Alternate Occlusion Research Articles

Сравнительный анализ эффективности формирования бинокулярного зрения у пациентов с врожденной эзотропией после проведения хирургического лечения с помощью призматической коррекции и ортоптического лечения

Purpose. To carry out a comparative analysis of the effectiveness of the formation of binocular vision in patients with congenital esotropia after surgical treatment using prismatic correction and orthoptic treatment. Material and methods. The study included 30 patients who, depending on the tactics of treatment, were divided into 2 groups. The first (main) – 15 patients who underwent postoperative prismatic correction of the angle of deviation using Fresnel prisms. The second (control) – 15 patients who underwent postoperative orthoptic treatment (alternate occlusion, Chermak illumination, orthoptic treatment on the synoptophore). Results. In the main group, there was a statistically significant increase in the frequency of binocular (p = 0.041) and stereo vision (p = 0.013). In the control group, these indicators were also significantly improved (p = 0.134; p = 0.134, respectively). Significant differences between the groups were observed only in the frequency of stereo vision formation (p = 0.041). Conclusion. Prismatic correction is a more effective method of functional treatment of patients with congenital esotropia after the surgical stage in comparison with traditional orthoptic treatment, including for children of preverbal age. Keywords: infantile esotropia, single binocular vision, Fresnel prisms.

Conservative management of intermittent exotropia to defer or avoid surgery

Surgery for intermittent exotropia performed at a very young age has poorer sensory outcomes than surgery performed later; moreover, postoperative recurrence is common, regardless of age. Alternate occlusion decreases the size of the exotropia and improves control. The purpose of this study was to report the long-term effects of part-time alternate occlusion and overminus spectacles combined with prism on delaying or avoiding surgery in intermittent exotropia. The study included consecutive patients from 1979 to 2010 who had poorly controlled intermittent exotropia and were treated with alternate occlusion, followed in some cases by overminus spectacles with base-in prism. Outcome measures were initial improvement and subsequent time to surgery, if required. A total of 279 patients had initial control poor enough to otherwise be considered candidates for surgery. After occlusion therapy, 219 (78%) improved their angle and control, and 62 (22%) converted to an exophoria. After 1year, 9 cases deteriorated, and surgery was recommended. In 207 (74%), conservative treatment delayed surgery for at least 1year. At 20years, 42 of 279 patients were still being followed. Of these, 22 of 219 (7%) were known to have not undergone surgery, and 127 (45%) had undergone surgery; 130 (47%) were lost to follow-up. Part-time alternate occlusion and overminus spectacles with prism can defer the need for surgery in a large percentage of patients with intermittent exotropia; for a small number it may be curative.

The effect of alternate occlusion on control of intermittent exotropia in children.

The aim is to investigate the effect of alternate occlusion on control of intermittent exotropia in children 3 to 8 years old. The ability of 28 children to control of the deviation at far and near was evaluated based on 3-point and 6-point control scales. Stereopsis and fusion were assessed using the Titmus and Worth 4-dot tests, respectively. Two-hour alternate daily occlusion was prescribed for children with no dominancy. For children with a dominant eye, 2-h occlusion of the dominant eye for 5 days and the non-dominant eye for 2 days. All measurements were repeated at 3, 6, and 9 months after the treatment. For all children with a mean age of 4.7 ± 1.56 years, deviation control at far improved significantly after 3, 6, and 9 months of treatment using both control scales when compared with baseline (p = 0.005 after 3 months and p = 0.008 after 6 and 9 months for the 3-point scale, and p < 0.001 after 3 and 6 months and p = 0.010 after 9 months for the 6-point scale). Control at near showed a significant improvement after 3, 6, and 9 months of treatment based on the 6-point scale (p = 0.007 for 3 months, p = 0.004 for 6 months, and p = 0.014 for 9 months). Near stereopsis improved significantly after 9 months of treatment (p = 0.043). Alternate occlusion is significantly effective on control of intermittent exotropia. As a result, it can be used as a useful method to postpone or even eliminate the need for surgery in intermittent exotropia.

Heterodonty and double occlusion in Manidens condorensis: a unique adaptation in an Early Jurassic ornithischian improving masticatory efficiency.

New materials of the ornithischian dinosaur Manidens condorensis highlight a strong heterodonty between the upper and lower dentitions and reveal a novel occlusion type previously unreported in herbivorous dinosaurs. The diamond-shaped maxillary teeth have prominent cingular entolophs in a V- to Z-shaped configuration that are absent in dentary teeth. These cingular entolophs bear denticles and serrations with vertical wear that is coplanar with the apical wear facets, supporting their involvement in chewing. The separated apical and basal wear in dentary teeth is consistent with the apical and cingular wear in maxillary teeth, indicating an alternate occlusion, an orthal jaw motion, and shearing interactions between marginal and cingular edges in a double occlusion. Measurements of the length and wear area along the marginal and cingular edges indicate that the latter are functionally equivalent to adding eight teeth to a maxillary toothrow of ten, almost doubling the lengths of cutting edges and the degree of intraoral processing, while maintaining a plesiomorphic skull anatomy, an adaptation to herbivory unique in Ornithischia.

Strabismus Measurements with Novel Video Goggles

To assess the validity of a novel, simplified, noninvasive test for strabismus using video goggles. Cross-sectional method comparison study in which the new test, the strabismus video goggles, is compared with the existing reference standard, the Hess screen test. We studied 41 adult and child patients aged ≥6 years with ocular misalignment owing to congenital or acquired paralytic or comitant strabismus and 17 healthy volunteers. All participants were tested with binocular infrared video goggles with built-in laser target projection and liquid crystal display shutters for alternate occlusion of the eyes and the conventional Hess screen test. In both tests, ocular deviations were measured on a 9-point target grid located at 0±15° horizontal and vertical eccentricity. Horizontal and vertical ocular deviations at 9 different gaze positions of each eye were measured by the strabismus video goggles and the Hess screen test. Agreement was quantified as the intraclass correlation coefficient. Secondary outcomes were the utility of the goggles in patients with visual suppression and in children. There was good agreement between the strabismus video goggles and the Hess screen test in the measurements of horizontal and vertical deviation (intraclass correlation coefficient horizontal 0.83, 95% confidence interval [0.77, 0.88], vertical 0.76, 95% confidence interval [0.68, 0.82]). Both methods reproduced the characteristic strabismus patterns in the 9-point grid. In contrast to Hess screen testing, strabismus video goggle measurements were even possible in patients with comitant strabismus and visual suppression. The new device is simple and is fast and accurate in measuring ocular deviations, and the results are closely correlated with those obtained using the conventional Hess screen test. It can even be used in patients with visual suppression who are not suitable for the Hess screen test. The device can be applied in children as young as 6 years of age.

Does occlusion therapy improve control in intermittent exotropia?

PurposeThe aim of this study was to evaluate the effectiveness of occlusion therapy in the control of intermittent exotropia (IXT) in children between 4 and 10years in Saudi Arabia. This study will highlight the importance of patching IXT patients and assist to approach the proper use of occlusion therapy. MethodsA clinical, prospective cohort pilot study was performed on 21 untreated IXT patients. Evaluation of the deviation angle, amplitudes, stereopsis and control before, during and after occlusion therapy was performed. ResultsEleven percent of the subjects demonstrated a decrease in the deviation angle by 50% while 55.5% attained normal ranges for base-out fusional amplitudes and 77% attained success for the control. ConclusionWe suggest that alternate occlusion therapy can improve the sensory status and strengthen the fusional amplitudes but does not improve the deviation angle and therefore is useful to postpone surgery in young children and may improve surgical outcome.

Endothelial function assessment in nutritional research studies: a comparison of two arterial occlusion sites for assessing reactive hyperemia using a peripheral arterial tonometry device

Endothelial function assessment can be an important tool in evaluating artery health in humans, and can be an important phenotyping tool in nutritional research studies as well as an early indicator of cardiovascular disease. We conducted a study of endothelial function in healthy adults using reactive hyperemia peripheral arterial tonometry (RH‐PAT) by the EndoPAT™ device (Itamar Medical Ltd., Caesarea, Israel) in order to compare two arterial occlusion sites. Brachial artery (upper arm) occlusion is the most common occlusion site, yet a forearm occlusion site may be a potentially valid site for endothelial function testing. RH‐PAT testing is an operator independent, non‐invasive technique that measures the arterial pulse wave amplitude using pneumatic fingertip probes during reactive hyperemia allowing a RH‐PAT index (RHI) to be calculated. Reactive hyperemia was achieved by occluding either the upper arm (brachial artery) or the forearm (ulnar and radial arteries) in the individual using a blood pressure cuff inflated to ~200 mmHg for 5 minutes. Twenty healthy adults (14 female, 6 male), age 38 ± 12 years (mean ± SD) and BMI 24 ± 3 kg/m2 participated in the study. RH‐PAT measurements were determined in the morning after a 12 hour fast. Participants were tested approximately 3 days apart using a crossover design with randomization of upper arm and forearm as occlusion sites. The participant's non‐dominant arm was always the occluded arm. Participants were tested in a quiet, temperature‐controlled (21–24°C) room in a supine position for at least 15 minutes prior to the 15 minute test: 5 minute baseline, 5 minute occlusion, and 5 minute post‐occlusion. A self‐reported numeric pain intensity scale (0–10) was used to evaluate pain during the occlusion and post‐occlusion (hyperemic period) portion of the measurement. The RHI is the post‐to‐pre occlusion PAT signal ratio in the occluded arm, relative to the same ratio in the control arm, corrected for baseline vascular tone of the occluded arm. The mean RHI for the two occlusion sites: 2.15 ± 0.78 (upper arm) and 2.36 ± 0.75 (forearm) was not different (p=0.18, paired t‐test). A Pearson correlation of the RHI from both sites (r=0.602, p=0.005) was positive and significant. The mean reported pain intensity for the upper arm was 3.7 ± 1.3 compared to 2.7 ± 1.8 for the forearm; these indices were significantly different (p=0.002, signed‐rank test). In summary, occlusion of the forearm appears to be a potentially valid alternate occlusion site for RH‐PAT measurement and is less painful than using the upper arm as an occlusion site. In addition, the occlusion site should be standardized in the study protocol. Human study approved by the UC Davis Institutional Review Board.Support or Funding InformationUSDA, ARS Projects: 2032‐51000‐022; 203253000‐001

Alternate occlusion for bilateral ametropic amblyopia

Bilateral ametropic amblyopia occurs in the presence of high refractive error and is attributed to pattern deprivation. Current treatment advocates full-time spectacle wear whilst the use of alternate occlusion and simple occlusion are supported by anecdotal evidence and are implemented as a rare treatment option in some UK hospitals. This study looks at the effectiveness of alternate occlusion and simple occlusion in comparison to spectacles with respect to bilateral ametropic amblyopia.

Results of conservative management for consecutive esotropia after intermittent exotropia surgery.

To examine the clinical course of consecutive esotropia (ET) using conservative management, after intermittent exotropia (IXT) surgery. This study included 149 out of 151 consecutive patients with ET after IXT surgery, who were managed conservatively. The clinical course of consecutive ET was examined and the patients were classified into two groups based on the duration of esodeviation: (1) >3 weeks (persistent ET group, n=56) and (2) <3 weeks (transient ET group, n=93). Patient characteristics and treatment outcomes, including the recurrence of exotropia and stereopsis, were compared between the two groups. All patients with ET were managed with full-time alternate occlusion and/or with a Fresnel prism. In 149 patients out of 151 consecutive patients, 82% of ET disappeared at 12-month follow-up and all at the last follow-up visit (31.4±23.5 months). At the final visit, a recurrence of exotropia of >10 prism dioptres was significantly less frequent in the persistent ET group than in the transient ET group (25% vs 62%, respectively; P=0.01). However, stereopsis outcome was not significantly different between the two groups, and stereopsis change was not affected by age. By using conservative management only, persistent consecutive ET after IXT surgery disappeared in most cases by the 1-year follow-up visit after surgery. Recurrence of exotropia was significantly less frequent in patients with persistent ET, yet the sensory outcome was not affected by the duration of consecutive ET or age.

Relative roles of luminance and fixation in inducing dissociated vertical divergence.

We evaluated the roles of luminance and fixation in the pathophysiology of dissociated vertical divergence (DVD). Vertical eye position was measured in 6 subjects with DVD (ages 11-47 years, 5 females) and 6 controls (ages 16-40 years, 5 females) using video-oculography (VOG) under conditions of change in fixation and luminance. Subjects with DVD showed the following VOG responses. When fixation was precluded with a translucent filter and bright light was shone into one eye to produce a marked binocular luminance disparity, we found some subjects had a small induced vertical divergence causing the illuminated eye to be lower than the nonilluminated eye (mean -1.6° ± 1.5°, P = 0.06 compared to no vertical divergence using the signed rank test). When fixation was precluded with a translucent filter, while alternate occlusion produced a mild binocular luminance disparity, we found a smaller vertical divergence of the eyes that was not statistically significant (1.2° ± 2.1°, P = 0.3). When alternate occlusion produced reversal of monocular fixation in the dark (with essentially no change in peripheral luminance disparity), there was a significant vertical divergence movement causing the covered eye to be relatively higher than the uncovered eye (7.2° ± 3.1°, P = 0.03). The amplitude of this vertical divergence was similar to that measured under conditions of alternate occlusion in a lighted room (where there also was a significant average relative upward movement of the covered eye of 8.1° ± 2.9°, P = 0.03). Control subjects showed no vertical divergence under any testing conditions. Dissociated vertical divergence is mediated primarily by changes in fixation and only to a minor degree by binocular luminance disparity.

Comparison of four different binocular balancing techniques

BackgroundSeveral techniques of balancing have been proposed for the equalisation of the accommodative state between the two eyes. This study was designed to compare the results of different balancing techniques.MethodsIn this study, 60 subjects participated. Refractive errors were determined using retinoscopy and results were refined with monocular subjective refraction to determine the ametropia with the most plus lens and this was used as the starting point for balancing. The monocular refractive values before the balance were the same for all balancing procedures. Four balancing techniques, three dissociated and one associated, (alternate occlusion, prism‐dissociated blur balance, prism‐dissociated red‐green balance and Humphriss immediate contrast method) were used for the final refinement of findings. Results were analysed as the interocular spherical difference (IOSD) after the completion of each balance procedure. The interocular spherical difference was defined as the right eye sphere minus the left eye sphere. Data were analysed in SPSS.17 software using the paired samples t‐test, the Pearson correlation, repeated measures ANOVA and ‘intraclass correlation coefficient’ (ICC) tests.ResultsThe lowest mean difference was related to the alternate occlusion with the prism‐dissociated blur balance techniques. The lowest 95% limits of agreement were related to the prism‐dissociated red‐green balance with the Humphriss immediate contrast methods. The highest correlation and intraclass correlation coefficient were related to the prism‐dissociated red‐green balance with the Humphriss immediate contrast methods.ConclusionsThe four balancing methods yield very similar results. The balance findings with red‐green dissociated method and the Humphriss immediate contrast technique can be considered interchangeable and the other pairs of comparisons very nearly so.

Successful alignment following multiple surgeries in a child with severe esotropia and a congenital cranial dysinnervation disorder

Aim: To report the alignment, visual outcome and surgical strategy for severe bilateral congenital esotropia caused by a congenital cranial dysinnervation disorder (CCDD). This was successfully treated with a combination of interventions that included alternate occlusion, botulinum toxin, and conventional and augmented transposition procedures. Methods: A girl presented at 2 months of age with a marked esotropia and severe bilateral impairment of abduction of both eyes, and an inability to fix with either eye in the primary position. Her investigation and treatment are described. Results: The patient initially underwent alternate daily occlusion to prevent the development of amblyopia, followed by simultaneous bilateral medial rectus (MR) botulinum toxin and large bilateral MR recessions based on pre-operative forced duction testing (FDT). This operation was performed at 1 year of age with the aim of releasing the tight MR and reducing the esotropia. After initial improvement, the impairment of abduction gradually increased over the next month. She subsequently underwent sequential inferior oblique myectomy and augmented transposition procedures, which enabled her to fix in the primary position with either eye and with a small-angle esotropia. Conclusion: Substantial improvement in the alignment of the eyes in a child with a complex congenital esotropia secondary to a CCDD is achievable.

Remote treatment of intermittent central suppression improves quality-of-life measures

Background Intermittent central suppression (ICS) is a repetitive intermittent (“on-and-off”) loss of central visual sensation without strabismus or amblyopia. These repetitive seconds-long suppressions have been suggested to create visual confusion and instability that would cause vision symptoms, contribute to reading complaints, and even impair reading. Methods Teacher-identified Job Corps students were diagnosed with ICS and then treated with 5-Hz electronic liquid crystal shutter alternate occlusion. Results Twenty-six young adult students (19.7 ± 1.6 y) had their ICS treated over 5.9 ± 3.7 months. Suppression periods decreased in length ( P < 0.0001) and “binocular” nonsuppressed periods increased in length ( P < 0.0001). Overall, College of Optometrists in Vision Development (COVD) quality-of-life (QOL) scores improved ( P < 0.0001), 16 reading behavior COVD QOL questions improved ( P < 0.0001), and individual QOL questions improved. Posttherapy reading scores (N = 18) improved 3.7 (± 2.6) years ( P < 0.0001). Conclusions Treating ICS with electronic alternate occlusion reduced suppression periods, increased binocular periods, and improved symptoms as measured in the COVD QOL questionnaire. Positive changes also occurred in reading scores. These data suggest ICS should be considered a probable cause for symptoms of reading problems.

Clinical Course of Patients with Consecutive Esotropia Angle Larger Than Preoperative Angle After Exotropia Surgery

Purpose: To report the clinical course of severe consecutive esotropia (ET) with an esotropic angle at postoperative day 1 larger than the preoperative exotropia angle (XT). Methods: Patients with ET angles at postoperative 1 day greater than their preoperative XT angles were included; the case of lost lateral rectus during surgery was excluded. Preoperative clinical characteristics and the course of postoperative alignment were analyzed, and binocularity was compared between the preoperative state and the postoperative state. Results: The mean preoperative angle of XT of 13 patients was 23 prism diopters (PD) at distance and 27PD at near. Lateral incomitancy was observed in 9 patients. One day postoperatively, the mean angle of ET was 27PD at distance and 25PD at near, and alternate occlusion therapy was performed in all patients. However, the angle of ET was decreased 10PD or less in only 3 patients. All 13 patients were managed with Fresnel prisms, and 4 patients had orthotropia. Another 4 patients used glass prisms because they had ET of 8PD or less, and the remaining 5 patients still showed an ET with 12PD or more. Binocularity after surgery was worse than that before surgery in 64% of patients. Conclusions: For patients with ET angles at postoperative 1 day greater than preoperative XT angles, the frequency of lateral incomitancy was high. Alternate occlusion and Fresnel prism treatment were needed in all patients. Recovery from orthotropia and the prognosis of binocularity were relatively poor.

The clinical course of consecutive esotropia after surgical correction.

PurposeTo investigate the clinical course in patients who underwent surgical correction of consecutive esotropia.MethodsThe medical records of 13 patients who underwent surgical correction of consecutive esotropia were reviewed retrospectively. The authors investigated the deviation and surgical method at the time of exotropia surgery. During the follow up period, the authors also studied incidence of amblyopia development, the effect of occlusion therapy, surgical methods for consecutive esotropia, and postoperative change of deviation.ResultsThe average exodeviation was 27.1 prism diopter (PD). Bilateral lateral rectus muscle recession was performed in all patients. In all patients, alternate occlusion was tried from 2 weeks after development of consecutive esotropia. However, there was no effect on 7 patients. None of the patients developed amblyopia. Surgery for consecutive esotropia was performed on the average 15.3 months after exotropia surgery. The average esodeviation was 21.1PD. Medial rectus muscle recession was performed in 10 patients and lateral rectus muscle advancement in 3 patients. The average deviation of the subject group immediately after surgery was 1.2PD esodeviation, 0.9PD esodeviation one month after surgery, 2.4PD exodeviation 6 months after surgery, and 4.7PD exodeviation at the last follow up, and it showed a tendency to progress to exodeviation as the follow up period increased. Ten patients (76.9%) showed deviation within 8PD at the last follow up.ConclusionsThe success rate of surgical correction for consecutive esotropia was a favorable outcome. But, careful decisions of the surgical method and amount is needed because the conversion of exodeviation during long-term follow-up is possible.

Placement of an Arterial Line

Indications Radial arterial lines are important tools in the treatment of critically ill patients. Continuous monitoring of blood pressure is indicated for patients with hemodynamic instability that requires inotropic or vasopressor medication. An arterial line allows for consistent and continuous monitoring of blood pressure to facilitate the reliable titration of supportive medications. In addition, arterial lines allow for reliable access to the arterial circulation for the measurement of arterial oxygenation and for frequent blood sampling. The placement of arterial lines is an important skill for physicians to master as they treat critically ill patients. An arterial line is also indicated for patients with significant ventilatory deficits. Measurement of the partial pressures of arterial oxygen and arterial carbon dioxide provides more information about the status of gas exchange than does arterial oxygen saturation. Contraindications The contraindications to the placement of an arterial line are few but specific. Placement of an arterial line should not compromise the circulation distal to the placement site, which means that sites with known deficiencies in collateral circulation — such as those involved in Raynaud’s phenomenon and thromboangiitis obliterans or end arteries such as the brachial artery — should be avoided. The value of the Allen test, which is used to verify collateral circulation to the hand through alternate occlusion of the radial and ulnar arteries while the hand is checked for perfusion, is somewhat controversial. Some studies have been able to demonstrate adequate perfusion with the use of other techniques that contradict the results of the Allen test. 1,2 Other contraindications include infection of the site where the catheter is to be placed and traumatic injury proximal to the proposed insertion site. Preparation There are several techniques for the placement of a radial arterial line; two of the more common are known as “over the wire” and “over the needle.” A modified Seldinger technique can also be used but is not described in this video. Preparation for both techniques is identical. The equipment needed includes a sterile preparation solution and a sterile field, a board and tape to secure and position the wrist, 1 percent lidocaine solution (without epinephrine) and a smallgauge needle and syringe for delivery, an angiographic catheter and needle, a wire if the over-the-wire technique is to be used, material such as suture or tape to secure the line once it has been placed, and a transduction system for monitoring. After the risks of the procedure have been appropriately assessed and consent has been obtained from the patient, the hand should be positioned on the wrist board. The hand should be placed in moderate dorsiflexion, which brings the artery videos in clinical medicine

A Prospective Study of Alternating Occlusion Before Surgical Alignment for Infantile Esotropia: One-Year Postoperative Motor Results

Alternating occlusion before surgical alignment has been suggested by some strabismologists as a possible method to enhance the treatment of infantile esotropia. This report presents 1-year outcome results of a prospective trial of patients with infantile esotropia who were assigned randomly to alternating occlusion or control groups. Forty-four patients with infantile esotropia were measured at entry into the study, at the time of surgery, at 6 weeks, and 1 year postoperatively. Alternating occlusion was full time and symmetric for those with no amblyopia but asymmetric for those with amblyopia. The control group that did not receive alternating occlusion had occlusion for amblyopia only. Initial surgeries were performed when the patients were between the ages of 6 and 13 months. Overall, the patients showed an increase of 9.14 prism diopters (PD) during a mean preoperative follow-up of 4.2 months. Seventy-five percent of all patients were aligned by the initial surgery. Ninety-one percent of those patients aligned within 10 PD at 6 weeks also were aligned 1 year postoperatively. The results were similar for the alternate occlusion group and the control group. In our sample of patients, alternating occlusion does not detectably alter the increase in angle of deviation between the dates of entry and the date of the initial surgical alignment procedure, nor does it influence the postoperative alignment at 6 weeks or at 1 year.

INVITED COMMENTARY

Coronary artery bypass grafting (CABG) with saphenous vein conduits is one of the most commonly performed surgical procedures worldwide. Unfortunately, saphenous vein graft patency is only 50% at 10 years. As a result, there has been a growing interest in the use of arterial conduits, particularly the radial artery (RA), as excellent midterm patency results of more than 90% have been reported. Nevertheless, concerns have been raised about decreased blood flow to the hand with potential morbidity after RA harvesting. This paper by Knobloch and colleagues describes a novel combined laser-Doppler flowmeter system that can be used to measure palmar microcirculation in attempts to avoid ischemic complications of the hand. Palmar circulation was evaluated using the laser-Doppler flowmeter before and 2 days after RA harvesting. Patients were tested for either complete suprasystolic occlusion of the brachial artery or alternate occlusion of the radial and ulnar arteries. As expected, changes in both blood flow and tissue oxygenation saturation decreased with various occlusive maneuvers. After RA harvest, tissue flows and saturations were the same as for the nondonor hand. This “proof-of-concept” study is small with only 15 patients, all of whom were less than 60 years of age. One wonders how well this system would work in the elderly, smoking, or diabetic population with small vessel occlusive disease. By including more patients and then applying a subgroup analysis, the authors might have answered this question. The Allen test is simple and safe, and is performed commonly to assess palmar circulation. Unfortunately, the authors make no mention of whether concomitant Allen testing was performed in any of these patients. Furthermore, there are no comparative results or descriptions of how the device might be more reliable than the Allen test. Correlation with the laser-Doppler flowmeter system would have been interesting and would have validated the utility. Nevertheless, one of the more interesting points of the paper was that despite reduction in palmar blood flow and tissue oxygen saturation with RA harvesting, 2 days postoperatively both tissue oxygen saturation and blood flow were not reduced compared with the other hand and, more importantly, compared with preoperative values. Potential mechanisms might include increased compensatory blood flow from the remaining artery or the opening of small collaterals within the palmar arch hand. This finding raises a critical point in the use of this new technology. Should decreases in blood flow and tissue oxygen saturation be disregarded as they return to baseline 2 days after RA harvest, or is there some dangerous threshold before RA harvesting that can be detected by this new method? In summary, further work will need to include a wider patient population to determine whether this technology can add more clinical information for patients whose RA is harvested. Moreover, will this device predict and detect who may have postoperative ischemic complications? This important question must be answered before surgeons can conclude that the laser-Doppler flowmeter will add functional information that goes beyond the Allen test.

Masticatory morphological diversity and chewing modes in South American caviomorph rodents (family Octodontidae)

AbstractThe relationship between masticatory morphology and chewing modes in all living genera of South American rodents in the family Octodontidae was analysed. Chewing directions and the patterns of molar occlusion were assessed. Factor and regression analyses of skull and jaw characters, and attributes of the adductor musculature, especially the line of action of masseters and pterygoids, were performed to check their relations with the chewing modes. Two basic chewing strategies are present in octodontids: oblique unilateral (associated with anterolingual jaw displacement, and alternate occlusion of left and right molar series), and propalinal bilateral (associated with mostly posteroanterior jaw displacement, and simultaneous occlusion). The skull and jaw characters examined are related only partly to these chewing strategies. The temporal pattern of muscle contraction provides a possible explanation for such a functional versatility. Propalinal grinding in octodontids could be achieved through simultaneous muscle contraction, with limited reliance on the lines of action of the involved muscles. Therefore, simultaneous contraction explains a similar propalinal masticatory mode in morphologically disparate genera. In accordance with phylogenetic information, oblique unilateral chewing is primitive in octodontids, and the derived propalinal mode has been developed independently at least twice in the evolution of the family.

New remains of Sphagesaurus huenei (Crocodylomorpha: Mesoeucrocodylia) from the Late Cretaceous of Brazil

ABSTRACT Recent discovery of an almost complete skull of Sphagesaurus huenei, a previously poorly known form from the Late Cretaceous of southern Brazil, shows unexpected morphology for a crocodyliform, including an extreme heterodonty with small lower incisors, large upper caniniforms, and reversed triangle-like postcanines; edentulous anterior region of premaxilla; and maxilla with posterior wall over the anterior margin of the suborbital fenestra. The postcanine teeth have extensive wear facets, implying an alternate unilateral occlusion and suggesting the presence of both lateral and fore-aft movement of the jaw. These characteristics appear unique within the crocodyliform lineage, showing that feeding diversity was wider than thought in this clade. The phylogenetic relationships of Sphagesaurus huenei are evaluated through a parsimony analysis. Sphagesaurus lies within a monophyletic group formed by Cretaceous and Tertiary taxa traditionally referred as notosuchians and sebecosuchians. Interestingly, several mammal-like tooth morphologies were present in this clade of terrestrial crocodyliforms.