Relation between vertical orientation and stability of acetabular component in the dysplastic hip simulated by nonlinear three-dimensional finite element method

In acetabular dysplasia, more vertical orientation of the acetabular component is often used to minimize the superolateral bone grafting. This study was designed to determine the effects of vertical orientation of the cup on the stability and polyethylene wear of the acetabular component in uncemented total hip arthroplasty (THA). Three-dimensional finite element models of the hemipelvis with dysplastic acetabulum were developed. Metal-backed hemispherical cups were placed in the true acetabulum with abduction angles of 35, 45, 55, and 65 degrees. It was found that more vertical orientation of the cup was associated with larger relative motion of the metal shell between the acetabulum and metal shell. Furthermore, tilting and torsional shear stresses in the model of the cup abduction angle of 65 degrees were found to be 1.7 times larger than that in the model with 35 degrees at the bone-metal shell interface. More vertically oriented cups caused larger contact stresses at the articulating surfaces of the polyethylene liners. The results suggest that the abduction angle of the acetabular component significantly influences cup loosening and polyethylene wear in THA.     

A case of transitional cell carcinoma of the renal pelvis with adenocarcinoma producing CEA and CA19-9

We report a case of invasive renal pelvic tumor with high serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA 19-9). An 86-year-old man presented with macrohematuria. Retrograde pyelography demonstrated a filling defect in right upper calyx, suspected of renal pelvic tumor. The levels of serum CEA and CA 19-9 were elevated to 28.0 ng/ml and 122 U/ml, respectively. No abnormalities were found in the gastrointestinal tract. Right nephroureterectomy was performed, and histopathological diagnosis was transitional cell carcinoma, grade 2>grade 3, accompanied with adenocarcinoma immuno-stained for CEA and CA19-9. A part of the tumor showed a tubular growth pattern. Both serum levels of CEA and CA 19-9 immediately decreased to the normal range after the operation, but increased again with lung and hepatic metastases.     

Clinicopathological features of peripheral small-sized (2 cm or less in diameter) non-small cell lung cancer

Ninety-three patients with completely resected peripheral non-small cell lung cancer, clinically diagnosed 2 cm or less in diameter, were retrospectively reviewed. Their preoperative computed tomography (CT) and positron emission tomography (PET) findings, carcinoembryonic antigen (CEA) values, clinico-pathological features and postoperative outcomes were analysed. Ground-glass opacity (GGO) ratio( soft tissue density area of the tumor/maximum area of the tumor in diameter) was measured. The overall survival rate at 3 years was 93.3% and the relapse-free survival rate at 3 years was 89.4% with a median follow-up period of 38.5 months. Patients with GGO ratio 0.25 or less had no lymph node (LN) involvement nor lymph vascular invasion. Only 2 of them (8%) had vascular invasion. Fisher's exact probability test revealed CEA ≥ 5 ng/ ml as risk factor for LN involvement( p=0.0400). Multiple logistic regression analysis showed that solid adenocarcinoma and squamous cell carcinoma recurred more frequently than adenocarcinoma with GGO (p=0.0619, odds ratio 4.969, 95%CI 0.9242~37.67).     

Genetic alteration in carcinoid tumors of the lung.

Surgically resected specimens of 13 carcinoid tumors of the lung including nine typical carcinoids and four atypical carcinoids, and eight salivary gland type carcinomas (six mucoepidermoid carcinomas and two adenoid cystic carcinomas) were analyzed regarding p53 expression, loss of heterozygosity (LOH) in chromosome 3p, 9p, and K-ras mutation. The overexpression of p53 was identified in four atypical carcinoid tumors, one mucoepidermoid carcinoma, and one adenoid cystic carcinoma, however, none of typical carcinoids showed p53 immunoreactivity. LOH in 3p14 was demonstrated in three of seven informative cases in all tumors. LOH in 9p was demonstrated in two of five informative cases in all tumors. Two of three cases with LOH at 3p14 had a poor prognosis, one of which also had LOH at 9p. No mutation of the K-ras gene was observed in any of these tumors. These data thus indicate that p53 overexpression might distinguish atypical carcinoid tumors from typical tumors and might therefore be useful as an adjunct modality in the differential diagnosis of pulmonary carcinoid tumors. The presence of LOH at 3p14 or 9p may thus help to identify lung cancer patients with a poor prognosis.     

Changes of fiber type ratio and diameter in rabbit skeletal muscle during limb lengthening

 Changes in the fiber-type ratio and diameter during limb lengthening in 10 adult rabbits were studied using histochemical techniques. Changes in the ratio and diameter of muscle fibers (classified as type 1, 2A, or 2B fibers) in tibialis anterior muscles were examined after 20% gradual distraction of the tibia. There was an increase in the number of type 1 fibers and a decrease in type 2B fibers after tibial lengthening. Moreover, the average diameter of the type 1 fibers increased, whereas that of the type 2B fibers decreased. The diameters of muscle fibers measured immediately after completion of the lengthening showed a tendency to recover to normal levels within 1 month; however, the ratio profile of the muscle fibers changed both immediately and 1 month after lengthening. The above results demonstrate that stretched skeletal muscle adapts differently to bone lengthening according to the type of muscle fibers present, resulting in qualitative changes in the fiber-type profile. Received: February 1, 2002 / accepted: August 26, 2002 Acknowledgments. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan. Offprint requests to: H. Yamazaki, 4-21-2 Kurakuen, Nishi-nomiya 662-0088, Japan     

Experimental analyses of the cavitation generated by ultrasonically activated surgical devices

Purpose

Recently, the incidence of postoperative pancreatic leakage has been reported to have significantly increased after laparoscopic gastrectomy for gastric cancers in comparison to open surgery. Although their lateral thermal spread has been shown to be smaller than that of other electrosurgical devices, ultrasonically activated surgical devices (USADs) have been suggested as one of the causes. We therefore hypothesized that cavitation generated by USADs could cause injuries to pancreatic tissue. Our retrospective study showed that the amylase activity in the drainage fluid of patients in whom surgery was performed using a USAD with a curved blade was significantly higher than that in patients in whom surgery was performed using a USAD with a straight blade. We therefore focused on the effects of straight and curved USAD blades.

Methods

The distribution of microbubbles generated in degassed water, which produce mechanical and biological tissue destructive forces, was measured and compared between the two types of USAD.

Results

More microbubbles were found to be generated from the side aspect of the curved blade, and the mechanical and biological destructive forces were found to be significantly higher than those generated by the side aspect of the straight blade.

Conclusions

These findings strongly suggest that cavitation generated by USADs could injure pancreatic tissues in the clinical cases. Surgeons should be aware of these properties of devices to achieve safe and secure surgeries.

     

Atlantoaxial transarticular screw fixation and posterior fusion using ultra-high-molecular-weight polyethylene cable

This article attempts to evaluate the effectiveness of the ultra-high-molecular-weight polyethylene (UHMW-PE) cable system in atlantoaxial transarticular screw fixation and posterior fusion through the clinical results of 10 postoperative patients with atlantoaxial subluxation secondary to rheumatoid arthritis. Among them, one patient with only one screw placed owing to an anomalous vertebral artery had the correction loss of the 3-mm atlas-dens interval after surgery. Another patient had a second operation to remove the screw and cable after 2 years 11 months because a unilateral transarticular screw had come to protrude through the lateral mass of the atlas ventrally. All patients had achieved C1-C2 osseous fusion without any complications associated with this cable system. The UHMW-PE cable is a very useful material as sublaminar wiring in atlantoaxial transarticular screw fixation and posterior fusion.     

Smoke inhalation injury: diagnosis and respiratory management

Smoke inhalation is a significant comorbid factor following major thermal injury. Smoke exposure is only a trigger for the sequence of events responsible for the development of inhalation injury. Noxious chemicals generated by incomplete combustion injure the exposed bronchoepithelium and stimulate the release of chemical mediators that cause a progressive inflammatory process. Airway inflammation and pulmonary edema impair gas exchange and increase the susceptibility to pulmonary infection. Earlier diagnosis and treatment of inhalation injury is an important element to improve the clinical course of severe burn patients. The American Burn Association, however, recently concluded that there are insufficient data to support a treatment standard for the diagnosis of inhalation injury. At present, the diagnosis of inhalation injury is supported by the combination of history, physical examination, bronchoscopy, and laboratory findings For accurate diagnosis of inhalation injury, helical CT scanning and examination to detect activated leukocytes in bronchoalveolar lavage fluid may be warranted. In the respiratory management of inhalation injury, repeated removal of pseudomembrane by fiberoptic bronchoscopy and the use of adequate PEEP to avoid airway obstruction are essential. High-frequency percussive ventilation can be a suitable mode of ventilation for inhalation injury.     

Comparison of laparoscopy-assisted and open pylorus-preserving pancreaticoduodenectomy for periampullary disease

Background

Although many reports have described laparoscopic pancreatic surgery, pancreaticoduodenectomy (PD) has not been widely accepted. The present study aimed to compare laparoscopy-assisted and open pylorus-preserving pancreaticoduodenectomy (PPPD) to investigate the feasibility, safety, and tumor clearance.

Methods

Fifteen patients with periampullary disease underwent laparoscopy-assisted PPPD, in which resection was performed laparoscopically and the reconstruction was performed through a small midline incision. These patients were compared with 15 patients who, during the same period, underwent conventional open PPPD.

Results

Mean operative time and mean blood loss were similar between groups. No significant differences in the incidence of complications or hospital stay were noted between groups. Surgical margin and number of lymph nodes found in the resected specimen did not differ between groups.

Conclusions

Laparoscopy-assisted PPPD is on the same level with conventional open surgery in terms of perioperative outcomes or treatment efficacy.     

Long-term clinical outcome of acetabular cup revision surgery: comparison of cemented cups,cementless cups,and cemented cups with reinforcement devices

The aim of the present study was to analyze the clinical and radiographic outcomes and Kaplan–Meier survivorship of patients who underwent revision surgeries of the acetabular cup that had sustained aseptic loosening. We reviewed 101 consecutive patients (120 hips; 10 men 11 hips; 91 women 109 hips; age at surgery 66 years; range 45–85) who underwent acetabular component revision surgery, at a follow-up period of 15.6 years (range 10–32). To evaluate the state of the acetabulum, acetabular bony defects were classified according to the AAOS classification based on intraoperative findings: type I (segmental deficiencies n = 24 hips), type II (cavity deficiency n = 48), type III (combined deficiency n = 46), and type IV (pelvic discontinuity n = 2). The Harris hip score improved from 42.5 ± 10.8 (mean ± SD) before surgery to 74.9 ± 14.6 points at follow-up. The survival rates of the acetabular revision surgery with cemented, cementless, and cemented cups plus reinforcement devices were 74, 66, and 82 %, respectively. The difference in the survival rate between the cemented and cementless group was marginal (p = 0.048 Gehan–Breslow–Wilcoxon, p = 0.061 log-rank), probably due to the early-stage failure cases in the cementless group. The cementless and reinforcement groups included nine early-stage failure cases. To prevent early-stage failure, we recommend the cementless cups for types I and II acetabular bone defects with adequate contact between host bone and acetabular component, and the cemented cup with or without reinforcement devices, together with restoration of bone stock by impaction or structured bone grafting, for cases lacking such contact.