Case Report Inadvertent Subdural Injection during Cervical … · 2020. 1. 27. · Rare major complications include direct spinal cord trauma, epidural hematoma or abscess, transection

Hindawi Publishing CorporationCase Reports in AnesthesiologyVolume 2013, Article ID 847085, 5 pageshttp://dx.doi.org/10.1155/2013/847085

Case ReportInadvertent Subdural Injection during CervicalTransforaminal Epidural Steroid Injection

Kesavan Sadacharam,1 Jeffrey D. Petersohn,2 and Michael S. Green1,3

1 Drexel University College of Medicine, Hahnemann University Hospital, Philadelphia, PA 19102, USA2Drexel University College of Medicine, Pain Care PC, Linwood, NJ 08221, USA3Department of Anesthesiology, New College Building, Room 7502, 245 North 15th Street, Mail Stop 310, Philadelphia, PA 19102, USA

Correspondence should be addressed to Michael S. Green; [email protected]

Received 23 October 2013; Accepted 17 December 2013

Academic Editors: G. Hans, Y.-C. Lee, P. Michalek, and E. A. Vandermeersch

Copyright © 2013 Kesavan Sadacharam et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properlycited.

Serious complications following cervical epidural steroid injection are rare. Subdural injection of local anesthetic and steroidrepresents a rare but potentially life threatening complication. A patient presented with left sided cervical pain radiating into the leftupper extremity with motor deficit. MRI showed absent lordosis with a broad left paramedian disc-osteophyte complex impingingthe spinal cord at C5-6. During C5-6 transforaminal epidural steroid injection contrast in AP fluoroscopic view demonstrated asubdural contrast pattern. The needle was withdrawn slightly and repositioned. Normal lateral epidural and nerve root contrastpattern was subsequently obtained and injection followed with immediate improvement in radicular symptoms. There were nopostoperative complications on subsequent clinic follow-up.The subdural space is a potential space between the arachnoid and duramater. As the subdural space is larger in the cervical region, there may be an elevated potential for inadvertent subdural injection.Needle placement in the cervical subdural space during transforaminal injection is uncommon. Failure to identify aberrant needleentry within the cervical subdural space may result in life threatening complications. We recommend initial injection of a limitedvolume of contrast agent to detect inadvertent subdural space placement.

1. Introduction

Cervical radiculopathy is a common condition affecting 83per 100,000 persons each year [1]. The cause varies by patientage with intervertebral disc herniation common in youngerpersons and spondylosis predominating in the older agegroup. Cervical spondylosis is present in 75% of patientsolder than 65 years of age. Both pathologies can produceanatomic stenosis resulting in impingement or compressionof nerve roots or spinal cord. Presenting symptoms includecervical pain with or without radiculopathic upper extremitypain, weakness, deep tendon reflex depression, headache, orvertigo. Duration and severity of symptoms directs selec-tion of treatment modality. Common conservative treatmentconsists of nonsteroidal anti-inflammatory drugs, anticon-vulsants, muscle relaxants, and physical therapy. Efficacy ofcervical epidural steroid injection for patients unresponsiveto conservative treatment has been demonstrated [2–4].

Symptoms refractory to interventional care or demonstratingmyelopathic symptoms of spinal cord compression necessi-tate consideration for surgical intervention.

Epidural injection in the cervical spine can be performedby interlaminar or transforaminal approaches. Transforam-inal injection provides the most direct route for delivery ofmedication to the lateral recess or foraminal pathology. Aslow resistance to liquid flow is expected in the dorsal epiduralspace compared with high flow resistance imposed by lateralrecess or foraminal narrowing, interlaminar approaches mayfail to deliver adequate medications to pathology located dis-tally in the anterolateral epidural space orwithin the radicularcanal. Potentially superior outcomes support use of thetransforaminal approach [4–7].

Derby et al. report the overall rate of complication follow-ing cervical epidural steroid injections as 5 per 1000 injections[8]. Complications described as minor include vasovagalepisodes, rashes, headache, worsening pain, new paresthesia,

2 Case Reports in Anesthesiology

and pain. Rare major complications include direct spinalcord trauma, epidural hematoma or abscess, transection ofvertebral artery, and injection of particulate steroid intoa radiculomedullary artery or vertebral artery resulting inspinal cord or posterior cerebellar embolic infarction [9, 10].Subdural injection of local anesthetic and steroid representsa rare but potentially life threatening complication. Theincidence of subdural injection is 0.8% with lumbar epiduralinjection [11] and surprisingly high 1.6–3.2% during diagnos-tic myelography [12]. We present a case where expeditiousrecognition of subdural space injection allowed adjustmentof technique and avoided a potentially deleterious patientoutcome.

2. Case Description

A 37-year-old, right-handed female presented with left sidedcervical pain radiating into the left upper extremity with ipsi-lateral fourth and fifth digit numbness and complaint of leftupper extremity weakness. Her pain followed amotor vehicleaccident one year prior to interventional pain consultation.Extensive unhelpful conservative treatments including phys-ical therapy, chiropractic care, and pharmacologic interven-tion preceded her visit. Examination showed painless cervicalflexion and extension to 50 and 40 degrees, respectively. Leftsided cervical pain occurred with lateral cervical rotation toboth the left and right. Anterior foraminal tenderness wasnoted at left C6 and C7 nerve levels with positive Tinel’sphenomenon radiating pain into the extremity. Hypoesthesiawas noted in left C6 and C7 dermatomes with decreasedmotor power on left elbow extension, flexion, and forearmpronation.Deep tendon reflexeswere intact and symmetrical.Radiographs demonstrated anterior osteophytes at C5-C6-C7. Cervical spine MRI showed absent lordosis with abroad left paramedian disc-osteophyte complex impingingthe spinal cord at C5-6 andmild right C5-C6 neuroforaminalstenosis.There were chronic degenerative disc changes at C5-C6 and C6-C7. A left C5-6 transforaminal epidural steroidinjectionwas planned in amonitored operating room setting.

The patient was placed in “park bench” position andfollowing propofol based monitored anesthesia care, the leftC5-6 neural foramen was visualized with anterior obliquefluoroscopic view and a 25 gauge 2.5 inch short bevel needlewas advanced to enter themidneural foramen at the posteriorborder. Anterior posterior (AP) fluoroscopic views facilitatedadvancement of the needle tip to beneath the midpoint ofthe pedicle. Following negative aspiration of blood or CSF,injection of iohexol radiocontrast 0.3mL demonstrated abroad homogenous density extending over about 1/3 of theipsilateral vertebral canal in AP view (Figure 1). Oblique flu-oroscopic view unexpectedly demonstrated extensive linearopacification along the posterior border of the epidural spacefrom C5 to T1 (Figure 2). Inadvertent subdural injection wasdiagnosed. The needle was withdrawn slightly and reposi-tioned with subsequent contrast injection demonstrating asatisfactory neurogram of the proximal nerve root and dorsalroot ganglion with contrast entry in the lateral epidural space(Figures 3 and 4). Injection of bupivacaine 0.25% 0.5mLand betamethasone 3mg followed. Her radicular symptoms

Figure 1: Anterior Posterior radiograph of the cervical spineshowing subdural spread of dense contrast media. Multiple blackarrows illustrate unusual contrast spread towards the midline.

Figure 2: Oblique view of cervical spine with homogenous, highdensity, and elongated contrast outline limited to the dorsal aspectof the spinal canal indicating subdural spread. Arrow show themaximal extent of the unusual extensive cephalocaudal spread ofcontrast media with a sharp posterior border and a slightly wavyanterior border.

were improved when evaluated 15 minutes thereafter in thepostanesthesia care unit. No immediate postoperative com-plaints of pain or headache existed. Office follow-up demon-strated an entirely uncomplicated course with completeresolution of cervical pain and radicular symptoms.

3. Discussion

The spinal cord and the spinal nerve proximal to the dorsalroot ganglion are surrounded by a trilaminar structure com-posed of an outer layer of dense fibrous dura mater, a middlearachnoid layer of thin nonvascular tissue, and inner pial

Case Reports in Anesthesiology 3

Figure 3: Repeat contrast injection following needle repositioningshows epidural injection with clear outline of nerve root, dorsalroot ganglion, and lateral epidural space as demonstrated by arrow.Additional contrast is retained in the vertebral canal.

Figure 4: Oblique view after needle repositioning and repeatcontrast injection shows the typical contrast pattern for epiduralinjection with limited cephalocaudal spread and outlining of nerveroots superimposed upon the extensive prior subdural contrastspread (seen here as caudally as T2).

layer of thick vascular connective tissue. The dura-arachnoidinterface is formed by the outer layer of the arachnoidmembrane and inner layer of dura mater. The outer surfaceof the arachnoid mater consists of closely arranged cells withnumerous tight junctions with minimal extracellular space.The compact and tightly arranged nature of the cells providesthe effective barrier between cerebrospinal fluid and bloodcirculation in dura mater. In contrast, the inner layer of duramater is characterized by cells with few cellular junctions,no extracellular collagen, and multiple enlarged extracellularspaces. Electronmicroscopy shows the dura-arachnoid inter-face to be filled with neuroepithelial cells interconnected byfew intercellular junctions. The presence of neuroepithelialcells within the dura-arachnoid interface demonstrates that

this is not a true potential space like the intrapleural space[12]. Vandenabeele et al. [11] used electron microscopy toshow a natural close connection between the outer layer ofarachnoid membrane and inner layer of dura mater, but thecombination of loosely arranged cells of the inner surface ofthe dura mater, absence of collagen, and few intercellularjunctions among neuroepithelial cells provides the potentialfor a cleavage plane with subsequent enlargement of the sub-dural space due to pressure or trauma from air or fluid injec-tion [11, 12]. While the dura mater and arachnoid can beseparated by gently rolling the tissue between the fingers, it isunknown whether separation of these layers, and henceenlargement of the subdural space, occurs more frequentlyin patients with a history of trauma.

As the subdural space is larger in the cervical regionas compared to the lumbar region, the risk for inadvertentsubdural injections may also be greater in the cervical region.The subdural space typically extends from the inferior borderof the second sacral vertebra into the intracranial space unlikethe epidural space which typically terminates at the foramenmagnum. As the subdural space is widest in its lateral anddorsal aspects, liquid injected into the subdural space willfill the dorsal and lateral compartments first. Since the dorsalspinal cord structures are predominantly composed of sen-sory fibers as opposed to the anterior cord structures whichcontain motor and sympathetic tracts, the clinical presenta-tion of subdural injection affecting the spinal cord tends toproduce predominant symptoms of sensory neural blockaderather than symptoms of either motor or sympathetic block[13, 14].

The greatest hazard of subdural injection may be posedby injection of local anesthetic into the subdural space as thesmall volume of the subdural space may allow material tobe injected transforaminally to reach intracranial structuresleading to significant neurological and hemodynamic com-plications including loss of consciousness, severe hypoten-sion, bradycardia, and cardiac arrest [15, 16]. While initialinjection of local anesthetics into the subdural spacemay pro-duce symptoms and signs similar to intrathecal injection,subtle differences are noted. Collier described four clinicalcriteria as diagnostic of subdural injection including moder-ate hypotension, slow onset of symptoms, progressive respir-atory difficulty, and complete recovery in 2 hours’ time [17].Hypotension and apnea are moderate as sympathetic andmotor fibers in the cervical spinal cord are less affected thanthe posterior sensory structures.

Cervical interlaminar epidural injections and transfora-minal approaches to the epidural space must be performedwith fluoroscopic guidance, in the author’s opinion. Imagingin at least two planes, typically AP and either an oblique orlateral plane, is required to confirm initial needle position.Confirmation of adequate needle placement by injection ofcontrast media requires observation of the pattern of contrastflow under continuous fluoroscopy or by digital subtractionangiography. With correct placement of needle at the neuralforamen, the nerve root and dorsal root ganglion should beoutlined by contrast in theAP fluoroscopic view. In the lateralview, there may be anterior as well as posterior dispersion ofcontrast into the epidural space. An oblique image may show

4 Case Reports in Anesthesiology

a ring of contrast surrounding the exiting nerve root. Thepotential for diagnostic ultrasound to demonstrate subduralinjection has been reported in dogs and horses [18].

In the case of inadvertent subdural space injection, theAP fluoroscopic view will show a dense collection of contrastextending in a homogenous fashion towards the center ofthe vertebral canal but typically without outline of the lateralepidural space, exiting nerve root or dorsal root ganglion.The lateral fluoroscopic viewwill demonstrate a homogenous,high density, elongated contrast outline typically limited tothe dorsal aspect of the spinal canal. Due to the smallvolume of the subdural space relative to the epidural space,the cephalocaudal contrast spread will extend over multiplevertebral segments, as opposed to the typical single levelcontrast dispersion seen with injection of the same volumeinto the epidural space. Practitioners should become awareof the expectable limited cephalocaudal extent of normalcontrast flow when using small volumes (0.3–0.5mL) ofinjected contrast. While the posterior outline of the injectedsubdural contrast may be linear due to the dura mater, theanterior border, if opacified by contrast, may appear irregulardue to the arachnoid mater [19, 20]. Given identical volumesof contrast injection, the density of the subdural contrast willbe far greater due to dilution of intrathecal contrast by CSF[19].While the pattern of subarachnoid contrast changes withalteration in body position to reflect gravity, such migrationis theoretically less likely with subdural injection.

Needle placement in the cervical subdural space duringtransforaminal injection is an uncommon event. Failure toidentify aberrant needle placement by observation of theextent and nature of the radiocontrast dispersion may resultin life threatening complications upon subsequent injectionof steroid and local anesthetic into the subdural space. Inter-ventional pain physicians must have an adequate knowledgeof normal and abnormal patterns of epidural and perineuralcontrast dispersion and flow in order to avoid harm topatients. This complication probably occurs more often thanis recognized and may lead not only to a lack of efficacy, butalso to a potential hazard [21]. Thus, we recommendthat physicians performing transforaminal cervical epiduralinjection routinely initially inject a limited contrast volume(0.3mL) under continuous fluoroscopy with diligent assess-ment of biplanar contrast spread as a viable strategy to detectsubdural injection.

References

[1] C. W. Huston, “Cervical epidural steroid injections in the man-agement of cervical radiculitis: interlaminar versus transforam-inal. A review,” Current Reviews in Musculoskeletal Medicine,vol. 2, no. 1, pp. 30–42, 2009.

[2] K. Bush and S. Hillier, “Outcome of cervical radiculopathytreated with periradicular/epidural corticosteroid injections: aprospective study with independent clinical review,” EuropeanSpine Journal, vol. 5, no. 5, pp. 319–325, 1996.

[3] K. Strobel, C. W. A. Pfirrmann, M. Schmid, J. Hodler, N. Boos,and M. Zanetti, “Cervical nerve root blocks: indications androle of MR imaging,” Radiology, vol. 233, no. 1, pp. 87–92, 2004.

[4] C. M. Bono, G. Ghiselli, T. J. Gilbert et al., “An evidence-basedclinical guideline for the diagnosis and treatment of cervicalradiculopathy from degenerative disorders,” Spine Journal, vol.11, no. 1, pp. 64–72, 2011.

[5] M. K. Schaufele, L. Hatch, and W. Jones, “Interlaminar versustransforaminal epidural injections for the treatment of symp-tomatic lumbar intervertebral disc herniations,” Pain Physician,vol. 9, no. 4, pp. 361–366, 2006.

[6] E. Thomas, C. Cyteval, L. Abiad, M. C. Picot, P. Taourel, andF. Blotman, “Efficacy of transforaminal versus interspinouscorticosteroid injection in discal radiculalgia—a prospective,randomised, double-blind study,” Clinical Rheumatology, vol.22, no. 4-5, pp. 299–304, 2003.

[7] O. Berger, V. Dousset, O. Delmer, V. Pointillart, J. M. Vital, andJ. M. Caillé, “Evaluation of CT-guided periganglionic foraminalsteroid injections for treatment of radicular pain in patientswith foraminal stenosis,” Journal de Radiologie, vol. 80, no. 9,pp. 917–925, 1999.

[8] R. Derby, S. Lee, B. Kim, Y. Chen, and K. S. Seo, “Complicationsfollowing cervical epidural steroid injections by expert inter-ventionalists in 2003,” Pain Physician, vol. 7, no. 4, pp. 445–449,2004.

[9] R. Baker, P. Dreyfuss, S. Mercer, and N. Bogduk, “Cervicaltransforaminal injection of corticosteroids into a radicularartery: a possible mechanism for spinal cord injury,” Pain, vol.103, no. 1-2, pp. 211–215, 2003.

[10] P. J. A. M. Brouwers, E. J. B. L. Kottink, M. A. M. Simon, andR. L. Prevo, “A cervical anterior spinal artery syndrome afterdiagnostic blockade of the right C6-nerve root,” Pain, vol. 91,no. 3, pp. 397–399, 2001.

[11] F. Vandenabeele, J. Creemers, and I. Lambrichts, “Ultrastruc-ture of the human spinal arachnoid mater and dura mater,”Journal of Anatomy, vol. 189, no. 2, pp. 417–430, 1996.

[12] M. A. Reina, O. D. L. Casacola, A. Lopez, J. A. D. Andres, M.Mora, and A. Fernandez, “The origin of the spinal subduralspace: ultrastructure findings,” Anesthesia and Analgesia, vol.94, no. 4, pp. 991–995, 2002.

[13] S. Bansal andM. J. Turtle, “Inadvertent subdural spread compli-cating cervical epidural steroid injection with local anaestheticagent,” Anaesthesia and Intensive Care, vol. 31, no. 5, pp. 570–572, 2003.

[14] A. H. Ajar, J. P. Rathmell, and S. K. Mukherji, “The subduralcompartment,” Regional Anesthesia and Pain Medicine, vol. 27,no. 1, pp. 72–76, 2002.

[15] L. J. Lehmann and V. S. Pallares, “Subdural injection of a localanesthetic with steroids: complication of epidural anesthesia,”Southern Medical Journal, vol. 88, no. 4, pp. 467–469, 1995.

[16] D. Agarwal, M. Mohta, A. Tyagi, and A. K. Sethi, “Subduralblock and the anaesthetist,” Anaesthesia and Intensive Care, vol.38, no. 1, pp. 20–26, 2010.

[17] C.Collier, “Total spinal ormassive subdural block?”Anaesthesiaand Intensive Care, vol. 10, no. 1, pp. 92–93, 1982.

[18] P. V. Scrivani, P. Y. Barthez, R. Léveillé, S. C. Schrader, and S. M.Reed, “Subdural injection of contrast medium during cervicalmyelography,”Veterinary Radiology and Ultrasound, vol. 38, no.4, pp. 267–271, 1997.

[19] W. P. Milants, P. M. Parizel, J. de Moor, I. G. Tobback, and A. M.de Schepper, “Epidural and subdural contrast in myelographyand CT myelography,” European Journal of Radiology, vol. 16,no. 2, pp. 147–150, 1993.

Case Reports in Anesthesiology 5

[20] J. Penderis, M. Sullivan, T. Schwarz, and I. R. Griffiths, “Sub-dural injection of contrast medium as a complication of myel-ography,” Journal of Small Animal Practice, vol. 40, no. 4, pp.173–176, 1999.

[21] G. Malhotra, A. Abbasi, and M. Rhee, “Complications of trans-foraminal cervical epidural steroid injections,” Spine, vol. 34, no.7, pp. 731–739, 2009.

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Case Report Inadvertent Subdural Injection during Cervical … · 2020. 1. 27. · Rare major complications include direct spinal cord trauma, epidural hematoma or abscess, transection