Intracapsular Pressure Research Articles

Double capsulorhexis technique for safe phacoemulsification in intumescent cataract

Intumescent white cataracts are a challenge for novice and experienced surgeons alike. Creating a continuous curvilinear capsulorhexis may pose a problem in these cataracts due to many factors like increased intra capsular pressure, absence of red reflex, poor visibility, fragile or calcified anterior capsule.[1] These cataracts tend to have a shallow anterior chamber and presence of fluid vacuoles or sectoral markings in subcapsular area which can be seen on slit lamp biomicroscopy.[2] Argentinian flag sign, which is a radial tear in anterior capsule, can occur while creating capsulorhexis, due to raised intracapsular pressure.[3] Radial tears extending to the equator, makes phacoemulsification unsafe, since it may lead to further complications such as extension of the tear to posterior capsule, nucleus drop in vitreous cavity and difficulty with IOL placement. This video demonstrates the steps of 2 staged capsulorhexis, to prevent radial extension while operating a type 1 (liquified cortex) intumescent cataract and type 2 (no liquified cortex, only tense fibres) intumescent cataract.[4]

Pathophysiological Link and Treatment Implication of Heart Failure and Preserved Ejection Fraction in Patients with Chronic Kidney Disease.

Heart failure with preserved ejection fraction (HFpEF) results from a complex interplay of age, genetic, cardiac remodeling, and concomitant comorbidities including hypertension, obesity, diabetes, and chronic kidney disease (CKD). Renal failure is an important comorbidity of HFpEF, as well as a major pathophysiological mechanism for those patients at risk of developing HFpEF. Heart failure (HF) and CKD are intertwined conditions sharing common disease pathways; the so-called "kidney tamponade", explained by an increase in intracapsular pressure caused by fluid retention, is only the latest model to explain renal injury in HF. Recognizing the different phenotypes of HFpEF remains a real challenge; the pathophysiological mechanisms of renal dysfunction may differ across the HF spectrum, as well as the prognostic role. A better understanding of the role of cardiorenal interactions in patients with HF in terms of symptom status, disease progression, and prognosis remains essential in HF management. Historically, patients with HF and CKD have been scarcely represented in clinical trial populations. Current concerns affect the practical approach to HF treatment, and, in this context, physicians are frequently hesitant to prescribe and titrate both new and old treatments. Therefore, the extensive application of HF drugs in diverse HF subtypes with numerous comorbidities and different renal dysfunction etiologies remains a controversial matter of discussion. Numerous recently introduced drugs, such as sodium-glucose-linked transporter 2 inhibitors (SGLT2i), constitute a new therapeutic option for patients with HF and CKD. Because of their protective vascular and hormonal actions, the use of these agents may be safely extended to patients with renal dysfunction in the long term. The present review delves into the phenotype of patients with HFpEF and CKD from a pathophysiological perspective, proposing a treatment approach that suggests a practical stepwise algorithm for the proper application of life-saving therapies in clinical practice.

Femtosecond laser LenSx–assisted phacoemulsification of mature intumescent cataract

Background: Phacoemulsification (phaco) of mature intumescent cataract is one of the most difficult to perform anterior eye surgeries. In mature intumescent cataract phaco, the most difficult phase is performing a continuous capsulorhexis which should be as round as possible. The incidence of an anterior capsular tear during capsulorhexis has been reported to range from 0.8 to 5.0% and increases with an increase in cataract density. This is because in dense intumescent cataracts, capsulorhexis tends to extend to the periphery due to high intracapsular pressure. Femtosecond laser–assisted phaco of mature intumescent cataract enables a safe laser-assisted capsulotomy with a substantially reduced risk of intraoperative complications. Because this approach is as yet not widely used in ophthalmology, we aimed to share our experience in the use of femtosecond laser in phacoemulsification of mature and intumescent cataracts. Purpose: To assess the efficacy of femtosecond laser–assisted treatment of mature intumescent cataract. Methods: Sixty-five patients (68 eyes) with mature intumescent senile cataract underwent femtosecond laser-assisted cataract surgery (FLACS) with intraocular lens (IOL) implantation and were involved in this study. Results: In 55 eyes (80.8%), laser capsulotomy of the desired diameter (5.0 mm) was performed completely. In 8 eyes (11.7%), capsular bridges (capsular tissue remnants at the site of laser-assisted cut of the anterior capsule) were seen. In addition, after the laser phase of surgery, 3 eyes (4.4%) showed an irregularly shaped anterior capsular disc due to the failure of the laser to cut through the capsule in several regions. In all study eyes, the IOL was well centered in the bag. Conclusion: In eyes with mature intumescent cataract, it is reasonable to use the femtosecond laser for a safe and accurate anterior capsulorhexis to avoid the severe intraoperative complications (those associated with posterior capsular rapture and vitreous prolapse) that can be seen during manual capsulorhexis.

A safe and successful capsulorhexis technique for the intumescent cataracts; modified two-stage continuous curvilinear capsulorhexis

BackgroundCapsulorhexis is the most important step in intumescent cataract due to the high risk of radial extension of the capsular tear during the cataract surgery. The aim of this study is to present modified the two-stage capsulorhexis technique for intumescent cataract.Materials and methodsThe two-stage capsulorhexis technique was used in this study. A small size capsulorhexis approximately 1.5-2 mm diameter was created in the first stage. Liquefied cortex was aspirated with a 25 G cannula to equalize anterior chamber pressure and intracapsular pressure after the small size capsulorhexis. In the second stage, a 5–6 mm capsulorhexis size was performed for a safe phacoemulsification.ResultsA total of 73 consecutive patients with intumescent cataract were evaluated in this study. There were 39 male cases and 34 female cases. Mean age was 66 years ± 8 (between 53 and 84 years). A well centered complete continuous curvilinear capsulorhexis approximately 5–6 mm size was achieved in 72 of 73 cases (98.6%). Peripheral extension of capsulorhexis occurred in one eye during the second stage capsulorhexis. In this case, the capsule was cut with Vannas scissors and the capsulorhexis was completed. The rest of surgery was continued with a standard procedure and in-the-bag IOL implantation was done.ConclusionsThis technique facilitates the creation of a safe capsulorhexis compared to the one-stage capsulorhexis technique. Surgeons may consider this technique to perform a safe phacoemulsification in the intumescent cataracts.

Perirenal Fat and Kidney Function Deterioration in Patients With Acute Decompensated Heart Failure.

The thick perirenal fat pad can induce high intracapsular pressure and cause compression of the renal vasculature and resultant congestive nephropathy. The current study investigated the association of perirenal fat thickness with kidney dysfunction in patients with acute decompensated heart failure (ADHF). Data from 266 patients hospitalized with ADHF were analyzed. Patients were divided into two groups according to the glomerular filtration rate (GFR) at admission (preserved kidney function [GFR ≥60 mL/min/1.73 m2] and reduced kidney function [GFR <60 mL/min/1.73 m2] groups). Right and left posterior perirenal fat thicknesses were measured using computed tomography, and their average values were calculated. Associated factors with reduced kidney function was assessed by logistic regression model, presenting with odds ratio (OR) and confidence interval (CI). Increasing age (OR, 1.08; 95% CI, 1.04-1.12; p<0.001), diabetes mellitus (OR, 2.46; 95% CI, 1.18-5.12; p<0.017), increased log N-terminal pro-B-type natriuretic peptide (NT-proBNP) (OR, 1.82; 95% CI, 1.32-2.52; p<0.001), and increased average perirenal fat thickness (OR, 1.11; 95% CI, 1.06-1.16; p<0.001) were independently associated with reduced kidney function. In the subgroup analyses, patients over 70 years old, the ratio of mitral-to-mitral annular velocity >15, elevated log NT-proBNP had a significantly higher association with increased perirenal fat thickness with reduced kidney function. Thick perirenal fat pads were independently associated with kidney function deterioration in patients hospitalized with ADHF.

Research on the Relationship Between Meckel's Cavity Shape, Balloon Shape, and Intracapsular Pressure During Percutaneous Balloon Compression

Percutaneous balloon compression is a safe, effective, and minimally invasive therapeutic method for trigeminal neuralgia. Intraoperatively precise compression after the formation of the pear-shaped balloon is the key to the expected effect. In this study, we assessed the relationship between the structure of Meckel's cavity and the shape and intracapsular pressure of the balloon by preoperative magnetic resonance. We respectively analyzed 58 patients with typical trigeminal neuralgia who underwent percutaneous balloon compression surgery in our department. Reconstruction of magnetic resonance imaging 3-dimensional fast imaging employing steady-state acquisition thin-layer scanning sequence was also performed before the operation to analyze the sagittal features of Meckel's cavity. The pressure was recorded continuously when a pear-shaped balloon was forming during the operation. Meanwhile, the balloon height/length (h/l) ratio was measured. The relationship between Meckel's cavity shape, balloon shape, and pressure was analyzed by mentioned parameters. The pain of 57 patients was relieved immediately after the operation, and the effective rate was 98.27% (57 of 58); Recurrence in 2 cases within the median follow-up time (7.5months). Meckel's cavity classification on magnetic resonance showed that the clubbing type, oval type, and flat type accounted for 31.1% (18 of 58), 58.6% (34 of 58), and 10.3% (6 of 58), respectively. The results demonstrated that the intracapsular pressure was low, while the h/l ratio of Meckel's cavity was relatively high. We also found the corresponding pressure results when the ratio was low. However, no significant difference was found between the balloon h/l ratio and Meckel's cavity h/l ratio. Intracapsular pressure of balloon is negatively correlated with the h/l ratio of Meckel's cavity. The individually differentiated formation of the pear-shaped balloon has little correlation with the sagittal shape of Meckel's cavity.

Effect of Intracapsular Pressure on Decompression Effectiveness

The objective of this research was to analyse the correlation between intracapsular pressure and shrinkage rate of cystic lesion volume at different time points after decompression and to evaluate the relationship between the concentration of interleukin-1α (IL-1α) in cystic fluid and intracapsular pressure. Fifty patients with jaw cystic lesions who underwent decompression were included. We measured the intracapsular pressure and IL-1α concentration in the cyst fluid. Moreover, we calculated the rate of shrinkage (RS) of cystic cavity volume at different time points. In addition, data on age, sex, preoperative cystic cavity volume, and lesion location were collected. Linear correlation analysis and variance analysis were used for statistical analysis. Fastest volume decline was observed between 0 and 3 months after surgery; the average RS0-3 was 45.71%. RS3-6 presented the second-fastest volume decline, with an average of 17.46%, and RS6-12 presented the slowest volume decline, with an average of 3.933%. A statistically significant difference in RS was observed amongst the 3 time points (P < .0001). RS0-3 was negatively correlated with intracapsular pressure (r=-0.6326, n=50, P < .0001). A negative correlation between the preoperative cystic cavity volume and intracapsular pressure (r=-0.6384, n=50, P < .001) was also observed. A significant positive correlation was observed between preoperative cystic cavity volume and RS0-3 (r=0.611, n=50, P < .0001). Moreover, a significant positive correlation was observed between the intracapsular pressure and IL-1α concentration in the cystic fluid (r=0.03477, n=50, P < .0001). Intracapsular pressure and the preoperative volume were the factors that affected the RS during the first 3 months after surgery. Therefore, the effectiveness of decompression can be evaluated by the intracapsular pressure and preoperative volume.

Finite Element Modeling of Planus and Rectus Foot Types for the Study of First Metatarsophalangeal and First Metatarsocuneiform Joint Contact Mechanics.

The foot is a highly complex biomechanical system for which finite element (FE) modeling has been used to evaluate its loading environment. However, there is limited knowledge of first metatarsophalangeal (MTP) and first metatarsocuneiform (MTC) joint contact mechanics. Our goal was to develop a framework for FE modeling of the medial forefoot which could accurately predict experimental measurements of first MTP and first MTC joint loading. Simulations of planus and rectus foot types were conducted for midstance of gait. A custom-built force-controlled cadaveric test-rig was used to derive intracapsular pressure sensor measurements of contact pressure, force, and area during quasi-static loading. The FE model was driven under the same boundary and loading conditions as the cadaver. Mesh sensitivity analyses and best-fit calibrations of moduli for first MTP and first MTC joint cartilage were performed. Consistent with previous experimental research, a lower compressive modulus was best-fit to the first MTP compared to first MTC joint at 10 MPa and 20 MPa, respectively. Mean errors in contact pressures, forces, and areas were 24%, 4%, and 40% at the first MTP joint and 23%, 12%, and 19% at the first MTC joint, respectively. The present developmental framework may provide a basis for future modeling of first MTP and first MTC joint contact mechanics. This study acts as a precursor to validation of realistic physiological loading across gait to investigate joint loading, foot type biomechanics, and surgical interventions of the medial forefoot.

Normal range of motion at the hip show different pressure behavior in the lateral and acetabular compartments: a cadaveric investigation

PurposeThe techniques used previously to assess intracapsular pressures did not allow the assessment of pressure variations in both compartments throughout the entire range of motion without puncturing the capsular tissue. Our hypothesis was that the intra-capsular pressure would be different in the lateral and acetabular compartment depending on the movement assessed.MethodsEight hip joints from four cadaveric specimens (78.5 ± 7.9 years) were assessed using intra-osseous tunnels reaching the lateral and acetabular compartments. Using injector adaptors, 2.7 ml of liquid were inserted in both compartments to simulate synovial liquid. Optic pressure transducers were used to measure pressure variations. We manually performed hip adduction, abduction, extension, flexion and internal rotation at 90° of flexion.ResultsHip extension and internal rotation show the highest intra-capsular pressures in the lateral compartment with increases of 20.56 ± 19.29 and 19.27 ± 18.96 mmHg, respectively. Hip abduction and hip internal rotation showed depressurisations of − 16.86 ± 18.01 and − 31.88 ± 30.71 mmHg in the acetabular compartment, respectively. The pressures measured in the lateral compartment and in the acetabular compartment were significantly (P < 0.05) different for the hip abduction, 90° of flexion and internal rotation. Pressure variations showed that maximum intracapsular fluid pressures in the lateral compartment occur at maximum range of motion for all movements.ConclusionAs an increase in pressure may produce hip pain, clinician should assess pain at maximum range of motion in the lateral compartment. The pressure measured in the acetabular compartment vary depending on the hip position. The movements assessed are used in clinical practice to evaluate hip integrity and might bring pain. The pressure variations throughout the entire range of motion are a relevant information during hip clinical assessment and might help clinicians to better understand the manifestations of pain.

Effects of Botulinum Toxin A on the Blood Flow in Expanded Rat Skin

Background Poor blood supply can easily lead to expander extrusion and necrosis at the distal expanded flap. Botulinum toxin A (BTX-A) has been previously found to improve pedicled flap blood flow perfusion, but its effects on the blood supply of expanded skin remain unclear. Therefore, this study aimed to evaluate the effects of BTX-A on blood flow perfusion during and after expansion. Methods Eighteen Sprague-Dawley rats were randomly divided into a BTX-A group and a control group. BTX-A or normal saline was injected intradermally into the marked skin on the back immediately. Then expanders were implanted in the rats. One week later, inflation of the expander with normal saline was started and performed twice a week to reach an intracapsular pressure of 8 kPa. The skin blood flow was measured before each injection. After 4 weeks of expansion, the sample was harvested for histological staining to measure the diameter and density of blood vessels; meanwhile, a 2 cm× 8 cm expanded random flap was elevated and sutured in situ. Blood flow perfusion and flap survival were observed. Results Compared with the control group, the BTX-A group had more blood flow, a larger blood vessel diameter, and higher blood vessel density in the expanded skin. Additionally, the flap of the BTX-A group had good blood flow perfusion and a high proportion of flap survival area within 7 days after expanded flap transfer. Data were analyzed using an independent t-test. Conclusion Pre-surgical BTX-A treatment may increase angiogenesis and vasodilatation, with subsequent blood perfusion elevation during and after expansion, and obtain a greater proportion of survival area of the transferred expanded flap.

Electron microscopy analysis of femtosecond laser-assisted capsulotomy before and after lens fragmentation

Studying anterior lens capsule cutting edge profiles from femtosecond laser-assisted capsulotomy procedures performed before and after lens fragmentation. Twenty eyes (10 patients) with age-related cataract underwent femtosecond laser-assisted surgery (FLACS) using the Ziemer Z8 platform. First step of laser surgery was either capsulotomy (group first) or fragmentation (group second). One eye of each patient was assigned randomly, the second eye treated with the different sequence of procedures. After anterior capsule removal, tissue was fixed in cacodylate-buffered solution and cutting-edge profiles were analysed using scanning electron microscopy (SEM). All cases had cataract grade 2 and 3 based on LOCS III grading. SEM analysis showed more smooth edges in the first group, especially in cases with pseudoexfoliation (P = 0.037); more tags and bridges and a significant number of staggered cutting patterns (7 out of 10 cases) in the second group. All cases evolved the same microgroves with “valleys and mountains “ as signs of the photodisruption process. Femtosecond laser capsulotomy should be performed before lens fragmentation minimizing the rate of cutting errors. Especially in eyes with advanced cataract, as intracapsular pressure may increase due to lens fragmentation without anterior capsular opening.

Intracapsular pressures in the flexion-abduction-external rotation and flexion-adduction-internal rotation tests and their comparison with classic hip range of motion: A cadaveric assessment

BackgroundFlexion-Abduction-External-Rotation and Flexion-Adduction-Internal-Rotation tests are used to reproduce pain at the hip during clinical assessment. As pain can be elicited by high intracapsular pressure, no information has been provided regarding intracapsular pressure during these pain provocative tests.MethodsEight hip joints from four cadaveric specimens (78.5 ± 7.9 years) were assessed using intra-osseous tunnels reaching the lateral and acetabular compartments. To simulate synovial liquid, 2.7 ml of liquid were inserted in both compartments using adaptor injectors. Optic pressure transducers were used to measure pressure variations. Pressures were compared between compartments in each test and between tests for each compartment. Both tests were compared with uniplanar movements.FindingsThe Flexion-Adduction-Internal-Rotation test showed a significant difference between pressure measured in the lateral (27.17 ± 42.63 mmHg) and acetabular compartment (−26.80 ± 29.26 mmHg) (P < 0.006). The pressure measured in the lateral compartment during the Flexion-Adduction-Internal-Rotation test (27.17 ± 42.63 mmHg) was significantly higher than in the Flexion-Abduction-External-Rotation test (−8.09 ± 15.09 mmHg) (P < 0.010). The pressure measured in the lateral compartment in the Flexion-Abduction-External-Rotation test was significantly lower than during internal rotation (P = 0.011) and extension (P = 0.006).InterpretationHigh intracapsular pressure is correlated with greater pain at the hip. Clinicians should assess pain with caution during the Flexion-Adduction-Internal-Rotation test as this test showed high intracapsular pressures in the lateral compartment. The Flexion-Abduction-External-Rotation is not influenced by high intra-capsular pressures.

Intracapsular pressure in children with septic arthritis of the hip.

Elevated intracapsular pressure in the hip causes occlusion of the retinacular vessels and may result in avascular necrosis of the proximal femoral epiphysis (ANPFE) and growth disturbances. Our goal is to study intraarticular pressure in children with septic arthritis of the hip and its potential correlation with body weight, systemic blood pressure and the volume of synovial fluid aspirated from the joint. Thirteen septic arthritis of the hip were studied. Inclusion criteria: pain, limping, fever, leukocytosis, elevated C-reactive protein and ultrasonographic effusion >5 mm. Traumatic, inflammatory, rheumatic or tumoral origin were excluded. Mean age was 3.7 years. Girls were 58%. Mean time to articular drainage was 15 h. Arthrocentesis was performed. An STIC self-calibrating monitoring system with an error of ±1 mmHg was used. Measurements were taken: intracapsular pressure, volume of fluid aspirated, systolic and diastolic pressures and weight. Follow-up was 6.3 years. Descriptive and nonparametric tests were performed: U Mann-Whitney and Kruskal-Wallis. Statistical significance was P <0.05. Mean intracapsular pressure was 50.5 mmHg; fluid aspirated was 2.9 ml; systolic and diastolic pressures were 107.5 and 44.3 mmHg, respectively; weight was 16.2 kg. Intracapsular pressure exceeded 30 mmHg in eight children (61.5%) and was lower than 50 mmHg in 73%. Variables studied had no significance on intracapsular pressure. Complications: coxa magna in three patients (23%) and Harris lines in three (23%). Surgical drainage of septic arthritis of hip must be performed urgently, within the first 24 hours, to reduce the time with high intracapsular pressure and to avoid risk of ANPFE.

Clinical study for preoperative traction on impact of osteonecrosis of femoral head in patients with femoral neck fractures

To explore the impact of preoperative traction on the osteonecrosis of the femoral head (ONFH) in patients with femoral neck fractures. Between February 2013 and May 2016, 120 patients with femoral neck fractures, who were treated with screw fixation, were collected. Sixty patients with fractures of Garden type Ⅰ and Ⅱ were non-displaced fracture group; 60 cases with fractures of Garden type Ⅲ and Ⅳ were displaced fracture group. The patients in 2 groups were randomly divided into traction and non-traction subgroups ( n=30). There was no significant difference in gender, age, injury mechanism, damage side, the time from injury to operation, and fracture classification between 2 subgroups ( P>0.05). Intracapsular pressure was recorded before operation. The quality of fracture reduction and the satisfaction ratio of screw implant were evaluated during operation. Visual analogue scale (VAS), Harris score, joint mobility, and the incidence of ONFH would be evaluated at 6 months, 1 year, and 2 years after operation. All incisions of 2 groups healed by first intention after operation. There was no infection or deep vein thrombosis of lower extremity. All patients were followed up 2 years. In displaced and non-displaced fracture groups, the intracapsular pressure of traction subgroups were higher than that of non-traction group ( P<0.05); the differences of the quality of fracture reduction and the satisfaction ratio of screw implant were not significant ( P>0.05) between 2 subgroups. At 6 months, 1 year, and 2 years after operation, VAS scores were higher in traction subgroup than in non-traction subgroup ( P<0.05); and the joint mobility and Harris scores were lower in traction subgroup than in non-traction subgroup ( P<0.05). X-ray films showed all fractures healed. Except for the non-displaced group at 6 months, the incidences of ONFH were higher in traction subgroup than in non-traction subgroup at other time points ( P< 0.05). Preoperative traction may increase the risk of ONFH, which can increase the intracapsular pressure and affect the blood supply of femoral head.

Changes in intraarticular pressure on the blood supply in the retinaculum of the femoral neck

BackgroundThis study aimed to analyze the effects of intracapsular pressure (IAP) on blood flow in the femur after a femoral neck fracture. MethodsFour simplified vascular models were used to measure the effect of vessel length on arterial blood flow in 10 New Zealand white rabbits. Ten models were evaluated under 10 different blood pressures. FindingsIAP increased following fracture of the femoral neck, and deformation had the greatest potential effect on blood flow in the retinacular artery. When blood pressure was fixed at 60 mm Hg, an increase in IAP caused a reduction in blood flow. When the IAP was relatively high (above 60 mm Hg), and higher than the blood pressure, blood flow continued to drop as intracapsular pressure increased. Shortening of blood vessels had no significant effect on blood supply. However, the p-value was uniformly significant (<0.05) when stretched and twisted blood vessels were compared with normal blood vessels. InterpretationThe results of computational fluid-structure interaction similarly indicated that a smaller blood vessel diameter and twisted blood vessels will result in decreased flow velocity when IAP increases. This study also revealed a close relationship between IAP and the hip joint's position and traction.

Increased Hip Intracapsular Pressure Decreases Perfusion of the Capital Femoral Epiphysis in a Skeletally Immature Porcine Model.

Increased intracapsular hip pressure is thought to be one of the possible etiologies of femoral head avascular necrosis after intra-articular proximal femoral fractures or acute slipped capital femoral epiphysis. The purpose of this study was to evaluate the relationship between intra-articular hip pressure (IAP) and epiphyseal perfusion pressure (EPP), and its dependency on skeletal maturity using a porcine model. Seven female Yorkshire-hybrid pigs were used to study the direct relationship between IAP and EPP. A needle inserted into the capsule provided both IAP monitoring and saline infiltration until IAP was above mean arterial pressure (MAP). Video simultaneously documented IAP, EPP, MAP. Parameters for all trials in each hip were averaged and compared between the 2 age groups. Significance was P<0.05. Four young hips (in pigs 10.3±1.0 wk, 27.4±2.0 kg) and 5 older hips (21.1±0.1 wk, 89.4±7.1 kg) were studied. There was no significant difference in the MAP (50.0±11.8 and 55.5±7.0 mm Hg respectively, P=0.411) between the 2 age groups. In the older hips, biphasic EPP persisted despite increasing IAP to an average of 177 mm Hg over MAP. In the young pigs, the biphasic EPP waveform ceased with increased IAP to an average of 28 mm Hg over MAP. Biphasic waveforms returned once IAP fell to an average of 5 mm Hg over MAP. Increased IAP resulted in tamponade of epiphyseal perfusion in the young, but not in the older hips. An intact physis may preclude intraosseous metaphyseal vessels from penetrating the epiphysis, leaving it vulnerable to retinacular artery tamponade. The IAP and EPP relationship has direct clinical practice implications. Hip capsulotomy and decompression in young patients with intra-articular proximal femoral fractures and increased intracapsular pressure may decrease avascular necrosis risk.

The safety and efficacy of phaco-sleeve irrigation-assisted hydrodissection during femtosecond laser-assisted cataract surgery.

Femtosecond laser-assisted cataract surgery (FLACS) changes the intraoperative environment due to the generation of intracapsular gas that induces a high intracapsular volume. Manual hydrodissection (mH) may induce high intracapsular pressure (ICP) and additional intracapsular volume, thereby leading to capsular block syndrome (CBS). Since the phaco-sleeve irrigation-assisted hydrodissection (iH) technique is used to initially groove and split the lens and remove the intracapsular gas, this can reduce the intracapsular volume while bypassing the intracapsular lens prior to the hydrodissection. As iH uses the phaco tip to intentionally vacuum the intraocular fluid for use in inducing the irrigation jet from the sleeve side holes, the ICP cannot surpass the set irrigation pressure, thereby avoiding CBS. Using this technique, we performed FLACS without CBS in 310 cataract eyes. Our findings suggest that the iH technique may be beneficial for patients by preventing CBS during FLACS.

Neglected traumatic hip dislocation: Influence of the increased intracapsular pressure.

AIMTo investigate that the increased intracapsular pressure, during the delay period, can interrupt the blood flow to the femoral head.METHODSAn observational retrospective study included a group of 17 patients with traumatic hip dislocation, their ages at time of injury averaged 26 (range from 3 to 70) years. Outcomes were assessed clinically and radiographically at a period averaged 11.5 (range from 4 to 20) years.RESULTSMinor trauma caused dislocation in seven and severe trauma in ten patients. All dislocations were posterior, six isolated dislocation and 11 were associated with other injuries. The negligence period averaged 2.5 (ranged from 1 to 4) d. At the latest visit, the radiography revealed normal hip in 11 and avascular necrosis (AVN) in six patients. Clinically, eight patients were rated as excellent, three good, three fair and three poor.CONCLUSIONWe believe the factors that contribute to increased intracapsular pressure also increase the influence of delayed reduction toward the development of AVN.

Vascularity of femoral head and its assessment after femoral neck fractures

Femoral neck fracture has an annual incidence of 1 per 1000 population; in young patients, functional prognosis is not good due to risk of osteonecrosis. Femoral head vascularity is mostly contributed by retinacular vessels and lateral epiphyseal artery. The vascular impact is due to displacement, interrupting retinacular vessel, interrupting ligament teres vascularization, and increased intracapsular pressure, producing a tamponade effect leading to osteonecrosis. This study reviewed the different methods of assessment of femoral head vascularity after femoral neck fractures. There are many techniques for the assessment of residual femoral head vascularity after femoral neck fractures and for the assessment of post-traumatic osteonecrosis risk. Some invasive techniques are superselective angiography, intraosseous oxygen pressure measurement, or Doppler-laser hemodynamic measurement; others are noninvasive scintigraphy and conventional or dynamic magnetic resonance imaging (MRI). The future seems to lie with dynamic MRI, which gives new classification of femoral neck fractures, based on a noninvasive assessment of femoral head vascularity.

Association between kidney intracapsular pressure and ultrasound elastography

BackgroundKidney congestion is a common pathophysiologic pathway of acute kidney injury (AKI) in sepsis and heart failure. There is no noninvasive tool to measure kidney intracapsular pressure (KIP) directly.MethodsWe evaluated the correlation of KIP with kidney elasticity measured by ultrasound surface wave elastography (USWE). We directly measured transcatheter KIP in three pigs at baseline and after bolus infusion of normal saline, norepinephrine, vasopressin, dopamine, and fenoldopam; infiltration of 2-L peritoneal dialysis solution in the intra-abdominal space; and venous, arterial, and ureteral clamping. KIP was compared with USWE wave speed.ResultsOnly intra-abdominal installation of peritoneal dialysis fluid was associated with significant change in KIP (mean (95% CI) increase, 3.7 (3.2–4.2)] mmHg; P < .001). Although intraperitoneal pressure and KIP did not differ under any experimental condition, bladder pressure was consistently and significantly greater than KIP under all circumstances (mean (95% CI) bladder pressure vs. KIP, 3.8 (2.9–4.) mmHg; P < .001). USWE wave speed significantly correlated with KIP (adjusted coefficient of determination, 0.71; P < .001). Estimate (95% CI) USWE speed for KIP prediction stayed significant after adjustment for KIP hypertension (−0.8 (− 1.4 to − 0.2) m/s; P = .008) whereas systolic and diastolic blood pressures were not significant predictors of KIP.ConclusionsIn a pilot study of the swine model, we found ultrasound surface wave elastography speed is significantly correlated with transcatheter measurement of kidney intracapsular and intra-abdominal pressures, while bladder pressure overestimated kidney intracapsular pressure.