The Effect of Regional Anaesthesia on Free Flap Survival in Lower Extremity Reconstructions.

Background: The effect of different modalities of anaesthesia in microvascular free flap surgery has been a topic of ongoing debate. Comparative data to study the effect of general anaesthesia and regional anaesthesia in the form of peripheral nerve blocks (PNBs) on lower extremity free flap survival is lacking to date. This study aims to elucidate the effect of regional anaesthesia on flap survival in lower extremity free flap reconstructions. Methods: A retrospective cohort study of all patients who underwent free vascularised flap reconstruction of the lower extremities between 2012 and 2021 at the Amsterdam University Medical Centre (UMC), The Netherlands, and between 2019 and 2021 at the Radboud UMC, Nijmegen, The Netherlands. In this cohort, we analysed partial and total flap failures. Results: In this cohort, 87 patients received a total of 102 microvascular free flap reconstructions of the lower extremity. In 20.5% of these operations, patients received a supplemental PNB. Total flap failure was 23.8% in the regional anaesthesia group compared to 21% in the group with general anaesthesia only (p = 0.779). Operation time was longer for patients with regional anaesthesia (p = 0.057). Length of stay was on average 2 days shorter for patients with supplemental regional anaesthesia (p = 0.716). Discussion: This is the largest cohort comparing flap survival in patients receiving general anaesthesia to general anaesthesia with a PNB in lower extremity reconstructions to date. We cannot attribute a significant beneficial or detrimental effect of regional anaesthesia to flap survival. High failure rates stress the need for future studies. How to cite this article: Koster ITS, den Os MM, Rutten MVH, et al. The Effect of Regional Anaesthesia on Free Flap Survival in Lower Extremity Reconstructions. Strategies Trauma Limb Reconstr 2024;19(1):15-20.

Patient-reported esthetic outcomes following lower extremity free flap reconstruction: A cross-sectional multicenter study.

INTRODUCTION: The goal of lower-extremity reconstructions is primarily to salvage the leg; however, esthetic outcomes are also important. This study aimed to assess the impact of a lower extremity free tissue transfer regarding social functioning, patient-reported esthetic outcomes, and possible differences between fasciocutaneous vs. muscle flaps. MATERIAL AND METHODS: For this cross-sectional multicenter study, patients operated between 2003 and 2021, with a minimum follow-up of 12 months, were identified. Outcomes were obtained from 89 patients. Patient-reported outcomes were assessed using a questionnaire containing 5-point Likert scale questions grouped in three groups: aspect of the reconstructed leg, the aspect of the donor site, and the negative impact on social functioning. Physical functioning and mental health were assessed with the Short-Form-36. RESULTS: The overall score for negative impact on social functioning was 22.2. This was 46.7 for the esthetic satisfaction of the reconstructed leg and 57.1 for the donor site. No significant differences were seen between patients who underwent a reconstruction with a fasciocutaneous flap compared to a muscle flap. Secondary surgical procedures for improving the esthetic aspect were performed in 12% of the patients in the fasciocutaneous group and 0% in the muscle group. CONCLUSION: Our results show that the most optimal esthetic outcome is not defined by the type of flap. We found a strong correlation between physical functioning and the negative impact on social functioning that a reconstructed lower extremity may have. The result of this study can be taken into consideration during the shared decision-making process of choosing the most optimal reconstruction.

Mental health is strongly associated with capability after lower extremity injury treated with free flap limb salvage or amputation.

BACKGROUND: Knowledge about factors associated with long-term outcomes, after severe traumatic injury to the lower extremity, can aid with the difficult decision whether to salvage or amputate the leg and improve outcome. We therefore studied factors independently associated with capability at a minimum of 1 year after amputation or free flap limb salvage. METHODS: We included 135 subjects with a free flap lower extremity reconstruction and 41 subjects with amputation, between 1991 and 2021 at two urban-level 1 trauma centers with a mean follow-up of 11 ± 7 years. Long-term physical functioning was assessed using the Physical Component Score (PCS) of the Short-Form 36 (SF36) and the Lower Extremity Functional Scale (LEFS) questionnaires. Independent variables included demographics, injury characteristics, and the Mental Component Score (MCS) of the SF36. RESULTS: Greater mental health was independently and strongly associated with greater capability, independent of amputation or limb reconstruction. Mental health explained 33% of the variation in PCS and 57% of the variation in LEFS. Injury location at the knee or leg was associated with greater capability, compared to the foot or ankle. Amputation or limb reconstruction was not associated with capability. DISCUSSION: This study adds to the growing body of knowledge that physical health is best regarded through the lens of the bio-psycho-social model in which mental health is a strong determinant. This study supports making mental health an important aspect of rehabilitation after major lower extremity injury, regardless of amputation or limb salvage.

The effectiveness of acellular nerve allografts compared to autografts in animal models: A systematic review and meta-analysis.

BACKGROUND: Treatment of nerve injuries proves to be a worldwide clinical challenge. Acellular nerve allografts are suggested to be a promising alternative for bridging a nerve gap to the current gold standard, an autologous nerve graft. OBJECTIVE: To systematically review the efficacy of the acellular nerve allograft, its difference from the gold standard (the nerve autograft) and to discuss its possible indications. MATERIAL AND METHODS: PubMed, Embase and Web of Science were systematically searched until the 4th of January 2022. Original peer reviewed paper that presented 1) distinctive data; 2) a clear comparison between not immunologically processed acellular allografts and autologous nerve transfers; 3) was performed in laboratory animals of all species and sex. Meta analyses and subgroup analyses (for graft length and species) were conducted for muscle weight, sciatic function index, ankle angle, nerve conduction velocity, axon count diameter, tetanic contraction and amplitude using a Random effects model. Subgroup analyses were conducted on graft length and species. RESULTS: Fifty articles were included in this review and all were included in the meta-analyses. An acellular allograft resulted in a significantly lower muscle weight, sciatic function index, ankle angle, nerve conduction velocity, axon count and smaller diameter, tetanic contraction compared to an autologous nerve graft. No difference was found in amplitude between acellular allografts and autologous nerve transfers. Post hoc subgroup analyses of graft length showed a significant reduced muscle weight in long grafts versus small and medium length grafts. All included studies showed a large variance in methodological design. CONCLUSION: Our review shows that the included studies, investigating the use of acellular allografts, showed a large variance in methodological design and are as a consequence difficult to compare. Nevertheless, our results indicate that treating a nerve gap with an allograft results in an inferior nerve recovery compared to an autograft in seven out of eight outcomes assessed in experimental animals. In addition, based on our preliminary post hoc subgroup analyses we suggest that when an allograft is being used an allograft in short and medium (0-1cm, > 1-2cm) nerve gaps is preferred over an allograft in long (> 2cm) nerve gaps.

Radial Icicle Tree (RIT): Node Separation and Area Constancy.

Icicles and sunbursts are two commonly-used visual representations of trees. While icicle trees can map data values faithfully to rectangles of different sizes, often some rectangles are too narrow to be noticed easily. When an icicle tree is transformed into a sunburst tree, the width of each rectangle becomes the length of an annular sector that is usually longer than the original width. While sunburst trees alleviate the problem of narrow rectangles in icicle trees, it no longer maintains the consistency of size encoding. At different tree depths, nodes of the same data values are displayed in annular sections of different sizes in a sunburst tree, though they are represented by rectangles of the same size in an icicle tree. Furthermore, two nodes from different subtrees could sometimes appear as a single node in both icicle trees and sunburst trees. In this paper, we propose a new visual representation, referred to as radial icicle tree (RIT), which transforms the rectangular bounding box of an icicle tree into a circle, circular sector, or annular sector while introducing gaps between nodes and maintaining area constancy for nodes of the same size. We applied the new visual design to several datasets. Both the analytical design process and user-centered evaluation have confirmed that this new design has improved the design of icicles and sunburst trees without introducing any relative demerit.

Motor and sensory nerve transfers in the lower extremity: Systematic review of current reconstructive possibilities.

BACKGROUND: Peripheral nerve injuries (PNI) are predominantly treated by anatomical repair or reconstruction with autologous nerve grafts or allografts. Motor nerve transfers for PNI in the upper extremity are well established; however, this technique is not yet widely used in the lower extremity. This literature review presents an overview of the current options and postoperative results for nerve transfers as a treatment for nerve injury in the lower extremity. METHODS: A systematic search in PubMed and Embase databases was performed. Full-text English articles describing surgical procedures and postoperative outcomes of nerve transfers in the lower extremity were included. The primary outcome was postoperative muscle strength measured using the British Medical Research Council (MRC) scale, with MRC> 3 considered good and postoperative return of sensation reported according to the modified Highet classification. RESULTS: A total of 36 articles for motor nerve transfer and 7 for sensory nerve transfer were included. Sixteen articles described motor nerve transfers for treating peroneal nerve injury, 17 for femoral nerve injury, 2 for tibial nerve injury, and one for obturator nerve injury. Transfers of multiple branches to restore deep peroneal nerve function led to a good outcome in 58% of patients and 43% when a single branch was used as a donor. The transfer of multiple branches for femoral nerve or obturator nerve repair was performed in all reported patients with a good outcome. CONCLUSIONS: The transfer of motor nerves for the recovery of PNI is a feasible technique with relatively low risks and great benefits. The correct indication, timing, and surgical technique are essential for optimizing results.

Strategies Following Free Flap Failure in Lower Extremity Trauma: A Systematic Review.

Background: Free flap reconstructions are an important reconstructive option for soft tissue defects in mangled lower extremities. Microsurgery facilitates soft tissue coverage of defects that otherwise would result in amputation. However, the success rates of traumatic lower extremity free flap reconstructions remain lower than those in other locations. Nevertheless, post-free flap failure salvage strategies have rarely been addressed. Therefore, the current review aims to provide an overview of post-free flap failure strategies in lower extremity trauma and their subsequent outcomes. Methods: A search of Pubmed, Cochrane, and Embase databases was performed on June 9, June 2021 using the following medical subject headings (MeSH) search terms: 'lower extremity', 'leg injuries', 'reconstructive surgical procedures', 'reoperation', 'microsurgery' and 'treatment failure'. This review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Partial and total free flap failures after traumatic reconstruction were included. Results: Twenty-eight studies with a total of 102 free flap failures fulfilled the eligibility criteria. Following the total failure, a second free flap is the predominant reconstructive strategy (69%). In comparison to the failure rate of a first free flap (10%), the fate of a second free flap is less favorable with a failure rate of 17%. The amputation rate following flap failure is 12%. The risk of amputation increases between primary and secondary free flap failures. After partial flap loss, the preferred strategy is a split skin graft (50%). Conclusion: To our knowledge, this is the first systematic review on the outcome of salvage strategies after free flap failure in traumatic lower extremity reconstruction. This review provides valuable evidence to take into consideration in the decision-making regarding post-free flap failure strategies.

A systematic review and meta-analysis on the use of fibrin glue in peripheral nerve repair: Can we just glue it?

BACKGROUND: Within the field of peripheral nerve surgery, the use of fibrin glue as an alternative to conventional microsurgical suture repair is becoming increasingly popular. Advantages of fibrin glue for nerve reconstruction include technical ease of use, less tissue manipulation, and shorter operation times. Although fibrin glue seems a promising alternative to conventional microsurgical repair, further insight into the outcomes of nerve recovery is essential. OBJECTIVE: To summarize the current literature on the use of fibrin glue for peripheral nerve repair and compare these results with outcomes following conventional suture repair. METHODS: A systematic search in Embase, MEDLINE, Web of Science, Cochrane, and Google Scholar databases was performed. The search included animal, cadaveric, and human studies assessing outcomes following peripheral nerve repair using fibrin glue. Data on outcomes were subdivided into functional outcomes, electrophysiology, histopathology, biomechanical outcomes, and operation times. We calculated standardized mean differences and combined these in a random effects model to estimate the overall effect. RESULTS: From a total of 2057 references, 37 animal, two cadaveric, and four human studies were included. Fibrin glue repairs resulted in similar functional and electrophysiology outcomes and shorter operation times than suture repairs. However, fibrin glue alone resulted in lower strength and more dehiscence. No dehiscence was reported when fibrin glue was combined with one or two sutures. Yet, we also found that methodological details were poorly reported in animal studies, resulting in an unclear risk of bias. This should be taken into consideration when interpreting the results. CONCLUSION: The results indicate that nerve regeneration may be similar in fibrin glue repairs and suture repairs. Combining fibrin glue with one or two positional sutures allows for a precise realignment of the nerve fibers and seems to provide sufficient strength to prevent dehiscence.

Nerve recovery from treatment with a vascularized nerve graft compared to an autologous non-vascularized nerve graft in animal models: A systematic review and meta-analysis.

BACKGROUND: Treatment of nerve injuries proves to be a worldwide clinical challenge. Vascularized nerve grafts are suggested to be a promising alternative for bridging a nerve gap to the current gold standard, an autologous non-vascularized nerve graft. However, there is no adequate clinical evidence for the beneficial effect of vascularized nerve grafts and they are still disputed in clinical practice. OBJECTIVE: To systematically review whether vascularized nerve grafts give a superior nerve recovery compared to non-vascularized nerve autografts regarding histological and electrophysiological outcomes in animal models. MATERIAL AND METHODS: PubMed and Embase were systematically searched. The inclusion criteria were as follows: 1) the study was an original full paper which presented unique data; 2) a clear comparison between a vascularized and a non-vascularized autologous nerve transfer was made; 3) the population study were animals of all genders and ages. A standardized mean difference and 95% confidence intervals for each comparison was calculated to estimate the overall effect. Subgroup analyses were conducted on graft length, species and time frames. RESULTS: Fourteen articles were included in this review and all were included in the meta-analyses. A vascularized nerve graft resulted in a significantly larger diameter, higher nerve conduction velocity and axonal count compared to an autologous non-vascularized nerve graft. However, during sensitivity analysis the effect on axonal count disappeared. No significant difference was observed in muscle weight. CONCLUSION: Treating a nerve gap with a vascularized graft results in superior nerve recovery compared to non-vascularized nerve autografts in terms of axon count, diameter and nerve conduction velocity. No difference in muscle weight was seen. However, this conclusion needs to be taken with some caution due to the inherent limitations of this meta-analysis. We recommend future studies to be performed under conditions more closely resembling human circumstances and to use long nerve defects.

A tutorial on Bayesian multi-model linear regression with BAS and JASP.

Linear regression analyses commonly involve two consecutive stages of statistical inquiry. In the first stage, a single 'best' model is defined by a specific selection of relevant predictors; in the second stage, the regression coefficients of the winning model are used for prediction and for inference concerning the importance of the predictors. However, such second-stage inference ignores the model uncertainty from the first stage, resulting in overconfident parameter estimates that generalize poorly. These drawbacks can be overcome by model averaging, a technique that retains all models for inference, weighting each model's contribution by its posterior probability. Although conceptually straightforward, model averaging is rarely used in applied research, possibly due to the lack of easily accessible software. To bridge the gap between theory and practice, we provide a tutorial on linear regression using Bayesian model averaging in JASP, based on the BAS package in R. Firstly, we provide theoretical background on linear regression, Bayesian inference, and Bayesian model averaging. Secondly, we demonstrate the method on an example data set from the World Happiness Report. Lastly, we discuss limitations of model averaging and directions for dealing with violations of model assumptions.

Long-Term Quality of Life after Free Flap Upper Extremity Reconstruction for Traumatic Injuries.

BACKGROUND: Microsurgical reconstruction of upper extremity injuries is often challenging, and the resulting impact on the quality of life (QoL) may be significant. However, there is a lack of knowledge on long-term patient-reported QoL. METHODS: In a retrospective long-term follow-up study, all consecutive patients with an upper extremity injury who had undergone a free flap reconstruction were identified and categorized into three groups based on the type of injury. Patient-reported upper extremity function and QoL were assessed using three validated questionnaires: the 36-item Short Form Health Survey (SF-36), the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, and the Michigan Hand Outcomes Questionnaire (MHQ). RESULTS: A total of 61 patients were identified, of whom 10% had undergone a free flap reconstruction for soft tissue loss only, 62% for an injury accompanied by a fracture, and 28% for a (sub) total amputation. Twenty-one (44%) patients responded to the questionnaires, with a mean follow-up time of 9.7 ± 6.2 years. Patients, on average, reported poorer SF-36 "physical component score" and "role limitations due to physical health" scores compared with Dutch norms. Also, they reported poorer mean DASH scores compared with the general population, indicating worse upper extremity function. Mean MQH scores were lower for the injured side compared with the noninjured side. Pain correlated negatively with the total scores of DASH, MHQ, and SF-36. CONCLUSION: Free flap upper extremity reconstruction is challenging. At 10 years of follow-up, the injury and its treatment continued to have a significant impact on the upper extremity function and daily QoL, with chronic pain being an important factor negatively affecting these outcomes.

Long-Term Outcomes after Double Free Flap Reconstruction for Locally Advanced Head and Neck Cancer.

BACKGROUND: The use of simultaneous, multiple free flaps has become a reliable reconstructive option in patients with extensive composite defects after resection of locally advanced head and neck cancer. However, some reluctance remains among reconstructive surgeons with concerns regarding flap outcomes and limited patient survival. Therefore, we evaluated complications, long-term patient survival, and patient-reported outcomes following these extensive head and neck reconstructions. METHODS: All consecutive patients treated with multiple free flaps for reconstruction of extensive composite defects after resection of locally advanced head and neck cancer between 1999 and 2014 were retrospectively reviewed. Patient charts were evaluated for demographics, treatment details, complications, and patient survival. In addition, all patients alive at the start of the study were asked to complete the 10-item Eat Assessment Tool (EAT-10) and the Intelligibility Rating Scale (IRS). RESULTS: Eighty-four simultaneous, multiple free flaps were performed in 42 patients. The predominant free flap combination consisted of a fibula with either an anterolateral thigh (n = 22) or a radial forearm flap (n = 14). Complete flap survival was 95%. Nineteen patients were still alive with a mean follow-up of 55 months. Five-year patient survival was 46.3%. Mean EAT-10 score was 8.4 (range: 0-29), with only one patient reporting problematic swallowing. Ninety percent of the patients had moderate to good speech intelligibility with the IRS. CONCLUSION: Multiple, simultaneous free flaps can be performed safely, leading to acceptable long-term patient survival and patient-reported functional outcomes. Our study demonstrates that it is worthwhile to perform these challenging microvascular reconstructions in patients with locally advanced head and neck cancer.

Long-Term Patient-Reported Outcomes following Free Flap Lower Extremity Reconstruction for Traumatic Injuries.

BACKGROUND: Reconstruction of severe lower extremity injuries using free flaps has become a reliable approach. Knowledge of long-term surgical outcomes, limb function, and quality of life is limited. METHODS: Two hundred thirty-nine patients undergoing a free flap reconstruction of an open lower extremity fracture between 1993 and 2014 were divided into three groups and studied, as follows: group 1, early free flap reconstruction within 6 weeks; group 2, delayed reconstruction after 6 weeks; and group 3, delayed reconstruction with osteomyelitis. Patient-reported outcomes were assessed with the 36-Item Short-Form Health Survey and the Lower Extremity Functional Scale. Independent variables predicting outcomes were identified using multivariate analyses. RESULTS: Patients in group 3 significantly more often experienced delayed union. Questionnaires were completed by 108 patients (mean follow-up, 9.7 years). The 36-Item Short-Form Health Survey physical component scores were significantly lower in all three groups compared with Dutch norms, as was the mental health score in group 3. There were no significant differences in quality of life and lower limb function among the three groups. Chronic pain was an independent predictor for decreased quality of life and limb function in groups 1 and 2, as was delayed union for decreased limb function in group 3. CONCLUSIONS: After free flap reconstruction of severe lower extremity injuries, all patient groups showed significantly lower quality of life compared to the Dutch population; however, there were no significant differences between the groups. Predictors for poorer quality of life and limb function were chronic pain and delayed union.

Bayesian inference for psychology. Part II: Example applications with JASP.

Bayesian hypothesis testing presents an attractive alternative to p value hypothesis testing. Part I of this series outlined several advantages of Bayesian hypothesis testing, including the ability to quantify evidence and the ability to monitor and update this evidence as data come in, without the need to know the intention with which the data were collected. Despite these and other practical advantages, Bayesian hypothesis tests are still reported relatively rarely. An important impediment to the widespread adoption of Bayesian tests is arguably the lack of user-friendly software for the run-of-the-mill statistical problems that confront psychologists for the analysis of almost every experiment: the t-test, ANOVA, correlation, regression, and contingency tables. In Part II of this series we introduce JASP ( http://www.jasp-stats.org ), an open-source, cross-platform, user-friendly graphical software package that allows users to carry out Bayesian hypothesis tests for standard statistical problems. JASP is based in part on the Bayesian analyses implemented in Morey and Rouder's BayesFactor package for R. Armed with JASP, the practical advantages of Bayesian hypothesis testing are only a mouse click away.

Posterior corneal shape: Comparison of height data from 3 corneal topographers.

PURPOSE: To compare the ability of 3 clinical corneal topographers to describe the posterior corneal shape. SETTING: University Medical Center Groningen, the Netherlands. DESIGN: Prospective observational study. METHODS: Corneas of healthy participants were measured twice with a dual Scheimpflug instrument (Galilei G2), a scanning-slit system (Orbscan IIz), and a single Scheimpflug instrument (Pentacam HR). Height data describing the posterior corneal shape were fit with Zernike polynomials. Mean values with standard deviations (SD), test-retest variability (coefficient of repeatability [CoR]), and interdevice variability were determined for the defocus Z(2,0), astigmatism Z(2,-2) and Z(2,2), and higher-order terms coma Z(3,-1) and Z(3,1), trefoil Z(3,-3) and Z(3,3), and spherical aberration Z(4,0) coefficients for 5.5 mm and 8.0 mm diameters. RESULTS: For the 5.5 mm diameter, CoRs ranged from 0.3 to 4.3 µm with the dual Scheimpflug instrument, 1.6 to 5.2 µm with the scanning-slit system, and 0.3 to 2.0 µm with the single Scheimpflug instrument. The CoR was similar for the Scheimpflug instruments (P = .43) but poorer for the scanning-slit system (P < .001). The CoRs of the Scheimpflug instruments were smaller than the corresponding population SD for defocus, cardinal astigmatism, coma, and spherical aberration. The scanning-slit system failed to provide 8.0 mm diameter data. There was a significant bias (interdevice variability) between the Scheimpflug instruments in the higher-order coefficients at both diameters. CONCLUSIONS: Repeatability in assessing the posterior corneal shape was generally good for the Scheimpflug instruments but poor for the scanning-slit system. Interdevice variability between the Scheimpflug instruments compromised the interchangeability of higher-order coefficients. For astigmatism, CoR and 95% limits of agreement of the Scheimpflug instruments typically corresponded to 0.1 diopter per astigmatism term.

Identification of independent risk factors for flap failure: A retrospective analysis of 1530 free flaps for breast, head and neck and extremity reconstruction.

Reconstructive microsurgery is a powerful method of treating various complex defects. However, flap loss remains a possibility, leading to additional surgery, hospitalisation and costs. Consequently, it is important to know which factors lead to an increased risk of flap failure, so that measures can be undertaken to reduce this risk. Therefore, we analysed our results over a 20-year period to identify risk factors for flap failure after breast, head and neck and extremity reconstruction. The medical files of all patients treated between 1992 and 2012 were reviewed. Patient characteristics, surgical data and post-operative complications were scored, and independent risk factors for flap loss were identified. Reconstruction with a total of 1530 free flaps was performed in 1247 patients. Partial and total flap loss occurred in 5.5% and 4.4% of all free flaps, respectively. In all flaps, signs of compromised flap circulation were a risk factor for flap failure. More specifically, the risk factors for flap failure in breast reconstruction were previous radiotherapy, venous anastomosis revision, gluteal artery perforator (GAP) flap choice and post-operative bleeding. In head and neck reconstruction, pulmonary co-morbidity and anastomosis to the lingual vein or superficial temporal artery were risk factors, whereas a radial forearm flap reduced the risk. In extremity reconstruction, diabetes, prolonged anaesthesia time and post-operative wound infection were risk factors. Independent pre-, intra- and post-operative risk factors for flap failure after microvascular breast, head and neck and extremity reconstruction were identified. These results may be used to improve patient counselling and to adjust treatment algorithms to further reduce the chance of flap failure.

From corneal shape to ocular wavefront in eyes with aspheric IOLs: the feasibility of IOL customisation.

PURPOSE: To determine if it is possible to predict the ocular wavefront aberrations of eyes with an aspheric IOL from the corneal shape and other readily available eye characteristics. A reliable prediction is a prerequisite for future IOL customisation. METHODS: Sixty pseudophakic eyes with aspheric IOLs of 60 patients were included. The corneal shape and the ocular wavefront aberrations were measured postoperatively with a Scheimpflug camera and an aberrometer, respectively. The elevation data of the anterior corneal surface were fitted by Zernike polynomials. Linear regression models for the Zernike coefficients describing the ocular wavefront aberrations up till the fourth order were determined, with as independent variables the Zernike coefficients describing the corneal shape, the eye (right/left), IOL power, and axial length. RESULTS: Linear regression equations with an explained variance (adjusted R-square) above 0.50 were found for five Zernike aberration terms: defocus (z(2,0); adjusted R-square 0.90), the astigmatism terms (0.81 for oblique astigmatism [z(2,-2)] and 0.88 for regular astigmatism [z(2,2)]), vertical coma (z(3,-1); 0.52), and spherical aberration (z(4,0); 0.71). CONCLUSION: The defocus, astigmatism, vertical coma, and spherical aberration terms of the ocular wavefront are strongly associated with the corneal shape in pseudophakic eyes and may thus be predicted from the corneal shape and other eye characteristics.

Bone Grafts for Scaphoid Nonunion: An Overview.

The scaphoid is the most common fractured bone in the wrist. Despite adequate non-surgical treatment, around 10% to 15% of these fractures will not heal. Untreated scaphoid non-union can cause a scaphoid non-union advance collapse (SNAC), this is a progressive deformity and can cause degenerative changes in the wrist. Surgery is focused on achieving consolidation, pain reduction and a good position of the scaphoid while preventing osteoarthritis in the long-term. Surgery consists of reduction and fixation of the scaphoid with a non-vascularized or vascularized bone graft. An overview of the most used vascularized and non-vascularized bone grafts and their indications are presented.

Describing the corneal shape after wavefront-optimized photorefractive keratectomy.

PURPOSE: To develop a procedure for describing wavefront-optimized photorefractive keratectomy (PRK) corneas and to characterize PRK-induced changes in shape. METHODS: We analyzed preoperative and postoperative corneal elevation data of 41 eyes of 41 patients (mean [±SD] age, 38 [±11] years) who underwent a myopia-correcting (preoperative spherical equivalent refraction -3.9 [±1.5] diopters) wavefront-optimized PRK, assessed with Scheimpflug imaging. Zernike polynomials were fitted to the elevation data. The diameter of the greatest corneal zone that could be analyzed and the number of Zernike orders needed to make a reliable fit were determined, based on the fitting error. The PRK-induced changes in corneal shape were studied. RESULTS: All subjects could be included for analysis of zones up to 6 mm in diameter. This was 90, 83, and 44% for 7, 8, and 9 mm, respectively. The number of Zernike orders (terms) needed for an accurate fit ranged from four (15) for a 4-mm analyzed zone diameter to eight (45) for 8 mm. For the anterior surface, the spherical aberration term decreased significantly (p < 0.01) after PRK for the 4-mm analyzed zone diameter (-0.09 µm), remained unchanged for 5 mm (+0.01 µm; p = 0.56), and increased significantly for 6 mm (+0.40 µm) and above (p < 0.01). There was no significant change in any other higher-order Zernike term, but the square root of the sum of the squares of all higher-order terms increased significantly for all analyzed zone diameters. Photorefractive keratectomy did not influence the posterior corneal shape. CONCLUSIONS: The cornea after wavefront-optimized PRK can be described as accurately as a healthy cornea and with a similar number of Zernike polynomials. The anterior corneal shape changes significantly after treatment, whereas the posterior corneal shape remains unchanged. The observed effect of wavefront-optimized ablation on the spherical aberration term depends on the diameter of the analyzed zone.