Treatment of conus medullaris arteriovenous malformation: the role of microsurgical treatment

J Neurosurg Spine 41:115–121, 2024

Conus medullaris arteriovenous malformation (AVM) is rare and challenging to treat. To better define the presentation, prognosis, and optimal treatment of these lesions, the authors present their treatment experiences for conus medullaris AVM.

METHODS Eleven patients with AVM of the conus medullaris were identified between March 2013 and December 2021. Among these patients, 7 who underwent microsurgical treatment were included. Patient data, including age, sex, symptoms at presentation, neurological status, radiological findings, nidus depth (mainly pial lesion vs intramedullary lesion), type of treatment, and recurrence at follow-up, were collected. Postoperative angiography was performed in all patients. Spinal cord function was evaluated using the Frankel grade at the time of admission and 1 year after surgery.

RESULTS All 7 patients presenting with myeloradiculopathy were treated surgically. Four patients (57.1%) underwent endovascular embolization, followed by resection. The other 3 patients underwent microsurgery only. Complete occlusion was confirmed with postoperative angiography in all patients. Of the 3 patients who were nonambulatory before surgery (Frankel grade C), 2 were able to walk after surgery (Frankel grade D) and 1 remained nonambulatory (Frankel grade C) at 1-year follow-up.

CONCLUSIONS Based on the authors’ clinical experiences, the results of multimodal treatment for conus medullaris AVM are good, with microsurgical treatment playing an important role. The microsurgical strategy can differ depending on the location of the nidus, and when possible, good results can be expected through microsurgical resection.

Intradural spinal cord arteriovenous shunts in a personal series of 210 patients

J Neurosurg Spine 34:920–930, 2021

Few classifications of intradural spinal arteriovenous shunts (ID-SAVSs) have considered their anatomical localization in relation to their phenotype and angioarchitectonics. The authors propose another vision of ID-SAVSs allowing a reappraised classification based on analysis of the anatomical disposition, angioarchitecture, and histogenetic location of these vascular malformations.

METHODS The radiological and clinical records of 210 patients with ID-SAVSs were retrospectively reviewed, considering their localization, vascular architectonics, and correlation with the 5 histogenetic units of the spinal cord. Among these, 183 files with complete data allowed precise analysis of the ID-SAVSs.

RESULTS Among these 183 files (162 and 21 cases with single and multiple lesions, respectively), different entities were identified: 13 pial macro arteriovenous fistulas (MAVFs), 92 pial micro arteriovenous fistulas (mAVFs), 33 superficial pial niduses, and 69 intramedullary niduses. Thirteen sulcal shunts (either fistulas or niduses) were considered subtypes of pial lesions. Among the 21 multiple cases, 11 were monomyelomeric while 10 were multimyelomeric. Pial lesions, either fistulas or niduses, were dominantly vascularized by pial arteries (anterior or posterior depending on the localization of the shunt) and occasionally (except for MAVFs) by transmedullary arteries. Pial niduses occasionally extended into the funiculus by recruiting intrinsic veins or by extension of the nidus itself inside the white matter. Intramedullary niduses were always vascularized by both centrifugal and centripetal feeders, respectively, from sulcal arteries (SAs) and pial arteries. Sulcal lesions are pial lesions located within the ventral median sulcus and vascularized by SAs and veins. Single or multiple ID-SAVSs can be part of various syndromes such as hereditary hemorrhagic telangiectasia, Parkes-Weber, RASA1, CLOVES, and spinal arteriovenous metameric syndromes. Histogenetic analyses revealed a specific distribution of each ID-SAVS in the 5 histogenetic units of the spinal cord: intramedullary niduses were found almost equally from cervical to thoracic units, while MAVFs and mAVFs were mostly found from thoracic to postcrural ones. Pial niduses showed intermediate features between intramedullary and fistulous lesions and were mostly distributed from brachial to crural segments.

CONCLUSIONS Precise analysis of the anatomical disposition of ID-SAVSs in relation to functional histogenetic units allows a better understanding of these lesions and improved therapeutic management.

 

Multimodality Treatment of Conus Medullaris Arteriovenous Malformations

Neurosurgery 71:100–108, 2012 DOI: 10.1227/NEU.0b013e318256c042

Conus medullaris arteriovenous malformations (AVMs) are rare, challenging spinal vascular lesions that cause progressive debilitating myeloradiculopathy. Only sporadic reports of conus AVMs have been published.

OBJECTIVE: To better define the presentation, prognosis, and optimal treatment of these lesions, we present the first case series of conus AVMs, reflecting over 2 decades of experience with a multimodality endovascular and surgical approach.

METHODS: We retrospectively reviewed the charts of 16 patients with a conus AVM evaluated at our institution from 1989 to 2010. For each patient, the following clinical data were collected: age, sex, symptoms, angiographic findings, type of treatment, complications, degree of angiographic obliteration, recurrence at follow-up, and need for re-treatment. Ambulatory status, Frankel Grade, motor function, and bladder/bowel function were assessed before treatment, at discharge, and at last follow-up.

RESULTS: All 16 patients were treated. Eight (50%) patients underwent embolization followed by microsurgical resection, and 8 (50%) underwent microsurgical resection only. The rate of complete angiographic obliteration was 88%. At last follow-up (mean, 70 months), 43% of patients neurologically improved, 43% were stable, and 14% worsened in comparison with before treatment. During follow-up, 3 recurrences were detected, including the only 2 instances of long-term neurological decline. In the absence of recurrence, all patients ambulatory before treatment remained ambulatory at follow-up, whereas 75% of the initially nonambulatory patients regained the ability to walk.

CONCLUSION: Although conus AVMs are challenging to treat, excellent long-term outcomes are possible with a multimodality approach. Recurrence is associated with long-term neurological decline and calls for close follow-up.

The use of 3D computer graphics in the diagnosis and treatment of spinal vascular malformations

J Neurosurg Spine 15:654–659, 2011. DOI: 10.3171/2011.8.SPINE11155

Digital subtraction (DS) angiography is the gold standard for diagnosing spinal vascular malformations. Recently, multidetector-row spiral CT and contrast-enhanced MR angiography have been introduced as screening examinations before DS angiography. These methods, however, do not always determine the accurate location of an arteriovenous shunt because the resulting images lack information about the spinal cord or the dura mater.

Methods. Between April 2009 and December 2010, 13 patients underwent imaging evaluations for spinal vascular malformations at the authors’ university hospital. This group included 8 patients with spinal dural arteriovenous fistulas (AVFs), 3 with perimedullary AVFs, and 2 with intramedullary arteriovenous malformations. Using data from these patients, the authors attempted to develop 3D computer graphics (CG) based upon the fusion of 3D rotational angiography and postmyelographic CT. They subsequently verified the accuracy of this imaging method. Ten of these 13 patients underwent surgical treatment for their lesions (11 AVFs), and for these 11 lesions the authors compared the diagnoses obtained using 3D CG with those obtained using conventional DS angiography.

Results. In all 13 cases, 3D CG images of the spinal lesions were successfully developed using the patients’ actual data. Four (36%) of 11 AVFs were correctly identified using DS angiography, whereas 10 (91%) were correctly identified using 3D CG. Results from 3D CG of spinal AVFs corresponded well with operative findings, and 3D CG was significantly better than conventional DS angiography at predicting AVF location (p = 0.024, Fisher exact test).

Conclusions. To the authors’ knowledge, this is the first reported case series in which 3D CG of spinal vascular malformations was used to provide simultaneous, stereoscopic visualization of the spinal vascular system, spinal cord, dura mater, and bone. The 3D CG method provides precise visual images for the diagnosis and treatment of these lesions.