Intraoperative visualisation of functional structures facilitates safe frameless stereotactic biopsy in the motor eloquent regions of the brain.

BACKGROUND: For stereotactic brain biopsy involving motor eloquent regions, the surgical objective is to enhance diagnostic yield and preserve neurological function. To achieve this aim, we implemented functional neuro-navigation and intraoperative magnetic resonance imaging (iMRI) into the biopsy procedure. The impact of this integrated technique on the surgical outcome and postoperative neurological function was investigated and evaluated. METHOD: Thirty nine patients with lesions involving motor eloquent structures underwent frameless stereotactic biopsy assisted by functional neuro-navigation and iMRI. Intraoperative visualisation was realised by integrating anatomical and functional information into a navigation framework to improve biopsy trajectories and preserve eloquent structures. iMRI was conducted to guarantee the biopsy accuracy and detect intraoperative complications. The perioperative change of motor function and biopsy error before and after iMRI were recorded, and the role of functional information in trajectory selection and the relationship between the distance from sampling site to nearby eloquent structures and the neurological deterioration were further analyzed. RESULTS: Functional neuro-navigation helped modify the original trajectories and sampling sites in 35.90% (16/39) of cases to avoid the damage of eloquent structures. Even though all the lesions were high-risk of causing neurological deficits, no significant difference was found between preoperative and postoperative muscle strength. After data analysis, 3mm was supposed to be the safe distance for avoiding transient neurological deterioration. During surgery, the use of iMRI significantly reduced the biopsy errors (p = 0.042) and potentially increased the diagnostic yield from 84.62% (33/39) to 94.87% (37/39). Moreover, iMRI detected intraoperative haemorrhage in 5.13% (2/39) of patients, all of them benefited from the intraoperative strategies based on iMRI findings. CONCLUSIONS: Intraoperative visualisation of functional structures could be a feasible, safe and effective technique. Combined with intraoperative high-field MRI, it contributed to enhance the biopsy accuracy and lower neurological complications in stereotactic brain biopsy involving motor eloquent areas.

Facial and Cochlear Nerve Complications following Microsurgical Resection of Vestibular Schwannomas in a Series of 221 Cases.

BACKGROUND: Despite improvements in microsurgical technique and the use of intraoperative electrophysiological monitoring, the potential for facial and cochlear nerve injury remains a possibility in the resection of vestibular schwannomas (VS). We reviewed a series of 221 cases of VS resected via a retrosigmoid approach at our institution from October 2008 to April 2014 and determined the incidence of postoperative facial and cochlear deficits. MATERIAL AND METHODS: A total of 221 patients - 105 (47.5%) male and 116 (52.5%) female - with a mean age of 46.1 years (range 29-73 years), with VS ≥3 cm (n=183, 82.8%) and <3 cm (n=38, 17.2%) underwent surgical resection via a retrosigmoid approach and were evaluated for postoperative facial and cochlear nerve deficits. RESULTS: Near-total resection (>95% removal) was achieved in 199 cases (90%) and subtotal resection (>90% removal) in 22 cases (10%). At 6 month follow-up, House-Brackmann grades I-III were observed in 183 cases (82.8%), grade IV in 16 cases (7.2%), and grade V in 22 cases (10%). Of the 10 patients that had preoperative functional hearing, 3 (33%) retained hearing postoperatively. Cerebrospinal fluid leakage occurred in 6 patients (2.7%), lower cranial nerve palsies in 9 patients (4.1%), and intracranial hematomas 3 cases (1.4%). CONCLUSIONS: The observed incidence of persistent postoperative nerve deficits is very low. Meticulous microsurgical dissection of and around the facial and cochlear nerves with the aid of intraoperative electrophysiological nerve monitoring in the retrosigmoid approach allows for near-total resection of medium and large VS with the possibility of preservation of facial and cochlear nerve function.

[High-field intraoperative magnetic resonance imaging suite with neuronavigation system: implementation and preliminary experience in the pituitary adenoma operation with transsphenoidal approach].

OBJECTIVES: To review the preliminary clinical experience with high-field-strength intraoperative magnetic resonance imaging (iMRI) suite with neuronavigation system in the pituitary adenoma operation with transsphenoidal approach. METHODS: From March 2009 to December 2010, 31 patients [range, 29 - 76 years, mean age (47 ± 11) years]of pituitary adenoma were operated with transsphenoidal approach and intraoperatively with a movable 1.5 T high-field-strength iMRI suite in combination with neuronavigation system. Tumor size was 1.8 - 7.3 cm, mean (3.5 ± 1.2) cm. Twenty-five cases were non-functional pituitary adenoma, 4 cases were prolactin-secreting pituitary adenoma, 2 cases were growth hormone-secreting pituitary adenoma. Thirty patients' resection with transnasal transsphenoidal approach were performed, one patient with transoral transsphenoidal approach was performed. RESULTS: In 12 cases of 30 patients who planed to totally remove tumor, iMRI had revealed residual lesions and resulted in the change of the surgical strategy, 2 invasive cavernous sinus cases no further resection of the tumor because of internal carotid artery encasement, the other 10 cases resected further, eventually. Finally, 8 cases were totally removed. The ratio of total removal tumor was enhanced to 86.7% (26/30) from 60.0% (18/30). There was no perioperative mortality. CONCLUSIONS: High-field-strength iMRI suite with neuronavigation system provides valuable information of tumor resection that allows intraoperative modification of the surgical strategy. It could be very helpful to maximize the resection of the pituitary adenoma and minimize the injury to neurological function.

[Implementation and preliminary experience of high-field intraoperative magnetic resonance imaging in the endoscopic chordoma operation with transsphenoidal or transoral approach].

OBJECTIVE: To review the preliminary clinical experience with high-field-strength intra-operative magnetic resonance imaging (iMRI) in the endoscopic chordoma operation with transsphenoidal or transoral approach. METHODS: From January 2009 to December 2010, 23 patients [range, 29 - 64 years, mean age (42 ± 3) years] of chordoma were operated with endoscopic transsphenoidal or transoral approach and examined intraoperatively with a movable 1.5 T iMRI magnet. Tumor size range was 2.0 - 5.7 cm, mean (3.5 ± 0.8) cm. A navigation system based on iMRI was used in 20 cases. RESULTS: iMRI scan were performed in each operation from 1 time to 5 times. Neuronavigation system were used in 20 operations and the data renewed in 12 cases by the information from iMRI. In 15 of 23 patients, iMRI had revealed residual lesions and resulted in 12 cases further treatment, eventually, 9 tumors were totally removed and 3 tumors were further removed. The ratio of total removal tumor was enhanced to 73.9% (17/23) from 34.8% (8/23). Among 15 cases of partial chordoma removal detected by scanning in operation, 9 were huge chordoma. The residual of huge chordoma detected by scanning in operation was 9/11, and other chordoma contributed to 6/12. There were no iMRI related safety issue or accident recorded in this study. CONCLUSIONS: High-field-strength iMRI provide high-quality images of tumor resection that allows intraoperative modification of the surgical strategy. Combined with the navigation system, iMRI is helpful to maximize the resection of the chordoma and benefit for the safety of endoscopic operation.

Image-guided endoscopic surgery for spontaneous supratentorial intracerebral hematoma.

OBJECTIVE Endoscopic removal of intracerebral hematomas is becoming increasingly common, but there is no standard technique. The authors explored the use of a simple image-guided endoscopic method for removal of spontaneous supratentorial hematomas. METHODS Virtual reality technology based on a hospital picture archiving and communications systems (PACS) was used in 3D hematoma visualization and surgical planning. Augmented reality based on an Android smartphone app, Sina neurosurgical assist, allowed a projection of the hematoma to be seen on the patient's scalp to facilitate selection of the best trajectory to the center of the hematoma. A obturator and transparent sheath were used to establish a working channel, and an endoscope and a metal suction apparatus were used to remove the hematoma. RESULTS A total of 25 patients were included in the study, including 18 with putamen hemorrhages and 7 with lobar cerebral hemorrhages. Virtual reality combined with augmented reality helped in achieving the desired position with the obturator and sheath. The median time from the initial surgical incision to completion of closure was 50 minutes (range 40-70 minutes). The actual endoscopic operating time was 30 (range 15-50) minutes. The median blood loss was 80 (range 40-150) ml. No patient experienced postoperative rebleeding. The average hematoma evacuation rate was 97%. The mean (± SD) preoperative Glasgow Coma Scale (GCS) score was 6.7 ± 3.2; 1 week after hematoma evacuation the mean GCS score had improved to 11.9 ± 3.1 (p < 0.01). CONCLUSIONS Virtual reality using hospital PACS and augmented reality with a smartphone app helped precisely localize hematomas and plan the appropriate endoscopic approach. A transparent sheath helped establish a surgical channel, and an endoscope enabled observation of the hematoma's location to achieve satisfactory hematoma removal.