Laparoscopic abdominal perineal rectal resection for rectal cancer with a horseshoe kidney using preoperative 3D-CT angiography: a case report

Background A horseshoe kidney is a congenital malformation involving the fusion of the bilateral kidneys and is often accompanied by anomalies of the ureteropelvic and vascular systems. When performing resection of colorectal cancer in a patient with horseshoe kidney, damage to the ureter or excessive renal arteries should be avoided. To achieve this purpose, comprehensive preoperative anatomical assessments and surgical planning are important. Here, we report a case of a laparoscopic abdominal perineal rectal resection for lower rectal cancer with a horseshoe kidney. Case presentation A 79-year-old woman presented with bloody stool and was diagnosed with advanced lower rectal cancer, immediately above the rectal dentate line, without metastasis. A preoperative computed tomography (CT) scan revealed a horseshoe kidney, while a three-dimensional CT (3D-CT) angiography revealed aberrant excess renal artery from the aorta to the renal isthmus. The left ureter ran in front of the isthmus of the horseshoe kidney and presented calculus formation. Laparoscopic abdominal perineal rectal resection was performed with D3 lymph node dissection. During the operation, we mobilized the sigmoid colon mesentery via a medial approach and preserved the left ureter, the left gonadal vessels, and the hypogastric nerve plexus in the retroperitoneum in front of the horseshoe kidney. Conclusions We report a rare case of rectal cancer surgery in a patient with a horseshoe kidney. We discuss the anatomical peculiarities of a horseshoe kidney, such as excess renal arteries, inferior vena cava, ureter, gonadal vessels, and nerves, that should be preserved according to the literature. We suggest that preoperative 3D-CT angiography is both useful for revealing the relationship between the vascular system and a horseshoe kidney and helpful when performing laparoscopic surgery for a left-sided colon and rectal cancer to avoid intraoperative injury.

Computational Fluid Dynamics for Cerebral Aneurysms in Clinical Settings

Hemodynamics is thought to play an important role in the pathogenesis of cerebral aneurysms and recent development of computer technology makes it possible to simulate blood flow using high-resolution 3D images within several hours. A lot of studies of computational fluid dynamics (CFD) for cerebral aneurysms were reported; therefore, application of CFD for cerebral aneurysms in clinical settings is reviewed in this article.CFD for cerebral aneurysms using a patient-specific geometry model was first reported in 2003 and it has been revealing that hemodynamics brings a certain contribution to understanding aneurysm pathology, including initiation, growth and rupture. Based on the knowledge of the state-of-the-art techniques, this review treats the decision-making process for using CFD in several clinical settings. We introduce our CFD procedure using digital imaging and communication in medicine (DICOM) datasets of 3D CT angiography or 3D rotational angiography. In addition, we review rupture status, hyperplastic remodeling of aneurysm wall, and recurrence of coiled aneurysms using the hemodynamic parameters such as wall shear stress (WSS), oscillatory shear index (OSI), aneurysmal inflow rate coefficient (AIRC), and residual flow volume (RFV).

A case of laparoscopic anterior resection for rectal cancer with duplication of the inferior vena cava using preoperative 3D computed tomography angiography

We report the case of a patient with duplication of the inferior vena cava (DIVC) who underwent anterior laparoscopic resection for rectal cancer. A 66-year-old woman presented with abnormal lung shadows on a chest x-ray during a routine health checkup. She was diagnosed with rectal cancer and lung metastasis using colonoscopy and thoracoabdominal computed tomography (CT). In addition, a 3D CT angiography revealed double inferior vena cava, one on either side of the aorta. The preoperative diagnosis was rectal cancer cT3N0M1a(Lung) cStage IVA with DIVC, and a two-stage surgery was planned. The first stage was high anterior laparoscopic resection. This was safely performed because the pre-hypogastric nerve fascia was preserved and the left inferior vena cava was not visualized during the surgery. During the second stage of the surgery, video-assisted thoracoscopic left lower lobectomy was performed and no recurrence was observed for >6 months after the second surgery.

Hemodynamic features of offending vessels at neurovascular contact in patients with trigeminal neuralgia and hemifacial spasm

OBJECTIVEOffending vessels at the site of neurovascular contact (NVC) in patients with trigeminal neuralgia (TN) and hemifacial spasm (HFS) may have specific hemodynamic features. The purpose of this study was to investigate the wall shear stress (WSS) of offending vessels at NVCs by conducting a computational fluid dynamics (CFD) analysis.METHODSThe authors retrospectively analyzed the cases of 20 patients (10 with TN and 10 with HFS) evaluated by 3D CT angiography and used the imaging findings for analysis of the hemodynamic parameters. The 3D CFD images were directly compared with the NVCs determined by simulated multifusion images of CT angiogram and MR cisternogram, and operative photos. The magnitudes of the WSS (WSSm) at the proximal (WSSm-p), just-beginning (WSSm-j), contact site (WSSm-s), and distal (WSSm-d) areas of each NVC were analyzed. The ratios of the WSSm-j, WSSm-s, and WSSm-d areas to the WSSm-p area were calculated individually. The direction of the WSS (WSSv) and its temporal variation (WSSvV) were depicted and morphologically compared with the NVC confirmed by simulated images and operative findings.RESULTSThe ratios of WSSm at the just-beginning and the contact site to the proximal area of the NVCs (WSSm-j/WSSm-p and WSSm-s/WSSm-p) were both significantly higher than that at the distal area (WSSm-d/WSSm-p) (p < 0.05). The WSSv and WSSvV at the NVCs showed small variation in a single cardiac cycle, especially along the areas that were in contact with the affected nerve.CONCLUSIONSAreas of relatively high WSSm and temporal variation of WSSm (WSSmV) were observed at the NVCs. Less mobility of the WSSv and WSSvV was detected along the side of the vessels in contact with the nerves. These findings may be consistent with the actual area of the NVC. Hemodynamic features of the site of NVC can be added to the preoperative simulation for MVD surgery, which may be useful for the diagnosis and treatment planning of TN and HFS.