Author: cba

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The Craniovertebral Junction Area and the Role of the Ligaments and Membranes

Neurosurgery 68:291–301, 2011 DOI: 10.1227/NEU.0b013e3182011262

Traumatic injuries of the craniovertebral junction (CVJ) area are common and frequently the outcome of motor vehicle accidents, falls, and diving accidents.

To define and characterize CVJ traumatic injuries, some international classifications are currently in use, and they are thought and focused on junction bone fracture. However, recent data point out a major important role of the CVJ ligaments and membranes in traumatic injuries with a secondary function of the osseous structures.

Emphasizing the correct role of the ligaments and membranes is extremely important for determining appropriate medical or surgical planning for patients and also to design new CVJ injury classifications.

We reviewed every recent major publication on the ligaments and membranes of the CVJ area. We divided the information into sections concerning anatomy, embryology, biomechanics, trauma, and CVJ bone fractures.

A role of the ligaments and membranes in the traumatic injuries of the CVJ area has often been recognized; but only recently, with the increase in the knowledge of the anatomic and biomechanical junction area, supported by neuroradiological tools (magnetic resonance imaging) and a more detailed traumatic injuries assessment, has the role of the ligaments and membranes been highlighted.

Ligaments and membranes have a pivotal role in each junctional ability and are the key to orienting any medical or surgical indications in this unique area of the spine.

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Development of Stereotactic Mass Spectrometry for Brain Tumor Surgery

Neurosurgery 68:280–290, 2011 DOI: 10.1227/NEU.0b013e3181ff9cbb

Surgery remains the first and most important treatment modality for the majority of solid tumors. Across a range of brain tumor types and grades, postoperative residual tumor has a great impact on prognosis. The principal challenge and objective of neurosurgical intervention is therefore to maximize tumor resection while minimizing the potential for neurological deficit by preserving critical tissue.

OBJECTIVE: To introduce the integration of desorption electrospray ionization mass spectrometry into surgery for in vivo molecular tissue characterization and intraoperative definition of tumor boundaries without systemic injection of contrast agents.

METHODS: Using a frameless stereotactic sampling approach and by integrating a 3-dimensional navigation system with an ultrasonic surgical probe, we obtained image-registered surgical specimens. The samples were analyzed with ambient desorption/ ionization mass spectrometry and validated against standard histopathology. This new approach will enable neurosurgeons to detect tumor infiltration of the normal brain intraoperatively with mass spectrometry and to obtain spatially resolved molecular tissue characterization without any exogenous agent and with high sensitivity and specificity.

RESULTS: Proof of concept is presented in using mass spectrometry intraoperatively for real-time measurement of molecular structure and using that tissue characterization method to detect tumor boundaries. Multiple sampling sites within the tumor mass were defined for a patient with a recurrent left frontal oligodendroglioma, World Health Organization grade II with chromosome 1p/19q codeletion, and mass spectrometry data indicated a correlation between lipid constitution and tumor cell prevalence.

CONCLUSION: The mass spectrometry measurements reflect a complex molecular structure and are integrated with frameless stereotaxy and imaging, providing 3-dimensional molecular imaging without systemic injection of any agents, which can be implemented for surgical margins delineation of any organ and with a rapidity that allows real-time analysis.

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Lumbar total disc replacement from an extreme lateral approach: clinical experience with a minimum of 2 years’ follow-up

J Neurosurg Spine 14:38–45, 2011. (DOI: 10.3171/2010.9.SPINE09865)

Current lumbar total disc replacement (TDR) devices require an anterior approach for implantation. This approach has inherent limitations, including risks to abdominal structures and the need for resection of the anterior longitudinal ligament (ALL). Placement of a TDR device from a true lateral (extreme lateral interbody fusion [XLIF]) approach is thought to offer a less invasive option to access the disc space, preserving the stabilizing ligaments and avoiding scarring of anterior vasculature. In this study, the authors attempted to quantify the clinical and radiographic outcomes of a lateral approach to lumbar TDR from a prospective, single-center experience.

Methods. A TDR device designed for implantation through a true lateral, retroperitoneal, transpsoas approach (XLIF) was implanted in 36 patients with discography-confirmed 1- or 2-level degenerative disc disease. Clinical (pain and function) and radiographic (range of motion [ROM]) data were prospectively collected preoperatively, postoperatively, and serially for a minimum of 24 months’ follow-up.

Results. Thirty-six surgeries were performed in 16 men and 20 women (mean age 42.6 years). Surgeries included 15 single-level TDR procedures at L3–4 or L4–5, three 2-level TDR procedures spanning L3–4 and L4–5, and 18 hybrid procedures (anterior lumbar interbody fusion [ALIF]) at L5–S1 and TDR at L4–5 [17] or L3–4 [1]). Operative time averaged 130 minutes, with an average blood loss of 60 ml and no intraoperative complications. Postoperative radiographs showed good device placement. All patients were walking within 12 hours of surgery and all but 9 were discharged the next day (7 of 9 had hybrid TDR/ALIF procedures). Five patients (13.8%) had psoas weakness and 3 (8.3%) had anterior thigh numbness postoperatively, both resolving within 2 weeks. One patient (2.8%) demonstrated weakness of the leg ipsilateral to the approach side, which lasted through the 3-month visit but was resolved by the 6-month visit. One patient (2.8%) was found to have hypertrophy of the quadriceps contralateral to the approach side at the 12-month visit, which was resolved by the 2-year visit. Four patients (11%) had postoperative facet joint pain, all in hybrid cases. All patients were 2 years or more postsurgery as of this writing, although 3 were lost to follow-up between the 1- and 2-year visits. In 2 cases (5.6%), removal of the TDR device and revision to fusion were required due to unresolved pain. At 2 years’ follow-up, the average visual analog scale and Oswestry Disability Index scores had improved 69.6% and 61.4%, respectively, and ROM averaged 8.6°, well within physiological norms.

Conclusions. Long-term results of a laterally placed TDR device demonstrate maintenance of pain relief and functional improvement. The benefits of this technique—minimal morbidity, avoiding mobilization of the great vessels, preserving the ALL, biomechanically stable orientation, and broader revision options—suggest a promising new direction for TDR procedures.

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Ruptured anterior paraclinoid aneurysms

Neurosurg Rev (2011) 34:49–55. DOI 10.1007/s10143-010-0272-7

The purpose of this study was to evaluate cases of subarachnoid hemorrhage (SAH) from ruptured anterior (dorsal) paraclinoid aneurysms. Anterior paraclinoid aneurysms are defined as aneurysms arising from the anterolateral wall of the proximal internal carotid artery without any relationship to an arterial branch.

Between 1991 and 2008, a total of 159 patients with 169 paraclinoid aneurysms were treated at the Shinshu University Hospital and its affiliated hospitals. A retrospective analysis was carried out using charts, operation records, operation videos, and neuroimagings. Twenty six patients had anterior paraclinoid aneurysm. Six patients presented with SAH. Three aneurysms were saccular and the others were blister-like aneurysms based on operative findings. Neck laceration or premature rupture frequently happened during the clipping surgery even though the aneurysm was saccular type.

The treatment of a ruptured anterior paraclinoid aneurysm is quite difficult. Trapping and bypass would be recommended for such fragile aneurysms.

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Dural tears in percutaneous endoscopic lumbar discectomy

Eur Spine J (2011) 20:58–64. DOI 10.1007/s00586-010-1493-8

The objective of the study was to demonstrate the clinical characteristics of dural tears during percutaneous endoscopic lumbar discectomy (PELD) and to discuss how to prevent this unintended complication.

The study used data from 816 consecutive patients who underwent PELD between 2003 and 2007. A total of nine patients (1.1%) experienced symptomatic dural tears. The clinical outcomes were evaluated using the visual analogue scale (VAS), the Oswestry disability index (ODI), and modified MacNab criteria. Intractable radicular pain was the most common symptom, while classical manifestations, such as CSF leakage or wound swelling, were rare. In three of the nine cases, the dural tears were detected intraoperatively, while the remaining six cases were not recognized during the procedure. Among the unrecognized patients, two patients were found with nerve root herniation causing profound neurological deficits. All patients were managed by secondary open repair surgeries. The mean follow-up period was 30.8 months. The mean VAS of radicular leg pain improved from 8.3 to 2.6, and that of back pain improved from 4.1 to 2.6. The mean ODI improved from 69.6 to 29.2%. The final outcomes were excellent in one, good in five, fair in one, and poor in two patients. As application of the endoscopic procedure has been broadened to more complex cases, the risk of dural tears may increase.

Unrecognized dural tear with nerve root herniation may cause permanent neurological sequelae. Accurate information and proper technical considerations are essential to prevent this unpredictable complication.

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Evaluation of the ShuntCheck Noninvasive Thermal Technique for Shunt Flow Detection in Hydrocephalic Patients

Neurosurgery 68:198–205, 2011 DOI: 10.1227/NEU.0b013e3181fe2db6

ShuntCheck (Neuro Diagnostic Devices, Inc., Trevose, Pennsylvania) is a new device designed to detect cerebrospinal fluid (CSF) flow in a shunt by sensing skin temperature downstream from a region of CSF cooled by an ice cube.

OBJECTIVE: To understand its accuracy and utility, we evaluated the use of this device during routine office visits as well as during workup for suspected shunt malfunction.

METHODS: One hundred shunted patients were tested, including 48 evaluated during possible shunt malfunction, of whom 24 went on to surgical exploration. Digitally recorded data were blindly analyzed and compared with surgical findings and clinical follow-up.

RESULTS: Findings in the 20 malfunctioning shunts with unambiguous flow or absence of flow at surgery were strongly correlated with ShuntCheck results (sensitivity and specificity to flow of 80% and 100%, respectively, P = .0007, Fisher’s exact test, measure of agreement k = 0.8). However, the thermal determination did not distinguish patients in the suspected malfunction group who received surgery from those who were discharged without surgery (P = .248 by Fisher’s exact test, k = 0.20). Half of the patients seen in routine office visits did not have detectable flow, although none required shunt revision on clinical grounds. Intermittent flow was specifically demonstrated in one subject who had multiple flow determinations.

CONCLUSION: Operative findings show that the technique is sensitive and specific for detecting flow, but failure to detect flow does not statistically predict the need for surgery. A better understanding of the normal dynamics of flow in individual patients, which this device may yield, will be necessary before the true clinical utility of noninvasive flow measurement can be assessed.

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Does minimally invasive lumbar disc surgery result in less muscle injury than conventional surgery? A randomized controlled trial

Eur Spine J (2011) 20:51–57. DOI 10.1007/s00586-010-1482-y

The concept of minimally invasive lumbar disc surgery comprises reduced muscle injury. The aim of this study was to evaluate creatine phosphokinase (CPK) in serum and the cross-sectional area (CSA) of the multifidus muscle on magnetic resonance imaging as indicators of muscle injury.

We present the results of a double-blind randomized trial on patients with lumbar disc herniation, in which tubular discectomy and conventional microdiscectomy were compared. In 216 patients, CPK was measured before surgery and at day 1 after surgery. In 140 patients, the CSA of the multifidus muscle was measured at the affected disc level before surgery and at 1 year after surgery. The ratios (i.e. post surgery/pre surgery) of CPK and CSA were used as outcome measures. The multifidus atrophy was classified into three grades ranging from 0 (normal) to 3 (severe atrophy), and the difference between post and pre surgery was used as an outcome. Patients’ low-back pain scores on the visual analogue scale (VAS) were documented before surgery and at various moments during follow-up.

Tubular discectomy compared with conventional microdiscectomy resulted in a nonsignificant difference in CPK ratio, although the CSA ratio was significantly lower in tubular discectomy. At 1 year, there was no difference in atrophy grade between both groups nor in the percentage of patients showing an increased atrophy grade (14% tubular vs. 18% conventional). The postoperative low-back pain scores on the VAS improved in both groups, although the 1-year between-group mean difference of improvement was 3.5 mm (95% CI; 1.4–5.7 mm) in favour of conventional microdiscectomy.

In conclusion, tubular discectomy compared with conventional microdiscectomy did not result in reduced muscle injury. Postoperative evaluation of CPK and the multifidus muscle showed similar results in both groups, although patients who underwent tubular discectomy reported more lowback pain during the first year after surgery.

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Arachnoid cysts of the middle cranial fossa accompanied by subdural effusions—experience with 60 consecutive cases

Acta Neurochir (2011) 153:75–84 DOI 10.1007/s00701-010-0820-5

Subdural effusions (SDEs) can complicate arachnoid cysts of the middle cranial fossa (ACMFs). While there is a consensus that at least in adults asymptomatic ACMFs should not be operated, those with concomitant subdural and/or intracystic effusions are clinically apparent in the majority of cases and should be surgically treated. But it remains unclear, which surgical procedure is best.

Methods Since 1980, 60 out of 343 patients with an ACMF presented with accompanying SDEs. Four categories of SDEs were differentiated radiologically. This collective was controlled in a follow-up study up to 60 months after con- servative or operative treatment by clinical and radiological means.

Results In 54 of the 60 patients, we saw an indication for surgical treatment. Twenty-nine patients received a burr hole, 13 cases were treated by craniotomy, seven by endoscopical means, three patients underwent shunting and two combined procedures. Six patients were treated conservatively. An excellent final clinical outcome was observed in 55 cases. While craniotomy succeeded best to reduce the cyst volume in postoperative CT, the final clinical outcome did not differ significantly compared with burr hole trepanation.

Conclusions Patients with small effusions can be treated conservatively in selected cases. Based on our experience, we prefer a differentiated therapy. As first procedure, burr hole and subdural drainage were performed, leaving the cyst alone, seeming sufficient for the majority of cases. Craniotomy or endoscopical means should be reserved as treatment of choice for special cases, depending on category and acuteness of SDE and size/localisation of the ACMF.

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A Prospective, Nonrandomized, Multicenter Evaluation of Extreme Lateral Interbody Fusion for the Treatment of Adult Degenerative Scoliosis

Spine 2010;35: S322–S330

Study Design. Prospective multicenter nonrandomized institutional review board-approved observational study of clinical and radiographic outcomes of the extreme lateral interbody fusion (XLIF) procedure in adult scoliosis.

Objective. Perioperative measures from this longitudinal study were compiled to identify the short-term results and complications of the procedure.

Summary of Background Data. The surgical treatment of adult scoliosis presents a treatment challenge. Neural decompression with combined anterior/posterior instrumented fusion is often performed. These procedures have been reported to carry a high risk of complication, particularly in the elderly patient population. Over the past decade, less invasive surgical approaches to neural decompression and fusion have been popularized and have recently been applied in the treatment of degenerative scoliosis. To date, there has been little published data evaluating these treatment approaches.

Methods. A total of 107 patients who underwent the XLIF procedure with or without supplemental posterior fusion for the treatment of degenerative scoliosis were prospectively studied. Intraoperative data collection included surgical procedural details, operative time, estimated blood loss, and surgical complications. Postoperative complications, length of hospital stay, and neurologic status were recorded. For this report, perioperative data (inclusive of outcomes through the 6-week postoperative clinic visit) were evaluated.

Results. In all, 107 patients (mean age, 68 years; range, 45–87) were treated with XLIF; 28% had at least 1 comorbidity. A mean of 4.4 levels (range, 1–9) were treated per patient. Supplemental pedicle screw fixation was used in 75.7% of patients, 5.6% had lateral fixation, and 18.7% had stand-alone XLIF. Mean operative time and blood loss were 178 minutes (58 minutes/level) and 50 to 100 mL. Mean hospital stay was 2.9 days (unstaged), 8.1 day (staged, 16.5%), 3.8 days overall. Five patients (4.7%) received a transfusion, 3 (2.8%) required intensive care unit admission, and 1 (0.9%) required rehabilitation services. Major complications occurred in 13 patients (12.1%): 2 (1.9%) medical, 12 (11.2%) surgical. Of procedures that involved only less invasive techniques (XLIF stand-alone or with percutaneous instrumentation), 9.0% had one or more major complications. In those with supplemental open posterior instrumentation, 20.7% had one or more major complication. Early reoperations (3) (all for deep wound infections) were associated with open posterior instrumentation procedures.

Conclusion. The morbidity in adult scoliosis surgery is minimized with less invasive techniques. The rate of major complications in this study (12.1%) compares favorably to that reported from other studies of surgery for degenerative deformity.

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Postshunt Cognitive and Functional Improvement in Idiopathic Normal Pressure Hydrocephalus

Neurosurgery 68:416–419, 2011 DOI: 10.1227/NEU.0b013e3181ff9d01

Improvement in gait after shunt placement has been well documented in idiopathic normal pressure hydrocephalus (iNPH); however, controversy remains regarding the extent and pattern of postsurgical cognitive changes. Conflicting findings may be explained by variability in both test selection and follow-up intervals across studies. Furthermore, most investigations lack a control group, making it difficult to disentangle practice effects from a true treatment effect.

OBJECTIVE: To examine postshunt changes in a sample of well-characterized iNPH participants compared with a group of age- and education-matched healthy control subjects.

METHODS: We identified 12 participants with iNPH undergoing shunt placement and 9 control participants. All participants were evaluated with comprehensive neuropsychological testing and standardized gait assessment at baseline and were followed up for 6 months.

RESULTS: Repeated-measures analysis of variance revealed a significant group- (iNPH and control) by-time (baseline and 6 months) interaction for Trailmaking Test B: (P< .003) and Symbol Digit Modalities (P< .02), with greater improvement in iNPH participants relative to control subjects. In addition, the iNPH group showed greater improvement in gait (P< .001) and caregivers reported improved activities of daily living (P , .01) and reduced caregiver distress (P< .01).

CONCLUSION: This study demonstrates improvements in mental tracking speed and sustained attention 6 months after shunt placement in iNPH. The present investigation is the first study to use a controlled design to show that cognitive improvement in iNPH is independent of practice effects. Furthermore, these findings indicate functional and quality-of-life improvements for both the shunt responder and their caregiver.

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Chronic subdural hematoma in the elderly: not a benign disease

J Neurosurg 114:72–76, 2011. (DOI: 10.3171/2010.8.JNS10298)

Chronic subdural hematoma (CSDH) is perceived to be a “benign,” easily treated condition in the elderly, but reported follow-up periods are brief, usually limited to acute hospitalization.

Methods. The authors conducted a retrospective review of data obtained in a prospectively identified consecutive series of adult patients admitted to their institution between September 2000 and February 2008 and in whom there was a CT diagnosis of CSDH. Survival data were compared to life-table data.

Results. Of the 209 cases analyzed, 63% were men and the mean age was 80.6 years (range 65–96 years). Primary surgical interventions performed were bur holes in 21 patients, twist-drill closed-system drainage in 44, and craniotomies in 72. An additional 72 patients were simply observed. Reoperations were recorded in 5 patients—4 who had previously undergone twist-drill drainage and 1 who had previously undergone a bur hole procedure (p = 0.41, chi-square analysis). Thirty-five patients (16.7%) died in hospital, 130 were discharged to rehabilitation or a skilled care facility, and 44 returned home. The follow-up period extended to a maximum of 8.3 years (median 1.45 years). Six-month and 1-year mortality rates were 26.3% and 32%, respectively. In the multivariate analysis (step-wise logistic regression), the sole factor that predicted in-hospital death was neurological status on admission (OR 2.1, p = 0.02, for each step). Following discharge, the median survival in the remaining cohort was 4.4 years. In the Cox proportional hazards model, only age (hazard ratio [HR] 1.06/year, p = 0.02) and discharge to home (HR 0.24, p = 0.01) were related to survival, whereas the type of intervention, whether surgery was performed, size of subdural hematoma, amount of shift, bilateral subdural hematomas, and anticoagulant agent use did not affect the long- or short-term mortality rate. Comparison of postdischarge survival and anticipated actuarial survival demonstrated a markedly increased mortality rate in the CSDH group (median survival 4.4 vs 6 years, respectively; HR 1.94, p = 0.0002, log-rank test). This excess mortality rate was also observed at 6 months postdischarge with evidence of normalization only at 1 year.

Conclusions. In this first report of the long-term outcome of elderly patients with CSDH the authors observed persistent excess mortality up to 1 year beyond diagnosis. This belies the notion that CSDH is a benign disease and indicates it is a marker of other underlying chronic diseases similar to hip fracture

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Incidence of Unintended Durotomy in Spine Surgery Based on 108.478 Cases

Neurosurgery 68:117–124, 2011 DOI: 10.1227/NEU.0b013e3181fcf14e

Unintended durotomy is a common complication of spinal surgery. However, the incidences reported in the literature vary widely and are based primarily on relatively small case numbers from a single surgeon or institution.

OBJECTIVE: To provide spine surgeons with a reliable incidence of unintended durotomy in spinal surgery and to assess various factors that may influence the risk of durotomy.

METHODS: We assessed 108.478 surgical cases prospectively submitted by members of the Scoliosis Research Society to a deidentified database from 2004 to 2007.

RESULTS: Unintended durotomy occurred in 1.6% (1745 of 108.478) of all cases. The incidence of unintended durotomy ranged from 1.1% to 1.9% on the basis of preoperative diagnosis, with the highest incidence among patients treated for kyphosis (1.9%) or spondylolisthesis (1.9%) and the lowest incidence among patients treated for scoliosis (1.1%). The most common indication for spine surgery was degenerative spinal disorder, and among these patients, there was a lower incidence of durotomy for cervical (1.0%) vs thoracic (2.2%; P = .01) or lumbar (2.1%, P < .001) cases. Scoliosis procedures were further characterized by etiology, with the highest incidence of durotomy in the degenerative subgroup (2.2% vs 1.1%; P < .001). Durotomy was more common in revision compared with primary surgery (2.2% vs 1.5%; P < .001) and was significantly more common among elderly (. 80 years of age) patients (2.2% vs 1.6%; P = .006). There was a significant association between unintended durotomy and development of a new neurological deficit (P < .001).

CONCLUSION: Unintended durotomy occurred in at least 1.6% of spinal surgeries, even among experienced surgeons. Our data provide general benchmarks of durotomy rates and serve as a basis for ongoing efforts to improve safety of care.

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Ruptured anterior paraclinoid aneurysms

Neurosurg Rev (2011) 34:49–55. DOI 10.1007/s10143-010-0272-7

The purpose of this study was to evaluate cases of subarachnoid hemorrhage (SAH) from ruptured anterior (dorsal) paraclinoid aneurysms.

Anterior paraclinoid aneurysms are defined as aneurysms arising from the anterolateral wall of the proximal internal carotid artery without any relationship to an arterial branch.

Methods. Between 1991 and 2008, a total of 159 patients with 169 paraclinoid aneurysms were treated at the Shinshu University Hospital and its affiliated hospitals. A retrospective analysis was carried out using charts, operation records, operation videos, and neuroimagings.

Results. Twenty six patients had anterior paraclinoid aneurysm. Six patients presented with SAH. Three aneurysms were saccular and the others were blister-like aneurysms based on operative findings. Neck laceration or premature rupture frequently happened during the clipping surgery even though the aneurysm was saccular type.

Conclusions. The treatment of a ruptured anterior paraclinoid aneurysm is quite difficult. Trapping and bypass would be recommended for such fragile aneurysms.

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Results Following Gamma Knife Radiosurgical Anterior Capsulotomies for Obsessive Compulsive Disorder

Neurosurgery 68:28–33, 2011 DOI: 10.1227/NEU.0b013e3181fc5c8b

Obsessive compulsive disorder (OCD), in its severe form, can cause tremendous disability for affected patients.

OBJECTIVE: To evaluate the results following bilateral radiosurgical anterior capsulotomy for severe medically refractory OCD.

METHODS: We performed gamma knife anterior capsulotomy (GKAC) on 3 patients with extreme, medically intractable OCD. According to our protocol, all patients were evaluated by at least 2 psychiatrists who recommended surgery. The patient had to request the procedure, and had to have severe OCD according to the Yale-Brown Obsessive Compulsive Scale (YBOCS). Patient ages were 37, 55, and 40 years, and pre-radiosurgery YBOCS scores were 34/40, 39/40, and 39/40. Bilateral lesions were created with 2 4-mm isocenters to create an oval volume in the ventral internal capsule at the putaminal midpoint. A maximum dose of 140 or 150 Gy was used.

RESULTS: There was no morbidity after the procedure, and all patients returned immediately to baseline function. All patients noted significant functional improvements, and reduction in OCD behavior. Follow-up was at 55, 42, and 28 months. The first patient reduced her YBOCS score from 34 to 24. One patient with compulsive skin picking and an open wound had later healing of the chronic wound and a reduction in the YBOCS score from 39 to 8. At 28 months, the third patient is living and working independently, and her YBOCS score is 18.

CONCLUSION: Within a strict protocol, gamma knife radiosurgery provided improvement of OCD behavior with no adverse effects. This technique should be evaluated further in patients with severe and disabling behavioral disorders.

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Extended endoscopic transphenoidal approach for tuberculum sellae meningiomas

Acta Neurochir (2011) 153:1–9. DOI 10.1007/s00701-010-0788-1

Removal of tuberculum sella (TS) meningiomas is traditionally performed through transcranial approaches. Wide use of the endoscope in transphenoidal pituitary surgery is recently accessible through the tuberculum sellae with an endoscope-assisted or purely endoscopic technique. Extended endoscopic approach is an important and alternative route for meningiomas, which are located on the midline originating from the tuberculum sella. However, cerebrospinal fluid (CSF) leakage is an important problem in extended endoscopic approaches. In this report, we discuss surgical limitations and nuances of endoscopic transphenoidal approach from a retrospective analysis of nine patients with TS meningiomas.

Methods: Endoscopic transphenoidal approach was performed for seven women and two men (mean age, 51.1 years; age range, 32–78 years) with TS meningiomas between July 2007 and March 2010 in the Department of Neurosurgery, Kocaeli, Turkey.

Results: Total removal was achieved in six of nine patients. An improvement of the preoperative visual deficits was observed in six of the nine patients. Multilayer closure was performed for reconstruction, and lumbar external drainage was used for all patients for 3–5 days. CSF leakage was not seen in any of the patients after the operation and removal of the drainage.

Conclusion: Endoscopic extended transphenoidal approach is still not a standardized procedure for TS meningiomas, but it may be considered as an alternative procedure in selected cases.

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Facet Joint Biomechanics at the Treated and Adjacent Levels After Total Disc Replacement

SPINE Volume 36, Number 1, pp E27–E32

Study Design. Biomechanical study using human cadaveric lumbar spines.

Objective. To evaluate effects of total disc replacement (TDR) on spine biomechanics at the treated and adjacent levels.

Summary of Background Data. Previous studies on spine biomechanics after TDR were focused on facet forces and range of motion and report contradictory results. Characterization of contact pressure, peak contact pressure, force, and peak force before and after TDR may lead to a better understanding of facet joint function and may aid in prediction of long-term outcomes after TDR.

Methods. Seven fresh-frozen human cadaveric lumbar spines were potted at T12 and L5 and installed in a 6 degrees of freedom displacement- controlled testing system. Displacements of 15° flexion/ extension, 10° right/left bending, and 10° right/left axial rotation were applied. Contact pressure, peak contact pressure, force, peak force, and contact area for each facet joint were recorded at L2–L3 and L3–L4 both before and after TDR at L3–L4. The data were analyzed with analysis of variance and t tests.

Results. Axial rotation had the most impact on contact pressure, peak contact pressure, force, peak force, and contact area in intact spines. During lateral bending and axial rotation, TDR resulted in a significant increase in facet forces at the level of treatment and a decrease in contact pressure, peak contact pressure, and peak force at the level superior to the TDR. With flexion/extension, there was a decrease in peak contact pressure and peak contact force at the superior level.

Conclusion. Our study demonstrates that rotation is the most demanding motion for the spine. We also found an increase in facet forces at the treated level after TDR. We are the first to show a decrease in several biomechanical parameters after TDR at the adjacent superior level. In general, our findings suggest there is an increase in loading of the facet joints at the level of disc implantation and an overall unloading effect at the level above.

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Microsurgery for Previously Coiled Aneurysms: Experience With 81 Patients

Neurosurgery 68:140–154, 2011 DOI: 10.1227/NEU.0b013e3181fd860e

Residual and recurrent intracranial aneurysms after endovascular treatment with Guglielmi detachable coils may necessitate a microsurgical occlusion.

OBJECTIVE: To analyze the microsurgical technique and describe how the location, morphology, and appearance of the coiled aneurysm affect the technique.

METHODS: We retrospectively analyzed 81 patients with 82 previously coiled aneurysms treated microsurgically at 2 Finnish neurosurgical university hospitals in Helsinki and Kuopio between July 1995 and August 2009. Seven videos were selected to demonstrate the microsurgical strategy in various locations.

RESULTS: Fifty-eight aneurysms (71%) were located at anterior circulation and 24 (29%) at posterior circulation. Fifteen patients were operated on within the first month (early surgery) after coiling, whereas 66 were treated later (late surgery). Complete or partial removal of coils during surgery may facilitate clipping, but is significantly (P, .001) more difficult to accomplish in late surgery. Removal of coils may also increase the chance of poor outcome. Chance of poor outcome also increased with intraoperative aneurysm rupture, size of the aneurysm, and posterior circulation location. Good clinical outcome (same or better clinical condition 3 months after surgery) was achieved in 71 patients (88%). After microsurgery, 4 patients were severely disabled and 6 patients died, 3 of them because of poor clinical condition.

CONCLUSION: Complete microsurgical occlusion of the residual aneurysm is possible. However, in large or giant aneurysms direct microsurgery is a challenging high-risk procedure, and we recommend that these patients be referred to a dedicated neurovascular center to minimize surgical complications. Even in experienced hands, use of different bypass procedures may be the best option for demanding growing lesions, especially those in the posterior circulation.

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Accuracy of Free-Hand Pedicle Screws in the Thoracic and Lumbar Spine: Analysis of 6816 Consecutive Screws

Neurosurgery 68:170–178, 2011 DOI: 10.1227/NEU.0b013e3181fdfaf4

Pedicle screws are used to stabilize all 3 columns of the spine, but can be technically demanding to place. Although intraoperative fluoroscopy and stereotactic- guided techniques slightly increase placement accuracy, they are also associated with increased radiation exposure to patient and surgeon as well as increased operative time.

OBJECTIVE: To describe and critically evaluate our 7-year institutional experience with placement of pedicle screws in the thoracic and lumbar spine using a free-hand technique.

METHODS: We retrospectively reviewed records of all patients undergoing free-hand pedicle screw placement without fluoroscopy in the thoracic or lumbar spine between June 2002 and June 2009. Incidence and extent of cortical breach by misplaced pedicle screw was determined by review of postoperative computed tomography scans. We defined breach as more than 25% of the screw diameter residing outside of the pedicle or vertebral body cortex.

RESULTS: A total of 964 patients received 6816 free-hand placed pedicle screws in the thoracic or lumbar spine. Indications for hardware placement were degenerative/deformity disease (51.2%), spondylolisthesis (23.7%), tumor (22.7%), trauma (11.3%), infection (7.6%), and congenital (0.9%). A total of 115 screws (1.7%) were identified as breaching the pedicle in 87 patients (9.0%). Breach occurred more frequently in the thoracic than the lumbar spine (2.5% and 0.9%, respectively; P , .0001) and was more often lateral (61.3%) than medial (32.8%) or superior (2.5%). T4 (4.1%) and T6 (4.0%) experienced the highest breach rate, whereas L5 and S1 had the lowest breach rate. Eight patients (0.8%) underwent revision surgery to correct malpositioned screws.

CONCLUSION: Free-hand pedicle screw placement based on external anatomy alone can be performed with acceptable safety and accuracy and allows avoidance of radiation exposure encountered in fluoroscopic techniques. Image-guided assistance may be most valuable when placing screws between T4 and T6, where breach rates are highest

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Long-term Results of the Neuroendoscopic Management of Colloid Cysts of the Third Ventricle: A Series of 90 Cases

Neurosurgery 68:179–187, 2011 DOI: 10.1227/NEU.0b013e3181ffae71

The endoscopic removal of third ventricular colloid cysts has been developed as an alternative to microsurgical transcortical-transventricular and transcallosal approaches.

OBJECTIVE: To examine the value of endoscopic technique by reviewing the large number of endoscopically treated patients with long-term follow-up in 2 neurosurgical centers.

METHODS: A retrospective chart review was conducted for all patients admitted for resection of a third ventricular colloid cyst to the Radboud University Nijmegen Medical Centre (Nijmegen, the Netherlands) and the Hoˆ pital Henri Mondor (Paris, France) between 1994 and 2007. Both clinical and radiological symptoms and operative results were evaluated.

RESULTS: Postdischarge clinical follow-up was available for 85 patients over a mean period of 4 years 3 months. Permanent morbidity occurred in 1 patient (persisting preoperative memory deficit). Follow-up imaging of 80 evaluable patients showed that total or nearly total cyst removal was possible in 46 individuals (57.5%). Residual cyst was present in 34 patients (42.5%), and 6 required repeated endoscopic surgery for symptomatic regrowth. Recurrent cysts were mainly seen within the first 2 years after surgery.

CONCLUSION: It is debatable whether the higher numbers of recurrent or residual cysts can be justified by the slightly lower complication rates achieved with endoscopic removal. However, results have been improving over the years. Moreover, the modifications observed on control magnetic resonance images justify the need for regular control imaging for at least the first 2 years postoperatively.

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The Association Between Weather and Spontaneous Subarachnoid Hemorrhage: An Analysis of 155 US Hospitals

Neurosurgery 68:132–139, 2011 DOI: 10.1227/NEU.0b013e3181fe23a1

A seasonal and meteorological influence on the incidence of spontaneous subarachnoid hemorrhage (SAH) has been suggested, but a consensus in the literature has yet to emerge.

OBJECTIVE: This study examines the impact of weather patterns on the incidence of SAH using a geographically broad analysis of hospital admissions and represents the largest study of the topic to date.

METHODS: We retrospectively analyzed SAH admissions to 155 US hospitals during the calendar years 2004 to 2008 (N = 7758). Daily weather readings for temperature, pressure, and humidity were obtained for the same period from National Oceanic and Atmospheric Administration weather stations located near each hospital. The daily values of each weather variable were associated with the daily volume of SAH admissions using a combination of correlation and time-series analyses.

RESULTS: No seasonal trends were observed in the monthly volume of SAH admissions during the study period. No significant correlation was detected between the daily SAH admission volume and the day’s weather, the previous day’s weather, or the 24-hour weather change.

CONCLUSION: This study represents the most comprehensive investigation of the association between weather and spontaneous SAH to date. The results suggest that neither season nor weather significantly influences the incidence of SAH.

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