Injection into the extra-arachnoid subdural space. Experience in the treatment of intractable cervical pain and in the conduct of extradural (epidural) analgesia

Epidural, Inadvertent Subdural, and Combined Epidural-Subdural Anesthesia in Lumbar Spine Surgery: A Retrospective Analysis

This study aimed to categorize contrast media images associated with epidural, subdural, and combined epidural-subdural anesthesia in patients who had undergone fluoroscopy-guided epidural anesthesia using contrast media combined with monitored anesthesia care (MAC) targeted at deep sedation, incorporating capnography over 5 years. Additionally, a correlation was established between the anesthetic effects and radiographic findings according to the categorized imaging appearances. This study included 628 patients who underwent endoscopic, open, or fusion surgery under epidural anesthesia at Nanoori Hospital in Gangnam between March 2018 and September 2023. Fluoroscopy-guided epidural anesthesia using contrast media combined with MAC and capnography was used. The dataset included detailed radiographic imaging, nursing, and anesthesia records. Distinct patterns of anesthesia administration were observed, with 49%, 19.6%, and 31% of patients receiving epidural, subdural, and combined epidural-subdural anesthesia, respectively. The incidence and duration of motor block were significantly different among the three groups. Additionally, subdural anesthesia displayed a higher incidence of motor block and a prolonged motor deficit duration than epidural anesthesia. Fluoroscopic guidance using a contrast medium for epidural and subdural anesthesia ensures precise space identification and prevents serious anesthetic complications. Our findings suggest the potential to achieve stable anesthesia, particularly using subdural and combined epidural-subdural anesthesia.

Inadvertent Subdural Catheter Placement: A Rare Complication in Obstetric Anesthesia

Epidural neuraxial analgesia is a standard procedure for pain control during labor and delivery. One rare complication is accidental epidural catheter placement in the subdural space, a potential space between the arachnoid and dura membranes.

The incidence of the subdural blockade during neuraxial block is unknown. The subdural block suspicion arises when the clinical signs and symptoms do not fit epidural or subarachnoid local anesthetic injection. The clinical picture includes delayed or gradual onset, extensive sensory block with minimal motor block, hypotension more than an epidural neuraxial block, and less than spinal neuraxial block, and it can rarely track intracranially and causes dyspnea and loss of consciousness.

In this article, we report a case of inadvertent subdural catheter placement that was diagnosed clinically with unexpectedly high block involving the upper extremities. No radiological confirmation was used for the diagnosis.

Pneumocephalus during cervical transforaminal epidural steroid injections: a case report

A cervical transforaminal epidural injection of anesthetic and corticosteroids (CTFESI) is a frequently used procedure for cervical radiculopathy. Most cases of pneumocephalus after an epidural block occur when using an interlaminar approach with the loss-of-resistance technique. The authors present the first case of pneumocephalus after cervical transforaminal epidural injection of anesthetic and corticosteroids. A 64-yr-old woman with left C7 radiculopathy was undergoing C6-7 transforaminal epidural injection of anesthetic and corticosteroids. The epidural spread of contrast was checked by fluoroscope, and 5 mg of dexamethasone in 4 ml of 0.1875% ropivacaine was injected. She lost consciousness 5 mins after the procedure and regained awareness after manual ventilation. She subsequently complained of nausea and headache, and a computed tomography brain scan revealed pneumocephalus. After carefully assessing the fluoroscopic images, the authors believe that the needle may have punctured the dura mater of the nerve root sleeve, allowing air to enter the subdural space. Thus, fluoroscopic images should be carefully examined to reduce dural puncture when performing cervical transforaminal epidural injection of anesthetic and corticosteroids, and air should be completely removed from the needle, extension tube, and syringe.

Subdural Block and the Anaesthetist

There are a number of case reports describing accidental subdural block during the performance of subarachnoid or epidural anaesthesia. However, it appears that subdural drug deposition remains a poorly understood complication of neuraxial anaesthesia. The clinical presentation may often be attributed to other causes. Subdural injection of local anaesthetic can present as high sensory block, sometimes even involving the cranial nerves due to extension of the subdural space into the cranium. The block is disproportionate to the amount of drug injected, often with sparing of sympathetic and motor fibres. On the other hand, the subdural deposition can also lead to failure of the intended block. The variable presentation can be explained by the anatomy of this space. High suspicion in the presence of predisposing factors and early detection could prevent further complications. This review aims at increasing awareness amongst anaesthetists about inadvertent subdural block. It reviews the relevant anatomy, incidence, predisposing factors, presentation, diagnosis and management of unintentional subdural block during the performance of neuraxial anaesthesia.

Unilateral Horner's syndrome and brachial plexus anesthesia during lumbar epidural blockade

Horner's syndrome is a rare side effect of epidural analgesia. In association with ipsilateral brachial plexus block, it has only been reported once before, in French. Unilateral blockade has also been reported, although its etiology is unclear and may be multifactorial. The patient described here experienced an asymmetrical epidural blockade with a unilateral Horner's syndrome and ipsilateral brachial plexus block.

Subdural block complicating spinal anesthesia?

IMPLICATIONS

Features suggestive of subdural block appeared after an apparently normal subarachnoid block. The long bevel of the reusable Quincke-type spinal needle may have contributed to the development of this complication. We propose that spinal needles should have a smaller bevel to minimize the possibility of such a complication.

A survey of epidural technique and accidental dural puncture rates among obstetric anaesthetists

Five hundred UK obstetric anaesthetists were surveyed to investigate retrospectively the relationship between experience, rotation of the epidural needle within the epidural space, choice of loss-of-resistance agent and accidental dural puncture (ADP) rate. Responses were received from 390 (78%) of the members surveyed. Anaesthetists with more than 15 years' experience are more likely to perform an epidural with the patient in the lateral position (P < 0.001), use loss-of-resistance to air to detect the epidural space (P < 0.001) and rotate the epidural needle after identifying the epidural space (P = 0.001) when compared to those of less experience. A reduced inadvertent dural puncture rate was found to be associated with increased frequency of performing the procedure (P = 0.012), greater experience of the practitioner (P = 0.049) and non-rotation of the epidural needle (P = 0.023). There are three components that can alter from case to case; patient positioning, loss-of-resistance agent and needle rotation. Loss-of-resistance agent and patient positioning in isolation did not significantly influence ADP rate. This study suggests that the combination of practising lateral patient positioning, loss-of-resistance to saline and non-rotation of the epidural needle significantly reduces ADP rate (P = 0.035).

Acute cauda equina syndrome after total knee arthroplasty as a result of epidural anesthesia and spinal stenosis

An unusual complication of epidural anesthesia performed for routine total knee arthroplasty is presented. Epidural catheter placement or removal resulted in an acute cauda equina syndrome in a patient with asymptomatic high-grade lumbar spinal stenosis at L3-4. The case is presented along with a literature review.

Unintentional paediatric subdural catheter with oculomotor and abducens nerve palsies

A 13-year-old female with a past history of lumbar laminectomy developed a subdural block 18 h after the commencement of an epidural infusion of bupivacaine 0.125% and fentanyl 2 micrograms.ml-1. Signs at presentation included bilateral abducens nerve palsies in the absence of headache and a previously unreported unilateral third cranial nerve palsy. An epidurogram displayed subdural placement.

Subdural cannulation and local anesthetic injection as a complication of an intended epidural anesthetic

We report a 52-year-old woman scheduled for laparotomy with combined epidural-general anesthesia who experienced abnormal responses to local anesthetic injections administered via the epidural catheter. The catheter subsequently was found to be in the subdural space. A review of the literature is provided.

Potential intrathecal leakage of solutions injected into the epidural space following combined spinal epidural anaesthesia

A combined spinal epidural anaesthetic (CSE), by design, produces a deliberate multicompartment block across a breached dural membrane. Since the lateral holes of the epidural catheter may lie in close proximity to the dural puncture site, a bolus solution of drug injected via the epidural catheter has the potential to leak through the dural puncture into the subarachnoid space. The aim of this study was to determine the incidence of intrathecal leak by performing an epidurogram. Fifteen patients undergoing surgery with a CSE anaesthetic using a 16 gauge Tuohy/26 gauge pencil point needle were studied. Within three hours of catheter insertion, 12 ml of contrast (iohexol 300 mg/ml) was injected via the epidural catheter under fluoroscopic control with screen recording and exposure of lateral and anteroposterior X-ray plates. All films were later reviewed for evidence of intrathecal spread. We did not observe any evidence of intrathecal spread of contrast. However, caution should be observed during administration of an intraoperative bolus dose of analgesic agent via a catheter inserted as part of a combined spinal epidural anaesthetic technique, particularly with the use of hydrophilic opiods.

An unusual complication following combined spinal-epidural anaesthesia for caesarean section

The combined spinal-epidural technique is widely used in obstetric anaesthetic practice. Epidural catheter migration through a dural hole is a theoretical but rarely described complication. We report a case of acute and life-threatening respiratory depression following administration of diamorphine through an epidural catheter after a single space combined spinal-epidural technique for caesarean section. We believe this complication occurred as a result of catheter migration through a dural hole into the subdural space and rupture of the thin arachnoid layer causing massive subarachnoid blockade.

Surgical anaesthesia for Caesarean section with a subdural catheter

PURPOSE

This case report describes a radiologically proven subdural catheter placed in a term parturient, which consistently performed as an epidural catheter for both labour analgesia as well as surgical anaesthesia.

CLINICAL FEATURES

The patient was a 26-yr-old, 52.7 kg. 140 cm healthy woman with a 39 wk intrauterine pregnancy. At initiation of epidural blockade, and for many hours throughout labour, an appropriate volume and concentration of local anaesthetic achieved an appropriate analgesic sensory level (10 ml bupivacaine 0.25%, bilateral T10 sensory level). However, for Caesarean section, while an appropriate volume and concentration of local anaesthetic achieved an appropriate surgical anaesthetic sensory level (15 ml bupivacaine 0.5%, bilateral T4 sensory level), there was no demonstrable motor blockade (0 on the Bromage scale). The Caesarean section was performed without incident, and without the need for supplemental intravenous opioids or anxiolytics.

CONCLUSION

We report the case to question the commonly held beliefs of subdural catheter presentation. We questioned the catheter position, and proved its subdural placement, only after larger volumes of higher concentration local anaesthetic did not achieve expected goals. It is possible that a high percentage of epidural catheters may be subdural, unbeknownst to the practitioner.

Subdural or epidural? Confirmation with magnetic resonance imaging

An epidural performed for obstetric analgesia was initially characteristic of a subdural block but subsequently behaved as a normal epidural. Radiological confirmation of the catheter having been subdural was established by performing a magnetic resonance imaging scan.

"Don't turn the needle!"

Accidental dural puncture is a well-recognised complication of epidural anaesthesia. The technique of inserting the epidural needle with the bevel parallel to the spinal ligaments is still taught in some centres. Evidence is presented that the subsequent turning of the needle to allow passage of the epidural catheter may increase the likelihood of dural puncture. There would also appear to be a greater chance of subdural catheterisation. The epidural needle should be introduced with the bevel in the direction in which the catheter is to go and not moved once the epidural space is located.

Development of a subdural motor blockade

We report an unusual development of motor blockade following the subdural injection of local anaesthetic during attempted continuous lumbar epidural anaesthesia. Four characteristic features of subdural block, extensive spread, segmental distribution, delayed onset, and short duration of motor blockade were all features of the case. The patient had gradual development of complete motor blockade in the left upper extremity, incomplete in the right upper extremity, but absence of motor blockade in the lower extremities. The duration of complete motor blockade was 10 min in the hand and 35 min in the arm. The spread of contrast medium in the subdural space revealed the extent and degree of motor blockade.

Possible inadvertent subdural block following attempted stellate ganglion blockade

A case is reported of suspected inadvertent subdural block following attempted stellate ganglion blockade for relief of cervicobrachial pain in a patient suffering from reflex sympathetic dystrophy. Possible complications due to neuraxial spread of local anaesthetics while performing a cervicothoracic ganglion blockade are considered.

Cervical epidural anaesthesia for carotid artery surgery

A series of 394 patients (251 men, 143 women; mean age 70.0 +/- 8.4 yr) selected for carotid artery surgery (CAS) performed under cervical epidural anaesthesia (CEA) was analysed retrospectively. Carotid endarterectomy was performed in 326 patients and saphenous vein bypass in 68. The cervical epidural administration of 15 ml 0.5 per cent bupivacaine or 0.37-0.40 per cent bupivacaine plus fentanyl (50-100 micrograms) resulted in an effective sensory blockade from C2 to T4-T8. Patients were maintained awake during the surgical procedure in comfortable condition. Serious complications included dural puncture in two patients, epidural venipuncture in six patients and respiratory muscle paralysis in three patients. Hypotension (10.9 per cent) and bradycardia (2.8 per cent) were the most frequent side-effects of CEA. Transient neurological events were noticed in 84 patients during the surgical procedure. A definite neurological deficit occurred postoperatively in 12 patients. Three patients suffered postoperative myocardial infarction. The mortality rate was 2.3 per cent (nine patients). Carotid artery surgery may be performed under CEA but haemodynamic variables should be monitored closely and managed closely during the procedure.

[Accidental catheterization of the subdural space: a complication of continuous spinal anesthesia and continuous peridural anesthesia]

Two cases of subdural catheter placement following continuous spinal and continuous epidural anaesthesia are presented. In the first, despite an easy reflux of clear cerebrospinal fluid through the catheter, the injection of 4 ml bupivacaine 0.5 per cent with epinephrine 1:200,000 followed by 3 ml tetracaine 0.5 per cent showed a failure of spinal anesthesia. In the second, the administration through the catheter of 20 ml lidocaine 2.0 per cent CO2 plus epinephrine 1:200,000 and of ten ml bupivacaine 0.5 per cent lead to an insufficient, patchy and asymmetrical analgesia. The clinical signs observed in these two cases are compared with previous publications. The importance of an x-ray contrast study to confirm the diagnosis of subdural catheter insertion is stressed.

Failure of a lidocaine test dose to identify subdural placement of an epidural catheter

We report the failure of a test dose of 3 ml lidocaine 1.5 per cent with 15 micrograms epinephrine to identify subdural placement of an epidural catheter in a parturient. Thirty-five minutes after injection of 13 ml lidocaine 1.5 per cent, intended to provide epidural analgesia, the patient developed an extensive sensory neural blockade. Some motor control was maintained and sympathetic block was incomplete. Blood pressure and oxygenation were easily supported with optimum positioning, fluids, ephedrine and oxygen by mask. The patient remained alert. The duration of neural blockade was approximately two hours. The patient underwent a second epidural for labour analgesia that was uneventful. There were no sequelae. Subdural injections are uncommon and unpredictable in their occurrence. Test doses do not consistently identify misplaced catheters. A negative response to a test dose does not guarantee that extensive neural blockade will not occur during epidural analgesia.

Subarachnoid spread of epidural local anaesthetic following dural puncture

A case is described of an extensive block and hypotension which occurred after inadvertent dural puncture and subsequent epidural injection of bupivacaine. The subarachnoid spread of solution from the extradural space was confirmed radiologically.

Extradural block. Confirmation of the injection site by X-ray monitoring

X-ray monitoring was used to confirm the accuracy of extradural block in 100 patients who attended the Pain Relief Clinic for treatment of a variety of different conditions. A Tuohy needle was introduced by the central or paramedian approach and conventional physical signs, notably loss of resistance, used to identify entry into the extradural space. A radio-opaque dye was introduced prior to the analgesic solution, to display the injection site. X-ray screening confirmed the accuracy of the block in 83 patients, but unexpectedly in 17 the point of the needle was either just outside the spinal canal or only partly in the extradural space. There was no difficulty in correcting the needle position with the X-ray facilities available. Imprecise needle siting is only partially explained by technical problems. Imprecise siting of the needle may be responsible for at least some cases of inadequate analgesia or unexpected complications. In our view X-ray confirmation of site is essential for difficult extradural blocks, or when neurolytic solutions are introduced into the spinal canal. It may also be useful in teaching and research.

A rare complication of extradural analgesia

A case is reported of probable subdural injection of bupivacaine during attempted extradural analgesia for an operative obstetric procedure.

Extensive spread of local anaesthetic solution following subdural insertion of an epidural catheter during labour

A case is described where a small dose of bupivacaine was accidentally injected into the subdural, extra-arachnoid space resulting in extensive unilateral block and hypotension. The spread of solution was confirmed radiologically.

An extensive lumbar epidural block

Following lumbar epidural anaesthetic a 17-year-old primigravida developed a sensory block extending to C6 and a motor block affecting her legs, arms and intercostal muscles. The progression of clinical events suggests a subdural injection of bupivacaine.

Epidural anaesthesia with chloroprocaine. Delayed onset, extensive spread, and prolonged duration

A case report of continuous lumbar epidural anaesthesia with chloroprocaine is described in which delayed onset, extensive and delayed spread, and prolonged duration were observed. Although placement of neither the needle nor the catheter was confirmed radiographically, the anaesthetic course may be consistent with extra-arachnoid subdural injection of the local anaesthetic solution. Other reported cases, with similar features and which may be explained in the same way, are also discussed.

An epidural anaesthetic with unusual complications

Respiratory paralysis and prolonged duration of anaesthesia followed lumbar epidural block with bupivacaine. Subdural, extra arachnoid block is postulated.