UpToDate: Internal carotid artery segments

Internal carotid artery segments

The course of the internal carotid artery (ICA) and its segment classifications were reviewed by means of a new and freely available interactive 3D model of the artery and the skull base, based on human neuroimages, that can be freely downloaded at the Public Repository of the University of Barcelona ( http://diposit.ub.edu/dspace/handle/2445/112442 ) and runs under Adobe Acrobat Reader in Mac and Windows computers and Windows 10 tablets. The 3D-PDF allows zoom, rotation, selective visualization of structures, and a predefined sequence view. Illustrative images of the different classifications were obtained 1).

In 1938 Fischer, described five internal carotid artery segments in the opposite direction to the blood flow 2).

These segments were based on the angiographic course of the intracranial ICA rather than its arterial branches or anatomic compartments. Subsequent attempts to apply modern nomenclature to these numerical segments failed to recognize Fischer’s original intent of describing patterns of arterial displacement by tumors and, therefore, resulted in a nomenclature that was anatomically inaccurate. Fischer’s system was further limited, because segments were numbered opposite the direction of blood flow and the extracranial ICA was excluded 3).


Gibo et al. in 1981 studied the microsurgical anatomy of the supraclinoid portion of the internal carotid artery (ICA) in 50 adult cadaver cerebral hemispheres using X 3 to X 40 magnification. The ICA was divided into four parts: the C1 or cervical portion; the C2 or petrous portion; the C3 or cavernous portion; and the C4 or supraclinoid portion.

The C4 portion was divided into three segments based on the origin of its major branches: the ophthalmic segment extended from the origin of the ophthalmic artery to the origin of the posterior communicating artery (PCoA); the communicating segment extended from the origin of the PCoA to the origin of the anterior choroidal artery (AChA); and the choroidal segment extended from the origin of the AChA to the bifurcation of the carotid artery. Each segment gave off a series of perforating branches with a relatively constant site of termination. The perforating branches arising from the ophthalmic segment passed to the optic nerve and chiasminfundibulum, and the floor of the third ventricle. The perforating branches arising from the communicating segment passed to the optic tract and the floor of the third ventricle. The perforating branches arises from the choroidal segment passed upward and entered the brain through the anterior perforated substance. The anatomy of the ophthalmic, posterior communicating, anterior choroidal, and superior hypophyseal branches of the C4 portion was also examined. Gibo-Rothon (J Neurosurg 55:560-574, 1981) follow the blood flow, incorporated the cervical and petrous portions, and divided the subarachnoid course-supraclinoid-in ophthalmic, communicating, and choroidal segments, enhancing transcranial microscopic approaches 4).


see Bouthillier classification.

Bouthillier et al. described in 1996 a seven segment internal carotid artery (ICA) classification system. It remains the most widely used system for describing ICA segments.


The Kassam’s group (2014), with an endoscopic endonasal perspective, introduces the “paraclival segment,” including the “lacerum segment” and part of the intracavernous ICA, and details surgical landmarks to minimize the risk of injury 5).

see also Carotid Siphon

AC: anterior clinoid process; ICA: internal carotid artery; LT: lamina terminalis; ON: optic nerve; OlN; olfactory nerve; SW: sphenoid wing; TS: tuberculum sellae; A1: A1 segment of the Anterior Cerebral Artery; A2: A2 segment of the Anterior Cerebral Artery; M1: M1 segment of the Middle Cerebral Artery

Endoscopic classification

Based on anatomic correlations, the ICA may be described as 6 distinct segments:

(1) parapharyngeal (common carotid artery bifurcation to carotid canal)

(2) petrous (carotid canal to posterolateral aspect of foramen lacerum)

(3) paraclival (posterolateral foramen lacerum to the superomedial aspect of the petrous apex)

(4) parasellar (superomedial petrous apex to the proximal dural ring)

(5) paraclinoid (from the proximal to the distal dural rings)

(6) intradural (distal ring to ICA bifurcation).

Corresponding surgical landmarks included the Eustachian tube, the fossa of Rosenmüller, and levator veli palatini for the parapharyngeal segment; the vidian canal and V3 for the petrous segment; the fibrocartilage of foramen lacerumforamen rotundummaxillary strut, lingular process of the sphenoid bone, and paraclival protuberance for the paraclival segment; the sellar floor and petrous apex for the parasellar segment; and the medial and lateral opticocarotid and lateral tubercular recesses, as well as the distal osseous arch of the carotid sulcus for the paraclinoid segment 6).

see Intracavernous internal carotid artery.

References

1)

Melé MV, Puigdellívol-Sánchez A, Mavar-Haramija M, Juanes-Méndez JA, Román LS, De Notaris M, Catapano G, Prats-Galino A. Review of the main surgical and angiographic-oriented classifications of the course of the internal carotid artery through a novel interactive 3D model. Neurosurg Rev. 2018 Jul 26. doi: 10.1007/s10143-018-1012-7. [Epub ahead of print] Review. PubMed PMID: 30051302.
2)

Fischer E. Die Lageabweichungen der vorderen hirnarterie im gefässbild. Zentralbl Neurochir. 1938;3:300–313.
3)

Bouthillier A, van Loveren HR, Keller JT. Segments of the internal carotid artery: a new classification. Neurosurgery. 1996 Mar;38(3):425-32; discussion 432-3. PubMed PMID: 8837792.
4)

Gibo H, Lenkey C, Rhoton AL Jr. Microsurgical anatomy of the supraclinoid portion of the internal carotid artery. J Neurosurg. 1981 Oct;55(4):560-74. PubMed PMID: 7277004.
5) , 6)

Labib MA, Prevedello DM, Carrau R, Kerr EE, Naudy C, Abou Al-Shaar H, Corsten M, Kassam A. A road map to the internal carotid artery in expanded endoscopic endonasal approaches to the ventral cranial base. Neurosurgery. 2014 Sep;10 Suppl 3:448-71. doi: 10.1227/NEU.0000000000000362. PubMed PMID: 24717685.

UpToDate: Osteoporotic vertebral fracture treatment

Osteoporotic vertebral fracture treatment

Initial therapy for osteoporotic vertebral compression fractures (OVCF) are bed rest, orthotic devices and pain medication 1) 2).

However, some patients fail to benefit from these treatment modalities and disease-related morbidity and mortality persists. Conservatively treated OVCF’s are cured with partial relief of pain and quality of life within 2 to 12 weeks 3) 4)

Kyphoplasty was developed to restore vertebral height and improve sagittal alignment. Several studies have shown these theoretical improvements cannot be transferred universally to the clinical setting.

see Vertebral augmentation.

The treatment of osteoporotic vertebral compression fractures using transpedicular cement augmentation has grown significantly since 1990s.

The treatment of painful vertebral compression fractures has changed substantially since the introduction of vertebroplasty in the mid-1980s and balloon kyphoplasty in the late 1990s. Both procedures were widely accepted with the vertebral fractures treated reaching 150,000 per annum in 2009 prior to the publication of 2 randomized controlled trials comparing vertebroplasty with a sham treatment published in the New England Journal of Medicine in August 2009. Since then, there has been a flood of information on vertebral augmentation and balloon kyphoplasty. It is worth evaluating this information especially because it relates to current recommendations that are often followed blindly by medical and administrative groups unfamiliar with either the procedure or the high level of evidence surrounding vertebral augmentation 5).


In a multicenter study, Kallmes et al., randomly assigned 131 patients who had one to three painful osteoporotic vertebral compression fractures to undergo either vertebroplasty or a simulated procedure without cement (control group). The primary outcomes were scores on the modified Roland Morris Disability Questionnaire (RDQ) (on a scale of 0 to 23, with higher scores indicating greater disability) and patients’ ratings of average painintensity during the preceding 24 hours at 1 month (on a scale of 0 to 10, with higher scores indicating more severe pain). Patients were allowed to cross over to the other study group after 1 month.

All patients underwent the assigned intervention (68 vertebroplasties and 63 simulated procedures). The baseline characteristics were similar in the two groups. At 1 month, there was no significant difference between the vertebroplasty group and the control group in either the RDQ score (difference, 0.7; 95% confidence interval [CI], -1.3 to 2.8; P=0.49) or the pain rating (difference, 0.7; 95% CI, -0.3 to 1.7; P=0.19). Both groups had immediate improvement in disability and pain scores after the intervention. Although the two groups did not differ significantly on any secondary outcome measure at 1 month, there was a trend toward a higher rate of clinically meaningful improvement in pain (a 30% decrease from baseline) in the vertebroplasty group (64% vs. 48%, P=0.06). At 3 months, there was a higher crossover rate in the control group than in the vertebroplasty group (51% vs. 13%, P<0.001) [corrected]. There was one serious adverse event in each group.

Improvements in pain and pain-related disability associated with osteoporotic compression fractures in patients treated with vertebroplasty were similar to the improvements in a control group 6).

On the other hand a randomized controlled trial (Fracture Reduction Evaluation [FREE] trial) which took place at 21 sites in eight countries and included 149 patients assigned to balloon kyphoplasty showed that in patients with acute, painful, vertebral fractures, balloon kyphoplasty improved quality of life, function, mobility, and pain more rapidly than did nonsurgical management, with significant differences in improvement between the groups at 1 month 7).

References

1)

Riek AE, Towler DA. The pharmacological management of osteoporosis. Mo Med. 2011;108:118–123.

2)

Rapado A. General management of vertebral fractures. Bone. 1996;18:191S–196S.

3)

Brown CJ, Friedkin RJ, Inouye SK. Prevalence and outcomes of low mobility in hospitalized older patients. J Am Geriatr Soc. 2004;52:1263–1270.

4)

Babayev M, Lachmann E, Nagler W. The controversy surrounding sacral insufficiency fractures: to ambulate or not to ambulate? Am J Phys Med Rehabil. 2000;79:404–409.

5)

Beall DP, McRoberts WP, Berven SH, Ledlie JT, Tutton SM, Parsons BP. Critique of the Analysis of UpToDate.com on the Treatment of Painful Vertebral Compression Fractures: Time to Update UpToDate. AJNR Am J Neuroradiol. 2014 Nov 20. [Epub ahead of print] PubMed PMID: 25414003.

6)

Kallmes DF, Comstock BA, Heagerty PJ, Turner JA, Wilson DJ, Diamond TH, Edwards R, Gray LA, Stout L, Owen S, Hollingworth W, Ghdoke B, Annesley-Williams DJ, Ralston SH, Jarvik JG. A randomized trial of vertebroplasty for osteoporotic spinal fractures. N Engl J Med. 2009 Aug 6;361(6):569-79. doi: 10.1056/NEJMoa0900563. Erratum in: N Engl J Med. 2012 Mar 8;366(10):970. PubMed PMID: 19657122; PubMed Central PMCID: PMC2930487.

7)

Wardlaw D, Cummings SR, Van Meirhaeghe J, Bastian L, Tillman JB, Ranstam J, Eastell R, Shabe P, Talmadge K, Boonen S. Efficacy and safety of balloon kyphoplasty compared with non-surgical care for vertebral compression fracture (FREE): a randomised controlled trial. Lancet. 2009 Mar 21;373(9668):1016-24. doi: 10.1016/S0140-6736(09)60010-6. Epub 2009 Feb 24. PubMed PMID: 19246088.

UpToDate: Pituicytoma

Pituicytoma

Pituicytoma is a rare glial sellar/suprasellar neoplasm arising in the neurohypophysis with a possible origin from the folliculostellate cells of the adenohypophysis which are non-endocrine spindled cells expressing S-100 and Bcl-2 1) 2).

Pituicytoma is considered to be a distinct Grade I neoplasm 3).

Although usually intra-sellar, pituicytomas can have suprasellar extension; however, purely suprasellar examples although rare have been reported 4).

Epidemiology

PTs had a higher prevalence in the fifth and sixth decades of life, with a slight male predominance. 5).

Clinical features

The presenting symptoms are due to the mass effect of the tumor and include visual disturbances caused by direct compression on the optic chiasm, headaches, endocrinological symptoms and rarely diabetes insipidus 6).

Diagnosis

Radiologically, PTs were found anywhere along the hypothalamic-pituitary axis mimicking other, more frequent tumors growing in this anatomical region 7).

The MRI features are non-specific with most case reports showing a solid, homogenous mass, iso-intense on T1-weighted images and hyper-intense on T2-weighted images with homogenous contrast enhancement 8).

Amongst the various sellar tumors, pituicytoma and spindle cell oncocytoma (SCO) have considerable overlap in histological, Immunohistochemical (IHC) profile and can have extensive intraoperative bleeding making complete excision difficult with increased chances of recurrence. It is important to differentiate pituicytoma from SCO since the former is associated with a slightly better prognosis with recurrence being uncommon after complete surgical excision. Till 2013, out of 29 cases of pituicytoma with a detailed follow-up, recurrence was seen in six cases, all of which were found to have an incomplete resection during the first surgery 9).

SCO on the other hand have a tendency to recur even after complete excision. Hence, it is advocated to combine surgery with adjuvant radiotherapy in all cases of SCO to reduce the chances of recurrence. EMA is strongly positive in SCO, thus it can help to differentiate pituicytoma from SCO 10).

Subtypes

TTF-1 Expressing Sellar Neoplasm with Ependymal Rosettes and Oncocytic Change: Mixed Ependymal and Oncocytic Variant 11).

Treatment

Review

Less than 50 cases have been reported in the world literature till 2013 12).

Salge-Arrieta et al., from the Hospital Universitario Ramón y Cajal Madrid, Spain, published a retrospective review of case reports published in the scientific literature to 2018, including a new illustrative example treated.

116 cases were collected. PTs had a higher prevalence in the fifth and sixth decades of life, with a slight male predominance. Main symptoms, which tended to be progressive, included visual field defects and pituitary-hypothalamic dysfunction. Radiologically, PTs were found anywhere along the hypothalamic-pituitary axis mimicking other, more frequent tumors growing in this anatomical region. Surgical treatment included both transcranial or transsphenoidal approaches, and resulted in gross total resection and morbidity rates of 46.8 and 59%, respectively; the latter essentially consisted in anterior and posterior pituitary dysfunction, with limited impact on daily quality of life.

Due to both low frequency and the absence of pathognomonic clinical and/or radiological features, formulating a suspicion diagnosis of PT represents a considerable challenge even for experienced professionals. The indication for treatment should be made on an individual basis, but it is inescapable in the presence of a visual field defect. The surgical approach has to be tailored according to the topography of the tumor and preoperative symptoms; the greatest challenges in accomplishing a gross total removal are represented by the degree of adherence and vascularization of the PT 13).

Case series

Lefevre et al., from the Groupe Hospitalier Pitié-Salpêtrière, Paris, France published a retrospective multicenter study, reporting the clinical manifestations, radiological characteristics, histopathological features, treatment strategies and long-term outcomes of patients who have been treated for a Pituicytoma at various institutions in Paris, France over the past 10 years. In addition, they compared the results to the world literature in order to identify similarities concerning the radiographic diagnosis and the treatment strategies of these tumors.

Eight patients were operated on in four different hospitals. Misdiagnosis was constant before surgery, pituitary adenoma or craniopharyngioma being suspected. During surgery (transsphenoidal approach: six cases, transcranial approach: two cases) unusual tumors were noted, with important bleeding in most cases. Complete resection could be obtained in five patients. Pathological diagnosis was confirmed in all cases. During the follow up two recurrences occurred. One was subsequently treated with radiotherapy, the other underwent a second surgery.

Recent updates concerning the histological diagnosis of pituicytomas should be generalized to our practice in order to provide a better understanding of this rare pathology and its natural course 14).

References

1)

Phillips JJ, Misra A, Feuerstein BG, Kunwar S, Tihan T. Pituicytoma: Characterization of a unique neoplasm by histology, immunohistochemistry, ultrastructure, and array-based comparative genomic hybridization. Arch Pathol Lab Med 2010;134:1063-9.

2)

Koutourousiou M, Gardner PA, Kofler JK, Fernandez-Miranda JC, Snyderman CH, Lunsford LD. Rare infundibular tumors: clinical presentation, imaging findings, and the role of endoscopic endonasal surgery in their management. J Neurol Surg B Skull Base. 2013 Feb;74(1):1-11. doi: 10.1055/s-0032-1329619. Epub 2012 Dec 31. PubMed PMID: 24436883; PubMed Central PMCID: PMC3699169.

3)

Louis DN, Ohgaki H, Wiestler OD, Cavenee WK, Burger PC, Jouvet A, et al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:97-109.

4)

Zhang F, Chen J, You C. Pituicytoma: Case report and review of the literature. Neurol India 2010;58:799-801.

5) , 7) , 13)

Salge-Arrieta FJ, Carrasco-Moro R, Rodríguez-Berrocal V, Pian H, Martínez-San Millán JS, Iglesias P, Ley-Urzáiz L. Clinical features, diagnosis and therapy of pituicytoma: an update. J Endocrinol Invest. 2018 Jul 20. doi: 10.1007/s40618-018-0923-z. [Epub ahead of print] Review. PubMed PMID: 30030746.

6) , 8)

Chu J, Yang Z, Meng Q, Yang J. Pituicytoma: Case report and literature review. Br J Radiol 2011;84:e55-7.

9) , 10)

Ogiwara H, Dubner S, Shafizadeh S, Raizer J, Chandler JP. Spindle cell oncocytoma of the pituitary and pituicytoma: Two tumors mimicking pituitary adenoma. Surg Neurol Int 2011;2:116.

11)

Saeed Kamil Z, Sinson G, Gucer H, Asa SL, Mete O. TTF-1 Expressing Sellar Neoplasm with Ependymal Rosettes and Oncocytic Change: Mixed Ependymal and Oncocytic Variant Pituicytoma. Endocr Pathol. 2013 Nov 16. [Epub ahead of print] PubMed PMID: 24242699.

12)

Shenoy AS, Desai HM, Mehta JK. Pituicytoma: a case report with literature revisited. Indian J Pathol Microbiol. 2013 Apr-Jun;56(2):180-1. doi: 10.4103/0377-4929.118695. PubMed PMID: 24056664.

14)

Lefevre E, Bouazza S, Bielle F, Boch AL. Management of pituicytomas: a multicenter series of eight cases. Pituitary. 2018 Jul 31. doi: 10.1007/s11102-018-0905-3. [Epub ahead of print] PubMed PMID: 30062665.
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