Lumbar Epidural Contrast Spread Patterns for the Interlaminar Approach: Three-Dimensional Analysis Using Antero-Posterior, Lateral, and Contralateral Oblique Views.

OBJECTIVE: To describe and analyze lumbar epidural contrast spread patterns in antero-posterior (AP), lateral, and contralateral oblique (CLO) views. METHODS: Lumbar epidural contrast spread patterns after interlaminar injection were prospectively collected in AP, lateral, and several CLO views and analyzed for multiple variables; three-dimensional mapping was also performed. RESULTS: Epidural contrast patterns were prospectively analyzed in 28 subjects. The median volume of contrast injected was 2 mL; the AP view was more sensitive than the lateral view to detect foraminal uptake (13/28, 46%, 95% confidence interval [CI] = 27-66%, vs 7/28, 25%, 95% CI = 11-45% subjects). CLO view demonstrated the most consistent location for epidural contrast spread, with contrast contacting the ventral laminar margin in 28/28 (100%, 95% CI = 87-100%) patients. The most common location of contrast spread in the lateral view was at the facet joint lucency, with only 8/28 (29%, 95% CI = 13%-49%) subjects showing contrast contacting the spinolaminar junction. Lateral view was more sensitive than the CLO view in ventral epidural contrast spread detection. The extent and distribution of the spread did not bear any relationship to the volume injected or to the needle location in AP view. CONCLUSIONS: CLO view provides the most consistent landmark for lumbar epidural contrast spread, and lateral view is most suited to confirming ventral epidural spread. The AP view may be the most optimal for determining target access when considering access to the dorsal root ganglia; in an individual patient, the volume injected and needle location in AP view do not reliably predict target access. The volume to be injected and the need to re-access or obtain multisite access must be prospectively determined, based upon observation of the spread.

Discontinuation of Chronic Opiate Therapy After Successful Spinal Cord Stimulation Is Highly Dependent Upon the Daily Opioid Dose.

OBJECTIVES: The aim of this study was to determine if any of the factors recorded on a standard clinical history of a patient considered for spinal cord stimulation (SCS) would be associated with reduction or cessation of opioids following implantation. DESIGN: Retrospective, single academic center. METHODS: Patients included in the chart analysis underwent implantation of percutaneous SCS devices from 1999 to 2015 with follow-up until the end of September 2018. Patients who achieved at least an average of 50% pain reduction were included for analysis of daily opioid intake. Patients were then divided into 4 groups that included no opioid use, stable opioid daily dose, weaned opioid dose, and complete cessation of opioids. Statistical methods were used to analyze for associations between opioid intake after SCS insertion and usual elements of a clinical history, including adjuvant medications, numeric pain rating, past medical history, psychiatric illness, substance abuse, employment, and smoking history. RESULTS: In a group of 261 patients who had undergone implantation, 214 met the criteria for analysis and had a median age of 50 years, with majority having the diagnoses of failed back surgery syndrome and complex regional pain syndrome. The only factor that was associated with complete cessation of opioid use was a median dose of 30 mg of morphine per day (P < 0.01) and was observed in 15% of subjects who used opioids preoperatively. CONCLUSION: The elimination of opioid dependence following initiation of SCS therapy is highly dependent on the daily dose.

Explantation of Percutaneous Spinal Cord Stimulator Devices: A Retrospective Descriptive Analysis of a Single-Center 15-Year Experience.

OBJECTIVES: The aims of this study were to identify the reasons for explanation of spinal cord stimulator (SCS) devices and to further quantify the proportions and time lines of these causes of explantation in order to determine improvement opportunities for the development of best practices. DESIGN: Retrospective, single academic center. MATERIALS AND METHODS: Patients who were implanted with percutaneous SCS devices from 2002 to 2015 and with follow-up available until the end of September 2017 were included in this retrospective chart analysis. RESULTS: Of the 356 patients trialed, 252 underwent implantation of an SCS device with a permanent to trial ratio of 71%. Of the patients who had a permanent implant, 50% had failed back surgery syndrome, 25% had complex regional pain syndrome, and 25% had other diagnoses. At the end of the study period, the explantation rate was 30%. The causes for explantation included biological complications (26.6%), paresthesia limitations or side effects (26.6%), hardware complications (13.3%), ineffective pain control (28%), and no further need for stimulation therapy (5.3%). CONCLUSIONS: Device removal is not uncommon, and opportunities to enhance the long-term success of SCS devices do exist. These include modification of trialing methods, achieving better paresthesia overlay, using magnetic resonance imaging (MRI) conditional equipment, development of robust technologies and hardware to reduce equipment malfunction, and improving efficacy with new innovative wave forms.

The Long-Term Durability of Multilumen Concentric Percutaneous Spinal Cord Stimulator Leads.

BACKGROUND: Lead fracture is a well-known complication of cylindrical spinal cord stimulator leads. In order to reduce this complication, anchor design and techniques have been modified, but internal lead design has received little attention. OBJECTIVES: The goal of this study was to study the impact of lead design by a retrospective determination of the fracture rate of multilumen concentric (MLC) 8-contact leads. STUDY DESIGN: Retrospective chart review. SETTING: University teaching hospital. METHODS: A registry of spinal cord stimulator implants and corresponding billing data were used to identify patients. Procedural details were reviewed for technique, lead insertion, anchoring details, manufacturer, and lead longevity from 2002 to 2014. Data storage was in RedCap data-capturing software (REDCap eData Collection web-based application). All analyses were performed using SAS 9.3 (SAS Institute, Cary, NC, U.S.A.). RESULTS: In a near 12"-year time period, 172 patients received 305 permanently implanted 8-contact leads, with an overall fracture rate of 4.3%. Of these, 191 leads were of the MLC design. No lead fracture was observed in the MLC leads over an average 4.5 years of follow-up. LIMITATION: Retrospective single center. CONCLUSION: MLC lead design has the potential to significantly mitigate lead fracture.

A Temporary vs. Permanent Anchored Percutaneous Lead Trial of Spinal Cord Stimulation: A Comparison of Patient Outcomes and Adverse Events.

OBJECTIVES: A trial of spinal cord stimulation (SCS) is a prerequisite to determine efficacy of the therapy prior to placement of a permanent implanted system. A trial may be conducted employing a percutaneously placed temporary cylindrical lead or via a permanently anchored cylindrical lead placed and subsequently secured via open surgical method. There has been little investigation comparing the two methods of trial. This study is a comparative analysis of the two methods both for prediction of success as well as associated morbidity. STUDY DESIGN: Retrospective chart review. MATERIALS AND METHODS: SCS outcomes of percutaneous temporary lead trial or the temporary lead (TL) group and permanent anchored lead trial or permanent lead (PL) group were analyzed for lack of relief, poor paresthesia coverage, false positive trial phase, fading relief, and biological complications. RESULTS: Outcome data was analyzed for 148 patients in the TL group and 138 patients in the PL group. In comparing the two trial methods, false positive rate of trial was higher (p < 0.05) in the PL group as compared to the TL group (6.35 vs. 1.35%). Cumulative wound infections (6.52 vs. 1.35%), and poor wound healing (4.35 vs. 0%) were also significantly higher in the PL group. Rate of success in the trial phase was equal in both groups. CONCLUSION: The percutaneous temporary lead trial group was associated with fewer false positives and wound related complications as compared to permanent anchored lead trial group. There was very little technical advantage of routinely anchoring the trial lead.

Percutaneous Translaminar Facet Cyst Rupture and Epidural Access-Description of a Novel Technique.

Synovial cysts of the lumbar zygapophysial joints can be treated by percutaneous injection of corticosteroids, with distension and rupture of the cyst. Some cysts can be difficult to access, particularly when they lie deep in relation to the lamina. This technical report describes a fluoroscopy-guided technique for accessing sublaminar pathology. Crucial to the safety of the technique is visualization of the ventral margin of the lamina using a contralateral oblique view, and controlling and limiting the insertion of the needle such that only its tip passes the lamina.

Cervical Epidural Contrast Spread Patterns in Fluoroscopic Antero-Posterior, Lateral, and Contralateral Oblique View: A Three-Dimensional Analysis.

Objective: To describe and to analyze cervical epidural contrast patterns seen in antero-posterior (AP), contralateral oblique (CLO), and lateral view. To identify factors that might help in predicting contrast distribution pattern and extent. Method: Spread of contrast in the cervical epidural space was prospectively studied in AP, lateral, and three CLO views. Results: CLO view showed contrast spread of variable thickness with its posterior margin overlying the ventral interlaminar line (VILL). In the lateral view, the spread was also of variable thickness, but the posterior margin of the contrast lay on the spinolaminar line in only 10 of 24 patients. Ventral contrast spread was not visualized in any patient. In the AP view, bilateral spread was seen in 14 of 24 subjects, and nerve root spread was seen in 16 of 24 subjects. No association of the pattern of spread or dispersion was seen to patient age, volume injected, or needle location. Conclusions: The CLO view provides a consistent radiological landmark for the posterior margin of contrast in the dorsal epidural space; the lateral view fails to provide such a consistent landmark. The thickness of the spread is variable, both in the CLO and in the lateral view. Thick spread extending into the foramen in the CLO view and over the articular pillars in the lateral view is frequent and should not be misconstrued as subdural or intrathecal spread. In contradistinction to previous studies, true ventral spread was not seen in any patient. When using low volumes, contrast spread is independent of patient age, volume injected, or needle tip location in the AP view.

Contralateral oblique view is superior to lateral view for interlaminar cervical and cervicothoracic epidural access.

OBJECTIVE: The purpose of this study was to compare the reliability of the lateral fluoroscopic view and several contralateral oblique (CLO) views at different angles in visualizing and accurately predicting the position of the needle tip at the point of access in the posterior cervical and cervicothoracic epidural space. DESIGN: After the epidural space was accessed but before confirmation with contrast fluoroscopy, we prospectively obtained fluoroscopic images at eight different angles. Subsequent contrast injection confirmed epidural spread. Needle tip visualization and location of needle relative to bony landmarks were analyzed. RESULTS: The needle tip was clearly visualized in all CLO projections in all 24 subjects. CLO view at 50 degrees and at obliquity measured on magnetic resonance imaging (MRI) images provided the most consistent needle tip location. In these views, the epidural space was accessed at or just beyond the ventral laminar margin at the ventral interlaminar line or within the proximal half of the predefined CLO area in all patients. The needle tip was poorly visualized in the lateral view and the location of the needle tip was less well defined and independent of the needle location in the anteroposterior (AP) view. CONCLUSIONS: This study provides evidence that during cervical and cervicothoracic epidural access, the CLO view at 50 degrees and at MRI-measured obliquity is superior to the lateral view for the purpose of needle tip visualization and in providing a consistent landmark for accessing the epidural space. This article also introduces the concept of zones to describe needle position in the cervical and cervicothoracic spine in AP, lateral, and oblique views.