Benjamin C. Lopez

Bio: Benjamin C. Lopez is an academic researcher from Queen Mary University of London. The author has contributed to research in topics: Trigeminal neuralgia & Microvascular decompression. The author has an hindex of 6, co-authored 10 publications receiving 1053 citations.

Wall and Melzack's textbook of pain

Abstract: WALL AND MELZACK'S TEXTBOOK OF PAIN, revised under new editorial leadership, and with a host of new, multidisciplinary international contributors ...

Systematic review of ablative neurosurgical techniques for the treatment of trigeminal neuralgia.

Abstract: There are no randomized controlled trials comparing retrogasserian percutaneous radiofrequency thermocoagulation, glycerol rhizolysis, balloon compression of the gasserian ganglion, and stereotactic radiosurgery, nor are there systematic reviews using predefined quality criteria. The objective of this study was to systematically identify all of the studies reporting outcomes and complications of ablative techniques for treatment of trigeminal neuralgia, from the development of electronic databases, and to evaluate them with predefined quality criteria.Methods: Inclusion criteria for the outcome analysis included thorough demographic documentation, defined diagnostic and outcome criteria, a minimum of 30 patients treated and median/mean follow-up times of 12 months, not more than 20% of patients lost to follow-up monitoring, Kaplan-Meier actuarial analysis of individual procedures, less than 10% of patients retreated because of failure or early recurrence, and a minimal dose of 70 Gy for stereotactic radiosurgery. High quality studies with no actuarial analysis were used for the evaluation of complications.Results: Of 175 studies identified, 9 could be used to evaluate rates of complete pain relief on a yearly basis and 22 could be used to evaluate complications. In mixed series, radiofrequency thermocoagulation offered higher rates of complete pain relief, compared with glycerol rhizolysis and stereotactic radiosurgery, although it demonstrated the greatest number of complications.Conclusion: Radiofrequency thermocoagulation offers the highest rates of complete pain relief, although further data on balloon microcompression are required. It is essential that uniform outcome measures and actuarial methods be universally adopted for the reporting of surgical results. Randomized controlled trials are required to reliably evaluate new surgical techniques.

Patient Reports of Satisfaction after Microvascular Decompression and Partial Sensory Rhizotomy for Trigeminal Neuralgia

Abstract: OBJECTIVE: There are no reports of patient satisfaction surveys after either a microvascular decompression (MVD) or a partial sensory rhizotomy (PSR) for trigeminal neuralgia. This study compares patient satisfaction after these two types of posterior fossa surgery for trigeminal neuralgia, because it is postulated that recurrences, complications, and previous surgical experience reduce satisfaction.METHODS: All patients who had undergone their first posterior fossa surgery at one center were sent a self-complete questionnaire by an independent physician. Among the 44 questions on four standardized questionnaires were 5 questions that related to patient satisfaction and experience of obtaining care. Patients were divided into those having their first surgical procedure (primary) and those who had had previous ablative surgery (nonprimary).RESULTS: Response rates were 90% (220 of 245) of MVD and 88% (53 of 60) of PSR patients. Groups were comparable with respect to age, sex, duration of symptoms, mean duration of follow-up, and recurrence rates. Overall satisfaction with their current situation was 89% in MVD and 72% in PSR patients. Unsatisfied with the outcome were 4% of MVD and 20% of PSR patients, and this is a significant difference (P < 0.01). Satisfaction with outcome was higher in those undergoing this as a primary procedure. In the primary group, satisfaction was dependent on recurrence and complication/side effects status (each P < 0.01), but this was not the case in the nonprimary group. Patients expressed a desire for earlier posterior fossa surgery in 73% of MVD and 58% of PSR patients, and this was highest in the primary group. The final outcome was considered to be better than expected in 80% of MVD and 54% of PSR patients, but 22% of the PSR group (P < 0.01) thought they were worse off.CONCLUSION: Patients undergoing posterior fossa surgery as a primary procedure are most satisfied and PSR patients are least satisfied, partly because of a higher rate of Side effects.

Quality of reporting in evaluations of surgical treatment of trigeminal neuralgia: recommendations for future reports

Abstract: OBJECTIVE: There are numerous reports on the surgical treatment of trigeminal neuralgia, but the-studies do not Use, uniform outcome measures, which makes it difficult for patients and,clinicians to determine which treatment may be most appropriate. The objectives of this study were to set quality criteria and standards for outcome reporting for the surgical treatment of trigeminal neuralgia (on the basis of international expert opinion), to identify and assess all studies of the surgical treatment of trigeminal neuralgia and evaluate the studies against those criteria, and to provide recommendations for submitting reports on the outcome of surgical treatment of trigeminal neuralgia.METHODS: The types of data 11 neurosurgeons and 2 neurologists considered essential for articles reporting the outcomes of surgical treatment of trigeminal neuralgia were the quality criteria used by the two authors. Standards were establised in terms of the minimal number and type of criteria that studies should meet to allow their use in a potential systmatic review of pain outcomes of surgical treatment of trigeminal neuralgia. Studies were identified in MEDLINE searches and from other sources and were independently scored against those criteria by the two authors. The reproducibility of the method was checked with assessments of inter- and intra-rater reliability. A checklist for the reporting of studies was formulated.RESULTS: A total of 281 studies were identified, of which 222 were scored. Seventy-one (32%) of the studies reached the minimal set standards, but only 28 (13%) could be used for assessment of pain outcomes, because they included actuarial analyses. There was a good agreement between the two authors in the scoring of the studies, although some criteria required stricter definitions. A checklist for the reporting of future studies on the surgical treatment of trigeminal neuralgia was proposed.CONCLUSION: When assessed against the proposed criteria and standards, the quality of reporting was generally poor. The methods for reporting surgical outcomes for trigeminal neuralgia were not uniform; therefore, the comparability of results and techniques was low. Data should be collected and reported in a standardized way. A protocol for data collection and reporting on the surgical treatment of trigeminal neuralgia has been proposed. Further research is needed to evaluate this tool.

Patient satisfaction after surgery for trigeminal neuralgia--development of a questionnaire.

Abstract: Objective. This project aimed to prepare a self complete patient satisfaction survey for patients who have undergone surgery for trigeminal neuralgia and then assess its reproducibility, validity and acceptability in one centre.

Neuropathic pain Redefinition and a grading system for clinical and research purposes

Abstract: Pain usually results from activation of nociceptive afferents by actually or potentially tissue-damaging stimuli. Pain may also arise by activity generated within the nervous system without adequate stimulation of its peripheral sensory endings. For this type of pain, the International Association for the Study of Pain introduced the term neuropathic pain, defined as "pain initiated or caused by a primary lesion or dysfunction in the nervous system." While this definition has been useful in distinguishing some characteristics of neuropathic and nociceptive types of pain, it lacks defined boundaries. Since the sensitivity of the nociceptive system is modulated by its adequate activation (e.g., by central sensitization), it has been difficult to distinguish neuropathic dysfunction from physiologic neuroplasticity. We present a more precise definition developed by a group of experts from the neurologic and pain community: pain arising as a direct consequence of a lesion or disease affecting the somatosensory system. This revised definition fits into the nosology of neurologic disorders. The reference to the somatosensory system was derived from a wide range of neuropathic pain conditions ranging from painful neuropathy to central poststroke pain. Because of the lack of a specific diagnostic tool for neuropathic pain, a grading system of definite, probable, and possible neuropathic pain is proposed. The grade possible can only be regarded as a working hypothesis, which does not exclude but does not diagnose neuropathic pain. The grades probable and definite require confirmatory evidence from a neurologic examination. This grading system is proposed for clinical and research purposes.

Fmri-based neurologic signature of physical pain

Abstract: Described herein is a novel fMRI-based neurologic signature that predicts pain. Further described are methods for detecting pain, for diagnosing pain-related neuropathic conditions and for predicting or evaluating efficacy of an analgesic based on the neurologic signature.

A catalogue of reporting guidelines for health research.

Abstract: Growing evidence demonstrates widespread deficiencies in the reporting of health research studies. The EQUATOR Network is an international initiative that aims to enhance the reliability and value of the published health research literature. EQUATOR provides resources, education and training to facilitate good research reporting and assists in the development, dissemination and implementation of robust reporting guidelines. This paper presents a collection of tools and guidelines available on the EQUATOR website (http://www.equator-network.org) that have been developed to increase the accuracy and transparency of health research reporting.

The neurobiology of itch

Abstract: Itch and pain are distinct sensations processed by different but overlapping neural pathways. Ikomaet al. review recent evidence on the molecular mechanisms that underlie itch sensation, highlighting the complex interaction with pain processing, and discuss the therapeutic implications. The neurobiology of itch, which is formally known as pruritus, and its interaction with pain have been illustrated by the complexity of specific mediators, itch-related neuronal pathways and the central processing of itch. Scratch-induced pain can abolish itch, and analgesic opioids can generate itch, which indicates an antagonistic interaction. However, recent data suggest that there is a broad overlap between pain- and itch-related peripheral mediators and/or receptors, and there are astonishingly similar mechanisms of neuronal sensitization in the PNS and the CNS. The antagonistic interaction between pain and itch is already exploited in pruritus therapy, and current research concentrates on the identification of common targets for future analgesic and antipruritic therapy.