Author: cba

Posted on

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.

Posted on

Three-Dimensional Topographic Fiber Tract Anatomy of the Cerebrum

Three-Dimensional Topographic Fiber Tract Anatomy of the Cerebrum

Neurosurgery 11:274–305, 2015

The fiber tracts of the cerebrum may be a more important determinant of resection limits than the cortex. Better knowledge of the 3-dimensional (3-D) anatomic organization of the fiber pathways is important in planning safe and accurate surgery for lesions within the cerebrum.

OBJECTIVE: To examine the topographic anatomy of fiber tracts and subcortical gray matter of the human cerebrum and their relationships with consistent cortical, ventricular, and nuclear landmarks.

METHODS: Twenty-five formalin-fixed human brains and 4 whole cadaveric heads were examined by fiber dissection technique and ·6 to ·40 magnification. The fiber tracts and central core structures, including the insula and basal ganglia, were examined and their relationships captured in 3-D photography. The depth between the surface of the cortical gyri and selected fiber tracts was measured.

RESULTS: The topographic relationships of the important association, projection, and commissural fasciculi within the cerebrum and superficial cortical landmarks were identified. Important landmarks with consistent relationships to the fiber tracts were the cortical gyri and sulci, limiting sulci of the insula, nuclear masses in the central core, and lateral ventricles. The fiber tracts were also organized in a consistent pattern in relation to each other. The anatomic findings are briefly compared with functional data from clinicoradiological analysis and intraoperative stimulation of fiber tracts.

CONCLUSION: An understanding of the 3-D anatomic organization of the fiber tracts of the brain is essential in planning safe and accurate cerebral surgery.

Posted on

Fluorescein sodium-guided resection of cerebral metastases — experience with the first 30 patients

Fluorescein sodium-guided resection of cerebral metastases — experience with the first 30 patients

Acta Neurochir (2015) 157:899–904

Surgical resection is a key element of the multidisciplinary treatment of cerebral metastases (CMs). Recent studies have highlighted the importance of complete resection of CMs for improving recurrence-free and overall survival rates. This study presents the first data on the use of fluorescein sodium (FL) under the dedicated surgical microscope filter YELLOW560 nm (ZeissMeditec, Germany) in patients with CM.

Methods Thirty patients with CMs of different primary cancers were included (15 females, 15 males; mean age 61.1 years); 200 mg of FL was intravenously injected directly before CM resection. A YELLOW560 nm filter was used for microsurgical tumor resection and resection control. Surgical reports were evaluated regarding the degree of fluorescent staining, postoperative MRIs regarding the extent of resection [gadolinium (Gd)-enhanced T1-weighted sequence] and the postoperative courses regarding any adverse effects.

Results Most patients (90.0 %, n=27) showed bright fluorescent staining, which markedly enhanced tumor visibility. Three patients (10.0 %) (two with adenocarcinoma of the lung and one with melanoma of the skin) showed no or only insufficient FL staining. Another three patients (10.0 %) showed residual tumor tissue in the postoperative MRI examination. In two other patients, radiographic examination could not exclude the possibility of very small areas of residual tumor tissue. Thus, gross-total resection was achieved in 83.3 % (n=25) of patients. No adverse effects were registered over the postoperative course.

Conclusions FL and the YELLOW560 nm filter are safe and practical tools for the resection of CM, but further prospective research is needed to confirm that this advanced technique will improve the quality of CM resection.

Posted on

The anatomy of Meyer’s loop revisited

The anatomy of Meyer’s loop revisited

J Neurosurg 122:1253–1262, 2015

The goal in this study was to explore and further refine comprehension of the anatomical features of the temporal loop, known as Meyer’s loop.

Methods The lateral and inferior aspects of 20 previously frozen, formalin-fixed human brains were dissected under the operating microscope by using fiber microdissection.

Results A loop of the fibers in the anterior temporal region was clearly demonstrated in all dissections. This temporal loop, or Meyer’s loop, is commonly known as the anterior portion of the optic radiation. Fiber microdissection in this study, however, revealed that various projection fibers that emerge from the sublentiform portion of the internal capsule (IC-SL), which are the temporopontine fibers, occipitopontine fibers, and the posterior thalamic peduncle (which includes the optic radiation), participate in this temporal loop and become a part of the sagittal stratum. No individual optic radiation fibers could be differentiated in the temporal loop. The dissections also disclosed that the anterior extension and angulation of the temporal loop vary significantly.

Conclusions The fiber microdissection technique provides clear evidence that a loop in the anterior temporal region exists, but that this temporal loop is not formed exclusively by the optic radiation. Various projection fibers of the IC-SL, of which the optic radiation is only one of the several components, display this common course. The inherent limitations of the fiber dissection technique preclude accurate differentiation among individual fibers of the temporal loop, such as the optic radiation fibers.

Posted on

Fully Automated Targeting Using Nonrigid Image Registration Matches Accuracy and Exceeds Precision of Best Manual Approaches to Subthalamic Deep Brain Stimulation Targeting in Parkinson Disease

DBS 2 leads metal head holder

Neurosurgery 76:756–765, 2015

Finding the optimal location for the implantation of the electrode in deep brain stimulation (DBS) surgery is crucial for maximizing the therapeutic benefit to the patient. Such targeting is challenging for several reasons, including anatomic variability between patients as well as the lack of consensus about the location of the optimal target.

OBJECTIVE: To compare the performance of popular manual targeting methods against a fully automatic nonrigid image registration-based approach.

METHODS: In 71 Parkinson disease subthalamic nucleus (STN)-DBS implantations, an experienced functional neurosurgeon selected the target manually using 3 different approaches: indirect targeting using standard stereotactic coordinates, direct targeting based on the patient magnetic resonance imaging, and indirect targeting relative to the red nucleus. Targets were also automatically predicted by using a leave-one-out approach to populate the CranialVault atlas with the use of nonrigid image registration. The different targeting methods were compared against the location of the final active contact, determined through iterative clinical programming in each individual patient.

RESULTS: Targeting by using standard stereotactic coordinates corresponding to the center of the motor territory of the STN had the largest targeting error (3.69 mm), followed by direct targeting (3.44 mm), average stereotactic coordinates of active contacts from this study (3.02 mm), red nucleus-based targeting (2.75 mm), and nonrigid image registration-based automatic predictions using the CranialVault atlas (2.70 mm). The CranialVault atlas method had statistically smaller variance than all manual approaches.

CONCLUSION: Fully automatic targeting based on nonrigid image registration with the use of the CranialVault atlas is as accurate and more precise than popular manual methods for STN-DBS.

Posted on

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.

Posted on

Radiosurgery for symptomatic cavernous malformations: A multi‑institutional retrospective study in Japan

Gamma knife radiosurgery for brainstem cavernous malformations- should a patient wait for the rebleed?

Surg Neurol Int 2015;6:S249-57

A group study for symptomatic cavernous malformation (CM) treated with gamma knife (GK) surgery was performed.

Methods: A total of 298 cases collected from 23 GK centers across Japan were included. Hemorrhage was the most common manifestation, followed by seizures and neurological deficits. Most of the lesions were located in the brainstem and basal ganglia, followed by the cerebral or cerebellar hemispheres. The CMs, which had a mean diameter of 14.8 mm, were treated using GK surgery with a mean marginal dose of 14.6 Gy.

Results: In terms of hemorrhage‑free survival (HFS), a marked dissociation was confirmed between the hemorrhage and seizure groups, while no obvious difference was noted between sexes. Superficial CMs located in cerebellum or lobar regions responded to the treatment better than deeply located CMs in the basal ganglia or brainstem. No significant difference of dose‑dependent response was seen for three different ranges of marginal dose: Less than 15 Gy, between 15 and 20 Gy, and more than 20 Gy. Complications were more frequent after a marginal dose of over 15 Gy and in patients with lesions more than 15 mm in diameter. The rates of annual hemorrhage were estimated to be 7.4% during the first 2 years after radiosurgery and 2.8% thereafter. The overall hemorrhage rate after radiosurgery was 4.4%/year/patient.

Conclusion: The risk of hemorrhage is considerably reduced after GK treatment. The HFS as well as annual hemorrhage rate after GK treatment was apparently superior to that after conservative treatment for symptomatic CMs. To optimize the success of GK treatment, it is important to reduce the incidence of complications.

Posted on

Clinical factors associated with venous thromboembolism risk in patients undergoing craniotomy

Awake craniotomy for gliomas in a high-field intraoperative magnetic resonance imaging suite

J Neurosurg 122:1004–1011, 2015

Patients undergoing craniotomy are at risk for developing venous thromboembolism (VTE). The safety of anticoagulation in these patients is not clear. The authors sought to identify risk factors predictive of VTE in patients undergoing craniotomy.

METHODS The authors reviewed a national surgical quality database, the American College of Surgeons National Surgical Quality Improvement Program. Craniotomy patients were identified by current procedural terminology code. Clinical factors were analyzed to identify associations with VTE.

RESULTS Four thousand eight hundred forty-four adult patients who underwent craniotomy were identified. The rate of VTE in the cohort was 3.5%, including pulmonary embolism in 1.4% and deep venous thrombosis in 2.6%. A number of factors were found to be statistically significant in multivariate binary logistic regression analysis, including craniotomy for tumor, transfer from acute care hospital, age ≥ 60 years, dependent functional status, tumor involving the CNS, sepsis, emergency surgery, surgery time ≥ 4 hours, postoperative urinary tract infection, postoperative pneumonia, on ventilator ≥ 48 hours postoperatively, and return to the operating room. Patients were assigned a score based on how many of these factors they had (minimum score 0, maximum score 12). Increasing score was predictive of increased VTE incidence, as well as risk of mortality, and time from surgery to discharge.

CONCLUSIONS Patients undergoing craniotomy are at low risk of developing VTE, but this risk is increased by preoperative medical comorbidities and postoperative complications. The presence of more of these clinical factors is associated with progressively increased VTE risk; patients possessing a VTE Risk Score of ≥ 5 had a greater than 20-fold increased risk of VTE compared with patients with a VTE score of 0.

Posted on

Long-term Functional Outcomes and Predictors of Shunt-Dependent Hydrocephalus After Treatment of Ruptured Intracranial Aneurysms in the BRAT Trial: Revisiting the Clip vs Coil Debate

Hydrocephalus

Neurosurgery 76:608–615, 2015

Acute hydrocephalus is a well-known sequela of aneurysmal subarachnoid hemorrhage (SAH). Controversy exists about whether open microsurgical methods serve to reduce shunt dependency compared with endovascular techniques.

OBJECTIVE: To determine predictors of shunt-dependent hydrocephalus and functional outcomes after aneurysmal SAH.

METHODS: A total of 471 patients who were part of a prospective, randomized, controlled trial from 2003 to 2007 were retrospectively reviewed. All variables including demographic data, medical history, treatment, imaging, and functional outcomes were included as part of the trial. No additional variables were retrospectively collected.

RESULTS: Ultimately, 147 patients (31.2%) required a ventriculoperitoneal shunt (VPS) in our series. Age, dissecting aneurysm type, ruptured vertebrobasilar aneurysm, Fisher grade, Hunt and Hess grade, admission intraventricular hemorrhage, admission intraparenchymal hemorrhage, blood in the fourth ventricle on admission, perioperative ventriculostomy, and hemicraniectomy were significant risk factors (P < .05) associated with shunt-dependent hydrocephalus on univariate analysis. On multivariate analysis, intraventricular hemorrhage and intraparenchymal hemorrhage were independent risk factors for shunt dependency (P< .05). Clipping vs coiling treatment was not statistically associated with VPS after SAH on both univariate and multivariate analyses. Patients who did not receive a VPS at discharge had higher Glasgow Outcome Scale and Barthel Index scores and were more likely to be functionally independent and to return to work 72 months after surgery (P < .05).

CONCLUSION: There is no difference in shunt dependency after SAH among patients treated by endovascular or microsurgical means. Patients in whom shunt-dependent hydrocephalus does not develop after SAH tend to have improved long-term functional outcomes.

Posted on

Infections in patients undergoing craniotomy: risk factors associated with post-craniotomy meningitis

awake craniotomy

J Neurosurg 122:1113–1119, 2015

The authors performed a prospective study to define the prevalence and microbiological characteristics of infections in patients undergoing craniotomy and to clarify the risk factors for post-craniotomy meningitis.

Methods Patients older than 18 years who underwent nonstereotactic craniotomies between January 2006 and December 2008 were included. Demographic, clinical, laboratory, and microbiological data were systemically recorded. Patient characteristics, craniotomy type, and pre- and postoperative variables were evaluated as risk factors for meningitis

Results Three hundred thirty-four procedures were analyzed (65.6% involving male patients). Traumatic brain injury was the most common reason for craniotomy. Almost 40% of the patients developed at least 1 infection. Ventilatorassociated pneumonia (VAP) was the most common infection recorded (22.5%) and Acinetobacter spp. were isolated in 44% of the cases. Meningitis was encountered in 16 procedures (4.8%), and CSF cultures were positive for microbial growth in 100% of these cases. Gram-negative pathogens (Acinetobacter spp., Klebsiella spp., Pseudomonas aeruginosa, Enterobacter cloaceae, Proteus mirabilis) represented 88% of the pathogens. Acinetobacter and Klebsiella spp. demonstrated a high percentage of resistance in several antibiotic classes. In multivariate analysis, the risk for meningitis was independently associated with perioperative steroid use (OR 11.55, p = 0.005), CSF leak (OR 48.03, p < 0.001), and ventricular drainage (OR 70.52, p < 0.001).

Conclusions: Device-related postoperative communication between the CSF and the environment, CSF leak, and perioperative steroid use were defined as risk factors for meningitis in this study. Ventilator-associated pneumonia was the most common infection overall. The offending pathogens presented a high level of resistance to several antibiotics.

Posted on

Treatment Outcomes of Unruptured Arteriovenous Malformations With a Subgroup Analysis of ARUBA Eligible Patients

AVM

Neurosurgery 76:563–570, 2015

The design and conclusions of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial are controversial, and its structure limits analysis of patients who could potentially benefit from treatment.

OBJECTIVE: To analyze the results of a consecutive series of patients with unruptured brain arteriovenous malformations (BAVMs), including a subgroup analysis of ARUBAeligible patients.

METHODS: One hundred five patients with unruptured BAVMs were treated over an 8-year period. From this series, 90 adult patients and a subgroup of 61 patients determined to be ARUBA eligible were retrospectively reviewed. A subgroup analysis for Spetzler-Martin grades I/II, III, and IV/V was performed. The modified Rankin Scale was used to assess functional outcome.

RESULTS: Persistent deficits, modified Rankin Scale score deterioration, and impaired functional outcome occurred less frequently in ARUBA-eligible grade I/II patients compared with grade III to V patients combined (P = .04, P = .04, P = .03, respectively). Twenty-two of 39 patients (56%) unruptured grade I and II BAVMs were treated with surgery without and with preoperative embolization, and all had a modified Rankin Scale score of 0 to 1 at the last follow-up. All patients treated with surgery without and with preoperative embolization had radiographic cure at the last follow-up.

CONCLUSION: The results of ARUBA-eligible and unruptured grade I/II patients overall show that excellent outcomes can be obtained in this subgroup of patients, especially with surgical management. Functional outcomes for ARUBA-eligible patients were similar to those of patients who were randomized to medical management in ARUBA. On the basis of these data, in appropriately selected patients, we recommend treatment for low-grade BAVMs.

Posted on

The cranial orbital buttress technique for nonsyndromic unicoronal and metopic craniosynostosis

The cranial orbital buttress technique for nonsyndromic unicoronal and metopic craniosynostosis

Neurosurg Focus 38 (5):E4, 2015

Current craniosynostosis procedures can result in complications due to absorbable plates and screws or other specialized expensive hardware. The authors propose the cranial orbital buttress (COB) technique of frontoorbital remodeling for metopic and unicoronal synostoses, wherein no plates or screws are used. They hypothesize that, with this technique, aesthetically acceptable outcomes for unicoronal and metopic synostosis can be achieved. In this article, they present this technique and compare the results with current frontoorbital remodeling practices.

METHODS The authors conducted a retrospective chart review of cases in which patients with nonsyndromic unicoronal or metopic synostosis underwent cranio-orbital surgery at their institution from 1985 through 2009. Operative parameters, surgical variations, and complications were analyzed. The COB technique uses a 1-piece switch, hemiforeheads, or multiple pieces for forehead remodeling. The supraorbital bar is reconstructed in patients with metopic synostosis using a double wedge or greenstick fracture technique, and in patients with unicoronal synostosis a hinge procedure based on a 1.5-orbital osteotomy is used. The supraorbital bar is advanced and supported in place by bone graft(s) inserted at the lateral aspect(s) of the orbit(s) to form a buttress, with fixation done using absorbable sutures.

RESULTS A total of 79 cases met the criteria for inclusion in the study. Twenty-nine patients had metopic synostosis, 3 had combined metopic and sagittal synostoses, and 47 had unicoronal synostosis. The patients’ mean age at surgery was 11.4 ± 10.1 months and the mean operative time was 183.4 ± 41.0 minutes. The mean length of hospital stay was 3.7 ± 1.2 days. The mean blood loss was 150.0 ± 125.6 ml, and 33% of patients required a blood transfusion (mean volume 206.9 ± 102.3 ml). In metopic synostosis, hemiforeheads were used most often (24/29, 83%), and the supraorbital bar was remodeled using a bilateral intracranial orbital osteotomy followed by a double wedge modification (23/29,79%) or a greenstick fracture (4/29 14%) for milder cases. Forehead remodeling for unicoronal synostosis was by a forehead switch (39/47, 83%) and the supraorbital bar was remodeled using a 1.5-orbital intracranial orbital osteotomy (34/47, 72%) such that the bar was advanced on the abnormal side and hinged at the midline of the normal orbit. Perioperative complications occurred in 19% of cases and included dural tears (16%), inconsequential subdural hematoma (1.3%), and nasal greenstick fracture (1.3%). The total reoperation rate was 7.6% (cranioplasties for irregular contours, 6.3%; scar revision, 1.3%).

CONCLUSIONS The COB remodeling technique is simple and efficient, gives acceptable outcomes, and is less resource intensive than previous techniques reported in the literature.

Posted on

Long-term Outcomes of the US FDA IDE Prospective, Randomized Controlled Clinical Trial Comparing PCM Cervical Disc Arthroplasty With Anterior Cervical Discectomy and Fusion”

PCM vs ACDF

Spine 2015;40:674–683

Study Design. Prospective, multicenter, randomized clinical trial.

Objective. To evaluate the long-term safety and effectiveness of the PCM Cervical Disc compared with anterior cervical discectomy and fusion (ACDF) in treatment of patients with symptomatic single- level degenerative spondylosis between C3–C4 and C7–T1 with or without prior cervical fusion.

Summary of Background Data. The 2-year results of the PCM Cervical Disc trial have been reported previously. The current study reports the long-term results of the same trial.

Methods. Patients with single-level cervical spondylosis and radiculopathy with or without myelopathy unresponsive to nonoperative treatment were enrolled. The per protocol patient sample at 5 years included 293 patients (163 PCM, 130 ACDF). Adverse events and secondary surgical procedures are reported on the cohorts through current follow-up, which include 110 patients (68 PCM, 42 ACDF) at 7 years.

Results. At 5 years postoperative, all patient-reported outcomes— neck and arm pain visual analogue scale score, neck disability index, and general health (36-Item Short Form Health Survey physical and mental component scores: physical component summary, mental component summary)—were significantly improved from baselines in both groups, and mean scores were significantly better in the PCM group for neck disability index (P = 0.001), neck pain (P = 0.002), general health (Pphysical component summary= 0.014; P mental component summary= 0.004), and patient satisfaction (P = 0.005).
PCM patients trended toward fewer 2- to 7-year device-related
serious adverse events (1/214, 0.5% PCM; 2/190, 1.1% ACDF) and secondary surgical procedures (7/211, 3.3% PCM; 14/290, 7.6% ACDF). Adjacent-level degeneration was radiographically more frequent after ACDF (33.1% PCM, 50.9% ACDF; P = 0.006) and was the primary indication for the increase in late-term secondary surgical procedures after ACDF.

Conclusion. The long-term results show good clinical outcomes after ACDF and PCM arthroplasty. PCM patients showed greater improvement in neck disability index and neck pain scores with a lower rate of radiographical adjacent-level degeneration and a trend toward fewer secondary surgical procedures. These data support PCM arthroplasty to be a viable and sustainable alternative to ACDF.
Level of Evidence: 1

Posted on

Adjacent Segment Pathology Requiring Reoperation After Anterior Cervical Arthrodesis

Outcomes After Anterior Cervical Discectomy and Fusion in Professional AthletesSpine 2015;40:E571–E577

Study Design. A retrospective study.

Objective. The purpose of this study was to determine, using survivorship analysis, the rate of adjacent segment pathology (ASP) development and to identify the risk factors for reoperation.

Summary of Background Data. The study of Hilibrand defi ned “adjacent segment disease” as symptomatic radiculopathy or myelopathy due to an adjacent segment documented on 2 consecutive offi ce visits. In addition to being somewhat subjective, their criterion is not as practical as identifying the rate of adjacent pathology by the need for reoperation.

Methods. This was a retrospective analysis of 1038 consecutive patients who underwent primary anterior cervical spine arthrodesis for radiculopathy and/or myelopathy by 1 surgeon. Annual incidence and prevalence of ASP requiring surgery were calculated and survivorship was determined. We used the Cox regression for risk factor analysis.

Results. Secondary surgery on adjacent segments occurred at a relatively constant rate of 2.4% per year (95% confi dence interval, 1.9–3.0). The Kaplan-Meier analysis predicted that 22.2% of patients would need reoperation at adjacent segments by 10 years postoperatively. Factors increasing the risk were smoking, female sex, and the number of arthrodesis segments. One or 2-segment arthrodesis had an 1.8 times greater risk than arthrodesis involving 3 or more segments. Age, neurological diagnosis, diabetes, Klippel- Feil syndrome, and noncontiguous segmental-type ossifi cation of posterior longitudinal ligament were not signifi cant risks.

Conclusion. Patients treated with 1- or 2-segment anterior cervical arthrodesis are more likely to develop ASP than those treated with arthrodesis involving 3 or more segments. Smokers and women had a higher ASP reoperation rate. Our series, the largest in the literature, predicts that 22.2% of patients will require reoperation for ASP within 10 years, substantially higher than the Hilibrand study.

Level of Evidence: 3

Posted on

Silent Arteriovenous Malformation Hemorrhage and the Recognition of “Unruptured” Arteriovenous Malformation Patients Who Benefit From Surgical Intervention

Silent Arteriovenous Malformation Hemorrhage and the Recognition of “Unruptured” Arteriovenous Malformation Patients Who Benefit From Surgical Intervention

Neurosurgery 76:592–600, 201

Arteriovenous malformation (AVM) patients present in 4 ways relative to hemorrhage: (1) unruptured, without a history or radiographic evidence of old hemorrhage (EOOH); (2) silent hemorrhage, without a bleeding history but with EOOH; (3) ruptured, with acute bleeding but without EOOH; and (4) reruptured, with acute bleeding and EOOH. OBJECTIVE: We hypothesized that characteristics and outcomes in the unrecognized group of silent hemorrhage patients may differ from those of unruptured patients.

METHODS: Two hundred forty-two patients operated-on since 1997 were categorized by hemorrhage status and hemosiderin positivity in this cohort study: unruptured (group 1), silent hemorrhage (group 2), and ruptured/reruptured (group 3/4). Group 3/4 was combined because hemosiderin cannot distinguish acute hemorrhage from older silent hemorrhage.

RESULTS: Hemosiderin was found in 45% of specimens. Seventy-five patients (31.0%) had unruptured AVMs, 30 (12.4%) had silent hemorrhage, and 137 (56.6%) had ruptured/ reruptured AVMs. Deep drainage, posterior fossa location, preoperative modified Rankin Scale (mRS) score, outcome, and macrophage score were different across groups. Only the macrophage score was different between the groups without clinical hemorrhage. Outcomes were better in silent hemorrhage patients than in those with frank rupture (mean mRS scores of 1.2 and 1.7, respectively).

CONCLUSION: One-third of patients present with silent AVM hemorrhage. No clinical or anatomic features differentiate these patients from unruptured patients, except the presence of hemosiderin and macrophages. Silent hemorrhage can be diagnosed using magnetic resonance imaging with iron-sensitive imaging. Silent hemorrhage portends an aggressive natural history, and surgery halts progression to rerupture. Good final mRS outcomes and better outcomes than in those with frank rupture support surgery for silent hemorrhage patients, despite the findings of ARUBA.

Posted on

Changes in cerebrospinal fluid flow assessed using intraoperative MRI during posterior fossa decompression for Chiari malformation

Changes in cerebrospinal fluid flow assessed using intraoperative MRI during posterior fossa decompression for Chiari malformation

J Neurosurg 122:1068–1075, 2015

The authors completed a prospective, institutional review board–approved study using intraoperative MRI (iMRI) in patients undergoing posterior fossa decompression (PFD) for Chiari I malformation. The purpose of the study was to examine the utility of iMRI in determining when an adequate decompression had been performed.

Methods Patients with symptomatic Chiari I malformations with imaging findings of obstruction of the CSF space at the foramen magnum, with or without syringomyelia, were considered candidates for surgery. All patients underwent complete T1, T2, and cine MRI studies in the supine position preoperatively as a baseline. After the patient was placed prone with the neck flexed in position for surgery, iMRI was performed. The patient then underwent a bone decompression of the foramen magnum and arch of C-1, and the MRI was repeated. If obstruction was still present, then in a stepwise fashion the patient underwent dural splitting, duraplasty, and coagulation of the tonsils, with an iMRI study performed after each step guiding the decision to proceed further.

Results Eighteen patients underwent PFD for Chiari I malformations between November 2011 and February 2013; 15 prone preincision iMRIs were performed. Fourteen of these patients (93%) demonstrated significant improvement of CSF flow through the foramen magnum dorsal to the tonsils with positioning only. This improvement was so notable that changes in CSF flow as a result of the bone decompression were difficult to discern.

Conclusions The authors observed significant CSF flow changes when simply positioning the patient for surgery. These results put into question intraoperative flow assessments that suggest adequate decompression by PFD, whether by iMRI or intraoperative ultrasound. The use of intraoperative imaging during PFD for Chiari I malformation, whether by ultrasound or iMRI, is limited by CSF flow dynamics across the foramen magnum that change significantly when the patient is positioned for surgery.

Posted on

Endovascular and Surgical Treatment of Internal Carotid Bifurcation Aneurysms: Comparison of Results, Outcome, and Mid-Term Follow-up

Categorization of aneurysms by their origin and projection

Neurosurgery 76:540–551, 2015

Aneurysms of the internal carotid artery (ICA) bifurcation are rare, and no studies have compared patient outcomes after endovascular vs surgical treatment.

OBJECTIVE: To report the safety, efficacy, and follow-up outcome of these 2 treatment options for patients with ICA bifurcation aneurysms.

METHODS: Patient and aneurysm characteristics, treatment results, and follow-up outcomes (at 30 months) were analyzed from patient records and review of imaging findings.

RESULTS: A total of 58 patients with ICA bifurcation aneurysms were treated. By interdisciplinary consensus, 30 aneurysms were assigned for coiling and 28 for clipping. Patients who underwent surgical clipping were younger and had larger aneurysms. More patients were assigned to coiling if their aneurysms originated only from the ICA bifurcation or projected superiorly. For the combined angiographic endpoint, complete and nearly complete occlusion (Raymond-Roy I + II), similar rates of 96% (coiling) or 100% (clipping) could be achieved. Raymond-Roy I occlusion occurred more often after clipping (79% vs 41% coiling). Follow-up of the endovascular group showed minor recanalization of the aneurysm neck (Raymond-Roy II) in 42%. One patient (4%) showed a major recanalization (Raymond-Roy III) and needed re-treatment. For incidental findings, no bleeding complications or new persistent neurological deficits occurred during follow-up.

CONCLUSION: Treatment of ICA bifurcation aneurysms after interdisciplinary assignment to clipping or coiling is effective and safe. Despite significantly more minor recanalizations after coiling, the re-treatment rate was very low, and no bleeding was observed during follow-up. Multivariate analysis revealed that origin only from the ICA bifurcation was an independent predictor of aneurysm recanalization after endovascular treatment.

Posted on

Deep brain stimulation versus anterior capsulotomy for obsessive-compulsive disorder: a review of the literature

DBS

J Neurosurg 122:1028–1037, 2015

Obsessive-compulsive disorder (OCD) is a chronic and debilitating psychiatric condition. Traditionally, anterior capsulotomy (AC) was an established procedure for treatment of patients with refractory OCD. Over recent decades, deep brain stimulation (DBS) has gained popularity.

In this paper the authors review the published literature and compare the outcome of AC and DBS targeting of the area of the ventral capsule/ventral striatum (VC/VS) and nucleus accumbens (NAcc). Patients in published cases were grouped according to whether they received AC or DBS and according to their preoperative scores on the Yale-Brown Obsessive-Compulsive Scale (YBOCS), and then separated according to outcome measures: remission (YBOCS score < 8); response (≥ 35% improvement in YBOCS score); nonresponse (< 35% improvement in YBOCS score); and unfavorable (i.e., worsening of the baseline YBOCS score).

Twenty studies were identified reporting on 170 patients; 62 patients underwent DBS of the VC/VS or the NAcc (mean age 38 years, follow-up 19 months, baseline YBOCS score of 33), and 108 patients underwent AC (mean age 36 years, follow-up 61 months, baseline YBOCS score of 30). In patients treated with DBS there was a 40% decrease in YBOCS score, compared with a 51% decrease for those who underwent AC (p = 0.004). Patients who underwent AC were 9% more likely to go into remission than patients treated with DBS (p = 0.02). No difference in complication rates was noted.

Anterior capsulotomy is an efficient procedure for refractory OCD. Deep brain stimulation in the VC/VS and NAcc area is an emerging and promising therapy. The current popularity of DBS over ablative surgery for OCD is not due to nonefficacy of AC, but possibly because DBS is perceived as more acceptable by clinicians and patients.

Posted on

Atlantoaxial instability in acute odontoid fractures is associated with nonunion and mortality

Atlantoaxial-instability-in-acute-odontoid-fractures-is-associated-with-nonunion-and-mortality_2015_The-Spine-Journal

The Spine Journal 15 (2015) 910–917

Odontoid fractures are the most common geriatric cervical spine fractures. Nonunion rates have been reported to be up to 40% and mortality up to 35%, and poor functional outcomes are common. Atlantoaxial instability (AAI) is a plausible prognostic factor, but its role has not been previously examined.

PURPOSE: To determine the effect of severe AAI on the outcomes of nonunion and mortality in patients with acute odontoid fractures.

STUDY DESIGN: Retrospective cohort/single institution.

PATIENT SAMPLE: One hundred twenty-four consecutive patients with acute odontoid fractures.

OUTCOME MEASURES: Rates of nonunion and mortality.

METHODS: Two independent blinded reviewers measured AAI using postinjury computed tomography scans. Patients were classified as having ‘‘severe’’ or ‘‘minimal’’ AAI on the basis of greater versus less than or equal to 50% mean subluxation across each C1–C2 facet joint. Rates of nonunion and mortality were compared using independent samples t tests and adjusted for age, displacement, and subtype using binary logistic regression.

RESULTS: One hundred seven patients had minimal AAI and 17 had severe AAI. Mean follow-up was 4.4 months (standard deviation54.6). Patients with severe AAI were more likely to experience nonunion (29% vs. 10%, respectively; p5.03) and mortality (35% vs. 14%, respectively; p5.03) regardless of treatment modality. Fracture displacement correlated with AAI (r250.65). When adjusted for patient age, the odds ratio of nonunion with severe AAI approached significance at 3.3 (95% confidence interval [CI]: 0.9–11.7). Mortality prediction with AAI approached a twofold increased risk (odds ratio52.1; 95% CI: 0.6–6.8). In patients with Type-II fractures, the odds of mortality with severe AAI approached a threefold higher risk (odds ratio53.3; 95% CI: 0.9–12.3).

CONCLUSIONS: Patients with acute odontoid fractures and severe AAI may be more likely to experience nonunion and mortality, suggesting the possibility that aggressive management could be warranted. Further investigation with a large prospective study including patient-important functional outcomes is justified. 

Posted on

Does Navigated Transcranial Stimulation Increase the Accuracy of Tractography?

Does Navigated Transcranial Stimulation Increase the Accuracy of Tractography?

Neurosurgery 0:1–10, 2015

Tractography based on diffusion tensor imaging has become a popular tool for delineating white matter tracts for neurosurgical procedures.

OBJECTIVE: To explore whether navigated transcranial magnetic stimulation (nTMS) might increase the accuracy of fiber tracking.

METHODS: Tractography was performed according to both anatomic delineation of the motor cortex (n = 14) and nTMS results (n = 9). After implantation of the definitive electrode, stimulation via the electrode was performed, defining a stimulation threshold for eliciting motor evoked potentials recorded during deep brain stimulation surgery. Others have shown that of arm and leg muscles. This threshold was correlated with the shortest distance between the active electrode contact and both fiber tracks. Results were evaluated by correlation to motor evoked potential monitoring during deep brain stimulation, a surgical procedure causing hardly any brain shift.

RESULTS: Distances to fiber tracks clearly correlated with motor evoked potential thresholds. Tracks based on nTMS had a higher predictive value than tracks based on anatomic motor cortex definition (P < .001 and P = .005, respectively). However, target site, hemisphere, and active electrode contact did not influence this correlation.

CONCLUSION: The implementation of tractography based on nTMS increases the accuracy of fiber tracking. Moreover, this combination of methods has the potential to become a supplemental tool for guiding electrode implantation.

Proudly powered by WordPress