Neurosurgery Blog

J Neurosurg Spine 15:295–310, 2011.DOI: 10.3171/2011.4.SPINE10330

The authors compared the effectiveness of instrumented posterior lumbar interbody fusion (iPLIF) and instrumented posterolateral fusion (iPLF) for the treatment of low-back pain (LBP) due to degenerative lumbar disease.

Methods. Relevant randomized controlled trials (RCTs) and comparative observational studies through December 2009 were identified using a retrieval strategy of sensitive and specific searches. The study design, participant characteristics, interventions, follow-up rate and period, and outcomes were abstracted after the assessment of methodological quality of the trials. Analyses were performed following the method guidelines of the Cochrane Back Review Group.
Results. Nine studies were identified—3 RCTs and 6 comparative observational studies. No significant difference was found between the 2 fusion procedures in the global assessment of clinical outcome (OR 1.51, 95% CI 0.71–3.22, p = 0.29) and complication rate (OR 0.55, 95% CI 0.16–1.86, p = 0.34). Both techniques were effective in reducing pain and improving functional disability, as well as restoring intervertebral disc height. Instrumented PLIF was more effective in achieving solid fusion (OR 2.60, 95% CI 1.35–5.00, p = 0.004), a lower reoperation rate (OR 0.20, 95% CI 0.03–1.29, p = 0.09), and better restoration of segmental angle and lumbar lordotic angle than iPLF. There were no significant differences between the fusion methods regarding blood loss (weighted mean difference –179.63, 95% CI –516.42 to 157.15, p = 0.30), and operating time (weighted mean difference 8.03, 95% CI –45.46 to 61.53, p = 0.77).

Conclusions. The authors’ analysis provided moderate-quality evidence that iPLIF has the advantages of higher fusion rate and better restoration of spinal alignment over iPLF. No significant differences were identified between iPLIF and iPLF concerning clinical outcome, complication rate, operating time, and blood loss.

Neurosurgery 69[ONS Suppl 1]:ons49–ons63, 2011 DOI: 10.1227/NEU.0b013e3182155a52

Effective hemostasis is mandatory for brain tumor surgery. Microporous polysaccharide hemosphere (MPH) powder, a white powder compounded from potato starch, was recently introduced for surgical and emergency application.

OBJECTIVE: To evaluate the safety and efficacy of MPHs in brain tumor surgery.

METHODS: Thirty-three patients (mean age, 58 years; range, 22-84 years) underwent microsurgical brain tumor resection. Final hemostasis was performed by topical application of MPHs, video recorded, and subsequently analyzed. Blood samples were taken before surgery, before application of hemospheres, and postoperatively. Volume measurements of the tumor, resection cavity, and postoperative hematoma were done on magnetic resonance imaging and computed tomography scans. Clinical examinations focused on neurological outcome, complications, and allergic reactions.

RESULTS: Effective hemostasis was achieved by exclusive use of MPHs in 32 patients. In 1 patient, a single arterial bleeding underwent additional bipolar electrocauterization. Mean operative time was 156.8 minutes (range, 60-235 minutes). Hemostasis with MPHs required 57 seconds (mean; range, 8-202 seconds). Subjective neurosurgeons’ ranking of the hemostasis effect indicated excellent satisfaction. For the first 3 months, there was no hemospheres-related postoperative neurological worsening, no signs of allergic reaction, and no embolic complications. Early postoperative and 3-month follow-up magnetic resonance imaging and computed tomography scans excluded any expansive bleeding complication. As early as postoperative day 1, MPHs were no longer detected. There was no tumor mimicking contrast enhancement.

CONCLUSION: In neurosurgery, MPHs allow fast and effective minimally invasive hemostasis. In this small case series, no adverse reactions were found.

J Neurosurg 115:647–658, 2011.DOI: 10.3171/2010.11.JNS102148

The aim of this paper was to measure the posterior fossa (PF) volume increase resulting from a givensized occipital craniectomy in Chiari malformation Type I surgery and to analyze its correlations with the PF size and the treatment response, with the perspective of tailoring the amount of bone removal to the patient-specific PF dimensions.

Methods. Between January 2005 and June 2006, 11 adult patients with symptomatic Chiari malformation Type I underwent a standardized PF decompression. A prospective evaluation with clinical examination, functional grading, and MR imaging measurement protocols was performed pre- and postoperatively. A method is reported for the measurement of PF volume (PFV) after surgery. The degree of PFV increase was compared with the preoperative size of the PF and with the clinical outcome.

Results. All 11 patients improved postoperatively, with complete and partial recovery in 4 and 7 patients, respectively. No postoperative complication occurred after a mean follow-up period of 45 months. The mean relative increase in PFV accounted for 10% (range 1.5%–19.7%) of the initial PFV; the increase was greater in cases in which the PF was small (r = -0.52, p = 0.09) and the basiocciput was short (r = -0.37, p = 0.2). A statistically significant positive correlation was found between the degree of PFV increase and the treatment response (p = 0.014); complete recovery was observed with a PFV increase of 15% and partial recovery with an increase of 7%.

Conclusions. The treatment response is significantly influenced by the degree of PFV increase, which is dependent on the size of the PF and the extent of the craniectomy, suggesting that the optimal patient-specific PFV increase could be predicted on the basis of preoperative MR imaging and enhancing the perspective that the craniectomy size could be tailored to the individual PFV.

J Neurosurg 115:592–601, 2011. DOI: 10.3171/2011.5.JNS10505

Catheter-based evacuation is a novel surgical approach for the treatment of brain hemorrhage. The object of this study was to evaluate the safety and efficacy of ultrasound in combination with recombinant tissue plasminogen activator (rt-PA) delivered through a microcatheter directly into spontaneous intraventricular (IVH) or intracerebral (ICH) hemorrhage in humans.

Methods. Thirty-three patients presenting to the Swedish Medical Center in Seattle, Washington, with ICH and IVH were screened between November 21, 2008, and July 13, 2009, for entry into this study. Entry criteria included the spontaneous onset of intracranial hemorrhage ≥ 25 ml and/or IVH producing ventricular obstruction. Nine patients (6 males and 3 females, with an average age of 63 years [range 38–83 years]) who met the entry criteria consented to participate and were entered into the trial. A ventricular drainage catheter and an ultrasound microcatheter were stereotactically delivered together, directly into the IVH or ICH. Recombinant tissue plasminogen activator and 24 hours of continuous ultrasound were delivered to the clot. Gravity drainage was performed. In patients with IVHs, 3 mg of rt-PA was injected; in patients with intraparenchymal hemorrhages, 0.9 mg of rt-PA was injected. The rt-PA was delivered in 3 doses over 24 hours.

Results. All patients had significant volume reductions in the treated hemorrhage. The mean percentage volume reduction after 24 hours of therapy, as determined on CT and compared with pretreatment stability scans, was 59 ± 5% (mean ± SEM) for ICH and 45.1 ± 13% for IVH (1 patient with ICH was excluded from analysis because of catheter breakage). There were no intracranial infections and no significant episodes of rebleeding according to clinical or CT assessment. One death occurred by 30 days after admission. Clinical improvements as determined by a decrease in the National Institutes of Health Stroke Scale score were demonstrated at 30 days after treatment in 7 of 9 patients. The rate of hemorrhage lysis was compared between 8 patients who completed treatment, and patient cohorts treated for IVH and ICH using identical doses of rt-PA and catheter drainage but without the ultrasound (courtesy of the MISTIE [Minimally Invasive Surgery plus T-PA for Intracerebral Hemorrhage Evacuation] and CLEAR II [Clot Lysis Evaluating Accelerated Resolution of Intraventricular Hemorrhage II] studies). Compared with the MISTIE and CLEAR data, the authors observed a faster rate of lysis during treatment for IVH and ICH in the patients treated with sonolysis plus rt-PA versus rt-PA alone.

Conclusions. Lysis and drainage of spontaneous ICH and IVH with a reduction in mass effect can be accomplished rapidly and safely through sonothrombolysis using stereotactically delivered drainage and ultrasound catheters via a bur hole. A larger clinical trial with catheters specifically designed for brain blood clot removal is warranted.

Neurosurgery 69:581–589, 2011 DOI: 10.1227/NEU.0b013e3182181b89

Transcranial magnetic stimulation (TMS) is the only noninvasive method for presurgical stimulation mapping of cortical function. Recent technical advancements have significantly increased the focality and usability of the method.

OBJECTIVE: To compare the accuracy of a 3-dimensional magnetic resonance imaging– navigated TMS system (nTMS) with the gold standard of direct cortical stimulation (DCS).

METHODS: The primary motor areas of 20 patients with rolandic tumors were mapped preoperatively with nTMS at 110% of the individual resting motor threshold. Intraoperative DCS was available from 17 patients. The stimulus locations eliciting the largest electromyographic response in the target muscles (‘‘hotspots’’) were determined for both methods.

RESULTS: The nTMS and DCS hotspots were located on the same gyrus in all cases. The mean 6 SEM distance between the nTMS and DCS hotspots was 7.83 6 1.18 mm for the abductor pollicis brevis (APB) muscle (n = 15) and 7.07 6 0.88 mm for the tibialis anterior muscle (n = 8). When a low number of DCS stimulations was performed, the distance between the nTMS and DCS hotspots increased substantially (r = 20.86 for APB). After the exclusion of the cases with , 15 DCS APB responses, the mean 6 SEM distance between the hotspots was only 4.70 6 1.09 mm for APB (n = 8).

CONCLUSION: Peritumoral mapping of the motor cortex by nTMS agreed well with the gold standard of DCS. Thus, nTMS is a reliable tool for preoperative mapping of motor function.

Neurosurg Rev. DOI 10.1007/s10143-011-0340-7

The paper describes a retrospective study of a consecutive series of 20 midline anterior cranial fossa meningiomas (five of the olfactory groove, 14 of the tuberculum sellae, and one clinoidal), which were operated on via a supraorbital keyhole approach between 2002 and 2008.

The series includes three males and 17 females (mean age 57 years, mean size of the tumors 3.5×3 cm, and mean follow-up 48 months). Gross total excision was achieved in 18 cases and subtotal resection in two. Out of 14 patients with visual deficits, nine patients improved, one remained stable, and three deteriorated. Two patients presented a recurrence 3 years after surgery. One peri-operative death was recorded.

The subgroup of patients with tuberculum sellae meningiomas was analyzed in details. A meta-analysis of the major series of such meningiomas in the last 20 years has been performed in order to compare results of different surgical techniques. With regard to primary outcomes of these tumors, gross total removal, restoration of visual function, morbidity, mortality, and recurrence rates, the supraorbital approach, for selected cases, seems to offer valuable results, comparable with those reported in conventional and endoscopic approaches and with very low surgical aggressiveness. However, statistical data available from the literature, particularly on visual function, are still too limited to draw definitive conclusions.

The best surgical option for the individual patient cannot yet be standardized and should be chosen on the basis of tumor anatomy, pre-operative clinical symptoms, and surgeon’s experience.

Acta Neurochir (2011) 153:1753–1759. DOI 10.1007/s00701-011-1065-7

Brainstem surgery bears a risk of damage to the corticospinal tract (CST). Motor-evoked potentials (MEPs) are used intraoperatively to monitor CST function in order to detect CST damage at a reversible stage and thus impede permanent neurological deficits. While the method of MEP is generally accepted, warning criteria in the context of brainstem surgery still have to be agreed on.

Method We analyzed 104 consecutive patients who underwent microsurgical resection of lesions affecting the brainstem. Motor grade was documented prior to surgery, early postoperatively and at discharge. A baseline MEP stimulation intensity threshold was defined and intraoperative testing aimed to keep MEP response amplitude constant. MEPs were considered deteriorated and the surgical team was notified whenever the threshold was elevated by ≥20 mA or MEP response fell under 50%.

Findings On the first postoperative day, 18 patients experienced new paresis that resolved by discharge in 11. MEPs deteriorated in 39 patients, and 16 of these showed new postoperative paresis, indicating a 41% risk of new paresis. In the remaining 2/18 patients, intraoperative MEPs were stable, although new paresis appeared postoperatively. In one of these patients, intraoperative hemorrhage caused postoperative swelling, and the new motor deficit persisted until discharge. Of all 104 patients, 7 deteriorated in motor grade at discharge, 92 remained unchanged, and 5 patients have improved.

Conclusions Adjustment of surgical strategy contributed to good motor outcome in 33/39 patients. MEP monitoring may help significantly to prevent motor deficits during demanding neurosurgical procedures on the brainstem.

J Neurosurg Spine 15:151–158, 2011. DOI: 10.3171/2011.3.SPINE0969

The goal of this study was to assess whether a stable but nonrigid nonfusion implant can stabilize the spine in degenerative diseases and also prevent instability following decompression. Instrumented spondylodesis is a recognized surgical treatment in degenerative disease of the lumbar spine. However, pain can develop at the bone graft donor site and the operative trauma can be very stressful in elderly patients, and it is suspected that there may be increased degenerative changes in the adjacent segments. In 2002, a nonrigid but rotationally stable pedicle screw and rod system was introduced, which could be used without additional fusion (referred to hereafter as the Cosmic system).

Methods. A total of 139 patients with degenerative disease of the lumbar spine underwent spinal stabilization with the Cosmic system without additional spondylodesis. Seventy patients had an additional decompression. The minimum follow-up was 2 years. The perioperative course, the clinical results, and the erect anteroposterior and lateral radiographs were recorded and compared with the preoperative data. The data were obtained from 6 different spine centers in Europe and documented on an Internet platform.

Results. The Oswestry Disability Index score improved from 48.9% to 22.5%, and the visual analog scale score decreased from 7.3 to 2.5. Lumbar lordosis did not change, nor did the adjacent disc height. Eleven patients underwent revision, 4 of them for implant failure. Of the 139 patients, 110 assessed the result as excellent, very good, or good; 24 as fair; and 5 as poor. A total of 122 patients would undergo surgery again. There were no significant differences between patients with or without an additional decompression.

Conclusions. The Cosmic system is a stable but nonrigid posterior nonfusion system. Implant complications are low and the clinical outcome is good. Longer follow-up is necessary to confirm the 2-year results.

J Neurosurg 115:232–239, 2011. DOI: 10.3171/2011.3.JNS101333

It has been demonstrated that an extensive resection (total or subtotal) may significantly increase the overall survival in patients with WHO Grade II gliomas (low-grade gliomas [LGGs]). Yet, recent data have shown that conventional MR imaging underestimates the spatial extent of LGG, since tumor cells were found up to 20 mm around MR imaging abnormalities. Thus, it was hypothesized that an extended resection with a margin beyond MR imaging–defined abnormalities—a “supratotal” resection—might improve the outcome of LGG. However, because of the frequent location of LGG within “eloquent” brain areas, it is often difficult to achieve such a supratotal resection. This could nevertheless be possible when LGGs involve “noneloquent” areas, even in the left dominant hemisphere.

The authors report on their use of awake electrical mapping to tailor the resection according to functional boundaries, that is, to pursue the resection beyond MR imaging–defined abnormalities, until corticosubcortical eloquent structures are encountered. Their aim was to apply this reliable surgical technique to LGGs located not within eloquent areas but distant from eloquent areas, to take a margin around the LGG visible on MR imaging while preserving brain function.

Methods. Fifteen right-handed patients with a total of 17 tumors underwent resection of WHO Grade II gliomas involving nonfunctional areas within the left dominant hemisphere. In all patients, seizures were the initial manifestation of the tumors. Awake surgery with intraoperative electrostimulation was performed in all cases. The resection was continued until the surgeon reached cortical and subcortical areas crucial for brain function, especially language, as defined by the intrasurgical electrical mapping. The extent of resection was evaluated on postoperative FLAIRweighted MR images.

Results. Despite transient neurological worsening in 60% of cases, all patients recovered and returned to a normal life. Seizure control was obtained in all patients with a decrease of antiepileptic drug therapy. Postoperative MR imaging showed that total resection was achieved in all 17 tumors and supratotal resection in 15. The average volume of the postoperative cavity (36.8 cm3) was significantly larger than the mean preoperative tumor volume (26.6 cm3) (p = 0.009). Neuropathological examination confirmed the diagnosis of WHO Grade II glioma in all cases. The mean duration of postoperative follow-up was 35.7 months (range 6–135 months). Only 4 of 15 patients experienced recurrence (without anaplastic transformation); the average time to recurrence in these cases was 38 months; radiotherapy was performed 6 years after the relapse in 1 case; no other patients received any adjuvant treatment. This series was compared with a control group of 29 patients who had “only” complete resection: anaplastic transformation was observed in 7 cases in the control group but not in any case in the series of patients who underwent supracomplete resection (p = 0.037). Furthermore, adjuvant treatment was administered in 10 patients in the control group compared with 1 patient who underwent supracomplete resection (p = 0.043).

Conclusions. These findings support the usefulness of awake surgery with intraoperative functional (language) mapping with the attempt to perform supratotal resection of LGGs involving noneloquent areas in the left hemisphere. Indeed, the extent of resection was significantly increased in all cases but 2, with no additional permanent deficit and with control of seizures in all patients. The goal of supracomplete resection is currently to delay the anaplastic transformation, even if it does not (yet) enable a cure.

J Neurosurg 115:151–158, 2011. DOI: 10.3171/2011.1.JNS101492

Traditional ventriculoperitoneal (VP) shunt surgery involves insertion of the distal catheter by minilaparotomy. However, minilaparotomy may be a significant source of morbidity during shunt surgery. Laparoscopic insertion of the distal catheter is an alternative technique that may simplify and improve the safety of shunt surgery.

Methods. The authors performed a retrospective review of hospital records of all patients undergoing new VP shunt insertion at a tertiary care center between 2004 and 2009. Patient characteristics and outcomes were compared between patients undergoing open or laparoscopic insertion of the distal catheter. Independent variables in the analysis included age, sex, race, body mass index, surgical technique, previous VP shunt placement, previous abdominal procedures, American Society of Anesthesiology (ASA) score, and indication for shunt placement. Dependent variables included the occurrence of shunt failure, cause of shunt failure, complications, length of stay (LOS), LOS after shunt placement, estimated blood loss, and operative time.

Results. The authors identified 810 patients who met the inclusion criteria; open or laparoscopic distal catheter insertion was performed in 335 and 475 patients, respectively. There were no significant differences between the groups regarding age, race, ASA score, or indication for shunt placement. The most common indication was hydrocephalus due to subarachnoid hemorrhage, followed by tumor-associated hydrocephalus, normal pressure hydrocephalus (NPH), and hydrocephalus due to trauma. The incidence of shunt failure was not statistically different between cohorts, occurring in 20.0% of laparoscopic and 20.9% of open catheter placement cases (p = 0.791). With analysis of causes of shunt failure, shunt obstruction occurred significantly more often in the open surgery cohort (p = 0.012). In patients with a known cause shunt obstruction, distal obstruction occurred in 35.7% of the open cohort obstructions and 4.8% of the laparoscopic cohort obstructions (p = 0.014). The relative risk of distal obstruction in open cases compared with laparoscopic cases was 7.50. Infections occurred in 8.2% of laparoscopic cases compared with 6.6% of open cases (p = 0.419). Within the NPH subgroup, the laparoscopically treated patients had significantly more overdrainage (p = 0.040), whereas those in the open cohort experienced significantly more shunt obstructions (p = 0.034). Laparoscopically treated patients had shorter operative times (p < 0.0005), inpatient LOS (p < 0.001), and inpatient LOS after VP shunt placement (p = 0.01) as well as less blood loss (p = 0.058).

Conclusions. To our knowledge this is the largest reported comparison of distal VP shunt catheter insertion techniques. Compared with minilaparotomy, the laparoscopic approach was associated with decreased time in the operating room and a decreased LOS. Moreover, laparoscopy was associated with fewer distal shunt obstructions. Laparoscopic shunt surgery is a viable alternative to traditional shunt surgery.

J Neurosurg 115:49–54, 2011. DOI: 10.3171/2011.2.JNS101759

The retrosigmoid intradural suprameatal approach with the patient in a semisitting position is an effective alternative to transpetrosal approaches for the treatment of petroclival meningiomas. The authors have made a simple modification to the retrosigmoid intradural suprameatal approach by using the lateral oblique position and preferentially dividing the tentorium with limited drilling of the suprameatal bone, which is termed the “lateral su- pracerebellar transtentorial approach.”

Methods. Twenty-six patients with petroclival meningiomas surgically treated via the lateral supracerebellar transtentorial approach were analyzed. All tumors had most of their bulk in the posterior fossa with some degree of extension into the middle fossa and/or Meckel cave. The patient is placed in the lateral oblique position, and a standard retrosigmoid craniotomy is performed. The tentorium medial to the trigeminal nerve is incised toward the free edge, which improves exposure to the petroclival region without extensive resection of the suprameatal petrous bone.

Results. Gross-total resection was achieved in 11 patients (42%). Ten patients (38%) underwent subtotal resection, and 5 patients (19%) underwent partial resection. There was no incidence of operative death, and the postoperative permanent morbidity rate was 15%. All patients except one did well postoperatively and were independent at the time of their last follow-up examinations.

Conclusions. The lateral supracerebellar transtentorial approach provides the simplest and safest access to the petroclival region. It offers an advantageous approach to petroclival meningiomas exclusively located in the posterior fossa with minimal extension into the Meckel cave and middle fossa.

Neurosurgery 68[ONS Suppl 2]:ons300–ons309, 2011 DOI: 10.1227/NEU.0b013e3182124810

Neurovascular surgeons have been trying to find a solution to the problem of surgical invasiveness by applying minimally invasive keyhole approaches.

OBJECTIVE: To evaluate the feasibility and surgical outcomes of a superciliary keyhole approach for unruptured intracranial aneurysms (UIAs) as an alternative to a pterional approach.

METHODS: The authors report on a consecutive series of patients who underwent a superciliary approach for clipping UIAs smaller than 15 mm arising at the supraclinoid internal carotid artery (ICA), A1 segment, anterior communicating artery (ACoA), and M1 segment including the middle cerebral artery (MCA) bifurcation. The data were compared with a historical control group (n = 90) who underwent a pterional approach for UIAs.

RESULTS: A total of 120 aneurysms were successfully clipped in 102 patients with a mean age of 58 years. There was no direct mortality related to the surgery, and only 1 (1.0%) patient developed significant morbidity adversely affecting the Glasgow Outcome Scale score. The superciliary approach demonstrated statistically significant advantages over the pterional approach, including a shorter operative duration (mean, 120 min), no intraoperative blood transfusion, and extremely rare postoperative epidural hemorrhages. In addition, temporalis atrophy was rare and palsy of the frontalis persisting more than 6 months only occurred in 6 patients (5.9%) and was resolved within 2 years. The overall cosmetic outcome was excellent.

CONCLUSION: A superciliary approach can be a reasonable alternative to a pterional approach for small (,15 mm) UIAs arising at the supraclinoid ICA, A1, ACoA, and M1 segment including the MCA bifurcation.

Neurosurgery 69:194–206, 2011 DOI: 10.1227/NEU.0b013e31821d0e4c

Awake craniotomy with electrocortical mapping and intraoperative magnetic resonance imaging (iMRI) are established techniques for maximizing tumor resection and preserving function, but there has been little experience combining these methodologies.

OBJECTIVE: To report our experience of combining awake craniotomy and iMRI with a 1.5-T movable iMRI for resection of gliomas in close proximity to eloquent cortex.

METHODS: Twelve patients (9 male and 3 female patients; age, 32-60 years; mean, 41 years) undergoing awake craniotomy and iMRI for glioma resections were identified from a prospective database. Assessments were made of how these 2 modalities were integrated and what impact this strategy had on safety, surgical decision making, workflow, operative time, extent of tumor resection, and outcome.

RESULTS: Twelve craniotomies were safely performed in an operating room equipped with a movable 1.5-T iMRI. The extent of resection was limited because of proximity to eloquent areas in 5 cases: language areas in 3 patients and motor areas in 2 patients. Additional tumor was identified and resected after iMRI in 6 patients. Average operating room time was 7.9 hours (range, 5.9-9.7 hours). Compared with preoperative neurological function, immediate postoperative function was stable/improved in 7 and worse in 5; after 30 days, it was stable/improved in 11 and worse in 1.

CONCLUSION: Awake craniotomy and iMRI with a movable high-field-strength device can be performed safely to maximize resection of tumors near eloquent language areas.

Acta Neurochir (2011) 153:1487–1495. DOI 10.1007/s00701-011-1046-x

Videoangiography using indocyanine green (ICG) has been used in the ophthalmologic field for a long time. It was introduced to the neurosurgical field several years ago but has been limited to vascular surgeries. We applied ICG videoangiography to brain tumor surgery and evaluated the usefulness.

Methods Twenty-three patients with a brain tumor who underwent microsurgical resection were analyzed. The pathological diagnosis was meningioma in 15 patients, metastasis in three, glioma in three, and hemangioblastoma in two. A microscope with a special filter and infrared excitation light to illuminate the operating field was used in this study. The intravascular fluorescence was imaged with a video camera attached to the microscope. ICG was injected intravenously with the dose of 5–25 mg, and overall, ICG was injected intraoperatively 32 times.

Results ICG videoangiography allowed for an excellent evaluation of blood flow in the tumoral and peri-tumoral vessels both before and after the resection in all cases.

Conclusions ICG videoangiography is a useful method for monitoring blood flow in the exposed vessels during microsurgery for a brain tumor. This noninvasive method is simple, safe, cost-effective, and easily repeatable. Before resection, it provides information on the tumoral and peritumoral circulation including sequential visualization of vessels or direction of the blood flow. After resection, it checks the patency of the peri-tumoral vessels and is especially useful for the vein. This ICG videoangiography can be an alternative tool to intraoperative angiography or Doppler ultrasonography in selective cases.

Acta Neurochir. DOI 10.1007/s00701-011-1068-4

Cervical lateral mass screw fixation is indicated for the treatment of cervical subaxial C3-C7 lesions associated with instability.

Method The authors first describe the surgical anatomy of the subaxial cervical posterior approach. Then the Magerl technique is detailed. In particular, tricks to avoid complications are presented. The ideal screw entry point, direction, size and exit point are mentioned. A surgical video, artist’s drawings and a radiological case report are included.

Conclusion The Magerl technique is a safe and effective lateral mass fixation technique. Respecting anatomical landmarks is crucial to avoid nerve root, vertebral artery and facet joint injury.

Neurosurg Rev. DOI 10.1007/s10143-011-0329-2

Esthesioneuroblastoma is an uncommon malignant tumor originating in the upper nasal cavity. The surgical treatment for this tumor has traditionally been via an open craniofacial resection. Over the past decade, there has been tremendous development in endoscopic techniques.

In this report, we performed a retrospective analysis of patients with esthesioneuroblastomas treated with a purely endonasal endoscopic approach and resection at the Johns Hopkins Hospital between January 2005 and April 2010.

A total of eight patients with esthesioneuroblastoma, five men and three women, were identified. Six patients were treated for primary disease, and two were treated for tumor recurrence. The modified Kadish staging was A in one patient (12.5%), B in two patients (25%), C in four patients (50%), and D in one patient (12.5%). All patients had a complete resection with negative intraoperative margins. One patient had intraoperative hypertension; there were no perioperative complications. With a mean follow-up of over 27 months, all patients are without evidence of disease. In addition, we reviewed the literature and identified several overlapping case series of patients with esthesioneuroblastoma treated via a purely endoscopic technique.

Our series adds to the growing experience of expanded endonasal endoscopic surgery in the treatment of skull base tumors including esthesioneuroblastoma. Longer follow-up on a larger number of patients is required to further demonstrate the utility of endoscopic approaches in the management of this malignancy.

Neurosurg Rev (2011) 34:363–371. DOI 10.1007/s10143-011-0309-6

Ventriculoperitoneal shunting is a widely accepted technique for the treatment of hydrocephalus. The standard procedure to insert the peritoneal catheter requires an abdominal incision, muscle dissection, and opening of the peritoneum. A number of complications related to the abdominal surgical phase have been reported. Laparoscopy-assisted ventriculoperitoneal shunting is a valid alternative procedure that reduces surgical trauma.

We describe our experience and review the literature. A total of 30 laparoscopically guided ventriculoperitoneal shunting procedures were performed between January 2007 and June 2008, in collaboration with a general surgeon experienced in laparoscopy. Of these procedures, 25 were new shunt placements and 5 were revisions. Data about operative time, outcome, and complications were registered and compared with a group of 30 patients treated by means of standard laparotomy in the period 2005–2007. Laparoscopic shunt placement was successful in all patients. Operative duration, complications, and postoperative pain were all lower in patients treated by laparoscopy as compared to the laparotomy. In the laparoscopic group, an earlier peristalsis, quicker mobilization, and better cosmetic results were also noted.

Laparoscopy in both ventriculoperitoneal shunt placement and revision is a safe, effective, and minimally invasive technique. It ensures proper abdominal placement of the distal catheter under direct vision allowing confirmation of its patency.

Neurosurgery 69:135–144, 2011 DOI: 10.1227/NEU.0b013e318214a98c

Transmuscular tubular diskectomy has been introduced to increase the rate of recovery, although evidence is lacking.

OBJECTIVE: To evaluate the 2-year results of tubular diskectomy compared with conventional microdiskectomy.

METHODS: Three hundred twenty-eight patients with persistent leg pain caused by lumbar disk herniation were randomly assigned to undergo tubular diskectomy (167 patients) or conventional microdiskectomy (161 patients). Main outcome measures were scores from Roland-Morris Disability Questionnaire for Sciatica, Visual Analog Scale for leg pain and low-back pain, and Likert self-rating scale of global perceived recovery.

RESULTS: On the basis of intention-to-treat analysis, there was no significant difference between tubular diskectomy and conventional microdiskectomy in Roland-Morris Disability Questionnaire for Sciatica scores during 2 years after surgery (between-group mean difference [∆] = 0.6; 95% confidence interval [CI], 20.3-1.6). Patients treated with tubular diskectomy reported more leg pain (∆ = 3.3 mm; 95% CI, 0.2-6.2) and more lowback pain (∆ = 3.0 mm; 95% CI, 20.2-6.3) than those patients treated with conventional microdiskectomy. At 2 years, 71% of patients assigned to tubular diskectomy documented a good recovery vs 77% of patients assigned to conventional microdiskectomy (odds ratio, 0.76; 95% CI, 0.45-1.28; P = .35). Repeated surgery rates within 2 years after tubular diskectomy and conventional microdiskectomy were 15% and 10%, respectively (P = .22).

CONCLUSION: Tubular diskectomy and conventional microdiskectomy resulted in similar functional and clinical outcomes. Patients treated with tubular diskectomy reported more leg pain and low-back pain, although the differences were small and not clinically relevant.

J Neurosurg 115:11–17, 2011. DOI: 10.3171/2011.2.JNS101451

Accurate discrimination between tumor and normal tissue is crucial for optimal tumor resection. Qualitative fluorescence of protoporphyrin IX (PpIX), synthesized endogenously following d-aminolevulinic acid (ALA) administration, has been used for this purpose in high-grade glioma (HGG). The authors show that diagnostically significant but visually imperceptible concentrations of PpIX can be quantitatively measured in vivo and used to discriminate normal from neoplastic brain tissue across a range of tumor histologies.

Methods. The authors studied 14 patients with diagnoses of low-grade glioma (LGG), HGG, meningioma, and metastasis under an institutional review board–approved protocol for fluorescence-guided resection. The primary aim of the study was to compare the diagnostic capabilities of a highly sensitive, spectrally resolved quantitative fluorescence approach to conventional fluorescence imaging for detection of neoplastic tissue in vivo.

Results. A significant difference in the quantitative measurements of PpIX concentration occurred in all tumor groups compared with normal brain tissue. Receiver operating characteristic (ROC) curve analysis of PpIX concentration as a diagnostic variable for detection of neoplastic tissue yielded a classification efficiency of 87% (AUC = 0.95, specificity = 92%, sensitivity = 84%) compared with 66% (AUC = 0.73, specificity = 100%, sensitivity = 47%) for conventional fluorescence imaging (p < 0.0001). More than 81% (57 of 70) of the quantitative fluorescence measurements that were below the threshold of the surgeon’s visual perception were classified correctly in an analysis of all tumors.

Conclusions. These findings are clinically profound because they demonstrate that ALA-induced PpIX is a targeting biomarker for a variety of intracranial tumors beyond HGGs. This study is the first to measure quantitative ALA-induced PpIX concentrations in vivo, and the results have broad implications for guidance during resection of intracranial tumors.

Acta Neurochir (2011) 153:1361–1366. DOI 10.1007/s00701-011-1063-9

Aneurysms located at the middle cerebral artery bifurcation remain a clear neurosurgical indication. We detail here the steps necessary to enable safe surgery for Sylvian fissure aneurysms.

Methods: An angiogram with 3D reconstruction is obtained and reviewed intraoperatively, just prior to the skin incision. During the exposure, the cistern is kept open by small cottonoids, thereby avoiding brain retraction. Continuous monitoring of MEPs along with ICG microscopic angiofluorescence allows for detection of vascular compromise. Intraoperative angiography with 3D reconstruction allows for immediate correction of less than satisfactory surgical outcome.

Conclusions Careful planning of surgical strategy followed by a minimally invasive technique (with continuous neuro-monitoring) ensures safe surgery. The availability of intra-operative radiological guidance allows for optimal management.