Reconstruction of the vein of Labbé by using a short saphenous vein bypass graft

Transcription

1 J Neurosurg 89: , 1998 Reconstruction of the vein of Labbé by using a short saphenous vein bypass graft Technical note AKIO MORITA, M.D., AND LALIGAM N. SEKHAR, M.D. Department of Neurosurgery, The George Washington University Medical Center, Washington, D.C. Protection of the vein of Labbé is a significant concern during surgery that involves retraction of the temporal lobe. A cranial base surgical approach, especially one via the presigmoid petrosal route, carries considerable risk to this venous complex. A case is presented in which a large dominant vein of Labbé was injured during resection of a petroclival meningioma. This vein drained all the sylvian venous circulation as well as the lateral temporal surface; no connection to another venous system was noted. The vein was successfully reconstructed using a short saphenous vein bypass graft. Significant complications could have occurred without this reconstruction. The technique and benefits of this type of reconstruction are discussed. KEY WORDS petrosal approach petroclival meningioma reconstructive surgery saphenous vein graft vein of Labbé P RESERVATION of the vein of Labbé is essential during surgery that involves temporal lobe retraction. 11 Injury to this vein may produce serious consequences, such as temporal lobe ischemia, hemorrhagic infarction, and/or significant edema. During cranial base surgery, especially when a presigmoid petrosal approach is used, this vein is vulnerable to injury because of temporal lobe retraction. 1 Although several ways to avoid damage to this vein have been discussed, 12,19 no method has been reported to repair or reconstruct it after it has been injured. In this paper, we report on a case in which an injured vein of Labbé was successfully reconstructed using a short saphenous vein graft bypass. We describe our technique and discuss the indications and benefits of such a procedure. Illustrative Case History and Neuroimaging Findings. This 58-year-old woman presented with a 2-year history of trigeminal neuralgia. Magnetic resonance (MR) imaging revealed a cm mass in the right petroclival region (Fig. 1 left). An angiogram demonstrated a tumor stain from the meningohypophyseal trunk. Based on these radiological findings, this tumor was diagnosed as a petroclival meningioma. The venous phase of the angiogram revealed a J. Neurosurg. / Volume 89 / October, 1998 large vein of Labbé on the right side that provided drainage for the sylvian venous system and lateral temporal surface (Fig. 1 right). There was no connection to the vein of Trolard or drainage to the sphenopetrosal sinuses. The tumor was embolized before surgery and removed via a right-sided retrolabyrinthine presigmoid approach. During surgery, the large temporal vein was found to drain into a tentorial venous sinus anterior to the sigmoid sinus and was injured during division of the tentorium. After tumor resection was completed, the right temporal lobe was noted to be swollen, and reconstruction of the temporal vein was performed. Operative Technique. A short segment of the saphenous vein was harvested from the pretibial area and was flushed and expanded using heparinized saline. A small amount of fat was left around the venous graft to facilitate dural closure. The injured vein of Labbé was dissected distally and a segment was isolated for anastomosis. The vein was engorged and, by releasing a temporary clip, a very brisk venous flow was produced. The end of this vein and the distal end of the saphenous vein graft were subjected to oblique venotomy with a fish-mouth incision. Although the caliber of these two vessels was close, the temporal vein was thinner than the venous graft. Therefore, meticulous attention was required during anastomosis so as not 671

2 A. Morita and L. N. Sekhar FIG. 1. Left: Magnetic resonance image demonstrating a medium-sized petroclival meningioma. Right: Venous phase of the right carotid artery angiogram, revealing a large single vein draining into the sylvian venous system and the temporal surface. to put stress on the wall of the temporal vein. Anastomosis was achieved using No. 7-0 Prolene (Ethicon, Inc., Somerville, NJ) sutures in a continuous fashion with a single suture on one side and two on the other (Fig. 2A). After the veins had been anastomosed, a wide patency was confirmed by flushing the vein with heparinized saline. The saphenous vein was then cut to a length of 3 cm and implanted into the sigmoid sinus without interrupting the flow of the sigmoid sinus. An oblique venotomy was made with a fish-mouth incision in the proximal end of the vein graft. The medial side of this vein was sutured to the lateral wall of the sigmoid sinus by using a continuous suture. Following this, four interrupted sutures were placed laterally between the wall of the sigmoid sinus and the lateral wall of the saphenous vein graft (Fig. 2B). With gentle compression of the sigmoid sinus, made using a cotton pad and suction, a venotomy was made into the sigmoid sinus to open the ostium, where brisk bleeding was encountered (Fig. 2C). The sutures were tied and several more interrupted stitches were placed. The anastomotic site was flushed with heparinized saline and the temporary clip that had been placed on the temporal vein was removed. Two additional sutures were placed to prevent further bleeding. The patency of the vein graft was confirmed (Fig. 3) using a Matas test. It was also apparent that the venous congestion in the temporal lobe lessened after reconstruction. Dural closure was accomplished using a pericranial graft, and the dura was sutured to the fat around the vein graft to prevent cerebrospinal fluid leakage. Postoperative Course. The patient recovered from surgery without major neurological complications, except for a right-sided facial hypesthesia and an abducent nerve paralysis. Postoperative computerized tomography (CT) scans did not show any temporal lobe swelling (Fig. 4A and B). Postoperatively, a venogram obtained using an MR technique (Fig. 4C) and contrast-enhanced threedimensional CT scans (Fig. 4D) showed a patent venous bypass. These CT scans are processed by a surfacerendered imaging technique after volume acquisition in which a high-speed helical CT scanner is used (GE High Speed Advantage; GE Medical Systems, Milwaukee, WI). FIG. 2. Schematic drawings. A: Anastomosis of the cortical vein and the saphenous vein graft. Note the difference in the thickness of the veins. A large venotomy was made to maintain the width of the anastomotic ostium. B: Partial anastomosis of the vein graft to the sigmoid sinus before the venotomy to the sinus was made. No temporary occlusion was used during anastomosis. C: The anastomosis has been completed. Vessels are opacified by power injection of 150 ml of 320 Optiray (Mallinckrodt Medical Inc., St. Louis, MO) injected over 50 seconds. At 6-month follow-up review, the patient s facial hypesthesia had greatly improved and the abducens palsy had resolved. Although MR venography was not performed, MR examination did not demonstrate any evidence of venous insufficiency or residual tumor. Discussion In this report we describe a technique by which a major cortical vein can be reconstructed using a saphenous vein graft. This method is very useful in preventing major venous complications in intracranial surgery. The significance of intracranial venous interruption has become well known. Venous sinus occlusion can induce a severe increase in intracranial pressure and diffuse cerebral swelling and can cause cerebral ischemia and/or hemorrhagic infarction, especially when the occlusion extends into the cortical veins. 4 However, because of the anato-mical and physiological variability among individual patients, it has been difficult to establish guidelines to determine when and which veins can be sacrificed safely. 672 J. Neurosurg. / Volume 89 / October, 1998

3 Reconstruction of the vein of Labbé FIG. 3. Intraoperative photograph showing reconstruction of the vein of Labbé. SVG = saphenous vein graft. Vein of Labbé was the original designation of the vein that connected the transverse sinus to other supratentorial venous systems, such as the sylvian veins or the vein of Trolard. 10 Currently, this term is used to indicate the largest vein in the lateral aspect of the temporal lobe. 8,13 Although some investigators 9 classify the lateral temporal veins into two types, the anterolateral temporal vein and the posterolateral temporal vein (vein of Labbé), it is often difficult to categorize the lateral temporal veins. The vein of Labbé has been considered an unforgiving vein that cannot be sacrificed without significant consequences. 1,8,11 However, Guppy, et al., 5 recently analyzed the posterior temporal venous circulation and showed that the vein of Labbé represents only a minor portion of the dominant venous drainage system from the posterior temporal lobe. These authors, as well as Krisht, et al., 9 have pointed out that if there are other dominant veins in the temporal lobe (medial or anterior veins), these should be handled more carefully than the vein of Labbé. Variable anatomical configurations, such as collateral circulation and flow dominance, make it extremely difficult to determine which vein can be safely sacrificed. At this time, an angiogram with a detailed venous study is the most practical method to determine the risks involved. Venous size, number of veins in the lateral and medial temporal surface, and connection to other drainage systems should be assessed. Location of entry to the sinuses and the route of the veins are other important factors in planning surgery. When the so-called vein of Labbé is large and the only vein in the lateral temporal lobe surface without sufficient connections with other venous systems, the risk of producing serious sequelae as a result of injuring this vessel is very high. Another indication in predicting postoperative complications is the observation of venous engorgement during surgery. If cerebral venous engorgement and/or cerebral swelling develop after temporary occlusion or sacrifice of the vein, this suggests a high likelihood of postoperative complications. The anesthetized brain, however, may not show engorgement, even with an impending venous infarction. Preoperative venous assessment is currently the most reliable way to predict the consequence of venous injury. Although a method to measure intraluminal FIG. 4. A and B: Postoperative CT scans demonstrating no hematoma or edema in the right temporal lobe. Magnetic resonance venography (C) and a contrast-enhanced three-dimensional CT scan (D) obtained using a high-speed spiral CT scan that demonstrate a patent venous bypass (arrows). pressure in the dural venous sinus has been described, 15,18 this method is not practical to indicate a safe range of occlusion pressure for the cortical veins. In the presigmoid petrosal approach, if the vein of Labbé runs to the inferior aspect of the temporal lobe or joins into or close to the superior petrosal sinus, the risk of stretching or causing direct injury to this vein is high. The J. Neurosurg. / Volume 89 / October,

4 A. Morita and L. N. Sekhar length of the vein that can be dissected from the tentorium varies, and it is often difficult to determine whether the vein under the temporal lobe is in the tentorium or on the surface of the temporal lobe. 8,13 In our current case, the vein drained into a tentorial venous sinus approximately 2 cm before joining the superior petrosal sinus. It is also important to realize that retraction of the temporal lobe significantly influences venous drainage. 3,11 Various techniques have been described to protect the cerebral cortical veins during surgery 12,19 and to reconstruct the large venous sinuses in case of injury or anticipated surgical sacrifice during removal of tumors. 2,6,15 17 Sugita, et al., 19 described the technique used to dissect the distal portion of the venous confluence to the sinus, even relaxing the vein by removing the small portion of the cortex adherent to it. To avoid injury to the temporal vein during a petrosal approach, the technique of cutting the tentorium anterior to the confluence of vein to the tentorial venous lake has been reported. 5,12 However, no techniques have been reported to reconstruct the cortical vein once injury occurs. Direct anastomosis or suturing were not successful in the majority of cases. Also, in cases in which a high-risk venous configuration has been encountered, an alternate surgical approach has been used with suboptimal tumor exposure. The technique we describe here can be safely and efficiently applied to other cortical venous reconstructions. A small-caliber saphenous vein graft is easily harvested from the patient s lower pretibial area. Anastomosis to the cortical vein can be achieved using a continuous suturing technique. Temporary occlusion of the dominant venous sinus may induce immediate cerebral swelling or hemorrhage and thus should be avoided. We partially anastomosed the distal bypass end to the wall of the sinus before opening the sinus. Venous bleeding from the sinus can be easily controlled by putting pressure on the graft, and subsequent stitching can be performed. This reconstruction technique can be strategically used in some of the surgical approaches that put a dominant cortical venous complex at risk. For example, this reconstructive technique might be beneficial to widen the surgical field and to lower the risk to the venous complex, a particularly useful technique in patients who require a temporal lobe retraction to approach a medial temporal or midbrain lesion on the side of the dominant vein of Labbé or in patients with an interhemispheric lesion that requires an approach close to the large parasagittal bridging veins. Technical problems with a venous anastomosis include a high rate of postoperative occlusion and technical difficulties involving the thin wall of the cortical veins. To avoid an acute occlusion, the recipient vein as well as the graft should be manipulated carefully, and a wide anastomotic diameter should be maintained using a relatively large oblique venotomy. Sakai, et al., 14 reported that the patency rate after venous reconstruction increases if the venous pressure gradient is high. Hence, sinus pressure should be kept low in the postoperative period by elevating the head. Although achievement of long-term patency with this technique has not been confirmed, we believe that this method will reduce the risk of acute venous occlusion. Even if the venous bypass should become occluded in a delayed fashion, collateral circulation often develops with gradual venous occlusion. The application of dye to the ostium of anastomotic vessels can improve visualization of the thin venous wall. 7 The difference in wall thickness between the cortical vein and the saphenous vein graft can induce a tear in the vein if needles or sutures are pulled away from the venous wall. The venous wall should be pushed with a counteracting force to the needle while producing each stitch. Meticulous surgical techniques for the anastomosis of various vessels can only be acquired through significant experimental and clinical experience. Conclusions We have reported a case in which the vein of Labbé was reconstructed to avoid serious sequelae. The method used here has not been previously reported in medical texts. This is a very important technique that should be considered when an injury to a dominant cortical vein has occurred. It may also be used preventively to achieve an optimal surgical approach when damage to a large cortical vein is an anticipated result of brain retraction while using a particular approach. Acknowledgments The authors express their gratitude to Jennifer Pryll for her illustrative and photographic assistance and to Joseph Reister for editing and preparing the manuscript. References 1. Al-Mefty O, Fox JL, Smith RR: Petrosal approach for petroclival meningiomas. Neurosurgery 22: , Donaghy RMP, Wallman LJ, Flanagan MJ, et al: Sagittal sinus repair. Technical note. J Neurosurg 38: , Fries G, Perneczky A: Intraoperative obliteration of cerebral veins with special reference to the vein of Labbé, in Hakuba A (ed): Surgery of the Intracranial Venous System. Tokyo: Springer-Verlag, 1996, pp Fries G, Wallenfang T, Hennen J, et al: Occlusion of the pig superior sagittal sinus, bridging and cortical veins: multistep evolution of sinus-vein thrombosis. J Neurosurg 77: , Guppy KH, Origitano TC, Reichman OH, et al: Venous drainage of the inferolateral temporal lobe in relationship to transtemporal/transtentorial approaches to the cranial base. Neurosurgery 41: , Hakuba A, Huh CW, Tsujisawa S, et al: Total removal of a parasagittal meningioma of the posterior third of the sagittal sinus and its repair by autologenous vein graft. Case report. J Neurosurg 51: , Kamiyama H, Takahashi A, Houkin K, et al: Visualization of the ostium of an arteriotomy in bypass surgery. Neurosurgery 33: , Koperna H: Tschabitscher M, Knosp E: The termination of the vein of Labbé and its microsurgical significance. Acta Neurochir 118: , Krisht AF, Barrow DL, Al-Mefty O, et al: Venous anatomy of the vein of Labbé complex, in Hakuba A (ed): Surgery of the Intracranial Venous System. Tokyo: Springer-Verlag, 1996, pp Labbé C: Note sur la circulation veineuse du cerveau et sur le mode de developpement des corpusules de Pacchioni. Arch Physiol Norm Pathol 11: , Malis LI: Venous involvement in tumor resection, in Hakuba A (ed): Surgery of the Intracranial Venous System. Tokyo: Springer-Verlag, 1996, pp J. Neurosurg. / Volume 89 / October, 1998

5 Reconstruction of the vein of Labbé 12. Ohnishi H, Nakase H, Watanabe Y, et al: Preservation of the vein of Labbé in the approach of skull-base lesion, in Hakuba A (ed): Surgery of the Intracranial Venous System. Tokyo: Springer-Verlag, 1996, pp Oka K, Rhoton AL Jr, Barry M, et al: Microsurgical anatomy of superficial veins of the cerebrum. Neurosurgery 17: , Sakai T, Morimoto T, Nakase H, et al: Revascularization of the dural sinus occluded by a meningioma using the saphenous vein graft, in Hakuba A (ed): Surgery of the Intracranial Venous System. Tokyo: Springer-Verlag, 1996, pp Schmid-Elsaesser R, Steiger HJ, Yousry T, et al: Radical resection of meningiomas and arteriovenous fistulas involving critical dural sinus segments: experience with intraoperative sinus pressure monitoring and elective sinus reconstruction in 10 patients. Neurosurgery 41: , Sekhar LN, Tzortzidis FN, Bejjani GK, et al: Saphenous vein graft bypass of the sigmoid sinus and jugular bulb during the removal of glomus jugulare tumors. Report of two cases. J Neurosurg 86: , Sindou M, Mercier P, Bokor J, et al: Bilateral thrombosis of the transverse sinuses: microsurgical revascularization with venous bypass. Surg Neurol 13: , Spetzler RF, Daspit CP, Pappas CTE: The combined supra- and infratentorial approach for lesions of the petrous and clival regions: experience with 46 cases. J Neurosurg 76: , Sugita K, Kobayashi S, Yokoo A: Preservation of large bridging veins during brain retraction. Technical note. J Neurosurg 57: , 1982 Manuscript received February 18, Accepted in final form May 29, Address reprint requests to: Laligam N. Sekhar, M.D., Department of Neurological Surgery, The George Washington University Medical Center, 2150 Pennsylvania Avenue NW, Suite 7-420, Washington, D.C J. Neurosurg. / Volume 89 / October,