"And do no harm": Complications in interventional neuroradiology

Complications are an unfortunate reality in the field of interventional neuroradiology. While complications cannot be eliminated entirely, their occurrence and severity can be mitigated by the competency achieved through training, knowledge of cerebrovascular anatomy and pathology, and well-conceived and executed plans crafted in conjunction with a multidisciplinary team. Frequent communication among the team throughout the entire process of care is vital. In the ensuing chapter, an overview is provided of the most common complication types-nontarget embolization and hemorrhage-followed by practical considerations for their management. Finally, the chapter concludes with a brief consideration of the emotional management for the patient, their loved ones, and the involved practitioners.

Combined Embolization and Gamma Knife Radiosurgery for Cerebral Arteriovenous Malformations

In a study of 46 patients with cerebral arteriovenous malformations (AVMs) the value of combining embolization and gamma knife radiosurgery was assessed. In 35 patients with large grade III to V AVMs (Spetzler-Martin system) staged combined treatment was planned. In 11 patients, radiosurgery complemented embolization for a residual AVM. The number of embolization sessions ranged from 1 to 7 (median 2). Twenty-six patients needed multiple embolization sessions. In 28 patients the grade of AVMs decreased as a result of embolization. In 16 patients collateral feeding vessels developed after embolization which made delineation of the residual nidus difficult. The time lag between the last embolization and radiosurgery ranged from 1 to 24 months (median 4). Nineteen of 35 large grade III to V AVMs were possible to treat by radiosurgery following embolization. In the 46 patients complications occurred in 9 from embolization and in 2 from radiosurgery. Two patients had transient and 9 had permanent neurologic deficits. It is concluded that embolization facilitates radiosurgery for some large AVMs and therefore this combined treatment has a role in the management of AVMs.

Radiation Doses to Patients and Personnel Involved in Embolization of Intracerebral Arteriovenous Malformations

Radiation doses to patients and personnel were measured during 5 embolization procedures in 5 different patients. Thermoluminescent dosimeters were used to measure the absorbed doses in different points of the skin of patients as well as personnel. A transmission ionization chamber was used to determine the energy imparted in the patients. The effective dose equivalent HE during the procedures was estimated to be in the range of 6 to 43 mSv to the patients, 10 to 26 μSv to the radiologist in charge of the embolizations, 3 to 24 μSv to the assisting radiographer and 13 to 86 μSv to the nurse anesthetist. Radiation doses to the patients were considerable but the estimated risks from radiation were low compared to the risks of the arteriovenous malformation itself and the hazards of the embolization. The annual radiation doses to the personnel were well below established dose limits.

Late Follow-Up of Cyanoacrylate Usage in Cardiothoracic Surgery

In cardiovascular and thoracic surgery, troublesome bleeding and sternal dehiscence can be life-threatening if not managed appropriately. We used commercially available cyanoacrylate adhesive 21 times in 20 sporadic patients for the management of 6 different problems: sternal gluing in 7 cases; anastomotic line reinforcement and bleeding control with a glued Teflon or pericardial patch in 6; right ventricular or superior vena caval patch repair in 5; and 1 case each of left ventricular apical glued Teflon felt, arterial wall reinforcement, and control of air leakage after lung surgery. The mean age of the patients was 55.7 ± 12.5 years, ranging from 34 to 71 years. Successful results were obtained in 18 patients and 17 were alive on follow-up at 7.7 ± 5.5 months (range, 2 to 16 months). We used two different commercial brands of adhesive but obtained good results with only one of these preparations. Although commercially available cyanoacrylate is a new adjunct to cardiac surgery with documented safety and lifesaving results at negligible cost, the appropriate polymer for best results needs to be defined.

A method to screen and evaluate tissue adhesives for joint repair applications

BACKGROUND

Tissue adhesives are useful means for various medical procedures. Since varying requirements cause that a single adhesive cannot meet all needs, bond strength testing remains one of the key applications used to screen for new products and study the influence of experimental variables. This study was conducted to develop an easy to use method to screen and evaluate tissue adhesives for tissue engineering applications.

METHOD

Tissue grips were designed to facilitate the reproducible production of substrate tissue and adhesive strength measurements in universal testing machines. Porcine femoral condyles were used to generate osteochondral test tissue cylinders (substrates) of different shapes. Viability of substrates was tested using PI/FDA staining. Self-bonding properties were determined to examine reusability of substrates (n = 3). Serial measurements (n = 5) in different operation modes (OM) were performed to analyze the bonding strength of tissue adhesives in bone (OM-1) and cartilage tissue either in isolation (OM-2) or under specific requirements in joint repair such as filling cartilage defects with clinical applied fibrin/PLGA-cell-transplants (OM-3) or tissues (OM-4). The efficiency of the method was determined on the basis of adhesive properties of fibrin glue for different assembly times (30 s, 60 s). Seven randomly generated collagen formulations were analyzed to examine the potential of method to identify new tissue adhesives.

RESULTS

Viability analysis of test tissue cylinders revealed vital cells (>80%) in cartilage components even 48 h post preparation. Reuse (n = 10) of test substrate did not significantly change adhesive characteristics. Adhesive strength of fibrin varied in different test settings (OM-1: 7.1 kPa, OM-2: 2.6 kPa, OM-3: 32.7 kPa, OM-4: 30.1 kPa) and was increasing with assembly time on average (2.4-fold). The screening of the different collagen formulations revealed a substance with significant higher adhesive strength on cartilage (14.8 kPa) and bone tissue (11.8 kPa) compared to fibrin and also considerable adhesive properties when filling defects with cartilage tissue (23.2 kPa).

CONCLUSION

The method confirmed adhesive properties of fibrin and demonstrated the dependence of adhesive properties and applied settings. Furthermore the method was suitable to screen for potential adhesives and to identify a promising candidate for cartilage and bone applications. The method can offer simple, replicable and efficient evaluation of adhesive properties in ex vivo specimens and may be a useful supplement to existing methods in clinical relevant settings.

Tissue reactions induced by different embolising agents in cerebral arteriovenous malformations: a histopathological follow-up

AIMS

Comparative histopathological analysis was performed in 47 incompletely embolised and resected cerebral arteriovenous malformations (AVMs).

METHODS

Thirty-three AVMs were embolised with n-butyl-cyanoacrylate (NBCA), four with iso-butyl-cyanoacrylate (IBCA), seven with polyvinyl alcohol particles (PVA), one with a fibrin mixture, one with silicon pellets, and one with microcatheter balloons. Maximum exposure time (MET) of the embolising agent (interval between embolisation and surgery) ranged from <24 hours to 80 months. All AVMs were investigated regarding angionecrosis, angiofibrosis, acute inflammation, chronic inflammation, foreign-body reactions, vascular calcification, blood admixture to embolising cast, and capillary recanalisation within the AVMs. These parameters were correlated with MET, comparing different embolising agents, age, and sex.

RESULTS

A typical sequence of events depending on MET is observed in all embolised AVMs: acute inflammation with mural angionecrosis is soon replaced by prominent chronic granulomatous vasculitis, which remains stable and is detectable for a very long time, even in AVMs with a MET of more than 6 years.

CONCLUSION

Capillary recanalisation is always present in incompletely embolised AVMs, detectable after 3 months of MET, irrespective of the embolising agent used. Age and sex does not influence pattern and time course of tissue lesions and recanalisation in incompletely embolised AVMs.

Trapped Microcatheter from Vessel Spasm: Safe Removal after Double Microcatheter Technique and Local Papaverine Infusion

In a child undergoing combined transarterial and direct percutaneous puncture embolization of an extensive and complex facial arteriovenous malformation, severe arterial spasm fixed a flow-directed microcatheter in an ethmoidal branch of the left ophthalmic artery. Multiple traction attempts failed to remove the microcatheter. After catheterization of the distal, post central retinal artery part of the same ophthalmic artery, with a second flow-directed microcatheter and following intraarterial papaverine injection through this second microcatheter, the fixed microcatheter could be removed without complication. This case demonstrates a technique that can be attempted before deciding to leave the microcatheter in the patient or to remove it surgically.

Glued Catheters during Embolisation of Brain AVMs with Acrylic Glue

SUMMARY

We evaluated the frequency and the side effects associated with gluing a piece of microcatheter in the feeder during embolisation of brain AVMs with acrylic glue. A retrospective analysis of 233 brain AVMs embolised with acrylic glue over a 15 year period has shown that 29 microcatheters were glued into the feeder. This represents 936 superselective catheterizations of different feeders followed by injection of glue. There was no side effect in 27 cases. Eight cases were operated upon a few hours or days after the complication occurred. The piece of tubing was removed in six cases. The reason for early surgery was the fear of extensive thrombosis of a major trunk (MCA or BA) or taking advantage of the catheter being still free in the cerebral vessel. In one case of temporal AVM, a Magic 1.5F coiled up into the distal basilar and PCA. In one case of left parietotemporal AVM, surgery was done one month after having glued a piece of tubing into the left MeA without side effect. The patient became hemiplegic and aphasic two hours after surgery. The thrombosed left MeA was reopened with Urokinase. The patient recovered with minor residual aphasia. The risk of side effects increases with the use of the Magic 1.5F that coils up into the vessel more easily than the Magic 1.8F. Leaving a piece of Magic catheter in the feeder to a brainAVM usually has no side effect. When there is a risk of thrombosis of a major trunk (MCA, BA) or when surgical resection is indicated, surgery should be done as soon as possibile because it is usually possible and easy to retrieve the piece of tubing from the intracranial circulation. The frequency of this complication has decreased since we starded using more diluted acrylic glue.

Fixation of the craniofacial skeleton with butyl-2-cyanoacrylate and its effects on histotoxicity and healing

Butyl-2-cyanoacrylate is an easily applied, biocompatible, bioresorbable polymer glue that provides an alternative to conventional rigid fixation techniques. Our aim was to determine if cyanoacrylate fixation of the bone flap in a rabbit craniotomy model provides the healing and strength afforded by plate and screw fixation. We also investigated the inflammatory responses of adjacent tissues including the scalp, cranium, and brain. A unilateral parietal bone flap was elevated in 33 adult New Zealand rabbits. The bone was fixed in position with cyanoacrylate (n = 13), fixed with a microplate and screws (n = 14), or was replaced without fixation (sham-control, n = 6). Normal scar formation and no residual polymer were found in scalp specimens. Neuropathologic analysis identified the presence of residual polymer on the surface of 2 of the 13 rabbit brains. Histopathologic analysis of the bone flap-to-skull interface revealed no difference in the degree but rather in the quality of inflammation and healing between the plate and screw and polymer fixation groups. Microdensitometric analysis of the bone gap revealed nearly equivalent bone density in the cyanoacrylate and plated groups, tending to less density in the sham group (p = 0.11 and 0.09, respectively). An additional study focusing on neurotoxicity was performed in 20 adult rabbits with 3-week and 11-week recovery periods and similarly found the absence of a marked inflammatory response to the polymer. In conclusion, bone healing and soft-tissue inflammation were comparable between cyanoacrylate and plate and screw fixation groups. Although butyl-2-cyanoacrylate glue fixation may provide a reasonable alternative to hardware fixation, further investigations are necessary to identify its ideal utilization.

Butyl-2-cyanoacrylate fixation of mandibular osteotomies

Butyl-2-cyanoacrylate is an easily applied, bioresorbable, noninfective glue that may provide an alternative to conventional craniofacial fixation techniques. Recent studies have demonstrated that the healing and strength of glue fixation of bone fragments in the craniofacial skeleton is equivalent to that of plate and screw fixation. We sought to determine if this glue could also provide strength and healing in a more stressed environment, that of the mandible. Fourteen New Zealand White rabbits underwent mandibular osteotomies at the angle. The osteotomy was fixed with either a microplate (n = 4) or glue (n = 10). Mandibles were assessed 10 weeks postoperatively and classified according to bone healing, condylar morphology, and dental morphology. Callus and nonunion were more prevalent in the glued group, whereas condylar resorption was similar in both experimental groups. Despite the poor bony healing in the glued group, the teeth did not decay but modified their standard form to meet the demands of the anatomic deformity. Butyl-2-cyanoacrylate does not offer the biomechanical stability afforded by plates and screws in bone subject to large forces.

Embolization of cerebral arteriovenous malformations: Part I--Technique, morphology, and complications

OBJECTIVE

The aim of this two-part study is to give a full account of all patients referred for embolization of arteriovenous malformations (AVMs) from 1987 to 1993. This article (Part I of II) presents the patient study, including angiographic features and their relation to the immediate outcome of embolization.

METHODS

Of the 192 patients referred, 150 were subsequently treated. Most patients were referred by neurosurgeons, and 85% of the AVMs were Spetzler-Martin Grade > or = 3. We have accounted for the 42 patients who did not undergo embolization.

RESULTS

Occlusion from embolization alone (total embolization) was obtained in 13% of patients. Full treatment (total embolization or embolization and then stereotactic radiation or surgery) was achieved in two-thirds of all patients (n = 100, 66%), and combined treatment with stereotactic gamma radiation was the most important part of the treatment strategy. The procedural mortality was 1.3%. The total incidence of complications after embolization was high (40%), but only 6.7% of cases were labeled severe. Of all angiographic features that were considered, large size and the presence of deep feeders were predictors of failure to achieve full treatment. Thirty-four patients with AVMs < 8 cc were included in the study. These could have been irradiated as the sole treatment. In this group of small AVMs, the results of embolization were far better than in the whole group. Fourteen of the AVMs had volumes of < 4 cc, and 10 of these (71%) were totally embolized. One patient had a hemianopsia. Among AVMs 4 to 8 cc in volume (n = 20), the total embolization rate was 15%, the full treatment rate in combination with gamma treatment was 75%, and 10% of the patients were operated on after embolization. Severe complications occurred in 15% of patients, but no complications occurred after November 1990.

CONCLUSION

In a series of AVMs, most of which were regarded as unsuitable for surgical excision, two-thirds were reduced to a size suitable for gamma knife treatment or totally occluded by embolization alone. The total complication rate was high, but the combined rate of death and complications affecting lifestyle was 8.0%, equal to approximately 3.2 years of natural history.

Embolization of cerebral arteriovenous malformations: Part II--Aspects of complications and late outcome

OBJECTIVE

From 1987 through 1993, we performed embolizations on 150 patients with cerebral arteriovenous malformations (AVMs) at Sahlgrenska University Hospital. The patients ranged in age from 5 to 70 years (35.5 +/- 14.8 yr, mean +/- standard deviation) and were selected by neurosurgeons in Scandinavia. We analyzed the risk of complications and late outcome to have a better basis for the decision to perform embolization.

METHODS

The follow-up was a personal clinical examination of all surviving patients by a neurologist. Files for all patients were also studied.

RESULTS

In 34 patients, the AVMs were eliminated by embolization alone (20 patients) or by supplementary surgery (14 patients). In 66 patients, the AVMs were embolized to a size suitable for supplementary stereotactic radiation. The clinical course was stable for those 100 patients. Another group of 50 patients who had undergone embolization was only partially treated, and as a group, those patients had less favorable outcomes. The manifestations or symptoms leading to diagnosis were in concordance with other studies. Headache and epilepsy showed a positive response to treatment in patients whose AVMs had been eliminated as well as in those who received only partial treatment. A history of cerebral bleeding did not influence the prognosis of recurrent bleeding. Conversely, AVMs with feeder or nidus aneurysms were related to an increased risk of bleeding. If there was a history of bleeding in a patient with large, partially treated AVMs, the prognosis for survival was diminished.

CONCLUSION

The indication for treatment increases with the occurrence of AVMs with associated aneurysms. For patients with large AVMs, a history of bleeding justifies a more aggressive approach to treatment. The reduced risk of complications during the last years of the study also increases the indication for embolization.

Treatment of brain arteriovenous malformations by embolization and radiosurgery

Embolization was used to reduce the size of brain arteriovenous malformations (AVMs) prior to radiosurgical treatment in 125 patients who were poor surgical candidates or had refused surgery. Of these patients, 81% had suffered hemorrhage, and 22.4% had undergone treatment at another institution. According to the Spetzler-Martin scale, the AVMs were Grade II in 9.6%, Grade III in 31.2%, Grade IV in 30.4%, and Grades V to VI in 28.8% of the cases. Most embolizations were performed using cyanoacrylate delivered by flow-guided microcatheters. Radiosurgery was performed using a linear accelerator in 62 patients treated by the authors, and 34 patients were treated at other institutions using various methods. Embolization produced total occlusion in 11.2% of AVMs and reduced 76% of AVMs enough to allow radiosurgery. Radiosurgery produced total occlusion in 65% of the partially embolized AVMs (79% when the residual nidus was < 2 cm in diameter). Embolizations resulted in a mortality rate of 1.6% and a morbidity rate of 12.8%. No complications were associated with radiosurgery. The hemorrhage rate for partially embolized AVMs was 3% per year. No patient with a completely occluded AVM experienced rehemorrhage. Angiographic follow-up review of AVMs embolized with cyanoacrylate demonstrated a 11.8% revascularization rate, occurring within 1 year. It is concluded that after partial embolization with cyanoacrylate, the risk of hemorrhage from the residual nidus is comparable to the natural history of AVMs and that the residual nidus can be irradiated with results almost as good as for a native AVM of the same size.

Cure, morbidity, and mortality associated with embolization of brain arteriovenous malformations: a review of 1246 patients in 32 series over a 35-year period

Published reports of cure, morbidity, and mortality associated with the embolization of 1246 brain arteriovenous malformations during the last 35 years were reviewed. Embolization resulted in cure in 5% of arteriovenous malformations. The cure rates of embolization were 4% in reports of 708 patients published before 1990 and 5% in reports of 538 patients published since 1990 (P = not significant). Temporary morbidity from embolization was 10%, and permanent morbidity was 8%. Permanent morbidity was 9% before 1990 and 8% since 1990 (P = not significant). Death after embolization of brain arteriovenous malformations occurred in 1% of patients. Mortality associated with the embolization was 2% before 1990 and 1% since 1990 (P = not significant). Long-term morbidity associated with the use of neurotoxic embolization materials is worrisome but has never been proven.

Persistent feeding arteries to angiographically completely embolized arteriovenous malformation demonstrated by intraoperative color-flow Doppler testing: report of two cases

Two cases of arteriovenous malformation (AVM) treated preoperatively by endovascular embolization that appeared to be completely occluded after embolization are presented. Seven and 12 days later, respectively, these patients underwent resection of their AVM. At the time of surgery, intraoperative color-flow Doppler studies revealed persistent feeding arteries to an active residual nidus of the AVM. The significance of this finding is presented in light of previous published literature.

Superselective angiography, embolisation and surgery in treatment of arteriovenous malformations of the brain

We prospectively evaluated a diagnostic and therapeutic procedure combining superselective angiography, endovascular embolisation and surgery in arteriovenous malformations (AVM) of the brain. Our aim was to achieve the best possible result exposing the patients to the lowest possible risk. During a 3 year period 48 patients were studied, of whom 22 (46%) were treated by incomplete preoperative embolisation and subsequent complete surgical removal of the AVM. All angiography and embolisations were performed with the Tracker catheter system using polyvinyl alcohol particles and/or platinum fibre coils. The other 26 patients were treated as follows: incomplete embolisation in 11 (23%), complete embolisation in 2 (4%), angiography and surgery in 3 (6%) and combined embolisation and radiation in 7 (15%); 3 patients were excluded from any therapy after superselective angiography. The total number of acute complications and permanent sequelae were 8 (17%) and 3 (6%) respectively. We concluded that superselective cerebral angiography, a relatively safe procedure, should play an important role in deciding treatment strategies for AVMs of the brain. The risks of combined embolisation and surgery are probably lower than those of either alone. In a few cases surgery or embolisation alone carries an unequivocally lower risk, and combined therapy is not justifiable.

Embolization of intracranial arteriovenous malformations and fistulas with polyvinyl alcohol particles and platinum fibre coils

In order to reduce the recanalization rate of arteriovenous malformations and multiple dural arteriovenous fistulas, embolization was carried out with polyvinyl alcohol (PVA) particles combined with platinum fibre coils in 20 patients. The malformation was occluded more effectively than by PVA alone. Distal deposition of the emboli was obtained by improved steerable catheters (Tracker-18-unibody) and guidewires. The complication rate was lower than usually reported from studies using glue as embolic agent. It was concluded that the combination of PVA and fibre coils enhances the safety and effectiveness of embolization therapy and reduces the frequency of recanalization of intracranial AVMs.