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Objective: The oculomotor cistern (OMC) is a meningeal cuff filled with CSF that contains the oculomotor nerve (cranial nerve [CN] III) at the level of the lateral wall of the cavernous sinus. Only a few studies have investigated the involvement of the OMC by pituitary adenomas (pituitary neuroendocrine tumors [PitNETs]), mainly with relatively small case series. The aim of this study was to perform a histomorphological description of the OMC and systematically analyze its involvement by PitNETs from radiological, clinical, and surgical perspectives., Methods: Ten hemisellae from formalin-fixed specimens were studied with 3-µm sections. Digital image analysis software was used for morphological and quantitative assessments. Clinical, radiological, surgical, and histological data of patients undergoing endoscopic transsphenoidal surgery for PitNETs at the University of Brescia, Italy, between 2014 and 2021 were recorded. OMC involvement was graded as not compressed, compressed, and invaded. The same surgical team operated on all patients., Results: The OMC had an elliptical shape with an average area of 3.1 mm2 and a length of 5.5 mm. No cisternal points of weakness were recognized in the histomorphological study. Of 315 patients, 246 had complete data: apoplexy and CN III palsy were documented in 6.9% and 8.5%, respectively. OMC compression and invasion were recorded in 106 (43.1%) and 23 (9.3%) patients. Significant associations between OMC involvement and PitNET dimensions (p < 0.001), Knosp grade (p < 0.001), preoperative oculomotor palsy (p < 0.001), Ki-67 percentage (p = 0.009), and recurrence/progression of residual tumor (p = 0.008) were found. A new postoperative CN III palsy was evident in 2%: transient in 4 cases, and persistent in 1 patient treated for a recurrent PitNET who experienced a local infection complication. Preoperative CN III palsy improved in 10 cases., Conclusions: Significant OMC involvement by PitNETs might be underrecognized, but it can be treated using the endoscopic transsphenoidal approach, and it affects patient outcomes.

Objective: Dysphagia is a significant complication in fourth ventricle surgery. Corticobulbar motor evoked potentials (CB-MEPs) of the lower cranial nerves may provide real-time information possibly correlating with postoperative swallowing dysfunction, and the vagus nerves may prove ideal for this purpose. However, the literature is heterogeneous, non-systematic, and inconclusive on this topic. The object of this retrospective study was to evaluate the correlation between CB-MEPs of the vagus nerve and postoperative worsening or new-onset swallowing deficits in intraaxial fourth ventricle surgery., Methods: In 21 consecutive patients undergoing surgery for fourth ventricle intraaxial tumors between February 2018 and October 2022, endotracheal tubes with two applied electrodes contacting the vocal cords were used to record vagus nerve MEPs including values at baseline, the end of surgery, and the minimum value during the operation. From the mean value of right and left vagus nerve MEP amplitudes, the minimum-to-baseline amplitude ratio (MBR) and final-to-baseline amplitude ratio (FBR) were calculated. These indexes were correlated with postoperative swallowing function., Results: Given their clinical significance, receiver operating characteristic curves were obtained to evaluate the performance of these indexes in predicting postoperative swallowing function. The area under the curve (AUC) was 0.850 (p < 0.001) and the best cutoff for FBR was 67.55% for the worsening of swallowing in the postoperative period. The AUC was 0.750 (p = 0.026) and the best cutoff was 46.37% in MBR for the absence of a swallowing disorder at the late follow-up., Conclusions: This study confirmed that vagus nerve MEPs are reliable predictors of postoperative swallowing function in fourth ventricle surgery and can be feasibly used as an intraoperative monitoring technique.

The authors report on the first case of the intraventricular administration of tigecycline described in the Western literature. A 22-year-old man developed cerebrospinal fluid infection from an extremely drug-resistant strain of Acinetobacter baumannii as a complication of endoscopic transsphenoidal surgery for the removal of a giant pituitary adenoma. The patient was safely and successfully treated with the prolonged intraventricular administration of tigecycline. Here, the authors provide the schedule details that can be invaluable in treating meningitis from extremely drug-resistant bacterial strains. Intraventricular tigecycline can be a valuable tool against multidrug-resistant central nervous system infections.

OBJECT Only a few published studies of the surgical treatment of benign peripheral nerve sheath tumors (BPNSTs), malignant peripheral nerve sheath tumors (MPNSTs), and peripheral non-neural sheath tumors (PNNSTs) have analyzed the results and possible prognostic factors using multivariate analysis. The authors report on their surgical series of cases of BPNSTs, MPNSTs, and PNNSTs with long-term follow-up and analyze the role of selected factors with respect to the prognosis and risk of recurrence of these tumors using multivariate analysis. They also review the pertinent literature and discuss their results in its context. METHODS The authors retrospectively reviewed data from cases involving patients who underwent resection of a peripheral nerve tumor between January 1983 and December 2013 at their institution. Of a total of 200 patients, 150 patients (with 173 surgically treated tumors) had adequate follow-up data available for analysis. Pain was assessed using a visual analog scale (VAS), and motor and sensory function were assessed by means of the Louisiana State University grading system. They also analyzed the relationship between tumor recurrence and patient sex, patient age, diagnosis of neurofibromatosis (NF), tumor histopathology, tumor size, tumor location, and extent of resection (subtotal vs gross-total resection), using univariate and multivariate analyses. RESULTS There was a statistically significant improvement in the mean VAS pain score (preoperative 3.96 ± 2.41 vs postoperative 0.95 ± 1.6, p = 0.0001). Motor strength and sensory function were significantly improved after resection of tumors involving the brachial plexus (p = 0.0457 and p = 0.0043, respectively), tumors involving the upper limb (p = 0.0016 and p = 0.0016, respectively), BPNSTs (p = 0.0011 and p < 0.0001, respectively), and tumors with dimensions less than 5 cm (motor strength: p = 0.0187 and p = 0.0021 for ≤ 3 cm and 3-5 cm tumors, respectively; sensory function: p = 0.0003 and p = 0.0001 for ≤ 3 cm and 3-5 cm tumors, respectively). Sensory function showed a statistically significant improvement also in patients who had undergone resection of tumors involving the lower limb (p = 0.0118). Total resection was associated with statistically significant improvement of motor strength (p = 0.0251) and sensory function (p < 0.0001). In univariate analysis, a history of NF (p = 0.0034), a diagnosis of MPNST or PNNST (p < 0.0001), and subtotal resection (p = 0.0042) were associated with higher risk of tumor recurrence. In multivariate analysis (logistic regression analysis), a history of NF (OR 9.28%, 95% CI 1.62-52.94, p = 0.0121) and a diagnosis of MPNST (OR 0.03%, 95% CI 0.002-0.429, p = 0.0098) or PNNST (OR 0.081%, 95% CI 0.013-0.509, p = 0.0077) emerged as independent prognostic factors for tumor recurrence. CONCLUSIONS A total resection should be attempted in all cases of peripheral nervous system tumors (irrespective of the supposed diagnosis and tumor dimensions) because it is associated with better prognosis in term of functional outcome and overall survival. Moreover, a total resection predicts a lower risk of tumor recurrence. Patients with a history of NF and tumors with malignant histology remain a challenge both for neurosurgeons and oncologists due to higher recurrence rates and the lack of standardized adjuvant therapies.

Object: Communicating hydrocephalus is an uncommon complication in patients treated for glioblastoma multiforme (GBM). Its pathogenesis remains unclear. The authors evaluated the clinical and radiological factors associated with the onset of communicating hydrocephalus and the impact of ventriculoperitoneal (VP) shunt surgery on the outcome of these patients., Methods: One hundred twenty-four patients harboring GBM, who had undergone craniotomy for tumor resection and adjuvant radiochemotherapy, were retrospectively assessed. Seven of them developed communicating hydrocephalus and were treated with VP shunt surgery. Clinical and radiological estimates included Karnofsky Performance Scale (KPS) score, previous surgery, overall survival (OS), CSF pressure and components, tumor location, and leptomeningeal dissemination., Results: All 7 patients who developed communicating hydrocephalus had undergone at least 2 craniotomies for tumor resection before the onset of hydrocephalus (p = 0.0006; Fisher exact test). Six cases showed high levels of CSF proteins. There was a highly significant relationship between ventricular opening at surgery for tumor recurrence and onset of hydrocephalus (p = 0.0002; Fisher exact test). In these patients, VP shunt surgery was followed by a significant improvement of KPS score (p = 0.0180; Wilcoxon signed-rank test). The median OS after VP shunt insertion was 5 ± 2.9 months., Conclusions: Ventricular opening after radiochemotherapy and high CSF protein levels are significant predictors of communicating hydrocephalus in patients with GBM. The VP shunt surgery improves quality of life in these patients.

Chordoid meningioma is a rare meningothelial tumor characterized by chordoma-like histological features with lymphoplasmacellular infiltration. This tumor is often seen in children, but not in adults, with a systemic inflammatory syndrome (iron-resistant microcytic anemia and/or dysgammaglobulinemia) and very rarely with a persistent moderate hyperthermia. In the present report the authors describe a temporal chordoid meningioma in a 30-year-old woman who presented with fever, headache, and a serological inflammatory syndrome. The clinical symptomatology, chiefly the fever, disappeared immediately after removal of the tumor. To the authors' knowledge, only one similar patient with such clinical presentation and response to surgery has been mentioned in the literature. Interestingly, at immunohistochemical examination, the neoplasm showed focal positivity for the pyrogenic cytokine interleukin-6. The capacity of the tumor to produce this pyrogenic cytokine could explain both the patient's clinical presentation and her response to the surgical management.

Although the craniocervical junction is involved in a variety of conditions including trauma, neoplastic lesions, and inflammatory processes, isolated inflammatory conditions involving the occipital condyle exclusively are not known. The authors report this unusual condition in two cases. Unless the patient is of poor medical risk, excision of the lesion is the treatment of choice to decompress the neural structures.

An 18-year-old man presented with a spontaneously occurring radial nerve palsy that spared the triceps muscle. At surgery, the portion of the radial nerve located at the midarm level had an hourglass-like appearance. Under magnification, an external-internal neurolysis of the narrowed portion of the hourglass-shaped portion revealed nerve torsion. Straightening of the twisted nerve and fixation accomplished using epiperineurium-fascia stitches to avoid a new torsion resulted in complete functional recovery of the radial nerve.

The authors report the case of a young man suffering from neurofibromatosis type 2 (NF2) who harbored bilateral acoustic schwannomas and a parasellar meningioma. Neuroimaging studies performed during a 4-year follow-up period showed that the bilateral schwannomas had grown very little and at similar rates. However, after the meningioma had infiltrated the tentorium and approached the ipsilateral schwannoma at the incisura, both Schwann cell tumors started to grow rapidly, particularly the one adjacent to the meningioma, of which the percentage of annual growth rate increased by approximately a factor of 10(2). At the same time, magnetic resonance imaging showed that this tumor also changed its features. During surgery, the acoustic schwannoma was firmly adherent to both meningioma and tentorium. Histological examination revealed meningotheliomatous cells in the schwannoma adjacent to the meningioma. Antiphosphotyrosine immunoblotting of PC12 cells was compatible with the presence of an epidermal growth factor (EGF)-like molecule in the cerebrospinal fluid (CSF) of the patient. This factor was not detected in the CSF of five other NF2 patients, two of whom bore associated bilateral acoustic schwannomas and meningioma in remote locations. It is hypothesized that the meningotheliomatous cells infiltrating the schwannoma triggered an autocrine/paracrine growth-stimulatory mechanism that involved an EGF-like factor.

The superior cervical ganglion (SCG) has been grafted to the brain of adult rats in an attempt to reverse the parkinsonian syndrome that follows destruction of central dopamine systems. However, the main limitation to this approach is the massive cell death that occurs in the grafted SCG after direct transplantation into the brain. In adult rats, 6-hydroxydopamine (6-OHDA) was stereotactically injected into the right substantia nigra (SN). One month later, dopamine denervation was assessed using the apomorphine-induced rotational test. In rats with a positive test, an autologous peripheral nerve (PN) graft was tunneled from the right cervical region to the ipsilateral parietal cortex. One end of PN graft was sutured to the transected postganglionic branch of the SCG and the other end was inserted into a surgically created cortical cavity. The apomorphine test was repeated at 3 days and again at 1, 3, and 5 months after surgery. The brain, SCG, and PN graft were studied under light and electron microscopy and with the tyrosine hydroxylase immunohistochemical and horseradish peroxidase tracing methods. Three days after grafting, there were no significant differences on the apomorphine test as compared to the preoperative test. Conversely, 1,3, and 5 months after grafting, the number of rotations was reduced by 69% (+/-20.2), 66.6% (+/-17.1), and 72.5% (+/-11.3), respectively. Control rats that received a free PN graft to the brain and underwent section of the postganglionic branch of the SCG did not show significant changes on the apomorphine test after surgery. Histological examination revealed that the PN graft was mostly reinnervated by amyelinic axons of small caliber. Approximately 40% of the SCG neuronal population that normally projects to the postganglionic branch survived axotomy and regenerated the transected axons into the PN graft. Axons arising from the SCG elongated the whole length of the graft, crossed the graft-brain interface and extended into brain regions adjacent to the denervated striatum up to 2037 micrometer from the graft insertion site. This work shows that the ingrowth of catecholamine-regenerating axons from the SCG to dopamine-depleted brain parenchyma significantly reduces behavioral abnormalities in hemiparkinsonian rats. This effect cannot be ascribed either to the brain cavitation or to the PN tissue placement in the brain.

In adult guinea pigs, the oculomotor nerve was sectioned proximally (at the tentorial edge) or more distally (at the orbital fissure) and immediately repaired by reapproximation. During a 24-week postoperative period, extrinsic eye motility was assessed by analyzing the vestibulo-ocular reflexes. The regenerated oculomotor nerve was studied morphometrically on semi-thin histological sections at 16 and 24 weeks postinjury. The selectivity of muscle reinnervation was investigated by injection of both single (horseradish peroxidase) and double (fluorescent dyes) retrograde axonal tracers into the eye muscles. Following proximal repair of the oculomotor nerve, the degree of recovery of extraocular motility varied among different animals and remained stable over long-term observations. In animals with poor recovery, aberrant eye movements were always found, and the somatotopic map of the reinnervated eye muscles was greatly altered. Distortions of the central representation were also seen in those animals in which a good level of functional recovery was seen. However, in animals with good recovery, a topographic bias was re-established by about 65% of the original neuronal population, as opposed to 26% in the animals with poor recovery. Neurons located contralateral to the axotomized nucleus sprouted intra-axially and projected their axons to denervated eye muscles. The number and diameter of the regenerated axons, the number and soma diameter of the axotomized neurons, and the ratio of distal axonal branches to proximal supporting neurons were all related to the degree of functional recovery. Following repair of the oculomotor nerve at the orbital fissure, extraocular motility had recovered in all of the animals at 16 weeks without aberrant phenomena. Functional regeneration of the distally transected oculomotor nerve is thought to be the result of selective muscle reinnervation.