The Palatal Approach for Direct Maxillary Sinus Floor Elevation: A Case Report.

INTRODUCTION: The traditional techniques of maxillary sinus floor elevation via a direct or indirect approach are suitable for the majority of cases. However, in cases of unfavorable anatomy and/or a thick lateral bony wall, we propose here a new approach for sinus floor elevation. CASE PRESENTATION: Forty-two-year-old female presents for sinus floor elevation after a failed attempt due to anatomical limitations and intraoperative complications. During the second surgical procedure, the access to the sinus membrane was performed from the palatal side due to thickness of the buccal wall ranging from 6 to 9 mm and the presence of septa. The sinus augmentation was successful, allowing for future implant placement. CONCLUSION: In selected cases, when the anatomy of the maxillary sinus poses limitations and the lateral wall thickness requires significant bone removal, the palatal approach is a valid alternative to the traditional sinus augmentation techniques.

Advancement of Surgical Visualization Methods: Comparison Study Between Traditional Microscopic Surgery and a Novel Robotic Optoelectronic Visualization Tool for Spinal Surgery.

INTRODUCTION: The operating microscope (OM) has become instrumental in aiding surgeons during key microdissection with greater safety and detail. An exoscope offers similar detail with improved functionality and greater implications for live teaching and improved operating room flow. METHODS: Eleven senior neurosurgery residents and fellows performed unilateral, single-level laminotomies on fresh cadavers using an OM and exoscope. Three attending spine surgeons blinded for the visualization technique used then reviewed and graded each decompression. Data points gathered included time of procedure, grading of decompression (1-5), and complications, including dural tear, nerve root injury, and pars fracture. RESULTS: Operative times between the 2 systems were not significantly different (14.9 minutes OM vs. 15.6 minutes exoscope, P = 0.766). Despite high variability between evaluators in assessing complications and adequacy of decompression, there was no significant difference between either system. Postprocedural surveys indicated greater comfort with the exoscope, greater ease of use, and superior teaching potential for the exoscope over the standard OM. CONCLUSION: In our simulated operating room model, an exoscope is a valid alternative to the standard OM that affords the surgeon greater comfort with greater teaching potential while maintaining many of the microscope's benefits.

Lateral Thoracic Osteoplastic Rib-Sparing Technique Used for Lateral Spine Surgery: Technical Note.

Of patients who have undergone lateral approaches to the thoracic spine, surgical site postoperative pain appears to be greater among those who have undergone transection and removal of a rib segment than those who have not. Therefore, techniques that conserve anatomical position and minimize tissue disruption would theoretically result in less pain and a quicker recovery. Herein, we describe a rib-sparing osteoplastic technique used when rib segments need to be displaced in order to create an unobscured corridor to the operative target. Our approach minimizes soft tissue disruption and restores the anatomical function of the rib. Based on our experience, these patients report less pain, mobilize earlier, and are discharged sooner than those who have had rib segments sacrificed as part of a lateral approach to the spine.

Venous air embolus during prone cervical spine fusion: case report.

Venous air embolism (VAE) is a known neurosurgical complication classically and most frequently occurring in patients undergoing posterior cranial fossa or cervical spine surgery in a sitting or semi-sitting position. The authors present a case of VAE that occurred during posterior cervical spine surgery in a patient in the prone position, a rare intraoperative complication. The patient was a 65-year-old man who was undergoing a C1-2 fusion for a nonunion of a Type II dens fracture and developed a VAE. While VAE in the prone position is uncommon, it is a neurosurgical complication that may have significant clinical implications both intraoperatively and postoperatively. The aim of this review is 2-fold: 1) to improve the general knowledge of this complication among surgeons and anesthesiologists who may not otherwise suspect air embolism in patients positioned prone for posterior cervical spine operations, and 2) to formulate preventive measures as well as a plan for prompt diagnosis and treatment should this complication occur.

The Vertebral Artery Cave at C2: Anatomic Study with Application to C2 Pedicle Screw Placement.

OBJECTIVE: Knowledge of the course of the vertebral artery during instrumentation is of paramount importance. It has been shown that erosion of the C2 pedicle and body can occur due to pulsations of the adjacent vertebral artery. This often results in a "cave" for this segment of the artery. The descriptions of this anatomy are limited. The current study was performed with the hope that these data will be of use to spine surgeons during C2 instrumentation. METHODS: In 40 human adult C2 bone specimens, the position of the vertebral artery in relation to the undersurface of the superior articular facet, pedicle, and C2 body was observed. A classification system was used to better describe these relationships. Pedicle screws were then placed into selected examples of each type. RESULTS: We found type 0 specimens, with no cave, on 8 sides (10%). Types I, II, and III caves with minimal, moderate, and significant encroachment of the pedicle were observed on 40%, 35%, and 27.5% sides, respectively. Type IV caves with erosion into the lateral C2 body and undersurface of the superior articular facet were observed on 12.5% of sides. Although larger caves were found on left sides, this did not reach statistical significance. Pedicle screw placement for types III and IV were most likely to enter the vertebral artery cave (P < 0.05). CONCLUSIONS: Additional osteologic data regarding the course of the vertebral artery while within C2 may decrease morbidity during surgery in this region.

Arterial variations around the atlas: a comprehensive review for avoiding neurosurgical complications.

INTRODUCTION: Neurosurgical approaches often involve the atlas. Therefore, the arterial relationships and anatomical variations are of paramount importance to the neurosurgeon. METHODS: Using standard search engines, a literature review of arterial variants near the first cervical vertebra was performed. CONCLUSIONS: Arterial variations around the atlas are surgically significant. Awareness of their existence and course may provide better pre-operative planning and surgical intervention, potentially leading to better clinical outcomes. Three-dimensional computed tomography angiography (3D CTA) is an important tool for identifying and diagnosing such abnormalities and should be used when such vascular anomalies are suspected.

Comparing Radiation Dose from Conventional Fluoroscopy to Intraoperative Cone Beam CT (O-arm) during Percutaneous Lesioning Procedures of the Gasserian Ganglion.

INTRODUCTION: The use of intraoperative CT-guidance during the percutaneous treatment of trigeminal neuralgia has become increasingly popular due to the greater ease of foramen ovale cannulation and decreased procedure times. Concerns regarding radiation dose to the patient, however, remain unaddressed. We sought to compare the emitted radiation dose from fluoroscopy with intraoperative CT for these procedures. METHODS: A retrospective review of percutaneous lesioning procedures for trigeminal neuralgia performed between 2010 until 2012 at our institution was conducted and radiation doses to the patient were recorded. We subsequently simulated four separate percutaneous trigeminal rhizotomies using the O-arm intraoperative CT (Medtronics, Minneapolis, MN, USA) to cannulate the foramen ovale bilaterally in two formalin-fixed cadaver heads. RESULTS: Seventeen successful percutaneous treatments for trigeminal neuralgia were performed during the study period. Eleven procedures containing complete records were included in the final analysis. For procedures using fluoroscopy, the mean dosage was 15.2 mGys (range: 1.15 - 47.95, 95% CI 7.34 - 22.99). Radiation dosage from the O-arm imaging system was 16.55 mGy for all four cases. An unequal variance t-test did not reach statistical significance (p=0.42). CONCLUSIONS: We did not observe a significant difference in radiation dose delivered to subjects when comparing CT-guided foramen ovale cannulation relative to fluoroscopy for percutaneous lesioning of the Gasserian ganglion. Additional study is required under operational settings.

Technical Note - Lateral Approach to the Lumbar Spine for the Removal of Interbody Cages.

Revision surgery to address the migration or fracture of a lumbar interbody cage can be technically challenging. Scar tissue and fibrosis, among other anatomic barriers, can make removal of the cage a complicated procedure, potentially increasing postoperative pain as well as the probability of neurologic deficits. Use of the lateral surgical technique for removal of the cage can avoid these potential complications. In this case report, we describe the removal of interbody cages through a lateral approach in three patients without the necessity of additional posterior hardware revision.

Neurosurgery simulation in residency training: feasibility, cost, and educational benefit.

BACKGROUND: The effort required to introduce simulation in neurosurgery academic programs and the benefits perceived by residents have not been systematically assessed. OBJECTIVE: To create a neurosurgery simulation curriculum encompassing basic and advanced skills, cadaveric dissection, cranial and spine surgery simulation, and endovascular and computerized haptic training. METHODS: A curriculum with 68 core exercises per academic year was distributed in individualized sets of 30 simulations to 6 neurosurgery residents. The total number of procedures completed during the academic year was set to 180. The curriculum includes 79 simulations with physical models, 57 cadaver dissections, and 44 haptic/computerized sessions. Likert-type evaluations regarding self-perceived performance were completed after each exercise. Subject identification was blinded to junior (postgraduate years 1-3) or senior resident (postgraduate years 4-6). Wilcoxon rank testing was used to detect differences within and between groups. RESULTS: One hundred eighty procedures and surveys were analyzed. Junior residents reported proficiency improvements in 82% of simulations performed (P < .001). Senior residents reported improvement in 42.5% of simulations (P < .001). Cadaver simulations accrued the highest reported benefit (71.5%; P < .001), followed by physical simulators (63.8%; P < .001) and haptic/computerized (59.1; P < .001). Initial cost is $341,978.00, with $27,876.36 for annual operational expenses. CONCLUSION: The systematic implementation of a simulation curriculum in a neurosurgery training program is feasible, is favorably regarded, and has a positive impact on trainees of all levels, particularly in junior years. All simulation forms, cadaver, physical, and haptic/computerized, have a role in different stages of learning and should be considered in the development of an educational simulation program.

The role of flexible hollow core carbon dioxide lasers in resection of lumbar intraspinal lipomas.

PURPOSE: The authors assess the role of flexible hollow core CO2 laser system (Omniguide system) in resection of intraspinal lipomas. METHODS: Eight patients with intraspinal lipomas were operated using an Omniguide laser system over a 22-month period. The age range varied between 6 months and 16 years. All of them had lipoma of the conus medullaris associated with lumbar subcutaneous lipoma. Two of these had previous surgery with resection of the subcutaneous part of the lipoma; in one of them, a partial resection of the conus medullaris lipoma had also been performed. In six, there were no obvious motor or sensory deficits whereas two had gross neurologic deficits, with the deficits occurring in one after the previous decompression. Resection of the conus lipoma, untethering of the spinal cord, and reconstruction of the decompressed conus was performed in all aided with Omniguide laser system. The power settings of the laser system ranged from 4 to 8 W. RESULTS: Subtotal to near-total resection was achieved in all. None of the patients developed any new motor or sensory deficits. Three had postoperative CSF leaks which initially required reoperation with graft resuturing and subsequently placement of lumboperitoneal shunt. One child with preexisting neurologic deficits improved in power over the next 12 months. CONCLUSION: Flexible CO2 laser system was precise and convenient in decompressing the conus lipomas and untethering of the cord in lumbar spinal lipomas.

Aqueductal developmental venous anomaly as an unusual cause of congenital hydrocephalus: a case report and review of the literature.

INTRODUCTION: Aqueductal stenosis may be caused by a number of etiologies including congenital stenosis, tumor, inflammation, and, very rarely, vascular malformation. However, aqueductal stenosis caused by a developmental venous anomaly presenting as congenital hydrocephalus is even more rare, and, to the best of our knowledge, has not yet been reported in the literature. In this study, we review the literature and report the first case of congenital hydrocephalus associated with aqueductal stenosis from a developmental venous anomaly. CASE PRESENTATION: The patient is a three-day-old, African-American baby girl with a prenatal diagnosis of hydrocephalus. She presented with a full fontanelle, splayed sutures, and macrocephaly. Postnatal magnetic resonance imaging showed triventricular hydrocephalus, suggesting aqueductal stenosis. Examination of the T1-weighted sagittal magnetic resonance imaging enhanced with gadolinium revealed a developmental venous anomaly passing through the orifice of the aqueduct. We treated the patient with a ventriculoperitoneal shunt. CONCLUSIONS: Ten cases of aqueductal stenosis due to venous lesions have been reported and, although these venous angiomas and developmental venous anomalies are usually considered congenital lesions, all 10 cases became symptomatic as older children and adults. Our case is the first in which aqueductal stenosis caused by a developmental venous anomaly presents as congenital hydrocephalus. We hope adding to the literature will improve understanding of this very uncommon cause of hydrocephalus and, therefore, will aid in treatment.

Molecular disruption of RAD50 sensitizes human tumor cells to cisplatin-based chemotherapy.

Platinum-based drugs that induce DNA damage are commonly used first-line chemotherapy agents for testicular, bladder, head and neck, lung, esophageal, stomach, and ovarian cancers. The inherent resistance of tumors to DNA damage often limits the therapeutic efficacy of these agents, such as cisplatin. An enhanced DNA repair and telomere maintenance response by the Mre11/Rad50/Nbs1 (MRN) complex is critical in driving this chemoresistance. We hypothesized therefore that the targeted impairment of native cellular MRN function could sensitize tumor cells to cisplatin. To test this, we designed what we believe to be a novel dominant-negative adenoviral vector containing a mutant RAD50 gene that significantly downregulated MRN expression and markedly disrupted MRN function in human squamous cell carcinoma cells. A combination of cisplatin and mutant RAD50 therapy produced significant tumor cytotoxicity in vitro, with a corresponding increase in DNA damage and telomere shortening. In cisplatin-resistant human squamous cell cancer xenografts in nude mice, this combination therapy caused dramatic tumor regression with increased apoptosis. Our findings suggest the use of targeted RAD50 disruption as what we believe to be a novel chemosensitizing approach for cancer therapy in the context of chemoresistance. This strategy is potentially applicable to several types of malignant tumors that demonstrate chemoresistance and may positively impact the treatment of these patients.

Chitosan glycerophosphate-based semirigid dexamethasone eluting biodegradable stent.

BACKGROUND: Chitosan is a polysaccharide derived from chitin deacetylation, which can form a biodegradable matrix capable of reversibly binding dexamethasone. The purpose of this study was to optimize the chitosan formulation to produce a pliable sheet, to assess the innate longevity and inflammatory potential of the polymer, and to study the in vivo rate of dexamethasone release over time. METHODS: Chitosan glycerophosphate (CGP) sheets were produced with varying degrees of deacetylation (70-100%) and analyzed for structural integrity. Two-squared centimeter sheets of 91.7% deacetylated CGP were mixed with dexamethasone and implanted in 12 rabbit maxillary sinuses. Nasal lavage and peripheral blood samples were tested for dexamethasone levels by enzyme-linked immunosorbent assay (ELISA) over 15 days. Sinuses were examined histologically on postoperative days 3, 7, and 15 for persistence of the stent and degree of inflammation when compared with CGP alone. RESULTS: The 91.7% deacetylated CGP formulation was found to have optimal mechanical properties and remained present with moderate degradation and negligible inflammation through postoperative day 15. Dexamethasone levels were detectable in nasal lavage and blood samples through postoperative day 15 and decayed over time (lavage: day 0, 7.70 +/- 0.97 ng/mL, and day 15, 2.53 +/- 1.71 ng/mL; blood: day 3, 2.51 +/- 0.14 ng/mL, and day 15, 1.70 +/- 0.36 ng/mL). CONCLUSION: CGP may be used to create a semirigid sheet that is malleable, inert, and capable of eluting steroid over 15 days when implanted intranasally. This material may be used to create a pharmacologically active stent that spontaneously degrades over time.

A novel controlled local drug delivery system for inner ear disease.

PURPOSE: Our goal is to develop a novel drug delivery system that can potentially improve clinical outcomes compared to current methods of dosing drugs such as dexamethasone or gentamicin. This system focuses on a single local application to the inner ear via the round window membrane. HYPOTHESIS: A chitosan-glycerophosphate (CGP)-hydrogel based drug delivery system can be engineered to provide local and sustained drug release to the inner ear. STUDY DESIGN: In vitro: drug release and (CGP)-hydrogel matrix degradation were characterized using dexamethasone as a model drug. In vivo: dexamethasone laden CGP-hydrogel was placed in the round window niche of mice. Perilymph samples were obtained from the oval window and analyzed for dexamethasone. The impact of CGP-hydrogel on auditory function was evaluated. RESULTS: In vitro: A CGP-hydrogel was designed to release 92% of the dexamethasone load over 4 consecutive days with concurrent degradation of the hydrogel matrix. In vivo: After surgical placement of CGP-hydrogel to the round window niche, we detected elevated levels of dexamethasone in perilymph for 5 days. Auditory function testing revealed a temporary hearing loss in the immediate postoperative period, which resolved by the 10th postoperative day. CONCLUSIONS: We report the development of CGP-hydrogel, a biodegradable matrix that achieves local, sustained delivery of dexamethasone to the inner ear. There were no significant complications resulting from the surgical procedure or the administration of CGP-hydrogel to our murine model.

Brain integrity and cerebral atrophy in Vietnam combat veterans with and without posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is associated with decreased hippocampal volume, but the relationship between trauma and brain morphology in the absence of PTSD is less clear. In this study, measures of brain integrity were determined by estimating gray and white matter regional brain volumes using structural magnetic resonance imaging in six patients with PTSD and in five controls with comparable trauma exposure but without clinical evidence of PTSD. The only statistically significant volume difference between groups was observed multivariately in the white matter of the right temporal lobe (superior temporal gyrus, fusiform gyrus, parahippocampal gyrus, white-matter stem, middle temporal gyrus, and inferior temporal gyrus), although small sample sizes limit the power to detect between-group differences. Both groups showed heterogeneity in cerebral atrophy.

Risk factors for the development of hypothyroidism after hemithyroidectomy.

OBJECTIVES: To assess the incidence of hypothyroidism after hemithyroidectomy and to identify risk factors for the development of hypothyroidism. DESIGN: Retrospective analysis. SETTING: A tertiary care academic medical center. PATIENTS: The study included 90 patients who underwent a hemithyroidectomy from 1999 to 2004. MAIN OUTCOME MEASURES: Hypothyroidism was defined as a serum thyrotropin level greater than 6.0 mIU/L at least 8 weeks after hemithyroidectomy. All patients were analyzed for age, sex, surgical indications, preoperative and postoperative thyrotropin levels, weight of resected specimen, final pathologic analysis, and length of follow-up. Multivariate analysis was performed to identify multiple risk factors for the development of hypothyroidism. RESULTS: The final pathologic analysis demonstrated 49 follicular adenomas, 17 cases of Hashimoto thyroiditis, 10 multinodular goiters, and 14 other abnormalities. The overall incidence of the development of hypothyroidism after hemithyroidectomy was 27% (24 of 90 patients). When the groups were broken down by pathologic diagnosis, the incidence of hypothyroidism developing during follow-up among the Hashimoto thyroiditis and multinodular goiter groups was 59% and 50%, respectively. Also, the patients who developed hypothyroidism were noted to have statistically significant higher preoperative serum thyrotropin levels (3.15 mIU/L vs 1.95 mIU/L; P<.001) than those who remained euthyroid. There was no relationship between age, sex, or weight of the resected tissue and the subsequent risk of hypothyroidism. CONCLUSIONS: The overall incidence of posthemithyroidectomy hypothyroidism was 27%, and the majority of cases developed in the first 6 to 12 months after surgery. Risk factors for the development of hypothyroidism include pathologic diagnosis (Hashimoto thyroiditis and multinodular goiter) as well as a high-normal serum thyrotropin level. Routine monitoring of serum thyrotropin levels should be performed in all patients who undergo a hemithyroidectomy.

Does prior benign prostate biopsy predict outcome for patients treated with radical perineal prostatectomy?

OBJECTIVES: To determine the effect of prior benign prostate biopsies on the surgical and clinical outcomes of patients treated with radical perineal prostatectomy for prostate cancer. METHODS: A total of 1369 patients with clinically localized prostate cancer underwent radical prostatectomy by a single surgeon between 1991 and 2001. A subset of 203 patients (14.9%), who had undergone at least one prior benign prostate biopsy for a rising prostate-specific antigen and/or abnormal digital rectal examination, constituted our study population. A total of 1115 patients with no prior biopsy represented our control group. After prostatectomy, patients were evaluated at 6-month intervals for biochemical evidence of recurrence, defined as a prostate-specific antigen level of 0.5 ng/mL or greater. RESULTS: Patients with a prior benign biopsy had more favorable pathologic features with more organ-confined (74% versus 64%; P <0.001) and less margin-positive (9.8% versus 18%) disease. Only 24 patients (12%) in the study group (versus 20% in control group; P = 0.01) had eventual evidence of biochemical failure. Kaplan-Meier analyses suggested that patients with prior benign biopsies have improved biochemical disease-free survival, especially for those with more aggressive disease (Gleason sum 7 or greater; P <0.01). Overall, patients in the study group had lower probability (odds ratio 0.57, P <0.001) of biochemical failure compared with those in the control group. CONCLUSIONS: A prior benign prostate biopsy may be independently associated with more favorable surgical and biochemical outcomes after prostatectomy. Additional studies are needed to confirm these findings.

Pilot study to explore effects of low-fat, flaxseed-supplemented diet on proliferation of benign prostatic epithelium and prostate-specific antigen.

OBJECTIVES: Dietary factors may influence the prostate and have an impact on prostatic growth and disease. A small number of studies have suggested that flaxseed-supplemented, fat-restricted diets may thwart prostate cancer growth in both animals and humans. Unknown, however, is the potential effect of such a diet on benign prostatic epithelium. METHODS: We undertook a pilot study to explore whether a flaxseed-supplemented, fat-restricted diet affects the proliferation rates in benign epithelium. We also explored the effects on circulating levels of prostate-specific antigen (PSA), total testosterone, and cholesterol. Fifteen men who were scheduled to undergo repeat prostate biopsy were instructed to follow a low-fat (less than 20% kcal), flaxseed-supplemented (30 g/day) diet and were provided with a supply of flaxseed to last throughout the 6-month intervention period. The PSA, total testosterone, and cholesterol levels were determined at baseline and at 6 months of follow-up. Reports from the original and repeat biopsies were compared, and proliferation (MIB-1) rates were quantified in the benign prostatic epithelium. RESULTS: Statistically significant decreases in PSA (8.47 +/- 3.82 to 5.72 +/- 3.16 ng/mL; P = 0.0002) and cholesterol (241.1 +/- 30.8 to 213.3 +/- 51.2 mg/dL; P = 0.012) were observed. No statistically significant change was seen in total testosterone (434.5 +/- 143.6 to 428.3 +/- 92.5 ng/dL). Although 6-month repeat biopsies were not performed in 2 cases because of PSA normalization, of the 13 men who underwent repeat biopsy, the proliferation rates in the benign epithelium decreased significantly from 0.022 +/- 0.027 at baseline to 0.007 +/- 0.014 at 6 months of follow-up (P = 0.0168). CONCLUSIONS: These pilot data suggest that a flaxseed-supplemented, fat-restricted diet may affect the biology of the prostate and associated biomarkers. A randomized controlled trial is needed to determine whether flaxseed supplementation, a low-fat diet, or a combination of the two regimens may be of use in controlling overall prostatic growth.