versus 40.4 degrees; p < 0.001), although the difference in men was not significant (Cobb angle, 45.0 degrees versus 38.1 degrees; p = 0.25). Patients with an intrathoracic stomach had significantly more vertebral fractures (37 of 98 [38%] versus 3 of 24 [13%]; p < 0.05). There was no difference in prevalence of degenerative changes (51 of 98 [52%], versus 13 of 24 [54%]), osteopenia (30 of 98 [31%] versus 6 of 24 [25%]), and scoliosis (27 of 98 [28%] versus 6 of 24 [25%]). Conclusion: Patients with an intrathoracic stomach have a higher degree of kyphosis and more vertebral fractures than age- and gender-matched controls. These data suggest that change in spinal curvature can be important in the pathogenesis of the intrathoracic stomach, a growing problem of our aging population.