Application of a novel headrest system for odontoid screw fixation. Technical note.

The authors describe a unique headholder device adapted to facilitate the placement of anterior odontoid screws. The patient's head is affixed in the headholder equipped with an articulating arm that can be placed in a paramedian fashion. This configuration rigidly fixates the head and provides an unencumbered open-mouth view of the odontoid using radiographic images, thus making screw placement easier.

Atlantoaxial stabilization with the use of C1-3 lateral mass screw fixation. Technical note.

Atlantoaxial stabilization has evolved from simple posterior wiring to transarticular screw fixation. In some patients, however, the course of the vertebral artery (VA) through the axis varies, and therefore transarticular screw placement is not always feasible. For these patients, the authors have developed a novel method of atlantoaxial stabilization that does not require axial screws. In this paper, they describe the use of this technique in the first 10 cases. Ten consecutive patients underwent the combined C1-3 lateral mass-sublaminar axis cable fixation technique. The mean age of the patients was 62.6 years (range 23-84 years). There were six men and four women. Eight patients were treated after traumatic atlantoaxial instability developed (four had remote trauma and previous nonunion), whereas in the other two atlantoaxial instability was caused by arthritic degeneration. All had VA anatomy unsuitable to traditional transarticular screw fixation. There were no intraoperative complications in any of the patients. Postoperative computed tomography studies demonstrated excellent screw positioning in each patient. Nine patients were treated postoperatively with the aid of a rigid cervical orthosis. The remaining patient was treated using a halo fixation device. One patient died of respiratory failure 2 months after surgery. Follow-up data (mean follow-up duration 13.1 months) were available for seven of the remaining nine patients and demonstrated a stable construct with fusion in each patient. The authors present an effective alternative method in which C1-3 lateral mass screw fixation is used to treat patients with unfavorable anatomy for atlantoaxial transarticular screw fixation. In this series of 10 patients, the method was a safe and effective way to provide stabilization in these anatomically difficult patients.

Sinonasal leiomyosarcoma: review of literature and case report.

OBJECTIVES/HYPOTHESIS: To determine prognosis of primary sinonasal leiomyosarcomas after treatment. STUDY DESIGN: Literature review and case report. METHODS: Review of English literature from MEDLINE and independent sources with the addition of our case. RESULTS: Including our case, 63 cases have been reported. Primary treatment includes resection with or without radiation. Chemotherapy has not been reported to be effective. In our case, however, chemotherapy, consisting of etoposide and high-dose ifosfamide, caused the tumor to shrink significantly. On the basis of a review of all reported cases, the overall survival rate at a mean follow-up of 38.24 month is 66%. The minimal overall survival rates at 5 and 10 years are 20% and 6%, respectively. CONCLUSION: The prognosis for primary sinonasal leiomyosarcomas is poor. However, a 10-year survival has been reported in a few patients. Chemotherapy may be a useful adjunct when managing extensive lesions unamenable to curative resection.

Surgical management of giant herniated thoracic discs: analysis of 20 cases.

OBJECT: The authors evaluated the clinical and surgical outcomes obtained in patients with giant herniated thoracic discs (HTDs), defined as occupying more than 40% of the spinal canal. Surgery-related considerations and functional outcomes in patients with small- and medium-sized HTDs were compared. METHODS: The authors reviewed 140 cases of surgically treated HTDs, 20 (14%) of which were giant. Before and after surgery, all patients underwent computerized tomography myelography, magnetic resonance imaging, or both. Functional outcomes were assessed using the Frankel grading system preoperatively, immediately after surgery, and at long-term follow-up examination. The results observed in patients with giant HTDs were compared with those with small- and medium-sized HTDs. The mean overall follow-up period was 2.6 years. Sixty-six patients (47%) presented with myelopathy, including 19 (95%) with a giant HTD. Of the latter, 16 (80%) underwent anterior, eight thoracoscopic, and eight open thoracotomy approaches. Four patients (20%) with laterally oriented giant HTDs within the spinal canal underwent surgery via a posterolateral approach. Based on analysis of long-term follow-up data, 53% of patients with giant HTDs improved neurologically by one Frankel grade. Progression of myelopathy was arrested in 42%, and in 5% the Frankel grade worsened by one. In patients with small- and medium-sized HTDs, the Frankel grade improved by one in 77%, stabilized in 23%, and worsened in 0%. Patients with giant HTDs who underwent thoracoscopic surgery had worse short- and long-term functional outcomes than those in whom open thoracotomy was performed. CONCLUSIONS: Patients with giant HTDs presented more frequently with myelopathy and experienced worse functional outcomes than those with smaller HTDs. Based on their experience, the authors recommend open thoracotomy rather than thoracoscopy for the treatment of midline giant HTDs.

Biomechanical comparison of C1-2 posterior fixation techniques.

OBJECT: In a nondestructive, repeated-measures in vitro flexibility experiment, the authors compared the acute stability of C1-2 after placement of C-1 lateral mass and C-2 pars interarticularis (LC1-PC2) instrumentation with that of C1-2 transarticular screw fixation. METHODS: The effect of C-1 laminectomy and C1-2 interspinous cable/graft fixation on LC1-PC2 stability was studied. Screw pullout strengths were also compared. Seven human cadaveric occiput-C3 specimens were loaded nondestructively with pure moments while measuring nonconstrained atlantoaxial motion. Specimens were tested with graft alone, LC1-PC2 alone, LC1-PC2 combined with C-1 laminectomy, and graft-augmented LC1-PC2. Interspinous cable/graft fixation significantly enhanced LC1-PC2 stability during extension. After C-1 laminectomy, the LC1-PC2 construct allowed increased motion during flexion and extension. There was no significant difference in lax zone or range of motion between LC1-PC2 fixation and transarticular screw fixation, but graft-assisted transarticular screws yielded a significantly smaller stiff zone during extension. The difference in pullout resistance between C-1 lateral mass screws and C-2 pars interarticularis screws was insignificant. The LC1-PC2 region restricted motion to within the normal range during all loading modes. Atlantal laminectomy reduced LC1-PC2 stability during flexion and extension. CONCLUSIONS: The instrumentation-augmented LC1-PC2 construct performed biomechanically similarly to the C1-2 transarticular screw fixation. The LC1-PC2 construct resisted flexion, lateral bending, and axial rotation well. The weakness of the LC1-PC2 fixation in resisting extension can be overcome by adding an interspinous graft to the construct.

Cavernous malformation of the trigeminal nerve manifesting with trigeminal neuralgia: case report.

OBJECTIVE AND IMPORTANCE: We describe a patient with a cavernous malformation within the trigeminal nerve at the nerve root entry zone who presented with trigeminal neuralgia. CLINICAL PRESENTATION: A 52-year-old woman sought treatment after experiencing dizziness and lancinating left facial pain for almost a year. Neurological examination revealed diminished sensation in the distribution of the trigeminal nerve on the left. Magnetic resonance imaging demonstrated a minimally enhancing lesion affecting the trigeminal nerve. INTERVENTION: The patient underwent a retrosigmoid craniotomy. At the nerve root entry zone, the trigeminal nerve was edematous with hemosiderin staining. The lesion, which was resected with microsurgical technique, had the appearance of a cavernous malformation on gross and histological examination. The patient's pain improved significantly after resection. CONCLUSION: Cavernous malformations can afflict the trigeminal nerve and cause trigeminal neuralgia. Microsurgical excision can be performed safely and is associated with improvement in symptoms.

Intraoperative Iso-C C-arm navigation in cervical spinal surgery: review of the first 52 cases.

STUDY DESIGN: Fifty-two study participants underwent cervical spine surgery using intraoperative Iso-C imaging with or without spinal navigation. OBJECTIVES: To evaluate prospectively the feasibility, advantages, limitations, and applications of Iso-C in cervical spine surgery. SUMMARY OF BACKGROUND DATA: Existing stereotactic spinal navigational systems images must be acquired before surgery and typically require cumbersome point-to-point registration. Intraoperative computed tomography (CT) and magnetic resonance imaging (MRI) provide real-time information but can restrict access to the patient, preclude the use of traditional operating room tables, and are time-consuming. The Iso-C allows quick, CT-quality, real-time data acquisition without restricting access to the patient. The data acquired can be automatically transferred to navigational systems with the immediate ability to navigate for anterior or posterior cervical spine procedures. METHODS: High-resolution isotropic three-dimensional data sets were acquired using the Iso-C intraoperative fluoroscopy in 52 cervical spine cases. In 30 cases, the data were imported automatically to the StealthStation Treon to support neuronavigation. In 22 cases, a postprocedural intraoperative CT was obtained with the Iso-C primarily to assess the extent of osseous decompression and/or the accuracy of implants or instrumentation. In most cases, a postoperative high-resolution CT image was obtained and compared with the Iso-C data. RESULTS: Successful automated registration suitable for navigation was attained for all anterior and posterior cervical spinal cases. The postprocedural intraoperative Iso-C data were 100% concordant with those of postoperative high-resolution CT as determined by a blinded neuroradiologist. CONCLUSIONS: Iso-C intraoperative fluoroscopy is an accurate and rapid way to perform CT-quality image-guided navigation in cervical spinal surgery. In most cases, it obviates the need for postoperative imaging.

Intraoperative Iso-C C-arm navigation in craniospinal surgery: the first 60 cases.

OBJECTIVE: The intraoperative Iso-C C-arm (Siremobil Iso-C 3D; Siemens Medical Solutions, Erlangen, Germany) provides a unique ability to acquire and view multiplanar three-dimensional images of intraoperative anatomy. Registration for intraoperative surgical navigation may be automated, thus simplifying the operative workflow. METHODS: Iso-C C-arm intraoperative fluoroscopy acquires 100 images, each of which must be 1.8 degrees in a circumferential fashion about an "isocentric" point in space. The system generates a high-resolution isotropic three-dimensional data set that is available immediately after the 90-second C-arm rotation. The data set is ported to the image-guided workstation, registration is immediate and automated, and the surgeon can navigate with millimetric accuracy. The authors prospectively examined data from the initial 60 patients examined with the Iso-C, among whom were cases of anterior and posterior spinal instrumentation from the occiput to the sacrum. Percutaneous and minimally invasive spinal and cranial procedures were also included. RESULTS: Automated registration for image-guided navigation was attainable for anterior and posterior cases from the cranial base and entire spine. In most cases, intraoperative postprocedural imaging with the Iso-C mitigated the need for postoperative imaging. CONCLUSION: Intraoperative Iso-C three-dimensional scanning allows real-time feedback during cranial base and spinal surgery and during procedures involving instrumentation. In most cases, it obviates the need for postoperative computed tomography. Its usefulness is in its simplicity, and it can be easily adapted to the operating room workflow. When coupled with intraoperative navigation, this new technology facilitates complex neurosurgical procedures by improving the accuracy, safety, and time of surgery.

Thoracoscopic placement of dual-rod instrumentation in thoracic spinal trauma.

OBJECTIVE AND IMPORTANCE: Traditionally, thoracic fractures that require anterior stabilization are treated through an open thoracotomy approach. Thoracoscopic instrumentation avoids many of the complications associated with an open thoracotomy but is technically challenging. We report the first cases of dual-rod internal fixation systems placed thoracoscopically for thoracic spinal trauma. CLINICAL PRESENTATION: Two male patients sustained midthoracic spinal trauma falling from motorcycles in separate incidents. Both injuries led to unstable spinal columns, but the patients had no neurological deficits and had minimal spinal cord compression. One patient had a complex spiral fracture from T6 to T8; the other had T7 burst and T8 compression fractures. Based on the complex morphological features of the patients' fractures, anterior internal fixation was the treatment of choice for both. The two available options for an anterior stabilization were open thoracotomy and thoracoscopic instrumentation. Because extensive decompression was unnecessary, a thoracoscopic approach was used. INTERVENTION: A dual-rod internal fixation system (Medtronic Sofamor Danek, Inc., Memphis, TN) was placed with two screws each in the T6 and T9 vertebral bodies of each patient. Thoracoscopy was used for direct visualization of the operative site with fluoroscopic guidance for screw placement. Surgery was completed without complications, and both patients did well afterward. Upright and supine x-rays demonstrated that the constructs were stable at 10 weeks and 6 months, respectively. CONCLUSION: Thoracoscopic instrumentation offers the advantages of a minimally invasive approach but is technically challenging. The characteristics of dual-rod fixation systems (small-profile components and step-wise insertion) provide the best biomechanical profile and facilitate thoracoscopic instrumentation.

Comparison of rapid and gradual weaning from external ventricular drainage in patients with aneurysmal subarachnoid hemorrhage: a prospective randomized trial.

OBJECT: The goal of this study was to compare rapid and gradual weaning from external ventricular drainage in patients with aneurysmal subarachnoid hemorrhage (SAH) in a prospective, randomized trial. METHODS: Between December 2001 and December 2002, 81 patients with aneurysmal SAH in whom external ventricular drains (EVDs) had been placed were enrolled in the study: 41 patients were randomized to the rapidly weaned group and 40 were randomized to the gradually weaned group. The two groups were well matched with respect to age, sex, posterior aneurysm location, Fisher grade, Hunt and Hess grade, intraventricular hemorrhage on admission, and hydrocephalus on admission. Rapid weaning was defined as weaning that occurred within 24 hours with immediate closure of the EVD, whereas gradual weaning took place over a 96-hour period with daily, sequential height elevations of the EVD system followed by drain closure for 24 hours. All patients in whom EVD weaning failed underwent shunt placement. Rates of shunt implantation, days in the intensive care unit (ICU), and overall duration of hospitalization were compared. There was no significant difference in rates of shunt implantation between the rapidly weaned (63.4%) and gradually weaned (62.5%) groups. Nevertheless, patients in the gradually weaned group spent a mean of 2.8 more days in the ICU (p = 0.0002) and 2.4 more days in the hospital (p = 0.0314) than patients in the rapidly weaned group. CONCLUSIONS: Compared with rapid weaning, gradual, multistep EVD weaning provided no advantage to patients with aneurysmal SAH in preventing the need for long-term shunt placement and prolonged ICU and hospital stays.

Nonsurgical treatment of a C6-7 unilateral locked facet joint in an infant. Case report.

Cervical spine injuries in the pediatric population typically affect the upper cervical region. The authors present the first reported case of a subaxial C6-7 unilateral locked facet joint in a neurologically intact 10-month-old infant. To date, this patient's nonoperative treatment has been successful. The proposed biomechanical mechanism of this injury and the treatment paradigm are discussed.

A new table-fixed retractor for anterior odontoid screw fixation: technical note.

The authors describe a unique retraction device adapted for anterior odontoid screw placement. A rigidly fixed tubular retractor system obviates the need for dissecting the longus colli muscles as well as for excessive retraction of the trachea, esophagus, and recurrent laryngeal nerve. The proper trajectory for screw placement can be determined by fine manipulation of the retractor as determined by biplanar fluoroscopy. The retractor is then rigidly fixed in position. The tubular corridor permits the odontoid screw to be placed in the usual fashion.

Intramedullary histoplasmosis spinal cord abscess in a nonendemic region: case report and review of the literature.

An immunocompetent patient from a nonendemic region developed a rare intramedullary thoracic histoplasmoma. A native Arizonan, with no history of travel to endemic regions, received 3 months of itraconazole for confirmed gastrointestinal histoplasmosis at an outside institution. Two years later she experienced the rapid onset of paraplegia and lost bowel and bladder function. Magnetic resonance imaging demonstrated a ring-enhancing intramedullary lesion at T2 and signal abnormality from C2 to T5. Emergent T2-T3 laminectomy was performed with ultrasonographically guided intradural exploration and midline myelotomy. The intramedullary abscess was drained. She was nonambulatory, but motor function was partially restored. An Ommaya reservoir was later placed to deliver amphotericin and a new antifungal agent, voriconazole. Magnetic resonance imaging confirmed that the infection had resolved. Intramedullary spinal histoplasmoma is a rare manifestation of disseminated histoplasmosis, particularly in nonendemic regions. Surgery for focal mass lesions and aggressive antifungal chemotherapy are the optimal treatment. Newer central nervous system-penetrating antibiotics show promise in refractory cases.