Posterior Fossa Surgery Research Articles

Polyethylene glycol hydrogel dural sealant may reduce incisional cerebrospinal fluid leak after posterior fossa surgery.

Incisional cerebrospinal fluid (CSF) leak remains a significant cause of morbidity, particularly after posterior fossa surgery, with ranges between 4 and 17% in most series. We aimed to determine whether the use of a new polyethylene glycol (PEG) dural sealant product (DuraSeal; Confluent Surgical, Waltham, MA) is effective at preventing incisional CSF leak after posterior fossa surgery. One hundred cases of posterior fossa surgery with the PEG dural sealant applied at the time of dural closure were prospectively observed from May 2005 to April 2006. All patients underwent posterior fossa craniotomy or craniectomy. Clinical histories were followed to document cases of incisional CSF leak, pseudomeningocele, meningitis, wound infection, and interventions required to treat a CSF leak or pseudomeningocele. A retrospective cohort of 100 patients treated in a similar fashion but with fibrin glue augmented dural closure served as controls. In the PEG group, two of 100 (2%) patients developed an incisional CSF leak postoperatively. By comparison, 10 of 100 (10%) patients in whom fibrin glue was used developed an incisional CSF leak. This difference was statistically significant, with a P value of 0.03. There were no significant differences in the rates of pseudomeningocele, meningitis, or other postoperative interventions. The application of PEG dural sealant to the closed dural edges may be effective at reducing incisional CSF leak after posterior fossa surgery.

Frontal lobe signs after posterior fossa surgery: Is hypoperfusion ignored?

Sir, Behavioral manifestations constitute major burden of patients suffering from brain tumors.[2] Cerebellar mutism syndrome, known to occur following surgery for posterior fossa tumors, is not commonly associated with behavioral symptoms. A 12-year-old boy, diagnosed with posterior fossa mass lesion underwent ventriculoperitoneal shunt followed by definitive surgery. He developed acute mutism symptoms after the surgery and presented with hyperactivity, inattention, and inappropriate social behavior in the form of soiling and urinating in public. Single-photon emission computed tomography was performed 15 days after surgery for these symptoms and it showed cerebral hypoperfusion in right frontal and thalamoganglionic regions [Figure 1]. Figure 1 Brain single-photon emission computed tomography showing moderately reduced perfusion in right inferior orbitofrontal region, right lateral temporal, right thalamic, right basal ganglia, and bilateral occipito-parietal regions (right > left) Altered speech and other manifestations after posterior fossa surgery are often secondary to edema or hypoperfusion adjacent to the surgical trauma.[4] Remote localized deficits after posterior fossa surgery are however not common, though crossed cerebello-cerebral diaschisis due to involvement of dentato-thalamo-cortical pathway has been occasionally reported.[1] Some of these atypical remote presentations were described possibly due to vascular phenomena.[3] However, extensive remote hypoperfusion as described above have not been reported much. Perfusion deficits in these atypical presentations indicate the impact of surgery on brain is more generalized than the operated area similar to the systemic nature of head injury.[4] In addition, perfusion tests may not only help to evaluate patients with atypical postoperative symptoms, but also open up therapeutic avenues as well as for prognosis. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

The Surgical Treatment of Trigeminal Neuralgia

Trigeminal Neuralgia is a clinical presentation of different diseases, defined in the last edition of the International Classification of Headache Disorders (ICHD-3) as “Classical Trigeminal Neuralgia” and “Painful Trigeminal Neuropathy”. In both groups typical and atypical clinical findings are present. They must be taking into consideration for defining a correct clinical diagnosis. In addition MRI findings and other objective signs allow to disclose the Etiology of the Trigeminal Neuralgia. The surgical treatment offers many options: open surgery in posterior fossa, neuroablative procedures on the trigeminal nerve, neuromodulation techniques on the trigeminal pathways. Open surgery and neuroablative procedures are the treatments chosen in Classical Trigeminal Neuralgia and in Painful Trigeminal Neuropathy showing pure or prevalent typical clinical findings. Instead in Painful Trigeminal Neuropathy with pure or prevalent atypical clinical findings the neuromodulation techniques are the treatments to be chosen. Looking at the Literature reports and at our own experience, techniques, results, and indications of microvascular decompression, radiofrequency thermocoagulation, glycerol rhizolysis, balloon microcompression, and sterotactic radiosurgery of the trigeminal root are reported and discussed

POGOSTOST ZRAČNE EMBOLIJE IN POOPERATIVNI ZAPLETI PRI NEVROKIRURŠKIH POSEGIH V SEDEČEM POLOŽAJU Skrajšana verzija naslova: ZRAČNA EMBOLIJA PRI NEVROKIRURŠKIH POSEGIH V SEDEČEM POLOŽAJU

Background: Posterior fossa surgery and cervical spine surgery are at risk for venous air embolism (VAE) occurrence. Mostly air emboli are small and asymptomatic, but invasion of large quantity of air in the circulation is symptomatic and potentially lethal. Transesophageal echocardiography is the most sensitive method for detection of air emboli in the heart, followed by the precordial Doppler probe, end tidal carbon dioxide monitoring (etCO2) and others.Methods: In our 14- years retrospective review we evaluated the incidence of VAE and postoperative complications in patients with posterior fossa surgery or cervical spine surgery. VAE was recognized by using Doppler probe and/or drop of etCO2. If VAE occurred, aspiration of air through the CVC was used to prevent or to minimized VAE occurrence, the surgeon was warned about the incident. VAE treatment was supportive.Results: VAE was recognized in 74 patients. Two patients after head surgery and four patients after neck surgery needed postoperative treatment in intensive care unit and controled mechanical ventilation. In six patients after head surgery and in four patients after neck surgery new neurological symptoms occurred. Two patients after head surgery died due to complications of massive VAE.Conclusions: VAE is rare, but serious complication of neurosurgery in sitting position. Preventive treatment, early detection of VAE, supportive treatment and treatment of cardiovascular complications are necessary for survival of patients with VAE.

Complications of Neurosurgery.

This article provides an overview of the major neurologic complications of common neurosurgical and endovascular procedures. Brain edema, seizures, postoperative hemorrhage, and cerebral ischemia can complicate neurosurgical procedures and produce neurologic decline. The high variability of reporting, types of operations, patient characteristics, and acuity of cases make estimating the incidence and severity of complications difficult. Overall, the complication rate of neurosurgical procedures is approximately 14%, but these are commonly systemic complications (eg, bleeding requiring transfusion, need for mechanical ventilation). In addition to intracranial hemorrhage, ischemia, and seizures after craniotomies, additional characteristic complications include hyperperfusion syndrome and cranial nerve palsies after carotid endarterectomy, cerebrospinal fluid leaks and aseptic meningitis after posterior fossa surgery, and arterial dissections or groin hematomas after endovascular procedures. Neurologic decline can be caused by a variety of causes in the postoperative period. The indication for surgery, type of surgery, and time of decline is helpful in narrowing the differential diagnosis. Brain edema, elevated intracranial pressure (ICP), seizures, intracranial hemorrhage, ischemic infarction, and cranial nerve palsies are some of the more common complications in patients that neurologists may be asked to evaluate or comanage in the postoperative setting.

Transient internuclear ophthalmoparesis associated with mutism following midline cerebellar tumour surgery in an 8-year boy

Abstract Mutism and neurobehaviour symptoms are well known features, which may occur following surgical excision of mass lesion of various histopathologies in the posterior cranial fossa, during the postoperative period. Mutism may be rarely associated with ataxia of eyelid closure and paresis of external ocular muscles. However, internuclear ophthalmoparesis is not reported in association with mutism following posterior cranial fossa surgery. We report an 8-year–boy, who developed internuclear ophthalmoparesis following suboccipital craniectomy for decompression of vermian medulloblastoma. The clinical features, aetiopathogenesis, management of transient internuclear ophthalmoparesis associated with mutism and pertinent literature is reviewed in short.

Postoperative posterior fossa syndrome: unraveling the etiology and underlying pathophysiology by using magnetic resonance imaging

Posterior fossa syndrome (PFS) is a severe, postoperative complication occurring in about 25 % of pediatric patients undergoing surgery for midline tumors in the posterior fossa. In recent years, MRI-based research elucidated the cause of PFS and shed new light on its putative pathophysiology. This review highlights the major advances arising from research of this topic. Postsurgical damage patterns in patients after posterior fossa surgery show that PFS results from bilateral surgical damage to the proximal efferent cerebellar pathways (pECPs). Surgical pECP disruption has other MRI-detectable effects that are more remote. Patients with PFS tend to develop global supratentorial cortical hypoperfusion, likely representing reversed, cerebello-cerebral diaschisis. Because this hypoperfusion is most prominent in frontal regions, cerebellar mutism may indicate a dominantly frontal lobe dysfunction, hence a peculiar form of speech apraxia. Injury to the pECP also leads to contralateral inferior olivary nucleus degeneration. When bilateral hypertrophic olivary degeneration (HOD) is observed after posterior fossa surgery, affected patients have clinical PFS. Therefore, it is suggested that bilateral HOD may be a sensitive and, in appropriate clinical settings, reliable a posteriori surrogate imaging indicator of bilateral disruption of the pECPs and consequently of PFS. Having such a "validation tool" presents new opportunities to develop better definitions for the phenotypes within the clinical spectrum of PFS. Anatomical and functional MRI techniques are suitable and valuable tools with which to detect structural changes and pathophysiological processes in the development and evolution of PFS and may be key, integral components of future clinical research endeavors.

Trigeminal neuralgia without neurovascular compression presents earlier than trigeminal neuralgia with neurovascular compression.

Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). To characterize what may be distinct patient populations, the authors examined age at onset in patients with TN with and without NVC. A retrospective review of patients undergoing posterior fossa surgery for Type I TN at Oregon Health & Science University from 2009 to 2013 was undertaken. Charts were reviewed, and imaging and operative data were collected for patients with and without NVC. Mean, median, and the empirical cumulative distribution of onset age were determined. Statistical analysis was performed using Student t-test, Wilcoxon and Kolmogorov-Smirnoff tests, and Kaplan-Meier analysis. Multivariate analysis was performed using a Cox proportional hazards model. The charts of 219 patients with TN were reviewed. There were 156 patients who underwent posterior fossa exploration and microvascular decompression or internal neurolysis: 129 patients with NVC and 27 without NVC. Mean age at symptoms onset for patients with and without NVC was 51.1 and 42.6 years, respectively. This difference (8.4 years) was significant (t-test: p = 0.007), with sufficient power to detect an effect size of 8.2 years. Median age between groups with and without NVC was 53.25 and 41.2 years, respectively (p = 0.003). Histogram analysis revealed a bimodal age at onset in patients without NVC, and cumulative distribution of age at onset revealed an earlier presentation of symptoms (p = 0.003) in patients without NVC. Chi-square analysis revealed a trend toward female predominance in patients without NVC, which was not significant (p = 0.08). Multivariate analysis revealed that age at onset was related to NVC but not sex, symptom side or distribution, or patient response to medical treatment. NVC is neither sufficient nor necessary for the development of TN. Patients with TN without NVC may represent a distinct population of younger, predominantly female patients. Further research into the pathophysiology underlying this debilitating disease is needed.

Electromagnetic navigation-guided surgery in the semi-sitting position for posterior fossa tumours: a safety and feasibility study.

Electromagnetic (EM)-guided neuronavigation is an innovative technique and a viable alternative to opto-electric navigation. We have performed a safety and feasibility study using EM-guided neuronavigation for posterior fossa surgery in the semi-sitting position in a selected subset of patients. Out of 284 patients with posterior fossa tumours operated upon over a period of 40 months, a subset of 15 patients was thought to possibly benefit from EM navigational guidance and was included in this study. There were six children and nine adults (aged between 8 and 84 years; mean age, 34.6 years) with different neoplasms in the brainstem or close to the midline. All patients had contrast-enhanced three-dimensional (3D) magnetic resonance imaging (MRI) of the head preoperatively. EM-guided navigation was used to identify and preserve the venous sinuses during craniotomy and to determine the trajectory to the lesion using various approaches. Neuronavigation accuracy was repeatedly checked for deviations measured in millimetres on screen shots during surgery before and after dural opening in the coronal (z = vertical), axial (x = mediolateral) and sagittal (y = anteroposterior) plane. Referencing of the patient in the supine position was fast and easy. There was no loss of navigation accuracy after repositioning of the patient in the semi-sitting position (mean, 2.5 mm ± 0.92 mm). Identification of the pathological structure using EM navigation was achieved in all instances. Optimal angulation of the neck was selected individually to permit a comfortable position for the surgeon with full access to the lesion avoiding over-flexion. Deviation of accuracy at the surface of the target lesion ranged between 2.5 and 5.8 mm (mean, 3.9 mm ± 1.1 mm). EM-guided neuronavigation in the semi-sitting position was safe and technically feasible. It enabled fast and accurate referencing without loss of navigation accuracy despite repositioning of the patient. In contrast to conventional opto-electric neuronavigation there were no line of sight problems.

Normobaric hyperoxia for treatment of pneumocephalus after posterior fossa surgery in the semisitting position: a prospective randomized controlled trial.

BackgroundSupratentorial pneumocephalus after posterior fossa surgery in the semisitting position may lead to decreased alertness and other symptoms. We here aimed to prove the efficacy of normobaric hyperoxia on the absorption of postoperative pneumocephalus according to a standardized treatment protocol.Methods and FindingsWe enrolled 44 patients with postoperative supratentorial pneumocephalus (> 30 ml) after posterior fossa surgery in a semisitting position. After randomisation procedure, patients received either normobaric hyperoxia at FiO2 100% over an endotracheal tube for 3 hours (treatment arm) or room air (control arm). Routine cranial CT scans were performed immediately (CT1) and 24 hours (CT2) after completion of surgery and were rated without knowledge of the therapy arm. Two co-primary endpoints were assessed: (i) mean change of pneumocephalus volume, and (ii) air resorption rate in 24 hours. Secondary endpoints were subjective alertness (Stanford Sleepiness Scale) postoperatively and attention (Stroop test), which were evaluated preoperatively and 24 hours after surgery. The mean change in pneumocephalus volume was higher in patients in the treatment arm as compared to patients in the control arm (p = 0.001). The air resorption rate was higher in patients in the treatment arm as compared to patients in the control arm (p = 0.0015). Differences were more pronounced in patients aged 52 years and older. No difference between patients in treatment arm and control arm was observed for the Stroop test. The distribution of scores in the Stanford Sleepiness Scale differed in the treatment arm as compared to the control arm, and there was a difference in mean values (p = 0.015).ConclusionsAdministration of normobaric hyperoxia at FiO2 100% via an endotracheal tube for 3 hours is safe and efficacious in the treatment of pneumocephalus after posterior fossa surgery in the semisitting position. Largest benefit was found in elderly patients and particularly in older men.Trial RegistrationGerman Clinical Trials Register DRKS00006273

Carbon dioxide field flooding reduces the hemodynamic effects of venous air embolism occurring in the sitting position.

Although the utility of the sitting position is undisputed for biomechanical and ergonomic reasons, it has been debated in recent years for its risks, particularly venous air embolism (VAE). In order to reduce the hemodynamic effect of VAE, we changed the composition of the surgical field air partially replacing nitrogen with carbon dioxide (CO2) that better dissolves in human tissues. First, we tested our method on a test dummy in the sitting position. Infrared CO2 sensors were placed close to the wound opening and on the facial mask of the surgeon. An oxygen sensor was connected to a computer for data recording (ALTAIR(®), MSA Safety). This model showed that 10 L/min CO2 flow provides efficient air displacement, maintaining safety for the surgeon. We reproduced the above-described surgical field environment in ten consecutive cases of posterior fossa surgery performed in the sitting position. A homogeneous group of ten patients operated in the sitting position with standard setting environment was used for control. We intraoperatively monitored VAE with trans-esophageal echocardiography (TEE), end-tidal CO2 (ETCO2), CO2 arterial pressure (PaCO2), and hemodynamic changes. Although the percentage of VAE was 70% in both groups, hemodynamic effects occurred in 10% of cases in the study group and in 40% of cases in the control group. Our preliminary study shows that a CO2-enriched sitting position surgical microenvironment significantly reduces the hemodynamic effects of VAE, more likely because arterial CO2 emboli are more soluble and consequently much better tolerated than air emboli.

A cadaveric study in endoscopic 3D visualization of posterior fossa neurovascular complexes

Background: The use of 3D endoscopy for posterior fossa surgery gradually adopted. In this study we compare the 3D to classic 2D endoscopy in evaluating neurovascular complexes in posterior fossa. Methods: Twenty retrosigmoid craniotomies, with a maximal diameter of 2cm were performed under neuronavigation on 10 fresh cadaveric heads. The posterior fossa dura matter was opened with a C-shaped incision and the base of the dural flap was placed over the sigmoid sinus. We used 3D and 2D endoscopes, with 0 and 45 degree angulations, connected to high definition camera lenses for optimal visualization of posterior fossa structures. Results: The superior, middle and inferior neurovascular complexes of the cerebellopontine angle were better visualized with 3D comparing to 2D endoscope. A detailed view of the porus trigeminous and structures associated with the tentorial incisura was also attained with 3D endoscopy. Conclusion: The high quality and resolution obtained by 3D endoscopy makes it a potentially valuable surgical and teaching tool in the armamentarium for endoscopic posterior fossa surgery. The stereoscopic view of the critical neurovascular structures of the posterior fossa, offered by 3D images, allows for a more detailed dissection in the difficult area of the cerebellopontine angle.

Patient adaptable cerebellar retractor system: Use in posterior fossa surgery

Abstract A new patient adaptable dual use soft tissue spreader and cerebellar retractor system designed for use during surgery of the posterior fossa is described. We found that this new retractor design allowed for excellent exposure, plus greater freedom and dexterity during the posterior fossa surgery. This novel instrument is an improvement over the existing instrument, because it provided more force/power transmission from pins/connectors to the brain spatula via the shorter flexible arm.

Comparison of outcomes following complex posterior fossa surgery performed in the sitting versus lateral position

The sitting position during surgery is thought to provide important advantages, yet it remains controversial. We compared surgical and neurological outcomes for patients operated on in the sitting versus lateral position. Technically difficult procedures performed from the years 2001–2008 for complex lesions in the posterior fossa (vestibular schwannomas, other cerebellopontine angle tumors, foramen magnum meningiomas, brainstem cavernomas, pineal region tumors) were included. Outcomes in the two surgical positions were compared for all 243 patients (93 sitting, 38.3%; 150 lateral, 61.7%) and for 130/243 patients with vestibular schwannomas (50 sitting, 38.5%; 80 lateral, 61.5%). Sitting and lateral patient subgroups were clinically comparable. There were no surgical mortalities. The extent of removal and surgical and neurological outcomes were comparable. We found no advantage in surgical or neurological outcomes for use of the sitting or lateral surgical positions in technically difficult posterior fossa procedures. In vestibular schwannoma surgeries facial nerve preservation (House–Brackmann score 1–2) was related to extent of resection but not to surgical position. The choice of operative position should be based on lesion characteristics and the patient’s preoperative medical status as well as the experience and preferences of the surgeons performing the procedure.

MRI findings of olivary degeneration after surgery for posterior fossa tumours in children: incidence, time course and correlation with tumour grading.

Olivary degeneration is due to many posterior cranial fossa (PCF) lesions affecting the dentato-rubro-olivary pathway, also known as Guillain-Mollaret triangle. Triangle damage results in hyperexcitation and consequently in hypertrophy of the inferior olivary nucleus (ION). The aim of our study was to evaluate the incidence of magnetic resonance (MR) imaging changes in the ION after surgery in a large cohort of paediatric patients and to determine their correlation with tumour grade. We retrospectively evaluated 58 patients treated surgically for PCF tumours who underwent MR imaging between 2007 and 2014, 1week to 5years after surgery. Histopathology revealed 29 medulloblastomas (WHO IV), 6 ependymomas (WHO II), 2 anaplastic ependymomas (WHO III) and 21 pilocytic astrocytomas (WHO I). ION MR imaging changes were correlated with surgery-to-MR interval and with tumour grading. ION MR imaging changes were observed in 19/64 (33%), and all consisted of T2 signal alterations, 15 bilateral and four unilateral, with dentate nucleus damage in all cases. Olivary enlargement was observed in few cases only (7/19). ION T2 hyperintensity was always present between 1 and 6months after surgery with a trend to decrease, becoming faint after 1year. The Fisher test demonstrated a significant (p=0.005) correlation between ION MR imaging changes and high tumour grade. Our results demonstrate that olivary degeneration, with or without hypertrophy, is a relatively frequent consequence of posterior fossa surgery, particularly in children treated for high-grade tumours. Knowledge of this condition can prevent misdiagnoses and unnecessary investigations.

I‐gel Laryngeal Mask Airway Combined with Tracheal Intubation Attenuate Systemic Stress Response in Patients Undergoing Posterior Fossa Surgery

Background. The adverse events induced by intubation and extubation may cause intracranial hemorrhage and increase of intracranial pressure, especially in posterior fossa surgery patients. In this study, we proposed that I-gel combined with tracheal intubation could reduce the stress response of posterior fossa surgery patients. Methods. Sixty-six posterior fossa surgery patients were randomly allocated to receive either tracheal tube intubation (Group TT) or I-gel facilitated endotracheal tube intubation (Group TI). Hemodynamic and respiratory variables, stress and inflammatory response, oxidative stress, anesthesia recovery parameters, and adverse events during emergence were compared. Results. Mean arterial pressure and heart rate were lower in Group TI during intubation and extubation (P < 0.05 versus Group TT). Respiratory variables including peak airway pressure and end-tidal carbon dioxide tension were similar intraoperative, while plasma β-endorphin, cortisol, interleukin-6, tumor necrosis factor-alpha, malondialdehyde concentrations, and blood glucose were significantly lower in Group TI during emergence relative to Group TT. Postoperative bucking and serious hypertensions were seen in Group TT but not in Group TI. Conclusion. Utilization of I-gel combined with endotracheal tube in posterior fossa surgery patients is safe which can yield more stable hemodynamic profile during intubation and emergence and lower inflammatory and oxidative response, leading to uneventful recovery.

Asystole Due to Saline Irrigation during a Posterior Fossa Surgery: A Case Report

Posterior fossa surgery (PFS) is one of the most complicated surgeries in the neurosurgery field. Asystole is a severe complication during this type of surgeries. Trigemino cardiac reflex (TCR) is hypothesized to stimulate the asystole. The case of a 40 year old female who established a cardiac arrest is reported when the surgeon was flooding the field with normal saline at the end of the surgery. A good knowledge of TCR is important and a close monitor should continue till the end of surgery.

Experiences with the Sitting Position in Posterior Fossa Surgery in 310 Patients

Introduction: The sitting position for lesions in the posterior fossa has been controversially discussed in the literature because of high risk of air embolism. We report our experience with the sitting position and evaluate the risk of air embolism. Material and Methods: We performed a retrospective analysis of patient charts (N=310), surgical and anesthesiological reports to evaluate the occurrence of intraoperative complications. Pre and post-operative MRIs were also evaluated for occurrence of embolic infarctions. The patients were operated in our department from 2009–2013. Results: Only 0.6% of patients suffered from embolic infarctions. Most of the complications were similar to the complications which occur in the lateral oblique position. Preoperatively, all patients were evaluated with echocardiography to exclude a patent foramen ovale (those patients were not operated in the sitting position). Conclusion: The sitting position is excellent for surgery in the posterior fossa since blood is washed out and does not intervene with the surgical field. The risk of air embolism is very low when a patent foramen ovale has been excluded. Intraoperatively, a right ventricular catheter is inserted to aspirate air if needed. Meticulous coagulation, irrigation of the surgical domane and application of bone wax to the craniotomy edges reduces the risk of venous air embolism.

In-situ Cranioplasty after Microvascular Decompression: A Technical Note.

Cranioplasty is not only performed for cosmetic reasons but also for physiological requirements to balance the cerebral hemodynamics and to protect the brain from external traumas. Methyl methacrylate is one of the most preferred materials for cranioplasty. It is usually prepared out of the surgical site and therefore modelling of the cranioplasty material to fit the bone defect is sometimes difficult. In this technical note, we present our new technique of cranioplasty with methyl methacrylate in which the material is prepared on site of the bone defect and very easily shaped. Fixation materials are not needed. This technique is especially suitable for posterior fossa surgeries after craniectomy.

Cerebral salt wasting syndrome in the posterior fossa surgery post-operative period: Case report

Hyponatremia is the most common electrolyte disorder following intracranial surgery. Its aetiology is multifactorial. We present a case of a patient taken to microvascular decompression (Janetta surgery) for the treatment of trigeminal neuralgia who developed a symptomatic magnification of basal hyponatremia in the immediate post-operative period. Cerebral salt wasting syndrome was diagnosed. The management of this condition poses a challenge for physicians involved in postoperative neurosurgical care.