Matthew R. Quigley

The Relationship between Survival and the Extent of the Resection in Patients with Supratentorial Malignant Gliomas

Current neurosurgical opinion favors the radical surgical removal of supratentorial gliomas, when feasible, in the belief that this optimizes patient survival. Although bolstered by the results of some early investigators, the efficacy of this approach remains debatable. Therefore, we undertook a review of the English language literature of the past 30 years for a series of surgically treated malignant gliomas. Twenty reports comprising 5691 patients were identified. Only 4 found the extent of the surgical resection related to survival. In 2 of these, it followed age, histological findings, and performance status in importance. The 2 other studies did not rank the prognostic variables at all. On closer inspection, however, there does appear to be a subgroup of young patients with favorable histological findings and good performance status for whom surgery is beneficial. Future reporting of surgical results of patients with gliomas will require stratification by the known prognostic variables of age, histological findings, and performance status to characterize better this subgroup for whom surgery is beneficial.

Stereotactic radiosurgery boost to the resection bed for oligometastatic brain disease: challenging the tradition of adjuvant whole-brain radiotherapy.

OBJECTnWhole-brain radiation therapy (WBRT) has been the traditional approach to minimize the risk of intracranial recurrence following resection of brain metastases, despite its potential for late neurotoxicity. In 2007, the authors demonstrated an equivalent local recurrence rate to WBRT by using stereotactic radiosurgery (SRS) to the operative bed, sparing 72% of their patients WBRT. They now update their initial experience with additional patients and more mature follow-up.nnnMETHODSnThe authors performed a retrospective review of all cases involving patients with limited intracranial metastatic disease (< or = 4 lesions) treated at their institution with SRS to the operative bed following resection. No patient had prior cranial radiation and WBRT was used only for salvage.nnnRESULTSnFrom November 2000 to June 2009, 52 patients with a median age of 61 years met inclusion criteria. A single metastasis was resected in each patient. Thirty-four of the patients each had 1 lesion, 13 had 2 lesions, 3 had 3 lesions, and 2 had 4 lesions. A median dose of 1500 cGy (range 800-1800 cGy) was delivered to the resection bed targeting a median volume of 3.85 cm(3) (range 0.08-22 cm(3)). With a median follow-up of 13 months, the median survival was 15.0 months. Four patients (7.7%) had a local recurrence within the surgical site. Twenty-three patients (44%) ultimately developed distant brain recurrences at a median of 16 months postresection, and 16 (30.7%) received salvage WBRT (8 for diffuse disease [> 3 lesions], 4 for local recurrence, and 4 for diffuse progression following salvage SRS). The median time to WBRT administration postresection was 8.7 months (range 2-43 months). On univariate analysis, patient factors of a solitary tumor (19.0 vs 12 months, p = 0.02), a recursive partitioning analysis (RPA) Class I (21 vs 13 months, p = 0.03), and no extracranial disease on presentation (22 vs 13 months, p = 0.01) were significantly associated with longer survival. Cox multivariate analysis showed a significant association with longer survival for the patient factors of no extracranial disease on presentation (p = 0.01) and solitary intracranial metastasis (p = 0.02). Among patients with no extracranial disease, a solitary intracranial metastasis conferred significant additional survival advantage (43 vs 10.5 months, p = 0.05, log-rank test). No factor (age, RPA class, tumor size or histological type, disease burden, extent of resection, or SRS dose or volume) was related to the need for salvage WBRT.nnnCONCLUSIONSnAdjuvant SRS to the metastatic intracranial operative bed results in a local recurrence rate equivalent to adjuvant WBRT. In combination with SRS for unresected lesions and routine imaging surveillance, this approach achieves robust overall survival (median 15 months) while sparing 70% of the patients WBRT and its potential acute and chronic toxicity.

Cerebrospinal Fluid Shunt Infections

All shunt procedures performed at our institution from July 1982 to December 1987 were analyzed for factors possibly related to shunt infection. There were 41 infections detected in 31 patients for an overall rate of 6.9%. Only intraventricular hemorrhage (IVH) as an etiology of the hydrocephalus and internalization of an external ventricular drain (EVD) were found to correlate with septic risk. An extensive review of all the English language literature concerning shunt infections over the last 15 years was undertaken. Little consensus could be found among the 35 publications in regard to factors predisposing to shunt sepsis. Even the issue of antibiotic prophylaxis remains clouded as all papers examined exhibited methodologic flaws.

Single session stereotactic radiosurgery boost to the post-operative site in lieu of whole brain radiation in metastatic brain disease.

Purpose Whole brain radiation (WBXRT) reduces the incidence of local and distant recurrence following resection of metastatic brain disease but does not prolong life and may entail neurocognitive decline. We employed a novel treatment modality of providing a single-session stereotactic radiosurgery (SRS) boost to the surgical resection site to achieve local control without the risk of cognitive effects. Methods We reviewed all patients at our institution that were treated with SRS to the post-operative bed following resection of a metastatic brain deposit. Results There were 32 patients identified (16 F) and median age was 60xa0years. One lesion was resected in all patients of whom 21 were solitary (eight with two lesions, three with three). Median survival was 16.4xa0months with a 14xa0month median follow-up. Factors which improved survival were solitary tumor, age <65 and RPA 1, although none achieved statistical significance. In the Cox multivariate analysis only smaller post-operative treatment volume correlated with survival (Pxa0=xa0.04). There were two local recurrences (6.25%) to the surgical site and four patients required SRS for new lesions. Nine patients ultimately required salvage WBXRT (3/21 solitary v. 6/11 multiple lesions, Pxa0=xa0.03 χ2), two for local recurrence post resection and seven for diffuse new disease. Conclusion The use of SRS to the surgical site results in local recurrence rates comparable to WBXRT and is associated with excellent survival. Over 70% of patients managed this way were spared WBXRT. The presence of multiple lesions on presentation is predictive of the need for subsequent salvage WBXRT.

Role of biofilms in neurosurgical device-related infections

Bacterial biofilms have recently been shown to be important in neurosurgical device-related infections. Because the concept of biofilms is novel to most practitioners, it is important to understand that both traditional pharmaceutical therapies and host defense mechanisms that are aimed at treating or overcoming free-swimming bacteria are largely ineffective against the sessile bacteria in a biofilm. Bacterial biofilms are complex surface-attached structures that are composed of an extruded extracellular matrix in which the individual bacteria are embedded. Superimposed on this physical architecture is a complex system of intercellular signaling, termed quorum sensing. These complex organizational features endow biofilms with numerous microenvironments and a concomitant number of distinct bacterial phenotypes. Each of the bacterial phenotypes within the biofilm displays a unique gene expression pattern tied to nutrient availability and waste transport. Such diversity provides the biofilm as a whole with an enormous survival advantage when compared to the individual component bacterial cells. Thus, it is appropriate to view the biofilm as a multicellular organism, akin to metazoan eukaryotic life. Bacterial biofilms are much hardier than free floating or planktonic bacteria and are primarily responsible for device-related infections. Now that basic research has demonstrated that the vast majority of bacteria exist in biofilms, the paradigm of biofilm-associated chronic infections is spreading to the clinical world. Understanding how these biofilm infections affect patients with neurosurgical devices is a prerequisite to developing strategies for their treatment and prevention.

Cryosurgery re-visited for the removal and destruction of brain, spinal and orbital tumours.

Advances in neuroimaging and cryosurgical techniques have prompted us to re-evaluate the potential of cryosurgical techniques for the removal and the destruction of various neoplasms. We have used cryosurgical instrumentation to remove tumours in the brain, spine and orbit in 71 patients without complications. Cryosurgery was used to facilitate removal and extraction in 64 and to destroy residual neoplasms when removal was incomplete in 7. Intraoperative real time ultrasonic imaging permitted precise delimitation of tumours from surrounding tissues and allowed monitoring during the production of cryosurgical lesions thus permitting heretofore unavailable visualization of the production of cryogenic lesions in the central nervous system. New cryosurgical instrumentation was used to produce lesions up to three times larger than similar sized probes previously available. Our results reconfirm that cryosurgery facilitates the removal of tumours in the brain, spinal cord and orbit, reduces blood loss in vascular tumours, and is effective in ablating residual neoplasms involving the superior sagittal sinus, torcula and parasagittal areas. A Doppler flowmeter proved useful for monitoring sagittal sinus blood flow during the production of cryosurgical ablation of residual tumour attached to the walls of the sagittal sinus. Recent advances in ultrasonic and neuroimaging coupled with stereotactic techniques and improvements in cryosurgical instrumentation may prove useful in the future percutaneous destruction of selective intracranial neoplasms.

Primary treatment of a blister-like aneurysm with an encircling clip graft: technical case report.

OBJECTIVE: Blister-like aneurysms at nonbranching sites in the supraclinoid portion of the internal carotid artery are a rare but important cause of subarachnoid hemorrhage. We report a case of subarachnoid hemorrhage caused by a ruptured blister-type aneurysm, review the pertinent literature, and hope to remind readers of the wisdom of the use of an encircling clip as the primary treatment of these challenging lesions. CLINICAL PRESENTATION: A 41-year-old woman presented with sudden onset of headache. An admission computed tomographic (CT) scan revealed thick and diffuse subarachnoid hemorrhage involving primarily the carotid cistern and the proximal left sylvian fissure. A cerebral angiogram was initially interpreted as absent for aneurysm, but a follow-up angiogram performed 1 week later confirmed an enlarging aneurysm. INTERVENTION: A craniotomy with placement of an encircling clip graft around a blister-like aneurysm was performed. CONCLUSION: Although Sundt advocated the encircling clip graft for the blister-type aneurysm almost 40 years ago, use of an encircling clip graft in the treatment of blister-like aneurysms of the supraclinoid portion of the internal carotid artery seems to be reserved as a secondary or “rescue” measure in current practice. Neurosurgeons must familiarize themselves with this distinct entity (the blister-type aneurysm), recognize the possible risks associated with parallel clipping, and consider the use of an encircling clip graft as the primary treatment.

Direct demonstration of Staphylococcus biofilm in an external ventricular drain in a patient with a history of recurrent ventriculoperitoneal shunt failure.

External ventricular drains (EVD) are associated with a high infection rate. Early detection of infection is frequently problematic due to a lack of clinical signs and the time period required for culturing. Bacterial biofilms have been suggested to play an important role in the infection of EVD, but direct evidence is as yet lacking. We report the case of a 17- year-old male with Dandy-Walker malformation who presented with headache, nausea and drowsiness; a CT scan revealed enlarged ventricles. The patient had a history of ventriculoperitoneal shunt revision 3 weeks prior to admission. The shunt was removed on suspicion of infection and an EVD placed. Daily surveillance cultures through the EVD were negative and the EVD was replaced on day 5. Examination of the initial EVD by confocal microscopy demonstrated clear intraluminal biofilm formation; molecular analysis by PCR identified Staphylococcus aureus resident on the catheter. To our knowledge, this is the first direct demonstration of an intraluminal biofilm compromising an EVD. Despite the presence of biofilm on this catheter, the patient demonstrated no clinical signs of infection, and the routine surveillance culture was negative. Undetected biofilm may pose a latent risk on EVD and other neurosurgical catheters.

Surgical Complications of Deep Brain Stimulation

Background/Aims: Deep brain stimulation is a commonly performed procedure for intractable movement disorders. In this report we analyze the complications of a single surgeon at one institution over a 10-year period. Methods: A total of 191 patients received 330 electrode implants. Data was collected prospectively and analyzed retrospectively for the type and rate of complications. Results: The mean follow-up was 58.5 months. The overall surgical complication rate was 17.8% (59 complications in 330 implantations). These 59 complications involved 53 of 191 patients. The overall incidence of minor wound problems (hardware not removed), major wound problems (hardware removed) and hardware-related problems was 4.2% each, based on the total number of systems implanted. In addition 2.1% of the patients suffered minor bleeds while 1.6% had bleeds large enough to cause neurological deficits. The same percentage of patients (1.6%) either failed to benefit from the procedure or suffered complications unrelated to the procedure. A further 4/191 (2.1%) patients had neurological deficits without obvious hemorrhage on postoperative nonenhanced computerized tomography. Analysis of our complications from year to year shows a declining complication rate related to accumulated experience and better hardware design. Conclusion: Surgeon experience and hardware improvements have significantly reduced complications over time.

Lumbar Surgery in the Elderly

By virtue of modern neuroimaging, neurosurgeons are increasingly confronted by patients once deemed too old for lumbar corrective procedures. Management of these patients is problematic, as the literature is relatively mute in regard to results and complications within this elderly cohort. We, therefore, reviewed all surgical procedures for benign lumbar disease at two large metropolitan hospitals from January 1986 to June 1988 for patients greater than or equal to 70 years of age. There were 155 procedures performed on 143 patients (male:female, 48:95); the average age of the patients was 74.9 +/- 8.8 years; there were 32 cases of herniated disc, 29 cases of disc plus hypertrophic ligament/bone, and 94 cases of lateral recess/stenosis alone. Hospital stay averaged 7.5 +/- 3.5 days, and increasing age did not correlate with an extended admission. Major morbidity was low (6.9%), and there were no deaths. At follow-up, an average of 34.3 +/- 12.2 months postoperatively, 66.6% (56 of 84) of the patients reported no or minimal discomfort, whereas 15.4% (13 of 84) had not improved at all. Overall, 77.3% (65/84) were pleased with their procedure. These data represent the most comprehensive review in the literature of lumbar procedures in the elderly and indicate that these operations may be undertaken in this population with acceptable morbidity and a reasonable expectation of clinical improvement.