Hypothetical Advantages Research Articles

Tolerability of vortioxetine compared to selective serotonin reuptake inhibitors in older adults with major depressive disorder (VESPA): a randomised, assessor-blinded and statistician-blinded, multicentre, superiority trial

Major depressive disorder (MDD) is prevalent and disabling among older adults. Standing on its tolerability profile, vortioxetine might be a promising alternative to selective serotonin reuptake inhibitors (SSRIs) in such a vulnerable population. We conducted a randomised, assessor- and statistician-blinded, superiority trial including older adults with MDD. The study was conducted between 02/02/2019 and 02/22/2023 in 11 Italian Psychiatric Services. Participants were randomised to vortioxetine or one of the SSRIs, selected according to common practice. Treatment discontinuation due to adverse events after six months was the primary outcome, for which we aimed to detect a 12% difference in favour of vortioxetine. The study was registered in the online repository clinicaltrials.gov (NCT03779789). The intention-to-treat population included 179 individuals randomised to vortioxetine and 178 to SSRIs. Mean age was 73.7 years (standard deviation 6.1), and 264 participants (69%) were female. Of those on vortioxetine, 78 (44%) discontinued the treatment due to adverse events at six months, compared to 59 (33%) of those on SSRIs (odds ratio 1.56; 95% confidence interval 1.01-2.39). Adjusted and per-protocol analyses confirmed point estimates in favour of SSRIs, but without a significant difference. With the exception of the unadjusted survival analysis showing SSRIs to outperform vortioxetine, secondary outcomes provided results consistent with a lack of substantial safety and tolerability differences between the two arms. Overall, no significant differences emerged in terms of response rates, depressive symptoms and quality of life, while SSRIs outperformed vortioxetine in terms of cognitive performance. As opposed to what was previously hypothesised, vortioxetine did not show a better tolerability profile compared to SSRIs in older adults with MDD in this study. Additionally, hypothetical advantages of vortioxetine on depression-related cognitive symptoms might be questioned. The study's statistical power and highly pragmatic design allow for generalisability to real-world practice. The study was funded by the Italian Medicines Agency within the "2016 Call for Independent Drug Research".

Soft selection reduces loss of heterozygosity in asexual reproduction.

The adaptive value of sexual reproduction is still debated in evolutionary theory. It has been proposed that the advantage of sexual reproduction over asexual reproduction is to promote genetic diversity, to prevent the accumulation of harmful mutations or to preserve heterozygosity. Since these hypothetical advantages depend on the type of asexual reproduction, understanding how selection affects the taxonomic distribution of each type could help us discriminate between existing hypotheses. Here, I argue that soft selection, competition among embryos or offspring in selection arenas prior to the hard selection of the adult phase, reduces loss of heterozygosity in certain types of asexual reproduction. Since loss of heterozygosity leads to the unmasking of recessive deleterious mutations in the progeny of asexual individuals, soft selection facilitates the evolution of these types of asexual reproduction. Using a population genetics model, I calculate how loss of heterozygosity affects fitness for different types of apomixis and automixis, and I show that soft selection significantly reduces loss of heterozygosity, hence increases fitness, in apomixis with suppression of the first meiotic division and in automixis with central fusion, the most common types of asexual reproduction. Therefore, if sexual reproduction evolved to preserve heterozygosity, soft selection should be associated with these types of asexual reproduction. I discuss the evidence for this prediction and how this and other observations on the distribution of different types of asexual reproduction in nature is consistent with the heterozygosity hypothesis.

Continuous polyhydroxybutyrate production from biogas in an innovative two-stage bioreactor configuration.

Biogas biorefineries have opened up new horizons beyond heat and electricity production in the anaerobic digestion sector. Added-value products such as polyhydroxyalkanoates (PHAs), which are environmentally benign and potential candidates to replace conventional plastics, can be generated from biogas. This work investigated the potential of an innovative two-stage growth-accumulation system for the continuous production of biogas-based polyhydroxybutyrate (PHB) using Methylocystis hirsuta CSC1 as cell factory. The system comprised two turbulent bioreactors in series to enhance methane and oxygen mass transfer: a continuous stirred tank reactor (CSTR) and a bubble column bioreactor (BCB) with internal gas recirculation. The CSTR was devoted to methanotrophic growth under nitrogen balanced growth conditions and the BCB targeted PHB production under nitrogen limiting conditions. Two different operational approaches under different nitrogen loading rates and dilution rates were investigated. A balanced nitrogen loading rate along with a dilution rate (D) of 0.3 day-1 resulted in the most stable operating conditions and a PHB productivity of ~53 g PHB m-3 day-1 . However, higher PHB productivities (~127 g PHB m-3 day-1 ) were achieved using nitrogen excess at a D = 0.2 day-1 . Overall, the high PHB contents (up to 48% w/w) obtained in the CSTR under theoretically nutrient balanced conditions and the poor process stability challenged the hypothetical advantages conferred by multistage vs single-stage process configurations for long-term PHB production.

Children’s group identity is related to their assessment of fair and unfair advantages

Unfair advantages can be created either intentionally (e.g., cheating) or unintentionally (e.g., unintended benefit). Little is known regarding how children evaluate different types of advantages in situations where group identity and group membership are made salient. To investigate how children’s group identity influences their evaluations and attribution of intentions in intergroup contexts, children were presented with three hypothetical advantages (unintentionally unfair, intentionally unfair, and fair) in a competitive context created by either an in-group member or an out-group member. Children (N = 120) were 4–6 years of age (n = 59; Mage = 5.29 years) and 7–10 years of age (n = 61; Mage = 8.34 years), including 64 girls and 56 boys. Participants were 67% European American, 18% African American, 11% Asian American, and 4% Hispanic. All participants were assigned to one of two teams in a contest in order to create an in-group/out-group manipulation prior to their evaluation of the actions. Out-group members viewed unintentional unfair and fair advantages as less acceptable than in-group members, but in-group and out-group members were equally negative in their assessment of an intentional transgression. When reasoning about unintentional and intentional unfair advantages, older children referenced the intentions of the advantage creator to justify their decisions more than younger children, whereas younger children reasoned about the impact of the behavior on their team more than older children. These novel findings shed light on developmental and social factors influencing children’s understanding of fairness and intentionality in everyday contexts.

Highs and lows in laparoscopic pancreaticoduodenectomy

IntroductionLaparoscopic pancreaticoduodenectomy (PD) is not widely accepted, and its use is controversial. Only correct patient selection and appropriate training of groups experienced in pancreatic surgery and laparoscopy will be able to establish its role and its hypothetical advantages. MethodsOut of 138 pancreatic surgeries performed in a two-year period (2017–2019), 23 were laparoscopic PD. We evaluate its efficacy and safety compared to 31 open PD. ResultsThere were no cases of B/C pancreatic or biliary fistula, nor any cases of delayed gastric emptying in the laparoscopic group, but hemorrhage required one reoperation. The conversion rate was 21% (five cases): one due to bleeding, and the remainder for non-progression. The converted patients showed no differences compared to those completed by laparoscopy. There were no differences between laparoscopic and open PD in surgical time, postoperative complications, reintervention rate, readmissions or mortality. R0 resection in tumor cases was 85% for laparoscopy and 69% in open surgery without statistical significance. The postoperative hospital stay was shorter in the laparoscopic PD group (eight vs. 15 days). ConclusionsIn a selected group, laparoscopic PD can be safely and effectively performed if carried out by groups who are experts in pancreatic surgery and advanced laparoscopy. The technique has the same postoperative results as open surgery and is oncologically adequate, with less hospital stay. Proper patient selection, a step-by-step program and a lax and early conversion prevents serious operating accidents.

Consequences appraisal on India’s opting out of the Regional Comprehensive Economic Partnership Agreement

The political and economic context for India based on the results of the Regional Comprehensive Economic Partnership Agreement (RCEP) signed in November 2020 is considered. The benefits of strengthening economic cooperation for the participating countries from its signing are characterized. The hypothetical advantages for India in the case of its entry into RCEP are analyzed. In connection with country’s opting out of RCEP the authors have highlighted three segments of reasons for studying (political, legal and economic) that caused such India’s decision. Among the political reasons for India’s opting out of RCEP the problem of the Indo-Chinese border conflict over disputed territory escalating is emphasized. Among the legal reasons that determined opting out of the treaty, the issues of investment policy and intellectual property outside the World Trade Organization frameworks are noted. The economic reasons offset the benefits of RCEP for India are investigated. The connection between all three segments of causes is demonstrated. The experts’ forecasts is evaluated for India’s entry into third place in the world economy in terms of the gross domestic product contribution and the prerequisites for this are studied. It is concluded about the possibility of achieving the goal if a number of conditions are met and a set of necessary measures is carried out.

Rectal spacer hydrogel in 1.5T MR-guided and daily adapted SBRT for prostate cancer: dosimetric analysis and preliminary patient-reported outcomes.

The main aim of the current analysis was to explore the hypothetical advantages using rectal spacer during 1.5T MR-guided and daily adapted prostate cancer stereotactic body radiotherapy (SBRT) compared to a no-rectal spacer hydrogel cohort of patients. The SBRT-protocol consisted of a 35 Gy schedule delivered in 5 fractions. Herein, we present a dosimetric analysis between spacer and no-spacer patients. Furthermore, treatment tolerability and feasibility were preliminarily assessed according to clinicians-reported outcomes at the end of treatment and patient-reported outcomes measures (PROMs) in both arms. Toxicity and quality of life were assessed at baseline and after treatment using the Common Terminology Criteria for Adverse Events v. 5.0, International Prostatic Symptoms Score, ICIQ-SF, IIEF-5, and EORTC-QLQ-C30 and PR-25 questionnaires. 120 plans (pre- and daily adaptive SBRT planning) were analyzed in 20 patients (10 patients in spacer group and 10 patients in no-spacer group) treated using 1.5T MR-guided adaptive SBRT. Statistically significant dosimetric advantages were observed in favor of the spacer insertion, improving the planning target volume coverage in terms of V33.2Gy >95% and planning target volume 37.5 Gy <2% mainly during daily-adapted SBRT. Also, rectum V32, V28 and V18Gy and bladder V35Gy <1 cc were significantly reduced in the spacer cohort. Concerning the PROMS, all questionnaires showed no difference between the pre- and post-SBRT evaluation in both arms, excepting the physical functioning item of EORTC QLQ-C30 questionnaire that was declined in the no-spacer group. These preliminary results strongly suggest the adoption of perirectal spacer due to dosimetric advantages not only for rectal sparing but also for target coverage. Longer follow-up is required to validate the clinical impact in terms of clinicians-reported toxicity and PROMs. This the first experience reporting preliminary data concerning the potential dosimetric impact of rectal hydrogel spacer on MR-guided SBRT for prostate cancer.

Luces y sombras de la duodenopancreatectomía cefálica laparoscópica

IntroductionLaparoscopic pancreaticoduodenectomy (PD) is not widely accepted, and its use is controversial. Only correct patient selection and appropriate training of groups experienced in pancreatic surgery and laparoscopy will be able to establish its role and its hypothetical advantages MethodsOut of 138 pancreatic surgeries performed in a two-year period (2017-2019), 23 were laparoscopic PD. We evaluate its efficacy and safety compared to 31 open PD. ResultsThere were no cases of B/C pancreatic or biliary fistula, nor any cases of delayed gastric emptying in the laparoscopic group, but hemorrhage required one reoperation. The conversion rate was 21% (five cases): one due to bleeding, and the remainder for non-progression. The converted patients showed no differences compared to those completed by laparoscopy. There were no differences between laparoscopic and open PD in surgical time, postoperative complications, reintervention rate, readmissions or mortality. R0 resection in tumor cases was 85% for laparoscopy and 69% in open surgery without statistical significance. The postoperative hospital stay was shorter in the laparoscopic PD group (eight vs. 15 days). ConclusionsIn a selected group, laparoscopic PD can be safely and effectively performed if carried out by groups who are experts in pancreatic surgery and advanced laparoscopy. The technique has the same postoperative results as open surgery and is oncologically adequate, with less hospital stay. Proper patient selection, a step-by-step program and a lax and early conversion prevents serious operating accidents.

Custom made total knee arthroplasty : Review of current literature

Custom-designed total knee replacement has become astandard procedure in some orthopaedic centres worldwide. Due to the lack of literature, the discussion about the hypothetical advantages has remained controversial. It was the aim of this study to focus on the current literature on custom-made total knee arthroplasty. We can demonstrate that custom-made total knee arthroplasty is areproducible strategy with good clinical results in terms of leg-axis reconstruction, natural kinematics, patient-related outcomes and cost effectiveness. This has led to the fact that the Orthopaedic Data Evaluation Panel (ODEP) of the National Health Service in Great Britain rated the Conformis custom-designed knee replacement in 2017 with a3D rating.

M44 - PATIENT OUTCOMES OF PSYCHIATRIC GENETIC COUNSELING: ASSESSING THE IMPACT OF DIFFERENT FAMILY HISTORY COLLECTION MODALITIES

Background Though often thought of as an intervention exclusively concerned with delivering information about genetic testing/recurrence risk, Genetic Counseling (GC) is actually “a process of helping people to understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease.” Documentation of family history (Fhx) is fundamental to this process for GC; it provides a basis for genetic risk assessment, and for personalizing conversations about illness etiology. The process of Fhx documentation can also build rapport, which is key to optimal patient outcomes of GC. Various approaches for obtaining the Fhx have been employed, often motivated by a desire to increase the efficiency of generating an accurate pedigree. However, no studies have evaluated whether different modalities for collection of Fhx data influence patient outcomes. Pre-appointment phone calls have the theoretical advantages of helping to clarify expectations and initiate rapport-building prior to the appointment, and allowing the patient and counselor to more fully attend to the content of the GC session if Fhx has been documented in advance. Methods We sought to test the hypothesis that patient outcomes of psychiatric GC would demonstrate more dramatic improvements when Fhx was collected via telephone prior to their appointment (FhxPrior) as compared to when Fhx was collected during the appointment (FhxDuring). We used data from our specialist psychiatric GC clinic, where as routine clinical practice, patients complete the GC outcomes scale (GCOS, measuring empowerment) and Illness Management Self Efficacy Scale (IMSES) immediately prior to GC (T1) and at one-month follow-up (T2). Because of the hypothetical advantages of collecting Fhx before the appointment, this is standard practice for the clinic. However, when a patient cannot be reached by telephone before the appointment, Fhx is collected during the appointment. Study inclusion criteria required: 1) that both T1 and T2 assessments were completed between 1 Feb 2012 - 31 Jan 2017, 2) that the Fhx was obtained from the patient him/herself, and 3) that the psychiatric GC appointment was conducted in person (rather than by telephone or videoconference). Change in scale scores between T1 and T2 were compared between groups using Mann-Whitney U tests. Results Of 573 patients who had completed T1 questionnaires, 240 met inclusion criteria and were included in the analysis (FhxPrior, n=206; FhxDuring, n=34). Overall, patient GCOS and IMSES scores increased significantly from T1-T2 (p=0.000, d=1.2 and p=0.004, d=0.24 respectively). The increase in IMSES scores from T1-T2 was significantly greater for the FhxPrior group than for the FhxDuring group (p=0.014, d=0.64). There was no difference in the increase in GCOS score between groups (p=0.649). Discussion Our data support previous findings regarding the important positive outcomes of psychiatric GC for patients, and suggest that obtaining Fhx via telephone prior to a psychiatric GC appointment may lead to greater increases in patient self-efficacy as compared to obtaining Fhx during the GC appointment. Future research will include prospective evaluation of alternate Fhx collection methods to maximize patient outcomes in our clinic.

Vulture litigation in the context of sovereign debt: global or local solutions?

The idea of “anti-vulture legislation”, i.e. domestic law dealing with holdout strategies and “vulture” litigation against a sovereign debtor in financial distress, differs radically from existing and proposed approaches to deal with sovereign debt crises, such as the contractual approach and the proposal for an international sovereign debt restructuring mechanism. Anti-vulture laws adopted in Belgium, in the United Kingdom and, more recently, in France offer an ambitious local solution to a global problem. Motivated by these developments, we investigate the actual or hypothetical advantages attached to anti-vulture legislation compared to other approaches, and we argue that legislative interventions in sovereign debt-enforcement regimes should be made cautiously with the aim of promoting timely, orderly and equitable solutions to sovereign debt crises.

The use of robotic surgery in abdominal organ transplantation: A literature review.

Minimally invasive surgical approaches in transplantation are gaining increasing interest, and many centers are reporting their, mainly laparoscopic, experiences. Robotic surgery (RS) has some hypothetical advantages over traditional laparoscopy and has been successfully applied, although infrequently to organ transplantation. Our goal was to review and critique the publications reporting RS use in organ transplantation. Most of the RS experience has been with living renal donor organ procurement and, to a lesser extent, with RS procedures in the transplant recipient. The available literature suggests that RS appears to be a safe surgical alternative to standard open procedures. RS in living liver donor surgery remains limited, and more experience is required before commenting on RS-related outcomes RS in pancreatic transplantation is exceedingly rare. The enhanced precision and ergonomics of RS may expand its applicability to liver living donation and pancreas transplantation at some point in the future.

A Critical Evaluation of Bail-Ins as Bank Recapitalisation Mechanisms

Many of the world’s developed economies have introduced, or are planning to introduce, bank bail-in regimes. Both the planned EU resolution regime and the European Stability Mechanism Treaty involve the participation of bank creditors in bearing the costs of bank recapitalization via the bail-in process as one of the (main) mechanisms for restoring a failing bank to health. There is a long list of actual or hypothetical advantages attached to bail-in centred bank recapitalizations. Most importantly the bail-in tool involves replacing the implicit public guarantee, on which fractional reserve banking has operated, with a system of private penalties. The bail-in tool may, indeed, be much superior in the case of idiosyncratic failure. Nonetheless, there is need for a closer examination of the bail-in process, if it is to become a successful substitute to the unpopular bailout approach. This paper discusses some of its key potential shortcomings. It explains why bail-in regimes will fail to eradicate the need for an injection of public funds where there is a threat of systemic collapse, because a number of banks have simultaneously entered into difficulties, or in the event of the failure of a large complex cross-border bank, except in those cases where failure was clearly idiosyncratic.

Critical Reflections on Bank Bail-ins

Many of the world’s developed economies have introduced, or are planning to introduce, bank bail-in regimes that involve the participation of bank creditors in bearing the costs of restoring a failing bank to health. There is a long list of actual or hypothetical advantages attached to the bail-in process. Therefore, there is a need for a closer examination of the bail-in process, if it is to become a successful substitute to the unpopular bailout approach. The bail-in tool involves replacing the implicit public guarantee, on which fractional reserve banking has operated, with a system of private penalties. The bail-in approach may, indeed, be much superior to bailouts in the case of idiosyncratic failure. In other cases, the bail-in process may entail important risks. The article provides a legal and economic analysis of some of the key potential risks bail-ins may entail both in the domestic and cross-border contexts. It explains why bail-in regimes will not eradicate the need for injection of public funds where there is a threat of systemic collapse, because a number of banks have simultaneously entered into difficulties, or in the event of the failure of a large complex cross-border bank, unless the failure was clearly idiosyncratic.

Uniparental inheritance of organelle genes

Uniparental inheritance of organelle genes

Airway pressure release ventilation: A pediatric case series

Airway pressure release ventilation (APRV) is a relatively new mode of mechanical ventilation (MV) first described in animal studies in 1987 and in humans in 1988. It is a time-triggered, time-cycled, pressure-limited mode where a high level of continuous positive airway pressure (CPAP) is maintained with brief regular releases in pressure, and spontaneous breathing is allowed throughout the cycle. In theory, it is consistent with a lung protective approach while having some hypothetical advantages over HFOV. The use of this mode of ventilation in pediatrics has been limited. The authors describe their experience with this mode of ventilation in a series of pediatric patients.

Functional outcome after trypan blue–assisted vitrectomy for macular pucker: a prospective, randomized, comparative trial

Purpose To evaluate funtional oucome after the intraoperative application of 0.06% trypan blue during vitrectomy for macular pucker. Design Prospective, randomized, comparative study. Methods Forty-three eyes of 43 consecutive patients, 30 women and 13 men, were incorporated in the study. Patients were randomized into two groups: group 1 (n = 22) with trypan blue (0.06%) staining, and group 2 (n = 21) without trypan blue staining. Functional outcome (best-corrected visual acuity, Goldmann perimetry) was evaluated 1 day before surgery, at 6 weeks, and at intervals of 3, 6, and 12 or more months postoperatively. Only patients with an idiopathic macular pucker were included. In all patients, a standard three-port pars plana vitrectomy with peeling of an epiretinal membrane (ERM) and the internal limiting membrane was performed. No other modification of the surgical procedure, except the use of trypan blue was made between the two groups. Results Mean age was 68.9 years in group 1 (with trypan blue) and 69.4 in group 2 (without trypan blue). Median best-corrected visual acuity was 20/63 in both groups (range, 20/200–20/40; P > .5) before surgery. Mean follow-up time was 5.8 months in group 1 and 5.3 months in group 2. After surgery, median visual acuity had increased to 20/40 in both groups (range, 20/500 to 20/20 in group 1 and 20/100 to 20/20 in group 2; P < .001 for both groups). The difference between both groups was not statistically significant ( P > .5). An improvement of visual acuity (gain of 2 or more lines) was seen in 16 patients of both groups. No postoperative visual field defects were noted. Conclusions Trypan blue–assisted vitrectomy for macular pucker leads to good functional results with no dye-related adverse effects after short follow-up. Trypan blue might be especially applicable in cases in which the borders of the ERM are difficult to define. Hypothetical advantages, such as fewer recurrences of ERMs after trypan blue staining, will have to be evaluated during further follow-up of patients.

Non-interference between two protein carriers when used with the same polysaccharide for pneumococcal conjugate vaccines in 2-year-old children

The carriers tetanus toxoid (T) and diphtheria CRM-197 (C) were compared in conjugate vaccines using identical coupling chemistry and polysaccharide (PS) loading, for safety and immunogenicity in 2-year-old children. Also tested were a mixture of halved doses of both carriers bearing the same PS serotypes. For this study, PS types 6A, 14, 19F, and 23F (separately) were coupled to T or C by reductive amination at PS/protein ratios of 0.50±0.18. With each carrier the four PS types were combined, giving the tetravalent vaccines “T-6, -14, -19, -23” or “C-6, -14, -19, -23” containing 50 μg of the carrier and roughly 20 μg total PS per ml of saline (no adjuvant). The children received primary (1′) injections of 50 μg (protein) of either vaccine or a mixture of 25 μg of both; identical secondary (2′) injections were given 2 months afterwards. Sera were taken before the 1′ and 2′ and 1 month post-2′, and serum IgG responses to the four PS were determined by ELISA. For geometric mean (GM) post-1′ antibody, “C-6, -14, -19, -23” exceeded “T-6, -14, -19, -23” for type 19F; for 2′ antibody, “T-6, -14, -19, -23” exceeded “C-6, -14, -19, -23” for type 14, but “C-6, -14, -19, -23” and the T/C mixture exceeded “T-6, -14, -19, -23” for the type 23F response. No other differences were significant. Analyzed by individual fold-rises, “C-6, -14, -19, -23” and the T/C mixture exceeded “T-6, -14, -19, -23” for types 19F and 23F. Thus, there was no consistent difference between the T and C carriers; rather, the results differed by serotype. When a mixture of halved doses of “T-6, -14, -19, -23” and “C-6, -14, -19, -23” was injected, neither negative nor positive interference with the PS antibody responses was found. Anticipating multivalent PS conjugate vaccines of the future to be used in infancy, this strategy would have two hypothetical advantages worth further investigation—avoiding “carrier epitopic overload” by reducing each carrier dosage and recruiting T-helper activity by both carriers for each PS.

Does community-based experience alter career preference? New evidence from a prospective longitudinal cohort study of undergraduate medical students.

Previous studies have shown that most medical students want a hospital-based career, but the protagonists of community-based teaching predict that increased community exposure within undergraduate curricula will alter subsequent career preferences. To evaluate the impact on career preference and other attitudes of a year with substantial community exposure, compared with a year of hospital-based learning. Questionnaire to student cohort before and after two consecutive levels of the course, one with, and the other prior to, substantial community placement. Sheffield Medical School. Total of 260 students in the third and fourth year of the MBChB degree. There were significant differences in career preference and attitude to primary care after the year with a community placement, with more students expressing a preference for a community-based career. This was particularly true for women, and less true for non-European students. Conversely, the hospital-based students, especially men, showed a significant change toward hospital-based careers. The findings support the hypothetical advantages of shifting medical education to primary care settings, both in encouraging a career in general practice and in the retention of appropriate professional attitudes.

Motor response of the leg muscles produced by position-selective stimulation of spinal nerve roots.

To define and measure motor responses of the leg muscles in the ankle associated with position-selective and tetanic stimulation of spinal nerve roots L3-S1. Sixteen lumbosacral spinal nerve roots in 14 subjects were stimulated intraoperatively after surgical exposure and decompression for a herniated disc. Each contact of a spiral cuff multielectrode was wrapped around the root and used to excite a spatially defined population of axons beneath the electrode. The motor response from each stimulated position was evaluated in terms of three-dimensional vector torque in the ankle. Each position at which the stimulating electrode was placed around the root exhibited the same vector torque qualitatively, but at different thresholds. The root was most excitable ventrally. The S1 roots responded with a uniform three-dimensional torque pattern: plantar flexion plus lateral leg and foot rotation plus inversion. All L5 roots responded by plantar flexion. Dorsiflexion torque was possible only with stimulation of the L3 and L4 roots. Eversion was not possible with stimulation of the S1 roots or with most of the L5 roots. Position-selective stimulation of the extrathecal spinal nerve roots influences the threshold of the biomechanical response, the torque recruitment dynamics, and the magnitude of three-dimensional vector torque. Selective activation of some leg muscles or agonist muscle groups with stimulation of a single nerve root could not be achieved owing to the low spatial selectivity of the stimulation design and/or the low muscle specificity of motor fascicles in the root. Direct extrathecal stimulation of spinal nerve roots has some hypothetical advantages over stimulation of other sites along the peripheral nerves, owing to their unique anatomy, and may contribute to functional electrical stimulation of the lower extremities. Further investigation with a more selective multielectrode configuration and the use of multiple root stimulation is suggested.