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Biomedical subjects

Robert F Spetzler

Publications and source records attributed to Robert F Spetzler.

At least 37 records · Page 2Linked to original sources
PubMed2006

Outcome of oculomotor nerve palsy from posterior communicating artery aneurysms: comparison of clipping and coiling.

OBJECTIVE: Recovery of posterior communicating artery aneurysm-induced oculomotor nerve palsy (ONP) after aneurysm coiling has been reported. However, the coil mass may compromise recovery of the nerve. Therefore, we compared the outcome of coiling and clipping for this indication. METHODS: We retrospectively compared the outcomes of ONP in 13 patients, six of whom underwent endovascular coiling and seven of whom underwent surgical clipping. RESULTS: Six of the seven surgical patients with ONP recovered completely, compared with two of the six patients in the endovascular group. Of the patients with more than 1 year of follow-up, all six surgical patients recovered completely, compared with two of four endovascular patients (P = 0.05). In addition, preoperative complete or partial ONP also was associated with degree of resolution by survival analysis (P = 0.03). All patients with partial ONP in the surgical group and two of three patients in the endovascular group recovered without residual deficits, whereas three of the four patients with complete ONP in the clipping group and none in the coiling group recovered completely. Regardless of the treatment method, time to complete resolution of ONP was 6 months in both groups. CONCLUSION: Clipping posterior communicating artery aneurysms was associated with a higher probability of complete recovery from ONP than coiling. Degree of preoperative ONP also affected recovery. If patients can tolerate surgery, it should be considered the treatment of choice.

Adult↗
PubMed2006

Postembolization neurological deficits in cerebral arteriovenous malformations: stratification by arteriovenous malformation grade.

OBJECTIVE: To stratify the risk of embolization during the treatment of cerebral arteriovenous malformations (AVMs) by grade and to assess its impact on the overall treatment risk. METHODS: Patients with cerebral AVMs treated with embolization between 1995 and 2004 were retrospectively reviewed. Age, sex, AVM grade, location of lesion, number and location of embolized arteries, and number of embolization sessions were analyzed with respect to neurological or vascular complications after embolization. RESULTS: Embolization was performed in 153 patients: 508 vessels were embolized during 203 sessions (mean, 3.3 vessels per patient). The mean angiographic and clinical follow-up periods were 1.7 and 2.1 years, respectively (range, 3-60 mo). The periprocedural morbidity and mortality rate was 11.8%, but at the last follow-up examination, only 2% of survivors were significantly disabled (modified Rankin score > 2). One (0.7%) patient died, and 17 patients experienced unexpected neurological deficits immediately after embolization. Five of these patients demonstrated near or total recovery during follow-up. The number of branches embolized was the only variable significantly related to neurological deficit (P < 0.017). The long-term rates of neurological deficits after embolization were 0, 5, 7, 10, and 18%, respectively, for AVM Grades I through V. Among 114 patients who underwent preoperative embolization, follow-up deficit rates of Grades I through V were 0, 5, 6, 6, and 25%, respectively. Long-term permanent deficits from embolization occurred in 8.6% of patients. CONCLUSION: Endovascular treatment carries a procedural risk related to AVM grade and number of branches treated. This risk should be weighed carefully in the context of overall treatment morbidity and mortality.

Adolescent↗
PubMed2006

Low morbidity associated with use of n-butyl cyanoacrylate liquid adhesive for preoperative transarterial embolization of central nervous system tumors.

OBJECTIVE: To determine the safety and efficacy of preoperative embolization of central nervous system tumors with n-butyl cyanoacrylate (NBCA) liquid adhesive. METHODS: Over a 6-year period, 35 consecutive patients (12 women, 23 men; mean age, 42 yr; range, 6 mo-75 yr) with a central nervous system tumor underwent preoperative embolization with NBCA. Tumor type, location, endovascular and surgical treatment, percent of tumor embolization, estimated blood loss, and neurological deficits related to embolization were evaluated retrospectively. RESULTS: One hundred feeding arteries were embolized (mean, 3 vessels/patient). In only one (3%) case was a normal artery inadvertently occluded by the embolization. During the follow-up period, the resulting neurological deficit resolved completely. There were no neurological deficits or inadvertent embolization events in the remaining 34 cases. The mean percent of tumor embolized was 68%, but this did not significantly correlate with operative blood loss (Pearson's correlation coefficient, r = 0.049). CONCLUSION: In experienced hands, central nervous system tumors can be embolized with NBCA liquid adhesive with a high degree of safety and efficacy. We think that adroit embolization technique with NBCA and other embolisates should be part of the contemporary neuroendovascular armamentarium.

Adolescent↗
PubMed2006

An anatomical evaluation of the mini-supraorbital approach and comparison with standard craniotomies.

OBJECTIVE: To compare anatomically the surgical exposure provided by pterional (PT), orbitozygomatic (OZ), and minisupraorbital (SO) craniotomies. METHODS: Seven sides of six fixed cadaver heads injected with silicone were used. The mini-SO craniotomy followed by the PT and OZ approaches were performed sequentially. The bony flaps were attached with miniplates and screws, allowing easy conversion between the approaches. A frameless stereotactic device was used to calculate an area of surgical exposure and the angles of approach for six different anatomic targets. An image guidance system was used to demonstrate the limits of the surgical exposure for each technique. RESULTS: No significant differences were observed in the total area of surgical exposure when comparing the mini-SO (A = 1831.2 +/- 415.3 mm), PT (A = 1860.0 +/- 617.2 mm), and OZ approaches (A = 1843.3 +/- 358.1 mm; P > 0.05). Angular exposure was greater for the OZ and PT approaches than for the mini-SO approach, either in the vertical and horizontal axes, considering all of the six targets studied (P < 0.05). Except for the distal segment of the ipsilateral sylvian fissure, no practical differences in the limits of the exposure were detected. CONCLUSION: The mini-SO approach may offer a similar surgical working area compared with that provided by standard craniotomies and constitutes an excellent alternative to the OZ and PT craniotomies in selected patients. Selection should not be based primarily on the area to be exposed, but rather on the working angles that are anticipated to be required. The key point is to use the most adequate technique for a particular patient, rather than using a one-size-fits-all approach for all patients.

Cadaver↗
PubMed2006

The pterional-transsylvian approach: an analytical study.

OBJECTIVE: Splitting of the sylvian fissure (SF) improves exposure with the pterional (PT) approach. Traditionally, the choice of whether or not to split the SF and how far to open it has depended on the neurosurgeon's experience and preference rather than on quantifiable data. We undertook this study to evaluate the effects of progressive splitting of the SF on surgical exposure with the PT approach. METHODS: A PT craniotomy was performed on nine sides of cadaver heads. Splitting the SF was divided into four steps: 1) dissection of the basal cisterns, 2) dissection of the sphenoidal compartment, 3) dissection of the operculoinsular compartment to the anterior ascendant ramus, and 4) dissection progressing 2.0 cm distal to the anterior ascendant ramus. The degree of the retraction and the relative position of the brain retractors were kept constant. After each step, we used a computerized tracking system to measure the area of surgical exposure of the circle of Willis, the angles of approach to the carotid bifurcation, and the distance between the frontal lobe and skull base. RESULTS: Exposure of the circle of Willis, angles of approach to the carotid bifurcation, and linear distance between the frontal lobe and skull base all increased significantly as splitting of the SF progressed from Steps 1 to 2 and from Steps 2 to 3. There was no significant difference between Steps 3 and 4. CONCLUSION: Exposure of the basal cisterns and circle of Willis by the PT approach is optimized when dissection of the SF reaches the anterior ascendant ramus. Further splitting of the SF provides no additional gain.

Cadaver↗
PubMed2006

Classification and surgical management of spinal arteriovenous lesions: arteriovenous fistulae and arteriovenous malformations.

OBJECTIVE: Preexisting spinal arteriovenous malformation nomenclature can be confusing. The aim of this article is to present a modified classification system for spinal arteriovenous lesions and to discuss its implications for microsurgical strategies. METHODS: Based on the literature review of prior classifications as well as on the experience of the senior author (RFS), the authors delineate an anatomically and pathophysiologically based classification to facilitate the description and treatment of these uncommon entities. RESULTS: Spinal arteriovenous lesions are composed of arteriovenous fistulae and malformations. These lesions are classified as extradural, extradural-intradural, or intradural. Intradural lesions are characterized further as ventral or dorsal fistulae or as intramedullary lesions. Intramedullary lesions are characterized as compact or diffuse. A new category, conus medullaris arteriovenous malformations, is described as a distinct entity. CONCLUSION: This updated classification system eliminates confusion related to older nomenclature and is based on the anatomical and pathophysiological features of these lesions. When treating these lesions, the neurovascular team must collaborate closely with their microsurgical and endovascular colleagues. Finally, treatment should be individualized, depending on lesional angioarchitecture and the patient's clinical status.

Arteriovenous Fistula↗
PubMed2006

Resolution of an infectious pseudoaneurysm in a cervical petrous carotid vein bypass graft after covered stent placement: case report.

OBJECTIVE AND IMPORTANCE: Covered stenting of the carotid artery has been used to treat aneurysms and dissections. We describe a unique case of covered stenting in the setting of an infected psuedoaneurysm in a previously placed cervical-to-petrous vein bypass graft. Operating in an infected field and reopening a surgical wound at the craniocervical junction that had previously been exposed to penetrating trauma created substantial risks to open surgical repair. We therefore chose an endovascular strategy to repair this lesion. CLINICAL PRESENTATION: A 57-year-old diabetic man with a previously placed cervical-to-petrous vein bypass graft presented with chronic otitis media and acute hemorrhage from his right external auditory meatus. Evaluation revealed an infectious pseudoaneurysm of the vein graft at the skull base. TECHNIQUE: The patient was treated with intravenous antibiotics and endovascular placement of an 8-mm x 25-mm polytetrafluoroethylene-covered stent across the pseudoaneurysm. Angiography obtained 8 months later confirmed successful obliteration of the lesion. CONCLUSION: The patient's clinical outcome was excellent. Despite the active infection, covered stenting of the pseudoaneurysm was an effective treatment strategy, obviating the need for open debridement and graft revision.

Aneurysm, False↗
PubMed2006

Quantitative analysis of the working area and angle of attack for the retrosigmoid, combined petrosal, and transcochlear approaches to the petroclival region.

OBJECT: The authors quantitatively assessed the working areas and angles of attack associated with retrosigmoid (RS), combined petrosal (CP), and transcochlear (TC) craniotomies. METHODS: Four silicone-injected cadaveric heads were bilaterally dissected using three approaches progressing from the least to the most extensive. Working areas were determined using the Optotrak 3020 system on the upper and middle thirds of the petroclivus and brainstem. Angles of attack were studied using the Elekta SurgiScope at the Dorello canal and the origin of the anterior inferior cerebellar artery (AICA). The TC approach provided significantly greater (p < 0.001) working areas at the petroclivus (755.6 +/- 130.1 mm2) and brainstem (399.3 +/- 68.2 mm2) than the CP (354.1 +/- 60.3 and 289.7 +/- 69.9 mm2) and RS approaches (292.4 +/- 59.9, 177.2 +/- 54.2 mm2, respectively). The brainstem working area associated with the CP approach was significantly larger (p < 0.001) than that associated with the RS route. There was no difference in the petroclival working area comparing the CP and RS approaches (p = 0.149). The horizontal and vertical angles of attack achieved using the TC approach were wider than those of the CP and RS at the Dorello canal and the origin of the AICA (p < 0.001). CONCLUSIONS: The CP approach offers a more extensive working area than the RS for lesions involving the anterolateral surface of the brainstem, but not for petroclival lesions. The TC approach provides the widest corridor, improving the working area and angle of attack to both areas, but hearing must be sacrificed and the facial nerve is at risk.

Brain Stem↗
PubMed2006

Anatomical and quantitative description of the transcavernous approach to interpeduncular and prepontine cisterns. Technical note.

OBJECT: The management of wide-necked, giant, or unsuccessfully coil-treated basilar apex aneurysms requires a wide exposure, for both working area and linear visualization of the basilar artery (BA). Cranial-based approaches, such as the transcavernous approach, have been proposed to deal with such aneurysms; whether abbreviated forms of this approach might provide similar exposure remains controversial. The authors examine this issue quantitatively. METHODS: Four alcohol-preserved cadaveric heads injected with pigmented silicone were prepared for bilateral dissection. After completing an orbitozygomatic craniotomy, the surgeons worked in a reverse direction, performing the transcavernous approach in five steps: 1) posterior clinoidectomy; 2) cavernous sinus opening; 3) anterior clinoidectomy; 4) cutting of the distal dural ring; and 5) cutting of the proximal dural ring. Performing the complete transcavernous approach significantly increased the working area and linear exposure of the BA compared with abbreviated forms of the approach (p < 0.05). Opening the roof of the cavernous sinus significantly increased the working area compared with posterior clinoidectomy alone (p = 0.014); however, additional gains in exposure required completing the transcavernous approach. Resection of the anterior clinoid process combined with opening of only the distal dural ring did not significantly increase the working area or linear exposure of the BA. CONCLUSIONS: The complete transcavernous approach significantly increases the working area and linear exposure of the BA compared with the more conservative forms of approach.

Basilar Artery↗
PubMed2006

Surgical management of arteriovenous malformations in children.

OBJECT: Children compose 3 to 20% of the patients with arteriovenous malformations (AVMs); however, AVMs are responsible for 30 to 50% of intracranial hemorrhages in children. METHODS: The medical records of 82 children with 84 AVMs treated surgically between 1983 and 2005 were reviewed. Fifty-two patients (63%) presented with hemorrhage, 13.4% presented with seizures, and AVMs in 12% were found incidentally. Patients with brainstem lesions presented at a significantly younger age (p = 0.002) than those harboring lesions in other locations. Frontal lobe lesions were significantly smaller than those in other locations, and thalamic lesions were significantly larger (p = 0.012 and 0.005, respectively). Most patients with Spetzler-Martin Grades I to III lesions underwent craniotomy only. Half of the patients with Grade IV and V lesions underwent embolization, craniotomy, and radiosurgery. The mean follow-up period was 43 months. Postoperatively, the initial obliteration rate was 65%, with a long-term obliteration rate of 90%. The perioperative mortality rate was 3.7%. Altogether, 81% of patients had excellent outcomes, and patients with Grade I lesions had the best outcomes. Of the 52 patients who presented with hemorrhage, 17% had fair or poor outcomes. The recurrence rate was 5.6%. CONCLUSIONS: Children with AVMs may be more prone than adults to present with a hemorrhage and to experience recurrence of the lesion after treatment. The authors favor resection for most AVMs in children and use embolization as a preoperative strategy for Grades II to V lesions treated surgically. Prehemorrhagic Grade IV and V lesions may best be treated conservatively and observed carefully for the development of symptoms. Long-term follow up of all patients is essential.

Cerebral Hemorrhage↗
PubMed2005

Skull base approaches to the basilar artery.

Posterior circulation lesions constitute approximately 10% of all intracranial aneurysms. Their distribution includes the basilar artery (BA) bifurcation, superior cerebellar artery, posterior inferior cerebellar artery, and anterior inferior cerebellar artery. The specific features of a patient's aneurysm and superb anatomical knowledge help the surgeon to choose the most appropriate approach and to tailor it to the patient's situation. The main principle that must be applied is maximization of bone resection. This allows the surgeon to work within a wider corridor, which facilitates the use of surgical instruments and minimizes retraction of the brain. The management of aneurysms within the posterior circulation requires expertise in skull base and vascular surgery. Endovascular treatments have become increasingly important, but in this paper the authors focus on the surgical management of these difficult aneurysms. The paper is divided into three parts: the first section is a brief review of the anatomy of the BA; the second part is a review of the techniques associated with the management of posterior fossa aneurysms; and in the third section the authors describe the different approaches, their nuances and indications based on the location of the aneurysm, and its relationship to the surrounding bone (especially the clivus, dorsum sellae, and the free edge of the petrous apex).

Basilar Artery↗
PubMed2005

Combined skull base approaches to the posterior fossa. Technical note.

Combined approaches to the skull base provide maximal exposure of the complex and eloquent anatomical structures contained within the posterior fossa. Common to these combined exposures are variable degrees of petrous bone removal. Understanding the advantages of each approach is critical when attempting to balance increases in operative exposure against the risk of potential complications. Despite their risks, aggressive combined exposures to the posterior fossa enable the greatest degree of visualization of the anatomy. Consequently, surgeons can approach lesions with maximal margins of safety, which cannot otherwise be realized. To minimize morbidity in all cases, the approach chosen must be applied individually, depending on the lesion and the patient's characteristics.

Cranial Fossa, Posterior↗
PubMed2005

Combined surgical and endovascular treatment of a recurrent A3-A3 junction aneurysm unsuitable for stand-alone clip ligation or coil occlusion. Technical note.

Recurrent aneurysms of the anterior circulation that are distal to the anterior communicating artery (ACoA) but proximal to the callosomarginal-pericallosal bifurcation can pose a treatment challenge. The authors present one such case, in which the patient was treated with pericallosal artery-pericallosal artery (PerA-PerA) side-to-side bypass, followed by endovascular obliteration of the proximal A2 parent vessel. This patient, in whom an ACoA aneurysm had been treated with clip ligation 5 years previously, presented with a new, mid-A2, right-sided aneurysm with the outflow artery arising from the dome of the lesion. The treatment plan included two steps: an interhemispheric transcallosal approach for PerA-PerA side-to-side anastomosis; and endovascular coil embolization of the right A2 branch feeding the aneurysm. Postprocedure angiography demonstrated no ipsilateral aneurysm filling and excellent bilateral distal outflow from the anterior cerebral artery (ACA). The use of PerA-PerA side-to-side bypass for the treatment of an ACA aneurysm, followed by parent vessel occlusion, offers an elegant solution for the treatment of A2 aneurysms that are not amenable to stand-alone clip ligation or coil occlusion. Such combined methods are invaluable in the management of complex cerebral aneurysms.

Cerebral Arteries↗
PubMed2005

Middle cerebral artery stenosis: endovascular and surgical options.

Atherosclerotic middle cerebral artery stenosis is a rare but potentially devastating cause of cerebral ischemia and stroke. While medical management remains the mainstay for stroke prevention, surgical and/or endovascular intervention is indicated in selected patients. This article reviews the role of surgery and endovascular techniques in the treatment of middle cerebral artery stenosis based on its natural history, pathophysiology, and prognosis when treated medically.

Journal Article↗