Spinal deformity surgery in patients for whom blood transfusion is not an option: a single-center experience.

OBJECTIVE: Spinal deformity surgery is associated with significant blood loss, often requiring the transfusion of blood and/or blood products. For patients declining blood or blood products, even in the face of life-threatening blood loss, spinal deformity surgery has been associated with high rates of morbidity and mortality. For these reasons, patients for whom blood transfusion is not an option have historically been denied spinal deformity surgery. METHODS: The authors retrospectively reviewed a prospectively collected data set. All patients declining blood transfusion who underwent spinal deformity surgery at a single institution between January 2002 and September 2021 were identified. Demographics collected included age, sex, diagnosis, details of any prior surgery, and medical comorbidities. Perioperative variables included levels decompressed and instrumented, estimated blood loss, blood conservation techniques used, length of surgery, length of hospital stay, and complications from surgery. Radiographic measurements included, where appropriate, sagittal vertical axis correction, Cobb angle correction, and regional angular correction. RESULTS: Spinal deformity surgery was performed in 31 patients (18 male, 13 female) over 37 admissions. The median age at surgery was 41.2 years (range 10.9-70.1 years), and 64.5% had significant medical comorbidities. A median of 9 levels (range 5-16 levels) were instrumented per surgery, and the median estimated blood loss was 800 mL (range 200-3000 mL). Posterior column osteotomies were performed in all surgeries, and pedicle subtraction osteotomies in 6 cases. Multiple blood conservation techniques were used in all patients. Preoperative erythropoietin was administered prior to 23 surgeries, intraoperative cell salvage was used in all, acute normovolemic hemodilution was performed in 20, and perioperative administration of antifibrinolytic agents was performed in 28 surgeries. No allogenic blood transfusions were administered. Surgery was staged intentionally in 5 cases, and there was 1 unintended staging due to intraoperative blood loss from a vascular injury. There was 1 readmission for a pulmonary embolus. There were 2 minor postoperative complications. The median length of stay was 6 days (range 3-28 days). Deformity correction and the goals of surgery were achieved in all patients. Two patients underwent revision surgery during the follow-up period: one for pseudarthrosis and the other for proximal junctional kyphosis. CONCLUSIONS: With proper preoperative planning and judicious use of blood conservation techniques, spinal deformity surgery may be performed safely in patients for whom blood transfusion is not an option. The same techniques can be applied widely to the general population in order to minimize blood loss and the need for allogeneic blood transfusion.

Utility of intraoperative electromyography in placing C7 pedicle screws.

OBJECTIVE: The C7 vertebral body is morphometrically unique; it represents the transition from the subaxial cervical spine to the upper thoracic spine. It has larger pedicles but relatively small lateral masses compared to other levels of the subaxial cervical spine. Although the biomechanical properties of C7 pedicle screws are superior to those of lateral mass screws, they are rarely placed due to increased risk of neurological injury. Although pedicle screw stimulation has been shown to be safe and effective in determining satisfactory screw placement in the thoracolumbar spine, there are few studies determining its utility in the cervical spine. Thus, the purpose of this study was to determine the feasibility, clinical reliability, and threshold characteristics of intraoperative evoked electromyographic (EMG) stimulation in determining satisfactory pedicle screw placement at C7. METHODS: The authors retrospectively reviewed a prospectively collected data set. All adult patients who underwent posterior cervical decompression and fusion with placement of C7 pedicle screws at the authors' institution between January 2015 and March 2019 were identified. Demographic, clinical, neurophysiological, operative, and radiographic data were gathered. All patients underwent postoperative CT scanning, and the position of C7 pedicle screws was compared to intraoperative neurophysiological data. RESULTS: Fifty-one consecutive C7 pedicle screws were stimulated and recorded intraoperatively in 25 consecutive patients. Based on EMG findings, 1 patient underwent intraoperative repositioning of a C7 pedicle screw, and 1 underwent removal of a C7 pedicle screw. CT scans demonstrated ideal placement of the C7 pedicle screw in 40 of 43 instances in which EMG stimulation thresholds were > 15 mA. In the remaining 3 cases the trajectories were suboptimal but safe. When the screw stimulation thresholds were between 11 and 15 mA, 5 of 6 screws were suboptimal but safe, and in 1 instance was potentially dangerous. In instances in which the screw stimulated at thresholds ≤ 10 mA, all trajectories were potentially dangerous with neural compression. CONCLUSIONS: Ideal C7 pedicle screw position strongly correlated with EMG stimulation thresholds > 15 mA. In instances, in which the screw stimulates at values between 11 and 15 mA, screw trajectory exploration is recommended. Screws with thresholds ≤ 10 mA should always be explored, and possibly repositioned or removed. In conjunction with other techniques, EMG threshold testing is a useful and safe modality in determining appropriate C7 pedicle screw placement.

Simultaneous above and below approach to giant pituitary adenomas: surgical strategies and long-term follow-up.

INTRODUCTION: Giant pituitary adenomas of excessive size, fibrous consistency or unfavorable geometric configuration may be unresectable through conventional operative approaches. We present our select case series for operative resection and long-term follow-up for these unusual tumors, employing both a staged procedure and a combined transsphenoidal-transcranial above and below approach. METHOD: A retrospective chart review was performed on patients operated via the staged, and combined approaches by the senior author (J.N.B.). Preoperative characteristics and postoperative outcomes were reviewed. A detailed description of the operative technique and perioperative management is provided. RESULTS: Between 1993 and 1996, two patients harboring giant pituitary adenomas underwent an intentionally staged resection, and between 1997 and 2006, nine patients harboring giant pituitary adenomas underwent surgery via a single-stage above and below approach. Nine patients (82%) presented with non-secreting adenomas and two patients (18%) presented with prolactinomas refractory to medical management. Gross total resection was achieved in six patients (55%), near total resection in 1 (9%), and subtotal removal in 4 (36%). Seven patients (64%) experienced visual improvement postoperatively and no major complications occurred. Long-term follow-up averaged 51.6 months. Panhypopituitarism was observed in four patients, partial hypopituitarism in four, persistent DI in two, and persistent SIADH in one. CONCLUSIONS: The addition of a transcranial component to the transsphenoidal approach offers additional visualization of critical neurovascular structures during giant pituitary adenoma resection. Complications rates are similar to other series in which complex pituitary adenomas are resected by other means. The above and below approach is both safe and effective and the immediate and long-term advantages of a single-stage approach justify its utility in this select group of patients.

Venous air emboli from intravenous catheterization: a report of iatrogenic intravascular pneumocephalus.

Pneumocephalus in the absence of a recent intracranial or intrathecal procedure is a significant radiographic finding and may be clinically relevant. Pneumocephalus secondary to intravenous catheterization may be a more common finding than previously expected. Although pneumocephalus is often associated with pathological conditions, recognition of a characteristic pattern of intravenous pneumocephalus in the presence of intravenous catheterization may aid the clinician in determining a patient's underlying condition. This unexpected radiographic finding should not necessarily be cause for alarm, and there is no evidence that intravenous pneumocephalus alone is harmful. We present a patient with intravenous pneumocephalus and a review of the literature.

Cancer-testis and melanocyte-differentiation antigen expression in malignant glioma and meningioma.

Identification of well-defined glioma-specific antigens is a crucial and necessary step in developing immunotherapy for glioblastoma multiforme (GBM). In this study, we analyzed the composite expression of cancer-testis antigens (CTA) and melanocyte-differentiation antigens (MDA) in malignant glioma tissue and primary glioma cell lines and compared them with normal brain specimens and meningioma. CTA and MDA expression was assessed by the reverse transcription-polymerase chain reaction. The following primers were analyzed for CTA: LAGE-1, NY-ESO-1, MAGE-1, MAGE-3, MAGE-4, MAGE-10, CT-7, CT-10, HOM-MEL 40, BAGE, and SCP-1; and for MDA: tyrosinase, gp100, MELAN-A/MART-1, and TRP-2. The expression level was determined by ethidium bromide-stained agarose gel. Among malignant glioma tissue, the highest CTA and MDA expression rates were found for MAGE-3 (22%), MAGE-1 (16%), CT-7 (11%), gp100 (40%), and TRP-2 (29%). Among primary glioma cell lines, the highest levels of expression were: CT-10 (38%), gp100 (100%), and TRP-2 (31%). NY-ESO-1 was the only CTA demonstrated and seen in 12% of meningioma tissue specimens. TRP-2 and gp100 were expressed in 65% and 38% of meningioma tissue, respectively; gp100 and TRP-2 were expressed in 100% and 50% of meningioma cell lines. Of the nine normal brain specimens, all samples tested positive for TRP-2. All other CTA and MDA tested negative in normal brain. We conclude that CTA and MDA demonstrate low-to-variable levels of expression within GBM. However, two CTA (MAGE-1 and MAGE-3) and one MDA (gp100) may be considered candidate antigens based on their restricted expression in GBM. These results will greatly accelerate the development of novel, specific immunotherapeutic strategies.

Beneficial use of a new hand-held CO2 laser fiber in resection of a calcified and vascular intraventricular tumor.

BACKGROUND: The progression of laser technology in neurosurgery has been limited by the poor maneuverability of traditional line-of-sight carbon dioxide (CO2) lasers and the propensity of other laser energies to cause collateral thermal injury to adjacent neural structures. The advent of a dielectric omnidirectional reflector and the subsequent development of phototonic bandgap fibers (PBF) have transformed the CO2 laser into a low-profile instrument with considerable dexterity and many potential new neurosurgical applications. CASE DESCRIPTION: A 48-year-old woman presented with a large mass in the left lateral ventricle that was first diagnosed>20 years ago. The patient was asymptomatic until 1 month before presentation, when she began to experience progressive memory loss and neurocognitive decline. RESULTS: The hand-held CO2 laser was used to debulk the tumor. The CO2 laser vaporized neoplastic cellular material and simultaneously cauterized microvascular structures. CONCLUSIONS: The CO2 laser was exceptionally useful in the resection of this long-standing and extremely calcified, yet vascular mass. A review of the evolution of laser technology applications in neurosurgery is presented, with a specific focus on the innovations that led to the development of the new PBF CO2 laser. This new technology may be advantageous in tumor surgery, particularly in the resection of long-standing calcified and vascular tumors that are not amendable to traditional surgical techniques.

Simulation in neurosurgery: a review of computer-based simulation environments and their surgical applications.

BACKGROUND: Computer-based surgical simulators create a no-risk virtual environment where surgeons can develop and refine skills through harmless repetition. These applications may be of particular benefit to neurosurgeons, as the vulnerability of nervous tissue limits the margin for error. The rapid progression of computer-processing capabilities in recent years has led to the development of more sophisticated and realistic neurosurgery simulators. OBJECTIVE: To catalogue the most salient of these advances and characterize our current effort to create a spine surgery simulator. METHODS: An extensive search of the databases Ovid-MEDLINE, PubMed, and Google Scholar was conducted. Search terms included, but were not limited to: neurosurgery combined with simulation, virtual reality, haptics, and 3-dimensional imaging. RESULTS: A survey of the literature reveals that surgical simulators are evolving from platforms used for preoperative planning and anatomic education into programs that aim to simulate essential components of key neurosurgical procedures. This evolution is predicated upon the advancement of 3 main components of simulation: graphics/volume rendering, model behavior/tissue deformation, and haptic feedback. CONCLUSION: The computational burden created by the integration of these complex components often limits the fluidity of real-time interactive simulators. Although haptic interfaces have become increasingly sophisticated, the production of realistic tactile sensory feedback remains a formidable and costly challenge. The rate of future progress may be contingent upon international collaboration between research groups and the establishment of common simulation platforms. Given current limitations, the most potential for growth lies in the innovative design of models that expand the procedural applications of neurosurgery simulation environments.

Radiolucent hair accessories causing depressed skull fracture following blunt cranial trauma.

Pediatric neurosurgeons frequently care for children with traumatic scalp and skull injury. Foreign objects are often observed on imaging and may influence the clinician's decision-making process. The authors report on 2 cases of poorly visualized hair beads that had become embedded into the skull during blunt trauma. In both cases, skull radiography and CT scanning demonstrated depressed, comminuted fractures with poorly demonstrated spherical radiolucencies in the overlying scalp. The nature of these objects was initially unclear, and they could have represented air that entered the scalp during trauma. In one case, scalp inspection demonstrated no evidence of the bead. In the other case, a second bead was observed at the site of scalp laceration. In both cases, the beads were surgically removed, the fractures were elevated, and the patients recovered uneventfully. Radiolucent fashion accessories, such as hair beads, may be difficult to appreciate on clinical examination and may masquerade as clinically insignificant air following cranial trauma. If they are not removed, these foreign bodies may pose the risk of an infection. Pediatric neurosurgeons should consider hair accessories in the differential diagnosis of foreign bodies that may produce skull fracture following blunt trauma.