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The influence of cranioplasty on postural blood flow regulation, cerebrovascular reserve capacity, and cerebral glucose metabolism

Peter A. Winkler, Walter Stummer, Rainer Linke, Kartik G. Krishnan, and Klaus Tatsch

The indications for cranioplasty after decompressive craniectomy are cosmetic repair and, mainly, restoration of cerebral protection. Although neurological improvement after cranioplasty is repeatedly noted, the reasons for this still remain unclear. Few observations concerning the impact of CSF hydrodynamic and/or atmospheric pressure were published during the last decades. Relevant data concerning the cerebrovascular reserve capacity and cerebral glucose metabolism before and after cranioplasty have been lacking until now. To gain further insight, the present study was undertaken to investigate the impact of cranioplasty on indices of cerebral blood flow regulation and metabolism.

Thirteen patients in whom extensive craniectomies had been performed underwent a meticulous study of blood flow velocities in the middle cerebral artery (MCA) and extracranial internal carotid artery (ICA), as assessed by transcranial Doppler (TCD) ultrasonography during postural maneuvers (supine and sitting positions) and during stimulation with 1 g of acetazolamide for the interpretation of cerebrovascular reserve (CVR) capacity. Twelve patients underwent 18-fluorodesoxyglucose positron emission tomography. These measurements were made before and 7 days after cranioplasty.

Cranioplasty improved preoperative differences in MCA blood flow velocities when comparing the injured with the noninjured hemisphere. Similarly, cranioplasty resolved decreases in extracranial ICA blood flow in the injured hemisphere that were induced by postural changes, which was a constant finding prior to this procedure. More strikingly, however, the CVR capacity, which was severely impaired in both hemispheres, significantly increased after the procedure. Metabolic deficits, which were observed in the injured as compared with the noninjured hemisphere, were found to improve after reimplantation of the skull bone flap.

Cranioplasty appears to affect postural blood flow regulation, CVR capacity, and cerebral glucose metabolism markedly. Thus, early cranioplasty is warranted to facilitate rehabilitation in patients after decompressive craniectomy.

In Neurosurgical Focus Volume 8: Issue 1 (Jan 2000): Head Injury

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Hemispherectomy for treatment of refractory epilepsy in the pediatric age group: a systematic review

Christoph J. Griessenauer, Smeer Salam, Philipp Hendrix, Daxa M. Patel, R. Shane Tubbs, Jeffrey P. Blount, and Peter A. Winkler

OBJECT

Evidence in support of hemispherectomy stems from a multitude of retrospective studies illustrating individual institutions' experience. A systematic review of this topic, however, is lacking in the literature.

METHODS

A systematic review of hemispherectomy for the treatment of refractory epilepsy available up to October 2013 was performed using the following inclusion criteria: reports of a total of 10 or more patients in the pediatric age group (≤ 20 years) undergoing hemispherectomy, seizure outcome reported after a minimum follow-up of 1 year after the initial procedure, and description of the type of hemispherectomy. Only the most recent paper from institutions that published multiple papers with overlapping study periods was included. Two reviewers independently applied the inclusion criteria and extracted all the data.

RESULTS

Twenty-nine studies with a total of 1161 patients met the inclusion criteria. Seizure outcome was available for 1102 patients, and the overall rate of seizure freedom at the last follow-up was 73.4%. Sixteen studies (55.2%) exclusively reported seizure outcomes of a single type of hemispherectomy. There was no statistically significant difference in seizure outcome and type of hemispherectomy (p = 0.737). Underlying etiology was reported for 85.4% of patients with documented seizure outcome, and the overall distribution of acquired, developmental, and progressive etiologies was 30.5%, 40.7%, and 28.8%, respectively. Acquired and progressive etiologies were associated with significantly higher seizure-free rates than developmental etiologies (p < 0.001). Twenty of the 29 studies (69%) reported complications. The overall rate of hydrocephalus requiring CSF diversion was 14%. Mortality within 30 days was 2.2% and was not statistically different between types of hemispherectomy (p = 0.787).

CONCLUSIONS

Hemispherectomy is highly effective for treating refractory epilepsy in the pediatric age group, particularly for acquired and progressive etiologies. While the type of hemispherectomy does not have any influence on seizure outcome, hemispherotomy procedures are associated with a more favorable complication profile.

In Journal of Neurosurgery: Pediatrics Volume 15 (2015): Issue 1 (Jan 2015)

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Pipeline Embolization Device for small paraophthalmic artery aneurysms with an emphasis on the anatomical relationship of ophthalmic artery origin and aneurysm

Christoph J. Griessenauer, Christopher S. Ogilvy, Paul M. Foreman, Michelle H. Chua, Mark R. Harrigan, Christopher J. Stapleton, Aman B. Patel, Lucy He, Matthew R. Fusco, J Mocco, Peter A. Winkler, Apar S. Patel, and Ajith J. Thomas

OBJECTIVE

Contemporary treatment for paraophthalmic artery aneurysms includes flow diversion utilizing the Pipeline Embolization Device (PED). Little is known, however, about the potential implications of the anatomical relationship of the ophthalmic artery (OA) origin and aneurysm, especially in smaller aneurysms.

METHODS

Four major academic institutions in the United States provided data on small paraophthalmic aneurysms (≤ 7 mm) that were treated with PED between 2009 and 2015. The anatomical relationship of OA origin and aneurysm, radiographic outcomes of aneurysm occlusion, and patency of the OA were assessed using digital subtraction angiography. OA origin was classified as follows: Type 1, OA separate from the aneurysm; Type 2, OA from the aneurysm neck; and Type 3, OA from the aneurysm dome. Clinical outcome was assessed using the modified Rankin Scale, and visual deficits were categorized as transient or permanent.

RESULTS

The cumulative number of small paraophthalmic aneurysms treated with PED between 2009 and 2015 at the 4 participating institutions was 69 in 52 patients (54.1 ± 13.7 years of age) with a male-to-female ratio of 1:12. The distribution of OA origin was 72.5% for Type 1, 17.4% for Type 2, and 10.1% for Type 3. Radiographic outcome at the last follow-up (median 11.5 months) was available for 54 aneurysms (78.3%) with complete, near-complete, and incomplete occlusion rates of 81.5%, 5.6%, and 12.9%, respectively. Two aneurysms (3%) resulted in transient visual deficits, and no patient experienced a permanent visual deficit. At the last follow-up, the OA was patent in 96.8% of treated aneurysms. Type 3 OA origin was associated with a lower rate of complete aneurysm occlusion (p = 0.0297), demonstrating a trend toward visual deficits (p = 0.0797) and a lower rate of OA patency (p = 0.0783).

CONCLUSIONS

Pipeline embolization treatment of small paraophthalmic aneurysms is safe and effective. An aneurysm where the OA arises from the aneurysm dome may be associated with lower rates of aneurysm occlusion, OA patency, and higher rates of transient visual deficits.

In Journal of Neurosurgery Volume 125 (2016): Issue 6 (Dec 2016)