Contralateral Oblique View Is Superior to the Lateral View for Lumbar Epidural Access.

OBJECTIVE: The purpose of this study was to perform a comparative analysis of the contralateral oblique (CLO) view and the lateral view for lumbar interlaminar epidural access. DESIGN: After the epidural space was accessed, fluoroscopic images at eight different angles (antero-posterior view, multiple CLO, and lateral view) were prospectively obtained. Visualization and location of needle tip relative to bony landmarks were analyzed. The epidural location of the needle was subsequently confirmed by contrast injection and analysis in multiple views. RESULTS: Visualization of the needle tip and the relevant radiologic landmarks was superior in the CLO view. The needle tip location in the epidural space was most consistent at a CLO angle of 45°. CONCLUSION: This study shows that the CLO view for lumbar interlaminar epidural access offers clear advantages over the lateral view on many clinically important grounds: the needle tip visualization is better, the important radiological landmarks are better visualized, and the needle tip when placed in the epidural space presents a more precise relationship to these landmarks. All of these differences were highly significant. Thus, when using this view, the needle may be directly placed in very close vicinity to the epidural space and true loss of resistance expected soon thereafter. In addition, this view provides the ability to plot the cranio-caudad needle trajectory. The combination of these factors is likely to improve the ease and efficiency of epidural access. The crisp visualization of the final moments of epidural access could also translate to improved safety and accuracy. In light of this, it is suggested that a CLO view at 45° be considered the preferred view for gauging needle depth during interlaminar lumbar epidural access.

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.

Computed tomography-based muscle attenuation and electrical impedance myography as indicators of trunk muscle strength independent of muscle size in older adults.

OBJECTIVE: The aim of this study was to examine the associations of computed tomography-based x-ray attenuation and paraspinal electrical impedance myography measures of trunk muscles with absolute and relative (normalized by body weight) trunk extension strength, independent of muscle cross-sectional area. DESIGN: This is a cross-sectional study of mobility-limited community-dwelling older adults (34 women, 15 men; mean [SD] age, 78.2 [7.2] yrs) recruited from within an existing prospective research cohort. Trunk extension strength, computed tomography-based trunk muscle cross-sectional area and attenuation at L4 level, and paraspinal electrical impedance myography measures were collected. RESULTS: Attenuation was positively correlated with absolute and relative strength for multiple muscle groups (r = 0.32-0.61, P < 0.05). Paraspinal electrical impedance myography phase was positively correlated with paraspinal attenuation (r = 0.30, P = 0.039) and with relative strength (r = 0.30, P = 0.042). In multivariable linear regressions adjusting for sex and cross-sectional area, attenuations of the anterior abdominal muscles (semipartial r = 0.11, P = 0.013) and combined muscles (semipartial r = 0.07, P = 0.046) were associated with relative strength. CONCLUSIONS: Although attenuation was associated with relative strength, small effect sizes indicate limited usefulness as clinical measures of muscle strength independent of muscle size. However, there remains a need for additional studies in larger and more diverse groups of subjects.

Electrical impedance myography in the diagnosis of radiculopathy.

INTRODUCTION: We sought to determine whether electrical impedance myography (EIM) could serve as a diagnostic procedure for evaluation of radiculopathy. METHODS: Twenty-seven patients with clinically and radiologically diagnosed cervical or lumbosacral radiculopathy who met a "gold standard" definition underwent EIM and standard needle electromyography (EMG) of multiple upper or lower extremity muscles. RESULTS: EIM reactance values revealed consistent reductions in the radiculopathy-affected myotomal muscles as compared with those on the unaffected side; the degree of asymmetry was associated strongly with the degree of EMG abnormality (P < 0.001). EIM had a sensitivity of 64.5% and a specificity of 77.0%; in comparison, EMG had a sensitivity of 79.7% but a specificity of 69.7%. CONCLUSIONS: These findings support the potential for EIM to serve as a new non-invasive tool to assist in diagnosis of radiculopathy; however, further refinement of the technique is needed for this specific application.

Spinal cord stimulation for radicular pain following retained bullet in the spinal canal.

We are reporting on the implantation of a spinal cord stimulator to treat intractable radicular pain following a retained bullet fragment in the spinal canal. Such retained fragments are associated with risks including pain, neurological deficit, infection, toxic effects, and migration. Our patient was a young man with radicular pain and history of a gunshot entering the abdomen. Computed tomography of the spine had revealed a nearly complete bullet in the right paracentral canal at L4, partially extending into the lateral recess. He presented 17 months after his injury with gradually worsening pain and parasthesias radiating from the back to the whole right leg and foot. There was no weakness. As the patient had failed conservative therapy, procedural options were considered. In this case, the potential benefits of epidural steroid injection by any approach might not have outweighed risks of infection, related to foreign body and local steroid, or possible migration due to mechanical forces during injection. As he may well need repeated epidural steroid injections to manage his pain, this increases his risk for infection. A percutaneous trial spinal cord stimulation lead was placed, with epidural entry well away from the bullet. After good results, a permanent system was implanted. There was no evidence of infection or migration, and excellent pain relief was achieved. Bullets and other foreign bodies retained in the spinal canal can cause progressive neurologic symptoms through reactive tissue formation and compression. Spinal cord stimulation can relieve radicular pain while avoiding risks associated with altering the location of the offending foreign body.

Utilizing a handheld electrode array for localized muscle impedance measurements.

INTRODUCTION: Electrical impedance myography (EIM) is a noninvasive technique used for assessment of muscle health in which a high-frequency, low-amplitude electric current is applied to the skin overlying a muscle, and the resulting surface voltage is measured. We have previously used adhesive electrodes, application of which is inconvenient. We present data using a handheld electrode array (HEA) that we devised to expedite the EIM procedure in a clinical setting. METHODS: Thirty-four healthy volunteers and 24 radiculopathy subjects underwent EIM testing using the HEA and adhesive electrodes. RESULTS: The HEA was shown to have good test-retest reproducibility, with intraclass correlation coefficients as high as 0.99. HEA data correlated strongly with data from adhesive electrodes, ρ = 0.85 in healthy volunteers (P < 0.001) and ρ = 0.75 in radiculopathy subjects (P < 0.001). CONCLUSIONS: These data support the potential use of a handheld array for performing rapid localized surface impedance measurements.

Musculocutaneous nerve injury after simulated freefall in a vertical wind-tunnel: a case report.

We report a case of a skydiver with isolated musculocutaneous nerve injury, which occurred after prolonged positioning of the arm during simulated freefall in a vertical wind-tunnel. Musculocutaneous nerve injury is rare, and the mechanism of isolated injury to this nerve is not entirely understood. Isolated peripheral nerve injuries such as this easily mimic other injuries and can be difficult to diagnose. The skydiver complained of right arm weakness and numbness that began after training in a vertical wind-tunnel. Exam revealed weakness in right elbow flexion and forearm supination, and diminished sensation in the right lateral forearm. Electrodiagnostic testing revealed a decreased amplitude in the right lateral antebrachial cutaneous nerve sensory nerve action potential, and fibrillations and positive sharp waves in the biceps and brachialis muscles. By 5 months, the subject reported complete sensory and motor recovery. Physical and electrodiagnostic findings corresponded to the distribution of the musculocutaneous nerve. The mechanism of injury was likely the prolonged abducted, extended, and externally rotated position of the shoulder during simulated freefall. Although isolated nerve injuries are uncommon, unusual activities and physiologic demands of athletes can result in such injuries. It is important to be aware of peripheral nerve injuries to facilitate proper diagnosis and management.