Enhanced Recovery After Surgery (ERAS) Spine Pathways and the Role of Perioperative Checklists.

Enhanced recovery after surgery (ERAS) proposes a multimodal, evidence-based approach to perioperative care. ERAS pathways have been shown to help reduce complications, hospital length of stay (LOS), 30-day readmission rates, pain scores, and ultimately surgical costs, while improving patient satisfaction scores and outcomes in multiple surgical subspecialties [1-6]. Numerous specialties have implemented ERAS programs across the globe, providing a foundation for spine surgeons to begin the process themselves. Over the last few years, a significant number of papers have been addressing ERAS pathways for spinal surgery [7-19]. The majority have addressed the lumbar spine [9, 20-26]. The number of cervical ERAS pathways has been limited [27-29]. Many spine programs have begun the implementation of ERAS pathways, incorporating principles and interventions to various spine surgical procedures. Although differences in implementation across programs exist, there are a few common elements that promote a successful enhanced recovery approach [11, 16, 23, 25, 30-33]. All spinal ERAS pathways have three major elements, which are preoperative, perioperative, and postoperative phases. Within these phases some common elements include preoperative and intraoperative surgical checklists. Intraoperative checklist in addition to the "surgical time out" has been integrated into the workflow of most hospitals doing surgeries and have become a standard of care. The surgical checklist is designed to help reduce surgical errors and prevent wrong site/patient surgeries. Several surgical checklists have been developed throughout the years. Despite these safety protocols wrong site/level and other surgical errors continue to occur. Many cases of wrong level spine surgery (WLSS) still occur even when intraoperative imaging is performed [34, 35]. One survey reported that about 50% of spine surgeons have performed at least one WLSS during their career [36, 37]. Another survey reported that 36% of spine surgeons had performed at least one WLSS that was not recognized intraoperatively [38]. On a similar account, about 30% of spine surgery fellows have experienced wrong-site surgery [39]. From raw incidence rates, WLSS may seem rare, but these surveys show that the experience of WLSS is rather common among spine surgeons. WLSS is not yet a "never event." This may be due to poor quality of the intraoperative images, hindering subsequent level identification [34, 35, 38, 40]. Errors in interpretation of the imaging may also occur, including inconsistency in numbering vertebrae, inconsistency in landmark usage for level counting, and problems with numbering vertebrae due to lumbosacral transitional vertebrae (LSTV) and other anatomical variants [34, 38, 41-43]. This chapter will describe a framework for the development and implementation of ERAS pathway for patients undergoing spine surgery. In addition, we will propose preoperative imaging guidelines and a comprehensive spine surgical checklist to incorporate into the perioperative phase to help reduce further surgical errors and WLSS.

Evaluation of the safety, accuracy, and helpfulness of the GPT-4.0 Large Language Model in neurosurgery.

BACKGROUND: Although prior work demonstrated the surprising accuracy of Large Language Models (LLMs) on neurosurgery board-style questions, their use in day-to-day clinical situations warrants further investigation. This study assessed GPT-4.0's responses to common clinical questions across various subspecialties of neurosurgery. METHODS: A panel of attending neurosurgeons formulated 35 general neurosurgical questions spanning neuro-oncology, spine, vascular, functional, pediatrics, and trauma. All questions were input into GPT-4.0 with a prespecified, standard prompt. Responses were evaluated by two attending neurosurgeons, each on a standardized scale for accuracy, safety, and helpfulness. Citations were indexed and evaluated against identifiable database references. RESULTS: GPT-4.0 responses were consistent with current medical guidelines and accounted for recent advances in the field 92.8 % and 78.6 % of the time respectively. Neurosurgeons reported GPT-4.0 responses providing unrealistic information or potentially risky information 14.3 % and 7.1 % of the time respectively. Assessed on 5-point scales, responses suggested that GPT-4.0 was clinically useful (4.0 ± 0.6), relevant (4.7 ± 0.3), and coherent (4.9 ± 0.2). The depth of clinical responses varied (3.7 ± 0.6), and "red flag" symptoms were missed 7.1 % of the time. Moreover, GPT-4.0 cited 86 references (2.46 citations per answer), of which only 50 % were deemed valid, and 77.1 % of responses contained at least one inappropriate citation. CONCLUSION: Current general LLM technology can offer generally accurate, safe, and helpful neurosurgical information, but may not fully evaluate medical literature or recent field advances. Citation generation and usage remains unreliable. As this technology becomes more ubiquitous, clinicians will need to exercise caution when dealing with it in practice.

Defining benchmark outcomes for mesial temporal lobe epilepsy surgery: A global multicenter analysis of 1119 cases.

OBJECTIVE: Benchmarking has been proposed to reflect surgical quality and represents the highest standard reference values for desirable results. We sought to determine benchmark outcomes in patients after surgery for drug-resistant mesial temporal lobe epilepsy (MTLE). METHODS: This retrospective multicenter study included patients who underwent MTLE surgery at 19 expert centers on five continents. Benchmarks were defined for 15 endpoints covering surgery and epilepsy outcome at discharge, 1 year after surgery, and the last available follow-up. Patients were risk-stratified by applying outcome-relevant comorbidities, and benchmarks were calculated for low-risk ("benchmark") cases. Respective measures were derived from the median value at each center, and the 75th percentile was considered the benchmark cutoff. RESULTS: A total of 1119 patients with a mean age (range) of 36.7 (1-74) years and a male-to-female ratio of 1:1.1 were included. Most patients (59.2%) underwent anterior temporal lobe resection with amygdalohippocampectomy. The overall rate of complications or neurological deficits was 14.4%, with no in-hospital death. After risk stratification, 377 (33.7%) benchmark cases of 1119 patients were identified, representing 13.6%-72.9% of cases per center and leaving 742 patients in the high-risk cohort. Benchmark cutoffs for any complication, clinically apparent stroke, and reoperation rate at discharge were ≤24.6%, ≤.5%, and ≤3.9%, respectively. A favorable seizure outcome (defined as International League Against Epilepsy class I and II) was reached in 83.6% at 1 year and 79.0% at the last follow-up in benchmark cases, leading to benchmark cutoffs of ≥75.2% (1-year follow-up) and ≥69.5% (mean follow-up of 39.0 months). SIGNIFICANCE: This study presents internationally applicable benchmark outcomes for the efficacy and safety of MTLE surgery. It may allow for comparison between centers, patient registries, and novel surgical and interventional techniques.

Non-navigated 2D intraoperative ultrasound: An unsophisticated surgical tool to achieve high standards of care in glioma surgery.

PURPOSE: In an era characterized by rapid progression in neurosurgical technologies, traditional tools such as the non-navigated two-dimensional intraoperative ultrasound (nn-2D-IOUS) risk being overshadowed. Against this backdrop, this study endeavors to provide a comprehensive assessment of the clinical efficacy and surgical relevance of nn-2D-IOUS, specifically in the context of glioma resections. METHODS: This retrospective study undertaken at a single center evaluated 99 consecutive, non-selected patients diagnosed with both high-grade and low-grade gliomas. The primary objective was to assess the proficiency of nn-2D-IOUS in generating satisfactory image quality, identifying residual tumor tissue, and its influence on the extent of resection. To validate these results, early postoperative MRI data served as the reference standard. RESULTS: The nn-2D-IOUS exhibited a high level of effectiveness, successfully generating good quality images in 79% of the patients evaluated. With a sensitivity rate of 68% and a perfect specificity of 100%, nn-2D-IOUS unequivocally demonstrated its utility in intraoperative residual tumor detection. Notably, when total tumor removal was the surgical objective, a resection exceeding 95% of the initial tumor volume was achieved in 86% of patients. Additionally, patients in whom residual tumor was not detected by nn-2D-IOUS, the mean volume of undetected tumor tissue was remarkably minimal, averaging at 0.29 cm3. CONCLUSION: Our study supports nn-2D-IOUS's invaluable role in glioma surgery. The results highlight the utility of traditional technologies for enhanced surgical outcomes, even when compared to advanced alternatives. This is particularly relevant for resource-constrained settings and emphasizes optimizing existing tools for efficient patient care. NCT05873946 - 24/05/2023 - Retrospectively registered.

Reappraisal of the types of hypoglossal canal: endocranial approach.

This study aims to classify the endocranial variations inside the Hypoglossal Canal (HC) and evaluate the elements of the HC region in terms of sizes, diameters, and distances to the nearby surgical landmarks. The present study was done on 18 adult human fixed cadaver heads bilaterally. The internal opening of HC was examined for the presence of dural or osseos septations in the canal and was classified into five types (Type 1-5). The dimensions of hypoglossal nerve (CN XII) and the distance of intracranial openings of HC from the jugular foramen and jugular tubercle were measured. The prevalence of endocranial HC types were determined on both sides as follows: type 1 (23.53% left, 6.25% right), type 2 (37.5% right, 5.88% left), type 3 (52.94% left, 25% right), type 4 (18.75% right, 17.65% left), type 5 (12.5% right). Understanding the endocranial HC types is crucial for neurosurgeons in the differential diagnosis of various intracranial pathologies for the posterior cranial fossa approach. Knowing the anatomical relationships between the adjacent structures and symmetrical organization of the HC according to the types is crucial in determining surgical strategies and preserving adjacent structures.

Application of Intraoperative Contrast-Enhanced Ultrasound in the Resection of Brain Tumors.

OBJECTIVE: To investigate the value of routine intraoperative ultrasound (IU) and intraoperative contrast-enhanced ultrasound (ICEUS) in the surgical treatment of brain tumors, and to explore the utilization of ICEUS for the removal of the remnants surrounding the resection cavity. METHODS: In total, 51 patients who underwent operations from 2012 to 2018 due to different tumors in the brain were included in this study. The clinical data were evaluated retrospectively. IU was performed in all patients, among which 28 patients underwent ICEUS. The effects of IU and ICEUS on tumor resection and recurrence were evaluated. Semiquantitative analysis was performed to compare ICEUS parameters of the brain tumor with those of the surrounding tissue. RESULTS: In total, 36 male and 15 female patients were included in this study. The average age was 43 years (range: 14-68 years). The follow-up period was from 7 to 74 months (mean follow-up 32 months). IU was used in all patients, and no lesion was missed. Among them, 28 patients underwent ICEUS. The rate of total removal of the ICEUS group (23/28, 82%) was significantly higher than that of the IU group (11/23, 48%) (P<0.05). The recurrence rate of ICEUS and IU was 18% (5/23), and 22% (5/28), respectively, and the difference did not reach statistical significance (P>0.05). The semiquantitative analysis showed that the intensity and the transit time of microbubbles reaching the lesions were significantly different from the intensity and the transit time of microbubbles reaching the surrounding tissue (P<0.05) and reflected indirectly the volume and the speed of blood perfusion in the lesions was higher than those in the surrounding tissue. CONCLUSION: ICEUS is a useful tool in localizing and outlining brain lesions, especially for the resection of the hypervascular lesions in the brain. ICEUS could be more beneficial for identifying the remnants and improving the rate of total removal of these lesions than routine intraoperative ultrasound.

Acute cerebral venous outflow obstruction during convexity meningioma resection.

BACKGROUND: Cerebral venous outflow obstruction involves idiopathic intracranial hypertension, and the most common related condition is dural venous sinus stenosis or, in other words, an obstruction of the dural venous sinuses. In these cases, the pathological process is often chronic, displays only mild symptoms, and rarely requires urgent surgical intervention. In this study, we present a unique case involving an acute cerebral venous outflow obstruction that occurred during meningioma resection that ultimately had catastrophic consequences. MATERIALS AND METHODS: The patient's preoperative imaging only revealed an unremarkable frontal convexity meningioma with an average diameter exceeding 8 cm. She was admitted for a scheduled right frontoparietal craniotomy for lesion resection. RESULTS: The patient's unique congenital dural venous sinus structure along with a non-surgical epidural hematoma both contributed to a catastrophic outcome, causing a progressive hemispheric encephalocele, significant blood loss, and wound closure difficulties. CONCLUSION: Neurosurgeons should place an additional focus on cerebral venous outflow patency during tumor resection, even if the tumor does not involve the transverse or sigmoid sinuses. It is well known that the tacking sutures play an essential role in preventing an epidural hematoma, but the procedure to mitigate hematomas occurring outside the surgical field of view is not fully recognized by neurosurgeons. If dural tacking sutures are placed after complete tumor resection, the prophylactic effect for preventing EDH in the non-surgical areas may not be guaranteed. Therefore, we strongly advocate for the tacking sutures to be accurately placed before dural incisions are made.

[Endoscopic endonasal surgery during COVID-19 pandemic: Management guideline]. / Cirugía endoscópica endonasal durante la pandemia COVID-19: protocolo de actuación.

Current SARS-CoV-2 coronavirus pandemic is challenging medical and surgical activities. Specifically, within neurosurgery, endoscopic endonasal approaches pose a high risk of contagion for healthcare personnel involved in it. Initially, the recommendation was to avoid such surgeries. However, the pandemic has dragged on and new solutions must be proposed to continue carrying out these approaches safely. Given the lack of established protocols, we propose the following one, which concisely establishes the measures to be taken in both urgent and scheduled surgery. In addition, a new protection-aspiration device (Maskpirator) is described.

Applicability of contemporary quality indicators in vestibular surgery-do they accurately measure tumor inherent postoperative complications of vestibular schwannomas?

BACKGROUND: Due to rising costs in health care delivery, reimbursement decisions have progressively been based on quality measures. Such quality indicators have been developed for neurosurgical procedures, collectively. We aimed to evaluate their applicability in patients that underwent surgery for vestibular schwannoma and to identify potential new disease-specific quality indicators. METHODS: One hundred and three patients operated due to vestibular schwannoma were subject to analysis. The primary outcomes of interest were 30-day and 90-day reoperation, readmission, mortality, nosocomial infection and surgical site infection (SSI) rates, postoperative cerebral spinal fluid (CSF) leak, facial, and hearing function. The secondary aim was the identification of prognostic factors for the mentioned primary outcomes. RESULTS: Thirty-day (90-days) outcomes in terms of reoperation were 10.7% (14.6%), readmission 9.7% (13.6%), mortality 1% (1%), nosocomial infection 5.8%, and SSI 1% (1%). A 30- versus 90-day outcome in terms of CSF leak were 6.8% vs. 10.7%, new facial nerve palsy 16.5% vs. 6.1%. Hearing impairment from serviceable to non-serviceable hearing was 6.8% at both 30- and 90-day outcome. The degree of tumor extension has a significant impact on reoperation (p < 0.001), infection (p = 0.015), postoperative hemorrhage (p < 0.001), and postoperative hearing loss (p = 0.026). CONCLUSIONS: Our data demonstrate the importance of entity-specific quality measurements being applied even after 30 days. We identified the occurrence of a CSF leak within 90 days postoperatively, new persistent facial nerve palsy still present 90 days postoperatively, and persisting postoperative hearing impairment to non-serviceable hearing as potential new quality measurement variables for patients undergoing surgery for vestibular schwannoma.

Factors impacting surgical decision making between prenatal and postnatal repair for myelomeningocele.

OBJECTIVES: To determine factors influencing patients to choose prenatal or postnatal repair of their child's myelomeningocele (MMC) when both treatment options are offered. METHODS: We distributed a retrospective survey via email and social media to parents of children with MMC who were offered both prenatal and postnatal surgery as intervention options. RESULTS: A total of 127 surveys met all inclusion criteria. The majority of responders considered partner's opinion (85%), maternal risks of prenatal surgery (71%), and risk for preterm labor (76%) as influencers. Financially, the costs of childcare (39.4% postnatal, 13.8% prenatal, p = 0.002), relocation (57.6% postnatal, 36.2% prenatal, p = 0.019), and travel (51.5% postnatal, 33% prenatal, p = 0.033) were more influential for the postnatal group while insurance coverage (36.4% postnatal, 68.1% prenatal, p = 0.003) was more influential to the prenatal group. Of the medical factors, the consideration of maternal risk for transfusion was different between surgical groups (39.4% postnatal, 18.1% prenatal, p = 0.015). The open responses suggest that both surgical groups found the quality of life for the baby to be significant to their decision-making. CONCLUSIONS: These findings should guide providers to tailor counseling to patient's needs. Comprehensive counseling should include information on financial resources, referral to financial counselors, and psychosocial support services.

Analysis of neurosurgical procedures with unplanned reoperation for quality improvement: A 5-year single hospital study.

ABSTRACT: The unplanned return to the operating room rate is a quality metric for assessing hospital performance. This study aimed to evaluate the cause, incidence, and time interval of unplanned returns in index neurosurgical procedures within 30 days of the initial surgery as an internal audit. We retrospectively analyzed neurosurgical procedures between January 2015, and December 2019, in a single regional hospital. The definition of an unplanned return to the operating room was a patient who underwent two operations within 30 days when the second procedure was not planned, staged, or related to the natural course of the disease.A total of 4365 patients were identified in our analysis, of which 93 (2%) had an unplanned return to the operating room within 30 days of their initial surgery during admission. The most common reason for an unplanned return to the operating room for a cranial procedure was hemorrhage, followed by hydrocephalus and subdural effusion, which accounted for 49.5%(46/93), 12%(11/93), and 5.4%(5/93) of cases, respectively. In spinal procedures, the most common cause of return was a residual disc, followed by surgical site infection, which accounted for 5.4%(5/93) and 4.3%(4/93) of cases, respectively. The overall median time interval for unplanned returns to the operating room was 3 days (interquartile range, 1-9).Lowering the rate of postoperative hemorrhage in cranial surgery and postoperative residual disc in spine surgery was crucial as an internal audit in a 5-year single institute follow-up. However, the unplanned reoperation rate is less helpful in benchmarking because of the heterogeneity of patients between hospitals.

First American College of Surgeons National Surgical Quality Improvement Program Report from a Low-Middle-Income Country: A 1-Year Outcome Analysis of Neurosurgical Cases.

BACKGROUND: Low-middle-income countries (LMICs) share a substantial proportion of global surgical complications. This is compounded by the seemingly deficient documentation of postsurgical complications and the lack of a national average for comparison. In this context, the implementation of the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) that compares hospital performance based on postsurgical complication data provided by a wide array of centers, could be a major initiative in a resource-challenged setting. Implementation of the NSQIP has provenly mitigated postoperative morbidity and mortality across many centers all over the world. To our knowledge, this report is the first from an LMIC to report its postoperative neurosurgical complications in comparison with international benchmarks. METHODS: Our hospital joined the NSQIP in 2019. Through a standardized ACS protocol, ACS-trained surgical clinical reviewers (SCRs) reviewed and extracted data from randomly assigned neurosurgical patients' medical records from preoperative to postoperative (30-day) data using validated, standardized data definitions. SCRs entered deidentified data in an online Health Insurance Portability and Accountability Act web-based secure platform. The validated data were then consigned to the ACS NSQIP head office in the United States where the data were analyzed and compared with similar data from other centers registered with the NSQIP. In this way, our hospital was rated for each of the variables related to postsurgical complications after both spinal and cranial procedures, and the results were sent back to us in the form of text, tables, and graphs. RESULTS: Our initial report suggested a relatively higher odds ratio for sepsis and readmissions after spinal procedures at our hospital, and a similarly higher odds ratio for morbidity, sepsis, urinary tract infection, and surgical site infection for cranial procedures. For these variables, our hospital fell in the needs improvement category of the NSQIP. For the rest of the variables studied for both spinal and cranial procedures, the hospital fell in the as expected category of the NSQIP. CONCLUSIONS: Implementation of the NSQIP is an important first step in creating a culture of transparency, safety, and quality. This is the first report of NSQIP implementation in an LMIC, and we have shown comparable results to developed countries.

Standardizing postoperative care for pediatric intradural Chiari decompressions to decrease length of stay.

OBJECTIVE: Amid national and local budget crises, cutting costs while maintaining quality care is a top priority. Chiari malformation is a relatively common pediatric neurosurgical pathology, and postoperative care varies widely. The postoperative course can be complicated by pain and nausea, which can extend the hospital stay. In this study, the authors aimed to examine whether instituting a standardized postoperative care protocol would decrease overall patient hospital length of stay (LOS) as well as cost to families and the hospital system. METHODS: A retrospective study of pediatric patients who underwent an intradural Chiari decompression with expansile duraplasty at a single institution from January 2016 to September 2019 was performed. A standardized postoperative care protocol was instituted on May 17, 2018. Pre- and postprotocol groups were primarily analyzed for demographics, LOS, and the estimated financial expense of the hospital stay. Secondary analysis included readmissions, opioid consumption, and follow-up. RESULTS: The analysis included 132 pediatric patients who underwent an intradural Chiari decompression with expansile duraplasty. The preprotocol group included 97 patients and the postprotocol group included 35 patients. Patient age ranged from 0.5 to 26 years (mean 9.5 years). The mean LOS preprotocol was 55.48 hours (range 25.90-127.77 hours), and the mean postprotocol LOS was 46.39 hours (range 27.58-77.38 hours). The comparison between means showed a statistically significant decrease following protocol initiation (95% CI 1.87-16.31 hours, p = 0.014). In the preprotocol group, 21 of 97 patients (22%) were discharged the first day after surgery compared with 14 of 35 patients (40%) in the postprotocol group (p = 0.045). The estimated cost of one night on the pediatric neurosurgical intermediate ward was approximately $4500, which gives overall cost estimates for 100 theoretical cases of $927,800 for the preprotocol group and $732,900 for the postprotocol group. CONCLUSIONS: By instituting a Chiari protocol, postoperative LOS was significantly decreased, which resulted in decreased healthcare costs while maintaining high-quality and safe care.

Teamwork in Cranial Base Surgery: A Feasible Task or a Utopian Dream.

In the past decade or perhaps a little earlier than that the concept of teamwork evolved among the circles of surgeons especially among those involved in complicated and time consuming surgeries. Skull base surgeries were one of those surgeries where the role of teamwork was acutely felt owing to innumerable specialties involved in the consummation of such surgeries. Although teamwork in this specialty is the need of the hour but, achieving the spirit of teamwork is not that easy and perhaps a challenging task. This manuscript tackles the much needed demand of teamwork in this arena of surgery and unveils whether such a teamwork is achievable or is just an utopian dream.

Advances in Epilepsy Surgery.

BACKGROUND: A large number of patients have epilepsy that is intractable and adversely affects a child's lifelong experience with addition societal burden that is disabling and expensive. The last two decades have seen a major explosion of new antiseizure medication options. Despite these advances, children with epilepsy continue to have intractable seizures. An option that has been long available but little used is epilepsy surgery to control intractable epilepsy. METHODS: This article is a review of the literature as well as published opinions. RESULTS: Epilepsy surgery in pediatrics is an underused modality to effectively treat children with epilepsy. Adverse effects of medication should be weighed against risks of surgery as well as risks of nonefficacy. CONCLUSIONS: We discuss an approach to selecting the appropriate pediatric patient for consideration, a detailed evaluation including necessary evaluation, and the creation of an algorithm to approach patients with both generalized and focal epilepsy. We then discuss surgical options available including outcome data. New modalities are also addressed including high-frequency ultrasound and co-registration techniques including magnetic resonance imaging-guided laser therapy.

Location of Traumatic Cranial Epidural Hematoma Correlates with the Source of Hemorrhage: A 12-Year Surgical Review.

BACKGROUND: Epidural hematoma (EDH) can result in a catastrophic outcome of traumatic brain injury. Current management guidelines do not consider the source of hemorrhage in decision making. The purpose of this study was to examine the relationship between EDH location and the source of hemorrhage. METHODS: We report retrospectively reviewed, prospectively obtained surgical data of patients with acute traumatic cranial EDH treated between 2007 and 2018. Computed tomography (CT) scans were used to categorize EDH location as lateral or medial. The source of hemorrhage was identified intraoperatively by a single surgeon. RESULTS: Overall, of 92 evacuated EDHs (in 87 patients), 71 (77.2%) were in the lateral location. Arterial bleeding was the cause of EDH in 63.4% of the lateral EDHs and 9.2% of the medial EDHs (P < 0.0001). In the cases where surgery was done primarily to treat EDH, 65.3% had an arterial bleed source (P < 0.0001). In those treated for primary reasons other than EDH evacuation, 75% had a venous bleed source (P = 0.002). CONCLUSIONS: The location of EDH correlates with the source of hemorrhage. The decision to operate on EDH may be influenced by this factor.

Fetoscopic myelomeningocoele closure: Is the scientific evidence enough to challenge the gold standard for prenatal surgery?

Since the completion of the Management of Myelomeningocoele Study, maternal-fetal surgery for spina bifida has become a valid option for expecting parents. More recently, multiple groups are exploring a minimally invasive approach and recent outcomes have addressed many of the initial concerns with this approach. Based on a previously published framework, we attempt to delineate the developmental stage of the surgical techniques. Furthermore, we discuss the barriers of performing randomized controlled trials comparing two surgical interventions and suggest that data collection through registries is an alternative method to gather high-grade evidence.