Srinivas Chivukula

Volume-staged versus dose-staged radiosurgery outcomes for large intracranial arteriovenous malformations

OBJECT The aim in this paper was to compare the outcomes of dose-staged and volume-staged stereotactic radio-surgery (SRS) in the treatment of large (> 10 cm(3)) arteriovenous malformations (AVMs). METHODS A systematic literature review was performed using PubMed. Studies written in the English language with at least 5 patients harboring large (> 10 cm(3)) AVMs treated with dose- or volume-staged SRS that reported post-treatment outcomes data were selected for review. Demographic information, radiosurgical treatment parameters, and post-SRS outcomes and complications were analyzed for each of these studies. RESULTS The mean complete obliteration rates for the dose- and volume-staged groups were 22.8% and 47.5%, respectively. Complete obliteration was demonstrated in 30 of 161 (18.6%) and 59 of 120 (49.2%) patients in the dose- and volume-staged groups, respectively. The mean rates of symptomatic radiation-induced changes were 13.5% and 13.6% in dose- and volume-staged groups, respectively. The mean rates of cumulative post-SRS latency period hemorrhage were 12.3% and 17.8% in the dose- and volume-staged groups, respectively. The mean rates of post-SRS mortality were 3.2% and 4.6% in dose- and volume-staged groups, respectively. CONCLUSIONS Volume-staged SRS affords higher obliteration rates and similar complication rates compared with dose-staged SRS. Thus, volume-staged SRS may be a superior approach for large AVMs that are not amenable to single-session SRS. Staged radiosurgery should be considered as an efficacious component of multimodality AVM management.

Seizure outcomes following radiosurgery for cerebral arteriovenous malformations.

OBJECT Seizures are a common presentation of cerebral arteriovenous malformations (AVMs). The authors evaluated the efficacy of stereotactic radiosurgery (SRS) for the management of seizures associated with AVMs and identified factors influencing seizure outcomes following SRS for AVMs. METHODS A systematic literature review was performed using PubMed. Studies selected for review were published in English, included at least 5 patients with both cerebral AVMs and presenting seizures treated with SRS, and provided post-SRS outcome data regarding obliteration of AVMs and/or seizures. Demographic, radiosurgical, radiological, and seizure outcome data were extracted and analyzed. All seizure outcomes were categorized as follows: 1) seizure free, 2) seizure improvement, 3) seizure unchanged, and 4) seizure worsened. Systematic statistical analysis was conducted to assess the effect of post-SRS AVM obliteration on seizure outcome. RESULTS Nineteen case series with a total of 3971 AVM patients were included for analysis. Of these, 28% of patients presented with seizures, and data for 997 patients with available seizure outcome data who met the inclusion criteria were evaluated. Of these, 437 (43.8%) patients achieved seizure-free status after SRS, and 530 (68.7%) of 771 patients with available data achieved seizure control (seizure freedom or seizure improvement) following SRS. Factors associated with improved seizure outcomes following SRS for AVMs were analyzed in 9 studies. Seizure-free status was achieved in 82% and 41.0% of patients with complete and incomplete AVM obliteration, respectively. Complete AVM obliteration offered superior seizure-free rates compared with incomplete AVM obliteration (OR 6.13; 95% CI 2.16-17.44; p = 0.0007). CONCLUSIONS Stereotactic radiosurgery offers favorable seizure outcomes for AVM patients presenting with seizures. Improved seizure control is significantly more likely with complete AVM obliteration.

Endoscopic endonasal skull base surgery in the pediatric population.

OBJECT The use of endoscopic endonasal surgery (EES) for skull base pathologies in the pediatric population presents unique challenges and has not been well described. The authors reviewed their experience with endoscopic endonasal approaches in pediatric skull base surgery to assess surgical outcomes and complications in the context of presenting patient demographics and pathologies. METHODS A retrospective review of 133 pediatric patients who underwent EES at our institution from July 1999 to May 2011 was performed. RESULTS A total of 171 EESs were performed for skull base tumors in 112 patients and bony lesions in 21. Eighty-five patients (63.9%) were male, and the mean age at the time of surgery was 12.7 years (range 2.3-18.0 years). Skull base tumors included angiofibromas (n = 24), craniopharyngiomas (n = 16), Rathke cleft cysts (n = 12), pituitary adenomas (n = 11), chordomas/chondrosarcomas (n = 10), dermoid/epidermoid tumors (n = 9), and 30 other pathologies. In total, 19 tumors were malignant (17.0%). Among patients with follow-up data, gross-total resection was achieved in 16 cases of angiofibromas (76.2%), 9 of craniopharyngiomas (56.2%), 8 of Rathke cleft cysts (72.7%), 7 of pituitary adenomas (70%), 5 of chordomas/chondrosarcomas (50%), 6 of dermoid/epidermoid tumors (85.7%), and 9 cases of other pathologies (31%). Fourteen patients received adjuvant radiotherapy, and 5 received chemotherapy. Sixteen patients (15.4%) showed tumor recurrence and underwent reoperation. Bony abnormalities included skull base defects (n = 12), basilar invagination (n = 4), optic nerve compression (n = 3) and trauma (n = 2); preexisting neurological dysfunction resolved in 12 patients (57.1%), improved in 7 (33.3%), and remained unchanged in 2 (9.5%). Overall, complications included CSF leak in 14 cases (10.5%), meningitis in 5 (3.8%), transient diabetes insipidus in 8 patients (6.0%), and permanent diabetes insipidus in 12 (9.0%). Five patients (3.8%) had transient and 3 (2.3%) had permanent cranial nerve palsies. The mean follow-up time was 22.7 months (range 1-122 months); 5 patients were lost to follow-up. CONCLUSIONS Endoscopic endonasal surgery has proved to be a safe and feasible approach for the management of a variety of pediatric skull base pathologies. When appropriately indicated, EES may achieve optimal outcomes in the pediatric population.

Stereotactic radiosurgery for intracranial dural arteriovenous fistulas: a systematic review.

OBJECT The goal of this study was to evaluate the obliteration rate of intracranial dural arteriovenous fistulas (DAVFs) in patients treated with stereotactic radiosurgery (SRS), and to compare obliteration rates between cavernous sinus (CS) and noncavernous sinus (NCS) DAVFs, and between DAVFs with and without cortical venous drainage (CVD). METHODS A systematic literature review was performed using PubMed. The CS DAVFs and the NCS DAVFs were categorized using the Barrow and Borden classification systems, respectively. The DAVFs were also categorized by location and by the presence of CVD. Statistical analyses of pooled data were conducted to assess complete obliteration rates in CS and NCS DAVFs, and in DAVFs with and without CVD. RESULTS Nineteen studies were included, comprising 729 patients harboring 743 DAVFs treated with SRS. The mean obliteration rate was 63% (95% CI 52.4%-73.6%). Complete obliteration for CS and NCS DAVFs was achieved in 73% and 58% of patients, respectively. No significant difference in obliteration rates between CS and NCS DAVFs was found (OR 1.72, 95% CI 0.66-4.46; p=0.27). Complete obliteration in DAVFs with and without CVD was observed in 56% and 75% of patients, respectively. A significantly higher obliteration rate was observed in DAVFs without CVD compared with DAVFs with CVD (OR 2.37, 95% CI 1.07-5.28; p=0.03). CONCLUSIONS Treatment with SRS offers favorable rates of DAVF obliteration with low complication rates. Patients harboring DAVFs that are refractory or not amenable to endovascular or surgical therapy may be safely and effectively treated using SRS.

Endoscopic Endonasal Skull Base Surgery in the Pediatric Population

OBJECT The use of endoscopic endonasal surgery (EES) for skull base pathologies in the pediatric population presents unique challenges and has not been well described. The authors reviewed their experience with endoscopic endonasal approaches in pediatric skull base surgery to assess surgical outcomes and complications in the context of presenting patient demographics and pathologies. METHODS A retrospective review of 133 pediatric patients who underwent EES at our institution from July 1999 to May 2011 was performed. RESULTS A total of 171 EESs were performed for skull base tumors in 112 patients and bony lesions in 21. Eighty-five patients (63.9%) were male, and the mean age at the time of surgery was 12.7 years (range 2.3-18.0 years). Skull base tumors included angiofibromas (n = 24), craniopharyngiomas (n = 16), Rathke cleft cysts (n = 12), pituitary adenomas (n = 11), chordomas/chondrosarcomas (n = 10), dermoid/epidermoid tumors (n = 9), and 30 other pathologies. In total, 19 tumors were malignant (17.0%). Among patients with follow-up data, gross-total resection was achieved in 16 cases of angiofibromas (76.2%), 9 of craniopharyngiomas (56.2%), 8 of Rathke cleft cysts (72.7%), 7 of pituitary adenomas (70%), 5 of chordomas/chondrosarcomas (50%), 6 of dermoid/epidermoid tumors (85.7%), and 9 cases of other pathologies (31%). Fourteen patients received adjuvant radiotherapy, and 5 received chemotherapy. Sixteen patients (15.4%) showed tumor recurrence and underwent reoperation. Bony abnormalities included skull base defects (n = 12), basilar invagination (n = 4), optic nerve compression (n = 3) and trauma (n = 2); preexisting neurological dysfunction resolved in 12 patients (57.1%), improved in 7 (33.3%), and remained unchanged in 2 (9.5%). Overall, complications included CSF leak in 14 cases (10.5%), meningitis in 5 (3.8%), transient diabetes insipidus in 8 patients (6.0%), and permanent diabetes insipidus in 12 (9.0%). Five patients (3.8%) had transient and 3 (2.3%) had permanent cranial nerve palsies. The mean follow-up time was 22.7 months (range 1-122 months); 5 patients were lost to follow-up. CONCLUSIONS Endoscopic endonasal surgery has proved to be a safe and feasible approach for the management of a variety of pediatric skull base pathologies. When appropriately indicated, EES may achieve optimal outcomes in the pediatric population.

Cervical and cervicomedullary spinal cord stimulation for chronic pain: efficacy and outcomes.

BACKGROUND The role for spinal cord stimulation (SCS) in the management of chronic spinal cord forms of pain involving cervical dermatomes or the cervicomedullary junction (CMJ) for facial pain remains largely uncharted. OBJECTIVE To review outcomes with cervical and CMJ SCS performed by a single surgeon, with particular emphasis on complications and efficacy. METHODS All patients that underwent cervical or CMJ SCS by the lead author were identified and follow-up obtained by telephone questionnaires. Patient demographics, surgical details, outcomes and complications for all patients identified were critically reviewed. RESULTS Of 121 patients identified that underwent at least trial SCS, 100 underwent permanent lead implantation. Indications for cervical SCS included brachial plexus lesions (8), complex regional pain syndrome (33), degenerative disc disease (4), failed neck surgery syndrome (23), chronic radiculopathy (6) and post-herpetic neuralgia (PHN) (1); for CMJ SCS, indications included trigeminal deafferetiation pain (10), trigeminal neuropathic pain (4), PHN (4) and occipital neuralgia (7). Pain relief was greater along the extremities than axially, and less in the occipital area than in the head or face. Mean pain reduction averaged 56.6% at a mean follow-up of 4.2 years. Of 24 revision surgeries required, 8 were for presumed lead migration or fracture. Complications included 4 CSF leaks, 5 wound infections, and 4 cases of persistent numbness or pain. Pain relief lasted an average of 3.6 years. CONCLUSION Cervical and CMJ SCS are safe and efficacious and may provide greater relief along the upper extremities than axially, and in the head rather than in the occipital region.

Ommaya reservoir with ventricular catheter placement for chemotherapy with frameless and pinless electromagnetic surgical neuronavigation

BACKGROUND Accuracy in Ommaya reservoir catheter placement is critical to chemotherapy infusion. Most frameless image guidance is light emitting diode (LED) based, requiring a direct line of communication between instrument and tracker, limiting freedom of instrument movement within the surgical field. Electromagnetic neuronavigation may overcome this challenge. OBJECTIVE To compare Ommaya reservoir ventricular catheter placement using electromagnetic neuronavigation to LED-based optical navigation, with emphasis on placement accuracy, operative time and complication rate. METHODS Twenty-eight patients who underwent placement of Ommaya reservoirs at our institution between 2010 and 2014 with either electromagnetic (12 patients) or optical neuronavigation (16 patients) were retrospectively reviewed. RESULTS Half of the patients were male. Their mean age was 56 years (range 28-87 years). Accuracy and precision in catheter tip placement at the target site (foramen of Monro) were both higher (p=0.038 and p=0.043, respectively) with electromagnetic neuronavigation. Unintended placement of the distal catheter contralateral to the target site occurred more frequently with optical navigation, as did superior or inferior positioning by more than 5 mm. Mean operative times were shorter (p=0.027) with electromagnetic neuronavigation (43.2 min) than with optical navigation (51.0 min). There were three complications (10.7%)--one case each of cytotoxic edema, post-operative wound infection, and urinary tract infection. The rate of complication did not differ between groups. CONCLUSION In contrast with optical neuronavigation, frameless and pinless electromagnetic image guidance allows the ability to track instrument depth in real-time. It may increase ventricular catheter placement accuracy and precision, and decrease operative times.

Spinal and Nucleus Caudalis Dorsal Root Entry Zone Lesioning for Chronic Pain: Efficacy and Outcomes

BACKGROUND The role for nucleus caudalis (NC) and spinal dorsal root entry zone (DREZ) lesioning in the management of chronic pain emanating from increased electrical activity in the dorsal horn of the spinal cord and brainstem remains largely uncharted. METHODS All patients who underwent NC and spinal DREZ lesioning by a single surgeon were identified and follow-up was obtained by telephone questionnaires. Patient demographics, surgical details, outcomes, and complications were critically reviewed for all patients identified. RESULTS Of 83 patients identified, 53 (63.9%) were male. Indications for NC DREZ lesioning included trigeminal neuropathic pain (6), trigeminal deafferentation pain (3), glossopharyngeal or occipital neuralgia (3), post-herpetic neuralgia (3), and trauma (1); for spinal DREZ lesioning, indications included brachial plexus avulsion (20), post-herpetic neuralgia (19), spinal cord injury (11), phantom limb pain (8), pelvic pain (5), and complex regional pain syndrome (4). Pain relief was most significant among patients with trigeminal pain, traumatic brachial plexus avulsion injuries, spinal cord injury, and traumatic phantom limb pain. Mean pain reduction averaged 58.3% at a mean follow-up of 8.3 years. Complications included 3 cases of paresis, 3 cases of neuropathy/radiculopathy, 2 cases of ataxia, 3 general medical conditions (colitis, 2; atelectasis, 1), and 2 cases of persistent incisional site pain. Pain relief lasted an average of 4.3 years. CONCLUSIONS Spinal and NC DREZ lesioning can provide effective relief in well-selected patients with intractable chronic pain conditions arising from trigeminal pain, spinal cord injury, brachial plexus avulsions, post-herpetic neuralgia, and phantom limb pain.

The results of a third Gamma Knife procedure for recurrent trigeminal neuralgia

OBJECT Gamma Knife radiosurgery (GKRS) is the least invasive treatment option for medically refractory, intractable trigeminal neuralgia (TN) and is especially valuable for treating elderly, infirm patients or those on anticoagulation therapy. The authors reviewed pain outcomes and complications in TN patients who required 3 radiosurgical procedures for recurrent or persistent pain. METHODS A retrospective review of all patients who underwent 3 GKRS procedures for TN at 4 participating centers of the North American Gamma Knife Consortium from 1995 to 2012 was performed. The Barrow Neurological Institute (BNI) pain score was used to evaluate pain outcomes. RESULTS Seventeen patients were identified; 7 were male and 10 were female. The mean age at the time of last GKRS was 79.6 years (range 51.2-95.6 years). The TN was Type I in 16 patients and Type II in 1 patient. No patient suffered from multiple sclerosis. Eight patients (47.1%) reported initial complete pain relief (BNI Score I) following their third GKRS and 8 others (47.1%) experienced at least partial relief (BNI Scores II-IIIb). The average time to initial response was 2.9 months following the third GKRS. Although 3 patients (17.6%) developed new facial sensory dysfunction following primary GKRS and 2 patients (11.8%) experienced new or worsening sensory disturbance following the second GKRS, no patient sustained additional sensory disturbances after the third procedure. At a mean follow-up of 22.9 months following the third GKRS, 6 patients (35.3%) reported continued Score I complete pain relief, while 7 others (41.2%) reported pain improvement (BNI Scores II-IIIb). Four patients (23.5%) suffered recurrent TN following the third procedure at a mean interval of 19.1 months. CONCLUSIONS A third GKRS resulted in pain reduction with a low risk of additional complications in most patients with medically refractory and recurrent, intractable TN. In patients unsuitable for other microsurgical or percutaneous strategies, especially those receiving long-term oral anticoagulation or antiplatelet agents, GKRS repeated for a third time was a satisfactory, low risk option.

Outcomes After Endoscopic Port Surgery for Spontaneous Intracerebral Hematomas

BACKGROUND Spontaneous intracerebral hemorrhages (ICHs) cause significant morbidity and mortality. Traditional open surgical management strategies offer limited benefit except for the most superficial hemorrhages in select patients. Recent reports suggest that endoscopic approaches may improve outcomes, particularly for deep subcortical hemorrhages. However, the management of these patients remains controversial. We reviewed our experience using endoscopic port surgery to identify characteristics that may predict acceptable outcomes. MATERIALS AND METHODS We completed a retrospective chart and imaging review of patients who underwent endoscopic port surgery for evacuation of spontaneous ICH at a single center. Data were gathered regarding patient demographics, hemorrhage locations, operative findings, and clinical outcomes. RESULTS From 2007 to 2011, 18 patients underwent evacuation of spontaneous intracerebral hematomas using an endoscopic port. The mean age in years was 62 years (range, 43-84 years). Six of 18 patients (33%) died before discharge, and 2 others (11%) died after at least 1 month of survival. Of 12 initial survivors, all were discharged to a rehabilitation or nursing facility. Complete hematoma evacuation was achieved in 7 of 18 patients, with the remaining 11 having a partial evacuation. The patients who died (n = 6) before discharge were statistically more likely to have a left-sided hemorrhage, partial evacuation, or older age than the survivors; death at least 1  month after evacuation was additionally associated with greater preoperative hematoma volumes. CONCLUSIONS Our series demonstrates that endoscopic port surgery for acute intracerebral hematoma evacuation has the ability to achieve significant decompression of large and deep-seated hematomas. Patient age, extent of evacuation, laterality, and preoperative hematoma volume appear to influence patient outcome. Most overall outcomes remain poor. Future studies are necessary to determine if surgical evacuation is in fact superior to best medical treatment and if so, to validate, refute, or further identify characteristics that define surgical candidates.