Metastatic spinal tumors are an increasingly common and difficult problem encountered by neurosurgeons and orthopedic surgeons. To improve therapies and increase life expectancy for patients with tumors such as those of the breast and prostate, a global, systematic approach is required to maximize the preservation of neurological function, maintenance of spinal stability, and relief of pain, all with the ultimate goal of improved functional capacity and quality of life (QOL). Although radiotherapy and surgery are still the primary therapeutic options, several new adjuvant therapies initially implemented to control pain more effectively have also been shown to reduce overall skeleton-related complications (pathological fractures and hypercalcemia) and may ultimately improve and extend QOL. This more global approach to spinal metastases also includes optimizing each patient's overall medical condition and potential for healing (that is, nutrition), as well as avoiding potential complications associated with metastatic disease (such as deep vein thrombosis), including excessive blood loss in the case of renal metastasis. A thorough knowledge and understanding of these therapeutic adjuvants is required to optimize care and to respond to our increasingly medically knowledgable patient population whose access to prevalent medical information has been increased because of the internet.
James M. Schuster and M. Sean Grady
Shabbar F. Danish, Jessica A. Wilden and James Schuster
✓The authors describe 2 cases of intraoperative thoracic vertebral body extension fractures in morbidly obese patients with ankylosing spondylitis (AS), undergoing total hip arthroplasty, with resultant acute traumatic paraplegia. The pathophysiology with regard to the surgical positioning and the associated risks of obesity and AS are reviewed. Additionally, strategies for avoiding these types of injuries are discussed.
David W. Newell, James M. Schuster and Anthony M. Avellino
✓ The use of a microanastomotic device for direct connection of intracranial vessels can be helpful to facilitate removal of distally located middle cerebral artery (MCA) aneurysms. The authors report on two patients who presented for treatment with large aneurysms distally located on the MCA. The aneurysms were completely excised and the proximal and distal portions of the parent vessel were connected in an end-to-end fashion by using a microanastomotic device. The time required to crossclamp the vessel for excision of the aneurysm and primary anastomosis was 10 minutes in one case and 15 minutes in the other. The short crossclamp time and high-quality anastomosis afforded by this device may be useful in the treatment of these difficult lesions and the prevention of cerebral ischemia.
James Schuster, Jun Zhang and Maria Longo
One of the major difficulties of conducting bone metastasis research is the lack of adequate models for studying the bone–tumor microenvironment. The limitations of current in vivo models include the following: non-human tumor or bone, variable reproducibility, limited supply, and an inability to be easily manipulated. The objective of the present study was to develop a uniform and reproducible model of bone/spine metastasis by utilizing bone derived from human osteoblasts grown subcutaneously in severe combined immunodeficiency (SCID) mice with subsequent introduction of human carcinoma cell lines.
Human osteoblasts were serially passed in culture and induced to differentiate into mature osteoblasts. They were subsequently loaded on hydroxyapatite-coated collagen sponges and implanted subcutaneously into the SCID mice. After allowing the bone to mature for 8 weeks, tumor cell suspensions were implanted percutaneously into the bone. The bone–tumor complexes were subsequently harvested, decalcified, and prepared for histological examination.
The authors have developed a novel, reproducible SCID mouse model of bone/spine metastasis by using bone derived from human osteoblasts and subsequently introduced human tumor lines. They believe this model will be useful for studying the basic biology of bone metastases.
Report of two cases and review of the literature
Gregory G. Heuer, Michael F. Stiefel, Robert L. Bailey and James M. Schuster
✓Spinal ependymomas are a common type of primary spinal cord neoplasm that frequently occurs in the lumbar spine. The authors report on two patients who presented with acute neurological decline after hemorrhage into ependymomas of the filum terminale. Both were transferred to the authors' institution because of diagnostic uncertainty and a concern about possible intradural vascular abnormalities. Both patients underwent lumbar laminectomies for tumor resection. The pathological finding in each case was myxopapillary ependymoma. Both patients made a significant recovery and were ambulatory and continent at follow-up review. These cases illustrate the rare but clinically significant incidence of acute neurological decline caused by hemorrhagic cauda equina ependymomas, including the potential for delayed diagnosis and treatment.
Gregory G. Heuer, Brandon C. Gabel, Deb A. Bhowmick, Michael F. Stiefel, Robert W. Hurst and James M. Schuster
✓Spinal arteriovenous fistulas (AVFs) are relatively uncommon lesions that are often diagnosed in a delayed fashion. The authors present a cause of a symptomatic high-flow AVF that developed in a patient after traumatic injury to the upper cervical spine. The patient presented to the trauma bay after a motor vehicle collision, and was found to have a C-2 fracture involving the transverse foramen. Although the patient was neurologically intact on presentation, 6 hours after admission weakness developed on his left side. Imaging studies demonstrated complete transection of the distal cervical aspect of the right vertebral artery (VA) at the base of C-2, with antegrade and retrograde flow into a direct AVF, resulting in early filling of the right internal jugular vein and other external draining veins. The patient was treated endovascularly with coil occlusion of the VA both proximal and distal to the transection. The patient's weakness improved over the next 7 days. At the 12-week follow-up examination, the patient's fractures had healed and he was neurologically intact.
James M. Schuster, Anthony M. Avellino, Frederick A. Mann, Allain A. Girouard, M. Sean Grady, David W. Newell, H. Richard Winn, Jens R. Chapman and Sohail K. Mirza
Object. The use of structural allografts in spinal osteomyelitis remains controversial because of the perceived risk of persistent infection related to a devitalized graft and spinal hardware. The authors have identified 47 patients over the last 3.5 years who underwent a surgical decompression and stabilization procedure in which fresh-frozen allografts were used after aggressive removal of infected and devitalized tissue. The patients subsequently underwent 6 weeks of postoperative antibiotic therapy (12 months for those with tuberculosis [TB]).
Methods. Follow-up data included results of serial clinical examinations, radiography, laboratory analysis (erythrocyte sedimentation rate and white blood cell count), and clinical outcome questionnaires. Of the original 47 patients (14 women and 33 men, aged 14–83 years), 39 were available for follow up. The average follow-up period at the time this article was submitted was 17 ± 9 months (median 14 months, range 6–45 months). In the majority of cases (57%), a Staphylococcus species was the infectious organism. Predisposing risk factors included intravenous drug abuse (IVDA), previous surgery, diabetes, TB, and concurrent infections. During the follow-up period only two patients suffered recurrent infection at a contiguous level; both had a history of IVDA and one also had a chronic excoriating skin condition. No other recurrent infections have been identified, and no patient has required reoperation for persistent infection or allograft/hardware failure.
Conclusions. It is the authors' opinion that the use of structural allografts in combination with aggressive tissue debridement and adjuvant antibiotic therapy provide a safe and effective therapy in cases of spinal osteomyelitis requiring surgery.
Peter Syre III, Leonardo Rodriguez-Cruz, Rajiv Desai, Karl A. Greene, Robert Hurst, James Schuster, Neil R. Malhotra and Paul Marcotte
Gunshot wounds to the atlantoaxial spine are uncommon injuries and rarely require treatment, as a bullet traversing this segment often results in a fatal injury. Additionally, these injuries are typically biomechanically stable. The authors report a series of 10 patients with gunshot wounds involving the lateral mass and/or bodies of the atlantoaxial complex. Their care is discussed and conclusions are drawn from these cases to identify the optimal treatment for these injuries.
A retrospective review was conducted of patients presenting to the emergency rooms of 3 institutions with gunshot wounds involving the atlantoaxial spine. Mechanism of injury and neurological status were obtained, as was the extent of the osteoligamentous, vascular, and neurological injuries. Nonoperative and operative treatment, complications, and clinical and radiographic outcome were recorded. The data were then analyzed to determine the neurological and biomechanical prognosis of these injuries, the utility of the various diagnostic modalities in the acute management of the injuries, and the nature and effectiveness of the nonoperative and operative treatment modalities.
Ten patients with gunshot wounds involving the lateral mass and/or bodies of the atlantoaxial complex were identified. All but 2 patients sustained a vertebral artery injury. Each patient was evaluated using cervical radiographs, CT scans, and vascular imaging, 8 in the form of digital subtraction angiography and 2 with high-resolution CT angiography. Uncomplicated patients were treated conservatively using cervical collar immobilization, local wound care, and antibiotics. One patient was treated using a halo for instability and 1 underwent posterior fusion following a posterolateral decompression for delayed myelopathy. One patient underwent transoral resection of a bullet fragment. One patient underwent embolization for a symptomatic arteriovenous fistula and a second patient underwent a neck exploration and a jugular vein ligation. None of the patients received anticoagulation therapy. The mean follow-up duration was 13 months. All but 2 patients regained their previous functional status and all ultimately attained a mechanically stable spine.
These 10 patients represent a rare form of cervical spine penetrating injury. Unilateral gunshot wounds to the atlantoaxial complex are usually stable and the need for acute surgical intervention is rare. Unilateral vertebral artery injury is well tolerated and any information provided by angiography does not alter the acute management of the patient. Vascular complications from gunshot wounds can be managed effectively by endovascular techniques.
Jared M. Pisapia, Nikhil R. Nayak, Ryan D. Salinas, Luke Macyszyn, John Y. K. Lee, Timothy H. Lucas, Neil R. Malhotra, H. Isaac Chen and James M. Schuster
As odontoid process fractures become increasingly common in the aging population, a technical understanding of treatment approaches is critical. 3D image guidance can improve the safety of posterior cervical hardware placement, but few studies have explored its utility in anterior approaches. The authors present in a stepwise fashion the technique of odontoid screw placement using the Medtronic O-arm navigation system and describe their initial institutional experience with this surgical approach.
The authors retrospectively reviewed all cases of anterior odontoid screw fixation for Type II fractures at an academic medical center between 2006 and 2015. Patients were identified from a prospectively collected institutional database of patients who had suffered spine trauma. A standardized protocol for navigated odontoid screw placement was generated from the collective experience at the authors' institution. Secondarily, the authors compared collected variables, including presenting symptoms, injury mechanism, surgical complications, blood loss, operative time, radiographically demonstrated nonunion rate, and clinical outcome at most recent follow-up, between navigated and nonnavigated cases.
Ten patients (three female; mean age 61) underwent odontoid screw placement. Most patients presented with neck pain without a neurological deficit after a fall. O-arm navigation was used in 8 patients. An acute neck hematoma and screw retraction, each requiring surgery, occurred in 2 patients in whom navigation was used. Partial vocal cord paralysis occurred after surgery in one patient in whom no navigation was used. There was no difference in blood loss or operative time with or without navigation. One patient from each group had radiographic nonunion. No patient reported a worsening of symptoms at follow-up (mean duration 9 months).
The authors provide a detailed step-by-step guide to the navigated placement of an odontoid screw. Their surgical experience suggests that O-arm–assisted odontoid screw fixation is a viable approach. Future studies will be needed to rigorously compare the accuracy and efficiency of navigated versus nonnavigated odontoid screw placement.