Mechanical Failure Rate Research Articles

Management of the Inflatable Penile Prosthesis Reservoir at time of revision surgery: remove, retain, or recycle?

Abstract Background Three common strategies exist for managing the inflatable penile prosthesis reservoir during revision surgery: the original reservoir can be (a) removed, (b) deactivated and left in situ, sometimes referred to as “drain and retain” (DR), or (c) validated and reconnected to new cylinders, which we have termed “reservoir recycling” (RR). Aim To compare the efficacy and safety of the RR approach to penile prosthesis revision against DR and the recommended approach of complete device removal and replacement. Methods A retrospective chart review of our single-surgeon inflatable penile prosthesis database between 2007 and 2022 was performed, identifying revision surgeries. Cases were stratified by reservoir management technique. Patients who had undergone at least 1 follow-up visit and had complete documentation regarding reservoir handling were included. Reservoir-related complications necessitating surgical intervention such as infection and device failure were compared between the 3 groups using a chi-square test. Mean follow-up duration, time to revision, and operative time were also assessed. Outcomes The primary outcome was the incidence of reservoir-related complications requiring surgical intervention and secondary outcomes included time to revision surgery and operative time. Results Among 140 patients meeting inclusion criteria, 62 underwent full reservoir replacement (FR), 48 DR, and 30 RR. Compared to FR, DR and RR groups had similar mean time to revision and intraoperative time. Follow-up duration was similarly limited for all 3 groups at a median of approximately 4.5 months. There were no postoperative infections in the RR cohort. However, when compared to the DR and FR groups, this did not reach significance (P = .398). There was no difference in mechanical failure rate between the 3 groups (P = .059). Nonmechanical failure was also similar between all 3 groups (P = .165). Clinical Implications These results suggest that RR exhibits comparable outcomes to DR and FR, making it a viable option during select penile prosthesis revision surgeries, potentially decreasing morbidity without compromising outcomes. Strengths and Limitations This is the first study to evaluate outcomes after RR. Limitations include small sample size, limited follow-up, and single-surgeon experience. Conclusion There was no difference in reservoir-related complications when comparing the 3 methods. These preliminary results suggest that reservoir recycling may provide a safe and effective reservoir-handling alternative in inflatable penile prosthesis revision surgery.

Anterior column realignment better restores sagittal alignment but carries higher risk of mechanical failures than lateral lumbar interbody fusion in patients with degenerative sagittal imbalance

Background of contextAnterior column realignment (ACR), a modified lateral lumbar interbody fusion (LLIF), is an emerging, less invasive technique that allows greater lordosis correction by releasing anterior longitudinal ligament. However, long-term results have been poorly documented with regard to mechanical failure, such as proximal junctional kyphosis (PJK) and rod fracture (RF), and clinical outcomes. PurposeTo compare the outcomes, primarily mechanical failure, in patients with degenerative sagittal imbalance (DSI) treated with ACR versus LLIF alone. Study design/settingRetrospective study Patient samplePatients ≥ 60 years of age; severe DSI defined by pelvic incidence (PI) - lumbar lordosis (LL) ≥ 20°; performance of ≥ 2-level LLIF; and ≥ 5 total fused levels including the sacrum. Outcome measuresMechanical failure such as PJK and RF; radiographic results; clinical outcomes MethodsEnrolled patients were divided into two groups, based on whether their anterior reconstruction was accomplished with ACR or LLIF alone: ACR and LLIF groups. Mechanical failures were compared between the two groups as a composite outcome including PJK and /or RF. PJK was defined as proximal junctional angle (PJA) >28° and Δ PJA >22°. Only RFs developing at the level with corresponding procedures (ACR or LLIF) were included in the analysis. Logistic regression was performed to compare the relative risk of mechanical failure between the ACR and LLIF groups. The radiographic and clinical outcomes were also compared between the groups. ResultsThe final study cohort consisted of 210 patients. The mean age was 69.6 years, and there were 190 females (90.5%). There were 124 patients in the ACR group and 86 patients in the LLIF group. Perioperative changes for all sagittal parameters were significantly greater in the ACR group than in the LLIF group. Overall mechanical failure rates were significantly higher in the ACR group than in the LLIF group (32.3% vs. 14.0%, P = 0.003). Multivariate regression analysis with adjusting potential confounders revealed that ACR carried a significantly higher risk of mechanical failure than LLIF (Odds ratio = 5.6, 95% confidence interval = 2.0 – 15.6, P < 0.001). The final clinical outcomes were worse in the ACR group than in the LLIF group. ConclusionACR restored the sagittal malalignment more powerfully than did LLIF. However, compared to the LLIF, ACR was associated with a greater risk of mechanical failures and revision surgery. The final clinical outcomes in the ACR group were inferior to those in the LLIF group. Therefore, ACR should be left as a last resort for the cases where it is expected that an adequate correction cannot be achieved using LLIF alone. If ACR has to be performed, it is necessary to establish feasible surgical strategies to avoid mechanical failures.

3D-Printed Prosthesis with an Articular Interface for Anatomical Acetabular Reconstruction After Type I + II (+ III) Internal Hemipelvectomy

Background: Pelvic reconstruction after type I + II (or type I + II + III) internal hemipelvectomy with extensive ilium removal is a great challenge. In an attempt to anatomically reconstruct the hip rotation center (HRC) and achieve a low mechanical failure rate, a custom-made, 3D-printed prosthesis with a porous articular interface was developed. The aim of this study was to investigate the clinical outcomes of patients treated with this prosthesis. Methods: This retrospective cohort study included 28 patients with type I + II (+ III) internal hemipelvectomy through the articular interface of the sacroiliac joint and managed with a prosthesis at a single center between August 2016 and August 2021. Complications and oncological outcomes were analyzed. The position of the reconstructed HRC was assessed and lower-limb function was evaluated. Biomechanical analyses of different fixation modes of the prosthesis were conducted using finite element analysis. Results: The displacement distance of the HRC from preoperatively to postoperatively was a mean (and standard deviation) of 14.12 ± 8.75 mm. The rate of implant-related complications was 14.3% (4 of 28) for prosthetic breakage, 14.3% (4 of 28) for aseptic loosening, 7.1% (2 of 28) for dislocation, and 7.1% (2 of 28) for deep infection. The mean Musculoskeletal Tumor Society (MSTS)-93 score was 18.2. The aseptic loosening rate was significantly greater for prostheses fixed with 3 sacral screws (4 of 10, 40.0%) than for those fixed with 4 (0 of 10, 0%) or 5 screws (0 of 8, 0%) (p = 0.024). The prosthetic breakage rate was lower in patients who underwent lumbosacral fixation (0 of 13, 0%) than in those who did not (4 of 15, 26.7%), although the difference did not reach significance (p = 0.102). Biomechanical analyses suggested that the addition of lumbosacral fixation or increasing the number of sacral screws from 3 to 4 or 5 visibly reduced the peak stress of the sacral screws. Conclusions: The use of a 3D-printed prosthesis with an articular interface for pelvic reconstruction demonstrated stable prosthetic fixation, anatomical acetabular reconstruction, and acceptable early functional outcomes. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Platelet-Rich Therapies in Hernia Repair: A Comprehensive Review of the Impact of Platelet Concentrates on Mesh Integration in Hernia Management.

Mesh-augmented hernia repair is the gold standard in abdominal wall and hiatal/diaphragmatic hernia management and ranks among the most common procedures performed by general surgeons. However, it is associated with a series of drawbacks, including recurrence, mesh infection, and adhesion formation. To address these weaknesses, numerous biomaterials have been investigated for mesh coating. Platelet-rich plasma (PRP) is an autologous agent that promotes tissue healing through numerous cytokines and growth factors. In addition, many reports highlight its contribution to better integration of different types of coated meshes, compared to conventional uncoated meshes. The use of PRP-coated meshes for hernia repair has been reported in the literature, but a review of technical aspects and outcomes is missing. The aim of this comprehensive review is to report the experimental studies investigating the synergistic use of PRP and mesh implants in hernia animal models. A comprehensive literature search was conducted across PubMed/Medline, Web of Science, and Scopus without chronological constraints. In total, fourteen experimental and three clinical studies have been included. Among experimental trials, synthetic, biologic, and composite meshes were used in four, nine, and one study, respectively. In synthetic meshes, PRP-coating leads to increased antioxidant levels and collaged deposition, reduced oxidative stress, and improved inflammatory response, while studies on biological meshes revealed increased neovascularization and tissue integration, reduced inflammation, adhesion severity, and mechanical failure rates. Finally, PRP-coating of composite meshes results in reduced adhesions and improved mechanical strength. Despite the abundance of preclinical data, there is a scarcity of clinical studies, mainly due to the absence of an established protocol regarding PRP preparation and application. To this point in time, PRP has been used as a coating agent for the repair of abdominal and diaphragmatic hernias, as well as for mesh fixation. Clinical application of conclusions drawn from experimental studies may lead to improved results in hernia repair.

Efficacy and safety of malleable penile prosthesis compared to inflatable penile prosthesis in erectile dysfunction patients.

Erectile dysfunction can cause self-withdrawal and decreased quality of life. Patients who do not respond to pharmacological therapy and other conservative treatments are urged to undergo penile prosthesis implantation. Malleable penile prosthesis was the first prosthesis developed, but then inflatable penile prosthesis was developed to give a more natural erection. There is no meta-analysis comparing inflatable and malleable penile prostheses in terms of safety and efficacy. This study is conducted to evaluate patient and partner satisfaction, ease of use, mechanical failure, and infection rate in patients who underwent penile prosthesis implantation. This meta-analysis followed Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) protocols. Five eligible studies were included from Pubmed, Scopus, ScienceDirect, and SemanticScholar databases. In this study, patient and partner satisfaction are significantly better (OR 3.39, 95% CI 1.66-6.93, p = 0.0008) (OR 2.32, 95% CI 1.75-3.08, p < 0.00001). Mechanical failure is also significantly higher in inflatable penile prostheses (OR 5.60, 95% CI 2.02-15.53, p = 0.0009). There is no significant difference in terms of ease of use and infection rate in inflatable or malleable penile prostheses. This study concluded that inflatable penile prosthesis is better in terms of patient and partner satisfaction, but mechanical failures occur more frequently in this type of prosthesis.

Outcomes of rotating versus pure hinge knee arthroplasty in the setting of one-stage exchange for periprosthetic joint infection.

Rotating or pure hinge knee prostheses are often used in case of periprosthetic joint infection (PJI). Five-year survival data of rotating hinge implants ranging from 52 to 90%, whereas pure hinge data are sparse. This study describes the results of both hinge knee prostheses after one-stage septic exchange. One hundred sixty-seven one-stage septic exchanges of a primary unconstrained total knee arthroplasty (TKA) to a cemented hinge prosthesis (117 rotating and 50 pure hinge TKAs) performed between 2008 and 2017 were retrospectively reviewed. Exclusion criteria were stem extensions or augments used in primary TKA, history of extensor mechanism reconstruction, and a follow-up less than twoyears after surgery. Rates of reinfection, mechanical failures, and all-cause revision-free survival data were documented. At fiveyears, the all-cause revision-free survival was 77% (95% CI 69 to 82). Thirty-one patients (19%) had further revision for aseptic reasons. In the rotating hinge group, the mechanical failure rate was more than twice as high as in the pure hinge group (13% vs 6%), significantly influenced by higher body weight. At a mean follow-up of 6.7years, 21 (13%) patients had a reinfection and underwent a further surgery. Reinfection rates did not differ between the two groups. The use of hinge TKA in the revision of PJI shows favourable fiveyear infection-free and all-cause revision-free survival rates of 91% and 77%, respectively. Our study showed poorer results of the rotating hinge design. These results may help surgeons to choose proper implants in case of septic knee revision.

141 Motor and Somatosensory Applications for Nerve Cuff Electrodes in Clinical Neuroprosthesis and Neurorehabilitation

INTRODUCTION: Surgically implanted neuroprosthetics aim to restore motor and somatosensory function by delivering controlled electrical impulses to paralyzed nerves. Recently, nerve cuff electrodes (NCEs) have been increasingly studied and may eventually offer the potential to recover somatomotor function in patients with neurologic injury. METHODS: The PubMed, Google Scholar, and Web of Science databases were searched to identify relevant articles published between 2012 – 2022 describing use of neuroprosthetic NCEs for clinical somatomotor rehabilitation. Data from all relevant articles retrieved were collected and summarized. RESULTS: NCE-neural interfaces can restore both upper and lower extremity motor function in spinal cord injury patients and may provide a treatment modality superior to that of muscle-based electrodes. The search yielded 137 studies, and of those reviewed, 18 were original research articles that used peripheral nerve stimulation to elicit motor actions and/or somatosensory perceptions through NCEs. 10 studies looked at restoring motor function in patients with spinal cord injuries or stroke-related paralysis and 7 studies looked at somatosensory applications of NCEs in patients with amputations. Currently, sensory NCE interfacing can restore and improve multiple aspects of sensation in amputees. While there is room for further study in various applications, technological improvements and wider clinical adoption, NCEs have been demonstrated to provide a clinically acceptable option in reducing intraoperative duration and morbidity, while preserving long-term functional stability, threshold charge maintenance, and acceptable mechanical failure rates. CONCLUSIONS: NCEs appear to be a promising avenue for future research in the field of neuroprosthetics. As the translational avenue continues to mature and more clinical studies become avaiable, the utility of NCEs will be better understood.

Incontinence Is an Independent Risk Factor for Total Hip and Knee Arthroplasty

BackgroundUrinary incontinence has been linked to worse postoperative pain, decreased physical function, and reduced quality of life in patients following total joint arthroplasty. The purpose of this study was to analyze whether incontinence is associated with increased postoperative medical and joint complications following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). MethodsA retrospective cohort study was conducted using a national insurance database. Thirty-two thousand eight hundred eleven patients with incontinence who underwent primary THA were identified and matched 1:4 with 129,073 patients without incontinence. Ninety-one thousand nine hundred thirty-five patients with incontinence who underwent primary TKA were matched 1:4 with 367,285 patients without incontinence. Medical and joint complication rates at 90 days and 2 years, respectively, were then compared for patient cohorts using multivariable logistic regressions. ResultsPatients who underwent primary THA with incontinence had statistically higher rates of dislocation, periprosthetic fracture, aseptic revisions, and overall joint complications compared to controls. Patients who underwent primary TKA with incontinence had higher rates of mechanical failure, aseptic revision, and all-cause revision compared to controls. ConclusionsThis study demonstrated an association between patients with incontinence and higher rates of dislocation, periprosthetic fractures, aseptic revisions, and overall joint complications following primary THA compared to controls. Patients with incontinence experience higher rates of mechanical failure, aseptic revision, and all-cause revision following TKA compared to controls. As such, perioperative management of urinary incontinence may help mitigate the risk of postoperative complications.

(161) Is there a Difference in Inflatable Penile Prosthesis Mechanical Failure and Infections Rates in Relation to Prostate Cancer Treatment Modality (Radiation Therapy vs Radical Prostatectomy)

Abstract Introduction Inflatable Penile Prosthesis (IPP) implantation as a treatment for ED has high satisfaction rates in the general population; however, there is limited literature on quantification of complication rates as stratified by ED etiology. Objective Our aim was to compare mechanical failure and infection rates in patients undergoing IPP implantation for ED following Radical Prostatectomy (RP) versus radiation therapy (RT) for prostate cancer. Methods A retrospective chart review from our institutional database was conducted to identify 405 patients who underwent IPP placement at our institution from 2015–2019, then selecting for those whose etiology of ED was following RP or RT. To prevent crossover confounding; patients with history of pelvic radiation or salvage radiotherapy were excluded from the RP group and patients with history of RP were excluded from the RT group. Data was obtained from 75 patients who met criteria for inclusion: 44 patients in the RP group and 31 patients in the RT group. Mechanical failure, infection rates, mean EDITS scores and additional survey questions were compared between the radiation and RP groups. Results Patient demographic information and IPP complication and satisfaction rates are listed below in Table 1 and Figure 1. There was a statistically significant difference in number of patients experiencing IPP complications, 19.4% (n=6) of patients in the RT cohort and 4.5% (n=2) in the RP cohort, respectively. There was no statistically significant difference found in stratified complications- infection rates, device erosion rates, mechanical failure rates, or device removal and/or replacement rates between the two groups. The RP cohort had a significantly higher mean Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) questionnaire score versus the RT cohort, 91.58 to 76.02, respectively. Conclusions These preliminary findings, while requiring large-scale follow up, suggest that there is a higher rate of IPP related complications in patients with device placement following RT for prostate cancer versus RP. Disclosure No.

(114) A Comparative Meta-Analysis of Revision Strategies for Malfunctioning Inflatable Penile Prosthesis: Partial vs Complete Component Replacement With or Without Retained Reservoir

Abstract Introduction In cases of non-infected malfunctioning Inflatable penile prosthesis (IPP) device, surgeon often opt to exchange all the device rather than the defective component for fear of increased infection rate and future mechanical dysfunction. Objective To assess whether partial component exchange of IPP device has comparable outcomes to complete explant and replacement of IPP device with or without retained reservoir. Methods A meta-analysis was completed in line with PRISMA 2020 and AMSTAR guidelines. A comprehensive search was done on MEDLINE (OVID), PubMed, and Cochrane Library electronic databases from their inceptions until May 2023, identifying studies that reported on outcomes and complications of revision surgery for non-infected malfunctioning IPP device. Three groups were compared: the first group underwent a single or two-component exchange, the second group had a complete explant replacement of the entire device, and the third group had replacement of all components with a drained and retained primary reservoir. Results A total of 9 articles were included in the analysis. 12,152 patients had complete replacement of their device, 128 had partial exchange of their device and 151 patients had “drained and retained” reservoir following revision. The mean age was similar among the 3 groups between 62–68 years. The median follows up time ranged between 12 and 79 months. Partial component ex change had a higher rate of mechanical failure 10.3% versus 1.3% and 2.3 % (p=0.03) for complete and “drain and retain” groups respectively. (Figure 1) Similarly, partial component exchange had higher peri-operative complications at 21.2% compared to complete replacement group 9.5% and “drain and retain” group 14.5% (p=0.022). However, the infection rate was similar among the three groups, 7.7%, 2.7% and 3.3% respectively (p= 0.301). (Figure 2) Conclusions Partial component exchange during IPP revision has higher rates of perioperative complication and future mechanical failure but has similar rate of infection compared to complete component replacement with or without “drain and retain” of original reservoir. Disclosure No.

(099) A Preliminary Investigation on the Incidence of Complications and Patient Contentment Following the Surgical Implantation of Inflatable Penile Prosthesis After Salvage Radical Prostatectomy

Abstract Introduction Erectile dysfunction (ED) is a common complication post salvage radical prostatectomy (RP). Yet, there is scant data in the literature on complication rates and patient satisfaction in those that undergo inflatable penile prosthesis (IPP) insertion post salvage radical prostatectomy (RP) following targeted radiotherapy for treatment of localized prostate cancer. It is understood that these patients have a higher rate of complications as they have experienced both radiation and prostatectomy adverse events which could alter their overall satisfaction after prosthetic surgeries. Objective Our aim is to conduct a preliminary analysis of IPP complication rates and satisfaction rates in patients that had 3-piece IPP implantation following salvage radical prostatectomy. Methods A retrospective chart review from our institutional database was done from 2018 to 2021. The inclusion criteria were patients that had an inserted 3-piece IPP and a history of salvage RP following radiation therapy. Only patients that participated Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) questionnaire at least 6 months from implant date were included. Data on satisfaction, IPP infection rates, mechanical failure rates, and overall complications was also collected. Complications include hematoma, erosion, reservoir hernia. Results A total of 22 patients were included in the study. The median age (IQR) is 65 (64–67) years and the median time (IQR) from RP to IPP insertion is 23 (11–49) months. All patients were approached in a penoscrotal manner with submuscular placement of reservoir (Table 1). The satisfaction rate was high at 91.8% on follow up. Overall complications rate was observed in 2 patients. One patient had a mechanical pump failure at 37.9 months while another patient had signs and symptoms of scrotal wall infection at 15 months. Both devices were easily replaced with no post op complication and remained functional on further follow up. Conclusions In patients that underwent salvage prostatectomy IPP insertion, they reported high satisfaction rates and low complication rates despite the exposure to both prostate cancer treatments adverse events. Further research is needed to confirm the results obtained and to investigate the underlying causes for the observed outcomes. The scientific process is iterative, and the answers obtained from one study often lead to more questions and the need for additional investigations. Disclosure No.

(391) A Comparative Meta-analysis of Revision Strategies for Malfunctioning Inflatable Penile Prosthesis: Partial Vs Complete Component Replacement With or Without Retained Reservoir

Abstract Introduction In cases of non-infected malfunctioning Inflatable penile prosthesis (IPP) device, surgeon often opt to exchange all the device rather than the defective component for fear of increased infection rate and future mechanical dysfunction. Objective To assess whether partial component exchange of IPP device has comparable outcomes to complete explant and replacement of IPP device with or without retained reservoir. Methods A meta-analysis was completed in line with PRISMA 2020 and AMSTAR guidelines. A comprehensive search was done on MEDLINE (OVID), PubMed, and Cochrane Library electronic databases from their inceptions until May 2023, identifying studies that reported on outcomes and complications of revision surgery for non-infected malfunctioning IPP device. Three groups were compared: the first group underwent a single or two-component exchange, the second group had a complete explant replacement of the entire device, and the third group had replacement of all components with a 'drained and retained' primary reservoir. Results A total of 9 articles were included in the analysis. 12,152 patients had complete replacement of their device, 128 had partial exchange of their device and 151 patients had “drained and retained” reservoir following revision. The mean age was similar among the 3 groups between 62-68 years. The median follow up time ranged between 12 and 79 months. Partial component exchange had a higher rates of mechanical failure 10.3% versus 1.3% and 2.3 % (p=0.03) for complete and “drain and retain” groups respectively. (Figure 1) Similarly, partial component exchange had higher perioperative complications at 21.2% compared to complete replacement group 9.5% and “drain and retain” group 14.5% (p=0.022). However, the infection rate was similar among the three groups, 7.7%, 2.7% and 3.3% respectively (p= 0.301). (Figure 2) Conclusions Partial component exchange during IPP revision has higher rates of perioperative complication and future mechanical failure but has similar rate of infection compared to complete component replacement with or without “drain and retain” of original reservoir. Disclosure No.

(284) A Preliminary Investigation on the Incidence of Complications and Patient Contentment Following the Surgical Implantation of Inflatable Penile Prosthesis After Salvage Radical Prostatectomy

Abstract Introduction Erectile dysfunction (ED) is a common complication post salvage radical prostatectomy (RP). Yet, there is scant data in the literature on complication rates and patient satisfaction in those that undergo inflatable penile prosthesis (IPP) insertion post salvage radical prostatectomy (RP) following targeted radiotherapy for treatment of localized prostate cancer. It is understood that these patients have a higher rate of complications as they have experienced both radiation and prostatectomy adverse events which could alter their overall satisfaction after prosthetic surgeries. Objective Our aim is to conduct a preliminary analysis of IPP complication rates and satisfaction rate in patients that had 3-piece IPP implantation following salvage radical prostatectomy. Methods A retrospective chart review from our institutional database was done from 2018 to 2021. The inclusion criteria were patients that had an inserted 3-piece IPP and a history of salvage RP following radiation therapy. Only patients that participated Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) questionnaire at least 6 months from implant date were included. Data on satisfaction, IPP infection rates, mechanical failure rates, and overall complications was also collected. Complications include hematoma, erosion, reservoir hernia. Results A total of 22 patients were included in the study. The median age (IQR) is 65 (64-67) years and the median time (IQR) from RP to IPP insertion is 23 (11-49) months. All patients were approached in a penoscrotal manner with submuscular placement of reservoir (Table 1). The satisfaction rate was high at 91.8% on follow up. Overall complications rate was observed in 2 patients. One patient had a mechanical pump failure at 37.9 months while another patient had signs and symptoms of scrotal wall infection at 15 months. Both devices were easily replaced with no post op complication and remained functional on further follow up. Conclusions In patients that underwent salvage prostatectomy IPP insertion, they reported high satisfaction rates and low complication rates despite the exposure to both prostate cancer treatments adverse events. Further research is needed to confirm the results obtained and to investigate the underlying causes for the observed outcomes. The scientific process is iterative, and the answers obtained from one study often lead to more questions and the need for additional investigations. Disclosure No.

Larger stem to bone diameter ratio predicts lower cemented endoprosthesis failure.

With continued advances in treatment options, patients with endoprosthetic reconstruction are living longer and consequently relying upon their devices for a longer duration. Major causes of endoprosthesis failure include aseptic loosening and mechanical failure. In the setting of tumor resection, loss of bone stock and use of radiation therapy increase the risk for these complications. As such, considerations of remaining native bone and stem length and diameter may be increasingly important. We asked the following questions: (1) What was the overall rate of endoprosthesis failure at a minimum of 5-year follow-up? (2) Does resection length increase implant failure rates? (3) Does implant size and its ratio to cortical width of bone alter implant failure rates? We retrospectively analyzed patient outcomes at a single institution between the years of 1999-2022 who underwent cemented endoprosthetic reconstruction at the hip or knee and identified 150 patients. Of these 150, 55had a follow-up of greater than 5 years and were used for analysis. Radiographs of these patients at time of surgery were assessed and measured for resection length, bone diameter, stem diameter, and remaining bone length. Resection percentage, and stem to bone diameter ratios were then calculated and their relationship to endoprosthesis failure were analyzed. Patients in this cohort had a mean age of 55.8, and mean follow-up of 59.96 months. There were 78 distal femoral replacements (52%), 16 proximal femoral replacements (10.7%), and 56 proximal tibial replacements (37.3%). There were five patients who experienced aseptic loosening and six patients who experienced mechanical failure. Patients with implant failure had a smaller mean stem to bone diameter (36% vs. 44%; p = 0.002). A stem to bone diameter of 40% appeared to be a breaking point between success and failure in this series, with 90% of patients with implant failure having a stem: bone ratio less than 40%. Stem to bone ratio less than 40% increased risk for failure versus stems that were at least 40% the diameter of bone (6/19 [31.6%] vs. 0/36 [0%]; odds ratio 0.68; p < 0.001). Resection length did not appear to have an impact on the rates of aseptic loosening and mechanical failure in this series. Data from this series suggests a benefit to using stems with a larger diameter when implanting cemented endoprostheses at the hip or knee. Stems which were less than 40% the diameter of bone were substantially more likely to undergo implant failure.

Posterolateral wall integrity in reverse oblique intertrochanteric fracture fixation: A new perspective in evaluation.

Treatment of reverse oblique fractures has the highest complication rate among proximal femur fractures. Although intramedullary nailing is the preferred treatment option, a high failure rate has been reported. Previous studies have identified several contributing factors to these failures, yet the significance of posterolateral wall integrity in ensuring postoperative stability has not been emphasized. This study aims to investigate the impact of posterolateral wall integrity on the failure rates of reverse oblique intertrochanteric fractures treated with intramedullary nails (IMN) and assess the vulnerability of certain IMN designs to these failures. Between 2010 and 2016, 53 patients with reverse oblique fractures were analyzed to identify factors associated with IMN failure. Variables such as posterolateral wall integrity, quality of reduction, posteromedial support, and IMN design were considered as potential risk factors. Logistic regression analysis was conducted to evaluate these risk factors, with statistical significance defined as p<0.05. Eleven cases of implant failure were identified. Univariate statistical analysis indicated that loss of posterolateral support (p=0.002), IMN with single-screw proximal fixation (p=0.048), poor reduction quality (p=0.004), and loss of posteromedial support (p=0.040) were associated with implant failure. Multivariate analysis confirmed loss of posterolateral support (p=0.009), poor reduction quality (p=0.039), and loss of posteromedial support (p=0.020) as independent risk factors for failure. However, IMN with single proximal fixation (p=0.859) did not significantly impact fixation failure. Reverse oblique intertrochanteric fractures with compromised posterolateral support exhibit a high rate of mechanical failure when treated with IMN. Additionally, poor reduction quality and loss of posteromedial support increase the risk for failure of these fractures. An IMN design featuring dual separate proximal screw fixations could provide better stability compared to a design with a single proximal screw, thereby reducing the risk of mechanical failure.

Effect of Cervicothoracic Junction LIV Selection on Posterior Cervical Fusion Mechanical Failure: A Systematic Review and Meta-Analysis.

Systematic review and Meta-analysis. Analyze and summarize literature evaluating the role of C7, T1, and T2 lowest instrumented vertebra (LIV) selection in posterior cervical fusion (PCF) and if this affects the progression of mechanical failure and revision surgery. Literature evaluating mechanical failure and adjacent segment disease in the setting of PCF at or nearby the cervicothoracic junction (CTJ) remains limited with studies reporting conflicting results. Two reviewers conducted a detailed systematic review using EMBASE, PubMed, Web of Science, and Google Scholar on June 28, 2021, for primary research articles comparing revision and complication rates for posterior fusions ending in the lower cervical spine (C7) and upper thoracic spine (T1-T2). The initial systematic database yielded 391 studies, of which 10 met all inclusion criteria. Random effects meta-analyses compared revision and mechanical failure rates between patients with an LIV above the CTJ and patients with an LIV below the CTJ. Data from 10 studies (total sample=2001, LIV above CTJ=1046, and LIV below CTJ=955) were meta-analyzed. No differences were found between the 2 cohorts for all-cause revision [odds ratio (OR)=0.75, 95% CI=0.42-1.34, P <0.0001] and construct-specific revision (OR=0.62, 95% CI=0.25-1.53, P <0.0001). The odds of total mechanical failure in the LIV below CTJ cohort compared with the LIV above CTJ cohort were significantly lower (OR=0.38, 95% CI=0.18-0.81, P <0.0001). The results show patients with PCFs ending below the CTJ have a lower risk of undergoing total mechanical failure compared with fusions ending above the CTJ. This is important information for both physicians and patients to consider when planning for operative treatment. Level I.

A novel artificial vertebral implant with Gyroid porous structures for reducing the subsidence and mechanical failure rate after vertebral body replacement

BackgroundProsthesis subsidence and mechanical failure were considered significant threats after vertebral body replacement during the long-term follow-up. Therefore, improving and optimizing the structure of vertebral substitutes for exceptional performance has become a pivotal challenge in spinal reconstruction.MethodsThe study aimed to develop a novel artificial vertebral implant (AVI) with triply periodic minimal surface Gyroid porous structures to enhance the safety and stability of prostheses. The biomechanical performance of AVIs under different loading conditions was analyzed using the finite element method. These implants were fabricated using selective laser melting technology and evaluated through static compression and subsidence experiments.ResultsThe results demonstrated that the peak stress in the Gyroid porous AVI was consistently lower than that in the traditional porous AVI under all loading conditions, with a maximum reduction of 73.4%. Additionally, it effectively reduced peak stress at the bone-implant interface of the vertebrae. Static compression experiments demonstrated that the Gyroid porous AVI was about 1.63 times to traditional porous AVI in terms of the maximum compression load, indicating that Gyroid porous AVI could meet the safety requirement. Furthermore, static subsidence experiments revealed that the subsidence tendency of Gyroid porous AVI in polyurethane foam (simulated cancellous bone) was approximately 15.7% lower than that of traditional porous AVI.ConclusionsThe Gyroid porous AVI exhibited higher compressive strength and lower subsidence tendency than the strut-based traditional porous AVI, indicating it may be a promising substitute for spinal reconstruction.

Radiographic outcomes following surgical correction for lumbar degenerative kyphosis: the impact of supine pelvic tilt.

Lumbar degenerative kyphosis (LDK), a flexible deformity, is a common form of sagittal imbalance in Asian countries. Assessing a patient's spine prior to surgery by using positional radiographs is becoming more crucial in determining surgical planning to achieve favorable clinical and radiographic outcomes, especially in patients with flexible deformities. This study aims to identify radiographic characteristics of supine pelvic tilt (sPT) and its relation to mechanical failure (MF) following LDK correction. A single-center, single-surgeon retrospective analysis was performed in patients who underwent LDK correction with sacropelvic fixation between January 2014 and May 2019. Patients were grouped into pelvic match and mismatch groups according to the difference between postoperative pelvic tilt (PT) and sPT. Demographic, surgical, and radiographic parameters were compared. Chronological change of PT was assessed by comparing preoperative, supine, immediate postoperative, and final PT. Baseline demographics and sagittal alignments were similar between PT match (n = 25) and mismatch (n = 42) groups (p > 0.05). There was a significant difference in the rate of MF between PT match and mismatch groups (4% vs 31%, p = 0.021). Multivariable analysis demonstrated that after including control variables, PT mismatch was independently associated with the likelihood of MF development (OR 33.42, p = 0.04). sPT reflects postoperative PT changes; therefore, supine imaging may represent a tool that could be used for preoperative decision-making in patients with LDK or possibly those with flexible adult spinal deformity. PT mismatch > 10° or < 0° is a significant risk factor for MF following correction of LDK. Measurement of sPT would aid surgeons in optimal preoperative planning and in minimizing catastrophic MF following deformity correction surgery.

A Completely Digital Workflow of an Interim Complete Arch Fixed Implant Prosthesis Using a Novel High-Performance 3D Printed Polymer

The advent of osseointegration has offered a quantum shift in treatment planning patients with missing teeth. Patients with a terminal dentition or edentulous arch have become candidates for a fixed rehabilitation with immediate function. A striking limitation of this modality, however, has been the mechanical failure rate of the reconstructions, especially the interim prostheses. This clinical report describes a completely digital workflow and additive manufacturing of an interim complete arch fixed implant prosthesis, immediately placed after extraction. The prosthesis is supported by four immediately loaded implants on the maxillary arch, using stackable guides and the use of a novel 3D printed high-performance UDMA to improve precision, efficiency, and prosthetic stability.

(498) Take it or Leave it? Comparison Between Drain and Retain Versus Reservoir Recycling in Inflatable Penile Prothesis Revision

Abstract Introduction There are three strategies for managing an implanted urologic reservoir during inflatable penile prothesis (IPP) revision. The original reservoir can be removed, deactivated and left in place (drain and retain), or validated and reconnected to an IPP system (reservoir recycling). Although complete removal of a reservoir would prevent the potential complications of a retained device, the formation of a surrounding fibrotic capsule leads to complete removal being less popular among providers compared to drain and retain or reservoir recycling. We sought to evaluate the long-term complications and efficacy of these approaches. Objective To compare the efficacy and safety of the drain and retain and reservoir recycle approaches to IPP revision against the gold standard of full device replacement. Methods We performed a retrospective chart review of our large, single-surgeon tertiary referral center penile prosthesis database between 2007-2022 to identify all individuals with a retained or recycled reservoir. Only those who had undergone appropriate follow-up and had complete documentation about reservoir handling were included in the study. Reservoir-related complications, mechanical failures, and device infections were compared between the retained, recycled, and full replacement groups using a chi-square test. Mean follow-up duration, time to revision, and operative time were assessed using a Student’s T-test. Results There were 140 patients who met inclusion criteria with 48 retained reservoirs, 30 recycled reservoirs, and 62 full replacements. The average age of a reservoir when it was recycled was 4.3 years. Retained and recycled reservoir groups had similar mean follow-up duration, time to revision, and intraoperative time when compared to the full replacement group (Table). Most reservoirs (91% of retained, 90% of recycled, 90% of full replacement) were implanted using the high submuscular technique. Our institution’s virgin IPP implant infection rate was 2.6%. When compared to the full replacement group, infection, mechanical failure, and revision rates were similar for both the retained and recycled reservoir groups (Table and Figure). There was only one verified post-revision reservoir leakage from a recycled reservoir, but no instances of reservoir herniation or reservoir-related bowel complications between the three groups. Conclusions There was no difference in reservoir-related complications, mechanical failure, or infections when comparing the drain and retain or reservoir recycle groups to the full replacement group. Reservoir drain and retain and recycling are both safe and effective management options in IPP revision surgery. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Boston Scientific, Coloplast.