"Push-Through" Rod Passage Technique for the Improvement of Lumbar Lordosis and Sagittal Balance in Minimally Invasive Adult Degenerative Scoliosis Surgery.

OF BACKGROUND DATA: Traditional open surgical techniques for correction of adult degenerative scoliosis (ADS) are often associated with increased blood loss, postoperative pain, and complications. Minimally invasive (MIS) techniques have been utilized to address these issues; however, concerns regarding improving certain alignment parameters have been raised. OBJECTIVE: A new "push-through" technique for MIS correction of ADS has been developed wherein a rod is bent before its placement into the screw heads and then contoured further to yield improved correction of radiographic parameters. METHODS AND STUDY DESIGN: Preoperative and postoperative radiographic measurements of 3 patients who underwent MIS correction of scoliosis using the "push-through" technique were compared with 22 prior patients who had received traditional MIS correction. All patients received staged correction of scoliosis. The first stage involved insertion of lateral lumbar interbodies. Standing x-rays were then evaluated for overall global balance. The second stage involved appropriate MIS facetectomies, facet fusions, posterior transforaminal interbodies at lower lumbar segments, and finally the placement of rods.TECHNIQUE OVERVIEW:: (1) A long rod composed of titanium is bent with a mild lordosis and passed through the extensions of the screw heads cephalad to caudad. (2) The rod is passed fully through the incision so it extrudes from the caudal end of the construct. At this point, further lordosis is bent into the rods. (3) The rod is then pulled back into the appropriate position. (4) The unnecessary cephalad rod is then cut to appropriate length with a circular saw. (5) Rod reducers are then sequentially lowered and tightened to achieve the desired correction. RESULTS: Mean age for all patients was 66.02 years. Preoperative coronal Cobb, sagittal vertical axis (SVA), and pelvic incidence (PI) were similar in all patients, whereas lumbar lordosis (LL) was smaller (15.27 vs. 29.85 degrees, P=0.00389) and pelvic tilt (PT) was larger (37.00 vs. 27.00 degrees, P=0.00011) in "push-through" patients. Postoperatively, "pushthrough" patients experienced greater correction of LL (21.93 vs. 3.70 degrees, P=0.00001), PI-LL (-18.57 vs. -0.26 degrees, P=0.00471), PT (-7.67 vs. -0.40 degrees, P=0.00341), SVA (-40.67 mm vs. 0.95 mm, P=0.05846), and coronal Cobb (-20.23 vs. -18.76 degrees, P=0.75). CONCLUSIONS: This new method of contouring a rod enables improved LL. This technique is easy to perform and can be a valuable tool in treating ADS using MIS techniques.

Cost minimization in treatment of adult degenerative scoliosis.

OBJECT: Back pain is an increasing concern for the aging population. This study aims to evaluate if minimally invasive surgery presents cost-minimization benefits compared with open surgery in treating adult degenerative scoliosis. METHODS: Seventy-one patients with adult degenerative scoliosis received 2-stage, multilevel surgical correction through either a minimally invasive spine surgery (MIS) approach with posterior instrumentation (n = 38) or an open midline (Open) approach (n = 33). Costs were derived from hospital and rehabilitation charges. Length of stay, blood loss, and radiographic outcomes were obtained from electronic medical records. Functional outcomes were measured with Oswestry Disability Index (ODI) and visual analog scale (VAS) surveys. RESULTS: Patients in both cohorts were similar in age (Age(MIS) = 65.68 yrs, Age(Open) = 63.58 yrs, p = 0.28). The mean follow-up was 18.16 months and 21.82 months for the MIS and Open cohorts, respectively (p = 0.34). MIS and Open cohorts had an average of 4.37 and 7.61 levels of fusion, respectively (p < 0.01). Total inpatient charges were lower for the MIS cohort ($269,807 vs $391,889, p < 0.01), and outpatient rehabilitation charges were similar ($41,072 vs $49,272, p = 0.48). MIS patients experienced reduced length of hospital stay (7.03 days vs 14.88 days, p < 0.01) and estimated blood loss (EBL) (EBL(MIS) = 470.26 ml, EBL(Open)= 2872.73 ml, p < 0.01). Baseline ODI scores were lower in the MIS cohort (40.03 vs 48.04, p = 0.03), and the cohorts experienced similar 1-year improvement (ΔODI(MIS) = -15.98, ΔODI(Open) = -21.96, p = 0.25). Baseline VAS scores were similar (VAS(MIS) = 6.56, VAS(Open)= 7.10, p = 0.32), but MIS patients experienced less reduction after 1 year (ΔVAS(MIS) = -3.36, ΔVAS(Open) = -4.73, p = 0.04). Preoperative sagittal vertical axis (SVA) were comparable (preoperative SVA(MIS) = 63.47 mm, preoperative SVA(Open) = 71.3 mm, p = 0.60), but MIS patients had larger postoperative SVA (postoperative SVA(MIS) = 51.17 mm, postoperative SVA(Open) = 28.17 mm, p = 0.03). CONCLUSIONS: Minimally invasive surgery demonstrated reduced costs, blood loss, and hospital stays, whereas open surgery exhibited greater improvement in VAS scores, deformity correction, and sagittal balance. Additional studies with more patients and longer follow-up will determine if MIS provides cost-minimization opportunities for treatment of adult degenerative scoliosis.

Comparison of two minimally invasive surgery strategies to treat adult spinal deformity.

OBJECT: Minimally invasive surgery (MIS) techniques are becoming a more common means of treating adult spinal deformity (ASD). The aim of this study was to compare the hybrid (HYB) surgical approach, involving minimally invasive lateral interbody fusion with open posterior instrumented fusion, to the circumferential MIS (cMIS) approach to treat ASD. METHODS: The authors performed a retrospective, multicenter study utilizing data collected in 105 patients with ASD who were treated via MIS techniques. Criteria for inclusion were age older than 45 years, coronal Cobb angle greater than 20°, and a minimum of 1 year of follow-up. Patients were stratified into 2 groups: HYB (n = 62) and cMIS (n = 43). RESULTS: The mean age was 60.7 years in the HYB group and 61.0 years in the cMIS group (p = 0.910). A mean of 3.6 interbody fusions were performed in the HYB group compared with a mean of 4.0 interbody fusions in the cMIS group (p = 0.086). Posterior fusion involved a mean of 6.9 levels in the HYB group and a mean of 5.1 levels in the cMIS group (p = 0.003). The mean follow-up was 31.3 months for the HYB group and 38.3 months for the cMIS group. The mean Oswestry Disability Index (ODI) score improved by 30.6 and 25.7, and the mean visual analog scale (VAS) scores for back/leg pain improved by 2.4/2.5 and 3.8/4.2 for the HYB and cMIS groups, respectively. There was no significant difference between groups with regard to ODI or VAS scores. For the HYB group, the lumbar coronal Cobb angle decreased by 13.5°, lumbar lordosis (LL) increased by 8.2°, sagittal vertical axis (SVA) decreased by 2.2 mm, and LL-pelvic incidence (LL-PI) mismatch decreased by 8.6°. For the cMIS group, the lumbar coronal Cobb angle decreased by 10.3°, LL improved by 3.0°, SVA increased by 2.1 mm, and LL-PI decreased by 2.2°. There were no significant differences in these radiographic parameters between groups. The complication rate, however, was higher in the HYB group (55%) than in the cMIS group (33%) (p = 0.024). CONCLUSIONS: Both HYB and cMIS approaches resulted in clinical improvement, as evidenced by decreased ODI and VAS pain scores. While there was no significant difference in degree of radiographic correction between groups, the HYB group had greater absolute improvement in degree of lumbar coronal Cobb angle correction, increased LL, decreased SVA, and decreased LL-PI. The complication rate, however, was higher with the HYB approach than with the cMIS approach.

Less invasive surgery for treating adult spinal deformities: ceiling effects for deformity correction with 3 different techniques.

OBJECT: Minimally invasive surgery (MIS) options for the treatment of adult spinal deformity (ASD) have advanced significantly over the past decade. However, a wide array of options have been described as being MIS or less invasive. In this study the authors investigated a multiinstitutional cohort of patients with ASD who were treated with less invasive methods to determine the extent of deformity correction achieved. METHODS: This study was a retrospective review of multicenter prospectively collected data in 85 consecutive patients with ASD undergoing MIS surgery. Inclusion criteria were as follows: age older than 45 years; minimum 20° coronal lumbar Cobb angle; and 1 year of follow-up. Procedures were classified as follows: 1) stand-alone (n = 7); 2) circumferential MIS (n = 43); or 3) hybrid (n = 35). RESULTS: An average of 4.2 discs (range 3-7) were fused, with a mean follow-up duration of 26.1 months in this study. For the stand-alone group the preoperative Cobb range was 22°-51°, with 57% greater than 30° and 28.6% greater than 50°. The mean Cobb angle improved from 35.7° to 30°. A ceiling effect of 23° for curve correction was observed, regardless of preoperative curve severity. For the circumferential MIS group the preoperative Cobb range was 19°-62°, with 44% greater than 30° and 5% greater than 50°. The mean Cobb angle improved from 32° to 12°. A ceiling effect of 34° for curve correction was observed. For the hybrid group the preoperative Cobb range was 23°-82°, with 74% greater than 30° and 23% greater than 50°. The mean Cobb angle improved from 43° to 15°. A ceiling effect of 55° for curve correction was observed. CONCLUSIONS: Specific procedures for treating ASD have particular limitations for scoliotic curve correction. Less invasive techniques were associated with a reduced ability to straighten the spine, particularly with advanced curves. These data can guide preoperative technique selection when treating patients with ASD.

Comparison of radiographic results after minimally invasive, hybrid, and open surgery for adult spinal deformity: a multicenter study of 184 patients.

OBJECT: Various surgical approaches, including open, minimally invasive, and hybrid techniques, have gained momentum in the management of adult spinal deformity. However, few data exist on the radiographic outcomes of different surgical techniques. The objective of this study was to compare the radiographic and clinical outcomes of the surgical techniques used in the treatment of adult spinal deformity. METHODS: The authors conducted a retrospective review of two adult spinal deformity patient databases, a prospective open surgery database and a retrospective minimally invasive surgery (MIS) and hybrid surgery database. The time frame of enrollment in this study was from 2007 to 2012. Spinal deformity patients were stratified into 3 surgery groups: MIS, hybrid surgery, and open surgery. The following pre- and postoperative radiographic parameters were assessed: lumbar major Cobb angle, lumbar lordosis, pelvic incidence minus lumbar lordosis (PI-LL), sagittal vertical axis, and pelvic tilt. Scores on the Oswestry Disability Index (ODI) and a visual analog scale (VAS) for both back and leg pain were also obtained from each patient. RESULTS: Of the 234 patients with adult spinal deformity, 184 patients had pre- and postoperative radiographs and were thus included in the study (MIS, n = 42; hybrid, n = 33; open, n = 109). Patients were a mean of 61.7 years old and had a mean body mass index of 26.9 kg/m(2). Regarding radiographic outcomes, the MIS group maintained a significantly smaller mean lumbar Cobb angle (13.1°) after surgery compared with the open group (20.4°, p = 0.002), while the hybrid group had a significantly larger lumbar curve correction (26.6°) compared with the MIS group (18.8°, p = 0.045). The mean change in the PI-LL was larger for the hybrid group (20.6°) compared with the open (10.2°, p = 0.023) and MIS groups (5.5°, p = 0.003). The mean sagittal vertical axis correction was greater for the open group (25 mm) compared with the MIS group (≤ 1 mm, p = 0.008). Patients in the open group had a significantly larger postoperative thoracic kyphosis (41.45°) compared with the MIS patients (33.5°, p = 0.005). There were no significant differences between groups in terms of pre- and postoperative mean ODI and VAS scores at the 1-year follow-up. However, patients in the MIS group had much lower estimated blood loss and transfusion rates compared with patients in the hybrid or open groups (p < 0.001). Operating room time was significantly longer with the hybrid group compared with the MIS and open groups (p < 0.001). Major complications occurred in 14% of patients in the MIS group, 14% in the hybrid group, and 45% in the open group (p = 0.032). CONCLUSIONS: This study provides valuable baseline characteristics of radiographic parameters among 3 different surgical techniques used in the treatment of adult spinal deformity. Each technique has advantages, but much like any surgical technique, the positive and negative elements must be considered when tailoring a treatment to a patient. Minimally invasive surgical techniques can result in clinical outcomes at 1 year comparable to those obtained from hybrid and open surgical techniques.

Complications, outcomes, and need for fusion after minimally invasive posterior cervical foraminotomy and microdiscectomy.

BACKGROUND CONTEXT: Posterior cervical foraminotomy (PCF) with or without microdiscectomy (posterior cervical discectomy [PCD]) is a frequently used surgical technique for cervical radiculopathy secondary to foraminal stenosis or a laterally located herniated disc. Currently, these procedures are being performed with increasing frequency using advanced minimally invasive techniques. Although the safety and efficacy of minimally invasive PCF/PCD (MI-PCF/PCD) have been established, reports on long-term outcome and need for secondary surgical intervention at the index or adjacent level are lacking. PURPOSE: To determine the rates of complications, long-term outcomes, and need for secondary surgical intervention at the index or adjacent level after MI-PCF and microdiscectomy. STUDY DESIGN: Retrospective analysis of a prospective cohort. PATIENT SAMPLE: Seventy patients treated with MI-PCF and/or MI-PCD for cervical radiculopathy. OUTCOME MEASURES: Visual Analog Scale for neck/arm (VASN/A) pain and Neck Disability Index (NDI). METHODS: Ninety-seven patients underwent MI-PCF with or without MI-PCD between 2002 and 2011. Adequate prospective follow-up was available for 70 patients (95 cervical levels). The primary outcome assessed was need for secondary surgical intervention at the index or adjacent level. The secondary outcomes assessed included complications and improvements in NDI and VASN/A scores. All complications were reviewed. Mixed-model analyses of variance with random subject effects and autoregressive first-order correlation structures were used to test for differences among NDI, VASA, and VASN measurements made over time while accounting for the correlation among repeated observations within a patient. All statistical hypothesis tests were conducted at the 5% level of significance. RESULTS: Patients were followed for a mean of 32.1 months. Of 70 patients operated, there were 3 (4.3%) complications (1 cerebrospinal fluid leak, 1 postoperative wound hematoma, and 1 radiculitis), none of which required a secondary operative intervention. Five patients required an anterior cervical discectomy and fusion (eight total levels fused) on average 44.4 months after the index surgery. Of those, five (5.3%) were at the index level and three (2.1%) were at adjacent levels. Neck Disability Index scores improved significantly (p<.0001) immediately postoperatively and continued to decrease gradually with time. Visual Analog Scale for neck/arm scores improved significantly (p<.0001) from baseline immediately postoperatively but tended to plateau with time. CONCLUSIONS: Minimally invasive PCF with or without MI-PCD is an excellent alternative for cervical radiculopathy secondary to foraminal stenosis or a laterally located herniated disc. There is a low rate (1.1% per index level per year) of future index site fusion and a very low rate (0.9% per adjacent level per year) of adjacent-level disease requiring surgery.

Primary dural repair in minimally invasive spine surgery.

We describe an effective surgical technique in primary repair of the spinal dura during minimally invasive spine surgery (MISS). Objective. Minimally invasive spine surgery includes the treatment of intradural lesions, and proper closure of the dura is necessary. However, primary dural closure can be difficult due to the restricted space of MIS retractors and the availability of appropriate surgical instrumentation. Methods. We describe the use of a needle already used in the pediatric neurosurgical arena that can facilitate easier and safer closure of spinal dura through MISS retractors in two illustrative intradural cases. Results and Discussion. The primary dural closure technique is described and patient demographics are included. The instruments specifically used for the intradural closure through MIS retractor systems include (1) 4-0 Surgilon braided nylon (Covidien, Dublin, Ireland) with a CV-20 taper 1/2 circle, 10 mm diameter needle; (2) Scanlan (Saint Paul, MN, USA) dura closure set. Conclusion. Successful primary dural repair can be performed on primary and incidental durotomies during minimally invasive spinal surgery. We describe the novel use of a 10 mm diameter needle to help surgeons safely and efficiently close the dura with more ease than previously described.

Management of intracranial hemorrhage in a child with a left ventricular assist device.

Pediatric patients bridged to heart transplant with LVADs require chronic anticoagulation and are at increased risk of hemorrhagic complications, including intracranial hemorrhage. In this population, intracranial hemorrhage is often fatal. We report a case of successful management of a five-yr-old-boy with DCM on an LVAD who developed a subdural hematoma. We initially chose medical management, weighing the patient's high risk of thromboembolism from anticoagulation reversal against the risk of his chronic subdural hematoma. When head CT showed expansion of the hemorrhage with increasing midline shift, we chose prompt surgical evacuation of the hematoma with partial reversal of anticoagulation, given the increased risk of acute deterioration. The patient ultimately received an orthotopic heart transplant and was discharged with no permanent neurological complications. This represents a case of a pediatric patient on an LVAD who survived a potentially fatal subdural hematoma and was successfully bridged to cardiac transplantation.

Convection enhanced drug delivery of BDNF through a microcannula in a rodent model to strengthen connectivity of a peripheral motor nerve bridge model to bypass spinal cord injury.

Models employing peripheral nerve to bypass spinal cord injury (SCI), although highly promising, may benefit from improved nerve regeneration and motor bridge connectivity. Recent studies have demonstrated that neuronal growth factor-induced enhancement of endogenous neurorestoration may improve neuronal connectivity after severe neurologic injury, particularly if delivered intraparenchymally with zero-order kinetics. We sought to investigate the effect of convection-enhanced delivery of brain-derived neurotrophic factor (BDNF), a neuronal growth factor, on the connectivity of a peripheral motor-nerve bridge in a rodent model using electrophysiology and immunohistochemistry (IHC). Spinal cords of 29 female rats were hemisected at the L1 level. Ipsilateral T13 peripheral nerves were dissected from their muscular targets distally, while maintaining their connections with the spinal cord, and inserted caudal to the injury site to establish the nerve bridge. A microcannula attached to a six-week mini-osmotic pump was used to deliver either BDNF (n=12), saline (n=14), or fluorescein dye (n=3) directly into the spinal cord parenchyma between the site of nerve insertion and hemisection to a depth of 2mm into the area of the lateral motor pool. After four weeks, gastrocnemius muscle activation was assessed electromyographically in five animals from each group. Spinal cords were harvested and analyzed with IHC for cannula-associated injury, and nerve regeneration. Strength of motor bridge connection was illustrated by electrophysiology data. Intraspinal BDNF levels were measured using enzyme-linked immunosorbent assay. IHC revealed increased intraparenchymal BDNF concentration at the nerve bridge insertion site with evidence of minimal trauma from cannulation. BDNF infusion resulted in stronger connections between bridge nerves and spinal motor axons. Bridge nerve electrical stimulation in BDNF-treated rats evoked hind leg electromyogram responses of shorter latency and larger amplitudes than saline-infused controls. Thus, direct convection-assisted delivery provides reliable administration of potent growth factors directly into the spinal cord parenchyma. Delivery of BDNF at the peripheral nerve bridge site results in enhanced connectivity of the peripheral motor bridge in a rodent model of SCI.

Arteriovenous malformation-associated aneurysms in the pediatric population.

OBJECT: Conventional cerebral angiography and treatment for ruptured arteriovenous malformations (AVMs) in children are often performed in a delayed fashion. In adults, current literature suggests that AVM-associated aneurysms may be more likely to hemorrhage than isolated AVMs, which often leads to earlier angiography and endovascular treatment of associated aneurysms. The nature of AVM-associated aneurysms in the pediatric population is virtually unknown. In this report, the authors investigate the relationship of associated aneurysms in a large group of children with AVMs. METHODS: Seventy-seven pediatric patients (≤ 21 years old) with AVMs were treated at the Columbia University Medical Center between 1991 and 2010. Medical records and imaging studies were retrospectively reviewed, and associated aneurysms were classified as arterial, intranidal, or venous in location. Clinical presentation and outcome variables were compared between children with and without AVM-associated aneurysms. RESULTS: A total of 30 AVM-associated aneurysms were found in 22 children (29% incidence). Eleven were arterial, 9 intranidal, and 10 were venous in location. There was no significant difference in the rate of hemorrhage (p = 0.91) between children with isolated AVMs (35 of 55 [64%]) and children with AVM-associated aneurysms (13 of 22 [59%]). However, of the 11 children with AVM-associated aneurysms in an arterial location, 10 presented with hemorrhage (91%). An association with hemorrhage was significant in univariate analysis (p = 0.045) but not in multivariate analysis (p = 0.37). CONCLUSIONS: Associated aneurysms are present in nearly a third of children with AVMs, and when arterially located, are more likely to present with hemorrhage. These data suggest that early angiography with endovascular treatment of arterial-based aneurysms in children with AVMs may be indicated.

Spinal cord bypass surgery with intercostal and spinal accessory nerves: an anatomical feasibility study in human cadavers.

OBJECT: Despite extensive study, no meaningful progress has been made in encouraging healing and recovery across the site of spinal cord injury (SCI) in humans. Spinal cord bypass surgery is an unconventional strategy in which intact peripheral nerves rostral to the level of injury are transferred into the spinal cord below the injury. This report details the feasibility of using spinal accessory nerves to bypass cervical SCI and intercostal nerves to bypass thoracolumbar SCI in human cadavers. METHODS: Twenty-three human cadavers underwent cervical and/or lumbar laminectomy and dural opening to expose the cervical cord and/or conus medullaris. Spinal accessory nerves were harvested from the Erb point to the origin of the nerve's first major branch into the trapezius. Intercostal nerves from the T6-12 levels were dissected from the lateral border of paraspinal muscles to the posterior axillary line. The distal ends of dissected nerves were then transferred medially and sequentially inserted 4 mm deep into the ipsilateral cervical cord (spinal accessory nerve) or conus medullaris (intercostals). The length of each transferred nerve was measured, and representative distal and proximal cross-sections were preserved for axonal counting. RESULTS: Spinal accessory nerves were consistently of sufficient length to be transferred to caudal cervical spinal cord levels (C4-8). Similarly, intercostal nerves (from T-7 to T-12) were of sufficient length to be transferred in a tension-free manner to the conus medullaris. Spinal accessory data revealed an average harvested nerve length of 15.85 cm with the average length needed to reach C4-8 of 4.7, 5.9, 6.5, 7.1, and 7.8 cm. The average length of available intercostal nerve from each thoracic level compared with the average length required to reach the conus medullaris in a tension-free manner was determined to be as follows (available, required in cm): T-7 (18.0, 14.5), T-8 (18.7, 11.7), T-9 (18.8, 9.0), T-10 (19.6, 7.0), T-11 (18.8, 4.6), and T-12 (15.8, 1.5). The number of myelinated axons present on cross-sectional analysis predictably decreased along both spinal accessory and intercostal nerves as they coursed distally. CONCLUSIONS: Both spinal accessory and intercostal nerves, accessible from a posterior approach in the prone position, can be successfully harvested and transferred to their respective targets in the cervical spinal cord and conus medullaris. As expected, the number of axons available to grow into the spinal cord diminishes distally along each nerve. To maximize axon "bandwidth" in nerve bypass procedures, the most proximal section of the nerve that can be transferred in a tension-free manner to a spinal level caudal to the level of injury should be implanted. This study supports the feasibility of SAN and intercostal nerve transfer as a means of treating SCI and may assist in the preoperative selection of candidates for future human clinical trials of cervical and thoracolumbar SCI bypass surgery.

Efficacy of facial nerve-sparing approach in patients with vestibular schwannomas.

OBJECT: The goal of this article was to show that a combination of facial nerve-sparing microsurgical resection and Gamma Knife surgery (GKS) for expansion of any residual tumor can preserve good facial nerve function in patients with recurrent vestibular schwannoma (VS). METHODS: Records of individuals treated by a single surgeon with a facial nerve-sparing technique for a VS between 1998 and 2009 were retrospectively analyzed for tumor recurrence. Of the 383 patients treated for VS, 151 underwent microsurgical resection, and 20 (13.2%) of these patients required postoperative retreatment for a significant expansion of residual tumor after microsurgery. These 20 patients were re-treated with GKS. RESULTS: The rate of preservation of good facial nerve function (Grade I or II on the House-Brackmann scale) in patients treated with microsurgery for VS was 97%. Both subtotal and gross-total resection had excellent facial nerve preservation rates (97% vs 96%), although subtotal resection carried a higher risk that patients would require retreatment. In patients re-treated with GKS after microsurgery, the rate of facial nerve preservation was 95%. CONCLUSIONS: In patients with tumors that cannot be managed with radiosurgery alone, a facial nerve-sparing resection followed by GKS for any significant regrowth provides excellent facial nerve preservation rates.

Isoflurane preconditioning affords functional neuroprotection in a murine model of intracerebral hemorrhage.

INTRODUCTION: Exposure to isoflurane gas prior to neurological injury, known as anesthetic preconditioning, has been shown to provide neuroprotective benefits in animal models of ischemic stroke. Given the common mediators of cellular injury in ischemic and hemorrhagic stroke, we hypothesize that isoflurane preconditioning will provide neurological protection in intracerebral hemorrhage (ICH). METHODS: 24 h prior to intracerebral hemorrhage, C57BL/6J mice were preconditioned with a 4-h exposure to 1% isoflurane gas or room air. Intracerebral hemorrhage was performed using a double infusion of 30-µL autologous whole blood. Neurological function was evaluated at 24, 48 and 72 h using the 28-point test. Mice were sacrificed at 72 h, and brain edema was measured. RESULTS: Mice preconditioned with isoflurane performed better than control mice on 28-point testing at 24 h, but not at 48 or 72 h. There was no significant difference in ipsilateral hemispheric edema between mice preconditioned with isoflurane and control mice. CONCLUSION: These results demonstrate the early functional neuroprotective effects of anesthetic preconditioning in ICH and suggest that methods of preconditioning that afford protection in ischemia may also provide protection in ICH.

Alterations in systemic complement component 3a and 5a levels in patients with cerebral arteriovenous malformations.

The role of the complement cascade in the pathophysiology of cerebral arteriovenous malformation (AVM) is largely undefined. Complement subcomponents, C3a and C5a, are potent anaphylatoxins and key mediators of immuno-inflammatory response. Complement activation may contribute to the pro-inflammatory state observed in AVM. Thus, we sought to determine the systemic levels of C3a and C5a and their response to treatments in patients with AVM. Blood samples of 18 patients undergoing treatment for unruptured AVM, and from 30 healthy control participants, were obtained at four times: (i) pre-treatment, (ii) 24-hours post-embolization, (iii) 24-hours post-resection, and at 1-month follow-up. Plasma concentrations of C3a and C5a were measured using enzyme-linked immunosorbent assay. The pre-treatment mean plasma C3a level was significantly higher in patients with AVM (1817±168 ng/mL) compared to controls (1126±151 ng/mL). The mean C3a level decreased 24-hours after embolization (1482±170 ng/mL) and remained at statistically similar levels 24-hours after resection (1511±149 ng/mL) and at 1-month follow-up (1535±133 ng/mL). Mean C3a levels at the three time points were higher than control levels.The baseline mean plasma C5a level was significantly elevated in patients with AVM (13.1±2.2 ng/mL) compared to controls (3.9±1.5 ng/mL).Mean C5a level decreasedpost-embolization (8.2±2.3 ng/mL) and remained at similar levels post-resection (8.5±3.0 ng/mL) and at 1-month follow-up (7.7±2.9 ng/mL). Mean C5a levels at the three time points were significantly higher than the control levels. We conclude that systemic C3a and C5a levels in patients with AVM are elevated at baseline, decrease significantly after embolization, and remain at the new baseline levels after surgery and 1-month follow-up.

Complex basilar artery aneurysms treated using surgical basilar occlusion: a modern case series. Clinical article.

OBJECT: Complex aneurysms of the basilar artery (BA) apex can be successfully treated using surgical occlusion of the proximal BA. Since the introduction of the Guglielmi detachable coil in 1991, the focus on treating BA aneurysms has been on using endovascular techniques. Outcomes with endovascular techniques have been less than optimal for large and complex aneurysms. The authors therefore report on their current 22-year experience with surgical BA occlusion for complex BA aneurysms and long-term outcome. METHODS: Fifteen patients underwent surgical BA occlusion at Columbia University Medical Center for complex basilar apex aneurysms between 1987 and 2009. The clinical records of each patient were reviewed for details of presentation, hospital course, operative intervention, and outcome. RESULTS: Postoperatively, all patient encounters were recorded at discharge, at the 1-month and 1-year follow-up evaluations, and at long-term outcome. Twelve (80%) of 15 patients experienced no new postoperative neurological deficits. Three patients presenting with severe neurological impairment (modified Rankin Scale [mRS] score > 3) made excellent recoveries (mRS Scores 1-2) at long-term follow-up. One patient died, 1 suffered a stroke during the postoperative angiogram which resulted in hemiparesis, and 1 suffered internuclear ophthalmoplegia which resolved by the 1-month follow-up. Long-term follow-up occurred at an average of 3 ± 4.5 years, ranging from 2 months (for a recently treated patient) to 18 years. The average mRS score at long-term follow-up was 1 ± 1.5. No patient experienced postoperative hemorrhage, rebleeding, or delayed neurological deterioration. CONCLUSIONS: Surgical occlusion of the BA is an effective treatment option offering a high rate of angiographic cure in a single procedure for patients with complex BA aneurysms. The ability to surgically perform point occlusion of the BA without impairment of brainstem perforators, while maintaining collateral blood flow to the posterior circulation branch vessels, may provide an advantage compared with endovascular treatments.

Surgical management of ventral intradural spinal lesions.

OBJECTIVE: Access to the ventral intradural spinal canal may be required for treatment of a variety of lesions affecting the spinal cord and adjacent intradural structures. Adequate exposure is usually achieved through a standard posterior laminectomy or posterolateral approaches, although formal anterior approaches are used to access lesions in the subaxial cervical spine. Modifications of the standard posterior exposure as well as ventral or ventrolateral approaches are increasingly being used for treating intradural spinal pathologies. In this study, the authors review their experience with 35 consecutive cases of ventral intradural spinal lesions. METHODS: Only patients with intradural lesions located completely ventral to the dentate ligament attachments were included in this retrospective study. Patients with the following lesions were excluded from the study: lesions at the level of the filum terminale/cauda equina, lesions with any component that extended dorsally to the dentate ligament, or lesions with extradural extension (that is, dumbbell tumors) below the C-2 level. Between January 2000 and September 2009, a total of 35 patients (age range 17-72 years, mean 42.6 years) with ventral intradural spinal pathology underwent surgery at the authors' institution. RESULTS: There were 28 intradural extramedullary mass lesions: 15 meningiomas, 12 solitary schwannomas, and 1 neuroenteric cyst. Surgical approaches to these lesions included 23 posterior or posterolateral approaches, 4 anterior approaches with corpectomy followed by tumor resection and reconstruction, and 1 lateral transforaminal resection. No patient had evidence of instability at follow-up, which ranged from 6 months to 8 years in duration. One patient had worsened spinal cord function following surgery. There were 7 patients with intramedullary lesions: 2 hemangioblastomas, 2 cavernous malformations, 2 perimedullary fistulas, and 1 astrocytoma. All but 1 were superficial pia-based lesions arising ventral to the dentate ligament. Five of the 6 pia-based lesions were successfully resected via a standard posterior laminectomy, partial facetectomy with dentate section, and spinal cord rotation. One midline pial lesion was successfully removed with a minimally invasive retropleural thoracotomy. The astrocytoma was resected through an anterior cervical corpectomy, which was followed by instrumented reconstruction. There were no significant complications or neurological morbidity at follow-up (range 9 months-6 years). CONCLUSIONS: Most intradural spinal lesions can be treated with contemporary microsurgical techniques with long-term control or cure of the lesion and preservation of neurological function. Standard posterior approaches provide adequate exposure to safely remove the vast majority of these lesions without the need for a potentially destabilizing resection of the facet or pedicle. Posterior exposures with varying degrees of lateral bone resection, dentate ligament division, and gentle cord rotation may also provide adequate exposure for safe removal of nonmidline ventrolateral superficial pial presenting spinal cord lesions. Nevertheless, in certain cases of ventral intradural lesions, anterior approaches are necessary and should be considered under appropriate circumstances.

Advances in neuroprotective strategies: potential therapies for intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is associated with higher mortality and morbidity than any other form of stroke. However, there currently are no treatments proven to improve outcomes after ICH, and therefore, new effective therapies are urgently needed. Growing insight into ICH pathophysiology has led to the development of neuroprotective strategies that aim to improve the outcome through reduction of secondary pathologic processes. Many neuroprotectants target molecules or pathways involved in hematoma degradation, inflammation or apoptosis, and have demonstrated potential clinical benefits in experimental settings. We extensively reviewed the current understanding of ICH pathophysiology as well as promising experimental neuroprotective agents with particular focus on their mechanisms of action. Continued advances in ICH knowledge, increased understanding of neuroprotective mechanisms, and improvement in the ability to modulate molecular and pathologic events with multitargeting agents will lead to successful clinical trials and bench-to-bedside translation of neuroprotective strategies.

Polymorphisms in complement component 3 (C3F) and complement factor H (Y402H) increase the risk of postoperative neurocognitive dysfunction following carotid endarterectomy.

BACKGROUND: Up to 28% of patients undergoing carotid endarterectomy (CEA) are estimated to experience neurocognitive dysfunction following surgery. The complement cascade plays a central role in ischaemia-reperfusion injury. The authors investigated the effect of common polymorphisms in the complement component 3 (C3F) and complement factor H (CFH Y402H) genes on incidence of neurocognitive dysfunction post-CEA. METHODS: This study examined a nested cohort of prospectively recruited patients receiving elective CEA, who were genotyped for the C3F or Y402H polymorphisms. Each patient underwent a standard battery of eight neuropsychometric tests before, and 1 day and 30 days after, surgery. RESULTS: 57 of 142 (40%) CEA patients had at least one copy of the C3F allele (C3F+), and 17 of 137 (12%) patients had two copies of the CFH Y402H allele (Y402H++). At postoperative day 1, patients were three times (OR 3.05, p=0.045) or six times (OR 6.41, p=0.006) more likely to experience moderate-to-severe neurocognitive dysfunction if they carried the C3F+ or Y402H++ genotype, respectively. Patients with both risk genotypes had an almost eightfold risk of dysfunction (OR 7.67, p=0.046). Right-hand-dominant C3F+ subjects undergoing right-side CEA performed significantly worse on tests of visuospatial function than C3F- subjects. At day 30, C3F+ and Y402H++ genotypes trended towards significance as predictors of dysfunction (p=0.07 and p=0.22, respectively). CONCLUSION: The C3F and Y402H polymorphisms are strong independent predictors of moderate-to-severe neurocognitive dysfunction at 1 day following CEA. Furthermore, patients undergoing right-sided CEA are predisposed to deficits associated with cortex ipsilateral to the operative carotid artery.

Mechanical treatment of vasospasm.

OBJECTIVE: Since cerebral vasospasm (CV) was first described nearly half a century ago, significant progress has been made in understanding its underlying pathophysiology and developing treatment modalities. The purpose of this review is to discuss the rationale behind mechanical interventions for CV as well as the efficacy and complications associated with these treatment options. METHODS: The authors summarize the pertinent literature on the mechanical treatment of CV, focusing first on balloon angioplasty, second on therapy combined with intra-arterial drug infusion, and concluding by briefly discussing intra-aortic balloon counterpulsation. The epidemiology, pathophysiology, technique, outcome, timing and complications are discussed for each treatment option. RESULTS: A review of the relevant medical literature reveals that in the last 20 years, endovascular techniques including transluminal balloon angioplasty, intra-arterial drug infusion and newer experimental strategies have provided an important supplement to the established medical therapy. DISCUSSION: Despite these developments, however, CV remains a major contributor to poor outcome following aSAH and continued efforts are necessary to improve and refine endovascular strategies as well as develop new treatment modalities.