Author: cba

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Very Late Complications of Cervical Arthroplasty

Very Late Complications of Cervical Arthroplasty

Spine 2013;38:2223––2226

Prospective, single-site, randomized, Food and Drug Administration––approved investigational device exemption clinical trials of 2 cervical arthroplasty (CA) devices.

Objective. To evaluate complications with CA occurring more than 4 years after the surgical procedure in Food and Drug Administration clinical trials of the Bryan and Prestige LP arthroplasty devices. Summary of Background Data. Reports of several randomized clinical studies have shown CA to be a safe and effective alternative to anterior cervical fusion in the treatment of degenerative cervical disc disorders. A majority include follow-up intervals of 4 years or less.

Methods. Between 2002 and 2006, 94 patients were enrolled in Food and Drug Administration studies of the Bryan and Prestige LP cervical disc devices. Charts, imaging studies, and hospital records were reviewed for those who underwent arthroplasty and returned more than 4 years after their surgical procedure with neck-related pain or dysfunction. Results. Excluding adjacent segment disease that occurred with a similar rate for patients who underwent fusion and arthroplasty, 5 patients, all treated with arthroplasty, returned for evaluation of neck and arm symptoms between 48 and 72 months after surgery. Four patients had peridevice vertebral body bone loss. One patient had posterior device migration and presented with myelopathy. Three required revision surgery and 2 were observed. Four patients maintained follow-up and reported stabilization or improvement in symptoms.

Conclusion. Despite their similarities, CA and fusion are not equivalent procedures in this study in regard to very late complications. Similar to large joint arthroplasty, delayed devicerelated complications may occur with CA. These complications commenced well beyond the time frame for complications associated with more traditional cervical spine procedures. Both patients and surgeons should be aware of the potential for very late device-related complications occurring with CA and the need for revision surgery.

Level of Evidence: 1

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Keyhole Supracerebellar Transtentorial Transcollateral Sulcus Approach to the Lateral Ventricle

Keyhole Supracerebellar Transtentorial Transcollateral Sulcus Approach to the Lateral Ventricle

Neurosurgery 73[ONS Suppl 2]:onsE295–onsE301, 2013

Meningiomas of the lateral ventricles are commonly located in the atria. Surgical access to such tumors is challenging because of their deep location and proximity to critical neurovascular structures, particularly if situated on the dominant side. Although a number of approaches have been described in the literature, most carry the risk of postoperative neuropsychological, visual, or speech deficits, especially when operating on the dominant hemisphere. The supracerebellar transtentorial transcollateral sulcus (STTCS) approach offers the potential to circumvent functionally important structures, reducing the risk of these approach-related neurological deficits.

CLINICAL PRESENTATION: Two patients with dominant hemisphere trigonal meningiomas underwent surgical resection with the use of the STTCS approach. Neuronavigation was used to carefully plan the incision, craniotomy, and exposure, and also intraoperatively to orientate the operating surgeon at key steps, particularly when raising the tentorial flap in line with the tumor. Endoscopy was used to provide increased light intensity, an extended viewing angle, and higher magnification in comparison with a microscope. Specially designed tube-shaft instruments were also used to assist with manipulation through the narrow surgical corridor. In both cases, the tumors were fully resected without approach-related morbidity.

CONCLUSION: The STTCS approach provides good access to tumors located in the trigonal region, reducing the risk of iatrogenic language or visual field deficits. In dominant hemisphere lesions, in the hands of an experienced neurosurgeon, the STTCS approach is an effective alternative to existing techniques.

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Management and outcome of high-grade multicentric gliomas

Management and outcome of high-grade multicentric gliomas

Acta Neurochir (2013) 155:2245–2251

Multicentric malignant gliomas are wellseparated tumours in different lobes or hemispheres, without anatomical continuity between lesions. The purpose of this study was to explore the clinical features, the pathology and the outcome according to the management strategies in a consecutive series of patients treated at a single institution. In addition, an analysis of the existing literature is presented.

Methods For the institutional analysis, a retrospective review of all patients who underwent treatment for multicentric gliomas in the last 7 years was performed. For the analysis of the literature, a MEDLINE search with no date limitations was accomplished for surgical treatment of multicentric malignant gliomas.

Results Two hundred and thirty-nine patients with glioma were treated in our department. Eighteen patients (7.5%) with a mean age of 64 years (age range, 37–78 years) presented multicentric malignant gliomas. Thirteen patients (72 %) underwent surgical resection of at least one lesion that was followed by adjuvant treatment in all but one case. Five patients (28 %) underwent stereotactic biopsy and thereafter received chemotherapy. A survival advantage was associated with resection of at least one lesion followed by adjuvant treatment (median overall survival 12 months) compared with 4 months for stereotactic biopsy followed by chemotherapy. Similar results were obtained from the review of the literature.

Conclusions Resection of at least one lesion seems to play a significant role in the management of selected patients with multicentric malignant gliomas. Multi-institutional studies on larger series are warranted to define how aggressively the patients with malignant multicentric gliomas should be treated.

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Role of intraoperative neurophysiological monitoring during fluorescence-guided resection surgery

Role of intraoperative neurophysiological monitoring during fluorescence-guided resection surgery

Acta Neurochir (2013) 155:2201–2213

Fluorescence-guided resection (FGR) using 5- aminolevulinic acid (5-ALA) exhibits a potential risk of permanent neurological deficits that can be minimized using intraoperative neurophysiological monitoring (IONM). We assessed the role of IONM in FGR surgery in patients harboring tumors in or near eloquent areas.

Methods IONM and FGR surgeries were performed on 34 patients (49.8±2.4 years) harbored malignant primary gliomas near eloquent cortical areas or semioval center. Different combinations of neurophysiological techniques were used depending on each patient.

Results Gross total resection (GTR) was achieved in 66.7 % of the patients, mean 90.4±3.7 % without neurological deficits. Resection in four patients was stopped by the occurrence of severe warning criteria despite the presence of fluorescence. Hemispheric transcranial electrical stimulation was safe and confident even in cortical surgery. Notably, a significant percentage of patients exhibited clinical improvement after the surgery. One week after surgery, only one patient worsened, and seven patients improved. At 3 months, 27.8 % of the patients improved, and the other patients maintained a similar status to their pre-surgery condition.Warning common criteria (amplitude reduction and/or latency increase) appeared in 68.2 and 50.0 % of patients during cortical or semioval surgery, respectively, with neither a false-negative nor a false-positive clinical outcome. Although 5-ALA exhibits phototoxicity, VEP did not induce any secondary effects in the visual system, including eyelids.

Conclusions IONM can be helpful during surgery to maximize the tumor resection, meanwhile help to avoid neurological deficits and, therefore, to improve the quality of life of these patients.

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Effect of dural detachment on long-term tumor control for meningiomas treated using Simpson Grade IV resection

Effect of dural detachment on long-term tumor control for meningiomas treated using Simpson Grade IV resection

J Neurosurg 119:1373–1379, 2013

Meningiomas treated by subtotal or partial resection are associated with significantly shorter recurrencefree survival than those treated by gross-total resection. The Simpson grading system classifies incomplete resections into a single category, namely Simpson Grade IV, with wide variations in the volume and location of residual tumors, making it complicated to evaluate the achievement of surgical goals and predict the prognosis of these tumors. Authors of the present study investigated the factors related to necessity of retreatment and tried to identify any surgical nuances achievable with the aid of modern neurosurgical techniques for meningiomas treated using Simpson Grade IV resection.

Methods. This retrospective analysis included patients with WHO Grade I meningiomas treated using Simpson Grade IV resection as the initial therapy at the University of Tokyo Hospital between January 1995 and April 2010. Retreatment was defined as reresection or stereotactic radiosurgery due to postoperative tumor growth.

Results. A total of 38 patients were included in this study. Regrowth of residual tumor was observed in 22 patients with a mean follow-up period of 6.1 years. Retreatment was performed for 20 of these 22 tumors with regrowth. Risk factors related to significantly shorter retreatment-free survival were age younger than 50 years (p = 0.006), postresection tumor volume of 4 cm3 or more (p = 0.016), no dural detachment (p = 0.001), and skull base location (p = 0.016). Multivariate analysis revealed that no dural detachment (hazard ratio [HR] 6.42, 95% CI 1.41–45.0; p = 0.02) and skull base location (HR 11.6, 95% CI 2.18–218; p = 0.002) were independent risk factors for the necessity of early retreatment, whereas postresection tumor volume of 4 cm3 or more was not a statistically significant risk factor.

Conclusions. Compared with Simpson Grade I, II, and III resections, Simpson Grade IV resection includes highly heterogeneous tumors in terms of resection rate and location of the residual mass. Despite the difficulty in analyzing such diverse data, these results draw attention to the favorable effect of dural detachment (instead of maximizing the resection rate) on long-term tumor control. Surgical strategy with an emphasis on detaching the tumor from the affected dura might be another important option in resection of high-risk meningiomas not amenable to gross-total resection.

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Carotid Artery Injury During Endoscopic Endonasal Skull Base Surgery: Incidence and Outcomes

Carotid Artery Injury During Endoscopic Endonasal Skull Base Surgery- Incidence and Outcomes

Neurosurgery 73[ONS Suppl 2]:ons261–ons270, 2013

Injury to the internal carotid artery (ICA) during endoscopic endonasal skull base surgery is a feared complication that is not well studied or reported.

OBJECTIVE: To evaluate the incidence, to identify potential risk factors, and to present management strategies and outcomes of ICA injury during endonasal skull base surgery at our institution. METHODS: We performed a retrospective review of all endoscopic endonasal operations performed at our institution between 1998 and 2011 to examine potential factors predisposing to ICA injury. We also documented the perioperative management and outcomes after injury.

RESULTS: There were 7 ICA injuries encountered in 2015 endonasal skull base surgeries, giving an incidence of 0.3%. Most injuries (5 of 7) involved the left ICA, and the most common diagnosis was chondroid neoplasm (chordoma, chondrosarcoma; 3 of 7 [2% of 142 cases]). Two injuries occurred during 660 pituitary adenoma resections (0.3%). The paraclival ICA segment was the most commonly injured site (5 of 7), and transclival and transpterygoid approaches had a higher incidence of injury, although neither factor reached statistical significance. Four of 7 injured ICAs were sacrificed either intraoperatively or postoperatively. No patient suffered a stroke or neurological deficit. There were no intraoperative mortalities; 1 patient died postoperatively of cardiac ischemia. One of the 3 preserved ICAs developed a pseudoaneurysm over a mean follow-up period of 5 months that was treated endovascularly.

CONCLUSION: ICA injury during endonasal skull base surgery is an infrequent and manageable complication. Preservation of the vessel remains difficult. Chondroid tumors represent a higher risk and should be resected by surgical teams with significant experience.

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Three dimensional anatomy of the human nucleus accumbens

Three dimensional anatomy of the human nucleus accumbens

Acta Neurochir (2013) 155:2389–2398

The Nucleus accumbens (Acc) is the main structure of the ventral striatum. It acts as a motor-limbic interface, being involved in emotional and psychomotor functions, frequently disturbed in neuropsychiatric disorders such as obsessive compulsive disorder and addiction. Most of the studies concerning the Acc were made in animals and those performed in humans are contradictory. Nevertheless, it has become a target for stereotactic deep brain stimulation for some of those diseases, when refractory to medical treatment. Previous studies performed by our group have established the localization, limits and dimensions of the human Acc and its stereotactic coordinates. Now it is our purpose to perform the Acc anatomical three-dimensional (3D) reconstruction in order to clarify its shape and topography and to render this nucleus a safer target for stereotactic procedures.

Methods Anatomical coronal slicing of ten Acc from human brains was performed, perpendicular to the anterior commissure-posterior commissure line and to the midline; then the Acc contours were traced and its dimensions and 3D stereotactic coordinates measured, on each slice. Finally a 3D computerized model was created.

Results The human Acc was identified as a distinct brain structure, with clear-cut limits on its posterior half. It lies parallel to the midline, descends caudally, and progresses from a globose to a flattened and dorsolateral concave shape. Its main expression is subcomissural.

Conclusion This study defined more accurately the 3D anatomy of the human Acc, providing new tools for stereotactic procedures.

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Long-term Follow-up of Blister Aneurysms of the Internal Carotid Artery

Blister ICA aneurysm

Neurosurgery 73:1026–1033, 2013

Blister aneurysms of the internal carotid artery (ICA) are uncommon. There is a paucity of data on the long-term outcomes of patients.

OBJECTIVE: To review our experience with the treatment of these lesions.

METHODS: We retrospectively reviewed all aneurysms treated at our institution between 1994 and 2005. Relevant operative notes, radiology reports, and inpatient/ outpatient records were reviewed.

RESULTS: Seventeen patients (3 male, 14 female) with 18 blister aneurysms of the ICA were identified. The mean age was 44.6 years (range, 17-72; median, 42 years). Twelve patients (70.6%) presented with aneurysmal subarachnoid hemorrhage. The mean admission Glasgow Outcome Scale score was 4.3 (range, 2-5; median, 5). All patients were initially treated using microsurgical technique with direct clipping (n = 15; 83.3%) or clip-wrapping with Gore-Tex (n = 3, 16.7%). There were 4 cases of intraoperative rupture, all associated with attempted direct clipping; all 4 cases were successfully clipped. Two cases rebled post-treatment. Both rebleeding episodes were managed with endovascular stenting. Follow-up angiography was available for 14 patients and revealed a new aneurysm adjacent to the site of clipping in 1 patient and in-stent stenosis in 2. At the mean follow-up of 74.5 months (median, 73; range, 7-165), the mean Glasgow Outcome Scale score was 4.6 (range, 2-5; median, 5).

CONCLUSION: Microsurgical treatment of blister aneurysms of the ICA results in excellent outcome. In the evolution of treating these friable aneurysms, we have modified our clip-wrapping technique and use this technique when direct clipping is not feasible.

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Long-term follow-up of standard microdiscectomy versus minimal access surgery for lumbar disc herniations

Long-term follow-up of standard microdiscectomy versus minimal access surgery for lumbar disc herniations

Acta Neurochir (2013) 155:2333–2338

Surgery of lumbar disc herniations is one of the most common neurosurgical procedures. New surgical approaches and techniques are constantly evolving. We present our long-term follow-up results comparing standard open microdiscectomy (SOMD) andminimal access microdiscectomy (MAMD) for single-level lumbar disc herniations.

Methods Patients were randomized in two groups receiving eitherMAMDor SOMD. Physical and mental health and pain relief were assessed (ODI, SF-36 questionnaire, VAS leg and back pain). In addition, all patients received MR imaging for morphological evaluation of postoperative peridural scar tissue formation.

Results Of the 60 initial patients (SOMD: 30 pts, MAMD: 30 pts), 38 were available for long-term follow-up. Mean follow-up time was 33 months. Long-term follow-up revealed significant postoperative pain relief in both groups. Good to excellent results concerning physical and mental health and pain relief were achieved in both groups. Significantly less peridural scar tissue formation was observed in the MAMD patients, but without clinical impact.

Conclusion MAMD is a feasible alternative to the standard open approach. Both groups show significant and long-lasting pain relief and good to excellent results regarding healthrelated quality of life. Congruent to our short-term results, we observed slightly but not statistically significant better clinical results in the MAMD group when compared to the SOMD group.

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The Aqueduct of Sylvius: Applied 3-T Magnetic Resonance Imaging Anatomy and Morphometry With Neuroendoscopic Relevance

Aqueduct of Sylvius MRI morphometry

Neurosurgery 73[ONS Suppl 2]:ons132–ons140, 2013

The aqueduct of Sylvius (AqSylv) is a structure of increasing importance in neuroendoscopic procedures. However, there is currently no clear and adequate description of the normal anatomy of the AqSylv.

OBJECTIVE: To study in detail hitherto unavailable normal magnetic resonance imaging morphometry and anatomic variants of the AqSylv.

METHODS: We retrospectively studied normal midsagittal T1-weighted 3-T magnetic resonance images in 100 patients. We measured widths of the AqSylv pars anterior, ampulla, and pars posterior; its narrowest point; and its length. We recorded angulation of the AqSylv relative to the third ventricle as multiple deviations of the long axis of the AqSylv from the Talairach bicommissural line. We statistically determined age- and sexrelated changes in AqSylv morphometry using the Pearson correlation coefficient. We measured angulation of the AqSylv relative to the fourth ventricle and correlated this to the cervicomedullary angle (a surrogate for head position).

RESULTS: Patients were 13 to 83 years of age (45% male, 55% female). Mean morphometrics were as follows: pars anterior width, 1.1 mm; ampulla width, 1.2 mm; pars posterior width, 1.4 mm; length, 14.1 mm; narrowest point, 0.9 mm; and angulation in relation to the third and fourth ventricles, 26 and 18, respectively. Age correlated positively with width and negatively with length of the AqSylv. There was no correlation between AqSylv alignment relative to the foramen magnum and the cervicomedullary angle.

CONCLUSION: Normative dimensions of the AqSylv in vivo are at variance with published cadaveric morphometrics. The AqSylv widens and shortens with cerebral involution. Awareness of these normal morphometrics is highly useful when stent placement is an option during aqueductoplasty. Reported data are valuable in guiding neuroendoscopic management of hydrocephalus and aqueductal stenosis.

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Hypertensive slit ventricle syndrome: pseudotumor cerebri with a malfunctioning shunt?

slit ventricles

J Neurosurg 119:1503–1510, 2013

Symptomatic shunt malfunction without ventricular enlargement is known as slit ventricle syndrome (SVS). Patients presenting with this syndrome are not a homogeneous group. Of the 5 different types classified by Rekate, Type 1 is caused by CSF overdrainage and is associated with low pressures; Types 2 and 3 are associated with shunt blockage and elevated CSF pressures; Type 4 is cephalocranial disproportion that increases brain parenchymal pressure but not CSF pressure; and Type 5 is headache unrelated to shunt function. The low and normal CSF pressure types are relatively well understood, but the high-pressure forms are more problematic. In the high-pressure forms of SVS it is said that the lack of ventricular dilation is related to a reduction in brain compliance analogous to idiopathic intracranial hypertension or pseudotumor cerebri. Despite this, there is little evidence in the literature to support this conjecture.

With this in mind, 3 cases of SVS associated with elevated CSF pressure are presented. The MR venogram findings and hemodynamics of these 3 cases are shown to be identical to those of pseudotumor cerebri. A literature review indicates that an underlying venous impairment may be functioning in the patients who re-present with small ventricles following shunt malfunction.

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Bilateral stereotactic anterior capsulotomy for obsessive-compulsive disorder: long-term follow-up

DBS-OCD

J Neurol Neurosurg Psychiatry 2013;84:1208–1213

Psychosurgery, such as anterior capsulotomy, is a therapeutic option for treatment-resistant obsessive-compulsive disorder (OCD). In this paper, we present a prospective, long-term follow-up study aimed at evaluating both the efficacy and the safety of anterior capsulotomy for the treatment of severe, refractory OCD.

Methods Twenty-four patients were surgically treated in our centre between 1997 and 2009, 19 of whom were included in this study. Patients were assessed at 3, 6, 12, and 24 months and last follow-up (mean of 7 years) was carried out by phone. OCD symptom severity was evaluated using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). A patient with an improvement rate of over 35% in the Y-BOCS score was considered a responder, while a patient with a 25% improvement was considered a partial responder.

Results With a mean improvement of 31% in the Y-BOCS score at long-term follow-up, 36.8% of the patients responded fully to the procedure and 10.5% were considered partial responders, for an overall response rate of 47.3% of patients. At the end of the study, 3/19 patients had recovered (Y-BOCS score <8) and 3/19 were in remission (Y-BOCS score <16). No cases of mortality were reported and the overall adverse event rate was 57.9%. Only 2 patients had permanent surgical complications.

Conclusions Anterior capsulotomy is an effective and safe technique for the treatment of severe refractory OCD in patients who have no other alternative to improve their symptoms.

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Recurrent high-grade glioma treated with bevacizumab: prognostic value of MGMT methylation, EGFR status and pretreatment MRI in determining response and survival

Recurrent GBM and bevacizumab

J Neurooncol (2013) 115:267–276

Although bevacizumab represented an important advance in treatment of recurrent high-grade gliomas (HGG), responses occur in fewer than half of patients. There are no validated biomarkers for anti-angiogenic therapy that are available for routine clinical use.

We assessed the prognostic values of imaging and molecular markers in this patient population. MRI scans from 191 patients with recurrent HGG obtained prior to initiating bevacizumab were reviewed for areas of enhancement, necrosis, T2/FLAIR abnormality, and ADC values. Serial MRI scans following the initiation of bevacizumab were evaluated for response and progression. Non-radiographic markers including EGFR and MGMT status were also assessed with respect to response and patient survival.

65 of 191 patients (34 %) showed complete or partial response at the time of their best response MRI and demonstrated longer progression free survival (PFS) and overall survival (OS) compared to the group without response (PFS: 6.9 vs 3.5 months, OS: 10.9 vs 6.1 months). Minimum ADC values within enhancing and non-enhancing regions were lower in responders compared to those of nonresponders (1,099 vs 984 x 10-6 mm2/s, p = 0.006). Smaller enhancing area was associated with longer OS (HR = 1.99, p = 0.017). The ratio of T2/FLAIR to enhancing area was prognostic of OS for only the Grade III HGG subgroup (HR = 0.14, p = 0.004).

Area of enhancing tumor at baseline can stratify survival in patients with recurrent HGG treated with bevacizumab. The extent of edema relative to enhancing area may have a prognostic role specific to Grade III HGG.

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Delayed Neurological Deterioration After Mild Head Injury: Cause, Temporal Course, and Outcomes

acutesdh

Neurosurgery 73:753–760, 2013

Mild head injury (MHI) complicated by an intracranial hemorrhage (ICH) is a common cause of hospital admission after head trauma. Most patients are treated nonoperatively, remain neurologically stable, and are discharged uneventfully. However, a small percentage of patients suffer delayed neurological deterioration (DND). Little is known about the characteristics of DND after an MHI complicated by ICH.

OBJECTIVE: To identify the cause, temporal course, and outcomes of patients who deteriorated neurologically after presenting with MHI and ICH. METHODS: A retrospective review was performed of all adult patients presenting over 54 consecutive months with MHI and ICH. Patients who were treated nonoperatively after initial head computed tomography and had a subsequent DND (Glasgow Coma Scale score decrease $2) were identified. Demographics, neurological status, clinical course, radiographic findings, and outcome data were collected.

RESULTS: Over 54 months, 757 patients with MHI plus ICH were admitted for observation; of these, 31 (4.1%) experienced DND. Eighty-seven percent of patients deteriorated within 24 hours after admission. Twenty-one patients (68%) deteriorated as a result of progressive intracranial hemorrhage, and 10 patients (32%) deteriorated as a result of medical causes. Seven patients (23%) died. Variables significantly associated with mortality included age . 60 years, coagulopathy, and change in Marshall computed tomography classification.

CONCLUSION: The incidence of delayed neurological deterioration after MHI with ICH is low and usually occurs within 24 hours after admission. It results in significant morbidity and mortality if it is the result of progressive intracranial hemorrhage. Further research is needed to identify risk factors that can allow early detection and improve outcomes in these patients.

KEY WORDS:

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Chiari I malformation associated with syringomyelia: can foramen magnum decompression lead to restore cervical alignment?

Chiari I malformation associated with syringomyelia- can foramen magnum decompression lead to restore cervical alignment?

Eur Spine J (2013) 22:2520–2525

There are few researches that demonstrate the relationship between the extent of syringomyelia and sagittal alignment of the cervical spine. The purpose of this study is to investigate the correlation between the change of syrinx size and cervical alignment.

Methods From January 2001 to June 2008, we operated on 207 patients who had syringomyelia. The associated diseases were categorized by Chiari I malformation, tumor, trauma, spinal stenotic lesion, inflammatory disease and idiopathic causes. Thirty patients who had Chiari I malformation associated with syringomyelia and who underwent foramen magnum decompression (FMD), participated in this study. We excluded patients with scoliosis, cervical instrumentation, tumor, trauma, myelomeningocele, hydrocephalus, tethered cord and congenital vertebral anomalies. Lateral radiographs in neutral and magnetic resonance imaging were taken pre- and postoperatively.

Results Mean follow-up was 6.5 ± 1.5 years (ranged from 4.0 to 9.5 years). The mean pre- and postoperative lordosis angles at C2–C7 were −5.9° ± 1.0° and −10.4° ± 1.0°, respectively (P = 0.001). There was significant correlation between the differences of syrinx width and the cervical lordotic angles before and after surgery (P = 0.016). After FMD, syringomyelia and cervical alignment improved in 28 (93.3 %) and 25 (85.18 %) of 30 patients, respectively. There was significant correlation between recovery rate by Japanese Orthopaedic Association scores and the difference of the cervical lordotic angles before and after surgery (P = 0.022).

Conclusions The present results demonstrate that the decrease of syrinx size by FMD may restore the cervical lordosis. We suggest that the postoperative cervical alignment might be a predictive factor for neurological outcome.

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Management of subdural hygromas associated with arachnoid cysts

Subdural hygromas associated with cysts

J Neurosurg Pediatrics 12:434–443, 2013

Arachnoid cysts may occasionally be associated with subdural hygromas. The management of these concurrent findings is controversial.

Methods. The authors reviewed their experience with arachnoid cysts and identified 8 patients with intracranial arachnoid cysts and an associated subdural hygroma. The medical records and images for these patients were also examined.

Results. In total, 8 patients presented with concurrent subdural hygroma and arachnoid cyst. Of these 8 patients, 6 presented with headaches and 4 had nausea and vomiting. Six patients had a history of trauma. One patient was treated surgically at the time of initial presentation, and 7 patients were managed without surgery. All patients experienced complete resolution of their presenting signs and symptoms.

Conclusions. Subdural hygroma may lead to symptomatic presentation for otherwise asymptomatic arachnoid cysts. The natural course of cyst-associated subdural hygromas, even when symptomatic, is generally benign, and symptom resolution can be expected in most cases. The authors suggest that symptomatic hygroma is not an absolute indication for surgical treatment and that expectant management can result in good outcomes in many cases.

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The human foramen magnum—normal anatomy of the cisterna magna in adults

The human foramen magnum type A

Neuroradiology (2013) 55:1333–1339

The goal of this study was to radiologically describe the anatomical characteristics of the cisterna magna (CM) with regard to presence, dimension, and configuration.

Methods In this retrospective study, 523 records were reviewed. We defined five CM types, the range of which covered all normal variants found in the study population. Characteristics of the CM were recorded and correlations between various posterior fossa dimensions and CM volume determined.

Results There were 268 female (mean age 50.9±16.9 years) and 255 male (mean age 54.1±15.8 years) patients. CMvolume was smaller in females than in males and correlated with age (Pearson correlation, r =0.1494, p =0.0006) and gender (unpaired t test, r2=0.0608, p <0.0001). Clivus length correlated with CM volume (Pearson correlation, r =0.211, p <0.0001) and gender (unpaired t test, r2=0.2428, p <0.0001). Tentorial angle did not correlate with CM volume (Pearson correlation, r =−0.0609, p <0.1642) but did correlate with gender (unpaired t test, r2=0.0163, p <0.0035). The anterior–posterior dimension of cerebrospinal fluid anterior to the brainstem correlated with CM volume (Pearson correlation, r =0.181, p <0.0001) and gender (unpaired t test, r2=0.0205, p =0.001).

Conclusion The anatomical description and simple classification system we define allows for a more precise description of posterior fossa anatomy and could potentially contribute to the understanding of Chiari malformation anatomy and management.

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The A1-A2 Diameter Ratio May Influence Formation and Rupture Potential of Anterior Communicating Artery Aneurysms

AComAA

Neurosurgery 73:845–853, 2013

Specific morphological factors contribute to the hemodynamics of the anterior communicating artery (AComA). No study has examined the role of the A2 segment on AComA aneurysm presence and rupture.

OBJECTIVE: To examine the possibility that the ratio between A1 and A2 segments (A1-2 ratio) represents an independent risk factor for presence and rupture of AComA aneurysms (AComAAs).

METHODS: A retrospective review of an institutional aneurysm database was performed; patients with ruptured and unruptured AComAAs were identified. Two control groups were selected: group A (posterior circulation aneurysms) and group B (patients without intracranial aneurysms or other vascular malformations). Measurements of A1 and A2 diameters were obtained from digital subtraction angiography (64.1% of 3-D rotational digital subtraction angiography), and the A1-2 ratio calculated.

RESULTS: From January 2009 to April 2011, 156 patients were identified (52 AComAAs, 54 control group A, and 50 control group B). Mean age at the time of presentation was 56.09 years. Compared with both control groups, patients with AComAAs had greater A1 diameter (P < .01) and A1-2 ratio (P < .001) and smaller A2 diameter (P < .01). The A1-2 ratio correlated positively with the presence of AComAAs (P < .001). Ruptured AComAAs were smaller than unruptured ones (5.91 mm vs 9.25 mm, P = .02) and associated with a higher A1-2 Ratio (P = .02). The presence of a dominant A1 did not predict AComAA rupture (P = .15). The A1-2 ratio correlated positively with the presence of ruptured AComAAs (P = .04).

CONCLUSION: A1-2 ratio correlates positively with the presence and rupture of AComAAs and may facilitate treatment decision in cases of small, unruptured AComAAs.

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Cost-effectiveness analysis: comparing single-level cervical disc replacement and single-level anterior cervical discectomy and fusion

CDR

J Neurosurg Spine 19:546–554, 2013

In recent years, there has been increased interest in the use of cervical disc replacement (CDR) as an alternative to anterior cervical discectomy and fusion (ACDF). While ACDF is a proven intervention for patients with myelopathy or radiculopathy, it does have inherent limitations. Cervical disc replacement was designed to preserve motion, avoid the limitations of fusion, and theoretically allow for a quicker return to activity. A number of recently published systematic reviews and randomized controlled trials have demonstrated positive clinical results for CDR, but no studies have revealed which of the 2 treatment strategies is more cost-effective. The purpose of this study was to evaluate the cost-effectiveness of CDR and ACDF by using the power of decision analysis. Additionally, the authors aimed to identify the most critical factors affecting procedural cost and effectiveness and to define thresholds for durability and function to focus and guide future research.

Methods. The authors created a surgical decision model for the treatment of single-level cervical disc disease with associated radiculopathy. The literature was reviewed to identify possible outcomes and their likelihood following CDR and ACDF. Health state utility factors were determined from the literature and assigned to each possible outcome, and procedural effectiveness was expressed in units of quality-adjusted life years (QALYs). Using ICD-9 procedure codes and data from the Nationwide Inpatient Sample, the authors calculated the median cost of hospitalization by multiplying hospital charges by the hospital-specific cost-to-charge ratio. Gross physician costs were determined from the mean Medicare reimbursement for each current procedural terminology (CPT) code. Uncertainty as regards both cost and effectiveness numbers was assessed using sensitivity analysis.

Results. In the reference case, the model assumed a 20-year duration for the CDR prosthesis. Cervical disc replacement led to higher average QALYs gained at a lower cost to society if both strategies survived for 20 years ($3042/QALY for CDR vs $8760/QALY for ACDF). Sensitivity analysis revealed that CDR needed to survive at least 9.75 years to be considered a more cost-effective strategy than ACDF. Cervical disc replacement becomes an acceptable societal strategy as the prosthesis survival time approaches 11 years and the $50,000/QALY gained willingness-to-pay threshold is crossed. Sensitivity analysis also indicated that CDR must provide a utility state of at least 0.796 to be cost-effective.

Conclusions. Both CDR and ACDF were shown to be cost-effective procedures in the reference case. Results of the sensitivity analysis indicated that CDR must remain functional for at least 14 years to establish greater costeffectiveness than ACDF. Since the current literature has yet to demonstrate with certainty the actual durability and long-term functionality of CDR, future long-term studies are required to validate the present analysis.

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Endoscopic endonasal surgery for craniopharyngiomas: surgical outcome in 64 patients

Endoscopic endonasal surgery for craniopharyngiomas

J Neurosurg 119:1194–1207, 2013

The proximity of craniopharyngiomas to vital neurovascular structures and their high recurrence rates make them one of the most challenging and controversial management dilemmas in neurosurgery. Endoscopic endonasal surgery (EES) has recently been introduced as a treatment option for both pediatric and adult craniopharyngiomas. The object of the present study was to present the results of EES and analyze outcome in both the pediatric and the adult age groups.

Methods. The authors retrospectively reviewed the records of patients with craniopharyngioma who had undergone EES in the period from June 1999 to April 2011.

Results. Sixty-four patients, 47 adults and 17 children, were eligible for this study. Forty-seven patients had presented with primary craniopharyngiomas and 17 with recurrent tumors. The mean age in the adult group was 51 years (range 28–82 years); in the pediatric group, 9 years (range 4–18 years). Overall, the gross-total resection rate was 37.5% (24 patients); near-total resection (> 95% of tumor removed) was 34.4% (22 patients); subtotal resection (≥ 80% of tumor removed) 21.9% (14 patients); and partial resection (< 80% of tumor removed) 6.2% (4 patients). In 9 patients, EES had been combined with radiation therapy (with radiosurgery in 6 cases) as the initial treatment. Among the 40 patients (62.5%) who had presented with pituitary insufficiency, pituitary function remained unchanged in 19 (47.5%), improved or normalized in 8 (20%), and worsened in 13 (32.5%). In the 24 patients who had presented with normal pituitary function, new pituitary deficit occurred in 14 (58.3%). Nineteen patients (29.7%) suffered from diabetes insipidus at presentation, and the condition developed in 21 patients (46.7%) after treatment. Forty-four patients (68.8%) had presented with impaired vision. In 38 (86.4%) of them, vision improved or even normalized after surgery; in 5, it remained unchanged; and in 1, it temporarily worsened. One patient without preoperative visual problems showed temporary visual deterioration after treatment. Permanent visual deterioration occurred in no one after surgery. The mean follow-up was 38 months (range 1–135 months). Tumor recurrence after EES was discovered in 22 patients (34.4%) and was treated with repeat surgery (6 patients), radiosurgery (1 patient), combined repeat surgery and radiation therapy (8 patients), interferon (1 patient), or observation (6 patients). Surgical complications included 15 cases (23.4%) with CSF leakage that was treated with surgical reexploration (13 patients) and/or lumbar drain placement (9 patients). This leak rate was decreased to 10.6% in recent years after the introduction of the vascularized nasoseptal flap. Five cases (7.8%) of meningitis were found and treated with antibiotics without further complications. Postoperative hydrocephalus occurred in 7 patients (12.7%) and was treated with ventriculoperitoneal shunt placement. Five patients experienced transient cranial nerve palsies. There was no operative mortality.

Conclusions. With the goal of gross-total or maximum possible safe resection, EES can be used for the treatment of every craniopharyngioma, regardless of its location, size, and extension (excluding purely intraventricular tumors), and can provide acceptable results comparable to those for traditional craniotomies. Endoscopic endonasal surgery is not limited to adults and actually shows higher resection rates in the pediatric population.

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