[Automatic registration of patients with A-mode ultrasound for computer-assisted surgery. Laboratory proof of concept]

BACKGROUND

The main source of error in 3D navigation is the patient-to-image registration process. Anatomical landmarks or adhesive markers perform sub-optimally. Bone-anchored invasive markers significantly change the clinical workflow of navigated ENT surgery, are invasive and cause patient discomfort. In order to minimize registration errors and to further streamline the clinical use of intraoperative 3D navigation we demonstrate that A-mode ultrasound allows an accurate 3D surface profile of the os occipitale to be created which can be reliably registered on preoperative patient CT data.

METHODS

The transducer is mechanically positioned with sub-millimeter accuracy on the patient's occiput. From the sound echos a 3D surface is generated and registered to the preoperative CT images with the iterative closest point (ICP) algorithm. The evaluation of our setup was performed on three anatomic specimens and one bony skull.

RESULTS

The ultrasound echoes from the occiput allowed the creation of an adequate 3D surface which could be registered to a segmentation of the CT image with an accuracy greater than 1.5 mm. The experiments were evaluated by an intuitive representation of the spatial deviation between CT and ultrasound data as a color-coded map.

CONCLUSION

The approach to scan the posterior skull with A-mode ultrasound enables automatic intraoperative registration and can be integrated into the intraoperative setup.

Comparison of the analgesic effect of betamethasone and diclofenac potassium in the management of postoperative haemorrhoidectomy pain

BACKGROUND

Outpatient postoperative haemorrhoidectomy pain remains a difficult problem. The purpose of this study is to compare the results of the use of betamethasone with diclofenac potassium in postoperative pain following haemorrhoidectomy.

MATERIAL AND METHODS

Closed haemorrhoidectomy was performed on 40 patients who were diagnosed grade III, grade IV haemorrhoid on physical examination. Patients were divided equally randomized into two groups, prospectively (betamethasone was used for 20 patients and diclofenac potassium was given for 20 patients). A verbal categorical scale was used to evaluate postoperative pain (for pain intensity, none=0, mild=1, moderate=2 and severe=3).

RESULTS

The amount of narcotics required on postoperative first, second and third day were significantly less in the betamethasone group than in the diclofenac potassium group (P < 0.001) (Pearson Chi-Square test).

CONCLUSION

Results indicate that use of betamethasone provides more effective analgesia than diclofenac potassium for postoperative pain management in the haemorrhoidectomy patient.

Prophylactic appendectomy: is it worth to be done?

There are still many controversial issues in prophylactic appendectomy. In this retrospective study, we have appraised the reasons and results of prophylactic appendectomies performed between January 1997 and August 1999. Sixty four prophylactic appendectomy cases were included in this study and all resected specimens were submitted to histopathological analysis. In 23 patients with incisional hernias, a prophylactic appendectomy was performed as, in the future, dense adhesions may lead to difficult appendectomy. Additional appendectomy had no negative effect on perioperative complications, compared with the patients without appendectomies. In conclusion, in the presence of optimal conditions, prophylactic appendectomy can be performed safely.

The effect of lymphatic blockage on the amount of endotoxin in portal circulation, nitric oxide synthesis, and the liver in dogs with peritonitis

This study was performed to investigate the effect of lymphatic blockage on the amount of endotoxin in portal venous blood, nitric oxide synthesis, the release of aspartate aminotransferase (AST) from the liver, hepatic damage, and survival in an experimental model of dogs with peritonitis. The dogs were divided into a control group (group 1), an unligated thoracic duct peritonitis group (group 2), and a ligated thoracic duct peritonitis group (group 3). Peritoneal fluid and blood from the portal vein and femoral artery were taken for peritoneal culture, endotoxin, and AST assay, respectively, and liver biopsies were performed to assess for hepatic damage and for nitric oxide assay. There was a higher bacteria count in the peritoneal fluid from group 3 than in that from group 2 (P < 0.0001). Bacteria grew in all of the blood cultures from the group 2 animals, but growth was seen only in blood cultures from four of the group 3 animals. The levels of endotoxin, nitrite, and AST levels in group 3 were significantly increased in comparison with those in group 2 (P < 0.0001). Extensive hepatocellular necrosis with hemorrhage was observed in the livers of the group 3 animals, and all of them died within 48 h. The results of this study suggest that the blockage of lymph flow has a negative effect on liver and survival in dogs with peritonitis, and that hepatic damage is directly related to the amount of endotoxin to which the liver is exposed.

Use of an autologous vein graft and stent in the repair of common bile defects: an experimental study

We investigated the effectiveness of using an autologous vein graft and stent in the repair of large defects of the common bile duct (CBD) in a canine model. A 3-cm segment of the vena cephalica antibrachii and a 2-cm segment of the CBD were removed from eight healthy mongrel dogs with normal blood biochemistry levels. A stent was passed through the vein segment, and one end was introduced into the proximal end of the CBD while the other end was introduced into the distal end. The venous graft was then sutured to the CBD. A liver biopsy was taken for histopathological examination during laparotomy and relaparotomy. Blood samples were obtained on postoperative days 7, 14, and 20 for biochemical examination. The defect was effectively repaired by the autologous vein graft and stent in 7 dogs, after the exclusion of 1 dog that died of hemorrhage 3 days after the operation. No change in blood biochemistry was observed postoperatively, and no histopathological change in the liver was found in the preoperative or postoperative periods. These findings indicate that the use of an autologous vein graft and stent to repair CBD injuries may be a feasible and alternative method of treatment.

Rothmund Thomson syndrome associated with esophageal stenosis: report of a case

Rothmund Thomson syndrome (RTS) is a rare autosomal recessive disorder which is primarily diagnosed by clinical manifestations that include poikiloderma, short stature, sparse hair distribution, juvenile cataracts, small hands and feet, bone defects, photosensitivity, hypogonadism, defective dentition, onychodystrophy, and hyperkeratosis. Although a few reports have been published on patients with RTS associated with gastrointestinal abnormalities, to our knowledge the case described herein is the first documentation of a patient with RTS having upper esophageal stenosis.

The influence of sphincterotomy and hepatic plexus vagotomy on ascending infections of the biliary tract: an experimental study in dogs

BACKGROUND/AIMS

Hypertonic dyskinesia of the sphincter of Oddi is an important factor in the pathogenesis of postcholecystectomy syndrome, and this condition is usually treated by endoscopic sphincterotomy. However, it has been demonstrated that the biliary tract may also be contaminated after sphincterotomy. In various experimental studies, it has been established that the choledochal pressure decreases by a mean of 32% to 28% after hepatic plexus vagotomy. This experimental study was performed to investigate whether hepatic plexus vagotomy and/or sphincterotomy result in contamination of the biliary tract.

METHODOLOGY

Thirty street dogs were divided into three equal groups. The three groups underwent simple laparotomy, transduodenal papillotomy, hepatic plexus vagotomy, respectively, and gallbladder bile samples were taken from all of them. Relaparotomy was performed after four weeks, and again, bile samples were taken from the gallbladder. All bile samples were examined microbiologically.

RESULTS

Bacteria were not found in the first bile samples taken from the three groups. Bacteria were not found in the bile samples taken during the second surgery in the simple laparotomy and hepatic plexus vagotomy groups. However, both aerobic and anaerobic bacteria were found in the papillotomy group in seven of the ten dogs.

CONCLUSION

These results demonstrate that hepatic plexus vagotomy decreased choledochal pressure and did not cause contamination of the biliary tract. It may be a treatment of choice to prevent postcholecystectomy syndrome resulting from sphincter of Oddi dysfunction.

Blood and tissue findings in the diagnosis of mesenteric ischaemia: an experimental study

In this experimental study, after inducing mesenteric ischaemia in dogs, we investigated routine blood biochemistry, serum malondialdehyde (MDA) levels, histopathological changes and tissue MDA levels in the liver and intestines. The study group included 10 dogs. Six dogs which underwent sham operation served as controls. In the study group, the MDA level in liver tissue increased after superior mesenteric artery (SMA) ligation. Various degrees of necrosis were seen in the ileal biopsies 10 hours after the ligation. Hyperaemia and focal necrosis in the liver accompanied the intestinal necrosis if it was limited within the mucosa. However, massive or centrilobular necrosis was observed in the liver of those dogs which had intestinal necrosis that extended into muscular layers. MDA levels in intestinal tissue measured after SMA ligation were significantly higher than the preligation levels. On the other hand, the difference between serum and tissue MDA levels was not significant. The alterations in MDA were not significant in the sham group. Thus it is concluded that the serum MDA levels are valuable markers of diagnosis in intestinal ischaemia.