Ureteral Obstruction: Is the Full Metallic Double-Pigtail Stent the Way to Go?

Background

The Resonance metallic ureteral stent (Cook Medical, Bloomington, Indiana, USA) has been introduced for the management of extrinsic-etiology ureteral obstruction for time periods up to 12 mo.

Objective

The current study aims to determine short- and medium-term effectiveness of the Resonance stent in malignant and benign ureteral obstruction.

Design, setting, and participants

In total, 50 patients with extrinsic malignant obstruction (n = 25), benign ureteral obstruction (n = 18), and previously obstructed mesh metal stents (n = 7) were prospectively evaluated.

Intervention

All patients were treated by Resonance stent insertion. Twenty stents were inserted in antegrade fashion, and the remaining stents were inserted in a retrograde approach. No patient dropped out of the study. The follow-up evaluation included biochemical and imaging modalities.

Measurements

We evaluated the technical success rate, stricture patency rate, complications, and the presence and type of encrustation.

Results and limitations

The technical success rate of transversal and stenting of the strictures was 100%. In 19 patients, balloon dilatation was performed prior to stenting. The mean follow-up period was 8.5 mo. The stricture patency rate in patients with extrinsic malignant ureteral obstruction was 100% and in patients with benign ureteral obstruction 44%. Failure of Resonance stents in all cases of obstructed metal stents was observed shortly after the procedure (2–12 d). In nine cases, stent exchange was demanding. Encrustation was present in 12 out of 54 stents.

Conclusions

The Resonance stent provides safe and sufficient management of malignant extrinsic ureteral obstruction. Resonance stent use in benign disease needs further evaluation, considering the untoward results of the present study.     

Endoscopic stenting for gastric outlet obstruction in patients with unresectable antro pyloric cancer. Systematic review of the literature and final results of a prospective study. The point of view of a surgical group

Background

The authors report the final results of a prospective single-center randomized study whose aim was to compare the endoscopic placement of self-expandable stents with open surgical gastroenterostomy to relieve gastric outlet obstruction (GOO) in patients with advanced antropyloric adenocarcinoma. A systematic review of the medical literature from December 1999 to December 2011 was carried out to determine the results of endoscopic stenting in patients with GOO from unresectable primary cancer of the antropyloric region.

Methods

In the prospective study, 18 patients with advanced adenocarcinoma of the antropyloric region and symptoms of GOO were enrolled. In 9 patients, self-expandable stents were placed, and in 9 patients, open surgical gastroenterostomy was performed. Patients were followed until death. Six hundred seventy-two patients with primary unresectable cancer of the antropyloric region and GOO syndrome who underwent endoscopic stenting were identified from the literature.

Results

In the prospective study of 18 patients, there was no case of postprocedural mortality. Efficient gastric emptying resumed more quickly in patients who received stents, although 3 months after the procedures, there was no difference between the 2 groups. Mean crude survival was 258 days in patients who received stents and 283 days in those who underwent surgical gastroenterostomy (P = NS). In patients who underwent stent placement, there were 2 cases of stent migration and 2 cases of food impaction, which were resolved with endoscopy at a mean follow-up of 70 days. In the 672 patients from the literature, operative mortality and morbidity were very low. In prospective studies, complications related to stents were more common than previously thought.

Conclusions

Endoscopic placement of metallic stents offers an effective therapy in patients with advanced primary adenocarcinoma of the antropyloric region and poor general condition. In patients with longer life expectancies, the form of therapy should be chosen individually, considering that surgical gastroenterostomy has fewer complications in the medium term and that in patients with endoscopic stenting, very careful follow-up is required, with the possibility of new operative endoscopy in half of the patients.     

Outcome of TiNi Stent Treatments in Symptomatic Central Airway Stenoses Caused by Aspergillus fumigatus Infections After Lung Transplantation

Background

Central airway stenoses due to Aspergillus fumigatus infections have been a significant cause of morbidity and mortality after lung transplantation. We reviewed our experience using self-expandable braided TiNi-metallic stents in the management of 4 single-lung transplant recipients with central airways stenoses between January 2003 and June 2010.

Methods

Thirty-six single-lung transplant recipients were subjected to pulmonary function testing and surveillance bronchoscopy with biopsy at predetermined intervals and when clinically indicated. Bronchial wash fluid and biopsy material were examined by appropriate fungal stain and culture techniques.

Results

Nine of 36 patients (25%) were diagnosed with Aspergillus fumigatus infections; 4 (11.1%) showed rapid decrease in pulmonary function and developed severe upper airway narrowings with about 80% of the central airway obstructed by thick plugs of mucus, heavily laden with Aspergillus species. All 4 patients were managed with stent placement as well as antifungal treatments and showed a forced vital capacity and forced expiratory volume in 1 second improvement of 11.3% and 25.9%, respectively after 1 month.

Conclusions

TiNi stent applications in combination with antifungal drugs are sufficient to treat central airway stenoses after lung transplantation.     

The effect of metallic tracheal stents on radiation dose in the airway and surrounding tissues

Background

Metallic airway stents are often used in the management of central airway malignancies. The presence of a metallic foreign body may affect radiation dose in tissue. We studied the effect of a metallic airway stent on radiation dose delivery in a phantom and an in vivo porcine model.

Methods

A metallic tracheal stent was fitted onto a support in a water phantom. Point dosimeters were positioned in the phantom around the support and the stent. Irradiation was then performed on a linear accelerator with and without the stent. Metallic tracheal stents were deployed in the trachea of three pigs. Dosimeters were implanted in the tissues near (Group 1) and away (Group 2) from the stent. The pigs were then irradiated, and the dose perturbation factor was calculated by comparing the actual dose detected by the dosimeters versus the planned dose.

Results

The difference in the dose detected by the dosimeters and the planned dose ranged from 1.8% to 6.1% for the phantom with the stent and 0%–5.3% for the phantom without the stent. These values were largely within the manufacturer's specified error of 5%. No significant difference was observed in the dose perturbation factor for Group 1 and Group 2 dosimeters (0.836 ± 0.058 versus 0.877 ± 0.088, P = 0.220) in all the three pigs.

Conclusions

Metallic airway stents do not significantly affect radiation dose in the airway and surrounding tissues in a phantom and porcine model. Radiation treatment planning systems can account for the presence of the stent. External beam radiation can be delivered without concern for significant dose perturbation.     

Percutaneous valved stent implantation in the ascending aorta for the treatment of very high-risk aortic regurgitation: an animal study

Purpose

We investigated the effects of percutaneous valved stent implantation in the ascending aorta as an alternative treatment for aortic regurgitation in a canine model.

Materials and methods

A total of 16 healthy dogs weighing an average of 18.3 ± 2.1 kg were used for the establishment of animal models of chronic aortic regurgitation by percutaneous aortic valve perforation and balloon dilation. At 2 mo after successful model establishment, all experimental animals underwent valved stent implantation in the ascending aorta and then were followed up for 3 mo.

Results

Experimental models of chronic aortic regurgitation were successfully established in 10 dogs. Surviving dogs underwent successful valved stent implantation in the ascending aorta and were subsequently followed up for 3 mo. The level of instantaneous aortic regurgitation at 3-mo follow-up was significantly reduced compared with that before valved stent implantation (2.4 ± 0.9 versus 10.6 ± 2.1 mL/s, P < 0.05). The left ventricular ejection fraction was significantly increased (53.8 ± 4.2% versus 37.8 ± 3.7%, P < 0.05), and the left ventricular end-diastolic volume was also significantly reduced (30.3 ± 2.2 versus 40.1 ± 3.6 mL, P < 0.05). No paravalvular leak, stroke, atrioventricular block, or other complications occurred in dogs undergoing valved stent implantation.

Conclusions

Percutaneous valved stent implantation in the ascending aorta is feasible, effective, and safe as an alternative treatment for very high-risk aortic regurgitation in a canine model.     

Surgical relief of small bowel obstruction by migrated biliary stent: extraction without enterotomy

Background:

Distal stent migration is a well-known complication following insertion of biliary stents. Most such cases can be managed expectantly, because the stents pass through the gastrointestinal tract. However, small bowel obstruction as a result of the stent mandates surgical intervention.

Methods:

We report the case of a patient who had distal stent migration causing a small bowel obstruction. We successfully retrieved the stent without an enterotomy, by using a combination of laparoscopy, endoscopy, and fluoroscopy. Our unique technique greatly decreased the risk of bacterial peritonitis in this patient with decompensated cirrhosis and associated ascites, which in this patient population results in a high mortality.

Results:

Management of small bowel obstruction secondary to biliary stent migration necessitates operative intervention. Retrieval of a dislodged stent can be performed safely without subjecting the patient to an enterotomy or a small bowel resection. Postoperative morbidity should be significantly reduced by this approach.

Conclusion:

Retrieval of biliary stents in cases of small bowel obstruction without perforation may be successfully performed without enterotomy or bowel resection. A similar approach may be applied to other foreign bodies dislodged in the small bowel.     

Clinical Outcome of Internal Stent for Biliary Anastomosis in Liver Transplantation

Background

This study analyzed the incidence and management of biliary complications after liver transplantation (LT) with or without internal stent.

Methods

The medical record of all patients who underwent LT and were hospitalized from December 2009 to March 2013 were reviewed. Patients were grouped into 2 groups (internal stent group vs no stent group).

Results

There were 29 deceased-donor liver transplantations (58%) and 21 living-donor liver transplantations (42%). There were 2 perioperative mortalities, and those 2 patients were excluded from this study. The overall biliary complication rate was 6.45% in the internal stent group and 17.65% in the no stent group. The rate of anastomotic stricture was 3.23% (n = 1) in the stent group and 11.76% (n = 2) in the no stent group. The rate of bile leak was 3.23% (n = 1) in the stent group and 0% in the no stent group. The rate of biliary obstruction was 0% in the stent group and 5.88% (n = 1) in the no stent group.

Conclusions

The overall rate of biliary complications in the internal stent group was lower than in the no stent group, and most of the biliary complications could be treated successfully with endoscopic or radiologic intervention.     

Blowhole colostomy for the urgent management of distal large bowel obstruction

Background

Complete obstruction of the distal colon or rectum often presents as a surgical emergency. This study evaluated the efficacy of blowhole colostomy versus transverse loop colostomy for the emergent management of distal large intestinal obstruction.

Methods

Retrospective chart review of all colostomy procedures (CPT 44320) performed for complete distal large bowel obstruction during the past 6 y in a university hospital practice was undertaken. Blowhole was compared with loop colostomy with a primary endpoint of successful colonic decompression.

Results

One hundred forty-one patients underwent colostomy creation during the study period. Of these, 61 were completed for acute obstruction of the distal colon or rectum (19 blowhole versus 42 loop colostomy). No differences between study groups were seen in age, gender, body mass index, malnutrition, American Society of Anesthesiology class, time to liquid or regular diet, 30-d or inhospital mortality, or rates of complications. Patients undergoing blowhole colostomy had significantly higher cecal diameters at diagnosis (9.14 versus 7.31 cm, P = 0.0035). Operative time was shorter in blowhole procedures (43 versus 51 min, P = 0.017). Postoperative length of stay was significantly shorter for blowhole colostomy (6 versus 8 d, P = 0.014). The primary endpoint of successful colonic decompression was met in all colostomy patients.

Conclusions

Diverting blowhole colostomy is a safe, quick, and effective procedure for the urgent management of distal colonic obstruction associated with obstipation and massive distention.     

Outcome and safety of self-expandable metallic stents for malignant colon obstruction: a Korean multicenter randomized prospective study

Background

Newly developed uncovered stents are designed to have varied radial force and high conformability to improve clinical outcome and safety. This study aimed to determine and compare the clinical outcome and safety of the Taewoong D-type uncovered stent and the Boston Scientific Wallfex stent.

Methods

Patients with acute malignant colonic obstruction were treated with a colonic stent. For the purpose of palliation, patients were randomly allocated. For the purpose of bridging, the type of stent was determined by the discretion of the individual doctors. Technical and clinical success and complication occurrence were measured as primary outcomes.

Results

From 12 university hospitals, 123 patients with malignant colonic obstruction were enrolled. Of these 123 patients, 58 were treated with colonic stents for palliative purposes. The technical and clinical success rate was 100?% for both stents in the palliative group. Perforation occurred for one patient (3.6?%) in the Wallflex stent group (n?=?28) on day 5 and for no patients in the D-type stent group (n?=?30). Two cases of migration occurred: one with the Wallflex stent and one with the D-type stent. Stent restenosis occurred for one patient with the Wallflex stent. Preoperative bridging stents were placed in 65 patients. The median time to surgery was 10?days. The technical success rate was 93.4?%, and clinical success was achieved for 86.2?% of the patients. Perforation occurred for five patients: four with the Wallflex stent and one with the D-type stent. The efficacy and safety of the two stents did not differ statistically.

Conclusions

The D-type colonic uncovered stent and the Wallflex colonic uncovered stent are effective and safe for both palliative and preoperative bridging therapy used to treat acute malignant colonic obstruction.     

Ureteral stenting in laparoscopic colorectal surgery

Background

Few studies have examined the current status of ureteral stent use or the indications for stenting, particularly in laparoscopic colorectal surgery. This study examines current national trends and predictors of ureteral stenting in patients undergoing major colorectal operations and the subsequent effects on perioperative outcomes.

Methods

The 2005–2011 National Surgical Quality Improvement participant user files were used to identify patients undergoing laparoscopic segmental colectomy, low anterior resection, or proctectomy. Trends in stent use were assessed across procedure types. To estimate the predictors of stent utilization, a forward-stepwise logistic regression model was used. A 3:1 nearest neighbor propensity match with subsequent multivariable adjustment was then used to estimate the impact of stents.

Results

A total of 42,311 cases were identified, of which 1795 (4.2%) underwent ureteral stent placement. Predictors of stent utilization included diverticular disease, need for radical resection (versus segmental colectomy), recent radiotherapy, and more recent calendar year. After adjustment, ureteral stenting appeared to be associated with a small increase in median operative time (44 min) and a trivial increase in length of stay (5.4%, P < 0.001). However, there were no significant differences in morbidity or mortality.

Conclusions

We describe the clinical predictors of ureteral stent usage in this patient population and report that while stenting adds to operative time, it is not associated with significantly increased morbidity or mortality after adjusting for diagnosis and comorbidities. Focused institutional studies are necessary in the future to address the utility of ureteral stents in the identification and possible prevention of iatrogenic injury.     

The first use of Resonance® metallic ureteric stent in a case of obstructed transplant kidney

INTRODUCTION

To date, double JJ stent is the mainstay ureteric stent used in a transplant kidney. We herein report the first use of Resonance^® metallic ureteric stent to manage ureteric obstruction in a transplant kidney.

PRESENTATION OF CASE

A 45-year-old lady underwent an uneventful living related donor renal transplantation. Due to post-operative pelvi-ureteric obstruction and recurrent obstruction following multiple distal stent migration and expulsion necessitated frequent nephrostomy insertion and antegrade stenting, she underwent challenging but successful retrograde insertion of a 12 centimetres long and size 6.0 French Cook Resonance^® metallic ureteric stent which was performed under general anaesthesia.

DISCUSSION

Metallic ureteric stents are a fairly recent introduction to modern urology and they have been successfully used in the management of benign and malignant obstruction of ureter.

CONCLUSION

This is the first case of therapeutic metallic ureteric stent insertion in a transplant kidney.     

Outcomes of indwelling metallic stents for malignant extrinsic ureteral obstruction

Objectives

To report the treatment outcomes of patients with extrinsic ureteral obstruction treated with metallic stents and to identify the factors predicting stent failure.

Methods

A total of 52 patients with extrinsic ureteral obstruction as a result of malignancy (66 ureters) were treated with metallic stents (Resonance^®) and included in the study. The median observation period was 118 days.

Results

The median survival time of these patients was 210 days, and the stent patency rate was 86.0% at 6 months and 60.0% at 1 year. Eight (15.4%) patients underwent nephrostomy as a result of stent failure. The occlusion rate of bilateral ureteral obstructed cases was significantly higher than that of unilateral cases. There was no correlation between the preoperative serum creatinine level, causes of ureteral occlusions (compression by tumor, lymph node metastasis, peritoneal dissemination), obstructed site (upper, middle, lower ureter) and stent failure.

Conclusions

Metallic stents are excellent in maintaining patency compared with the conventional stents. Therefore, they can be used as first‐line treatment of malignant ureteral obstructions.     

Overuse of fluoroscopic gastrostomy studies in a children's hospital

Background

Gastrostomy tubes are often dislodged or exchanged in children. Indications for fluoroscopic examination of gastrostomy location include concern for malposition, dislodgement, leak, or gastric outlet obstruction. We hypothesized that most of the studies obtained at our institution were not ordered for one of the aforementioned indications and do not ultimately affect patient management.

Methods

All fluoroscopic gastrostomy studies performed from January 2011 to December 2012 were reviewed. Transgastric jejunostomy studies were excluded. Patient demographics, indications for the study, elapsed time since placement, imaging findings, and short-term outcomes were recorded. Chi-square analysis was used to evaluate relationships between categorical variables.

Results

During the study period, 337 patients who underwent fluoroscopic gastrostomy studies were identified; median age was 2.5 y (0.05–23.8). Sixty-two percent (208/337) of the studies were ordered in asymptomatic patients to confirm tube placement location after routine exchange or replacement. Symptomatic patients accounted for 38% of the studies. Ordering physicians were primarily nonsurgeons (72%, 242/337). Abnormal findings were observed in 4.8% (16/337) of patients, six (1.7%) of whom required an operative intervention. The 2.9% (6/208) abnormal study rate for asymptomatic patients was significantly lower than the 7.9% (10/129) rate in the patients who were evaluated for symptomatic indications (P = 0.03).

Conclusions

Most of the fluoroscopic gastrostomy studies ordered at a tertiary care center did not appear to alter patient care. Development of a standardized management algorithm based on clinical indications is necessary to decrease the number of extraneous gastrostomy studies.     

The incidence and risk factors of gastrointestinal complications after hepatectomy: a retrospective observational study of 1329 consecutive patients in a single center

Background

Despite of the importance of gastrointestinal (GI) complications in morbidity and mortality after major and moderate surgeries, it is not yet specifically studied in patients undergoing hepatectomy. This study was aimed to investigate the in-hospital incidence and potential risk factors of GI complications after open hepatectomy in our hospital.

Subjects and methods

Prospectively recorded perioperative data from 1329 patients undergoing elective hepatectomy were retrospectively reviewed. The in-hospital incidence of GI complications was investigated, and independent risk factors were analyzed by multiple logistic regression.

Results

GI complications occurrence was 46.4%. Univariate analysis showed that preoperative Child-Pugh score, total bilirubin, aspartate transaminase, anesthesia duration, operation duration, intraoperative blood loss, crystalloid and colloid infusion, blood transfusion, urine output, use of Pringle maneuver were statistically different between patients with and without GI complications (P < 0.05). Moreover, patients with GI complications had a more prolonged postoperative parenteral nutrient supporting time, hospital stay and ICU stay, and higher incidence of other complications than those without GI complications (P < 0.05). Multivariate regression indicated that long duration of anesthesia (odds ratio 2.51, P < 0.001) and use of Pringle maneuver (odds ratio 1.37, P = 0.007) were independent risk factors of GI complications after hepatectomy.

Conclusions

The incidence of GI complications after hepatectomy is high, which is related to an increase of other complications and a prolonged hospital stay. Avoidance of routinely use of Pringle maneuver and shortening the duration of anesthesia are important measures to reduce the postoperative GI complications.     

Palliation of malignant gastric outlet obstruction with simultaneous endoscopic insertion of afferent and efferent jejunal limb enteral stents in patients with recurrent malignancy

Background

Patients with prior pancreaticobiliary or distal gastric cancer treated surgically may have local anastomotic recurrence with obstruction of the afferent and efferent jejunal limbs. This report describes the efficacy and safety of simultaneous endoscopic insertion of self-expanding metal stents into the afferent and efferent jejunal limbs in patients with gastric outlet obstruction (GOO) of post-surgical anatomy for palliation of recurrent malignancy.

Methods

Patients were identified from an endoscopic database at a specialized cancer center between September 2007 and March 2014. Technical success was defined as single-session insertion of afferent and efferent jejunal limb enteral stents. Clinical success was defined as immediate symptom relief and ability to advance diet. A durable response was defined as symptom relief of at least 60 days or until hospice placement or death.

Results

Twenty-three patients were identified who underwent insertion of two 22-mm-diameter uncovered duodenal stents. Stent length varied from 60 to 120 mm. Stents were placed under endoscopic and fluoroscopic guidance. Three patients required balloon dilation to facilitate stent insertion. Average procedure time was 58.8 min (range 28–120). Technical success was achieved in 23/24 (96 %) patients. Clinical success was achieved in 19/23 (83 %) patients. Following initial stent insertion and prior to subsequent re-intervention, 11/19 (58 %) patients had a durable response with a median duration of 70 days (range 4–315). Eight (42 %) patients underwent subsequent re-intervention at a median of 22 days (range 11–315). Five patients had stent revision and were able to tolerate oral intake. Two patients had percutaneous endoscopic gastrostomy/jejunostomy insertion. One patient required surgical diversion for persistent obstruction. Complications included stent migration and post-stent insertion bacteremia due to food bolus obstruction.

Conclusions

Recurrent malignant GOO in patients with post-surgical anatomy treated with simultaneous endoscopic enteral stenting of afferent and efferent jejunal limbs has a high rate of technical and clinical success and low rate of complications and provides effective palliation.

     

Treatment of anastomotic stenosis and leakage after colorectal resection for cancer with self-expandable metal stents

Background

Self-expandable metallic stents can be used to treat patients with symptomatic anastomotic complications after colorectal resection.

Methods

Twenty patients with symptomatic anastomotic stricture after colorectal resection were treated with endoscopic placement of a self-expandable metal stent. Ten patients had “simple” anastomotic stricture. In the remaining 10 patients, a leak was associated with the stricture.

Results

The anastomotic leakage healed without evidence of residual stricture or major fecal incontinence in 8 of 10 patients. Overall, the anastomotic stricture was resolved in 14 of the 20 patients.

Conclusions

Self-expandable metal stents represent a valid adjunctive to treat patients with symptomatic anastomotic complications after colorectal resection for cancer. They have a complementary role to balloon dilatation in case of simple anastomotic stricture, and they improve the rate of healing when the stricture is associated with a leak.     

Coronary angiography and failure to rescue after postoperative myocardial infarction in patients with coronary stents undergoing noncardiac surgery

Background

We evaluated coronary angiography use among patients with coronary stents suffering postoperative myocardial infarction (MI) and the association with mortality.

Methods

Patients with prior coronary stenting who underwent inpatient noncardiac surgery in Veterans Affairs hospitals between 2000 and 2012 and experienced postoperative MI were identified. Predictors of 30-day post-MI mortality were evaluated.

Results

Following 12,096 operations, 353 (2.9%) patients had postoperative MI and 58 (16.4%) died. Post-MI coronary angiography was performed in 103 (29.2%) patients. Coronary angiography was not associated with 30-day mortality (odds ratio [OR]: .70, 95% CI: .35–1.42). Instead, 30-day mortality was predicted by revised cardiac risk index ≥3 (OR 1.91, 95% CI: 1.04–3.50) and prior bare metal stent (OR 2.12, 95% CI: 1.04–4.33).

Conclusions

Less than one-third of patients with coronary stents suffering postoperative MI underwent coronary angiography. Significant predictors of mortality were higher revised cardiac risk index and prior bare metal stent. These findings highlight the importance of comorbidities in predicting mortality following postoperative MI.     

Long-term result of Memokath urethral sphincter stent in spinal cord injury patients

Background

Memokath urethral sphincter stents are used to facilitate bladder emptying in patients with spinal cord injury, but long term follow-up has not been reported.

Methods

Case series of ten men with spinal cord injury who underwent insertion of Memokath stents and were followed for up to nine years.

Results

Within four years, the stent had to be removed in nine out of ten patients because of: extensive mucosal proliferation causing obstruction to the lumen of the stent; stone around the proximal end of the stent, incomplete bladder emptying, and recurrent urinary infections; migration of the stent into the bladder related to digital evacuation of bowels; large residual urine; concretions within the stent causing obstruction to flow of urine, and partial blockage of the stent causing frequent episodes of autonomic dysreflexia. In one patient the stent continued to function satisfactorily after nine years.

Conclusions

The Memokath stent has a role as a temporary measure for treatment of detrusor-sphincter dyssynergia in selected SCI patients who do not get recurrent urinary infection and do not require manual evacuation of bowels.

     

Stabilization of multiple rib fractures in a canine model

Background

Operative stabilization is frequently used in the clinical treatment of multiple rib fractures (MRF); however, no ideal material exists for use in this fixation. This study investigates a newly developed biodegradable plate system for the stabilization of MRF.

Methods

Silk fiber-reinforced polycaprolactone (SF/PCL) plates were developed for rib fracture stabilization and studied using a canine flail chest model. Adult mongrel dogs were divided into three groups: one group received the SF/PCL plates, one group received standard clinical steel plates, and the final group did not undergo operative fracture stabilization (n = 6 for each group). Radiographic, mechanical, and histologic examination was performed to evaluate the effectiveness of the biodegradable material for the stabilization of the rib fractures.

Results

No nonunion and no infections were found when using SF-PCL plates. The fracture sites collapsed in the untreated control group, leading to obvious chest wall deformity not encountered in the two groups that underwent operative stabilization.

Conclusions

Our experimental study shows that the SF/PCL plate has the biocompatibility and mechanical strength suitable for fixation of MRF and is potentially ideal for the treatment of these injuries.     

An evaluation of three-dimensional image–guided technologies in percutaneous pelvic and acetabular lag screw placement

Background

Percutaneous stabilization using three-dimensional (3D) navigation system is a promising treatment for pelvic and acetabular fractures. However, there are still some controversies regarding the use of 3D navigation to treat pelvic and acetabular fractures. The purpose of this study was to compare the Iso-C^3D fluoroscopic navigation, standard fluoroscopy, and two-dimensional (2D) fluoroscopic navigation in placing percutaneous lag screws in pelvic specimens to better understand the merits of 3D navigation techniques.

Methods

Fifty-four instrumentation procedures were performed in this study using six cadaveric pelvic specimens. Three groups were designated for different procedures and tests: group I, standard fluoroscopy; group II, 2D fluoroscopic navigation; and group III, Iso-C^3D fluoroscopic navigation. Nine screws were placed in each pelvis, including four screws placed bilaterally through the ilium into S1 and S2 vertebrae, four screws placed bilaterally through anterior and posterior columns of acetabulum, and one screw placed through the pubic symphysis. 3D fluoroscopic techniques were evaluated to determine the accuracy of screw position, instrumentation time, and fluoroscopic time. The data were statistically analyzed using SPSS 13.0.

Results

The malposition rate was 38.89%, 22.22%, and 0% in standard fluoroscopy, 2D fluoroscopic navigation, and Iso-C^3D fluoroscopic navigation groups, respectively. There was no significant difference between standard fluoroscopy and 2D fluoroscopic navigation. Compared with Iso-C^3D fluoroscopic navigation, there were significant differences (analysis of variance [ANOVA], P < 0.05). The mean instrumentation operating time using Iso-C^3D fluoroscopic navigation technique was 15.4 ± 4.5 min. There were significant differences compared with standard fluoroscopy (31.5 ± 6.2 min) and 2D fluoroscopic navigation (26.3 ± 7.5 min; ANOVA, post hoc Scheffe, P < 0.01). The mean fluoroscopic time of Iso-C^3D fluoroscopic navigation was 66 ± 4.8 min. Compared with standard fluoroscopy (132.8 ± 7.3 min) and 2D fluoroscopic navigation (47.7 ± 5.6 min), there were significant differences (ANOVA, post hoc least significant difference, P < 0.01).

Conclusions

In the present study, we compared Iso-C^3D fluoroscopic navigation, 2D fluoroscopic navigation, and standard fluoroscopy. Iso-C^3D fluoroscopic navigation showed a higher accuracy rate in positioning and a shorter instrumentation operating time. The fluoroscopic time was longer in Iso-C^3D fluoroscopic navigation than that in standard fluoroscopy, indicating that radiation exposure can be moderately reduced in Iso-C^3D fluoroscopic navigation operation, although the fluoroscopic time was the shortest in 2D fluoroscopic navigation.