Spinal injections: comprehensive review of the literature

The Rise of epidural and transforaminal steroid injections in the Spine: Commentary and a comprehensive review of the literature  | Surg Neurol Int. 2013; | Free Full Text PubMed PMC article

This very long and detailed article contains the results, both good and bad, of numerous studies that have been conducted on these injections.

Multiple type of spinal injections, whether epidural/translaminar or transforaminal, facet injections, are offered to patients with/without surgical spinal lesions by pain management specialists (radiologists, physiatrists, and anesthesiologists).

Although not approved by the Food and Drug Administration (FDA), injections are being performed with an increased frequency (160%), are typically short-acting and ineffective over the longer-term, while exposing patients to major risks/complications.

For many patients with spinal pain alone and no surgical lesions, the “success” of epidural injections may simply reflect the self-limited course of the disease. Alternatively, although those with surgical pathology may experience transient or no pain relief, undergoing these injections (typically administered in a series of three) unnecessarily exposes them to the inherent risks, while also delaying surgery and potentially exposing them to more severe/permanent neurological deficits.

other complications that go unreported/underreported:

• other life-threatening infections, spinal fluid leaks (0.4-6%),
• positional headaches (28%),
• adhesive arachnoiditis (6-16%),
• hydrocephalus, air embolism, urinary retention, allergic reactions, intravascular injections (7.9-11.6%),
• stroke, blindness, neurological deficits/paralysis, hematomas, seizures, and death.

Although the benefits for epidural steroid injections may include transient pain relief for those with/without surgical disease, the multitude of risks attributed to these injections outweighs the benefits.

Furthermore, for those with surgical lesions, injections may significantly delay requisite surgery, resulting in increased permanent neurological deficits

FREQUENCY OF EPIDURAL/TRANSFORAMINAL FLUOROSCOPIC SPINAL INJECTIONS

Rosas, et al. note the estimated frequency of low back pain/sciatica is prevalent, accounting for 13% (the second most common) of medical office visits in the US.[34] Furthermore, ESI are the “most commonly performed intervention in the management of chronic low back pain in the United States.”

Increase of 160% of steroid injections over 10 years driven by aging/desperate patients and monetary considerations

Summary: Dr. Manchikanti, Chairman of the American Society of Interventional Pain Physicians, observed that there has been a 160% increase in epidural injections from 2000 to 2010, and that too many are being performed without meeting proper criteria. Furthermore, 20% of physicians performing these procedures are not adequately trained. He raised the issue of “financial incentives” being responsible for this marked increase in procedures

BENEFITS FOR THE EFFICACY OF EPIDURAL INJECTIONS

In a prospective, randomized, controlled, double blind study involving 55 patients with lumbar radiculopathy, more patients receiving SNRIs of bupivacaine with betamethasone vs. bupivacaine alone opted over the long-term (13-28 months) for nonoperative management (“success”

Manchikanti, et al. determined that in 10,000 fluoroscopic-guided epidural injections, the risk of intravascular complications was highest for adhesiolysis (11.6%) and lumbar transforaminal procedures (7.9%), while the frequency of DPs was 0.5% (highest for adhesiolysis 1.8% followed by thoracic procedures 1.3%)

EFFICACY OF LUMBOSACRAL TRANSFORAMINAL STEROID INJECTIONS  (TFESI)

Summary: Ahadian, et al. documented the comparable safety and efficacy of transforaminal epidural injections utilizing 4 mg (33 patients), 8 mg (33 patients), and 12 mg (32 patients) of Dexamethasone at 4, 8, and 12 weeks post-injection.[2] By the 12th post-injection week, VAS scores declined to 26.6%, the ODI showed minimal residual findings, and there were no AEs.

Summary: Benny, et al. documented that lumbosacral transforaminal injections (8 of 10 randomized control studies and 9 prospective trials) performed under CT or fluoroscopic guidance injections showed positive short- and long-term outcomes.

Summary: Roberts, et al. identified nine randomized studies, which utilized fluoroscopy to perform transforaminal epidural steroid injections (TFESI) for the treatment of radiculopathy. They noted that TFESI were not only better than placebo, but also were superior to interlaminar and caudal injections. The one exception was subacute/chronic radiculopathy, where a single TFESI was as effective as a single transforaminal injection of bupivacaine or saline.

Summary: Schaufele, et al. retrospectively analyzed the efficacy of TFESI vs. TLESI, and found that those undergoing TFESI experienced better resolution of pain, required fewer subsequent injections, and fewer subsequent operations

Summary: Bilateral TFESI produced more effective control of symptoms in patients with SS vs. TLESI. This was likely attributed to higher concentrations of steroids achieved in the ventral epidural space vs. dorsal compartment, which is typically occupied by not only scar and fibrosis, but also marked hypertrophy/OYL that blocks steroid dissemination.

COMPARABLE EFFICACY OF DIFFERENT SPINAL INJECTIONS

Summary: In the Wilson-MacDonald, et al. study, 93 patients, all considered potential surgical candidates, exhibited comparable 2-year outcomes (Oxford Pain Chart and ODI) utilizing ESIs or intramuscular injections of steroids combined with a local anesthetic.[42] They found no substantial difference over the longer term, and the incidence of subsequent surgery was similar for both groups.

RISKS OF EPIDURAL/TRANSFORAMINAL EPIDURAL SPINAL INJECTIONS (ESI)

Summary: Deyo observed that in multiple clinical trials utilizing epidural spinal injections performed at the University of Washington, that “seven clinical trials showed the injections were helpful, another seven found them no better or even worse than a placebo, and three (had) unclear results.”[3] He also observed other risks of these injections that included: Infection, injections into the spinal fluid, intravascular injections, nerve damage, hemorrhages, and archnoiditis.

Summary: Valat, et al. compared the efficacy of ESIs vs. isotonic saline, finding “the efficacy of isotonic saline administered epidurally for sciatica cannot be excluded, but ESIs provide no additional improvement.”

Summary: Carette, et al., in a double-blind, randomized trial, determined that for 158 patients with herniated discs evaluated utilizing the ODI at 3, 6, 12 weeks and 1 year following injections, that even if epidural methylprednisolone resulted in some short-term benefits, it “offers no significant functional benefit, nor does it reduce the need for surgery.”

Summary: Arden, et al. evaluated the efficacy of three ESI vs. interligamentous saline injections (3 weeks apart) in patients with unilateral sciatica for 1-18 months.[5] They found that ESI offered transient benefit in symptoms at 3 weeks in patients with sciatica, but no sustained benefits in terms of pain, function, or need for surgery. From 6 to 52 weeks post-injection, “no benefit was demonstrated.”

Summary: Manchikanti, et al. reported on 43,000 intermittent fluoroscopically guided facet joint nerve blocks injections performed during 7500 visits, and observed the following complications: Intravascular injection (11.4%), local bleeding (76.3%), oozing (19.6%), and local hematoma with profuse bleeding (1.2%) with less than 1% experiencing other notable complications

SAFETY OF CERVICAL EPIDURAL STEROID INJECTIONS

Summary: Castagnera, et al. noted that long-term results (48 post-injection months) did not differ between two groups of patient with nonsurgical cervical disease, receiving one dose of epidural steroids with lidocaine (S) vs. steroids with morphine sulfate (S + M).[11] Success rates were 78.5% (S), and 80% (S + M), and specific pain relief was also comparable: (86.8% (S) and 86.9% (S + M)

Summary: In the Botwin, et al. series involving 157 patients undergoing 354 CESIs at the C6-C7 or C7-T1 levels, although 16.8% of patients exhibited complications, none required hospital stays or developed persistent morbidity

Summary: Abbasi, et al. concluded that a review of the literature revealed a 0-16.8% incidence of complications associated with cervical epidural spinal injections, but acknowledged that the design of most studies was suboptimal (e.g., future prospective, randomized studies were warranted)

Summary: Rowlingson and Kirschenbaum series, performing 45 CESIs in 25 patients with cervical radiculopathy, resulted in a 64% incidence of good or excellent responses

Summary: Performing 1036 extraforaminal cervical nerve blocks in 844 patients resulted in no major but 14 (1.66%) minor complications that more frequently occurred with deep rather than superficial injections.

Summary: Waldman evaluated 215 patients undergoing 790 cervical epidural nerve blocks. He found the following complications: Two DPs, three vasovagal events, and one delayed superficial infection

RISKS OF CERVICAL EPIDURAL STEROID INJECTIONS

Summary: In Anderberg, et al. prospective randomized study of 40 patients undergoing either cervical ESI/local anesthetic vs. sterile saline/local anesthetic, at 5 post-injection weeks, patients receiving steroid injections had less pain, but not over the long-term.

Summary: Scanlon, et al. cited eight instances of inadvertent intravascular injections leading to brain and spinal cord injury and identified an additional four cases of major particulate corticosteroid embolic injury to the cerebellum and brainstem in the literature.[36] In their own survey of members of the American Pain Society, the 21.4% response rate (287 of 1340) revealed 78 complications including: 16 vertebrobasilar brain infarcts, 12 cervical spinal cord infarcts, and 2 combined brain/spinal cord infarcts, with 13 fatal outcomes.

RISKS OF INADVERTENT INTRAVASCULAR INJECTIONS DURING ATTEMPTED CERVICAL STEROID INJECTIONS

Summary: In the Bose, et al. study, a patient developed quadriplegia and a respiratory arrest following an attempted CESI at the C6-C7 level; they concluded that it was likely a “vascular event” that left the patient with a major permanent neurological deficit.

Summary: Following a left C6 TFESI, Ludwig’s 53-year-old patient developed left arm and bilateral lower extremity weakness. The MR confirmed hyperintense intramedullary cord signal changes within 24 hours extending from the odontoid to the C4-C5 level, consistent with a diffuse vascular infarction.

Summary: Karasek and Bogduk noted the adverse consequences of performing a C6-C7 transforaminal injection utilizing local anesthesia that resulted in an inadvertent injection into a cervical radicular artery.[17] Their patient’s immediate quadriplegia resolved within 20 minutes; however, had this been a steroid injection, particulate matter may have acted as an embolus and caused a permanent injury.

Summary: Stabuer and Nazari’s 67-year-old female following a C6-C7 epidural cervical steroid injection sustained pneumocephalus and a cardiopulmonary arrest.[38] The latter was likely attributed to blockade of the sympathetics resulting in bradycardia/arrest.

MULTIPLE COMPLICATIONS OF EPIDURAL OR TRANSFORAMINAL INJECTIONS

Summary: Risks of epidural/transforaminal injections include: Infection, epidural hematoma (0-1.9%), intravascular injections, nerve damage, CSF fistulas/headaches, air embolism, urinary retention, allergic reactions, seizures, blindness, and others

Summary: Epidural/TFESIs are associated with infection rates varying from 1% to 2%, with more serioius infections observed in 0.1% of patients.

Summary: Kainer, et al. evaluated the recent outbreak of fungal infections that recently followed epidural or paraspinal injections of preservative-free MPA from one compounding pharmacy in New England.[16] They reported that 66 patients, averaging 69 years of age exhibited meningitis (73%), cauda equina syndrome or focal infection (15%), or posterior circulation stroke/with or without meningitis (12%). Despite treatment with Voriconazole (61 patients: 92%) supplemented in 35 patients (53%) with liposomal amphotericin B, 9 patients (12%) died, and 7 of the 9 had sustained a stroke.

Summary: In the Zimmerer, et al. study of 36 patients with SEA, 4 patients had undergone spinal injections and comprised 11.1% of patients in the overall series, but a higher 20% of those with secondary (surgery vs. injection) reasons for developing SEA

RISKS OF DURAL PUNCTURE (DP)/CEREBROSPINAL FLUID FISTULAS/PERSISTENT HEADACHES

Summary: In a survey of 36 academic institutions involving 137,250 women in labor/deliveries, Berger, et al. found the frequency of inadvertent DPs occurring during epidural analgesia ranged from 0.4% to 6%.[7] Notably, EBPs failed in 86% of patients, and 44% experienced persistent headaches.

Summary: Webb, et al. reported a higher baseline but comparable maximum risk (0.4-6%) of inadvertent DP utilizing a 17-gauge Tuohy needle to administer epidural analgesia for women in labor.[41] The frequency of postural headaches was a higher 70-80%, with 28% exhibiting chronic headaches compared with only a 5% frequency of headaches for matched controls.

Summary: Goodman, et al. noted two cases in which TLESI and TFLEI resulted in dural and subdural punctures.[13] Interventionalists should recognize the different patterns of contrast dissemination, and should particularly avoid the direct injection of steroids into the epidural compartmen

ADHESIVE ARACHNOIDITIS

Summary: When Lima, et al. performed intrathecal injections of normal saline vs. methylprednisolone into dog models, methylprednisolone resulted in the following histological changes: “Meningeal thickening, lymphocytic infiltrates in the blood vessels, adhesion of pia, arachnoid, and dura matter with nerve roots were surrounded by fibrosis and necrosis of the spinal cord.

Summary: Rodriguez Luna, et al. reported that adhesive arachnoiditis occurs in between 6% and 16% of patients having primary or revision lumbar surgery.

Summary: Koerts, et al. reported that 86% of cases of spinal adhesive arachnoiditis occur in the lumbar region, and are due to: Contamination of the subarchnoid space with blood (e.g., CSF leak/dural tear), infection, myelography (especially oil-based), ESIs, spinal surgery (disc/stenosis), and trauma

Summary: Riley and Spiegel documented subdural hematoma and subdural hematoma with adhesive arachnoiditis with chronic sacral radiculopathy as the result of utilizing large volume EBPs in two respective patients with postdural puncture headaches.

CONCLUSION

Adhesive arachnoiditis occurs in between 6% and 16% of patients undergoing primary or revision lumbar surgery.

Over 86% of these cases occur in the lumbar region, and are due to:

• Contamination of the subarchnoid space with blood (e.g., CSF leak/dural tear),
• infection,
• myelography (especially oil-based),
• ESIs,
• spinal surgery (disc/stenosis), and
• trauma.

Horror Stories:

In one study, a 40-year-old patient developed an irreversible cauda equina syndrome attributed to adhesive arachnoiditis following lumbar surgery.

In a second case, a 45-year-old male developed delayed adhesive arachnoiditis, hydrocephalus, and a cauda equina syndrome several years following multiple spinal operations.

In a third study, two patients who were treated for postural headaches with EBPs (Epidural Blood Patches), respectively, developed a subdural hematoma and subdural hematoma with adhesive arachnoiditis/chronic sacral radiculopathy due to large volumes of epidural blood utilized to perform these patches, and in the latter case, the number of patches placed in a short period of time.

Insurers promoting unsafe practices

Many insurance companies motivate physicians (with higher reimbursements) to perform epidural injections in their office (typically without fluoroscopy, which is often not reimbursed (yet costs $100.00) to avoid facility fees. Fees quoted for epidural injections performed in an ASC averaged $107 vs. $247 in an office; facility fees varied typically from $300 to $650. I insurance companies should be admonished for promoting unsafe practices.