Brainstem Cavernous Malformations: Surgical Indications Based on Natural History and Surgical Outcomes

Intraoperative Mapping of the Sensory Root of the Trigeminal Nerve in Patients with Pontocerebellar Angle Pathology

OBJECTIVE

The aim of the present study was to determine the position of the 3 sensory branches of the trigeminal nerve in the preganglionic tract using intraoperative neurophysiological mapping.

METHODS

We included consecutive adult patients who underwent neurosurgical treatment of cerebellopontine angle lesions. The trigeminal nerve was antidromically stimulated at 3 sites along its circumference with different stimulus intensities at a distance of ≤1 cm from the brainstem. The sensory nerve action potentials (SNAPs) were recorded from each main trigeminal branch (V1 [ophthalmic branch], V2 [maxillary branch], and V3 [mandibular branch]).

RESULTS

We analyzed 13 patients. The stimulation points at which we obtained the greatest number of congruous and exclusive SNAPs (SNAPs only on the stimulated branch) was the stimulation point for V3 (20.7%). The stimulation intensity at which we obtained the highest number of congruent and exclusive SNAPs with the stimulated branch was 0.5 mA.

CONCLUSIONS

Using our recording conditions, trigeminal stimulation is a reliable technique for mapping the V3 and V1 branches using an intensity not exceeding 0.5. However, reliable identification of the fibers of V2 is more difficult. Stimulation of the trigeminal nerve can be a reliable technique to identify the V3 and V1 branches if rhizotomy of these branches is necessary.

Cerebral cavernous malformation: Management, outcomes, and surveillance strategies - A single centre retrospective cohort study

BACKGROUND

Cerebral cavernous malformations (CCM) may undergo a period of clinical and/or radiographical surveillance that precedes or follows definitive treatment. There are no international guidelines on the optimal surveillance strategy. This study describes the surveillance strategies at our centre and explore the related clinical outcomes.

METHODS

We performed a retrospective study of adult patients with CCMs referred to a neurovascular service over an 8-year period, to determine the frequency and type of surveillance, intervention, and explore the associated outcomes. We report our findings adhering to STROBE guidelines.

RESULTS

133 patients (Male:Female 73:60; men age 42 years; range 12-82) were included. CCMs were identified in patients first presenting with symptomatic intracerebral haemorrhage (42.11%); headache, focal neurological deficit, or seizure without haemorrhage (41.35%); or, as an incidental finding (16.54%). The most common CCM location was supratentorial (59.40%), followed by brain stem (21.80%), cerebellum (10.53%) and basal ganglia (6.02%). Of the 133 patients, 77 patients (57.89%) were managed conservatively, 49 patients (36.84%) were managed by surgical resection alone, and seven patients (5.26%) were managed with stereotactic radiosurgery (SRS). Patients follow-up had a mean duration of 65.94 months, and varied widely (SD = 52.59; range 0-265), for a total of 730.83 person-years of follow up. During surveillance, 16 patients suffered an ICH equating to a bleeding rate of 2.19 per 100 patient years. CCMs that increased in size had a higher bleeding rate (p = 8.58 ×10^-4). There were 8 (6.02%) cases where routine clinic review or MRI resulted in a change in management.

CONCLUSIONS

Our single centre retrospective study supports existing literature relating to presentation and sequalae of CCM, with an increase in CCM size being associated with higher rates of detected bleeding. There remains heterogeneity, even within a single centre, on the frequency and modality of surveillance. Further, there are no international guidelines or high-quality data that recommends the optimal duration and frequency of surveillance, and its effect on clinical outcomes. This is a future research direction.

Cavernous malformations

Cavernous malformations are relatively common intracerebral malformations of which we only became properly aware after the introduction of MRI. They may be sporadic or familial. Familial CMs may be multiple and new lesions appear over time requiring intermittent MR control. Many sporadic CMs have no symptoms. The commonest location is in the supratentorial cerebral parenchyma presenting with epilepsy. The best treatment is microsurgery. A small proportion are in the brainstem and may rebleed and even be lethal. Treatment includes microsurgery and radiosurgery. Microsurgery cures the patient but has substantial problems with complications, deterioration and partial removal. Radiosurgery has taken time to demonstrate that it can over 2 years substantially reduce the risk of rebleeds without the risks of microsurgery. Both methods have a part to play in the treatment.

The BSCM score: a guideline for surgical decision-making for brainstem cavernous malformations

Microsurgical resection of brainstem cavernous malformations (BSCMs) can be performed today with acceptable morbidity and mortality. However, in this highly eloquent location, the indication for surgery remains challenging. We aimed to elaborate a score system that may help clinicians with their choice of treatment in patients with BSCMs in this study. A single-center series of 88 consecutive BSCMs patients with 272 follow-up visits were included in this study. Univariable and multivariable generalized estimating equations (GEE) were constructed to identify the association of variables with treatment decisions. A score scale assigned points for variables that significantly contributed to surgical decision-making. Surgical treatment was recommended in 37 instances, while conservative treatment was proposed in 235 instances. The mean follow-up duration was 50.4 months, and the mean age at decision-making was 45.9 years. The mean BSCMs size was 14.3 ml. In the multivariable GEE model, patient age, lesion size, hemorrhagic event(s), mRS, and axial location were identified as significant factors for determining treatment options. With this proposed score scale (grades 0–XII), non-surgery was the first option at grades 0–III. The crossover point between surgery and non-surgery recommendations lay between grades V and VI while surgical treatment was found in favor at grades VII–X. In conclusion, the proposed BSCM operating score is a clinician-friendly tool, which may help neurosurgeons decide on the treatment for patients with BSCMs.

Natural History of Brainstem Cavernous Malformations: On the Variation in Hemorrhage Rates

BACKGROUND

Hemorrhage rates of conservatively managed brainstem cavernous malformations (BSCMs) vary widely in the literature. We aimed to elucidate the reason for the variation and to add the results of our experience of BSCMs management over the past decade.

METHODS

We performed a review of consecutive patients with BSCMs referred to our department in the period 2006-2018. A hemorrhagic event was defined as a radiographically verified intralesional and extralesional hemorrhage. Both retrospective and prospective hemorrhage rates were calculated based on the patient age in years, counted either from birth or from the time of initial presentation until the last contact (or until surgical resection). In addition, we retrieved and reviewed publications with a clear definition of hemorrhagic event and a detailed description of BSCM hemorrhage rate.

RESULTS

In total, 118 patients with BSCMs were reviewed, and 78 patients (mean age on admission 45.9 years) were included in the final analysis. The retrospective and prospective hemorrhage rates were 1.9% (95% confidence interval 1.6%-2.3%) per year and 11.9% (95% confidence interval 7.5%-17.8%), respectively. The retrospective hemorrhage rate in the literature review ranged from 1.9% to 6.8% per year with a median value of 3.8%, whereas the prospective hemorrhage rate ranged between 4.1% and 21.5%, with a median value of 10.2%.

CONCLUSIONS

The reported hemorrhage rates are calculated in 2 different ways. In our patient cohort, both the retrospective and prospective hemorrhage rates were in accordance with those in the literature. The long-term hemorrhage rate lies between the prospective and retrospective rate.

Occipital posterior interhemispheric supratentorial approach for resection of midbrain cavernous malformation

Approaches to the pineal region are various, and each has its advantages and disadvantages. The authors present a case of a 50-year-old woman who presented with progressive hemiparesis and vertical gaze palsy; she was diagnosed with a midbrain cavernous malformation. The patient underwent an occipital posterior interhemispheric supratentorial transpineal approach with gross-total resection. On long-term follow-up, her symptoms significantly improved. The authors review the regional anatomy and present the operative video. They also discuss the various approaches with their indications, advantages, and disadvantages.

The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2133.

Sub-telo-velo-tonsillar approach to resect dorsal pons cavernoma through fourth ventricular floor opening: how I do it

BACKGROUND

Dorsal pons cavernoma can be approached through telo-velar approach instead of transvermian approach, with lower risk of neurological deficits since it uses natural clefts to reach the floor of the fourth ventricle.

MATERIALS AND METHODS

We present our surgical technique for telo-velar approach to address pathologies of the dorsal pons, assisted by neuronavigation and neuromonitoring. This surgical technique is illustrated by a surgical video of a dorsal pons cavernoma.

CONCLUSION

Dorsal pons cavernomas can be reached through telo-velar approach after suboccipital midline craniotomy. The accurate patient positioning, cisternal dissection, and neuromonitoring use are mandatory to avoid neural injuries and identify the safe entry points into the brainstem.

How I do it: Subtemporal transtentorial approach for cavernous malformation of the pons

BACKGROUND

Removal of a pontine cavernous malformation requires sufficient exposure since any restriction on surgical freedom may lead to suboptimal visualization of the lesion, injury to the brainstem, and neurological catastrophe.

METHODS

We describe and demonstrate the subtemporal transtentorial approach to a cavernous malformation of the upper pons, with emphasis on adequate surgical exposure while avoiding the need for extensive bone removal of the skull base.

CONCLUSIONS

The meticulous technique is paramount to the successful removal of any brainstem cavernous malformation. Along with the surgical exposure, delicate handling of the malformation is demonstrated in the accompanying operative video.

An international call for a new grading system for cerebral and cerebellar cavernomas

Surgical indications for cerebral cavernous malformations remain significantly center- and surgeon-dependent. Available grading systems are potentially limited, as they do not include epileptological and radiological data. A novel grading system is proposed for supratentorial and cerebellar cavernomas: it considers neuroradiological features (bleeding, increase in size), neurological status (focal deficits and seizures), location of the lesion and age of the patient. The score ranges from -1 to 10; furthermore, surgery should be considered when a score of 4 or higher is present. Based on neuroradiological characteristics, 0 points are assigned if the CCM is stable in size at different neuroradiological controls, 1 point if there is an increase in volume during follow-up, 2 points if intra- or extra-lesional bleeding <1 cm is present and 3 points if the CCM produced a hematoma >1 cm. Regarding focal neurological deficits, 0 points are assigned if absent and 2 points if present. For seizures, 0 points are assigned if absent, 1 point if present, but controlled by medications, and 2 points if drug resistant. We considered the site of the CCM, and in case of deep-seated lesions in a critical area (basal ganglia, thalamus) 1 point (-1) is subtracted, while for subcortical or deep cerebellar lesions 0 points are assigned, for CCMs in a cortical critical area 1 point is assigned and in case of lesions in cortical not in critical area or superficial cerebellar area, 2 points are assigned. As far as age is concerned, 0 points are assigned for patients older than 50 years and 1 point for patients younger than 50. In conclusion, a novel grading for surgical decision making in cerebral cavernomas, based on the experience of selected neurosurgeons, basic scientists, and patients, is suggested with the aim of further improving and standardizing the treatment of CCMs. The aim of this paper was also to call for both retrospective and prospective multicenter studies with the aim of testing the efficacy of the grading system in different centers.

Endoscopic Endonasal Resection of a Pontine Brainstem Cavernoma

Surgical treatment of brainstem cavernoma is controversial.¹ With modern surgical technique, safe and complete removal of selected brainstem cavernoma is possible.² The choice of optimal corridor must consider various factors, including eloquent structures of the brainstem, cavernoma shape and location, as well as the presence of an exophytic portion to the lesion.^3,4 The endoscopic endonasal approach, with its refinement through the last decade, could offer an optimal corridor for the removal of ventral brainstem cavernomas. This video exemplifies the key surgical steps, advantages of the technique, and relevant anatomy for the endoscopic endonasal removal of a ventrally exophytic pontine cavernoma.

Ruptured pontine cavernomas in infants: a report of two cases

BACKGROUND

Cavernous malformations (CMs) are either congenital or acquired vascular lesions comprised of sinusoid spaces filled with either blood or its breakdown products. They possess a relatively reduced risk of hemorrhage, yet placement within the posterior fossa and especially the brainstem heightens their likelihood to rupture, making them a likely cause of permanent and debilitating neurological deficit, as well as a veritable surgical challenge. Although the incidence of rupture varies with age among reported case series, it is undoubtable that the severity of this occurrence is the highest while the brain is as its most vulnerable period, i.e. during infancy.

CASE PRESENTATIONS

We present two patients, both female, 6.5- and 5-months-old respectively, who presented with brainstem hemorrhage from CM. They suffered from a sudden onset of hemiparesis and were subjected to surgical removal of their lesions and resulting hematomas. Both patients were discharged in a favorable neurological status and are currently alive and in good health.

CONCLUSION

Microsurgical treatment of brainstem CMs in infants is not only possible with minimal deficit, but also advisable if the lesions are symptomatic. Nevertheless, this requires substantial patience and experience to prevent significant loss of blood and injury to the structures of the posterior fossa. We argue that the safest method to prevent further damage from brainstem CM rebleed is to remove these lesions shortly after the initial hemorrhage.

Microsurgery vs. Gamma Knife Radiosurgery for the Treatment of Brainstem Cavernous Malformations: A Systematic Review and Meta-Analysis

Background: Brainstem cavernous malformations (BSCMs) are a subset of cerebral cavernous malformations with precarious locations and potentially devastating clinical courses. The effects and outcomes of treating BSCMs by microsurgery or gamma knife radiosurgery (GKRS) vary across studies.

Methods: We searched the Medline, Web of Science, The Cochrane Library, PubMed, and China Biology Medicine disc databases for original articles published in peer-reviewed journals of cohort studies reporting on 20 or more patients of any age with BSCMs with at least 80% completeness of follow-up.

Results: We included 43 cohorts involving 2,492 patients. Both microsurgery (RR = 0.04, 95% CI 0.01–0.16, P < 0.01) and GKRS (RR = 0.11, 95% CI 0.08–0.16, P < 0.01) demonstrated great efficacy in reducing the rehemorrhage rate after treatment for BSCMs. The incidence rates of composite outcomes were 19.8 (95% CI 16.8–22.8) and 15.7 (95% CI 11.7–19.6) after neurosurgery and radiosurgery, respectively. In addition, we found statistically significant differences in the median numbers of patients between neurosurgical and radiosurgical cohorts in terms of symptomatic intracranial hemorrhage (ICH; neurosurgical cohorts: median 0, range 0–33; radiosurgical cohorts: median 4, range 1–14; P < 0.05) and persistent focal neurological deficit (FND; neurosurgical cohorts: median 5, range 0–140; radiosurgical cohorts: median 1, range 0–3; P < 0.05).

Conclusions: The reported effects of treating BSCMs by microsurgery or GKRS are favorable for reducing recurrent hemorrhage from BSCMs. Patients in the neurosurgery cohort had a lower incidence of symptomatic ICH, while patients in the radiosurgical cohort had a lower incidence of persistent FND.

Imaging characteristics of Intrasellar cavernous hemangioma: A case report

RATIONALE

Intrasellar cavernous hemangiomas (ICHs) are rare vascular lesions that arise in the sellar region. ICHs are usually misdiagnosed and treated as pituitary adenomas. Therefore, a preoperative diagnosis is particularly important, especially when the goal is complete resection.

PATIENT CONCERNS

A 55-year-old woman presented with a 1-month history of intermittent dizziness. Magnetic resonance imaging (MRI) revealed a well-demarcated abnormal ellipsoid signal in the sellar region (size: 2.7 cm × 1.7 cm), with a mulberry-like enhancement after gadolinium injection. Computed tomography revealed an intrasellar mass without calcification that extended into the left cavernous sinus and was faintly contrast-enhanced. Angiography revealed a tumor with mildly delayed staining fed by the C5 segment of the right internal carotid artery.

DIAGNOSIS

An intrasellar cavernous hemangioma based on neuroradiological examinations.

INTERVENTIONS

The patient underwent surgery with an endoscopic endonasal transsphenoidal approach to debulk the lesion and obtain tissue for the pathological diagnosis.

OUTCOMES

Blood spurting was observed after puncture, and the capsule was stained blue. Lesion removal was stopped, and the patient underwent gamma knife surgery 1 week later. She remained in good condition during the follow-up.

LESSONS

Sponge-like or mulberry-like lesions can be identified on MRI after gadolinium injection and can facilitate a preoperative diagnosis of ICH. Currently, surgical debulking with cranial nerve decompression during the acute stage and subsequent gamma knife radiosurgery are considered to be a safe and effective treatment.

[Electroconvulsive therapy in a female patient with a cavernous malformation in the medulla oblongata]

The implementation of ECT treatment should not be ruled out in principle even if there is a cavernoma of the medulla oblongata with previous bleeding, but it requires appropriate conditions such as neurosurgical consultation, strict blood pressure monitoring and special information from the patient.

Microsurgical Resection of a Middle Cerebellar Peduncle Cavernous Malformation: 3-Dimensional Operative Video

Brainstem cavernous malformations are frequently surrounded by vital structures, which often makes surgical treatment a challenging task even to the most skilled surgeon. Accordingly, microsurgical excision is preferably offered to symptomatic patients and superficial lesions.1-3 We present the case of a 41-yr-old male presenting with progressive dizziness and diplopia. Neurological examination showed horizontal nystagmus, dysmetria, and unbalance. Preoperative magnetic resonance imaging (MRI) suggested a cavernous malformation in the right middle cerebellar peduncle. A telovelar approach was employed with the guidance of intraoperative neurophysiological monitoring. An exophytic lesion was identified in the right middle cerebellar peduncle and a clear cleavage plane was obtained allowing circumferential dissection around the capsule. The lesion was removed en bloc. Postoperative MRI confirmed a complete excision of the malformation. The patient presented an improvement in his initial symptoms, with no new neurological deficit. Cavernous malformations related with the fourth ventricle can be successfully resected through a telovelar approach in select cases, especially when exophytic, where the surgeon might take advantage of the path created by the lesion. Informed consent was obtained from the patient for the procedure and publication of this operative video. Anatomic images were a courtesy of the Rhoton Collection, American Association of Neurological Surgeons (AANS)/Neurosurgical Research and Education Foundation (NREF).

[«Cavernous angiomas» of the brainstem. Clinical manifestations, diagnosis and treatment results]

Introduction

In the current literature, brainstem hematomas and various types of vascular micromalformations are combined into the one group of diseases under the general name «cavernous angioma» (CA). This approach does not make it possible to accurately determine the indications for surgery and predict postoperative outcomes.

Objective

To analyze our own experience in the diagnosis and treatment of patients with the brainstem CA.

Material and methods

There were 515 patients with CA of the brainstem (surgery - 322, conservative treatment - 193 patients) with a follow-up period of more than 5 years. Follow-up survey implied neurological examination, analysis of Karnofsky score, MRI and CT data.

Results

We identified two main groups of patients after comparison of MRI data, intraoperative findings and biopsy data: group 1 - hematomas (191 patients, 59%), group 2 - CA (131 patients, 41%). Each group was characterized by own clinical and radiological features. Postoperative outcomes depended on the disease. Debridement of hematoma ensured early postoperative improvement in 63% of patients, no changes in 21% of cases and impairment in 16% of patients. Less favorable results were observed in patients with CA and no signs of hemorrhage. Clinical impairment occurred in 73% of cases, improvement - only in 5% of patients. The most significant regression of neurological symptoms in long-term postoperative period was observed in patients with hematomas (92% of patients). These ones noted much better clinical state compared with preoperative condition.

Conclusions

The type of brain lesion is an important predictor to determine treatment approach. Postoperative outcomes differ significantly in patients with the brainstem hematoma and CA.

Transmastoid presigmoid retrolabyrinthine approach for removal of pontine cavernous malformation: how I do it

BACKGROUND

Bleeding of brainstem cavernous malformations (BSCM) cause high morbidity and should be treated surgically whenever possible.

METHOD

We present a 56-year-old man, who was diagnosed with a BSCM at right pons, which caused functional impairments of dorsal column, spinothalamic tract, cochlear nucleus, and middle cerebellar peduncle. A transmastoid presigmoid retorlabyrinthine approach via the lateral pontine zone (LPZ), with an assistance of imaging guidance and intraoperative neurophysiological monitoring, was performed to completely resect the BSCM. The patient recovered despite a transient worsening of cerebellar sign and hemiparesthesia for 1 week, without surgical complications.

CONCLUSIONS

A transmastoid presigmoid retrolabyrinthine approach through LPZ is safe and effective for lateral pontine BSCM resection.

Natural History, Clinical, and Surgical Management of Cavernous Malformations

We describe Natural history, clinical and surgical management of cavernous malformation of the brain and spinal cord. Decision-making for treatment of cavernous malformations cannot ignore their natural history and risk of bleeding, which is different depending on the location. Surgical morbidity also depends on the position of the lesion. We performed a review of hemorrhage risk and clinical assessment of superficial and deep supratentorial, brainstem and intramedullary cavernous malformations.

Outcomes of Surgery for Brainstem Cavernous Malformations

Background and Purpose—

The goal of this study was to systematically review the outcomes and complications after surgical resection of brain stem cavernous malformations (BCMs).

Methods—

A systematic literature review was performed using the PubMed database for studies published between 1986 and 2018. All studies comprising ≥2 patients with surgically resected BCMs and available follow-up data were included. Data extracted from studies included patient demographics, BCM location, and surgical outcomes.

Results—

Eighty-six studies comprising 2493 patients (adult and pediatric) were included for final analysis. Complete resection was achieved in 92.3% (fixed-effects pooled estimate [FE], 92.9% [91.7%–94.0%]; random-effects pooled estimate [RE], 89.4% [86.5%–92.0%]) of patients, and rehemorrhage of residual BCMs occurred in 58.6% (FE, 58.8% [49.7%–67.6%]; RE, 57.2% [43.5%–70.2%]). Postoperative morbidity occurred in 34.8% (FE, 30.9% [29.0%–32.8%]; RE, 31.1% [25.8%–36.6%]) of patients. Postoperative morbidities included motor deficit in 11.0% (FE, 9.9% [8.1%–11.7%]; RE, 11.1% [7.0%–16.0%]), sensory deficit in 6.7% (FE, 6.3% [4.8%–7.9%]; RE, 7.6% [4.5%–11.5%]), tracheostomy/gastrostomy in 6.0% (FE, 5.2% [4.3%–6.1%]; RE, 3.8% [2.6%–5.3%]), and other cranial nerve deficits in 29.4% (FE, 27.6% [25.3%–29.9%]; RE, 33.9% [25.7%–42.6%]) of patients. At final follow-up, 57.9% (FE, 57.6% [55.6%–59.6%]; RE, 57.2% [52.1%–62.3%]) and 25.9% (FE, 24.1% [22.4%–25.9%]; RE, 18.5% [14.6%–22.8%]) of patients had improvement and stability of preoperative symptoms, respectively. Mortality rate was 1.6% (FE, 1.9% [1.4%–2.5%]; RE, 1.8% [1.4%–2.5%]).

Conclusions—

High cure rates and low rates of postoperative morbidity can be achieved with surgery in patients with BCMs. Most patients had improved preoperative symptoms at final follow-up. To avoid rehemorrhage, complete resection should be the goal of surgery.

Subtemporal approach for the resection of a midbrain cavernous malformation: evaluation of safe surgical corridors

Brainstem cavernous malformation management is complex due to its critical location and deleterious effect when bleeding. Therefore, every case should be thoroughly analyzed preoperatively. We present the case of a female patient with a midbrain cavernous malformation. A comprehensive anatomical and clinical analysis of the surgical corridors is done to decide the safest route. A subtemporal approach was done and the lateral mesencephalic sulcus and vein were important anatomical landmarks to guide the safe entry zone. Nuances of technique and surgical pearls related to the safe entry zones of the midbrain are discussed and illustrated in this operative video.

The video can be found here: https://youtu.be/vYA-IgiT2lU.

Timing of Surgery and Surgical Strategies in Symptomatic Brainstem Cavernomas: Review of the Literature

Brainstem cavernomas (BSCs) are angiographically occult, benign low flow vascular malformations that pose a significant surgical challenge due to their eloquent location. The present study includes an extensive review of the literature and three illustrative cases of BSC with emphasis on the timing of surgery: surgical approaches, usage of intraoperative monitoring, and complication avoidance. A systematic search was performed using the PubMed database was from January 1, 1999, to June 2018. The relevant articles were reviewed with particular attention to hemorrhage rates, timing of surgery, indications for surgery, surgical approaches, and outcome. Along with this, a retrospective analysis of three cases of symptomatic BSC, who were operated for the same, during the year 2018 in our institute was conducted. All the three patients presented with at least 1 episode of hemorrhage before surgery. Of these, one patient was operated immediately due to altered sensorium whereas the other two were operated after at least 4 weeks of the hemorrhagic episode. The patients who were operated in the subacute phase of bleed were seen to have liquefaction of hematoma, thus providing a good surgical demarcation and thereby reduced surgery-related trauma to the surrounding eloquent structures. Two patients improved neurologically during the immediate postoperative period, whereas one had transient worsening of neurological deficits during the immediate postoperative period in the form of additional cranial nerve palsies which completely improved on follow-up after 2 months. Radical resection is recommended in all patients with symptomatic BSCs. Surgery should be considered after the first or the second episode of hemorrhage as multiple rebleeds can cause exacerbation of deficits and sometimes mortality as well. Considering surgical timing, anywhere between 4 and 6 weeks or the subacute phase of the hemorrhage is considered appropriate. The aims of surgical intervention must be to improve preoperative function, minimize surgical morbidity and to reduce hemorrhagic rates. In spite of the significant surgical morbidity associated with BSCs, appropriate patient selection, meticulous surgical planning with adjuncts such as intraoperative monitoring and neuronavigation will go a long way in avoidance of major postoperative complications.

Surgical Management and Risk Factors of Postoperative Respiratory Dysfunction of Cavernous Malformations Involving the Medulla Oblongata

OBJECTIVE

To evaluate surgical management of cavernous malformations (CMs) involving the medulla oblongata and to predict risk factors of postoperative respiratory dysfunction (RDF).

METHODS

Patient data from individuals who underwent surgical treatment for CMs involving the medulla oblongata were retrospectively reviewed. Patients with postoperative RDF and/or deficits of the cough reflex (CR, ≥7 days) were deemed as having bad respiratory statuses. A binary logistic regression analysis tested the association of preoperative predictors with bad postoperative respiratory status.

RESULTS

The study consisted of 69 patients. Preoperatively, 9 patients (13.0%) had dyspnea, and 4 (5.8%) had hypoxemia. Postoperatively, 11 patients (15.9%) had bad respiratory statuses, including RDF as a respiratory rhythm disorder and/or dyspnea in 6 patients, and ≥7 days of CR deficits in 5 patients. With a mean follow-up duration of 35.3 months, the neurologic status improved in 45 patients (68.2%), remained unchanged in 11 (16.7%), and worsened in 10 (15.1%) relative to the preoperative baseline. A multivariate logistic regression analysis identified that the independent adverse factors of bad postoperative respiratory status were multiple preoperative hemorrhages, large lesion size, and surgical intervention during the chronic period (>8 weeks).

CONCLUSIONS

Postoperative RDF and CR deficits could commonly occur in patients with CMs involving the medulla oblongata. However, patients with fewer preoperative hemorrhages, small lesion size, and operation within 8 weeks of the last bleeding are prone to be associated with a reduced possibility of bad postoperative respiratory status.

Long-Term Outcome of Gamma Knife Radiosurgery for Symptomatic Brainstem Cavernous Malformation

OBJECTIVE

We sought to analyze the long-term outcome of Gamma Knife radiosurgery (GKS) for symptomatic brainstem cavernous malformation (s-BSCM).

METHODS

Forty-five patients (14 males, 31 females) were treated with GKS for s-BSCM from January 1998 to December 2011. All patients were followed up for >5 years, and their clinical data were analyzed retrospectively. All patients had a history of symptomatic bleeding once or more before GKS. These hemorrhages caused neurologic deficits including cranial nerve deficits, hemiparesis, hemisensory deficits, spasticity, or chorea. The mean target volume of s-BSCM was 1.82 cm³, and the median prescribed marginal dose of radiation was 13 Gy. The mean clinical and imaging follow-up period was 9.31 years (range 5.1-19.4 years).

RESULTS

The 45 patients had 69 hemorrhagic events before GKS. During the follow-up period after GKS, 35 patients had no hemorrhagic event, 6 patients had 1 episode of symptomatic hemorrhage, and 4 patients had 2 episodes. The calculated annual hemorrhage rate was 40.06% at pre-GKS, 3.3% at 2 years after GKS, 1.48% at 5 years after GKS, and 4.64% at >5 years after GKS. In this study of 45 patients, symptomatic radiation-induced complications developed in only 1 patient (2.2%). No patients had died at the last follow-up.

CONCLUSIONS

GKS for s-BSCM is a safe and effective alternative to surgical resection for reducing the rate of recurrent hemorrhage. Because the annual hemorrhage rate increases >5 years after GKS, clinicians should monitor patients closely to determine their subsequent treatment.