RNF213-Related Vasculopathy: Various Systemic Vascular Diseases Involving RNF213 Gene Mutations: Review

Moyamoya disease (MMD) is a cerebrovascular disorder that is predominantly observed in women of East Asian descent, and is characterized by progressive stenosis of the internal carotid artery, beginning in early childhood, and a distinctive network of collateral vessels known as "moyamoya vessels" in the basal ganglia. Additionally, a prevalent genetic variant found in most MMD cases is the p.R4810K polymorphism of RNF213 on chromosome 17q25.3. Recent studies have revealed that RNF213 mutations are associated not only with MMD, but also with other systemic vascular disorders, including intracranial atherosclerosis and systemic vascular abnormalities such as pulmonary artery stenosis and coronary artery diseases. Therefore, the concept of "RNF213-related vasculopathy" has been proposed. This review focuses on polymorphisms in the RNF213 gene and describes a wide range of clinical and genetic phenotypes associated with RNF213-related vasculopathy. The RNF213 gene has been suggested to play an important role in the pathogenesis of vascular diseases and developing new therapies. Therefore, further research and knowledge sharing through collaboration between clinicians and researchers are required.

Lung adenocarcinoma metastasis within a pituitary neuroendocrine tumor: a case report with review of literature

Collision tumors involving the metastasis of malignant neoplasms to pituitary neuroendocrine tumors (PitNETs) are extremely rare. We herein report a case involving a patient with lung adenocarcinoma metastasis within a PitNET who exhibited relatively rapid progression of neurological symptoms. A 75-year-old man who underwent tumor resection 36 and 18 years prior to presentation for bladder and colon cancer, respectively, without recurrence presented with bitemporal hemianopsia, ptosis, and diplopia of the right eye. Subsequent magnetic resonance imaging (MRI) revealed a tumor 3.2 cm in diameter that extended from the anterior pituitary gland to the suprasellar region. Gadolinium-enhanced MRI of the tumor showed heterogeneous contrast enhancement. Considering the relatively rapid progression of neurological symptoms, semi-emergency endoscopic endonasal transsphenoidal surgery was performed. Histopathological examination revealed a group of thyroid transcription factor-1- and napsin A-positive papillary proliferating cells intermingled with α-subunit- and steroidogenic factor-1-positive PitNET cells. Thus, the patient was diagnosed with lung adenocarcinoma metastasis within a gonadotroph PitNET. Genetic testing revealed the presence of an EGFR (Ex-19del) mutation, after which chemotherapy was initiated. Additional stereotactic radiotherapy was performed for the residual tumor in the sella turcica. With continued chemotherapy, good control of both the primary and metastatic tumors was noted after 24 months after surgery. Cases of malignant neoplasm metastasis within a PitNET are difficult to diagnose. In the case of a sella turcica tumor with relatively rapid progression of neurological symptoms, early surgical intervention is recommended given the possibility of a highly proliferative tumor and the need to obtain pathologic specimens.

Endoscopic spinal cord untethering using a 1 cm skin incision technique in pediatrics: a technical case report

BACKGROUND

Spinal cord untethering by sectioning the filum terminale is commonly performed in tethered cord syndrome patients with minor abnormalities such as filar lipoma, thickened filum terminale, and low conus medullaris. Our endoscopic surgical technique, using the interlaminar approach, allows for sectioning the filum terminale through a very small skin incision. To our knowledge, this procedure has not been previously reported. This is the first case report involving a 1 cm skin incision.

CASE PRESENTATION

A 9-month-old male patient was referred to our neurosurgical department due to a coccygeal dimple. MRI revealed a thickened fatty filum. After considering the treatment options for this patient, the parents agreed to spinal cord untethering. A midline 1 cm skin incision was made at the L4/5 vertebral level. Untethering by sectioning the filum terminale was performed by full endoscopic surgery using the interlaminar approach. The procedure was uneventful and there were no postoperative complications.

CONCLUSIONS

In terms of visibility and minimizing invasiveness, our surgical technique of using the interlaminar approach with endoscopy allows for untethering by sectioning the filum terminale through a very small skin incision.

Concurrent IgG4-related hypophysitis and clinically nonfunctioning gonadotroph pituitary neuroendocrine tumor

BACKGROUND

Some patients develop immunoglobulin G4 (IgG4)-related hypophysitis associated with systemic diseases. More than 30 cases of IgG4-related hypophysitis have been reported. However, biopsy has rarely been performed in these patients, and none have had an associated pituitary neuroendocrine tumor (PitNET). We present a case of concurrent IgG4-related hypophysitis and PitNET.

CASE PRESENTATION

A 56-year-old Japanese man arrived at the hospital with visual impairment, bitemporal hemianopia, and right abducens nerve palsy. Magnetic resonance imaging revealed pituitary body and stalk swelling as well as a small poorly enhanced right anterior lobe mass. Laboratory and loading test results suggested hypopituitarism. Because IgG4 level was elevated, a systemic examination was performed; multiple nodules were found in both lung fields. The diagnosis was based on an endoscopic transnasal biopsy of the pituitary gland. A histopathological examination revealed a marked infiltration of plasma cells into the pituitary gland, which was strongly positive for IgG4. The histological features of the resected tumor were consistent with those of gonadotroph PitNET, which was immunohistochemically positive for follicle-stimulating hormone-β and steroidogenic factor-1, and no plasma cell infiltration was observed. Based on the histopathological examination results, steroid therapy was initiated, which reduced pituitary gland size and serum IgG4 levels.

DISCUSSION AND CONCLUSIONS

This is the first reported case of IgG4-related hypophysitis with PitNET. Although no pathological findings indicating a relationship between the two conditions were found, we were able to preoperatively differentiate multiple lesions via detailed diagnostic imaging.

Creation of low cost, simple, and easy-to-use training kit for the dura mater suturing in endoscopic transnasal pituitary/skull base surgery

Training kits for laparoscopes for deep suturing under endoscopes are commercially available; however, previously reported training kits for endoscopic transnasal transsphenoidal pituitary/skull base surgery (eTSS) were not available in the market. Moreover, the previously reported low cost, self-made kit has the drawback of being unrealistic. This study aimed to create a low cost training kit for eTSS dura mater suturing that was as close to real as possible. Most necessary items were obtained from the 100-yen store ($1 store) or from everyday supplies. As an alternative to the endoscope, a stick-type camera was used. Through the assembly of the materials, a simple and easy-to-use training kit was created, which is almost identical to the actual dural suturing situation. In eTSS, a simple and easy-to-use training kit for dural suturing was successfully created at a low cost. This kit is expected to be used for deep suture operations and the development of surgical instruments for training.

An Overview of Pituitary Incidentalomas: Diagnosis, Clinical Features, and Management

Simple Summary

A pituitary incidentaloma is a pituitary tumor or mass that is incidentally discovered in imaging studies which have been performed for reasons other than the symptoms of pituitary lesions. The majority of pituitary incidentalomas are pituitary neuroendocrine tumors (PitNETs) and Rathke cleft cysts. PitNETs have received attention because of their distinction from pituitary adenoma in the new World Health Organization (WHO) classification. The natural history of PitNETs is partially known, and the management of pituitary incidentalomas has been determined based on this history; however, the pathology of PitNETs has significantly changed with the new WHO classification, and studies with a high level of evidence are required to consider treatment guidelines for pituitary incidentalomas.

Abstract

Pituitary incidentalomas are tumors or mass lesions of the pituitary gland. These are incidentally discovered during imaging studies for symptoms that are not causally related to pituitary diseases. The most common symptom that triggers an examination is headache, and the most common type of pituitary incidentalomas are pituitary neuroendocrine tumors (PitNETs) and Rathke cleft cysts. The existing treatment strategy is controversial; however, surgical resection is recommended in cases of clinically non-functioning PitNETs with optic chiasm compression. In contrast, cystic lesions, such as Rathke cleft cysts, should be followed if the patients are asymptomatic. In this case, MRI and pituitary function tests are recommended every six months to one year; if there is no change, the follow-up period should be extended. The natural history of PitNET is partially known, and the management of pituitary incidentalomas is determined by this history. However, the pathogenesis of PitNET has significantly changed with the new World Health Organization classification, and follow-up is important based on this new classification. Therefore, a high level of evidence-based research is needed to consider treatment guidelines for pituitary incidentalomas in the future.

Factors Influencing Long-Term Blood Flow in Extracranial-to-Intracranial Bypass for Symptomatic Internal Carotid Artery Occlusive Disease: A Quantitative Study

BACKGROUND

Maintaining the patency of extracranial-to-intracranial (EC-IC) bypass is critical for long-term stroke prevention. However, reports on the factors influencing long-term bypass patency and quantitative assessments of bypass patency are limited.

OBJECTIVE

To quantitatively evaluate blood flow in EC-IC bypass using four-dimensional (4D) flow magnetic resonance imaging (MRI) and investigate factors influencing the long-term patency of EC-IC bypass.

METHODS

Thirty-six adult Japanese patients who underwent EC-IC bypass for symptomatic internal carotid or middle cerebral artery occlusive disease were included. We examined the relationships between decreased superficial temporal artery (STA) blood flow volume and perioperative complications, long-term ischemic complications, patient background, and postoperative antithrombotic medications in patients for whom STA flow could be quantitatively assessed for at least 5 months using 4D flow MRI.

RESULTS

The mean follow-up time was 54.7 ± 6.1 months. One patient presented with a stroke during the acute postoperative period that affected postoperative outcomes. No recurrent strokes were recorded during long-term follow-up. Two patients died of malignant disease. Seven cases of reduced flow occurred in the STA, which were correlated with single bypass (P = .0294) and nonuse of cilostazol (P = .0294). STA occlusion was observed in 1 patient during the follow-up period. Hypertension, age, smoking, dyslipidemia, and diabetes mellitus were not correlated with reduced blood flow in the STA.

CONCLUSION

Double anastomoses and cilostazol resulted in long-term STA blood flow preservation. No recurrence of cerebral infarction was noted in either STA hypoperfusion or occlusion cases.

RNF213 c.14576G>A Is Associated with Intracranial Internal Carotid Artery Saccular Aneurysms

A mutation in RNF213 (c.14576G>A), a gene associated with moyamoya disease (>80%), plays a role in terminal internal carotid artery (ICA) stenosis (>15%) (ICS). Studies on RNF213 and cerebral aneurysms (AN), which did not focus on the site of origin or morphology, could not elucidate the relationship between the two. However, a report suggested a relationship between RNF213 and AN in French-Canadians. Here, we investigated the relationship between ICA saccular aneurysm (ICA-AN) and RNF213. We analyzed RNF213 expression in subjects with ICA-AN and atherosclerotic ICS. Cases with a family history of moyamoya disease were excluded. AN smaller than 4 mm were confirmed as AN only by surgical or angiographic findings. RNF213 was detected in 12.2% of patients with ICA-AN and 13.6% of patients with ICS; patients with ICA-AN and ICS had a similar risk of RNF213 mutation expression (odds ratio, 0.884; 95% confidence interval, 0.199-3.91; p = 0.871). The relationship between ICA-AN and RNF213 (c.14576G>A) was not correlated with the location of the ICA and bifurcation, presence of rupture, or multiplicity. When the etiology and location of AN were more restricted, the incidence of RNF213 mutations in ICA-AN was higher than that reported in previous studies. Our results suggest that strict maternal vessel selection and pathological selection of AN morphology may reveal an association between genetic mutations and ICA-AN development. The results of this study may form a basis for further research on systemic vascular diseases, in which the RNF213 (c.14576G>A) mutation has been implicated.

Role of RNF213 polymorphism in defining quasi-moyamoya disease and definitive moyamoya disease

OBJECTIVE

Quasi-moyamoya disease (QMMD) is moyamoya disease (MMD) associated with additional underlying diseases. Although the ring finger protein 213 (RNF213) c.14576G>A mutation is highly correlated with MMD in the Asian population, its relationship to QMMD is unclear. Therefore, in this study the authors sought to investigate the RNF213 c.14576G>A mutation in the genetic diagnosis and classification of QMMD.

METHODS

This case-control study was conducted among four core hospitals. A screening system for the RNF213 c.14576G>A mutation based on high-resolution melting curve analysis was designed. The prevalence of RNF213 c.14576G>A was investigated in 76 patients with MMD and 10 patients with QMMD.

RESULTS

There were no significant differences in age, sex, family history, and mode of onset between the two groups. Underlying diseases presenting in patients with QMMD were hyperthyroidism (n = 6), neurofibromatosis type 1 (n = 2), Sjögren's syndrome (n = 1), and meningitis (n =1). The RNF213 c.14576G>A mutation was found in 64 patients (84.2%) with MMD and 8 patients (80%) with QMMD; no significant difference in mutation frequency was observed between cohorts.

CONCLUSIONS

There are two forms of QMMD, one in which the vascular abnormality is associated with an underlying disease, and the other in which MMD is coincidentally complicated by an unrelated underlying disease. It has been suggested that the presence or absence of the RNF213 c.14576G>A mutation may be useful in distinguishing between these disease types.

Endoscopic third ventriculostomy and cerebrospinal fluid shunting for pure communicating hydrocephalus in children

PURPOSE

Recent reports regarding endoscopic third ventriculostomy (ETV) for pediatric hydrocephalus revealed that ETV could avoid cerebrospinal fluid (CSF) shunting in certain types of hydrocephalus. However, the effectiveness of ETV for "pure" communicating hydrocephalus that has no obstruction through CSF pathway is still unknown. In this study, we report clinical outcome of ETV and CSF shunting for communicating hydrocephalus and discuss the efficacy of ETV for pure communicating hydrocephalus.

METHODS

Children less than 15 years old who underwent ETV or CSF shunting for communicating hydrocephalus were retrospectively reviewed. The absence of obstruction through CSF circulation was confirmed by CT cisternography or cine-contrast image in MRI.

RESULTS

Sixty-three patients (45 CSF shunting and 18 ETV) were included. The mean follow-up period was 6.1 years. The success rate was 60% in CSF shunting and 67% in ETV at the last visit (p = 0.867). Normal development was observed in 24 patients (53%) in CSF shunting and 12 patients (67%) in ETV (p = 0.334). There was a significant difference in the mean time to failure (CSF shunting: 51.1 months, ETV 3.6 months, p = 0.004). The factor that affected success rate in ETV was the age at surgery (success 21.6 months, failure 4.4 months, p = 0.024) and ETV success score (success 66.7, failure 50.0, p = 0.047).

CONCLUSION

Clinical outcomes of ETV were not inferior to those of CSF shunting in patients with communicating hydrocephalus. Further studies is required to elucidate to establish the consensus of ETV as a treatment option for communicating hydrocephalus.

The validity of the simple methods of estimating chronic subdural hematoma volume

OBJECTIVES

It was reported that the XYZ/2 technique (using length, width and height of hematoma) is a simple and reliable method of estimation of chronic subdural hematoma volume. Two subtypes of techniques enable to adequately estimate, it is unclear which is more accurate. Computer-assisted volumetric analysis is widely considered the gold standard for CSDH volumetric analysis. It is important to consider the stability of analyses between examiners, because individual, decision-making differences may be relevant to the analysis, as hematoma margin and length are hand-operated. In this study, we investigated potential measurement biases of three neurosurgeons and analyzed the validity of the XYZ/2 technique by comparing it to the gold standard method.

METHOD

We retrospectively analyzed CT scans that indicated the need for an operation in 50 patients with CSDH in our department. Three neurosurgeons measured and calculated CSDH volumes independent of one another. We investigated potential measurement biases of three neurosurgeons and analyzed the validity of the XYZ/2 technique by comparing it to the gold standard method. The XYZ/2 technique includes the "maximal method" that uses the maximum length and maximum width of a slice to determine volume, and the "central method" that uses only the central slice to measure length and width.

RESULTS

ICCs for the gold standard, central method, and maximal method were 0.945, 0.916, and 0.844, respectively, all of which indicated excellent reliability. For all examiners, the differences in calculation from gold standard and central method were not statistically significant (P>0.05). The estimations of CSDH volume calculated by the maximal method were significantly greater than the estimates calculated by the gold standard (P<0.05).

CONCLUSIONS

This study proves that the XYZ/2 technique is a simple and reliable method of estimating CSDH volume. The "central method" in particular yielded similar results to that of the gold standard method.

Surgical outcomes by sectioning a filum terminale in patients with terminal syringomyelia

BACKGROUND

Although terminal syringomyelia suggests a tethered spinal cord, a consensus has still not been established for surgical indications, when there are no associated abnormalities or only minor associated abnormalities. We analyzed surgical outcomes of sectioning a filum terminale in patients with terminal syringomyelia to elucidate the significance of untethering surgery.

METHODS

Fifty-seven pediatric patients with terminal syringomyelia who underwent untethering via sectioning the filum terminale between 2007 and 2018 were retrospectively analyzed. Postoperative outcomes of symptoms and MRI findings were evaluated.

RESULTS

Of 57 patients, 40 had other associated abnormalities (25 with filar lipoma and 29 with low conus medullaris) that could be responsible for tethered cord. Nineteen patients had symptoms. The mean age at the time of surgery was 18 months (3-96 months). The mean follow-up period was 3.3 years (1-9 years). Preoperative symptoms improved in 9 patients (47%) after surgery. At 1 year after the surgery, the size of syringomyelia decreased in 19 (33%), increased in 4 (8%), and did not change in 34 (69%) patients. Of 28 patients who were followed up for more than 3 years, the size decreased in 17 (61%), increased in 1 (4%), and did not change in 10 (35%).

CONCLUSION

When untethering was performed by sectioning a filum terminale, the size of terminal syringomyelia decreased in more than half of patients in the long term. Sectioning the filum terminale demonstrated the possibility of radiological and clinical improvement in patients with terminal syringomyelia.

Radiologically occult cervical intradural dermal sinus tract: a case report and review of literature

We report the unusual case of a 7-month-old girl presenting with congenital cervical dermal sinus tract in which the intradural tract was not detected on preoperative imaging and was identified intraoperatively. Considering possible devastating sequelae of infection, excision of dermal sinus tract might be justified even in the case with radiologically undetected intradural tract.

Neoadjuvant chemotherapy for atypical teratoid rhabdoid tumors (AT/RTs)

PURPOSE

Atypical teratoid rhabdoid tumor (AT/RT) is a rare, clinically highly malignant tumor. The extent of the surgical resection may affect survival. However, it is often difficult to perform gross total resection (GTR) at an initial surgery because of the large tumor size and high vascularity. Neoadjuvant chemotherapy may reduce not only the size but also the vascularity. We report our experience, review the literature, and analyze its effectiveness.

METHODS

A retrospective chart review of patients who underwent neoadjuvant chemotherapy and second-look surgery was performed. Demographic data, treatment courses, changes in tumor after the chemotherapy, extent of resection and estimated blood loss (EBL) during the second-look surgery, and outcome of each children were evaluated.

RESULTS

There are 4 cases. The average age at diagnosis was 13.3 months (2-30 months). Two to 4 courses of neoadjuvant chemotherapy were performed. MRI after the chemotherapy showed reduction of tumor volume, and tumor vascularity at the second-look surgery decreased in all cases. GTR was achieved in 3 cases, and NTR in 1 case. The mean EBL/estimated blood volume (EBL/EBV) was 21.3% (1.5-39%). The mean follow-up period was 23 months (2-48 months). At the last follow-up, 2 patients were alive without recurrence of the tumor (the follow-up periods were 48 and 16 months).

CONCLUSIONS

Neoadjuvant chemotherapy for AT/RTs might reduce both tumor size and vascularity, which enabled the maximal tumor resection. It may contribute to improve the prognosis of AT/RT through facilitating the tumor resection.

Second Free Flap Surgery for Skull Base Tumors: Case Report and Literature Review

Tumors of the skull base, such as meningiomas, tend to recur. With progress in free vascularized flap surgery, an increasing number of studies are investigating skull base reconstruction with free flaps after tumor removal. In this report, we discuss the results of second free flap surgery after skull base reconstructive surgery. We retrospectively analyzed data from patients treated at our center during the period from 2013 through 2017. All four patients identified had skull base anaplastic meningioma and had undergone radiotherapy. In all cases, the flap and donor blood vessel were sourced from sites that differed from those used in the previous surgeries. No complications developed, such as cerebrospinal fluid leakage, meningitis, wound infection, wound hemorrhage, or flap necrosis. Because the first flap was found to be unviable, it was difficult to preserve and was removed. Essential points in preventing complications are anchoring at the appropriate site, pinprick testing of the created flap, and use of multilayered countermeasures to prevent cerebrospinal fluid leakage.

Emergency Superficial Temporal Artery-Superior Cerebellar Artery Bypass for the Refractory Vertebrobasilar Insufficiency with Partial Mastoidectomy

BACKGROUND

Although it is well-known that vertebrobasilar insufficiency (VBI) because of atherothrombosis with bilateral vertebral artery (VA) occlusion is resistant to medical treatment from the acute to subacute stages, the most appropriate treatment for progressive infarction at these stages remains unclear. Here, we described a patient with VBI who underwent emergency superficial temporal artery-superior cerebellar artery (STA-SCA) bypass under partial mastoidectomy after confirming mismatch between diffusion-weighted imaging (DWI) findings and clinical symptoms. The patient showed a good outcome with this approach. To our knowledge, our surgical strategy has not been previously reported.

CASE DESCRIPTION

The patient was a 71-year-old woman with progressive infarction because of atherothrombosis with bilateral VA occlusions resistant to maximum medical treatment. Emergency STA-SCA bypass under partial mastoidectomy was performed after confirming DWI findings and symptom mismatch. A good outcome was archived, and no additional cerebral infarctions were noted.

CONCLUSIONS

Emergency bypass should be considered as a treatment option for VBI that is resistant to maximal medical treatment after confirming DWI findings and symptom mismatch. Our approach involving partial mastoidectomy provides a wide and shallow operative field for STA-SCA bypass, which allows accurate bypass with good outcomes.

Suprasellar Hemangioblastoma with Reversible Edema-Like Change Along the Optic Tract: A Case Report and Literature Review

BACKGROUND

Hemangioblastomas usually occur in the cerebellum and are often a component of von Hippel-Lindau disease. Edema-like changes along the optic tract are commonly observed in association with tumors in the sellar and suprasellar regions, such as craniopharyngiomas and pituitary adenomas. Here, we describe a case of sporadic suprasellar hemangioblastoma with edema-like changes along the optic tract that completely resolved after surgery.

CASE DESCRIPTION

The patient was a 28-year-old woman with failing vision and a bitemporal hemianopia. Magnetic resonance imaging revealed a tumor accompanied by a 10-mm cyst. Fluid-attenuated inversion recovery axial magnetic resonance imaging revealed a hyperintense region along the optic tract. Other regions of the central nervous system were normal. Endoscopic transsphenoidal surgery was performed, and the histopathologic findings confirmed hemangioblastoma. Six months after surgery, the edema-like change along the optic tract had disappeared. The patient is doing well without pituitary insufficiency, pituitary hormone medications, or signs of tumor recurrence. In addition, the genetic test was negative for von Hippel-Lindau mutations.

CONCLUSIONS

When examining a patient with suprasellar tumor, clinicians must consider the possibility of hemangioblastoma. Adequate treatment can improve the edematous change and visual disturbance.

Radiological findings of transorbital penetrating intracranial injury in a child

In penetrating injuries, woods are known to be difficult to detect with radiological imaging studies, because the wood density are known to be extremely close to the value of air on CT. Adjustment of CT window and reconstruction of a 3D image from CT images allowed us to more accurately distinguish wood from air and to find the fragment of the wooden chopstick. It is particularly useful in transorbital penetrating injury.

Bilateral suboccipital approach for a giant vertebral artery aneurysm

Giant thrombosed aneurysms of the vertebral artery (VA) are difficult to treat. Moreover, marked tortuosity of the parent VA complicates determination of the surgical approach. We report the case of a 71-year-old male patient who presented with gait disturbance. Magnetic resonance imaging revealed a giant thrombosed aneurysm of approximately 4cm in diameter located in the ventral region and to the right of the medulla oblongata. Computed tomography angiography showed that the right VA had extreme tortuosity, and that the VA union was in contact with the left 7th and 8th cranial nerves. Given that the aneurysm was thrombosed and causing a mass effect, we sought to trap it. In this case, because of the tortuous VA, intravascular team considered intravascular therapy to be too difficult. We made a question mark-shaped skin incision and used a wide bilateral suboccipital approach. The VA proximal to the aneurysm was occluded with an aneurysm clip using an approach from the right of the brainstem, while the VA distal to the aneurysm was occluded using a lateral suboccipital approach. When the VA and basilar artery are atherosclerotic and extremely tortuous, the distal and proximal aspects of the aneurysm can exist on both sides of the midline. In difficult cases such as that reported here, in which a giant VA aneurysm exceeded the midline of the anterior surface of the medulla, we believe that it is useful to employ a bilateral approach from both sides of the brainstem.

Reuse of a Reversed "Bone Pad" to Perforate Incompletely Penetrated Burr Holes Created by Automatic-Releasing Cranial Perforators

BACKGROUND

It can be difficult to make complete burr holes using a perforator with automatic releasing systems in cases of a soft diploe or thick calvarial bone.

OBJECTIVE

To demonstrate the utility of a flipped "bone pad" (BP) in recovery of penetration failure when using an automatic releasing perforator.

METHODS

For craniotomy or ventricular drainage, the first step is to make 1 or more burr holes using a craniotome. Neurosurgeons sometimes incompletely penetrate the skull using the latest tools. As a countermeasure for such cases, we have developed a simple and practical method. When making a perforation using a high-speed perforator, a round bone piece we call the BP is formed just above the dura. We pulled the BP from a completed burr hole, and placed the reversed BP in position at the bottom of the incompletely perforated burr hole. The BP acted as a new hard surface, preventing the automatic releasing system from activating, and allowed the burr hole to be completed by the craniotome without the need for additional tools.

RESULTS

With this technique, we have successfully completed 6 out of 7 imperfectly perforated burr holes using a perforator with an automatic releasing system. There were no technique-related complications, such as plunging or dural laceration.

CONCLUSIONS

The method has the advantage that the BP can be obtained without drilling an additional burr hole, and can be completed without the need for increasing cost, time, or instrument usage.

Internal Carotid Artery Aneurysm Anomalously Originating from the Posterior Communicating Artery

BACKGROUND

We report a case of an internal carotid artery (ICA) aneurysm anomalously originating from the posterior communicating artery (PComA).

CASE DESCRIPTION

Preoperative radiologic findings revealed a paraclinoid carotid artery aneurysm at the level of the distal dural ring. Because of the low rupture risk, there are no treatment indications for small paraclinoid or ICA-superior hypophyseal artery unruptured aneurysms. In this case, because of the patient's age and the irregular shape of the aneurysm, treatment was considered necessary. Intraoperative findings using microscopic and endoscopic angiography showed that the aneurysm originated from the proximal branched PComA. The PComA originated from the same level as the ophthalmic artery, and the superior hypophyseal artery originated from the distal side of the PComA.

CONCLUSIONS

According to numerous reports, small incidental paraclinoid aneurysms have a lower risk of rupture and growth than PComA aneurysms. Preoperative radiologic examination of unruptured small aneurysms was performed using magnetic resonance angiography and three-dimensional computed tomography angiography. Because the ability of magnetic resonance angiography and three-dimensional computed tomography angiography to detect small branches of the ICA is inferior to digital subtraction angiography, the location of an unruptured ICA aneurysm should be evaluated with other diagnostic modalities besides magnetic resonance angiography and three-dimensional computed tomography angiography.