pCO(2) and pH regulation of cerebral blood flow

CO₂ serves as one of the fundamental regulators of cerebral blood flow (CBF). It is widely considered that this regulation occurs through pCO₂-driven changes in pH of the cerebral spinal fluid (CSF), with elevated and lowered pH causing direct relaxation and contraction of the smooth muscle, respectively. However, some findings also suggest that pCO₂ acts independently of and/or in conjunction with altered pH. This action may be due to a direct effect of CSF pCO₂ on the smooth muscle as well as on the endothelium, nerves, and astrocytes. Findings may also point to an action of arterial pCO₂ on the endothelium to regulate smooth muscle contractility. Thus, the effects of pH and pCO₂ may be influenced by the absence/presence of different cell types in the various experimental preparations. Results may also be influenced by experimental parameters including myogenic tone as well as solutions containing significantly altered HCO₃⁻ concentrations, i.e., solutions routinely employed to differentiate the effects of pH from pCO₂. In sum, it appears that pCO₂, independently and in conjunction with pH, may regulate CBF.

Decompressive hemicraniectomy for malignant middle cerebral artery territory infarction: is life worth living?

OBJECT

Although decompressive hemicraniectomy has been shown to reduce death and improve functional outcome following malignant middle cerebral artery territory infarction, there is ongoing debate as to whether surgery should be routinely performed, considering the very high rates of disability and functional dependence in survivors. Through a systematic review of the literature, the authors sought to determine the outcome from a patient's perspective.

METHODS

In September 2010, a MEDLINE search of the English-language literature was performed using various combinations of 12 key words. A total of 16 papers were reviewed and individual study data were extracted.

RESULTS

There was significant variability in study design, patient eligibility criteria, timing of surgery, and methods of outcome assessment. There were 382 patients (59% male, 41% female) with a mean age of 50 years, 25% with dominant-hemisphere infarction. The mortality rate was 24% and the mean follow-up in survivors was 19 months (range 3-114 months). Of 156 survivors with available modified Rankin Scale (mRS) scores, 41% had favorable functional outcome (mRS Score ≤ 3), whereas 47% had moderately severe disability (mRS Score 4). Among 157 survivors with quality of life assessment, the mean overall reduction was 45%: 67% for physical aspect and 37% for psychosocial aspect. Of 114 screened survivors, depression affected 56% and was moderate or severe in 25%. Most patients and/or caregivers (77% of the 209 interviewed) were satisfied and would give consent again for the procedure.

CONCLUSIONS

Despite high rates of physical disability and depression, the vast majority of patients are satisfied with life and do not regret having undergone surgery.

Treatment strategies for complex intracranial aneurysms: review of a 12-year experience at the university of cincinnati

Complex intracranial aneurysms (CIAs) include those classified as giant, those located in brain regions of technically difficult access, or that involve arterial trunks/branches, and/or have complicated wall structure. We reviewed retrospectively our management of such lesions in a 12-year period. From 1997 to 2009, 192 patients were admitted with CIAs (133 females, 59 males; average age 55 years); 128 presented with subarachnoid hemorrhage (SAH) and 64 with unruptured, symptomatic CIAs. The SAH group had 73 anterior- and 55 posterior-circulation aneurysms. Most frequent location was middle cerebral artery. Treatment strategies included clipping (65.6%), coiling/stenting (28.1%), bypass (3.1%), no treatment (3.1%). Coiling/stenting was exclusively used for posterior-circulation aneurysms. Outcomes were good (modified Rankin Scale [mRS] 0 to 2) in 54 patients (42.2%), fair (mRS = 3 to 4) in 38 (29.7%), and poor (mRS = 5 to 6) in 36 (28.1%). Among unruptured CIAs, there were 47 anterior- and 17 posterior-circulation aneurysms. Most frequent location was ophthalmic. Thirty (46.9%) were clipped, 19 (29.7%) coiled, 6 (9.4%) by-passed, 2 (3.1%) wrapped, and 7 (10.9%) had no treatment. Outcomes were good in 57 patients (89%) and fair in 7 (11%). Good outcomes were obtained in unruptured CIAs using a multidisciplinary approach. Ruptured CIAs carry a significantly worse prognosis than overall SAH patients.

Measuring surgical outcomes in neurosurgery: implementation, analysis, and auditing a prospective series of more than 5000 procedures

OBJECT

Health care reform debate includes discussions regarding outcomes of surgical interventions. Yet quality of medical care, when judged as a health outcome, is difficult to define because of impediments affecting accuracy in data collection, analysis, and reporting. In this prospective study, the authors report the outcomes for neurosurgical treatment based on point-of-care interactions recorded in the electronic medical record (EMR).

METHODS

The authors' neurosurgery practice collected outcome data for 19 physicians and ancillary personnel using the EMR. Data were analyzed for 5361 consecutive surgical cases, either elective or emergency procedures, performed during 2009 at multiple hospitals, offices, and an ambulatory spine surgery center. Main outcomes included complications, length of stay (LOS), and discharge disposition for all patients and for certain frequently performed procedures. Physicians, nurses, and other medical staff used validated scales to record the hospital LOS, complications, disposition at discharge, and return to work.

RESULTS

Of the 5361 surgical procedures performed, two-thirds were spinal procedures and one-third were cranial procedures. Organization-wide compliance with reporting rates of major complications improved throughout the year, from 80.7% in the first quarter to 90.3% in the fourth quarter. Auditing showed that rates of unreported complications decreased from 11% in the first quarter to 4% in the fourth quarter. Complication data were available for 4593 procedures (85.7%); of these, no complications were reported in 4367 (95.1%). Discharge dispositions reported were home in 86.2%, rehabilitation center in 8.9%, and nursing home in 2.5%. Major complications included culture-proven infection in 0.61%, CSF leak in 0.89%, reoperation within the same hospitalization in 0.38%, and new neurological deficits in 0.77%. For the commonly performed procedures, the median hospital LOS was 3 days for craniotomy for aneurysm or intraaxial tumor and less than 1 day for angiogram, anterior cervical discectomy with fusion, or lumbar discectomy.

CONCLUSIONS

With prospectively collected outcome data for more than 5000 surgeries, the authors achieved their primary end point of institution-wide compliance and data accuracy. Components of this process included staged implementation with physician pilot studies and oversight, nurse participation, point-of-service data capture, EMR form modification, data auditing, and confidential surgeon reports.

Individual patient data subgroup meta-analysis of surgery for spontaneous supratentorial intracerebral hemorrhage

BACKGROUND AND PURPOSE

By 2010 there had been 14 published trials of surgery for intracerebral hemorrhage reported in systematic reviews or to the authors, but the role and timing of operative intervention remain controversial and the practice continues to be haphazard. This study attempted to obtain individual patient data from each of the 13 studies published since 1985 to better define groups of patients that might benefit from surgery.

METHODS

Authors of identified published articles were approached by mail, e-mail, and at conferences and invited to take part in the study. Data were obtained from 8 studies (2186 cases). Individual patient data included patient's age, Glasgow Coma Score at presentation, volume and site of hematoma, presence of intraventricular hemorrhage, method of evacuation, time to randomization, and outcome.

RESULTS

Meta-analysis indicated that there was improved outcome with surgery if randomization was [corrected] undertaken within 8 hours of ictus (P=0.003), or the volume of the hematoma was 20 to 50 mL (P=0.004), or the Glasgow Coma Score was between 9 and 12 (P=0.0009), or the patient was aged between 50 and 69 years (P=0.01). In addition, there was some evidence that more superficial hematomas with no intraventricular hemorrhage might also benefit (P=0.09).

CONCLUSIONS

There is evidence that surgery is of benefit if undertaken early before the patient deteriorates. This work identifies areas for further research. Ongoing studies in subgroups of patients such as the Surgical Trial in Lobar Intracerebral Hemorrhage (STICH II) will confirm whether these interpretations can be replicated.

Abstract 185: Declining Subarachnoid Hemorrhage Case-Fatality Rates in a Population

Introduction: In the last few decades there have been several medical advances in the care of patients with subarachnoid hemorrhage (SAH). But few population-based studies (and none in the United States) have examined outcomes in the same population over time.

Methods: All SAHs among residents of the Greater Cincinnati/Northern Kentucky (GCNK) region at least 20 years of age were identified using ICD-9 codes 430-436 and verified via study physician review in four distinct study periods. An incidence rate for each time period was calculated. Baseline characteristics, including demographics, risk factors, and functional status, were ascertained, along with hospital discharge modified Rankin score and all-cause 30- and 90-day case-fatality.

Results: We identified 78 SAHs among residents of the GCNK region in 1988, 85 from 7/1993 to 6/1994, 95 in 1999, and 91 in 2005. The incidence of SAH in the four study periods (age-, race-, and sex-adjusted to the 2000 US population) was 9.4, 9.3, 10.0, and 9.0 per 100,000, respectively. Of the 349 SAHs in the study periods, 326 were diagnosed in an ED or hospital setting, while 23 were diagnosed on autopsy alone. All-cause 30- and 90-day case-fatality rates declined significantly from 1988 to 2005 ( Table ), even when all autopsy-alone cases were excluded.

Conclusions: While the incidence of SAH remained stable in this population-based region, the 30-day and 90-day case-fatality rates declined significantly. Advances in surgical and medical management, along with systems-based changes such as the emergence of neurocritical care units, have likely led to reduced case-fatality. Future studies should explore the impact of specific factors related to improved case-fatality rates.

Long-term follow-up of cervical radiographic sagittal spinal alignment after 1- and 2-level cervical corpectomy for the treatment of spondylosis of the subaxial cervical spine causing radiculomyelopathy or myelopathy: a retrospective study

Object

Few data exist regarding long-term outcomes after cervical corpectomy for spondylotic cervical myelopathy and radiculomyelopathy. In this retrospective review, long-term radiographic outcomes are reported for 130 patients after 1- or 2-level cervical corpectomy for spondylotic myelopathy or radiculomyelopathy.

Methods

Electronic medical records including clinical data and radiographic images during a 15-year period (1993–2008) were reviewed at the Cincinnati Department of Veterans Affairs Medical Center. All patients underwent radiographic follow-up for at least 12 months (range 12–156, mean 45 ± 39.3 months), as well as clinical follow-up performed by neurosurgery staff for a mean of 29.3 ± 39.6 months (range 4–156 months). Clinical parameters at surgery and last examination included the Chiles modified Japanese Orthopaedic Association (mJOA) Myelopathy Scale. Measurements included cervical spine sagittal alignment on lateral radiographs preoperatively and postoperatively, focal Cobb angles at operated levels, and C2–7 regional alignment. Statistical analysis included the Student t-test and chi-square test. Perioperative complications and additional surgery in the cervical spine were recorded.

Results

The mJOA scores improved from a mean of 11.91 ± 2.4 preoperatively to 14.9 ± 2.33 postoperatively. The mean sagittal lordosis of the C2–7 spine increased from −16.2° ± 9.2° preoperatively to −18.5° ± 11.9° at last follow-up. Focal Cobb angles averaged a slight kyphotic angulation of 4.1° ± 2.3° at latest radiographic follow-up; of note, 7 patients (5.4%), all who had cylindrical titanium mesh cages (CTMCs), showed severe kyphotic angulation (+8.4° ± 2.4°). Patients with preoperative myelopathy showed clinical improvement at follow-up. The fusion rate was 96.2%; 3 of the 5 patients with radiographic evidence of nonfusion were smokers. Patients with postoperative kyphosis had significantly more chronic neck pain (visual analog scale score >4 lasting more than 6 months) and visits related to pain (p <0.01). Those with CTMCs had higher rates of postoperative kyphosis, chronic neck pain, and visits related to pain, irrespective of the number of levels fused (p <001). At latest follow-up, although a kyphotic increase occurred in the focal cervical sagittal Cobb angles, lordosis increased in C2–7 sagittal Gore angles. Two patients (1.5%) underwent revision of the implanted graft and/or hardware, and 5 patients (3.8%) had another procedure for adjacent-level pathologies 1–9 years later (mean 4.4 ± 2.7 years).

Conclusions

Long-term follow-up data in our veteran population support cervical corpectomy as an effective, long-lasting treatment for spondylotic myelopathy of the cervical spine. Use of CTMCs without end caps was associated with statistically significant increased postoperative kyphotic angulation and chronic pain. Despite an increase in focal kyphosis over time, regional cervical sagittal lordotic alignment had increased at the latest follow-up. Further investigation will include the association of chronic neck pain and postoperative kyphosis, and high fusion rates among a veteran population of heavy smokers.

Low-dose recombinant tissue-type plasminogen activator enhances clot resolution in brain hemorrhage: the intraventricular hemorrhage thrombolysis trial

BACKGROUND AND PURPOSE

Patients with intracerebral hemorrhage and intraventricular hemorrhage have a reported mortality of 50% to 80%. We evaluated a clot lytic treatment strategy for these patients in terms of mortality, ventricular infection, and bleeding safety events, and for its effect on the rate of intraventricular clot lysis.

METHODS

Forty-eight patients were enrolled at 14 centers and randomized to treatment with 3 mg recombinant tissue-type plasminogen activator (rtPA) or placebo. Demographic characteristics, severity factors, safety outcomes (mortality, infection, bleeding), and clot resolution rates were compared in the 2 groups.

RESULTS

Severity factors, including admission Glasgow Coma Scale, intracerebral hemorrhage volume, intraventricular hemorrhage volume, and blood pressure were evenly distributed, as were adverse events, except for an increased frequency of respiratory system events in the placebo-treated group. Neither intracranial pressure nor cerebral perfusion pressure differed substantially between treatment groups on presentation, with external ventricular device closure, or during the active treatment phase. Frequency of death and ventriculitis was substantially lower than expected and bleeding events remained below the prespecified threshold for mortality (18% rtPA; 23% placebo), ventriculitis (8% rtPA; 9% placebo), symptomatic bleeding (23% rtPA; 5% placebo, which approached statistical significance; P=0.1). The median duration of dosing was 7.5 days for rtPA and 12 days for placebo. There was a significant beneficial effect of rtPA on rate of clot resolution.

CONCLUSIONS

Low-dose rtPA for the treatment of intracerebral hemorrhage with intraventricular hemorrhage has an acceptable safety profile compared to placebo and historical controls. Data from a well-designed phase III clinical trial, such as CLEAR III, will be needed to fully evaluate this treatment.

Endothelin(A)-endothelin(B) receptor cross-talk and endothelin receptor binding

BACKGROUND AND OBJECTIVE

The magnitude of inhibition of an endothelin (ET)-1 response by selective blockade of the ET(A) or ET(B) receptors can be limited by apparent compensation mediated by the unblocked receptor. While the mechanism underlying this functionally defined interaction, or 'cross-talk', is not clear, binding studies suggest an interaction between the ET receptor subtypes.

KEY FINDINGS

These binding studies are reviewed and suggest that, in general, they support the hypothesis that ET(A) and ET(B) receptor activation of intracellular signalling pathways influence ET-1 binding to these receptor subtypes.

SUMMARY

However, the relationship of these binding studies to functional effects and, thus, functional ET(A)-ET(B) receptor cross-talk, remains largely untested.

Anterior Communicating Artery Aneurysm Surgery through the Orbitopterional Approach: Long-Term Follow-Up in a Series of 75 Consecutive Patients

OBJECTIVE

In this retrospective review of prospectively collected data, we report outcomes for patients with anterior communicating artery (ACoA) aneurysms treated via the orbitopterional approach and discuss the potential impact in patient outcomes by the reduction of surgery-induced brain damage.

METHODS

We retrospectively reviewed prospectively collected data from 40 men and 35 women (mean age, 50.8 years) who underwent clipping of ACoA aneurysms through the orbitopterional approach.

RESULTS

Overall outcomes at discharge using the modified Rankin Scale were good in 52 (69.4%) patients, fair in 13 (17.3%), and poor in 10 (13.3%). At last follow-up, outcomes were good in 63 (84%) patients, fair in 6 (8%), and poor in 6 (8%). Disability included none in 53.6% patients, mild in 10%, partial in 18.8%, moderate in 8.6%, moderately severe in 1.4%, severe in 2.9%, extremely severe in 2.9%, and vegetative state in 1.4%. Overall, 74% of patients returned to work after 4 months, 83% of previously unemployed patients returned to baseline, and 25% were disabled. Complications were more frequent and severe after subarachnoid hemorrhage.

CONCLUSIONS

Long-term follow-up data present the orbitopterional approach as an attractive alternative for ACoA aneurysm surgery given the low rates of surgery-related morbidity and good patient outcomes and functionality.

Spontaneous intradural vertebral artery dissection: a single-center experience and review of the literature

OBJECTIVES

To define the natural history of spontaneous intracranial vertebral artery dissections (VADs) and to review current treatment strategies.

MATERIAL AND METHODS

We searched the MEDLINE database for all existing English and French literature on VADs through January 2008. Keywords employed were intradural/intracranial vertebral artery dissection, vertebral artery dissection, and vertebral artery dissection treatment. We also reviewed our series of patients with spontaneous VAD treated in the past 5 years. Data were collected, categorized, and analyzed.

RESULTS

In our sample of 457 patients, men were more frequently affected than women, and the mean age was 51.8 years. The majority of patients (79%) presented with subarachnoid hemorrhage (SAH). We experienced a high incidence (37%) of recurrent SAH, particularly within the first 24 hours after SAH first occurred. Angiographic fusiform dilatation and pearl-and-string lesions were the most common finding. Patients who presented with SAH fared worse than those who presented with ischemia.

CONCLUSIONS

Due to a high rate of recurrent bleeding, we concluded that early treatment by either surgical or endovascular route is indicated in patients who present with SAH secondary to spontaneous intradural VADs. Treatment decisions should take into account the site and type of dissection, vertebral artery dominance, and involvement of posterior inferior cerebellar artery.

Rotational vertebral artery occlusion in a child with multiple strokes: a case-based update

INTRODUCTION

Rotational vertebral artery occlusion (RVAO), sometimes known as "Bow hunter syndrome," is an important and diagnostically challenging cause of posterior circulation stroke in children. It is caused by impingement of osseous and/or ligamentous structures on the vertebral artery.

DISCUSSION

We review the differential diagnosis and recommended workup for posterior circulation stroke in children. The anatomical cause for pediatric RVAO is most commonly an anomalous bone formation of the rostral vertebral column. Many bony anomalies have been associated with RVAO, including the "ponticulus posticus," a common anomaly of the C1 vertebrae. The definitive diagnosis of RVAO is made with dynamic angiography, and surgical decompression of the vertebral artery prevents recurrent strokes.

ILLUSTRATIVE CASE

We report a 15-year-old boy with recurrent posterior circulation ischemic strokes caused by an anomalous ossification of the C1 vertebrae. Three-dimensional (3D) and multiplanar reconstructed CT images showed the anomalous C1 ossification, and cervicocerebral digital subtraction angiography (DSA) revealed an associated vertebral artery (VA) dissection. The patient was initially managed by head immobilization in a hard collar and anticoagulation for 3 months. After healing of the dissection that was confirmed angiographically, dynamic DSA demonstrated reversible occlusion of the VA during contralateral head turn. Surgical decompression of the VA was performed and confirmed by intra-operative DSA with head turning.

CONCLUSIONS

RVAO is an important diagnosis in children with posterior circulation stroke. Our case demonstrates the need for high clinical suspicion and careful analysis of 3D cervical spine CT images in children with posterior circulation stroke.

Do current animal models of intracerebral hemorrhage mirror the human pathology?

Although intracerebral hemorrhage (ICH) has no proven treatment, well-designed studies using animal models of ICH may lead to the development of novel therapies. We briefly review current animal models of ICH. Furthermore, we discuss how these models may be utilized and targeted to facilitate translation of preclinical findings to the clinical arena.

Results of surgical management for posterior cerebral artery aneurysms: 7-year experience in the endovascular era

PURPOSE

Unlike most posterior circulation aneurysms, posterior cerebral artery (PCA) aneurysms can be surgically approached, we believe, without significant technical difficulty or procedural morbidity. We report our recent experience to assess procedural complications and clinical outcomes for PCA aneurysms.

METHODS

In our retrospective review of 15 consecutive patients with PCA aneurysms, six patients underwent surgical treatment, six patients had endovascular coiling, (three patients from the endovascular group also underwent surgical revascularization), and three patients were treated conservatively (medical or observation) (2001-2007). Clinical records were reviewed for: patient demographics; clinical presentation; aneurysm location, size, and morphology; treatment; procedural complications; outcome (clinical and angiographic).

RESULTS

Complete aneurysm obliteration with parent vessel or bypass patency was demonstrated by intraoperative angiography in all patients. One patient died and two patients suffered procedure-related permanent neurologic injury. Considering both surgical end endovascular treatment modalities, mortality was 8.3% and permanent morbidity was 16.6%. At mean clinical follow-up of 2-96 months (15.8 +/- 10.5 months), nine of ten patients had a Glasgow Outcome Score of 4 or 5. In patients who underwent bypass procedures, computed tomographic (CT) angiography or cerebral angiography demonstrated a patent functional bypass before the PCA occlusion.

CONCLUSIONS

Our findings for these 15 patients suggest the value of a multimodality of treatments for PCA aneurysms. Revascularization of the PCA can be performed with favorable technical results and clinical outcomes when the patency of the PCA cannot be preserved.

Image-guided anatomical and morphometric study of supraorbital and transorbital minicraniotomies to the sellar and perisellar regions: comparison with standard techniques

OBJECT

Minimally invasive approaches have been proposed for the treatment of anterior cranial base pathology. Whereas earlier studies have quantified surgical exposure by referring to the opening on the surface, this cadaveric morphometric study redefines the concept of working area by examining the deep exposures afforded by several different approaches. Specifically, the authors systematically quantify and compare the operative exposure afforded by the pterional, supraorbital, and transorbital keyhole approaches to the sellar, suprasellar, and perisellar regions, including the anterior communicating artery complex.

METHODS

Pterional, supraorbital, and transorbital approaches were sequentially performed in 5 embalmed cadaveric heads on both sides. Preoperative and postoperative CT scans were obtained for frameless stereotactic navigation and measurements. Using reproducible anatomical landmarks, 6 triangles were defined to systematically measure the working area, depth of the surgical window, and angle of observation for each approach. Areas of the triangles were calculated using the Heron mathematical formula based on stereotactic navigation measurements. Ten sets of data were analyzed.

RESULTS

The pterional, supraorbital, and transorbital keyhole approaches provided progressively increasing working areas. The transorbital approach was associated with significantly increased exposure when compared with the pterional approach (p < 0.01). The transorbital approach was associated with a shallower depth of the surgical window when compared with either the supraorbital (p < 0.05) or pterional (p < 0.01) approach. The angle of basal view increased 56.6% with the transorbital approach (p < 0.001) when compared with the supraorbital approach. The transorbital route provided greater exposure on deeply located midline and contralateral structures.

CONCLUSIONS

In refining the concept of working area as deep rather than superficial in the surgical field, the authors quantified the 6 triangles whose boundaries were relative to the target structures to be exposed in the approach. The authors' morphometric findings support the use of the supraorbital and transorbital approaches as a valid alternative to the pterional approach for the treatment of sellar and perisellar pathology. The transorbital approach combines the advantages of minimal invasiveness with those of cranial base techniques.

Cubital tunnel surgery in patients with cervical radiculopathy: double crush syndrome?

To determine differences in clinical outcomes in patients harboring both cubital tunnel syndrome (CuTS) and cervical radiculopathy and the influence of the so-called double crush syndrome. Both procedures were performed in 24 patients, mean age 55 years; first group of 14 patients underwent CuTS surgery as a first procedure. Second group of 10 patients underwent anterior cervical discectomy and fusion (ACDF) then ulnar nerve release (UNR). Two patients underwent bilateral nerve surgery and six multiple cervical discectomies. Surgeries consisted in 26 nerve releases with associated external neurolysis in five, and 34 ACDF procedures, with plating in six. Clinical complaints (mean time 12 months) were sensory in 20 arms, with associated motor weakness and hypothenar atrophy involvement in another six. Electromyography changes were mild (two arms), moderate (16 arms), and severe (eight arms). Mean time of follow-up was 3 years (range 18 months-14 years). Clinical improvement was evidenced in 14 patients. Sensory nerve symptoms improved in 13 limbs in both groups and motor improvement was evident in three patients with UNR as first surgery. A comparative cohort of 20 patients with UNR but without cervical radiculopathy was studied to disclose outcome differences. Of these, 13 patients had clinical improvement. No differences were found among groups. In patients with double crush syndrome, factors that seemed to influence a poor CuTS outcome were evolution of symptoms longer than a year, history of multiple neuropathies or radiculopathies, and ACDF performed before UNR.