Copyright © 2016 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited. forms the posterior roof and the upper part of the lateral wall of the cavernous sinu. 4 Importantly, the third nerve passes through the anterior and posterior petroclinoidal folds, and the location of the third nerve piercing the dura of the cavernous sinus is between 2 and 7 mm (average 5 mm) posterior to the initial supraclinoid segment of the carotid artery, and 7.2  1.8 mm from the ACP. 4,7 Thus, to avoid injury of the third nerve, the fenestration must be created medially and anteriorly to the entrance of the third nerve into the roof of the cavernous sinus. For potential clipping of the aneurismal neck in the event of intraoperative rupture, the APF fenestration should be performed prior to final dissection of the aneurysm neck and dome. 3 Initially, the cisternal part of the third nerve must be visualized to recognize its trajectory toward the cavernous sinus inferior and medial to the APF. Subsequently, a vertical, linear 3 to 4 mm cut is performed with an 11 blade through the APF, anteriorly to the third nerve and posterolaterally to the ACP. The linear fenestration of the APF is then widened using bipolar coagulation to create a wedge-shaped fenestration corridor. This corridor allows for the placement of the proximal clip blade as well as visualization of the proximal aneurismal neck. Care must be taken when the fundus of the aneurysm adheres closely to the APF, as opening of the fold may disturb an unstable and potentially thin part of the aneurysmal dome. Minor venous bleeding from the fenestration may be encoun- tered due to opening of the cavernous sinus roof or part of the intercavernous sinus, and is easily controlled by bipolar coagulation or with hemostatic materials. On the other side, AC is a well-known technique in the microsurgical clipping of the paraclinoid ICA aneurysms, because it facilitates enhanced visualization of structures in and around the optic nerve and proximal ICA. 8 However, AC may cause various complications, including heating injury to the optic, oculomotor nerve, premature aneurysm rupture, cavernous sinus bleeding, and CSF leakage. 8,9 This technique is also occasionally time- consuming and not absolutely necessary for PCoA aneurysm surgery. 9 Comparing to AC, APF fenestration has some obvious advan- tages. 5 First, APF fenestration is simple and timesaving. Because the APF is a ligamentous structure, it could be retracted and widened very quickly by heating with the bipolar coagulator. Second, APF fenestration decreases the risk of neurovascular damage and postoperative CSF leakage, which were expected during the AC. Third, it provides easy proximal ICA control, relatively easy aneurysm neck dissection, and complete aneurysm neck clipping. However, 1 drawback of APF fenestration is that the accurate spatial relation between the aneurysm and APF could only be visualized intraoperatively, while the relation between the aneurysm and ACP could be identified from the preoperative angiography. At last, we should stress that APF fenestration is not an alternative to AC in patients with an enlarged clinoid process that obscures both the proximal aneurismal neck and compromises proximal control. 3,5 In conclusion, during the microsurgical clipping of PCoA aneurysms projecting posterolaterally, it could pose a technique challenge due to the obscuration of the aneurismal neck and fundus by the APF. Here, we describe a technique utilizing the APF fenestration to facilitate visualization and surgical clipping of these aneurysms, and we suggest it to be a simple and useful maneuver in selected PCoA aneurysms surgery. REFERENCES 1. Jeong HW, Seo JH, Kim ST, et al. Clinical practice guideline for the management of intracranial aneurysms. Neurointervention 2014;9:63–71 2. Sanai N, Caldwell N, Englot DJ, et al. Advanced technical skills are required for microsurgical clipping of posterior communicating artery aneurysms in the endovascular era. Neurosurgery 2012;71: 285–294 3. Nossek E, Setton A, Dehdashti AR, et al. Anterior petroclinoid fold fenestration: an adjunct to clipping of postero-laterally projecting posterior communicating aneurysms. Neurosurg Rev 2014;37:637–641 4. Rhoton AL Jr. The cavernous sinus, the cavernous venous plexus, and the carotid collar. Neurosurgery 2002;51 (suppl):S375–S410 5. Kim JH, Kim JM, Cheong JH, et al. Simple anterior petroclinoid fold resection in the treatment of low-lying internal carotid-posterior communicating artery aneurysms. Surg Neurol 2009;72:142–145 6. Beretta F. The paraclinoid aneurysms and the distal dural ring: a new classification. J Neurosurg Sci 2004;48:161–175 7. Rhoton AL Jr. Aneurysms. Neurosurgery 2002;51 (suppl):S121–S158 8. Chi JH, Sughrue M, Kunwar S, et al. The ‘‘yo-yo’’ technique to prevent cerebrospinal fluid rhinorrhea after anterior clinoidectomy for proximal internal carotid artery aneurysms. Neurosurgery 2006;59 (suppl 1): ONS101–ONS107 9. Noguchi A, Balasingam V, Shiokawa Y, et al. Extradural anterior clinoidectomy. Technical note. J Neurosurg 2005;102:945–950 Healing Effects of Platelet-Rich Plasma on Peripheral Nerve Injuries Farshid Bastami, DDS,  Peyman Vares, DDS,  and Arash Khojasteh, DDS, MS y Abstract: Regeneration of peripheral nerve injuries (PNIs) has been a major challenging issue in regenerative medicine and tissue engineering. Inferior alveolar nerve and lingual nerve injuries are the major difficulties and complications of oral surgeries following dental implant placement, etc. The aim of this study was to system- atically review the effects of platelet-rich plasma (PRP) on the regeneration of PNIs. Medline NCBI databases were searched for related articles up to and including May 2016. Being published in English papers, use of PRP in peripheral nerve regeneration, in vivo studies, and having histological evaluations was the inclusion criteria. Seventeen papers were selected according to the inclusion and exclusion criteria, and categorized regarding PNIs types includ- ing cut or crushed injuries. The effects of using PRP only or in combination with cells on the functional recovery and histological assessments are discussed and compared with the other treatments such as autologous nerve graft, acellular nerve allograft, and From the  Research Institute of Dental Sciences, School of Dentistry, Shahid Beheshti University of Medical Sciences; and y Department of Tissue Engineering, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Received July 5, 2016. Accepted for publication August 12, 2016. Address correspondence and reprint requests to Dr Farshid Bastami, DDS, Postdoctoral Research Fellow, Research Institute of Dental Sciences, School of Dentistry, Shahid Beheshti University of Medical Sciences, PO 19839, Daneshjou Boulevard, Evin, Tehran, Iran; E-mail: farshidbst@gmail.com The authors report no conflicts of interest. Copyright # 2016 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000003198 The Journal of Craniofacial Surgery  Volume 28, Number 1, January 2017 Brief Clinical Studies # 2017 Mutaz B. Habal, MD e49