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Item does not contain fulltext INTRODUCTION: Dorsal root ganglion stimulation (DRG-S), has demonstrated superiority in the treatment of complex regional pain syndrome and causalgia. Lead migration and fracture impact DRG-S therapeutic stability. Lead anchoring reduces DRG-S lead migration without increasing lead fracture. Lead fracture may be related to lead entrapment in the superficial fascial plane. A novel medialized approach for lead placement and anchoring is presented to address these issues. METHODS: We suggest an alternative technique for implanting percutaneous DRG-S leads at the T10-L5 levels. RESULTS: A novel medialized ipsilateral technique for lead placement and anchoring for single, bilateral, and adjacent segment placement is presented. The Tuohy needle puncture site is medial to the pedicle and adjacent to the spinous process, two vertebral levels caudad to the target foramen. Trajectory is maintained in the sagittal plane, to access the caudad interlaminar space near the midline. This technique allows for ipsilateral or contralateral lead placement. After epidural access, the introducer sheath is rotated toward the targeted foramen and advanced. The guidewire followed by the lead is passed, and once lead position is confirmed, tension "S" loops are created, followed by anchoring to the deep fascia. CONCLUSION: We describe a new paramedian technique for DRG-S lead placement. We propose it will decrease DRG-S complication rates through anchoring to reduce migration and by avoiding the fascial planes thought to be responsible for fracture. Long-term outcomes applying our proposed techniques are required for determining the true impact, however, early anecdotal results suggest that these new techniques are favorable.

INTRODUCTION Transforaminal epidural steroid injection (TFESI) is one of the nonoperative interventions for lower back pain. In this study, we presented an alternative approach for TFESI, far lateral lateral recess TFESI (FLLR TFESI), which is targeted on lateral recess and anterior epidural space in patients with degenerative lumbar spondylosis-related radiculopathy. TECHNIQUE Under fluoroscopy, needle entry site and pathway are drawn according to the spinal anatomy. The needle is advanced toward the lateral recess and the needle tip is placed medially to the medial border of the pedicle under anteroposterior view and posteriorly to the posterior border of the upper endplate under lateral view. After checking optimal contrast spread, steroids and local anesthetics are injected. CASE ILLUSTRATION An 86-year-old woman who suffered from lower back pain with radiculopathy received interventional treatment. Comparing the "traditional" supraneural approach with the FLLR approach, the difference in contrast enhancement to lateral recess is clearly shown. DISCUSSION Compared to the pre-existing approaches, the FLLR approach may provide better ventral epidural and lateral recess enhancement. Furthermore, with the advanced needle tip, the injectate may enhance not only the at-level nerve root but also the nerve root of adjacent level during their existence in a single injection. With blunt needle usage, no nerve root injury or dura puncture was noted so far. CONCLUSION FLLR TFESI is a modified fluoroscopic technique targeted on lateral recess and anterior epidural space. However, subsequent trials are needed to confirm its efficacy in pain reduction and the rate of complications.

BACKGROUND Infants and children require a larger dose of a local anaesthetic (LA) to establish epidural analgesia than adults, but the reason for this remains unclear. We hypothesised that prominent ventro-dorsal expansion of the epidural space limits cranio-caudal spread of LA in infants. Accordingly, we studied the dimensions of the epidural space with real-time ultrasound (US) before and after epidural injection. METHODS Ninety-six infants and children aged 0-12 years who underwent abdominal surgery under combined epidural and general anaesthesia were examined in this prospective observational study. Using a micro-convex probe, US recordings of the posterior epidural space were performed while a LA (0.5 ml kg-1 ) was infused at 0.54 ml s-1 . The width in the ventro-dorsal dimension (VDD) of the posterior epidural space before and after injection was recorded; the change in VDD was defined as "ballooning". Correlations between "ballooning" and patient age, body mass index, and volume and rate of LA administration were analysed. RESULTS "Ballooning" correlated positively but weakly with age (R2 = 0.25; p

BACKGROUND Epidural tunneling could help with prolonged catheterization and be effective in preventing infection and dislodgement. However, epidural tunneling techniques carry a risk of catheter shear or needlestick injuries. AIMS This study aimed to examine the safety of our epidural tunneling technique in terms of catheter shear. METHODS This study was designed as a double-blinded, single-crossover, in vitro study. Each of the operators performed two techniques to create a subcutaneous tunnel. We compared outcomes between the control tunneling technique (group C) and our improved technique (group I). Microscopic findings of catheter shear were assessed as the primary outcome. Secondary outcomes included the tension and displacement required to break the epidural catheter and the frequency of catheter breakage due to catheter shear. Data were analyzed using the Fisher's exact test and Mann-Whitney U test. A p-value of

Background Thoracic epidural anesthesia for open infantile hypertrophic pyloric stenosis surgery is a controversial issue in the presence of little comparative data. Aims To compare this approach to general anesthesia for desaturation events (≤90% oxygen saturation) and absolute values of minimal oxygen saturation, minimal heart frequency, operating‐room occupancy time, and durations of surgery in a retrospective study design. Methods Data were retrieved for patients with infantile hypertrophic pyloric stenosis managed by thoracic epidurals under sedation or general anesthesia with rapid sequence induction between 01/2007 and 12/2017. Oxygen saturation and heart rate were analyzed over eight 5‐minutes intervals relative to the start of anesthesia / sedation (four‐time intervals) and before discharge of the patient from the operating room (four‐time intervals). Fisher's exact tests and mixed model two‐way analysis of variance for repeated measures were employed for intergroup comparisons. Results The epidural and general anesthesia groups included 69 and 32 evaluable infants, respectively. Patients managed under epidural anesthesia had cumulatively higher minimimal mean (SD) oxygen saturation values (98.2 [2.6] % versus 96.6 [5.2] %, p < 0.001) and lower minimal mean (SD) heart rate values (127.9 [15.0] beats per minute versus 140.7 [17.2] beats per minute, p < 0.001) over time. Similarly, the frequency of desaturation events (defined as ≤90% oxygen saturation) was significantly lower for these patients during the period of 5 minutes after induction of sedation or general anesthesia (odds ratio 7.4 [2.1–25.9]; p = 0.001) and during the subsequent period of five minutes (odds ratio 6.2 [1.1–33.9]; p = 0.031). One case of prolonged respiratory weaning was observed in the general anesthesia group. The mean (SD) operating‐room occupancy was 61.9 (16.6) minutes for the epidural anesthesia group versus 73.3 (22.2) minutes for the general anesthesia group (p = 0.005) as a result of shorter emergence from sedation. Conclusions In our series, maintaining spontaneous breathing with minimal airway manipulation in patients undergoing open repair of hypertrophic pyloric stenosis under single‐shot epidural anesthesia resulted in fewer desaturation events ≤90% than general anesthesia. In addition, this approach seems to result in shorter turnover times in the operating room.

Extramedullary hematopoiesis is a normal compensatory reaction that can affect the epidural space, leading to spinal cord compression syndrome. MRI is the imaging method of choice for diagnosis and monitoring. Treatment is still controversial.

The peridural membrane (PDM) is a well-defined structure between dura mater and the wall of the spinal canal. The spine may be viewed as a multi-segmented joint, with the epidural cavity and neural foramina as joint spaces and PDM as synovial lining. The objective of this investigation was to determine if PDM has histological characteristics of synovium. Samples of the PDM of the thoraco-lumbar spine were taken from 23 human cadavers and analyzed with conventional light microscopy and confocal microscopy. Results were compared to reports on similar analyses of synovium in the literature. Histological distribution of areolar, fibrous, and adipose connective tissue in PDM was similar to synovium. The PDM has an intima and sub-intima. No basement membrane was identified. CD68, a marker for macrophage-like-synoviocytes, and CD55, a marker for fibroblast-like synoviocytes, were seen in the lining and sub-lining of the PDM. Multifunctional hyaluronan receptor CD44 and hyaluronic acid synthetase 2 marker HAS2 were abundantly present throughout the membrane. Marked presence of CD44, CD55, and HAS2 in the well-developed tunica muscularis of blood vessels and in the body of the PDM suggests a role in the maintenance and lubrication of the epidural cavity and neural foramina. Presence of CD68, CD55, and CD44 suggests a scavenging function and a role in the inflammatory response to noxious stimuli. Thus, the human PDM has histological and immunohistochemical characteristics of synovium. This suggests that the PDM may be important for the homeostasis of the flexible spine and the neural structures it contains.

A peridural membranous layer exists between the bony wall of the spinal canal and the dura mater, but reports on the anatomy of this structure have been inconsistent. The objective of this study is to give a precise description of the peridural membrane (PDM) and to define it unambiguously as a distinct and unique anatomical entity. Thirty-four cadaveric sections of human thoraco-lumbar spines were dissected. On gross examination, the PDM appears as a smooth hollow tube that covers the bony wall of the spinal canal. An evagination of this tube into the neural foramen contains the exiting spinal nerve. The entire epidural venous plexus, including its extension into the neural foramina, is contained in the body of the PDM. Histological examination of the PDM shows a variable distribution of veins arteries, lymphatics, and nerves embedded in a continuous sheath of fibrous, areolar, and adipose tissue. The posterior longitudinal ligament may be considered a dense condensation of fibrous tissue within the membrane. Thus, the PDM is a unique, continuous, and complete anatomical structure. In the spinal canal, the PDM is adjacent to the periosteum. In the neural foramen, suprapedicular PDM and pedicular periosteum separate anatomically to form a suprapedicular compartment, bounded anteriorly by the intervertebral disc and posteriorly by the facet joint. Trauma or degeneration of the disc or facet joint may lead to inflammation and pain sensitization of PDM. This protective mechanism may be of considerable importance for the functioning of the spine under conditions of strain.

We present the case of a 33‐year‐old parturient who required caesarean delivery at 31 weeks' gestation. She had a history of degenerative disease of the lumbar spine secondary to tuberculosis, acquired as a child in India. Her complex medical history also included ischaemic heart disease and obstructive sleep apnoea, and due to this general anaesthesia was considered to be of high risk. However, regional anaesthesia also posed significant challenges because magnetic resonance imaging of the spine showed a partial collapse with subsequent fusion of second and third lumbar vertebral bodies with thoracolumbar kyphosis. Neuraxial anaesthesia was performed with ultrasound guidance for determining levels and depth of epidural space. An epidural was inserted at the T12–L1 interspace and a spinal anaesthetic block was placed at L4–L5. Delivery and recovery were uneventful. This case highlights the safe and effective use of neuraxial anaesthesia in an asymptomatic patient with treated spinal tuberculosis as well as the usefulness of high‐quality imaging of the spine in the decision to perform neuraxial anaesthesia.

The spinal epidural and posterior ligamentous complex spaces are important anatomic regions which are the target of various radiologic procedures in the cervical, thoracic and lumbar spine for the purpose of analgesia and anaesthesia. Given the frequency with which procedures are performed in and around the epidural space, a sound understanding of the associated anatomy is paramount to ensure the safety and efficacy of procedural intervention.

Background Caudal epidural anesthesia is a frequently performed regional anesthesia block in infants and young children. Traditional landmark-based blind needle insertion remains the norm with no immediate, objective method to determine the presence of local anesthetic in the epidural space. Increasingly, ultrasound-imaging is used in pediatric regional anesthesia with demonstrated improvements in block efficacy and efficiency. The value of ultrasound-imaging in confirming success rate of traditional caudal placement is not well defined. Aim To assess the success rate of conventional landmark-based caudal technique using ultrasound-imaging. Methods Prospective observational study of 30 children ages 1 month to 7 years undergoing surgical procedures with consent for caudal blockade. Provider success rate of caudal blockade placed by landmark technique was measured using ultrasound-imaging of needle tip and local anesthetic flow in the epidural space. Results Ultrasound-imaging demonstrated 80% success to correct positioning of the needle tip and local anesthetic in the epidural space. Failure was associated with decreasing experience and presence of anatomic variances. All improperly positioned needles were subsequently successfully positioned using real-time ultrasound-imaging. Mean time for confirmatory ultrasound-imaging (SD; range) was 1 minute (0.3; 1-3). Conclusion The use of ultrasound-imaging can be used to identify proper needle placement in the sacral epidural canal and facilitate subsequent corrected placement.

Background The erector spinae plane block (ESP) is a novel approach for blockade of the spinal nerves in infants, children, and adults. Until recently, the gold standard for truncal procedures includes the paravertebral and epidural blocks. However, the exact mechanism by which this blockade is achieved is subject to debate. Methods 2.3 mL (1 mL/kg) of iodinated contrast dye was injected bilaterally into the erector spinae fascial plane of a fresh unembalmed preterm neonatal cadaver (weighing 2.3 kg), to replicate the erector spinae plane block and to track the cranio-caudal spread of the contrast dye using computed tomography. The "block" was performed at vertebral level T8 on the right-hand side and at vertebral level T10 on the left-hand side. Results Contrast dye was spread over three dermatomal levels from T6 to T9 on the right-hand side, while on the left-hand side, the spread was seen over four dermatomal levels from T9 to T11/12. Contrast dye also spread over the costotransverse ligament, into the paravertebral space and further lateral from the lateral border of the erector spinae muscle into the intercostal space. However, no spread was seen in the epidural space. Conclusion The erector spinae plane block is a versatile technique that can be part of the multimodal postoperative analgesic strategy for truncal surgery. In this study, contrast material dye was tracked over four vertebral levels in the paravertebral space (suggesting an approximate volume of 0.5-0.6 mL per dermatome).

Spinal cord epidural stimulation (SCES) exhibits a rehabilitation potential of restoring locomotion in individuals with spinal cord injury (SCI). However, this is linked to an intensive rehabilitation locomotion approach, which is impractical to apply among a large clinical SCI population. We, hereby, propose a rehabilitation approach of using SCES to enhance motor control during exoskeletal‐assisted walking (EAW). After 24 sessions (12 weeks) of EAW swing assistance decreased from 100% to 35% in a person with C7 complete SCI. This was accompanied by 573 unassisted steps (50% of the total number of steps). Electromyographic pattern improved during EAW, reflecting the subject’s ability to rhythmically activate paralyzed muscles. Rate perceived exertion increased during EAW with SCES compared to stepping without SCES. These preliminary findings suggest that using SCES with EAW may be a feasible rehabilitation approach for persons with SCI.

Extramedullary hematopoiesis (EMH) can rarely involve the epidural space, leading to spinal cord compression syndrome. No treatment guidelines have been established yet., Magnetic resonance imaging showing spectacular improvement of epidural and sacral extramedullary hematopoiesis after radiotherapy in a 23‐year‐old Tunisian man with thalassemia major.

Variations in the venous drainage of the central nervous system can have imaging and clinical findings that mimic pathology, presenting a challenge for neuroimagers and clinicians. Patients with these variants may undergo unnecessary testing, and patients with pathology may receive delayed diagnoses because of overlap with benign findings. Consequently, the accurate identification of venous variations on cross-sectional imaging and angiography and their potential causes are critical for differentiating benign imaging variants from potential pathologic processes requiring further evaluation. For example, in the epidural space, benign dilation of the epidural venous plexus may be mistaken for evidence of a fistula, abscess, or metastasis. Hypoplasia of a dural venous sinus or an arachnoid granulation may mimic venous sinus thrombosis. The superior ophthalmic vein may demonstrate benign dilation in intubated patients, mimicking thrombosis, increased intracranial pressure, orbital varix, inflammatory pseudotumor, or other conditions. Furthermore, certain venous variations, such as the occipital sinus or emissary veins, may complicate surgery or herald pathology and should be reported. In addition, some supposedly benign variations, such as the developmental venous anomaly, can be complicated by pathology. The objective of this review article is to provide a descriptive and pictorial review of common anatomic and physiologic variations in the venous drainage system of the brain, spine, and orbits that can mimic pathology. Neuroimaging findings of related pathologies and differences in clinical presentations will also be discussed to assist in the approach to differential diagnosis.

Background Cervical epidural steroid injection (CESI) with local anesthetics is commonly used to treat neck pain and radicular pain of the upper extremity. Local anesthetic systemic toxicity (LAST) occurs shortly after injection as a complication; however, delayed onset is a very rare event, especially in central nervous system (CNS) block. Case report We present a case in which delayed onset of LAST occurred in a patient who received CESI for cervical and arm radiating pain due to a cervical disc protrusion. We performed the interlaminar approach for CESI using fluoroscopic guidance. After confirming the location of the epidural space using the loss of resistance technique and spreading of contrast agent (Telebrix® 30), a mixture of 0.25% levobupivacaine 12.5 mg (5 mL in volume), hyaluronidase 1,500 IU (1 mL), dexamethasone 5 mg (1 mL), and normal saline 3 mL was administrated. After 50 minutes of injection, the patient showed CNS toxicity (unconsciousness, seizure) with normal blood pressure and tachycardia; therefore, she was immediately sedated with intravenous midazolam (3 mg), and 15 L/min of oxygen was administered. The patient fully recovered after 30 minutes of sedation without any sequelae. Conclusion Delayed onset of LAST is a rare complication of a common procedure in CESI, so it is important to be aware of this complication and the presentation of toxicity.

Epidural adhesion between the spinal dura and the surrounding fibrous tissue often occurs post-laminectomy, resulting in clinical symptoms such as nerve compression and severe pain. In this study, we report a drug-loaded double-layered electrospun nanofiber membrane to prevent the occurrence of epidural adhesion. The nanofibers in both layers are made of a mixture of polycaprolactone (PCL) and chitosan (CS) but at different weight ratios. The bottom layer contacting to the spinal dura is loaded with meloxicam (MX) to prevent inflammation. The top layer that contacts to the fibrous tissue is doped with mitomycin-C (MMC) to inhibit the synthesis of DNA and collagen. The two types of drugs are released from the double-layered membrane within about 12 days. Meanwhile, the membrane can inhibit fibroblasts proliferation in vitro while show no cytotoxicity. In a rabbit laminectomy model, the double-layered membrane can effectively prevent the epidural adhesion formation based on the adhesion scores, histological and biochemical evaluations. The combination release of MX and MMC can signally reduce the inflammation reaction and collagen I/III expression relative to the case with the membranes loaded with only either one type of the drugs. This approach offers new progresses in constructing dual drug delivery system and provides innovative barrier strategy in inhibiting epidural adhesion post-laminectomy.

INTRODUCTION The morphological characteristics of skeletal muscles innervated caudal to a spinal cord injury (SCI) undergo dramatic phenotypic and microvascular changes. METHOD Female Sprague-Dawley rats received a severe contusion at thoracic level 9/10 and were randomly assigned to locomotor training, epidural stimulation, or a combination of the treatment groups (CB). Fiber type composition and capillary distribution were assessed in phenotypically distinct compartments of the tibialis anterior. RESULTS Spinal cord injury induced a shift in type II fiber phenotype from oxidative to glycolytic (P

To electrophysiologically determine the predominant neural structures activated with cervical epidural stimulation (ES), well-established electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were delivered at rest, during motor activity and under anaesthesia in adult rats. Cervical ES resulted in spinal evoked motor responses with three different waveforms - early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. In contrast, MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. ERs are consequential to the direct activation of motor efferents; MRs are secondary to type-I sensory afferent activation and LRs result from the engagement of wider spinal interneuronal circuitry with potential influence from supraspinal pathways. Evidence from this work is fundamental in enhancing our understanding of cervical ES, and critical in refining the design of neuromodulation-based rehabilitative strategies and in the construction of neuroprosthetics.Epidural stimulation (ES) of the lumbar spinal cord has demonstrated significant improvements in various physiological functions after a traumatic spinal cord injury in humans. Electrophysiological evidence from rodent, human and computational studies collectively suggest that the functional recovery following lumbar ES is mediated via direct activation of sensory afferent fibres. However, the mechanisms underlying cervical ES have not been comprehensively studied, which greatly limits our understanding of its effectiveness in restoring upper limb function. In this work, we determined the predominant neural structures that are activated with cervical ES using in vivo cervical spinal evoked motor responses (SEMRs). Standard electrophysiological protocols (single-pulse, paired-pulse and multiple frequency stimulation) were implemented in 11 awake and anaesthetized rats in four experimental stages. Three distinct types of cervical SEMRs were identified based on latency of their appearance: early response (ER), middle response (MR) and late response (LR). ERs remained unmodulated by repeated stimulation protocols. MRs and LRs were modulated by repeated stimulation protocols and volitional motor activity. Except for LRs being completely abolished under urethane, ketamine or urethane anaesthesia did not affect the appearance of cervical SEMRs. Our data, backed by literature, suggest that ERs are secondary to the direct activation of motor efferents, MRs are elicited by activation of type-I sensory afferents and LRs result from the engagement of interneuronal circuitry with potential influence from supraspinal pathways. The gathered information paves the way to designing motor rehabilitation strategies that can utilize cervical ES to recover upper limb function following neurological deficits.

Lumbar epidural varices are a rare cause of radicular pain mimicking lumbar disc herniation or other cyst-like masses including sequestrated disc herniation, facet joint synovial cyst, or perineural cyst. We report a case of a 36-year-old woman presenting with lumbar radicular pain caused by a lumbar epidural varix. Lumbar magnetic resonance imaging (MRI) revealed a cystic lesion in the ventral epidural space posterior to the right L4 body. Surgery was conducted and histopathology confirmed the diagnosis of an epidural varix. Lumbar epidural varices and other lumbar cystic lesions can commonly cause radicular pain. Physicians will benefit from increased awareness of epidural varices as a cause of lumbosacral radicular pain and the associated radiologic findings supporting differential diagnosis. In particular, careful interpretation of MRI scans may help ensure proper diagnosis of an epidural varix versus other cystic lesions. LEVEL OF EVIDENCE: V.

To date, no case studies specifically reporting an electrode dislodging from its lead wire have been reported. Here we describe a case involving an electrode shearing from the spinal cord stimulator lead, and lodging into the ligamentum flavum during implantation. In this case, an experienced board certified interventional pain management specialist was performing the implantation procedure of a magnetic resonance imaging (MRI) compatible spinal cord stimulator with MR conditional leads. After successful placement of the first lead, the epidural space was accessed via a T11/12 interlaminar approach using loss of resistance technique. When the lead would not advance past the tip of the needle, it was removed in order to reposition the needle slightly. Upon removal of the lead, it was discovered that the first electrode was no longer attached to the wire. Subsequent fluoroscopic imaging revealed that the electrode had lodged within the ligamentum flavum. Upon discussion with the medical director of the device company, it was agreed upon that the electrode should be left in place. The decision was made to proceed with only one lead in place and the remainder of the procedure was completed uneventfully. The patient followed up two weeks later in clinic, and no adverse effect related to the dislodged electrode was reported. The indications and common complications associated with spinal cord stimulation are discussed, followed by factors to consider to help guide decision making in the event of a retained foreign body during a procedure.

Options to treat early-onset scoliosis include guided-growth systems with sliding action between rods and pedicle screws. The wear was previously measured in an in vitro test, and in this in vivo rabbit model, we evaluated the local and systemic biological response to the stainless steel debris. Compared to the previous study, a relatively higher volume of representative wear particles with a median particle size of 0.84 μm were generated. Bolus dosages were injected into the epidural space at L4-L5 for a minimum of 36 rabbits across three treatment groups (negative control, 1.5 mg, and 4.0 mg) and two timepoints (12 and 24 weeks). Gross pathology evaluated distant organs and the injection site with a dorsal laminectomy to examine the epidural space and dosing site. Peri-implanted particle tissues were stained for immunohistochemical and quantitatively analyzed for IL-6 and TNF-α cytokines. Based on ISO 10993-6:2007 scoring, particles in the high-dose group were primarily non-irritant (12 weeks) with one slightly irritant. At 24 weeks, inflammatory cell infiltration was non-existent to minimal with all groups considered non-irritant at the injection site. Material characterization confirmed that particles detected in distant organs were stainless steel or contaminants. At 12 weeks, stainless steel groups demonstrated statistically increased amounts of cytokine levels compared to control but there was a statistical decrease for both at 24 weeks. These findings indicate that stainless steel wear debris, comparable to the expected usage from a simulated growth guidance system, had no discernible untoward biological effects locally and systemically in an animal model. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1980-1990, 2018.

Objectives Labor epidural analgesia failure may relate to nonmidline placement of epidural catheters. We hypothesized that greater deviations of the epidural catheter insertion point from the ultrasound (US)-determined midline would be associated with less effective labor analgesia. Methods A prospective ethically approved cohort study was conducted. Fifty-two healthy average-sized women receiving labor epidural analgesia, inserted by the landmark technique, were approached after delivery. Immediately after removing the epidural catheter, we determined the epidural space midline using US and compared it to the epidural catheter insertion point and to the patient-identified midline (assessed by a pinprick in 1-mm increments). Correlations between the US midline-to-catheter insertion point distance and additional epidural local anesthetic requirements (primary outcome), pain verbal numeric rating scale scores (0-10) 1 hour after epidural insertion, and maternal satisfaction with analgesia were determined. The differences in distances were assessed by a Bland-Altman analysis. Results There were no significant correlations between the US midline-to-epidural catheter insertion point distance and additional epidural local anesthetic requirements (R2 = 0.138; P = .33), pain verbal numeric rating scale scores 1 hour after the epidural (R2 = 0.121; P = .40) or maternal satisfaction (R2 = 0.085; P = .57). The Bland-Altman analysis revealed that the mean ± SD US midline-to-epidural catheter insertion point distance and patient-identified midline distances were 0.38 ± 0.31 and 0.35 ± 0.46 cm, respectively. Conclusions In our laboring population, the hypothesis that nonmidline epidural insertion is associated with less-effective labor analgesia was not confirmed in this study cohort. We found minimal differences in distances between the US midline to epidural catheter insertion point and US midline to patient-identified midline.

Key Clinical Message This is the first reported case in the veterinary literature of a knot in an epidural catheter. The report reviews this very rare complication and describes options for investigation and retrieval of catheters entrapped in the epidural space of any species.

The detection of epidural space is usually performed by the technique of loss of resistance (LOR) without technological support, although there are few commercial options. We sought to design and develop a new noninvasive system able to detect the LOR without any changes to the conventional procedure. It allows detecting the LOR by a custom made algorithm. The system provides a visual and acoustic feedback when the LOR is detected. We optimized the detection algorithm and investigated the performance of the system during experiments on a custom simulator. During the experiments performed by 10 anesthetists and 10 trainees, the pressure exerted on the syringe plunger was monitored using the custom-made system. Each participant performed four experiments using the system on the simulator. The performance of the system in LOR detection was evaluated comparing the feedback activation and the breaches of the last layer of the simulator. Moreover, each participant filled out a questionnaire to assess how the procedure with the simulator mimics the clinical scenario. A higher questionnaire score corresponds to a more realistic condition (0 = not real, 5 = extremely real). Results showed that the LOR was detected in 74 of the 80 trials (92.5% of the cases); the anesthetists obtained better results than trainees: 97.5 versus 87.5%. The questionnaires showed that all the participants found the trial realistic (score ≥3); anesthetists found it more realistic than trainees (4.2 ± 0.78 vs. 3.8 ± 0.78, mean ± SD). In summary, the proposed system successfully detected the LOR in the large part of the trials. The participants found the trials realistic. A higher success rate was observed in the anesthetists group.

SummaryBackground Caudo-lumbar and caudo-thoracic epidural anesthesia is an established technique that carries a low risk of dural puncture or spinal cord trauma in infants. Traditionally catheter advancement is based on external measurements. However, malpositioning of catheters are known to occur. We hypothesized that caudal-epidural catheters inserted under real-time ultrasound guidance may be more accurate than the accuracy of the measurements traditionally used for their placement. Methods We studied 25 patients, aged 2 days to 5 months, posted for abdominal or thoracic surgery, receiving general anesthesia followed by caudo-epidural continuous block. External measurement defined as the distance from the caudal space and the surgically congruent vertebral level was measured in centimeters with the back gently flexed. Subsequently, a caudo-epidural block was performed in the same position. The epidural catheter insertion was followed under real-time ultrasound guidance till the predetermined vertebral level was reached. The actual length placed under real-time ultrasound scan was defined as the actual length. The high-frequency probe was placed longitudinal and paramedian to the spine. The vertebral level was determined by identifying the lumbosacral junction in longitudinal saggital view and counting the vertebrae up from L5. The catheter length at the skin was compared with the length recorded by external measurement. Results The actual length placed under real-time ultrasound scan were consistently longer than the external distance between the caudal space and selected vertebral level. The mean values of ultrasound were higher than the mean values of external measurement with a difference of 4.28 cm. Accuracy was not affected by age or affected by the selected vertebral level in the age group we studied. Conclusion We conclude that catheters placed under ultrasound guidance are more accurate than the traditional method developed before the advent of ultrasound in young infants.

The aims of this study were to develop a population pharmacokinetic model of sufentanil coadministered with 0.2% ropivacaine as an epidural infusion in infants and describe the sufentanil absorption profile from epidural space. Data from 2 previously published studies were merged for analysis—20 infants aged 3–36 months receiving sufentanil as an epidural infusion and 41 children 0–17 years old receiving sufentanil as a long-term intravenous infusion. A population nonlinear mixed-effects model was built in NONMEM. Sufentanil pharmacokinetics were described by a 2-compartment model with first-order absorption. The effect of body size on all volume and clearance parameters was included in the model according to allometric scaling with theoretical exponents. The maturation process of metabolic clearance was described by the Hill model. During the model-building process the population was divided into 2 fractions with different typical values of metabolic clearance (CL1 and CL2). The typical values of systemic clearance scaled to a 70-kg patient for the 2 subpopulations were CL1 = 52.6 L/h and CL2 = 158 L/h. The parameters of the Hill function were 54.9 weeks for the postmenstrual age of 50% clearance maturation and 0.802 for the Hill coefficient. The typical values of distribution clearance and volumes of the central and peripheral compartments for a patient with a weight of 70 kg were Q = 40.5 L/h, VC = 7.63 L, and VT = 473 L, respectively. The value of the absorption rate constant from the epidural space was 0.0459/h, which suggests flip-flop pharmacokinetics of sufentanil after epidural administration.

To observe the morphology character of the anterior epidural space at the L4-5 disc level and to provide an anatomical basis for safely and accurately performing a percutaneous endoscopic lumbar discectomy (PELD). Fifty-five cases with L5 S1 lumbar disc herniation were included in this study, and cases with L4-5 disease were excluded. When the puncture needle reached the epidural space at the L5 S1 level, iohexol was injected at the pressure of 50 cm H2 O during the PELD, then C-Arm fluoroscopy was used to obtain standard lumbar frontal and lateral images. The widths of epidural space at the level of the L4 lower endplate, the L5 upper endplate, as well as the middle point of the L4-5 disc were measured from the lumbar lateral X-ray film. Epidural space at the L4-5 disc plane performs like a trapezium chart with a short side at the head end and a long side at the tail end in the lumbar lateral X-ray radiograph, while the average widths of epidural space were 10.2 ± 2.5, 12.3 ± 2.3, and 13.8 ± 2.6 mm at the upper, middle, and lower level of the L4-5 disc. Understanding the morphological characteristics of epidural space will contribute to improving the safety of the tranforaminal percutaneous endoscopy technique.

Pressure waveform analysis provides a reliable confirmatory adjunct to the loss-of-resistance technique to identify the epidural space during thoracic epidural anaesthesia, but its role remains controversial in lumbar epidural analgesia during labour. We performed an observational study in 100 labouring women of the sensitivity and specificity of waveform analysis to determine the correct location of the epidural needle. After obtaining loss-of-resistance, the anaesthetist injected 5 ml saline through the epidural needle (accounting for the volume already used in the loss-of-resistance). Sterile extension tubing, connected to a pressure transducer, was attached to the needle. An investigator determined the presence or absence of a pulsatile waveform, synchronised with the heart rate, on a monitor screen that was not in the view of the anaesthetist or the parturient. A bolus of 4 ml lidocaine 2% with adrenaline 5 μg.ml-1 was administered, and the epidural block was assessed after 15 min. Three women displayed no sensory block at 15 min. The results showed: epidural block present, epidural waveform present 93; epidural block absent, epidural waveform absent 2; epidural block present, epidural waveform absent 4; epidural block absent, epidural waveform present 1. Compared with the use of a local anaesthetic bolus to ascertain the epidural space, the sensitivity, specificity, positive and negative predictive values of waveform analysis were 95.9%, 66.7%, 98.9% and 33.3%, respectively. Epidural waveform analysis provides a simple adjunct to loss-of-resistance for confirming needle placement during performance of obstetric epidurals, however, further studies are required before its routine implementation in clinical practice.

Aim Depressed skull fracture is a neurosurgical emergency. Surgical treatment usually requires a sizeable scalp incision and burr hole with or without craniotomy for reduction. However, depressed skull fracture in neonates, or ‘ping pong’ fracture, is an uncommon clinical condition, occurring in approximately 4–10 in 100 000 live births. No standard treatment is established for depressed skull fracture in neonates. With a minimally-invasive technique, a good surgical outcome can be achieved with minimal blood loss and no bone loss. Patients and Methods A full-term, neonatal girl presented with spontaneous ‘ping pong’ fracture after a smooth, normal vaginal delivery. The anterior fontanelle was full. Computed tomography of the brain showed right parietal depressed skull fracture with sulci effacement, obliteration of the lateral ventricle and midline shift. Skull fracture reduction was performed with the bone elevation technique via access to the coronal suture without a burr hole or craniotomy. Results A small stab wound incision was made over the right coronal suture at the lateral edge of the anterior fontanelle. This site was in close proximity to the anterior margin of the depressed skull fracture. With access to the coronal suture and dissection in the epidural space, reduction was achieved intraoperatively by elevation of the inner table of the skull bone. Blood loss was minimal, and there was no bone loss. The clinical outcome was excellent at 1-week, 3-months’, 1-year and 18-months’ follow up. Conclusion For neonatal depressed skull fractures with clinical and radiographic evidence of a mass effect requiring surgical intervention, elevation with no burr hole is a good technique for bone reduction with minimal blood loss and no bone loss.

Objectives The primary objective of this case report was to demonstrate the unilateral distribution of the low volume injectate given in the epidural space when paramedian interlaminar approach is utilized under computed tomography guidance. Methods This was a case report on a single patient with history of unilateral epidural contrast distribution under fluoroscopy views, who presented with bilateral lumbar radicular symptoms, and underwent epidural injections via bilateral paramedian interlaminar approach under computed tomography guidance. Multiple-level computed tomography scans were obtained for demonstration purposes. Results There was primarily unilateral distribution of low–volume injectate in the epidural space when paramedian interlaminar approach is utilized.

An acute extrusion of non-degenerated nucleus pulposus material through a tear in the annulus fibrosus can occur after sudden changes of intradiscal pressure and biomechanics; for example, during vigorous exercise, running, jumping. This type of intervertebral disc extrusion can be characterised as compressive or non-compressive and is more commonly recognised and studied as the cause of acute myelopathy in dogs and less frequently in cats.1–6 The term acute non-compressive nucleus pulposus extrusion was proposed to indicate when the extruded hydrated (as a description of non-degenerated) nucleus pulposus contuses the spinal cord and dissipates within the epidural space without significant spinal cord compression.2 Other terms have been used to describe this type of intervertebral disc extrusion including: high-velocity low-volume disc extrusion, traumatic disc extrusion, dorsolateral intervertebral disc explosion, traumatic disc prolapse and, erroneously, Hansen type III intervertebral disc disease.1,2,4,7 From all the terms used, the one that ideally should be avoided is Hansen type III as Hansen described intervertebral disc degenerations (type I and type II) and this particular type of disc disease is non-degenerated and, moreover, it was never described by Hansen.8 A new study by Ros and colleagues9 on this type of intervertebral disc extrusion, summarised on page 594 of this week’s issue of Vet Record , uses the term acute hydrated non-compressive nucleus pulposus …

The myodural bridge was proposed initially in 1995. The myodural bridge is a connective tissue bridge that connects a pair of deep muscles at the suboccipital region to the dura mater. There have been numerous studies concerning the morphology and function of the myodural bridge. To determine whether a myodural bridge exists in reptiles, six Siamese crocodiles were investigated using gross anatomy dissection and P45 sheet plastination technologies. As a result, we demonstrated that the posterior occipital muscles of the Siamese crocodile are directly or indirectly connected to the proatlas, atlas, and intermembrane between them. Multiple trabeculae existing in the posterior epidural space extended from the ventral surface of the proatlas, atlas, and intermembrane between them to the dorsal surface of the spinal dura mater. This study showed that the posterior occipital muscle in the suboccipital region of the Siamese crocodile is connected to the spinal dura mater through the proatlas, atlas, and the trabeculae. In conclusion, a myodural bridge-like structure exists in reptiles. This connection may act as a pump to provide cerebrospinal fluid (CSF) circulation at the occipitocervical junction. We hypothesize that a physiologic role of the Siamese crocodile's myodural bridge may be analogous to the human myodural bridge. Anat Rec, 299:1402-1408, 2016. © 2016 Wiley Periodicals, Inc.

REASONS FOR PERFORMING STUDY The large size of the adult horse prevents the use of advanced imaging modalities in most areas of the axial skeleton, including the lumbosacral vertebral column. Traditional imaging techniques are frequently unable to pinpoint the underlying pathology in horses with caudal back pain. In man, lumbosacral epiduroscopy is used to diagnose and treat subjects with chronic back and leg pain. This technique may close the diagnostic gap in horses with similar clinical signs. OBJECTIVES To evaluate the safety and feasibility of lumbosacral epiduroscopy in the standing adult horse. STUDY DESIGN Descriptive, experimental study. METHODS Seven adult horses weighing 504-578 kg were sedated and restrained in stocks in preparation for aseptic surgery. Vascular dilators of increasing size were inserted cranial to the first moveable vertebra caudal to the sacrum to facilitate a minimally invasive approach into the epidural space. A flexible video-endoscope was introduced and advanced as far as its 60-cm working length permitted. Pre-, intra- and post-operative plasma cortisol samples were collected, and neurological and lameness examinations were performed prior to and during the 2 weeks following the procedure. Post-mortem examinations were conducted in 5 of the 7 horses. RESULTS Standing lumbosacral epiduroscopy was well tolerated by all horses. The anatomic structures in the epidural space (dura mater, spinal nerve roots, fat and blood vessels) were followed as far cranial as the thoracolumbar region. No complications related to the procedure were noted in the 2-week monitoring period following epiduroscopy. Small, organised haematomas were identified in the sacral epidural space during necropsy in one horse. No abnormalities were seen in the other 4 animals. CONCLUSIONS Lumbosacral epiduroscopy can be performed safely in sedated standing horses. The procedure may become a valuable diagnostic tool in horses with caudal back or hindlimb pain of unknown origin.

Objectives We aimed to estimate the spread of injections for ultrasound-guided cervical nerve root blocks and to determine the optimal injectate volume required in this procedure. Methods A total of 32 ultrasound-guided injections (C5–C8) were made in 4 fresh cadavers. The target on each cervical root was the space between the posterior tubercle and the cervical root at the most proximal location possible on the sonogram. After ultrasound-guided needle insertion, 0.5 mL of a contrast medium was injected 4 times. The dye flow patterns were confirmed with fluoroscopy each time, and we recorded whether the contrast medium reached the dorsal root ganglion level or the epidural space. After the injections, the needle tip location was determined by computed tomography and image reconstruction. Results All injections produced typical neurograms. The contrast medium reached the dorsal root ganglion in 29 of 32 (90.6%) injections (mean ± SD, 0.84 ± 0.42 mL of contrast medium) and the epidural space in 10 of 32 (31.3%) injections (1.30 ± 0.54 mL of contrast medium). The mean distance between the needle tip and neural foramen was 9.64 ± 3.68 mm, and this distance correlated positively with the volume of contrast medium necessary to reach the dorsal root ganglion or the epidural space. Conclusions Ultrasound-guided cervical nerve root blocks show potential utility for targeting an anesthetic into the cervical root area. This study may be helpful for deciding the most appropriate volume for the procedure.

In our new experimental model of cervical stenosis without inflammation we have tested hypothesis that cranio-spinal communication impairment could lead to hydrocephalus development. Spinal and cranial cerebrospinal fluid (CSF) space separation was obtained with positioning of plastic semiring in epidural space at C2 level in cats. Brain ventricles planimetry, and CSF pressure recording in lateral ventricle (LV) and lumbar subarachnoid space (LSS) were performed in acute and subchronic experiments. In all experiments opening CSF pressures were normal. However, in acute experiments, an infusion of artificial CSF into the LV led to increase of CSF pressure and significant gradient pressure development between LV and LSS due to limited pressure transmission. After 3 or 6 weeks spinal cord atrophy was observed at the site of cervical stenosis, and pressure transmission from LV to LSS was improved as a consequence of spinal tissue atrophy. Planimetry of both the coronal brain slices and the ventricles’ surface showed that control ventricular surface was 0.6 ± 0.1% (n = 5), and 1.6 ± 0.2% (n = 4) in animals with subchronic cervical stenosis (P

Background Childbirth may cause the most severe pain some women experience in their lifetime. Epidural analgesia is an effective form of pain relief during labour and is considered to be the reference standard. Traditionally epidural analgesia has been delivered as a continuous infusion via a catheter in the epidural space, with or without the ability for the patient to supplement the analgesia received by activating a programmable pump to deliver additional top-up doses, known as patient-controlled epidural analgesia (PCEA). There has been interest in delivering maintenance analgesic medication via bolus dosing (automated mandatory bolus - AMB) instead of the traditional continuous basal infusion (BI); recent randomized controlled trials (RCTs) have shown that the AMB technique leads to improved analgesia and maternal satisfaction. Objectives To assess the effects of automated mandatory bolus versus basal infusion for maintaining epidural analgesia in labour. Search methods We searched CENTRAL, MEDLINE, Embase, the World Health Organization International Clinial Trials Registry Platform (WHO-ICTRP) and ClinicalTrials.gov on 16 January 2018. We screened the reference lists of all eligible trials and reviews. We also contacted authors of included studies in this field in order to identify unpublished research and trials still underway, and we screened the reference lists of the included articles for potentially relevant articles. Selection criteria We included all RCTs that compared the use of bolus dosing AMB with continuous BI for providing pain relief during epidural analgesia for labour in women. Data collection and analysis We used the standard methodological procedures expected by Cochrane. Our primary outcomes were: risk of breakthrough pain with the need for anaesthetic intervention; risk of caesarean delivery; risk of instrumental delivery. Secondary outcomes included: duration of labour; local anaesthetic consumption. We used GRADE to assess the certainty of evidence for each outcome. Main results We included 12 studies with a total of 1121 women. Ten studies enrolled healthy nulliparous women only and two studies enrolled healthy parous women at term as well. All studies excluded women with complicated pregnancies. There were variations in the technique of initiation of epidural analgesia. Seven studies utilized the combined spinal epidural (CSE) technique, and the other five studies only placed an epidural catheter without any intrathecal injection. Seven studies utilized ropivacaine: six with fentanyl and one with sufentanil. Two studies used levobupivacaine: one with sufentanil and one with fentanyl. Three used bupivacaine with or without fentanyl. The overall risk of bias of the studies was low. AMB probably reduces the risk of breakthrough pain compared with BI for maintaining epidural analgesia for labour (from 33% to 20%; risk ratio (RR) 0.60; 95% confidence interval (CI) 0.39 to 0.92, 10 studies, 797 women, moderate-certainty evidence). AMB may make little or no difference to the risk of caesarean delivery compared to BI (15% and 16% respectively; RR 0.92; 95% CI 0.70 to 1.21, 11 studies, 1079 women, low-certainty evidence). AMB may make little or no difference in the risk of instrumental delivery compared to BI (12% and 9% respectively; RR 0.75; 95% CI 0.54 to 1.06, 11 studies, 1079 women, low-certainty evidence). There is probably little or no difference in the mean duration of labour with AMB compared to BI (mean difference (MD) −10.38 min; 95% CI −26.73 to 5.96, 11 studies, 1079 women, moderate-certainty evidence). There is probably a reduction in the hourly consumption of local anaesthetic with AMB compared to BI for maintaining epidural analgesia during labour (MD −1.08 mg/h; 95% CI −1.78 to −0.38, 12 studies, 1121 women, moderate-certainty evidence). Five out of seven studies reported an increase in maternal satisfaction with AMB compared to BI for maintaining epidural analgesia for labour; however, we did not pool these data due to their ordinal nature. Seven studies reported Apgar scores, though there was significant heterogeneity in reporting. None of the studies showed any significant difference between Apgar scores between groups. Authors' conclusions There is predominantly moderate-certainty evidence that AMB is similar to BI for maintaining epidural analgesia for labour for all measured outcomes and may have the benefit of decreasing the risk of breakthrough pain and improving maternal satisfaction while decreasing the amount of local anaesthetic needed.

Summary Purpose For caudal epidural analgesia, the needle is inserted at a site where vessels are abundant. To avoid complications related to intravascular administration of the local anesthetic, epinephrine is usually added, but there is no evidence about the safety of epidural administration of epinephrine in pediatric patients. The objective of this study was to assess the changes in epidural blood flow after epidural injection of epinephrine in young rats. Methods With approval of the local ethics committee, four young Sprague–Dawley rats weighing 110–120 g were investigated. The rats were anesthetized with isoflurane via a mask. After there was no escape reaction to pain, an arterial catheter, epidural blood flow monitor (Laser Doppler blood flow ALF 21; ADVANCE Corp.), and caudal epidural catheter were inserted while the rats remained under general anesthesia. Exactly, 10 μl of 1 : 1000 epinephrine was then infused, followed by measurement of the blood pressure and epidural blood flow. After the recovery of the blood pressure and epidural blood flow to baseline, 10 μl of saline was infused through the epidural catheter. The blood pressure and epidural blood flow were then measured again. Results One rat was excluded because epinephrine was inadvertently injected into the epidural vessels. Therefore, three rats were investigated in this experiment. Blood flow in the epidural space showed no change after the injection of saline. When epinephrine was administered into the epidural space, epidural blood flow decreased immediately and low flow persisted for 6–15 min. The reduction of blood flow was not very great, being only 8–14%, so there was no risk of spinal ischemia which would require 60–80% reduction. Conclusion Administration of epinephrine into the epidural space was safe in young rats. While reduction of epidural blood flow was observed, there was no spinal ischemia.

Post-laminectomy/laminotomy epidural fibrosis (EF) has been implicated as an important cause of failed back syndrome (FBS). The various clinical approaches used to control EF yield mixed outcomes. Cross-linked hyaluronic acid hydrogel (cHA) was synthesized to increase mechanical stability and residence time. We evaluated the therapeutic attenuation of proliferative EF in laminectomy/laminotomy groups treated and not treated with cHA. A bilateral T11-L1 total laminectomy or unilateral T12 laminotomy was done on four groups (n = 10 each) of Sprague-Dawley rats and then histologically examined 2 months post-surgery: (I) laminectomy group treated with and (II) not treated with cHA, (III) laminotomy group treated with and (IV) not treated with cHA. The grade of EF, the diameters within the spinal canal, dura mater thickness, and the area of the epidural space, subarachnoid space, and conus medullaris space were assessed. The cHA-treated subgroups (I, III) had a significantly lower grade of EF, thinner dura mater, and larger epidural and subarachnoid spaces than did the control subgroups (II, IV) (p

Summary Reasons for performing study Back pain is a common cause of gait alterations and poor performance in horses, but the available imaging modalities are frequently insufficient to isolate the underlying pathology. In human patients, epidural endoscopy (epiduroscopy) is successfully used to diagnose and treat challenging cases of lower back pain. Endoscopy of the cervical epidural space has previously been reported in anaesthetised horses. Objectives To develop a technique for lumbosacral epiduroscopy in standing horses and to describe the endoscopic anatomy of the lumbosacral epidural space. Study design Pilot study to assess the feasibility of lumbosacral epiduroscopy in 5 horse cadavers. Methods The cadavers of 5 horses, weighing 457–694 kg (mean, 570 kg), were suspended in an upright position. Vascular dilators of increasing size were inserted between the first 2 moveable vertebrae caudal to the sacrum to create a minimally invasive approach into the epidural space. A flexible videoendoscope was introduced and advanced as far cranially as the length of the endoscope permitted. The lumbosacral epidural space underwent gross necropsy examination following the procedure. Results The endoscope was successfully inserted into the epidural space in all horses. Saline injection through the working channel of the endoscope allowed the following anatomical structures to be seen: dura mater, left and right lumbosacral spinal nerves, cauda equina, epidural fat, connective tissue and blood vessels. Using the 60 cm working length of the endoscope, the epidural space could be examined as far cranial as L3–T18, depending on the size of the horse. No gross damage to epidural neurovascular structures was observed on necropsy examination. Conclusion Lumbosacral epiduroscopy is technically feasible in standing horses and may become a valuable diagnostic tool in horses with caudal back or limb pain of unknown origin. Studies in live horses will be necessary to evaluate the safety of the procedure.

Summary The aim of this randomised study was to compare the incidence of intravascular injections during S1 transforaminal epidural steroid injection performed in the anteroposterior and oblique views. We also compared epidural spread patterns of contrast media, which included 201 injections at the S1 level. The overall incidence of intravascular injection during S1 transforaminal epidural steroid injection in the anteroposterior view was 29% (29/99), significantly higher than in the oblique view (11%, 11/102, p = 0.001). There were no significant differences between the two groups for epidural spread of contrast media in cases where intravascular injections did not occur (p = 0.77). Performing S1 transforaminal epidural steroid injection in the oblique view rather than the anteroposterior view reduces the risk of intravascular injections.

Background Accidental dural puncture (ADP) and post-dural puncture headache (PDPH) are important complications of obstetric regional anesthesia. Inserting the catheter intrathecally after ADP to prevent PDPH has gained popularity. Nonetheless, data on the effect of an intrathecal catheter on PDPH and epidural blood patch (EBP) rates are mixed. Our primary objective was to examine if spinal catheterization reduces the incidence of PDPH after ADP in obstetric patients. Methods Anesthetic records of 29,749 regional blocks performed between January 1997 and July 2013 were analyzed retrospectively. In all blocks containing an epidural component, 18-gauge epidural needles were used. All patients who experienced a witnessed ADP or PDPH without ADP were identified. Data from patients with or without a prolonged spinal catheter were compared. Results There were 128 events of witnessed ADP (0.43%). Following known ADP, 39 women had an epidural catheter placed at a different level and 89 had an intrathecal catheter (20-gauge) for at least 24 h. Sixty-one patients developed PDPH after observed ADP (48%). Prolonged intrathecal catheter placement significantly reduced the incidence of PDPH after ADP to 42% compared with 62% in those who have the catheter re-sited epidurally [odds ratio = 2.3 (95% confidence interval 1.04–4.86); P = 0.04]. Conclusions The incidence of ADP, PDPH and blood patching is similar with previously published studies. After witnessed ADP, inserting the epidural catheter intrathecally significantly reduced the incidence of PDPH.

Spontaneous pneumomediastinum is usually secondary to alveolar rupture in the pulmonary interstitium, associated with subcutaneous emphysema and occasionally with pneumothorax, but is rarely associated with pneumorrhachis. The leaked air into the pulmonary perivascular interstitium follows the path of least resistance from the mediastinum to the fascial planes of the neck. Air freely communicates via the neural foramina and collects in the epidural space. Pneumorrhachis is defined as the presence of air in the spinal canal, either in the intradural and/or extradural spaces. It is a very rare clinical entity and mostly asymptomatic, hence most probably underdiagnosed. Many pathological and physiological events can lead to alveolar rupture, and these clinical findings can be related to various, mainly traumatic and iatrogenic etiologies. Herein we report three cases of pneumomediastinum, subcutaneous emphysema, interstitial emphysema and pneumorrhachis in two cases, which were related to rhinovirus, human bocavirus and respiratory syncytial virus infection.

Epidural injections are commonly performed blindly in veterinary medicine. The aims of this study were to describe the lumbosacral ultrasonographic anatomy and to assess the feasibility of an ultrasound-guided epidural injection technique in dogs. A cross sectional anatomic atlas of the lumbosacral region and ex vivo ultrasound images were obtained in two cadavers to describe the ultrasound anatomy and to identify the landmarks. Sixteen normal weight canine cadavers were used to establish two variations of the technique for direct ultrasound-guided injection, using spinal needles or epidural catheters. The technique was finally performed in two normal weight cadavers, in two overweight cadavers and in five live dogs with radiographic abnormalities resulting of the lumbosacral spine. Contrast medium was injected and CT was used to assess the success of the injection. The anatomic landmarks to carry out the procedure were the seventh lumbar vertebra, the iliac wings, and the first sacral vertebra. The target for directing the needle was the trapezoid-shaped echogenic zone between the contiguous articular facets of the lumbosacral vertebral canal visualized in a parasagittal plane. The spinal needle or epidural catheter was inserted in a 45° craniodorsal-caudoventral direction through the subcutaneous tissue and the interarcuate ligament until reaching the epidural space. CT examination confirmed the presence of contrast medium in the epidural space in 25/25 dogs, although a variable contamination of the subarachnoid space was also noted. Findings indicated that this ultrasound-guided epidural injection technique is feasible for normal weight and overweight dogs, with and without radiographic abnormalities of the spine.

BACKGROUND AND OBJECTIVES Our objective was to assess plasma sufentanil concentrations and postinfusion pharmacokinetics in infants receiving 0.2% ropivacaine with sufentanil as a continuous epidural infusion for postoperative pain relief. METHODS With consent of local ethics committee and informed parental consent, 20 infants 3-36 months old (m.o.) (median 9.3 m.o., 9.0 [3.5-15] kg, ASA PS I/II) were enrolled. Epidural catheter was placed under general anesthesia in L3-L4, L4-L5, or L2-L3 interspace and threaded not farther than 4 cm into epidural space. After initial bolus of 0.2% ropivacaine, 0.5 ml·kg(-1) and sufentanil 200 ng·kg(-1) , continuous infusion of 0.2% ropivacaine, 0.3 mg·kg(-1) ·h(-1) with sufentanil 112 ng·kg(-1) ·h(-1) was started. For the postoperative period, sufentanil dose was reduced to 37 ng·kg(-1) ·h(-1) . Blood samples were drawn at the end of surgery, 24 h later, by the end of 2nd day of infusion and after 3, 6, and 18 h from the end of infusion. Sufentanil was measured using liquid-liquid extraction (LLE) procedure and HPLC-MS/MS method with LOQ = 5 pg·ml(-1) . RESULTS AND CONCLUSIONS Elimination of sufentanil following epidural administration was very slow, with MRT = 28.25 [18.36-44.75] h and t1/2 MRT = 19.57 [12.72-31.01] h. In infants, during a long-term infusion of sufentanil with ropivacaine, the opioid concentration in plasma increases during the postoperative infusion itself, then increases even further after discontinuation of the infusion, in some cases reaching the values consistent with a potential risk of respiratory depression. Meticulous monitoring of the infants' vital signs is therefore mandatory not only during the infusion, but also for several hours after its discontinuation.

Summary We have developed an ultrasound probe through the centre of which an epidural needle can pass, intended to reduce the rate of contact between bone and needle during epidural insertion. We tested the ability of this probe to identify the lumbar interspace, using A-mode ultrasound, in a submerged plastic model, a porcine phantom and five human volunteers. In the plastic model, the minimum echo representing the interspace was only 8.8% of the maximum echo from the ‘bone’. In the porcine model, the echo variations between the interspace and L3 were up to 48% and the needle was safely inserted into the interspace without bone contact under guidance. The human study also showed that the maximum bone echo was at least three times stronger than the interspace echo. Axial ultrasound guidance, with the needle passing through the probe, offers a method for reducing bone contact during epidural insertion.