Intradural "limited drill" technique of anterior clinoidectomy and optic canal unroofing for microneurosurgical management of ophthalmic segment and PCOM aneurysms-review of surgical results.

To evaluate the safety and efficacy of intradural "limited drill" technique (ILDT) of anterior clinoidectomy (AC) and optic canal unroofing (OCU) for microneurosurgical management of ophthalmic segment and posterior communicating artery (PCOM) aneurysms. All the patients with ophthalmic segment and PCOM aneurysms who underwent AC and OCU by ILDT for microneurosurgical management of ophthalmic segment and PCOM aneurysms during 4-year period (2013-2016) at our Institute were included in this study. In ILDT of AC and OCU, the use of power drill is restricted to AC only and OCU is done exclusively with 1-mm Kerrison punch. AC and OCU by ILDT were done in 24 patients with 29 ophthalmic segment and 7 PCOM aneurysms. AC and OCU by ILDT helped in mobilization of optic nerve/internal carotid artery (ICA) and provided excellent exposure for all these aneurysms. There was no injury to ICA or optic nerve during drilling. AC and OCU facilitated clip ligation of 34 of these aneurysms. Remaining 2 aneurysms were considered not suitable for clipping. Check angiogram done for 33 aneurysms revealed complete obliteration of 26 aneurysms, very small residual neck in 5 aneurysms, and small residual aneurysm in 2 aneurysms. Deterioration in vision was noted in 1 patient (4.1%). In 6 patients with preoperative visual deficits, significant improvement in vision was noted in 4 patients (4/6-66.6%) after surgery. Good outcome (MRS < 2) was noted in 91.6% (22/24) of these patients. ILDT is a safe and effective technique of AC and OCU which provide good exposure for ophthalmic segment and PCOM aneurysms.

Occipital Interhemispheric Transtentorial Approach for Tumors of Posterior Third Ventricular Region: Review of Surgical Results.

Background: Controversies exist regarding the ideal surgical approach for tumors in posterior third ventricular region (PTV). Objective: To evaluate the results of occipital interhemispheric transtentorial (OITT) approach for tumors in PTV. Materials And Methods: Thirty-three patients underwent surgery via OITT approach for PTV tumors at Sri Sathya Sai Institute of Higher Medical Sciences during the study period of 5 years (June 2011-May 2016). Ideal trajectory for OITT approach was determined by neuronavigation. Endoscope was used for removing any residual lesion at the blind spots. Results: Postoperative magnetic resonance imaging (MRI) performed in all the patients revealed gross total or near-total (>95%) excision of tumor in 31 patients (93.9%). Preoperative neurological deficits improved either completely or significantly following excision of the tumor in 73.3% (11/15) of the patients. Outcome was good (modified Rankin scale ≤2) at discharge in 93.9% (31/33) and at a final follow-up of 3 months or more in 96.8% (30/31) of the patients. None of the patients died during the postoperative period. Complications included upgaze palsy (transient- 6.1% [2/33], persisting- 3% [1/33]), visual field defects (transient- 3% [1/33], persisting- 3% [1/33]), transient third nerve paresis (1/33-3%), transient hemiparesis (1/33-3%), operative site hematoma (1/33-3%), small posterior cerebral artery (PCA) territory infarct (1/33-3%), and small venous infarct (1/33-3%). At least one follow-up MRI could be performed in 23 patients. Final follow-up MRI revealed no recurrence or increase in the size of the residual lesion compared to postoperative images in 20 patients (20/23-87%) and large recurrence in 3 patients (3/23-13%) with high-grade lesions. Conclusion: Gross total/near-total excision can be performed in majority of the PTV tumors through OITT approach with minimal morbidity and mortality.

Outcome of Surgery for Congenital Craniovertebral Junction Anomalies with Atlantoaxial Dislocation/Basilar Invagination: A Retrospective Study of 94 Patients.

OBJECTIVE: To evaluate the results of surgery for congenital craniovertebral junction (CVJ) anomalies with atlantoaxial dislocation (AAD)/basilar invagination (BI) and compare the results of transoral odontoidectomy and posterior fusion (TOO+PF) with only posterior fusion (PF) in patients with irreducible AAD/BI. METHODS AND RESULTS: All 94 patients with congenital CVJ anomalies with AAD/BI operated on during the 3-year study period (June 2013-May 2016) were included. Of these patients, 55 had irreducible AAD/BI and the remaining 39 had reducible AAD/BI. TOO+PF was restricted to patients (34/94; 36.2%) with irreducible AAD/BI when reduction and realignment by intraoperative C1-C2 facet joint manipulation were considered technically difficult and risky. The remaining patients with irreducible AAD/BI and all the patients with reducible AAD/BI (60/94; 63.8%) were managed with only posterior fusion. Poor preoperative Nurick grade, preoperative dyspnea/lower cranial nerve deficits, and syringomyelia were associated with significantly higher incidence of postoperative pulmonary complications. Follow-up ≥3 months (final follow-up) was available for 87 patients. Good outcome (Nurick grade 0-3) at final follow-up was noted in 90% (45/50) of the patients with irreducible AAD/BI and 91.9% (34/37) of the patients with reducible AAD/BI. Preoperative poor Nurick grade (4-5) was the only factor associated with poor outcome. No significant difference in perioperative complications, outcome, and fusion was noted between patients who underwent TOO+PF or only PF for irreducible AAD/BI. CONCLUSIONS: Many of the patients with congenital AAD/BI showed remarkable recovery after surgery. Preoperative poor Nurick grade (4-5) is associated with poor outcome. TOO+PF is a safe alternative treatment option for irreducible AAD/BI when only PF techniques are technically difficult/risky.

Outcome of Microsurgical Clipping for Multiple Versus Single Intracranial Aneurysms: A Single-Institution Retrospective Comparative Cohort Study.

OBJECTIVE: To evaluate the results of microsurgical clipping for single intracranial aneurysm (SIA) and multiple intracranial aneurysms (MIA) and compare the outcomes. METHODS: All patients who underwent surgery for intracranial aneurysm (IA) at our institution over a 3-year period (June 2013 to May 2016) were included in this study. RESULTS: A total of 157 patients with 225 IAs were included. Forty-one of these patients had MIA (109 IAs, mean, 2.7 ± 1.2; range, 2-7), and remaining 116 had SIA. In the patients with MIA, all aneurysms were secured during the same admission whenever possible. Depending on the locations of the IAs and condition of brain during surgery (tense/lax), all aneurysms were secured on same day (in a single session, single or multiple craniotomy in 28 patients) or on different days (multiple sessions in 13 patients). Postoperative control angiography (DSA) before discharge could be done for 216 aneurysms (MIA, n = 105; SIA, n = 111). Successful occlusion of the aneurysm from circulation was noted in 96.2% (101/105) of MIA and 93.7% (104/111) of SIA. Follow-up of 6 months or longer was available for 146 patients. A modified Rankin Scale score ≤2 was considered a good outcome. Univariate analysis of the entire group revealed no significant difference in clinical outcomes between patients with SIA and MIA both at discharge (good outcome: MIA, 82.9%; SIA, 93.1%; P = 0.068) and at a final follow-up of ≥6 months (good outcome: MIA, 87.2%; SIA, 94.4%; P = 0.164). Clipping for MIA was not associated with poor outcome in multivariate analysis. CONCLUSIONS: Comparable clinical outcomes and high rates of complete aneurysm occlusion following microsurgical clipping can be expected in patients with SIA and patients with MIA.

Microsurgery for Spetzler-Martin Grade I-III Arteriovenous Malformations: Analysis of Surgical Results and Correlation of Lawton-Young Supplementary Grade and Supplemented Spetzler-Martin Score with Functional Outcome.

OBJECTIVE: To analyze the results of microsurgery for Spetzler-Martin (SM) grade I-III AVMs and evaluate the correlation of the Lawton-Young (LY) supplementary grade, supplemented Spetzler-Martin (SM-Supp/combined) score with the functional outcome. METHODS: A total of 42 patients with SM grade I-III AVMs who had undergone surgery at our institute during a 3-year period (June 2013 to May 2016) were included in the present study. RESULTS: All 42 patients had undergone primary surgery without previous embolization. Three patients (7.1%) had died due to surgical site hematoma in the postoperative period. One patient was lost to follow-up. The mean follow-up period for the remaining patients was 27 ± 14 months (range, 12-62 months). At the final follow-up examination of ≥12 months (FFU), 92.7% of the patients had a good outcome (modified Rankin scale [mRS] score ≤1), with an improved or unchanged mRS score in 87.8%. An AVM size >3 cm, diffuse AVM, SM grade III, and SM-Supp score >5 were associated with worsened mRS score at discharge and FFU. Higher LY grade (IV and V), eloquent AVM location, deep venous drainage, age >40 years, and unruptured presentation were not associated with worsened mRS score at both discharge and FFU. Of the 20 ARUBA-eligible patients, 19 (95%) had good outcomes. Postoperative angiograms for 39 patients revealed complete excision of the AVM in 37 (94.9%) and a residual AVM in 2 (5.1%). CONCLUSIONS: High cure rates and excellent clinical outcomes can be expected with microsurgery for most patients with SM grade I-III AVMs. An AVM size >3 cm, diffuse AVM nidus, SM grade III, and SM-Supp score >5 are associated with postoperative worsening of functional scores in patients with SM grade I-III AVMs.

Adenosine-Induced transient asystole during surgical treatment of basilar artery aneurysms.

AIM: To evaluate the safety and efficacy of adenosine-induced transient asystole (AITA) during surgery for basilar artery aneurysms. MATERIALS AND METHODS: All the patients with basilar artery aneurysms operated using AITA at our institute during two years period (August 2013-July 2015) were included in this study. RESULTS: Adenosine was used in 11 patients with 13 basilar artery aneurysms. Seven of these aneurysms were basilar bifurcation aneurysms, four were basilar-superior cerebellar artery junction aneurysms, and two were distal basilar trunk aneurysms. The indications for AITA were narrow corridor for placement of temporary clip in 11 aneurysms, intraop rupture in 1 aneurysm, and circumferential dissection of a large aneurysm in 1. The mean dose of adenosine used for inducing asystole was 19.4 mg (range: 15-30 mg) and the mean total dose of adenosine used was 40.6 mg (range: 18-90 mg). A mean of 2 (range: 1-5) AITAs were required during surgical treatment of these aneurysms. The mean duration of a systole was 27 s (range: 9-76 s). There were no complications related to AITA in these patients except for transient rebound hypertension in one patient. Check angiogram revealed complete obliteration of 11 aneurysms and small residual neck in 2 aneurysms. Modified Rankin Scale at three months of follow-up was 0 in seven patients, 1 in two patients, 4 in one patient, and 6 in one patient. CONCLUSION: AITA during surgical management of basilar artery aneurysms is a safe and effective technique and has an important role during surgery for these aneurysms.

Far lateral approach without occipital condylar resection for intradural ventral/ventrolateral foramen magnum tumors and aneurysms of V4 segment of vertebral artery: Review of surgical results.

BACKGROUND: Controversies exist regarding the need and extent of condylar resection for safe surgical management of intradural ventral/ventrolateral foramen magnum (VFM) tumors and aneurysms of V4 segment of vertebral artery (VA) by far lateral approach. This retrospective study was conducted to evaluate the results of basic far lateral approach(retrocondylar approach) without upfront occipital condylar resection. METHODS AND RESULTS: Twenty one patients underwent surgery via far lateral approach for intradural VFM tumors and aneurysms of V4 segment of VA at Sri Sathya Sai Institute of Higher Medical Sciences during 9 years(2008-2016) study period. Eight patients had VA aneurysms and 13 patients had intradural VFM tumors. After basic far lateral approach(retrocondylar approach), dura was opened and checked if the exposure was adequate for safe surgery. Retrocondylar approach provided adequate exposure for all these lesions and resection of occipital condyle/jugular tubercle was not required in any of these cases. Skeletonization or transposition of VA was not done in any of these cases. Gross total resection of the tumor could be done in 9 patients(9/13-69.2 %) and near total excision (>95 %) in 4 patients (4/13-30.8 %). Seven of the 8 VA aneurysms were successfully clipped. Outcome at a final follow up of 3 months or more was good(mRS<2) in 19 patients(19/21-90.5 %) and poor in 2 patients. Complications included lower cranial nerve deficits [transient-2/21(9.5 %), persisting-2/21(9.5 %)], motor deficits(2/21-9.5%), seventh nerve paresis(1/21-4.8%), sixth nerve paresis(2/21-9.5%) and pseudomeningocele(1/21-4.8%). CONCLUSION: Basic far lateral (retrocondylar) approach provides excellent exposure for majority of VFM tumors and aneurysms of V4 segment of VA. Condylar resection(transcondylar approach), drilling of jugular tubercle (transtubercular approach), skeletonization/transposition of VA might not be required for safe surgical management of majority of these lesions.

Safety and Accuracy of Anatomic and Lateral Fluoroscopic-Guided Placement of C2 Pars/Pedicle Screws and C1 Lateral Mass Screws, and Freehand Placement of C2 Laminar Screws.

OBJECTIVE: To evaluate the safety and accuracy of anatomic- and lateral fluoroscopic-guided placement of C2 pars/pedicle, C1 lateral mass screws, and freehand placement of C2 laminar screws. METHODS: All the patients who underwent posterior cervical/occipitocervical fixation that involved the placement of C1/C2 screws during a 5-year period (2011-2015) at our institute were included in this study. RESULTS: C1/C2 screws were placed in a total of 94 patients during this period. A total of 97 C1 lateral mass, 49 C2 pars, 24 C2 pedicle, and 82 C2 laminar screws were placed in these patients. C1 lateral mass screws and C2 pars/pedicle screws were placed under anatomic and lateral fluoroscopic guidance. C2 laminar screws were placed by a freehand technique. The mean length (range) of various C2 screws was 16.4 ± 2.6 mm (12-22 mm) for pars screws, 18.8 ± 2.7 mm (14-24 mm) for pedicle screws, and 25.6 ± 3.4 mm (18-32 mm) for laminar screws. Postoperative CT imaging done in all patients before discharge revealed malposition of 2 laminar screws with breach of the inner cortex. The position of the remaining C1/C2 screws was perfect. The superior and medial angulation of the pars screws and superior angulation of the pedicle screws as measured in postoperative CT images were found to significantly deviate from the angles described in the literature. There was no mortality, vertebral artery injury, or neurologic injury related to C1/C2 screw placement in this series. CONCLUSIONS: Anatomic and lateral fluoroscopic-guided placement of C2 pars/pedicle screws and C1 lateral mass screws and freehand placement of C2 laminar screws is extremely safe.