Acellular Human Dermal Allograft Tuberoplasty Improved the Biomechanics in Mid-Range and Higher Abduction Angles in a Cadaveric Model of Massive Irreparable Rotator Cuff Tears.

Purpose: To evaluate the biomechanical effects of acellular human dermal allograft tuberoplasty (AHDAT) in a cadaveric model of an irreparable supraspinatus + anterior one-half infraspinatus (stage III) rotator cuff tear. Methods: Eight cadaveric shoulders were tested at 20°, 40°, and 60° of glenohumeral abduction (AB) and 0°, 30°, 60°, and 90° of external rotation (ER). Superior humeral translation, acromiohumeral distance, and subacromial contact were quantified for 4 conditions: (1) intact, (2) stage III tear (entire supraspinatus and anterior one-half infraspinatus), (3) single-layer AHDAT, and (4) double-layer AHDAT. Results: Stage III tear significantly increased superior translation at 20° and 40° AB and all ER angles and at 60° AB/60° ER (P ≤ .045 vs intact). Compared to the stage III tear, the single-layer AHDAT significantly decreased superior translation at 60° AB/60° ER (P = .003), whereas the double-layer AHDAT significantly decreased superior translation at 40° and 60° AB at all ER angles except 60° AB/0° ER (P ≤ .028). The stage III tear significantly decreased acromiohumeral distance at 20° AB (P ≤ .003); both grafts increased acromiohumeral distance to intact levels (P ≥ .055 vs intact). Stage III tear increased subacromial contact pressure at 20° and 40° AB/0° and 30° ER and at 60° AB/30° and 60° ER (P ≤ .034). Both AHDAT groups decreased contact pressure at 40° AB/30° and 60° ER back to intact, whereas the double-layer AHDAT also decreased contact pressure at 20° AB/0° and 60° ER and 60° AB/30° ER (P ≥ .051 vs intact). Conclusions: Both single- and double-layer grafts for AHDAT improved superior translation, subacromial contact characteristics, and acromiohumeral distance after a stage III rotator cuff tear, with varying effectiveness due to the position-dependent nature of greater tuberosity to acromial contact with abduction. Clinical Relevance: The best treatment for massive or irreparable rotator cuff tears is a matter of concern. The results of this study will help determine whether an acellular human dermal allograft tuberoplasty is a potential treatment option worthy of further investigation.

Younger age at initiation of subcutaneous treprostinil is associated with better response in pediatric Group 1 pulmonary arterial hypertension.

Children with severe Group 1 pulmonary arterial hypertension (PAH) have an unpredictable response to subcutaneous treprostinil (TRE) therapy, which may be influenced by age, disease severity, or other unknown variables at time of initiation. In this retrospective single-center cohort study, we hypothesized that younger age at TRE initiation, early hemodynamic response (a decrease in pulmonary vascular resistance by ≥30% at follow-up catheterization), and less severe baseline hemodynamics (Rp:Rs < 1.1) would each be associated with better clinical outcomes. In 40 pediatric patients with Group I PAH aged 17 days-18 years treated with subcutaneous TRE, younger age (cut-off of 6-years of age, AUC 0.824) at TRE initiation was associated with superior 5-year freedom from adverse events (94% vs. 39%, p = 0.002), better WHO functional class (I or II: 88% vs. 39% p = 0.003), and better echocardiographic indices of right ventricular function at most recent follow-up. Neither early hemodynamic response nor less severe baseline hemodynamics were associated with better outcomes. Patients who did not have a significant early hemodynamic response to TRE by first follow-up catheterization were unlikely to show subsequent improvement in PVRi (1/8, 13%). These findings may help clinicians counsel families and guide clinical decision making regarding the timing of advanced therapies.

Biomechanical comparison of open Bankart repair vs. conjoint tendon transfer in a 10% anterior glenoid bone loss shoulder instability model.

BACKGROUND: The treatment of shoulder instability in patients with subcritical glenoid bone loss poses a difficult problem for surgeons as new evidence supports a higher failure rate when a standard arthroscopic Bankart repair is used. The purpose of this study was to compare a conjoint tendon transfer (soft-tissue Bristow) to an open Bankart repair in a cadaveric instability model of 10% glenoid bone loss. METHODS: Eight cadaveric shoulders were tested using a custom testing system that allows for a 6-degree-of-freedom positioning of the glenohumeral joint. The rotator cuff muscles were loaded to simulate physiologic muscle conditions. Four conditions were tested: (1) intact, (2) Bankart lesion with 10% bone loss, (3) conjoint tendon transfer, and (4) open Bankart repair. Range of motion, glenohumeral kinematics, and anterior-inferior translation at 60° of external rotation with 20 N, 30 N, and 40 N were measured in the scapular and coronal planes. Glenohumeral joint translational stiffness was calculated as the linear fit of the translational force-displacement curve. Force to anterior-inferior dislocation was also measured in the coronal plane. Repeated measures analysis of variance with a Bonferroni correction was used for statistical analysis. RESULTS: A Bankart lesion with 10% bone loss increased the range of motion in both the scapular (P = .001) and coronal planes (P = .001). The conjoint tendon transfer had a minimal effect on the range of motion (vs. intact P = .019, .002), but the Bankart repair decreased the range of motion to intact (P = .9, .4). There was a significant decrease in glenohumeral joint translational stiffness for the Bankart lesion compared with intact in the coronal plane (P = .021). The conjoint tendon transfer significantly increased stiffness in the scapular plane (P = .034), and the Bankart repair increased stiffness in the coronal plane (P = .037) compared with the Bankart lesion. The conjoint tendon transfer shifted the humeral head posteriorly at 60° and 90° of external rotation in the scapular plane. The Bankart repair shifted the head posteriorly in maximum external rotation in the coronal plane. There was no significant difference in force to dislocation between the Bankart repair (75.8 ± 6.6 N) and the conjoint tendon transfer (66.5 ± 4.4 N) (P = .151). CONCLUSION: In the setting of subcritical bone loss, both the open Bankart repair and conjoint tendon transfer are biomechanically viable options for the treatment of anterior shoulder instability; further studies are needed to extrapolate these data to the clinical setting.

Current practices for refractory chylothorax following congenital heart surgery.

INTRODUCTION: Chylothorax following paediatric cardiac surgery is associated with significant morbidity, particularly those that are refractory to conservative therapy. It is our impression that there is important variability in the medical, surgical, and interventional therapies used to manage refractory chylothorax between congenital heart programmes. We therefore conducted a survey study of current practices for managing refractory chylothorax. METHODS: The Chylothorax Work Group, formed with the support of the Pediatric Cardiac Critical Care Consortium, designed this multi-centre survey study with a focus on the timing and indication for utilising known therapies for refractory chylothorax. The survey was sent to one chylothorax expert from each Work Group centre, and results were summarised and reported as the frequency of given responses. RESULTS: Of the 20 centres invited to participate, 17 (85%) submitted complete responses. Octreotide (13/17, 76%) and sildenafil (8/17, 47%) were the most utilised medications. Presently, 9 (53%) centres perform pleurodesis, 15 (88%) perform surgical thoracic duct ligation, 8 (47%) perform percutaneous lymphatic interventions, 6 (35%) utilise thoracic duct decompression procedures, and 3 (18%) perform pleuroperitoneal shunts. Diagnostic lymphatic imaging is performed prior to surgical thoracic duct ligation in only 7 of the 15 (47%) centres that perform the procedure. Respondents identified barriers to referring and transporting patients to centres with expertise in lymphatic interventions. CONCLUSIONS: There is variability in the treatment of refractory post-operative chylothorax across a large group of academic heart centres. Few surveyed heart centres have replaced surgical thoracic duct ligation or pleurodesis with image-guided selective lymphatic interventions.

The Gluteus Medius Experiences Significant Excursion With Hip Flexion.

Purpose: To evaluate the effect of hip flexion and rotation on excursion of the gluteus medius (Gmed) and minimus (Gmin) myotendinous unit. Methods: Seven hips from 4 cadaveric specimens (males, 68.5 ± 18.3 years old) were dissected to isolate the Gmed posterior and lateral insertions and the Gmin proximal and distal insertions. Sutures were placed from tendon insertions through origins created in the iliac fossa to simulate the myotendinous unit. A load of 10N was applied. Myotendinous excursion was measured at 10° hip extension and 0°, 45°, and 90° of hip flexion in neutral rotation, and from maximum internal and external rotation in 90° flexion. The amount of abduction and rotation was also measured at each flexion position with 20N applied to each tendon. Repeated-measures analysis of variance with Tukey post hoc was used for statistics. Results: Gmed-lateral excursion ranged from 2.4 ± 0.4 mm in 10° of hip extension to 23.0 ± 1.5 mm in 90° of flexion (P < .001), and Gmed-posterior excursion ranged from 0.92 ± 0.5 mm in 10° of extension to 38.1 ± 1.1 mm in 90° of flexion (P < .001). Gmin excursion shortened with hip flexion from 4.2 ± 0.3 mm in 10° of extension to -0.2 ± 1.5 mm in 90° of flexion (Gmin-prox: P = .525, Gmin-distal: P < .001). At 90° flexion from maximum internal to maximum external rotation, Gmin-distal and proximal demonstrated a 92.6% and 51.3% increase in excursion, respectively (P < .001). Gmed-lateral and Gmed-posterior demonstrated 49.4% and 23.1% increase in excursion with external rotation, respectively (P < .001). Conclusions: The Gmed myotendinous unit undergoes significant excursion with hip flexion, whereas both Gmed and Gmin had significant excursion with femoral external rotation in 90° flexion. Clinical Relevance: It is important to understand whether active or passive hip flexion or rotation in the early postoperative period causes excessive strain to an abductor tendon repair. We found that consideration should be given to limit flexion after Gmed repair and external rotation after Gmed or Gmin repairs.

Biomechanical characteristics of a new looping stitch versus the classic Krackow stitch for distal biceps fixation.

Background: The purpose of this study was to quantify the biomechanical characteristics of a new looping stitch, developed with the concepts of a looping, locking stitch that decreases needle penetrations of the tendon, and compare it to a classic Krackow stitch for distal biceps suture-tendon fixation. Methods: The Krackow stitch with No. 2 braided suture and the looping stitch with a No. 2 braided suture loop attached to a 25-mm-length by 1.3-mm-width polyblend suture tape were compared. The Looping stitch was performed with single strand locking loops and wrapping suture around the tendon, resulting in half the needle penetrations through the graft compared to the Krackow stitch. Ten matched pairs of human distal biceps tendons were used. One side of each pair was randomly assigned to either the Krackow or the looping stitch, and the contralateral side was used for the other stitch. For biomechanical testing, each construct was preloaded to 5 N for 60 seconds, followed by cyclic loading to 20 N, 40 N, and 60 N for 10 cycles each, and then loaded to failure. The deformation of the suture-tendon construct, stiffness, yield load, and ultimate load were quantified. Comparisons between the Krackow and looping stitches were performed with a paired t-test using P < .05 as statistically significant. Results: The Krackow stitch and looping stitch had no significant difference in stiffness, peak deformation, or nonrecoverable deformation after 10 cycles of loading to 20 N, 40 N, and 60 N. There was no difference between the Krackow stitch and looping stitch in load applied to displacement of 1 mm, 2 mm, and 3 mm. The ultimate load showed that the looping stitch was significantly stronger compared to the Krackow stitch (Krackow stitch: 223.7 ± 50.3 N; looping stitch: 312.7 ± 53.8 N) (P = .002). The failure modes were either suture breakage or tendon cut through. For the Krakow stitch, there was 1 suture breakage and 9 tendons cut through. For the looping stitch, there were five suture breakages, and five tendons cut through. Conclusions: With fewer needle penetrations, incorporation of 100% of the tendon diameter, and a higher ultimate load to failure compared to the Krackow stitch, the Looping stitch may be a viable option to reduce deformation, failure, and cut-out of the suture-tendon construct.

Acute Hemodynamics in the Fontan Circulation: Open-Label Study of Vasopressin.

OBJECTIVE: To describe the acute hemodynamic effect of vasopressin on the Fontan circulation, including systemic and pulmonary pressures and resistances, left atrial pressure, and cardiac index. DESIGN: Prospective, open-label, nonrandomized study (NCT04463394). SETTING: Cardiac catheterization laboratory at Lucile Packard Children's Hospital, Stanford. PATIENTS: Patients 3-50 years old with a Fontan circulation who were referred to the cardiac catheterization laboratory for hemodynamic assessment and/or intervention. INTERVENTIONS: A 0.03 U/kg IV (maximum dose 1 unit) bolus of vasopressin was administered over 5 minutes, followed by a maintenance infusion of 0.3 mU/kg/min (maximum dose 0.03 U/min). MEASUREMENTS AND MAIN RESULTS: Comprehensive cardiac catheterization measurements before and after vasopressin administration. Measurements included pulmonary artery, atrial, and systemic arterial pressures, oxygen saturations, and systemic and pulmonary flows and resistances. There were 28 patients studied. Median age was 13.5 (9.1, 17) years, and 16 (57%) patients had a single or dominant right ventricle. Following vasopressin administration, systolic blood pressure and systemic vascular resistance (SVR) increased by 17.5 (13.0, 22.8) mm Hg ( Z value -4.6, p < 0.001) and 3.8 (1.8, 7.5) Wood Units ( Z value -4.6, p < 0.001), respectively. The pulmonary vascular resistance (PVR) decreased by 0.4 ± 0.4 WU ( t statistic 6.2, p < 0.001), and the left atrial pressure increased by 1.0 (0.0, 2.0) mm Hg ( Z value -3.5, p < 0.001). The PVR:SVR decreased by 0.04 ± 0.03 ( t statistic 8.1, p < 0.001). Neither the pulmonary artery pressure (median difference 0.0 [-1.0, 1.0], Z value -0.4, p = 0.69) nor cardiac index (0.1 ± 0.3, t statistic -1.4, p = 0.18) changed significantly. There were no adverse events. CONCLUSIONS: In Fontan patients undergoing cardiac catheterization, vasopressin administration resulted in a significant increase in systolic blood pressure, SVR, and left atrial pressure, decrease in PVR, and no change in cardiac index or pulmonary artery pressure. These findings suggest that in Fontan patients vasopressin may be an option for treating systemic hypotension during sedation or general anesthesia.

Biomechanical Evaluation of TensionLoc Versus the Double Spike Plate for ACL Graft Tibial Fixation.

Background: The optimal tibial fixation of anterior cruciate ligament (ACL) reconstruction (ACLR) grafts remains controversial. Purpose/Hypothesis: The purpose of this study was to compare the biomechanical characteristics of the TensionLoc (TL) cortical fixation device with the Double Spike Plate (DSP) fixation device for ACL tibial fixation using both bone-patellar tendon-bone (BTB) and quadriceps grafts. It was hypothesized that there would be no differences in biomechanical characteristics between the fixation devices regardless of graft type. Study Design: Controlled laboratory study. Methods: ACLR was performed on 14 matched-pair cadaveric knee specimens-7 pairs using quadriceps grafts (n = 3 male cadaveric knee specimens; n = 4 female cadaveric knee specimens; age, 51 ± 8 years) and 7 pairs using BTB grafts (n = 3 male cadaveric knee specimens; n = 4 female cadaveric knee specimens; age, 50 ± 7 years). One side of each pair was randomized to receive DSP fixation, and the contralateral side received TL fixation. Specimens underwent cyclic ramp loading (10 cycles each at 50-100 N, 50-250 N, and 50-400 N), followed by load-to-failure testing, with the tensile force in line with the tibial tunnel. Results between the 2 fixation types were compared with a paired t test. Results: For the quadriceps graft, there were no significant differences in cyclic loading or load-to-failure characteristics between fixation types (P≥ .092 for all parameters). For the BTB graft, TL fixation resulted in higher stiffness than DSP at all cyclic testing cycles except for cycle 1 during 100-N loading and had lower displacement at 250-N loading (3.4 ± 0.1 vs 5.4 ± 0.3 mm; P = .045). For load to failure, TL fixation resulted in higher stiffness than DSP fixation (232 ± 3.1 vs 188.4 ± 6.4 N/mm; P = .046); however, all other load-to-failure parameters were not statistically different (P≥ .135 for all parameters). Conclusion: With the quadriceps tendon graft, there were no significant differences in biomechanical characteristics between TL and DSP ACL tibial fixations; however, with BTB grafts, the TL tibial fixation demonstrated greater biomechanical integrity than the DSP tibial fixation. Clinical Relevance: The TL fixation device may provide an alternative ACL tibial fixation option for BTB and soft tissue grafts.

Prediction Model with External Validation for Early Detection of Postoperative Pediatric Chylothorax.

Earlier diagnosis of chylothorax following pediatric cardiac surgery is associated with decreased duration of chylothorax. Pleural fluid testing is used to diagnosis chylothorax which may delay detection in patients who are not enterally fed at time of chylothorax onset. Our aim was to develop and externally validate a prediction model to detect chylothorax earlier than pleural fluid testing in pediatric patients following cardiac surgery. A multivariable logistic regression model was developed to detect chylothorax using a stepwise approach. The model was developed using data from patients < 18 years following cardiac surgery from Primary Children's Hospital, a tertiary-care academic center, between 2017 and 2020. External validation used a contemporary cohort (n = 171) from Lucille Packard Children's Hospital. A total of 763 encounters (735 patients) were analyzed, of which 72 had chylothorax. The final variables selected were chest tube output (CTO) the day after sternal closure (dichotomized at 15.6 mL/kg/day, and as a continuous variable) and delayed sternal closure. The highest odds of chylothorax were associated with CTO on post-sternal closure day 1 > 15.6 mL/kg/day (odds ratio 11.3, 95% CI 6,3, 21.3). The c-statistic for the internal and external validation datasets using the dichotomized CTO variable were 0.78 (95% CI 0.73, 0.82) and 0.84 (95% CI, 0.78, 0.9) and performance improved when using CTO as a continuous variable (OR 0.84, CI: 95% CI 0.80, 0.87). Using the models described, chylothorax after pediatric cardiac surgery may be detected earlier and without reliance on enteral feeds.

2022 Bernard Morrey Award: the elbow ulnar collateral ligament complex demonstrates region specific stretching and recovery characteristics with valgus loading.

BACKGROUND: The objective of this study was to quantify the valgus laxity and strain of the elbow ulnar collateral ligament (UCL) complex after repeated valgus stretching and subsequent recovery. Understanding these changes may have important implications in improving strategies for injury prevention and treatment. The hypothesis was that the UCL complex will demonstrate a permanent increase in valgus laxity and region-specific increase in strain as well as region-specific recovery characteristics. METHODS: Ten cadaveric elbows (7M, 3F, 61.7 ± 2.7 years) were used. Valgus angle and strain of the anterior and posterior bands of the anterior bundle and the posterior bundle were measured at 1 Nm, 2.5 Nm, 5 Nm, 7.5 Nm, and 10 Nm of valgus torque at 70° of flexion for: (1) intact UCL, (2) stretched UCL, and (3) rested UCL. To stretch the UCL, elbows were cycled with increasing valgus torque at 70° of flexion (10 Nm-20 Nm in 1 Nm increments) until the valgus angle increased 8° from the intact valgus angle measured at 1Nm. This position was held for 30 minutes. Specimens were then unloaded and rested for 2 hours. Linear mixed effects model with Tukey's post hoc test was used for statistical analysis. RESULTS: Stretching significantly increased valgus angle compared to the intact condition 3.2° ± 0.2° (P < .001). Strains of both the anterior and posterior bands of the anterior bundle were significantly increased from intact by 2.8% ± 0.9% (P = .015) and 3.1% ± 0.9% (P = .018), respectively at 10 Nm. Strain in the distal segment of the anterior band was significantly higher than the proximal segment with loads of 5 Nm and higher (P < .030). After resting, the valgus angle significantly decreased from the stretched condition by 1.0° ± 0.1° (P < .001) but failed to recover to intact levels (P < .004). After resting, the posterior band had a significantly increased strain compared to the intact state of 2.6% ± 1.4% (P = .049) while the anterior band was not significantly different from intact. CONCLUSION: After repeated valgus loading and subsequent resting, the UCL complex demonstrated permanent stretching with some recovery but not to intact levels. The anterior band demonstrated increased strain in the distal segment compared to the proximal segment with valgus loading. The anterior band was able to recover to strain levels similar to intact after resting, while the posterior band did not.

Latissimus dorsi and teres major tendon transfer for irreparable anterosuperior rotator cuff tear improves kinematics and internal rotation compared to latissimus dorsi tendon transfer.

INTRODUCTION: Latissimus dorsi and teres major (LDTM) tendon transfer has demonstrated better clinical outcomes compared to Latissimus dorsi (LD) transfer for irreparable anterosuperior cuff (subscapularis/supraspinatus) tears; however, the biomechanical effects of these procedures are unknown. Therefore, the objective of this study was to compare kinematics and internal rotation of LDTM transfer to LD transfer for anterosuperior cuff tear. METHODS: Eight cadaveric shoulders were tested in four conditions; (1) intact, (2) anterosuperior rotator cuff tear, (3) LDTM transfer, and (4) LD transfer. Glenohumeral kinematics and internal rotation at 0°, 30°, and 60° of glenohumeral abduction in the scapular plane were measured. Muscle loading was applied based on physiological cross-sectional area ratios with three muscle loading conditions to simulate potentially increased tension due to the advanced insertion site of the transferred tendons. RESULTS: The anterosuperior rotator cuff tear leads to a significant superior shift of the humeral head compared to intact at 0° and 30° abduction (p < 0.039). Both the LDTM (p < 0.047) and LD transfers (p < 0.032) significantly shifted the humeral head inferiorly compared to the tear condition.; however, the LDTM transfer shifted the head in the anteroinferior direction compared to the LD transfer at 60° abduction and 30° ER (p < 0.045). Both LDTM and LD transfer significantly increased internal resting rotation (p < 0.008) and maximum internal rotation (p < 0.008) compared to anterosuperior rotator cuff tear and intact at 30° and 60° abduction. LDTM transfer resulted in a significant internal resting rotation compared with the LD transfer at 30° abduction with double muscle loading (p = 0.02). At 0° abduction, the LDTM transfer (p < 0.027) significantly increased maximum internal rotation compared to anterosuperior rotator cuff tear and intact. CONCLUSION: Although both LDTM and LD tendon transfer improved the abnormal humeral head apex position and internal rotation compared with the tear condition, the LDTM transfer was biomechanically superior to the LD transfer in a cadaveric model.

Superior Capsule Reconstruction With Fascia Lata Allograft Has Initial Stiffness and Ultimate Load Comparable to the Native Shoulder Superior Capsule: A Cadaveric Biomechanical Study.

PURPOSE: The purpose of this study was to compare the biomechanical characteristics of a fascia lata superior capsule reconstruction (FL-SCR) to the native superior capsule. METHODS: The native superior capsule of 8 cadaveric shoulders was tested with cyclic loading from 10 to 50 N for 30 cycles in 20° of glenohumeral abduction followed by load to failure at 60 mm/min. Following native superior capsule testing, FL-SCR was performed, which was tested as described for the native capsule. Paired t test was used for statistical analyses with P < .05 for significance. RESULTS: The stiffness for cycle 1 to 50 N was significantly higher for the native superior capsule compared to the FL-SCR (P = .001). By cycle 30, the stiffness between the two was not statistically different (P = .734). During load to failure, the initial stiffness to 2 mm for the FL-SCR and the native superior capsule was not statistically different (P = .262). The linear stiffness and yield load of the native superior capsule were significantly greater than that of the FL-SCR (94.5 vs 28.0 N/mm, P = .013; 386.9 vs 123.8 N, P = .029). There was no significant difference in ultimate load between the native superior capsule and the FL-SCR (444.9 vs 369.0 N, P = .413). CONCLUSIONS: FL-SCR has initial stiffness and ultimate load similar to the native superior capsule. CLINICAL RELEVANCE: The biomechanical properties of FL allograft make it an appealing option as a graft choice for superior capsule reconstruction.

Role of left atrial hypertension in pulmonary hypertension associated with bronchopulmonary dysplasia.

Left atrial hypertension (LAH) may contribute to pulmonary hypertension (PH) in premature infants with bronchopulmonary dysplasia (BPD). Primary causes of LAH in infants with BPD include left ventricular diastolic dysfunction or hemodynamically significant left to right shunt. The incidence of LAH, which is definitively diagnosed by cardiac catheterization, and its contribution to PH is unknown in patients with BPD-PH. We report the prevalence of LAH in an institutional cohort with BPD-PH with careful examination of hemodynamic contributors and impact on patient outcomes. This single-center, retrospective cohort study examined children <2 years of age with BPD-PH who underwent cardiac catheterization at Lucile Packard Children's Hospital Stanford. Patients with unrepaired simple shunt congenital heart disease (CHD) and pulmonary vein stenosis (only 1 or 2 vessel disease) were included. Patients with complex CHD were excluded. From April 2010 to December 2021, 34 patients with BPD-PH underwent cardiac catheterization. We define LAH as pulmonary capillary wedge pressure (PCWP) or left atrial pressure (LAP) of at least 10 mmHg. In this cohort, median PCWP was 8 mmHg, with LAH present in 32% (n = 11) of the total cohort. A majority (88%, n = 30) of the cohort had severe BPD. Most patients had some form of underlying CHD and/or pulmonary vein stenosis: 62% (n = 21) with an atrial septal defect or patent foramen ovale, 62% (n = 21) with patent ductus arteriosus, 12% (n = 4) with ventricular septal defect, and 12% (n = 4) with pulmonary vein stenosis. Using an unadjusted logistic regression model, baseline requirement for positive pressure ventilation at time of cardiac catheterization was associated with increased risk for LAH (odds ratio 8.44, 95% CI 1.46-48.85, p = 0.02). Small for gestational age birthweight, sildenafil use, and CHD were not associated with increased risk for LAH. LAH was associated with increased risk for the composite outcome of tracheostomy and/or death, with a hazard ratio of 6.32 (95% CI 1.72, 22.96; p = 0.005). While the etiology of BPD-PH is multifactorial, LAH is associated with PH in some cases and may play a role in clinical management and patient outcomes.

Virtual Transcatheter Interventions for Peripheral Pulmonary Artery Stenosis in Williams and Alagille Syndromes.

Background Despite favorable outcomes of surgical pulmonary artery (PA) reconstruction, isolated proximal stenting of the central PAs is common clinical practice for patients with peripheral PA stenosis in association with Williams and Alagille syndromes. Given the technical challenges of PA reconstruction and the morbidities associated with transcatheter interventions, the hemodynamic consequences of all treatment strategies must be rigorously assessed. Our study aims to model, assess, and predict hemodynamic outcomes of transcatheter interventions in these patients. Methods and Results Isolated proximal and "extensive" interventions (stenting and/or balloon angioplasty of proximal and lobar vessels) were performed in silico on 6 patient-specific PA models. Autoregulatory adaptation of the cardiac output and downstream arterial resistance was modeled in response to intervention-induced hemodynamic perturbations. Postintervention computational fluid dynamics predictions were validated in 2 stented patients and quantitatively assessed in 4 surgical patients. Our computational methods accurately predicted postinterventional PA pressures, the primary indicators of success for treatment of peripheral PA stenosis. Proximal and extensive treatment achieved median reductions of 14% and 40% in main PA systolic pressure, 27% and 56% in pulmonary vascular resistance, and 10% and 45% in right ventricular stroke work, respectively. Conclusions In patients with Williams and Alagille syndromes, extensive transcatheter intervention is required to sufficiently reduce PA pressures and right ventricular stroke work. Transcatheter therapy was shown to be ineffective for long-segment stenosis and pales hemodynamically in comparison with published outcomes of surgical reconstruction. Regardless of the chosen strategy, a virtual treatment planning platform could identify lesions most critical for optimizing right ventricular afterload.

Biomechanical Assessment of a V-Shaped Semitendinosus Allograft Anterior Cable Reconstruction for Irreparable Rotator Cuff Tears.

PURPOSE: The purpose of this study was to biomechanically assess superior stability, subacromial contact pressures, and glenohumeral kinematics of a V-shaped anterior cable reconstruction with semitendinosus allograft (VST) in a massive rotator cuff tear (MCT) model. METHODS: Eight cadaveric shoulders (mean age, 66 years; range, 48 to 72 years) were tested with a custom testing system used to evaluate superior translation, subacromial contact pressure, and glenohumeral kinematics at 0°, 20°, and 40° glenohumeral abduction and 0°, 30°, 60°, and 90° of external rotation (ER). Conditions tested included (1) native state, (2) MCT (complete supraspinatus and ½ infraspinatus), a (3) VST. The VST was secured medially on the glenoid with 1 anchor and on the greater tuberosity with a double-row configuration using 4 anchors. RESULTS: The VST significantly decreased superior translation compared to the MCT at 0° and 20° glenohumeral abduction for 0°, 30°, and 60° humeral rotation and at 40° abduction and 0° degrees humeral rotation (P < .05). Superior translation following the VST remained significantly greater than the intact state at 0° abduction and 60° and 90° ER (P = .039 and 0.007, respectively) and 20° abduction and 30°, 60°, and 90° ER (P = .048, .003, and .004, respectively). The VST restored peak subacromial contact pressure to intact levels for all positions except 40° abduction and 60° ER. The VST did not statistically affect humeral head kinematics compared to the intact condition. CONCLUSIONS: In a biomechanical model, a VST anterior cable reconstruction partially restores superior stability and reduces peak subacromial contact pressure associated with an MCT, without affecting glenohumeral kinematics. The technique may be a consideration in the treatment of an irreparable MCT with isolated anterior cable disruption. CLINICAL RELEVANCE: The VST may provide an option for treatment of irreparable MCTs with anterior rotator cable disruption.

Human Dermal Allograft Superior Capsule Reconstruction With Graft Length Determined at Glenohumeral Abduction Angles of 20° and 40° Decreases Joint Translation and Subacromial Pressure Without Compromising Range of Motion: A Cadaveric Biomechanical Study.

PURPOSE: To compare the biomechanical effects of superior capsule reconstruction (SCR) graft fixation length determined at 20° and 40° of glenohumeral (GH) abduction. METHODS: Humeral translation, rotational range of motion (ROM), and subacromial contact pressure were quantified at 0°, 30°, and 60° of GH abduction in the scapular plane in 6 cadaveric shoulders for the following states: intact, massive rotator cuff tear, SCR with dermal allograft fixed at 20° of GH abduction (SCR 20), and SCR with dermal allograft fixed at 40° of GH abduction (SCR 40). Statistical analysis was conducted using a repeated-measures analysis of variance and a paired t test (P < .05). RESULTS: A massive cuff tear significantly increased total ROM compared with the intact state at 0° and 60° of abduction. SCR 20 or SCR 40 did not affect ROM. Compared with the intact state, the massive cuff tear model significantly increased superior translation by an average of 4.6 ± 0.5 mm in 9 of 12 positions (P ≤ .002). Both SCR 20 and SCR 40 reduced superior translation compared with the massive cuff tear model (P < .05); however, SCR 40 significantly decreased superior translation compared with SCR 20 at 0° of abduction (P ≤ .046). Peak subacromial pressure for the massive cuff tear model increased by an average of 486.8 ± 233.9 kPa relative to the intact state in 5 of 12 positions (P ≤ .037). SCR 20 reduced peak subacromial pressure in 2 of 12 positions (P ≤ .012), whereas SCR 40 achieved this in 6 of 12 positions (P ≤ .024). CONCLUSIONS: SCR with dermal allograft fixed at 20° or 40° of GH abduction decreases GH translation and subacromial pressure without decreasing ROM. CLINICAL RELEVANCE: With an increasing abduction angle for graft fixation, the medial-to-lateral graft length is decreased and the graft tension is effectively increased. Surgeons may increase shoulder stability without restricting ROM by fixing the graft at higher abduction angles. However, surgeons should remain cognizant of potential graft failure due to increased tension.

Comprehensive diagnostic catheterization in children with major aortopulmonary collateral arteries: A review of catheterization technique and anatomic nomenclature.

Achieving an optimal surgical result in patients with major aortopulmonary collateral arteries (MAPCAs) requires a thorough preoperative evaluation of the anatomy and physiology of the pulmonary circulation. This review provides a detailed description of diagnostic catheterization in patients with MAPCAs, including a summary of catheterization techniques, an overview of commonly used terms, and a review of MAPCA and pulmonary artery angiographic anatomy.

Load-to-failure characteristics of patellar tendon allograft superior capsule reconstruction compared with the native superior capsule.

BACKGROUND: The potential use of a patellar tendon allograft for superior capsular reconstruction has been demonstrated biomechanically; however, there are concerns regarding compromised fixation strength owing to the longitudinal orientation of the fibers in the patellar tendon. Therefore, the purpose of this study was to compare the fixation strength of superior capsule reconstruction using a patellar tendon allograft to the intact superior capsule. METHODS: The structural properties of the intact native superior capsule (NSC) followed by superior capsular reconstruction using a patellar tendon allograft (PT-SCR) were tested in eight cadaveric specimens. The scapula and humerus were potted and mounted onto an Instron testing machine in 20 degrees of glenohumeral abduction. Humeral rotation was set to achieve uniform loading across the reconstruction. Specimens were preloaded to 10 N followed by cyclic loading from 10 N to 50 N for 30 cycles, then load to failure at a rate of 60 mm/min. Video digitizing software was used to quantify the regional deformation characteristics. RESULTS: During cyclic loading, there was no difference found in stiffness between PT-SCR and NSC (cycle 1 - PT-SCR: 12.9 ± 3.6 N/mm vs. NSC: 22.5 ± 1.6 N/mm; P = .055 and cycle 30 - PT-SCR: 27.3 ± 1.4 N/mm vs. NSC: 25.4 ± 1.7 N/mm; P = .510). Displacement at the yield load was not significantly different between the two groups (PT-SCR: 7.0 ± 1.0 mm vs. NSC: 6.5 ± 0.3 mm; P = .636); however, at the ultimate load, there was a difference in displacement (PT-SCR: 20.7 ± 1.1 mm vs. NSC: 8.1 ± 0.5 mm; P < .001). There was a significant difference at both the yield load (PT-SCR: 71.4 ± 2.2 N vs. NSC: 331.6 ± 56.6 N; P = .004) and the ultimate load (PT-SCR: 217.1 ± 26.9 N vs. NSC: 397.7 ± 62.4 N; P = .019). At the yield load, there was a difference found in the energy absorbed (PT-SCR: 84.4 ± 8.9 N-mm vs. NSC: 722.6 ± 156.8 N-mm; P = .005), but no difference in energy absorbed was found at the ultimate load. CONCLUSIONS: PT-SCR resulted in similar stiffness to NSC at lower loads, yield displacement, and energy absorbed to ultimate load. The ultimate load of the PT-SCR was approximately 54% of the NSC, which is comparable with the percent of the ultimate load in rotator cuff repair and the intact supraspinatus at time zero.

Biceps Box Configuration for Superior Capsule Reconstruction of the Glenohumeral Joint Decreases Superior Translation but Not to Native Levels in a Biomechanical Study.

PURPOSE: To quantitatively biomechanically assess superior stability, subacromial contact pressures, and glenohumeral kinematics of an in situ biceps tenodesis and a box-shaped long head of the biceps tendon (LHBT) superior capsule reconstruction (SCR) in a superior massive rotator cuff tear (MCT) model. METHODS: Eight cadaveric shoulders (mean age, 62 years; range, 46-70 years) were tested with a custom testing system used to evaluate range of motion, superior translation, and subacromial contact pressure at 0°, 20°, and 40° of abduction. Conditions tested included native state, MCT (complete supraspinatus and one-half of the infraspinatus), a box-shaped LHBT SCR, and an in situ biceps tenodesis. The box-shaped SCR was performed by maintaining the biceps origin, securing 2 corners to the greater tuberosity, and one corner to the posterior glenoid. The in situ tenodesis was performed anatomically at the top of the articular margin in the same shoulder after take-down of the box SCR. RESULTS: Range of motion was not impaired with either repair construct (P > .05). The box SCR decreased superior translation by approximately 2 mm compared with the MCT at 0°, but translation remained greater compared with the intact state in nearly every testing position. The in situ tenodesis had no effect on superior translation. Peak subacromial contact pressure was increased in the MCT at 0° and 20° abduction compared with the native state but not different between the native and box SCR at the same positions. CONCLUSIONS: A box-shaped SCR using the native biceps tendon partially restores increased superior translation and peak subacromial contact pressure due to MCT. The technique may have a role in augmentation of an irreparable MCT. CLINICAL RELEVANCE: The box-shaped LHBT SCR technique may have a role in augmentation of an irreparable MCT.