Departments of Neurosurgery (IS, ZHR) and Anesthesiology (MC), Beilinson Medical Center, Petah Tiqva, and University of Tel Aviv Sackler Faculty of Medicine, Tel Aviv, Israel Neurosurgery 31; 154, 1992 ABSTRACT: PATIENTS UNDERGOING CRANIOTOMIES for intracerebral lesions are generally positioned in such a way that the lesion is highest in the field. For midline lesions alongside the falx, patients are commonly positioned on their backs for an anatomically symmetrical approach. We propose positioning the patient in the lateral decubitus position ipsilateral to the lesion to take advantage of gravity by allowing the brain to fall away from the midline, thus obviating the need for retraction. We have used this position in 15 cases of falcine and parafalcine tumors to great advantage, without encountering untoward operative or anesthetic complications. KEY WORDS: Intracerebral lesions; Operative positioning; Surgical technique The standard approach to midline intracranial lesions, as described in textbooks of neurosurgical techniques, consists of a midline craniotomy with the patient in a supine position (1,3-6). For parasagittal meningiomas in the anterior third of the brain, the head is straight and somewhat extended (4); for midthird tumors, it is advised to position patients on their backs, with the head in flexion, or, alternatively, on their sides contralateral to the tumor, with the head slightly elevated (2,5,6). For posterior third parasagittal tumors, a semisitting or prone position is proposed. Clark (1) was one of the first authors to suggest positioning the patient in such a way as to allow the brain to fall away from the falx by gravity, thus minimizing the need for retraction. He used a lateral decubitus position, with the patient lying on the side ipsilateral to the tumor in the paraoccipital, transtentorial approach to the posterior tentorial notch. Anecdotal reference to this technique has appeared in descriptions of the surgical approach to the corpus callosum (2) and other midline operations. DESCRIPTION OF POSITIONING Patients requiring approaches to parasagittal or parafalcine lesions are placed in a lateral decubitus position on the side ipsilateral to the tumor (Fig. 1). A soft sponge is placed beneath the dependent greater trochanter, and a pillow is positioned between the legs, which are mildly flexed. A roll is introduced beneath the dependent axilla to prevent neurovascular

DISCUSSION Positioning of the patient for craniotomy is of paramount importance to avoid intraoperative difficulties and postoperative complications. The factors that must be taken into account include the following: prevention of pressure sores and peripheral neurovascular compromise; height of the head above the heart to reduce venous engorgement, taking into account the possibility of venous air emboli; positioning of the head to allow for direct access to the lesion without having to traverse functional tissue or having vision obstructed by bony prominences of the skull; avoiding compromising the cervical spinal cord by excessive flexion or extension and avoiding jugular outflow compression; and utilization of gravity to aid with brain retraction. Standard operative descriptions of the approach to midline and paramidline lesions do not take into account the last mentioned principle. Supine or prone positions with the head straight in the sagittal plane are advocated to maintain symmetry. Alternatively, the lateral decubitus position on the side contralateral to the tumor has been described. We have employed the lateral decubitus position on the side ipsilateral to the tumor in 15 patients, 13 of whom suffered from parasagittal or falx meningioma, and 2 of whom suffered from intra-axial lesions in the cingulate gyrus. This position allows the brain to fall away from the falx, minimizing the need for brain retraction. The position allows ready access of the operating microscope, with excellent visualization of the abnormality. No untoward side effects from this position were encountered. The positioning of the patient does not require special expertise and does not increase the preparation time required, as compared with the standard techniques. We, therefore, strongly recommend considering this technique as a possible operative approach to midline and paramidline lesions in the cerebral supratentorial compartment. Received, October 18, 1991. Accepted, November 20, 1991. Reprint requests: I. Shevach, M.D., Department of Neurosurgery, Beilinson Medical Center, Petah Tiqva, 49100 Israel. REFERENCES: (1-6)

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AUTHOR(S): Shevach, I., M.D.; Cohen, M., M.B., Ch.B.; Rappaport, Z. H., M.D.

compromise. The operating table is tilted to 10 degrees Trendelenburg, with the head elevated to 25 degrees above the atrium of the heart. Three-pin fixation of the head to the table is utilized, with the head laterally flexed to the dependent shoulder, taking care not to compress the jugular vein. The head is either flexed or extended in the sagittal plane, depending on the anteroposterior position of the tumor. A craniotomy that crosses the midline to expose the sagittal sinus is performed. The dura is opened up to the midline, and arachnoidal adhesions are divided to allow the brain to fall away from the falx (Fig. 2). The need for brain retraction is thereby minimized. Tumor resection proceeds in the standard fashion, utilizing the operating microscope.

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Neurosurgery 1992-98 July 1992, Volume 31, Number 1 154 Patient Positioning for the Operative Approach to Midline Intracerebral Lesions: Technical Note Technical Note

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COMMENT Shevach et al. document the effectiveness of the lateral position for approach to midline lesions of the falcine region. I agree with their findings and further recommend this position for approaching lesions of the lateral and third ventricles. Lateral positioning with the lesion hemisphere dependent is suitable for exposing tumors, arteriovenous malformations, and distal anterior cerebral aneurysms. The position allows the cerebral hemisphere to be dependent, provides a wider corridor of access to deep lesions, and is comfortable for the surgeon and the patient. John M. Tew, Jr. Cincinnati, Ohio

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Clark K: The occipital transtentorial approach to the pineal region, in Schmidek HH, Sweet WH (eds): Operative Neurosurgical Techniques. Orlando, Grune & Statton, Inc., 1988, pp 411-418. Faiks KS, Wyler AR, Herman BP, Somes G: Seizure outcome from anterior and complete corpus callosotomy. J Neurosurg 74:573-578, 1991. Lanman TH, Becker DP: Falcine meningiomas, in Al-Mefty O (ed): Meningiomas. New York, Raven Press, 1991, pp 345-356. Logue V, Symon L: Surgery of meningiomas, in Symon L, Thomas DGT, Clarke K (eds): Rob & Smiths Operative Surgery. Neurosurgery. London, Butterworth, 1989, ed 4, pp 255-266. Maxwell RE, Chou SN: Parasigittal and falx meningiomas, in Schmidek HH, Sweet WH (eds): Operative Neurosurgical Techniques. Orlando, Grune & Stratton, Inc., 1988, pp 563570. Wilkins RH: Parasagittal meningiomas, in AlMefty O (ed): Meningiomas. New York, Raven Press, 1991, pp 329-344.

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Figure 2. Operative view of the falx after resection of an attached meningioma. There is no need for active brain retraction to achieve good exposure of the lesion.

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Figure 1. The patient lies on the side ipsilateral to a falx meningioma. The scalp midline and site of the craniostomy are marked.

Patient positioning for the operative approach to midline intracerebral lesions: technical note.

Patients undergoing craniotomies for intracerebral lesions are generally positioned in such a way that the lesion is highest in the field. For midline...
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