Search Results

You are looking at 1 - 10 of 47 items for

  • Author or Editor: W. Elias x
Clear All Modify Search
Free access

Aaron E. Bond and W. Jeffrey Elias

OBJECTIVE

The goal of this study was to improve the predictability of lesion size during focused ultrasound (FUS) thalamotomy procedures.

METHODS

Treatment profiles and T2-weighted MRI (T2 MRI) studies obtained in 63 patients who participated in 3 clinical trials of FUS thalamotomy from February 2011 to March 2015 were reviewed retrospectively. Four damage estimate models were compared with lesion sizes measured on postprocedural T2 MRI. Models were based on 54°C × 3 seconds, 240 cumulative equivalent minutes at 43°C, and simple thermal threshold analysis, which recorded the maximum diameter that reached a temperature of at least 51°C and 54°C. Energy requirements per °C thermal rise above 37°C were also recorded.

RESULTS

Lesion diameters from T2 MRI correlated poorly from the day of the procedure to day 1 postprocedure (mean increase 78% [SD 79%]). There was more predictability of lesion size from day 1 to day 30, with a mean reduction in lesion diameter of 11% (SD 24%). Of the 4 models tested, the most correlative model to day 1 findings on T2 MRI was a 51°C threshold. The authors observed an increase in the energy requirement for each subsequent treatment sonication, with the largest percentage increase from treatment sonication 1 to treatment sonication 2 (mean increase 20% in energy required per °C increase in temperature above 37°C).

CONCLUSIONS

At the margins, 51°C temperature threshold diameters correlated best to lesion diameters measured at day 1 with T2 MRI. The lesion size from T2 MRI decreases from day 1 to day 30 in a predictable manner, much more so than from the day of the procedure to day 1 postprocedure. Energy requirements per °C rise above 37°C continuously increase with each successive sonication.

Full access

Introduction

Focused ultrasound surgery

W. Jeffrey Elias and Neal F. Kassell

Full access

Allan H. Friedman, W. Jeffrey Elias and Rajiv Midha

Surgery aimed at repairing damaged peripheral nerves has a long history. Refuting the timehonored nihilism of Hippocrates and Galen that an injured nerve cannot regain function, a few adventurous medieval surgeons attempted to repair severed nerves.6,8 However, the ability of a peripheral nerve repair to restore function was not generally accepted until 1800.1,4 Neurosurgeons, beginning with Harvey Cushing, have had an interest in repairing damaged peripheral nerves.2 Significant progress in the treatment of peripheral nerve injuries resulted from experience with the numerous injuries that occurred during World Wars I and II.3,7,12 Surgeons steadily defined the anatomy of peripheral nerves and developed techniques for decompressing and repairing peripheral nerves.9,11 Kline and Dejonge5 developed an intraoperative electrophysiological technique for detecting axons regenerating across a damaged segment of nerve. In the second 2 decades of the 20th century, distal nerve transfers were rediscovered whereby the proximal end of a less essential nerve is used to reinnervate the distal end of a nerve, providing a more vital function.10

Restricted access

W. Jeffrey Elias

Restricted access
Full access

W. Jeffrey Elias and Andres M. Lozano

Restricted access

W. Jeffrey Elias, Patrick Ireland and James B. Chadduck

Restricted access

Ricky Medel, Nader Pouratian and W. Jeffrey Elias

As > 95,000 spinal drug-delivery devices have been implanted since their inception in the 1980s, the recognition of associated adverse effects is essential. Since 1985, numerous reports have described the presence of catheter-tip granulomas. In the current case, the authors describe a less frequent complication of epidural bupivacaine precipitation. Regardless of origin, these unusual lesions have been increasingly recognized as a rare but potentially devastating complication of intrathecal infusions.

A 34-year-old woman with an intrathecal pain-pump delivering fentanyl, bupivacaine, and clonidine for thoracic outlet syndrome presented with rapidly progressive neurological deficits and increasing neck and upper-extremity pain. Neuroimaging disclosed a C7–T1 mass that was thought to be a hematoma that occurred after a recent epidural steroid injection. On emergency surgical decompression by laminectomy, a chalky mass containing viscous fluid was identified surrounding an epidurally located catheter. Histopathological examination revealed a proteinaceous mass consistent with drug precipitate enveloped by fibrosis and mild inflammation. Postoperatively, the patient recovered with minimal neurological deficit. The presentation and clinical relevance are discussed in conjunction with a review of the pertinent literature.

Catheter-tip masses are a rare complication of implantable drug-delivery devices occurring in < 3% of all patients with intrathecal catheters. Regardless of the anatomical site, the most common presenting features are neurological deficits, worsening pain, and increasing requirements for pain medication. Expedient diagnosis and management are essential for physicians treating patients with spinal infusion devices to prevent significant neurological sequelae. Further investigation is warranted regarding the use of bupivacaine as an adjunct in permanent spinal infusion systems.