Ahead of Print: Neuropsychiatric Changes after Stereotactic Surgery

Background: Stereotactic central lateral thalamotomy (CLT) has been applied as a treatment for chronic intractable neuropathic pain. However, it is not clear whether this intervention influences the emotional and cognitive impairments observed in chronic neuropathic pain patients.

Objective: To investigate neuropsychological functions and emotional processing in patients with chronic neuropathic pain compared to healthy volunteers, and to explore the neuropsychiatric effect of the CLT.

Methods: We investigated pain ratings, cognitive functions, emotional processes, and personality variables before and after surgery in eight patients with intractable neuropathic pain. Patients were tested before and 3 months after CLT using neuropsychological tests, clinical scales for depression, anxiety, anhedonia and anger regulation, a personality test, and two experimental tasks testing the theory of mind as well as the ability to recognize facial emotional expressions. Nine age- and gender-matched control subjects were tested once using the same procedure.

Ahead of Print: Superficial Temporal Artery Dissection

Background: Dissection of the superficial temporal artery (STA) is often required in preparation for a bypass procedure. Traditionally, dissection of the STA involves a direct cutdown on the artery after marking the course of the artery on the skin with the help of a Doppler ultrasound probe.

Objective: We describe a method that takes advantage of the position of the STA superficial to the temporal fascia.

Methods: The technique was employed in a total of 38 procedures among 32 patients, for creation of synangiosis or Extracranial-Intracranial STA bypasses. The STA was dissected using a blunt malleable brain retractor, which was inserted into the subgaleal plane directly over the STA, allowing for creation of a linear incision and concurrent protection of the STA in its bed. Either CT- or catheter-based angiography was used to evaluate the patency postoperatively.

Ahead of Print: O-arm for DBS

Background: Deep brain stimulation surgery has an average accuracy of 2-3 mm (range 0-6 mm). Intra-operative detection of track location may be useful in interpreting physiologic results and thus limit the number of brain penetrations, as well as decrease the incidence of reoperations. The O-arm has been utilized to identify DBS lead position; however, early results have indicated a significant discrepancy with lead position on postoperative imaging.

Objective: This prospective study was conducted to determine the accuracy and reliability of fiducial and track localization and to assess the accuracy of O-arm image based registration. The CT image was considered the gold standard, and so for this study, the locations of all objects on the O-arm image were compared with their CT location.

Methods: 33 DBS surgeries were performed utilizing the O-arm to image each track with detailed analysis of fiducial and track localization accuracy. 21 subsequent surgeries were performed using O-arm registration. Only the final lead position was assessed in these individuals.

Ahead of Print: Minimally-invasive Surgery for Subinsular Tumor

Background and Importance: To describe the novel use of AutoLITT(R) System (Monteris Medical, Winnipeg, MB) for focused laser interstitial thermal therapy (LITT) using intraoperative MRI and stereotactic image guidance for the treatment of metastatic adenocarcinoma to the left insula.

Clinical Presentation: The patient is a 61-year-old right-handed male with a history of metastatic adenocarcinoma of the colon. He has previously undergone resection of multiple lesions, Gamma Knife and whole brain radiation. Despite treatment to a left insular tumor, serial imaging revealed that the lesion continued to enlarge. Given the refractory nature of this tumor to radiation and the deep seated location, the patient elected to undergo LITT treatment. The center of the lesion and entry point on the scalp were identified using STEALTH (Medtronic, Memphis, TN) image-guided navigation. The AXiiiS(R) Stereotactic Miniframe (Monteris Medical, Winnipeg, MB) for the LITT system was secured onto the skull and a trajectory was defined to achieve access to the centroid of the tumor. After performing a burr hole, a gadolinium template probe was inserted into the AXiiiS base. The trajectory was confirmed via an intraoperative MRI and the LITT probe driver was attached to the base and CO2-cooled, side-firing laser LITT probe. The laser was activated and thermometry images were obtained. Two trajectories, posterior-medial and antero-lateral, produced satisfactory tumor ablation.

Ahead of Print: Accuracy of Frame-Based Stereotactic MRI vs Frame-Based Stereotactic Head CT Fused with Recent MRI for Post-Implantation DBS Lead Localization

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BACKGROUND: Introduction of the portable intraoperative CT scanner provides for a precise and cost-effective way of fusing head CT images with high Tesla MRI for exquisite definition of soft tissue needed for stereotactic targeting.

OBJECTIVE: To evaluate the accuracy of stereotactic electrode placement in patients undergoing DBS by comparing frame-based post-implantation intraoperative CT images (iCT) fused to a recent 3T-MRI to frame-based post-implantation intraoperative MRI (iMRI) alone.

METHODS: Frame-based DBS surgeries of 46 targets performed from 2/8/07 to 4/29/08 in 26 patients using immediate post-implantation iMRI for target localization were compared to frame-based immediate post-implantation iCT fused with a recent 3T brain MRI for DBS localization of 50 targets performed from 8/13/08 to 2/18/10 in 26 patients. Pre and post-operative mid AC-PC line coordinates & XYZ coordinates for preoperatively calculated DBS targets (intended target) and for the permanent DBS lead-tips were determined. The differences between pre-operative DBS-target and post-operative permanent DBS lead-tip coordinates based on post-implantation intra-operative MRI for the MRI-alone group and based on post-implantation intraoperative CT fused to recent pre-operative MRI in the CT-MRI group were measured. T-test and Yuen test were used for comparison.