Minimally invasive superficial temporal artery to middle cerebral artery bypass through an enlarged bur hole: the use of computed tomography angiography neuronavigation in surgical planning

Technical note

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The authors describe their minimally invasive technique for performing a superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, which relies on an enlarged bur hole (2–2.5 cm) rather than the standard craniotomy. They perform this procedure in a minimally invasive fashion, using CT angiography for intraoperative neuronavigation as well as for preoperative identification of the donor and recipient vessels and planning of bur hole location. They present 2 cases in which this procedure was used, including one involving a patient with multivessel occlusive disease and significant cerebrovascular hemodynamic compromise in whom they performed the procedure using only local anesthetic and propofol sedation in order to minimize the risk of hypotension associated with the use of general anesthetic agents. A comprehensive literature search revealed no previously published case of an extracranial–intracranial arterial bypass procedure performed in an awake patient.

The authors have adopted the described minimally invasive method for all STA–MCA bypass procedures. The awake setting, however, is reserved for specific indications, primarily patients with severe moyamoya disease, in whom ventilator-related hypocarbia can result in intraoperative ischemia, or patients with multivessel occlusive disease and significant cerebral hemodynamic compromise, in whom general anesthesia–related hypotension can lead to intraoperative ischemia.

Abbreviations used in this paper: EC = extracranial; IC = intracranial; ICA = internal carotid artery; MCA = middle cerebral artery; STA = superficial temporal artery; TIA = transient ischemic attack.

Abstract

The authors describe their minimally invasive technique for performing a superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, which relies on an enlarged bur hole (2–2.5 cm) rather than the standard craniotomy. They perform this procedure in a minimally invasive fashion, using CT angiography for intraoperative neuronavigation as well as for preoperative identification of the donor and recipient vessels and planning of bur hole location. They present 2 cases in which this procedure was used, including one involving a patient with multivessel occlusive disease and significant cerebrovascular hemodynamic compromise in whom they performed the procedure using only local anesthetic and propofol sedation in order to minimize the risk of hypotension associated with the use of general anesthetic agents. A comprehensive literature search revealed no previously published case of an extracranial–intracranial arterial bypass procedure performed in an awake patient.

The authors have adopted the described minimally invasive method for all STA–MCA bypass procedures. The awake setting, however, is reserved for specific indications, primarily patients with severe moyamoya disease, in whom ventilator-related hypocarbia can result in intraoperative ischemia, or patients with multivessel occlusive disease and significant cerebral hemodynamic compromise, in whom general anesthesia–related hypotension can lead to intraoperative ischemia.

The STA–MCA bypass procedure was the first EC– IC arterial anastomosis; it was initially performed by Yaşargil and Donaghy in 1967.14 Originally used in the treatment of an occluded MCA, its indications encompass states in which moderate flow augmentation is desired. The commonly accepted indications for a lowflow STA–MCA bypass are moyamoya disease, distal MCA aneurysms in which the parent division or branch must be sacrificed, and large-vessel occlusive disease with hemodynamic compromise. The procedure and its technical variations have been described by several senior authors.3,5,9,15,17 Traditionally, the procedure has been based on exposing the distal sylvian fissure for the site of anastomosis by performing a frontotemporal craniotomy.

In this article we describe how, with the aid of a stereotactic neuronavigation system, we minimize the size of the skin incision and the craniotomy so that the procedure can be performed effectively via an enlarged bur hole or small craniotomy (2–2.5 cm). A CT angiogram is used to preoperatively select the donor vessel, the recipient vessel, and the anastomosis site. We have performed STA–MCA bypass using our technique in 5 patients. Two of these cases are described in this paper, including one in which the procedure was performed while the patient was awake (with the aid of local anesthesia and intravenous sedation). All procedures were performed by or under the supervision of the senior author (S.I.A).

Surgical Technique

Preoperative Planning

Using a preoperative CT angiogram that provides clear visualization of the STA, including its frontal and parietal branches, we measure the diameters of these branches and identify the optimal vessel for use as a donor (Fig. 1). This enables us to plan a linear skin incision overlying the chosen donor vessel.

Fig. 1.
Fig. 1.

Image guidance workstation view of the donor vessel (parietal branch of STA [arrow]) in a 3D reconstruction of a CT angiogram.

The bur hole/craniotomy can be planned preoperatively with the help of the stereotactically reconstructed model based on the CT angiogram. The recipient vessel is chosen based on its caliber and superficial location in the sylvian fissure (Fig. 2). The ideal recipient vessel is identified based on the review of the CT angiogram. Using CT angiography–based neuronavigation, the exact location of the bur hole/craniotomy is planned to overlie the selected recipient vessel and to be in the immediate proximity of the selected donor vessel (Fig. 3).

Fig. 2.
Fig. 2.

Image guidance workstation view of the site of the bur hole/craniotomy in coronal, sagittal, axial, and reconstructed skull views. The overlying donor vessel as well as the recipient vessel are visible on both sides of the bur hole location. The blue pointer designates the preselected donor vessel. The red dots designate the preselected location of the bur hole site. (Note the recipient and donor vessels on either side of the red dot/proposed bur hole sites.)

Fig. 3.
Fig. 3.

Image guidance workstation view of the recipient vessel in the sylvian fissure in coronal, sagittal, and axial views and a 3D reconstruction of the CT angiogram. The blue pointer indicates the preselected MCA recipient vessel.

Performing the STA–MCA Anastomosis

The incision is performed under the microscope, and the temporalis muscle is split vertically directly below the selected donor branch of the STA.

A bur hole is made and enlarged to the size of a very small craniotomy (~ 2–2.5 cm) under the microscope (Figs. 4 and 5), and the recipient vessel is exposed in the distal sylvian fissure over a length of 1 cm. A rubber dam is applied and the anastomosis is performed with a 9-0 nylon suture in a running fashion. The back wall is anastomosed first followed by the front wall. Temporary clips are applied on the M4 recipient vessel during the anastomosis. Postoperatively, the patients are followed up with angiography (Fig. 6) or CT angiography (Fig. 7).

Fig. 4.
Fig. 4.

Intraoperative photograph obtained through the microscope while the bur hole/craniotomy was being performed.

Fig. 5.
Fig. 5.

Intraoperative photograph obtained through the microscope demonstrating the maximum diameter of the bur hole/ craniotomy to be ~ 2 cm.

Fig. 6.
Fig. 6.

Anteroposterior and lateral views of the postoperative cerebral angiogram demonstrating the bypass in the form of an STA–MCA (M4 branch) anastomosis.

Fig. 7.
Fig. 7.

A: Coronal view of the postoperative CT angiogram demonstrating maturation of the EC– IC bypass. The recipient vessel (arrow 1) and donor vessel (arrow 2) may be readily appreciated. B: A 3D reconstruction of the postoperative CT angiogram.

Illustrative Cases

Case 1

History and Presentation

A 49-year-old right-handed man presented with a history of progressive righthemisphere TIA-like symptoms since 2002 consisting of numbness of the left side of the face, left arm, and left leg. The patient continued to experience symptoms despite maximal medical therapy, and MR imaging of the brain revealed a small right frontal infarct. Angiography demonstrated occlusion of the right ICA and < 50% stenosis in the left ICA. Medical therapy failed to control the patient's hemodynamic insufficiency symptoms, which continued to progress.

Operation and Follow-Up

The patient underwent an STA–MCA bypass procedure using the technique described above. In follow-up, his symptoms were found to have stabilized. The patient has continued to follow a regimen of antiplatelet therapy.

Case 2

History and Presentation

This 54-year-old man presented with vertebrobasilar insufficiency symptoms and was found to have bilateral occlusions of his vertebral arteries, both of which terminated in the posterior inferior cerebellar arteries. After failure of medical therapy and continued TIAs, the patient underwent repeated neuroimaging, which demonstrated a new occlusion of the right ICA. The patient's cerebral perfusion was at this point solely dependent on his left ICA.

Operation and Follow-Up

In light of the hemodynamic insufficiency in a situation of compromised vascular reserve, we proceeded with our minimally invasive STA–MCA bypass with the patient awake to minimize the risks of general anesthesia–related hypotension. The procedure was performed with the use of a local anesthetic agent as well as an opioid agent, as has been described with respect to glioma surgery.8 Standard head fixation was applied and the stereotactic mode was based on the CT angiogram. The enlarged bur hole/craniotomy was 2.5 cm in diameter. This operation was performed on January 24, 2007. To the best of our knowledge and based upon our review of the literature, this is the first awake craniotomy for an EC–IC bypass procedure.

As of this writing (7 months after the procedure), the patient has not experienced any new TIAs or ischemic episodes since the surgery.

Discussion

In this article, we describe performing STA–MCA bypass using a very limited craniotomy, essentially an enlarged bur hole (~ 2–2.5 cm), with the help of stereotactic CT angiography. We do not advocate using the CT angiogram to replace a preoperative evaluation with a formal cerebral angiogram, but we believe stereotaxy improves the precision and size of the craniotomy and limits the length of the skin incision. Using CT angiogram–based guidance can alter the location of the skin incision, the length of dissection of the STA, and the location and size of the bur hole/craniotomy. The use of stereotaxy for an STA–MCA bypass procedure has previously been described by Kikuta and colleagues,7 who used it in order to target the recipient vessel optimally in an ischemic area of the brain but did not use it to limit the size of the craniotomy. The use of STA–MCA bypass for the treatment of carotid occlusion is currently being studied in the Carotid Occlusion Surgery Study (COSS).4,6 The natural history of patients with hemodynamic compromise is becoming better understood and multiple authors have demonstrated a benefit of the procedure in selected patients.1,2,6,10–13,16,18

Conclusions

The STA–MCA bypass is an established cerebral revascularization procedure that is used in the treatment of selected cases of cerebral aneurysms, moyamoya disease, skull base tumors, and large-vessel occlusive disease. Its role in the treatment of carotid occlusion is under investigation as a stroke prevention measure in patients who have impaired cerebrovascular reserve.

In this technical note we describe a minimally invasive procedure performed via a large bur hole or small craniotomy (2–2.5 cm) and performed under the microscope from beginning to end. The technique is based on the preoperative identification of the point at which the donor and recipient vessels are in closest proximity. It is this preoperative use of CT angiography neuronavigation that allows us to identify the target point precisely and use a minimally invasive procedure.

In our practice, the described minimally invasive STA–MCA bypass technique has replaced the standard STA–MCA bypass technique. The option of performing the procedure while the patient is awake may, in our opinion, be considered for a very narrowly defined set of specific indications. Examples of appropriate patients might include those with severe moyamoya disease in whom ventilator-related hypocarbia can result in intraoperative ischemia or cerebrovascular accident and those with multivessel occlusive disease and significant cerebrovascular hemodynamic compromise in whom hypotension related to general anesthesia can lead to intraoperative ischemia or cerebrovascular accident.

Disclaimer

The authors do not report any conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

References

  • 1

    Abdulrauf SI: Extracranial-to-intracranial bypass using radial artery grafting for complex skull base tumors: technical note. Skull Base 15:2072132005

  • 2

    Baron JCBousser MGRey AGuillard AComar DCastaigne P: Reversal of focal “misery perfusion syndrome” by extra-intracranial arterial bypass in hemodynamic cerebral ischemia. A case study with 15O positron emission tomography. Stroke 12:4544591981

  • 3

    Charbel FTMeglio GAmin-Hanjani S: Superficial temporal artery-to-middle cerebral artery bypass. Neurosurgery 56:1 Suppl1861902005

  • 4

    EC/IC Bypass Study Group: Failure of external carotid-internal carotid arterial bypass to reduce the risk of ischemic stroke. Results of an international randomized trial. The EC/IC Bypass Study Group. N Engl J Med 313:119112001985

  • 5

    Erickson DLSurgical technique for STA-MCA bypass. Erickson DL: Revascularization for the Ischemic Brain Armonk, NYFutura Publishing1988. 103119

  • 6

    Grubb RL JrPowers WJDerdeyn CPAdams HPClarke WR: The Carotid Occlusion Surgery Study. Neurosurg Focus 14:3E92003

  • 7

    Kikuta KITakagi YFushimi YIshizu KOkada THanakawa T: “Target bypass”: a method for preoperative targeting of a recipient artery in superficial temporal arteryto- middle cerebral artery anastomoses. Neurosurgery 59:4 SupplONS320ONS3272006

  • 8

    Meyer FBBates LMGoerss SJFriedman JAWindschitl WIDuffy JR: Awake craniotomy for aggressive resection of primary gliomas located in eloquent brain. Mayo Clin Proc 76:6776872001

  • 9

    Newell DW: Superficial temporal artery to middle cerebral artery bypass. Skull Base 15:1331412005

  • 10

    Nussbaum ESErickson DL: Extracranial-intracranial bypass for ischemic cerebrovascular disease refractory to maximal medical therapy. Neurosurgery 46:37432000

  • 11

    Powers WJMartin WRWHerscovitch PRaichle MEGrubb RL Jr: Extracranial-intracranial bypass surgery: hemodynamic and metabolic effects. Neurology 34:116811741984

  • 12

    Yamauchi HFukuyama HNagahama YNabatame HNakamura KYamamoto Y: Evidence of misery perfusion and risk for recurrent stroke in major cerebral arterial occlusive diseases from PET. J Neurol Neurosurg Psychiatry 61:18251996

  • 13

    Yamauchi HFukuyama HNagahama YNabatame HUeno MNishizawa S: Significance of increased oxygen extraction fraction in five-year prognosis of major cerebral arterial occlusive diseases. J Nucl Med 40:199219981999

  • 14

    Yaşargil MG: Microsurgery Applied to Neurosurgery StuttgartGeorg Thieme1969. 105115

  • 15

    Yaşargil MGKrayenbuhl HAJacobson JH: Microneurosurgical arterial reconstruction. Surgery 67:2212231970

  • 16

    Yonas HSmith HADurham SRPentheny SLJohnson DW: Increased stroke risk predicted by compromised blood flow reactivity. J Neurosurg 79:4834891993

  • 17

    Wanebo JEZabramski JMSpetzler RF: Superficial temporal artery-to-middle cerebral artery bypass grafting for cerebral revascularization. Neurosurgery 55:3953992004

  • 18

    Webster MWMakaroun MSSteed DLSmith HAJohnson DWYonas H: Compromised cerebral blood flow reactivity is a predictor of stroke in patients with symptomatic carotid artery occlusive disease. J Vasc Surg 21:3383451995

Article Information

Address correspondence to: Saleem I. Abdulrauf, M.D., Cerebrovascular and Skull Base Surgery Program, Division of Neurosurgery, Saint Louis University, 3635 Vista Avenue at Grand Boulevard, St. Louis, Missouri 63110-0250. email: abdulrsi@slu.edu.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Image guidance workstation view of the donor vessel (parietal branch of STA [arrow]) in a 3D reconstruction of a CT angiogram.

  • View in gallery

    Image guidance workstation view of the site of the bur hole/craniotomy in coronal, sagittal, axial, and reconstructed skull views. The overlying donor vessel as well as the recipient vessel are visible on both sides of the bur hole location. The blue pointer designates the preselected donor vessel. The red dots designate the preselected location of the bur hole site. (Note the recipient and donor vessels on either side of the red dot/proposed bur hole sites.)

  • View in gallery

    Image guidance workstation view of the recipient vessel in the sylvian fissure in coronal, sagittal, and axial views and a 3D reconstruction of the CT angiogram. The blue pointer indicates the preselected MCA recipient vessel.

  • View in gallery

    Intraoperative photograph obtained through the microscope while the bur hole/craniotomy was being performed.

  • View in gallery

    Intraoperative photograph obtained through the microscope demonstrating the maximum diameter of the bur hole/ craniotomy to be ~ 2 cm.

  • View in gallery

    Anteroposterior and lateral views of the postoperative cerebral angiogram demonstrating the bypass in the form of an STA–MCA (M4 branch) anastomosis.

  • View in gallery

    A: Coronal view of the postoperative CT angiogram demonstrating maturation of the EC– IC bypass. The recipient vessel (arrow 1) and donor vessel (arrow 2) may be readily appreciated. B: A 3D reconstruction of the postoperative CT angiogram.

References

1

Abdulrauf SI: Extracranial-to-intracranial bypass using radial artery grafting for complex skull base tumors: technical note. Skull Base 15:2072132005

2

Baron JCBousser MGRey AGuillard AComar DCastaigne P: Reversal of focal “misery perfusion syndrome” by extra-intracranial arterial bypass in hemodynamic cerebral ischemia. A case study with 15O positron emission tomography. Stroke 12:4544591981

3

Charbel FTMeglio GAmin-Hanjani S: Superficial temporal artery-to-middle cerebral artery bypass. Neurosurgery 56:1 Suppl1861902005

4

EC/IC Bypass Study Group: Failure of external carotid-internal carotid arterial bypass to reduce the risk of ischemic stroke. Results of an international randomized trial. The EC/IC Bypass Study Group. N Engl J Med 313:119112001985

5

Erickson DLSurgical technique for STA-MCA bypass. Erickson DL: Revascularization for the Ischemic Brain Armonk, NYFutura Publishing1988. 103119

6

Grubb RL JrPowers WJDerdeyn CPAdams HPClarke WR: The Carotid Occlusion Surgery Study. Neurosurg Focus 14:3E92003

7

Kikuta KITakagi YFushimi YIshizu KOkada THanakawa T: “Target bypass”: a method for preoperative targeting of a recipient artery in superficial temporal arteryto- middle cerebral artery anastomoses. Neurosurgery 59:4 SupplONS320ONS3272006

8

Meyer FBBates LMGoerss SJFriedman JAWindschitl WIDuffy JR: Awake craniotomy for aggressive resection of primary gliomas located in eloquent brain. Mayo Clin Proc 76:6776872001

9

Newell DW: Superficial temporal artery to middle cerebral artery bypass. Skull Base 15:1331412005

10

Nussbaum ESErickson DL: Extracranial-intracranial bypass for ischemic cerebrovascular disease refractory to maximal medical therapy. Neurosurgery 46:37432000

11

Powers WJMartin WRWHerscovitch PRaichle MEGrubb RL Jr: Extracranial-intracranial bypass surgery: hemodynamic and metabolic effects. Neurology 34:116811741984

12

Yamauchi HFukuyama HNagahama YNabatame HNakamura KYamamoto Y: Evidence of misery perfusion and risk for recurrent stroke in major cerebral arterial occlusive diseases from PET. J Neurol Neurosurg Psychiatry 61:18251996

13

Yamauchi HFukuyama HNagahama YNabatame HUeno MNishizawa S: Significance of increased oxygen extraction fraction in five-year prognosis of major cerebral arterial occlusive diseases. J Nucl Med 40:199219981999

14

Yaşargil MG: Microsurgery Applied to Neurosurgery StuttgartGeorg Thieme1969. 105115

15

Yaşargil MGKrayenbuhl HAJacobson JH: Microneurosurgical arterial reconstruction. Surgery 67:2212231970

16

Yonas HSmith HADurham SRPentheny SLJohnson DW: Increased stroke risk predicted by compromised blood flow reactivity. J Neurosurg 79:4834891993

17

Wanebo JEZabramski JMSpetzler RF: Superficial temporal artery-to-middle cerebral artery bypass grafting for cerebral revascularization. Neurosurgery 55:3953992004

18

Webster MWMakaroun MSSteed DLSmith HAJohnson DWYonas H: Compromised cerebral blood flow reactivity is a predictor of stroke in patients with symptomatic carotid artery occlusive disease. J Vasc Surg 21:3383451995

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