Reducing blood product wastage through the inter-hospital redistribution of near-outdate inventory.

BACKGROUND: Hospital transfusion services order blood products to satisfy orders and maintain inventory levels during unexpected periods of increased blood demand. Surplus inventory may outdate before being allocated to a recipient. Blood product outdating is the largest contributor to blood wastage. STUDY DESIGN: A province-wide redistribution program was designed and implemented to redistribute near-outdate plasma protein and related blood products from low-usage to high-usage hospitals. Program operations and details are described in this paper. Two transport container configurations were designed and validated for transport of all blood products. A cost-analysis was performed to determine the effectiveness of this redistribution program. RESULTS: A total of 130 hospital transfusion services contributed at least one near-outdate blood product for redistribution between January 2012 and March 2020. These services redistributed 15,499 products through 3412 shipments, preventing the outdating of $17,570,700 CAD worth of product. Program costs were $14,900 for shipping and $30,000 for staffing. Failed time limits or non-compliance with packing configurations resulted in $388,200 worth of blood products (97 shipments containing 816 products) being discarded. Courier transport delays was the most common reason (42/97; 43%) for transport failure. CONCLUSION: Redistributing near-outdate blood products between hospitals is a feasible solution to minimize outdating. Despite heterogeneity of Canadian blood product inventory, all products (each with unique storage and transport requirements) were successfully redistributed in one of two validated and simple containers. Total operation costs of this program were small in comparison to the $17.6 million in savings associated with preventing the discard of outdated products.

The use of ketogenic diets in children living with drug-resistant epilepsy, glucose transporter 1 deficiency syndrome and pyruvate dehydrogenase deficiency: A scoping review.

BACKGROUND: The ketogenic diet (KD) is a high fat, moderate protein and very low carbohydrate diet. It can be used as a medical treatment for drug-resistant epilepsy (DRE), glucose transporter 1 deficiency syndrome and pyruvate dehydrogenase deficiency. The aim of this scoping review was to map the KD literature, with a focus on epilepsy and associated metabolic conditions, to summarise the current evidence-base and identify any gaps. METHODS: This review was conducted using JBI scoping review methodological guidance and the PRISMA extension for scoping reviews reporting guidance. A comprehensive literature search was conducted in September 2021 and updated in February 2024 using MEDLINE, CINAHL, AMED, EmBASE, CAB Abstracts, Scopus and Food Science Source databases. RESULTS: The initial search yielded 2721 studies and ultimately, data were extracted from 320 studies that fulfilled inclusion criteria for the review. There were five qualitative studies, and the remainder were quantitative, including 23 randomised controlled trials (RCTs) and seven quasi-experimental studies. The USA published the highest number of KD studies followed by China, South Korea and the UK. Most studies focused on the classical KD and DRE. The studies key findings suggest that the KD is efficacious, safe and tolerable. CONCLUSIONS: There are opportunities available to expand the scope of future KD research, particularly to conduct high-quality RCTs and further qualitative research focused on the child's needs and family support to improve the effectiveness of KDs.

How do I manage a blood product shortage?

BACKGROUND: The demand for blood products sometimes exceeds the available inventory. Blood product inventories are dependent upon the availability of donors, supplies and reagents, and collection staff. During prolonged extreme shortages, blood centers and transfusion services must alter practices to meet the needs of patients. STUDY DESIGN AND METHODS: The Association for the Advancement of Blood and Biotherapies Donor and Blood Component Management Subsection compiled some strategies from its blood center and hospital transfusion service members that could be implemented during blood product shortages. RESULTS: Some strategies that blood centers could use to increase their available inventories include increasing donor recruitment efforts, using alternate types of collection kits, manufacturing low-yield apheresis-derived platelets and/or whole blood-derived platelets, using cold-stored platelets, transferring inventory internally among centers of the same enterprise, using frozen inventory, decreasing standing order quantities, prioritizing allocation to certain patient populations, filling partial orders, and educating customers and blood center staff. Transfusion service strategies that could be implemented to maximize the use of the limited available inventory include increasing patient blood management efforts, using split units, finding alternate blood suppliers, trading blood products with other hospital transfusion services, developing a patient priority list, assembling a hospital committee to decide on triaging priorities, using expired products in extreme situations, and accepting nonconforming products after performing safety checks. DISCUSSION: Blood centers and transfusion services must choose the appropriate strategies to implement based on their needs.

Patient and carer perspectives on the use of video consultations in the management of the ketogenic diet for epilepsy.

BACKGROUND: The COVID-19 pandemic resulted in a significant change in the way healthcare was delivered worldwide. During this time, a survey of Ketogenic Dietitians Research Network (KDRN) members found that all respondents expected digital platforms for clinics and/or education to continue post-pandemic. As a follow-up to this, we surveyed views about video consultations (VCs) of patients and carers of those following the ketogenic diet for drug-resistant epilepsy. METHODS: The SurveymonkeyTM survey was distributed on Matthews' Friends and KDRN social media platforms and emailed from five United Kingdom ketogenic diet centers to their patients/carers. RESULTS: Forty eligible responses were received. More than half of the respondents (23, 57.5%) had attended a VC. Eighteen respondents (45%) would like to have VCs for most (categorized as approximately 75%) or all of their consultations. Half as many (9, 22.5%) would not like video consultations. The most common benefits selected were saving travel time (32, 80%), less stress of finding somewhere to park and not having to take time off work (22, 55% each). Twelve (30%) responded that VCs lessened environmental impact. The most common disadvantages selected were not being able to get blood tests/having to make a separate consultation for blood tests (22, 55% overall), not being able to get weight or height checked/having to make a separate consultation for this and it is less personal/preferring face-to-face (17, 42.5% each). Three-quarters (30 respondents) felt it would be very easy or easy to accurately weigh the patient when not attending an in-person consultation. CONCLUSION: Our results suggest that many patients and carers would welcome the option of VCs as well as face-to-face consultations. Where possible and appropriate patients and their families should be offered both options. This is in line with the NHS Long-Term Plan and the NHS response to climate change.

Evaluating the appropriateness of platelet transfusions compared with evidence-based platelet guidelines: An audit of platelet transfusions at 57 hospitals.

BACKGROUND: Platelet transfusions are used to prevent or control bleeding in patients with thrombocytopenia or platelet dysfunction. The pretransfusion platelet count threshold has been studied extensively in multiple patient settings yielding high-quality evidence that has been summarized in several comprehensive evidence-based platelet guidelines. STUDY DESIGN AND METHODS: A prospective 12-week audit of consecutive platelet transfusions using validated and evidence-based adjudication criteria was conducted. Patient demographic, laboratory, and transfusion details were collected with an electronic audit tool. Each order was adjudicated either electronically or independently by two transfusion medicine physicians. The aim was to determine platelet transfusion appropriateness and common scenarios with deviations from guidelines. RESULTS: Fifty-seven (38%) of 150 hospitals provided data on 1903 platelet orders, representing 90% of platelet usage in the region during the time period. Overall, 702 of 1693 adult (41.5%) and 133 of 210 pediatric orders (63.3%) were deemed inappropriate. The most common inappropriate platelet order was for prophylaxis in the absence of bleeding or planned procedure in patients with hypoproliferative thrombocytopenia and a platelet count over 10 x 109 /L (53% of inappropriate orders in adults and 45% in pediatrics). Platelet transfusions ordered with either a preprinted transfusion order set (odds ratio [OR], 1.97; 95% confidence interval [CI], 1.44-2.73) or technologist prospective screening (OR, 1.40; 95% CI, 1.10-1.78) were more likely to be appropriate. CONCLUSION: There is a discrepancy between clinical practice and evidence-based platelet guidelines. Broad educational and system changes will be needed to align platelet transfusion practice with guideline recommendations.

Do we need more patient-friendly treatment options for overactive bladder (OAB)?

AIMS: To collect feedback from subjects diagnosed with overactive bladder (OAB) on its impact on their quality of life, their satisfaction with current treatment options, and to assess nonsurgical, tibial nerve stimulation as a treatment option. METHODS: Subjects were asked a variety of questions about the impact of OAB on their lives, their satisfaction with current and previous treatment approaches. Subjects evaluated the comfort of a nonworking prototype garment and were given electrical stimulation over their posterior tibial nerve to assess comfort and tolerability. Electromyographic (EMG) signals were recorded. RESULTS: A total of 40 subjects with OAB symptoms were evaluated in the study. Urgency (55%), frequency (47.5%), nocturia (40%), and incontinence (30%) were the most bothersome symptoms. At the time of the study only 32.5% of the subjects were treating their OAB symptoms. Of those that had tried and discontinued treatments, most had failed medications (n = 14) due to no improvements or side effects. Only 2 subjects found stimulation to be uncomfortable before an EMG signal could be detected. The most common word used to describe the feeling of stimulation was "constant," followed by "tingling," "vibrating," and "comfortable." CONCLUSIONS: Most subjects who had tried OAB treatments were dissatisfied and discontinued their use. A new patient-friendly approach to OAB therapy that delivers efficacy but overcomes drawbacks associated with currently available treatments is needed. Subjects found electrical stimulation over the tibial nerve to be comfortable and tolerable and this should be considered as an alternative treatment approach for OAB.

Patterns of early literacy and word reading skill development across the first 6 months of school and reading instruction.

This study described the growth trajectories of 105 children (n = 55 boys) who had just started primary school in New Zealand (NZ). Children were assessed every fourth school week around 1.5 months after starting school, for five sessions on Dynamic Indicators of Basic Early Literacy Skills first sound fluency (FSF), AIMSweb letter sound fluency (LSF), and a newly created NZ word identification fluency (NZWIF-Y1), designed for alignment with beginning reading instruction in NZ. In addition to progress monitoring tasks, children were assessed at school entry and after progress monitoring on literacy-related criterion measures. All three progress monitoring measures were sensitive to growth over the children's first 6 months of school. Cross-sectional time-series analyses indicated that within-child increases in FSF and LSF were associated with increases in NZWIF-Y1, although FSF did not add unique variance when both FSF and LSF were entered as predictors. Furthermore, growth mixture modeling indicated three latent growth trajectories for each indicator (FSF, LSF, NZWIF-Y1, respectively): Class 1-high initial scores and strong growth over time (72.09%, 55.87%, 22.81%); Class 2-lower initial scores and moderate growth over time (19.18%, 29.12%, 54.30%); and Class 3-low initial scores and limited progress over time (8.73%, 15.00%, 22.89%). Criterion measures assessed prior and after progress monitoring were typically associated with latent class membership. Results suggest relative growth in performance on repeated assessment of early literacy and word reading skills in beginning reading instruction distinguishes groups of students with differential skill acquisition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Tolerance, adherence, and acceptability of a ketogenic 2.5:1 ratio, nutritionally complete, medium chain triglyceride-containing liquid feed in children and adults with drug-resistant epilepsy following a ketogenic diet.

OBJECTIVE: To investigate incorporating a ready-to-use 2.5:1 ratio liquid feed into a ketogenic diet (KD) in children and adults with drug-resistant epilepsy. METHODS: Following a three-day baseline, patients (n = 19; age: 19 years [SD 13], range: 8-46 years) followed a KD for 28 days (control period), then incorporated ≥200 mL/day of a ready-to-use liquid feed, made with a ratio of 2.5 g of fat to 1 g of protein plus carbohydrate and including medium chain triglycerides ([MCTs]; 25.6% of total fat/100 mL) for 28 days as part of their KD (intervention period). Outcome measures (control vs intervention period) included gastrointestinal (GI) tolerance, adherence to KD and intervention feed, dietary intake, blood ß-hydroxybutyrate (BHB) concentration, seizure outcomes, health-related quality of life (HRQoL), acceptability and safety. RESULTS: Compared to the control period, during the intervention period, the percentage of patients reporting no GI symptoms increased (+5% [SD 5], p = 0.02); adherence to the KD prescription was similar (p = 0.92) but higher in patients (n = 5) with poor adherence (<50%) to KD during the control period (+33% [SD 26], p = 0.049); total MCT intake increased (+12.1 g/day [SD 14.0], p = 0.002), driven by increases in octanoic (C8; +8.3 g/day [SD 6.4], p < 0.001) and decanoic acid (C10; +5.4 g/day [SD 5.4], p < 0.001); KD ratio decreased (p = 0.047), driven by a nonsignificant increase in protein intake (+11 g/day [SD 44], p = 0.29); seizure outcomes were similar (p ≥ 0.63) but improved in patients (n = 6) with the worst seizure outcomes during the control period (p = 0.04); and HRQoL outcomes were similar. The intervention feed was well adhered to (96% [SD 8]) and accepted (≥88% of patients confirmed). SIGNIFICANCE: These findings provide an evidence-base to support the effective management of children and adults with drug-resistant epilepsy following a KD with the use of a ready-to-use, nutritionally complete, 2.5:1 ratio feed including MCTs. PLAIN LANGUAGE SUMMARY: This study examined the use of a ready-to-use, nutritionally complete, 2.5:1 ratio (2.5 g of fat to 1 g of protein plus carbohydrate) liquid feed, including medium chain triglycerides (MCTs), into a ketogenic diet (KD) in children and adults with drug-resistant epilepsy. The results show that the 2.5:1 ratio feed was well tolerated, adhered to, and accepted in these patients. Increases in MCT intake (particularly C8 and C10) and improvements in seizure outcomes (reduced seizure burden and intensity) and KD adherence also occurred with the 2.5:1 ratio feed in patients with the worst seizures and adherence, respectively.

School-entry skills and early skill trajectories predict reading after 1 year.

Oral language and early literacy skills are theorized to provide the foundation for reading acquisition. To understand these relations, methods are needed that depict dynamic skill development in the context of reading acquisition. We modeled contributions of school-entry skills and early skill trajectories to later reading with 105 5-year-old children beginning primary school and formal literacy instruction in New Zealand. Children were assessed at school-entry (Preschool Early Literacy Indicators), followed every fourth school week over their first 6 months of school (five probes of First Sound Fluency, Letter Sound Fluency, and New Zealand Word Identification Fluency: Year 1), and after 1 year of school (researcher-administered and school-used indices of literacy-related skills and reading progress). Modified latent change score (mLCS) modeling was used to describe skill development from repeated progress-monitoring data. Ordinal regression and structural equation modeling (path analyses) indicated skills at school-entry and early learning trajectories, indexed by mLCS, predicted children's early literacy progress. Results have implications for research and screening in beginning reading, supporting school-entry screening and progress monitoring of early literacy skills in beginning reading acquisition. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Aggression towards clinicians within Opiate Substitution Treatment (OST) services: A survey of service providers.

Background: High levels of aggression towards staff in healthcare settings have been reported. It seems likely that workers in Opioid Substitution Therapy (OST) would be at increased risk of adverse events and their consequences. Objectives: This study aimed to establish if practitioners who provide OST are experiencing negative outcomes, specifically aggression, distress, and burnout, and to identify if workload and professional affiliation were associated with these risks. Methods: A survey was conducted of OST practitioners in a single geographical region of New Zealand (population approx. 344,000). The survey asked for demographics (including caseloads), Perception of Patient Aggression Scale New Zealand Revision (POPAS-NZ), Kessler 10 (K10), Short Post-Traumatic Stress Disorder Rating Interview (SPRINT), and Abbreviated Maslach Burnout Inventory (aMBI) and two qualitative questions asking about the best and worst aspects of working in OST. Results: All recorded OST workers in the region (n = 181) were invited to participate, 95 practitioners responded to the survey (52.4%). This group included pharmacists, doctors, nurses, social workers and addiction workers. Results indicated aggression, distress, and burnout were being experienced by practitioners. Number of patients seen by a practitioner significantly increased risk of aggression (F(1,90) = 14.14, p < 0.001). Psychiatrists were the most at risk profession (p = 0.016). Burnout responses were high for around 20% of practitioners, with low numbers meeting criteria for distress and PTSD. Positive things about working in OST were relationships with patients, appreciating patient outcomes and positive team environments. Negative aspects were patient behaviours, maintaining empathy, and, administration tasks. Conclusions: Aggression was a workplace hazard for OST clinicians. Low rates of distress and PTSD symptoms were reported and some evidence of practitioner burnout. Practitioners reported positive relationships, making a difference and teamwork may have been improving this area of mental health work.

Electric parameters optimization in spinal cord stimulation. Study in conventional nonrechargeable systems.

BACKGROUND: Spinal cord stimulation devices provide a means of creating an electric field. The parameters used to produce this electric field are: pulse amplitude, pulse width (Pw), and pulse frequency (F). AIMS: The purpose is to document the effects that the various stimulus parameters have on patient perception of paresthesia and the relationship that this perception has on pain relief. METHODS: Stimulus parameters were varied independently keeping the electrode polarity constant while recording stimulation thresholds. The Pw was varied from 195 to 300 µ sec while maintaining the frequency at 50 Hz. The F was varied from 10 to 100 Hz while maintaining the Pw at 300 µ sec. We also measured the paresthesia coverage percentage and the subjective perception of quality reported by the patients with each one of the parameter changes. RESULTS: There was a statistically significant correlation between Pw and all the stimulation thresholds. As for the therapeutic range, the differences observed also were statistically significant. Pw variation did not produce significant differences in coverage and subjective quality of the paresthesia. The perception threshold did not vary significantly with F changes. However, F significantly affected both coverage of the painful area and paresthesia perception quality. CONCLUSIONS: In the usual Pw ranges, it seems that its usefulness is limited to obtaining finer adjustments in the stimulation amplitude. Frequency management may be significantly useful to get a wider coverage of the stimulated area.

Describing patterns of early literacy skill development in the first year of school and reading instruction in a New Zealand sample.

This study describes trajectories of early literacy skill development of 99 children (n = 55 boys) in their first year of primary school in New Zealand (NZ). Children were assessed twice weekly for 8 weeks on Dynamic Indicators of Basic Early Literacy Skills (DIBELS; Good & Kaminski, 2011) First Sound Fluency (FSF) and AIMSweb Letter Sound Fluency (LSF; Shinn & Shinn, 2002), with other early literacy and beginning reading skills assessed before and after progress monitoring. FSF and LSF growth trajectories were modeled separately. Multilevel modeling indicated improved performance; however, growth mixture modeling indicated 3 growth trajectories (i.e., latent classes; FSF and LSF, respectively): typical (77.6% of children, 65.7%), developing (10.8%, 14.6%), and limited progress (11.6%, 19.7%). Beginning of year screening was sometimes associated with latent class membership, whereas latent class membership differentiated mid- and year-end literacy skills. Results support progress monitoring of early literacy skills within the NZ context to aid earlier identification of children at-risk for difficulties with reading acquisition. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Identification of arm movements using correlation of electrocorticographic spectral components and kinematic recordings.

The purpose of this study was to explore the possibility of using electrocorticographic (ECoG) recordings from subdural electrodes placed over the motor cortex to identify the upper limb motion performed by a human subject. More specifically, we were trying to identify features in the ECoG signals that could help us determine the type of movement performed by an individual. Two subjects who had subdural electrodes implanted over the motor cortex were asked to perform various motor tasks with the upper limb contralateral to the site of electrode implantation. ECoG signals and upper limb kinematics were recorded while the participants were performing the movements. ECoG frequency components were identified that correlated well with the performed movements measured along 6D coordinates (X, Y, Z, roll, yaw and pitch). These frequencies were grouped using histograms. The resulting histograms had consistent and unique shapes that were representative of individual upper limb movements performed by the participants. Thus, it was possible to identify which movement was performed by the participant without prior knowledge of the arm and hand kinematics. To confirm these findings, a nearest neighbour classifier was applied to identify the specific movement that each participant had performed. The achieved classification accuracy was 89%.

Technology for Peripheral Nerve Stimulation.

Peripheral nerve stimulation (PNS) has been in use for over 50 years to treat patients suffering from chronic pain who have failed conservative treatments. Despite this long history, the devices being used have changed very little. In fact, current PNS technology was developed specifically for spinal cord stimulation. The use of technology developed for other applications in PNS has led to an unnecessary number of device complications and the limited adoption of this promising therapy. The following chapter provides an overview of PNS technology throughout the years, outlining both the benefits and limitations. We will briefly explore the electrophysiology of PNS stimulation, with an emphasis on technology and indication-specific devices. Finally, design and technical requirements of an ideal PNS device will be discussed.

Near-infrared spectroscopy reveals link between chronic physical activity and anterior frontal oxygenated hemoglobin in healthy young women.

Cerebrovascular and cognitive functioning peak developmentally in young adults, yet recent evidence indicates they may benefit on these fronts from regular engagement in physical activity. In light of epidemiological trends for increasingly sedentary lifestyles and the importance of optimal cerebrovascular and cognitive functioning, here we investigated relationships between physical activity levels, anterior frontal hemodynamics, and cognitive performance in 52 healthy young women. Analyses positively linked chronic physical activity level (CPAL) with anterior frontal oxygenated hemoglobin and cognitive inhibitory control, indicating regular physical activity may lead to hemodynamic and cognitive benefits, even in a cohort at developmental peak. In addition, higher anterior frontal oxygenated hemoglobin was linked to better performance for the most difficult cognitive task. Given the importance of oxygen availability for cognitive functioning, the current discovery of a relationship with CPAL may provide important insight toward understanding exercise-cognition links.

Safety and efficacy of spinal cord stimulation for the treatment of chronic pain: a 20-year literature review.

OBJECT: The purpose of this report was to examine the available literature to determine the safety and efficacy of spinal cord stimulation (SCS) for the treatment of chronic pain of the trunk and limbs. METHODS: The author identified 68 studies that fulfilled the efficacy inclusion/exclusion criteria, grouped on the basis of pain indication, with an overall population of 3679 patients. Fifty-one studies fulfilled all safety inclusion/exclusion criteria. Based on the literature review, the author found that SCS had a positive, symptomatic, long-term effect in cases of refractory angina pain, severe ischemic limb pain secondary to peripheral vascular disease, peripheral neuropathic pain, and chronic low-back pain, and that, in general, SCS was a safe and effective treatment for a variety of chronic neuropathic conditions. CONCLUSIONS: Despite the positive findings, there is an urgent need for randomized, controlled, long-term studies on the efficacy of SCS involving larger patient sample sizes.

Neurotoxicity screening test for deep brain stimulation leads.

A description of qualitative and quantitative cell-culture studies using in vitro human cerebellar, cortical and glial cell lines developed to screen a deep brain stimulation lead for neurotoxicity potential is presented. Preclinical neurotoxicity testing requirements for implantable medical devices have historically been met by expensive long-term large animal testing. To decrease large animal killing, expense and time to human trials, an in vitro human tissue testing process was developed and compared to standard animal testing. A permanently implantable deep brain stimulation lead was subjected to both qualitative and quantitative cell culture studies using in vitro human cerebellar, cortical and glial cell lines. Materials were extracted in both saline (72 h at 50 degrees C) and minimum essential medium (24 h at 37 degrees C) environments. All cytotoxicity and cell proliferation testing resulted in positive controls (Tygon) F-4040-A) showing severe cytotoxicity in all cell lines, negative controls (high-density polyethylene) and both extraction media above showing non-cytotoxic results in all cell lines. In vitro human neuronal cell specific cytotoxicity testing in combination with ISO-10993 biological and materials characterization testing is an efficient, practical means of screening a device for preclinical safety for use in humans.

Evolving patterns of spinal cord stimulation in patients implanted for intractable low back and leg pain.

The objective of this study was to examine the programming strategies used in patients with intractable low-back pain treated with epidural spinal cord stimulation (SCS) utilizing paddle electrodes and a radio frequency (RF) stimulator. Programming strategies were examined in a group of patients implanted with a 16-contact paddle electrode and a dual channel RF receiver to treat chronic low-back pain. Baseline data included previous surgical history information, leg and low back pain severity and characteristics, and routine demographic information. Outcome measurements included the visual analog scale (VAS) (1), patient pain relief rating scale, and programming parameters. Patients rated their pain relief on a 5-point scale where 4 = excellent, 3 = good, 2 = fair, 1 = poor and 0 = none. Success was determined to be a pain relief score of "fair" or above. Data were collected during patient visits or by mail, at approximately 6, 12, and 24 months, postoperatively. Immediate postop data were available in 16 patients, 6-month data in 21 patients, 1-year data in 20 patients, and 2-year data in 10 patients, and analyzed for the purposes of examining programming strategies. The most common location for the tip of the electrode (lead) was found to be in the middle of the 8th thoracic vertebrae (N = 26). At the immediate postop assessment, the majority of cathodes were activated in the upper half of T9. By the 6-month follow-up, the majority of cathodes had shifted to the bottom of T9 and top of T10. Overall 88% of cathode locations were changed at one or more study visits. At 2 years, 86% of the programs used four or more active contacts. At 6 months, 83% of the patients reported that the therapy was a success, at 1 year, success was 94%, and by 2 years, success was 75%. Both SCS and chronic pain are dynamic processes. Complex pain patterns, such as the ones of patients who have pain in the low back and in one or both lower extremities, require a high degree of flexibility in the implanted SCS system. The system must provide the capability to redirect the current electronically over at least two segments of the spinal canal, to electronically steer the current in a medio-lateral direction, and to activate multiple electrical contacts simultaneously. The willingness and ability to provide extensive reprogramming in the long term follow-up is also of the utmost importance. Pain and its treatment with SCS is a dynamic process.

Operating principles and clinical implications of constant flow pumps.

Intrathecal drug therapy has become an indispensable tool in the treatment of many different neurologic disorders. It allows targeted infusion of small quantities of drugs, thereby increasing effectiveness while reducing unwanted side effects typically seen in oral drug administration. The following paper discusses the current technology in constant rate intrathecal drug-infusion delivery systems and the effect of pressure and temperature on flow rate accuracy.