Our primary objective is to provide the clinical informatics community with an introductory tutorial on calibration measurements and calibration models for predictive models using existing R packages and custom implemented code in R on real and simulated data. Clinical predictive model performance is commonly published based on discrimination measures, but use of models for individualized predictions requires adequate model calibration. This tutorial is intended for clinical researchers who want to evaluate predictive models in terms of their applicability to a particular population. It is also for informaticians and for software engineers who want to understand the role that calibration plays in the evaluation of a clinical predictive model, and to provide them with a solid starting point to consider incorporating calibration evaluation and calibration models in their work. Covered topics include (1) an introduction to the importance of calibration in the clinical setting, (2) an illustration of the distinct roles that discrimination and calibration play in the assessment of clinical predictive models, (3) a tutorial and demonstration of selected calibration measurements, (4) a tutorial and demonstration of selected calibration models, and (5) a brief discussion of limitations of these methods and practical suggestions on how to use them in practice.

Introduction:The objective of the present feasibility study was to investigate the use of a new treatment modality-percutaneous peripheral nerve stimulation (PNS)-in controlling the often severe and long-lasting pain following total knee arthroplasty (TKA).Methods: For patients undergoing a primary, unilateral TKA, both femoral and sciatic open-coil percutaneous leads (SPR Therapeutics, Cleveland, OH) were placed up to seven days prior to surgery using ultrasound guidance. The leads were connected to external stimulators and used both at home and in the hospital for up to six weeks total.Results: In six of seven subjects (86%), the average of daily pain scores across the first two weeks was <4 on the 0-10 Numeric Rating Scale for pain. A majority of subjects (four out of seven; 57%) had ceased opioid use within the first week (median time to opioid cessation for all subjects was six days). Gross sensory/motor function was maintained during stimulation, enabling stimulation during physical therapy and activities of daily living. At 12 weeks following surgery, six of seven subjects had improved by >10% on the Six-Minute Walk Test compared to preoperative levels, and WOMAC scores improved by an average of 85% compared to before surgery. No falls, motor block, or lead infections were reported.Conclusions: This feasibility study suggests that for TKA, ultrasound-guided percutaneous PNS is feasible in the immediate perioperative period and may provide analgesia without the undesirable systemic effects of opioids or quadriceps weakness induced by local anesthetics-based peripheral nerve blocks.

Background and Purpose-To evaluate whether increased neuroimaging use is associated with increased brain arteriovenous malformation (BAVM) detection, we examined detection rates in the Kaiser Permanente Medical Care Program of northern California between 1995 and 2004. Methods-We reviewed medical records, radiology reports, and administrative databases to identify BAVMs, intracranial aneurysms (IAs: subarachnoid hemorrhage [SAH] and unruptured aneurysms), and other vascular malformations (OVMs: dural fistulas, cavernous malformations, Vein of Galen malformations, and venous malformations). Poisson regression (with robust standard errors) was used to test for trend. Random-effects meta-analysis generated a pooled measure of BAVM detection rate from 6 studies. Results-We identified 401 BAVMs (197 ruptured, 204 unruptured), 570 OVMs, and 2892 IAs (2079 SAHs and 813 unruptured IAs). Detection rates per 100 000 person-years were 1.4 (95% CI, 1.3 to 1.6) for BAVMs, 2.0 (95% CI, 1.8 to 2.3) for OVMs, and 10.3 (95% CI, 9.9 to 10.7) for IAs. Neuroimaging utilization increased 12% per year during the time period (PϽ0.001). Overall, rates increased for IAs (PϽ0.001), remained stable for OVMs (Pϭ0.858), and decreased for BAVMs (Pϭ0.001). Detection rates increased 15% per year for unruptured IAs (PϽ0.001), with no change in SAHs (Pϭ0.903). However, rates decreased 7% per year for unruptured BAVMs (Pϭ0.016) and 3% per year for ruptured BAVMs (Pϭ0.005). Meta-analysis yielded a pooled BAVM detection rate of 1.3 (95% CI, 1.2 to 1.4) per 100 000 person-years, without heterogeneity between studies (Pϭ0.25). Key Words: brain AVM Ⅲ cerebral aneurysm Ⅲ vascular malformation Ⅲ incidence Ⅲ MRI B rain arteriovenous malformations (BAVMs) are lesions of the cerebral vasculature in which arterial blood flow is shunted directly into the venous system without passing through a capillary system, resulting in high-flow lesions prone to rupture. The estimated detection rate of BAVMs has been reported to be Ϸ1 per 100 000 person-years, accounting for 1% to 2% of all strokes. 1 In order of decreasing frequency, the clinical presentations of BAVMs include hemorrhage, seizures, headaches, and neurologic deficits. 2 The primary management aspect of BAVMs is prevention of rupture and the resulting intracranial hemorrhagic event. 3 The annual risk of intracranial hemorrhage after diagnosis of BAVMs is Ϸ2% to 4% per year; the rate is higher for those with initially ruptured and lower for those with unruptured presentations. 1,4,5 BAVMs that do not bleed can cause seizures, headaches, or neurologic deficits due to a mass effect and involvement of neighboring eloquent brain regions. 3,6 Initial discovery of BAVMs in patients usually follows clinical presentation, most commonly hemorrhage from a ruptured lesion. Advances in neuroimaging techniques, including magnetic resonance imaging (MRI), computed tomography (CT), and cerebral angiography, have provided improved resolution for detecting and evaluating BAVMs. [7][8][9] With the ability to detect ...

This proof of concept study demonstrates that percutaneous femoral nerve stimulation is feasible for ambulatory knee surgery; and suggests that this modality may be effective in providing analgesia and decreasing opioid requirements following anterior cruciate ligament reconstruction. clinicaltrials.gov: NCT02898103.

Limiting the spread of the disease is key to controlling the COVID-19 pandemic. This includes identifying people who have been exposed to COVID-19, minimizing patient contact, and enforcing strict hygiene measures. To prevent healthcare systems from becoming overburdened, elective and non-urgent medical procedures and treatments have been postponed, and primary health care has broadened to include virtual appointments via telemedicine. Although telemedicine precludes the physical examination of a patient, it allows collection of a range of information prior to a patient's admission, and may therefore be used in preoperative assessment. This new tool can be used to evaluate the severity and progression of the main disease, other comorbidities, and the urgency of the surgical treatment as well as preferencing anesthetic procedures. It can also be used for effective screening and triaging of patients with suspected or established COVID-19, thereby protecting other patients, clinicians and communities alike.

BackgroundParavertebral nerve blocks (PVBs) are frequently used to treat pain during and following breast surgery, but have various undesirable risks such as pneumothorax. The erector spinae plane block (ESPB) also provides perioperative breast analgesia, but is purported to be easier to administer with a favorable safety profile. However, it remains unknown if the new ESPB provides comparable analgesia as the decades-old PVB technique.MethodsSubjects undergoing unilateral or bilateral non-mastectomy breast surgery were randomized to a single-injection ESPB or PVB in a subject-blinded fashion (ropivacaine 0.5% with epinephrine; 20 mL unilateral or 16 mL/side for bilateral). We hypothesized that (1) analgesia would be non-inferior in the recovery room as measured on a Numeric Rating Scale (NRS) with ESPB, and (2) opioid consumption would be non-inferior in the operating and recovery rooms with ESPB.ResultsBoth pain scores and opioid consumption were higher in subjects with ESPBs (n=50) than PVBs (n=50; median NRS 3.0 vs 0; 95% CI −3.0 to 0; p=0.0011; and median morphine equivalents 2.0 vs 1.5 mg; 95% CI −1.2 to −0.1; p=0.0043). No block-related adverse events occurred in either group.ConclusionsPVBs provided superior analgesia and reduced opioid requirements following non-mastectomy breast surgery. To compare the relatively rare complications between the techniques will require a sample size 1–2 orders of magnitude greater than the current investigation; however, without a dramatic improvement in safety profile for ESPBs, it appears that PVBs are superior to ESPBs for postoperative analgesia after non-mastectomy breast surgery.Trial registration numberNCT03549234.

Background and objectivesPercutaneous peripheral nerve stimulation (PNS) is an analgesic modality involving the insertion of a lead through an introducing needle followed by the delivery of electric current. This modality has been reported to treat chronic pain as well as postoperative pain following knee and foot surgery. However, it remains unknown if this analgesic technique may be used in ambulatory patients following upper extremity surgery. The purpose of this proof-of-concept study was to investigate various lead implantation locations and evaluate the feasibility of using percutaneous brachial plexus PNS to treat surgical pain following ambulatory rotator cuff repair in the immediate postoperative period.MethodsPreoperatively, an electrical lead (SPR Therapeutics, Cleveland, Ohio) was percutaneously implanted to target the suprascapular nerve or brachial plexus roots or trunks using ultrasound guidance. Postoperatively, subjects received 5 min of either stimulation or sham in a randomized, double-masked fashion followed by a 5 min crossover period, and then continuous stimulation until lead removal postoperative days 14–28.ResultsLeads (n=2) implanted at the suprascapular notch did not appear to provide analgesia, and subsequent leads (n=14) were inserted through the middle scalene muscle and placed to target the brachial plexus. Three subjects withdrew prior to data collection. Within the recovery room, stimulation did not decrease pain scores during the first 40 min of the remaining subjects with brachial plexus leads, regardless of which treatment subjects were randomized to initially. Seven of these 11 subjects required a single-injection interscalene nerve block for rescue analgesia prior to discharge. However, subsequent average resting and dynamic pain scores postoperative days 1–14 had a median of 1 or less on the Numeric Rating Scale, and opioid requirements averaged less than 1 tablet daily with active stimulation. Two leads dislodged during use and four fractured on withdrawal, but no infections, nerve injuries, or adverse sequelae were reported.ConclusionsThis proof-of-concept study demonstrates that ultrasound-guided percutaneous PNS of the brachial plexus is feasible for ambulatory shoulder surgery, and although analgesia immediately following surgery does not appear to be as potent as local anesthetic-based peripheral nerve blocks, the study suggests that this modality may provide analgesia and decrease opioid requirements in the days following rotator cuff repair. Therefore, it suggests that a subsequent, large, randomized clinical trial with an adequate control group is warranted to further investigate this therapy in the management of surgical pain in the immediate postoperative period. However, multiple technical issues remain to be resolved, such as the optimal lead location, insertion technique, and stimulating protocol, as well as preventing lead dislodgment and fracture.Trial registration number NCT02898103.

Introduction: There are various important implications associated with poorly controlled postoperative pain in the adult surgical patientthis includes cardiopulmonary complications, opioid-related side effects, unplanned hospital admissions, prolonged hospital stay, and the subsequent development of chronic pain or opioid addiction. With the ongoing national opioid crisis, it is imperative that perioperative providers implement pathways for surgical patients that reduce opioid requirements and painrelated complications. Areas covered: In this review, the authors discuss the components of a multimodal opioid-sparing analgesia pathway as it pertains to the perioperative environment. Medications reviewed include gabapentinoids, acetaminophen, non-steroidal anti-inflammatory drugs, ketamine, intravenous lidocaine, dexmedetomidine, and glucocorticoids. The use of peripheral nerve blocks and neuraxial analgesia are also discussed. Expert opinion: In appropriate cases, regional anesthetic interventions are extremely useful for postoperative analgesia, including peripheral nerve blocks and neuraxial analgesia and while newer postoperative analgesics have been postulated, the literature on such is presently controversial. Coordinated approaches to pain management are recommended to reduce the need for opioids and to improve patient satisfaction post-surgery.