Permanent Peripheral Nerve Stimulator for Complex Regional Pain Syndrome of the Forearm and Hand.

A 51-year-old woman with diabetes and depression was referred to the anesthesia pain clinic with a 15-year history of complex regional pain syndrome type I of the right forearm and hand in the radial sensory nerve distribution. There was no recognized antecedent trauma and she had failed both medical treatment and radial sensory nerve decompression surgery. An ultrasound-guided local anesthetic block of the radial nerve in the upper arm resulted in partial and temporary improvement in pain. She subsequently underwent trial of a peripheral nerve stimulator (PNS) followed by permanent PNS implant placement over the radial nerve proper proximal to the elbow. Within the first month of use, she endorsed substantially improved pain and strength in her right hand. These improvements were sustained for more than 1 year. Applications of PNS technology for treatment of extremity complex regional pain syndrome and neuropathic extremity pain in general are reviewed.

Peripheral nerve blocks of wrist and finger flexors can increase hand opening in chronic hemiparetic stroke.

Introduction: Hand opening is reduced by abnormal wrist and finger flexor activity in many individuals with stroke. This flexor activity also limits hand opening produced by functional electrical stimulation (FES) of finger and wrist extensor muscles. Recent advances in electrical nerve block technologies have the potential to mitigate this abnormal flexor behavior, but the actual impact of nerve block on hand opening in stroke has not yet been investigated. Methods: In this study, we applied the local anesthetic ropivacaine to the median and ulnar nerve to induce a complete motor block in 9 individuals with stroke and observed the impact of this block on hand opening as measured by hand pentagonal area. Volitional hand opening and FES-driven hand opening were measured, both while the arm was fully supported on a haptic table (Unloaded) and while lifting against gravity (Loaded). Linear mixed effect regression (LMER) modeling was used to determine the effect of Block. Results: The ropivacaine block allowed increased hand opening, both volitional and FES-driven, and for both unloaded and loaded conditions. Notably, only the FES-driven and Loaded condition's improvement in hand opening with the block was statistically significant. Hand opening in the FES and Loaded condition improved following nerve block by nearly 20%. Conclusion: Our results suggest that many individuals with stroke would see improved hand-opening with wrist and finger flexor activity curtailed by nerve block, especially when FES is used to drive the typically paretic finger and wrist extensor muscles. Such a nerve block (potentially produced by aforementioned emerging electrical nerve block technologies) could thus significantly address prior observed shortcomings of FES interventions for individuals with stroke.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation of C2 Dorsal Root Ganglion for the Treatment of Refractory Atypical Facial Pain: A Technical Report and Case Series.

BACKGROUND: Chronic craniofacial pain can be difficult to manage clinically. This technical report documents the peripheral nerve stimulation of the C2 dorsal root ganglion as an effective modality to treat refractory atypical facial pain. MATERIALS AND METHODS: In this case series, three patients with chronic refractory atypical facial pain and p >50% pain relief following diagnostic C2 dorsal root ganglion blockade underwent ultrasound-guided percutaneous placement of a peripheral nerve stimulator adjacent to the C2 dorsal root ganglion. Patients were then observed clinically and monitored for improvement in symptoms and adverse events. RESULTS: Three patients underwent peripheral nerve stimulator placement. At follow-up, there were no reported adverse events, and all patients reported satisfactory improvement in pain. CONCLUSION: The neuromodulation of C2 dorsal root ganglion via ultrasound-guided percutaneously implanted peripheral nerve stimulator is a novel and potentially effective approach for the management of chronic refractory craniofacial pain.

Spinal Anesthesia or General Anesthesia for Hip Surgery in Older Adults.

BACKGROUND: The effects of spinal anesthesia as compared with general anesthesia on the ability to walk in older adults undergoing surgery for hip fracture have not been well studied. METHODS: We conducted a pragmatic, randomized superiority trial to evaluate spinal anesthesia as compared with general anesthesia in previously ambulatory patients 50 years of age or older who were undergoing surgery for hip fracture at 46 U.S. and Canadian hospitals. Patients were randomly assigned in a 1:1 ratio to receive spinal or general anesthesia. The primary outcome was a composite of death or an inability to walk approximately 10 ft (3 m) independently or with a walker or cane at 60 days after randomization. Secondary outcomes included death within 60 days, delirium, time to discharge, and ambulation at 60 days. RESULTS: A total of 1600 patients were enrolled; 795 were assigned to receive spinal anesthesia and 805 to receive general anesthesia. The mean age was 78 years, and 67.0% of the patients were women. A total of 666 patients (83.8%) assigned to spinal anesthesia and 769 patients (95.5%) assigned to general anesthesia received their assigned anesthesia. Among patients in the modified intention-to-treat population for whom data were available, the composite primary outcome occurred in 132 of 712 patients (18.5%) in the spinal anesthesia group and 132 of 733 (18.0%) in the general anesthesia group (relative risk, 1.03; 95% confidence interval [CI], 0.84 to 1.27; P = 0.83). An inability to walk independently at 60 days was reported in 104 of 684 patients (15.2%) and 101 of 702 patients (14.4%), respectively (relative risk, 1.06; 95% CI, 0.82 to 1.36), and death within 60 days occurred in 30 of 768 (3.9%) and 32 of 784 (4.1%), respectively (relative risk, 0.97; 95% CI, 0.59 to 1.57). Delirium occurred in 130 of 633 patients (20.5%) in the spinal anesthesia group and in 124 of 629 (19.7%) in the general anesthesia group (relative risk, 1.04; 95% CI, 0.84 to 1.30). CONCLUSIONS: Spinal anesthesia for hip-fracture surgery in older adults was not superior to general anesthesia with respect to survival and recovery of ambulation at 60 days. The incidence of postoperative delirium was similar with the two types of anesthesia. (Funded by the Patient-Centered Outcomes Research Institute; REGAIN ClinicalTrials.gov number, NCT02507505.).

American Society of Regional Anesthesia and Pain Medicine expert panel recommendations on point-of-care ultrasound education and training for regional anesthesiologists and pain physicians-part II: recommendations.

Point-of-care ultrasound (POCUS) is a critical skill for all regional anesthesiologists and pain physicians to help diagnose relevant complications related to routine practice and guide perioperative management. In an effort to inform the regional anesthesia and pain community as well as address a need for structured education and training, the American Society of Regional Anesthesia and Pain Medicine Society (ASRA) commissioned this narrative review to provide recommendations for POCUS. The recommendations were written by content and educational experts and were approved by the guidelines committee and the Board of Directors of the ASRA. In part II of this two-part series, learning goals and objectives were identified and outlined for achieving competency in the use of POCUS, specifically, airway ultrasound, lung ultrasound, gastric ultrasound, the focus assessment with sonography for trauma exam, and focused cardiac ultrasound, in the perioperative and chronic pain setting. It also discusses barriers to POCUS education and training and proposes a list of educational resources. For each POCUS section, learning goals and specific skills were presented in the Indication, Acquisition, Interpretation, and Medical decision-making framework.

American Society of Regional Anesthesia and Pain Medicine expert panel recommendations on point-of-care ultrasound education and training for regional anesthesiologists and pain physicians-part I: clinical indications.

Point-of-care ultrasound (POCUS) is a critical skill for all regional anesthesiologists and pain physicians to help diagnose relevant complications related to routine practice and guide perioperative management. In an effort to inform the regional anesthesia and pain community as well as address a need for structured education and training, the American Society of Regional Anesthesia and Pain Medicine (ASRA) commissioned this narrative review to provide recommendations for POCUS. The guidelines were written by content and educational experts and approved by the Guidelines Committee and the Board of Directors of the ASRA. In part I of this two-part series, clinical indications for POCUS in the perioperative and chronic pain setting are described. The clinical review addresses airway ultrasound, lung ultrasound, gastric ultrasound, the focus assessment with sonography for trauma examination and focused cardiac ultrasound for the regional anesthesiologist and pain physician. It also provides foundational knowledge regarding ultrasound physics, discusses the impact of handheld devices and finally, offers insight into the role of POCUS in the pediatric population.

Thoracoscopic lung biopsy under regional anesthesia for interstitial lung disease.

BACKGROUND: Interstitial lung disease (ILD) management guidelines support lung biopsy-guided therapy. However, the high mortality associated with thoracoscopic lung biopsy using general anesthesia (GA) in patients with ILD has deterred physicians from offering this procedure and adopt a diagnostic approach based on high-resolution CT. Here we report that thoracoscopy under regional anesthesia could be a safer alternative for lung biopsy and effectively guide ILD treatment. METHODS: This was a single-center retrospective review of prospectively maintained database and consisted of patients who underwent thoracoscopic lung biopsy between March 2016 and March 2018. Patients were divided into two groups: (A) GA, and (B) regional anesthesia using monitored anesthesia care (MAC) and thoracic epidural anesthesia (TEA). RESULTS: During the study period, 44 patients underwent thoracoscopic lung biopsy. Of these, 15 underwent MAC/TEA. There were no significant differences between the two groups with regard to pulmonary function test and clinicodemographic profile. However, operative time and hospital stay were shorter in MAC/TEA group (32.5±18.5 min vs 50.8±18.4; p=0.004, 1.0±1.3 days vs 10.0±34.7 days; p<0.001, respectively). Eight patients in the GA group, but none in the MAC/TEA group, experienced worsening of ILD after lung biopsy (p=0.03). Additionally, one patient in the GA group died due to acute ILD worsening. No cases of MAC/TEA group had to be converted to GA. In all cases a pathological diagnosis could be made. CONCLUSIONS: Thoracoscopy using regional anesthesia might be a safer alternative to lung biopsy in patients with ILD.

Technical considerations for approaches to the ultrasound-guided maxillary nerve block via the pterygopalatine fossa: a literature review.

BACKGROUND AND OBJECTIVES: Blockade of the trigeminal nerve and its branches is an effective diagnostic tool and potential treatment of facial pain. Ultrasound-guided injections in the pterygopalatine fossa (PPF) to block the trigeminal nerve divisions and sphenopalatine ganglion have been described but a consensus has yet to be reached over the ideal approach. We sought to delineate and compare the various approaches to the ultrasound-guided trigeminal divisions blockade via the PPF. METHODS: The literature search was performed by searching the National Library of Medicine's PubMed database, the Cochrane Database of Systematic Reviews and Google Scholar within the date range of January 2009-March 2019 for keywords targeted toward "trigeminal nerve," "maxillary nerve," or "pterygopalatine fossa," "ultrasound," and "nerve block," using an English language restriction. Six papers were included in the final review: one prospective double-blinded randomized controlled trial, one prospective descriptive study, one case series, two case reports, and one cadaveric study. RESULTS: There are three main approaches to the ultrasound-guided trigeminal nerve branches blockade via the PPF: anterior infrazygomatic in-plane, posterior infrazygomatic in-plane, and suprazygomatic out-of-plane approaches. Each showed injectate spread to the PPF in cadaver, adult and pediatric patients, respectively.1-5 Injectate used varied from 3 to 5 mL to 0.15 mL/kg. CONCLUSIONS: These studies demonstrated that the PPF is a readily accessible target for the ultrasound-guided maxillary nerve block via three main approaches.2 The ideal approach is yet to be determined and must be further explored.

Percutaneous 60-day peripheral nerve stimulation implant provides sustained relief of chronic pain following amputation: 12-month follow-up of a randomized, double-blind, placebo-controlled trial.

INTRODUCTION: Peripheral nerve stimulation (PNS) has historically been used to treat chronic pain, but generally requires implantation of a permanent system for sustained relief. A recent study found that a 60-day PNS treatment decreases post-amputation pain, and the current work investigates longer-term outcomes out to 12 months in the same cohort. METHODS: As previously reported, 28 traumatic lower extremity amputees with residual and/or phantom limb pain were randomized to receive 8 weeks of PNS (group 1) or 4 weeks of placebo followed by a crossover 4 weeks of PNS (group 2). Percutaneous leads were implanted under ultrasound guidance targeting the femoral and sciatic nerves. During follow-up, changes in average pain and pain interference were assessed using the Brief Pain Inventory-Short Form and comparing with baseline. RESULTS: Significantly more participants in group 1 reported ≥50% reductions in average weekly pain at 12 months (67%, 6/9) compared with group 2 at the end of the placebo period (0%, 0/14, p=0.001). Similarly, 56% (5/9) of participants in group 1 reported ≥50% reductions in pain interference at 12 months, compared with 2/13 (15%, p=0.074) in group 2 at crossover. Reductions in depression were also statistically significantly greater at 12 months in group 1 compared with group 2 at crossover. CONCLUSIONS: This work suggests that percutaneous PNS delivered over a 60-day period may provide significant carry-over effects including pain relief, potentially avoiding the need for a permanently implanted system while enabling improved function in patients with chronic pain. TRIAL REGISTRATION NUMBER: NCT01996254.

Ultrasound-Guided Pulsed Radiofrequency of C2 Dorsal Root Ganglion as Adjuvant Treatment for Chronic Headache Disorders: A Case Report.

Cluster headaches are characterized by unilateral sudden onset of intense, brief, sharp pain along the side of the face around the eye. Patients often can have symptoms that are resistant to medications, nerve blocks, and surgical treatments. There is increasing evidence of anatomical and functional connections between the trigeminal and occipital nerves. We present a patient with cluster headache presenting with chronic ipsilateral facial pain with nasal congestion and left eye pain who achieved sustained pain relief with an ultrasound-guided injection into the pterygopalatine fossa in conjunction with an ultrasound-guided pulsed radiofrequency ablation procedure involving the C2 dorsal root ganglion.

Percutaneous peripheral nerve stimulation for the treatment of chronic neuropathic postamputation pain: a multicenter, randomized, placebo-controlled trial.

BACKGROUND AND OBJECTIVES: Chronic neuropathic pain is a common challenging condition following amputation. Recent research demonstrated the feasibility of percutaneously implanting fine-wire coiled peripheral nerve stimulation (PNS) leads in proximity to the sciatic and femoral nerves for postamputation pain. A multicenter, double-blinded, randomized, placebo-controlled study collected data on the safety and effectiveness of percutaneous PNS for chronic neuropathic pain following amputation. METHODS: Twenty-eight lower extremity amputees with postamputation pain were enrolled. Subjects underwent ultrasound-guided implantation of percutaneous PNS leads and were randomized to receive PNS or placebo for 4 weeks. The placebo group then crossed over and all subjects received PNS for four additional weeks. The primary efficacy endpoint evaluated the proportion of subjects reporting ≥50% pain reduction during weeks 1-4. RESULTS: A significantly greater proportion of subjects receiving PNS (n=7/12, 58%, p=0.037) demonstrated ≥50% reductions in average postamputation pain during weeks 1-4 compared with subjects receiving placebo (n=2/14, 14%). Two subjects were excluded from efficacy analysis due to eligibility changes. Significantly greater proportions of PNS subjects also reported ≥50% reductions in pain (n=8/12, 67%, p=0.014) and pain interference (n=8/10, 80%, p=0.003) after 8 weeks of therapy compared with subjects receiving placebo (pain: n=2/14, 14%; pain interference: n=2/13, 15%). Prospective follow-up is ongoing; four of five PNS subjects who have completed 12-month follow-up to date reported ≥50% pain relief. CONCLUSIONS: This work demonstrates that percutaneous PNS therapy may provide enduring clinically significant pain relief and improve disability in patients with chronic neuropathic postamputation pain. TRIAL REGISTRATION NUMBER: NCT01996254.

The Effects of Selective Muscle Weakness on Muscle Coordination in the Human Arm.

Despite the fundamental importance of muscle coordination in daily life, it is currently unclear how muscle coordination adapts when the musculoskeletal system is perturbed. In this study, we quantified the impact of selective muscle weakness on several metrics of muscle coordination. Seven healthy subjects performed 2D and 3D isometric force target matches, while electromyographic (EMG) signals were recorded from 13 elbow and shoulder muscles. Subsequently, muscle weakness was induced by a motor point block of brachialis muscle. Postblock subjects repeated the force generation tasks. We quantified muscle coordination pre- and postblock using three metrics: tuning curve preferred direction, tuning curve area, and motor modules analysis via nonnegative matrix factorization. For most muscles, the tuning direction for the 2D protocol was not substantially altered postblock, while tuning areas changed more drastically. Typically, five motor modules were identified from the 3D task, and four motor modules were identified in the 2D task; this result held across both pre- and postblock conditions. The composition of one or two motor modules, ones that involved mainly the activation of shoulder muscles, was altered postblock. Our results demonstrate that selective muscle weakness can induce nonintuitive alternations in muscle coordination in the mechanically redundant human arm.

Transversus Abdominis Plane Blockade as Part of a Multimodal Postoperative Analgesia Plan in Patients Undergoing Radical Cystectomy.

BACKGROUND: Radical cystectomy (RC) is a morbid procedure with frequent complications that may benefit from implementation of an enhanced recovery after surgery (ERAS) protocol. OBJECTIVE: To examine the benefits of a multimodal analgesic plan that uses continuous transversus abdominis plane (TAP) blockade as part of an ERAS protocol after RC. METHODS: A retrospective comparison of consecutive patients undergoing RC over a 4-year period was conducted. Patients were designated as having surgery either before or after implementation of an ERAS protocol. A major component of the ERAS protocol was a multi-modal analgesia plan with TAP blockade. Patient demographics, comorbidities, operative details, and outcomes, including days to flatus, bowel movement (BM), narcotic usage, and length of stay (LOS) were compared. RESULTS: In total, 171 patients were included: 100 pre-ERAS and 71 ERAS. There were no differences in age, smoking status, operative approach, or diversion type. The patients in the ERAS cohort were less likely to be male, had a higher median BMI, and more likely to have received neoadjuvant chemotherapy. Total and early postoperative narcotic use were lower in the ERAS cohort: 89 vs. 336 mg (p < 0.001) and 62 vs 203 mg (p = 0.001), respectively. The ERAS cohort had fewer days to flatus (3 vs. 4, p < 0.001) and fewer days to bowel movement (4 vs. 5, p < 0.001). Median LOS was shorter in the ERAS cohort (7 vs. 8.5d, p = 0.001). There were no differences in complications or readmission rates between the two cohorts. CONCLUSIONS: TAP blockade as part of an ERAS multi-modal pain plan is associated with low narcotic usage, and significant improvement in time to flatus, BM, and LOS compared to traditional post-RC pain management.

The Effect of Intraoperative Systemic Lidocaine on Postoperative Persistent Pain Using Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials Criteria Assessment Following Breast Cancer Surgery: A Randomized, Double-Blind, Placebo-Controlled Trial.

OBJECTIVE: To compare the incidence in postsurgical persistent pain following breast cancer surgery in women receiving intravenous lidocaine compared to saline using validated pain instruments in accordance with the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) recommendations. METHODS: The study was a randomized, double-blinded, placebo-controlled, clinical trial. Subjects were randomized into Group 1 (1.5 mg/kg bolus of intravenous lidocaine followed by a 2 mg/kg/hour infusion) or Group 2 (normal saline at the same bolus and infusion rate). Patients were evaluated at 3 and 6 months for the presence of chronic persistent postsurgical pain. RESULTS: One hundred forty-eight patients were included in the study analysis. There were no differences in quality of recovery, pain burden, or opioid consumption between groups at 24 hours. Pain (yes/no) at 6 months attributed to surgery was reported in 29% of Group 2 vs. 13% of Group 1 patients (P = 0.04); however, only 3 subjects (5%) in Group 1 and 2 subjects (3%) in Group 2 met IMMPACT criteria for persistent postoperative pain (P = 0.99). DISCUSSION: Perioperative infusion of lidocaine has been reported to decrease the incidence of postsurgical pain at 3 and 6 months following mastectomy using dichotomous (yes/no) scoring. Although intravenous lidocaine reduced the reported incidence of pain at rest at 6 months, pain with activity, pain qualities, and the physical or emotional impact of the pain were unaffected. Future studies evaluating postsurgical persistent pain should adhere to the IMMPACT recommendations in order to more accurately describe the effect of an intervention on persistent pain.

Effect of Arm Positioning on Entrapment of Infraclavicular Nerve Block Catheter.

Continuous brachial plexus nerve block catheters are commonly inserted for postoperative analgesia after upper extremity surgery. Modifications of the insertion technique have been described to improve the safety of placing an infraclavicular brachial plexus catheter. Rarely, these catheters may become damaged or entrapped, complicating their removal. We describe a case of infraclavicular brachial plexus catheter entrapment related to differences in arm positioning during catheter placement and removal. Written authorization to obtain, use, and disclose information and images was obtained from the patient.

Single-Dose Adductor Canal Block With Local Infiltrative Analgesia Compared With Local Infiltrate Analgesia After Total Knee Arthroplasty: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND AND OBJECTIVES: A single-dose adductor canal block can provide postoperative analgesia for patients undergoing total knee arthroplasty (TKA). The purpose of this study was to assess postoperative opioid consumption after ultrasound-guided single-injection bupivacaine compared with saline adductor canal block for patients undergoing TKA. METHODS: After institutional review board approval, written informed consent was obtained from patients (>18 years old) undergoing elective TKA. Subjects were randomized into 2 groups as follows: adductor canal blockade with 10 mL of bupivacaine 0.25% with epinephrine 1:300,000 or 10 mL of normal saline. All patients received a periarticular infiltration mixture intraoperatively with scheduled and patient requested oral and IV analgesics postoperatively for breakthrough pain. Personnel blinded to group allocation recorded pain scores and opioid consumption every 6 hours. Pain burden, area under the numeric rating score for pain, was calculated for 36 hours. The primary outcome was postoperative IV/IM morphine (mg morEq) consumption at 36 hours after surgery. RESULTS: Forty (28 women/12 men) subjects were studied. Postoperative opioid consumption was reduced in the bupivacaine 48 (39 to 61) mg morEq compared with saline 60 (49 to 85) mg morEq, difference -12 (-33 to -2) mg morEq (P = 0.03). Pain burden at rest was decreased in the bupivacaine 71 (37 to 120) score · hours compared with saline 131 (92 to 161) score · hours, difference -60 (-93 to -14) score · hours (P = 0.009). CONCLUSIONS: Adductor canal blockade with bupivacaine 0.25% with epinephrine 1:300,000 effectively reduces pain and opioid requirement in the postoperative period after TKA. Adductor canal blockade is an effective pain management adjunct for patients undergoing TKA.

Greater Cephalad Extent of Thoracic Epidural Sensory Anesthesia After Lidocaine and Epinephrine Test Dose Correlates With Analgesic Consumption and Pain Burden After Uterine Fibroid Artery Embolization.

BACKGROUND AND OBJECTIVES: Ischemic pain after uterine fibroid artery embolization (UFAE) is often severe. We evaluated the sensory anesthesia extent from thoracic epidural catheter test injection of lidocaine 75 mg with epinephrine 25 µg as a predictor of analgesia effectiveness after UFAE. METHODS: One hundred patients were studied. Pinprick and cold insensitivity were assessed from L3 to T4 at 5-minute intervals for 30 minutes after the test dose. Thoracic epidural management was standardized. Total epidural infusate and numeric rating of pain (0-10) scores were recorded. RESULTS: Pinprick or cold insensitivity at T9 to T10 dermatome was present in 94% of patients. Forty-six subjects (45%) achieved a sensory level at or above the T6 dermatome at 30 minutes. Median analgesic consumption in the first hour and at catheter discontinuation was greater in subjects with a sensory level above T6 compared with those below T6: first hour difference, 7 mL (95% confidence interval [95% CI], 0-12 mL; P = 0.02); difference at discontinuation, 21 mL (95% CI, 4-35 mL; P = 0.02). The area under the pain score by time curve for the first 24 hours was greater in patients with sensory levels above T6: difference 32 score · hour (95% CI, 12 score · h - 60 score · h; P = 0.001). CONCLUSIONS: Sensory anesthesia spread above the T6 dermatome 30 minutes after a test dose of 1.5% lidocaine was an independent predictor of the analgesic consumption after UFAE. Pain burden and oral opioid consumption were also increased in subjects who demonstrated a high sensory spread after the test dose.

Use of Peripheral Nerve Blocks with Sedation for Total Knee Arthroplasty in a Patient with Contraindication for General Anesthesia.

Although peripheral nerve blocks are commonly used to provide postoperative analgesia after total knee arthroplasty (TKA) and other lower extremity procedures, these blocks are rarely used for intraoperative anesthesia. Most TKAs are performed under general anesthesia (GA) or neuraxial anesthesia (NA). The knee has a complex sensory innervation that makes surgical anesthesia difficult with peripheral nerve blocks alone. Rarely are both GA and NA relatively contraindicated and alternatives are considered. We present a patient who underwent TKA performed under peripheral nerve block and sedation alone.