A comparison of the continuous supraclavicular brachial plexus block using the proximal longitudinal oblique approach and the interscalene brachial plexus block for arthroscopic shoulder surgery: A randomised, controlled, double-blind trial

BACKGROUND

Continuous interscalene brachial plexus block (ISB) is widely used for arthroscopic shoulder surgery, but the incidence of hemidiaphragmatic paresis (HDP) has been reported to reach 100%. Several methods, including injections distal to the C5-C6 nerve roots, have been attempted to reduce the HDP incidence. However, catheter placement distal to the C5-C6 nerve roots interferes with the surgical site.

OBJECTIVE

Our primary objective was to describe a new technique, the supraclavicular brachial plexus block (SCB), using the proximal longitudinal oblique approach (PLO-SCB), which can facilitate catheter placement and, when compared with ISB, to test whether this would provide noninferior analgesia and spare the phrenic nerve.

DESIGN

Prospective, randomised, double-blind study.

SETTING

Operating rooms, postanaesthesia care unit, and wards.

PATIENTS

Seventy-six patients aged 20 to 80 years scheduled for arthroscopic shoulder surgery.

INTERVENTIONS

Patients were randomly assigned to the continuous PLO-SCB ( n  = 40) or the continuous ISB ( n  = 40) groups. All patients received an initial low-volume single-injection (5 ml 0.75% ropivacaine) followed by a patient-controlled infusion of 0.15% ropivacaine.

MAIN OUTCOME MEASURES

The primary outcomes were the incidence of HDP and pain scores. Secondary outcomes were respiratory function, postoperative analgesic consumption, sensory and motor function, and complications.

RESULTS

The HDP incidence was significantly lower in the PLO-SCB group than in the ISB group at 30 min after block injection: 0% (0 of 38 patients) and 73.7% (28 of 38 patients), respectively ( P  < 0.001). Similarly, at 24 h after surgery, the incidences were 23.7% (9 of 38 patients) and 47.4% (18 of 38 patients) in the PLO-SCB and ISB groups, respectively ( P  = 0.002). Median [IQR] NRS pain scores at rest measured after surgery in the ISB and PLO-SCB groups were similar: immediately after surgery, 1 [0 to 2] vs. 1 [0 to 1], P  = 0.06); at 30 min, 2 [0.25 to 2] vs. 1 [0 to 2], P  = 0.065); and at 24 h 2 [0.25 to 3] vs. 1 [0 to 3], P  = 0.47, respectively.

CONCLUSION

For major shoulder surgery, compared with continuous ISB, continuous PLO-SCB was more sparing of diaphragmatic and respiratory function while providing noninferior analgesia. Catheter placement via the PLO approach is feasible without interfering with the surgical field.

TRIAL REGISTRATION

Registered by the Clinical Trial Registry of Korea (Seoul, Korea; KCT0004759, http: cris.nih.go.kr, principal investigator: Hyungtae Kim).

Reconsidering injection volume for caudal epidural block in young pediatric patients: a dynamic flow tracking experimental study

INTRODUCTION

Caudal epidural block is a commonly used analgesic technique in pediatric patients. Ultrasound could be used to increase the accuracy of the block by visual confirmation of the drug-spreading. Therefore, we aimed to estimate the cephalad spread of injection volume by caudal route using dynamic ultrasound imaging in young pediatric patients.

METHODS

Forty patients, aged 6-24 months, undergoing foot surgery were included. After inducing general anesthesia, an angiocatheter was inserted into the sacral canal under ultrasound guidance. Thereafter, the probe was placed in the paramedian sagittal oblique position, and prepared 0.15% ropivacaine was injected, 1 mL at a time, up to 1.0 mL.kg-1. The ultrasound probe was moved cranially following the bulk flow of local anesthetics. Our primary outcome was the required volume of local anesthetics to reach each level of interlaminar space.

RESULTS

The dynamic flow tracking was available in 39 patients, and the required volume of the injectate to reach L5-S1, L4-L5, L3-L4, L2-L3, L1-L2, T12-L1, and T11-T12 was 0.125, 0.223, 0.381, 0.591, 0.797, 0.960, and 1.050 mL.kg-1, respectively. The required volume to reach the immediate upper spinal level was inconsistent across various spinal levels.

CONCLUSIONS

Local anesthetics of 0.223, 0.591, and 0.797 mL.kg-1 could provide sufficient analgesia for localized foot, knee, and hip surgeries, respectively. However, since the required volume of the local anesthetics could not be calculated linearly, the real-time dynamic flow tracking technique for the caudal epidural block is recommended in young pediatric patients.

TRIAL REGISTRATIONS

ClinicalTrials.gov (NCT04039295).

Comparison of preemptive and preventive intravenous acetaminophen on opioid consumption in pediatrics undergoing posterior spinal fusion surgery: a randomized controlled trial

Background

Posterior spinal fusion (PSF), commonly used for adolescent idiopathic scoliosis (AIS), causes severe postoperative pain. Intravenous (IV) administration of acetaminophen has shown promise for opioid-sparing analgesia; however, its analgesic effect and optimal timing for its standard use remain unclear. Our study aimed to evaluate the analgesic effect and optimal timing of IV acetaminophen administration in pediatric and adolescent patients undergoing PSF and requiring adequate pain control.

Methods

This prospective, randomized, triple-blind trial was conducted in patients aged 11-20 undergoing PSF. Participants were randomized into three groups: the preemptive group (received IV acetaminophen 15 mg/kg after anesthetic induction/before surgical incision), the preventive group (received IV acetaminophen 15 mg/kg at the end of surgery/before skin closure), and the placebo group. The primary outcome was cumulative opioid consumption during the first 24 h postoperatively.

Results

Among the 99 enrolled patients, the mean ± standard deviation (SD) amount of opioid consumption during the postoperative 24 h was 60.66 ± 23.84, 52.23 ± 22.43, and 66.70 ± 23.01 mg in the preemptive, preventive, and placebo groups, respectively (overall p = 0.043). A post hoc analysis revealed that the preventive group had significantly lower opioid consumption than the placebo group (p = 0.013). However, no significant differences between the groups were observed for the secondary outcomes.

Conclusions

The preventive administration of scheduled IV acetaminophen reduces cumulative opioid consumption without increasing the incidence of drug-induced adverse events in pediatric and adolescent patients undergoing PSF.

Effective remimazolam loading dose for adequate sedation in regional anesthesia

PURPOSE

Remimazolam is a novel ultrashort-acting sedative considered appropriate for continuous infusion during surgical procedures. Nevertheless, information regarding its loading dose for sedation during surgery is limited. We aimed to determine the 90% effective dose (ED90) of the remimazolam loading dose for sedation in patients undergoing limb surgery under regional anesthesia.

METHODS

We included 50 patients aged 19-80 yr undergoing limb surgery under regional anesthesia. After regional anesthesia, remimazolam besylate was administered at the assigned dose. For ten minutes after the initiation of loading, the level of sedation was evaluated using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale. The primary outcome was the ED90 based on whether patients reached a MOAA/S score of ≤ 3 points (loss of response to verbal command) within ten minutes. The secondary outcomes were the ED50 and the estimated effect site and plasma concentration at the time of achieving successful sedation.

RESULTS

In total, 49 patients were included in the final analysis, and adequate sedation with the assigned loading dose was successful in 42 patients. The log-logistic function showed that the ED90 and ED50 were 0.617 mg·kg-1·hr-1 (95% confidence interval [CI], 0.511 to 0.722; 98% CI, 0.492 to 0.741) and 0.438 mg·kg-1·hr-1 (95% CI, 0.335 to 0.541; 98% CI, 0.315 to 0.560), respectively.

CONCLUSION

The ED90 of the remimazolam loading dose to achieve adequate sedation in patients undergoing limb surgery under regional anesthesia was 0.617 mg·kg-1·hr-1 (95% CI, 0.511 to 0.722; 98% CI, 0.492 to 0.741).

STUDY REGISTRATION

ClinicalTrials.gov (NCT05340335); first posted 22 April 2022.

Association between Sarcopenia and Survival in Patients Undergoing Gamma Knife Surgery for Brain Metastasis from Breast Cancer: A Retrospective Single-centre Cohort Study

AIMS

Many recent studies related to cancer surgery have reported that sarcopenia influences mortality in surgical patients. However, few comprehensive studies have examined the associations between sarcopenia and short- and long-term surgical outcomes of metastatic cancer, especially breast cancer with brain metastasis. In the present study, we investigated the association between sarcopenia and mortality in patients who underwent gamma knife radiosurgery (GKRS) for brain metastasis with breast cancer.

MATERIALS AND METHODS

This retrospective study analysed 157 patients who underwent GKRS for brain metastasis with breast cancer between January 2014 and December 2018. A Cox regression analysis was carried out to evaluate the association between sarcopenia and mortality at 90 days, 180 days, 1 year, 3 years and the overall period.

RESULTS

In the Cox regression analysis, sarcopenia was significantly associated with high 90-day mortality (adjusted hazard ratio 3.46, 95% confidence interval 1.24-9.67, P = 0.018), 180-day mortality (adjusted hazard ratio 2.67, 95% confidence interval 1.37-5.22, P = 0.004), 1-year mortality (adjusted hazard ratio 2.39, 95% confidence interval 1.42-4.02, P = 0.001), 3-year mortality (adjusted hazard ratio 2.39, 95% confidence interval 1.53-3.74, P < 0.001) and overall mortality (adjusted hazard ratio 2.11, 95% confidence interval 1.37-3.26, P < 0.001).

CONCLUSION

Sarcopenia could be a risk factor for short- and long-term mortality in patients undergoing GKRS for brain metastasis from breast cancer.

Norepinephrine prevents hypotension in older patients under spinal anesthesia with intravenous propofol sedation: a randomized controlled trial

Reducing hypotension is crucial as hypotension is the most common side effect of spinal anesthesia, and in older patients with various comorbidities, it can lead to fatality. We hypothesized that continuous infusion of norepinephrine could effectively prevent hypotension in older patients undergoing hip surgery under spinal anesthesia with propofol sedation. The study randomly assigned patients aged ≥ 70 years to either a control (Group C, n = 35) or a norepinephrine group (Group N, n = 35). After spinal anesthesia, continuous infusion of propofol and normal saline or norepinephrine was initiated. The number of hypotensive episodes, the primary outcome, as well as other intraoperative hemodynamic events and postoperative complications were compared. In total, 67 patients were included in the final analysis. The number of hypotensive episodes was significantly higher in Group C than in Group N (p < 0.001). Furthermore, Group C required a greater amount of fluid to maintain normovolemia (p = 0.008) and showed less urine output (p = 0.019). However, there was no difference in postoperative complications between the two groups. Continuous intravenous infusion of prophylactic norepinephrine prevented hypotensive episodes, reduced the requirement of fluid, and increased the urine output in older patients undergoing unilateral hip surgery under spinal anesthesia with propofol sedation.Clinical trial registration number: KCT0005046 ( https://cris.nih.go.kr ). IRB number: 2020-0533 (Institutional Review Board of Asan Medical Center, approval date: 13/APR/2020).

Comparison of the Analgesic Efficacy between Arthroscopically Placed Continuous Suprascapular Nerve Block and Ultrasound-guided Continuous Superior Trunk Block: A Double-blinded Randomized Controlled Trial

BACKGROUND

Single-shot suprascapular nerve block and superior trunk block have been reported to provide a noninferior analgesic effect after shoulder surgery with a lesser incidence of hemidiaphragmatic paresis compared with interscalene brachial plexus block. This study hypothesized that continuous suprascapular nerve block provides noninferior analgesia with minimal effects on diaphragmatic movement compared with continuous superior trunk block in patients undergoing arthroscopic shoulder surgery.

METHODS

100 patients were randomized undergoing arthroscopic shoulder surgery between December 2020 and October 2021 into continuous suprascapular nerve block and continuous superior trunk block groups. Before the surgery, patients received either a single-shot superior trunk block or subomohyoid suprascapular nerve block. Thereafter, a superior trunk catheter was inserted by anesthesiologists in patients in the continuous superior trunk block group, and a posterior suprascapular nerve catheter was inserted with arthroscopic assistance during the surgery by surgeon in the continuous suprascapular nerve block group. The primary outcome was the postoperative pain score at postoperative 24 h, and the incidence of hemidiaphragmatic paresis was also compared.

RESULTS

Overall, 98 patients were included in the final analysis. The worst and resting pain scores at postoperative 24 h in the continuous suprascapular nerve block group were inferior compared with those in the continuous superior trunk block group in the test with a noninferiority margin of 1 (worst pain score: mean difference, 0.9; 95% CI, 0.1 to 1.7; resting pain score: mean difference, 0.5; 95% CI, 0.0 to 1.0). However, the continuous suprascapular nerve block group had a significantly lower incidence of hemidiaphragmatic paresis at postoperative 24 h than the continuous superior trunk block group.

CONCLUSIONS

Continuous suprascapular nerve block provides statistically inferior analgesia compared to the continuous superior trunk block; however, the continuous suprascapular nerve block had a minimal effect on the phrenic nerve function.

EDITOR’S PERSPECTIVE

Predicting Epidural Space Spread Using Ultrasound Color Doppler Imaging in Interlaminar Epidural Steroid Injection: A Prospective Observational Study

BACKGROUND

While the use of fluoroscopy-guided transforaminal epidural steroid injection (TFESI) to help spread the injectate toward the ventral side has increased, this procedure has a radiation risk. Recently, ultrasound has been widely used in the medical field; among ultrasound methods, color Doppler is useful for predicting the direction of the injectate.

OBJECTIVE

This study describes a novel technique employing color Doppler to help predict epidural space spread in interlaminar epidural steroid injection (ILESI).

STUDY DESIGN

Prospective observational study.

SETTING

The study took place at a single pain clinic within a medical center in Jeonju, Republic of Korea.

METHODS

We enrolled 35 patients scheduled for lumbar epidural steroid injection (ESI).  Ultrasound-guided epidural lateral parasagittal interlaminar injection was performed and real-time images using color Doppler were recorded during injections of 5 mL of 0.1% ropivacaine containing contrast dye with dexamethasone 5 mg (1 mL). Fluoroscopy-guided TFESI was performed if it was difficult to perform the procedure based on ultrasound images.

RESULTS

The analysis included 30 images from 30 patients. The observed sensitivity, specificity, positive predictive value, and negative predictive values of the ultrasound color Doppler were 100%, 89.5%, 84.6%, and 100%, respectively. The agreement with ultrasound color Doppler was 93.3%.

LIMITATIONS

The sample size was relatively small.

CONCLUSION

The main advantage of ultrasound-guided ILESI is the lack of radiation exposure and contrast medium requirement. Color Doppler may be a reliable imaging modality to predict epidural space spread during ultrasound-guided ILESI. It is worth predicting the spread in the anterior epidural space (AES) by first attempting ultrasound-guided ESI. If the injectate has not spread to the AES, fluoroscopy-guided TFESI may be a good option after confirming improvement of the patient's symptoms.

Short-term high-dose intravenous iron reduced peri-operative transfusion after staggered bilateral total knee arthroplasty: A retrospective cohort study

BACKGROUND AND OBJECTIVES

Staggered bilateral total knee arthroplasty, two procedures performed 4-7 days apart during a single hospitalization, has an increased risk of blood transfusion. This observational study aimed to evaluate whether immediate post-operative single, high-dose intravenous iron supplementation could reduce transfusion requirements and facilitate anaemia recovery in patients.

MATERIALS AND METHODS

We retrospectively analysed 131 patients who underwent staggered bilateral total knee arthroplasty. The ferric carboxymaltose (FCM) group received 1000 mg of FCM after the first operation. The non-FCM group did not receive intravenous iron. The transfusion rate and post-operative complications were compared between the groups. The anaemia rate was evaluated pre-operatively, during hospitalization, and 5 weeks after the second total knee arthroplasty.

RESULTS

The FCM group comprised 78 patients (59.5%). The rate (21.8% vs. 47.2%, p = 0.004) and amount of transfusion (0 [0-2] vs. 0 [0-0], p = 0.001) was significantly lower in the FCM group than in the non-FCM group. Although both groups' pre-operative haemoglobin concentrations were not significantly different, the FCM group demonstrated higher haemoglobin values 5 weeks post surgery (12.25 ± 0.83 mg/dl vs. 11.48 ± 1.36 mg/dl, p < 0.001). More non-FCM patients developed moderate to severe anaemia at 5 weeks post surgery (p < 0.001). The mortality and complication rates were not significantly different.

CONCLUSIONS

Immediate post-operative, high-dose, intravenous iron treatment may contribute to reduced transfusion rates, facilitate haemoglobin recovery after staggered bilateral total knee arthroplasty, and minimize the development of moderate to severe anaemia.

Postoperative Pain Control After Arthroscopic Rotator Cuff Repair: Arthroscopy-Guided Continuous Suprascapular Nerve Block Versus Ultrasound-Guided Continuous Interscalene Block

PURPOSE

To compare the clinical efficacy and safety of arthroscopy-guided continuous suprascapular nerve block and ultrasound-guided continuous interscalene block in postoperative analgesia in patients undergoing arthroscopic rotator cuff repair.

METHODS

A prospective study was performed between March and November 2020. In total, 76 patients were enrolled and divided into 2 groups: in the 38 patients of group 1 (arthroscopy-guided continuous suprascapular nerve block), an indwelling catheter was introduced via the Neviaser portal under arthroscopic view before closing the portal at the end of the surgery; and in the 38 patients of group 2 (ultrasound-guided continuous interscalene block), an indwelling catheter was inserted and directed toward the interscalene brachial plexus prior to the surgery under ultrasound guidance. The primary outcome was the pain score measured by the visual analog scale at postoperative 24 hours during admission. Comparisons were conducted at different time points (postoperative 4, 8, 24, and 48 hours). The secondary outcome was any of these events: neurologic complications, such as sensory/motor change in the upper extremities; hemidiaphragmatic paresis; dyspnea; dysphonia; and Horner's syndrome. Opioid usage until postoperative 3 weeks was compared between the groups.

RESULTS

The visual analog scale scores in groups 1 and 2 were comparable at each postoperative time point (analysis of variance, P = .919; trends, P = .132). Neurologic deficits were more common in group 2 than in group 1 (8 vs 32 patients, P < .001). Decreased excursion of the diaphragm was more common in group 2 (partial or complete paresis of the hemidiaphragm: 1 vs 29 patients, P < .001). Opioid consumption was similar in both groups (morphine milligram equivalents per kilogram; 1.75 vs 1.55, P = .195).

CONCLUSIONS

Our findings show that arthroscopy-guided continuous suprascapular nerve block is not inferior to ultrasound-guided continuous interscalene block for postoperative pain control after arthroscopic rotator cuff repair while showing fewer temporary neurologic complications.

LEVEL OF EVIDENCE

Level II, prospective cohort study, interventional study.

Immediate intravenous iron administration improves anaemia recovery following total knee arthroplasty: A propensity-matched analysis

BACKGROUND AND OBJECTIVES

Patients who undergo total knee arthroplasty (TKA) have a risk of postoperative anaemia. This observational study evaluated whether single-dose intravenous ferric carboxymaltose (FCM) administered immediately after TKA facilitates the correction of anaemia.

MATERIALS AND METHODS

We retrospectively analysed 722 patients who underwent primary TKA. The FCM group receiving 1000 mg intravenous FCM within one postoperative hour was compared with the non-FCM group that did not receive the medication. A propensity score matching with multiple logistic regression analysis was used to minimize intergroup differences in the baseline characteristics and postoperative blood loss. The rate and severity of postoperative anaemia were compared between the groups, along with haemoglobin (Hb) value, transfusion rate and complications.

RESULTS

After propensity score matching, 231 patients were included in each group. In the FCM group, the rate of anaemia at postoperative day (POD) 7 (p = 0.021) and postoperative week (POW) 5 (p < 0.001) and the transfusion rate were significantly lower (p = 0.008). The rate of moderate to severe anaemia at POW-5 was also significantly lower in the FCM group (p < 0.001). In patients without preoperative anaemia (n = 322), the transfusion rate and rate and severity of anaemia at POD-7 and POW-5 were significantly lower in the FCM group than in the non-FCM group.

CONCLUSION

Postoperative intravenous FCM administration facilitated recovery of surgery-related anaemia by improving Hb and may reduce the need for transfusion in TKA patients. Preoperative non-anaemic patients could also benefit from accelerated recovery by intravenous iron treatment.

Real-time ultrasound guided thoracic epidural catheterization: a technical review

Thoracic epidural analgesia is known to have superior perioperative pain control over intravenous opioid analgesia in open abdominal surgery and is an essential enhanced recovery after surgery component in major abdominal surgeries. Recently, the ultrasound-guided thoracic epidural catheter placement (TECP) technique has drawn attention as an alternative for the traditional landmark palpation-based TECP or fluoroscopic-guided TECP technique due to the equipment's improvement and increased popularity. However, only a small number of studies have introduced the advantages and usefulness of ultrasound-guided TECP. Moreover, a certain level of ultrasound-guided in-plane technique is required to perform this technique. Thus, to apply ultrasound-guided TECP correctly and reduce the likelihood of side effects and complications, the practitioner must have a thorough understanding of the anatomical region, optimal block positioning, device selection, and management. In this technical review, the authors have compared the advantages and disadvantages of ultrasound-guided TECP to traditional techniques and described its technical aspects from patient positioning, ultrasound probe selection and scanning, needle insertion under ultrasound guidance, and successful thoracic epidural catheter insertion confirmation through ultrasound imaging. Additionally, the recommended epidural catheter tip placement level with the extent of its injectate epidural spread is further described in this review in reference to a recent prospective study published by the authors.

Bilateral high thoracic continuous erector spinae plane blocks for postoperative analgesia in a posterior cervical fusion

Posterior decompression and instrumentation of the cervical spine are associated with severe postoperative pain due to extensive soft tissue and muscle dissection during the surgery. In this case series, we describe bilateral continuous cervical erector spinae plane block (CESPB) placed at T1-2 through the thoracic erector spinae plane. A series of 4 patients underwent posterior cervical decompression and stabilization for various surgical indications. The CESPB block provides intense analgesia with low requirements of anesthetic drugs in the perioperative period and opioid-free analgesia in the postoperative period. The spread of local anesthetic was studied by performing CT contrast studies after obtaining informed consent.

Ultrasound-Guided Anterior Approach to a Sciatic Nerve Block: Influence of Lower Limb Positioning on the Visibility and Depth of the Sciatic Nerve

OBJECTIVES

We aimed to identify the optimal lower limb position for an ultrasound (US)-guided anterior approach to a sciatic nerve block.

METHODS

We included 45 patients who met the following criteria: American Society of Anesthesiologists physical status of 1 to 3, age between 18 and 80 years, and scheduled to undergo knee surgery that required a sciatic nerve block. The lower limbs of each patient were placed in the following 4 positions: N, neutral; ER, external rotation of the hip (angle, 45°); ER/F15, ER (angle, 45°) and flexion (angle, 15°) of the hip; and ER/F45, ER (angle, 45°) and F (angle, 45°) of the hip. An investigator acquired US scans of the sciatic nerve in each position, and the visibility score and depth of the sciatic nerve from the skin were analyzed.

RESULTS

The visibility scores were significantly higher in positions ER/F15 and ER/F45 than in positions ER and N (P < .0001). However, there was no difference between the visibility scores in positions ER/F15 and ER/F45 (P = .0959). The depth of the sciatic nerve from the skin decreased with ER and an increase in the F angle of the hip (overall P < .0001).

CONCLUSIONS

Based on the visibility score and depth from the skin, ER of the hip to 45° with a greater F angle (45° versus 15°) of the hip appears to be the optimal position for an US-guided anterior approach to a sciatic nerve block.

Remote Ischemic Preconditioning and Diazoxide Protect from Hepatic Ischemic Reperfusion Injury by Inhibiting HMGB1-Induced TLR4/MyD88/NF-κB Signaling

Remote ischemic preconditioning (RIPC) is known to have a protective effect against hepatic ischemia-reperfusion (IR) injury in animal models. However, the underlying mechanism of action is not clearly understood. This study examined the effectiveness of RIPC in a mouse model of hepatic IR and aimed to clarify the mechanism and relationship of the ATP-sensitive potassium channel (K_ATP) and HMGB1-induced TLR4/MyD88/NF-κB signaling. C57BL/6 male mice were separated into six groups: (i) sham-operated control, (ii) IR, (iii) RIPC+IR, (iv) RIPC+IR+glyburide (K_ATP blocker), (v) RIPC+IR+diazoxide (K_ATP opener), and (vi) RIPC+IR+diazoxide+glyburide groups. Histological changes, including hepatic ischemia injury, were assessed. The levels of circulating liver enzymes and inflammatory cytokines were measured. Levels of apoptotic proteins, proinflammatory factors (TLR4, HMGB1, MyD88, and NF-κB), and IκBα were measured by Western blot and mRNA levels of proinflammatory cytokine factors were determined by RT-PCR. RIPC significantly decreased hepatic ischemic injury, inflammatory cytokine levels, and liver enzymes compared to the corresponding values observed in the IR mouse model. The K_ATP opener diazoxide + RIPC significantly reduced hepatic IR injury demonstrating an additive effect on protection against hepatic IR injury. The protective effect appeared to be related to the opening of K_ATP, which inhibited HMGB1-induced TRL4/MyD88/NF-kB signaling.

Effect of Anesthetic Technique on the Occurrence of Acute Kidney Injury after Total Knee Arthroplasty

Recent studies have reported the advantages of spinal anesthesia over general anesthesia in orthopedic patients. However, little is known about the relationship between acute kidney injury (AKI) after total knee arthroplasty (TKA) and anesthetic technique. This study aimed to identify the influence of anesthetic technique on AKI in TKA patients. We also evaluated whether the choice of anesthetic technique affected other clinical outcomes. We retrospectively reviewed medical records of patients who underwent TKA between January 2008 and August 2016. Perioperative data were obtained and analyzed. To reduce the influence of potential confounding factors, propensity score (PS) analysis was performed. A total of 2809 patients and 2987 cases of TKA were included in this study. A crude analysis of the total set demonstrated a significantly lower risk of AKI in the spinal anesthesia group. After PS matching, the spinal anesthesia group showed a tendency for reduced AKI, without statistical significance. Furthermore, the spinal anesthesia group showed a lower risk of pulmonary and vascular complications, and shortened hospital stay after PS matching. In TKA patients, spinal anesthesia had a tendency to reduce AKI. Moreover, spinal anesthesia not only reduced vascular and pulmonary complications, but also shortened hospital stay.

Staggered Rather Than Staged or Simultaneous Surgical Strategy May Reduce the Risk of Acute Kidney Injury in Patients Undergoing Bilateral TKA

BACKGROUND

The strategy for bilateral total knee arthroplasty (TKA) depends on the timing of surgery for each knee. The purpose of this study was to determine whether the type of surgical strategy for bilateral TKA (staggered, staged, or simultaneous) influences the incidence of acute kidney injury (AKI) and related complications.

METHODS

Enrolled patients from a single tertiary teaching hospital were divided into 3 groups according to the surgical strategy for bilateral TKA: staggered (≤7 days between the first and second procedure; n = 368), staged (8 days to 1 year between the first and second procedure; n = 265), or simultaneous (n = 820). The incidence of AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria was assessed. The rates of major postoperative complications, major adverse cardiovascular and cerebral events, intensive care unit (ICU) admissions, and mortality were also evaluated. To reduce the influence of possible confounding factors, inverse probability of treatment weighting based on propensity-score analysis was used.

RESULTS

The primary outcome was the incidence of AKI according to surgical strategy. The staggered group had a lower rate of AKI compared with the other 2 groups (p < 0.001): 2.4% (9 of 368 patients), 6.0% (16 of 265), and 11.2% (92 of 820) in the staggered, staged, and simultaneous groups, respectively.

CONCLUSIONS

The type of bilateral TKA strategy was an independent risk factor for the development of AKI. The assessment of additional risk factors for the development of AKI is essential before deciding on surgical strategy.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Predicting massive transfusion in adolescent idiopathic scoliosis patients undergoing corrective surgery: Association of preoperative radiographic findings

Corrective surgery with a posterior approach for adolescent idiopathic scoliosis (AIS) is often accompanied by considerable bleeding. Massive transfusion after excessive hemorrhage is associated with complications such as hypothermia, coagulopathy, and acid-base imbalance. Therefore, prediction and prevention of massive transfusion are necessary to improve the clinical outcome of AIS patients. We aimed to identify the factors associated with massive transfusion in AIS patients undergoing corrective surgery. We also evaluated the clinical outcomes after massive transfusion.We included and analyzed AIS patients who underwent corrective surgery with a posterior approach from January 2008 to February 2015. We retrospectively reviewed the electronic medical records of 765 consecutive patients. We performed multivariable logistic regression analysis to assess the factors related to massive transfusion. Furthermore, we compared the effects of massive transfusion on clinical outcomes, including postoperative morbidity and hospital stay.Of 765 patients, 74 (9.7%) received massive transfusion. Body mass index (odds ratio [OR] 0.782, 95% confidence interval [CI] 0.691-0.885, P < .001) and the number of fused vertebrae (OR 1.322, 95% CI 1.027-1.703, P = .03) were associated with massive transfusion. In the comparison among the different Lenke curve types, Lenke type 4 showed the highest prevalence of massive transfusion. Patients in the massive transfusion group showed a higher incidence rate of postoperative morbidity and prolonged hospital stay.Massive transfusion was required in 9.7% of AIS patients who underwent corrective surgery with a posterior approach. A lower body mass index and higher number of fused vertebrae were associated with massive transfusion. Massive transfusion is related to poor clinical outcomes in AIS patients.

The Antiallodynic Effects of Nefopam Are Mediated by the Adenosine Triphosphate-Sensitive Potassium Channel in a Neuropathic Pain Model

BACKGROUND

Nefopam hydrochloride is a centrally acting compound that induces antinociceptive and antihyperalgesic properties in neuropathic pain models. Previous reports have shown that activation of adenosine triphosphate (ATP)-sensitive and calcium-activated potassium (KATP and KCa2+) channels has antiallodynic effects in neuropathic pain. In the present study, we evaluated the relationship between potassium channels and nefopam to determine whether the antiallodynic effects of nefopam are mediated by potassium channels in a neuropathic pain model.

METHODS

Mechanical allodynia was induced by spinal nerve ligation (SNL) in rats, and the paw withdrawal threshold (PWT) was evaluated by the use of von Frey filaments. Nefopam was administered intraperitoneally before or after SNL. We assessed the relationship between nefopam and intrathecal injection of the KCa2+ channel antagonists apamin and charybdotoxin, and the KATP channel blocker glibenclamide to assess their abilities to reverse the antiallodynic effects of nefopam. In addition, we evaluated whether the KATP channel opener pinacidil had antiallodynic effects and promoted the antiallodynic effects of nefopam.

RESULTS

Administration of nefopam before and after SNL induced significant antiallodynic effects (P < .01, respectively), which were significantly reduced by glibenclamide (P < .01). Pinacidil improved the antiallodynic effects of nefopam (P < .01); however, apamin and charybdotoxin had little effects on the antiallodynic properties of nefopam.

CONCLUSIONS

The antiallodynic effects of nefopam are increased by a KATP channel agonist and reversed by a KATP channel antagonist. These data suggest that the KATP channel is involved in the antiallodynic effects of nefopam in a neuropathic pain model.

Efficacy of Adjuvant 10% Hypertonic Saline in Transforaminal Epidural Steroid Injection: A Retrospective Analysis

Background: Chronic lower back pain with or without radiculopathy represents an important medical, social, and economic problem. Many treatment modalities and techniques, including surgery and epidural administration of steroids, have been used to manage this pain. Hypertonic saline, which has been used as an adjunct to percutaneous epidural adhesiolysis, can also be injected via a transforaminal approach in expectation of longer-lasting effects. Objectives: This study aimed to determine the effect of adding hypertonic saline to conventional transforaminal epidural steroid injections (TFEI) to provide pain relief for chronic radiculopathy patients. Study Design: A retrospective study. Setting: Pain clinic of a university hospital. Methods: Between January 2010 and December 2013, the medical records of 246 patients (94 in the hypertonic group, 153 in the control group) who received transforaminal epidural block were reviewed and analyzed. The hypertonic group received 10% sodium chloride solution added to lidocaine, triamcinolone, and hyaluronidase. Outcomes on pain reduction were measured using a numerical rating scale (NRS) and the responder rate at baseline, one, 3, and 6 months after procedure. Results: The estimated difference in NRS scores from baseline throughout a 6-month followup period in the hypertonic group were significantly higher (P = 0.0003). The proportion of substantial responders (41.9% vs. 34.6% at one month, 40.9% vs. 26.8% at 3 months, and 33.3% vs. 14.4% at 6 months, respectively, P = 0.0058) and substantial/moderate responders (71.0% vs. 58.8% at one month, 65.6% vs. 40.4% at 3 months, and 48.4% vs. 20.3% at 6 months, respectively, P < 0.0001) were significantly higher in the hypertonic group. The Oswestry disability index (ODI) was not different between the groups (P = 0.2697). Limitations: Retrospective design without a control group. Conclusions: Hypertonic saline provides more superior and longer lasting pain relieving effects when added to TFEIs. Key words: Back pain, epidural injections, epidural steroids, hypertonic saline, lumbar, radiculopathy, transforaminal

Efficacy of Adjuvant 10% Hypertonic Saline in Transforaminal Epidural Steroid Injection: A Retrospective Analysis

BACKGROUND

Chronic lower back pain with or without radiculopathy represents an important medical, social, and economic problem. Many treatment modalities and techniques, including surgery and epidural administration of steroids, have been used to manage this pain. Hypertonic saline, which has been used as an adjunct to percutaneous epidural adhesiolysis, can also be injected via a transforaminal approach in expectation of longer-lasting effects.

OBJECTIVES

This study aimed to determine the effect of adding hypertonic saline to conventional transforaminal epidural steroid injections (TFEI) to provide pain relief for chronic radiculopathy patients.

STUDY DESIGN

A retrospective study.

SETTING

Pain clinic of a university hospital.

METHODS

Between January 2010 and December 2013, the medical records of 246 patients (94 in the hypertonic group, 153 in the control group) who received transforaminal epidural block were reviewed and analyzed. The hypertonic group received 10% sodium chloride solution added to lidocaine, triamcinolone, and hyaluronidase. Outcomes on pain reduction were measured using a numerical rating scale (NRS) and the responder rate at baseline, one, 3, and 6 months after procedure.

RESULTS

The estimated difference in NRS scores from baseline throughout a 6-month follow-up period in the hypertonic group were significantly higher (P = 0.0003). The proportion of substantial responders (41.9% vs. 34.6% at one month, 40.9% vs. 26.8% at 3 months, and 33.3% vs. 14.4% at 6 months, respectively, P = 0.0058) and substantial/moderate responders (71.0% vs. 58.8% at one month, 65.6% vs. 40.4% at 3 months, and 48.4% vs. 20.3% at 6 months, respectively, P < 0.0001) were significantly higher in the hypertonic group. The Oswestry disability index (ODI) was not different between the groups (P = 0.2697).

LIMITATIONS

Retrospective design without a control group.

CONCLUSIONS

Hypertonic saline provides more superior and longer lasting pain relieving effects when added to TFEIs.Key words: Back pain, epidural injections, epidural steroids, hypertonic saline, lumbar, radiculopathy, transforaminal.

The neuromuscular effects of rocuronium under sevoflurane-remifentanil or propofol-remifentanil anesthesia: a randomized clinical comparative study in an Asian population

Background

We conducted a prospective, randomized, multicenter study to evaluate the differences in the blocking effect of different doses of rocuronium between sevoflurane- or propofol-remifentanil anesthesia in an Asian population.

Methods

A total of 368 ASA I–II patients was enrolled. Anesthesia was induced with 2.0 mg/kg propofol and 0.1 μg/kg/min remifentanil (TIVA) or 5.0 vol.% sevoflurane with 0.1 μg/kg/min remifentanil (SEVO). Tracheal intubation was facilitated at 180 s after the administration of rocuronium at 0.3, 0.6, or 0.9 mg/kg and then intubation condition was evaluated. The time to maximum block and recovery profile were monitored by TOF stimulation of the ulnar nerve and by recording the adductor pollicis response using acceleromyography.

Results

The numbers of patients with clinically acceptable intubation conditions were 41, 82, and 97 % (TIVA) and 34, 85, and 90 % (SEVO) at each dose of rocuronium, respectively. There were no significant differences in the time to maximum block between groups at each rocuronium dose. There were significant differences in the recovery to a train-of-four ratio of 90 % between the groups: 42.7 (19.5), 74.8 (29.9), and 118.4 (35.1) min (TIVA) and 66.5 (39.3), 110.2 (43.5), and 144.4 (57.5) min (SEVO) at 0.3, 0.6, and 0.9 mg/kg, respectively (P < 0.001).

Conclusions

There are no significant differences in intubation conditions between propofol-remifentanil and sevoflurane-remifentanil anesthesia at the same dose of rocuronium. The type of anesthetic does not significantly influence the time to maximum block by rocuronium. Rocuronium at a dose of 0.9 mg/kg should be used for better intubation conditions with both anesthesia regimens in an Asian population.

Trial registration

UMIN-CTR Clinical Trial (http://www.umin.ac.jp/ctr/index.htm; UMIN#000007289; date of registration 14^th February 2012).

The preventive effect of resiniferatoxin on the development of cold hypersensitivity induced by spinal nerve ligation: involvement of TRPM8

BACKGROUND

Resiniferatoxin (RTX) is a potent analog of capsaicin and activates transient receptor potential (TRP) vanilloid type (TRPV) 1. In the current study, we investigated the preventive effect of perineural RTX on the development of cold hypersensitivity induced by spinal nerve ligation (SNL) in rats. Furthermore, we examined the association between the expression level of TRPV1, TRP ankyrin type (TRPA) 1 and TRP melastatin type (TRPM) 8 in the dorsal root ganglion (DRG) and cold hypersensitivity after SNL.

RESULTS

RTX pretreatment prevented the development of SNL-induced hypersensitivity to mechanical, thermal, and cold stimuli. Western blot analysis 4 weeks after RTX pretreatment showed that RTX pretreatment decreased the protein expression level of SNL-induced TRPM8, but not TRPV1 or TRPA1, in the DRG of SNL rats. Immunofluorescent analysis revealed that up-regulated TRPM8-stained neurons after SNL co-localized with neurofilament 200-positive neurons located in the DRG.

CONCLUSIONS

Pretreatment with perineural RTX significantly inhibits SNL-induced mechanical, thermal, and cold hypersensitivity. The antinociceptive effect of perineural RTX, especially on cold hypersensitivity, may be related to the suppression of TRPM8 expression in DRG.

Perineural pretreatment of bee venom attenuated the development of allodynia in the spinal nerve ligation injured neuropathic pain model; an experimental study

Background

Diluted bee venom (BV) is known to have anti-nociceptive and anti-inflammatory effects. We therefore assessed whether perineural bee venom pretreatment could attenuate the development of neuropathic pain in the spinal nerve ligation injured animal model.

Methods

Neuropathic pain was surgically induced in 30 male Sprague Dawley rats by ligation of the L5 and L6 spinal nerves, with 10 rats each treated with saline and 0.05 and 0.1 mg BV. Behavioral testing for mechanical, cold, and thermal allodynia was conducted on postoperative days 3 to 29. Three rats in each group and 9 sham operated rats were sacrificed on day 9, and the expression of transient receptor potential vanilloid type 1 (TRPV1), ankyrin type 1 (TRPA1), and melastatin type 8 (TRPM8) receptors in the ipsilateral L5 dorsal root ganglion was analyzed.

Results

The perineural administration of BV to the spinal nerves attenuated the development of mechanical, thermal, and cold allodynia, and the BV pretreatment reduced the expression of TRPV1, TRPA1, TRPM8 and c − Fos in the ipsilateral dorsal root ganglion.

Conclusion

The current study demonstrates that the perineural pretreatment with diluted bee venom before the induction of spinal nerve ligation significantly suppresses the development of neuropathic pain. Furthermore, this bee venom induced suppression was strongly related with the involvement of transient receptor potential family members.

Transforaminal hypertonic saline for the treatment of lumbar lateral canal stenosis: a double-blinded, randomized, active-control trial

BACKGROUND

Degenerative lumbar spinal stenosis is one of the most common causes of chronic lower back pain and radiculopathy. Spinal stenosis is anatomically classified as central and lateral spinal canal stenosis. Many treatment modalities and techniques, including surgery and epidural injection, have been used to manage the pain. However, the effect of hypertonic saline injection via the transforaminal approach has not yet been studied.

OBJECTIVES

The aim of this study is to determine the effect of adding hypertonic saline to conventional transforaminal epidural steroid injections (TFEI) to provide pain relief for chronic radiculopathy patients secondary to lateral canal spinal stenosis.

STUDY DESIGN

A double-blind, randomized, active-control trial.

SETTING

An interventional pain management practice in a hospital, Republic of Korea.

METHODS

Two groups: the hypertonic group received hypertonic saline combined with triamcinolone and the control group received normal saline combined with triamcinolone. A total of 68 patients were randomly allocated into either 2 groups by a computer-generated randomization program. Twenty-seven patients in the hypertonic group and 26 patients in the control group were assessed. A total of 53 patients were included in this analysis. Outcome measures were taken at baseline, one, 2, 3, 4, and 6 months post-procedure. The primary outcome measures included the numerical rating scale (NRS) and the proportion of substantial responders. The secondary outcome measures included the Oswestry disability index (ODI), the proportion of substantial and moderate responders, and patient satisfaction.

RESULTS

Transforaminal epidural injection of steroids, with or without the addition of 10% hypertonic saline, was effective and provided significant pain relief with the improvement of functional outcome within 4 months. The addition of hypertonic saline was superior in efficacy compared with conventional TFEI at 3 months follow-up. The differences in the absolute pain scores did not demonstrate statistical significance between the 2 groups. The reduction in pain intensity from the baseline was greater in the hypertonic group and demonstrated higher rates of satisfaction. The use of hypertonic saline also extended the duration of significant pain relief to 6 months compared with baseline.

LIMITATIONS

The lack of placebo group and small sample size.

CONCLUSION

Superior short-term pain relieving efficacy, but limited long-term effects of hypertonic saline, when added to TFEIs.

Effects of transforaminal balloon treatment in patients with lumbar foraminal stenosis: a randomized, controlled, double-blind trial

BACKGROUND

Lumbar spinal stenosis is a common condition in the elderly. Although balloon treatment is a well-known therapeutic method in specific pain conditions, applying the balloon treatment in patients with lumbar spinal stenosis is not yet well established.

OBJECTIVES

We tested the therapeutic effect of transforaminal balloon treatment with a Fogarty balloon catheter on body pain and functional performance in patients with severe lumbar spinal stenosis.

STUDY DESIGN

Prospective, randomized, double-blinded, active control trial.

SETTING

A tertiary, interventional pain management practice, specialty referral center.

METHODS

Sixty-two patients with refractory unilateral radiculopathy aggravated by walking were enrolled and randomly assigned to receive transforaminal steroid injection after transforaminal balloon treatment using a 3 Fr balloon catheter (n = 32) or the same procedure without balloon treatment (n = 30). The patients were prohibited from making any alterations to their medications during the 12 weeks of their follow-up period. After the first 12 weeks, the patients who had persistent symptoms or unbearable pain were allowed to increase the dose of analgesics or to receive additional interventional treatment.

OUTCOME ASSESSMENT

Visual analogue scale (VAS) pain scores for the leg and lower back, Oswestry disability index (ODI), and claudication distance were measured at 2, 4, 8, and 12 weeks post procedure. During the 52 weeks of the overall follow-up period, the patients achieving ≥ 50% leg pain relief without additional treatment or increasing the dose of analgesics were evaluated.

RESULTS

Significant improvement occurred compared to baseline in VAS (P < 0.001), ODI (P < 0.001), and claudication distance (P < 0.001) in the balloon group during the overall follow-up period, whereas the improvement in ODI (P < 0.05) and claudication distance (P < 0.05) in the control group persisted for 8 weeks. The balloon group showed better improvement in leg VAS (P < 0.05), ODI (P < 0.05), and claudication distance (P < 0.05) than the control group at all post-procedure assessment points. Kaplan-Meier analysis of the duration of the patients achieving ≥ 50% leg pain relief without additional treatment or increasing the dose of analgesics showed a significant intergroup difference between the balloon and control (P = 0.003) groups. Six patients (18.8%) in balloon group maintained ≥ 50% pain relief for 52 weeks whereas no patient (0%) did in control group.

LIMITATIONS

Our study is an active-controlled randomized design with a relatively small number of patients.

CONCLUSION

Transforaminal balloon treatment leads to both significant pain relief and functional improvement in a subset of patients with refractory spinal stenosis. INSTITUTIONAL REVIEW: This study was approved by the Institutional Review Board of the Asan Medical Center.

Effect of ethyl pyruvate on Paclitaxel-induced neuropathic pain in rats

Background

Although paclitaxel is a widely used chemotherapeutic agent for the treatment of solid cancers, side effects such as neuropathic pain lead to poor compliance and discontinuation of the therapy. Ethyl pyruvate (EP) is known to have analgesic effects in several pain models and may inhibit apoptosis. The present study was designed to investigate the analgesic effects of EP on mechanical allodynia and apoptosis in dorsal root ganglion (DRG) cells after paclitaxel administration.

Methods

Rats were randomly divided into 3 groups: 1) a control group, which received only vehicle; 2) a paclitaxel group, which received paclitaxel; and 3) an EP group, which received EP after paclitaxel administration. Mechanical allodynia was tested before and at 7 and 14 days after final paclitaxel administration. Fourteen days after paclitaxel treatment, DRG apoptosis was determined by activated caspase-3 immunoreactivity (IR).

Results

Post-treatment with EP did not significantly affect paclitaxel-induced allodynia, although it tended to slightly reduce sensitivities to mechanical stimuli after paclitaxel administration. After paclitaxel administration, an increase in caspase-3 IR in DRG cells was observed, which was co-localized with NF200-positive myelinated neurons. Post-treatment with EP decreased the paclitaxel-induced caspase-3 IR. Paclitaxel administration or post-treatment with EP did not alter the glial fibrillary acidic protein IRs in DRG cells.

Conclusions

Inhibition of apoptosis in DRG neurons by EP may not be critical in paclitaxel-induced mechanical allodynia.

Preconsent video-assisted instruction improves the comprehension and satisfaction in elderly patient visiting pain clinic

BACKGROUND

Elderly patients visiting pain clinic may be at greater risk of misunderstanding the explanation because of age-related cognitive decline. Video instruction may provide a consistent from of teaching in a visual and realistic manner. We evaluated the effect of educational video on the patient understanding and satisfaction in a group of geriatric patients visiting pain clinic.

METHODS

Ninety two patients aged more than 60 years old who were scheduled for transforaminal epidural block were recruited. After exposure to either video or paper instruction process, each patient was asked 5-item comprehension questions, overall satisfaction and preference question. During follow-up period, number of outpatient referral-line call for further explanation was counted.

RESULTS

We observed significantly better comprehension in the video education compared with paper instruction (P < 0.001). Patient satisfaction was also higher in the video group (P = 0.015), and patients visiting pain clinic were more preferred video instruction (P < 0.001). Proportion of referral-line call for further explanation were similar (P = 0.302).

CONCLUSIONS

Video approach to instruction process before consent improves treatment comprehension in geriatric patient visiting pain clinic.

An alternative approach to needle placement in cervicothoracic epidural injections

The use of fluoroscopy guidance together with the loss of resistance technique during epidural injections has been advocated lately; moreover, epidural injections in the absence of fluoroscopic guidance have a high rate of inaccurate needle-tip placement during the injections. However, the approach to the lower cervical and upper thoracic epidural space may be challenging due to its obscure lateral fluoroscopic views from overlying normal tissue structures. In this case, we report an alternative oblique C-arm fluoroscopy guided view approach to supplement the standard anterior-posterior and lateral fluoroscopic views to facilitate successful needle placement and precise anatomical localization of the epidural space.

Effect of pre-exposure to sevoflurane on the bispectral index in women undergoing Caesarean delivery under general anaesthesia

BACKGROUND

Patients undergoing Caesarean delivery under inhalation anaesthesia are at a high risk of awareness, especially in the period before delivery. We assessed the effects of pre-exposure to sevoflurane on the bispectral index (BIS) in the interval before delivery.

METHODS

Sixty-four patients undergoing elective Caesarean delivery were randomly assigned to receive 1.0-1.1 vol% (control 1) or 1.2-1.3 vol% (control 2) end-tidal sevoflurane, or the same concentrations of end-tidal sevoflurane combined with pre-exposure to 1 vol% sevoflurane for the last 1 min of the preoxygenation period (the preSevo 1 and preSevo 2 groups, respectively). We assessed BIS values, arterial pressure, and heart rate at the time of induction; before intubation; and upon skin incision, uterine incision, and delivery. We also determined the maternal incidence of intraoperative awareness and the neonatal Apgar scores, and conducted umbilical blood gas analysis.

RESULTS

At skin incision, BIS values were significantly lower in the preSevo 1 group than in the control 1 group [50 (13) vs 72 (8), P<0.001] and in the preSevo 2 group than in the control 2 group [44 (11) vs 67 (10), P<0.001]. The mean BIS values in the preSevo 1 and 2 groups were maintained below 60 in the period before delivery. No other parameter differed among groups, and no patient exhibited intraoperative awareness.

CONCLUSIONS

Pre-exposure to low concentrations of sevoflurane reduced BIS values in the interval before delivery, suggesting that this approach may reduce the risk of maternal awareness. Clinical Research Information Service (code KCT0000069, http://cris.cdc.go.kr).

Clinical experiences of transforaminal balloon decompression for patients with spinal stenosis

Lumbar spinal stenosis is a commonly treated with epidural injections of local anesthetics and corticosteroids, however, these therapies may relieve leg pain for weeks to months but do not influence functional status. Furthermore, the majority of patients report no substantial symptom change over the repeated treatment. Utilizing balloon catheters, we successfully treated with three patients who complained persistent symptoms despite repeated conventional steroid injections. Our results suggest that transforaminal decompression using a balloon catheter may have potential in the nonsurgical treatment of spinal stenosis by modifying the underlying pathophysiology.

Value of Bone Scintigraphy and Single Photon Emission Computed Tomography (SPECT) in Lumbar Facet Disease and Prediction of Short-term Outcome of Ultrasound Guided Medial Branch Block with Bone SPECT

Background

Facet joint disease plays a major role in axial low-back pain. Few diagnostic tests and imaging methods for identifying this condition exist. Single photon emission computed tomography (SPECT) is reported that it has a high sensitivity and specificity in diagnosing facet disease. We prospectively evaluated the use of bone scintigraphy with SPECT for the identification of patients with low back pain who would benefit from medial branch block.

Methods

SPECT was performed on 33 patients clinically suspected of facet joint disease. After SPECT, an ultrasound guided medial branch block was performed on all patients. On 28 SPECT-positive patients, medial branch block was performed based on the SPECT findings. On 5 negative patients, medial branch block was performed based on clinical findings. For one month, we evaluated the patients using the visual analogue scale (VAS) and Oswestry disability index. SigmaStat and paired t-tests were used to analyze patient data and compare results.

Results

Of the 33 patients, the ones who showed more than 50% reduction in VAS score were assigned 'responders'. SPECT positive patients showed a better response to medial branch blocks than negative patients, but no changes in the Oswestry disability index were seen.

Conclusions

SPECT is a sensitive tool for the identification of facet joint disease and predicting the response to medial branch block.