Research design considerations for randomized controlled trials of spinal cord stimulation for pain: Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials/Institute of Neuromodulation/International Neuromodulation Society recommendations

ABSTRACT

Spinal cord stimulation (SCS) is an interventional nonpharmacologic treatment used for chronic pain and other indications. Methods for evaluating the safety and efficacy of SCS have evolved from uncontrolled and retrospective studies to prospective randomized controlled trials (RCTs). Although randomization overcomes certain types of bias, additional challenges to the validity of RCTs of SCS include blinding, choice of control groups, nonspecific effects of treatment variables (eg, paresthesia, device programming and recharging, psychological support, and rehabilitative techniques), and safety considerations. To address these challenges, 3 professional societies (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials, Institute of Neuromodulation, and International Neuromodulation Society) convened a meeting to develop consensus recommendations on the design, conduct, analysis, and interpretation of RCTs of SCS for chronic pain. This article summarizes the results of this meeting. Highlights of our recommendations include disclosing all funding source and potential conflicts; incorporating mechanistic objectives when possible; avoiding noninferiority designs without internal demonstration of assay sensitivity; achieving and documenting double-blinding whenever possible; documenting investigator and site experience; keeping all information provided to patients balanced with respect to expectation of benefit; disclosing all information provided to patients, including verbal scripts; using placebo/sham controls when possible; capturing a complete set of outcome assessments; accounting for ancillary pharmacologic and nonpharmacologic treatments in a clear manner; providing a complete description of intended and actual programming interactions; making a prospective ascertainment of SCS-specific safety outcomes; training patients and researchers on appropriate expectations, outcome assessments, and other key aspects of study performance; and providing transparent and complete reporting of results according to applicable reporting guidelines.

Persistent Spinal Pain Syndrome: A Proposal for Failed Back Surgery Syndrome and ICD-11

Objective

For many medical professionals dealing with patients with persistent pain following spine surgery, the term Failed back surgery syndrome (FBSS) as a diagnostic label is inadequate, misleading, and potentially troublesome. It misrepresents causation. Alternative terms have been suggested, but none has replaced FBSS. The International Association for the Study of Pain (IASP) published a revised classification of chronic pain, as part of the new International Classification of Diseases (ICD-11), which has been accepted by the World Health Organization (WHO). This includes the term Chronic pain after spinal surgery (CPSS), which is suggested as a replacement for FBSS.

Methods

This article provides arguments and rationale for a replacement definition. In order to propose a broadly applicable yet more precise and clinically informative term, an international group of experts was established.

Results

14 candidate replacement terms were considered and ranked. The application of agreed criteria reduced this to a shortlist of four. A preferred option—Persistent spinal pain syndrome—was selected by a structured workshop and Delphi process. We provide rationale for using Persistent spinal pain syndrome and a schema for its incorporation into ICD-11. We propose the adoption of this term would strengthen the new ICD-11 classification.

Conclusions

This project is important to those in the fields of pain management, spine surgery, and neuromodulation, as well as patients labeled with FBSS. Through a shift in perspective, it could facilitate the application of the new ICD-11 classification and allow clearer discussion among medical professionals, industry, funding organizations, academia, and the legal profession.

The beta-adrenergic receptor agonist, terbutaline, reduces UVB-induced mechanical sensitization in humans

OBJECTIVES

Previously, we found in cultures of primary neurons and in animals that sensitized primary neurons can be desensitized by treatment with e.g. beta-adrenergic receptor agonists. We now tested whether also in human sensitization such as UVB-radiation induced sunburn-like hyperalgesia can be reduced by intradermal injection of the beta-adrenergic receptor agonist terbutaline.

METHODS

In our prospective randomized study, 17 participants received an individual UVB dose to cause a defined local sunburn-like erythema at four locations, two on each forearm. Twenty-four hours later, the sensitized four areas were injected intradermally with terbutaline pH 4.3, terbutaline pH 7.0, saline pH 4.3 or saline pH 7.0, respectively. Pain thresholds were examined before and after induction of UVB-sensitization, and 15, 30 and 60 min after injection of the respective solution. Mechanical pain thresholds of the skin and of deeper tissues were determined by pinprick and pressure algometer measurements, respectively.

RESULTS

UVB-irradiation decreased mechanical pain thresholds for pinprick and pressure algometer measurements demonstrating a successful sunburn-like sensitization. Intradermal injection of terbutaline pH 7.0 into the sensitized skin reduced the sensitization for all measured timepoints as determined by pinprick measurements. Pinprick measurements of sensitization were not reduced by injection of terbutaline pH 4.3, saline solution pH 7.0 or saline solution pH 4.3. Also, sensitization of deeper tissue nociceptors were not altered by any of the injections as measured with the pressure algometer.

CONCLUSIONS

Similar to our cellular observations, also in humans beta-adrenergic agonists such as terbutaline can reduce the sensitization of primary neurons in the skin.

SIGNIFICANCE

We previously showed in model systems that beta-adrenergic stimulation can not only sensitize but also desensitize nociceptors. Our study shows that also in humans beta-adrenergic agonists desensitize if injected into UVB-sensitized skin. This indicates an analgesic activity of adrenergic agonists in addition to their vasoconstrictory function.

Report of the NIH Task Force on Research Standards for Chronic Low Back Pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific, and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. The NIH Pain Consortium therefore charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimal data set to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect the RTF recommendations will become a dynamic document, and undergo continual improvement.

PERSPECTIVE

A Task Force was convened by the NIH Pain Consortium, with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimal dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Report of the NIH Task Force on research standards for chronic low back pain

OBJECTIVE

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific, and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus.

DESIGN

Expert panel and preliminary evaluation of key recommendations.

METHODS

The NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel developed a 3-stage process, each with a 2-day meeting.

RESULTS

The panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimal data set to describe research subjects (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals.

CONCLUSION

The RTF believes these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes. We expect the RTF recommendations will become a dynamic document, and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Report of the NIH Task Force on research standards for chronic low back pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. Therefore, NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimum dataset to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect that the RTF recommendations will become a dynamic document and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

Report of the National Institutes of Health task force on research standards for chronic low back pain

OBJECTIVES

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed nonspecific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. The purpose of this article is to disseminate the report of the National Institutes of Health (NIH) task force on research standards for cLBP.

METHODS

The NIH Pain Consortium charged a research task force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel developed a 3-stage process, each with a 2-day meeting.

RESULTS

The panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimal data set to describe research subjects (drawing heavily on the Patient Reported Outcomes Measurement Information System methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved these recommendations, which investigators should incorporate into NIH grant proposals.

CONCLUSIONS

The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of cLBP. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes. We expect the RTF recommendations will become a dynamic document and undergo continual improvement.

Report of the NIH Task Force on research standards for chronic low back pain

Despite rapidly increasing intervention, functional disability due to chronic low back pain (cLBP) has increased in recent decades. We often cannot identify mechanisms to explain the major negative impact cLBP has on patients' lives. Such cLBP is often termed non-specific and may be due to multiple biologic and behavioral etiologies. Researchers use varied inclusion criteria, definitions, baseline assessments, and outcome measures, which impede comparisons and consensus. Therefore, NIH Pain Consortium charged a Research Task Force (RTF) to draft standards for research on cLBP. The resulting multidisciplinary panel recommended using 2 questions to define cLBP; classifying cLBP by its impact (defined by pain intensity, pain interference, and physical function); use of a minimum dataset to describe research participants (drawing heavily on the PROMIS methodology); reporting "responder analyses" in addition to mean outcome scores; and suggestions for future research and dissemination. The Pain Consortium has approved the recommendations, which investigators should incorporate into NIH grant proposals. The RTF believes that these recommendations will advance the field, help to resolve controversies, and facilitate future research addressing the genomic, neurologic, and other mechanistic substrates of chronic low back pain. We expect that the RTF recommendations will become a dynamic document and undergo continual improvement.

PERSPECTIVE

A task force was convened by the NIH Pain Consortium with the goal of developing research standards for chronic low back pain. The results included recommendations for definitions, a minimum dataset, reporting outcomes, and future research. Greater consistency in reporting should facilitate comparisons among studies and the development of phenotypes.

[Chili for therapy of trigeminus neuralgia: a case report]

We report the case of a 39-year-old female patient who suffered from trigeminal neuralgia of the left lingual nerve for 6 years. The previous therapy according to the guidelines including a Jannetta operation was unsuccessful. Only after beginning with daily mastication and consumption of very hot chilli peppers has the patient become reliably pain-free.

Anatomy of the spinal cord in patients with meningomyelocele with and without hypoplasia or hydromyelia

We compared the cross-sectional areas of spinal cords of patients with normal cords to the area of patients with meningomyelocele. The control group consisted of examinations of 27 patients with normal spinal cords providing 1547 axial images at 20 levels, C2-L2. The meningomyelocele group consisted of 67 MRI examinations of 41 patients, providing 4,095 axial images at 23 levels C2 to S1. Thirty-four examinations were of 21 patients with minimal hydromyelia, 7 examinations were of 3 patients with operable hydromyelia, and 26 examinations were of 17 patients without hydromyelia. In an additional analysis, we selected those meningomyelocele patients with cord tethering but without hydromyelia or hypoplasia (53 examinations of 30 patients) and compared them to symptomatic hypoplasia cases (9 examinations of 6 patients). The symptomatic hypoplasia cases were chosen because of progressive loss of muscle strength and worsening spasticity not relieved by surgical adhesiolysis. The test, retest error was 5.6% with differences between the means of repeated readings not being significant. All tests for significance were paired T test. The areas of spine levels C7-L2 for the controls were significantly larger than for the meningomyelocele patients (p = 0.000007). Including all levels C2-S1, the minimal hydromyelia cases were not significantly different from those without hydromyelia (p = 0.5). The areas C2-S1 of operable hydromyelia cases were larger than both non-shunted minimal hydromyelia (p = 0.00009) and of meningomyelocele patients without hydromyelia (p = 0.00003). The areas C7-L2, of hypoplasia cases were significantly smaller compared to the "normal" meningomyelocele cases (p = 0.0004). These data suggest that hydromyelia stimulates overgrowth of the cord, as does hydrocephalus of the brain, and that adhesiolysis procedures are of no value with hypoplasia of the spinal cord.

Epidemiology of tethered cord with meningomyelocele

This paper describes the epidemiology of tethered cord syndrome and its etiologies and co-morbidities following initial repair of both meningomyeloceles and lipomeningomyelocele. A review of the pertinent literature and data from 654 cases of meningomyelocele and 118 cases of lipomeningomyelocele has been drawn from a computerized database, Patient Data Management System/fx. Only cases born since 1964 were analyzed for the etiologies, co-morbidities, spinal cord abnormalities detected by contrast studies or MRI and for significant symptoms and signs. Tethered cord symptoms were related to an attachment to a rigid tether for all 31 cases following lipomeningomyelocele repair but 62 (75%) of the 83 post meningomyelocele repair patients developed the symptoms of tethered cord. Causes other than, or in addition to, tethering included an obstructed cerebrospinal fluid shunt, syringohydromyelia, benign tumor and spinal cord hypoplasia. Quantitative differentiation between asymptomatic thin spinal cords and symptomatic spinal cord hypoplasia as well as between central canal enlargement and symptomatic syringohydromyelia could not be demonstrated. Collaborative, multi-center studies of larger numbers of patients are recommended.

Clinical clerkships in neurosurgery and neurology at United States medical schools

The neurology and neurosurgery clinical clerkship experience (excluding lectures and conferences) of the students in U.S. allopathic medical schools during one of the academic years 1986 to 1987 or 1987 to 1988 was surveyed. Almost all schools have at least some students taking these clerkships. The majority of students (78%) have clinical exposure to neurology, but only a minority (28%) take a neurosurgical clerkship; however, far more schools require their students to take neurology clerkships (54%) than neurosurgical clerkships (12%). A few require that either be taken. Overall, 81% of schools require all students to take at least one of these clerkships. For the most part, students taking a clerkship in either specialty do not do so again. The initial and usually unique exposure averages 3.5 weeks in neurology and 2.4 weeks in neurosurgery. For each specialty, required clerkships tended to be shorter than selective clerkships, which in turn were shorter than elective ones. Furthermore, first clerkships offered in the fourth year, whether they were required, selective, or elective, tended to be longer than the corresponding third-year first clerkships at other schools. Whereas the average length of a first clinical clerkship in neurology is almost as long for schools requiring it (3.4 wk) as for those that offer it as an elective or selective (4.0 wk), required neurosurgical clerkships are much shorter (1.5 wk) than elective or selective rotations (3.1 wk). Schools with residency training programs more frequently required students to a clerkship and, consequently, had greater numbers of students taking a clerkship in the corresponding specialty.(ABSTRACT TRUNCATED AT 250 WORDS)

Barbiturate-augmented hypothermia for reduction of persistent intracranial hypertension

✓ Thiopental and pentobarbital caused further reductions in intracranial pressure (ICP) in five patients with persistent intracranial hypertension who had been previously treated with diuretics, steroids, and hyperventilation therapy. The ICP reduction obtained with these patients at normothermia was rapid. Abrupt increases in ICP could be quickly checked by barbiturate treatment. Frequently, the ICP reduction was accompanied by an improvement in the cerebral perfusion pressure. Reduction of ICP by thiopental was brief while that due to pentobarbital was more prolonged. Sustained intracranial pressure reduction could be maintained for up to 5 days by combining pentobarbital (serum concentration 3 mg%) and hypothermia (30°C) without cardiovascular instability or other untoward side-effects. The cerebral metabolic depression due to this combined therapy may be additive and therefore offer a greater protection to the brain during periods of elevated ICP.