Ten years' experience with intraoperative MRI-assisted transsphenoidal pituitary surgery.

OBJECTIVE: Many innovations have been introduced into pituitary surgery in the quest to maximize the extent of tumor resection. Because of the deep and narrow surgical corridor as well as the heterogeneity of confronted pathologies, anatomical orientation and identification of the target tissue can become difficult. Intraoperative MRI (iMRI) may have the potential to increase extent of resection (EOR) in transsphenoidal pituitary surgery. Furthermore, it may simplify anatomical orientation and risk assessment in difficult cases. Here, the authors evaluated the additional value of iMRI for the resection of pituitary adenomas performed in the past 10 years in their department. METHODS: They performed a retrospective single-center analysis of patients treated for pituitary adenoma in their department after the introduction of iMRI between 2008 and 2018. Of 495 transsphenoidal approaches, 300 consecutive MRI-assisted surgeries for pituitary adenomas encompassing 294 patients were selected for further analysis. Microscopic, endoscopic, or endoscope-assisted microscopic transsphenoidal approaches were distinguished. EOR as well as additional resection following iMRI was evaluated via detailed volumetric analysis. Patients were stratified according to the Knosp adenoma classification. Furthermore, demographic data, clinical symptoms, endocrine outcome, and complications were evaluated. Univariable and multivariable Cox regression analyses of progression-free survival (PFS) were performed. RESULTS: Pituitary adenomas classified as Knosp grades 0-2 were found in 60.3% of cases (n = 181). The most common tumors were nonfunctioning adenomas (75%). Continued resection following iMRI significantly increased EOR (7.5%, p < 0.001) and the proportion of gross-total resections (GTRs) in transsphenoidal pituitary surgery (54% vs 68.3%, p < 0.001). Additional resection after iMRI was performed in 37% of cases. Only in the subgroup of patients with Knosp grades 0-2 adenomas treated with the microsurgical technique was additional resection significantly more common than in the endoscopic group (p = 0.039). Residual tumor volume, Knosp grade, and age were confirmed as independent predictors of PFS (p < 0.001, p = 0.021, and p = 0.029, respectively) in a multivariable Cox regression analysis. Improvement of visual field deficits was documented in 78.6% of patients whose optic apparatus had been affected preoperatively. Revision surgery was done in 7.3% of cases; in 5.6% of cases, it was performed for cerebrospinal fluid fistula. CONCLUSIONS: In this series, iMRI led to the detection of a resectable tumor remnant in a high proportion of patients, resulting in a greater EOR and higher proportion of GTRs after continued resection in microsurgical and endoscopic transsphenoidal resection of pituitary adenomas. The volume of residual tumor was the most important predictor of PFS. Given the study data, the authors postulated that every bit of removed tumor serves the patient and increases their chances of a favorable outcome.

Intraoperative MRI in transsphenoidal resection of invasive pituitary macroadenomas.

The use of intraoperative MRI (iMRI) increases extent of resection in transsphenoidal pituitary surgery. Microsurgical and endoscopic techniques have been established as equal and standard surgical methods. The object of the current study was to evaluate the additional value of iMRI for resection of invasive pituitary adenomas. We conducted a retrospective monocenter study of all consecutive patients treated with invasive pituitary adenomas graded as Knosp III-IV at our department after the introduction of iMRI in 2008. Out of 315 transsphenoidal surgeries for pituitary adenomas, 111 met the criteria for analysis. Patients treated with endoscopic or microsurgical technique were included. iMRI was performed at surgeons' discretion, when maximal safe resection was assumed. Detailed volumetric tumor analysis using semiautomatic segmentation software (Brainlab Elements) before surgery, during surgery, and after surgery was performed. Additionally, demographic data, additional resection, endocrinological outcome as well as complications were evaluated. Postoperative tumor volume as measured in the follow-up MRI 3 months after surgery was significantly lower compared with intraoperative tumor volume (p < 0.001). The difference was statistically significant for both surgical techniques (p < 0.001). No significant difference was found between both techniques in intraoperative and postoperative tumor volume (p = 0.395 and p = 0.329 respectively). Additional tumor resection was performed in 56 cases (50.5%). We found no significant difference between microsurgical and endoscopic techniques regarding additional resection after iMRI (p = 0.512). New diagnosed permanent diabetes insipidus was found in 10 patients (10.5%, 10/95). New hypopituitarism was seen in 22.1% (21/95) cases and according to multivariate logistic regression was significantly associated with microsurgical technique (p = 0.035). Visual improvement was achieved in 76.8% (N = 53/69, p < 0.001) of patients with visual impairment before surgery. Revision surgery as the consequence of cerebrospinal fistula was performed in eight cases (7.2%). Meningitis was documented in three patients (2.7%). One patient died as a consequence of intraoperative vascular injury. Intraoperative MRI after maximal safe resection significantly improves the overall extent of resection in invasive pituitary adenomas independent of the surgical technique employed. Simultaneously, iMRI-assisted transsphenoidal surgery results in excellent visual recovery with low-risk profile for surgical complications for both endoscopic as well as microsurgical technique. Endoscopic technique might be related to the lower incidence of new hypopituitarism after surgery.

The impact of SARS-Covid-19 pandemic on peripheral nerve surgery - A single centre report.

OBJECTIVE: SARS-Cov-19 pandemic totally changed daily routine work in German hospitals. As hospital capacity was reduced, many surgeries were postponed or even cancelled. On March 25th 2020 the German Society of Neurosurgery (DGNC) published a statement in which urgent non-elective surgeries were defined for each neurosurgical domain, whereas elective interventions were deferred. The present work examines the impact of these Covid strategies focusing on patients with peripheral lesions who were conducted to our department during this period of time. METHODS: All patients who underwent any peripheral nerve surgery at our department from January 2018 until December 2022, were included. The complete range of surgeries including peripheral nerve lesions was examined encompassing compression syndromes, traumatic lesions of brachial plexus, traumatic lesions and tumors of single peripheral nerves. The numbers of surgical procedures were compared before, during and after pandemic. Pearson correlation coefficient was analysed. RESULTS: From 2018 to 2022 the total number of surgical procedures involving peripheral nerves included 2422 procedures. Compression syndromes made up the largest proportion (1433 operations, 59%), followed by peripheral nerve lesions (445 operations, 18%), peripheral nerve tumors (344 operations, 14%) and lesions of the brachial plexus (142 operations, 6%). The average was 40,5 interventions per month, the range was 7-63. Two declines in the number of peripheral nerve surgeries were noted during this period. The first was in April and May 2020 with an average drop of 65% and 41% respectively. In these months the average number of operations was 37. The second decrease was from October 2021 until January 2022, where number of surgeries was reduced by 16%, 36%, 83% and 18% with an average number of 50 operations. Both declines showed a significant and strong correlation with the lower number of compression syndrome treatments (r = 0.952, p < 0.001 and r = 0.968, p < 0.001), while no drop and no significant correlation was found in the treatment of traumatic peripheral nerve injuries (p = 0.769, r = 0.095 and p = 0.243, r = 0.366) and traumatic brachial plexus injuries (p = 0.787, r = 0.088 and p = 0.780, r = 0.09). A weak significant correlation was seen in the treatment numbers of peripheral nerve tumors (p = 0.017, r = 0.672 and p = 0.015, r = 0.67). CONCLUSION: Covid-19 pandemic lead to a significant decrease in the number of nerve decompressions, since, according to the German Society of Neurosurgery, those were considered as elective surgeries.

Combined stent retriever angioplasty and continuous intra-arterial nimodipine infusion as salvage therapy for cerebral vasospasm and delayed cerebral ischemia after subarachnoid hemorrhage: illustrative case.

BACKGROUND: Delayed cerebral ischemia (DCI) and cerebral vasospasm (CV) are severe complications of spontaneous subarachnoid hemorrhage (SAH) contributing to an inferior outcome. Rescue therapies include intra-arterial balloon angioplasty and repetitive and finally continuous intra-arterial nimodipine infusion. OBSERVATIONS: In the presented case, a young female patient with fulminant refractory DCI and CV, despite induced hypertension and nimodipine application, was treated with three-vessel continuous intra-arterial infusion and additional repetitive angioplasty of the basilar and middle cerebral arteries using a stent retriever, leading to a good clinical outcome. Additional stent retriever dilatation to continuous intra-arterial nimodipine application in three vessel territories may represent a further escalation step in the rescue therapy for severe CV and DCI after SAH. Montreal Cognitive Assessment and SF-36 testing showed satisfactory results 3 months after initial treatment with intra-arterial nimodipine catheters in three vessel territory circulations and additional stent retriever vasodilation of severe CV. LESSONS: We report a unique rescue strategy involving implantation of an additional intra-arterial catheter into the vertebral artery and repetitive stent retriever dilatations of the middle cerebral and basilar arteries as an extra therapy for continuous intra-arterial nimodipine vaspospasmolytic therapy in three vessel territories, resulting in a very good clinical outcome.

The Benefit of Intraoperative Magnetic Resonance Imaging in Endoscopic and Microscopic Transsphenoidal Resection of Recurrent Pituitary Adenomas.

The surgical treatment of recurrent adenomas can be challenging. Intraoperative magnetic resonance imaging (iMRI) can improve the orientation and increase the safe extent of resection. We conducted a quantitative and qualitative retrospective analysis of recurrent adenomas treated by endoscopic or microscopic iMRI-assisted transsphenoidal surgery. A total number of 59 resections were selected. Detailed volumetric measurements, tumor characteristics, and MRI features of intraoperative remnants were evaluated. Intraoperative MRI increased the gross total resection (GTR) rate from 33.9% to 49.2%. Common locations of tumor remnants after iMRI were the clivus, the wall of the cavernous sinus or the perforation of the diaphragm. Increasing tumor volume and the microscopic technique were significantly associated with further resection after iMRI in the univariate analysis (p = 0.004, OR 1.6; p = 0.009, OR 4.4). Only the increasing tumor volume was an independent predictor for further resection (p = 0.007, OR 1.5). A significantly higher proportion of GTRs was achieved with the endoscopic technique (p = 0.001). Patients with a large recurrent pituitary adenoma who underwent microscopic transsphenoidal resection were the most likely to benefit from iMRI regarding the extent of resection. Occult invasions of the cavernous sinus and/or the clivus were the most common findings leading to further resection of tumor remnants after iMRI.

Clinical outcome after decompression of intraneural peroneal ganglion cyst and its morphologic correlation to postoperative nerve ultrasound.

OBJECTIVE: Intraneural ganglion cysts are rare and benign mucinous lesions that affect peripheral nerves, most frequently the common peroneal nerve (CPN). The precise pathophysiological mechanisms of intraneural ganglion cyst development remain unclear. A well-established theory suggests the spread of mucinous fluid along the articular branch of the peroneal nerve as the underlying mechanism. Clinical outcome following decompression of intraneural ganglion cysts has been demonstrated to be excellent. The aim of this study was to evaluate the correlation between clinical outcome and ultrasound-detected morphological nerve features following decompression of intraneural ganglion cysts of the CPN. METHODS: Data were retrospectively analyzed from 20 patients who underwent common peroneal nerve ganglion cyst decompression surgery at the Universität Ulm/Günzburg Neurosurgery Department between October 2003 and October 2017. Postoperative clinical outcome was evaluated by assessment of the muscular strength of the anterior tibial muscle, the extensor hallucis longus muscle, and the peroneus muscle according to the Medical Research Council grading system. Hypesthesia was measured by sensation testing. In all patients, postoperative morphological assessment of the peroneal nerve was conducted between October 2016 and October 2017 using the iU22 Philips Medical ultrasound system at the last routine follow-up appointment. Finally, the correlations between morphological changes in nerve ultrasound and postoperative clinical outcomes were evaluated. RESULTS: During the postoperative ultrasound scan an intraneural hypoechogenic ring structure located at the medial side of the peroneal nerve was detected in 15 (75%) of 20 patients, 14 of whom demonstrated an improvement in motor function. A regular intraneural fasicular structure was identified in 3 patients (15%), who also reported recovery. In 1 patient, a recurrent cyst was detected, and 1 patient showed intraneural fibrosis for which recovery did not occur in the year following the procedure. Two patients (10%) developed neuropathic pain that could not be explained by nerve ultrasound findings. CONCLUSIONS: The results of this study demonstrate significant recovery from preoperative weakness after decompression of intraneural ganglion cysts of the CPN. A favorable clinical outcome was highly correlated with an intraneural hypoechogenic ring-shaped structure on the medial side of the CPN identified during a follow-up postoperative ultrasound scan. These study results indicate the potential benefit of ultrasound scanning as a prognostic tool following decompression procedures for intraneural ganglion cysts of the CPN.

Is MGMT promoter methylation to be considered in the decision making for recurrent surgery in glioblastoma patients?

OBJECTIVES: At present, there is no standard therapy approved for recurrent glioblastoma (rGB). In particular, the counselling of patients with an unmethylated O6-methylguanine-DNA methyltransferase (MGMT) promoter GB remains a challenge. Our aim was to compare the overall survival (OS) and progression free survival (PFS) in patients treated surgically and non-surgically at the time of GB recurrence. This was evaluated with particular reference to the impact of recurrent surgery for patients with unmethylated MGMT promoter rGB. PATIENTS AND METHODS: The clinical and radiological data from 127 consecutive cases of rGB was retrospectively identified and evaluated. The PFS and OS from cohorts of surgically and non-surgically treated patients at time of GB recurrence were compared using Kaplan Meier estimations and Log-Rank tests. Multivariate Cox regression analysis included the major influencing variables (surgical resection, MGMT promoter methylation status, Karnofsky performance scale (KPS), age, eloquent tumor location) to analyze the survival benefit. Subgroup analysis of cases depending on the MGMT promoter methylation status was performed. RESULTS: Multiple Cox regression analysis revealed inferior OS (p = 0.029, OR = 1.731, CI 95% 1.059-2.829) of patients treated non-surgically (14 vs. 31 months). MGMT promoter methylation and age were related to longer OS (p < 0.001, OR 2.683, CI 95% 1.631-4.414 and p = 0.009, OR = 1.029, CI95% 1.007-0.052 respectively). Gross total resection (GTR) in comparison to subtotal resection (STR) lead to a median OS of 39 months vs. 22 months and a PFS of seven vs. four months respectively. In the subgroup of cases with unmethylated MGMT promoter rGB, those who underwent GTR survived significantly longer (OS: 31 months) than patients who underwent STR (OS: 15 months, p = 0.024). PFS was six vs. four months after GTR and STR respectively. CONCLUSION: Surgical management for recurrent glioblastoma appears to be a safe procedure which results in longer OS in comparison to non-surgical management. GTR may be of particular benefit to patients with unmethylated MGMT promoter rGB.

The Value of Intraoperative Magnetic Resonance Imaging in Endoscopic and Microsurgical Transsphenoidal Pituitary Adenoma Resection.

BACKGROUND: The routine use of intraoperative magnetic resonance imaging (iMRI) helps to achieve gross total resection in transsphenoidal pituitary surgery. We compared the added value of iMRI for extent of resection in endoscopic versus microsurgical transsphenoidal adenomectomy. METHODS: A total of 96 patients with pituitary adenoma were included. Twenty-eight consecutive patients underwent endoscopic transsphenoidal tumor resection. For comparison, we used a historic cohort of 68 consecutive patients treated microsurgically. We evaluated the additional resection after conducting iMRI using intraoperative and late postoperative volumetric tumor analysis 3 months after surgery. Demographic data, clinical symptoms, and complications as well as pituitary function were evaluated. RESULTS: We found significantly fewer additional resections after conducting iMRI in the endoscopic group (P = 0.042). The difference was even more profound in Knosp grade 0-2 adenomas (P = 0.029). There was no significant difference in Knosp grade 3-4 adenomas (P = 0.520). The endoscopic approach was associated with smaller intraoperative tumor volume (P = 0.023). No significant difference was found between both techniques in postoperative tumor volume (P = 0.228). Satisfactory results of pituitary function were significantly more often associated with an endoscopic approach in the multiple regression analysis (P = 0.007; odds ratio, 17.614; confidence interval 95%, 2.164-143.396). CONCLUSIONS: With the endoscopic approach, significantly more tumor volume reduction was achieved before conducting iMRI, decreasing the need for further resection. This finding was even more pronounced in adenomas graded Knosp 0-2. In the case of extensive and invasive adenomas with infiltration of cavernous sinus and suprasellar or parasellar extension, additional tumor resection and increase in the extent of resection was achieved with iMRI in both groups. The endoscopic approach seems to result in better endocrine outcomes, especially in Knosp grade 0-2 pituitary adenomas.