Kotaro Nishi

Impact of age at Kasai operation on short- and long–term outcomes of type III biliary atresia at a single institution

PURPOSE We reevaluated the impact of age at Kasai operation on the short- and long-term outcomes of type III biliary atresia (BA). PATIENTS AND METHODS From 1953 to 2009, 242 patients with type III BA underwent Kasai operation at ages ranging between 12 and 421 days (average, 79.7 days). The relationship between age at Kasai operation and jaundice disappearance rates (JDRs), and 10-, 20-, and 30-year native liver survival rates (NLSRs) were assessed retrospectively (JDR [%] = the number of patients in whom jaundice disappeared/the number of patients in each group × 100). RESULTS Age at Kasai operation had a significant impact on the JDRs (P < .001). However, there was no statistical relationship between long-term NLSR of the patients in whom jaundice disappeared after Kasai operation and operative age. From the results of the cumulative NLSRs estimated by Kaplan-Meier method, each survival rate was quite dependent on the age at operation until 30 years after Kasai operation, but the difference became much smaller in the later period provided age at operation was 4 months or younger. CONCLUSION The operative age as a prognostic factor might be less significant in the long-term outcome than in the short-term outcome.

Thermal control of shape memory alloy artificial anal sphincters for complete implantation

This paper presents an approach for the thermal control of an artificial anal sphincter using shape memory alloys. An artificial anal sphincter has been proposed by the authors to resolve problems of severe fecal incontinence in patients. The basic design of the artificial sphincter consists of two all-round shape memory alloy plates as the main functional parts, and heaters that are attached to the SMA plates for generating the thermal cycles required for the phase transformation accompanied shape changes of the plates. The SMA artificial sphincter could be fitted around intestines, performing an occlusion function at body temperature and a release function upon heating. Thermal compatibility of such prostheses is most important and is critical for practical use. Since a temperature rise of approximately 20 °C from body temperature is needed to activate a complete transformation of SMA plates, an earlier model of ours allowed only a short period of heating, resulting in incomplete evacuation. In this work, a thermal control approach using a temperature-responsive reed switch has been incorporated into the device to prevent the SMA plates from overheating. Then, with thermal insulation the artificial anal sphincter is expected to allow a long enough opening period for fecal continence; without any thermal impact to the surrounding tissues that would be in contact with the artificial sphincter. Thermal control was confirmed in both in vitro and in vivo experiments, suggesting the effectiveness of the present approach. The modified SMA artificial anal sphincter has been implanted into animal models for chronic experiments of up to 4 weeks, and has exhibited good performance by maintaining occlusion and release functions. At autopsy, no anomaly due to thermal impact was found on the surfaces of intestines that had been in contact with the artificial anal sphincter.

Functional evaluation of an artificial anal sphincter using shape memory alloys.

This article describes an implantable artificial anal sphincter using shape memory alloys and its in vivo assessment in porcine models. The new design was developed as a low invasive prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients with hypoplastic sphincters or without anal sphincters and especially for ostomates. The artificial anal sphincter consists of two shape memory alloy (SMA) plates as the main functional parts to perform two basic functions when the SMA artificial sphincter is fitted around intestines (i.e., an occlusion at body temperature and an opening function on heating). Our previous assessments with short-term animal experiments revealed promising properties with the occlusion function of the device, although some complications, such as overpressure induced ischemia, heat burn, and infections, remained. This article addresses the concerns related to the practical use of the device, the power supplement to drive the actuator, and overheating protection of the device inside bodies. Results of chronic animal experiments of up to 4 weeks suggested great potential for the improved device.

Postnatal management of prenatally diagnosed biliary cystic malformation

PURPOSE Recent advances in ultrasonography have increased prenatal diagnosis of biliary atresia (BA) and choledochal cyst (CC). These conditions are not easy to distinguish before or just after birth. This study investigated diagnostic and therapeutic problems in prenatal diagnosis of BA and CC. METHODS We retrospectively studied clinical characteristics and progression of hepatobiliary cysts in 10 patients (4 cases of BA, 6 cases of CC) from the time of diagnosis. Chronological changes in cyst size and gallbladder morphology were assessed and measured sequentially by ultrasonography. RESULTS Three cases of BA were type I cyst and 1 case was type III-d. All cases of CC were type Ia. Cyst size decreased between birth and surgery in BA but increased in CC. The gallbladder appeared atrophic in BA. There was no significant difference in gestational age or cyst size at prenatal diagnosis, changes in cyst size between birth and surgery, and degree of liver fibrosis. CONCLUSIONS BA should be suspected if cyst size decreases before and after birth and the gallbladder atrophies after birth. Cholangiography is the only reliable method to differentiate BA from CC. Neonatal surgery is indicated for CC with icterus and liver dysfunction.

Living-related intestinal transplantation for a patient with hypoganglionosis

Abstract:  A 14‐yr‐old boy with total parenteral nutrition‐dependent short‐bowel syndrome associated with hypoganglionosis underwent the LR‐IT by using a 150 cm segment of distal ileum taken from a healthy donor. The graft vessels were connected to infrarenal aorta and inferior vena cava. The immunosuppressive regimen consisted of daclizumab, tacrolimus, and steroid. The graft surveillance for ACR was accomplished using zoom endoscopy and mucosal biopsy. The blood trough level of tacrolimus was maintained between 20 and 25 ng/mL for the first 2 months, followed by 15–20 ng/mL thereafter. The 50 mg of daclizumab was administered on the day of operation, and same dosage was repeated at 2‐wk intervals. The first ACR occurred on POD‐9 and was progressive, and required a 14‐day course of OKT‐3 injection. After the treatment with OKT‐3, the graft recovered from the ACR, and began to function well enough to discontinue the intravenous nutrition on POD‐55. No infectious complication has occurred. The patient was discharged in POD‐112, and currently tolerates full oral intake without requiring intravenous nutritional or fluid supplementation. The donor was discharged without any complications. The LR‐IT could successfully be performed with minimal risk to the donor, and it can be a treatment of choice for patients with short‐gut syndrome associated with hypoganglionosis.