Print version ISSN 0034-7094
Rev. Bras. Anestesiol. vol.54 no.6 Campinas Nov./Dec. 2004
Accidental subarachnoid steroid injection during chronic lumbar pain treatment. Case report*
Inyección subaracnóidea inadvertida de corticóide en tratamiento de dolor crónico de la columna lumbar. Relato de caso
Simone Maria D'Angelo Vanni, TSA, M.D.
Doutora em Anestesiologia do CET/SBA do Departamento de Anestesiologia da FM-UNESP; Anestesiologista do Centro Paulista de Cirurgia Plástica de Jaú
OBJECTIVES: Before epidural steroids were used in chronic lumbar pain, subarachnoid
injection of these agents was the treatment of choice. Although still preconized
by some authors, this technique may lead to severe complications with neurological
sequelae. This report aimed at describing a case of accidental subarachnoid
injection of steroid associated to local anesthetics during epidural puncture
to treat lumbar pain.
CASE REPORT: Male patient, 46 years old, followed by neurosurgery for presenting right sciatic pain for 9 month, refractory to clinical treatment due to L4-L5 disk protrusion confirmed by CT scan, without neurological deficit. Epidural puncture for pain treatment was performed in L4-L5 with 17G needle and 10 mL solution were injected containing 4 mL of 0.25% bupivacaine, 80 mg methylprednisolone and 4 mL of 0.9% saline. Although there has not been CSF reflux, 5 minutes after injection there were sensory block in T4 and motor block in T6, associated to blood pressure and heart rate decrease.
CONCLUSIONS: Accidental subarachnoid injections with the association of steroids for pain relief may cause adverse effects. There are several risks, varying from mild transient symptoms to nervous injuries, including spinal cord injuries. Our patient had no sequelae from the accidental subarachnoid injection, probably because it has been a single injection.
Key Words: COMPLICATIONS: accidental injection; DRUGS, Steroids; PAIN, Chronic
Y OBJETIVOS: Antes que los corticóides fuesen utilizados en el espacio
peridural para el tratamiento de dolor crónico de la columna lumbar,
la inyección subaracnóidea de eses agentes era la elección.
La técnica subaracnóidea puede llevar a serias complicaciones
con secuelas neurológicas, aunque algunos autores aún la preconicen.
El objetivo de este relato es mostrar un caso de inyección inadvertida
de corticóide asociado a anestésico local en el espacio subaracnóideo,
cuando de la realización de punción peridural para tratamiento
de dolor en la columna lumbar.
RELATO DEL CASO: Paciente del sexo masculino, 46 años, acompañado por la neurocirugía por presentar ciatalgia a la derecha, hace 9 meses, rebelde al tratamiento clínico debido a que protrusión discal L4-L5 comprobada por estudio tomográfico, sin déficit neurológico. Realizada la punción peridural para tratamiento del dolor, en L4-L5 con aguja 17G, e inyectados 10 ml de solución conteniendo 4 ml de bupivacaína a 0,25%, 80 mg de metilprednisolona y 4 ml de solución fisiológica a 0,9%. A pesar de que no se constató reflujo de líquor, después de 5 minutos de la inyección ocurrieron bloqueos sensitivos en T4 y motor en T6, asociados a la disminución de la presión arterial y frecuencia cardíaca.
CONCLUSIONES: Las punciones subaracnóideas accidentales con asociación de corticóides para tratamiento de dolor pueden presentar complicaciones. Sus riesgos son innúmeros, variando de síntomas temporales leves a lesiones nerviosas e, incluso, en la médula espinal. El paciente en cuestión no presentó ninguna secuela de la inyección subaracnóidea inadvertida, probablemente por haber sido una inyección única.
Several pain centers use the association of steroids and local anesthetics in serial epidural blocks to treat pain related to vertebral column diseases, mainly in the intervertebral disk, because in many cases surgery is not the solution, with worsening of symptoms 1.
Anatomically, several lumbar structures have nociceptors and act as pain pathways in pathologic conditions; sensory innervation is located in the most external portion of the intervertebral disk ring and of the facet. So, in many pathologic facet and intervertebral disk processes there is lumbar pain with irradiation to gluteus, thigh and leg, and, if there is normal nervous pathway compression, there are paresthesias associated to severe pain 2.
There is an autoimmune mechanism proposed to radicular pain associated to disk injury, through which cytokines, including interleukins, nerve growth factor, interferon and tumor necrosis factor, play important role in radiculopathy-induced pain pathophysiology.
After nervous pathway compression, there is local inflammatory process with intraneural build up of serum proteins and fluids, increasing intraneural pressure, ischemia and axonal degeneration. Steroids relieve pain by decreasing inflammation by phospholipase A2 inhibition. This enzyme is responsible for arachidonic acid release from cell membranes at inflammation site, limiting prostaglandins and leucotriens production, which sensitize small neurons and increase pain. With changes in cell membrane patency, there are edema and venous congestion in response to inflammatory mediators with consequent abnormalities in nervous conduction and increased pain intensity and duration 3.
Male patient, 46 years old, followed by neurosurgery for presenting right sciatic pain for 9 month, refractory to clinical treatment due to L4-L5 disk protrusion confirmed by CT scan, without neurological deficit. Patient presented right Lasègues signal at physical evaluation. Visual analog scale evaluation has revealed 8 cm intensity with major ambulation difficulty. Patient had already been submitted to several clinical treatments with tricyclic antidepressants and anticonvulsants, as well as oral non-steroidal and steroidal anti-inflammatory drugs without any improvement.
Even not discarding surgical intervention, serial epidural blocks with the association of anesthetics and steroids were indicated due to the possibility of improving clinical symptoms with steroids through this administration route.
After left forearm venoclysis, 0.9% saline infusion was started with noninvasive blood pressure (120 x 70 mmHg), heart rate (82 bpm) and peripheral oxygen hemoglobin saturation (97%) monitoring. Patient was placed in the sitting position, lumbar region was sterilized with an antiseptic solution and an intradermal wheal is raised with 1% lidocaine (2 mL). Then epidural puncture was performed in L4-L5 with 17G Tuohy needle using loss of-resistance to air technique. Since no CSF reflux was observed at loss of resistance, 10 mL solution with 0.25% bupivacaine (4 mL), methylprednisolone (80 mg) and 4 mL saline were injected.
There has been no complaint during blockade and patient was immediately placed in the supine position. Five minutes later, there has been blood pressure (80 x 40 mmHg) and heart rate (50 bpm) decrease and 10 minutes later there has been sensory block in T4 and motor block in T6. Saline solution infusion rate was increased and 5 mg ephedrine were administered with improved blood pressure and heart rate.
Motor block recovery took 2h30 minutes, when patient was referred to the ward. Patient ambulated 20 hours after supine position rest. Hydration was maintained while patient was in bed, and he has not complained of headache, being able to walk normally without pain in the right leg (VAS = zero).
After 1-week follow up, patient has referred 80% pain improvement, being submitted to a new blockade 10 days after the first, without complications and with total improvement of symptoms.
After 3 months of follow up, and because there has been worsening of symptoms with less intense pain (VAS = 2 to 3), patient was referred to physical therapy rehabilitation with maintenance of anticonvulsant and tricyclic antidepressant.
At 2 years of follow up, patient still presents some pain episodes when performing intensive physical efforts, which improve with anti-inflammatory analgesics.
Robecci et al. 4, in 1952, have reported peri-radicular hydrocortisone to treat herniated lumbar disk based on the inflammatory theory of pain, but the technique has become more popular when Lievre et al. 5 have reported improvement of 5 out of 20 patients. However, these studies were poorly controlled and patients' follow up has not gone beyond 3 weeks.
Subarachnoid steroid therapy dates from 1961 when Gardner et al. 6 have attempted 30 mL of 1% procaine associated to 125 mg hydrocortisone in epidural infusion in 239 sciatic pain patients. Half of these patients had already been submitted to surgery without pain improvement. Due to 57% failure in the study, they have used spinal 80 mg methylprednisolone and 40 mg procaine in 75 patients with sciatic pain of undefined origin, with pain relief for more than 4 months in 60% of them, but details of results are not clear because authors do not mention control group or animal experiments.
Afterwards, the same group 7 has reported therapy in 100 patients with arachnoiditis with spinal methylprednisolone obtaining pain relief for more than 24 months in 60% of them, and around 1963, Sehgal et al. 8,9 had already treated more than 1000 patients with spinal methylprednisolone with 19 different diseases, from pain control failure to brain pseudo-tumor and Guillain-Barré syndrome. However, improvement duration has not been evaluated, results were not described and there was no control group.
Transition from subarachnoid to epidural therapy started in 1972, with Winnie et al. 10 who were successful with small methylprednisolone volume injections, showing that its action has been the therapeutic mechanism. In this study, 20 herniated disk patients were treated, 10 with subarachnoid injection and 10 with epidural injection of 80 mg methylprednisolone (2 mL), with 2-year pain improvement in both groups. Results with epidural injections were better. Epidural steroid injection to treat acute herniated disk has also been studied by Power et al. 11 in 1992, in 16 patients with recent disk extrusion, but 15 needed surgery in 7 days and 1 in 12 weeks, being the project abandoned because results were considered insufficient.
This transition was important due to the presence of several complications with subarachnoid injections. Accidental subarachnoid injection of methylprednisolone associated to local anesthetics in veins, ligaments or spinal space is present in 25% to 52% of caudal epidural procedures and 30% of lumbar procedures 12,13. Others studies have found adverse effects in 5% to 6% 13-18. Risks include spinal block 19, mild neurological symptoms 20,21 such as paresthesias and decreased muscle strength, pleocytosis of up to 3000/mm3 with high protein concentration, and generalized seizures due to irritating chemical effect 22. Urinary incontinence 23, constrictive arachnoiditis, aseptic meningitis, subarachnoid hemorrhage, neurogenic bladder 24,25 and nervous injuries (brain and spinal cord injuries) 17,26 may also be observed. Even though, some authors are still recommending subarachnoid injections 27,28.
As observed in our case, although CSF reflux was not visible at epidural puncture, certainly there have been total or at least partial solution transfer to the subarachnoid space, leading to the described symptoms with patient presenting evident motor and sensory block, which would not be expected with the volume and concentration of local anesthetics if it was deposited in the epidural space.
There were no complications apart from hypotension and bradycardia, in addition to no sequelae. The absence of neurological sequelae may be explained by the fact that there has been only one steroid injection in the subarachnoid space, since in most reported cases these sequelae are consequence of multiple non-accidental subarachnoid steroid injections.
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Submitted for publication
March 15, 2004
Accepted for publication July 20, 2004
* Received from CET/SBA do Departamento de Anestesiologia da Faculdade de Medicina de Botucatu (FMB UNESP), SP