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.

Establishing an optimal "cutoff" threshold for diagnostic lumbar facet blocks: a prospective correlational study.

OBJECTIVES: Diagnostic medial branch blocks (MBB) are considered the reference standard for diagnosing facetogenic pain and selecting patients for radiofrequency (RF) denervation. Great controversy exists regarding the ideal cutoff for designating a block as positive. The purpose of this study is to determine the optimal pain relief threshold for selecting patients for RF denervation after diagnostic MBB. METHODS: In this multicenter, prospective correlational study, 61 consecutive patients undergoing lumbar facet RF denervation after experiencing significant pain relief after MBB were enrolled. A positive outcome was defined as a ≥50% reduction in back pain at rest or with activity coupled with a positive satisfaction score lasting longer than 3 months. The relationship between pain relief after the blocks and denervation outcomes was evaluated by pairwise correlation matrix, receiver's operating characteristic curve, and stratifying outcomes based on 10- and 17-percentage point intervals for MBB. RESULTS: There were no significant differences in RF outcomes based on any MBB pain relief cutoff over 50%. A trend was noted whereby those patients who obtained <50% pain relief reported poorer outcomes. No optimal threshold for designating a diagnostic block as positive, above 50% pain relief, could be calculated. CONCLUSION: Employing more stringent selection criteria for lumbar facet RF is likely to result in withholding a beneficial procedure from a substantial number of patients, without improving success rates.

Epidural steroids, etanercept, or saline in subacute sciatica: a multicenter, randomized trial.

BACKGROUND: Perineural inhibitors of tumor necrosis factor have recently generated intense interest as an alternative to epidural steroid injections for lumbosacral radiculopathy. OBJECTIVE: To evaluate whether epidural steroids, etanercept, or saline better improves pain and function in adults with lumbosacral radiculopathy. DESIGN: A multicenter, 3-group, randomized, placebo-controlled trial conducted from 2008 to 2011. Randomization was computer-generated and stratified by site. Pharmacists prepared the syringes. Patients, treating physicians, and nurses assessing outcomes were blinded to treatment assignment. (ClinicalTrials.gov registration number: NCT00733096) SETTING: Military and civilian treatment centers. PATIENTS: 84 adults with lumbosacral radiculopathy of less than 6 months' duration. INTERVENTION: 2 epidural injections of steroids, etanercept, or saline, mixed with bupivacaine and separated by 2 weeks. MEASUREMENTS: The primary outcome measure was leg pain 1 month after the second injection. All patients had 1-month follow-up visits; patients whose condition improved remained blinded for the 6-month study period. RESULTS: The group that received epidural steroids had greater reductions in the primary outcome measure than those who received saline (mean difference, -1.26 [95% CI, -2.79 to 0.27]; P = 0.11) or etanercept (mean difference, -1.01 [CI, -2.60 to 0.58]; P = 0.21). For back pain, smaller differences favoring steroids compared with saline (mean difference, -0.52 [CI, -1.85 to 0.81]; P = 0.44) and etanercept (mean difference, -0.92 [CI,-2.28 to 0.44]; P = 0.18) were observed. The largest differences were noted for functional capacity, in which etanercept fared worse than the other treatments: steroids vs. etanercept (mean difference, -16.16 [CI, -26.05 to -6.27]; P = 0.002), steroids vs. saline (mean difference, -5.87 [CI, -15.59 to 3.85]; P = 0.23), and etanercept vs. saline (mean difference, 10.29 [CI, 0.55 to 20.04]; P = 0.04). More patients treated with epidural steroids (75%) reported 50% or greater leg pain relief and a positive global perceived effect at 1 month than those who received saline (50%) or etanercept (42%) (P = 0.09). LIMITATION: Short-term follow-up, small sample size, and a possibly subtherapeutic dose of etanercept. CONCLUSION: Epidural steroid injections may provide modest short-term pain relief for some adults with lumbosacral radiculopathy, but larger studies with longer follow-up are needed to confirm their benefits. PRIMARY FUNDING SOURCE: The John P. Murtha Neuroscience and Pain Institute, International Spinal Intervention Society, and Center for Rehabilitation Sciences Research.

Headaches during war: analysis of presentation, treatment, and factors associated with outcome.

BACKGROUND: Headache is often associated with physical trauma and psychological stress. The aim of this study is to evaluate the impact of headache on personnel deployed in war zones and to identify factors associated with return to duty (RTD). METHODS: Outcome data were prospectively collected on 985 personnel medically evacuated out of Operations Iraqi and Enduring Freedom for a primary diagnosis of headache between 2004 and 2009. Electronic medical records were reviewed to examine clinical and treatment patterns and the effect that myriad factors had on RTD. RESULTS: 33.6% of evacuees returned to duty. The most common headaches were post-concussion (34.1%) and migraine (30.0%). Headaches typically associated with trauma such as post-concussion (18.7%), occipital neuralgia (23.1%), and cervicogenic headache (29.7%) had the lowest RTD rates, whereas tension headache (49.6%) was associated with the best outcome. Other variables associated with negative outcome included presence of aura (OR 0.51, 95% CI 0.30-0.88; p = 0.02), traumatic brain injury (OR 0.50, 95% CI 0.29-0.87; p = 0.01), opioid (OR 0.41, 95% CI 0.26-0.63; p < 0.001), and beta-blocker (OR 0.26, 95% CI 0.12-0.61; p = 0.002) use, and co-existing psychopathology (p < 0.001 in univariable analysis). CONCLUSION: Headaches represent a significant cause of unit attrition in personnel deployed in military operations, with physical trauma and co-existing psychopathology associated with poorer outcomes.

Does sensory stimulation threshold affect lumbar facet radiofrequency denervation outcomes? A prospective clinical correlational study.

BACKGROUND: Radiofrequency facet denervation is one of the most frequently performed procedures for chronic low back pain. Although sensory stimulation is generally used as a surrogate measure to denote sufficient proximity of the electrode to the nerve, no study has examined whether stimulation threshold influences outcome. METHODS: We prospectively recorded data in 61 consecutive patients undergoing lumbar facet radiofrequency denervation who experienced significant pain relief after medial branch blocks. For each nerve lesioned, multiple attempts were made to maximize sensory stimulation threshold (SST). Mean SST was calculated on the basis of the lowest stimulation perceived at 0.1-V increments for each medial branch. A positive outcome was defined as a ≥50% reduction in back pain coupled with a positive satisfaction score lasting ≥3 months. The relationship between mean SST and denervation outcomes was evaluated via a receiver's operating characteristic (ROC) curve, and stratifying outcomes on the basis of various cutoff values. RESULTS: No correlation was noted between mean SST and pain relief at rest (Pearson's r=-0.01, 95% confidence interval [CI]: -0.24 to 0.23, P=0.97), with activity (r=-0.17, 95% CI: -0.40 to 0.07, P=0.20), or a successful outcome. No optimal SST could be identified. CONCLUSIONS: There is no significant relationship between mean SST during lumbar facet radiofrequency denervation and treatment outcome, which may be due to differences in general sensory perception. Because stimulation threshold was optimized for each patient, these data cannot be interpreted to suggest that sensory testing should not be performed, or that high sensory stimulation thresholds obtained on the first attempt should be deemed acceptable.

Diagnoses and factors associated with medical evacuation and return to duty among nonmilitary personnel participating in military operations in Iraq and Afghanistan.

BACKGROUND: Nonmilitary personnel play an increasingly critical role in modern wars. Stark differences exist between the demographic characteristics, training and missions of military and nonmilitary members. We examined the differences in types of injury and rates of returning to duty among nonmilitary and military personnel participating in military operations in Iraq and Afghanistan. METHODS: We collected data for nonmilitary personnel medically evacuated from military operations in Iraq and Afghanistan between 2004 and 2007. We compared injury categories and return-to-duty rates in this group with previously published data for military personnel and identified factors associated with return to duty. RESULTS: Of the 2155 medically evacuated nonmilitary personnel, 74.7% did not return to duty. War-related injuries in this group accounted for 25.6% of the evacuations, the most common causes being combat-related injuries (55.4%) and musculoskeletal/spinal injuries (22.9%). Among individuals with non-war-related injuries, musculoskeletal injuries accounted for 17.8% of evacuations. Diagnoses associated with the highest return-to-duty rates in the group of nonmilitary personnel were psychiatric diagnoses (15.6%) among those with war-related injuries and noncardiac chest or abdominal pain (44.0%) among those with non-war-related injuries. Compared with military personnel, nonmilitary personnel with war-related injuries were less likely to return to duty (4.4% v. 5.9%, p = 0.001) but more likely to return to duty after non-war-related injuries (32.5% v. 30.7%, p = 0.001). INTERPRETATION: Compared with military personnel, nonmilitary personnel were more likely to be evacuated with non-war-related injuries but more likely to return to duty after such injuries. For evacuations because of war-related injuries, this trend was reversed.

Noncardiac chest pain during war.

OBJECTIVES: Noncardiac chest pain (NCCP) has emerged as one of the biggest challenges facing military healthcare providers. The objectives of this study are to determine disease burden and diagnostic breakdown of NCCP, and to identify factors associated with return-to-duty (RTD). METHODS: Data were prospectively collected from the Deployed Warrior Medical Management Center in Germany on 1935 service and nonservice members medically evacuated out of Operations Iraqi and Enduring Freedom for a primary diagnosis of NCCP between 2004 and 2007. Electronic medical records were reviewed to examine the effect myriad factors had on RTD. RESULTS: One thousand nine hundred thirty-five personnel were medically evacuated with a diagnosis of NCCP, of whom 92% were men, 70% were in the Army, and 79% sustained their injury in Iraq. Fifty-eight percent returned to duty. The most common causes were musculoskeletal (23.4%), unknown (23%), cardiac (21%), pulmonary (13.9%), and gastrointestinal (11.9%). Factors associated with a positive outcome were being a commissioned officer [adjusted odds ratio (OR) 1.87, P=0.009]; serving in the navy (OR 2.25, P=0.051); having a noncardiac etiology, including gastrointestinal (adjusted OR 5.65, P<0.001), musculoskeletal (OR 4.19, P<0.001), pulmonary (OR 1.80, P=0.018), psychiatric (OR 2.11, P=0.040), or neuropathic (OR 5.05, P=0.040) causes; smoking history (OR 1.54, P=0.005); and receiving no treatment for chest pain (OR 2.17, P=0.006). Covariates associated with a decreased likelihood of RTD were service in Iraq (OR 0.68, P=0.029) and treatment with opioids (OR 0.59, P=0.006) or adjuvants (OR 0.61, P=0.026). CONCLUSIONS: NCCP represents a significant cause of soldier attrition during combat operations, but is associated with the highest RTD rate among any diagnostic category. Among various causes, gastrointestinal is associated with the highest RTD rate.

Multicenter, randomized, comparative cost-effectiveness study comparing 0, 1, and 2 diagnostic medial branch (facet joint nerve) block treatment paradigms before lumbar facet radiofrequency denervation.

BACKGROUND: Among patients presenting with axial low back pain, facet arthropathy accounts for approximately 10-15% of cases. Facet interventions are the second most frequently performed procedures in pain clinics across the United States. Currently, there are no uniformly accepted criteria regarding how best to select patients for radiofrequency denervation. METHODS: A randomized, multicenter study was performed in 151 subjects with suspected lumbar facetogenic pain comparing three treatment paradigms. Group 0 received radiofrequency denervation based solely on clinical findings; group 1 underwent denervation contingent on a positive response to a single diagnostic block; and group 2 proceeded to denervation only if they obtained a positive response to comparative blocks done with lidocaine and bupivacaine. A positive outcome was predesignated as > or =50% pain relief coupled with a positive global perceived effect persisting for 3 months. RESULTS: In group 0, 17 patients (33%) obtained a successful outcome at 3 months versus eight patients (16%) in group 1 and 11 (22%) patients in group 2. Denervation success rates in groups 0, 1, and 2 were 33, 39, and 64%, respectively. Pain scores and functional capacity were significantly lower at 3 months but not at 1 month in group 2 subjects who proceeded to denervation compared with patients in groups 0 and 1. The costs per successful treatment in groups 0, 1, and 2 were $6,286, $17,142, and $15,241, respectively. CONCLUSIONS: Using current reimbursement scales, these findings suggest that proceeding to radiofrequency denervation without a diagnostic block is the most cost-effective treatment paradigm.

Diagnoses and factors associated with medical evacuation and return to duty for service members participating in Operation Iraqi Freedom or Operation Enduring Freedom: a prospective cohort study.

BACKGROUND: Anticipation of the types of injuries that occur in modern warfare is essential to plan operations and maintain a healthy military. We aimed to identify the diagnoses that result in most medical evacuations, and ascertain which demographic and clinical variables were associated with return to duty. METHODS: Demographic and clinical data were prospectively obtained for US military personnel who had been medically evacuated from Operation Iraqi Freedom or Operation Enduring Freedom (January, 2004-December, 2007). Diagnoses were categorised post hoc according to the International Classification of Diseases codes that were recorded at the time of transfer. The primary outcome measure was return to duty within 2 weeks. FINDINGS: 34 006 personnel were medically evacuated, of whom 89% were men, 91% were enlisted, 82% were in the army, and 86% sustained an injury in Iraq. The most common reasons for medical evacuation were: musculoskeletal and connective tissue disorders (n=8104 service members, 24%), combat injuries (n=4713, 14%), neurological disorders (n=3502, 10%), psychiatric diagnoses (n=3108, 9%), and spinal pain (n=2445, 7%). The factors most strongly associated with return to duty were being a senior officer (adjusted OR 2.01, 95% CI 1.71-2.35, p<0.0001), having a non-battle-related injury or disease (3.18, 2.77-3.67, p<0.0001), and presenting with chest or abdominal pain (2.48, 1.61-3.81, p<0.0001), a gastrointestinal disorder (non-surgical 2.32, 1.51-3.56, p=0.0001; surgical 2.62, 1.69-4.06, p<0.0001), or a genitourinary disorder (2.19, 1.43-3.36, p=0.0003). Covariates associated with a decreased probability of return to duty were serving in the navy or coast guard (0.59, 0.45-0.78, p=0.0002), or marines (0.86, 0.77-0.96, p=0.0083); and presenting with a combat injury (0.27, 0.17-0.44, p<0.0001), a psychiatric disorder (0.28, 0.18-0.43, p<0.0001), musculoskeletal or connective tissue disorder (0.46, 0.30-0.71, p=0.0004), spinal pain (0.41, 0.26-0.63, p=0.0001), or other wound (0.54, 0.34-0.84, p=0.0069). INTERPRETATION: Implementation of preventive measures for service members who are at highest risk of evacuation, forward-deployed treatment, and therapeutic interventions could reduce the effect of non-battle-related injuries and disease on military readiness. FUNDING: John P Murtha Neuroscience and Pain Institute, and US Army Regional Anesthesia and Pain Management Initiative.

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.

Vena cava filters in spinal cord injuries: evolving technology.

BACKGROUND: Asymptomatic deep venous thrombosis (DVT) has been reported in 60% to 100% of persons with spinal cord injury (SCI). Several guidelines have been published detailing recommended venous thromboembolism (VTE) prophylaxis after acute SCI. Low-molecular-weight heparin, intermittent pneumatic compression (IPC) devices, and/or graduated compression stockings are recommended. Vena cava filters (VCFs) are recommended for secondary prophylaxis in certain situations. OBJECTIVE: To clarify the use of vena cava filters in patients with SCI. METHODS: Literature review. RESULTS: Prophylactic use of vena cava filters has expanded in trauma patients, including individuals with SCI. Filter placement effectively prevents pulmonary emboli and has a low complication rate. Indications include pulmonary embolus while on anticoagulant therapy, presence of pulmonary embolus and contraindication for anticoagulation, and documented free-floating ileofemoral thrombus. VCFs should be considered in patients with complete motor paralysis caused by lesions in the high cervical cord (C2 and C3), with poor cardiopulmonary reserve, or with thrombus in the inferior vena cava despite anticoagulant prophylaxis. Three optional retrievable filters that are approved for use are discussed. CONCLUSION: Retrievable VCFs are a safe, feasible option for secondary prophylaxis of VTE in patients with SCI. Objective criteria for temporary and permanent placement need to be defined.

Clinical use of cholinomimetic agents: a review.

BACKGROUND: There are many agents in clinical use that manipulate central nervous system levels of epinephrine, dopamine, and serotonin. However, development of pharmacological options to manipulate central acetylcholine systems has lagged behind because of poor penetration of the blood-brain barrier and significant peripheral nervous system side effects. Newer agents have demonstrated some efficacy in the management of behavioral and cognitive side effects in Alzheimer's disease, and preliminary data in traumatic brain injury suggest acetylcholine esterase inhibitors may play a significant role in the treatment of this patient population as well. CONCLUSIONS: In this article, the basic neuroanatomy and pharmacology of the central acetylcholine system are reviewed, along with agents currently available for clinical use.