Spinal injection procedures: a review of concepts, controversies, and complications

Real-time epidural anesthesia guidance using optical coherence tomography needle probe

Epidural anesthesia is one of the most widely used anesthesia methods. Due to lack of visual feedback to guide needle navigation, failure rate of epidural anesthesia is up to 20%, and the complication rate of peripheral nerve block approaches 10%, with the potential of permanent nerve damage. To address these difficulties, needle insertion under ultrasound guidance and fluoroscopy has been introduced. However, they do not provide adequate resolution and contrast to distinguish the tissue layers that the needle travels through or to specifically identify the epidural space. To improve the accuracy of epidural space identification, we developed a small hand-held optical coherence tomography (OCT) forward-imaging needle device for real-time epidural anesthesia surgery guidance and demonstrated its feasibility through ex vivo and in vivo animal experiments. With tissue structures visualized and differentiated at the needle tip, OCT needle imaging device will enhance clinical outcomes with regards to complication rates, induced pain, and procedure failure when compared to standard practice. Furthermore, this technology could be used in combination with ultrasound/fluoroscopy to enhance outcomes.

Epidural steroid injections for radicular lumbosacral pain: a systematic review

Most clinical guidelines do not recommend routine use of epidural steroid injections for the management of chronic low back pain. However, many clinicians do not adhere to these guidelines. This comprehensive evidence overview concluded that off-label epidural steroid injections provide small short-term but not long- term leg-pain relief and improvement in function; injection of steroids is no more effective than injection of local anesthetics alone; post-procedural complications are uncommon, but the risk of contamination and serious infections is very high. The evidence does not support routine use of off-label epidural steroid injections in adults with benign radicular lumbosacral pain.

Duration of fluoroscopic-guided spine interventions and radiation exposure is increased in overweight patients

BACKGROUND

The impact of patient body mass index (BMI) on image-guided spine interventions remains unknown. Higher BMI is known to complicate the acquisition of radiographic images. Therefore it can be hypothesized that the patient's body habitus can influence the delivery of a spinal injection.

OBJECTIVE

To quantify the impact of patient BMI on the length of fluoroscopy and procedure times during spine interventions.

DESIGN

Secondary analysis of 2 prospective observational studies.

SETTING

All injections were performed in an outpatient university setting.

PARTICIPANTS

A total of 209 patients in whom spine injections were performed (99 women), with a mean age of 54.6 years.

METHODS

The fluoroscopy times for 202 participants and total procedure times for 137 participants were recorded. Additional participant characteristics, including age, gender, BMI, and actual procedures performed, also were collected. Analysis of covariance and linear and nonlinear model analysis were performed to assess the effect of BMI on fluoroscopy and procedure times.

MAIN OUTCOME MEASUREMENTS

Fluoroscopy time and procedure duration times.

RESULTS

Participants had a mean age of 54.6 years, 51% were men, and 77% (n = 155) were overweight (BMI ≥25). Participants received the following interventions: 40 zygapophyseal joint injections, 33 medial branch nerve blocks, 113 transforaminal epidural injections, and 16 combined zygapophyseal joint injections and epidural injections. Gender, procedure number, and procedure type did not differ between groups. The overweight group demonstrated a 30% increase in mean fluoroscopy time and a 35% increase in mean procedure time. Controlling for other variables, we found that differences in fluoroscopy time and procedure time were significant (P = .032 and P = .031, respectively) between the 2 groups.

CONCLUSIONS

Significantly prolonged procedure time and fluoroscopy time in overweight patients increase the risks associated with spine interventions, not only to the patients but also to the operating room staff exposed to ionizing radiation.

Epidural needle with embedded optical fibers for spectroscopic differentiation of tissue: ex vivo feasibility study

Epidural injection is commonly used to provide intraoperative anesthesia, postoperative and obstetric analgesia, and to treat acute radicular pain. Identification of the epidural space is typically carried out using the loss of resistance (LOR) technique, but the usefulness of this technique is limited by false LOR and the inability to reliably detect intravascular or subarachnoid needle placement. In this study, we present a novel epidural needle that allows for the acquisition of optical reflectance spectra from tissue close to the beveled surface. This needle has optical fibers embedded in the cannula that deliver and receive light. With two spectrometers, light received from tissue is resolved across the wavelength range of 500 to 1600 nm. To determine the feasibility of optical tissue differentiation, spectra were acquired from porcine tissues during a post mortem laminectomy. The spectra were processed with an algorithm that derives estimates of the hemoglobin and lipid concentrations. The results of this study suggest that the optical epidural needle has the potential to improve the accuracy of epidural space identification.