Browse

You are looking at 1 - 10 of 10 items for

  • Refine by Access: all x
  • By Author: Winkler, Peter A. x
Clear All
Restricted access

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.

Restricted access

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.

Restricted access

Evaluation of new radiolucent polymer headholder pins for use in intraoperative computed tomography

Technical note

Ardeshir Ardeshiri, Christian Radina, Martin Edlauer, Ardavan Ardeshiri, Alfred Riepertinger, Andreas Nerlich, Jörg-Christian Tonn, and Peter A. Winkler

Object

With the introduction of intraoperative CT (iCT) scanning, neurosurgeons can now obtain images of the brain during surgery, offering the possibility of intraoperative resection control and monitoring of potential intraoperative complications. The combination of iCT with neuronavigation makes it possible to update the reference scans intraoperatively when necessary. However, the headholder pins normally used for iCT scanning still show artifacts. In the present study, new polymer pins, producing nearly no artifacts in laboratory tests, are compared with the usual pins with regard to their mechanical and artifact behavior to evaluate their potential use in the clinical routine.

Methods

Pins made of different materials (titanium, Macor, silicon nitride, zirconium oxide, sapphire, polyetheretherketone, and polyparaphenylene copolymer) were used for the fixation of 10 cadaveric heads. Special force sensors measured the fixation pressure of the pins, and histological analysis revealed the penetration depth. Computed tomography scans of a head phantom, fixed with the different pins, were obtained to reveal artifact behavior.

Results

All pins were biocompatible. Pins did not differ significantly in fixation pressures and mechanical behavior. Penetration depths were comparable (maximum 1.4 mm) and did not cause opening of the diploe. Polymer pins made of polyparaphenylene showed the best results in artifact behavior in CT scans.

Conclusions

The authors' results demonstrate that the new polymer pins are comparable in their mechanical behavior to the usual pins but superior in artifact behavior. Therefore, their use in the clinical routine of iCT scanning will be beneficial for the surgeon.

Restricted access

Otfrid Foerster, the great neurologist and neurosurgeon from Breslau (Wrocław): his influence on early neurosurgeons and legacy to present-day neurosurgery

Natalia Piotrowska and Peter A. Winkler

✓ As a result of the turbulences of World War II, Wrocław, Poland (formerly Breslau, Germany) lost its internationally acknowledged position in the field of neurosurgery, which it once had thanks to Otfrid Foerster. This innovative German doctor and scientist made a considerable contribution to the development of neurological and neurosurgical research worldwide. He also made Breslau a renowned center for scientific study, luring researchers from around the world. His achievements influenced many neurosurgeons during his lifetime, above all those from the US and England, including, for example, such well-known men as Fulton, Bucy, Bailey, and Penfield (who worked with Foerster in Breslau for quite a long time). Together Foerster and Penfield searched for the causes of epilepsy and the surgical methods to treat it. For young American neurosurgeons it was a very significant step in their careers to be able to train in Breslau under the guidance of Otfrid Foerster. In 1937 the British Association of Neurological Surgeons visited Breslau and awarded him with the honor of “Member Emeritus,” which could be seen as the culmination of Foerster's career.

In this paper the authors give an overview of Foerster's work and evaluate its significance. They also elucidate the difficult historical background during fascism in Germany using the sources of the Polish National Archives. Dr. Foerster's remaining traces in today's Wrocl/aw are meticulously reported.

Restricted access

Microsurgical anatomy of the mesencephalic veins

Ardavan Ardeshiri, Ardeshir Ardeshiri, Jennifer Linn, Jörg-Christian Tonn, and Peter A. Winkler

Object

The mesencephalic veins drain crucial brainstem areas. Due to the narrowness of the tentorial notch, these veins can become obstructed as a result of herniation or surgery, leading to hemorrhage and severe consequences for the patient. There is little in the literature about the mesencephalic veins. The aim of this study was to perform an exact analysis of their microanatomy.

Methods

Fifty-two cadaveric hemispheres were examined under an operating microscope, and measurements were made with a digital caliper. The authors focused on the basal vein (BV), pontomesencephalic vein (PMV), peduncular vein (PV), lateral mesencephalic vein (LMV), and other smaller veins.

The PMV was identified in 84.6% of specimens (mean diameter 0.54 mm); the PV, in 86.5% (mean diameter 0.86 mm); and the LMV, in 100% (mean diameter 1.07 mm). Four types of LMV were identified on the basis of the vein's course. Other smaller veins were also differentiated according to whether they drained mainly the cerebral peduncle, the lemniscal trigone, or the tectum. These veins and their junctions with other veins were depicted.

Conclusions

A thorough understanding of the microanatomy of the mesencephalic veins is crucial in brainstem surgery in order to avoid brain damage due to venous infarction and subsequent edema. Because knowledge of the course, variations, and outflow system of these veins could improve surgical outcome, they warrant special attention during surgery.

Restricted access

Transpetrosal Approach

G. Venkateswaraprasanna

Heading : Manas Panigrahi

Restricted access

Custom-tailored transdural anterior transpetrosal approach to ventral pons and retroclival regions

Hans-Jakob Steiger, Daniel Hänggi, Walter Stummer, and Peter A. Winkler

Object

The extradural anterior petrosectomy approach to the pons and midbasilar artery (mid-BA) has the main disadvantage that the extent of resection of the petrous apex cannot be as minimal as desired given that the surgical target field is not visible during bone removal. Unnecessary or excessive drilling poses the risk of injury to the internal carotid artery, vestibulocochlear organ, and seventh and eighth cranial nerves. The use of a custom-tailored transdural anterior transpetrosal approach can potentially avoid these pitfalls.

Methods

A technique for a transdural anterior petrosectomy was developed in the operating theater and anatomy laboratory. Following a subtemporal craniotomy and basal opening of the dura mater, the vein of Labbé is first identified and protected. Cerebrospinal fluid ([CSF] 50–100 ml) is drained via a spinal catheter. The tent is incised behind the entrance of the trochlear nerve toward the superior petrosal sinus (SPS), which is coagulated and divided. The dura is stripped from the petrous pyramid. Drilling starts at the petrous ridge and proceeds laterally and ventrally. The trigeminal nerve is unroofed. The internal acoustic meatus is identified and drilling is continued laterally as needed. The bone of the Kawase triangle toward the clivus can be removed down to the inferior petrosal sinus if necessary. Anterior exposure can be extended to the carotid artery if required. It is only exceptionally necessary to follow the greater superior petrosal nerve toward the geniculate ganglion and to expose the length of the internal acoustic canal.

The modified transdural anterior petrosectomy exposure has been used in nine patients—two with a mid-BA aneurysm, two with a dural arteriovenous fistula, one with a pontine glioma, three with a pontine cavernoma, and one with a pontine abscess. In one patient with a mid-BA aneurysm, subcutaneous CSF collection occurred during the postoperative period. No CSF fistula or approach-related cranial nerve deficit developed in any of these patients. There was no retraction injury or venous congestion of the temporal lobe nor any venous congestion due to the obliteration of the SPS or the petrosal vein.

Conclusions

The custom-made transdural anterior petrosectomy appears to be a feasible alternative to the formal extradural approach.

Restricted access

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

Object. 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 remain unclear. Few observations concerning the impact of cerebrospinal fluid hydrodynamic and/or atmospheric pressure have been published during the last decades. Relevant data concerning the cerebrovascular reserve (CVR) capacity and cerebral glucose metabolism before and after cranioplasty have been lacking until now. To gain further insight, this study was undertaken to investigate the impact of cranioplasty on indices of cerebral blood flow regulation and metabolism.

Methods. 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 ultrasonography during postural maneuvers (supine and sitting positions) and during stimulation with 1 g of acetazolamide for the interpretation of CVR capacity. Twelve patients underwent 18-fluorodeoxyglucose positron emission tomography. These measurements were obtained before and 7 days after cranioplasty.

Cranioplasty improved preoperative differences in MCA blood flow velocities when comparing those in the injured with those in the uninjured 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, increased significantly after the procedure. Metabolic deficits, which were observed in the injured hemisphere, were found to improve after reimplantation of the skull bone flap.

Conclusions. 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.

Restricted access

Colloid Cysts

Full access

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.