Genitourinary complications in orthopaedic surgery.

Genitourinary complications following orthopaedic intervention are uncommon but well-described occurrences and exist on a spectrum of severity. These complications vary depending on the anatomic location and surgical approach, with surgery of the spine, hip, and pelvis of particular concern. Injuries to the urinary tract may present acutely with urinary retention or hematuria. However, they often have a delayed presentation with severe complications such as urinary fistula and recurrent infection. Delayed presentations may place the onus of timely and proper diagnosis on the orthopaedic provider, who may serve as the patient's primary source of long-term follow-up. Detailed knowledge of anatomy and at-risk structures is key to both preventing and identifying injury. Although iatrogenic injury is not always avoidable, early identification can help to facilitate timely evaluation and management to prevent long-term complications such as bladder dysfunction, obstructive renal injury, sexual dysfunction, and chronic pain.  Keywords: urologic injury, bladder injury, genitourinary injury, hip arthroplasty, pelvic ring injuries, spine surgery.

Combined in vivo and ex vivo analysis of mesh mechanics in a porcine hernia model.

BACKGROUND: Hernia meshes exhibit variability in mechanical properties, and their mechanical match to tissue has not been comprehensively studied. We used an innovative imaging model of in vivo strain tracking and ex vivo mechanical analysis to assess effects of mesh properties on repaired abdominal walls in a porcine model. We hypothesized that meshes with dissimilar mechanical properties compared to native tissue would alter abdominal wall mechanics more than better-matched meshes. METHODS: Seven mini-pigs underwent ventral hernia creation and subsequent open repair with one of two heavyweight polypropylene meshes. Following mesh implantation with attached radio-opaque beads, fluoroscopic images were taken at insufflation pressures from 5 to 30 mmHg on postoperative days 0, 7, and 28. At 28 days, animals were euthanized and ex vivo mechanical testing performed on full-thickness samples across repaired abdominal walls. Testing was conducted on 13 mini-pig controls, and on meshes separately. Stiffness and anisotropy (the ratio of stiffness in the transverse versus craniocaudal directions) were assessed. RESULTS: 3D reconstructions of repaired abdominal walls showed stretch patterns. As pressure increased, both meshes expanded, with no differences between groups. Over time, meshes contracted 17.65% (Mesh A) and 0.12% (Mesh B; p = 0.06). Mesh mechanics showed that Mesh A deviated from anisotropic native tissue more than Mesh B. Compared to native tissue, Mesh A was stiffer both transversely and craniocaudally. Explanted repaired abdominal walls of both treatment groups were stiffer than native tissue. Repaired tissue became less anisotropic over time, as mesh properties prevailed over native abdominal wall properties. CONCLUSIONS: This technique assessed 3D stretch at the mesh level in vivo in a porcine model. While the abdominal wall expanded, mesh-ingrown areas contracted, potentially indicating stresses at mesh edges. Ex vivo mechanics demonstrate that repaired tissue adopts mesh properties, suggesting that a better-matched mesh could reduce changes to abdominal wall mechanics.

Validation of Single C-Arm Fluoroscopic Technique for Measuring In Vivo Abdominal Wall Deformation.

Hernia meshes significantly reduce the recurrence rates in hernia repair. It is known that they affect the abdominal wall postimplantation, yet the understanding of in vivo mechanics in the mesh placement area is lacking. We established a single C-arm biplane fluoroscopic system to study strains at the interface between the mesh and repaired abdominal tissues. We aimed to validate this system for future porcine hernia repair studies. Custom matlab programs were written to correct for pincushion distortion, and direct linear transformation (DLT) reconstructed objects in 3D. Using a custom biplane-trough setup, image sets were acquired throughout the calibrated volume to evaluate a radio-opaque test piece with known distances between adjacent beads. Distances were measured postprocessing and compared to known measurements. Repeatability testing was conducted by taking image sets of the test piece in a fixed location to determine system movement. The error in areal stretch tracking was evaluated by imaging a square plate with fixed radio-opaque beads and using matlab programs to compare the measured areal stretch to known bead positions. Minor differences between measured and known distances in the test piece were not statistically different, and the system yielded a 0.01 mm bias in the XY plane and a precision of 0.61 mm. The measured areal stretch was 0.996, which was not significantly different than the expected value of 1. In addition, preliminary stretch data for a hernia mesh in a porcine model demonstrated technique feasibility to measure in vivo porcine abdominal mechanics.

Functionally Distinct Tendons From Elastin Haploinsufficient Mice Exhibit Mild Stiffening and Tendon-Specific Structural Alteration.

Elastic fibers are present in low quantities in tendon, where they are located both within fascicles near tenocytes and more broadly in the interfascicular matrix (IFM). While elastic fibers have long been known to be significant in the mechanics of elastin-rich tissue (i.e., vasculature, skin, lungs), recent studies have suggested a mechanical role for elastic fibers in tendons that is dependent on specific tendon function. However, the exact contribution of elastin to properties of different types of tendons (e.g., positional, energy-storing) remains unknown. Therefore, this study purposed to evaluate the role of elastin in the mechanical properties and collagen alignment of functionally distinct supraspinatus tendons (SSTs) and Achilles tendons (ATs) from elastin haploinsufficient (HET) and wild type (WT) mice. Despite the significant decrease in elastin in HET tendons, a slight increase in linear stiffness of both tendons was the only significant mechanical effect of elastin haploinsufficiency. Additionally, there were significant changes in collagen nanostructure and subtle alteration to collagen alignment in the AT but not the SST. Hence, elastin may play only a minor role in tendon mechanical properties. Alternatively, larger changes to tendon mechanics may have been mitigated by developmental compensation of HET tendons and/or the role of elastic fibers may be less prominent in smaller mouse tendons compared to the larger bovine and human tendons evaluated in previous studies. Further research will be necessary to fully elucidate the influence of various elastic fiber components on structure-function relationships in functionally distinct tendons.

Bioinspired Polarization Imaging Sensors: From Circuits and Optics to Signal Processing Algorithms and Biomedical Applications: Analysis at the focal plane emulates nature's method in sensors to image and diagnose with polarized light.

In this paper, we present recent work on bioinspired polarization imaging sensors and their applications in biomedicine. In particular, we focus on three different aspects of these sensors. First, we describe the electro-optical challenges in realizing a bioinspired polarization imager, and in particular, we provide a detailed description of a recent low-power complementary metal-oxide-semiconductor (CMOS) polarization imager. Second, we focus on signal processing algorithms tailored for this new class of bioinspired polarization imaging sensors, such as calibration and interpolation. Third, the emergence of these sensors has enabled rapid progress in characterizing polarization signals and environmental parameters in nature, as well as several biomedical areas, such as label-free optical neural recording, dynamic tissue strength analysis, and early diagnosis of flat cancerous lesions in a murine colorectal tumor model. We highlight results obtained from these three areas and discuss future applications for these sensors.

Incidence of and Risk Factors for Reoperation and Revision Following Total Elbow Arthroplasty with an Anatomic Convertible Prosthesis.

BACKGROUND: Total elbow arthroplasty (TEA) remains a valuable tool for treating inflammatory, degenerative, and traumatic elbow conditions. This study aimed to understand the incidence of and risk factors for reoperation following TEA at a high-volume center utilizing an implant with a convertible linkage and the potential for anatomic lateral column reconstruction. METHODS: All patients undergoing primary TEA with the Latitude prosthesis (Stryker) from July 2001 to May 2020 were identified. Patient characteristics, the surgical indication, and implant characteristics were obtained. Additionally, the indications and timing were identified for reoperations. Postoperative radiographs were analyzed to assess cement quality, implant position, lateral column reconstruction, and distal humeral bone loss. RESULTS: Two hundred and nineteen TEAs were performed in 206 patients; 162 (74.0%) were in female patients, the mean patient age was 61 years (range, 23 to 95 years), and the mean follow-up was 11.8 years (range, 2 to 21 years). The most common indication for surgery was sequelae of trauma (36%). Ninety elbows (41.1%) required 200 reoperations at a mean of 19.6 months. Forty TEAs (18.3%) required revision of nonmodular implants, with 14 (6.4%) undergoing definitive explantation. The 5 and 10-year survivorship was 86.1% and 79.7%, respectively. The most common of the reasons for revision was aseptic loosening (53.8%), and the most common cause for non-revision reoperation was infection (23%). Younger age and greater follow-up duration were associated with greater revision and reoperation risks. Aseptic ulnar loosening was associated with a short ulnar stem length and component linkage (30% of short linked ulnar stems loosened; p < 0.001). Aseptic humeral loosening was associated with less-than-adequate cement-mantle quality (p = 0.04). CONCLUSIONS: Extended follow-up of the Latitude prosthesis at a high-volume center demonstrates that TEA continues to be hampered by a high reoperation rate, primarily due to infection and aseptic loosening. Technical factors such as good cement-mantle quality, longer stem length, and unlinked implants may play a role in preventing aseptic loosening. Further work is required to optimize long-term outcomes following TEA through improved understanding of appropriate surgical indications, techniques, and implant utilization. LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Supination Adduction Vertical Medial Malleolar Fracture Fixation with Buttress Plating vs a Novel Screw-Only Construct: A Cadaveric Biomechanical Study.

BACKGROUND: Supination adduction ankle fractures are unique among rotational ankle fractures as plate constructs are more commonly used than independent screws for medial malleolar fixation. The purpose of this study was to compare fracture displacement between plate fixation to a novel screw-only construct using a cadaveric biomechanical early-weightbearing model for the treatment of vertical medial malleolus fractures. METHODS: Six nonosteoporotic fresh-frozen cadaver shanks and feet in matched pairs underwent a vertical osteotomy of the medial malleolus to simulate the supination adduction type injury. Osteoporosis was measured using DEXA scans. One specimen from each pair was fixed with a one-third tubular buttress plate and the other with screw-only fixation. The specimens were then axially loaded for 100 000 cycles to simulate protected weightbearing, and subsequently loaded to failure in supination. Stiffness, fracture displacement, and load to failure were recorded. Statistical significance was set at P <.05. RESULTS: There were no measurable differences in displacement between the 2 constructs during axial cyclic loading after 100 000 cycles (plate, 0.74 ± 0.09 mm; screws, 0.79 ± 0.18 mm; P = .225). During supination and axial load to failure, the plate outperformed the screw construct. For load to failure (2 mm displacement) at the fracture site, the plate group failed at 716 ± 240 N, whereas the screw group failed at 567 ± 237 N (P = .015). During load to catastrophic failure, the plate group outperformed the screw group (plate, 6011 ± 1646 N; screws, 4578 ± 1837 N; P = .002). CONCLUSION: For vertical medial malleolar fractures, the screw-only construct demonstrated no statistical difference when compared to buttress plating for cyclical axial loading, simulating early weightbearing in a boot. However, buttress plating is 21% to 24% stronger than the screw-only fixation construct in overall strength and prevention of catastrophic failure when loading in a supinated position. CLINICAL RELEVANCE: The screw-only construct is biomechanically similar to a buttress plate when simulating early protected weightbearing. This suggests that early weightbearing as tolerated in a controlled ankle motion boot beginning 2 weeks postoperatively is mechanically safe for this fracture pattern and does not result in unacceptable amounts of fracture displacement. This construct may be useful as a less invasive treatment modality for the treatment of vertical medial malleolus fractures in select patients.

The Effect of Hospital and Surgeon Volumes on Complication Rates After Fixation of Peritrochanteric Hip Fractures.

OBJECTIVE: This study evaluates the relationship between hospital and surgeon volumes of peritrochanteric hip fracture fixation and complication rates. METHODS: Adults (60 years of age or older) who underwent surgical fixation for closed peritrochanteric fractures from 2009 to 2015 were identified using International Classification of Diseases 9 and 10 Clinical Modification and Procedural codes in the New York Statewide Planning and Research Cooperative System database. Readmission, reoperations, in-hospital mortality, and other adverse events were compared across surgeon and facility volumes. Statistical significance was set at P < 0.05. RESULTS: A total of 29,656 patients were included in the study. Low-volume (LV) facilities had higher rates of readmission [hazard ratio (HR) 1.07, 95% confidence interval (CI), 1.05-1.17], pneumonia (HR 1.36, 95% CI, 1.22-1.51), wound complications (HR 1.24, 95% CI, 1.03-1.49), and mortality (HR 1.15, 95% CI, 1.04-1.27) but lower rates of acute renal failure (HR 0.90, 95% CI, 0.83-0.98), deep vein thrombosis (HR 0.66, 95% CI, 0.55-0.78), and acute respiratory failure (HR 0.77, 95% CI, 0.62-0.95) than high-volume (HV) facilities. Patients treated by LV surgeons had lower rates of readmission (HR 0.92, 95% CI, 0.87-0.97) and deep vein thrombosis (HR 0.78, 95% CI, 0.66-0.94) but higher rates of acute renal failure (HR 1.13, 95% CI, 1.04-1.22) than those treated by HV surgeons. CONCLUSIONS: There are increased rates of mortality, readmission, and certain complications when peritrochanteric femur fractures are surgically managed at LV hospitals compared with those managed at HV hospitals. Thus, the benefit of a high-volume surgical facility is apparent in mortality and readmissions but not all complications. There was no significant decrease in complications if fixation was performed by HV surgeons relative to LV surgeons. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Rates of and Risk Factors for Trigger Finger after Open Carpal Tunnel Release.

Background We have anecdotally noticed a higher rate of trigger fingers (TFs) developing in patients who have undergone carpal tunnel release (CTR). Questions/Objective Is the rate of TFs after CTR greater compared to the nonoperative hand? Is the thumb more commonly involved postoperatively compared with spontaneous TFs? Do particular associated comorbidities increase this risk? Patients and Methods We queried our institutional database for patients who had undergone open CTR during a 2-year period and recorded the development of an ipsilateral TF after a CTR or a contralateral TF in the nonoperative hand. Patient demographics, comorbidities, concurrent initial procedures, time to diagnosis, and finger involvement were recorded. Results A total of 435 patients underwent 556 CTRs during this period. Furthermore, 46 ipsilateral TFs developed in 38 of 556 cases (6.83%) at an average of 228.1 ± 195.7 days after surgery. The thumb was most commonly involved (37.0%) followed by the ring finger (28.3%). The incidence rate of TF in the nonoperative hand during this period was 2.7%, with the ring finger and middle finger most commonly involved (33.3 and 28.6%, respectively). Only history of prior TF in either hand was found to be a significantly associated on Chi-square analysis and multivariable regression ( p < 0.001). Conclusion In patients with carpal tunnel syndrome, ipsilateral TFs occurred after 6.83% of CTRs, compared with a rate of 2.7% in the nonoperative hand, making it an important possible outcome to discuss with patients. The thumb was more commonly involved in triggering in the surgical hand compared with the nonoperative hand. Patients with a history of prior TFs in either hand were more likely to develop an ipsilateral TF after CTR. Level of Evidence This is a Level III, retrospective study.

Critical Under-Reporting of Hernia Mesh Properties and Development of a Novel Package Label.

BACKGROUND: With an array of hernia meshes with varying properties, intraoperative decision making for the optimal mesh is critical. Although meshes are subjected to regulatory review through the Food and Drug Administration, it is unknown whether mesh properties are visually accessible. To facilitate greater knowledge for the surgeon on mesh choice, we aimed to comprehensively analyze hernia mesh packaging and regulations. STUDY DESIGN: Labeling guidelines and 510(k) requirements across Food and Drug Administration-regulated products were analyzed and compared with mesh packaging. Packages and Instructions for Use were analyzed for commonly available hernia meshes. Literature review was conducted to understand recommended guidelines for mesh products. A novel hernia mesh packaging label was designed to rectify under-reporting. RESULTS: We found that food labels undergo critical scrutiny and detailed specifications, yet medical devices are not subjected to similar guidelines. The highest reported property on packages was the presence of a barrier (80%), and the lowest reported property was barrier composition (33%). For Instructions for Use, the lowest reported properties were mechanics (31%) and thickness (11%), both of which were not reported on packaging. Descriptive terms for pore size and mechanics were reported inconsistently. To overcome this under-reporting of properties, we propose a novel packaging label with properties chosen from regulatory guidelines, packaging analysis, and literature review. CONCLUSIONS: Although standardized terminology has been proposed in literature, property knowledge has not adequately permeated surgery, industry, or regulatory guidelines. There is extreme under-reporting and lack of consistency of clinically important mesh properties. Standardized packaging labels will provide accessibility of these properties and aim to bring standardized terminology into practice. With an increase in access to important properties, this can facilitate intraoperative decision making on a case-by-case basis.

Opioid Medication Use in the Surgical Patient: An Assessment of Prescribing Patterns and Use.

BACKGROUND: With the epidemic of prescription opioid abuse in the US, rates of opioid-related unintentional deaths have risen dramatically. However, few data exist comparing postoperative opioid prescriptions with patient use. We sought to better elucidate this relationship in surgical patients. STUDY DESIGN: A prospective cohort study was conducted of narcotic-naïve patients undergoing open and laparoscopic abdominal procedures on a minimally invasive surgery service. During the first 14 post-discharge days and at their first postoperative clinic visit, patients recorded pain scores and number of opioid pills taken. Clinical data were extracted from the medical record. Descriptive statistics were used in data analysis. RESULTS: From 2014 through 2017, one hundred and seventy-six patients completed postoperative pain surveys. Mean age was 60.4 ± 14.9 years and sex was distributed equally. Most patients (69.9%) underwent laparoscopic procedures. Hydrocodone-acetaminophen was the most commonly prescribed postoperative pain medication (118 patients [67.0%]), followed by oxycodone-acetaminophen (26 patients [14.8%]). Patients were prescribed a median of 150 morphine milligram equivalents (MME) (interquartile range [IQR] 150 to 225 MME), equivalent to twenty 5-mg oral oxycodone pills (IQR 20 to 30 pills). However, by their first postoperative visit, they had only taken a median 30 MME (IQR 10 to 90 MME), or 4 pills (IQR 1.3 to 12 pills). Eight (4.5%) patients received a refill or an additional prescription for pain medications. At the first postoperative visit, 76.7% of respondents were satisfied or very satisfied with their overall postoperative pain management. CONCLUSIONS: Postoperative patients might consume less than half of the opioid pills they are prescribed. More research is needed to standardize opioid prescriptions for postoperative pain management while reducing opioid diversion.

Real-time high-resolution measurement of collagen alignment in dynamically loaded soft tissue.

A technique for creating maps of the direction and strength of fiber alignment in collagenous soft tissues is presented. The method uses a division of focal plane polarimeter to measure circularly polarized light transmitted through the tissue. The architecture of the sensor allows measurement of the retardance and fiber alignment at the full frame rate of the sensor without any moving optics. The technique compares favorably to the standard method of using a rotating polarizer. How the new technique enables real-time capture of the full angular spread of fiber alignment and retardance under various cyclic loading conditions is illustrated.