Rib Mediated Non-Cardiac Chest Pain: A Case Report.

Non-cardiac chest pain (NCCP) is a very common and functionally limiting pain complaint that vexes patients and medical providers leading to time-consuming and expensive diagnostic work-ups as well as significant disability and lost productivity. Despite extensive debate and research, there is no definitive treatment recommendation or high-level evidence to support a conservative care treatment approach, or interventional management procedures for the diagnosis and alleviation of NCCP. In patients presenting with chest pain, after ruling out life-threatening causes, the diagnosis of NCCP is made. This process is a diagnosis of exclusion rather than a specific etiology with a defined treatment plan. This results in specialty consultation, advanced diagnostic testing, and delayed definitive care. A better triage process may include the incorporation of diagnostic maneuvers at the primary care and emergency room to justify referral to a musculoskeletal specialist in lieu of or during advanced diagnostic work-up. After the diagnosis of NCCP is made in our young and active patient population, we have seen significant success in the application of manipulation and a functional restoration program similar to the presented case. To our knowledge, this treatment approach has not been previously described. While this management strategy may be taught in physiotherapy courses, we provide the case to illustrate a multimodal treatment approach that seems to be unknown or underutilized based on the number of referrals and prevalence of this condition.

Evaluation and Management of Sacroiliac Dysfunction Utilizing an Evidence-Based Algorithmic Approach: A Case Study.

The sacroiliac joint (SIJ) is an important contributor to persistent and functionally limiting lower back pain. Despite extensive debate and research, there is no definitive treatment recommendation or high-level evidence to support a conservative care treatment approach, nor interventional or surgical management procedures for the alleviation of pain originating from the SIJ. Traditional physical therapy and conservative approaches to generalized lower back pain often fail in this patient subset prompting sub-specialty consultation to a pain management center. Diagnosis of the SIJ as the pain generator can be accomplished through physical exam maneuvers and comparative diagnostic blocks; however, upon diagnosis, management remains a challenge. After the diagnosis of SIJ dysfunction is made in our young and active patient population, we have seen significant success in the application of an interdisciplinary and evidence-based treatment algorithm similar to the presented case. To our knowledge, this treatment approach has not been previously described.

Cryoablation of the Infrapatellar Branch of the Saphenous Nerve Identified by Non-Invasive Peripheral Nerve Stimulator for the Treatment of Non-Surgical Anterior Knee Pain: A Case Series and Review of the Literature.

Chronic, non-surgical, non-specific anterior knee pain is a common source of functionally limiting chronic ailment, especially in a young athletic and active-duty military population. The infrapatellar branch of the saphenous is becoming a common therapeutic target for the diagnosis and treatment of anterior knee pain. It is a nerve commonly injured during knee surgeries and trauma, resulting in neuroma formation and chronic neuropathic pain states, and it can also transmit nociceptive input from patients with non-surgical anterior knee pain of multiple etiologies. Several methods have been employed to treat this condition. After the diagnosis of infrapatellar saphenous neuralgia, the nerve is safely ablated using radiofrequency ablation, neurolytic solutions, and, most recently, cryoablation using the handheld iovera® cryoablation system (Myoscience, Inc. Fremont, CA). Cryoablation is an attractive technique because it is minimally invasive, not permanent, and well tolerated by the patient with only local anesthesia. We have previously described a technique using a non-invasive peripheral nerve stimulator to identify and treat the exact location of the nerve more precisely, thereby optimizing treatment success and procedural simplicity. This case series illustrates our initial use and success with this technique. Further follow-up and randomized sham-controlled trials are also planned.

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group.

BACKGROUND: The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial. METHODS: After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached. RESULTS: 17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary). CONCLUSIONS: Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Pain Management Best Practices from Multispecialty Organizations During the COVID-19 Pandemic and Public Health Crises.

BACKGROUND: It is nearly impossible to overestimate the burden of chronic pain, which is associated with enormous personal and socioeconomic costs. Chronic pain is the leading cause of disability in the world, is associated with multiple psychiatric comorbidities, and has been causally linked to the opioid crisis. Access to pain treatment has been called a fundamental human right by numerous organizations. The current COVID-19 pandemic has strained medical resources, creating a dilemma for physicians charged with the responsibility to limit spread of the contagion and to treat the patients they are entrusted to care for. METHODS: To address these issues, an expert panel was convened that included pain management experts from the military, Veterans Health Administration, and academia. Endorsement from stakeholder societies was sought upon completion of the document within a one-week period. RESULTS: In these guidelines, we provide a framework for pain practitioners and institutions to balance the often-conflicting goals of risk mitigation for health care providers, risk mitigation for patients, conservation of resources, and access to pain management services. Specific issues discussed include general and intervention-specific risk mitigation, patient flow issues and staffing plans, telemedicine options, triaging recommendations, strategies to reduce psychological sequelae in health care providers, and resource utilization. CONCLUSIONS: The COVID-19 public health crisis has strained health care systems, creating a conundrum for patients, pain medicine practitioners, hospital leaders, and regulatory officials. Although this document provides a framework for pain management services, systems-wide and individual decisions must take into account clinical considerations, regional health conditions, government and hospital directives, resource availability, and the welfare of health care providers.

Effect of Stellate Ganglion Block Treatment on Posttraumatic Stress Disorder Symptoms: A Randomized Clinical Trial.

Importance: This is the first multisite, randomized clinical trial of stellate ganglion block (SGB) outcomes on posttraumatic stress disorder (PTSD) symptoms. Objective: To determine whether paired SGB treatments at 0 and 2 weeks would result in improvement in mean Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) total symptom severity scores from baseline to 8 weeks. Design, Setting, and Participants: This multisite, blinded, sham-procedure, randomized clinical trial used a 2:1 SGB:sham ratio and was conducted from May 2016 through March 2018 in 3 US Army Interdisciplinary Pain Management Centers. Only physicians performing the procedures and the procedure nurses were aware of the intervention (but not the participants or assessors); their interactions with the participants were scripted and limited to the 2 interventions. Active-duty service members on stable psychotropic medication dosages who had a PTSD Checklist-Civilian Version (PCL-C) score of 32 or more at screening were included. Key exclusion criteria included a prior SGB treatment, selected psychiatric disorders or substance use disorders, moderate or severe traumatic brain injury, or suicidal ideation in the prior 2 months. Interventions: Paired right-sided SGB or sham procedures at weeks 0 and 2. Main Outcomes and Measures: Improvement of 10 or more points on mean CAPS-5 total symptom severity scores from baseline to 8 weeks, adjusted for site and baseline total symptom severity scores (planned a priori). Results: Of 190 screened individuals, 113 (59.5%; 100 male and 13 female participants; mean [SD] age, 37.3 [6.7] years) were eligible and randomized (74 to SGB and 39 to sham treatment), and 108 (95.6% of 113) completed the study. Baseline characteristics were similar in the SGB and sham treatment groups, with mean (SD) CAPS-5 scores of 37.6 (11.2) and 39.8 (14.4), respectively (on a scale of 0-80); 91 (80.0%) met CAPS-5 PTSD criteria. In an intent-to-treat analysis, adjusted mean total symptom severity score change was -12.6 points (95% CI, -15.5 to -9.7 points) for the group receiving SGB treatments, compared with -6.1 points (95% CI, -9.8 to -2.3 points) for those receiving sham treatment (P = .01). Conclusions and Relevance: In this trial of active-duty service members with PTSD symptoms (at a clinical threshold and subthreshold), 2 SGB treatments 2 weeks apart were effective in reducing CAPS-5 total symptom severity scores over 8 weeks. The mild-moderate baseline level of PTSD symptom severity and short follow-up time limit the generalizability of these findings, but the study suggests that SGB merits further trials as a PTSD treatment adjunct. Trial Registration: ClinicalTrials.gov identifier: NCT03077919.

Identification of the Infrapatellar Branch of the Saphenous Nerve for Treatment Using a Peripheral Nerve Stimulator: A Technical Report.

The infrapatellar branch of the saphenous is becoming a common therapeutic target for the diagnosis and treatment of anterior knee pain. It is a nerve commonly injured during knee surgeries, resulting in neuroma formation and chronic neuropathic pain states, and can also transmit nociceptive input in patients with non-surgical anterior knee pain of multiple etiologies. After diagnosing infrapatellar saphenous neuralgia, the nerve is safely ablated using radiofrequency ablation, neurolytic solutions, and, most recently, cryoablation using the handheld iovera® cryoablation system (Myoscience, Inc. Fremont, CA). The iovera® technology benefits from procedural simplicity in that the nerve doesn't specifically need to be identified and the described technique involves treating a long line over which the infrapatellar branch of the saphenous nerve is expected to course. However, there is significant variability in the course of the nerve and much of the area treated misses the actual location of the nerve, wasting time and potentially increasing patient discomfort and risk of complications. To address these limitations we endeavored to identify a way to more precisely treat the specific location of the nerve thereby optimizing treatment success and procedural simplicity. Using a MiniStim® peripheral nerve stimulator (Halyard Health, Inc., Georgia, US) to scan for the nerve along the previously described treatment line, we have been able to identify a more precise location of the nerve and optimize the treatment target area. This non-invasive identification technique has, to our knowledge, not been previously described.

Safety and Patient Acceptability of Stellate Ganglion Blockade as a Treatment Adjunct for Combat-Related Post-Traumatic Stress Disorder: A Quality Assurance Initiative.

OBJECTIVE:  To perform a quality assurance and performance improvement project through review of our single center data on the safety and patient acceptability of the stellate ganglion blockade (SGB) procedure for the relief of symptoms related to chronic post-traumatic stress disorder. BACKGROUND:  Our interventional pain management service has been offering trials of SGB therapy to assist with the management of the sympathetically mediated anxiety and hyperarousal symptoms of severe and treatment-refractory combat-related PTSD. There have been multiple case series in the literature describing the potential impact of this procedure for PTSD symptom management as well as the safety of image-guided procedures. We wished to ensure that we were performing this procedure safely and that patients were tolerating and accepting of this adjunctive treatment option. METHODS:  We conducted a review of our quality assurance and performance improvement data over the past 18 months during which we performed 250 stellate ganglion blocks for the management of PTSD symptoms to detect any potential complications or unanticipated side effects.  We also analyzed responses from an anonymous patient de-identified survey collected regarding the comfort and satisfaction associated with the procedure. RESULTS:  We did not identify any immediate post-procedural complications or delayed complications from any of the 250 procedures performed from November 2013 to April 2015. Of the 110 surveys that were returned and tabulated, 100% of the patients surveyed were overall satisfied with our process and with the procedure, 100% said they would recommend the procedure to a friend, and 95% stated that they would be willing to undergo as many repeat procedures as necessary based on little discomfort and tolerable side effects. CONCLUSION:  Our quality assurance assessment suggests that in our center the SGB procedure for PTSD is a safe, well-tolerated, and acceptable treatment adjunct in the management of severe symptoms associated with chronic treatment-refractory PTSD. Patient satisfaction responses are strongly suggestive of high therapeutic value, and further studies are indicated to determine the effectiveness, duration of action, and optimal treatment regimen.

Randomized, double-blind, comparative-effectiveness study comparing pulsed radiofrequency to steroid injections for occipital neuralgia or migraine with occipital nerve tenderness.

Occipital neuralgia (ON) is characterized by lancinating pain and tenderness overlying the occipital nerves. Both steroid injections and pulsed radiofrequency (PRF) are used to treat ON, but few clinical trials have evaluated efficacy, and no study has compared treatments. We performed a multicenter, randomized, double-blind, comparative-effectiveness study in 81 participants with ON or migraine with occipital nerve tenderness whose aim was to determine which treatment is superior. Forty-two participants were randomized to receive local anesthetic and saline, and three 120 second cycles of PRF per targeted nerve, and 39 were randomized to receive local anesthetic mixed with deposteroid and 3 rounds of sham PRF. Patients, treating physicians, and evaluators were blinded to interventions. The PRF group experienced a greater reduction in the primary outcome measure, average occipital pain at 6 weeks (mean change from baseline -2.743 ± 2.487 vs -1.377 ± 1.970; P < 0.001), than the steroid group, which persisted through the 6-month follow-up. Comparable benefits favoring PRF were obtained for worst occipital pain through 3 months (mean change from baseline -1.925 ± 3.204 vs -0.541 ± 2.644; P = 0.043), and average overall headache pain through 6 weeks (mean change from baseline -2.738 ± 2.753 vs -1.120 ± 2.1; P = 0.037). Adverse events were similar between groups, and few significant differences were noted for nonpain outcomes. We conclude that although PRF can provide greater pain relief for ON and migraine with occipital nerve tenderness than steroid injections, the superior analgesia may not be accompanied by comparable improvement on other outcome measures.

Efficacy of stellate ganglion block in the treatment of anxiety symptoms from combat-related post-traumatic stress disorder: a case series.

OBJECTIVE: Report the efficacious use of stellate ganglion blocks (SGBs) in treating the anxiety symptoms of four patients diagnosed with combat-related post-traumatic stress disorder (PTSD) and discuss possible mechanisms of action to explain these findings. BACKGROUND: Successful treatment of PTSD with SGB has been demonstrated and reported previously at Walter Reed Army Medical Center. An identical protocol was used at Tripler Army Medical Center to treat four service members diagnosed with combat-related PTSD. METHODS: All patients reported received an SGB on the right side at the level of C6. The patient's PTSD symptoms were evaluated using the Post-traumatic Stress Disorder Checklist (PCL). This checklist was distributed one day before treatment and again the day following treatment. The patients were also given the PCL at subsequent follow-up visits to quantify sustained benefit. RESULTS: SGB showed acute benefit for the symptoms of PTSD by markedly reduced PCL scores after the procedure. Benefits were also sustained during close outpatient follow-up. CONCLUSION: Selective blockade of the right stellate ganglion at C6 is a minimally invasive procedure with an excellent safety profile that may provide sustained relief of PTSD symptoms. The procedure may also provide benefit for those who are resistant to psychotropic intervention.

Does difficult mask ventilation predict obstructive sleep apnea? A prospective pilot study to identify the prevalence of osa in patients with difficult mask ventilation under general anesthesia.

BACKGROUND: Given the pathogenesis of obstructive sleep apnea (OSA), anesthesiologists may be in a unique position to rapidly identify patients who are at risk for undiagnosed OSA in the perioperative period. Identification is the first step in prompt diagnosis and potential prevention of OSA related comorbidities. Patients who exhibit unanticipated difficult mask ventilation (DMV) during induction of general anesthesia may be at risk of having undiagnosed OSA. OBJECTIVE: To determine the association of OSA in patients with difficult mask ventilation under general anesthesia. METHODS: Ten patients were identified over a 2-year period at the time of anesthetic induction as being difficult to mask ventilate and were then enrolled in this prospective pilot study. After enrollment and informed consent, the patients were referred to the sleep study center for full overnight polysomnography to evaluate for the presence and severity of OSA. RESULTS: Of our cohort, 9/10 patients exhibited polysomnographic evidence of OSA, while the last subject tested positive for sleep disordered breathing. Eighty percent (8/10) of subjects espoused snoring, but only 10% (1/10) reported witnessed apneas. Average DMV was 2.5, and higher grades of DMV were associated with more severe OSA. CONCLUSION: In this study, difficult mask ventilation was predictive of undiagnosed OSA. Anesthesiologists may be in a unique position to identify patients at risk for OSA and prevention of related comorbidities.

The use of stellate ganglion block in the treatment of panic/anxiety symptoms with combat-related post-traumatic stress disorder; preliminary results of long-term follow-up: a case series.

OBJECTIVE: Report the successful use of stellate ganglion blocks (SGBs) in two patients experiencing symptoms of post-traumatic stress disorder (PTSD). BACKGROUND: Successful treatment of PTSD with SGB has been reported previously. A similar protocol was employed at Walter Reed Army Medical Center to treat two soldiers with chronic, combat-related PTSD. METHODS: Both patients received a SGB on the right side at C6 level. The patients' PTSD symptoms were evaluated using the Post-traumatic Stress Disorder Checklist (PCL). The PCL was administered the day prior to treatment, to establish a baseline, and the day after treatment. The PCL was also utilized during follow-up visits to quantify the patient's symptomotology. The SGB was administered by an anesthesiologist and the psychometric tests administered by a psychologist. RESULTS: Both patients experienced immediate, significant and durable relief as measured by the PCL (score minimum 17, maximum 85). In both instances, the pre-treatment score suggested a PTSD diagnosis whereas the post-treatment scores did not. One patient requested repeat treatment after 3 months, and the post-treatment score remained below the PTSD cutoff after 7 additional months of follow-up. Both patients discontinued all antidepressant and antipsychotic medications while maintaining their improved PCL score. CONCLUSION: Selective blockade of the right stellate ganglion at C6 level is a safe and minimally invasive procedure that may provide durable relief from PTSD symptoms, allowing the safe discontinuation of psychiatric medications. blacksquare, square, filled.

Randomized study assessing the accuracy of cervical facet joint nerve (medial branch) blocks using different injectate volumes.

BACKGROUND: Neck pain is a frequent cause of disability, with facet joint arthropathy accounting for a large percentage of cases. The diagnosis of cervical facet joint pain is usually made with diagnostic blocks of the nerves that innervate them. Yet, medial branch blocks are associated with a high false-positive rate. One hypothesized cause of inaccurate diagnostic blocks is inadvertent extravasation of injectate into adjacent pain-generating structures. The objective of this study was to evaluate the accuracy of medial branch blocks by using different injectate volumes. METHODS: Twenty-four patients received cervical medial branch blocks, using either 0.5 or 0.25 ml of bupivacaine mixed with contrast. One half of the patients in each group were suballocated to receive the blocks in the prone position and the other half through a lateral approach. Participants then underwent computed tomography of the cervical spine to evaluate accuracy and patterns of aberrant contrast spread. RESULTS: Sixteen instances of aberrant spread were observed in nine patients receiving blocks using 0.5 ml versus seven occurrences in six patients in the 0.25 ml group (P = 0.07). Aberrant spread was most commonly observed (57%) when an injection at C3 engulfed the third occipital nerve. Among the 86 nerve blocks, foraminal spread occurred in five instances using 0.5 ml and in two cases with 0.25 ml. The six "missed" nerves were equally divided between treatment groups. No significant difference in any outcome measure was observed between the prone and lateral positions. CONCLUSIONS: Reducing the volume during cervical medial branch blocks may improve precision and accuracy.

Back pain during war: an analysis of factors affecting outcome.

BACKGROUND: Back pain is the leading cause of disability in the world, but it is even more common in soldiers deployed for combat operations. Aside from battle injuries and psychiatric conditions, spine pain and other musculoskeletal conditions are associated with the lowest return-to-unit rate among service members medically evacuated out of Operations Iraqi and Enduring Freedom. METHODS: Demographic, military-specific, and outcome data were prospectively collected over a 2-week period at the Deployed Warrior Medical Management Center in Germany on 1410 consecutive soldiers medically evacuated out of theaters of combat operations for a primary diagnosis pertaining to back pain between 2004 and 2007. The 2-week period represents the maximal allowable time an evacuated soldier can spend in treatment before disposition (ie, return to theater or evacuate to United States) is rendered. Electronic medical records were then reviewed to examine the effect a host of demographic and clinical variables had on the categorical outcome measure, return to unit. RESULTS: The overall return-to-unit rate was 13%. Factors associated with a positive outcome included female sex, deployment to Afghanistan, being an officer, and a history of back pain. Trends toward not returning to duty were found for navy and marine service members, coexisting psychiatric morbidity, and not being seen in a pain clinic. CONCLUSIONS: The likelihood of a service member medically evacuated out of theater with back pain returning to duty is low irrespective of any intervention(s) or characteristic(s). More research is needed to determine whether concomitant treatment of coexisting psychological factors and early treatment "in theater" can reduce attrition rates.

A unique presentation of complex regional pain syndrome type I treated with a continuous sciatic peripheral nerve block and parenteral ketamine infusion: a case report.

OBJECTIVE: To successfully treat a patient with complex regional pain syndrome, refractory to standard therapy, to enable a rapid and full return to professional duties. SETTING: This case report describes the rapid resolution of an unusual presentation of complex regional pain syndrome type I after four days of treatment with a continuous sciatic peripheral nerve block and a concomitant parenteral ketamine infusion. The patient was initially diagnosed with complex regional pain syndrome (CRPS) I of the right lower extremity following an ankle inversion injury. Oral medication with naproxen and gabapentin, as well as desensitization therapy, failed to provide any relief of her symptoms. She was referred to the interventional pain management clinic. A lumbar sympathetic block failed to provide any relief. The patient was diagnosed with CRPS I and was admitted for treatment with a continuous peripheral nerve block and parenteral ketamine. CONCLUSION: This case suggests therapeutic benefit from aggressive treatment of both the peripheral and central components of CRPS.

Opioid-free balanced anesthesia for cervical ganglionectomy subsequent to recent ultra rapid opioid detoxification.

OBJECTIVE: To perform an opioid-free, balanced anesthetic for an Active Duty soldier undergoing cervical ganglionectomy for intractable occipital neuralgia 7 days after ultra rapid opioid detoxification (UROD) under general anesthesia. SETTING: Opioids have been a mainstay for both intraoperative and postoperative analgesia. With the emergence of newer non-opioid analgesics and the practice of the multimodal analgesia, opioid therapy will be complimented and, in some cases, replaced by these newer agents. The increasing knowledge in the literature of both pain mechanisms and chronic pain treatment can present anesthesiologists with a challenge when faced with opioid-tolerant patients in the acute perioperative setting. With an increased focus on adequate pain control among health care regulatory agencies, we may expect to see a growing number of patients who desire weaning from chronic opioid therapy. There have been many weaning protocols proposed in the literature, with UROD under general anesthesia being one of them. We report a case of successful non-opioid analgesia in a patient that presented for a cervical ganglionectomy 7 days after UROD. CONCLUSIONS: This patient successfully completed a perioperative and postoperative course using ketamine and dexmedetomidine infusions, in addition to other non-opioid adjuncts. The patient returned to her Active Duty station, with increased functional capacity and remains opioid-free.

U.S.-Canada cooperation: the U.S.-Canada air quality agreement.

The impetus for the Canada-U.S. Air Quality Agreement was transboundary acid rain in eastern North America. This problem drove the parties to develop a bilateral agreement that not only addressed this issue, but also set up a broad and flexible framework to address other air quality problems. In 2000, the Ozone Annex to reduce smog and its precursor pollutants was negotiated. A transboundary particulate matter (PM) science assessment in 2004 led to the commencement of negotiation of a PM annex in late 2007. Over the course of 15 yr, Canada and the United States also developed innovative cooperative arrangements. Two transboundary airshed dialogues became important sources of practical on-the-ground cooperation in the Georgia Basin-Puget Sound and the Great Lakes Basin. In addition to providing the basis for ongoing international dialogue, these transboundary airshed projects resulted in changes to administrative practices as the parties exchange information and learn from each other in ways that benefit the airshed community. The nature of the Air Quality Agreement also enabled both Canada and the United States to address concerns each has had about specific pollutant sources and to address them in ways that avoided confrontation and resulted in air quality improvements for people living in the airsheds. Case studies of three of the "informal consultations" that have occurred under the agreement are described: where discussions occurred around a power plant in Michigan, a power plant in Saskatchewan, and a steel mill in Ontario. More than an agreement, this relationship has built a capacity to deal with common problems. Fostering such a relationship with its implicit transfer of knowledge and experience has opened doors for discussions on a new Clean Air framework in Canada and joint analyses of cross-border sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions caps and trading. U.S. experience with cap and trading is highlighted for background and context. The flexibility inherent in the agreement provides a platform for future air quality issues and continued communication without borders.