Category: Surgical technique

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Suture retraction technique to prevent parent vessel obstruction following aneurysm tandem clipping

Suture retraction technique to prevent parent vessel obstruction following aneurysm tandem clipping

J Neurosurg 123:472–474, 2015

With large or giant aneurysms, the use of multiple tandem clips can be essential for complete obliteration of the aneurysm. One potential disadvantage, however, is the considerable cumulative weight of these clips, which may lead to kinking of the underlying parent vessels and obstruction of flow.

The authors describe a simple technique to address this problem, guided by intraoperative blood flow measurements, in a patient with a ruptured near-giant 2.2 × 1.7–cm middle cerebral artery bifurcation aneurysm that was treated with the tandem clipping technique. A total of 11 clips were applied in a vertical stacked fashion. The cumulative weight of the clips caused kinking of the temporal M2 branch of the bifurcation with reduction of flow. A 4-0 Nurolon suture tie was applied to the hub of one of the clips and was tethered to the dura of the sphenoid ridge by a small mini-clip and reinforced by application of tissue sealant. The patient underwent intraoperative indocyanine green videoangiography as well as catheter angiography, which demonstrated complete aneurysmal obliteration and preservation of vessel branches. Postoperative angiography confirmed patency of the bifurcation vessels with mild vasospasm. The patient had a full recovery with no postoperative complications and was neurologically intact at her 6-month follow-up.

The suture retraction technique allows a simple solution to parent vessel obstruction following aneurysm tandem clipping, in conjunction with the essential guidance provided by intraoperative flow measurements.

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Awake craniotomy to maximize glioma resection: methods and technical nuances over a 27-year period

awake craniotomy

J Neurosurg 123:325–339, 2015

Awake craniotomy is currently a useful surgical approach to help identify and preserve functional areas during cortical and subcortical tumor resections. Methodologies have evolved over time to maximize patient safety and minimize morbidity using this technique. The goal of this study is to analyze a single surgeon’s experience and the evolving methodology of awake language and sensorimotor mapping for glioma surgery.

Methods The authors retrospectively studied patients undergoing awake brain tumor surgery between 1986 and 2014. Operations for the initial 248 patients (1986–1997) were completed at the University of Washington, and the subsequent surgeries in 611 patients (1997–2014) were completed at the University of California, San Francisco. Perioperative risk factors and complications were assessed using the latter 611 cases.

Results The median patient age was 42 years (range 13–84 years). Sixty percent of patients had Karnofsky Performance Status (KPS) scores of 90–100, and 40% had KPS scores less than 80. Fifty-five percent of patients underwent surgery for high-grade gliomas, 42% for low-grade gliomas, 1% for metastatic lesions, and 2% for other lesions (cortical dysplasia, encephalitis, necrosis, abscess, and hemangioma). The majority of patients were in American Society of Anesthesiologists (ASA) Class 1 or 2 (mild systemic disease); however, patients with severe systemic disease were not excluded from awake brain tumor surgery and represented 15% of study participants. Laryngeal mask airway was used in 8 patients (1%) and was most commonly used for large vascular tumors with more than 2 cm of mass effect. The most common sedation regimen was propofol plus remifentanil (54%); however, 42% of patients required an adjustment to the initial sedation regimen before skin incision due to patient intolerance. Mannitol was used in 54% of cases. Twelve percent of patients were active smokers at the time of surgery, which did not impact completion of the intraoperative mapping procedure. Stimulation-induced seizures occurred in 3% of patients and were rapidly terminated with ice-cold Ringer’s solution. Preoperative seizure history and tumor location were associated with an increased incidence of stimulation- induced seizures. Mapping was aborted in 3 cases (0.5%) due to intraoperative seizures (2 cases) and patient emotional intolerance (1 case). The overall perioperative complication rate was 10%.

Conclusions Based on the current best practice described here and developed from multiple regimens used over a 27-year period, it is concluded that awake brain tumor surgery can be safely performed with extremely low complication and failure rates regardless of ASA classification; body mass index; smoking status; psychiatric or emotional history; seizure frequency and duration; and tumor site, size, and pathology.

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Single Port Optical Access Laparoscopic Shunt Insertion

Modern Paradigm for Peritoneal Catheter Insertion- Single Port Optical Access Laparoscopic Shunt Insertion
Operative Neurosurgery 11:205–212, 2015

Ventriculoperitoneal shunting is one of the most commonly performed neurosurgical procedures. Typically, for insertion of the peritoneal catheter, a mini-laparotomy technique is used. Although generally safe, it can be cosmetically undesirable and time consuming. Complications include malpositioning, bowel injury, and delayed hernias. Laparoscopic techniques have been advocated to address these issues, but have been slow to gain traction with neurosurgeons.
OBJECTIVE: To describe our experience with single port optical access laparoscopy for placement of ventriculoperitoneal shunts. Our technique simplifies adoption of a laparoscopic technique for neurosurgeons looking to incorporate its benefits.
METHODS: All ventriculoperitoneal shunts placed by the senior author since April 2011 were retrospectively reviewed. Surgical and perioperative complications, length of postoperative stay, and need for revisions were analyzed.
RESULTS: Fifty-six patients were included in the study. There were no cases of peritoneal catheter misplacement. One intraoperative complication occurred early in the series, in which there was an injury to the gallbladder necessitating cholecystectomy. There were 7 cases followed by shunt revision inclusive of the abdomen. In 3 cases, pseudocysts were noted.
CONCLUSION: Single port optical access laparoscopy is a fast and minimally invasive technique that allows direct visualization of the layers of the abdominal wall as they are traversed and visualization of the peritoneal catheter during placement. It uses a small cosmetic incision and obviates the need for postoperative abdominal radiographic studies. The procedure has a modest learning curve, but can be safely used without the assistance of an assist surgeon after the skills are acquired.

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Subtemporal transtentorial approach for recurrent trigeminal neuralgia after microvascular decompression via the lateral suboccipital approach

Subtemporal transtentorial approach for recurrent trigeminal neuralgia after microvascular decompression via the lateral suboccipital approach

J Neurosurg 122:1429–1432, 2015

Microvascular decompression (MVD) via lateral suboccipital craniotomy is the standard surgical intervention for trigeminal neuralgia (TN). For recurrent TN, difficulties are sometimes encountered when performing reoperation via the same approach because of adhesions and prosthetic materials used in the previous surgery.

In the present case report the authors describe the efficacy of the subtemporal transtentorial approach for use in recurrent TN after MVD via the lateral suboccipital approach. An 86-year-old woman, in whom an MVD via a lateral suboccipital craniotomy had previously been performed for TN, underwent surgery for recurrent TN via the subtemporal transtentorial approach, which provided excellent visualization of the neurovascular relationships and the trigeminal nerve without adhesions due to the previous surgery. Her TN disappeared after the MVD.

The present approach is ideal for visualizing the trigeminal root entry zone, and the neurovascular complex can be easily dissected using a new surgical trajectory. This approach could be another surgical option for reoperation when the previous MVD had been performed via the suboccipital approach

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Integration of Indocyanine Green Videoangiography With Operative Microscope: Augmented Reality for Interactive Assessment of Vascular Structures and Blood Flow

Integration of Indocyanine Green Videoangiography With Operative Microscope

Operative Neurosurgery 11:252–258, 2015

Preservation of adequate blood flow and exclusion of flow from lesions are key concepts of vascular neurosurgery. Indocyanine green (ICG) fluorescence videoangiography is now widely used for the intraoperative assessment of vessel patency.

OBJECTIVE: Here, we present a proof-of-concept investigation of fluorescence angiography with augmented microscopy enhancement: real-time overlay of fluorescence videoangiography within the white light field of view of conventional operative microscopy.

METHODS: The femoral artery was exposed in 7 anesthetized rats. The dissection microscope was augmented to integrate real-time electronically processed near-infrared filtered images with conventional white light images seen through the standard oculars. This was accomplished by using an integrated organic light-emitting diode display to yield superimposition of white light and processed near-infrared images. ICG solution was injected into the jugular vein, and fluorescent femoral artery flow was observed.

RESULTS: Fluorescence angiography with augmented microscopy enhancement was able to detect ICG fluorescence in a small artery of interest. Fluorescence appeared as a bright-green signal in the ocular overlaid with the anatomic image and limited to the anatomic borders of the femoral artery and its branches. Surrounding anatomic structures were clearly visualized. Observation of ICG within the vessel lumens permitted visualization of the blood flow. Recorded video loops could be reviewed in an offline mode for more detailed assessment of the vasculature.

CONCLUSION: The overlay of fluorescence videoangiography within the field of view of the white light operative microscope allows real-time assessment of the blood flow within vessels during simultaneous surgical manipulation. This technique could improve intraoperative decision making during complex neurovascular procedures.

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A Reverse-Action Clip Applier for Aneurysm Surgery

A Reverse-Action Clip Applier for Aneurysm Surgery

Operative Neurosurgery 11:230–234, 2015

Clipping is an important technique for cerebral aneurysm surgery. Although clip mechanisms and features have been refined, little attention has been paid to clip appliers. Clip closure is traditionally achieved by opening the grip of the clip applier. We reconsidered this motion and identified an important drawback, namely that the standard applier holding power decreased at the moment of clip release, which could lead to unstable clip application.

OBJECTIVE: To develop a forceps to address this clip applier design flaw.

METHODS: The new clip applier has a non–cross-type fulcrum that is closed at the time of clip release, with an action similar to that of a bipolar forceps or scissors. Thus, a surgeon can steadily apply the clip from various angles.

RESULTS: We successfully used our clip applier to treat 103 aneurysms. Although training was required to ensure smooth applier use, no difficulties associated with applier use were noted.

CONCLUSION: This clip applier can improve clipping surgery safety because it offers additional stability during clip release.

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The transmaxillary endoscopic approach to the inferior part of the orbit

The transmaxillary endoscopic approach to the inferior part

Acta Neurochir (2015) 157:625–628

Transmaxillary endoscopic approach to the inferior part of the orbit was demonstrated on cadaveric preparations; however, its clinical application has not been reported. We describe a clinically useful technique of the transmaxillary approach to the lower orbit.

Methods A four-hand technique is essential for extensive preparation within the orbit; therefore, the tools have to be introduced into the maxillary sinus through two ports: either through the canine fossa and antrostomy or through antrostomy using the bi-nostril transseptal approach.

Conclusion Intraorbital pathologies located in the inferior retrobulbar space can be successfully operated on using the transmaxillary endoscopic approach.

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Telo-velar approach to fourth-ventricle tumours: how I do it

Telo-velar approach to fourth-ventricle tumours_how I do it

Acta Neurochir (2015) 157:607–610

The “telo-velar” approach is an alternative to cerebellar splitting to gain access to the fourth ventricle through the so-called cerebello-medullary fissure (CMF).

Method In this approach, the CMF is exposed and access to the ventricle is obtained by incising the tela choroidea and inferior medullary velum. This approach enables the exploration of the entire ventricle cavity from the obex to the aqueduct.

Conclusions The exposure of the fourth ventricle is satisfactory and the floor of the fourth ventricle can be visualised early and protected. The extent of resection and outcome are satisfactory in most patients, including those with large tumours or lesions attached to the lateral or superolateral recesses of the ventricle. The deep rostral tumour attachment is the main limitation of the telo-velar approach

Key Points

• Early exposure of the interface lesion-floor of the fourth ventricle favours a safer tumour dissection.

• We feel that resection of tonsils is not necessary in the surgical setting.

• The posterior arch of C1 should be removed only if the tonsils are below the level of the foramen magnum.

• The improved access to the lateral recess of the ventricle makes the telo-velar approach particularly effective in lesions attached to cerebellar peduncles.

• The wide dissection of the cerebello-medullary fissure and gentle tonsils retraction may prevent from the occurrence of cerebellar mutism or other major cerebellar dysfunctions.

• Even the bilateral opening of the CMF does not result in cerebellar mutism if wide and cautious dissection, avoiding retraction and vascular injuries, is obtained.

• The exposure of the fourth ventricle was satisfactory also in patients harbouring lesions attached to the lateral or even the superolateral recesses of the ventricle.

• A deep rostral tumour attachment seems to be, at least in our experience, the main specific limitation of the telo-velar approach.

• The risk of hydrocephalus can be reduced by opening of the fissure bilaterally, exposing the aqueduct, and by cisterna magna-fourth ventricle communication augmentation.

• The EVD is taken in place for 48-72 h to prevent possible abrupt increase of the intracranial pressure and to favour wound closure.

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A prospective comparative study of microscope-integrated intraoperative fluorescein and indocyanine videoangiography for clip ligation of complex cerebral aneurysms

A prospective comparative study of microscope-integrated intraoperative fluorescein and indocyanine videoangiography for clip ligation of complex cerebral aneurysms

J Neurosurg 122:618–626, 2015

The authors prospectively analyzed 2 microscope-integrated videoangiography techniques using intravenous indocyanine green (ICG) and fluorescein for assessment of cerebral aneurysm obliteration and adjacent vessel patency.

Methods The authors prospectively enrolled 22 patients who underwent clip ligation of their aneurysm and used intraoperative videoangiography to assess obliteration of the aneurysmal sac and patency of the adjacent branching and perforating arteries. Patients underwent ICG videoangiography (ICG-VA) and the newly developed fluorescein videoangiography (FL-VA) using microscope-integrated fluorescence modules. Two independent observers compared the videoangiography recordings for value and quality to assess aneurysm exclusion and the patency of adjacent arteries.

Results All 22 patients first underwent FL-VA and then ICG-VA after clip application. In 7 cases (32%), FL-VA provided superior detail to assess perforating arteries (4 cases), distal branches (2 cases), and both (1 case); such detail was not readily available on ICG-VA. In 1 patient, ICG-VA offered better visualization of posterior communicating artery aneurysm occlusion than FL-VA because of staining artifact on the aneurysm dome from the adjacent tentorium. In 2 patients, FL-VA offered the needed advantage of real-time manipulation of the vessels and flow assessment by visualization through the operating microscope oculars. In 2 other cases, ICG-VA was more practical for repeat usage because of its more efficient clearance from the intravascular space. The ICG-VA image quality was often degraded at higher magnification in deep operative fields, partly due to chromatic aberration. Both ICG-VA and FL-VA afforded restricted views of vasculature based on the angle of surgical approach and obscuration by blood clot, aneurysm, or brain tissue.

Conclusions Compared with ICG-VA, FL-VA can potentially provide an improved visualization of vasculature at high magnification in deep surgical fields. ICG-VA is more effective for repeated use during clip repositioning due to ICG’s minimal vascular wall extravasation. Therefore, in certain cases, FL-VA may offer some advantages and play a complementary role along with ICG-VA in intraoperative fluorescence evaluation during microsurgical management of aneurysms.

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Novel Device and Technique for Minimally Invasive Intracerebral Hematoma Evacuation in the Same Setting of a Ruptured Intracranial Aneurysm

Novel Device and Technique for Minimally Invasive Intracerebral Hematoma Evacuation in the Same Setting of a Ruptured Intracranial Aneurysm

Operative Neurosurgery 11:43–51, 2015

The presence of intracerebral hematoma from aneurysm rupture is an indication for craniotomy for clot evacuation and aneurysm clipping. Some centers have begun securing aneurysms with coil embolization followed by clot evacuation in the operating room. This approach requires transporting a patient from the angiography suite to the operating room, which can take valuable time and resources.

OBJECTIVE: To report our experience with 3 cases in which a novel technique for minimally invasive evacuation of intracerebral hematomas after endovascular treatment of ruptured intracranial aneurysms was used. The Penumbra Apollo system can be used in the angiography suite in conjunction with neuroendovascular techniques to simultaneously address a symptomatic hematoma associated with a ruptured aneurysm.

METHODS: Standard preoperative computed tomography angiography was performed on arrival to the emergency department. The patients underwent diagnostic cerebral angiography followed by balloon-assisted coil embolization and then remained in the neurointerventional suite for intracerebral hematoma evacuation with the Apollo system.

RESULTS: All patients tolerated coil embolization and hematoma evacuation well. The combined procedures lasted <3 hours in both cases. Two patients were eventually discharged to acute rehabilitation facilities less than a month after their initial insult, and 1 has been cleared to return to work. The other patient was transferred to hospice care.

CONCLUSION: The Apollo aspiration system appears to be a safe and effective minimally invasive option for intracerebral hematoma evacuation, particularly when coupled with endovascular embolization of ruptured intracranial aneurysms. Future work will address which patient population is most likely to benefit from this promising technique.

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Classification of middle fossa floor dehiscence syndromes

Classification of middle fossa floor dehiscence syndromes

J Neurosurg 122:557–563, 2015

Middle fossa floor dehiscence (MFFD) can present as multiple syndromes depending on dehiscence location, tissue herniation, and dural integrity. The authors propose a classification system for MFFD with the potential to guide clinical decision making.

Methods A retrospective analysis of the electronic medical records (years 1995–2012) of patients who had undergone temporal craniotomy for the surgical repair of an MFFD syndrome at a single institution was undertaken. Reviewed data included demographic, operative, presentation, and outcome details. Middle fossa floor dehiscence was classified as follows: Class A, bony dehiscence without herniation of the brain and/or meninges; Class B, herniation of the brain and/or meninges through the middle fossa floor without CSF leakage; Class C, dehiscence with CSF leakage without meningitis; or Class D, dehiscence with meningitis.

Results Fifty-one patients, 22 males and 29 females, were included in the analysis. The mean age was 48.7 ± 15.5 years, mean body mass index was 32.65 ± 6.86 kg/m2, and mean symptom duration was 33 ± 42 months. Seven patients underwent repeat surgery for symptomatic recurrence; therefore, there were 58 surgical encounters. Repair included bony reconstruction with hydroxyapatite with or without resection of encephaloceles and/or repair of a dural defect. According to the MFFD classification system described, 15, 8, 27, and 8 cases were categorized as Class A, B, C, and D, respectively. The prevalence of hearing loss was 87%, 63%, and 70% in Classes A, B, and C, respectively. Vestibular symptoms were more prevalent in Class A. Seven patients reported persistent symptoms at the last follow-up. Transient complications were similar in each classification (13%–25%), and a single permanent complication related to anesthesia was observed. There were no mortalities or severe neurological morbidities in the series.

Conclusions Middle fossa floor dehiscence has a spectrum of clinical presentations. A classification system may help to clarify the diagnosis and guide therapy. Surgery, the mainstay of treatment, is safe and well tolerated.

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Extended endoscopic transsphenoidal approach infrachiasmatic corridor

EE transsphenoidal approach infrachiasmatic corridor

Neurosurg Rev (2015) 38:137–147

An extended endoscopic transsphenoidal approach is required for skull base lesions extending to the suprasellar area. Inferior approach using the infrachiasmatic corridor allows access to the lesions through the tumor growth that is favorable for the extended transsphenoidal approaches. Infrachiasmatic corridor is a safer route for the inferior approaches that is made up by basal arachnoid membrane and Liliequist’s membrane with its leaves (diencephalic and mesencephalic leaf). This area extends from the optic canal and tuberculum sella to the corpus mamillare.

We performed extended endoscopic approach using the infrachiasmatic corridor in 52 cases, including tuberculum sella meningiomas (n:23), craniopharyngiomas (n:16), suprasellar Rathke’s cleft cyst (n:6), pituitary adenoma (n:2), fibrous dysplasia (n:1), infundibular granulosa cell tumor (n:2), and epidermoid tumor (n:2). Total resection was achieved in 17 of 23 (74 %) with tuberculum sellae meningioma using infrachiasmatic approach. Twenty patients presented with visual disorders and 14 of them improved. There were two postoperative cerebrospinal fluid (CSF) leakages and one transient diabetes insipidus and one permanent diabetes insipidus. Sixteen patients were operated on by the infrachiasmatic approach for craniopharyngiomas. Improvement was reached in seven of eight patients presented with visual disorders. Complete tumor resection was performed in 10 of 16 cases and cyst aspiration in 4 cases, and there were remnants in two cases. Postoperative CSF leakage was seen in two patients.

Infrachiasmatic corridor provides an easier and safer inferior route for the removal of middle midline skull base lesions in selected cases.

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Ultrasonic Total Uncinectomy

Ultrasonic Total Uncinectomy

Operative Neurosurgery 10:535–541, 2014

In standard anterior cervical diskectomy, complete resection of the uncinate process is not commonly attempted because of the risk of injury to the vertebral artery. This may result in incomplete decompression of the nerve root when there is severe osseous foraminal stenosis.

OBJECTIVE: To demonstrate the feasibility of total uncinectomy with an ultrasonic bone dissector in patients with concomitant central and foraminal stenosis requiring anterior decompression and fusion.

METHODS: A case series of patients with cervical radiculopathy or myeloradiculopathy who underwent single-level or multilevel ultrasonic total uncinectomy (UTU) in combination with anterior cervical diskectomy and fusion is presented. The uncinate process was amputated along its base with an ultrasonic bone dissector and removed en bloc to expose the cervical root and the vertebral artery. Data gathered in accordance with routine practice were analyzed retrospectively.

RESULTS: Forty-four uncinate processes were resected in 38 patients. No UTU procedures were aborted because of technical difficulties, and no vertebral artery or nerve root injury occurred. Mean follow-up was 28 weeks (range, 14-37 weeks). Mean Neck Disability Index and Visual Analog Scale scores for neck and arm pain improved from 42%, 4.9%, and 6.8% to 23%, 2.6%, and 2.1%, respectively. Postoperative computed tomography and oblique radiographs revealed complete decompression of the neural foramen after UTU.

CONCLUSION: UTU is a safe and effective technique for complete decompression of cervical nerve roots when the coexistence of central and foraminal pathology dictates an anterior approach. The surgical technique is described in detail.

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Radical resection of nongerminomatous pineal region tumors via the occipital transtentorial approach based on arachnoidal consideration

Occipital transtentorial

Acta Neurochir (2014) 156:2253–2262

The role of radical resection for nongerminomatous pineal region tumors is still controversial. The purpose of this study was to present the surgical results in a large series and evaluate the feasibility of radical surgical strategy.

Methods We retrospectively reviewed the records of 143 patients with nongerminomatous pineal region tumors surgically treated via an occipital transtentorial approach between 2000 and 2011. The tumor was small (<2 cm) in 14.7 % of patients, medium (2–4 cm) in 52.4 %, and large (>4 cm) in 32.9 %.

Results Gross total tumor removal was achieved in 91.6 % of patients, subtotal in 7.0 %, and partial in 1.4 %. Histological diagnosis was nongerminomatous germ cell tumor in 41.3 %, pineal parenchymal tumor in 14.7 %, glial tumors in 28.7 %, and miscellaneous in 15.4 %. The overall complication and mortality rate was 18.2 % and 0.7 %, respectively. Permanent morbidity occurred in 5.6 % of patients, including hemianopsia in 3.5 % and Parinaud syndrome in 2.1 %. Hydrocephalus was resolved in 82.1 % without surgery for the CSF diversion. Sixty-eight patients with malignant tumors underwent radiotherapy; 35 also received adjuvant chemotherapy. One hundred thirty patients were successfully followed up with a mean duration of 43 months. Finally, 86.9 % of the patients achieved a favorable functional outcome (mRS≤ 2), 3.1 % had an mRS score of 3, 1.5 % had an mRS score of 4, and 8.5 % had died (mRS=6).

Conclusions Radical surgery was recommended as the optimal treatment for nongerminomatous pineal region tumors. Favorable results could be achieved by experienced neurosurgeons. Hydrocephalus could be cured by radical tumor removal in the majority of cases. The occipital transtentorial approach was indicated for most pineal region tumors, but surgeon’s preference and experience should also be considered. New understanding of the arachnoid membranes of this region may be helpful for tumor resection.

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Polyetheretherketone Implants for the Repair of Large Cranial Defects

Polyetheretherketone Implants for the Repair of Large Cranial Defects

Neurosurgery 75:523–529, 2014

Calvarial reconstruction of large cranial defects following decompressive surgery is challenging. Autologous bone cannot always be used due to infection, fragmentation, bone resorption, and other causes. Polyetheretherketone (PEEK) is a synthetic material that has many advantages in cranial-repair surgery, including strength, stiffness, durability, and inertness.

OBJECTIVE: To describe our experience with custom-made PEEK implants for the repair of large cranial defects in 3 institutions: San Francisco General Hospital, Hadassah- Hebrew University Hospital, and the National Neuroscience Institute, Singapore.

METHODS: A preoperative high-resolution computed tomography scan was obtained for each patient for design of the PEEK implant. Cranioplasty was performed via standard technique with the use of self-tapping titanium screws and miniplates.

RESULTS: Between 2006 and 2012, 66 cranioplasties with PEEK implants were performed in 65 patients (46 men, 19 women, mean age 35 6 14 years) for repair of large cranial defects. There were 5 infections of implants and 1 wound breakdown requiring removal of the implant (infection and surgical removal rates of 7.6% and 9.1%, respectively). Two patients required drainage of postoperative hematoma (overall surgical complication rate, 12.7%). Nonsurgical complications in 5 patients included seizures, nonoperative collection, and cerebrospinal fluid rhinorrhea that resolved spontaneously. Overall median patient or family satisfaction with the cranioplasty and aesthetic result was good, 4 on a scale of 5. Temporal wasting was the main aesthetic concern.

CONCLUSION: Custom-designed PEEK implants are a good option for patients with large cranial defects. The rate of complications is comparable to other implants or autologous bone. Given the large size of these defects, the aesthetic results are good.

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Endoscopic lateral orbitotomy

Endoscopic lateral orbitotomy

Acta Neurochir (2014) 156:1897–1900

Lateral orbitotomy can be minimalized using contemporary endoscopy.

Methods Anatomy of the temporal fossa/orbital wall junction is described. The attachment of the temporal fascia is cut off from the orbital rim through a 1.5 cm skin incision in the lateral orbital wrinkle. The temporal muscle is detached from the bone to create a space for the telescope. An appropriate bone opening in the lateral orbital wall is created with the aid of neuronavigation to handle intraorbital pathology.

Conclusion Endoscopic lateral orbitotomy is an original alternative to the microsurgical Krönlein approach and yields good functional and cosmetic results.

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Retrosigmoid removal of small acoustic neuroma: curative tumor removal with preservation of function

Retrosigmoid removal of small acoustic neuroma

J Neurosurg 121:554–563, 2014

Management of small acoustic neuromas (ANs) consists of 3 options: observation with imaging followup, radiosurgery, and/or tumor removal. The authors report the long-term outcomes and preservation of function after retrosigmoid tumor removal in 44 patients and clarify the management paradigm for small ANs.

Methods. A total of 44 consecutively enrolled patients with small ANs and preserved hearing underwent retrosigmoid tumor removal in an attempt to preserve hearing and facial function by use of intraoperative auditory monitoring of auditory brainstem responses (ABRs) and cochlear nerve compound action potentials (CNAPs). All patients were younger than 70 years of age, had a small AN (purely intracanalicular/cerebellopontine angle tumor ≤ 15 mm), and had serviceable hearing preoperatively. According to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology–Head and Neck Surgery Foundation, preoperative hearing levels of the 44 patients were as follows: Class A, 19 patients; Class B, 17; and Class C, 8. The surgical technique for curative tumor removal with preservation of hearing and facial function included sharp dissection and debulking of the tumor, reconstruction of the internal auditory canal, and wide removal of internal auditory canal dura.

Results. For all patients, tumors were totally removed without incidence of facial palsy, death, or other complications. Total tumor removal was confirmed by the first postoperative Gd-enhanced MRI performed 12 months after surgery. Postoperative hearing levels were Class A, 5 patients; Class B, 21; Class C, 11; and Class D, 7. Postoperatively, serviceable (Class A, B, or C) and useful (Class A or B) levels of hearing were preserved for 84% and 72% of patients, respectively. Better preoperative hearing resulted in higher rates of postoperative hearing preservation (p = 0.01); preservation rates were 95% among patients with preoperative Class A hearing, 88% among Class B, and 50% among Class C. Reliable monitoring was more frequently provided by CNAPs than by ABRs (66% vs 32%, p < 0.01), and consistently reliable auditory monitoring was significantly associated with better rates of preservation of useful hearing. Long-term follow-up by MRI with Gd administration (81 ± 43 months [range 5–181 months]; median 7 years) showed no tumor recurrence, and although the preserved hearing declined minimally over the long-term postoperative follow-up period (from 39 ± 15 dB to 45 ± 11 dB in 5.1 ± 3.1 years), 80% of useful hearing and 100% of serviceable hearing remained at the same level.

Conclusions. As a result of a surgical technique that involved sharp dissection and internal auditory canal reconstruction with intraoperative auditory monitoring, retrosigmoid removal of small ANs can lead to successful curative tumor removal without long-term recurrence and with excellent functional outcome. Thus, the authors suggest that tumor removal should be the first-line management strategy for younger patients with small ANs and preserved hearing.

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Lateral inferior cerebellar peduncle approach to dorsolateral medullary cavernous malformation

Dorsolateral medullary cavernous malformations

J Neurosurg 121:723–729, 2014

Brainstem cavernous malformations (BSCMs) present a unique therapeutic challenge to neurosurgeons. Resection of BSCMs is typically reserved for lesions that reach pial or ependymal surfaces. The current study investigates the lateral inferior cerebellar peduncle as a corridor to dorsolateral medullary BSCMs.

Methods. In this retrospective review, the authors present the cases of 4 patients (3 women and 1 man) who had a symptomatic dorsolateral cavernous malformation with radiographic and clinical evidence of hemorrhage.

Results. All patients underwent excision of the cavernous malformation via a far-lateral suboccipital craniotomy through the foramen of Luschka and with an incision in the inferior cerebellar peduncle. On intraoperative examination, 2 of the 4 patients had hemosiderin staining on the surface of the peduncle. All lesions were completely excised and all patients had a good or excellent outcome (modified Rankin Scale scores of 0 or 1).

Conclusions. This case series illustrates that intrinsic lesions of the dorsolateral medulla can be safely removed laterally through the foramen of Luschka and the inferior cerebellar peduncle.

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Transdural indocyanine green video-angiography of vascular malformations

Transdural indocyanine green video-angiography of vascular malformations

Acta Neurochir (2014) 156:1761–1767

The role of indocyanine green videoangiography (ICG-VA) in the surgical resection of vascular malformations has been largely described; conversely, the utility of ICG-VA before dural opening (transdural ICG-VA) in this situation remains unclear. The aim of this study is to present the application of transdural ICG-VA in a consecutive series of patients in order to explore the potential provided by a transdural visualisation of vascular malformations.

Method We retrospectively analysed the application of intraoperative ICG-VA before dural opening in 15 consecutive patients who underwent surgical resection of vascular malformations. The cases included 12 cerebral arterio-venous malformations (AVMs), 2 cerebral dural arterio-venous fistulas (dAVFs) and 1 spinal arterio-venous fistula (AVF).

Results ICG-VA before dural opening allowed the visualisation of the site and extension of the malformation in 13 out of 15 cases, whilst arterial feeders and venous drainages were identified in 9 out of 15 cases. In two patients with dAVF, the point of fistula could be transdurally identified through ICGVA. In 14% of cases, the size of bone flap designed on neuronavigation data was then modified according to transdural ICG-VA findings.

Conclusions Transdural ICG-VA proved an efficient tool that allows optimising the exposure of the malformation, performing a safe dural opening and identifying dural vascular connections of the lesion.

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Full endoscopic endonasal expanded approach to the petroclival region: optimizing the carotid-clival window

Full endoscopic endonasal expanded approach to the petroclival region- optimizing the carotid-clival window

Acta Neurochir (2014) 156:1627–1629

The petroclival junction (PCJ) is a challenging skull base location from neurosurgical point of view, especially if the retrocarotid space has to be reached.

Method In response to this challenge, this report provides a detailed full description of the endoscopic endonasal expanded approach (EEA) to the petroclival region and retrocarotid space. We present the technique step by step, introducing a critical concept about the optimization of the petroclival drilling, generating the carotid-clival window (CCW). The CCW is delimited by the paraclival segment of the internal carotid artery ICA anterolaterally, the petrous bone posterolaterally, the clival dura medially, the synchondrosis inferiorly, and the cavernous sinus superiorly; therefore, this approach exposes an important nuance to augment the previous approaches for PCJ and retrocarotid space.

Conclusion This technique provides a good surgical window and carries minimal risk.

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