Extradural Temporopolar Approach Research Articles

Limited Indications for Clipping Surgery of Paraclinoid Aneurysm Based on Long-Term Visual Morbidity

Clipping of paraclinoid aneurysm is still challenging because of poor visual morbidity. The extradural temporopolar approach was applied to clip paraclinoid aneurysms, with the expectation of reducing visual morbidity. Factors related to poor visual morbidity were evaluated, to assess the results for clipping of paraclinoid aneurysms. A series of 40 unruptured paraclinoid aneurysms in 38 patients were clipped via extradural temporopolar approach. Preoperative and postoperative states of visual cognitive function and radiological outcomes were investigated. Aneurysms were classified into dorsal type or non-dorsal type, and small (<9 mm) or not-small (≥9 mm), respectively, to identify factors correlated with visual morbidity. Complete clipping rate was 90.0% without any recurrence (mean: 5.2 years). Visual morbidity was unexpectedly high at 28.9%, including 2.7% of blindness immediately after the operation, and 23.7% and 2.7% at the final examination (mean: 3.6 years). Multivariate analysis showed aneurysm size was significantly correlated with worse visual outcome. Visual morbidity was 13.3% and 11.1% for dorsal and the non-dorsal small aneurysms, respectively, and all these cases showed visual field defect limited to the nasal quadrant without decreased visual acuity. In contrast, the non-dorsal not-small aneurysms showed significantly worse visual morbidity (60%) with decreased visual acuity. Clipping via extradural temporopolar approach can achieve durable treatment for small unruptured paraclinoid aneurysms with acceptable visual morbidity. Visual morbidity of the not-small non-dorsal type, however, was poor. The indications for clipping of paraclinoid aneurysm should be limited to small aneurysms, especially the dorsal type in young patients.

Surgical Strategies for Ruptured Complex Aneurysms Using Skull Base Technique and Revascularization Surgeries.

Object:Surgical clipping of paraclinoid aneurysm, thrombosed large aneurysm, and/or vertebral-basilar dissecting aneurysms can be very difficult and has relatively high morbidity. We describe our experience using skull base and bypass technique and discuss the advantages and its pitfalls.Patients and Methods:We retrospectively reviewed medical charts of 22 consecutive patients with complex aneurysmal lesions underwent skull base and/or bypass techniques between March 2012 and April 2017.Results:There were 5 patients with paraclinoid or internal carotid artery (ICA) aneurysm underwent modified extradural temporopolar approach with mini-peeling of the dura propria with suction decompression, 3 patients with ICA aneurysm underwent intradural anterior clinoidectomy, 12 patients with vertebral dissecting aneurysm through transcondylar fossa approach (6 patients underwent occipital artery-posterior inferior cerebellar artery [OA-PICA] bypass), 1 patients with vertebral artery dissection underwent superficial temporal artery-superior cerebellar artery and OA-PICA bypass through posterior transpetrosal approach, 1 patient with arteriovenous fistula at the ventral side of the craniovertebral junction through extremely far lateral approach. Surgical outcome was good recovery in 10 patients, moderate disability in 4, severe disability in 4, vegetative state in 2, and dead is 2 patients. The favorable outcome was 63.6%, and poor outcome was 36.4%, which showed poor grade subarachnoid hemorrhagic patients. No patient suffered any complication related to re-rupture and/or incomplete clipping.Conclusion:Skull base technique, which can create a wide and shallow operative space, allowed us to improve surgical outcome and to reduce the risk of intraoperative neurovascular injury for surgical treatment of deeply located complex aneurysms.

Less Invasive Modified Extradural Temporopolar Approach for Paraclinoid Lesions: Operative Technique and Surgical Results in 80 Consecutive Patients.

Background Extradural temporopolar approach for paraclinoid lesions can provide extensive and early exposure of the anterior clinoid process, and complete mobilization and decompression of the optic nerve and internal carotid artery, which can prevent intraoperative neurovascular injury. The present study investigated the usefulness of our less invasive modified technique and discussed its operative nuances. Methods We retrospectively reviewed medical charts of 80 consecutive patients with neoplastic (21 patients) and vascular lesions (59 patients) who underwent the modified extradural temporopolar approach between September 2009 and March 2014. Results Preoperative visual acuity worsened in 4 patients (5.0%) and worsening of visual field function occurred in 10 patients (12.5%). Postoperative outcome was good recovery in 71 patients, moderate disability in 6, severe disability in 2, and death in 1 (due to reruptured aneurysm). No operation-related mortality occurred in the series. Conclusion Less invasive modified extradural temporopolar approach is safe and can be recommended for the surgical treatment of deeply located aneurysms and skull base tumors to reduce the risk of intraoperative optic neurovascular injury.

Modified extradural temporopolar approach with suction decompression for clipping of large paraclinoid aneurysm: Technical note

Background:Surgical clipping of complicated large paraclinoid aneurysms are still challenging because strong adhesion of aneurysm itself may hinder the dissection of the perforators and the surrounding anatomical structures from the aneurysm dome.Methods:We describe 13 consecutive patients and the clipping of complicated, large-sized paraclinoid aneurysms using a modified extradural temporopolar approach combined with retrograde suction decompression and discuss its advantages and pitfalls.Results:Modified extradural temporopolar approach with suction decompression (SD) assistance was performed in all patients. There was no complication related to the surgical procedure. Postoperative outcome was good recovery in 7 patients, moderate disability in 4, and severe disability in 2 caused by severe subarachnoid hemorrhage. Favorable outcomes were achieved in 10 patients (84.6%).Conclusion:We recommend its less invasive, safe, and useful combined technique in the treatment of symptomatic paraclinoid aneurysms, which carry the risk of neurovascular injury caused by dissection from the aneurysm dome.

Modified extradural temporopolar approach with mini-peeling of dura propria for paraclinoid and/or parasellar tumors: Operative technique and nuances.

Background:Modified extradural temporopolar approach (EDTPA) with mini-peeling of the dura propria can provide extensive exposure of the anterior clinoid process and early exposure, as well as complete mobilization and decompression of the optic nerve and internal carotid artery, which can prevent intraoperative neurovascular injury for paraclinoid and/or parasellar lesions. The present study investigated the usefulness of this modified technique and discusses the operative nuances.Methods:We retrospectively reviewed medical charts of 27 consecutive patients with neoplastic paraclinoid and/or parasellar lesions who underwent this modified approach between September 2009 and August 2016.Results:Preoperative visual acuity worsened in 2 patients (7.4%), and worsening of visual field function occurred in 2 patients (7.4%). Postoperative outcome was good recovery in 25 patients (92.6%) and moderate disability in 2 (7.4%). No operation-related mortality occurred in the series.Conclusions:The modified EDTPA is safe and recommended for surgical treatment of paraclinoid and/or parasellar tumors to reduce the risk of intraoperative optic neurovascular injury.

Modified extradural temporopolar approach with suction decompression for clipping of large paraclinoid aneurysm: Technical note

Background: Cardiovascular diseases (CVD) are considered major health and economic burdens throughout the world. This study was conducted to estimate the magnitude of three major CVD (hypertension, ischemic heart diseases (IHD) and stroke), their risk factors, prevention and, control plan. Methods: The study design was cross-sectional. Multi-stage random sampling technique was used at different schools in Benghazi, Libya. A sample of 1200 teachers was randomly selected. Three formats were used for data collection. These included a self-administered questionnaire, a standardized Rose CVD interview questionnaire, as well as a special form for collecting data on the following: anthropometric measurements, blood pressure, clinical examination, as well as results of laboratory findings, and ECG tracings. Results: The prevalence of hypertension and IHD were 15.1% and 2.7% respectively while no cases of stroke could be detected in the study-sample. The selected CVD were found to be independently predicted by age, gender, family history of hypertension, BMI, smoking index, fasting blood sugar level, and HDL (CI 95%). Conclusion: Risk factors for hypertension & IHD among schoolteachers in Benghazi, Libya included age, BMI, fasting blood sugar, gender, smoking index, HDL, & family history of hypertension. There is thus an urgent need for intensive health education interventions for this group. There is also a need to initiate an implementation of a national program for CVD risk factors assessment, as well as promotion of an overall healthy lifestyle for school teachers through the use of health education which should be directed to smoking health related problems.

Radical Resection of a Craniopharyngioma via the Extradural Temporopolar Approach

Objective: Though the extradural temporopolar approach (EDTPA) is useful, there are only few reports of this approach being used for craniopharyngioma resection. Herein, we report our surgical case series and the technical importance of EDTPA for the radical removal of a craniopharyngioma.

Usefulness of Suction Decompression Method Combined with Extradural Temporopolar Approach During Clipping of Complicated Internal Carotid Artery Aneurysm

Surgical clipping of complicated internal carotid artery (ICA) aneurysms can be very difficult because strong adhesion may hinder dissection of the perforators and surrounding anatomical structures from the aneurysm dome. We describe our experience in the clipping of these aneurysms using retrograde suction decompression (RSD) combined with extradural temporopolar approach (ETA) and discuss its advantages and pitfalls. This retrospective study included 30 consecutive patients with complicated ICA aneurysms treated by direct clipping with RSD assistance between March 2004 and March2015. The aneurysms were located on the paraclinoid ICA in 20 cases, the posterior communicating artery bifurcation in 8, ICA bifurcation in 1, and the anterior wall of the ICA in 1. No patient suffered any complication related to the puncture of the common carotid artery. Surgical outcome was good recovery in 20 patients, moderate disability in 4, severe disability in 4, and vegetative state in 1. One patient died of re-rupture of the aneurysm caused by incomplete dome clipping. Two patients suffered cerebral infarction, caused by anterior choroidal artery infarction in 1 patient. Retrograde suction decompression combined with ETA is a useful technique for clipping of complicated ICA aneurysms.

Operative surgical nuances of modified extradural temporopolar approach with mini-peeling of dura propria based on cadaveric anatomical study of lateral cavernous structures.

Background:Extradural temporopolar approach (ETA) has been modified as less invasive manner and named as trans-superior orbital fissure (SOF) approach with mini-peeling technique. The present study discusses the operative nuances of this modified technique on the basis of cadaveric study of lateral cavernous structures.Methods:In five consecutive cadaveric specimens, we performed an extradural anterior clinoidectomy with mini-peeling of the dura propria to expose the anterior clinoid process entirely. We also investigated the histological characteristics of the lateral cavernous sinus (CS) between the dura propria and periosteal dura at the SOF, foramen rotundum (FR), and foramen ovale (FO) levels, and of each trigeminal nerve division.Results:Coronal histological examination of the lateral wall of the CS showed invagination of the dura propria and periosteal dura into the SOF. In contrast, no such invagination was observed at the levels of the FR and FO. This finding supports the technical rationale of the only skeletonization of the SOF for peeling of the dura propria but not FR. In addition, our modified ETA method needs only minimal dural incision between the SOF and FR where no cranial nerves are present.Conclusion:Our technical modification of ETA may be recommended for surgical treatment of paraclinoid lesions to reduce the risk of intraoperative neurovascular injury.

Microsurgical management of aneurysms of the superior cerebellar artery - lessons learnt: An experience of 14 consecutive cases and review of the literature.

Objective:This is a retrospective study from January 2002 to December 2012 analyzing the results of microsurgical clipping for aneurysms arising from the superior cerebellar artery (SCA).Materials and Methods:All patients with SCA were evaluated with computerized tomography angiography and/or digital subtraction angiography (DSA) prior to surgery. All patients in our series underwent microsurgical clipping and postoperative DSA to assess the extent of aneurysm occlusion. The Glasgow outcome scale (GOS) and the modified Rankin's scale (mRS) were used to grade their postoperative neurological status at discharge and 6 months, respectively.Results:Fourteen patients had SCA aneurysms (ruptured-9, unruptured-5). There were 10 females and 4 males with the mean age of 47.2 years (median - 46 years, range = 24–66 years). Subarachnoid hemorrhage (SAH) was seen in 11 patients. The mean duration of symptoms was 2.5 days (range = 1–7 days). The WFNS score at presentation was as follows: Grade 1 in 10 cases, II in 2 cases, III in 1 case and IV in 1 case. In the 9 cases with ruptured SCA aneurysm, average size of the ruptured aneurysms was 7.3 mm (range = 2.5–27 mm, median = 4.9 mm). The subtemporal approach was used in the first 7 cases. The extradural temporopolar (EDTP) approach was used in the last 5 cases. Complications include vasospasm (n = 6), third nerve palsy (n = 5) and hydrocephalus (n = 3). Two patients died following surgery. At mean follow-up 33.8 months (median - 25 months, range = 19–96 months), no patient had a rebleed. At discharge 9 (64%), had a GOS of 4 or 5 and 3 (21%) had a GOS of 3. At 6 months follow-up, 10/14 (71%) patients had mRS of 0–2, and 2 (14%) had mRS of 5.Conclusions:Aneurysms of the SCA are uncommon and tend to rupture even when the aneurysm size is small (<7 mm). They commonly present with SAH. The EDTP approach avoids complication caused by temporal lobe retraction and injury to the vein of Labbe.

Extradural temporopolar approach for surgical management of paraclinoid lesions

Surgical treatment of paraclinoid tumors adjacent to important anatomical structures, such as the optic nerve, optic chiasm, pituitary stalk, and internal carotid artery, should emphasize maximum resection and preservation of visual function. Thus, early localization and exposure of the optic nerve, and complete mobilization and decompression of the optic nerve and internal carotid artery, are necessary in order to prevent intraoperative neurovascular injuries. However, this technique requires wide exposure of the optic-carotid space through the interpeduncular cistern. We have developed an extradural temporopolar approach for resection of paraclinoid tumors, which can also allow early devascularization of arteries that feed the tumors. We evaluated the surgical outcomes of this approach, paying special attention to clinical and visual outcomes. Thirteen patients(4 men, 9 women;24-78 years, mean age 54 years), underwent tumor removal using an extradural temporopolar approach between March 2000 and April 2013. We retrospectively reviewed medical charts, radiological findings, intensive care unit flow sheets, and surgical records. Histological diagnoses included craniopharyngioma(4 cases), pituitary adenoma(3 cases), medial sphenoid ridge meningioma(2 cases), tuberculum sellae meningioma(2 cases), trigeminal neurinoma(1 case), and malignant epidermoid(1 case). Tumors were 1.5-6.0cm in length(mean 3.2cm). Tumors were cystic in all 4 craniopharyngiomas and solid in the other 9 cases. Preoperative neurological deficits included visual disturbance in 10 patients, double vision caused by oculomotor nerve palsy in 2 patients, and vertigo in 1 patient. Additional orbitozygomatic craniotomies were performed in 8 patients. Total tumor removal was performed in 7 patients and subtotal removal performed in 6. The pituitary stalk was microscopically preserved in all patients. Postoperative complications included transient diabetes insipidus in 2 patients, chronic subdural hematoma in 1 patient, and abducens palsy in 1 patient. All complications were completely resolved. Surgical outcomes on discharge were recorded as follows:good recovery(11 patients), moderate disability(1 patient), and severe disability(1 patient, who suffered preoperative consciousness disturbance). Visual outcomes were improved in 7 patients, unchanged in 5, and worsened in 1, with recurrence. The present extradural temporopolar approach, which allows early decompression of the optic nerve, and early devascularization and detachment of the tumor, may lead to greater tumor resection and improved visual outcomes in patients with paraclinoid tumors.

Extradural temporopolar approachによる未破裂脳底動脈瘤や傍床部内頚動脈瘤のclipping術

Basilar artery and internal carotid paraclinoid aneurysms are still surgically challenging. We performed 31 clipping surgeries (basilar tip aneurysm 6, basilar artery-superior cerebellar artery aneurysm 8, and internal carotid aneurysm 17) via the extradural temporopolar approach. After the frontotemporal craniotomy, the meningo-orbital band was incised and the dura propria of the temporal lobe was peeled from the lateral wall of the cavernous sinus. The anterior clinoid process was removed extradurally. The distal dural ring and falciform ligament were incised for mobilization of the internal carotid artery and optic nerve. The temporal lobe was retracted posteriorly with the dura mater. The aneurysm clipping was performed through the relatively wide operative trajectory over the opened cavernous sinus. Postoperative outcome was modified Rankin Scale (mRS) 0 in 28 patients and mRS in three patients with visual deficits. No temporal lobe contusion occurred. The extradural temporopolar approach is a useful skull base technique for deeply situated aneurysms.

Development of Artificial Cranial Base Model With Soft Tissues for Practical Education

Improved educational tools for anatomic understanding and surgical simulation of the cranial base are needed because of the limited opportunities for cadaver dissection. A 3-dimensional cranial base model with retractable artificial dura mater is essential to simulate the epidural cranial base approach. We developed our 3-dimensional cranial base model with artificial dura mater, venous sinuses, cavernous sinus, internal carotid artery, and cranial nerves, and the extradural temporopolar approach was simulated using this new model. This model can be dissected with a surgical drill because of the artificial bone material. The periosteal dura was reconstructed in the medial wall of the cavernous sinus, periorbita, and periosteal bridge in the superior orbital fissure with yellow silicone. The meningeal dura was made with brown silicone. The single-layer dura mater could be dissected from the bone surface and retracted with a surgical spatula. Extradural drilling of the superior orbital fissure and opening of the optic canal were similar to actual surgery. Extradural anterior clinoidectomy was performed via the extradural space by retracting the artificial dura mater. The artificial dura propria of the lateral wall in the cavernous sinus was successfully peeled from the artificial cranial nerves to complete the extradural temporopolar approach. The improved 3-dimensional cranial base model provides a useful educational tool for the anatomic understanding and surgical simulation of extradural cranial base surgery.

Anterior temporal approachとExtra-dural temporopolar approach : 脳底動脈先端部動脈瘤および後方向き内頚動脈瘤に対して(&lt;特集&gt;手術アプローチの選択とピットフォールI-第24回微小脳神経外科解剖セミナーより-)

脳底動脈先端部動脈瘤と後方向き内頚動脈瘤に対するanterior temporal approachとextra-dural temporopolar approachの手術解剖について概説した.anterior temporal approachはdistalのsylvian fissureからuncusの周囲まで剥離し,側頭葉を後方にretractすることにより内頚動脈の背側に広い空間を確保することができる.その広い空間から脳底動脈先端部周囲の解剖をも確認しうる.しかしsuperficial sylvian veinの還流形態によっては術中にextra-dural tempolopolar approachへの変更により,十分な空間の確保が可能である.extra-dural temporopolar approachを行う際には,meningo-orbital band,前床突起,硬膜輪,海綿静脈洞の手術解剖を理解する必要がある.

The extradural temporopolar approach: a review of indications and operative technique

The extradural temporopolar approach is used for enhanced exposure of the cavernous sinus and petroclival regions in the treatment of complex lesions not amenable to sole treatment via radiosurgical or endovascular methods. The authors' objective was to review the indications, surgical experience, and operative technique in a series of patients who underwent surgery with this approach. The authors conducted a retrospective review to identify patients who underwent a temporopolar approach from 1992 to 2008. An orbitozygomatic craniotomy was frequently used, followed by extradural retraction of the temporal lobe. A sequential progression of bone removal at the anterior and middle skull base, followed by opening the layers of the lateral wall of the cavernous sinus was next performed to safely retract the brain and widen the exposure to the cavernous sinus, interpeduncular fossa, and upper petroclival regions. Sixty-six patients were identified and included in the study. The mean patient age was 49 years. The main indications for surgery were as follows: meningioma (25 patients, 38%), basilar artery aneurysm (11 patients, 17%), trigeminal schwannoma (7 patients, 11%), chordoma (5 patients, 7%), hemangioma (3 patients, 5%), pituitary adenoma (3 patients, 5%), superior cerebellar artery aneurysm (3 patients, 5%), and other lesions (9 patients, 14%). Complications included hemiparesis in 4 patients (6%), infarcts in 4 patients (6%), transient aphasia in 1 patient (1.5%), and cranial nerve paresis in 20 patients (30%). The extradural temporopolar approach offers a relatively safe and wide exposure of the sphenocavernous and petroclival regions. Mobilization of the cranial nerves and internal carotid artery allow gentle brain retraction and maximal preservation of venous outflow. This is an advantageous approach to large tumors in these regions and for complex upper basilar artery or superior cerebellar artery aneurysms.

Ｈｉｇｈ ｐｏｓｉｔｉｏｎ ＢＡ‐ＳＣＡ ａｎｅｕｒｙｓｍに対するｃｒａｎｉｏ‐ｏｒｂｉｔａｌ Ｄｏｌｅｎｃ’ｓ ａｐｐｒｏａｃｈの有用性

We report a case of high-position BA-SCA aneurysm operated by 2 different approaches—pterional and cranio-orbital Dolenc's approach—. A 48-year-old woman presented with severe headache and vomiting without neurological deficit. CT scan demonstrated subarachnoid hemorrhage localized in the right Sylvian fissure. Cerebral angiogram showed right MCA ruptured and left BA-SCA unruptured aneurysms. After clipping of the right MCA aneurysm, a left BA-SCA aneurysm was explored by the same pterional approach. However, it was impossible to clip completely because of narrow and deep operative field. Four months later, the same left BA-SCA aneurysm was well explored and clipped successfully by left cranio-orbital Dolenc's approach. The cranio-orbital craniotomy gives a wide and shallow operative field, and Dolenc's approach gives working space around carotid artery by dissecting the distal ring and the optic canal. For the high-position distal basilar artery aneurysms, there are many reports of approaches such as zygomatic approach and extradural temporo-polar approach to complete clipping safely. The cranio-orbital Dolenc's approach is thought to be useful.

The surgical management of trigeminal neuromas.

Trigeminal neuromas are rare tumors that may involve any part of the nerve complex, including peripheral divisions of the nerve. These rare lesions are treated primarily surgically. We present our series of 38 patients who were treated surgically since 1981, with special emphasis on surgical approach. We have surgically treated 38 patients with 39 trigeminal neuromas since 1981. This series of patients was reviewed with regard to clinical presentation, tumor characteristics, surgical approach, and outcome. Sixteen women and 22 men (mean age, 48 yr) all presented with some abnormality of trigeminal dysfunction. Twenty-eight patients presented with trigeminal hypesthesia, 10 with hypesthesia also had facial pain, 3 presented with only facial pain, and 7 presented with diplopia. Eighteen patients had tumors originating from the ganglion, nine from the posterior fossa nerve root, two from the ophthalmic division, and one from the mandibular division, and nine had tumors involving both posterior and middle fossae (dumbbell type). Eighteen tumors were large (>3 cm), 16 were medium sized (2-3 cm), and 5 were small (<2 cm). Tumor location was the prime determinant of surgical approach. Patients with peripheral and ganglion type lesions were treated via an entirely extradural temporopolar approach. Lesions confined to the posterior fossa were approached via a lateral suboccipital approach. Dumbbell-shaped lesions required a combined petrosal strategy. Total resection of tumor was accomplished in 30 patients. Three patients with subtotal resection displayed malignant histology. Postoperatively, 30 patients remained with some degree of trigeminal hypesthesia, two had facial pain (one persistent and one new), and five were left with total trigeminal anesthesia. Four patients were relieved of diplopia, five were relieved of headache, and two were relieved of ataxia. There were no perioperative deaths. Trigeminal neuroma is a surgically treatable disease that may be operated on, in many cases, via an entirely extradural approach. These lesions may be successfully resected with low morbidity and a very low rate of recurrence.

Extradural temporopolar approach to lesions of the upper basilar artery and infrachiasmatic region.

Surgical access to the parasellar, infrachiasmatic, and posterior clinoid regions has traditionally been accomplished through an intradural pterional or subtemporal approach. However, for large or complex lesions in these locations, such traditional trajectories may not afford sufficient exposure for complete obliteration of the pathological process. The authors describe an anterolateral transcavernous approach to this region that includes the following components: 1) extradural removal of the sphenoid wing and exposure of the superior orbital fissure and foramen rotundum; 2) removal of the anterior clinoid process via the anterolateral route; 3) decompression of the optic canal; 4) extradural retraction of the temporal tip; 5) transcavernous mobilization of the carotid artery and third cranial nerve; and 6) removal of the posterior clinoid process. This method results in enhanced exposure with minimal brain retraction and preservation of the temporal tip bridging veins. This approach has been used in 22 patients: 10 with basilar top aneurysms, eight with craniopharyngiomas, one with a tuberculum sellae meningioma, and two with trigeminal neuromas; the last patient had a carotid-cavernous fistula and a concomitant pituitary adenoma. Complete clip ligation was performed for all 10 basilar artery aneurysms, and gross total resection was achieved with preservation of the pituitary stalk in all tumor cases. Microscopic total resection was not possible in two cases of craniopharyngioma due to hypothalamic invasion. Two patients suffered transient postoperative hemiparesis, and one patient has persisting weakness; however, no patient followed for more than 6 months suffered any persistent cranial nerve morbidity. It is concluded that this procedure can serve as an alternative to either the transsylvian or subtemporal approaches when cranial base pathologies are large or complex.