Diagnosis of inguinal hernia by prone- vs. supine-position computed tomography

PURPOSE

The aim of this study was to investigate the efficacy of prone-position computed tomography (CT) for detecting and classifying inguinal hernia relative to supine-position CT before laparoscopic inguinal hernia repair.

METHODS

Seventy-nine patients who underwent laparoscopic transabdominal preperitoneal repair of inguinal hernia were enrolled in this prospective study. Patients diagnosed with inguinal hernia by physical examination underwent abdominal CT in the supine and prone positions for preoperative assessment. The anatomy of the right and left inguinal regions was confirmed during the surgery and compared with the preoperative CT findings.

RESULTS

The 79 cases included 87 operated lesions and 71 non-operated contralateral inguinal sites. Of the 84 clinical hernias, inguinal hernia was detected significantly more frequently on prone-position CT images (84, 100%) than on supine-position CT images (55, 65.5%). In addition, the inguinal hernia type was determined with significantly greater accuracy on prone-position CT images (96.4%) than on supine-position CT images (58.3%). Twenty-two occult hernias were detected by laparoscopy. The detection rate and accuracy for determining the type of occult hernia were significantly greater when using prone-position CT images [19 of 22 lesions (86.4%) and 77.3%, respectively] than when using supine-position CT images [8 of 22 lesions (36.4%) and 27.3%, respectively].

CONCLUSIONS

Prone-position CT is adequate for detecting and classifying inguinal hernia and for evaluating occult hernia.

Gelatin Density Gradient for Isolation of Islets of Langerhans

Isolation of islets of Langerhans (islets) has been performed by means of collagenase digestion of the pancreatic tissue combined with density gradient separation of islets from unwanted exocrine tissues. An enormous number of islets are necessary for clinical islet transplantation. The density gradient used for isolation of a large number of islets should satisfy several requirements in addition to those for the conventional density gradients, such as high viscosity for creating fine interfaces with a large area, easy sterilization, and low cost. This study is concerned with the development of a new density gradient made of low-molecular-weight gelatin. We isolated islets from the hamster pancreatic tissue using the gelatin density gradients. The yield and purity of islet and its insulin release function were compared with those of islets isolated using Ficoll and Ficoll-Conray density gradients that have been conventionally used. The new gelatin density gradient can separate islets from the unwanted exocrine tissue as effectively as the Ficoll density gradient and more effectively than the Ficoll-Conray density gradients. The islets collected using the gelatin gradient retain ability of insulin release increase in response to glucose stimulation, similar to those isolated by the Ficoll-Conray gradient and more than those collected by the Ficoll gradient. In addition, the gelatin effectively inhibited enzyme activities, that is, collagenase and proteolytic enzymes released from the exocrine tissue, and thus it can inhibit overdigestion of islets during their density gradient isolation. The gelatin gradient satisfies most of the additional requirements for islet isolation from the pancreatic tissue of large animals mentioned above. Although several factors, such as molecular weight of gelatin, osmolality of the gradient, and centrifugal conditions, still remain to be optimized, our results suggest that the gelatin gradient has potentiality to isolate islets from the pancreatic tissue of a large animal.

Overall Activity of All Masticatory Muscles during Lateral Excursion

Quantification of the overall activity of every masticatory muscle is requisite for the analysis of stomatognathic function, which has not been accomplished by conventional electromyography. We used positron emission tomography and 18F-fluoro-deoxy-glucose to quantify the overall activity of every masticatory muscle during lateral excursion, and to evaluate the relative contribution of each masticatory muscle to lateral excursion. The present study suggested that lateral and medial pterygoid muscles are more responsible for lateral excursion than are masseter and temporal muscles. In particular, the contralateral lateral pterygoid muscle plays a major role, followed by the contralateral medial pterygoid muscle.