Injectable biomaterials for incontinence and vesico-ureteral reflux: current status and future promise

Inflammatory complications of vocal fold injection with hyaluronic acid: a multiinstitutional study

Background/aim

This study aimed to assess the inflammatory adverse reactions of vocal fold injection laryngoplasty with hyaluronic acid.

Materials and methods

This study was a retrospective chart review of patients who underwent vocal fold injection augmentation with HA injection from January 2005 to September 2016 in nine different institutions. Demographic data, indication for injection, injection techniques, types of injection material, settings of procedure, and complications were reviewed. The types of complication, onset time, and management of complications were also noted.

Results

In all, 467 patients were identified. The majority of patients had been injected under general anesthesia (n = 382, 84.7%). For injection material, two different types of hyaluronic acid were used: hyaluronic acid alone or hyaluronic acid with dextranomer. Complications occurred in nine patients (1.9%). The majority of complications were inflammatory reactions (n = 7, 1.47%). Main symptoms were dysphonia and/or dyspnea with an onset of 0 h to 3 weeks after the hyaluronic acid injection. Three patients were hospitalized, one of which was also intubated and observed in the intensive care unit for 24 h. Systemic steroids and antibiotics were the main medical treatment in the majority of cases. There was no statistical difference in complication rates between patients who received hyaluronic acid and those who received hyaluronic acid with dextranomer (P = 0.220).

Conclusion

Hyaluronic acid can be considered as a safe substance for the injection of vocal folds with a low risk of inflammatory reaction.

Can magnetic resonance imaging differentiate among transurethral bulking agent, urethral diverticulum, and periurethral cyst?

PURPOSE

To evaluate magnetic resonance imaging findings that differentiate among periurethral bulking agents (primarily collagen), urethral diverticulum, and periurethral cyst.

METHODS

We searched our radiologic database retrospectively from 2001 to 2017 for periurethral cystic lesions, identifying a total of 50 patients with 68 lesions. Final diagnoses in 68 lesions were bulking agents (27), urethral diverticula (29), and periurethral cysts (12). Two abdominal radiologists, blinded to clinical history, independently evaluated T1, T2, and post-contrast images. The readers assessed number, morphological features, location, connection to urethra and mass effect, signal intensity, and enhancement for each lesion. Fisher exact test and logistic regression analysis were performed for each univariate significant feature. The operative and pathologic reports were the reference standard.

RESULTS

Magnetic resonance imaging features found more often in bulking agents versus urethral diverticulum were multiple lesions (P = 0.011), upper or upper-mid-urethral location (P ≤ 0.0001), lack of internal fluid/fluid level (P = 0.002), no urethral connection (P = 0.005), T1 isointensity, and T2 mild hyperintensity compared to muscles but lower T2 signal than urine (P < 0.0001). Most cases of urethral diverticula and periurethral cysts were detected at mid- and lower urethra. Urethral diverticula were larger than bulking agents and periurethral cysts (P = 0.005 and P = 0.023) (mean diameter = 24, 16, 15 mm, respectively). Most bulking agents (93%) and urethral diverticula (90%) showed mass effect on urethra, while periurethral cysts (75%) did not (P < 0.0001).

CONCLUSION

Signal intensity and lesion characterization on magnetic resonance imaging can significantly differentiate bulking agent from urethral diverticulum and periurethral cyst. Radiologists should consider differential diagnosis of a bulking agent, especially when distinguishing characteristics described here are present to prevent incorrect diagnosis and ultimately unnecessary surgical intervention.

Novel Bioceramic Urethral Bulking Agents Elicit Improved Host Tissue Responses in a Rat Model

Objectives. To test the physical properties and host response to the bioceramic particles, silica-calcium phosphate (SCPC10) and Cristobalite, in a rat animal model and compare their biocompatibility to the current clinically utilized urethral bulking materials. Material and Methods. The novel bulking materials, SCPC10 and Cristobalite, were suspended in hyaluronic acid sodium salt and injected into the mid urethra of a rat. Additional animals were injected with bulking materials currently in clinical use. Physiological response was assessed using voiding trials, and host tissue response was evaluated using hard tissue histology and immunohistochemical analysis. Distant organs were evaluated for the presence of particles or their components. Results. Histological analysis of the urethral tissue five months after injection showed that both SCPC10 and Cristobalite induced a more robust fibroblastic and histiocytic reaction, promoting integration and encapsulation of the particle aggregates, leading to a larger bulking effect. Concentrations of Ca, Na, Si, and P ions in the experimental groups were comparable to control animals. Conclusions. This side-by-side examination of urethral bulking agents using a rat animal model and hard tissue histology techniques compared two newly developed bioactive ceramic particles to three of the currently used bulking agents. The local host tissue response and bulking effects of bioceramic particles were superior while also possessing a comparable safety profile.

Endoscopic treatment of grades IV and V vesicoureteral reflux with two bulking substances: Dextranomer hyaluronic acid copolymer versus polyacrylate polyalcohol copolymer in children

PURPOSE

We aimed at evaluating the efficacy and complications of two bulking substances: dextranomer/hyaluronic acid copolymer(Dx/Ha;Dexell®) versus polyacrylate polyalcohol copolymer(PPC;Vantris®) in subureteric injection treatment of children with high grades (grades IV-V) vesicoureteral reflux(VUR).

METHODS

Data of patients undergoing endoscopic treatment of high grade VUR (January 2009-August 2015) were retrospectively investigated. Patients with high grade VUR caused by posterior urethral valve, duplex system, paraureteral diverticula and neurogenic bladder were excluded. Classical subureteric injection method (STING) was used. Seventy-three children (45 girls and 28 boys) who had 88 refluxing renal units (RRUs) with grades IV-V VUR (n=64/n=24) underwent endoscopic treatment using Dx/Ha (n=63 RRUs) and PPC (n=25 RRUs).

RESULTS

Mean age of patients in Dx/Ha and PPC groups were 6 (3) and 6 (3.75) year (p=0.81), and volumes of these substances given were 1.3 (1) and 1 (0.5) mL (p=0.003), respectively. Overall, for the first endoscopic injection, success rate of grades IV-V VUR per RRU was 53.9% with Dx/Ha, compared to 80% in PPC-injected group, (p=0.024). Late ureterovesical junction obstruction developed only in one patient in PPC-injected group. No ureteral obstruction was observed in Dx/Ha-injected group.

CONCLUSIONS

Endoscopic injection of PPC resulted in significantly higher success rate, compared to Dx/Ha in subureteric injection treatment of children with high grade VUR. However, the development of late ureterovesical junction obstruction should also be taken into account in PPC injection.

Autologous adipocyte graft in endoscopic treatment of vesico-renal reflux in children: a preliminary study

No bulking agent is ideal for endoscopically treating vesico-renal reflux in children. Many teams have tried to find a safe and efficient material, ideally an autologous material. We describe here a protocol for the use of autologous viable fat in the treatment of primary vesico-renal reflux in children aged from 3 to 15 years. Fat harvesting was done from the medial side of the thigh by manual aspiration. Samples were centrifuged to purify the graft from blood and lipid. Lastly fat was injected beneath the pathologic ureter by a conventional endoscopic technique. A voiding cystourethrography (VCUG) closed the procedure. Follow-up included renal ultrasonography the day after surgery, and one and three months later. A VCUG was performed systematically at three months and, in cases of acute pyelonephritis, during the survey.Sixty-four children with 94 refluxing units were treated by autologous fat injection with a follow-up from 6 to 40 months. At the end of the procedure, we systematically obtained a very good increase in height of the pathologic meatus and VCUG was normal in all cases. None presented with an obstruction during the follow-up period. Two children presented with an acute pyelonephritis before the third month. At three months, VCUG was not realized in 14 cases (22%) because the parents refused the procedure. One of those children presented with an acute pyelonephritis five months after endoscopic treatment. VCUG was normal for 17 of 50 children (34%), and showed a real improvement for 19 other children (38%). Three children had a surgical reimplantation because of the persistence of an unchanged high-grade vesico-renal reflux; histological examination found viable adipocytes on sections of the distal pathologic ureter. Clinically, 11 children (17%) presented with an acute pyelonephritis after treatment at a mean follow-up time of 10 months.These preliminary findings led us to modify the technique in order to improve our results. Our first concern is feasibility and safety of this technique, regardless of the use of other synthetic bulking agents the innocuousness of which is uncertain.

Complications of ethylene vinyl alcohol copolymer as an intraurethral bulking agent in men with stress urinary incontinence

OBJECTIVES

To report the short-term safety and efficacy of ethylene vinyl alcohol (EVA) copolymer (Tegress; C.R. Bard, Inc., Covington, GA) in the off-label treatment of male stress urinary incontinence.

METHODS

We reviewed the charts of all adult male patients who received EVA copolymer between 2005 and 2006 for demographics, physical examination findings, urodynamic findings, outcomes, and complications.

RESULTS

A total of 17 of 18 men completed follow-up after receiving EVA during this time period. With an average of 1.4 injection sessions, 58.8% of patients experienced a complication related to the procedure, with 41.1% of these complications being urethral erosion of the material and 22% experiencing severe pain on injection. Subjective improvement of at least 50% was reported by 41.1% of patients. The mean follow-up period was 4.2 months.

CONCLUSIONS

Intraurethral bulking agents are meant to be a minimally invasive procedure with lower complication rates than alternatives such as the artificial urinary sphincter and male sling. The off-label use of EVA in men in this case series resulted in a significant complication rate. Urethral erosion was the most common complication causing dysuria, precluding further bulking in others, and resulting in loss of benefit with passage of material. In addition, EVA used in men may be less efficacious than the Food and Drug Administration data reported in women, especially with prior injectable therapy. In December 2006, EVA was voluntarily taken off the marketplace by CR Bard owing to reports from clinicians.

Adjustable Continence Therapy (ProACT™): Evolution of the Surgical Technique and Comparison of the Original 50 Patients with the Most Recent 50 Patients at a Single Centre

OBJECTIVES

The desire for an adjustable surgery for male stress urinary incontinence that avoids further surgery has produced a percutaneous adjustable device. The adjustable continence therapy (ProACT) consists of two balloons, placed bilaterally at the bladder neck after prostatectomy. Titanium ports, attached via tubing to each balloon are placed in the scrotum allowing for volume adjustments of the balloons at any time perioperatively and postoperatively. This paper examines the evolution of the technique and the impact of this progression on patient outcomes.

METHODS

Two groups, one representing the first 50 patients, the second consisting of the last 50 patients are compared for changes in pad use and incontinence quality of life (I-QOL) with a mean follow-up of 23 mo (range: 1-46 mo) in group 1 and 20 mo (range: 18-24) in group 2. A comparison of complications and retreatment is summarised.

RESULTS

Pad usage was reduced significantly in both groups (p<0.001). Overall, group 2 patients obtained more consistent outcomes compared to group 1 (80% vs. 60% dry or >50% improved). I-QOL improved in both groups although more significantly in group 2 (p = 0.005). Operative time was reduced in group 2. The rate and range of complications experienced in group 1 as the technique evolved decreased dramatically in group 2.

CONCLUSIONS

The evolution of technique and expertise has facilitated an efficient surgical implantation procedure with reproducible and effective objective and subjective outcomes. The implantation of this device is now conducted in >100 centres across Europe.

The safety and efficacy of ethylene vinyl alcohol copolymer as an intra-urethral bulking agent in women with intrinsic urethral deficiency

The purpose of this post-marketing case-series is to report the short-term safety and effectiveness of ethylene vinyl alcohol (EVA) copolymer (Tegress; C.R. Bard, Covington, GA, USA) in the treatment of intrinsic sphincter deficiency (ISD). The charts of all female patients who received ethylene vinyl alcohol (EVA) copolymer between 2005 and 2006 were reviewed for demographics, physical exam, urodynamic findings, outcomes and complications. Nineteen of twenty women who received EVA during this period completed follow-up. After an average of 1.4 injections, approximately 58% of the patients had a complication related to the procedure with 37% experiencing urethral erosion. Of the patients, 10.5% reported at least a 50% subjective improvement in their symptoms. Intra-urethral bulking for the treatment of SID is meant to be minimally invasive and safe with minimal reports of complications. This series of 19 patients show significant percentage of patients experiencing serious complications with Tegress. Additionally, Tegress may be less efficacious than reported in the FDA trials, especially those with prior injections. A long-term prospective study needs to be performed in women with ISD before treatment can be recommended for general use by all gynecologists and urologists.