Smart syringe using actuator and force sensor for epidural anesthesia injection

The anesthesia process in the epidural space is quite difficult as it requires a high level of skill. Therefore, a medical accident occurs, and intensive training is required. In order to reduce these medical accidents, medical technology is being developed, which provides safe and accurate treatment services. This paper proposes a smart syringe design for safe and accurate anesthesia in the epidural space. The smart syringe is designed to measure the electrical sensing waveform by using a sensor instead of the sense of the hand during anesthesia and show the position of the needle through external monitoring. To design a smart syringe, a force sensor, actuator, and CPU were used, and a 3D printer was used to produce the outer shape. An animal test was conducted to evaluate the performance test of the smart syringe, and satisfactory results were obtained by measuring the needle insertion process of the smart syringe and the position of the needle through the animal experiment.

Comparative Evaluation of Clonidine as an Adjunct to Ropivacaine for Caudal Block Anaesthesia in Children Undergoing Sub-Umbilical Surgeries

BACKGROUND Studies suggest that clonidine can improve the duration of analgesia, quality of pain control when used with ropivacaine for caudal blocks in children. This study was designed to understand the effects of caudally administered ropivacaine 0.25 % (1ml/kg) alone and ropivacaine 0.25 % (1ml/kg) with clonidine 2 mcg/kg, in children between 2- 10 years. METHODS Sixty children posted for various sub-umbilical surgical procedures were included after written informed consent and ethics committee approval. Children were randomly divided into 2 groups of 30 each: Group R —ropivacaine 0.25 % 1 ml/kg into caudal epidural space and Group RC—ropivacaine 0.25 % 1 ml/kg and clonidine 2 mcg/kg into caudal epidural space. RESULTS The mean age of patients was similar with no statistical difference (4.83 vs 5.36, P = 0.3353). The duration of anaesthesia was significantly longer in the RC group (544.83 minutes vs 268.00 minutes, P < 0.0001). The effect size was very high (Cohen d=23.86). The pain score was comparable up to 1 hour for the two groups. But 2 hours later, the pain scores were significantly lower for the ropivacaine and clonidine groups. The effect on motor blockade was similar in both groups with no motor blockade at 4 hours follow up. 5 cases of urinary retention were seen in the study with no statistically significant difference in terms of complication rate between the two groups. No case of hypotension or bradycardia was seen. There was a significant difference between the two groups in terms of cardiovascular parameters (HR, SBP, DBP) after administration of drugs. CONCLUSIONS The addition of clonidine to ropivacaine for caudal blocks in children was associated with better quality of pain control and a longer duration of analgesia without any additional motor blockade. There was no significant difference seen in terms of complication. KEY WORDS Analgesia Duration, Caudal Analgesia, Clonidine, Pain Control, Ropivacaine.

Fiber Optic Distributed Sensing Network for Shape Sensing-Assisted Epidural Needle Guidance

Epidural anesthesia is a pain management process that requires the insertion of a miniature needle through the epidural space located within lumbar vertebrae. The use of a guidance system for manual insertion can reduce failure rates and provide increased efficiency in the process. In this work, we present and experimentally assess a guidance system based on a network of fiber optic distributed sensors. The fibers are mounted externally to the needle, without blocking its inner channel, and through a strain-to-shape detection method reconstruct the silhouette of the epidural device in real time (1 s). We experimentally assessed the shape sensing methods over 25 experiments performed in a phantom, and we observed that the sensing system correctly identified bending patterns typical in epidural insertions, characterized by the different stiffness of the tissues. By studying metrics related to the curvatures and their temporal changes, we provide identifiers that can potentially serve for the (in)correct identification of the epidural space, and support the operator through the insertion process by recognizing the bending patterns.

Anatomy of the lumbar interspinous ligament: findings relevant to epidural insertion using loss of resistance

Background and objectivesThe ‘loss of resistance’ technique is used to determine entry into the epidural space, often by a midline needle in the interspinous ligament before the ligamentum flavum. Anatomical explanations for loss of resistance without entry into the epidural space are lacking. This investigation aimed to improve morphometric characterization of the lumbar interspinous ligament by observation and measurement at dissection and from MRI.MethodsMeasurements were made on 14 embalmed donor lumbar spines (T12 to S1) imaged with MRI and then dissected along a tilted axial plane aligned with the lumbar interspace.ResultsIn 73 interspaces, median (IQR) lumbar interspinous plus supraspinous ligament length was 29.7 mm (25.5–33.4). Posterior width was 9.2 mm (7.7, 11.9), with narrowing in the middle (4.5 mm (3.0, 6.8)) and an anterior width of 7.3 mm (5.7, 9.8).Fat-filled gaps were present within 55 (75%). Of 51 anterior gaps, 49 (67%) were related to the ligamenta flava junction. Median (IQR) gap length and width were 3.5 mm (2.5, 5.1) and 1.1 mm (0.9, 1.7).Detection of gaps with MRI had 100% sensitivity (95% CI 93.5 to 100), 94.4% specificity (72.7, 99.9), 98.2% (90.4, 100) positive predictive value and 100% (80.5, 100) negative predictive value against dissection as the gold standard.ConclusionsThe lumbar interspinous ligament plus supraspinous ligament are biconcave axially. It commonly has fat-filled gaps, particularly anteriorly. These anatomical features may form the anatomical basis for false or equivocal loss of resistance.

Comparison of landmark and real-time ultrasound-guided epidural catheter placement in the pediatric population: a prospective randomized comparative trial

Background: Epidural block placement in pediatric patients is technically challenging for anesthesiologists. The use of ultrasound (US) for the placement of an epidural catheter has shown promise. We compared landmark-guided and US-guided lumbar or lower thoracic epidural needle placement in pediatric patients.Methods: This prospective, randomized, comparative trial involved children aged 1–6 years who underwent abdominal and thoracic surgeries. Forty-five children were randomly divided into two groups using a computer-generated random number table, and group allocation was performed by the sealed opaque method into either landmark-guided (group LT) or real-time ultrasound-guided (group UT) epidural placement. The primary outcome was a comparison of the procedure time (excluding US probe preparation). Secondary outcomes were the number of attempts (re-insertion of the needle), bone contacts, needle redirection, skin-to-epidural distance using the US in both groups, success rate, and complications.Results: The median (interquartile range [IQR]) time to reach epidural space was 105.5 (297.0) seconds in group LT and 143.0 (150) seconds in group UT; P = 0.407). While the first attempt success rate was higher in the UT group (87.0% in UT vs. 40.9% in LT; P = 0.004), the number of bone contacts, needle redirections, and procedure-related complications were significantly lower. Conclusions: The use of US significantly reduced needle redirection, number of attempts, bone contact, and complications. There was no statistically significant difference in the time to access the epidural space between the US and landmark technique groups.

Symptomatic interdural cerebrospinal fluid collections after surgery for idiopathic spinal cord herniation: illustrative case

BACKGROUND Idiopathic spinal cord herniation (ISCH) is very rare. Some reports have described postoperative ventral cerebrospinal fluid (CSF) collections in patients with ISCH; however, such collections are asymptomatic in most patients, and there is no consensus regarding whether they are part of the natural history or a complication. OBSERVATIONS A 30-year-old man with ISCH underwent direct closure of a duplicated dura mater. Eight months postoperatively, he developed reworsening of right lower limb paresis and new severe right arm pain and paresis. Three-dimensional magnetic resonance imaging revealed ventral CSF collections, which the authors judged as the responsible lesions. The authors initially considered these collections to be present in the epidural space, extradurally compressing the dural sac and resulting in myelopathy. An epidural blood patch failed; however, a CSF drainage test resulted in dramatic improvement. The authors therefore determined that the CSF collections were located in the interdural space, not the epidural space. A lumboperitoneal (LP) shunt was performed to reduce the CSF pressure. The patient’s symptoms improved immediately postoperatively. He had developed no recurrence of symptoms 6 months after surgery. LESSONS Ventral interdural CSF collections after ISCH surgery can cause reworsening of myelopathy and may be cured by a LP shunt to control CSF pressure.

Does Paramedian Approach Preferentially Secure Optimal Drug Delivery Onto Ventral Epidural Space and Subsequent Superior Clinical Efficacy Over a Dorsal Midline Approach During Cervical Interlaminar Epidural Injection?

BACKGROUND: There is paucity in the literature directly comparing the clinical results between the paramedian and the midline interlaminar cervical epidural injections. OBJECTIVE: To compare the proportion of ventral epidural spread of injectate and consequent clinical outcome between the paramedian and midline approach during interlaminar epidural injection in patients with axial neck and/or interscapular pain triggered from the underlying cervical spine pathologic condition. STUDY DESIGN: Retrospective study. SETTING: Primary pain clinic and spine hospital. METHODS: Two hundred and twenty-three patients with axial neck and/or interscapular pain due to cervical problem underwent interlaminar epidural injection through either a paramedian approach (PM group, n = 93) or a midline approach (ML group, n = 130). We compared the portion of ventral epidural filling, Numeric Rating Scale (NRS), and McNab criteria between both groups. The NRS and McNab criteria were also separately compared between the ventrally spread (VS) group and non-ventral spread (non-VS) group inside each PM and ML group, respectively, at 2 weeks and 10 weeks post-injection. RESULTS: The PM group showed a significantly higher proportion of ventral spread, successful NRS reduction, and satisfactory McNab criteria than the ML group at 10 weeks. In the PM group, the VS group showed the same results as above compared to the non-VS group. LIMITATIONS: A retrospective analysis based on the relatively short-term follow-up period clinical results. CONCLUSIONS: The paramedian approach showed the better direct injectate transfer over the ventral epidural space and subsequently superior clinical efficacy for the patients suffering from axial neck and/or interscapular pain secondary to cervical spine problems. KEY WORDS: Cervical disease, epidural injection, interlaminar, paramedian, midline, ventral epidural spread, Numeric Rating Scale, McNab criteria

Correlation of skin epidural distance and posterior epidural space depth with age, weight, height, BMI, abdominal girth and position of the patient: A prospective randomised study

Lumbar epidural block is a commonly used procedure for providing anaesthesia, post-operative analgesia in all groups of patients irrespective of age, sex, weight and height of the patients. The knowledge of posterior space is important in view of the fact that this is the space where drugs for epidural anaesthesia/ analgesia are used. The knowledge of variability of this space with physical parameters of the patient, help us in reducing the incidence of total spinal anaesthesia.Two hundred adult patients in the age group of 20-60 years requiring subarachnoid block were chosen for the study. Using 22G Quincke spinal needle, epidural space was identified and skin epidural distance was measured. Proceeding the spinal needle further, causes needle to lie in subarachnoid space. The skin subarachnoid distance was measured. The difference between skin-subarachnoid distance and skin epidural distance denoted the posterior epidural space width. Its correlation with physical parameters was studied.Mean skin epidural distance was 4.30 ±0.57 in lateral position and 4.05 ± 0.57 in sitting position, the difference being statistically significant. (P= 0.002). There was positive correlation between skin epidural distance with weight, BMI and abdominal girth of the patient. Mean posterior epidural space depth was 0.468+14 cm in lateral position and 0.459+0.14 cm in sitting position, the difference being statistically insignificant. There was a positive correlation between posterior epidural space depth and height of the patient.The skin epidural distance varies with weight, BMI, abdominal girth and position of the patient. The posterior epidural space depth varies with the height of the patients.