Andre Wolff - Academia.edu (original) (raw)

Papers by Andre Wolff

Patient Safety in Surgery, 2014

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2015

ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a t... more ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a thin Al2O3 tunnel barrier, and graphene top electrode are fabricated. Due to the monolayered graphene top electrode, the electrons are able to tunnel through the Al2O3 layer and emit into the vacuum. The temperature behavior of the tunnel leakage current as well as the emission current is characterized. (C) 2015 American Vacuum Society.


Patient Safety in Surgery, 2014

Implementation Science, 2015

BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital... more BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital and patient level of an evidence-based strategy to improve the use of Dutch perioperative safety guidelines. Based on current knowledge, expert opinions and expertise of the project team, a multifaceted implementation strategy has been developed.Methods/designThis is a stepped wedge cluster randomized trial including nine representative hospitals across The Netherlands. Hospitals are stratified into three groups according to hospital type and geographical location and randomized in terms of the period for receipt of the intervention. All adult surgical patients meeting the inclusion criteria are assessed for patient outcomes. The implementation strategy includes education, audit and feedback, organizational interventions (e.g., local embedding of the guidelines), team-directed interventions (e.g., multi-professional team training), reminders, as well as patient-mediated interventions (e.g., patient safety cards). To tailor the implementation activities, we developed a questionnaire to identify barriers for effective guideline adherence, based on (a) a theoretical framework for classifying barriers and facilitators, (b) an instrument for measuring determinants of innovations, and (c) 19 semi-structured interviews with perioperative key professionals. Primary outcome is guideline adherence measured at the hospital (i.e., cluster) and patient levels by a set of perioperative Patient Safety Indicators (PSIs), which was developed parallel to the perioperative guidelines. Secondary outcomes at the patient level are in-hospital complications, postoperative wound infections and mortality, length of hospital stay, and unscheduled transfer to the intensive care unit, non-elective readmission to the hospital and unplanned reoperation, all within 30 days after the initial surgery. Also, patient safety culture and team climate will be studied as potential determinants. Finally, a process evaluation is conducted to identify the compliance with the implementation strategy, as well as an economic evaluation to assess the costs. Data sources are registered clinical data and surveys. There is no form of blinding.DiscussionThe perioperative setting is an unexplored area with respect to implementation issues. This study is expected to yield important new evidence about the effects of a multifaceted approach on guideline adherence in the perioperative care setting.Trial registrationDutch trial registry: NTR3568.

Pijn Info, 2004

Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast... more Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast bij patiënten met lage-rugpijn en uitstraling naar het been om het niveau van de aandoening en de erbij betrokken zenuwen te bepalen.

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2015

ABSTRACT Chemical vapor deposition (CVD) was applied to grow dielectric HfO2 layers on graphene/S... more ABSTRACT Chemical vapor deposition (CVD) was applied to grow dielectric HfO2 layers on graphene/SiO2/Si and graphene/TiN/Si reference substrates directly, i.e., without a seed layer or any other functionalization of graphene. It was found that the presence of bilayer and (generally) multilayer graphene islands on nominally monolayer graphene strongly impacts the nucleation and the growth of HfO2. No damage inflicted by the CVD process on the graphene could be detected by Raman spectroscopy. According to x-ray diffraction, the films, grown on graphene at 400 °C and having thickness between 5 and 50 nm, were polycrystalline. Electrical measurements were performed for metal–insulator–metal (MIM) capacitors produced by evaporating Au and TiN top electrodes on the HfO2 film. Leakage currents were in the range of 10−8 A/cm2 at 1 V for 50 nm HfO2 grown on graphene, exceeding by one order of magnitude the currents measured for the reference HfO2/TiN MIM structures. The films grown on graphene have a dielectric constant of 17 with a quality factor of 50.

According to Clinical Diagnoses, 2011

... 31 Another study, however, did demonstrate diminished pain intensity with gabapentin in com .... more ... 31 Another study, however, did demonstrate diminished pain intensity with gabapentin in com ... 43. Hayes C , Armstrong - Brown A , Burstal R. Perioperative intravenous ketamine infusion for the ... 48. Becotte A , de Medicis E , Martin R , Gagnon V. Continuous sciatic nerve block in ...

Regional Anesthesia and Pain Medicine, 2001

Selective spinal nerve infiltration blocks are used diagnostically in patients with chronic low b... more Selective spinal nerve infiltration blocks are used diagnostically in patients with chronic low back pain radiating into the leg. Generally, a segmental nerve block is considered successful if the pain is reduced substantially. Hypesthesia and elicited paresthesias coinciding with the presumed segmental level are used as controls. The interpretation depends on a standard dermatomal map. However, it is not clear if this interpretation is reliable enough, because standard dermatomal maps do not show the overlap of neighboring dermatomes. The goal of the present study is to establish if dissimilarities exist between areas of hypesthesia, spontaneous pain reported by the patient, pain reduction by local anesthetics, and paresthesias elicited by sensory electrostimulation. A secondary goal is to determine to what extent the interpretation is improved when the overlaps of neighboring dermatomes are taken into account. Patients suffering from chronic low back pain with pain radiating into the leg underwent lumbosacral segmental nerve root blocks at subsequent levels on separate days. Lidocaine (2%, 0.5 mL) mixed with radiopaque fluid (0.25 mL) was injected after verifying the target location using sensory and motor electrostimulation. Sensory changes (pinprick method), paresthesias (reported by the patient), and pain reduction (Numeric Rating Scale) were reported. Hypesthesia and paresthesias were registered in a standard dermatomal map and in an adapted map which included overlap of neighboring dermatomes. The relationships between spinal level of injection, extent of hypesthesia, location of paresthesias, and corresponding dermatome were assessed quantitatively. Comparison of the results between both dermatomal maps was done by paired t-tests. After inclusion, data were processed for 40 segmental nerve blocks (L2-S1) performed in 29 patients. Pain reduction was achieved in 43%. Hypesthetic areas showed a large variability in size and location, and also in comparison to paresthesias. Mean hypesthetic area amounted 2.7 +/- 1.4 (+/- SD: range, 0 to 6; standard map) and 3.6 +/- 1.8 (0 to 6; adapted map; P <.001) dermatomes. In these cases, hypesthesia in the corresponding dermatome was found in 80% (standard map) and 88% of the cases (adapted map, not significant). Paresthesias occurring in the corresponding dermatome were found in 80% (standard map) compared with 98% (adapted map, P <.001). In 85% (standard map) and 88% (adapted map), spontaneous pain was present in the dermatome corresponding to the level of local anesthetic injection. In 55% (standard map) versus 75% (adapted map, P <.005), a combination of spontaneous pain, hypesthesia, and paresthesias was found in the corresponding dermatome. Hypesthetic areas determined after lumbosacral segmental nerve blocks show a large variability in size and location compared with elicited paresthesias. Confirmation of an adequately performed segmental nerve block, determined by coexistence of hypesthesia, elicited paresthesias and pain in the presumed dermatome, is more reliable when the overlap of neighboring dermatomes is taken into account.

Patient Safety in Surgery, 2014

Regional Anesthesia and Pain Medicine, 2006

In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) ... more In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) are performed to predict surgical outcome and identify the putative symptomatic spinal nerve. Epidural spread may lead to false interpretation, affecting clinical decision making. Systematic fluoroscopic analysis of epidural local anesthetic spread and its relationship to needle tip location has not been published to date. Study aims include assessment of epidural local anesthetic spread and its relationship to needle position during fluoroscopy-assisted blocks. Patients scheduled for L4, L5, and S1 blocks were included in this prospective observational study. Under fluoroscopy and electrostimulation, they received 0.5 mL of a mixture containing lidocaine 5 mg and iohexol 75 mg. X-rays with needle tip and contrast were scored for no epidural spread (grade 0), local spread epidurally (grade 1), or to adjacent nerve roots (grade 2). Sixty-five patients were analyzed for epidural spread, 62 for needle position. Grade 1 epidural spread occurred in 47% of L4 and 28% of L5 blocks and grade 2 spread in 3 blocks (5%; L5 n = 1, S1 n = 2). For lumbar blocks, the needle was most frequently found in the lateral upper half of the intervertebral foramen. Epidural spread occurred more frequently with medial needle positions (P = .06). The findings suggest (P = .06) that the risk of grade 1 and 2 lumbar epidural spread, which results in decreased SNRB selectivity, is greater with medial needle positions in the intervertebral foramen. The variability in anatomic position of the dorsal root ganglion necessitates electrostimulation to guide SNRB in addition to fluoroscopy.

Japanese Journal of Applied Physics, 1997

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2015

ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a t... more ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a thin Al2O3 tunnel barrier, and graphene top electrode are fabricated. Due to the monolayered graphene top electrode, the electrons are able to tunnel through the Al2O3 layer and emit into the vacuum. The temperature behavior of the tunnel leakage current as well as the emission current is characterized. (C) 2015 American Vacuum Society.


Patient Safety in Surgery, 2014

Regional Anesthesia and Pain Medicine, 2006

In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) ... more In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) are performed to predict surgical outcome and identify the putative symptomatic spinal nerve. Epidural spread may lead to false interpretation, affecting clinical decision making. Systematic fluoroscopic analysis of epidural local anesthetic spread and its relationship to needle tip location has not been published to date. Study aims include assessment of epidural local anesthetic spread and its relationship to needle position during fluoroscopy-assisted blocks. Patients scheduled for L4, L5, and S1 blocks were included in this prospective observational study. Under fluoroscopy and electrostimulation, they received 0.5 mL of a mixture containing lidocaine 5 mg and iohexol 75 mg. X-rays with needle tip and contrast were scored for no epidural spread (grade 0), local spread epidurally (grade 1), or to adjacent nerve roots (grade 2). Sixty-five patients were analyzed for epidural spread, 62 for needle position. Grade 1 epidural spread occurred in 47% of L4 and 28% of L5 blocks and grade 2 spread in 3 blocks (5%; L5 n = 1, S1 n = 2). For lumbar blocks, the needle was most frequently found in the lateral upper half of the intervertebral foramen. Epidural spread occurred more frequently with medial needle positions (P = .06). The findings suggest (P = .06) that the risk of grade 1 and 2 lumbar epidural spread, which results in decreased SNRB selectivity, is greater with medial needle positions in the intervertebral foramen. The variability in anatomic position of the dorsal root ganglion necessitates electrostimulation to guide SNRB in addition to fluoroscopy.

Implementation Science, 2015

BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital... more BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital and patient level of an evidence-based strategy to improve the use of Dutch perioperative safety guidelines. Based on current knowledge, expert opinions and expertise of the project team, a multifaceted implementation strategy has been developed.Methods/designThis is a stepped wedge cluster randomized trial including nine representative hospitals across The Netherlands. Hospitals are stratified into three groups according to hospital type and geographical location and randomized in terms of the period for receipt of the intervention. All adult surgical patients meeting the inclusion criteria are assessed for patient outcomes. The implementation strategy includes education, audit and feedback, organizational interventions (e.g., local embedding of the guidelines), team-directed interventions (e.g., multi-professional team training), reminders, as well as patient-mediated interventions (e.g., patient safety cards). To tailor the implementation activities, we developed a questionnaire to identify barriers for effective guideline adherence, based on (a) a theoretical framework for classifying barriers and facilitators, (b) an instrument for measuring determinants of innovations, and (c) 19 semi-structured interviews with perioperative key professionals. Primary outcome is guideline adherence measured at the hospital (i.e., cluster) and patient levels by a set of perioperative Patient Safety Indicators (PSIs), which was developed parallel to the perioperative guidelines. Secondary outcomes at the patient level are in-hospital complications, postoperative wound infections and mortality, length of hospital stay, and unscheduled transfer to the intensive care unit, non-elective readmission to the hospital and unplanned reoperation, all within 30 days after the initial surgery. Also, patient safety culture and team climate will be studied as potential determinants. Finally, a process evaluation is conducted to identify the compliance with the implementation strategy, as well as an economic evaluation to assess the costs. Data sources are registered clinical data and surveys. There is no form of blinding.DiscussionThe perioperative setting is an unexplored area with respect to implementation issues. This study is expected to yield important new evidence about the effects of a multifaceted approach on guideline adherence in the perioperative care setting.Trial registrationDutch trial registry: NTR3568.

European Journal of Pain, 2006

Pijn Info, 2004

Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast... more Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast bij patiënten met lage-rugpijn en uitstraling naar het been om het niveau van de aandoening en de erbij betrokken zenuwen te bepalen.

Patient Safety in Surgery, 2014

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2015

ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a t... more ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a thin Al2O3 tunnel barrier, and graphene top electrode are fabricated. Due to the monolayered graphene top electrode, the electrons are able to tunnel through the Al2O3 layer and emit into the vacuum. The temperature behavior of the tunnel leakage current as well as the emission current is characterized. (C) 2015 American Vacuum Society.


Patient Safety in Surgery, 2014

Implementation Science, 2015

BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital... more BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital and patient level of an evidence-based strategy to improve the use of Dutch perioperative safety guidelines. Based on current knowledge, expert opinions and expertise of the project team, a multifaceted implementation strategy has been developed.Methods/designThis is a stepped wedge cluster randomized trial including nine representative hospitals across The Netherlands. Hospitals are stratified into three groups according to hospital type and geographical location and randomized in terms of the period for receipt of the intervention. All adult surgical patients meeting the inclusion criteria are assessed for patient outcomes. The implementation strategy includes education, audit and feedback, organizational interventions (e.g., local embedding of the guidelines), team-directed interventions (e.g., multi-professional team training), reminders, as well as patient-mediated interventions (e.g., patient safety cards). To tailor the implementation activities, we developed a questionnaire to identify barriers for effective guideline adherence, based on (a) a theoretical framework for classifying barriers and facilitators, (b) an instrument for measuring determinants of innovations, and (c) 19 semi-structured interviews with perioperative key professionals. Primary outcome is guideline adherence measured at the hospital (i.e., cluster) and patient levels by a set of perioperative Patient Safety Indicators (PSIs), which was developed parallel to the perioperative guidelines. Secondary outcomes at the patient level are in-hospital complications, postoperative wound infections and mortality, length of hospital stay, and unscheduled transfer to the intensive care unit, non-elective readmission to the hospital and unplanned reoperation, all within 30 days after the initial surgery. Also, patient safety culture and team climate will be studied as potential determinants. Finally, a process evaluation is conducted to identify the compliance with the implementation strategy, as well as an economic evaluation to assess the costs. Data sources are registered clinical data and surveys. There is no form of blinding.DiscussionThe perioperative setting is an unexplored area with respect to implementation issues. This study is expected to yield important new evidence about the effects of a multifaceted approach on guideline adherence in the perioperative care setting.Trial registrationDutch trial registry: NTR3568.

Pijn Info, 2004

Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast... more Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast bij patiënten met lage-rugpijn en uitstraling naar het been om het niveau van de aandoening en de erbij betrokken zenuwen te bepalen.

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2015

ABSTRACT Chemical vapor deposition (CVD) was applied to grow dielectric HfO2 layers on graphene/S... more ABSTRACT Chemical vapor deposition (CVD) was applied to grow dielectric HfO2 layers on graphene/SiO2/Si and graphene/TiN/Si reference substrates directly, i.e., without a seed layer or any other functionalization of graphene. It was found that the presence of bilayer and (generally) multilayer graphene islands on nominally monolayer graphene strongly impacts the nucleation and the growth of HfO2. No damage inflicted by the CVD process on the graphene could be detected by Raman spectroscopy. According to x-ray diffraction, the films, grown on graphene at 400 °C and having thickness between 5 and 50 nm, were polycrystalline. Electrical measurements were performed for metal–insulator–metal (MIM) capacitors produced by evaporating Au and TiN top electrodes on the HfO2 film. Leakage currents were in the range of 10−8 A/cm2 at 1 V for 50 nm HfO2 grown on graphene, exceeding by one order of magnitude the currents measured for the reference HfO2/TiN MIM structures. The films grown on graphene have a dielectric constant of 17 with a quality factor of 50.

According to Clinical Diagnoses, 2011

... 31 Another study, however, did demonstrate diminished pain intensity with gabapentin in com .... more ... 31 Another study, however, did demonstrate diminished pain intensity with gabapentin in com ... 43. Hayes C , Armstrong - Brown A , Burstal R. Perioperative intravenous ketamine infusion for the ... 48. Becotte A , de Medicis E , Martin R , Gagnon V. Continuous sciatic nerve block in ...

Regional Anesthesia and Pain Medicine, 2001

Selective spinal nerve infiltration blocks are used diagnostically in patients with chronic low b... more Selective spinal nerve infiltration blocks are used diagnostically in patients with chronic low back pain radiating into the leg. Generally, a segmental nerve block is considered successful if the pain is reduced substantially. Hypesthesia and elicited paresthesias coinciding with the presumed segmental level are used as controls. The interpretation depends on a standard dermatomal map. However, it is not clear if this interpretation is reliable enough, because standard dermatomal maps do not show the overlap of neighboring dermatomes. The goal of the present study is to establish if dissimilarities exist between areas of hypesthesia, spontaneous pain reported by the patient, pain reduction by local anesthetics, and paresthesias elicited by sensory electrostimulation. A secondary goal is to determine to what extent the interpretation is improved when the overlaps of neighboring dermatomes are taken into account. Patients suffering from chronic low back pain with pain radiating into the leg underwent lumbosacral segmental nerve root blocks at subsequent levels on separate days. Lidocaine (2%, 0.5 mL) mixed with radiopaque fluid (0.25 mL) was injected after verifying the target location using sensory and motor electrostimulation. Sensory changes (pinprick method), paresthesias (reported by the patient), and pain reduction (Numeric Rating Scale) were reported. Hypesthesia and paresthesias were registered in a standard dermatomal map and in an adapted map which included overlap of neighboring dermatomes. The relationships between spinal level of injection, extent of hypesthesia, location of paresthesias, and corresponding dermatome were assessed quantitatively. Comparison of the results between both dermatomal maps was done by paired t-tests. After inclusion, data were processed for 40 segmental nerve blocks (L2-S1) performed in 29 patients. Pain reduction was achieved in 43%. Hypesthetic areas showed a large variability in size and location, and also in comparison to paresthesias. Mean hypesthetic area amounted 2.7 +/- 1.4 (+/- SD: range, 0 to 6; standard map) and 3.6 +/- 1.8 (0 to 6; adapted map; P <.001) dermatomes. In these cases, hypesthesia in the corresponding dermatome was found in 80% (standard map) and 88% of the cases (adapted map, not significant). Paresthesias occurring in the corresponding dermatome were found in 80% (standard map) compared with 98% (adapted map, P <.001). In 85% (standard map) and 88% (adapted map), spontaneous pain was present in the dermatome corresponding to the level of local anesthetic injection. In 55% (standard map) versus 75% (adapted map, P <.005), a combination of spontaneous pain, hypesthesia, and paresthesias was found in the corresponding dermatome. Hypesthetic areas determined after lumbosacral segmental nerve blocks show a large variability in size and location compared with elicited paresthesias. Confirmation of an adequately performed segmental nerve block, determined by coexistence of hypesthesia, elicited paresthesias and pain in the presumed dermatome, is more reliable when the overlap of neighboring dermatomes is taken into account.

Patient Safety in Surgery, 2014

Regional Anesthesia and Pain Medicine, 2006

In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) ... more In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) are performed to predict surgical outcome and identify the putative symptomatic spinal nerve. Epidural spread may lead to false interpretation, affecting clinical decision making. Systematic fluoroscopic analysis of epidural local anesthetic spread and its relationship to needle tip location has not been published to date. Study aims include assessment of epidural local anesthetic spread and its relationship to needle position during fluoroscopy-assisted blocks. Patients scheduled for L4, L5, and S1 blocks were included in this prospective observational study. Under fluoroscopy and electrostimulation, they received 0.5 mL of a mixture containing lidocaine 5 mg and iohexol 75 mg. X-rays with needle tip and contrast were scored for no epidural spread (grade 0), local spread epidurally (grade 1), or to adjacent nerve roots (grade 2). Sixty-five patients were analyzed for epidural spread, 62 for needle position. Grade 1 epidural spread occurred in 47% of L4 and 28% of L5 blocks and grade 2 spread in 3 blocks (5%; L5 n = 1, S1 n = 2). For lumbar blocks, the needle was most frequently found in the lateral upper half of the intervertebral foramen. Epidural spread occurred more frequently with medial needle positions (P = .06). The findings suggest (P = .06) that the risk of grade 1 and 2 lumbar epidural spread, which results in decreased SNRB selectivity, is greater with medial needle positions in the intervertebral foramen. The variability in anatomic position of the dorsal root ganglion necessitates electrostimulation to guide SNRB in addition to fluoroscopy.

Japanese Journal of Applied Physics, 1997

Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2015

ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a t... more ABSTRACT Graphene based electron field emitter arrays consisting of cone-shaped silicon tips, a thin Al2O3 tunnel barrier, and graphene top electrode are fabricated. Due to the monolayered graphene top electrode, the electrons are able to tunnel through the Al2O3 layer and emit into the vacuum. The temperature behavior of the tunnel leakage current as well as the emission current is characterized. (C) 2015 American Vacuum Society.


Patient Safety in Surgery, 2014

Regional Anesthesia and Pain Medicine, 2006

In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) ... more In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) are performed to predict surgical outcome and identify the putative symptomatic spinal nerve. Epidural spread may lead to false interpretation, affecting clinical decision making. Systematic fluoroscopic analysis of epidural local anesthetic spread and its relationship to needle tip location has not been published to date. Study aims include assessment of epidural local anesthetic spread and its relationship to needle position during fluoroscopy-assisted blocks. Patients scheduled for L4, L5, and S1 blocks were included in this prospective observational study. Under fluoroscopy and electrostimulation, they received 0.5 mL of a mixture containing lidocaine 5 mg and iohexol 75 mg. X-rays with needle tip and contrast were scored for no epidural spread (grade 0), local spread epidurally (grade 1), or to adjacent nerve roots (grade 2). Sixty-five patients were analyzed for epidural spread, 62 for needle position. Grade 1 epidural spread occurred in 47% of L4 and 28% of L5 blocks and grade 2 spread in 3 blocks (5%; L5 n = 1, S1 n = 2). For lumbar blocks, the needle was most frequently found in the lateral upper half of the intervertebral foramen. Epidural spread occurred more frequently with medial needle positions (P = .06). The findings suggest (P = .06) that the risk of grade 1 and 2 lumbar epidural spread, which results in decreased SNRB selectivity, is greater with medial needle positions in the intervertebral foramen. The variability in anatomic position of the dorsal root ganglion necessitates electrostimulation to guide SNRB in addition to fluoroscopy.

Implementation Science, 2015

BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital... more BackgroundThis study is initiated to evaluate the effects, costs, and feasibility at the hospital and patient level of an evidence-based strategy to improve the use of Dutch perioperative safety guidelines. Based on current knowledge, expert opinions and expertise of the project team, a multifaceted implementation strategy has been developed.Methods/designThis is a stepped wedge cluster randomized trial including nine representative hospitals across The Netherlands. Hospitals are stratified into three groups according to hospital type and geographical location and randomized in terms of the period for receipt of the intervention. All adult surgical patients meeting the inclusion criteria are assessed for patient outcomes. The implementation strategy includes education, audit and feedback, organizational interventions (e.g., local embedding of the guidelines), team-directed interventions (e.g., multi-professional team training), reminders, as well as patient-mediated interventions (e.g., patient safety cards). To tailor the implementation activities, we developed a questionnaire to identify barriers for effective guideline adherence, based on (a) a theoretical framework for classifying barriers and facilitators, (b) an instrument for measuring determinants of innovations, and (c) 19 semi-structured interviews with perioperative key professionals. Primary outcome is guideline adherence measured at the hospital (i.e., cluster) and patient levels by a set of perioperative Patient Safety Indicators (PSIs), which was developed parallel to the perioperative guidelines. Secondary outcomes at the patient level are in-hospital complications, postoperative wound infections and mortality, length of hospital stay, and unscheduled transfer to the intensive care unit, non-elective readmission to the hospital and unplanned reoperation, all within 30 days after the initial surgery. Also, patient safety culture and team climate will be studied as potential determinants. Finally, a process evaluation is conducted to identify the compliance with the implementation strategy, as well as an economic evaluation to assess the costs. Data sources are registered clinical data and surveys. There is no form of blinding.DiscussionThe perioperative setting is an unexplored area with respect to implementation issues. This study is expected to yield important new evidence about the effects of a multifaceted approach on guideline adherence in the perioperative care setting.Trial registrationDutch trial registry: NTR3568.

European Journal of Pain, 2006

Pijn Info, 2004

Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast... more Segmentale zenuwblokkaden worden voor diagnostische doeleinden diagnostische doeleinden toegepast bij patiënten met lage-rugpijn en uitstraling naar het been om het niveau van de aandoening en de erbij betrokken zenuwen te bepalen.