Margriet G. Mullender
VU University Medical Center
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Featured researches published by Margriet G. Mullender.
The Journal of Sexual Medicine | 2015
Sophie E.R. Horbach; Mark-Bram Bouman; Jan Maerten Smit; Müjde Özer; Marlon E. Buncamper; Margriet G. Mullender
INTRODUCTIONnGender reassignment surgery is the keystone of the treatment of transgender patients. For male-to-female transgenders, this involves the creation of a neovagina. Many surgical methods for vaginoplasty have been opted. The penile skin inversion technique is the method of choice for most gender surgeons. However, the optimal surgical technique for vaginoplasty in transgender women has not yet been identified, as outcomes of the different techniques have never been compared.nnnAIMnWith this systematic review, we aim to give a detailed overview of the published outcomes of all currently available techniques for vaginoplasty in male-to-female transgenders.nnnMETHODSnA PubMed and EMBASE search for relevant publications (1995-present), which provided data on the outcome of techniques for vaginoplasty in male-to-female transgender patients.nnnMAIN OUTCOME MEASURESnMain outcome measures are complications, neovaginal depth and width, sexual function, patient satisfaction, and improvement in quality of life (QoL).nnnRESULTSnTwenty-six studies satisfied the inclusion criteria. The majority of these studies were retrospective case series of low to intermediate quality. Outcome of the penile skin inversion technique was reported in 1,461 patients, bowel vaginoplasty in 102 patients. Neovaginal stenosis was the most frequent complication in both techniques. Sexual function and patient satisfaction were overall acceptable, but many different outcome measures were used. QoL was only reported in one study. Comparison between techniques was difficult due to the lack of standardization.nnnCONCLUSIONSnThe penile skin inversion technique is the most researched surgical procedure. Outcome of bowel vaginoplasty has been reported less frequently but does not seem to be inferior. The available literature is heterogeneous in patient groups, surgical procedure, outcome measurement tools, and follow-up. Standardized protocols and prospective study designs are mandatory for correct interpretation and comparability of data.
The Journal of Sexual Medicine | 2014
Mark-Bram Bouman; Michiel C.T. van Zeijl; Marlon E. Buncamper; W. J. H. J. Meijerink; Ad A. van Bodegraven; Margriet G. Mullender
INTRODUCTIONnVaginal (re)construction is essential for the psychological well-being of biological women with a dysfunctional vagina and male-to-female transgender women. However, the preferred method for vagina (re)construction with respect to functional as well as aesthetic outcomes is debated. Regarding intestinal vaginoplasty, despite the asserted advantages, the need for intestinal surgery and subsequent risk of diversion colitis are often-mentioned concerns. The outcomes of vaginal reconstructive surgery need to be appraised in order to improve understanding of pros and cons.nnnAIMSnTo review literature on surgical techniques and clinical outcomes of intestinal vaginoplasty.nnnMETHODSnElectronic databases and reference lists of published articles were searched for primary studies on intestinal vaginoplasty. Studies were included if these included at least five patients and had a minimal follow-up period of 1 year. No constraints were imposed with regard to patient age, indication for vaginoplasty, or applied surgical technique. Outcome measures were extracted and analyzed.nnnMAIN OUTCOME MEASURESnMain outcome measures were surgical procedure, clinical outcomes, and outcomes concerning sexual health and quality of life.nnnRESULTSnTwenty-one studies on intestinal vaginoplasty were included (including 894 patients in total). All studies had a retrospective design and were of low quality. Prevalence and severity of procedure-related complications were low. The main postoperative complication was introital stenosis, necessitating surgical correction in 4.1% of sigmoid-derived and 1.2% of ileum-derived vaginoplasties. Neither diversion colitis nor cancer was reported. Sexual satisfaction rate was high, but standardized questionnaires were rarely used. Quality of life was not reported.nnnCONCLUSIONnBased on evidence presently available, it seems that intestinal vaginoplasty is associated with low complication rates. To substantiate these findings and to obtain information about functional outcomes and quality of life, prospective studies using standardized measures and questionnaires are warranted.
Spine | 2005
A.J. van der Veen; Margriet G. Mullender; Theo H. Smit; I. Kingma; J.H. van Dieen
Study Design. An in vitro mechanical study on porcine motion segments. Objectives. To test the validity of in vitro studies of the flow-related mechanics of the intervertebral disc and, in particular, to investigate whether fluid flows back into the disc during unloading after a loading cycle. Summary of Background Data. In vivo studies show both the inflow and outflow of fluid in the intervertebral disc. The resistance to flow out of the disc is higher than to inflow. The fluid flow is regulated via unbalance between the external load and the osmotic pressure of the nucleus pulposus. Materials. There were 8 porcine lumbar motion segments (without posterior elements) and 8 isolated discs tested in a physiologic saline bath (39°C). The specimens were preloaded at 0.025 MPa for 15 minutes. Three 15-minute loading periods at 2.0 MPa were applied, each followed by an unloading period of 30 minutes. Loads, axial displacements, and nucleus pressure were recorded online. Results. Over the 3 loading and unloading periods, all specimens showed a net loss of height and mass. The time series of specimen height during the 3 unloading periods showed virtually identical responses. The pressure in the nucleus decreased in the subsequent loading periods and showed no increase during unloading. Conclusion. The data show the limitations of an in vitro model for studying fluid flow-related intervertebral disc mechanics. During loading, outflow of fluid occurred, but inflow appears to be virtually absent during unloading. Poro-elastic behavior cannot be reproduced in an in vitro model.
Journal of Biomechanics | 2008
Albert J. van der Veen; Margriet G. Mullender; Idsart Kingma; Jaap H. van; Theo H. Smit
Spinal segments show non-linear behavior under axial compression. It is unclear to what extent this behavior is attributable to the different components of the segment. In this study, we quantified the separate contributions of vertebral bodies and intervertebral discs to creep of a segment. Secondly, we investigated the contribution of bone and osteochondral endplate (endplates including cartilage) to the deformation of the vertebral body. From eight porcine spines a motion segment, a disc and a vertebral body were dissected and subjected to mechanical testing. In an additional test, cylindrical samples, machined from the lowest thoracic vertebrae of 11 porcine spines, were used to compare the deformation of vertebral bone and endplate. All specimens were subjected to three loading cycles, each comprising a loading phase (2.0 MPa, 15 min) and a recovery phase (0.001 MPa, 30 min). All specimens displayed substantial time-dependent height changes. Average creep was the largest in motion segments and smallest in vertebral bodies. Bone samples with endplates displayed substantially more creep than samples without. In the early phase, behavior of the vertebra was similar to that of the disc. Visco-elastic deformation of the endplate therefore appeared dominant. In the late creep phase, behavior of the segment was similar to that of isolated discs, suggesting that in this phase the disc dominated creep behavior, possibly by fluid flow from the nucleus. We conclude that creep deformation of vertebral bodies contributes substantially to creep of motion segments and that within a vertebral body endplates play a major role.
European Spine Journal | 2012
Arno Bisschop; Margriet G. Mullender; Idsart Kingma; Timothy U. Jiya; Albert J. van der Veen; Jan C. Roos; Jaap H. van Dieën; Barend J. van Royen
PurposeLaminectomy is a standard surgical procedure for elderly patients with symptomatic degenerative lumbar stenosis. The procedure aims at decompression of the affected nerves, but it also causes a reduction of spinal shear strength and shear stiffness. The magnitude of this reduction and the influence of bone mineral density (BMD) and disc degeneration are unknown. We studied the influence of laminectomy, BMD, and disc degeneration on shear force to failure (SFF) and shear stiffness (SS).MethodsTen human cadaveric lumbar spines were obtained (mean age 72.1xa0years, range 53–89xa0years). Laminectomy was performed either on L2 or L4, equally divided within the group of ten spines. BMD was assessed by dual X-ray absorptiometry (DXA). Low BMD was defined as a BMD value below the median. Intervertebral discs were assessed for degeneration by MRI (Pfirrmann) and scaled in mild and severe degeneration groups. Motion segments L2–L3 and L4–L5 were isolated from each spine. SFF and SS were measured, while loading simultaneously with 1,600xa0N axial compression.ResultsLow BMD had a significant negative effect on SFF. In addition, a significant interaction between low BMD and laminectomy was found. In the high BMD group, SFF was 2,482xa0N (range 1,678–3,284) and decreased to 1,371xa0N (range 940–1,886) after laminectomy. In the low BMD group, SFF was 1,339xa0N (range 909–1,628) and decreased to 761xa0N (range 561–1,221). Disc degeneration did not affect SFF, nor did it interact with laminectomy. Neither low BMD nor the interaction of low BMD and laminectomy did affect SS. Degeneration and its interaction with laminectomy did not significantly affect SS.ConclusionsIn conclusion, low BMD significantly decreased SFF before and after lumbar laminectomy. Therefore, DXA assessment may be an important asset to preoperative screening. Lumbar disc degeneration did not affect shear properties of lumbar segments before or after laminectomy.
European Spine Journal | 2010
A. A. Benjamin de Vries; Margriet G. Mullender; Winand J. Pluymakers; René M. Castelein; Barend J. van Royen
Due to the aging population, degenerative scoliosis is a growing clinical problem. It is associated with back pain and radicular symptoms. The pathogenesis of degenerative scoliosis lies in degenerative changes of the spinal structures, such as the intervertebral disc, the facet joints and the vertebrae itself. Possibly muscle weakness also plays a role. However, it is not clear what exactly causes the decompensation to occur and what determines the direction of the curve. It is known that in the normal spine a pre-existing rotation exists at the thoracic level, but not at the lumbar level. In this retrospective study we have investigated if a predominant curve pattern can be found in degenerative scoliosis and whether symptoms are predominantly present at one side relative to the curve direction. The lumbar curves of 88 patients with degenerative scoliosis were analyzed and symptoms were recorded. It was found that curve direction depended significantly on the apical level of the curve. The majority of curves with an apex above L2 were convex to the right, whereas curves with an apex below L2 were more frequently convex to the left. This would indicate that also in degenerative scoliosis the innate curvature and rotational pattern of the spine plays a role in the direction of the curve. Unilateral symptoms were not coupled to the curve direction. It is believed that the symptoms are related to local and more specific degenerative changes besides the scoliotic curve itself.
Journal of Plastic Reconstructive and Aesthetic Surgery | 2016
Jan Willem Groen; Vera L. Negenborn; D.J.W.R. Twisk; Dimitris Rizopoulos; J.L. Ket; Jan Maerten Smit; Margriet G. Mullender
OBJECTIVEnThis study presents an up-to-date overview of the literature on autologous fat grafting (AFG) in onco-plastic breast reconstruction, with respect to complications, oncological and radiological safety, volume retention and patient/surgeon satisfaction.nnnBACKGROUNDnAlthough AFG is increasingly being applied in onco-plastic breast reconstruction, a comprehensive overview of the available evidence for this procedure is still lacking.nnnMETHODSnA systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was conducted. Case series, cohort studies and randomized controlled trials (RCTs) reporting on relevant outcomes of breast reconstruction with supplemental AFG were included.nnnRESULTSnIn total, 43 studies were included reporting on 6260 patients with a follow-up period ranging from 12 to 136 months. The average locoregional and distant oncological recurrence rates after breast reconstruction with AFG were 2.5% (95% confidence interval (CI) 1.7-3.7) and 2.0% (95% CI 1.1-3.5), respectively. Fewer cysts and calcifications were seen on radiological images for this procedure than for other types of breast surgery. However, more biopsies were performed based on radiological findings (3.7% vs. 1.6%), and more cases of fat necrosis (9.0% vs 4.7%) were seen after treatment with AFG. The total complication rate of 8.4% (95% CI 7.6-9.1) is lower than those reported following other reconstructive breast procedures. The mean volume retention was 76.8% (range 44.7-82.6%) with a satisfaction rate of 93.4% for patients and 90.1% for surgeons.nnnCONCLUSIONSnAFG in breast reconstruction is a promising technique. Safety is not compromised as cancer recurrence and complications are not observed. Whether AFG interferes with radiological follow-up remains to be elucidated. Randomized trials with sound methodology are needed to confirm these conclusions.
The Journal of Sexual Medicine | 2016
Tim C. van de Grift; Baudewijntje P.C. Kreukels; Lian Elfering; Müjde Özer; Mark-Bram Bouman; Marlon E. Buncamper; Jan Maerten Smit; Margriet G. Mullender
INTRODUCTIONnTransmen are generally dissatisfied with their breasts and often opt for mastectomy. However, little is known about the specific effects of this procedure on this groups body image.nnnAIMnTo prospectively assess the effect of mastectomy on the body image of transmen, including cognitive, emotional, and behavioral aspects.nnnMETHODSnDuring a 10-month period, all transmen applying for mastectomy were invited to participate in this study. The 33 participants completed assessments preoperatively and at least 6 months postoperatively.nnnMAIN OUTCOME MEASURESnParticipants were surveyed on body satisfaction (Body Image Scale for Transsexuals), body attitudes (Multidimensional Body-Self Relations Questionnaire), appearance schemas (Appearance Schemas Inventory), situational bodily feelings (Situational Inventory of Body Image Dysphoria), body image-related quality of life (Body Image Quality of Life Inventory), and self-esteem (Rosenberg Self-Esteem Scale). Control values were retrieved from the literature and a college sample.nnnRESULTSnBefore surgery, transmen reported less positive body attitudes and satisfaction, a lower self-esteem and body image-related quality of life compared with cisgender men and women. Mastectomy improved body satisfaction most strongly, although respondents reported improvements in all domains (eg, decreased dysphoria when looking in the mirror and improved feelings of self-worth). Most outcome measurements were strongly correlated.nnnCONCLUSIONnMastectomy improves body image beyond satisfaction with chest appearance alone. Body satisfaction and feelings of passing in social situations are associated with a higher quality of life and self-esteem.
Knee | 2008
T. Kraal; Margriet G. Mullender; J.H.D. de Bruine; R. Reinhard; A. de Gast; D.J. Kuik; B.J. van Royen
The open-wedge high tibial osteotomy (OWHTO) is a well accepted treatment modality for patients with osteoarthritis of the medial compartment associated with genu varum. To fill in the osteotomy gap 30% macroporosity rigid beta-tricalcium phosphate (beta-TCP) is frequently used as a stable resorbable bone substitute. However, the resorbability of these beta-TCP wedges is not known. The aim of this study was to investigate this. Twenty-one OWHTO procedures in seventeen patients were performed with the use of 30% macroporosity rigid beta-TCP wedges. The osteotomies were fixed using an angle-stable locking plate. Conventional AP and lateral radiographs were examined in order to assess the resorbability of the 30% macroporosity rigid beta-TCP wedges as a function of time. A radiological classification system consisting of five phases was used to monitor the resorption of the 30% macroporosity rigid beta-TCP wedges. The mean duration of follow-up was 62 months (+/-23 range of 28-99). In all 21 cases, remnants of the 30% macroporosity rigid beta-TCP wedges were still present at maximum follow-up. Although the boundaries between 30% macroporosity rigid beta-TCP wedges and bone remained slightly visible, all osteotomies were completely consolidated and full osseointegration took place. In 16 out of 21 knees the fixation system was removed after a mean duration of 32 months (+/-19 range of 6-62). In six out of 21 knees a conversion to a knee arthroplasty was performed after a mean duration of 56 months (+/-18 range of 37-82). The OWHTO did not interfere with the placement of knee prostheses. Complete resorption of 30% macroporosity rigid beta-TCP wedges did not take place up to 8 years after operation.
Journal of Hand Surgery (European Volume) | 2015
Merel J.L. Berkhout; Yara Bachour; Kang He Zheng; Margriet G. Mullender; Simon D. Strackee; Marco J.P.F. Ritt
PURPOSEnTo compare the long-term outcomes of proximal row carpectomy (PRC) and 4-corner arthrodesis (FCA) in a consecutive series of patients surgically treated between 1989 and 1998 in a single teaching hospital.nnnMETHODSnWe included 12 patients (14 wrists) in the PRC group and 8 patients (8 wrists) in the FCA group. Mean follow-up time was 17 years. We compared functional outcome measures (range of motion and grip strength) and patient-reported outcome measures (visual analog score for pain, Mayo Wrist Score, and Michigan Hand Questionnaire). Radiographic evaluation of joint degeneration using the Culp and Jebson scoring system and postoperative complications were assessed for both groups.nnnRESULTSnActive range of motion was slightly better after PRC. There were no differences in grip strength and patient-reported outcomes between groups. Severity of degenerative changes did not differ between groups and was not correlated with pain scores. The FCA group showed more postoperative complications.nnnCONCLUSIONSnConsidering the objective and patient-reported outcomes of this study, both types of surgery perform well in the long run. Proximal row carpectomy seems to result in slightly better movement of the wrist with fewer surgical complications and no need for hardware removal. Moreover, postoperative immobilization time was much shorter.nnnTYPE OF STUDY/LEVEL OF EVIDENCEnTherapeutic III.