Cranial dural arteriovenous shunts: selection of the ideal lesion for surgical occlusion according to the classification system

Acta Neurochirurgica (2019) 161:1775–1781 

The types of cranial dural arteriovenous fistulae (cDAVFs) that constitute good surgical candidates are unclear despite the use of classifications. We aimed to compare the DES classification with other classification schemes in identifying “ideal lesions for surgery.” The DES scheme is based on two features: the level of the shunt (BVS, bridging vein shunt; DSS, dural sinus shunt; ISS, isolated sinus shunt; EVS, emissary vein shunt) and the type of leptomeningeal venous reflux (LVR) (direct, exclusive, strained).

In this observational cohort study, the angiographies of 20 consecutive patients treated over 1 year were analyzed retrospectively. We defined cDAVFs as ideal for surgery, if cure may be achieved by disconnecting the arterialized draining vein through a single craniotomy. To evaluate the performance of each classification scheme in identifying the “ideal lesion for surgery,” we carried out a sensitivity analysis of the Borden, Cognard, and DES schemes.

Eight lesions were Borden type 3 and 1 type 2, and 11 type 1. According to Cognard, 2 lesions were type IV, 2 type III, 1 type IIa+b, 11 type I, and 4 lesions could not be clearly classified. According to the DES scheme, 8 lesions were DSS, 4 BVS, 3 ISS, and 5 EVS. All 4 lesions classified as BVS in the DES were ideal lesions for surgery (sensitivity, specificity, PPV, NPV 100%). Not all high-grade lesions according to Borden were good surgical candidates.

Conclusion The DES scheme, as opposed to other classifications, facilitates the therapeutic decision-making especially for selecting candidates for surgery.

Cranial Chordoma: A New Preoperative Grading System

Neurosurgery 83:403–415, 2018

Chordomas are rare but challenging neoplasms involving the skull base. A preoperative grading system will be useful to identify both areas for treatment and risk factors, and correlate to the degree of resection, complications, and recurrence.

OBJECTIVE: To propose a new grading system for cranial chordomas designed by the senior author. Its purpose is to enable comparison of different tumors with a similar pathology to clivus chordoma, and statistically correlate with postoperative outcomes.

METHODS: The numerical grading system included tumor size, site of the tumor, vascular encasement, intradural extension, brainstem invasion, and recurrence of the tumor either after surgery or radiotherapy with a range of 2 to 25 points; it was used in 42 patients with cranial chordoma. The grading system was correlated with number of operations for resection, degree of resection, number and type of complications, recurrence, and survival.

RESULTS: We found 3 groups: low-risk 0 to 7 points, intermediate-risk 8 to 12 points, and high-risk≥13 points in the grading system. The 3 groupswere correlated with the following: extent of resection (partial, subtotal, or complete; P < .002); number of operative stages to achieve removal (P < .014); tumor recurrence (P = .03); postoperative Karnofsky Performance Status (P < .001); and with successful outcome (P = .005). The grading system itself correlated with the outcome (P = .005).

CONCLUSION: The proposed chordoma grading system can help surgeons to predict the difficulty of the case and know which areas of the skull base will need attention to plan further therapy.

Anatomy and Pathology of the Cranial Emissary Veins: A Review With Surgical Implications

Neurosurgery 70:1312–1319, 2012 DOI: 10.1227/NEU.0b013e31824388f8

Emissary veins connect the extracranial venous system with the intracranial venous sinuses. These include, but are not limited to, the posterior condyloid, mastoid, occipital, and parietal emissary veins.

A review of the literature for the anatomy, embryology, pathology, and surgery of the intracranial emissary veins was performed.

Detailed descriptions of these venous structures are lacking in the literature, and, to the authors’, knowledge, this is the first detailed review to discuss the anatomy, pathology, anomalies, and clinical effects of the cranial emissary veins.

Our hope is that such data will be useful to the neurosurgeon during surgery in the vicinity of the emissary veins.

Endoscopic Endonasal Approach for Nonvestibular Schwannomas

Neurosurgery 69:1046–1057, 2011 DOI: 10.1227/NEU.0b013e3182287bb9

Nonvestibular schwannomas of the skull base often represent a challenge owing to their anatomic location. With improved techniques in endoscopic endonasal skull base surgery, resection of various ventral skull base tumors, including schwannomas, has become possible.

OBJECTIVE: To assess the outcomes of using endoscopic endonasal approach (EEA) for nonvestibular schwannomas of the skull base.

METHODS: Seventeen patients operated on for skull base schwannomas by EEA at the University of Pittsburgh Medical Center from 2003 to 2009 were reviewed.

RESULTS: Three patients underwent combined approaches with retromastoid craniectomy (n = 2) and orbitopterional craniotomy (n = 1). Three patients underwent multistage EEA. The rest received a single EEA operation. Data on degree of resection were found for 15 patients. Gross total resection (n = 9) and near-total (.90%) resection (n = 3) were achieved in 12 patients (80%). There were no tumor recurrences or postoperative cerebrospinal fluid leaks. In 3 of 7 patients with preoperative sensory deficits of trigeminal nerve distribution, there were partial improvements. Patients with preoperative reduced vision (n = 1) and cranial nerve VI or III palsies (n = 3) also showed improvement. Five patients had new postoperative trigeminal nerve deficits: 2 had sensory deficits only, 1 had motor deficit only, and 2 had both motor and sensory deficits. Three of these patients had partial improvement, but 3 developed corneal neurotrophic keratopathy.

CONCLUSION: An EEA provides adequate access for nonvestibular schwannomas invading the skull base, allowing a high degree of resection with a low rate of complications.