Sinus Pericranii, Petrosquamosal Sinus and Extracranial Sigmoid Sinus

Auris Nasus Larynx 44 (2017) 359–364

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Auris Nasus Larynx

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Sinus pericranii, petrosquamosal sinus and extracranial sigmoid sinus: Anatomical variations to consider during a retroauricular approach Juan Carlos [2_TD$DIFF]*[3_TD$DIFF]Cisneros , Paula Tardim Lopes, Ricardo Ferreira Bento, Robinson Koji Tsuji Otorhinolaryngology Department, Hospital das Clıńicas – University of Saõ Paulo, Saõ Paulo, Brazil

ARTICLE INFO ABSTRACT

Article history: Lateral and sigmoid sinus malformations are uncommon and dangerous anatomical variations that Received 10 April 2016 surgeons may encounter when performing a retroauricular approach. We report three cases of rare Accepted 6 July 2016 temporal bone venous sinus anomalies seen in patients who underwent cochlear implant surgery. Available online 21 July 2016 The first patient had a diagnosis of CHARGE syndrome and presented a bilateral persistent petrosquamosal sinus with sigmoid sinus agenesis, which made mastoidectomy for cochlear Keywords: implantation difficult. The second patient presented an anomalous venous lake in the occipital Encephalic venous drainage pathways Sigmoid sinus region, which communicated the left dural venous sinuses with a conglomerate of pericranial Petrosquamosal sinus vessels in the left nuchal region, also consistent with left sinus pericranii. The third patient Cochlear implantation presented with an extracranial sigmoid sinus that produced a troublesome bleeding immediately Retroauricular approach after the muscular-periosteal flap incision was performed. ß 2016 Elsevier Ireland Ltd. All rights reserved.

1. Introduction communication between the intracranial dural sinuses and the extracranial veins [1–3]. The petrosquamosal sinus is one of The retroauricular surgical approach is the most commonly these rare emissary veins, and in humans it typically regresses practiced approach for exploration of the middle ear. It serves during fetal and early post-natal life. As noted by Mortazavi well to perform all kinds of middle ear related surgeries as well et al. in 2012, it serves as the primary cerebral drainage site in as inner ear surgeries, such as cochlear implantation. In some many lesser primates and quadrupeds, contrary to humans, in cases, rare anatomic variations of the temporal bone related whom the internal jugular veins and vertebral veins represent sinuses, such as the sinus pericranii, might transform this the major outflow pathways. When present, its diameter ranges common surgical pathway into a real life-threatening problem. from 2 to 4 mm, and it originates at the junction of the The term sinus pericranii refers to a cranial venous anomaly, transverse and sigmoid sinuses, coursing laterally above the which presents as a fluctuating, compressible venous scalp superior border of the temporal bone [4]. The petrosquamosal mass that connects directly to the intracranial dural sinuses sinus may be confused with a large mastoid emissary vein, through dilated diploic and emissary veins, which may or may since in many described cases, it presents as an extracranial not become varicous. This anomaly provides a direct, abnormal vein varix in the vicinity of the mastoid region, which may be covered by a thin bone layer or only by subcutaneous tissue. This vascular anomaly demands a correct preoperative * Corresponding author at: Hospital das Clıńicas, University of Saõ Paulo – diagnosis since its damage during surgery may be life Faculty of Medicine, Av. Dr. Eneás de Carvalho Aguiar, 255, 6th Floor, Room 6167, Saõ Paulo 05403 000, Brazil. Phone number: +55(11) 974850206. threatening, leading to troublesome bleeding or even fatal E-mail address: [email protected] (J.C. Cisneros). ischemic consequences, especially because it sometimes http://dx.doi.org/10.1016/j.anl.2016.07.003 0385-8146/ß 2016 Elsevier Ireland Ltd. All rights reserved. 360 J.C. Cisneros et al. / Auris Nasus Larynx 44 (2017) 359–364 represents the major or only drainage route of the transverse the right ear and severe to profound sensorineural hearing loss sinus, which connects the dural sinuses with the external in the left ear were diagnosed, together with growth retardation jugular venous system [5]. and a delay in psychomotor and language development. Since Another venous anomaly of the temporal bone that surgeons childhood, he used a hearing aid in the right ear with good should have in mind is the extratemporal course of the sigmoid benefit, but at 16 years of age, hearing progressively worsened sinus. When encountered, the sinus is anteriorly and laterally bilaterally with a profound hearing loss in the right ear and displaced with no cortical bone cover. This uncommon course anacusis in the left (average hearing threshold of 100 dB in the of the sigmoid sinus may increase the risk of damage and right ear taking into account the 0.5, 1, 2 and 3 kHz troublesome bleeding immediately after a common retro- frequencies). At this point, he became a candidate for cochlear auricular skin incision is performed [6,7]. implantation. It is important to consider that venous malformations of the During physical examination, hypertelorism and a surgically temporal bone are a more common feature when associated with closed cleft palate with an absent uvula were identified; CHARGE syndrome. Besides inner and middle ear anomalies otoscopy revealed a grade 1 bilateral microtia (according to the associated with this syndrome, patients with CHARGE may classification by Altmann et al.) with narrow external auditory present a number of collateral emissary veins in the temporal canals [10]. Tympanic membranes were normal bilaterally. The bone including posterior condylar veins, mastoid emissary veins patient also presented other features typical of CHARGE connecting occipital or post-auricular veins with the sigmoid syndrome, such as genitourinary tract anomalies. Audiological sinus, and the aforementioned petrosquamosal sinus [8]. and imaging findings may be seen in Figs. 1 and 2. Even though most ear surgeons often have temporal bone CT In this case, the association of CHARGE syndrome and images available prior to surgery, these vascular anomalies may sinus pericranii is readily seen [8]. Since cochlear implantation not be easily detected. A thorough analysis of CT scans, as well in the left ear was contraindicated because of vestibulocochlear as contrast-enhanced MRI images, is useful to better diagnose nerve agenesis, only the right ear was implanted. After these anomalies and to avoid surgical complications [9].We considering the vascular malformation seen in the image report three cases of temporal bone venous sinus anomalies studies, a traditional mastoidectomy was avoided and a seen in patients who underwent cochlear implant surgery. suprameatal approach was preferred. A tunnel was drilled just above the Henle’s spine in the posterior–superior region of the 2. Case reports external auditory canal, passing just inferior to the dura of the middle fossa in an anterior–inferior direction, finishing in the 2.1. Case 1 attic. A tympanomeatal flap was elevated to properly see the round window region and insert the electrode array. A A 17-year-old male, with previous diagnosis of CHARGE cochleostomy was performed in the estimated topography of syndrome, was evaluated for cochlear implant surgery. At the the round window, which was absent, and the electrode array age[(Fig._1)TD$IG] of 3 years, moderate to severe sensorineural hearing loss in was completely introduced in the basal turn of the cochlea. The

Fig. 1. Audiometric and MRI ﬁndings prior to cochlear implantation. (A) Audiometric results without hearing aid. The patient showed no speech discrimination. (B) Audiometric results with a well-adapted hearing aid in the right ear. Speech discrimination thresholds in closed and open set are below 50%. (C) Axial MRI image of the right and left internal auditory canals showing a cochlear nerve in the right side (arrowhead) and absence of the cochlear nerve in the left, which correlates with auditory ﬁndings. The $ shows the hypoplasic cystic labyrinth bilaterally. dB = decibel, Hz = hertz. [(Fig._2)TD$IG] J.C. Cisneros et al. / Auris Nasus Larynx 44 (2017) 359–364 361

Fig. 2. Temporal bone CT scan images of case 1. The images are presented comparing the osseous and soft tissue, and contrast-enhanced windows at various levelsto show the complete path of the sinus pericranii (arrowheads), from the transverse sinus (A, B) coursing through the mastoid to its drainage in a dilated external jugular vein ([4_TD$DIFF]F–H). Notice the great number of emissary veins coursing through the mastoid, that connect the transverse sinus to the occipital region vessels easily seen in the osseous windows (A–C). Middle and internal ear anatomy anomalies such as ossicular chain malformation (D, E), lateral and superior semicircular canal agenesis with vestibular hypoplasia (C–E), and an enlarged vestibular aqueduct ($ in D and E) as well as apical cochlear[1_TD$DIFF]hypoplasia (D, E) may be identified. The sigmoid sinus is absent as well as the jugular bulb. tympanomeatal flap was replaced and the receiver-stimulator During cochlear implant evaluation, ear CT scans and MR was positioned in a niche previously drilled in the squamous imaging demonstrated an abnormally high jugular bulb on the portion of the temporal bone, in a more vertical fashion than left side and an abnormal venous lake in the occipital region, usual to avoid the sinus pericranii. After 3 months of activation, which communicated the left dural intracranial venous sinuses the cochlear implant allowed an improvement in average pure with a conglomerate of pericranial vessels in the nuchal region tone thresholds to 42 dB, with field discrimination in closed set deep to the muscle and adipose planes, consistent with sinus of 100% and open set of 55%. The postoperative temporal bone pericranii. Temporal bone CT scans and MRI images may be CT scans with the cochlear implant in place are presented in seen in Fig. 4. Fig. 3. During audiometric evaluation, both sides presented a restricted access to speech perception, and despite the longer 2.2. Case 2 auditory deprivation time for the right ear, this ear was selected for cochlear implantation to avoid any of the vascular A 66-year-old male presented with a progressive bilateral abnormalities in the left side. A good functional result was hearing loss that started at the age of 2. No direct causes were obtained after cochlear implant activation. identified and there was no related family history of hearing loss. He started using a hearing aid on the right ear when he was 2.3. Case 3 26 years old and on the left at 55 years of age when he became a candidate for cochlear implantation. Throughout his life, he A 4-year-old male presented with a history of bilateral developed excellent lip-reading skills and he underwent speech profound hearing loss secondary to adverse factors at birth therapy once a week. and aminoglycoside use. Brain stem evoked response [(Fig._3)TD$IG] 362 J.C. Cisneros et al. / Auris Nasus Larynx 44 (2017) 359–364

Fig. 3. Postoperative temporal bone CT images and cranial general scan. The axial (A–C) and coronal (D, E) images demonstrate that electrodes are properly inserted in the cochlea through a suprameatal approach. The general scan (F) shows the position selected for the receptor-stimulator to avoid the sinus pericranii. audiometry showed absent responses bilaterally. The patient cranial nerves bilaterally and the report of a CT scan presented with an MRI and the radiologist’s report of a CT suggested a normal anatomy of the external, middle and scan performed in an outside setting. The MRI showed inner ear bilaterally. At the time of surgery, only the MRI normal inner ear anatomy with present seventh and eighth images were available. [(Fig._4)TD$IG]

Fig. 4. Preoperative temporal bone coronal CT scans and MRI sagittal images. (A–C) Preoperative temporal bone CT images showing a high jugular bulb and a well- pneumatized mastoid. (D, E) T1-weighted sagittal MRI images after contrast that demonstrate an anomalous venous lake in the occipital region, which communicates the left dural venous sinuses with a conglomerate of pericranial vessels in the nuchal region (arrows) deep to the muscle and adipose planes, consistent with sinus pericranii. [(Fig._5)TD$IG] J.C. Cisneros et al. / Auris Nasus Larynx 44 (2017) 359–364 363

Fig. 5. Preoperative temporal bone CT scans from case 3. Preoperative temporal bone CT images showing the path of the sigmoid sinus (arrowheads). A–C are coronal images that show a high sigmoid sinus in a well-pneumatized mastoid. D–F are axial images of the same case. Notice the areas of bone dehiscence (arrows) in C and F where the sigmoid is superﬁcial. All other external, middle and inner ear structures are normal.

During surgery, anesthetic infiltration was performed in the infiltration, the skin incision or at the beginning of the mastoid retroauricular region in a normal fashion. A retroauricular C- cortical bone drilling. shaped skin incision was performed at a distance of 0.5 cm The first author to report the presence of a persistent from the conchal cartilage and the temporalis fascia plane was petrosquamosal sinus was Moreau in 1929 [11] and its first identified. A muscular-periosteal anteriorly based flap was radiological description was given by Marsot-Dupuch in 2001 performed in a regular fashion with a Bovie electrocautery, and [12]. In 2005, Koesling et al. retrospectively analyzed 223 high- immediately after incising the muscle, a profuse and resolution CT scans of the temporal bone to identify the troublesome bleeding started. The mastoid cortex was properly occurrence of vascular anomalies. In this study, they noted a exposed while compression was performed to stop the bleeding. persistent petrosquamosal sinus in 1% of the analyzed temporal Bipolar cautery and bone wax were unsuccessful to control the bones and an anterior and dehiscent sigmoid sinus in less than bleeding. After an initial drilling of the mastoid cortex, it was 1% [13]. Since apparently 1 in every 100 temporal bones may identified that bleeding came from a laterally and anteriorly present with a patent petrosquamosal sinus or some form of displaced sigmoid sinus, which had no cortical bone cover sinus pericranii, ear surgeons should always perform a (extracranial sigmoid sinus). Bleeding was controlled by thorough revision of imaging studies with these vascular carefully placing layers of oxidized regenerated cellulose anomalies in mind. Attention should be paid to the fact that (Surgicel1, Johnson & Johnson Wound Management, a even though an extracranial sigmoid sinus is even more rare, in Division of Ethicon Inc., Somerville, NJ) on top of the our series it was the most troublesome malformation exposed sinus without introducing them in the sinus lumen. encountered, causing a profuse bleeding in a 4-year-old patient. After achieving bleeding control, a simple mastoidectomy was Every ear surgeon must know how to deal with complica- performed in the regular fashion. A posterior tympanotomy was tions, such as the bleeding from emissary veins, that may result done and the cochlear implant electrode array was inserted in the formation of a postoperative epidural hematoma through the round window membrane without other complica- [14,15]. Bone wax is a good alternative to stop the bleeding tions. No retroauricular hematoma or bleeding was observed from a normal mastoid emissary vein or from an exposed area during the postoperatory period. The preoperative CT scan of dura, but it is not a good option when dealing with bleeding images were retrieved after surgery to evaluate if complications from large emissaries such as a persistent petrosquamosal sinus. could have been avoided; they are shown in Fig. 5. Bone wax is also not recommended to stop bleeding from a sigmoid sinus tear. It is important to note that bone wax applied 3. Discussion into bleeding emissary foramina has been known to enter the deeply placed venous sinuses and results in extensive A great number of ear surgeries starts with a retroauricular thrombosis. The use of a muscle plug that does not obstruct incision and a simple mastoidectomy. If a sinus pericranii,a the whole lumen of the sinus has also been recommended. petrosquamosal sinus or an extratemporal sigmoid sinus are Monopolar cautery coagulation of these venous channels may present, they may be damaged during the most common initial result in dural venous sinus thrombosis and consequent cerebral steps of surgery, such as subcutaneous retroauricular anesthetic infarction. If coagulation is to be done in a small sinus tear or an 364 J.C. Cisneros et al. / Auris Nasus Larynx 44 (2017) 359–364 emissary vein, low current bipolar coagulation is recommended [3] Bouali S, Maamri K, Abderrahmen K, Asma B, Boubaker A, Hafedh J. [16,17]. It is the authors’ opinion that placing a sufficient Clinical and imaging findings in a rare case of sinus pericranii. 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