Endoscopic management of malignant biliary obstruction by means of covered metallic stents: primary stent placement vs. re-intervention.

BACKGROUND AND STUDY AIMS: Recent progress in chemotherapy has prolonged the survival of patients with malignant biliary strictures, leading to increased rates of stent occlusion. Occlusion of covered metallic stents now occurs in about half of all patients with malignant biliary strictures. The removal of metallic stents followed by placement of a second stent has been attempted, but outcomes remain controversial. The aim of the current study was to evaluate the effectiveness and safety of the primary placement and secondary placement (re-intervention) of covered metallic stents and to assess the feasibility and safety of stent removal. PATIENTS AND METHODS: The study included 186 patients with unresectable malignant biliary strictures who underwent primary stent placement between October 2001 and March 2010.  Covered biliary self-expandable metal stents (SEMSs) were removed in 39 of these patients, and 36 underwent re-intervention. The patency times, occlusion rates of the first stent and re-intervention, success rates of stent removal, and complications were investigated. RESULTS: Covered SEMSs were placed in 186 patients. The median patency time of the first stent was 352 days. Stent occlusion occurred in 48.9 % of the patients and was mainly caused by debris or food residue (37 %), dislocation (19 %), and migration with hyperplasia (19 %). Stent removal was attempted in 50 patients and was successful without complication in 39 (78 %). Most of the patients in whom stent removal was unsuccessful had migration with hyperplasia. The median patency time of the second stent was 263 days. The stent patency time did not significantly differ between the first and the second stent. CONCLUSIONS: Covered SEMSs could be safely removed at the time of stent occlusion. Patency rates were similar for initial stent placement and re-intervention.

Bone regeneration by synthetic octacalcium phosphate and its role in biological mineralization.

Octacalcium phosphate (Ca8H2(PO4)6 * 5H2O; OCP) has been advocated to be a precursor of biological apatite crystals in bone and tooth. Recent studies, using physical techniques, showed that OCP is present as a transient phase during biological apatite formation in human dentin, porcine enamel and murine bone. However, there is still a controversy regarding the chemical nature of the first mineral formed in the biominerals. A number of studies have demonstrated that synthetic OCP shows bone regenerative and biodegradable characteristics, rather than other calcium phosphate bone substitute materials, such as hydroxyapatite (Ca10(PO4)6(OH)2; HA) ceramic. It seems likely that synthetic OCP may be an alternative to autogenous bone graft. It is known that OCP contains alternative layers of water molecules and an apatite structure, and that the transition of OCP to HA is likely to be spontaneous and irreversible. The conversion process induces modification of local environment adjacent to OCP surface, including the changes in adsorption of serum proteins and concentration of calcium and inorganic phosphate ions. This article reviews the possible application to bone regeneration by synthetic OCP and the mechanism to enhance bone regeneration in relation to biological mineralization in bone and tooth.

Associated injuries and mechanism of atlanto-occipital dislocation caused by trauma.

Injuries associated with traumatic atlanto-occipital dislocation (AOD) leading to death were analyzed in 11 patients, nine injured by traffic accidents, of which five were victims of car-pedestrian accidents. On admission, unconsciousness and respiratory arrest were noted in all patients, and cardiac arrest in nine. Skull and cervical roentgenograms revealed enlargement of the retropharyngeal space due to injury of the vertebral artery or its branches in nine patients, atlanto-axial dislocation (C-1-C-2 separation) in four, and skull fracture in four. Computed tomography demonstrated subarachnoid hemorrhage (SAH) in the upper cervical and posterior fossa in nine patients, fourth ventricular hematoma in seven, and atlas fracture in three. SAH and ventricular hematoma were due to craniocervical injury. Other common injuries were injury of face and head excluding the mandibular region in 10 patients, mandibular fracture in three, severe chest injuries in eight, and intraperitoneal bleeding in two. The overall outcome was poor. Nine patients died within 13 hours of admission, one was diagnosed as brain dead 8 days after the accident, and the other one survived in a persistent vegetative state. Early death is probably caused by associated severe injuries, i.e. chest injuries and intraperitoneal bleeding rather than AOD. Although injury of the mandibular region is known to be associated with AOD, head, breast, and abdominal trauma may also lead to neck hyperextension-flexion in various directions. Whatever the direct cause, a distractive force to the craniocervical joint by hyperextension-flexion appears to be important in the mechanism of AOD.

[A case of anaphylaxic shock due to latex glove used on internal examination and on the probe of intrauterine echogram].

A 15 year old female with uterus bicornis bicollis was admitted for operation. She had a history of atopic dermatitis and allergy to buckwheat, raw egg and latex. Two months previously she had developed whole body flushing during dental treatment, and latex glove used by the dentist had been suspected as the cause. Prior to the operation she underwent internal examination and intrauterine echogram in which a latex glove was carelessly used by another gynecologist who had not confirmed her past history. After 30 minutes, dyspnea and urticaria without itching, appeared suddenly. Blood pressure decreased to 80/50 mmHg and heart rate increased to 120 beats.min-1. She was then transferred to our ICU. Methylprednisolone was administered intravenously for dyspnea and circulatory collapse. After 3 hours, the patient made an uneventful recovery. The increased plasma latex protein-specific IgE levels confirmed anaphylaxis to latex. The increasing incidence of potentially life-threatening allergic reactions to latex has caused mounting concern over recent years. We may suspect latex allergy when an anaphylaxic reaction or shock of unknown origin occurs. In hospitals, latex free products must be prepared for use with latex allergic patients and for protection of medical staff with this allergy.