Review of Sacroiliac Joint Injection Techniques.

PURPOSE OF REVIEW: The purpose of the review is to evaluate the current evidence on techniques for sacroiliac joint (SIJ) injections using landmark, ultrasound, fluoroscopy, and computed tomography (CT) guidance. METHODS: A literature search was performed to find all relevant retrospective, prospective, and randomized controlled (RCT) studies where SIJ injections were performed under ultrasound, fluoroscopy, and CT guidance. RECENT FINDINGS: A total of eight studies were identified with suitable data for inclusion. There were two RCTs, four prospective, and two retrospective studies included. Case reports or case series were excluded. A total of 420 patients were enrolled across all eight studies. CT guidance provided the most accurate needle placement in the SIJ injections followed by fluoroscopy, which was more accurate than ultrasound. Landmark-guided injections were not accurate. Accurate needle placement in SIJ confirms SIJ-mediated pain and injection of corticosteroids leads to improvement in pain and/or disability outcome measures regardless of guidance technique. Diagnostic CT-guided SIJ injections should be performed prior to consideration of SIJ fusion.

Review of Ilioinguinal Nerve Blocks for Ilioinguinal Neuralgia Post Hernia Surgery.

PURPOSE OF REVIEW: The purpose of this review is to evaluate the current evidence on ultrasound-guided ilioinguinal nerve blocks for ilioinguinal neuralgia post hernia surgery. METHODS: A literature search was performed to find all relevant case reports, case series, prospective or retrospective cohort studies, and randomized controlled trials (RCTs) where ultrasound-guided or landmark-based ilioinguinal nerve blocks were used for ilioinguinal neuralgia post-inguinal hernia surgery. RECENT FINDINGS: A total of six studies were identified with suitable data for inclusion. Three studies were retrospective, two studies were prospective, and one study was a randomized controlled trial. A total of 133 subjects were enrolled across these studies. Approximately 55-70% had a beneficial analgesic response to treatment. No major complications were reported in these studies. Ultrasound- and landmark-based ilioinguinal nerve blocks are safe and effective for pain relief post inguinal hernia surgery. Although there were two studies that did not show a statically significant difference in both techniques, the ultrasound-guided injection has the advantage of direct visualization of pathology, more accurate needle placement, and decreased risks of intravascular injections.

Complications Associated with Lumbar Transforaminal Epidural Steroid Injections.

PURPOSE OF REVIEW: Low back pain with radicular symptoms is a common cause of disability in the adult population in the USA. Lumbar transforaminal epidural steroid injection (TFESI) is one of the most frequently used intervention for lumbar radiculitis. The purpose of this review is to evaluate complications associated with lumbar TFESI. RECENT FINDINGS: Based on the literature review, the reported rate of minor complications was between 2.4 and 9.6%. The major complications including spinal abscess, spinal cord infarct, and epidural hematoma were documented as case reports. Some patients with spinal cord infarct had permanent neurologic deficits, while the other patients had recovery of neurological function after surgical or medical intervention. This review identifies both the minor and major complications related to lumbar transforaminal epidural steroid injections. According to this review, most complications are minor. Lumbar TFESI can be considered a safe treatment in the management of lumbar radicular pain. However, pain specialists should be aware of the potentially devastating major complications. Early recognition and treatment of complications are crucial for improving the outcome.

Role of venous blood gases in hypercapnic respiratory failure chronic obstructive pulmonary disease patients presenting to the emergency department.

BACKGROUND: Many patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have type 2 respiratory failure (T2RF). Often arterial blood gases are not performed and correlation with venous blood gases (VBG) is controversial. The venous pH and bicarbonate (HCO3 ) are useful, but VBG pCO2 (PvCO2 ) is considered too unpredictable. AIM: To examine the utility of VBG in this cohort of patients. METHODS: A prospective study of AECOPD patients with T2RF presenting to the emergency department was performed. Patients being considered for non-invasive ventilation and who required an arterial blood gas were invited to participate. A subsequent VBG was also taken, and Bland-Altman plots were used for analysis. RESULTS: Sixty-three patients were included in this study. The limits of agreement for pH and HCO3 were narrow. Wider limits of agreement with a systematic bias of 7.7 mmHg were noted with pCO2 . CONCLUSIONS: The utility of VBG pH and HCO3 was again demonstrated. VBG pCO2 in this cohort of patients may have a role in the assessment of patients with AECOPD. Further study is needed on the possible role of VBG in the management of such patients with T2RF particularly those using non-invasive ventilation.

Oral Appliance Treatment Response and Polysomnographic Phenotypes of Obstructive Sleep Apnea.

STUDY OBJECTIVES: Mandibular advancement splints (MAS) are an effective treatment for obstructive sleep apnea (OSA); however, therapeutic response is variable. Younger age, female gender, less obesity, and milder and supine-dependent OSA have variably been associated with treatment success in relatively small samples. Our objective was to utilize a large cohort of MAS treated patients (1) to compare efficacy across patients with different phenotypes of OSA and (2) to assess demographic, anthropometric, and polysomnography variables as treatment response predictors. METHODS: Retrospective analysis of MAS-treated patients participating in clinical trials in sleep centers in Sydney, Australia between years 2000-2013. All studies used equivalent customized two-piece MAS devices and treatment protocols. Treatment response was defined as (1) apnea-hypopnea index (AHI) < 5/h, (2) AHI < 10/h and ≥ 50% reduction, and (3) ≥ 50% AHI reduction. RESULTS: A total of 425 patients (109 female) were included (age 51.2 ± 10.9 years, BMI 29.2 ± 5.0 kg/m2). MAS reduced AHI by 50.3% ± 50.7% across the group. Supine-predominant OSA patients had lower treatment response rates than non-positional OSA (e.g., 36% vs. 59% for AHI < 10/h). REM-predominant OSA showed a lower response rate than either NREM or non-stage dependent OSA. In prediction modelling, age, baseline AHI, and anthropometric variables were predictive of MAS treatment outcome but not OSA phenotype. Gender was not associated with treatment outcome. CONCLUSION: Lower MAS treatment response rates were observed in supine and REM sleep. In a large sample, we confirm that demographic, anthropometric, and polysomnographic data only weakly inform about MAS efficacy, supporting the need for alternative objective prediction methods to reliably select patients for MAS treatment.

Comparative effects of two oral appliances on upper airway structure in obstructive sleep apnea.

STUDY OBJECTIVES: Oral appliances are increasingly being used for treatment of obstructive sleep apnea (OSA). Mandibular advancement splint (MAS) mechanically protrudes the mandible, while the tongue stabilizing device (TSD) protrudes and holds the tongue using suction. Although both appliances can significantly improve or ameliorate OSA, their comparative effects on upper airway structure have not been investigated. DESIGN: Cohort study. SETTING: Sleep Investigation Unit. PATIENTS: 39 patients undergoing oral appliance treatment for OSA. INTERVENTIONS: OSA patients underwent magnetic resonance imaging (MRI) of the upper airway during wakefulness at baseline and with MAS and TSD in randomized order. Treatment efficacy was determined by polysomnography in a subset of 18 patients. MEASUREMENTS AND RESULTS: Upper airway lumen and surrounding soft tissue structures were segmented using image analysis software. Upper airway dimensions and soft tissue centroid movements were determined. Both appliances altered upper airway geometry, associated with movement of the parapharyngeal fat pads away from the airway. TSD increased velopharyngeal lateral diameter to a greater extent (+0.35 ± 0.07 vs. +0.18 ± 0.05 cm; P<0.001) and also increased antero-posterior diameter with anterior displacement of the tongue (0.68 ± 0.04 cm; P<0.001) and soft palate (0.12 ± 0.03 cm; P<0.001). MAS resulted in significant anterior displacement of the tongue base muscles (0.35 ± 0.04 cm). TSD responders (AHI reduction ≥50%) increased velopharyngeal volume more than non-responders (+2.65 ± 0.9 vs. -0.44 ± 0.8 cm(3); P < 0.05). Airway structures did not differ between MAS responders and non-responders. CONCLUSIONS: These results indicate that the patterns and magnitude of changes in upper airway structure differ between appliances. Further studies are warranted to evaluate the clinical relevance of these changes, and whether they can be used to predict treatment outcome.

Comparison of mandibular advancement splint and tongue stabilizing device in obstructive sleep apnea: a randomized controlled trial.

STUDY OBJECTIVES: To compare the efficacy of a mandibular advancement splint (MAS) and a novel tongue stabilizing device (TSD) in the treatment of obstructive sleep apnea (OSA). DESIGN: A randomized crossover design was used. PATIENTS: Twenty-seven patients (20 male, 7 female), recruited from a tertiary hospital sleep clinic. MEASUREMENTS AND RESULTS: The apnea-hypopnea index (AHI) was reduced with MAS (11.68 +/- 8.94, P = 0.000) and TSD (13.15 +/- 10.77, P = 0.002) compared with baseline (26.96 +/- 17.17). The arousal index decreased for MAS (21.09 +/- 9.27, P = 0.004) and TSD (21.9 +/- 10.56, P = 0.001) compared with baseline (33.23 +/- 16.41). Sixty-eight percent of patients achieved a complete or partial response with MAS, compared with 45% with TSD. The Epworth Sleepiness Scale (ESS) score was decreased with MAS (P = < 0.001) and TSD (P = 0.002). Subjective improvements in snoring and quality of sleep were reported, with a better response for MAS than TSD. Compliance was poorer for TSD, and the side effect profiles of the 2 modalities were different. All patients were satisfied with MAS compared to TSD, and 91% of patients preferred the MAS. CONCLUSION: Objective testing showed the MAS and TSD had similar efficacy in terms of AHI reduction. Patients reported improvements with both devices; however, better compliance and a clear preference for MAS was apparent when both devices were offered. Longer term studies are needed to clarify the role of TSD.

Influence of nasal resistance on oral appliance treatment outcome in obstructive sleep apnea.

It has been recognized that nasal airway resistance (NAR) is elevated in patients with OSA. However, little is known regarding the influence of nasal resistance on mandibular advancement splint (MAS) treatment outcome in OSA patient. We hypothesized that nasal resistance differs between MAS responders and nonresponders and therefore may influence treatment outcome. Thirty-eight patients with known OSA underwent polysomnography while wearing a custom-made MAS. Treatment outcome was defined as follows: Responders (R) > or =50% reduction in AHI, and Nonresponders (NR) as <50% reduction in AHI. NAR was measured using posterior rhinomanometry in both sitting and supine positions, with and without MAS. The mean AHI in 26 responders was significantly reduced from 29.0 +/- 2.9/h to 6.7 +/- 1.2/h; P < 0.01). In 12 nonresponders there was no significant change in AHI (23.9 +/- 3.0/h vs 22.0 +/- 4.3/h; P=ns). Baseline NAR was significantly lower in responders in the sitting position compared to nonresponders (6.5 +/- 0.5 vs 9.4 +/- 1.0 cm H2O; P < 0.01). There was no significant change in NAR (from baseline) with MAS in either response group while in the sitting position, but in the supine position NAR increased significantly with MAS in the nonresponder group (11.8 +/- 1.5 vs. 13.8 +/- 1.6 cm H2O/L/s; P < 0.01). Logistic regression analysis revealed that NAR and BMI were the most important predictive factors for MAS treatment outcome. These data suggest that higher levels of NAR may negatively impact on treatment outcome with MAS.

Use of flow-volume curves to predict oral appliance treatment outcome in obstructive sleep apnea.

BACKGROUND: It has been recognized that mandibular advancement splint (MAS) treatment is effective in some, but not all, patients with obstructive sleep apnea (OSA). Hence there is a need for a simple and reliable clinical tool to assist in the differentiation of treatment responses. We hypothesized that abnormalities of flow-volume curves, together with other clinical variables, may have clinical utility in the prediction of MAS treatment outcome. METHODS: Fifty-four patients with known OSA underwent MAS treatment. Expiratory and inspiratory flow-volume curves were measured in the erect and supine positions to derive midinspiratory flow (MIF(50)) and the ratio of expiratory to inspiratory flow at 50% of vital capacity (MEF(50):MIF(50)). Multivariable logistic regression was performed to identify additional significant clinical variables in the prediction of treatment outcome. RESULTS: The mean (+/- SD) apnea-hypopnea index (AHI) in 35 responders was significantly reduced from 28.9 +/- 13.7 to 6.7 +/- 5.8/hour (p<0.001). In 19 nonresponders there was no significant change in AHI. MIF(50) was lower (6.04 +/- 1.80 vs. 6.88 +/- 1.08 L/second; p=0.035) and the MEF(50):MIF(50) ratio was higher (0.82 +/- 0.23 vs. 0.61 +/- 0.15; p=0.001) in responders than nonresponders. Logistic regression analysis revealed that the MEF(50):MIF(50) ratio was the most important predictive factor for MAS treatment outcome, but that body mass index, age, and baseline AHI were also contributory. CONCLUSIONS: These data suggest that flow-volume curves, in combination with other factors such as body mass index, age, and baseline AHI, may have a useful clinical role in the prediction of treatment outcome with MAS.

Oropharyngeal collapse predicts treatment response with oral appliance therapy in obstructive sleep apnea.

STUDY OBJECTIVES: To examine whether primary oropharyngeal collapse of the upper airway during sleep predicts treatment success with oral appliance therapy in patients with obstructive sleep apnea. DESIGN: Prospective physiologic study. SETTING: Multidisciplinary sleep disorders clinic in a university teaching hospital. PATIENTS: Twelve treatment-naïve adult patients with obstructive sleep apnea (apnea-hypopnea index > or = 10/h and at least 2 of the following symptoms: snoring, fragmented sleep, witnessed apneas, or daytime sleepiness). INTERVENTION: Custom-made mandibular advancement splint (MAS). MEASUREMENTS AND RESULTS: A baseline diagnostic polysomnogram confirmed AHI > or = 10 per hour. During the following acclimatization period, a custom-made adjustable MAS was incrementally advanced until maximum comfortable mandibular protrusion was reached. A second polysomnogram with MAS in situ determined efficacy. Following a 1-week washout period, a final sleep study was performed using multisensor catheters (with and without MAS, in random order during the same night) to determine upper-airway closing pressures and the site or sites of upper-airway collapse. MAS resulted in significant improvements, mean +/- SEM, in AHI (22.0 +/- 2.6 vs 9.2 +/- 1.9/h, p < .01) and upper-airway closing pressures during stage 2 non-rapid eye movement sleep (-1.1 +/- 0.3 vs -2.8 +/- 0.5 cm H2O, p < .01). All 4 patients with primary oropharyngeal collapse achieved an AHI < 5 per hour. Only 1 of the 8 patients with primary velopharyngeal collapse achieved an AHI < 5 per hour. Oropharyngeal collapse, compared with velopharyngeal collapse, predicted treatment success with MAS (p < .02). CONCLUSIONS: These preliminary data suggest that primary oropharyngeal collapse of the upper airway during sleep is an important predictor of treatment outcome with MAS therapy.

Effect of oral appliance therapy on upper airway collapsibility in obstructive sleep apnea.

Oral appliance therapy is emerging as an alternative to continuous positive airway pressure for the treatment of obstructive sleep apnea (OSA). However, its precise mechanisms of action are yet to be defined. We examined the effect of a mandibular advancement splint (MAS) on upper airway collapsibility during sleep in OSA. Ten patients with proven OSA had a custom-made MAS incrementally adjusted during an acclimatization period until the maximum comfortable limit of mandibular advancement was reached. Polysomnography with the splint was then performed. After a 1-week washout period, upper airway closing pressures during sleep (with and without MAS) were determined. Significant improvements with MAS therapy were seen in the apnea/hypopnea index (25.0 +/- 3.1 vs. 13.2 +/- 4.5/hour, p < 0.03) and upper airway closing pressure in Stage 2 sleep (-1.6 +/- 0.4 vs. -3.9 +/- 0.6 cm H2O, p < 0.01) and in slow wave sleep (-2.5 +/- 0.7 vs. -4.7 +/- 0.6 cm H2O, p < 0.02) compared with no therapy. These preliminary data indicate that MAS therapy is associated with improved upper airway collapsibility during sleep. The mediators of this effect remain to be determined.