Coiling of lumbar epidural catheters

Removing knotted or stuck epidural catheters: a systematic review of case reports

BACKGROUND

The knotting or in vivo entrapment of epidural catheters is an uncommon but challenging issue for anesthesiologists. This study aimed to identify the possible causes behind entrapped epidural catheters and the effective methods for their removal.

METHODS

A systematic review of relevant case reports and series was conducted using the patient/population, intervention, comparison and outcome framework and keywords such as "epidural," "catheter," "knotting," "stuck," "entrapped," and "entrapment." The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement was followed, and the review protocol was registered with International Prospective Register for Systematic Reviews (CRD42021291266).

RESULTS

The analysis included 59 cases with a mean depth of catheter insertion from the skin of 11.825 cm and an average duration of 8.17 h for the detection of non-functioning catheters. In 27 cases (45.8%), a radiological knot was found, with an average length of 2.59 cm from the tip. The chi-squared test revealed a significant difference between the initial and final positions of catheter insertion (P = 0.049).

CONCLUSIONS

Deep insertion was the primary cause of epidural catheter entrapment. To remove the entrapped catheters, the lateral decubitus position should be attempted first, followed by the position used during insertion. Based on these findings, recommendations for the prevention and removal of entrapped catheters have been formulated.

Intrapartum Subarachnoid Migration of Epidural Catheter Inserted for Labour Analgesia: A Case Report

Epidural analgesia is commonly used for pain management during labor. Owing to the blind nature of the insertion of the catheters, they are prone to migration to various spaces intra-spinally, which may result in a multitude of complications. We present a case of a 32-year-old lady who was admitted with labor pain, and an epidural catheter was inserted for labor analgesia. Five hours after insertion, she developed sudden motor and sensory impairment suggestive of subarachnoid migration of the catheter. The diagnosis, management, and risks associated with delay in the identification of this potentially fatal complication are discussed.

Prediction of Successful Epidural Catheter Placement by a ‘Cold Test’

We tested the hypothesis that the patients’ feeling of cold sensation down the back during epidural drug administration through the epidural catheter was a reliable predictor of correct epidural catheter placement. In a prospective study of 80 patients, an epidural catheter was placed in the lumbar epidural space. During epidural drug injection, patients were asked to report feeling of the cold sensation in their back by pressing a bell. After 15 minutes, the patients were assessed for cold sensation in the thoracic to sacral dermatomes bilaterally and the dermatomal block recorded. Of 80 patients, three had inadvertent dural puncture. Seventy-two of 77 patients reported feeling cold sensation in their back during local anaesthetic injection, and all had successful epidural blockade. Of the five patients who did not report any cold sensation, three had failed epidural block and two successful epidural block. There were no false positive results. Of three patients who had inadvertent dural puncture and had normal saline 5 ml injected through the Tuohy needle, none reported cold sensation. The perception of cold sensation in the back during epidural administration of a test dose and/or subsequent full dose of local anaesthetic is useful in predicting successful epidural catheter placement.

The Differential Flow of Epidural Local Anaesthetic via Needle or Catheter: A Prospective Randomized Double-blind Study

The extent of epidural anaesthesia and pattern of spread of contrast medium, using different injection techniques, has not been well documented. Therefore, in this prospective, randomized, double-blind study, the extent of anaesthesia and pattern of spread of contrast medium following an epidural bolus injection, via either a Tuohy needle or an epidural catheter, were compared.

The study had two parts. In the first, 59 of 79 patients scheduled for a lower extremity operation under epidural anaesthesia were randomly allocated to one of the two groups. Anaesthesia was achieved with an epidural injection of 10 to 15 ml (including a 3 ml test dose) of 0.75% ropivacaine and fentanyl 25 μg via either a Tuohy needle (Group N, n=31) or a catheter (Group C, n=28). The level of sensory anaesthesia was recorded. In the second part, the remaining 20 patients were randomized to initially receive 5 ml of contrast medium via either a Tuohy needle (Group NE, n=10) or a catheter (Group CE, n=10). The extent of spread was recorded radiologically.

Unilateral or missed blocks and additional dose requirement were absent in Groups N and C. No differences were found in the extent of sensory anaesthesia or the spread of contrast medium. Twenty per cent of catheter tips lay outside the lateral margins of the vertebral bodies.

We found that an epidural bolus injection, via either a Tuohy needle or a catheter, made no difference in regard to spread of local anaesthetic or contrast medium in the epidural space.

Partial displacement of epidural catheter after patient position change: A case report

Epidural catheter migration is a well-known cause of failed anesthesia and complications. One of the factors that affect catheter movement is when patients change their position after skin fixation. We report a case of an epidural catheter placed without evidence of intravascular or subdural insertion that produced an insufficient block. A 36-year-old woman presented for ankle surgery under epidural anesthesia. Epidural block was conducted at the L3-4 intervertebral space with a catheter threaded 3 cm into the epidural space with the patient in a back flexion and lateral position. The total volume of injected anesthetic was 28 mL, including a 3-mL test dose. The final anesthesia level was L1. The planned operation was completed without a pneumatic tourniquet. A postoperative C-arm fluoroscopic image revealed that 1 side hole of the catheter had moved out of the epidural space. We think that a positional change after catheter fixation was the reason for catheter outmigration leading to insufficient analgesia, which was incompatible with the amount of local anesthetic injected.

Lateral deviation of four types of epidural catheters from the lumbar epidural space into the intervertebral foramen

Background

During epidural anesthesia, the catheter tip occasionally deviates from the epidural space into the intervertebral foramen, resulting in inadequate anesthesia.

Methods

During postoperative plain radiography, iohexol was injected via the epidural catheter to determine its position and to observe the spread of the material. After exclusion of seven patients with catheters that migrated into the subcutaneous area and 25 patients with no evidence of the contrast medium, 415 patients were evaluated. We retrospectively compared patients to determine whether the incidence of deviation into the intervertebral foramen differed between four types of epidural catheters. We also investigated the load applied to the catheter tip using a Shimadzu Autograph AG-X-500 N-111 universal testing machine.

Results

Deviation of the epidural catheter into the intervertebral foramen was observed in eight and 33 patients in the Hakko and Perifix Soft tip catheter groups, respectively. The incidence of deviation was higher in the Perifix Soft tip catheter group, and lower in the FlexTip Plus and Perifix FX catheter groups. A rapid increase was observed in the force exerted on the tips of the Hakko and Perifix Soft tip catheters, while the force transmitted to the tips of the FlexTip Plus and Perifix FX catheters gradually increased and then reached a plateau at a low level.

Conclusions

The incidence of deviation was significantly lower with spiral-type catheters than with other types of catheters. This might be attributable to the gradual transmission of a lower level of force to the tip in spiral-type catheters.

Utility of transesophageal echocardiography in identifying spinal canal structures and epidural catheter position: a prospective observational study of intraoperative hemodynamics and postoperative analgesia

PURPOSE

The aims of this study were to determine the utility of transesophageal echocardiography (TEE) for identifying spinal canal structures and epidural catheter position and to assess the effect of catheter position on intraoperative hemodynamics and quality of postoperative analgesia.

METHODS

Twenty-six adult patients undergoing thoracic surgery were included in this prospective, observational study. An epidural catheter was inserted 7.5 cm or more into the thoracic epidural space using a midline approach and a loss-of-resistance technique. A pediatric TEE probe was inserted after induction of general anesthesia. It was used to identify the spinal canal structures, the catheter tip position in the epidural space, and the spread of injected local anesthetic. Intraoperative hemodynamics, postoperative visual analogue scale (VAS) pain scores, and the need for rescue epidural doses were recorded and compared between groups determined by their catheter position.

RESULTS

Two subjects were excluded from the study because of an intrathecally positioned epidural catheter. The remaining 24 subjects were divided into two groups based on TEE-determined epidural catheter position: posterior (Gr-P) or lateral (Gr-L). Spinal canal structures and the epidural catheter was successfully identified in all patients. The epidural catheter was located posteriorly in 20 (83%) patients and laterally in four (17%) patients. The spread of the local anesthetic was bilateral in all Gr-P patients, whereas it was unilateral in all but one of the Gr-L patients. Compared to Gr-P patients, Gr-L patients had higher heart rates and blood pressures at various time points after local anesthetic administration until the end of surgery (P = 0.02 to < 0.001). Postoperative VAS scores (P = 0.02) and the median number of rescue analgesic doses required during the intraoperative and postoperative periods were also higher in Gr-L patients (P < 0.001).

CONCLUSION

Transesophageal echocardiography reliably identified spinal canal structures and the position of epidural catheters in the epidural space in adult patients. Posteriorly located epidural catheters appear to provide better epidural analgesia than laterally situated catheters.

Epidural catheter design: history, innovations, and clinical implications

Epidural catheters have evolved during the past several decades, as clinicians and manufacturers have sought to influence the quality of analgesia and anesthesia and reduce the incidence of catheter-related complications. This evolution has allowed a transformation from single-shot to continuous-infusion techniques and resulted in easier passage into the epidural space, more extensive medication distribution, and ultimately, improved patient satisfaction. Particular catheter features, including the materials used, tip design, and orifice number and arrangement, have been associated with specific outcomes and provide direction for future development.

Direction of catheter insertion and the incidence of paresthesia during continuous epidural anesthesia in the elderly patients

Background

Continuous epidural anesthesia is useful for endoscopic urologic surgery, as mostly performed in the elderly patients. In such a case, it is necessary to obtain successful sacral anesthesia, and the insertion of epidural catheter in the caudad direction may be needed. However, continuous epidural catherization has been related to paresthesias. This study aimed to evaluate the effects of the direction of the catheter insertion on the incidence of paresthesias in the elderly patients.

Methods

Two hundred elderly patients scheduled for endoscopic urologic surgery were enrolled. The epidural catheter was inserted at L2-3, L3-4, and L4-5 using the Tuohy needle. In Group I (n = 100), the Tuohy needle with the bevel directed the cephalad during the catheter insertion. In Group II (n = 100), it directed the caudad. During the catheter insertion, an anesthesiologist evaluated the presence of paresthesias and the ease or difficulty during the catheter insertion.

Results

In Group I (n = 97), 15.5% of the patients had paresthesias versus 18.4% in Group II (n = 98), and there was no significant difference between the two groups. In paresthesia depending on the insertion site and the ease or difficulty during the catheter insertion, there were no significant differences between the two groups.

Conclusions

Our results concluded that the direction of epidural catheter insertion did not significantly influence the incidence of paresthesias in the elderly patients.

Near-infrared tracking system for epidural catheter placement: a feasibility study

BACKGROUND

Epidural catheters are routinely used in regional and obstetric anesthesia. The flexible catheter is advanced without imaging control into the epidural space, and coiling or kinking of the catheter may occur, compromising the effectiveness of epidural anesthesia. Potentially near-infrared (NER) light detection may help, tracking advancement of the catheter in the epidural space.

METHODS

Nonembalmed human cadavers donated to the University of Washington Willed Body program were placed prone. Catheters containing NER-emitting wire were introduced into the lumbar and thoracic epidural space. The progress of the emitting wire was tracked using the LumenVu NER guidance system, and the final location of the catheter was confirmed with fluoroscopy.

RESULTS

Total 12 attempts were made to place the catheter. In 7 cases (4 lumbar and 3 thoracic), good progression of the catheter in the epidural space was achieved with excellent visibility at low NER power levels. Maximum light intensity was registered when the catheter tip was found in the midline dorsal interlaminar position, as confirmed by fluoroscopy. The light intensity decreased while the catheter tip was traversing under the lamina. Poor progression of the catheter with negligible visibility of the tip at the highest NER level occurred in obese specimen (n = 2) or when the tip was in extraforaminal (n = 1), paramedian or paravertebral positions (n = 2).

CONCLUSIONS

Many variables such as obesity, paravertebral and extraforaminal catheter locations, and intervening bony structures can impede the application of NER technology for epidural catheter placements. Further optimization of the technology for clinical use is necessary.

Comparison of feasibility and safety of epidural catheterization between cranial and caudal lumbar vertebral segments in dogs

To compare the technical difficulty and safety of epidural catheterization between cranial and caudal lumbar region, thirteen dogs were randomly assigned to a cranial lumbar group (group CraL, n=6) or a caudal lumbar group (group CauL, n=6) depending on different epidural sites, and one dog was used as a negative control without catheterization. After general anesthesia, an epidural catheter was advanced 10 cm cranially from the interspace of L1-L2 in group CraL or from lumbosacral space in group CauL. Dogs were euthanized and catheter position and tip location were confirmed by laminectomy. Spinal cord samples were examined by macro- and microscopic observations. Success rate, time taken for epidural space confirmation and catheter insertion were compared, and overall technical difficulty was evaluated subjectively. Epidural catheter was inserted successfully in all dogs. Time needed from needle skin puncture to catheter placement and saline injection was 226 ± 63 and 229 ± 26 sec in groups CraL and CauL without significant differences. Three dogs in group CraL suffered subcutaneous blood, but no spinal cord injuries were found. Subjective evaluation score of the overall technical difficulty was slightly but significantly higher in group CraL than in group CauL (P=0.009). Epidural catheterization in cranial lumbar region could be performed as feasible and safe as that at the caudal lumbar vertebral region in medium or large dogs.

Accuracy of the epidural catheter position during the lumbar approach in infants and children: a comparison among L2-3, L3-4, and L4-5 approaches

Background

The aim of this study was to compare the accuracy of the position of the epidural catheter inserted from three different lumbar intervertebral spaces, L2-3, L3-4, and L4-5, in infants and children.

Methods

Seventy-five children were randomly allocated to 3 groups according to the epidural catheter insertion site (L2-3, L3-4, and L4-5). The epidural catheter tip was identified using 50% diluted Iohexol and fluoroscopy. The incidence of correct position was compared among the groups and between infants and children.

Results

The incidence of correct position was significantly higher in the L2-3 group as compared to the L3-4 and L4-5 groups (P = 0.023 and P = 0.046 respectively). The incidence of correct position was higher in infants compared to children (P = 0.017).

Conclusions

The L2-3 intervertebral space is preferable during epidural catheter insertion in children older than 1 year, but a low lumbar level should be considered in infants because they have a higher risk of neural damage.

Insertion length and resistance during advancing of epidural catheter

PURPOSE

The migration of an epidural catheter into the intravascular and subarachnoid spaces sometimes occurs. This study was designed to investigate where the resistance was felt during the advancing of the catheter into the epidural space and whether the length of catheter advanced in the epidural space affected the incidence of catheter migration.

METHODS

One hundred and twenty women, American Society of Anesthesiologists (ASA) 1 or 2, scheduled to undergo lower abdominal surgeries with epidural anesthesia were randomly assigned to two groups according to the length of the epidural catheter advanced; 4 cm (n = 60) or 8 cm (n = 60). The length where resistance to advancing the catheter was perceived was recorded in all patients, and the incidence of aspiration of blood or cerebrospinal fluid (CSF) was obtained. Further, the catheters removed 48 h after surgery were scrutinized for their bending sites.

RESULTS

Resistance was felt in 83 (69.2%) patients and the mean length in the epidural space at which resistance was found was 2.5 +/- 1.2 cm. Blood was aspirated in 9 (7.5%) patients when resistance to advancing the catheter was overcome, but CSF was aspirated in no patient. A distal bend was observed 2.4 +/- 1.3 cm from the tip of the catheter, and the sites of bending were correlated with the length where resistance was encountered. An additional proximal bend was observed in 35 (58%) patients in the 8-cm group, and in 2 patients (3%) in the 4-cm group (P < 0.001), probably due to coiling of the catheter.

CONCLUSION

At approximately 2.5 cm in the epidural space, advancing an epidural catheter causes resistance. Further advancing past this point may cause migration of the catheter into the vessels, or the coiling of the catheter.

The coiling length of thoracic epidural catheters: the influence of epidural approach angle

BACKGROUND

Thoracic epidural catheters are used for anaesthesia and postoperative analgesia. Usually, epidural catheters are placed without confirmation of their position despite frequent reports of complications as a result of malposition. In this study, we evaluated the threading length of thoracic epidural catheters without coiling and assessed the influence of two different epidural approach angles on the threading length without coiling.

METHODS

Eighty-three patients scheduled for thoracotomy were enrolled and randomly allocated into the acute angle group and the obtuse angle group. In both groups, skin insertion was performed at the T8-9 intervertebra level. Epidural access was performed under fluoroscopy using a paramedian approach at the T7-8 level in the acute angle group and at the T6-7 level in the obtuse angle group, and an end-hole 19-gauge epidural catheter was inserted. Coiling length, defined as the length of the catheter within the epidural space when any part of the catheter just begins to head caudally, was measured in both groups.

RESULTS

The coiling length was 7.4(4.4) cm (95% CI 6.0-8.7 cm) in the obtuse angle group compared with 4.9(3.3) cm (95% CI 3.8-6.0 cm) in the acute angle group (P = 0.005).

CONCLUSIONS

Approaching the thoracic epidural space with an obtuse approach angle provides longer coiling length. We recommend that an obtuse approach angle should be used to maximize the chance of the catheter reaching the intended level with minimum risk of coiling.

Identification of thoracic intervertebral spaces by means of surface anatomy: a magnetic resonance imaging study

BACKGROUND

Successful thoracic epidural analgesia depends on the sensory blockage of specific dermatomes following appropriate placement of the epidural catheter. This study aimed to ascertain how accurately anaesthesiologists identify thoracic intervertebral spaces, and whether counting from the prominent vertebra is easier than using the iliac crest as an anatomical landmark.

METHODS

Five anaesthesiologists attempted to locate one out of five consecutive intervertebral spaces (Th7-Th8 to Th11-Th12) on patients referred for magnetic resonance imaging of the vertebral column. The intended thoracic interspace and the counting reference point (C7-Th1 or L3-L4) were marked with oil capsules. The body mass index, gender and position of the patient were recorded. The exact capsule positions were determined by a radiologist after the study.

RESULTS

In 92 patients, 26.7% of the thoracic interspaces were correctly identified. The counting reference point was the only variable studied with a significant influence on error. The accuracy increased when the iliac crest was used as an anatomical landmark rather than the prominent vertebra (odds ratio, 0.29). The majority (76.4%) of all the incorrectly placed capsules were found cephalad to the intended level.

CONCLUSION

We recommend that the caudal of two to three possible interspaces should be used when placing an epidural catheter in the thoracic spine. Because of the inaccurate localization of the thoracic intervertebral spaces, documentation should state the site of puncture as being in the upper or lower thoracic spine instead of claiming to be in an exact interspace.

Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications

Epidural catheter placement offers flexibility in block management. However, during epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, and suboptimal catheter placement can affect the quality of anesthesia. We performed this prospective, randomized, double-blind study to assess the effect of a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle as a priming solution into the epidural space before catheter insertion. We randomized 240 patients into 2 equal groups and measured the quality of anesthesia and the incidence of complications. In the needle group (n = 100), catheters were inserted after injection of a full dose of local anesthetic through the needle. In the catheter group (n = 98), the catheters were inserted immediately after identification of the epidural space. Local anesthetic was then injected via the catheter. We noted the occurrence of paresthesia, inability to advance the catheter, or IV or subarachnoid catheter placement. Sensory and motor block were assessed 20 min after the injection of local anesthetic. Surgery was initiated when adequate sensory loss was confirmed. In the catheter group, the incidence of paresthesia during catheter placement was 31.6% compared with 11% in the needle group (P = 0.00038). IV catheterization occurred in 8.2% versus 2% of patients in the catheter and needle groups, respectively (P = 0.048). More patients in the needle group had excellent surgical conditions than the catheter group (89.6% versus 72.9; P < 0.003). We conclude that giving a single-injection dose via the epidural needle before catheter placement improves the quality of epidural anesthesia and reduces catheter-related complications.