Innovations and advances in modelling and measuring pain in animals.

Best practices in preclinical algesiometry (pain behaviour testing) have shifted over the past decade as a result of technological advancements, the continued dearth of translational progress and the emphasis that funding institutions and journals have placed on rigour and reproducibility. Here we describe the changing trends in research methods by analysing the methods reported in preclinical pain publications from the past 40 years, with a focus on the last 5 years. We also discuss how the status quo may be hampering translational success. This discussion is centred on four fundamental decisions that apply to every pain behaviour experiment: choice of subject (model organism), choice of assay (pain-inducing injury), laboratory environment and choice of outcome measures. Finally, we discuss how human tissues, which are increasingly accessible, can be used to validate the translatability of targets and mechanisms identified in animal pain models.

Comparison of Prognostic Scoring Systems to Predict Durable Pain Relief After Microvascular Decompression for Trigeminal Neuralgia.

BACKGROUND: Microvascular decompression (MVD) is an effective treatment for trigeminal neuralgia, but pain recurs in a substantial minority of patients. Two recently published scoring systems by Hardaway et al. and Panczykowski et al. use simple preoperative clinical and imaging features to predict durable pain relief following MVD, but their predictive performance has not been independently validated. This study aimed to compare predictive performance of the Hardaway et al. score (HS) and Panczykowski et al. score (PS) for 1-year, 3-year, and long-term pain-free outcomes after MVD for trigeminal neuralgia. METHODS: HS and PS were computed for a retrospective, single-institution cohort of 68 patients with trigeminal neuralgia who underwent MVD. Primary outcome was pain recurrence after MVD. Predictive performance of HSs and PSs was evaluated with area under the curve sensitivity analysis and regression models for survival analyses at 1 year, 3 years, and last follow-up. RESULTS: Area under the curve for predicting pain-free outcome was higher for PS versus HS at 1 year (0.873 vs. 0.775) and 3 years (0.793 vs. 0.704). Cox proportional hazard models showed that PS better predicted long-term pain-free outcomes compared with HS (P < 0.05). One-year pain-free outcome was best predicted by pain type; longer-term outcomes were better predicted by presence and degree of neurovascular compression on preoperative imaging. CONCLUSIONS: PS is superior to HS in predicting pain-free outcomes after MVD, which may aid in patient selection and counseling. Overall, more significant neurovascular compression of the trigeminal nerve root, and to a lesser extent classical paroxysmal pain, are good predictors of durable pain relief after MVD.

Multidimensional Perioperative Recovery Trajectories in a Mixed Surgical Cohort: A Longitudinal Cluster Analysis Utilizing National Institutes of Health Patient-Reported Outcome Measurement Information System Measures.

BACKGROUND: Pain trajectories have been described in numerous surgical settings where preoperative characteristics have been used to predict trajectory membership. Suboptimal pain intensity trajectories have been linked to poor longitudinal outcomes. However, numerous biopsychosocial modulators of postoperative pain may also have distinct longitudinal trajectories that may inform additional targets to improve postoperative recovery. METHODS: Patients undergoing total joint arthroplasty, thoracic surgery, spine surgery, major abdominal surgery, or mastectomy completed Patient Reported Outcome Measurement Information System (PROMIS) measures and additional scales preoperatively and at 1 week, 2 weeks, 1 month, 3 months, and 6 months postoperatively. A k-means clustering for longitudinal data was utilized to explore and describe distinct pain impact (PROMIS Pain Interference and Physical Function) trajectories and associated changes in additional biopsychosocial measures. Follow-up analyses examined participant demographics and clinical characteristics associated with trajectory memberships. RESULTS: Three postoperative biopsychosocial symptom clusters were identified across all patients (n = 402): low (35%), average (47%), and high (18%) performance cluster trajectories. Participants undergoing total knee arthroplasty (TKA), spinal surgery, reporting presurgical opioid use, and higher pain catastrophizing scale scores were found to be associated with the low performance trajectory. Patients within the low performance trajectory, while demonstrating small improvements by 6 months, remained mild to moderately impaired in both pain impact and physical health outcomes. Alternatively, participants in the average performance trajectory demonstrated improvement in pain impact to population norms compared to baseline and demonstrated continued improvement across physical and psychological outcomes. Patients within the high performance cluster started within population norms across all measures at baseline and returned to baseline or exceeded baseline values by 6 months postoperatively. Self-reported opioid utilization was significantly higher in the low performance cluster across all time points. While a larger proportion of average performance patients reported opioid utilization during the first postoperative month compared to the high performance cluster, no differences were detected at 6 months postoperatively between these 2 clusters. CONCLUSIONS: These pain impact trajectories build upon previous unidimensional pain intensity trajectories and suggest that additional distinct biopsychosocial measures may have unique trajectories related to cluster assignment. Additionally, these findings highlight the importance of continued pain impact surveillance through the perioperative recovery period to detect patients at risk of experiencing a poor trajectory and subsequently poor longitudinal health outcomes.

Escala Multidimensional de Mensuração e de Avaliação de Dor (EMMADOR-SABER): percepção do conhecimento / Multidimensional Pain Measurement and Assessment Scale (EMMADOR-SABER): perception of knowledge

A dor é caracterizada como o quinto sinal vital e a capacitação dos profissionais de saúde torna-se fundamental para que o manejo seja realizado de forma efetiva, considerando que o fenômeno dor é multidimensional. Trata-se de pesquisa qualitativa. O foco de nossa geração de conhecimento está nos estudantes dos cursos de Enfermagem, Fisioterapia, Medicina, Odontologia e Psicologia, e profissionais docentes das mesmas áreas, tendo como propósito a identificação da percepção do conhecimento e o uso de instrumentos de mensuração e de avaliação de dor disponíveis na literatura. Foi desenvolvida a escala EMMADOR-SABER após o levantamento dos instrumentos. Após a validação quanto à aparência e conteúdo por 5 juízes convidados, foi realizado o teste piloto com 9 participantes. Em sua forma definitiva, 153 participantes responderam quais os instrumentos que conhecem e já fizeram uso na prática clínica, bem como indicar qual a importância atribuída a cada instrumento. O projeto foi encaminhado ao Comitê de Ética em Pesquisa da Escola de Enfermagem de Ribeirão Preto, em concordância com a Resolução número 466/2012. Os dados foram analisados qualitativamente de forma descritiva e apresentados por meio de gráficos e tabelas. Dentre os participantes da pesquisa, 73,2% foram docentes e 26,8% alunos. Os instrumentos referidos como mais conhecidos foram: Escala Analógica Visual (EVA), seguida da Escala Numérica, Escala Facial de Dor (FPS - R), Escala Descritiva ou Qualitativa e Questionário de McGill. Os instrumentos referidos como mais utilizados foram: Escala Analógica Visual (EVA), Escala Numérica (EN), Escala Facial de Dor (FPS-R), Escala Descritiva ou Qualitativa e Coloured Analogue Scale (CAS). A mediana da importância atribuída aos instrumentos foi de 7,10 numa escala de 0 a 10. O teste não paramétrico de Mann-Whitney verificou que não houve diferença estatisticamente significativa sobre o conhecimento e utilização dos instrumentos quando comparado o grupo de docentes com o grupo de alunos

Pain is characterized as the fifth vital sign and the training of health professionals is essential for effective management, considering that the pain phenomenon is multidimensional. This is qualitative research. The focus of our knowledge generation is on students of Nursing, Physiotherapy, Medicine, Dentistry and Psychology courses, and teaching professionals in the same areas, with the purpose of identifying the perception of knowledge and the use of measurement and evaluation instruments pain available in the literature. The EMMADOR-SABER scale was developed after surveying the instruments. After validation regarding appearance and content by 5 guest judges, a pilot test was carried out with 9 participants. In its definitive form, 153 participants answered which instruments they know and have already used in clinical practice, as well as indicating the importance attributed to each instrument. The project was sent to the Research Ethics Committee of the Ribeirão Preto School of Nursing, in accordance with Resolution number 466/2012. Data were qualitatively analyzed in a descriptive way and presented through graphs and tables. Among the research participants, 73.2% were professors and 26.8% were students. The instruments referred to as the best known were: Visual Analog Scale (VAS), followed by Numerical Scale, Facial Pain Scale (FPS - R), Descriptive or Qualitative Scale and McGill Questionnaire. The instruments referred to as the most used were: Visual Analogue Scale (VAS), Numerical Scale (EN), Facial Pain Scale (FPS-R), Descriptive or Qualitative Scale and Colored Analogue Scale (CAS). The median of importance attributed to the instruments was 7.10 on a scale from 0 to 10. The non-parametric Mann-Whitney test found that there was no statistically significant difference in the knowledge and use of the instruments when comparing the group of professors with the group of students

Postoperative Pain and Age: A Retrospective Cohort Association Study.

BACKGROUND: As the population ages, the number of elderly people undergoing surgery increases. Literature on the incidence and intensity of postoperative pain in the elderly is conflicting. This study examines associations between age and pain-related patient reported outcomes and perioperative pain management in a dataset of surgical patients undergoing four common surgeries: spinal surgery, hip or knee replacement, or laparoscopic cholecystectomy. Based on the authors' clinical experience, they hypothesize that pain scores are lower in older patients. METHODS: In this retrospective cohort, study data were collected between 2010 and 2018 as part of the international PAIN OUT program. Patients filled out the International Pain Outcomes Questionnaire on postoperative day 1. RESULTS: A total of 11,510 patients from 26 countries, 59% female, with a mean age of 62 yr, underwent one of the aforementioned types of surgery. Large variation was detected within each age group for worst pain, yet for each surgical procedure, mean scores decreased significantly with age (mean Numeric Rating Scale range, 6.3 to 7.3; ß = -0.2 per decade; P ≤ 0.001), representing a decrease of 1.3 Numeric Rating Scale points across a lifespan. The interference of pain with activities in bed, sleep, breathing deeply or coughing, nausea, drowsiness, anxiety, helplessness, opioid administration on the ward, and wish for more pain treatment also decreases with age for two or more of the procedures. Across the procedures, patients reported being in severe pain on postoperative day one 26 to 38% of the time, and pain interfered moderately to severely with movement. CONCLUSIONS: The authors' findings indicate that postoperative pain decreases with increasing age. The change is, however, small and of questionable clinical significance. Additionally, there are still too many patients, at any age, undergoing common surgeries who suffer from moderate to severe pain, which interferes with function, supporting the need for tailoring care to the individual patient.

Patient Satisfaction Following Minimally Invasive and Open Surgeries for Adult Spinal Deformity.

BACKGROUND: Patient satisfaction has become an important variable in assessing outcomes after spine surgery. Although minimally invasive surgery (MIS) techniques have become popular owing to reduced perioperative complications compared with open deformity surgery, whether patient-reported postoperative satisfaction differ between the 2 surgical approaches is unclear. The aim of this study was to characterize postoperative patient-reported outcomes (PRO) in patients who underwent open surgery or MIS for adult spinal deformity (ASD). METHODS: PRO scores were prospectively collected for patients undergoing deformity correction surgery between 2016 and 2018. Inclusion criteria were age >18 years, ASD, and completed PRO surveys. Patient demographic, clinical, and radiographic data and PRO survey responses were analyzed. A post hoc analysis comparing patients who were satisfied with their outcome and those who were unsatisfied was performed. RESULTS: Forty patients who underwent operative management of ASD (19 in the open surgery group and 21 in the MIS group) met the criteria for inclusion in this study. Patients in the MIS group reported higher mental health and self-image scores at 6 months; however, at the 12-month follow-up, both the open surgery and MIS groups reported minimal clinically important differences in back pain, leg pain, and functional status. Patient satisfaction scores did not differ based on surgical approach or intraoperative complications. CONCLUSIONS: PRO after open surgery and after MIS for ASD reflected successful outcomes with significant improvements in PRO survey scores but with subtle differences in the postoperative recovery process. The MIS group reported faster recovery with earlier improvement in self-image and mental health scores, which may stem from correction of smaller deformities. At the 12-month follow-up, postoperative satisfaction was high for the majority of patients in both groups.

Procedure-specific acute pain trajectory after elective total hip arthroplasty: systematic review and data synthesis.

BACKGROUND: For most procedures, there is insufficient evidence to guide clinicians in the optimal timing of advanced analgesic methods, which should be based on the expected time course of acute postoperative pain severity and aimed at time points where basic analgesia has proven insufficient. METHODS: We conducted a systematic search of the literature of analgesic trials for total hip arthroplasty (THA), extracting and pooling pain scores across studies, weighted for study size. Patients were grouped according to basic anaesthetic method used (general, spinal), and adjuvant analgesic interventions such as nerve blocks, local infiltration analgesia, and multimodal analgesia. Special consideration was given to high-risk populations such as chronic pain or opioid-dependent patients. RESULTS: We identified and analysed 71 trials with 5973 patients and constructed pain trajectories from the available pain scores. In most patients undergoing THA under general anaesthesia on a basic analgesic regimen, postoperative acute pain recedes to a mild level (<4/10) by 4 h after surgery. We note substantial variability in pain intensity even in patients subjected to similar analgesic regimens. Chronic pain or opioid-dependent patients were most often actively excluded from studies, and never analysed separately. CONCLUSIONS: We have demonstrated that it is feasible to construct procedure-specific pain curves to guide clinicians on the timing of advanced analgesic measures. Acute intense postoperative pain after THA should have resolved by 4-6 h after surgery in most patients. However, there is a substantial gap in knowledge on the management of patients with chronic pain and opioid-dependent patients.

Comparison between epidural and intravenous analgesia effects on disease-free survival after colorectal cancer surgery: a randomised multicentre controlled trial.

BACKGROUND: Thoracic epidural analgesia (TEA) has been suggested to improve survival after curative surgery for colorectal cancer compared with systemic opioid analgesia. The evidence, exclusively based on retrospective studies, is contradictory. METHODS: In this prospective, multicentre study, patients scheduled for elective colorectal cancer surgery between June 2011 and May 2017 were randomised to TEA or patient-controlled i.v. analgesia (PCA) with morphine. The primary endpoint was disease-free survival at 5 yr after surgery. Secondary outcomes were postoperative pain, complications, length of stay (LOS) at the hospital, and first return to intended oncologic therapy (RIOT). RESULTS: We enrolled 221 (110 TEA and 111 PCA) patients in the study, and 180 (89 TEA and 91 PCA) were included in the primary outcome. Disease-free survival at 5 yr was 76% in the TEA group and 69% in the PCA group; unadjusted hazard ratio (HR): 1.31 (95% confidence interval [CI]: 0.74-2.32), P=0.35; adjusted HR: 1.19 (95% CI: 0.61-2.31), P=0.61. Patients in the TEA group had significantly better pain relief during the first 24 h, but not thereafter, in open and minimally invasive procedures. There were no differences in postoperative complications, LOS, or RIOT between the groups. CONCLUSIONS: There was no significant difference between the TEA and PCA groups in disease-free survival at 5 yr in patients undergoing surgery for colorectal cancer. Other than a reduction in postoperative pain during the first 24 h after surgery, no other differences were found between TEA compared with i.v. PCA with morphine.

Lumbar disc herniation surgery: Is it worth adding interspinous spacer or instrumented fusion with regard to disc excision alone?

BACKGROUND: Discectomy is sometimes associated with recurrence of disc herniation and pain after surgery. The evidence to use an interspinous dynamic stabilization system or instrumented fusion in association with disc excision to prevent pain and re-operation remains controversial. In this study, we analyzed if adding interspinous spacer or fusion, offers advantages in relation to microdiscetomy alone. METHODS: Patients with lumbar disc herniation were divided in 3 groups; microdiscectomy alone (MD), microdiscectomy plus interspinous spacer (IS) and open discectomy plus posterior lumbar interbody fusion (PLIF). The clinical efficacy was measured using the Owestry Disability Index (ODI). Other outcome parameters including visual analogue scale for pain (VAS) back and legs, length of stay, direct in-hospital cost, 90-day complication rate, and 1-year re-operation rate were also evaluated. RESULTS: A total of 103 patients whose mean age was 39.1 (±8.5) years were included. A significant improvement of the ODI and VAS back and legs pain baseline score was detected in the 3 groups. After 1 year, no significant differences in ODI, VAS back and legs pain were found between the 3 groups. There was an increase of 169% of the total direct in- hospital cost in IS group and 287% in PLIF group, in relation to MD (p < 0.001). Length of stay was 86% higher in the IS group and 384% longer in the PLIF group compared to MD (p < 0.001). The 1 year re-operation rates were 5.6%, 10% and 16.2% (p = 0.33). Discectomy seems to be the main responsible for the clinical improvement, without the interspinous spacer or fusion adding any benefit. The addition of interspinous spacer or fusion increased direct in-hospital cost, length of stay, and did not protect against re-operation.

Epidural analgesia for postoperative pain: Improving outcomes or adding risks?

Current evidence shows that the benefits of epidural analgesia (EA) are not as impressive as believed in the past, while the risks of adverse effects and serious complications are greater than previously estimated. There are many reasons for the decreasing role of epidural technique in clinical practice (table). Indeed, EA can cause harm and hinder early mobilization in enhanced recovery after surgery (ERAS) programmes. Some ERAS interventions are complex, confusing, sometimes contradictory and apparently unimplementable. In spite of much hype and after almost 25 years, the originator of the concept has described the current status of ERAS as 'far from good'. Outpatient surgery setup has been a remarkable success for many major surgical procedures, and it predates ERAS and appears to be a simpler and better model for reducing postoperative morbidity and hospitalization times. Systematic reviews of comparative studies have shown that less invasive and safer but equally effective alternatives to EA are available for almost all major surgical procedures. These include: paravertebral block, peripheral nerve blocks, catheter wound infusion, periarticular local infiltration analgesia, preperitoneal catheters and transversus abdominis plane block. Increasingly, these non-EA methods are being used as surgeon-delivered regional analgesia (RA) techniques. This encouraging trend of active surgeon participation, with anaesthesiologist collaboration, will undoubtedly improve the decades-old twin problems of underused RA techniques and undertreated postoperative pain. The continued use of EA at any institution can only be justified by results from its own audits; however, regrettably only very few institutions perform such regular audits.

A Systematic Review of Assessments and Interventions for Chronic Pain in Young Children With or at High Risk for Cerebral Palsy.

BACKGROUND: Pain is common in children with cerebral palsy. The purpose of this systematic review was to evaluate the evidence regarding assessments and interventions for chronic pain in children aged ≤2 years with or at high risk for cerebral palsy. METHODS: A comprehensive literature search was performed. Included articles were screened using PRISMA guidelines and quality of evidence was reviewed using best-evidence tools by independent reviewers. Using social media channels, an online survey was conducted to elicit parent preferences. RESULTS: Six articles met criteria. Parent perception was an assessment option. Three pharmacologic interventions (gabapentin, medical cannabis, botulinum toxin type A) and 1 nonpharmacologic intervention were identified. Parent survey report parent-comfort and other nonpharmacologic interventions ranked as most preferable. CONCLUSION: A conditional GRADE recommendation was in favor of parent report for pain assessment. Clinical trials are sorely needed because of the lack of evidence for safety and efficacy of pharmacologic interventions.

Age as a Predictor for Complications and Patient-reported Outcomes in Multilevel Transforaminal Lumbar Interbody Fusions: Analyses From the Michigan Spine Surgery Improvement Collaborative (MSSIC).

STUDY DESIGN: Retrospective review of a multi-institutional data registry. OBJECTIVE: The authors sought to determine the association between age and complications & patient-reported outcomes (PRO) in patients undergoing multilevel transforaminal interbody lumbar fusion (MTLIF). SUMMARY OF BACKGROUND DATA: Elderly patients undergoing MTLIF are considered high risk. However, data on complications and PRO are lacking. Additionally, safety of multilevel lumbar fusion in the elderly remains uncertain. METHODS: Patients ≥50-year-old who underwent MTLIF for degenerative lumbar spine conditions were analyzed. Ninety-day complications and PROs (baseline, 90-d, 1-y, 2-y) were queried using the MSSIC database. PROs were measured by back & leg visual analog scale (VAS), Patient-reported Outcomes Measurement Information System (PROMIS), EuroQol-5D (EQ-5D), and North American Spine Society (NASS) Patient Satisfaction Index. Univariate analyses were used to compare among elderly and complication cohorts. Generalized estimating equation (GEE) was used to identify predictors of complications and PROs. RESULTS: A total of 3120 patients analyzed with 961 (31%) ≥ 70-y-o and 2159 (69%) between 50-69. A higher proportion of elderly experienced postoperative complications (P = .003) including urinary retention (P = <.001) and urinary tract infection (P = .002). Multivariate analysis demonstrated that age was not independently associated with complications. Number of operative levels was associated with any (P = .001) and minor (P = .002) complication. Incurring a complication was independently associated with worse leg VAS and PROMIS scores (P = <.001). Preoperative independent ambulation was independently associated with improved PROMIS, and EQ5D (P = <.001). Within the elderly, preoperative independent ambulation and lower BMI were associated with improved PROMIS (P = <.001). Complications had no significant effect on PROs in the elderly. CONCLUSIONS: Age was not associated with complications nor predictive of functional outcomes in patients who underwent MTLIF. Age alone, therefore, may not be an appropriate surrogate for risk. Furthermore, baseline preoperative independent ambulation was associated with better clinical outcomes and should be considered during preoperative surgical counseling.Level of Evidence: 3.

Ketorolac plus Lidocaine vs Lidocaine for pain relief following core needle soft tissue biopsy: A CONSORT-compliant double-blind randomized controlled study.

BACKGROUNDS: The main objective of this study was to compare the pain control efficacy of local administration of Lidocaine with or without the nonsteroidal anti-inflammatory drug, Ketorolac, and local conventional Lidocaine injection in core needle biopsy of the musculoskeletal tumor. METHODS: The current study was a randomized, double-blind controlled clinical trial that included 128 patients with suspected musculoskeletal tumors. Patients were randomly assigned to either the Ketorolac plus Lidocaine (n = 64) or Lidocaine group (n = 64). The Ketorolac - Lidocaine combination syringe contained 30 mg Ketorolac and 2% Lidocaine - adrenaline dosage, and the Lidocaine syringe contained 2% Lidocaine - adrenaline dosage. The level of pain after core needle biopsy was evaluated for each patient at 1, 6, 12, 24, 48, and >48 hours by a Visual Analog Scale (VAS). The mean VAS changes over time were compared between the Ketorolac plus Lidocaine and Lidocaine groups using a linear mixed model. RESULTS: baseline information including mean age of patients in Lidocaine group (51.5 ±â€Š19.4 years) and in Lidocaine - Ketorolac combination group (50.1 ±â€Š18 years), diagnosis (malignant, benign, metastatic, infection), tumor location (upper and lower extremities, back), VAS score 1-hour post-operation (mild and moderate pain) were noted. The VAS score ratings were significantly lower in Lidocaine - Ketorolac combination group when compared to the Lidocaine group during the 1 to 24 hours post-operation time period. CONCLUSION: Patients receiving Lidocaine - Ketorolac combination dosage had significantly lower VAS scores, and these results confirm that local injection of Lidocaine - Ketorolac combination had a superior pain-controlling effect during the first 24 hours after the biopsy procedure in comparison to Lidocaine injection alone, as measured by VAS score scale.

Comparative study of verbal rating scale and numerical rating scale to assess postoperative pain intensity in the post anesthesia care unit: A prospective observational cohort study.

ABSTRACT: Postsurgical patients usually have difficulty in answering the self-report pain scales due to the residual effects of anesthetic or sedative agents in the post-anesthesia care unit (PACU). A comparative analysis of pain assessment tools used in the PACU is lacking.In this prospective observational study, we compared the intensity of pain using the 11-point numeric rating scale (NRS) and the 4-category verbal rating scale (VRS) thrice, 5 minutes after PACU admission, 20 minutes after the first assessment, and just before discharge from the PACU in 200 patients undergone surgery. Spearman rank correlation analysis was used to investigate the correlation between 2 scales, and the weighted kappa (κ) coefficient was performed to evaluate inter-scale reliability. Response rates of the 2 scales were also compared.VRS and NRS were highly correlated during all 3 comparisons (r = 0.767, 0.714, and 0.653, respectively; P < .0001). Each category of VRS showed a statistically significant difference in pain intensity measured by NRS during all 3 assessments. Inter-scale reliability had a fair strength of agreement for all 3 measurements (weighted κ = 0.519, 95% CI: 0.421-0.618; weighted κ = 0.511, 95% C.I: 0.409-0.613; weighted κ = 0.452, 95% C.I: 0.352-0.551, respectively). VRS showed a higher response rate for PACU patients compared to NRS in all 3 measurements (96% vs 77.5%, 99% vs 81.5%, and 96.5% vs 86.5%, respectively; P < .0001).In the PACU, VRS is a reasonable and practical pain intensity measurement tool for postsurgical patients, considering the high correlation between VRS and NRS, and a higher response rate.

Factors associated with rebound pain after peripheral nerve block for ambulatory surgery.

BACKGROUND: Rebound pain is a common, yet under-recognised acute increase in pain severity after a peripheral nerve block (PNB) has receded, typically manifesting within 24 h after the block was performed. This retrospective cohort study investigated the incidence and factors associated with rebound pain in patients who received a PNB for ambulatory surgery. METHODS: Ambulatory surgery patients who received a preoperative PNB between March 2017 and February 2019 were included. Rebound pain was defined as the transition from well-controlled pain (numerical rating scale [NRS] ≤3) while the block is working to severe pain (NRS ≥7) within 24 h of block performance. Patient, surgical, and anaesthetic factors were analysed for association with rebound pain by univariate, multivariable, and machine learning methods. RESULTS: Four hundred and eighty-two (49.6%) of 972 included patients experienced rebound pain as per the definition. Multivariable analysis showed that the factors independently associated with rebound pain were younger age (odds ratio [OR] 0.98; 95% confidence interval [CI] 0.97-0.99), female gender (OR 1.52 [1.15-2.02]), surgery involving bone (OR 1.82 [1.38-2.40]), and absence of perioperative i.v. dexamethasone (OR 1.78 [1.12-2.83]). Despite a high incidence of rebound pain, there were high rates of patient satisfaction (83.2%) and return to daily activities (96.5%). CONCLUSIONS: Rebound pain occurred in half of the patients and showed independent associations with age, female gender, bone surgery, and absence of intraoperative use of i.v. dexamethasone. Until further research is available, clinicians should continue to use preventative strategies, especially for patients at higher risk of experiencing rebound pain.

Posterior decompression and fusion versus laminoplasty for cervical ossification of posterior longitudinal ligament: a systematic review and meta-analysis.

Both posterior decompression and fusion (PDF) and laminoplasty (LAMP) have been used to treat cervical myelopathy due to multilevel ossification of posterior longitudinal ligament (OPLL). However, considerable controversy exists over the choice of the two surgical strategies. Thus, the aim of this study is to compare clinical outcomes of PDF and LAMP for treatment of cervical myelopathy due to multilevel OPLL. We searched PubMed, EMBASE and Cochrane Central Register of Controlled Trials database to identify relevant clinical studies compared with clinical outcomes of PDF and LAMP for cervical OPLL. The primary outcomes including Japanese Orthopaedic Association (JOA) score and recovery rate of JOA were evaluated, and the secondary outcomes involving visual analogue scale (VAS), cervical curvature, OPLL progression rate, complication rate, reoperation rate and surgical trauma were also evaluated using Stata software. A total of nine studies were included in the current study, involving 324 patients. The current study suggests that compared with LAMP, PDF achieves a lower OPLL progression rate, better postoperative cervical curvature and similar neurological improvement in the treatment of multilevel cervical OPLL. However, PDF has a higher complication rate, more surgical trauma and higher postoperative VAS than LAMP.

Does the Predominant Pain Location Influence Functional Outcomes, Satisfaction and Return to Work After Anterior Cervical Discectomy and Fusion for Cervical Radiculopathy?

STUDY DESIGN: Retrospective review of prospectively-collected registry data. OBJECTIVES: The aim of this study was to determine how different combinations of preoperative neck pain (NP) and arm pain (AP) influence functional outcomes, patient satisfaction, and return-to-work in patients undergoing anterior cervical discectomy and fusion (ACDF) for degenerative cervical radiculopathy (DCR). SUMMARY OF BACKGROUND DATA: Surgeons often base decisions on the traditional belief that the predominance of radicular upper extremity symptoms is a stronger indication for cervical spine surgery than axial pain. However, there is a paucity of literature supporting this notion. METHODS: A prospectively maintained registry was reviewed for all patients who underwent primary ACDF for DCR. Patients were categorized into three groups depending on predominant pain location: AP predominant ([APP]; AP > NP), NP predominant ([NPP]; NP > AP), and equal pain predominance ([EPP]; NP = AP). Patients were prospectively followed for at least 2 years. RESULTS: In total, 303 patients were included: 27.4% APP, 38.9% NPP, and 33.7% EPP cases. The APP group was significantly older (P = 0.030), although there were no other preoperative differences among the three groups. After adjusting for baseline differences, the SF-36 Physical Component Summary was significantly better in the APP group at 6 months (P = 0.048) and 2 years (P = 0.039). In addition, they showed a trend towards better 6-month Neck Disability Index (P = 0.077) and 2-year SF-36 Mental Component Summary (P = 0.059). However, an equal proportion of patients in each group achieved the Minimal Clinically Important Difference for each outcome, were satisfied, and returned to work 2 years after surgery. CONCLUSION: Although patients with NPP had slightly poorer function and quality of life, all patients experienced a clinically meaningful improvement in patient-reported outcomes, regardless of the predominant pain location. High rates of satisfaction and return-to-work were also achieved. In the context of proper indications, these findings suggest that ACDF can be equally effective for DCR patients with varying combinations of NP or AP.Level of Evidence: 3.

Contemporary Analysis of Minimal Clinically Important Difference in the Neurosurgical Literature.

BACKGROUND: Minimal clinically important difference (MCID) is determined when a patient or physician defines the minimal change that outweighs the costs and untoward effects of a treatment. These measurements are "anchored" to validated quality-of-life instruments or physician-rated, disease-activity indices. To capture the subjective clinical experience in a measurable way, there is an increasing use of MCID. OBJECTIVE: To review the overall concept, method of calculation, strengths, and weaknesses of MCID and its application in the neurosurgical literature. METHODS: Recent articles were reviewed based on PubMed query. To illustrate the strengths and limitations of MCID, studies regarding the measurement of pain are emphasized and their impact on subsequent publications queried. RESULTS: MCID varies by population baseline characteristics and calculation method. In the context of pain, MCID varied based on the quality of pain, chronicity, and treatment options. CONCLUSION: MCID evaluates outcomes relative to whether they provide a meaningful change to patients, incorporating the risks and benefits of a treatment. Using MCID in the process of evaluating outcomes helps to avoid the error of interpreting a small but statistically significant outcome difference as being clinically important.

Pain During Sex Before and After Surgery for Lumbar Disc Herniation: A Multicenter Observational Study.

STUDY DESIGN: Observational multicenter study. OBJECTIVE: The aim of this study was to evaluate changes in pain during sexual activity after surgery for lumbar disc herniation (LDH). SUMMARY OF BACKGROUND DATA: There are limited data available on sexual function in patients undergoing surgery for LDH. METHODS: Data were retrieved from the Norwegian Registry for Spine Surgery. The primary outcome was change in pain during sexual activity at one year, assessed by item number eight of the Oswestry disability index (ODI) questionnaire. Secondary outcome measures included ODI, EuroQol-5D (EQ-5D), and numeric rating scale (NRS) scores for back and leg pain. RESULTS: Among the 18,529 patients included, 12,103 (64.8%) completed 1-year follow-up. At baseline, 16,729 patients (90.3%) provided information about pain during sexual activity, whereas 11,130 (92.0%) among those with complete follow-up completed this item. Preoperatively 2586 of 16,729 patients (15.5%) reported that pain did not affect sexual activity and at 1 year, 7251 of 11,130 patients (65.1%) reported a normal sex-life without pain. Preoperatively, 2483 (14.8%) patients reported that pain prevented any sex-life, compared to 190 patients (1.7%) at 1 year. At baseline, 14,143 of 16,729 patients (84.5%) reported that sexual activity caused pain, and among these 7232 of 10,509 responders (68.8%) reported an improvement at 1 year. A multivariable regression analysis showed that having a life partner, college education, working until time of surgery, undergoing emergency surgery, and increasing ODI score were predictors of improvement in pain during sexual activity. Increasing age, tobacco smoking, increasing body mass index, comorbidity, back pain >12 months, previous spine surgery, surgery in two or more lumbar levels, and complications occurring within 3 months were negative predictors. CONCLUSION: This study clearly demonstrates that a large proportion of patients undergoing surgery for LDH experienced an improvement in pain during sexual activity at 1 year. LEVEL OF EVIDENCE: 2.

The effect of dry needling on gastrocnemius muscle stiffness and strength in participants with latent trigger points.

Abnormal muscle stiffness is a potential complication after injury and identifying interventions that modify muscle stiffness may be useful to promote recovery. The purpose of this study was to identify the short-term effects of dry needling (DN) on resting and contracted gastrocnemius muscle stiffness and strength of the triceps surae in individuals with latent myofascial trigger points (MTrPs). In this randomized controlled trial, 52 individuals received two DN treatment sessions to latent MTrPs and 50 individuals received two sham needling sessions. Resting and contracted muscle stiffness were assessed both at the treatment site and a standardized central site in the medial gastrocnemius head immediately post-treatment and one week after the last session. There were significant group by time interactions for resting muscle stiffness at the site of the MTrP (p = .03), but not at the central site (p = .29). Post-needling between group comparison indicated that the DN group had significantly lower resting muscle stiffness at the site of the MTrP than the sham group after adjusting for baseline differences. There were no significant between group differences in contracted muscle stiffness or muscle strength. Identifying strategies that can reduce aberrant muscle stiffness may help to guide management of individuals with neuromuscular pain-related conditions. Level of evidence: Therapy, level 2.