Surgical treatment of a giant paraophthalmic aneurysm postfailed flow diversion through endoscopic endonasal approach: Technical nuances and review of the literature.

Background: Giant internal carotid artery (ICA) aneurysms are usually treated through flow diversion, coiling, or a combination of both. However, certain cases that fail the endovascular treatment pose a technical challenge. Case Description: A 68-year-old male presented with gradual visual changes affecting his right eye and was found to have a giant unruptured right paraophthalmic aneurysm. The aneurysm showed growth, and the patient's symptoms worsened despite coiling and flow diversion. Due to the location of this aneurysm and persistent compression of the optic chiasm by the coil mass, his right ICA was sacrificed, and an expanded endoscopic endonasal approach was successfully used to clip the residual aneurysm, remove the coil mass, and thus, decompress the optic chiasm. The patient's visual symptoms improved after that, and post clipping imaging demonstrated adequate occlusion of his right paraophthalmic aneurysm. Conclusion: Recognizing the option of an endoscopic endonasal approach for clipping giant internal carotid aneurysms is of great importance. This approach can be safe and technically successful for the treatment of paraophthalmic aneurysms that fail the typical endovascular treatment.

Analysis of Olfaction after Bilateral Nasoseptal Rescue Flap Transsphenoidal Approach with Olfactory Mucosal Preservation.

OBJECTIVE: To ascertain the impact of septal olfactory strip preservation and bilateral rescue flap elevation on the incidence of olfactory dysfunction. STUDY DESIGN: Case series with chart review of patients undergoing endoscopic endonasal skull base surgery (2012-2014). SETTING: Providence Saint John's Health Center and John Wayne Cancer Institute. SUBJECTS AND METHODS: The incidences of postoperative epistaxis, hyposmia, and anosmia were analyzed using the Brief Smell Identification Test (B-SIT), which was completed in 110 of the 165 patients. RESULTS: Seventy-eight patients required extended approaches. Bilateral nasoseptal rescue flaps were elevated in 144 patients (87.3%) and pedicled nasoseptal or middle turbinate flaps in 21 patients (12.7%). The neurovascular pedicles were preserved in all patients, and there were no episodes of postoperative arterial epistaxis. Normal olfaction was noted in 95 patients (86%), with new hyposmia noted in 5 patients (5.5%). Within the rescue flap cohort, new hyposmia occurred in 6.3% (P < .01) of patients, balanced by improvement of olfaction in 43% of patients with preoperative dysfunction (overall pre- and postoperative olfactory function: 85% vs 86%). Patients with pedicled nasoseptal flaps did not have new hyposmia, with a net improvement of olfaction (71% vs 86%, P = .07). No patients experienced new anosmia. There was no difference between flap type within either subgroup. CONCLUSIONS: Superior olfactory strip preservation during elevation of reconstructive flaps preserves olfactory function and maintains adequate surgical exposure. In addition, rescue flaps have significantly diminished the rate of arterial postoperative epistaxis while maintaining the ability to harvest nasoseptal flaps for future reconstruction.

Atlantoaxial fixation using C1 posterior arch screws: feasibility study, morphometric data, and biomechanical analysis.

OBJECTIVEC1-2 is a highly mobile complex that presents unique surgical challenges to achieving biomechanical rigidity and fusion. Posterior wiring methods have been largely replaced with segmental constructs using the C1 lateral mass, C1 pedicle, C2 pars, and C2 pedicle. Modifications to reduce surgical morbidity led to the development of C2 laminar screws. The C1 posterior arch has been utilized mostly as a salvage technique, but recent data indicate that this method provides significant rigidity in flexion-extension and axial rotation. The authors performed biomechanical testing of a C1 posterior arch screw (PAS)/C2 pars screw construct, collected morphometric data from a population of 150 CT scans, and performed a feasibility study of a freehand C1 PAS technique in 45 cadaveric specimens.METHODSCervical spine CT scans from 150 patients were analyzed to determine the average C1 posterior tubercle thickness and size of C1 posterior arches. Eight cadavers were used to compare biomechanical stability of intact specimens, C1 lateral mass/C2 pars screw, and C1 PAS/C2 pars screw constructs. Paired comparisons were made using repeated-measures ANOVA and Holm-Sidak tests. Forty-five cadaveric specimens were used to demonstrate the feasibility and safety of the C1 PAS freehand technique.RESULTSMorphometric data showed the average craniocaudal thickness of the C1 posterior tubercle was 12.3 ± 1.94 mm. Eight percent (12/150) of cases showed thin posterior tubercles or midline defects. Average posterior arch thickness was 6.1 ± 1.1 mm and right and left average posterior arch length was 28.7 mm ± 2.53 mm and 28.9 ± 2.29 mm, respectively. Biomechanical testing demonstrated C1 lateral mass/C2 pars and C1 PAS/C2 pars constructs significantly reduced motion in flexion-extension and axial rotation compared with intact specimens (p < 0.05). The C1 lateral mass/C2 pars screw construct provided significant rigidity in lateral bending (p < 0.05). There was no statistically significant difference between the two constructs in flexion-extension, lateral bending, or axial rotation. Of the C1 posterior arches, 91.3% were successfully cannulated using a freehand technique with a low incidence of cortical breach (4.4%).CONCLUSIONSThis biomechanical analysis indicates equivalent stability of the C1 PAS/C2 pars screw construct compared with a traditional C1 lateral mass/C2 pars screw construct. Both provide significant rigidity in flexion-extension and axial rotation. Feasibility testing in 45 cadaveric specimens indicates a high degree of accuracy with low incidence of cortical breach. These findings are supported by a separate radiographic morphometric analysis.

Endoscopic and Gravity-Assisted Resection of Medial Temporo-occipital Lesions Through a Supracerebellar Transtentorial Approach: Technical Notes With Case Illustrations.

BACKGROUND: Traditional approaches to medial temporo-occipital intra-axial brain tumors carry the risk of visual or language deficits related to brain retraction or transgression of deep fiber tracts. To reduce these risks, the microscopic supracerebellar transtentorial approach with the patient in the sitting position has been previously described for lesions in relative proximity to the tentorium. OBJECTIVE: We describe this approach performed with endoscopic tumor resection to allow better visualization and a more ergonomic operating position. METHODS: Four consecutive patients harboring a medial temporo-occipital lesion are reported. All were operated on while in the sitting position using frameless navigation and a supracerebellar transtentorial approach. Tumor resection was performed by 2 surgeons with endoscopic visualization. RESULTS: Pathologies included intraparenchymal metastatic melanoma, cavernous hemangioma, and ganglioglioma, as well as an intraventricular metastatic tumor. The distance from the tentorium to the lesion ranged from 1 to 4 mm. Gross total resection was achieved in 3 of the 4 patients. The patient with a metastatic melanoma had an intentional near-total resection given the tumor encasing a branch of the posterior cerebral artery. The patient with the intraventricular tumor sustained a small but symptomatic infarct of the lateral geniculate region, resulting in a visual field deficit. CONCLUSION: This small series suggests that the endoscopic supracerebellar transtentorial approach with the patient in the sitting position can be a safe and effective approach for removing medial temporo-occipital lesions. It allows excellent tumor visualization, eliminates the need for brain retraction, minimizes parenchymal transgression, and improves surgical ergonomics. Significant experience in endoscopy and excellent neuroanesthesia support are recommended before undertaking this approach.

Sellar Masses that Present with Severe Hyponatremia.

OBJECTIVE: Hyponatremia is a known but underrecognized presentation of sellar lesions. Herein, we present a series of patients who presented with single or multiple episodes of hyponatremia. METHODS: Over 5 years, patients undergoing endonasal surgery for a de novo sellar mass with hyponatremia as an initial presentation were included. Pathology, sodium levels, pituitary hormonal status, and treatment course were documented. RESULTS: Of 282 patients, 16 (5.7%) (9 males, 7 females, age 32 to 84 years) presented with severe hyponatremia, with a mean serum sodium level of 115 ± 6 mmol/L (range, 101 to 125 mmol/L), and 3 patients had 2 or more episodes. Severe hyponatremia was a presenting sign in 0, 4.1, 14.3, and 37.5% of patients with craniopharyngiomas (n = 10), pituitary adenomas (n = 243), Rathke's cleft cysts (RCCs) (n = 21), and sellar arachnoid cysts (n = 8), respectively (P<.01). Half of the patients presenting with hyponatremia, including 6 of 10 patients with adenomas and 2 of 3 patients with RCCs, had pituitary apoplexy or cyst rupture. All patients had anterior pituitary gland dysfunction, including 81% with hypoadrenalism and 69% with hypothyroidism. Following surgery, hormonal status was unchanged or improved in 15 patients (median follow-up, 14 months). No patient had tumor/cyst recurrence or recurrent hyponatremia. CONCLUSION: Severe hyponatremia was a presenting sign in 5.7% of patients with sellar pathology, most frequently in patients with arachnoid cysts, RCCs, and pituitary apoplexy. Patients with new-onset severe hyponatremia and no obvious pharmacologic or systemic cause should undergo pituitary hormonal evaluation and brain imaging. Surgical resection and correction of hormonal deficiencies are associated with resolution of recurrent hyponatremic episodes.

Avoidance of postoperative epistaxis and anosmia in endonasal endoscopic skull base surgery: a technical note.

BACKGROUND: Most endoscopic transsphenoidal approaches jeopardize the sphenopalatine artery and septal olfactory strip (SOS), increasing the risk of postoperative anosmia and epistaxis while precluding the ability to raise pedicled nasoseptal flaps (NSF). We describe a bilateral "rescue flap" technique that preserves the mucosa containing the nasal-septal vascular pedicles and the SOS. This approach can reduce the risk of postoperative complications, including epistaxis and anosmia. METHODS: A retrospective analysis was conducted of all patients who underwent endoscopic transsphenoidal surgery with preservation of both sphenopalatine vascular pedicles and SOS. In a recent subset of patients, olfactory assessment was performed. RESULTS: Of 174 consecutive operations performed in 161 patients, bilateral preservation of the sphenopalatine vascular pedicle and SOS was achieved in 139 (80 %) operations, including 31 (22 %) with prior transsphenoidal surgery. Of the remaining 35 operations, 18 had a planned formal NSF and 17 had prior surgery or extensive lesions precluding use of this technique. Of pituitary adenomas, RCCs or sellar arachnoid cysts, 118 (94 %) underwent this approach, including 91 % of patients who had prior surgery. Preoperative olfaction function was maintained in 97 % of patients that were tested. None of the patients had postoperative arterial epistaxis. CONCLUSION: Preservation of bilateral sphenopalatine vascular pedicles and the SOS is feasible in over 90 % of patients undergoing endonasal endoscopic surgery for pituitary adenomas and RCCs. This approach, while not hindering exposure or limiting instrument maneuverability, preserves the nasoseptal vasculature for future NSF use if needed and appears to minimize the risks of postoperative arterial epistaxis and anosmia.

Bypass using V2-V3 segment of the vertebral artery as donor or recipient: technical nuances and results.

OBJECTIVE: Surgical revascularization (bypass) technique has been used to treat vascular diseases of the posterior circulation, including ischemia, aneurysms, and tumors encasing a major artery. We focused on procedures using the V2-V3 segment of the vertebral artery (VA) as either the donor or recipient of the bypass. We have described technical nuances developed over time and evaluated the surgical results of those cases. METHODS: Data on all patients who underwent bypasses using the V2-V3 segment were collected retrospectively from a prospectively maintained database. RESULTS: Twenty patients had bypasses using V2-V3 distal VA as either the donor (13) or recipient (7); 19 patients had an intervening graft and in 1 patient, the VA was used for reimplantation of the posterior inferior cerebellar artery. Except for 1 patient, who died during the perioperative period, the mean follow-up time for the rest of the patients was 24.7 months (range 1-72 months). One patient developed postoperative stroke. One radial artery graft occluded, and a redo saphenous vein graft also occluded in the same patient. All the other bypasses were patent without flow limitation at the latest follow-up. Fourteen patients had a modified Rankin Scale score of 2 or better at the latest follow-up, and 2 died of unrelated causes as the result of their tumors. CONCLUSIONS: The V2-V3 segment of the VA can be used both as a donor and a recipient for bypass surgery. Using the technical steps perfected over time, we are able to achieve surgical results with high rate of graft patency and good functional outcome in patients.

Cervical spinous process reconstruction.

Posterior neck deformity with an unsightly crater-like defect may result after cervicothoracic laminectomies. The authors present a new technique, spinous process reconstruction, to address this problem. A 64-year-old man presented with progressive quadriparesis secondary to cervical spondylotic myelopathy. Previously he had undergone multiple neck surgeries including cervicothoracic decompressive laminectomy. Postoperatively, he developed severe craniocervical spinal deformity and a large painful concave surgical defect in the neck. The authors performed craniocervical decompression and craniocervicothoracic instrumented stabilization. At the same time, cervicothoracic spinous process reconstruction was performed using titanium mesh to address the defect. Cervicothoracic decompressive laminectomy results in varying degrees of neck defect with resulting unsightly and an often painful surgical wound defect despite an appropriate multilayer closure. The presented spinous process reconstruction is a simple technique to address this problem with good clinical outcome.

Chemotherapy-induced regression of an adrenocorticotropin-secreting pituitary carcinoma accompanied by secondary adrenal insufficiency.

Purpose. Adrenocorticotropin- (ACTH-) secreting pituitary carcinomas are rare and require multimodality treatment. The aim of this study was to report the response to various therapies and discuss the potential development of secondary adrenal insufficiency with cytotoxic chemotherapy. Methods. This report describes a man with a large silent corticotroph adenoma progressing to endogenous hypercortisolism and metastatic ACTH-secreting pituitary carcinoma over a period of 14 years. Results. Seven years after initial presentation, progressive tumor enlargement associated with the development of hypercortisolism mandated multiple pituitary tumor debulking procedures and radiotherapy. Testing of the Ki-67 proliferation index was markedly high and he developed a hepatic metastasis. Combination therapy with cisplatin and etoposide resulted in a substantial reduction in tumor size, near-complete regression of his liver metastasis, and dramatic decrease in ACTH secretion. This unexpectedly resulted in symptomatic secondary adrenal insufficiency. Conclusions. This is the first reported case of secondary adrenal insufficiency after use of cytotoxic chemotherapy for metastatic ACTH-secreting pituitary carcinoma. High proliferative indices may be predictive of dramatic responses to chemotherapy. Given the potential for such responses, the development of secondary adrenal insufficiency may occur and patients should be monitored accordingly.

Expandable versus nonexpandable cages for thoracolumbar burst fracture.

BACKGROUND: Burst fractures account for more than half of all thoracolumbar fractures and are frequently associated with spine instability and neurological deficit. The anterior approach is favored when decompression of the spinal canal is necessary. We compare two commonly available struts used for anterior approach after corpectomy: expandable versus nonexpandable titanium cages. METHODS: We retrospectively evaluated 32 patients with acute thoracolumbar burst fractures treated by a single surgeon with a mean follow-up of 13 months. Half of the patients had nonexpandable cages placed (group 1) and the other half had expandable cages placed (group 2). Anterolateral plate/screw supplementation was used in all patients. Radiographs were reviewed to assess kyphosis correction and bony fusion. RESULTS: In group 1, the mean kyphotic angle before surgery was 20.5 degrees. Immediately after surgery, this angle improved to 6 degrees and was 8.5 degrees at final follow-up. In group 2, the mean kyphotic angle before surgery was 21.5 degrees. This angle improved to 4 degrees immediately after surgery and was 6.5 degrees at final follow-up. At the end of follow-up, 2 of 16 patients in group 1 demonstrated pseudoarthrosis, whereas no patients in group 2 showed any evidence of nonunion. No patient in either group experienced hardware failure or new neurological deficit. CONCLUSIONS: Anterior decompression and instrumented stabilization with either an expandable or nonexpandable cage is a safe and reliable surgical treatment option for unstable thoracolumbar burst fractures. Expandable cage enables greater immediate correction of kyphosis with good fusion rate.

Biomechanical analysis and review of lateral lumbar fusion constructs.

STUDY DESIGN: Biomechanical study and the review of literature on lumbar interbody fusion constructs. OBJECTIVE: To demonstrate the comparative stabilizing effects of lateral interbody fusion with various supplemental internal fixation options. SUMMARY OF BACKGROUND DATA: Lumbar interbody fusion procedures are regularly performed using anterior, posterior, and more recently, lateral approaches. The biomechanical profile of each is determined by the extent of resection of local supportive structures, implant size and orientation, and the type of supplemental internal fixation used. METHODS: Pure moment flexibility testing was performed using a custom-built 6 degree-of-freedom system to apply a moment of ±7.5 Nm in each motion plane, while motion segment kinematics were evaluated using an optoelectronic motion system. Constructs tested included the intact spine, stand-alone extreme lateral interbody implant, interbody implant with lateral plate, unilateral and bilateral pedicle screw fixation. These results were evaluated against those from literature-reported biomechanical studies of other lumbar interbody constructs. RESULTS: All conditions demonstrated a statistically significant reduction in range of motion (ROM) as a percentage of intact. In flexion-extension, ROM was 31.6% stand-alone, 32.5% lateral fixation, and 20.4% and 13.0% unilateral and bilateral pedicle screw fixation, respectively. In lateral bending, the trend was similar with greater reduction with lateral fixation than in flexion-extension; ROM was 32.5% stand-alone, 15.9% lateral fixation, and 21.6% and 14.4% unilateral and bilateral pedicle screw fixation. ROM was greatest in axial rotation; 69.4% stand-alone, 53.4% lateral fixation, and 51.3% and 41.7% unilateral and bilateral pedicle screw fixation, respectively. CONCLUSION: The extreme lateral interbody construct provided the largest stand-alone reduction in ROM compared with literature-reported ALIF and TLIF constructs. Supplemental bilateral pedicle screw-based fixation provided the overall greatest reduction in ROM, similar among all interbody approach techniques. Lateral fixation and unilateral pedicle screw fixation provided intermediate reductions in ROM. Clinically, surgeons may evaluate these comparative results to choose fixation options commensurate with the stability requirements of individual patients.