David A. Wilson

Comparison of dural grafts in Chiari decompression surgery: Review of the literature.

Background: Decompression of Chiari malformation is a common procedure in both pediatric and adult neurosurgery. Although the necessity for some bony removal is universally accepted, other aspects of Chiari surgery are the subject of debate. The most controversial points include the optimal amount of bony removal, the use of duraplasty (and the type of material), the need for subarachnoid dissection, and the need for tonsillar shrinkage. Material and Methods: We critically reviewed the literature to elucidate the risks and benefits of different graft types and to clarify optimal treatment options therein. Based on our search results, 108 relevant articles were identified. With specific inclusion and exclusion criteria, we noted three studies that directly compared two tlpes of dural substitutes in Chiari malformation surgery. Results: Our review did not support the superiority of either autologous or nonautologous grafts when duraplasty is employed. Our institutional experience, however, dictates that when the pericranium is available and of good quality, it should be utilized for duraplasty. It is non-immunogenic, inexpensive, and capable of creating a watertight closure with the dura. Conclusions: Discrepancies between the three comparative studies analyzed are likely attributable to increases in pericranial quality and thickness with maturity. Future randomized studies with large numbers and the power to resolve differences in the relatively low rates of complications in Chiari surgery are warranted.

Cavernous malformations of the brainstem presenting in childhood: surgical experience in 40 patients.

BACKGROUND: Brainstem cavernous malformations (BSCMs) are believed to compose 9% to 35% of all cerebral cavernous malformations, but these lesions have been reported in children in very limited numbers. OBJECTIVE: To review surgical outcomes of pediatric patients with BSCMs treated at 1 institution. METHODS: We retrospectively analyzed the course of 40 pediatric patients (19 males, 21 females; age range, 10 months to 18.9 years; mean, 12.3 years) who underwent surgery between 1984 and 2009. Age, sex, presenting symptoms, location of lesion, surgical approach, new postoperative deficits, Glasgow Outcome Scale score, recurrences, and resolution of baseline symptoms were recorded. RESULTS: Thirty-nine patients experienced hemorrhage before surgery. Lesion locations included the pons (n = 22), midbrain (n = 4), midbrain and thalamus (n = 4), pontomesencephalic junction (n = 3), medulla (n = 3), pontomedullary junction (n = 3), and cervicomedullary junction (n = 1). Mean lesion size was 2.3 cm. Mean length of hospital stay was 10.7 days. The average clinical follow-up was 31.9 months in 36 patients with follow-up after discharge. At last follow-up, 5 patients had experienced symptoms and/or imaging consistent with rehemorrhage, either from a residual that enlarged or true recurrence (5.25% annual rebleed risk per patient after surgery); 2 required reoperation for further resection of cavernoma. Mean Glasgow Outcome Scale score was 4.2 on admission, 4.05 at discharge, and 4.5 at latest follow-up. Preoperative symptoms and deficits improved in 16 patients (40%). New neurological deficits developed in 19 patients (48%) and resolved in 9, leaving 10 patients (25%) with new permanent deficit. CONCLUSION: Compared with adults, pediatric patients with BCSMs tend to have larger lesions and higher rates of recurrence (regrowth of residual lesion). Given the greater life expectancy of children, surgical treatment seems warranted in those with surgically accessible lesions that have bled. Outcomes were similar to those in our adult series of patients with BSCMs.

The relationship between ruptured aneurysm location, subarachnoid hemorrhage clot thickness, and incidence of radiographic or symptomatic vasospasm in patients enrolled in a prospective randomized controlled trial

OBJECTnCerebral vasospasm following subarachnoid hemorrhage (SAH) causes significant morbidity in a delayed fashion. The authors recently published a new scale that grades the maximum thickness of SAH on axial CT and is predictive of vasospasm incidence. In this study, the authors further investigate whether different aneurysm locations result in different SAH clot burdens and whether any concurrent differences in ruptured aneurysm location and maximum SAH clot burden affect vasospasm incidence.nnnMETHODSnTwo hundred fifty patients who were part of a prospective randomized controlled trial were reviewed. Most outcome and demographic variables were included as part of the prospective randomized controlled trial. Additional variables were also collected at a later time, including vasospasm data and maximum clot thickness.nnnRESULTSnAneurysms were categorized into 1 of 6 groups: intradural internal carotid artery aneurysms, vertebral artery (VA) aneurysms (including the posterior inferior cerebellar artery), basilar trunk or basilar apex aneurysms, middle cerebral artery aneurysms, pericallosal aneurysms, and anterior communicating artery aneurysms. Twenty-nine patients with nonaneurysmal SAH were excluded. Patients with pericallosal aneurysms had the least average maximum clot burden (5.3 mm), compared with 6.4 mm for the group overall, but had the highest rate of symptomatic vasospasm (56% vs 22% overall, OR 4.9, RR 2.7, p = 0.026). Symptomatic vasospasm occurrence was tallied in patients with clinical deterioration attributable to delayed cerebral ischemia. There were no significant differences in maximum clot thickness between aneurysm sites. Middle cerebral artery aneurysms resulted in the thickest mean maximum clot (7.1 mm) but rates of symptomatic and radiographic vasospasm in this group were statistically no different compared with the overall group. Vertebral artery aneurysms had the worst 1-year modified Rankin scale (mRS) scores (3.0 vs 1.9 overall, respectively; p = 0.0249). A 1-year mRS score of 0-2 (good outcome) was found in 72% of patients overall, but in only 50% of those with pericallosal and VA aneurysms, and in 56% of those with basilar artery aneurysms (p = 0.0044). Patients with stroke from vasospasm had higher mean clot thickness (9.71 vs 6.15 mm, p = 0.004).nnnCONCLUSIONSnThe location of a ruptured aneurysm minimally affects the maximum thickness of the SAH clot but is predictive of symptomatic vasospasm or clinical deterioration from delayed cerebral ischemia in pericallosal aneurysms. The worst 1-year mRS outcomes in this cohort of patients were noted in those with posterior circulation aneurysms or pericallosal artery aneurysms. Patients experiencing stroke had higher mean clot burden.

Multimodality treatment of conus medullaris arteriovenous malformations: 2 decades of experience with combined endovascular and microsurgical treatments.

BACKGROUNDnConus medullaris arteriovenous malformations (AVMs) are rare, challenging spinal vascular lesions that cause progressive debilitating myeloradiculopathy. Only sporadic reports of conus AVMs have been published.nnnOBJECTIVEnTo better define the presentation, prognosis, and optimal treatment of these lesions, we present the first case series of conus AVMs, reflecting over 2 decades of experience with a multimodality endovascular and surgical approach.nnnMETHODSnWe retrospectively reviewed the charts of 16 patients with a conus AVM evaluated at our institution from 1989 to 2010. For each patient, the following clinical data were collected: age, sex, symptoms, angiographic findings, type of treatment, complications, degree of angiographic obliteration, recurrence at follow-up, and need for re-treatment. Ambulatory status, Frankel Grade, motor function, and bladder/bowel function were assessed before treatment, at discharge, and at last follow-up.nnnRESULTSnAll 16 patients were treated. Eight (50%) patients underwent embolization followed by microsurgical resection, and 8 (50%) underwent microsurgical resection only. The rate of complete angiographic obliteration was 88%. At last follow-up (mean, 70 months), 43% of patients neurologically improved, 43% were stable, and 14% worsened in comparison with before treatment. During follow-up, 3 recurrences were detected, including the only 2 instances of long-term neurological decline. In the absence of recurrence, all patients ambulatory before treatment remained ambulatory at follow-up, whereas 75% of the initially nonambulatory patients regained the ability to walk.nnnCONCLUSIONnAlthough conus AVMs are challenging to treat, excellent long-term outcomes are possible with a multimodality approach. Recurrence is associated with long-term neurological decline and calls for close follow-up.

Survival and Functional Outcome After Surgical Resection of Intramedullary Spinal Cord Metastases

OBJECTIVEnIntramedullary spinal cord metastasis (ISCM) is a rare manifestation of systemic cancer and data about the optimal management of these lesions are lacking. To clarify the role of surgery, we investigated survival and neurological outcomes after surgical resection of ISCMs.nnnMETHODSnBetween 2003 and 2010, we surgically treated 10 ISCMs in 9 patients. For each patient, we retrospectively collected the following data: demographic variables, history of prior cancer, site of primary cancer, extent of cancer on presentation, degree of resection, preoperative and postoperative spinal cord impairment (American Spinal Injury Association [ASIA] grade), and postoperative survival. We investigated the relationship between these variables, overall survival, and preservation of function.nnnRESULTSnEight ISCMs were treated with gross total resection and two were treated with subtotal resection. Overall postoperative survival was 6.4 ± 9.4 months (mean ± standard deviation), with one patient still alive at last follow-up. Patients with a diagnosis of melanoma had higher mean survival than those with nonmelanoma histology (20.5 ± 13.4 vs. 2.4 ± 1.7 months, P < 0.01). Degree of resection, number of organ systems affected, ambulatory status, and ASIA grade pre operatively or postoperatively, were not significantly associated with survival. Of the nine patients, seven (78%) demonstrated no change in ASIA grade postoperatively, one (11%) improved, and one patient (11%) deteriorated. All patients who were ambulatory preoperatively remained ambulatory postoperatively and at last follow-up.nnnCONCLUSIONSnAlthough ISCM is associated with poor prognosis, survival appears to be greater in patients with melanoma. Surgical resection does not appear to significantly lengthen survival but may be indicated to preserve ambulatory status in symptomatic patients.

Endoscopic Resection of Colloid Cysts: Use of a Dual-Instrument Technique and an Anterolateral Approach

OBJECTIVEnEndoscopic approaches are increasingly utilized to treat third ventricular colloid cysts but have been associated with lower rates of complete cyst wall resection. Our objective was to assess the results of colloid cyst resection via an anterolateral endoscopic approach with a dual-instrument technique, with an emphasis on completeness of cyst wall resection.nnnMETHODSnA retrospective review of the senior authors experience with 22 colloid cysts treated with endoscopic resection since 2004 was performed. Initial cyst size, completeness of resection, postoperative radiographic residual, recurrence at follow-up, need for reoperation, and neurologic morbidity were assessed. All cysts were approached from an anterolateral trajectory with two instruments working in concert through a single endoscope.nnnRESULTSnOf 22 patients, near-total resection was obtained in 95%. In 3 cases, a very small, radiographically occult residual was left. Complete cyst wall resection was therefore obtained in 18 (82%). There were no cases of recurrence at follow-up in any patient. No patients required craniotomy or underwent re-resection. Fifteen of 16 (94%) patients with long-term clinical follow-up remained stable or improved.nnnCONCLUSIONnHigh rates of complete colloid cyst resection, with low morbidity, are possible with an anterolateral endoscopic approach with dual-instrument technique. These results support the findings of other endoscopists that show how technical modifications to traditional endoscopic approaches can produce favorable results.

Time course of recovery following poor-grade SAH: the incidence of delayed improvement and implications for SAH outcome study design

OBJECTnData regarding the time course of recovery after poor-grade subarachnoid hemorrhage (SAH) is lacking. Most SAH studies assess outcome at a single time point, often as early as 3 or 6 months following SAH. The authors hypothesized that recovery following poor-grade SAH is a dynamic process and that early outcomes may not always approximate long-term outcomes. To test this hypothesis, they analyzed long-term outcome data from a cohort of patients with poor-grade aneurysmal SAH to determine the incidence and predictors of early and delayed neurological improvement.nnnMETHODSnThe authors reviewed outcome data from 88 poor-grade SAH patients enrolled in a prospective SAH treatment trial (the Barrow Ruptured Aneurysm Trial). They assessed modified Rankin Scale (mRS) scores at discharge, 6 months, 12 months, and 36 months after treatment to determine the incidence and predictors of neurological improvement during each interval.nnnRESULTSnThe mean aggregate mRS scores at 6 months (3.31 ± 2.1), 12 months (3.28 ± 2.2), and 36 months (3.17 ± 2.3) improved significantly compared with the mean score at hospital discharge (4.33 ± 1.3, p < 0.001), but they did not differ significantly among themselves. Between discharge and 6 months, 61% of patients improved on the mRS. The incidence of improvement between 6-12 months and 12-36 months was 18% and 19%, respectively. Hunt and Hess Grade IV versus V (OR 6.20, 95% CI 2.11-18.25, p < 0.001) and the absence of large (> 4 cm) (OR 2.76, 95% CI 1.02-7.55, p = 0.05) or eloquent (OR 5.17, 95% CI 1.89-14.10, p < 0.01) stroke were associated with improvement up to 6 months. Age ≤ 65 years (OR 5.56, 95% CI 1.17-26.42, p = 0.02), Hunt and Hess Grade IV versus V (OR 4.17, 95% CI 1.10-15.85, p = 0.03), and absence of a large (OR 8.97, 95% CI 2.65-30.40, p < 0.001) or eloquent (OR 4.54, 95% CI 1.46-14.08, p = 0.01) stroke were associated with improvement beyond 6 months. Improvement beyond 1 year was most strongly predicted by the absence of a large stroke (OR 7.62, 95% CI 1.55-37.30, p < 0.01).nnnCONCLUSIONSnA substantial minority of poor-grade SAH patients will experience delayed recovery beyond the point at which most studies assess outcome. Younger patients, those presenting in better clinical condition, and those without CT evidence of large or eloquent stroke demonstrated the highest capacity for delayed recovery.

Orbitozygomatic resection for hypothalamic hamartoma and epilepsy: patient selection and outcome

PurposeThis study aims to examine the outcomes of ten patients after orbitozygomatic (OZ) pterional surgery in cases of refractory epilepsy caused by hypothalamic hamartomas (HH).MethodsTen patients with HH and treatment-resistant epilepsy (mean age 18.3xa0years, range 0.7 to 42.7) underwent HH resection with an OZ approach (nu2009=u20098) or an OZ approach combined with a transventricular endoscopic approach (nu2009=u20092). Follow-up for the patients ranged from 0.5 to 6.2xa0years (mean 3.1). Outcomes were prospectively monitored with the use of a proprietary database.ResultsFour patients (40%) are seizure-free, and four (40%) have had greater than 50% reduction in seizures. One patient had no significant change in seizure frequency, and one patient died unexpectedly 2.8xa0years after surgery. Six patients had total or near-total HH resection (98–100% of HH lesion volume). Of these, four of six (66%) were seizure-free, and two had at least greater than 50% reduction in seizures. Residual complications include diabetes insipidus (nu2009=u20091), poikilothermia (nu2009=u20091), visual field deficit (nu2009=u20091), and hemiparesis (nu2009=u20091). Eight families (80%) reported improved quality of life.ConclusionsPatients with treatment-resistant epilepsy and tumors with an inferior or horizontal plane of attachment to the hypothalamus should continue to be approached from below. Those with both intrahypothalamic and parahypothalamic components may require approaches from above and below, either simultaneously or staged. For appropriately selected patients, the success of controlling seizures with an OZ is comparable to results utilizing transcallosal or transventricular approaches. The likelihood of controlling seizures appears to correlate with extent of resection.

Clinical characteristics and long-term outcomes in patients with ruptured posterior inferior cerebellar artery aneurysms: a comparative analysis

OBJECTnSubarachnoid hemorrhage (SAH) from ruptured posterior inferior cerebellar artery (PICA) aneurysms is uncommon, and long-term outcome data for patients who have suffered such hemorrhages is lacking. This study investigated in-hospital and long-term clinical data from a prospective cohort of patients with SAH from ruptured PICA aneurysms enrolled in a randomized trial; their outcomes were compared with those of SAH patients who were treated for other types of ruptured intracranial aneurysms. The authors hypothesize that PICA patients fare worse than those with aneurysms in other locations and this difference is related to the high rate of lower cranial nerve dysfunction in PICA patients.nnnMETHODSnThe authors analyzed data for 472 patients enrolled in the Barrow Ruptured Aneurysm Trial (BRAT) and retrospectively reviewed vasospasm data not collected prospectively. In the initial cohort, 57 patients were considered angiographically negative for aneurysmal SAH source and did not receive treatment for aneurysms, leaving 415 patients with aneurysmal SAH.nnnRESULTSnOf 415 patients with aneurysmal SAH, 22 (5.3%) harbored a ruptured PICA aneurysm. Eight of them had dissecting/fusiform-type aneurysms while 14 had saccular-type aneurysms. Nineteen PICA patients were treated with clipping (1 crossover from coiling), 2 were treated with coiling, and 1 died before treatment. When comparing PICA patients to all other aneurysm patients in the study cohort, there were no statistically significant differences in age (mean 57.6 ± 11.8 vs 53.9 ± 11.8 years, p = 0.17), Hunt and Hess grade median III [IQR II-IV] vs III [IQR II-III], p = 0.15), Fisher grade median 3 [IQR 3-3] vs 3 [IQR 3-3], p = 0.53), aneurysm size (mean 6.2 ± 3.0 vs 6.7 ± 4.0 mm, p = 0.55), radiographic vasospasm (53% vs 50%, p = 0.88), or clinical vasospasm (12% vs 23%, p = 0.38). PICA patients were more likely to have a fusiform aneurysm (36% vs 12%, p = 0.004) and had a higher incidence of lower cranial nerve dysfunction and higher rate of tracheostomy/percutaneous endoscopic gastrostomy placement compared with non-PICA patients (50% vs 16%, p < 0.001). PICA patients had a significantly higher incidence of poor outcome at discharge (91% vs 67%, p = 0.017), 1-year follow-up (63% vs 29%, p = 0.002), and 3-year follow-up (63% vs 32%, p = 0.006).nnnCONCLUSIONSnPatients with ruptured PICA aneurysms had a similar rate of radiographic vasospasm, equivalent admission Fisher grade and Hunt and Hess scores, but poorer clinical outcomes at discharge and at 1- and 3-year follow-up when compared with the rest of the BRAT SAH patients with ruptured aneurysms. The PICAs location at the medulla and the resultant high rate of lower cranial nerve dysfunction may play a role in the poor outcome for these patients. Furthermore, PICA aneurysms were more likely to be fusiform than saccular, compared with non-PICA aneurysms; the complex nature of these aneurysms may also contribute to their poorer outcome.

Comparative Analysis of Surgical Freedom and Angle of Attack of Two Minimal-Access Endoscopic Transmaxillary Approaches to the Anterolateral Skull Base

OBJECTIVEnSurgical freedom and the angle of attack influence approach selection for open cranial base approaches, but these concepts have not been well studied in minimal-access endoscopic approaches. We therefore developed a methodology to study surgical freedom and angle of attack in two endoscopic transmaxillary transpterygoid approaches, the endonasal ipsilateral uninostril medial maxillotomy and the sublabial Caldwell-Luc anterior maxillotomy.nnnMETHODSnDissections were performed bilaterally in three formalin-fixed cadaver heads (six sides). For each approach, three progressively lateral and posterior anatomic targets were identified. Utilizing frameless stereotaxy, surgical freedom using the vector cross-product method was calculated for both approaches for each target. The mean and maximum possible angles of attack were calculated in the axial and sagittal planes.nnnRESULTSnCompared to the endoscopic endonasal-transmaxillary approach, the endoscopic Caldwell-Luc approach offered significantly greater surgical freedom to the genu of the internal carotid artery (P=0.02), foramen rotundum (P=0.03), and foramen ovale (P=0.03). Mean and maximum possible angles of attack were also significantly different between the two approaches for each target. The Caldwell-Luc approach offered a more bottom-up approach in the sagittal plane and a more head-on approach in the axial plane to each target (P<0.05).nnnCONCLUSIONSnWe have successfully developed a model for comparing endoscopic skull base approaches. Both the endonasal medial maxillotomy approach and Caldwell-Luc approach provided endoscopic access to each target. However, the sublabial Caldwell-Luc approach offered greater surgical freedom and a more head-on approach than the endonasal medial maxillotomy. These differences in surgical freedom and angles of attack may be useful to consider when planning minimal-access approaches.