Therapeutic effect of epidural dexamethasone palmitate in a rat model of lumbar spinal stenosis.

BACKGROUND: Dexamethasone palmitate (DEP), a prodrug of dexamethasone (DEX), is a synthetic corticosteroid medication distinguished by the inclusion of a fatty acid component known as palmitate. This study introduces DEP as a novel therapeutic option for spinal epidural injection, aiming to provide safer and longer-lasting pain relief as an alternative to for patients with spinal stenosis. METHODS: 40 rats were randomly divided into four groups: those receiving epidural administration of normal saline (NS), and DEP in the lumbar spinal stenosis (LSS) model, and non-model rats receiving epidural NS administration. Paw withdrawal thresholds to mechanical stimulation and motor function (neurogenic intermittent claudication) were observed for up to 21 days. Hematology and blood chemistry analyses were performed 1 week after drug therapy. Tissue samples were collected for steroid pathology examination to evaluate adhesion degree, perineural area inflammation, and chromatolysis in the dorsal root ganglion (DRG), and adrenal gland. RESULTS: The DEX and DEP groups demonstrated significant recovery from mechanical allodynia and motor dysfunction after 2 weeks of drug therapy (p<0.001). However, by the third week, the effect of DEX started to diminish while the effect of DEP persisted. Furthermore, the DEP group exhibited reduced fibrosis and less chromatolysis than the NS group. No steroid overdose or toxin was observed in any group. CONCLUSION: The epidural administration of DEP demonstrated therapeutic efficacy in reducing allodynia and hyperalgesia resulting from chronic DRG compression, thus offering prolonged pain relief. These findings underscore the potential of DEP as a promising treatment alternative for pain associated with LSS, serving as a viable substitute for .

Infectious complications following regional anesthesia: a narrative review and contemporary estimates of risk.

INTRODUCTION: Infectious complications following regional anesthesia (RA) while rare, can be devastating. The objective of this review was to estimate the risk of infectious complications following central neuraxial blocks (CNB) such as epidural anesthesia (EA), spinal anesthesia (SA) and combined spinal epidural (CSE), and peripheral nerve blocks (PNB). MATERIALS AND METHODS: A literature search was conducted in PubMed, Embase and Cochrane databases to identify reference studies reporting infectious complications in the context of RA subtypes. Both prospective and retrospective studies providing incidence of infectious complications were included for review to provide pooled estimates (with 95% CI). Additionally, we explored incidences specifically associated with spinal anesthesia, incidences of central nervous system (CNS) infections and, the incidences of overall and CNS infections following CNB in obstetric population. RESULTS: The pooled estimate of overall infectious complications following all CNB was 9/100 000 (95% CI: 5, 13/100 000). CNS infections following all CNB was estimated to be 2/100 000 (95% CI: 1, 3/100 000) and even rarer following SA (1/100 000 (95% CI: 1, 2/100 000)). Obstetric population had a lower rate of overall (1/100 000 (95% CI: 1, 3/100 000)) and CNS infections (4 per million (95% CI: 0.3, 1/100 000)) following all CNB. For PNB catheters, the reported rate of infectious complications was 1.8% (95% CI: 1.2, 2.5/100). DISCUSSION: Our review suggests that the risk of overall infectious complications following neuraxial anesthesia is very rare and the rate of CNS infections is even rarer. The infectious complications following PNB catheters seems significantly higher compared with CNB. Standardizing nomenclature and better reporting methodologies are needed for the better estimation of the infectious complications.

Relationship of pain relief with catastrophizing following interventional pain procedures for low back pain.

INTRODUCTION: Catastrophizing is associated with worse pain outcomes after various procedures suggesting its utility in predicting response. However, the stability of pain catastrophizing as a static predictor has been challenged. We assess, among patients undergoing steroid injections for chronic low back pain (cLBP), whether catastrophizing changes with the clinical response to pain interventions. METHODS: This prospective study enrolled patients undergoing fluoroscopic-guided injections for cLBP. Patients filled out Brief Pain Inventory (BPI) and Pain Catastrophizing Scale (PCS) at baseline and 1-month follow-up. We assessed the change in PCS scores from pre-injection to post-injection and examined its predictors. We also examined the correlation of various domains of BPI, such as pain severity and effect on Relationships, Enjoyment, and Mood (REM), with PCS scores at baseline and follow-up. RESULTS: 128 patients were enrolled. Mean (SD) PCS and pain severity scores at baseline were 22.38 (±13.58) and 5.56 (±1.82), respectively. Follow-up PCS and pain severity scores were 19.76 (±15.25) and 4.42 (±2.38), respectively. The change in PCS pre-injection to post-injection was not significant (p=0.12). Multiple regression models revealed baseline PCS and REM domain of BPI as the most important predictors of change in PCS after injection. Pain severity, activity-related pain, age, sex, insurance status, depression, prior surgery, opioid use, or prior interventions did not predict change in PCS score. In correlation analysis, change in PCS was moderately correlated with change in pain (r=0.38), but weakly correlated with baseline pain in all pain domains. CONCLUSIONS: PCS showed non-significant improvement following steroid injections; the study was not powered for this outcome. Follow-up PCS scores were predicted by the REM domain of BPI, rather than pain severity. Larger studies are needed to evaluate a statistically significant and clinically meaningful change in catastrophizing scores following pain interventions.

Mepivacaine dosing for spinal anesthesia in pediatric orthopedic surgery: a retrospective chart review.

BACKGROUND: Mepivacaine is an intermediate-acting local anesthetic used for spinal anesthesia in adults. Currently, there are no published dosing guidelines for spinal mepivacaine in patients under age 18. AIMS: The purpose of this study is to describe the clinically used doses of mepivacaine by weight and age for orthopedic surgery in pediatrics. METHODS: We performed a retrospective chart review of patients aged 0-18 who received mepivacaine for spinal anesthesia from 2016 to 2022. We performed a secondary analysis for patients aged 0-18 who received spinal anesthesia with bupivacaine or chloroprocaine. RESULTS: The data extraction yielded 3627 single-shot mepivacaine spinals. Patient age ranged from 5 to 18 years. Median dosage in milligrams/kilograms (mg/kg) of mepivacaine was calculated for each age group. Our analysis revealed that dosage in mg/kg decreased by patient age and began to plateau at age 15. Bupivacaine was the most common single-shot spinal agent in patients under age 10. After age 10, mepivacaine was more common. Chloroprocaine began to be used in patients older than 8 years. CONCLUSIONS: We describe mepivacaine dosage as a function of age and weight in patients younger than 18 years. As age and weight increased, a lower dose of mepivacaine per kg was administered for spinal anesthesia.

Mechanism of chronic iatrogenic CSF leak following dural puncture-ventral dural leak: case report.

BACKGROUND: Postdural puncture headache has been traditionally viewed as benign, self-limited, and highly responsive to epidural blood patching (EBP) when needed. A growing body of data from patients experiencing unintended dural puncture (UDP) in the setting of attempted labor epidural placement suggests a minority of patients will have more severe and persistent symptoms. However, the mechanisms accounting for the failure of EBP following dural puncture remain obscure. An understanding of these potential mechanisms is critical to guide management decisions in the face of severe and persistent cerebrospinal fluid (CSF) leak. CASE PRESENTATION: We report the case of a peripartum patient who developed a severe and persistent CSF leak unresponsive to multiple EBPs following a UDP during epidural catheter placement for labor analgesia. Lumbar MRI revealed a ventral rather than dorsal epidural fluid collection suggesting that the needle had crossed the thecal sac and punctured the ventral dura, creating a puncture site not readily accessible to blood injected in the dorsal epidural space. The location of this persistent ventral dural defect was confirmed with digital subtraction myelography, permitting a transdural surgical exploration and repair of the ventral dura with resolution of the severe intracranial hypotension. CONCLUSIONS: A ventral rather than dorsal dural puncture is one mechanism that may contribute to both severe and persistent spinal CSF leak with resulting intracranial hypotension following a UDP.

Differences in the association between epidural analgesia and length of stay by surgery type: an observational study.

INTRODUCTION: Despite a decline in the use of thoracic epidural analgesia related in part to concerns for delayed discharge, it is unknown whether changes in length of stay (LOS) associated with epidural analgesia vary by surgery type. Therefore, we determined the degree to which the association between epidural analgesia (vs no epidural) and LOS differed by surgery type. METHODS: We conducted an observational study using data from 1747 patients who had either non-emergent open abdominal, thoracic, or vascular surgery at a single tertiary academic hospital. The primary outcome was hospital LOS and the incidence of a prolonged hospital LOS defined as 21 days or longer. Secondary endpoints included escalation of care, 30-day all-cause readmission, and reason for epidural not being placed. The association between epidural status and dichotomous endpoints was examined using logistic regression. RESULTS: Among the 1747 patients, 85.7% (1499) received epidural analgesia. 78% (1364) underwent abdominal, 11.5% (200) thoracic, and 10.5% (183) vascular surgeries. After adjustment for differences, receiving epidural analgesia (vs no epidural) was associated with a 45% reduction in the likelihood of a prolonged LOS (p<0.05). This relationship varied by surgery type: abdominal (OR 0.42, 95% CI 0.23 to 0.79, p<0.001), vascular (OR 1.66, 95% CI 0.17 to 16.1, p=0.14), and thoracic (OR 1.07, 95% CI 0.20 to 5.70, p=0.93). Among abdominal surgical patients, epidural analgesia was associated with a median decrease in LOS by 1.4 days and a 37% reduction in the likelihood of 30-day readmission (adjusted OR 0.63, 0.41 to 0.97, p<0.05). Among thoracic surgical patients, epidural analgesia was associated with a median increase in LOS by 3.2 days. CONCLUSIONS: The relationship between epidural analgesia and LOS appears to be different among different surgical populations.

Correlation between epidural space depth measured with ultrasound and MRI compared to clinical loss of resistance when performing lumbar epidural steroid injection.

BACKGROUND: This prospective study assessed the accuracy of MRI and ultrasound (US) measurements as a preprocedural assessment tool for predicting clinical loss of resistance depth (CLORD) during fluoroscopy-guided lumbar epidural steroid injections (ESIs). MATERIALS AND METHODS: Sixty patients enrolled received lumbar ESIs at an academic chronic pain clinic. The MRI measurement calculated the distance between the skin and the posterior epidural space, while US measurements included transverse and parasagittal oblique views of the interlaminar space. The epidural space measurements were compared with the CLORD during the performance of the prone epidural injections. The differences in measurements were analyzed using two one-sided tests for equivalency with a 0.5 equivalency margin. The intraclass correlation coefficients between CLORD and the imaging modalities were estimated using mixed effects models. RESULTS: MRI was equivalent to CLORD with a mean difference of -0.2 cm (95% CI -0.39 to -0.11). US transverse and US parasagittal oblique measurements were not equivalent to and underestimated CLORD with mean differences of -0.98 cm (90% CI -1.8 to -0.77) and -0.79 cm (90% CI -1.0 to -5.9), respectively. The intraclass correlation coefficients between MRI and CLORD were the highest at 0.85, compared with 0.65 and 0.73 for transverse and parasagittal oblique US views, respectively. CONCLUSIONS: MRI measurements are preferable over US for preprocedural assessment of patients receiving lumbar ESIs for predicting CLORD.

Literature review of spinal hematoma case reports: causes and outcomes in pediatric, obstetric, neuraxial and pain medicine cases.

BACKGROUND: The risk of spinal epidural hematoma (SEH) has been described in the literature but the impact in various patient populations has not been assessed in the same study. We identified the risk factors for SEH and calculated the OR for recovery in the pediatric, adult and obstetric (OB) patients based on the degree of neurological deficit before surgery. METHODS: Adult non-OB cases were categorized whether they were on anticoagulants or not; SEH was related to neuraxial or pain procedure; or whether there was adherence to the American Society of Regional Anesthesia (ASRA) guidelines. Eligible cases were identified through PubMed and Embase searches in the English literature from 1954 to July 2022. RESULTS: A total of 940 cases were evaluated. In the pediatric cases, SEH was typically spontaneous, related to coagulopathy or athletic trauma. OB cases were spontaneous or related to neuraxial injections. Among adults on anticoagulant(s), SEH was mostly spontaneous with no related etiology or related to neuraxial procedure. SEH occurred despite adherence to the ASRA guidelines. Among non-OB adults not on anticoagulants, SEH was due to trauma, neuraxial injections, surgery or other causes. Neurological recovery was related to the degree of neurological deficit before surgery. CONCLUSIONS: Our data show a preponderance of spontaneous SEH in all patient populations. SEH developed even though the ASRA guidelines were followed, especially in patients on multiple anticoagulants. Patients with less impairment prior to surgery had a higher likelihood of complete recovery, regardless of the interval between surgery and onset of symptoms.

Randomized control trial of a holographic needle guidance technique for thoracic epidural placement.

INTRODUCTION: The Microsoft HoloLens is a head-mounted mixed reality device, which allows for overlaying hologram-like computer-generated elements onto the real world. This technology can be combined with preprocedural ultrasound during thoracic epidural placement to create a visual of the ideal needle angulation and trajectory in the users' field of view. This could result in a technically easier and potentially safer alternative to traditional blind landmark techniques. METHODS: Patients were randomly assigned to one of two groups: (1) HoloLens-assisted thoracic epidural technique (intervention-group H) or (2) traditional thoracic epidural technique (control-group C). The primary outcome was needling time (defined as skin puncture to insertion of epidural catheter) during the procedure. The secondary outcomes were number of needle punctures, number of needle movements, number of bone contacts, and epidural failure. Procedural pain and recovery room pain levels were also evaluated. RESULTS: Eighty-three patients were included in this study. The primary outcome of procedure time was reduced in the HoloLens group compared with control (4.5 min vs 7.3 min, p=0.02, 95% CI), as was the number of needle movements required (7.2 vs 14.4, p=0.01), respectively. There was no difference in intraprocedure or postprocedure pain, bone contacts, or total number of needle punctures. Three patients in the control group experienced epidural failure versus one patient in the HoloLens group. CONCLUSIONS: This study shows that thoracic epidural placement may be facilitated by using a guidance hologram and may be more technically efficient. TRIAL REGISTRATION NUMBER: NCT04028284.

Neuraxial pathology and regional anesthesia: an education guide to decision-making.

In current clinical practice, spinal anesthesia and analgesia techniques-including epidural and subarachnoid procedures-are frequently executed without imaging like X-ray or epidurography. Unrecognized spinal pathology has resulted in serious morbidity in the context of performing neuraxial anesthesia. Typically, preoperative consultations incorporate a patient's medical history but lack a detailed spinal examination or consideration of recent MRI or CT scans. In contrast, within the domain of pain clinics, a multidisciplinary approach involving anesthesiologists and neuroradiologists is common. Such collaborative settings rely on exhaustive clinical history and scrutinization of recent imaging studies, which may influence the decision to proceed with invasive spinal interventions. There are no epidemiological data concerning rates of the different baseline pathologies that would potentially pose morbidity risks from neuraxial procedures, but the most common among these is canal stenosis, which significantly affects almost 20% of people over 60 years of age. This paper aims to elucidate these critical findings and advocate for incorporating meticulous preoperative assessments for individuals slated for spinal anesthesia or analgesia procedures, thereby attempting to mitigate potential risks.