Increased pulsatility index of the basilar artery is a risk factor for neurological deterioration after stroke: a case control study.

BACKGROUND: Higher pulsatility of the middle cerebral artery (MCA) is known to be associated with stroke progression. We investigated whether pulsatility index (PI) of the basilar artery (BA) can predict neurological deterioration (ND) after acute cerebral infarction. METHODS: A total of 708 consecutive patients with acute ischemic stroke who had undergone transcranial Doppler (TCD) ultrasonography were included. ND was defined as an increase in the National Institutes of Health Stroke Scale scores by two or more points after admission. The patients were categorized into quartiles according to BA PI. Multivariable logistic regression analysis was performed to examine whether BA PI is independently associated with ND. RESULTS: BA PI was well correlated with the right (n = 474, r2 = 0.573, P < 0.001) by Pearson correlation analysis although MCA PI could not be measured from right MCA (n = 234, 33.05%) and left MCA (n = 252, 35.59%) by TCD owing to insufficient temporal bone window. Multivariable logistic regression analysis including age, sex, cerebral atherosclerosis burden, National Institutes of Health Stroke Scale at admission, and the proportion of patients with current smoking status, hypertension, diabetes mellitus, atrial fibrillation revealed that the higher BA PI (odds ratio, 3.28; confidence interval, 1.07-10.17; P = 0.038) was independently associated with ND. CONCLUSIONS: BA PI, which would be identified regardless of temporal window, could predict ND among acute stroke patients.

Numerical investigation of urethra flow characteristics in benign prostatic hyperplasia.

BACKGROUND AND OBJECTIVE: Conventional practice includes a limited depiction of urethral pressure and flows based on fragmented gross clinical observations. However, with technological advancements in simulations, computational fluid dynamics (CFD) can provide an alternative approach to predict the bladder pressure with a concordant quantitative flow field in the urethra. Thus, this study aims to comprehensively analyze the urine flow characteristics in various urethra models using simulations. METHODS: Three-dimensional urethra models were constructed for seven specific subjects based on clinical radiographs. Simulations with Reynolds averaged Navier-Stokes model were performed to quantitatively investigate the urine flow under various volume flow rate of voided urine. RESULTS: Under benign prostatic hyperplasia, the spindle shape of the prostatic urethra (PRU) generates wake flow. The wake flow was also observed in several regions downstream of the PRU, depending on the urethra shape. This wake flow resulted in total pressure loss and urinary tract dysfunction. When comparing pre- and post-operative urethra models, the bladder pressure decreased by 14.98% in P04 and 4.67% in P06. Thus, we identified variability between surgical results of patients. The bladder pressure according to the volume flow rate of voided urine was investigated using simulations and the theoretical consideration based on hydrodynamics. In theoretical consideration, the bladder pressure was expressed as a second-order polynomial for volume flow rate. These results concur with the simulation results. CONCLUSION: Numerical simulation can describe the urine flow field in the urethra, providing the possibility to predict the bladder pressure without requiring painful, invasive interventions, such as cystoscopy. Furthermore, effective treatments to improve urination function can be formulated to be patient-specific, by detecting causes and problem regions based on quantitative analysis and predicting post-surgical outcomes.

Distal Radius Fractures: Does Obesity Affect Fracture Pattern, Treatment, and Functional Outcomes?

BACKGROUND: Distal radius fractures (DRFs) are 16% of fractures treated by orthopedic surgeons. Obesity's influence on DRF complexity has not been studied. This study was undertaken to determine if body mass index (BMI) affects DRF pattern, treatment, and functional outcomes. METHODS: Part 1 was a retrospective review of patients who sustained a DRF after a fall from standing height with no prior reduction or treatment. Radiographs were classified as "simple" or "complex." Part 2 consisted of contacting patients from Part 1 and obtaining a Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score. Retrospective review also identified patients who failed initial nonoperative treatment. Fracture pattern, failure of nonoperative treatment, and QuickDASH scores were compared with BMI at the time of injury. RESULTS: For Part 1, 130 patients (132 wrists) were identified. Average age was 57 years, 77% were female, and average BMI was 28.2 kg/m2. Each point increase in BMI increased the chance of having a complex DRF (odds ratio = 1.07). Part 2 identified 50 patients who completed a QuickDASH at an average of 4.6 years after injury. Those with a BMI <25 kg/m2 (n = 15) had an average QuickDASH score of 37; patients with a BMI ≥25 kg/m2 (n = 35) had an average QuickDASH score of 18. Increasing BMI was suggestive of a lower QuickDASH score ( P = .08). No significant difference was found with respect to BMI and failure of nonoperative treatment. CONCLUSIONS: A higher BMI increases the odds of a complex DRF. Despite more complex fractures, overweight patients may experience less disability after sustaining a DRF.

Numerical study to evaluate the effect of a surface-based sensor on arterial tonometry.

Arterial tonometry is a widely used non-invasive blood pressure measurement method. In contrast to the cuff-based method, it is possible to obtain a continuous pressure profile with respect to systolic and diastolic pressures using this method. However, due to a requirement of arterial tonometry-that a sensor needs to be placed directly above a blood vessel-placement error is inevitable if the measurement device is only capable of measuring local regions. This study assumed that the plate sensor is flexible, thus reducing the placement error. We investigated the pressure distribution along the wrist surface rather than the local region through the contact simulation between the flexible plate sensor and the wrist. As a result, we concluded that there is a unique pressure distribution for any specific wrist, regardless of the length and position of the plate, and that it is possible to measure the blood pressure using the response at the wrist surface to the pressure inside the radial artery.

Numerical Investigation of Vasospasm Detection by Extracranial Blood Velocity Ratios.

BACKGROUND: Early diagnosis of vasospasm following subarachnoid hemorrhage can prevent cerebral ischemia and improve neurological outcomes. This study numerically evaluates the relevance of extracranial blood velocity indices to detect vasospasm. METHODS: A numerical model of cerebral blood flow was used to evaluate the hemodynamics associated with anterior and posterior vasospasm under normal and impaired cerebral autoregulation conditions. Extracranial blood velocities at the carotid and vertebral arteries and their ratios between ipsilateral and contralateral, anterior and posterior, and downstream and upstream arteries were monitored during vasospasm progression. RESULTS: For current clinical indices that track blood velocities at vasospastic arterial segments using transcranial Doppler (TCD), we observed that velocities increased initially and then decreased with vasospasm progression. This nonmonotonic behavior can lead to false-negative decisions in moderate to severe vasospasm. Alternatively, volumetric flow decreased monotonically at the affected arteries, leading to blood velocities upstream of the vasospastic artery also decreasing monotonically. Based on this principle, we demonstrate that velocity ratios between the carotid and vertebral arteries may better identify moderate to severe vasospasm and improve sensitivity and specificity of vasospasm detection. CONCLUSION: The velocity indices proposed in this study may enable new or improved noninvasive diagnosis of vasospasm using extracranial Doppler ultrasound. Compared to current clinical indices, the new indices may improve the handling of (1) scenarios of severe vasospasm or impaired cerebral autoregulation, (2) systemic changes in blood pressure and cardiac output, (3) vasospasm occurring in arteries distal to the cerebral circle region, and (4) cases with insufficient acoustic bone window for TCD. The results provide a concrete basis for future clinical evaluation of extracranial indices for vasospasm detection.

A Coupled Lumped-Parameter and Distributed Network Model for Cerebral Pulse-Wave Hemodynamics.

The cerebral circulation is unique in its ability to maintain blood flow to the brain under widely varying physiologic conditions. Incorporating this autoregulatory response is necessary for cerebral blood flow (CBF) modeling, as well as investigations into pathological conditions. We discuss a one-dimensional (1D) nonlinear model of blood flow in the cerebral arteries coupled to autoregulatory lumped-parameter (LP) networks. The LP networks incorporate intracranial pressure (ICP), cerebrospinal fluid (CSF), and cortical collateral blood flow models. The overall model is used to evaluate changes in CBF due to occlusions in the middle cerebral artery (MCA) and common carotid artery (CCA). Velocity waveforms at the CCA and internal carotid artery (ICA) were examined prior and post MCA occlusion. Evident waveform changes due to the occlusion were observed, providing insight into cerebral vasospasm monitoring by morphological changes of the velocity or pressure waveforms. The role of modeling of collateral blood flows through cortical pathways and communicating arteries was also studied. When the MCA was occluded, the cortical collateral flow had an important compensatory role, whereas the communicating arteries in the circle of Willis (CoW) became more important when the CCA was occluded. To validate the model, simulations were conducted to reproduce a clinical test to assess dynamic autoregulatory function, and results demonstrated agreement with published measurements.

Radiographic evaluation of the distal radius using two novel biplanar "pitch-and-roll" views: a preliminary cadaveric study.

This study's objective was to compare the use of two biplanar angled radiographs versus standard posterioanterior (PA) and lateral radiographs in determining preservation of the articular space with regard to pin placement in the distal radius. Various combinations of inclination (pitch) and clockwise/counterclockwise rotation (roll) were used to determine the best view of the distal radius articular surface. Optimum visualization of the articular surface presented at 12 degrees inclination plus 15 degrees counterclockwise rotation for the PA view and 22 degrees inclination and 15 degrees counterclockwise rotation for the lateral view. Ten cadaveric forearms were dissected, and ten Kirschner wires (K-wires) were placed at specific surfaces of the distal radius. Each K-wire was countersunk 2 mm below the chondral surface so all K-wires resided within the subchondral bone. Each forearm was radiographed in four views; PA, lateral, pitch-and-roll PA (PR-PA), and pitch-and-roll lateral (PR-lateral). Four blinded reviewers evaluated the radiographs and marked whether they were certain, relatively certain, or uncertain that the K-wires did not penetrate into the articular space. Reviewers demonstrated significantly less uncertainty about intraarticular penetration (p < 0.005) with both the PR-PA and PR-lateral views compared with standard PA and lateral views. The biconcave nature of the distal radius makes it extremely difficult to visualize placement of hardware with respect to the articular surface using standard radiographs. The use of PR-PA and PR-lateral views significantly improves the surgeon's ability to judge the position of hardware in the distal radius compared to standard radiographic views, thus allowing for more meaningful clinical decision in post-operative radiographs.

Long-term results of lateral calcaneal artery flap for hindfoot reconstruction.

The purpose of the present study was to analyze our long-term results of lateral calcaneal artery flap transfer for hindfoot reconstruction. A total of four patients (average age, 48 years) underwent lateral calcaneal artery flap transfer. The etiologies were heat injury of the lateral malleolus in one patient and skin necrosis over the Achilles tendon attachment site in three patients due to displaced calcaneal fracture, pyogenic tendinitis of the Achilles tendon, and vascular insufficiency of the wound after Achilles tendon surgery in a patient with Werner syndrome, respectively. The defect sizes ranged from 2 x 2 cm to 4 x 4 cm, and all of the patients had bone or tendon exposure. All of the flaps survived completely without any problems. The donor sites were closed by full-thickness skin grafts. Postoperative complications included delayed wound healing in one patient and transient restriction of ankle motion in another patient. No painful neuroma of the sural nerve was recorded. No recurrence of ulcers at the shoe-contacting area of the flaps was noted. Therefore, lateral calcaneal artery flap transfer is useful for reconstruction of skin and soft tissue defects with bone or tendon exposure over the calcaneus or lateral malleolus.

Understanding wrist instabilities.

The wrist function is to position the hand optimally for specific tasks. To do so, the wrist must have a large arc of motion while maintaining its stability. The traditional row theory, and the columnar theory were developed to explain how the columns and rows affect wrist motion and stability. The paper discuses normal and pathologic interaction between carpal bones and their position. All kinds of wrist instability are precisely described. The article summarizes with some possibilities of treatment.

Use of arthroscopy in wrist instabilities.

Wrist arthroscopy is one of the most important tools in diagnosis of wrist pathologies. This invasive method of diagnosis can provide us a true view of cartilage, ligamentous stability giving also a possibility of dynamic probing. Diagnosis is a first step of the arthroscopy. Then some treatment procedures can be performed. Wrist arthroscopy has emerged as the gold standard for accurate diagnosis of wrist instabilities and has shown promise for some therapeutic values. Many other therapeutic methods are being tested as techniques and equipment are being continuously refined, and its indications are broadening.

Sterility of surgical site marking.

BACKGROUND: Over the past decade, wrong-site surgery has been a popular topic of discussion, not only in medical and legal journals but also in the mainstream press. Marking of the surgical site according to the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) Universal Protocol was implemented at our institution to help reduce the number of wrong-site operations. In this study, we determined whether marking of the site affected the sterility of the surgical field. METHODS: The study included twenty volunteers. The right forearm was used as the experimental (marked) arm and the left forearm, as the control arm. The experimental forearms were marked with a surgical marker as described by the protocol. Both upper extremities were then sterilized from the antecubital fossa to the phalanges with a 7.5% povidone-iodine scrub followed by the application of a 10% povidone-iodine paint. Swabs were used to obtain samples from the experimental and control arms as well as from the marker and were sent for microbiological culture and analysis. RESULTS: No growth was seen in the cultures of the swabs used on the experimental or control arms or on the marking pens. CONCLUSIONS: Preoperative marking of surgical sites in accordance with the JCAHO Universal Protocol did not affect the sterility of the surgical field, a finding that provides support for the safety of surgical site marking.

Anatomical basis for a vascular pedicled island flap from the dorsal area of the wrist.

We explored the cutaneous vascularity of the dorsal wrist area to examine the possibility of using reverse island flaps from this area for reconstruction of the hands and fingers. Four dominant arterial branches including the dorsal branches of the ulnar and radial arteries and terminal branches of the anterior and posterior interosseous arteries, which supplied the dorsal skin over the extensor retinaculum, were explored. The location, number, and diameter of skin perforators from these arteries were examined. The dorsal branches of the radial and ulnar arteries that passed along the dorsal cutaneous nerves gave off 2-4 skin perforators (diameter 0.1-0.2 mm) at the level of the carpal bone and always connected distally to perforating arteries from the palmar arterial system at the metacarpal head. Skin perforators from the anterior and posterior interosseous arteries were found passing through the extensor retinaculum in the second and third and fifth and sixth intercompartmental areas. The terminal branches of the anterior and posterior interosseous arteries always continued to the dorsal carpal arch, and lay over the distal carpal row. It may be anatomically possible to raise two different island flaps from the dorsum of the wrist.

Wrist kinetics after scapholunate dissociation: the effect of scapholunate interosseous ligament injury and persistent scapholunate gaps.

The purpose of this study was to investigate the effects of cutting of the scapholunate interosseous ligament (SLIL) and persistent widening of the scapholunate (SL) joint on changes in moment arms of the principal wrist motor tendons. In seven fresh frozen cadaveric upper extremities, excursions of the extensor carpi radialis longus (ECRL) and brevis (ECRB), extensor carpi ulnaris (ECU), flexor carpi radialis (FCR), and flexor carpi ulnaris (FCU) were recorded simultaneously with wrist joint angulation during wrist flexion-extension and radioulnar deviation. Tendon excursions were measured in intact wrists, then in the wrists with complete SLIL sectioning and in those with moderate or severe persistent SL joint widening. The data were converted to moment arms of the tendons. The results showed that moment arms of the ECRL and ECRB tendons after SLIL sectioning were, respectively, 110+/-6% and 105+/-3% of those in the intact wrist. In the wrists with moderate or severe SL joint widening, moment arms of the flexors significantly increased (P < 0.01 and P < 0.001, respectively). During radioulnar deviation, moment arms of the ECRL, ECRB, ECU, and FCU tendons decreased after SLIL sectioning and the SL joint widening. However, moment arms of the FCR tendon significantly increased 122+/-23% after the SLIL section, 133+/-28% after the moderate SL joint widening, and 138+/-24% after the severe SL joint widening compared with those of the intact wrists. This study demonstrated that integrity of the SLIL and appropriate SL joint space are important for mechanics of wrist motor tendons. Loss of integrity of the SLIL and persistent SL joint widening increase mechanical effects of the radial side wrist motor tendons, which may contribute to the pathomechanics of scaphoid malrotation, scapholunate advanced collapse, and early osteoarthritis in the radioscaphoid joint interface seen in SL dissociation. The results also suggest that reduction of the displaced SL joint is imperative to the recovery of wrist kinetics after SL dissociation.

Anatomy of the ulnar artery as it relates to the transverse carpal ligament.

The anatomic relationship between the ulnar artery and transverse carpal ligament (TCL) as an aid in planning for minimally invasive carpal tunnel surgery was investigated. The anatomic course of the ulnar artery and its branches toward the TCL and the location of the median nerve were determined in 24 fresh cadaver hands perfused with a silicone compound. The ulnar artery coursed from 7 mm ulnar to 2 mm radial to the hook of hamate. The average distance between the superficial palmar arch and the distal margin of the TCL was 12 mm as measured along the flexor tendon of the ring finger. The location of the median nerve extended an average of 11 mm radial to the hook of hamate. A small arterial branch (average diameter, 0.7 mm) from the ulnar artery ran transversely just over the TCL in 6 of the 24 specimens. This branch was consistently located within 15 mm proximal to the TCL distal margin. These and other microscopic observations indicated that transecting the ligament at approximately 5 mm radial to the radial margin of the hook of hamate may minimize postoperative bleeding and avoid iatrogenic vascular and neural injury.