We report two detrimental neurologic complications after technically correct selected cervical nerve root blocks. Based on these cases and a thorough review of the literature, the indication for cervical nerve root blocks was reconsidered and limited. Similarly, we modified our technique to further reduce the likelihood for the occurrence of such severe complication

Boos, Norbert

Hodler, Juerg

Schubert, Martin

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CASE REPORTMust we discontinue selective cervical nerve root blocks?Report of two cases and review of the literatureJuerg Hodler • Norbert Boos • Martin SchubertReceived: 10 December 2011 / Revised: 21 August 2012 / Accepted: 18 December 2012 / Published online: 18 January 2013 Springer-Verlag Berlin Heidelberg 2013Abstract We report two detrimental neurologic compli-cations after technically correct selected cervical nerve rootblocks. Based on these cases and a thorough review of theliterature, the indication for cervical nerve root blocks wasreconsidered and limited. Similarly, we modified ourtechnique to further reduce the likelihood for the occur-rence of such severe complications.Keywords Cervical nerve root  Block  Injection Safety  Technique  Corticosteroids  ComplicationsIntroductionThe rationale for selective nerve root blocks is to tackle theinflammatory component of a nerve root compromise causedby a herniated disk or an osseous foraminal stenosis. There-fore, the goal is not to cure the patient by interfering withunderlying pathogenetic factors, i.e., mechanical compressionresponsible for the radiculopathy but rather to provide tem-porary relief from peak pain during the time required forspontaneous resolution of radiculopathy [10, 11, 15].There are only a few studies regarding selective cervicalnerve root blocks [10, 11]. Strobel et al. [19] reported on 60patients with cervical radiculopathy. The authors investi-gated whether magnetic resonance imaging findings canpredict pain relief after CT-guided cervical root nerveblock. The mean percentage of pain reduction (VAS) was46 %. Patients with foraminal disk herniation, foraminalnerve root compromise, and no spinal canal stenosis appearto have the best pain relief after this procedure. Bergeret al. [2] reported effective long-term pain relief in 11 of 18patients with cervical radiculopathy (61 %) undergoingCT-guided foraminal injections. Slipman et al. [18] retro-spectively investigated fluoroscopically guided cervicalnerve root block in 20 patients with cervical spondyloticradicular pain. In 60 % of the patients, an overall good orexcellent result was observed. Vallee et al. [21] treated 32patients with chronic cervical radiculopathy unresponsiveto medical treatment alone by periradicular corticosteroidinjections. The mean evolutionary trends for radicular andneck pain relief were significant at 14 days (P \ 0.001)and at 6 months (P \ 0.001). The procedure did not pro-duce any complications. In a large series of 802 proceduresusing an anterior oblique approach, Phobiel et al. [14] didnot encounter any major complications.Complications subsequent to cervical nerve root blocksremain very rare but may be more common than generallyanticipated [17]. This particularly includes detrimentalcomplications of the basilary arterial territory such ascerebellar and spinal cord infarction [16, 20]. Most often,such complications appear to be associated with the dis-section or intra-arterial injection of crystalline steroids ofJ. HodlerDepartment of Radiology, Orthopedic University HospitalBalgrist, University of Zurich, Zurich, SwitzerlandJ. HodlerInstitute of Diagnostic and Interventional Radiology,University Hosptial Zurich, University of Zurich,Ra¨mistrasse 100, 8091 Zurich, Switzerlande-mail: juerg.hodler@usz.chN. Boos (&)Department of Spine Surgery, Orthopedic University HospitalBalgrist, University of Zurich, Zurich, Switzerlande-mail: norbert.boos@prodorso.chM. SchubertSpinal Cord Injury Centre, University Hospital Balgrist,University of Zurich, Zurich, Switzerlande-mail: martin.schubert@balgrist.ch123Eur Spine J (2013) 22 (Suppl 3):S466–S470DOI 10.1007/s00586-012-2642-zthe vertebral artery [17]. Such complications should beavoidable using image guidance correctly, both fluoros-copy and CT. However, there appears to be the possibilityof infarction resulting from impaired perfusion of the majorfeeding anterior radicular artery of the spinal cord [4]. Suchsmall vessels [8] may not be seen during image-guidedinjection, whatever imaging method is employed. Thismakes it practically impossible to avoid such complications.The objective of this case report is to communicatedetrimental complications after technically correct nerveroot blocks in two patients resulting in incomplete transienttetraparesis as well as to discuss the procedural conse-quences implemented in our institution.Case studiesCase 1The first patient was a 71-year-old woman who developeda tetraplegia subsequent to a cervical nerve root block andwas referred to our spinal cord injury unit. A radiologistwith an experience of approximately 1,000 cervical nerveroot injections had performed a C7/T1 foraminal injectionon the left side, based on the presence of a foraminal ste-nosis. The needle was placed outside the intervertebralforamen to diminish the risk of an intravascular injection(Fig. 1a). A tentative injection of contrast media demon-strated extraforaminal contrast distribution. The reportindicates that ‘‘diluted’’ Iotralan (Isovist, Bayer-ScheringPharma, Berlin, Germany) was used. The following injec-tion using triamcinolon (40 mg, 1 ml Kenacort 40, Der-mapharm, Huenenberg, Switzerland) and—according tothe report—a ‘‘small’’ amount of local anesthetics (Bupi-vacain, Carbostesin, AstraZeneca, Zug, Switzerland) ledto immediate and excruciating pain and tetraplegia. An MRof the cervical spine performed on the day after injectiondemonstrated ischemic myelopathy at the C5–C7 levels(Fig. 1b). The patient initially had a complete tetraplegiabelow the C5 level, AIS A which recovered to AIS D [12]during the following 8 months of rehabilitation. In spite ofthe improvements during rehabilitation, the patientremained wheelchair-bound.Case 2The second patient was a 59-year-old man with chronicradicular C6 and C7 right-sided pain in the presence ofcervical spine degeneration. Periradicular injection of boththe C6 and C7 nerve root were requested by the referringphysician. For both injections, 23 gauge (0.6 mm), 6-cmlong needles were used according to the institution’sstandard protocol. The needles were advanced step-by-step,while injecting small amounts of ropicvacain (Naropin,0.2 %, AstraZeneca, Zug, Switzerland). The C6 injectionwas performed first and was uneventful. For the C7injection, the needle tip was placed at the entrance of theC6/7 foramen dorsally. 0.5 ml of contrast agent wasinjected after needle placement under fluoroscopic control(Iopamidol, Iopamiro 200, Bracco, Milan, Italy). Contrastdistribution was in the posterior part of the foramen(Fig. 2a). 20 mg (0.5 ml) of triamcinolon (Kenacort 40,Dermapharm, Huenenberg, Switzerland) and 1 ml of Nar-opin 0.2 % (Ropivacain, AstraZeneca, Zug, Switzerland)were then injected. Nearly immediately, the patient com-plained about visual color misperception and severeshoulder pain and became tetraplegic with incompletesensory-motor deficits below the C4 level, AIS C [12]within minutes. MR images obtained 1 day after injectiondemonstrated spinal cord signal abnormalities consistentwith ischemic myelopathy at the C4–C6 levels (Fig. 2b).Fig. 1 Imaging studies of a 71 year old female (Case 1). a C7/T1foraminal injection on the left side. Needle position outside theintervertebral foramen. A tentative injection of contrast mediademonstrated extraforaminal contrast distribution. b T2-weightedsagittal MR image obtained 1 day after injection demonstratingischemic myelopathy at the C5–C7 levelsEur Spine J (2013) 22 (Suppl 3):S466–S470 S467123The patient improved considerably and was dismissed after4 months of rehabilitation with incomplete tetraplegiabelow C4 (AIS D). He was ambulatory without aids.However, paresis accentuated at the hands persisted,consistent with a mild central cord syndrome.DiscussionIn the light of the aforementioned detrimental and unex-pected complications, a critical re-assessment of the indi-cation for selective cervical nerve root blocks is prompted.Approximately at the time of the second incident, anarticle was published by Scanlon et al. [17] highlightingcomplications of cervical nerve root injections. This cross-sectional survey described the occurence of 78 severeneurological side effects in the context of cervical trans-foraminal injections in the United States. An embolicmechanism was assumed for the majority of cases reportedby Scanlon et al. [17] and is likely to have caused the spinalinjury in our patients as well. An inadvertent intra-arterialinjection of particulate corticosteroid was reported to causea distal infarction [17]. The most common complicationwas infarction related to the vertebrobasilary territory(n = 16). Many complications, however, were notexplained by injection into the vertebral artery but ratherby injection of radicular arteries communicating with theanterior spinal artery and a network of medullary vessels[17]. There are few articles describing the relevant anat-omy [8]. These radicular arteries are small, variable innumber and location and may not be detected duringimage-guided contrast injections. Based on this descrip-tion, there is no safe way to avoid these vessels by using acertain needle position or type [5]. To observe bloodflowing back into the syringe before injection and then toreposition the needle may not be more useful becausesensitivity of backflow of blood for intra-arterial needleposition is only 45.9 % [6]. Imaging may detect inadver-tent intravascular injections. CT precisely demonstrates theneedle tip in relation to the vertebral artery [22], but maynot detect very small vessels and vessels running out of theimaging plane [3]. CT has not been proved to be less safethan fluoroscopy guidance. In the article by Scanlon et al.[17], 59 of the 78 injections were performed by anesthe-siologists, 13 by physiatrists, two by orthopedic surgeons,and one each by a radiologist, a neurologist and familymedicine physician. It is fair to assume that most of theseinjections have been performed under fluoroscopic guid-ance and not with CT.There are many different types of fluoroscopic units.Although contrast within small vessels may indeed bebetter demonstrated by fluoroscopy this requires optimalequipment, possibly with subtraction imaging [3]. A testinjection of local anaesthetics has been recommended inorder to prevent intravascular injection of steroids [9]. Incase of intravascular injection, transient neurologicalsymptoms may occur which prevent the injection ofsteroids. Based on the current literature [1, 13], the useof non-particulate steroids is advocated when injectionsare made around the spinal cord including the conusbecause of the decreased risk of a neurologic complica-tion. According to a recent review, the study by Scanlonet al. shows the strongest association to date betweenparticulate corticosteroids and brain/spinal cord infarc-tions [1].In a pig model, injection of particulate steroids (meth-ylprednisolone) into the vertebral artery lead do death in4/4 animals while all non-particulate steroids (dexameth-asone, prednisolone) survived and did not demonstrategross abnormalities on MR images or histologically. Therehas been a debate regarding the use of blunt versus pointedFig. 2 Imaging studies of a 59 year old male (Case 2). a Needle tip atthe entrance of the right C6/7 foramen dorsally, after injection of0.5 ml of contrast agent. b Sagittal T2-weighted MR image obtained1 day after injection demonstrated spinal cord signal abnormalitiesconsistent with ischemic myelopathy at the levels C4–C6S468 Eur Spine J (2013) 22 (Suppl 3):S466–S470123needle tips but no obvious advantage of blunt needles hasbeen shown [7, 8].ConclusionsCervical nerve root blocks may more commonly causecomplications than anticipated by many physicians order-ing or performing nerve root blocks. The location of theinjection close to delicate central nervous structures andtheir ample vascular supply entails the possibility of severeneurological complications, one of the most likely beinginfarctions of the cervical cord and ischemia within theterritory of the vertebrobasilary system. Careful needlepositioning and documentation is required. Probatoryinjection of local anesthetics is recommended prior to theinjection of the therapeutic compound. Application ofnon-particulate steroids is recommended.Procedural modifications made in our centerBased on the aforementioned conclusions, we have dis-continued the use of pure diagnostic subaxial and thera-peutic atlanto-axial nerve root blocks because of theimmanent risks. However, we continue with the applicationof therapeutic subaxial selective cervical nerve root blocksif:• patients gave an informed consent after being informedthat there is a small (estimated 1:3,500) but unavoid-able risk of severe complications associated withcervical nerve root blocks including permanent neuro-logical damage• indication is unequivocal, i.e., radicular pain concor-dant with imaging findings and severe symptoms non-responsive to usual conservative treatment• a strictly posterior approach can be done with thepatient in the supine position. The needle tip is placedat the antero-lateral aspect of the facet joint. The needleis not further advanced into the course of the nerve rootin order to avoid any chance of injecting a radicularartery (Fig. 3)• probatory injection is possible with local anaesthetics.The patient is asked about any new symptoms beforesteroids injection after a waiting period of at least 2 min• non-particular (e.g., dexamethasone) steroids areinjected slowly.Conflict of interest None.References1. Benedetti EM, Siriwetchdarek R, Stanec J, Rosenquist R (2009)Epidural steroids injections: complications and management.Tech Reg Anesth 13:236–2502. Berger O, Dousset V, Delmer O, Pointillart V, Vital JM, CailleJM (1999) Evaluation of the efficacy of foraminal infusions ofcorticosteroids guided by computed tomography in the treatmentof radicular pain by foraminal injection. J Radiol 80:917–9253. Bogduk N, Dreyfuss P, Baker R, Yin W, Landers M, Hammer M,Aprill C (2008) Complications of spinal diagnostic and treatmentprocedures. Pain Med 9:S11–S344. 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Karasek M, Bogduk N (2004) Temporary neurologic deficit aftercervical transforaminal injection of local anaesthetic. Pain Med5:202–20510. Leonardi M, Pfirrmann CW (2008) Spinal injections. In: Aebi M,Boos N (eds) Spinal disorders. Fundamentals of diagnosis andtreatment. Springer, Heidelberg, pp 261–29011. Leonardi M, Pfirrmann CW, Boos N (2006) Injection studies inspinal disorders. Clin Orthop Relat Res 443:168–18212. Marino RJ, Barros T, Biering-Sorensen F, Burns SP, DonovanWH, Graves DE, Haak M, Hudson LM, Priebe MM (2003)International standards for neurological classification of spinalcord injury. J Spinal Cord Med 26(Suppl 1):S50–S56Fig. 3 The patient is positioned supine and the needle is advance tothe lateral and anterior aspect of the facet jointEur Spine J (2013) 22 (Suppl 3):S466–S470 S46912313. Okubadejo GO, Talcott MR, Schmidt RE, Sharma A, Patel AA,Mackey RB, Guarino AH, Moran CJ, Riew KD (2008) Perils ofintravascular methylprednisolone injection into the vertebralartery. 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Must we discontinue selective cervical nerve root blocks?: Report of two cases and review of the literature

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Must we discontinue selective cervical nerve root blocks?: Report of two cases and review of the literature

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