Long-term follow-up for superior vena cava filter placement

The short-term effectiveness and safety placement of superior vena cava (SVC) filter in the treatment of upper extremity deep venous thrombosis in patients with contraindication to anticoagulation have been well documented. However, as opposed to the numerous reported experiences with inferior vena cava filter placement and its complications, there has been no documented long-term follow-up on SVC filter placement. We, therefore, reviewed our experience with SVC filter placement. A retrospective review was performed of the 154 cases of patients who underwent SVC filter placement between January 1994 and August 2005 at our institution. Seven additional patients had unsuccessful SVC filter placement due to widespread deep venous thrombosis. The data were evaluated for both insertion complications (pneumothorax, hemorrhage, filter misplacement) and long-term complications (pulmonary embolism, migration, caval occlusion). The follow-up included review of serial chest radiographs to evaluate for filter migration in patients who lived at least 60 days after filter insertion and had chest radiography performed (n = 40), patients' charts, clinic visits, and telephone contacts, hospital databases, city death records, and national databases. There were 69 males and 85 females with a mean age of 73.6 years (range, 16-96 years; +/-15.3 [SD] years). Follow-up ranged from 1 day to 3750 days (256.3 +/- 576 days [mean +/- SD]) and 5 patients were lost to follow-up. Of the 154 patients, 58 survived longer than 60 days with mean follow-up of 628.4 days. All SVC filters (TrapEase, n = 38; Greenfield, n = 116) were successfully deployed in the 154 patients. During the follow-up, 114 (74.0% mortality) of the patients died of chronic illness or from cancer complications. There were three cases of pericardial tamponade (1.9%), and one case of misplaced filter in innominate vein. There were no known cases of symptomatic pulmonary embolism, caval occlusion, pneumothorax, or filter migration. SVC filter placement is associated with a low incidence of complications with long-term follow-up. These data help to reaffirm the safety and effectiveness of SVC filter placement. However, SVC perforation in young males remains a significant issue.     

Staged management of giant abdominal wall defects: acute and long-term results

INTRODUCTION: Shock resuscitation leads to visceral edema often precluding abdominal wall closure. We have developed a staged approach encompassing acute management through definitive abdominal wall reconstruction. The purpose of this report is to analyze our experience with this technique applied to the treatment of patients with open abdomen and giant abdominal wall defects. METHODS: Our management scheme for giant abdominal wall defects consists of 3 stages: stage I, absorbable mesh insertion for temporary closure (if edema quickly resolves within 3-5 days, the mesh is gradually pleated, allowing delayed fascial closure); stage II, absorbable mesh removal in patients without edema resolution (2-3 weeks after insertion to allow for granulation and fixation of viscera) and formation of the planned ventral hernia with either split thickness skin graft or full thickness skin closure over the viscera; and stage III, definitive reconstruction after 6-12 months (allowing for inflammation and dense adhesion resolution) by using the modified components separation technique. Consecutive patients from 1993 to 2001 at a single institution were evaluated. Outcomes were analyzed by management stage, with emphasis on wound related morbidity and mortality, and fistula and recurrent hernia rates. RESULTS: Two hundred seventy four patients (35 with sepsis, 239 with hemorrhagic shock) were managed. There were 212 males (77%), and mean age was 37 (range, 12-88). The average size of the defects was 20 x 30 cm. In the stage I group, 108 died (92% of all deaths) because of shock. The remaining 166 had temporary closure with polyglactin 910 woven absorbable mesh. As visceral edema resolved, bedside pleating of the absorbable mesh allowed delayed fascial closure in 37 patients (22%). In the stage II group, 9 died (8% of all deaths) from multiple organ failure associated with their underlying disease process, and 96% of the remaining 120 had split-thickness skin graft placed over the viscera. No wound related mortality occurred. There were a total of 14 fistulae (5% of total, 8% of survivors). In the stage III group, to date, 73 of the 120 have had definitive abdominal wall reconstruction using the modified components separation technique. There were no deaths. Mean follow-up was 24 months, (range 2-60). Recurrent hernias developed in 4 of these patients (5%). CONCLUSIONS: The staged management of patients with giant abdominal wall defects without the use of permanent mesh results in a safe and consistent approach for both initial and definitive management with low morbidity and no technique-related mortality. Absorbable mesh provides effective temporary abdominal wall defect coverage with a low fistula rate. Because of the low recurrent hernia rate and avoidance of permanent mesh, the components separation technique is the procedure of choice for definitive abdominal wall reconstruction.     

Preoperative beta-blocker use: impact of national guidelines on clinical practice

STUDY OBJECTIVE: To determine if recommendations regarding perioperative beta-blocker therapy were followed by an increase in the number of eligible presurgical patients receiving beta-blockers and the number achieving the recommended heart rate (HR <60 beats per minute [bpm]). DESIGN: Retrospective, observational study. SETTING: Tertiary-care teaching hospital. MEASUREMENTS: The records of all 718 patients who underwent elective vascular surgery or coronary artery bypass grafting between January 2001 and March 2002 (pre-guideline) and those who did so between April 2002 and September 2003 (post-guideline) were reviewed. Percentage of eligible patients who received beta-blockers preoperatively and the target HR achieved in pre-guideline versus post-guideline patients were recorded. Differences were assessed using the unpaired t test and chi2 analysis. A P value of less than 0.05 is reported. MAIN RESULTS: Fifty percent of the post-guideline patients in the vascular surgery group were receiving beta-blockers at the time of preanesthetic evaluation versus 48% of pre-guideline patients (P = nonsignificant [NS]). Mean HR in the vascular surgery post-guideline beta-blocker group (70 +/- 14 bpm) was higher than in the pre-guideline beta-blocker group (65 +/- 11 bpm) (P < 0.01). Only 22% of those vascular surgery patients in the post-guideline group who were taking beta-blockers achieved the target HR of less than 60 bpm versus 29% of the vascular surgery patients taking beta-blockers in the pre-guideline group (P = NS). In the coronary artery bypass grafting group, 80% of post-guideline patients received beta-blocker before anesthesia assessment versus 75% of pre-guideline patients (P = NS). Mean HR in the post-guideline beta-blocker group (67 +/- 15 bpm) was similar to the pre-guideline beta-blocker group (64 +/- 13 bpm) (P = NS). Only 28% of the post-guideline patients who were receiving beta-blockers achieved the target HR of less than 60 bpm, which was not significantly different from the 17% achieved in the pre-guideline group (P = NS). CONCLUSION: At our institution, preoperative beta-blocker use was not significantly changed by publication of the recommendations.     

Attenuated Salmonella typhimurium with interleukin 2 gene prevents the establishment of pulmonary metastases in a model of osteosarcoma

Purpose

The current management of osteosarcoma (OS) entails an aggressive preoperative and postoperative chemotherapeutic regimen with limb salvage surgery. Despite these efforts, relapse-free survival is less than 60% in patients with classic OS, whereas most patients relapse with pulmonary metastases. In these studies, we sought to prevent the establishment of pulmonary metastases from OS with a single oral dose of SalpIL2.

Methods

Mice were administered attenuated Salmonella typhimurium with (SalpIL2) and without a gene for human interleukin 2 (Sal-NG) 7 days before challenge with 2 × 10⁵ OS cells via tail vein. Three weeks after injection, mice were harvested for splenic lymphocytes and tumor enumeration.

Results

Prophylaxis with attenuated SalpIL2 significantly reduces pulmonary metastases in number and volume (P < .0001 and P < .0001) with respect to saline controls. Furthermore, splenic natural killer cell populations were increased 396% with SalpIL2 (P < .0007) and 426% with Sal-NG (P < .0003) compared to nontreated groups.

Conclusions

Host natural killer response is greatly amplified and maybe partially responsible for the effective immune response against the formation of pulmonary metastases. A single oral dose of SalpIL2 may be a novel form of adjuvant therapy for patients after early detection of primary OS.     

The anatomy of the cremaster muscle during inguinoscrotal testicular descent in the rat

Background

Extrapolation of rat testicular descent studies to humans has been criticized because of anatomical differences of the cremaster muscle. Human cremaster is described as a thin strip rather than a large, complete sac as in rats, which is proposed to be more important in propelling the testis during descent. This study investigated cremaster muscle anatomy and ontogeny in both normal and cryptorchid rat models.

Methods

Gubernacula from 4 groups of neonatal rats were sectioned longitudinally and transversely: normal Sprague-Dawley, capsaicin pretreated, flutamide pretreated, and congenital cryptorchid rats. Gubernacula were stained with hematoxylin-eosin, Masson trichrome, and desmin immunohistochemistry to study muscle development.

Results

Myoblasts are more numerous at the gubernacular tip, whereas the most differentiated muscle is proximal. Rat cremaster develops as an elongated strip rather than a complete sac derived from abdominal wall muscles. Flutamide and capsaicin pretreatment disrupts development.

Conclusion

Rat cremaster muscle develops as a strip, bearing close resemblance to human cremaster muscle, permitting extrapolation of cremaster function to human testicular descent. The cremaster muscle appears to differentiate from the gubernacular tip during elongation to the scrotum, and requires intact sensory innervation and androgen.     

Multiple-gland disease in primary hyperparathyroidism: a function of operative approach?

HYPOTHESIS: The approach to surgery for primary hyperparathyroidism (PHPT) is controversial. To determine whether routine bilateral neck exploration increases the detection of multiple-gland disease compared with a focused unilateral approach, we compared the incidence of single vs multiple-gland disease in patients undergoing surgical treatment for PHPT as a function of unilateral or bilateral exploration. DATA SOURCES: From 1993 through 1997, 214 consecutive patients underwent initial bilateral neck exploration for PHPT by a single surgeon. Each patient underwent the surgical procedure without prior localizing studies. Four parathyroid glands were identified, and abnormal glands were excised. The results were compared with published studies of patients who underwent either bilateral neck exploration or focused unilateral neck exploration for PHPT. STUDY SELECTION: All reported studies from 1995 through 2001 in a MEDLINE search using the terms "parathyroidectomy" or "primary hyperparathyroidism and surgery" and either "bilateral" or "conventional" or "minimally invasive," "selective," or "unilateral." DATA EXTRACTION: The studies were analyzed for numbers of patients and a final diagnosis of either a single adenoma or multiple-gland disease (double adenoma or hyperplasia). Proportions were compared statistically with a chi(2) test. DATA SYNTHESIS: In our series of 214 patients who underwent bilateral neck exploration, 79.4% had a single adenoma, and 20.6% had multiple-gland disease. Of 2166 patients in 14 studies who underwent bilateral neck exploration, 79.7% had a single adenoma, and 19.3% had multiple-gland disease. Of 2095 patients in 31 studies with a focused unilateral approach, 92.5% had a single adenoma, whereas only 5.3% had multiple-gland disease. The incidence of multiple-gland disease was significantly lower among patients treated with a focused unilateral approach compared with a bilateral approach as used in our series and the literature (P<.001). CONCLUSION: The data suggest that a focused unilateral surgical approach for PHPT may underestimate the incidence of multiple-gland disease.     

Predictors of short and long term outcome in patellofemoral pain syndrome: a prospective longitudinal study

Background  

Patellofemoral pain syndrome (PFP) is a common musculoskeletal condition that has a tendency to become chronic and problematic in a proportion of affected individuals. The objective of this study was to identify prognostic factors that may have clinical utility in predicting poor outcome on measures of pain and function in individuals with PFP.     

A Comparison of the Efficacy of Various Antioxidants on the Oxidative Stability of Irradiated Polyethylene

Background

Ultrahigh-molecular-weight polyethylene (UHMWPE) is subjected to radiation crosslinking to form highly crosslinked polyethylene (HXLPE), which has improved wear resistance. First-generation HXLPE was subjected to thermal treatment to reduce or quench free radicals that can induce long-term oxidative degeneration. Most recently, antioxidants have been added to HXLPE to induce oxidative resistance rather than by thermal treatment. However, antioxidants can interfere with the efficiency of radiation crosslinking.

Questions/purposes

We sought to identify (1) which antioxidant from among those tested (vitamin E, β-carotene, butylated hydroxytoluene, or pentaerythritol tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]) causes the least reduction of crosslinking; (2) which promotes the greatest oxidative stability; and (3) which had the lowest ratio of oxidation index to crosslink density.

Methods

Medical-grade polyethylene (PE) resin was blended with 0.1 weight % of the following stabilizers: alpha tocopherol (vitamin E), β-carotene, butylated hydroxytoluene (BHT), and pentaerythritol tetrakis [methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (a hindered phenol antioxidant [HPAO]). These blends were compression-molded into sheets and subjected to electron beam irradiation to a dose of 100 kGy. Equilibrium swelling experiments were conducted to calculate crosslink density. Each PE was subjected to accelerated aging for a period of 2 weeks and Fourier transform infrared spectroscopy was used to measure the maximum oxidation. Statistical analysis was conducted using analysis of variance with Fisher’s protected least significant difference in which a p value of < 0.05 was used to define a significant difference.

Results

The least reduction of crosslinking in antioxidant-containing HXLPE was observed with HPAO, which had a crosslink density (n = 6) of 0.167 (effect size [ES] = 0.87; 95% confidence interval [CI], 0.162–0.173) mol/dm³ compared with 0.139 (ES = 1.57; 95% CI, 0.132–0.146) mol/dm³ (p = 0.020) for BHT, 0.131 (ES = 1.77; 95% CI, 0.123–0.139) mol/dm³ (p = 0.004) for β-carotene, and 0.130 (ES = 1.79; 95% CI, 0.124–0.136) mol/dm³ (p = 0.003) for vitamin E, whereas pure HXLPE had a crosslink density of 0.203 (95% CI, 0.170–0.235) mol/dm³ (p = 0.005). BHT-PE had an oxidation index of 0.21 (ES = 13.14; 95% CI, 0.19–0.22) followed by HPAO-PE, vitamin E-PE and β-carotene-PE, which had oxidation indices of 0.28 (ES = 9.68; 95% CI, 0.28–0.29), 0.29 (ES = 9.59; 95% CI, 0.27–0.30), and 0.35 (ES = 6.68; 95% CI, 0.34–0.37), respectively (p < 0.001 for all groups). BHT-PE had the lowest ratio of oxidation index to crosslink density of the materials tested (1.49, ES = 1.94; 95% CI, 1.32–1.66) followed by HPAO-PE (1.70, ES = 1.52; 95% CI, 1.61–1.80), vitamin E-PE (2.21, ES = 0.52; 95% CI, 2.05–2.38), and β-carotene-PE (2.69, ES = -0.43; 95% CI, 2.46–2.93) compared with control PE (2.47, 95% CI, 2.07–2.88) with β-carotene (p = 0.208) and vitamin E (p = 0.129) not being different from the control.

Conclusions

BHT-modified HXLPE was found in this study to have the lowest oxidation index as well as the lowest ratio of oxidation index to crosslink density compared with vitamin E, HPAO, and β-carotene-modified HXLPEs. More comprehensive studies are required such as wear testing using joint simulators as well as biocompatibility studies before BHT-modified HXLPE can be considered for clinical use.

Clinical Relevance

BHT is a synthetic antioxidant commonly used in the polymer industry to prevent long-term oxidative degradation and has been approved by the FDA for use in cosmetics and foodstuffs. It may be an attractive potential stabilizer for HXLPE in total joint replacements.     

Dexmedetomidine versus propofol for prolonged sedation in critically ill trauma and surgical patients

Backgroundand Purpose: Currently, dexmedetomidine versus propofol has primarily been studied in medical and cardiac surgery patients with outcomes indicating safe and effective sedation. The purpose of this study was to assess the efficacy of dexmedetomidine versus propofol for prolonged sedation in trauma and surgical patients.MethodsThis was a single-center prospective study conducted in the Trauma/Surgical Intensive Care Unit (ICU) at a Level I academic trauma center. It included patients 18 years of age or older requiring mechanical ventilation who were randomly assigned based on unit bed location to receive either dexmedetomidine or propofol. The primary outcome was duration of mechanical ventilation. Secondary outcomes included mortality; proportion of time in target sedation; incidence of delirium, hypotension, and bradycardia; and ICU and hospital length of stay (LOS).ResultsA total of 57 patients were included. Baseline characteristics were similar between groups. There was no significant difference in duration of mechanical ventilation (median [IQR]) between the dexmedetomidine (78.5[125] hours) and propofol (105[130] hours; p = 0.15) groups. There was no difference between groups in ICU mortality, ICU and hospital LOS, or incidence of delirium. Safety outcomes were also similar. Patients in the dexmedetomidine group spent a significantly greater percentage of time in target sedation (98[8] %) compared to propofol group (92[10] %; p = 0.02).ConclusionsOur results suggest that, similar to medical and cardiac surgery patients, dexmedetomidine and propofol are safe and effective sedation agents in critically ill trauma and surgical patients; however, dexmedetomidine achieves target sedation better than propofol for this specific population.     

Prospective Evaluation of the Change of Predialysis Protein‐Bound Uremic Solute Concentration With Postdilution Online Hemodiafiltration

Although protein‐bound uremic compounds have been related to outcome in observational studies, few current dialysis strategies provide more removal of those compounds than standard hemodialysis. We evaluated the evolution of protein‐bound uremic solutes after a switch from high‐flux hemodialysis to postdilution hemodiafiltration (n = 13). We compared predialysis solute concentration at 4, 5, and 9 weeks versus baseline for several protein‐bound compounds and water‐soluble solutes, as well as for β₂‐microglobulin. After 9 weeks of postdilution hemodiafiltration, a significant decrease versus baseline could be detected for total concentration of protein‐bound solutes: p‐cresylsulfate (3.98 ± 1.51–3.17 ± 1.77 mg/dL, ?20%, P < 0.01) and 3‐carboxyl‐4‐methyl‐5‐propyl‐2‐furanpropionic acid (0.72 ± 0.52–0.64 ± 0.46 mg/dL, ?11%, P < 0.01). For the other protein‐bound solutes, hippuric acid, indoleacetic acid, and indoxylsulfate, no change in total concentration could be detected. The concentration of the middle molecule, β₂‐microglobulin, decreased as well after 9 weeks of postdilution hemodiafiltration (24.7 ± 9.3–18.1 ± 6.7 mg/L, ?27%, P < 0.01). For water‐soluble compounds, no significant change of concentration was found. Postdilution hemodiafiltration in comparison to high‐flux hemodialysis provided significant reduction of predialysis concentration of protein‐bound compounds, especially those with the highest protein binding, and of β₂‐microglobulin, by ?11 to ?27% in 9 weeks.