Human liver umbilical fissure variants: pons hepatis (ligamentum teres tunnel).

PURPOSE: In the classical description of normal liver anatomy, the umbilical fissure is a long, narrow groove that receives the ligamentum teres hepatis. The pons hepatis is an anatomic variant, where the umbilical fissure is converted into a tunnel by an overlying bridge of liver parenchyma. We carried out a study to evaluate the existing variations of the umbilical fissure in a Caribbean population. METHODS: We observed all consecutive autopsies performed at a facility in Jamaica and selected cadavers with a pons hepatis for detailed study. A pons hepatis was considered present when the umbilical fissure was covered by hepatic parenchyma. We recognized two variants: an open-type (incomplete) pons hepatis in which the umbilical fissure was incompletely covered by parenchyma ≤ 2 cm in length and a closed type (complete) pons hepatis in which the umbilical fissure was covered by a parenchymal bridge > 2 cm and thus converted into a tunnel. We measured the length (distance from transverse fissure to anterior margin of the parenchymatous bridge), width (extension across the umbilical fissure in a coronal plane) and thickness (distance from the visceral surface to the hepatic surface measured at the mid-point of the parenchymal bridge in a sagittal plane) of each pons hepatis. A systematic literature review was also performed to retrieve data from relevant studies. The raw data from these retrieved studies was used to calculate the global point prevalence of pons hepatis and compared the prevalence in our population. RESULTS: Of 66 autopsies observed, a pons hepatis was present in 27 (40.9%) cadavers. There were 15 complete variants, with a mean length of 34.66 mm, mean width of 16.98 mm and mean thickness of 10.98 mm. There were 12 incomplete variants, with a mean length of 17.02 mm, width of 17.03 mm and thickness of 9.56 mm. The global point prevalence of the pons hepatis (190/5515) was calculated to be or 3.45% of the global population. CONCLUSIONS: We have proposed a classification of the pons hepatis that is reproducible and clinically relevant. This allowed us to identify a high prevalence of pons hepatis (41%) in this Afro-Caribbean population that is significantly greater than the global prevalence (3.45%; P < 0.0001).

Biliary architecture of livers exhibiting right-sided ligamentum teres: an indication for preoperative cholangiography prior to major hepatectomy.

OBJECTIVE: To obtain information about the basic biliary anatomy of livers with right-sided ligamentum teres (RSLT). SUMMARY OF BACKGROUND DATA: RSLT is a relatively rare anomaly with a reported incidence of 0.2-1.2%. Although the portal/hepatic venous and arterial anatomy of livers with RSLT has already been established, the biliary architecture of such livers remains unclear. METHODS: RSLT was detected in 48 patients during 12,071 consecutive image readings (0.4%). Of these patients, the cholangiograms of 46 patients were analyzed, and their intrahepatic biliary tree confluence patterns were classified. RESULTS: The following four unique biliary confluence patterns were identified in livers with RSLT: the symmetrical type (23/46), independent right lateral type (13/46), total left type (6/46), and total right type (1/46). Analyses of the portal and arterial branching patterns of these livers showed that there were no correlations between their biliary confluence patterns and their portal or arterial ramification patterns. CONCLUSION: The basic biliary architecture of livers with RSLT was clarified. As the RSLT patients' anomalous biliary confluences differed from those seen in normal livers and were difficult to predict, preoperative cholangiography should be performed prior to complex hepatobiliary surgery involving livers with RSLT to ensure patient safety.

Successful Right Hemihepatectomy for a Patient with Right-Sided Round Ligament.

Right-sided round ligament (RSRL) is a rare congenital anomaly that is strongly associated with a number of intrahepatic vascular anomalies. Here, we report a 77-year-old male case of hepatolithiasis associated with RSRL for which resection was performed using right hemi-hepatectomy (RHH). Intraoperative ultrasonography revealed that the portal branch of segment 4 ramified from the right anterior portal branch, and the patient was diagnosed as having RSRL. To decide the resection line, the portal branch of segment 4 was punctured and stained with indigo carmine under ultrasonographic guidance, clearly demonstrating the demarcation line between the right and left hemiliver. RHH was then carried out successfully without injuring the portal branch of segment 4.

Absence of Ligamentum Teres in Developmental Dysplasia of the Hip.

BACKGROUND: Ligamentum teres is hypertrophied and should be resected in developmental dysplasia of the hip (DDH). We have observed a relatively high prevalence of absence of ligamentum teres (ALT) in severe DDH. The purpose of this study was to determine: (1) the percentage of ALT in DDH; (2) the risk factors correlating with ALT; and (3) the pathologic characteristics of DDH with ALT. METHODS: In 2012, 123 patients were hospitalized for open reduction of DDH. Clinical records were retrospectively reviewed. The distribution of ALT was discerned. The risk factors correlating with ALT were analyzed. The pathologic changes of the DDH with ALT were observed. RESULTS: For the 123 patients, there were 14 males and 109 females with a mean age of 2.2±1.7 years old. Forty-one cases were diagnosed with bilateral DDH, and 27 of them had open reduction for both hips. Thus, 150 hips were included. According to the Tonnis grading, there were 1 grade I, 43 II, 67 III, and 39 IV patients. During operation, the ligamentum teres was confirmed absent in 24 patients (28 hips, 18.67%), 22 of the hips with ALT was Tonnis grade IV (78.57%). It was present in the other 99 patients (122 hips). The difference of ALT among different grade (χ2=43.959, P=0.000) and different age (χ2=10.748, P=0.008) showed statistical significance, respectively. Logistic regression revealed only grading was the correlation factor of ALT (P=0.000). Pathologically, the femoral head was extremely small. The cartilage surface showed erosion-like change. The acetabulum was also diminutive but could match the femoral head well. CONCLUSIONS: At our institution, 18.67% of DDH needing open reduction was combined with ALT. The degree of dislocation was the only correlation factor of ALT. If the Tonnis grade was high, the hip was often associated with ALT. CLINICAL RELEVANCE: This study defines the prevalence of ALT and its risk factor in DDH, which will help to better understand the imaging, pathologic findings, and clinical outcome of DDH.