C. Shwaartz1, R. S. Lingnurkar2, B. Cohen1, M. Cohen1, H. K. Rosenberg1, C. M. Divino1 1Icahn School Of Medecine At Mount Sinai,General Surgery,New York, NY, USA 2Central Michigan University College Of Medicine,College Of Medicine,Mount Pleasant, MI, USA
Introduction:
In recent years, ultrasonography has gained popularity as an adjunct to physical examination, replacing the now abandoned contrast herniography to detect occult inguinal hernias. Despite pronounced heterogeneity in reported positive and negative predictive values for this modality, the integration of ultrasound in the diagnostic algorithm for inguinal discomfort has been advocated when physical examination alone is inconclusive. The aim of this study is to confirm this recommendation by assessing the diagnostic value of ultrasonography in detecting occult inguinal hernia, and appraise the limits of its detection rate across discrete populations.
Methods:
We retrospectively reviewed the demography and the outcome of 137 patients presenting with inguinal discomfort between the years 2013 and 2016 in a single surgeon practice. Inclusion criteria were the following: (1) inconclusive physical examination by a single surgeon, and (2) ultrasound and interpretation by a single radiologist following physical examination. Follow up data were collected by either a clinic visit for inguinal hernia repair soon after inguinal ultrasound, or a telephone survey querying for both inguinal hernia repair during the follow up period, and eventual resolution of symptoms. Demographic factors affecting the accuracy of ultrasonography were analyzed.
Results:
137 patients were included in the study, with a median age of 49 years, of which 45% were females. 26 (19%) were tested positive and 111 (81%) were tested negative for occult inguinal hernia. A total of 18 (13%) patients underwent surgery soon after inguinal ultrasound. Of the remaining 119 patients, 101 (85%) were successfully called for follow up. 37 (31%) patients remained symptomatic on follow up, and 4 (3%) patients had undergone inguinal hernia repair during the follow up period. Positive and negative predictive values (PPV and NPV) for ultrasound in detecting occult inguinal hernia were determined to be 79.17%, and 61.05% respectively. Variance across cohort was noted: ultrasound accuracy was influenced by gender (PPV 90.91% in females vs. 69.2 in males), age (PPV 90.91% below 49 and 71.4 above 49), BMI, prior hernia surgery and comorbidities predisposing to hernia formation (lung disease, constipation, prostatism) (PPV of 85.7% with comorbidity vs. 76.4% without).
Conclusion:
Inguinal ultrasonography has a moderately high positive predictive value, but a relatively low negative predictive value for detecting occult inguinal hernia. Our study uniquely stratified these diagnostic values across discrete populations, revealing particularly high positive predictive values for females, patients aged ≤ 49, and patients with predisposing comorbidities. These findings suggest that ultrasound may be most effective in detecting occult inguinal hernia in representative patients.