Semivertical Incision: An Aesthetically and Electrophysiologically Effective Mini-Incision Technique for Carpal Tunnel Decompression.

BACKGROUND The purpose of this study was to present the clinical results of our retrospective series of carpal tunnel release (CTR) operations. For these operations we used a unique type of incision, for the first time, for treatment of carpal tunnel syndrome (CTS) consisting of a 1-cm semi-vertical (SV) incision made into the wrist crease for macroscopic open CTR. MATERIAL AND METHODS This retrospective study included 114 patients (101 females and 13 males) with CTR who were operated upon in our neurosurgery clinic between December 2010 and June 2015. Patient ages ranged from 35 to 83 years (mean 55.05±12.04 years). In total, 127 hands (73 right and 54 left) were operated upon using the SV skin incision technique. After an average follow-up of 18 months (ranging from 6 to 30 months), clinical and electrophysiological (EP) evaluations were performed. RESULTS A review of the English language literature published since 1957, when Phalen first popularised the diagnosis and treatment of this disease, determined that no previous reports of the mini-open incision technique as described in our study have been published. In our retrospective patient case review, we found that after operations using the SV incision technique, statistically significant differences were detected in electromyography (EMG) improvements (p<0.01). In addition, patients who showed improvement in EMG studies (n=90) were satisfied with the result of their surgery. CONCLUSIONS Our study demonstrated that 1-cm skin SV incision was a cosmetically satisfying, fast, and safe approach to CTR that was not only clinically effective but also electrophysiologically effective.

Microsurgical resection of tumors of the lateral and third ventricles: operative corridors for difficult-to-reach lesions.

Tumors of the lateral and third ventricles are cradled on all sides by vital vascular and eloquent neural structures. Microsurgical resection, which always requires attentive planning, plays a critical role in the contemporary management of these lesions. This article provides an overview of the open microsurgical approaches to the region highlighting key clinical perspectives.

Supracerebellar transtentorial approach to the tentorial incisura and beyond.

The supracerebellar transtentorial approach via a suboccipital craniotomy provides a corridor to reach lesions of the tentorial incisura and supratentorial lesions of the posterior medial basal temporal lobe, such as lesions of the posterior parahippocampal and fusiform gyri. The supracerebellar transtentorial approach obviates the need for either retraction of eloquent cortex or a transcortical route to reach lesions in this region. We present three cases that demonstrate the utility of this approach: a left-sided tentorial meningioma with superior projection, a left-sided posterior parahippocampal cavernous malformation, and a left-sided posterior parahippocampal grade 2 oligodendroglioma. The video can be found here: https://youtu.be/OLnzUGZfUqk .

Clip reconstruction of an 8 cm giant internal carotid artery bifurcation aneurysm: microsurgical technique.

Thrombosed giant intracranial aneurysms usually present with symptoms and signs from their mass effect. Although multiple treatment options are available, direct clip reconstruction with thromboendarterectomy remains the gold standard. Here we present a 66-year-old man with seizure, aphasia and hemiparesis. Work-up revealed a giant partially thrombosed aneurysm of the internal carotid artery bifurcation with surrounding vasogenic edema. He underwent clip reconstruction of the aneurysm via a cranio-orbital approach. Although we prepared for bypass with the radial artery and/or the superficial temporal artery, we were able to clip-reconstruct the aneurysm without bypass. The patient improved upon his pre-morbid state after surgery and made an excellent recovery. The video can be found here: http://youtu.be/P_10hRQFuPo .

Microsurgical clipping of a giant vertebrobasilar junction aneurysm under hypothermic circulatory arrest.

Giant posterior circulation aneurysms pose a significant challenge to neurovascular surgeons. Among various treatment methods that have been applied individually or in combination, clipping under hypothermic circulatory arrest (HCA) is rarely used. We present a 62-year-old man who initially underwent coil occlusion of the right vertebral artery (VA) for a 2.5 cm giant vertebrobasilar junction (VBJ) aneurysm. His neurological condition had declined gradually and the aneurysm grew to 4 cm in size. The patient underwent clip reconstruction of giant VBJ aneurysm under HCA. His postoperative course was prolonged due to his preexisting neurological deficits. His preoperative Modified Rankin Score was 5, and improved postoperatively to 3 at three and six months, and to 2 at one year. The video can be found here: http://youtu.be/L53SiLV8eJY.

Microsurgical anatomy of the posterior median septum of the human spinal cord.

The aim of this study was to analyze the topographical anatomy of the dorsal spinal cord (SC) in relation to the posterior median septum (PMS). This included the course and variations in the PMS, and its relationship to and distance from other dorsal spinal landmarks. Microsurgical anatomy of the PMS was examined in 12 formalin-fixed adult cadaveric SCs. Surface landmarks such as the dorsal root entry zone (DREZ), the denticulate ligament, the architecture of the leptomeninges and pial vascular distribution were noted. The PMS was examined histologically in all spinal segments. The PMS extended most deeply at spinal segments C7 and S4. This was statistically significant for all spinal segments except C5. The PMS was shallowest at segments T4 and T6, where it was statistically significantly thinner than at any other segment. In 80% of the SCs, small blood vessels were identified that traveled in a rostrocaudal direction in the PMS. The longest distance between the PMS and the DREZ was at the C1-C4 vertebral levels and the shortest distance was at the S5 level. Prevention of deficits following a dorsal midline neurosurgical approach to deep-seated SC lesions requires careful identification of the midline of the cord. The PMS and septum define the midline on the dorsum of the SC and their accurate identification is essential for a safe midline surgical approach. In this anatomical study, we describe the surface anatomy of the dorsal SC and its relationship with the PMS, which can be used to determine a safe entry zone into the SC.

Advances in Intraarterial Chemotherapy Delivery Strategies and Blood-Brain Barrier Disruption.

Chemotherapeutics play a significant role in the management of most brain tumors. First pass effect, systemic toxicity, and more importantly, the blood-brain barrier pose significant challenges to the success of chemotherapy. Over the last 80 years, different techniques of intraarterial chemotherapy delivery have been performed in many studies but failed to become standard of care. The purpose of this article is to review the history of intraarterial drug delivery and osmotic blood-brain barrier disruption, identify the challenges for clinical translation, and identify future directions for these approaches.

A technical note on anterolateral mobilization in vertebrobasilar dolichoectasia for relief of brainstem compression.

Vascular compression of neural tissue causing neurological symptoms is a wellknown phenomenon. This is commonly seen in trigeminal neuralgia and, less commonly, in hemifacial spasm by small arteries, which can be treated by microvascular decompression. Rarely, larger arteries, such as the vertebral arteries, may compress the brainstem. This can lead to symptoms of pontine or medullary distress like hemiparesis, dysphagia, or respiratory distress. This is treated by macrovascular decompression. Due to the rare and heterogenous nature of this disease, there is no standardized approach. We describe a novel technique whereby the vertebrobasilar system is mobilized anterolaterally towards the occipital condyle with a sling to decompress the brainstem.
We report two cases of vertebrobasilar dolichoectasia causing brainstem compression. A carotid patch graft sling with anterolateral mobilization to the occipital condyle is described as a surgical nuance to macrovascular decompressive surgery. Briefly, the vertebral artery was identified and dissected away from the brainstem and the bulbar cranial nerves. Bovine pericardium graft was used to create a sling around the artery by suturing the two ends together. The sling was then fixed either to the occipital condyle using cranial plating screws or suturing to the dura of the occipital condyle.
A novel surgical technique for management of vertebrobasilar dolichoectasia causing brainstem compression with progressive neurological deterioration is reported. Anatomical location and the offending vessel should guide neurosurgeons to select the best surgical option to achieve complete decompression of the involved neural structures.

Safety of intra-arterial chemotherapy with or without osmotic blood-brain barrier disruption for the treatment of patients with brain tumors.

Background: Intra-arterial administration of chemotherapy with or without osmotic blood-brain barrier disruption enhances delivery of therapeutic agents to brain tumors. The aim of this study is to evaluate the safety of these procedures. Methods: Retrospectively collected data from a prospective database of consecutive patients with primary and metastatic brain tumors who received intra-arterial chemotherapy without osmotic blood-brain barrier disruption (IA) or intra-arterial chemotherapy with osmotic blood-brain barrier disruption (IA/OBBBD) at Oregon Health and Science University (OHSU) between December 1997 and November 2018 is reported. Chemotherapy-related complications are detailed per Common Terminology Criteria for Adverse Events (CTCAE) guidelines. Procedure-related complications are grouped as major and minor. Results: 4939 procedures (1102 IA; 3837 IA/OBBBD) were performed on 436 patients with various pathologies (primary central nervous system lymphoma [26.4%], glioblastoma [18.1%], and oligodendroglioma [14.7%]). Major procedure-related complications (IA: 12, 1%; IA/OBBBD: 27, 0.7%; P = .292) occurred in 39 procedures including 3 arterial dissections requiring intervention, 21 symptomatic strokes, 3 myocardial infarctions, 6 cervical cord injuries, and 6 deaths within 3 days. Minor procedure-related complications occurred in 330 procedures (IA: 41, 3.7%; IA/OBBBD: 289, 7.5%; P = .001). Chemotherapy-related complications with a CTCAE attribution and grade higher than 3 was seen in 359 (82.3%) patients. Conclusions: We provide safety and tolerability data from the largest cohort of consecutive patients who received IA or IA/OBBBD. Our data demonstrate that IA or IA/OBBBD safely enhance drug delivery to brain tumors and brain around the tumor.

Chronic neurological deficits in mice after perinatal hypoxia and ischemia correlate with hemispheric tissue loss and white matter injury detected by MRI.

We investigated the effects of perinatal hypoxia-ischemia (HI) on brain injury and neurological functional outcome at postnatal day (P)30 through P90. HI was induced by exposing P9 mice to 8% O(2) for 55 min using the Vannucci HI model. Following HI, mice were treated with either vehicle control or Na(+)/H(+) exchanger isoform 1 (NHE1) inhibitor HOE 642. The animals were examined by the accelerating rotarod test at P30 and the Morris water maze (MWM) test at P60. T(2)-weighted MRI was conducted at P90. Diffusion tensor imaging (DTI) was subsequently performed in ex vivo brains, followed by immunohistochemical staining for changes in myelin basic protein (MBP) and neurofilament protein expression in the corpus callosum (CC). Animals at P30 after HI showed deficits in motor and spatial learning. T(2) MRI detected a wide spectrum of brain injury in these animals. A positive linear correlation was observed between learning deficits and the degree of tissue loss in the ipsilateral hemisphere and hippocampus. Additionally, CC DTI fractional anisotropy (FA) values correlated with MBP expression. Both FA and MBP values correlated with performance on the MWM test. HOE 642-treated mice exhibited improved spatial learning and memory, and less white matter injury in the CC. These findings suggest that HI-induced cerebral atrophy and CC injury contribute to the development of deficits in learning and memory, and that inhibition of NHE1 is neuroprotective in part by reducing white matter injury. T(2)-weighted MRI and DTI are useful indicators of functional outcome after perinatal HI.

Level I to III craniofacial approaches based on Barrow classification for treatment of skull base meningiomas: surgical technique, microsurgical anatomy, and case illustrations.

OBJECT: Although craniofacial approaches to the midline skull base have been defined and surgical results have been published, clear descriptions of these complex approaches in a step-wise manner are lacking. The objective of this study is to demonstrate the surgical technique of craniofacial approaches based on Barrow classification (Levels I-III) and to study the microsurgical anatomy pertinent to these complex craniofacial approaches. METHODS: Ten adult cadaveric heads perfused with colored silicone and 24 dry human skulls were used to study the microsurgical anatomy and to demonstrate craniofacial approaches in a step-wise manner. In addition to cadaveric studies, case illustrations of anterior skull base meningiomas were presented to demonstrate the clinical application of the first 3 (Levels I-III) approaches. RESULTS: Cadaveric head dissection was performed in 10 heads using craniofacial approaches. Ethmoid and sphenoid sinuses, cribriform plate, orbit, planum sphenoidale, clivus, sellar, and parasellar regions were shown at Levels I, II, and III. In 24 human dry skulls (48 sides), a supraorbital notch (85.4%) was observed more frequently than the supraorbital foramen (14.6%). The mean distance between the supraorbital foramen notch to the midline was 21.9 mm on the right side and 21.8 mm on the left. By accepting the middle point of the nasofrontal suture as a landmark, the mean distances to the anterior ethmoidal foramen from the middle point of this suture were 32 mm on the right side and 34 mm on the left. The mean distance between the anterior and posterior ethmoidal foramina was 12.3 mm on both sides; the mean distance between the posterior ethmoidal foramen and distal opening of the optic canal was 7.1 mm on the right side and 7.3 mm on the left. CONCLUSIONS: Barrow classification is a simple and stepwise system to better understand the surgical anatomy and refine the techniques in performing these complex craniofacial approaches. On the other hand, thorough anatomical knowledge of the midline skull base and variations of the neurovascular structures is crucial to perform successful craniofacial approaches.

Microsurgical anatomy of the vein of Labbé.

OBJECTIVE: Venous drainage of the temporal lobe is of great importance in various neurosurgical and combined skull base approaches. The most significant draining vein of the temporal lobe is the inferior anastomotic vein (vein of Labbé). The purpose of this study was to examine the detailed anatomy and variations of the vein of Labbé (VL) from microsurgical perspective. METHODS: Fourteen fixed human cadaver heads (28 sides) with perfused vessels were included to define microsurgical anatomy and variations of the VL. RESULTS: The main findings of the present study were as follows: (1) drainage pattern of the VL was found to be very variable in cadaveric dissections; (2) VL drained around the sinus confluence at the tentorium in one specimen (3.5%), into the large meningeal vein in the occipital dura mater in another specimen (3.5%). The VL rarely (7%) drains into the superior petrosal sinus (SPS) which may make combined skull base approaches very difficult or impossible. CONCLUSION: Results of this study suggest that careful and thorough evaluation of the VL is of great importance, especially in surgeries combining a subtemporal route with petrosal approaches by sectioning the SPS and the tentorium.

Trigeminal Neuralgia Secondary to Compression by a Microsurgical Aneurysm Clip.

Microvascular decompression (MVD) is a common surgical technique used for treatment of trigeminal neuralgia (TN) caused by direct vascular compression of the nerve at the brainstem entry zone (BEZ). Here we report a case of a patient (status postcraniotomy for microsurgical clip obliteration of a ruptured mid-basilar artery aneurysm) who developed right-sided TN 6 years after the procedure. During MVD surgery the clip head was found to be compressing the trigeminal nerve at the BEZ, causing Type 1 TN in V3 distribution. This is consistent with the commonly held theory that a pulsatile stimulus is needed to cause TN. To our knowledge there are no previous reports in the literature of an instrument causing TN.

Acute nontraumatic subdural hematoma from ruptured accessory meningeal artery pseudoaneurysm.

BACKGROUND: Cerebral angiography including internal and external carotid artery injections is crucial in young patients with a spontaneous subdural hematoma. CASE DESCRIPTION: We present the first reported case of an accessory meningeal artery aneurysm in a 46-year-old male with a history of hypertension that led to a spontaneous nontraumatic acute subdural hematoma. A PubMed review of the literature was performed using a keyword search to identify cases examining nontraumatic spontaneous intracranial hematomas related to meningeal artery aneurysms. The literature review summarizes all published reports of middle meningeal artery aneurysms resulting in nontraumatic acute intracranial bleeds. The patient underwent successful coiling of the accessory meningeal artery. CONCLUSION: We propose endovascular treatment for accessory meningeal artery aneurysms and emphasize the utility of angiography of internal and external carotid arteries in a patient with an unexplained intracranial hematoma.

Long-Term Outcomes of Intra-Arterial Chemotherapy for Progressive or Unresectable Pilocytic Astrocytomas: Case Studies.

BACKGROUND: Progressive and/or unresectable pilocytic astrocytomas (PAs) carry a poor prognosis compared to typical PA. Early radiotherapy (RT) may have severe long-term neurocognitive side effects in this patient population. Intra-arterial (IA) chemotherapy is a viable alternative or addition to intravenous (IV) chemotherapy, which may be beneficial in avoidance of early RT. OBJECTIVE: To evaluate the safety and efficacy of IA chemotherapy in this subset of patients. METHODS: This is a retrospective review of medical records of PA patients who are treated with IA chemotherapy at Oregon Health & Science University from 1997 until 2019. Response to treatment was categorized as complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD). Progression free survival (PFS) and overall survival (OS) are also reported. RESULTS: Twelve patients were identified. All patients experienced progression prior to initiation of IA chemotherapy. The most common grade 3 or 4 toxicities related to chemotherapy were thrombocytopenia (66%), neutropenia (66%), leukopenia (50%), anemia (33%), and lymphopenia (16%). Responses achieved were CR in 1, PR in 3, SD in 7, and PD in 1. Median PFS and median OS were 16.5 and 83.5 mo, respectively. A total of 112 procedures (IA injections) were performed and 250 arteries were catheterized. There were 3 minor and no major complications attributable to procedures. CONCLUSION: This study demonstrates that IA chemotherapy can be safely used in patients with unresectable or progressive PA.

Arteriovenous Malformation Presenting as Symptomatic, Enlarging and Contrast-Enhancing Mass 12 Years After Being Treated with Embolization and Radiotherapy.

BACKGROUND: Gross total resection of arteriovenous malformations (AVMs) of the central nervous system confirmed by formal angiography is accepted as a cure for patients. In some cases, this may not be possible. Even though in these cases other treatment modalities such as endovascular embolization and radiotherapy can be used, long-term follow-up is lacking in the literature. CASE DESCRIPTION: Here we report a case of a 57-year-old woman with history of a right-sided parieto-occipital/periatrial AVM, initially treated with a combination of endovascular embolization and radiotherapy. CONCLUSIONS: The patient subsequently presented (12 years later) with a symptomatic, enlarging, contrast-enhancing mass at the same location that was angiographically occult but ultimately proven to be an AVM on a background of reactive changes on pathology.

Operating microscopes: past, present, and future.

The operating microscope is a fixture of modern surgical facilities, and it is a critically important factor in the success of many of the most complex and difficult surgical interventions used in medicine today. The rise of this key surgical tool reflects advances in understanding the principles of optics and vision that have occurred over centuries. The development of reading spectacles in the late 13th century led to the construction of early compound microscopes in the 16th and 17th centuries by Lippershey, Janssen, Galileo, Hooke, and others. Perhaps surprisingly, Leeuwenhoek's simple microscopes of this era offered improved performance over his contemporaries' designs. The intervening years saw improvements that reduced the spherical and chromatic aberrations present in compound microscopes. By the late 19th century, Carl Zeiss and Ernst Abbe ushered the compound microscope into the beginnings of the modern era of commercial design and production. The introduction of the microscope into the operating room by Nylén in 1921 initiated a revolution in surgical practice that gained momentum throughout the 1950s with multiple refinements, the introduction of the Zeiss OPMI series, and Kurze's application of the microscope to neurosurgery in 1957. Many of the refinements of the last 50 years have greatly improved the handling and practical operation of the surgical microscope, considerations which are equally important to its optical performance. Today's sophisticated operating microscopes allow for advanced real-time angiographic and tumor imaging. In this paper the authors discuss what might be found in the operating rooms of tomorrow.

A vermian artery originating from the posterior cerebral artery: an anatomical case report.

During the dissection of a posterior fossa in a cadaveric head, we found a solitary superior vermian artery (VA) originating from the posterior cerebral artery (PCA). On the right side, the VA arose from the precommunicating segment of the PCA. The VA distributed by giving off some branches to the interpeduncular fossa, cerebral peduncle, midbrain, cerebellar cortex, inferior colliculus, lingula, vermis and superior medullary velum. The right superior cerebellar artery (SCA) had a normal origin from the basilar artery (BA) and supplied the righ tentorial surface of the cerebellum by means of bifurcating into two major trunks. The left SCA had duplicated origin from the BA.

The work horse of skull base surgery: orbitozygomatic approach. Technique, modifications, and applications.

OBJECT: The aim of this study was to describe the microsurgical anatomy of the orbitozygomatic craniotomy and its modifications, and detail the stepwise dissection of the temporalis fascia and muscle and explain the craniotomy techniques involved in these approaches. METHODS: Nine cadaveric embalmed heads injected with colored silicone were used to demonstrate a stepwise dissection of the 3 variations of orbitozygomatic craniotomy. The craniotomies and dissections were performed with standard surgical instruments, and the microsurgical anatomy was studied under microscopic magnification and illumination. RESULTS: The authors performed 2-piece, 1-piece, and supraorbital orbitozygomatic craniotomies in 3 cadaveric heads each. Stepwise dissection of the temporalis fascia and muscle, and osteotomy cuts were shown and the relevant microsurgical anatomy of the anterior and middle fossae was demonstrated in cadaveric heads. Surgical case examples were also presented to demonstrate the application of and indications for the orbitozygomatic approach. CONCLUSIONS: The orbitozygomatic approach provides access to the anterior and middle cranial fossae as well as the deep sellar and basilar apex regions. Increased bone removal from the skull base obviates the need for vigorous brain retraction and offers an improved multiangled trajectory and shallower operative field. Modifications to the orbitozygomatic approach provide alternatives that can be tailored to particular lesions, enabling the surgeon to use the best technique in each individual case rather than a "one size fits all" approach.

Minimizing Retraction by Pia-Arachnoidal 10-0 Sutures in Intrasulcal Dissection.

BACKGROUND: In contemporary microneurosurgery reducing retraction-induced injury to the brain is essential. Self-retaining retractor systems are commonly used to improve visualization and decrease the repetitive microtrauma, but sometimes self-retaining retractor systems can be cumbersome and the force applied can cause focal ischemia or contusions. This may increase the morbidity and mortality. Here, we describe a technique of retraction using 10-0 sutures in the arachnoid. OBJECTIVE: To evaluate the imaging and clinical results in patients where 10-0 suture retraction was used to aid the surgical procedure. METHODS: Adjacent cortex was retracted by placing 10-0 nylon suture in the arachnoid of the bank or banks of the sulcus. The suture was secured to the adjacent dural edge by using aneurysm clips, allowing for easy adjustability of the amount of retraction. We retrospectively analyzed the neurological outcome, signal changes in postoperative imaging, and ease of performing surgery in 31 patients with various intracranial lesions including intracranial aneurysms, intra- and extra-axial tumors, and cerebral ischemia requiring arterial bypass. RESULTS: Clinically, there were no injuries, vascular events, or neurological deficits referable to the relevant cortex. Postoperative imaging did not show changes consistent with ischemia or contusion due to the retraction. This technique improved the visualization and illumination of the surgical field in all cases. CONCLUSION: Retraction of the arachnoid can be used safely in cases where trans-sulcal dissection is required. This technique may improve initial visualization and decrease the need for dynamic or static retraction.