Modified Transpetrosal-Transtentorial Approach for Resection of Large and Giant Petroclival Meningioma: Technical Nuance and Surgical Experiences

BACKGROUND

 Meningiomas arising from the petroclival area remain a challenge for neurosurgeons. Various approaches have been proposed to achieve maximum resection with minimal morbidity and mortality. Also, some articles correlated preservation of adjacent veins with less neurologic deficits.

OBJECTIVE

 To describe the experiences in using a new technique to achieve maximal resection of petroclival meningiomas and preserving the superior petrosal veins (SPVs) and the superior petrosal sinus (SPS).

METHODS

 A retrospective analysis of 26 patients harboring a true petroclival meningioma with a diameter ≥25 mm and undergoing surgery with the modified transpetrosal-transtentorial approach (MTTA) was performed.

RESULTS

 Fifty-four percent of 22 patients complained of severe headache at presentation. There was also complaint of cranial nerve (CN) deficit, with CN VII deficit being the most common (present in 42% of patients). The average tumor size (measured as maximum diameter) was 45.2 mm, and most of the tumors compressed the brainstem. Total resection was achieved in 12 patients (46.2%), whereas the others were excised subtotally (54.8%). Most of the patients had WHO grade I (96.1%) meningioma; only one had a grade II (3.8%) meningioma. In addition, clinical improvement and persistence of symptoms were observed in 17 (65.4%) and 8 (30.7%) patients, respectively, and postoperative permanent CN injury was observed in 3 (11.5%) patients.

CONCLUSION

 Using the MTTA, maximal resection with preservation of the CNs and neurovascular SPV-SPS complex can be achieved. Therefore, further studies and improvements of the technique are required to increase the total resection rate without neglecting the complications that may develop postoperatively.

Lifesaving Decompressive Craniectomy for High Intracranial Pressure Attributed to Deep-Seated Meningioma: Emergency Management

Objects:

As the most common intracranial extra-axial tumor among adults who tend to grow slowly with minimal clinical manifestation, the patients with meningioma could also fall in neurological emergency and even life-threatening status due to high intracranial pressure (ICP). In those circumstances, decompressive craniectomy (DC) without definitive tumor resection might offer an alternative treatment to alleviate acute increasing of ICP. The current report defines criteria for the indications of lifesaving DC for high ICP caused by deep-seated meningioma as an emergency management.

Patients and Methods:

This study collected the candidates from 2012 to 2018 at Dr. Soetomo General Hospital, Surabaya, Indonesia. The sample included all meningioma patients who came to our ER who fulfilled the clinical (life-threatening decrease in Glasgow Coma Scale [GCS]) and radiography (deep-seated meningioma, midline shift in brain computed tomography [CT] >0.5 cm, and diameter of tumor >4 cm or tumor that involves the temporal lobe) criteria for emergency DC as a lifesaving procedure. GCS, midline shift, tumor diameter, and volume based on CT were evaluated before DC. Immediate postoperative GCS, time to tumor resection, and Glasgow Outcome Scale (GOS) were also assessed postoperation.

Results:

The study enrolled 14 patients, with an average preoperative GCS being 9.29 ± 1.38, whereas the mean midline shift was 15.84 ± 7.02 mm. The average of number of tumor's diameter and volume was 5.59 ± 1.44 cm and 66.76 ± 49.44 cc, respectively. Postoperation, the average time interval between DC and definitive tumor resection surgery was 5.07 ± 3.12 days. The average immediate of GCS postoperation was 10.07 ± 2.97, and the average GOS was 3.93 ± 1.27.

Conclusion:

When emergency tumor resection could not be performed due to some limitation, as in developing countries, DC without tumor resection possibly offers lifesaving procedure in order to alleviate acute increasing ICP before the definitive surgical procedure is carried out. DC might also prevent a higher risk of morbidity and postoperative complications caused by peritumoral brain edema.

Burr hole drainage without irrigation for chronic subdural hematoma

Background:

Chronic subdural hematoma (CSDH) is one of the most common neurosurgical conditions, with different strategies for treatment. Most recent trials favor the use of drainage to reduce the recurrence rate. However, few reports have discussed the efficacy of burr hole drainage without irrigation for treating CSDH. This study aimed to examine the efficacy of burr hole drainage without irrigation in a series of 385 symptomatic CSDH lesions.

Methods:

This retrospective study included a series of 385 symptomatic CSDH lesions in 309 patients, who underwent burr hole drainage without irrigation, between September 2009 and August 2017 at the Department of Neurosurgery, Yao Tokushukai General Hospital, Japan. The risk of recurrence was evaluated based on the patients’ age, sex, preoperative magnetic resonance imaging (MRI) findings, preoperative anticoagulants, hematoma drainage rate, and bilaterality.

Results:

Of the 385 lesions, 41 cases (16 with inadequate follow-up periods and 25 with contraindications for MRI) were excluded from the analysis. The overall recurrence rate in the index study was 4.9% (17/344 lesions). The effects of the preoperative hematoma volume and nonhyperintensity on T1-weighted imaging on the recurrence rate were significant.

Conclusion:

Our findings indicated that burr hole drainage without irrigation is a good surgical modality in patients with CSDH, and preoperative MRI findings can evaluate the risk of recurrence.

Acromegaly in preadolescence: A case report of a 9-year-old boy with acromegaly

Background:

Acromegaly has been reported in adolescents and young adults, but it is unusual in preadolescence. Diagnosis and management pose different challenges in this age group. Here, we present a rare case of acromegaly in preadolescence.

Case Description:

A 9-year-old boy presented with acromegalic features and MRI revealed a pituitary tumor. He was diagnosed as having growth hormone secreting pituitary adenoma based on the multidisciplinary assessment, and underwent gross total tumor resection through an endoscopic endonasal approach (EEA) with subsequent normalization of the hormonal parameters.

Conclusions:

Advances in EEA have made safe removal and cure possible even in children. However, long- term follow-up is needed in such younger patients with multidisciplinary management by neurosurgeons, endocrinologists, pediatricians, and ENT surgeons.

Significance and Indications of Surgery for Asymptomatic Nonfunctioning Pituitary Adenomas

BACKGROUND

The availability of magnetic resonance imaging (MRI) has led to an increase in the detection of pituitary incidentaloma (PI). However, there are no robust data on surgical treatment of PI on which to base therapeutic recommendations. This study was performed to investigate the significance of surgery for asymptomatic nonfunctioning pituitary adenoma (NFPA) among PIs.

METHODS

A total of 180 patients that underwent tumor resection of pituitary adenoma via the transsphenoidal approach between 2005 and 2017 were reviewed. Thirty-three consecutive patients with subjectively asymptomatic NFPA were included in this study. Our surgical indications for asymptomatic NFPAs were categorized as follows: macroadenoma with optic chiasma compression (group A, n = 14), solid tumor ≥2 cm in size (group B, n = 7), and tumor growth on follow-up MRI (group C, n = 12). The clinical outcomes were analyzed accordingly.

RESULTS

Seven patients (50%) in group A showed subjective improvement of visual function after tumor resection even though they had no complaints preoperatively. On the other hand, no changes occurred in any cases in group B or group C. Although there were no critical complications in this series, the incidence of nonnegligible nasal complications was relatively high (24.2%) and may decrease the patient's quality of life.

CONCLUSIONS

Surgery should be recommended for asymptomatic NFPA with optic chiasma compression to improve visual outcome. On the other hand, immediate intervention for other asymptomatic NFPA to reduce the likelihood of the appearance of tumor-related symptoms remains questionable considering its invasiveness to the nose.

Surgical implementation and efficacy of endoscopic endonasal extradural posterior clinoidectomy

OBJECTIVE

The endoscopic endonasal approach (EEA) for skull base tumors has become an important topic in recent years, but its use, merits, and demerits are still being debated. Herein, the authors describe the nuances and efficacy of the endoscopic endonasal extradural posterior clinoidectomy for maximal tumor exposure.

METHODS

The surgical technique included extradural posterior clinoidectomy following lateral retraction of the paraclival internal carotid artery and extradural pituitary transposition. In cases with prominent posterior clinoid process, a midline sellar dura cut was added to facilitate extradural exposure. Forty-four consecutive patients, in whom this technique was performed between 2016 and 2018 at Osaka City University Hospital, were reviewed. The pathology included 19 craniopharyngiomas, 7 chordomas, 6 meningiomas, 6 pituitary adenomas, 4 chondrosarcomas, and 2 miscellaneous. Utilization and effectiveness of this approach were further demonstrated with neuroimaging.

RESULTS

Extradural posterior clinoidectomies were successfully applied in all patients without permanent neurovascular injury and with better maneuverability and greater resection rate of the tumors. Four patients experienced transient postoperative abducens nerve paresis, and 1 patient experienced transient postoperative oculomotor nerve paresis; however, the patients with deficits recovered within 3 months. On radiological examination, the surgical field was 2.2 times wider in cases with bilateral posterior clinoidectomy than in cases without posterior clinoidectomy.

CONCLUSIONS

The extended EEA with extradural posterior clinoidectomy creates an extra working space and allows adequate accessibility with safe surgical maneuverability to remove tumors that extend behind the posterior clinoid and dorsum sellae.

Overcoming Daunting Challenges of Clipping of Paraclinoid Carotid-Ophthalmic and Superior Hypophyseal Artery Aneurysms: 2-Dimensional Operative Video

This surgical video emphasizes the nuances that needed to overcome daunting challenges of clipping of paraclinoid carotidophthalmic and superior hypophyseal artery (SHA) aneurysms. To avoid hazardous manipulations, scarifying the ipsilateral SHA under visual evoked potential (VEP) guidance can be done without risk of postoperative visual decline. This technique is associated with better visual outcome.1 A 66-yr-old woman presented with gradually enlarging right paraclinoid carotidophthalmic and SHA aneurysms. The relationship between those aneurysms and the critical neurovascular structures made us facing a daunting challenge to preserve the visual function. To preserve the patency of the ophthalmic artery (oph.A), endovascular intervention was abandoned and a direct clipping surgery was selected. Following VEP settings, exposure of the cervical internal carotid artery for proximal control and right frontotemporal craniotomy, a subfrontal approach was used. To get adequate accessibility and safe maneuverability, the anterior clinoidectomy and unroofing of the optic canal were completed, then, the falciform ligament and the distal dural ring were carefully opened. Under VEP guidance, the oph.A and SHAs were temporarily occluded. VEP had been stable under repeated occlusions. The carotidophthalmic aneurysm was clipped with preservation of the oph.A. Besides, 1 ipsilateral SHA was sacrificed to achieve complete clipping of the SHA aneurysm. Final indocyanine green videoangiography confirmed obliteration of the paraclinoid aneurysms and patency of the oph.A, the other SHA and the tiny arterioles around the optic nerve. The postoperative course was uneventful. There was no evidence of postoperative visual disturbances. The patient has consented to the submission of the case report to the journal.

Spheno-Orbital Meningioma: Surgical Outcomes and Management of Recurrence

OBJECTIVE

Spheno-orbital meningioma (SOM) is a rare intracranial tumor that arises at the sphenoid wing, extends into the orbit, and is associated with hyperostosis of the sphenoid bone. These tumors often invade important neurovascular structures around the orbital apex, superior orbital fissure, and cavernous sinus. Aggressive tumor removal could achieve acceptable control; however, residual tumor can regrow. In this article, our surgical management and long-term outcomes are described.

METHODS

Retrospectively, 12 patients with SOM who were treated surgically over a 21-year period were included. The clinical features and long-term tumor control were evaluated.

RESULTS

Participants comprised 12 patients (5 men and 7 women). Mean follow-up was 74.4 months (range, 10-262 months). Ten patients (83%) were identified as World Health Organization grade 1 (WHO-I), and 2 patients (17%) were identified as WHO grade 2 (WHO-II). We encountered 4 recurrences, 2 of which needed additional surgeries. One patient with WHO-I (10%) experienced recurrence 10 years after the initial surgery and required a second surgery. Two patients with WHO-I (20%) showed slight regrowth of residual tumor around the superior orbital fissure; nevertheless, additive therapy was not recommended. Despite radical tumor resection, including eyeball and adjunctive radiotherapy for 1 patient with WHO-II, tumor recurrence in the posterior fossa was documented 19 years after the initial aggressive surgery.

CONCLUSIONS

SOM follows a relatively benign clinical course given the invasive radiologic findings. Abnormal bone resection is paramount to prevent early-stage recurrence. Although intradural residual tumor might regrow, additional surgery could achieve reasonable long-term tumor control with better outcome.

Watertight Robust Osteoconductive Barrier for Complex Skull Base Reconstruction: An Expanded-endoscopic Endonasal Experimental Study

Endoscopic skull base reconstruction (ESBR) following expanded-endoscopic endonasal approaches (EEA) in high-risk non-ideal endoscopic reconstructive candidates remains extremely challenging, and further innovations are still necessary. Here, the aim is to study the reconstructive knowledge gap following expanded-EEA and to introduce the watertight robust osteoconductive (WRO)-barrier as an alternative durable option. Distinctively, we focused on 10 clinical circumstances. A 3D-skull base-water system model was innovated to investigate the ESBR under realistic conditions. A large-irregular defect (31 × 89 mm) extending from the crista galli to the mid-clivus was achieved. Then, WRO-barrier was fashioned and its tolerance was evaluated under stressful settings, including an exceedingly high (55 cmH₂O) pressure, with radiological assessment. Next, the whole WRO-barrier was drilled to examine its practical-safe removal (simulating redo-EEA) and the whole experiment was repeated. Finally, WRO-barrier was kept into place to value its 18-month long-term high-tolerance. Results in all experiments of WRO-barriers were satisfactorily fashioned to conform the geometry of the created defect under realistic circumstances via EEA, tolerated an exceedingly high pressure without evidence of leak even under stressful settings, resisted sudden-elevated pressure, and remained in its position to maintain long-term watertight seal (18 months), efficiently evaluated with neuroimaging and simply removed-and-reconstructed when redo-EEA is needed. In conclusion, WRO-barrier as an osteoconductive watertight robust design for cranial base reconstruction possesses several distinct qualities that might be beneficial for patients with complex skull base tumours.

Intelligent Surgeon's Arm Supporting System iArmS in Microscopic Neurosurgery Utilizing Robotic Technology

BACKGROUND

Based on our previous reports, stabilizing the surgeon's arm with an intraoperative armrest is linked to improved precision of microsurgical and endoscopic procedures. We developed the robotic intelligent surgeon's arm supporting system iArmS, which automatically follows the surgeon's arm and fixes it at an adequate position.

METHODS

iArmS has 3 states-free, hold, and wait-which can be carefully chosen automatically as follows: In free state, the armholder follows the surgeon's arm. In hold state, iArmS supports the surgeon's arm weight by fixing the armholder. In wait state, the surgeon can move his or her arm away from the armholder. Also, the surgeon can change the armrest position while looking through the microscope and can continue the microsurgical procedure while holding surgical instruments. From February 2015 to January 2017, iArmS was used in 108 microsurgeries at 3 of the authors' institutions by 14 board-certified neurosurgeons, including the authors. After using iArmS, to quantify neurosurgeons' satisfaction, a scaling evaluation guide based on visual analog scales was designed to be completed by contributing neurosurgeons, including authors.

RESULTS

iArmS decreased fatigue and reduced hand trembles experienced by surgeons. Continuous accurate motions of microinstruments were performed without any difficulties. There were no complications related to use of iArmS.

CONCLUSIONS

iArmS allows continuous precise manipulations that provide high-quality surgical results in neurosurgical techniques. Moreover, iArmS is a useful automatic tool for holding and following the surgeon's arm.

Cystic Lymphocytic Hypophysitis Mimicking Pituitary Apoplexy: Daunting Challenge

BACKGROUND

Inflammatory lesions of the pituitary gland including hypophysitis are poorly understood, and it is difficult to make a correct diagnosis on the basis of only clinical and radiologic findings.

CASE DESCRIPTION

An otherwise healthy 68-year-old man presented with sudden onset of headache, visual impairment, and pituitary insufficiency. Magnetic resonance imaging revealed a pituitary mass with cystic component showing changing intensity on follow-up images. Also, changing density of the lesion was demonstrated on computed tomography over a short period of time. These findings suggested a hemorrhagic lesion, and a preoperative diagnosis of pituitary apoplexy associated with a preexisting pituitary adenoma was made on the basis of clinical and radiologic findings. In the endoscopic endonasal approach for tumor resection, there was neither hematoma nor adenoma. Histopathologic diagnosis was lymphocytic hypophysitis.

CONCLUSIONS

To the best of our knowledge, this is the first case report of hypophysitis with radiologic signal changes over a short period. Vigilant attention regarding the clinical diagnosis of such rare entity is paramount.

Pitfalls of skull base reconstruction in endoscopic endonasal approach

Various skull base reconstruction techniques have been developed in endoscopic endonasal approach (EEA) for skull base lesions to prevent postoperative cerebrospinal fluid (CSF) leakage. This study was performed to evaluate the efficacy and pitfalls of our method of skull base reconstruction after EEA. A total of 123 patients who underwent EEA (127 surgeries) between October 2014 and May 2017 were reviewed. Our algorithm for skull base reconstruction in EEA was categorized based on intraoperative CSF leakage graded as follows: grade 0 was excluded from this study; grade 1, dural suturing with abdominal fat graft or packing of gelatin sponge into the cavity; grade 2, method for grade 1 with addition of mucosal flap or nasoseptal flap (NSF); and grade 3, duraplasty in fascia patchwork closure with NSF. Bony reconstruction was not mandatory, and there was no postoperative bed rest or initial lumbar drainage (LD) insertion in any of the cases. Postoperative CSF leakage after EEA was mostly prevented (96.3%) by our algorithm without postoperative initial LD or bed rest. On the other hand, reconstruction surgery was required for postoperative CSF leakage in two cases-one with prior multitranssphenoidal surgery and radiotherapy and another patient with poor compliance due to communication difficulties. Both of the latter patients were obese. Greater care with regard to postoperative CSF leakage is required in patients with prior EEA with radiotherapy and obesity. In such high-risk patients, initial LD or bed rest may be required to prevent postoperative CSF leakage. It is also important to restrict activities that result in increased intracranial pressure.

Change in Cerebral Blood Flow after Palliative Percutaneous Angioplasty and Timing of Second Stage Carotid Artery Stenting in Staged Angioplasty

The purpose of this study is to elucidate the hemodynamic changes after palliative angioplasty and the timing of second stage carotid artery stenting (CAS) in staged angioplasty for patients with severe hemodynamically compromised carotid artery stenosis. Among consecutive 111 patients with carotid artery stenosis, chronological changes in the cerebral blood flow of all 11 hemodynamically compromised patients treated with CAS were evaluated with single photon emission computed tomogram (SPECT) in each stage of the treatment. Ten of these 11 patients underwent staged angioplasty and one was treated with single-stage CAS. All the 10 patients who underwent staged angioplasty showed improved cerebral vascular reactivity (CVR) on SPECT after the first stage palliative angioplasty. Only one patient treated with staged angioplasty with 4-week interval before the CAS showed restenosis of the lesion. Cerebral hyperperfusion syndrome (CHS) was not observed in nine of 10 patients with staged angioplasty. One patient of staged angioplasty (who presented restenosis at the time of elective CAS) and another patient in whom we could not apply staged angioplasty (for his renal dysfunction) showed CHS after CAS. In conclusion, restoration of CVR could be achieved within a few days following palliative angioplasty, and 1–2-week interval is enough for staged angioplasty.

Petroclival tension pneumocephalus: an unrivalled life threatening complication linked to molecular-targeted therapy

A 73-year-old man with a petroclival tumor (metastatic renal cell carcinoma) presented with a progressive consciousness disturbance attributed to tension pneumocephalus during molecular-targeted therapy following low-dose fractionated radiotherapy for a petroclival tumor. The skull base defect was successfully reconstructed vi an endoscopic endonasal approach.

Endoscopic endonasal transsphenoidal surgery using the iArmS operation support robot: initial experience in 43 patients

Objective The intelligent arm-support system, iArmS, which follows the surgeon's arm and automatically fixes it at an adequate position, was developed as an operation support robot. iArmS was designed to support the surgeon's forearm to prevent hand trembling and to alleviate fatigue during surgery with a microscope. In this study, the authors report on application of this robotic device to endoscopic endonasal transsphenoidal surgery (ETSS) and evaluate their initial experiences. Methods The study population consisted of 43 patients: 29 with pituitary adenoma, 3 with meningioma, 3 with Rathke's cleft cyst, 2 with craniopharyngioma, 2 with chordoma, and 4 with other conditions. All patients underwent surgery via the endonasal transsphenoidal approach using a rigid endoscope. During the nasal and sphenoid phases, iArmS was used to support the surgeon's nondominant arm, which held the endoscope. The details of the iArmS and clinical results were collected. Results iArmS followed the surgeon's arm movement automatically. It reduced the surgeon's fatigue and stabilized the surgeon's hand during ETSS. Shaking of the video image decreased due to the steadying of the surgeon's scope-holding hand with iArmS. There were no complications related to use of the device. Conclusions The intelligent armrest, iArmS, seems to be safe and effective during ETSS. iArmS is helpful for improving the precision and safety not only for microscopic neurosurgery, but also for ETSS. Ongoing advances in robotics ensure the continued evolution of neurosurgery.

Risks of Endoscopic Temporal Ventriculocisternostomy for Isolated Lateral Ventricle: Anatomic Surgical Nuances

BACKGROUND

Entrapment of the temporal horn, known as isolated lateral ventricle (ILV), is a rare type of noncommunicating focal hydrocephalus, and standard treatment has not been established. We report 2 cases of endoscopic surgery for ILV and highlight the anatomic surgical nuances to avoid associated surgical risks.

CASE DESCRIPTION

The first patient presented with recurrent ILV following initial shunt placement for ILV, owing to shunt malfunction. In the second patient, ILV recurred secondary to choroid plexus inflammation caused by cryptococcal infection. Endoscopic temporal ventriculocisternostomy was effective in both cases. However, in the second case, the choroidal fissure was fenestrated, which led to cerebral infarction in the territory of the choroidal artery zone, attributed to damage of the branches of the choroidal segment of the anterior choroidal artery.

CONCLUSIONS

Although endoscopic temporal ventriculocisternostomy is considered a safe and less invasive procedure for treatment of symptomatic ILV, the technique is still associated with risks. To avoid complications, it is necessary to be familiar with the anatomy of the choroidal arteries and the pertinent endoscopic intraventricular orientation. Additionally, sufficient experience is required before it can be recommended as the treatment of choice.

Clinical characteristics of pituitary adenomas with radiological calcification

BACKGROUND

Radiographic detection of calcification in pituitary adenoma is relatively rare, and the clinical characteristics of pituitary adenoma with calcification remain unclear. Herein, the clinical characteristics of pituitary adenoma with radiological calcification were investigated.

METHODS

A total of 160 patients who underwent surgical resection of pituitary adenomas between February 2004 and December 2016 were reviewed. Eighty-one patients had hormone-secreting pituitary adenomas, and 79 patients had nonfunctioning pituitary adenoma. Among these 160 patients, cases with radiological calcifications on preoperative neuroimaging were included in this study, and clinical characteristics with intraoperative findings were analyzed, retrospectively.

RESULTS

Pituitary adenoma with calcification on preoperative neuroimaging was observed in only nine cases (5.6%). The study population consisted of these nine patients with nonfunctioning pituitary adenoma (n = 5), mixed growth hormone and prolactin-secreting pituitary adenomas (n = 3), and a prolactinoma (n = 1). In 89% of cases (n = 8), calcified pituitary adenoma was soft enough for suction despite the presence of a granular gritty texture intraoperatively. Besides, in a single patient (11%), evidence of hard thick capsular calcification was seen surrounding a soft tumor component; however, it did not interfere with adequate removal of the soft part, and tumor resection was possible in all cases without any complications.

CONCLUSIONS

Pituitary adenoma presenting with calcification is relatively rare, but should be kept in mind to avoid making a wrong preoperative diagnosis. As not all pituitary adenomas with calcification are hard tumors, preoperative radiological calcification should not affect decision-making regarding surgical indications.

Management of hypertrophied dural lesions: Is surgery a better option?

It is often difficult to definitively diagnose dural lesions with hypertrophy as they exhibit nonspecific imaging findings and clinical symptoms. Most cases require histopathological evaluation with surgical intervention (such as biopsy). However, complications related to surgical interventions remain as matter of concern. Herein, we analyzed and verified the significance of surgery in 39 patients with hypertrophic dural lesions who were histopathologically diagnosed with surgical interventions. Specimens of dural lesions were obtained successfully, and it was possible to make a definitive diagnosis for each case based on histopathological findings. All patients tolerate the procedures well, and there were no evidences of surgery-related complications during surgical approach to the dura mater. Preoperative and pathological diagnoses varied in eight cases. Our results indicate that histopathological evaluation is important for distinguishing diseases showing dural hypertrophy even if surgical invasiveness is concerned. Neurosurgeons should not hesitate to perform surgery for management of dural lesions with hypertrophy in order to achieve accurate diagnosis.

Transjugular tubercle-preaccessory approach for ventrocaudally located PICA aneurysm

BACKGROUND

Posterior inferior cerebellar artery (PICA) aneurysms are often located in the ventral craniocervical junction. Such deep-seated aneurysms are usually treated with coil embolization. However, recurred and/or very small PICA aneurysms are hardly treated with an endovascular approach.

METHOD

We present a modification of the transcondylar fossa approach with intradural and extradural removal of the jugular tubercle. An adequate preaccessory surgical corridor was created with this novel technique.

CONCLUSION

The ventocaudal PICA aneurysm was clipped through the outside of the spinal accessory nerve without surgical manipulation of other lower cranial nerves. This approach is worthwhile to avoid dysphagia.

Significance of surgical management for cystic prolactinoma

PURPOSE

It is generally accepted that dopamine agonists (DA) represent the first-line treatment for most patients with prolactinoma, and patients become candidates for surgical intervention when DA is contraindicated. Surgical indication for cystic prolactinoma remains controversial. This study was performed to investigate the significance of surgery for cystic prolactinoma.

METHODS

A total of 28 patients that underwent transsphenoidal resection of prolactinoma between February 2004 and May 2016 were reviewed. Five consecutive patients with cystic prolactinoma were included in this study. Our surgical strategy for cystic prolactinoma was categorized as follows: first, when the purpose of surgical resection was normalization of the prolactin level, aggressive resection was performed; second, when volume reduction was essential to relieve the visual symptoms and headache, internal decompression was performed followed by DA therapy. The clinical outcomes were analyzed accordingly.

RESULTS

All cystic prolactinoma were resected via the transsphenoidal approach without any complications, and all symptoms including visual impairment and hypogonadal activity were finally relieved combined with medication.

CONCLUSIONS

Surgery for cystic prolactinoma could be a better option. Transsphenoidal surgery is relatively safe to remove the cystic prolactinoma, additionally it can normalize the prolactine level and achieve adequate and rapid decompression of optic chiasm. The risk of transsphenoidal surgery is highly dependent on the skill of the surgeon and treatment decision for cystic prolactinoma needs to be individualized for each patient.

Neuroendoscopy via an Extremely Narrow Foramen of Monro: A Case Report

Herein, safe and reliable neuroendoscopic biopsy via an extremely narrow foramen of Monro (ENFM) for a non-hydrocephalic patient with hypothalamic and pineal region tumors was successfully applied. A 17-year-old boy presented with hypothalamic manifestations attributed to hypothalamic and pineal region tumors. Small ventricles were seen. Intraoperatively, to advance different diameter steerable fiberscopes via ENFM, the third ventricle was flushed to induce a moment increase in the intraventricular pressure with subsequent dilatation of FM. Postoperative course was uneventful. Histopathological studies revealed a yolk sac tumor. Adjuvant therapy was applied. Follow-up neuroimaging disclosed marvellous improvement of the condition. His symptoms gradually improved.

Evaluation of Metallic Artifacts Caused by Nonpenetrating Titanium Clips in Postoperative Neuroimaging

BACKGROUND

Nonpenetrating titanium clips create no suture holes and thereby reduce cerebrospinal fluid leakage after dural closure. However, no data exist regarding metallic artifacts caused by these clips during postoperative neuroimaging. We aimed to evaluate clip-related artifacts on postoperative magnetic resonance (MR) images of 17 patients who underwent spinal surgery.

METHODS

A phantom study evaluated the size of metallic artifacts, and a clinical study evaluated the quality of postoperative spinal MR images. Both 1.5-T studies used T1-weighted and T2-weighted fast spin echo sequences. The phantom study compared clip and artifact size for 10 clips. Artifacts were defined as signal voids surrounded by high signal amplitude that followed the clip shape. In the clinical study, 2 neurosurgeons assessed 22 images from 17 patients of the spinal cord, cauda equina, and paravertebral muscles adjacent to the nonpenetrating titanium clips, using 5-point scales.

RESULTS

Mean metallic artifact sizes were 4.82 ± 0.16 mm (T1) and 4.66 ± 0.25 mm (T2; P < 0.001 vs. control). The former and latter were respectively 207% and 200% larger than the clip size. Both readers graded spinal cord and paravertebral muscles images as 3 or 4, indicating very good image quality regardless of clip-related artifacts, with excellent interobserver agreement (κ = 0.99 and 0.98, respectively).

CONCLUSIONS

Metallic artifacts caused by nonpenetrating titanium clips were 200% larger than the actual clip but did not affect spinal cord and extradural tissue visualization. The use of these clips for closing the spinal dura mater does not alter postoperative radiologic evaluation quality.

Relationship Between Successful Extracranial-Intracranial Bypass Surgeries and Ischemic White Matter Hyperintensities

BACKGROUND AND PURPOSE

Few studies have described regression of white matter hyperintensities (WMHs); however, no studies have described their recurrence or fluctuation. Thus, we aimed to study the course of WMHs on fluid-attenuated inversion recovery (FLAIR) magnetic resonance image (MRI) after extracranial-intracranial (EC-IC) bypass surgery and its correlation with the clinical outcome.

METHODS

We enrolled perioperative FLAIR MRIs of 12 patients with WMHs who underwent EC-IC bypass surgeries because of ischemic-vascular stenosis with postoperative improvement of the cerebral blood flow confirmed by (123)I-iodoamphetamine single-photon emission computed tomography. Correlation between WMHs and cerebral blood flow was confirmed by perioperative single-photon emission computed tomography and diffusion-weighted imaging MRI. The WMHs were assessed visually with meticulous volumetric grading. Depending on postoperative changes among different grades, the WMHs course was determined to be improved, fluctuating, worsened, or unchanged. A statistical analysis was performed on the course of WMHs over time.

RESULTS

Imaging analysis was done with FLAIR MRI in 12 patients. The course of WMHs over time was 41.7% improvement, 33.3% fluctuation, 16.7% unchanged, and 8.3% worsening of the deep WMHs. After unilateral bypass surgery, 80% of the improved WMHs occurred bilaterally. Among patients with improved clinical outcomes, 16.7% showed improvement and 33.3% showed fluctuation, whereas in patients with unchanged clinical outcomes, 25% showed improvement of their WMHs on follow-up FLAIR MRIs.

CONCLUSIONS

This study might be considered the first step to find a relationship between successful EC-IC bypass surgeries and the course of ischemic WMHs. It could also open the door for further studies to make more solid conclusions.

Dural Arteriovenous Fistula Could Be Due to Hemodynamic Disturbance in Dural Physiological Shunts? Histopathological Study and a Case Report

BACKGROUND

Histopathologic studies of dural arteriovenous fistulas (dAVFs) are important for clarifying the pathogenesis. We present a case of Cognard type IV dAVF with detailed histopathologic studies in correlation with radiologic and intraoperative findings.

CASE DESCRIPTION

An otherwise asymptomatic 53-year-old man presented with chronic headache. Neurologic examination revealed no abnormalities. Neuroimaging and cerebral catheter angiographic studies disclosed a left frontoparietal dAVF close to the middle third of the superior sagittal sinus, fed by the left superficial temporal and bilateral middle meningeal arteries and draining into ectatic cortical and dural veins. No evidence of superior sagittal sinus thrombosis or occlusion was seen. Intraoperatively, the parietal branch of the left superficial temporal artery penetrated the skull vault to feed the fistula; arterialized cortical and draining dural veins were also noted. Complete obliteration of the dAVF with removal of the affected dura mater was achieved safely. Histopathologic studies in serial sections documented a shunt point between the dural artery and the dural vein within the dura mater and a draining point between the dural and cortical veins.

CONCLUSIONS

On the basis of clinical, angiographic, intraoperative, and histologic findings in our case, we strongly excluded acquired etiologies.

Bony surface registration of navigation system in the lateral or prone position: technical note

BACKGROUND

Navigation systems have become essential tools in neurosurgery. Precise registration is indispensable for the accuracy of navigation. The rapid and precise registration by surface matching on the facial skin is possible using the landmarks of the face in the supine position. On the other hand, incomplete registration often occurs in the lateral or prone position due to the direction of the face and displacement of the skin by headpins and obscuring of the skin by the bispectral index monitor and many electrodes on the forehead as well as the eye patch. Surface matching on the occipital scalp is not suitable for registration because the shape of the occipital scalp is flat and it is compressed in the supine position when obtaining preoperative neuroimaging. To overcome this problem, the authors have developed a new method of registration designated as "bony surface registration" in which surface matching is achieved using the bony surface of the skull after exposure.

METHODS

Between June and December 2014, this technique was used in 23 patients and its effectiveness was examined.

RESULTS

Registration time was markedly shortened and useful navigation was achieved due to accurate registration in all patients.

CONCLUSIONS

This is the first report of a registration methodology for a navigation system in the lateral or prone position. This bony surface registration method is useful for navigation system image-guided surgery in the lateral or prone position.