Control of fracture reduction robot using force/torque measurement.

We have developed a surgical robotic system for femoral fracture reduction employing indirect traction. Indirect traction in fracture reduction is a generally used surgical method for preventing complications such as bone splits caused by high stress on bones. For traction, a patient's foot is gripped by a jig and pulled to the distal side. Indirect traction has the advantage of distributing bone stress by utilizing a strong traction force; however, this procedure does not accurately control the proper positioning of fractured fragments when a surgical robot is used. The human leg has knee and an ankle joints, and thus robotic motion presents problems in not being able to directly propagate reduction motion to a fractured femoral fragment, rendering control of bone position difficult. We propose a control method for fracture reduction robots using external force/torque measurements of the human leg to achieve precise fracture reduction. Results showed that the proposed method reduced repositioning error from 6.8 mm and 15.9 degrees to 0.7 mm and 5.3 degrees, respectively.

[Hepatic arteriography under temporary hepatic venous occlusion].

Hepatic arteriography with and without temporary segmental hepatic vein occlusion was performed in 10 patients, five of whom had chronic liver injury. Hepatic arteriograms obtained during hepatic venous obstruction demonstrated significantly more peripheral and definite arterial branches in the occluded area and fewer peripheral branches in the non-occluded segment. A prolonged, dense hepatogram (sinusoidogram) showing hepatofugal opacification of the portal vein was obtained in the occluded area. Only one case with a large veno-venous anastomosis did not show these findings. Hepatic arteriograms in two cases with hepatocellular carcinoma provided clear visualization of peripheral portal branches that could act as efferent tumor vessels during regional temporary hepatic vein occlusion. Temporary hepatic venous occlusion may cause a sudden increase of hepatic arterial flow in the occluded area and transsinusoidal arterioportal communication there. This method can be useful for the diagnosis and arterial infusion or embolization therapy of hepatic diseases.

[CT findings complicating percutaneous nephrostomy, lithotomy and lithotripsy].

Reviews of the CT scans of percutaneous nephrostomy, lithotomy and lithotripsy disclosed 14 out of 78 cases (17.9%) with evidence of complications. Renal and perirenal hematomas were detected in five cases and the other five cases showed collections of contrast material in the retroperitoneum except for the anterior pararenal space. CT demonstrated clearly the anatomic distribution and extent of renal hemorrhage and extravasation of contrast material. Three cases of pleural effusion on CT were accompanied by blood or contrast material collections in the posterior pararenal space. No patients required immediate surgery and CT findings helped the choice of conservative therapies.

[A case of giant cavernous hemangioma with hemoperitoneum due to blunt abdominal trauma; CT findings].

A 55-year-old woman with a giant cavernous hemangioma in the liver with hemoperitoneum due to blunt abdominal trauma was reported. CT findings of the liver at first thought to be hepatic injuries. But serial studies revealed that the CT findings were dependent on giant cavernous hemangioma and apart from hepatic injury.